1 SKETCH-MAP of GRAN
(CHRISTIANIA DISTRICT)
sr IV.C.Bkocger & T.MLwster.
REFERENCE.
Scale. 1: 150,000
— ■4225 inch to the mile, or about 2-36 I
miles to the inch.
EH Quartz-Syenite (Xordinarkite).
Dykes of Siilvsberget (. Egyrine trachyte)
Dykes of Khontben-ptirphyry.
Vl^hSheetso/CaivptonitcKr'Uostonite'breccia
BH Basic J\\\ks <•>/ Laccolites Hones.
J Silurian Strata.
Y/A'tfX Arctuean Crystalline Schists.
The Quarterly journal of
the Geological Society of London
Geological Society of London, HighWire Press
i Ji
iby Google
7 i v it i t i .r i ^«
The Branner Geological Library
at
THE
QUARTERLY JOURNAL
OK TflK
GEOLOGICAL SOCIETY OF LONDON.
EDITKI) ItY
THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY,
Quod ai cui mortalmtn cordi et curie ait non tantum inventia basrere, atque iia uti, aed ad ulterior*
penctrare; atque non disputando Adveraarium, aed ope re naturam riocere; deoique non belle et prohabiliter
opinari, aed eerto et oeteoaive acire; talea, tanquam reri acientiarum fllb, oobla (ei ridebitur) ae adjuogaot.
— Aopkhi Organum, frafatio.
VOLUME THE FIFTIETH.
1894.
LONDON :
LONGMANS, GREEN, AND CO.
PARIS j PRIED. KLINCKM1ECK, ll RUE DE LILLE; P. SAW, 77 BOULEVARD 8T. GERMAIN :
LEIPZIG j T.O.WEIGEL.
BOLD ALSO AT THE APARTMENTS OP THE SOCIETY.
MDCCCiClT.
er
Digitized by Google
2USt
OS THB
OFFICERS
ot
GEOLOGICAL SOCIETY OF LONDON.
Elected February 16th, 1894.
£rc*i&tnt.
Henry W oodward, LL.D.T F.R.S.
Prof. A. H. Green, M.A., F.R.S.
<5.J.Hinde,Ph.D.
J. E. Mart, Esq., M.A., F.R.S.
I Prof. J. W. Judd. F.R.S.
I R. Lydekker, Esq., B.A., F.R.S.
^tcrctarit*.
I J. J. H. Teall, Esq., M.A., F.R.S.
dForrign £ccmarju
J. W. Uulke, Esq., F.R.S.
211986 Prof. T. Wiltshire, M.A., F.L.S.
H.Bauemmn,Esq.
W. T. Blanford, LL.D., F.R.S.
Sir John Evans, K.C.B., LL.D., F.R.S.,
F.L.S.
Prof. A. H. Green, M.A., F.R.S.
J. W. Gregory, D.Sc.
Alfred Harker, Esq., M.A.
G. J. Hinde, Ph.D.
T. Y. Holmes, Esq.
W. H. Hudleston, Esq., M.A., F.R.S.,
F L S
J. W. Hulke, Esq., F.R.S.
Prof/ J.- \JV Judd, K.R.S,
• • . • • :
» •
Prof. C. Lap worth, LL.D., F.R.S.
R. Lydekker, Esq., B.A., F.R.S.
Lieut -General C. A. \lcMabon.
J. E. Marr, Esq., M.A., F.R.S.
H. W. Monckton, Esq.. F.L.S.
Clement Reid, Esq., F.L.S.
F. Kutlev, Esq.
J. J. H. Teall, Esq., M.A., F.R.S.
Prof.T. Wiltshire, M.A., F.L.S.
Rev. 11. H. Winwood, MJL
Henry Woodward, LL.D., F.R.S.
Horace B. Woodwardj Esq*. •.
QdiiaUnU&tcvtUkvy, CItrfe, librarian, an* Curator.
L. L. Beliufante, B.Sc.B.ee L.
SUattftanW in Office, fctbrarp, an* {BLu&tum.
W. Rupert Jones.
Francis E. Brown.
Digitized by Google
TABLE OF CONTENTS.
Abbott, W. J. Lewis, Esq. The Ossiferous Fissures in the Valley
of the Shode, near Ighthani, Kent 171
Andrews, the Rev. W. It., and A. J. Jukes-Browne, Esq. The
Turbeck Jieds ut" the \ ale of NN ardour 44
Abnold-Bemrobe, II. H.. Esq. On the Microscopical Structure of
the Carboniferous Dolerites and Tuffs of Derbyshire. (Plates
AA1\. <X AA\ .)
Berxabd, II. M., Esq. The Systematic Position of the Trilobites .
tm
411
Boxney, Prof. T. G. On some Cases of the Conversion of Compact
L>7i)
. Mesozoic Rocks and Crystalline Schists in the Lepontine
285
• • and Mi-s ('. A. Raisin. On the Relations of of the
Older Fra^me ii tal Rucks iu North-western Ciiernarvon-hire . .
578
Brodie, the Rev. P. B. On the Discovery of Molluscs in the Upper
170
Bbogger, Prof. "W. C. The Basic Eruptive Rocks of Gran. (A
Preliminary Notice.) 15
Chapman, Frederick, Esq. The Baiyate Beds °/ Surrey and
their Microsco])ic Contents (l'lates \ \\\lV.)~TT 077
Da vies, A.M., Esq., and Dr. J. W. Gregory. The Geology of
Monte Clmberton . . . 303
Davison, Charles, Eaq. On Deposits from Snowdrift, with
especial Reference to the Origin of the Loess and the Pre-
servation of Mammoth-remains. 472
a 2
IT TABLE OF CONTENTS.
Page
Dawson, Dr. George M. Notes on the Occurrence of Mamnioth-
remains in the Yukon District of Canada and in AliL-ka 1
Dawson, Sir J. W. Note on the Genus Am'adites. as occurring
in the Coal Formation of Nova Scotia, (Plate XX.) 435
Draper, David, Esq. Notes on the Geol< gv of South-eastern
Africa. (Plates XXII. & XXIII.) 548
. The Occurrence of Dolomite in South Africa. . . 501
Evans, Dr. J. W. The Geology of Matto Grosso (particularly
tin- Ut.-gu.in dniiii'd hy tin- I \*\vr I'am^iuiy ). ( I'Jate \ 111.) . , t*~>
Ckjkik. Sir A le < ii 1 1 : v I- 1 ■■ Tin the Kehition> of tin- ]>a,-ic ami Acid
K'H-ks dl' the 'J'i'iticiry Vulcanic Scries ut tin.- Inner Hebrido.
(Platen XIII. & XIV.) 212
-, and J. J. II. Teall, Esq. On the Handed Structure of
some Tertiarv Gubbros in the Isle of Skve. (Plates XXVI.-
XXVIII.)..: : 045
Gregory, Dr. J. "W. The Waldrnsian Gneisses and their Place in
the Ccttitin Sequence. (Plate XV.) 232
. Contributions to the Geology of British East Africa. —
Part I. The Glacial Geology of Mount Kenya 515
, and A. M. Da vies, Esq. The Geology of Monte Cha-
bertou ^03
Gresley, W. S., E^q. Cone-in- cone : how it occurs in the De-
vonian (?) Series in Pennsylvania (U.S.A.) : with Further
Details of its Structure, Varieties, etc. (Plates XXXV. &
XXXVI.) 731
Harker, Alfred, Esq. Carrock Fell : a Study in the Variation of
Igneous Kock-masses. — I'art 1. The Gabbro. (I'lat.'> XVI. ,v
XVII.) . . 311
Hind, Dr. W he e lt on . Appendix to Sir J. W. Dawson's Note on
the (iemi< Xftitir/itv*. (Plate XX.) ~ 437
Holmes, T. V., Esq. Further Notes on some Sections on the New
Kailwav from Jlomlurd to (J minister, and on the Relations of
the Thames Valley Jkd.-' to the Ikailder Clay 443
Hull. Prof. Edward. Artesian Poring at New Lodge, near
YY mdsor lorest (berks) 1 50
Jones, Prof. T. Kupert. Cm the Kha?tic and suinc hiassic Ost ra-
coda of l'.ntam. (Plate IX. )
156
TABLE OF CONTENTS. T
Pa**
Jukf.s-Browxb. A. J., and the Rev. W. R. Andkews. The Pur-
Wk B*ds of thfi Va1<> of Ward on r , 44
, and W. Whitaker, Esq. On Deep Borings at Culford
and Winkfield, with Notes on those ot Ware and Cheshunt . . 488
Kynastqn, Herbert. On the Stratigraphical, Lithological, and
Pnla'ontolngic&l Features of the (iosau Hods of the (iosau Dis-
trict, in the Austrian Salzkammergtit 1^0
Laffan, G. B., Esq. See below.
Lesson. Dr. J. R., and G. B. Laffan, Esq. On the Geology of the
Pleistocene Deposits in the Valley of the Thames at Twicken-
ham, with Contributions to the Fauna and Flora of the Period . 453
Lyons, Capt. II. G. On the Stratigraphy and Physiography of the
Libyan Desert of Egypt (Plate XXI.) 531
M' 'Maho.v, Lieut.-Gen. C. A. Notes on some Trachyte-', Metamor-
phosed Tuffs, and other Rocks of Iyneous Origin on the Western
Flank of Dartmoor 338
Monckton, H. W., Esq. On a Picrite and other Associated Rocks
at Barn ton, near Edinburgh 39
Newton, E. T., Esq. The Vertebrate Fauna collected by Mr. Lewis
Abbott from the Fissure near Ightham, Kent. (Plates X.-X1I.) 188
Oldham, R. D., Esq. A Comparison of the Permian Breccias of the
Midlands with tha Upper Carboniferous Glacial Deposits of
India and Australia 403
Peach, B. N., Esq. Additions to the Fauna of the Olen*llu$-zone of
the North-west Highlands. (Plates XXIX.-XXXII.) 061
Raisin, Miss C. A., and Prof. T. G. Bonney. On the Relations of
some of the Older Frag mental Rocks in North-western Caer-
narvonshire 578
Koss, W. J. C, Esq. The Geology of Bathurst (New South Wales). 105
III* r ley, F., Esq. On the Sequence of Perlitic and Spherulitic Struc-
tures: a Rejoinder to Criticism. (Plate 1.) ... 10
— . On the Origin of Certain Xovaculite.s and ("juartzitea.
(Plate XIX.) '.177
Tball, J.J. II., Esq., and Sir A. Gf.iktb. On the Handed Structure
of some Tertiary Gabbros in the Isle of Skye. (Plates XXV 1.-
XXV1I1.) * 77 045
Thompson, Beeby, Esq. Landscape Marble 393
ri
TABLE OF CONTENTS.
Page
Walforp, E. A.. Esq. On some Bryozoa from the Inferior Oolite
of Shipton Oorge (Dorset). Part 11. (Plates 11.-1V.) . .TTTT 72
. On ( .'heilostonmtous Bryozoa from the Middle hi as.
(Plates V.-VJI.) 70
Watts, W. W., Esq. Note on the Occurrence of Perlitic Cracks in
Quartz. (Plate XVIH.) 307
Whitaker, W. W.„ Eyj., and A. J. Jukks-Brownr, Esq. On
])<•< p Boring? »t Cnlford and Wink ti el J , with Note* on those at
Wart* and ( 'lu'shunt 4*8
Woods, II., Esq. The Igneous Rocks of the Neighbourhood of
Builth ."360
PBQf'EEPINOS,
i. »4'
10
'9
List of Foreign Correspondents
List of Murchison Medallist*
List of Lyell Medallists
Applications of the Barlow-Jameson Fund
Alteration of Sect VI. Art 0 of the Bye-laws
Additions to the Library (with Bibliography)
TABLE OF CONTENTS. vii
Page
Alford C. J., Esq. On Auriferous Rocks from Mashonaland .... 8
Kdvards, D. T., Esq. Boring' on the Booysen Estate (Witwaters-
rand) 5
Johnbton-Latis, Prof. II. J. Enclosures of Quartz in Lava of
Stromboli, etc., and the Changes in Composition produced by
them %
Lvdkkkek, K.. Esq. On Argentine Fossil Vertebrates 146
Monckton, IT. W., Esq. On a Variety of Ammonites (Stq>hanocera»)
mfxtrmatu*, Young, fnmi the Upper Lias of Whitby 4.
Paukixsov, Jamks, Esq. Leigh Creek Jurassic Coal-Measures of
South Australia . 6
. Physical and Chemical Geology of the Interior of Australia 7
Sawyer, A. R., Esq. On Rock-specimens from Mashonaland .... 144
■
)igitized by Google
LIST OF THE FOSSILS DESCRIBED AND FIGURED
IN THIS VOLUME.
[In this List, those Fossils the names of which are printed in Roman typo
hare been previously described.]
Name of Species.
For hi lit ion •
Locality.
FoRAuiHirsfu.
Anumodiscus pleurotomarioidet. PI. ^
xxxiv. fig. 3 a, b, c
Bulimina polystropha. PI. xxxiv.
Gcr. 5
Ehrecbergina pupa. PI. xxxiv.
fig. 6 a, b .
r rcn dicularia britvformis. PI.
xxxiv. fig. 9 a, b
Haplophragmium neocomianum.
PL xxxiv. fig. 2 a, b
Laoena Meyeriana. PI. xxxiv.
tig. 7a, 6
Lingulina semiornata, var. creuea.
PL xxxiv. fig. 8 a, A
Patdlina antiqua. PL xxxiii. fig.
X 2 a f ^ •••••••••••••»•••••••••••••••«
Planispirina obscura. PI. xxxiv.
fig. la, b, c
Polymorph ina concura, var. denti-
marqinata. PI. xxxiv. fig- 14 a, 6
— Jrondiailarioidcs. PL xxxiv.
fig. 13 a, 6
rhabdogonioidu. PL xxxiv.
fig. 12 a. £
Trocluimmina squamata, var. /im-
6a/a. PL xxxiv. fig. 4 a, b, c ...
Truncatulina falcala. PL xxxiv.
fig. 15a, b, c ..,
Vaginulina ntocomiana. PL xxxiv,
figs. 10a, 6, 11 J
Littleton
Littleton, Hollo-
way Hill, etc.
Littleton
Littleton, Cbil-
worth, etc. ...
607
701
■
704
1709
695
706
1 708
- Bargate Beds \ Hollowoy Hill . 718
Littleton \
Littleton
I
717
716
U16
Littleton, Hollo-
way Hill, etc. 697
Hollo way Hill . 721
Littleton
711
Digitized by Google
Fossri,s dkscrturd and figured.
Namo of Specie*.
Formation. Locality.
Page
Entomostraca.
(O&racoda.)
Cythcrc rcticottata. PI. ix. fig. lO.f ? Lower Lias . .
vesiculosa. PI. xxxiii. fig. 1 a,
ft, c Bargate Beds ...
Wihoni. PI. ix. fig. 1 1 a, ft,c
, sp.? PI. ix. fig. 12
Cytheridea bicarinata, var. nodu-
'lose. PI. xxxiii. fig. 2«, ft, <? ...
bipapillata. PI. xxxiii. fig. 5 fl,
ft, r
ellipsoidea, PI. ix. fig. 6 a.
ft, r
fene»frata. PI. xxxiv. fig. 4 .
Moorei. PI. ix. figs. 7 o, ft. c,
8 <i, ft
iW/Zrata, PI. xxxiii. fig. 3 c,
b,c
Bargate Beds
?Bedminster ...j 166
Littleton ' 6S8
f 1G7
? Bristol
Littleton
i ?Westbury-on-
> i-iiaS i Severn
Bargate Beds . . . Littleton
_. . Beer Crowcotnbe &
KhatiC Long Itchington.
Bargate Beds ... Li ttleton
, sp. PI. ix. fig. 0
Ciftherftpferon Brodiei. PI. ix. I ? Lower Lias .. . ? Bristol
'fig. Mia, ft, c, d
costulifcrnm. PI. xxxiii
fig. 7 a, ft. c
ft.r
rcticulosum. PI. xxxiii. fig. 6 a,
IW7
690
691
164
690
165
690
J166
1 107
Bargate Beds . . . Littleton 692
Darwinula globosa, PI. ix. figa. 3,
4 a, ft
, var. sfricta. PI. ix. I
fig. f> j J
liassica. PI. ix. fig. 1 a, ft, c j
, var. major. PI. ix
Lias Linkefield 1
fig. 2
Rhatic Pylle Hill
163
164
162
163
Trilobita.
Oleuclfoide* armaius. PI. xxxii. ^
figs. 1-6
Olenellus giyas. Fig. 1, p. 667.
PL xxxii.'figs. 13, 14
intcrmrdius. PI. xxxii. fig. 7 .
— Lnpwortl.i. PI xxix fig, 1., ylowerCa,nbrinn
2, 2 a ; pi. xxx. fig. 7 ; pi. xxxii.;
fig. 8
, var . cfongatM. PI . xxi x
figs. 3-6
retiaiUiftis. PI. xxx. fig*. 1- 6,
8-14; pi. xxxi. fig*. 1-7 ... \)
(
Kenlocliewe ...
669
666
066
662
^665
Digitized by Google
FOSSILS DKSCRIBED AND FIGURED.
XI
>*aiue of Species. Formation. Locality. | Page
POLYZOA.
(CA-tW«/»i'<f.)
Citternifera clausa. PI. Tii. figs.
1-11
incongfdn*. PI. t. figs. 1-8,
1«. 17 - |
. forma prima. PI. t.|
fig9-9-13. ; • > Middle Lias
, forma secunda. PI. vi.
figs. 14-22
, forma ttrtia. PI. v.
figs. 18-21 ; pi. vi. figs. 1-4
-. forma quarta. PI. n
figs. 5-13
Perqentia vmpJurra/is. PI. ii.
figs. 5. 8; PI. in. figs. 21-24
gahata. PI. in. figs. 19.20.
25-33
jugota. PI. ii. fig". 9, 10:
PI. iv. figs. 0-13. 18-21
, Tar. bi-gibbom. PI. ii.
fig. 11 : PL iv.figV 14, 15
major. PI. ii. figs. 3, 4 ; PL lit.
figs. 11-13
minima. PI. ii. fig. 12 ; PL iii.
figs. 5-10
nidttlata. PL ii. figs. 1, 2;
PL iii. figH. 1. 2. 3. 4
porifera. PL ii. fig. 0 ; PL iv.
figs. 1-5, 10,17
- ■
Inferior Oolite
King'* Sutton ... S
Shipton Gorge
82
eo
80
81
82
t 82
[ n>,
70
70
| 76
i
74
73
. 75
LAUBI.LIBUAXCniAT.V.
(Asiphouida : IntegropalUalia.)
Anthracotnya nrenacea. PL xx.
figs. 4-0
elongata. PL xx. figs. 7-10
l«*i*. PL xx. fig. 12
ovalis. PI. xx. fig. 13
Carbonicola (Anthracosin)angulata.
PL xx. fig. 14
Naiadites carbonari us. PL xx
figs. 2, 3
VCoal Measures
(
440
440
441
South Joggina... { 441
441
1,440
Ami-hibia.
Bufo Tulgaris. Pi. x fig. 4... ' 1 Pk,i9tocene \ igbtUam i f
Rana temporana. PL x. figs. 1-3 j J * II
190
189
Rkitima.
Anguis fragilis. PL x. figs. 5-7 ...! 1
Vipera (Pelias) berus. PL x. I Pleistocene
figt.8, 9 J
Ighth
190
190
Digitized by Google
xii FOSSILS DESCRIBE!! AND FI6URKD.
Name of Specie*. Formation. Locality. | Page
Aves.
Alauda arrensia. PI. x. figs. 10-12
Anas bosons ? PI. x. figs. 16, 17...
Buteo ? PI. x. fig. 18
Larus ? Pi. x. fig. 15 I
Saxicola cenanthe ? Pl.x. figs. 13, 14 J
jpiei
Igbtham
f 191
| 191
i 191
| 192
1.191
.^orex
Mammalia.
( Insect ivora.)
pygmseus. Pi. xi. fig. 2 1 1
vulgaris*. PI. xi. fig. 1 | ;
Ightham ...
•K
192
192
{Cheiroptera.)
Vespertilio Nattereri. PI. xi. fig. 3| Pleistocene
Igbtham
.| 192
(Bodentia.)
Lutromys pusillus. PI. xi. fig. 6 ...
Lepua timidua. PI. xi. figs. 4, 5...
Microtus (= Arvicola) gregalis.
PL xi. fig. 12
( ) ratticeps. PL xi. fig. 1 1
Mus Abhotti. PL xi. fig. 8
Bylvaticus. PI. xi. fig. 7
Myodes lerarous. PL xi. fig. 9 ...
torquatu*. PL xi. fig. 10 ...
► Pleistocene
( Ungulata.)
Kangifer (= Cemis) tarandus.
PL xi. fig. 16
Khinoeeros antiquitatis. PL xi.
figs. 13-15
PUm
Ightbam
Ightham
194
193
197
\ 197
195
194
196
196
199
198
(Carnitvra.)
Canis lagopus. PL xii. figs. 5-9 ... ^
vulpes. PL xii. figs. 1-4
Hvama crocuta ? PL xii. fig. 11...
Muttda robtuta. PL xi. fig*. 17, 18 J- Pleistocene
vulgaris, var. minuta. PI. xi.
figs. 19, 20
Ursusarctos? PL xii. fig. 10 .
J
Ightham
I f202
i 201
! | 201
.^200
! 201
I 1201
Digitized by Google
EXPLANATION OF THE PLATES.
Plat* Paoh
. f Perutic and Spheruutic Strictures, Uj illustrate Mr. F.
• \ Rutley's paper on those structures 10
IT IV i IJtFKK,OR OoWTE Bktozoa, to illustrate Mr. E. A. Walford's
^ paper on those fossils from Shiptun Gorge, Dorset 72
V. ( Liassic and Oolitic Bryozoa, and
VI.- VII. -1 Liassic Ukyozoa, to illustrate Air. E. A. Walford's paper on
[ Cheilostouiatous Bryozoa from the Middle Lias 7'J
( Geological Map op a Portion op South-eastern Matto
VIII. s Grosso, to illustrate Dr. J. W. Evans's paper on the geo-
( logy of that province 8f>
f Riletic and Liassic Ostkacoda, to illustrate Prof. T. Rupert
\ Jones's paper on those fossils in Britain 150
X. Amphibia. Reptiles, and Bird* prom Ightiiam,
XI f Shrews, Bat, Rodents, Ungulates, and Carmvors from
\ Ightiiam,
1 Cak.mvora puom Ightiiam, to illustrate Mr. E. T. Newton's
XI . { paper on the Vertebrate Fauna collected from the Fissure
1 near that locality 188
Banded Gabbro in Tertiary Volcanic Seeie9, uidqk north
op Driuh an Eidhne, Glen Sugachan, Skye, and Dyke
OF GrANoi HYRE INTERSECTING THE GaUBROS, to illustrate
XIV. * Sir Archibald Geikic's paper on the Relations of the Basic
and Acid Rocks of the Tertiary Volcanic Series of the
Inner Hebrides 212
f Microscopic sections of Gneisses, Ai-lite*. and Contact-
YV ' Rocks, to illustrate Dr. J. \V. Gregory's paper ou the
j Waldensian Gneisses and their Place in the Cottian So-
[ quence 232
f Sketch-map of Part or the Carrock Fell District, snow-
XVI. - J ing variation op Gabbuo, and luicroscopio sections of
XVII. I Carrock Fell Gabbuo, to illustrate Mr. Alfred Harker s
[ paper on that rock 311
(Microscopic sections of Perlitic Phtchstoke from oanhy
Braes, to illustrate Mr. W. W. Watta's paper on the
Occurrence of Perlitio Cracks in Quartz 307
Digitized by Google
XIV KXl'LA NATION OF THE l'LATRS.
Flats Page
Microscopic sections of Novaculitks, Quabtzites, and Dolo-
mites, to illustrate Mr. P. Kutley's paper on the origin of
the two former rocks 377
1
XX.
Coal-Measure Shells from tue South Joggiks, to illustrate
Sir J. W. Dawson's paper and Dr. Wheelton Hind's ap-
pendix on the genus XiaiaHitea, as oocurring in the Coal-
formation of Nova Sootia 435
( Geological Map or the Libyan Desert, to illustrate Cant.
H. G. Lyons' s paper on the Stratigraphy and Physiography
of that Area '.".Ml
XXII. f Diagrammatic Sections of the Drakenboerg and the Higii-
I Veld Plateau, ajid from Moxt-aux-Sourcrs, Dhakens-
I berg, to St. Lucla Bay ;
XXIII. -j Section from Hartebeest-Foxteix (Transvaal) to Vrede-
fort (Orange Free Statk), to illustrate Mr. D. Drapers
papers on the Geology of South-eastern Africa and on the
^ Occurrence of Dolomite in South Africa "... 548, 561
XXIV-
XXV.
Carboniferous Doi.erites and Tuffs from Derbyshire, to
illustrate Mr. II. H. Arnold-Bcinroees paper on tbe micro-
scopical structure of those rocks 003
XXVI. /"Folded and Banded Gabbko at Drum an Eidiixe, Sktr,
XXVII. Granulitic and Foliated Gabbuo, traversed bv later veins
J of Felspathic Gabuho, and
XXVIII. j Microscopical sections of Banded Oabdro of Skye, to illus-
trate Sir Archibald Geikio and Mr. J. J. H. Trail's paper
\ on those recks 045
XXIX f Olenellus, Olenelloides, Mesoxacis. and Holmia, to illus-
vvyti ~\ tr, te Mr. B. N. Peach's paper on the Fauna of tbe Ole-
I nellus-zone in the North-west Highlands 061
XXX TIT - f Margate Ostracoda, Foramini fera, etc., to illustrate Mr. F.
XXXIV I Chapman's paper on tbe Bargutc Beds of Surrey and their
( Microscopic Contents 077
XXXV. - f Coxe-in-Cone, to illustrate Mr. \Y. S. Gresley's paj>cr ou
XXXVI. \ that structure 731
Digitized by Google
WOODCUTS AND OTHER ILLUSTRATIVE FIGURES
BESIDES THOSE IN THE PLATES.
WE
TIO. l'ACK
Map of the Chriatiania Region Hi
Sketch-map of Grau (Chriatiania District) 17
Diagram-section on the Bamtou Railway in Barnton Park 39
Geological Sketch-map of tlie Vale of Wardour 47
1. Beds seen in Wockley Quarry 50
f Diagram showing variations in strata between the Cinder-bed
*"* \ and the ^rc^tft>«/V/w-liiueetone 57
3. Section along the railway, west of Dinton Station 60
4. Diagram showing the vertical succession of the Purbeck Beds . f>4
, f Generalized section from the Hills of Tnpirapuam to the Allu-
1 vial Tract aouth of Cuyabu 89
0 / Portion of section on W. bank of Rio Paraguay, B.irra dos
"t Bugres 94
Geological Sketch-map of Bathurst (N. S. W.) 108
Section across the District of Bathurst (N\ S.W.) 109
Map showing the extension of the Gosau Beds in Gosauthal
and Russbachthal 120
Diagrammatic section from the Thames Valley, below Maiden-
head, to Haslemere 154
I. 8ection from Cotman's Ash to Shingle Hill 174
„ f 8ection acrosa the Shodc at Plaxtol, from Shingle Hill to Hurst
Zm\ Wood 174
Digitized by Google
Xvi WOODCUTS AND OTHER ILLUSTRATIVE FIQCBK8.
no. PAGE
o f Section from near Cotraan's Ash along the Valley of the Shode
**• \ to Plaxtol 175
4. View of the Fissures near Ightham 178
5. Generalized section along one of the Azures 179
6. Plan of one of the keyed Blocks, seen from above 181
, f Flan of portion of ridge north of Druim an Eidhne, south of
' \ Glen Sligachan, Skye 222
2. Plan of granophyric dyke, Druim an Eidhne, Skye 225
3. View of felsitic dyke, north of Druim an Eidhne, Skye 22<>
a f Plan of quartz-felsite dyke and veins traversing gabbro, west
' 1 of Druim an Eidhne, Skye 227
. / Sketch-map illustrating the distribution of the Waldensian
l' 1 Gneisses 2:i8
2. Reproduction of part of Gastuldi's map of the Paradiso 240
3. Inclusion of ' pietre verdi' in gneiss of Vonzo Valley 242
« < Sketch-map showing distribution of Waldensian Gneisses in the
*' 1 Pussoleno District 240
r / Section from Foresto di Susa across and up the Gerrardo
°- 1 Valley 248
„ {Junction of gneiss and limestone in a gully north of Col de
b' < Vento 249
„ f Gneiss, with included fragments of 'pietre verdi' series, at
'•\ Mustione 250
8. Sketch-map of the gneiss-exposures round Gol de Vento 251
9. Veins of gneiss (aplite) in * pietre verdi ' series. Angrogna Valley. 257
1. Schistose dyke by the path to the Grum Alp 279
0 / Section cut from middle part of second dyke by the path to the
2-\ Grum Alp 281
1. Section at Altkirche 288
2. Section at back of the village of Realp 293
3. Section at the top of the Furka Pass 295
1. Section on north side of the Valley of R. Clos des Morts 305
0 f Crumpled Clos des Morts Limestones carried by thrust-plane
*" \ on to uncontorted dolomite 30;>
Map of the Monte Chaberton Area 309
3. Section through Monte Chaberton 310
Digitized by Google
WOODCUTS AND OTHER ILLUSTRATIVE FIGURB8. XVII
via. PAQB
Diagrammatic section across Carrock Fell 314
Sketch-map of Sourton Tors 389
1. Specimen of metamorphosed tuff showing * corduroy structure'. 352
2. Metamorphosed ash on the flank of Coek's Tor 357
.i. Hornblende-schist, Lizard 357
1-0. Perlitic cracks in quartz 371
I -J. Auriferous quartzite from Nondweni, ZuluJand 388,389
1 2. Landscape Marble 395, 397
1. Protocaris »V<wAi, Walcott 413
2. Head-shield of Microdwu* Meeki 414
.'{. Youngest stage of Olendlua a.saphoiden 415
4 5. OUnellus astiphuides 4 Hi
0. Sao hir*u(a 417
- i Diagram allowing probable composition of head-shield [of
'• I Trilobite] ... 418
V Diagram of eye of Apus 421
9. Head-shield of OUnellus (A/esouaci*) aeaphoides 423
10. Pygidium of Calynvene Blumenbachii 424
1 1. Specimen of Triarthru* Iicekii showing an ten me 425
12. Limb of Triarthru* Bcckii 420
,, ,1 (Sections through Caltpnene tsenaria and Apus (Lepidurus)
l* 1 rpitziKTgenti* 427
15 10. Do. do. do. do 428
17. Enrolled Caltpnene 428
Map of Romford District 444
Section in Romford Cutting, south of Victoria Road Bridge ... 445
1. Plan showing sewer-cutting in Thames Valley at Twickenham. 453
2. Section of do. do. do. 455
3. Sections of sump-holes in the gravels at Twickenham 450
1. View of Central Peak of Mount Kenya 51 H
2. Map of S.W. slopes of Central Summit of Mount Kenya 517
3. Section through Mount and Lake Hohnel 519
vol. L. b
Digitized by Google
1
Will WOODCUTS AXD OTHER ILLUSTRATIVE F1GCRK3.
nr.. pack
4. Terminal Moraine of the Lewis Glacier ... 52'-'
a. Isobar ic Mup, showing low-pressure area in Equatoriul Africa. 520
Geological Sketch-runp of neighbourhood of Builth 5<>8
1. Section south of Tan-v-graig 572
2. Section seen in road-cutting at bark of Peu-cerig House 57a
! . Diagrammatic section nlong railway, west side of Llyn Padarn. 583
2. Section alo::g Mute-railway, east of Llyn Padam f>!H »
/ The alleged unconformitv, by slate-railwav east side of Llvn
* { Padarn ! "... 592
4. Sketch-map of part of Llyn Padarn ;jW
*». Section across Moel Goronwy 507
1. (Jleurllm (/if/a*, sp. nov 007
2. Telson of Olcnetlus and Meimuci* 073
, f Section of siliceous rock with sponge-apicules, etc. (Bargate
1 nerie*) OS2
2. Section of Bargate Limestone 084
3. Section of Neocomian Limestone from the Richmond Boring . »W»
Section through a cone-in-cune bearing nodule... 734
CORRIGENDA.
Proi . page 7. line 0 from top, for ' South' read 4 North.'
Pro?, page 13, line la from top, /or ' la 1 7 ' read 4 113 1 7.'
Page 85, Hue 11 from bottom, for 4 in* the year 1842' n-ad 4 about the year
1831.'
Page 81) (section), Rizama should be to the left, not to the right of the two-
ridged hill.
Page 103, line 11 from top, for 4 hone like ' read 'bone-liko.'
Page 103 ( Explanation of PI. VIII.), for ' Ciripuru' read 4 Ciripiru.'
Piute VIII. In the scale of kilometres. /or 4 10, 20. 30 ' raid ' 20, 40, 00.'
Plate VIII. In the key-map of S. America, the highlands of Brazil an1 erroneously
represented as consisting of mountain-ranges, whereas they are for tin*
most part gently-undulating table-lands intersected by deep river-
valleys.
Page 1 10, line 18 from top, for • Suraua' read • Tarana.'
Page 117, line 3 from top, /or ' microscopic' read * macroscopic.'
Page 173, line 3 from top, for 4 lime' read 4 carbonate of lime.*
Page 201, note line I, for 4 seciton ' read 4 section.'
Digitized by LjOOtfle
THE
• *
QUARTERLY JOURNAL >
op *.
THE GEOLOGICAL SOCIETY OF LONDON.
J * " -
Vol. L.
1. NOTES <Wl <fo OCCURRENCE of M A M VOTE - REM A INS in the YUKOX
District of Cakada and in Alaska. By George M. Dawson,
C.M.G., LL.D., F.R.S., F.G.S., Assistant Director of the Geolo-
gical Surrey of Canada. (Read November 8th, 1893.)
These notes, relating primarily to the occurrence of remains of the
Mammoth in the geographical valley of the Yukon River, are the
result of a correspondence between Mr. H. Moody of the Canadian
Pacific Railway Co., the Assistant Secretary of the Geological
Society, and the writer, respecting statements which had reached
Mr. Moody from a friend resident in the extreme north-western
part of the Dominion of Canada. It has been suggested that a
brief notice of the facts in this connexion, so far as these are
known, may be of some interest to the Geological Society.
The original discovery of bones of the Mammoth in the Yukon
region is due to Mr. Robert Campbell, an officer in the service of
the Hudson's Bay Company, who between 1840 and 1852 travelled
through and established trading-posts in the upper valley of the
Yukon, and was the first white man to penetrate this reraoto part
of North America.
In a brief account of his explorations, printed at Winnipeg in
1885, Campbell writes:— " I saw the bones, heads, and horns of
Buffaloes [Musk-Oxeu ?] ; but this animal had become extinct before
our visit, as had also some species of Elephant, whose remains were
found in various swamps. I forwarded an Elephant's thigh-bone
to the British Museum, where it may still be seen 'V
1 ' The Discovery and Exploration of the Yukon (Pelly) River,' Winnipeg,
1885.
Q. J. G. 8. No. 197. b
Digitized by Google
2 % BJ?. G. M. DAWSON ON M Ail MOTH-REX A INS [Feb. 1894,
*• *• *»
As CarajJbVlTs posts on the Upper Yukon were finally abandoned
in 1852, £he bone thus referred to bv him must have beeu sent out
beforer.thjs date. It was a tibia, not a thigh-bone, and was de-
scribed .by Sir John Kichardson in 1855 as referable to Elephns
prinijAtnius. Richardson states that it was identical in form with,
though larger than, a corresponding bone of the same animal bronght
* • Jmck by Capt. Beechey from Eschscholtz Bay. The skeleton of which
informed part was said to be complete when found ; but most of the
/•"'•bones were lost by the Indians who extracted them for Campbell.
• According to a statement subsequently obtained from Campbell,
*-*,'• these bones were found at some place not far from the former site
V.* of Fort Selkirk, at the confiuence of the Lewes and Pelly Rivers.1
Br. W. H. Dall in 1866-67, during his connexion with the
. '•*.* "Western Union Telegraph Expedition (abandoned on the completion
• ' of the Atlantic Cable), visited a number of places in the lower
valley of the Yukon, within what is now the Territory of Alaska.
In the volume which resulted from his explorations, and in other
publications, ho frequently mentions the occurrence of Mammoth -
remains in this region, writing in one place as follows : —
"Wild and exaggerated stories have found a place, even in
official documents, in regard to fossil ivory. This is not uncommon
in many parts of the valley of the Yukon and Kuskoquim. It is
usually found on the surface, not buried as in Siberia, and all that
I have seen has been so much injured by the weather that it was
of little commercial value. It is usually blackened, split, and so
fragile as to break readily to pieces. A lake near Nushergak, the
Inglutalik River, and the Kotlo River are noted localities for this
ivory V
In 1886 the Geological Survey of Canada acquired from Mr. F.
Mercier, who had 6pent many years as a trader in the Yukon
region, a number of bones, tusks, and teeth of the Mammoth.
These were chiefly obtained by Mr. Mercier near the mouth of the
Tanana River, one of the main feeders of the Yukon on the south
side. Mr. J. F. Whiteaves, F.G.S., Palaeontologist to the Geological
Survey of Canada, has kindly furnished the subjoined note on these
remains : —
" In my judgment all the Elephantine remains collected by
Mr. Mercier in the Yukon region, and now in our Museum, are
clearly Elephas (sub- genus Euelephas) and not Mastodon,
" Four of the specimens collected by Mr. Mercier are perfect
molars, essentially similar to those from Burlington Heights, near
Hamilton, Ontario, which E. Billings referred to Ehphas Jacksoni
of Briggs and Foster, but which Dr. Falconer subsequently iden-
tified with E. primigeniusy Blumenbach.
*< The specific relations of the North American fossil Elephants
» ' Zoology of the Voyage of H.M.S. « Herald," (1854) p. 142 ; Am. Journ.
Sci. uer. 2, vol. xix. (lSbb) p. 132; Annual Report, Gcol. Surv. Canada, 1887,
41 B
' a • Alaska and its Resources,' 1870, pp. 238, 400, 479 ; Am. Journ. Sci.
ser. 2, vol. xlv. (1808) p. 99.
Digitized by Google
Vol. 50.]
I2f CANADA AND ALASKA,
(as distinguished from Mastodons) are treated of at considerable
length in vol. ii. pp. 234-238 of the ' Pala?ontological Memoirs and
Notes of the late Dr. Hugh Falconer,' uoder the heading 4 Synonymy
of American Fossil Elephants.'
»* It is there stated that there are but two species of fossil
Elephant in North America. The first of these is the Ehpluis
(Euelephas) primigcnius, Blumenbach, of which E. Jacksoni, of
Briggs and Foster, and E. aniericttnugy Leidy, are synonyms. Ac-
cording to Dr. Falconer, all the specimens from the Yukon, Alaska,
and Burlington Heights are E. primigenius. The second species is
E. Colunibi, Falconer, of the southern part of the United States and
Mexico."
The writer, in 1887, carried out an extended reconnaissance-
survey in the Yukon District, in the valleys of the Polly and Lewes
branches of the main stream, but not going below the confluence of
these two rivers.1 In the whole region thus traversed no Mammoth-
remains were met with, nor was their presence reported by such of
the gold-miners as had worked in parts of these valleys ; though
some of the same men had frequently noted Mammoth-bones farther
down the Yukon valley, particularly in the vicinity of Forty-Mile
Creek, where rather important placer-mining has been carried on.
The above notes refer particularly to the occurrence of Mammoth-
remains in the inland region of Alaska, and in parts of the adja-
cent Yukon District of the North-west Territory of Canada — the
International boundary following the 141st meridian. The existence
of similar remains, as well as those of other animals not now in-
habiting the region, has long been known at various places on the
coast, both to the south and north of Bering Straits. The most
notable and the first discovered of these localities is Kotzcbue Sound,
where bones were collected by Kotzebue in 1810, Capt. Beechey, of
H.M.S. 4 Blossom,' in 1826, Capt. Kcilett, of H.M.S. « Herald,' in
1848, Dr. W. II. Dall in 1880, and Mr. Nelson in 1881. The
specimens brought back by tho three first-named expeditions were
described by Eschscholtz, Buckland, Forbes, and Kichardson in
appendices or auxiliary works to tho narratives of the several
voyages.
X U has recently given a summary of what is known respecting
these localities, with full references to the published accounts of
them.3 The bones found at Kotzebue Sound and at other places on
the coast aro associated with what he calls tho 4 ground-ice for-
mation.' The localities are indicated in a general manner on the
map accompanying Dall's work ; but, so far as these are described
or the writer is aware, no information exists to show that sut h
bones are associated with 4 ground-ice ' anywhere south of Kotzebuo
Sound.
The following list of species obtained in Kotzebue Sound is given
1 Annual Report, Geo]. Surv. CnnnHn, 1887-88. Part B.
2 Bull. U.S. Gool. Survey, no. 84, ltfttt, pp. 20U-207.
Ji 2
Digitized by Google
4
DR. G. M. DAWSON ON 31 AM MOTIf-RKM AIN8
[Feb. 1894,
by Dull, chiefly from Richardson's report, but with revised nomen-
clature 1 : —
Eiephas primigeniM, Blumenbaeh.
Klephas Columhi, Fulconer [?].a
Equits major, De Kay.
Aires americanm, Jardine = Machlis, Ogilby.
Iiatufi/er Carfrou, Baird.
Gvihos uiowhatm, Blainville.
Ovihos muximus, Richardson = 0. cavifrons, Leitly.
Bison craisicorui'js, Richardson = B. anti'/uut, Leidy.
No Ufastodon-honcs appear to have been found in any portion of
the extreme north-west of North Amorica.
Of particular interest in connexion with the general question of
the distribution of Mammoth-remains in the Alaskan region is the
occurrence of such remains (a tooth) on St. George Island of the
Pribilof group, in Bering Sea, and on Unalashka Island of the
Aleutian Chain.3 Mr. J. Stanley-Brown further notes the discovery
of a Mammoth-tusk on St. Paul Island of the Pribilof group, but
appears at the same time to throw doubt on the means by which
these remains reached the Pribilof Islands, writing—" As there is
not a foot of earth uj>on either island, save that which has resulted
from the decomposition of the native rock and the decay of
vegetation, the value of such testimony is questionable." *
The precise intention of the cautionary remark just quoted is not
clear to the writer. The finding of the bones upon St. George and
St. Paul Islands does not appear to be doubtful. Both islands
were uninhabited previous to their discover}' by the Russians ; they
show neither traces of glacial action nor erratics ; and in what
way the Mammoth can be supposed to have reached these islands,
except by means of a former connexion with the raainlaud, it is
difficult to understand. We have, moreover, the Mammoth-bones
already mentioned on Unalashka Island, vouched for by Dr. Stein,
and a like explanation must be found for all these cases. This
does not appear to be difficult, for the whole eastern part of Bering
Sea is rather notablv shallow, nearlv everywhere less than 50
fathoms in depth. An olevation of the land by about 300 feet
would thus suffice to unite the islands mentioned, with a number of
others, to the American Continent, and it appears scarcely to admit
of doubt that it was across such a practicable plain that the
Mammoth found its way to these places.
The most important observation to be based on the foregoing
notes is that the remains of the Mammoth, with those of other
associated animals, are, in the north-western part of the North
American Continent, abundant in, if not strictly eonfined to the
1 Oj>. cit. p. 204.
2 I have ventured to place a mark of interrogation against this epeeies, for
Falconer gives it» range as being from Mexico to Georgia and perb»i|w farther
south. See ' Paheontological Memoirs and Notes,' vol. ii. pp. 230-231. See
also Howorth, 'The Mammoth and the Flood,' pp. 274-276.
3 Bull. U.S. Geol. Survev. no. 84, p. 2W.
* Bull. Geol. Soc. Am. vol. iii. (1892) p. 499.
Digitized by Google
Vol. 50.]
1$ CANADA AND ALASKA.
5
limits of, a groat unglaciated area there existing. "With the exception
of the southern mouutainous sea-margin of Alaska, and doubtless
also that of certain local inland ranges, this unglaciated area may
be described as comprising nearly the whole of Alaska, together
with a considerable portion of the adjacent Yukon District of
Canada.
As the result of his explorations in this part of the continent,
the writer has been able to determine the fact that during the
glacial period the Itoeky Mountain or Cordilleran region, from
about the 48th to the 0i3rd degree of latitude North, was at one
time buried beneath a great confluent ice-mass some 1200 miles in
greatest length in a north-west by south-east bearing, with an
average width of about 400 miles.1
This Greenland-like ice-cap was distinct from the still greater
Laurentidc Glacier of Eastern North America, and, because of tho
trend of the mouutain-ranges which it covered, it moved principally
in two directions — south-eastward and north-westward. Tho
south-easterly motion of one part of this ice-mass the writer had
demonstrated in 1877, a but it was not till lb87, and then as a
result of the Yukon expedition, that he was enabled to ascertain
the north-westerly movement of its northern part, and to show
that there was a definite limit to its extent in both directions.
Being thus clearly distinct from any extension of polar ice, as well
as from the great Laurentide ice-mass, it became appropriate to
designate it as the Cordilleran Glacier.3 Further evidence respecting
the northern limit of glaciation in this region has since been
obtained by Mr. K. G. McConnell, of the Canadian Geological Survey
(1 888), Mr. I.C. Russell, of the U. S. Geological Survey (1889), and
Mr. C. W. Ilayes, of the same Survey ( 1 89 1 ).* The area covered
by, and the directions of movement of, the Cordilleran ice-mass have
been approximately mapped in one of the papers above referred to,J
and the later observations of the above-named gcntlomen have not
in any material degreo changed the indications there given.
Within the area which was covered by the great Cordilleran
Glacier, remaius of tho Mammoth are either entirely wanting or
arc very scarce. The reported finding of a tooth on the southern
part of Vancouver Island, and that of a portion of a large bone
(which, though not determinable, may have belonged to Buch an
animal) in gravels worked for gold on Cherry Creek,6 are the only
possible exceptions known to the writer, and tho deposits from
which the last-mentioned bone was obtained may be of pre-Glacial
age.
1 'On the later Pbysiographical Geology of the Rocky Mountain Region in
Canada,' Trans. Royal Soc. Canada, vol. viii. (18'JU) sect. iv. p. 27.
2 Report of Pi-ogres*, Geol. Surv.Cannda, 1877-78, pp. 130 B, lfil B ; Quart.
Jouro. Geol Soc. vol. xxxiv. (1878) p. 1 19, vol. ixxvii. (1881) p. 283.
3 'American Geologist,' vol. vi. (1890) p. 162.
* Annual Report, Geol. Surv. Canada, 1888-89, p. 28 D ; BulL Geol. 80c.
Am. vol. L (1890) p. 144; National Geogr. Mag., Washington, vol. iv. p. 157.
J Trana. Royal 80c. Canada, op. cit. pi. ii. map no. 4.
• Okanagan District, British Columbia.
Digitized by Google
DR. 0. M. DAWSON ON MAMMOTH-REMAINS [Feb. 1 894,
The likeness of the non-glaciated north-western portion of
North America, with its abundant Mammoth-remains, to the
similarly characterized northern part of Asia has already beeu
recognized. Tho purport of the foregoing remarks is to indicate
the existence of a south-eastern boundary to the Mammoth-inhabited
portion of Alaska and the Yukon District; nor can it be reasonably
doubted that the North American and Asiatic land was continuous
Qt the time of the existence of the Mammoth, or for some portion
of that time ; for an elevation of the land sufficient to enable the
Mammoth to reach the islands in Bering Sea, already refcrrod to,
would result in the obliteration of Bering Straits.
Many conjectures have been advanced as to the mode of occurrence
and origination of the lgrourid-ice formation,' in association with
which the bones of the Mammoth and other animals arc found along
the northern coasts of Alaska. Dall summarizes these in his work
previously cited,1 and it may now be confidently assumed that the
descriptions of Kotzcbue and his party, of Capt. Kellett and others
on the 4 Herald,' of Dall and Lieut. Cant well," correctly indicate the
facts of the case. The clearest descriptions of the phenomena are
those of Scemann and Dall.3 From these it appears that the lower
parts of cliffs which have some extent on Kotzcbue Sound are
composed of solid ice, somewhat discoloured and impure, and showing
indications of stratification. Above this ice rests a layer of clay,
in which the bones occur, and capping tho whole is a peaty layer
supporting the vegetation of the region. It is further apparent that
this or a very similar formation occurs at a number of points along
the northern coast of Alaska, but nothing has been adduced to show
that it is absolutely continuous over any great area; — there is, in
fact, some reason to believe that it is confined to limited tracts, even
in tho vicinity of Kotzcbue Sound.4
In the present connexion, the * ground-ice formation ' is of interest
only in bo far as its existence and tho mode of its origination
may throw light on the date and method of entombment of the
Mammoth-remains associated with it. With respect to the origin of
the deposits, the writer ventures to offer the following suggestions.
The country in which the ' ground-ice formation ' occurs is low
in its relief, and tho formation occupies its lower tracts. The ice
itself must undoubtedly have been produced upon a land-surface,
and since the time of its production this surface can never have
l>ecn covered by the sea ; for this would inevitably have reduced the
frozen condition of the overlying clays, and have resulted in the
destruction of the icy sub-stratum as well.
With an elevation of the land by an amount of 300 feet or more
(such as appears to be required by the Mammoth-remains on islands
already mentioned) tho warmer waters connecting with the Pacific
1 Bull. U.S. Geol. SurTev, No. 84. pp. 260-264.
3 ' American Geologist.' rol. ti. (1890) p. 51.
3 « Voyage of H.M.8. « Herald,' ' voL ii. pp. 33 et *eqq. ■ Bull. U.S. Geol. Surv.
No. 84, pp. 261 et seqq.
* ' American Geologist,' voL vi. (1SW) p. 52.
Digitized by Google
Vol. 50.]
IN CANADA. AND ALASKA.
7
would be confined to the deeper western portion of what is now
Bering Sea, forming there a limited gulf, without outlet to tho north,
from which the region where the * ground-ice formation ' is now
found would be so far removed as to greatly reduce its mean annual
temperature. Snow falling upon this nearly level, northern land,
and only in part removed during tho summer, would naturally tend
to accumulate in nevee-like masses in the valleys and lower tracts,
and the underlying layers of such accumulations would pass into
the condition of ice, though without the necessary slope or head to
produce moving glaciers. The evidonco does not seem to imply that
the Mammoth resorted to this extreme northern portion of the
region during the actual time of ice-accumulation, but this animal
may be supposed to havo passed between Asia and America along
the southern parts of the wide land-bridge then existing.
At a later date, when the land became depressed to about its
present level, Bering Sea extended itself far to the eastward, and
Bering Straits were opened. Tho perennial accumulation of snow
upon the lowlands ceased, and in the southern parts of Alaska such
masses as had been formed may havo been entirely removed.
Partner to the north and at a greater distance from tho Pacific
waters, while the total precipitation would probably bo increased,
a greater proportion would fall as rain, and floods resulting from
this and the melting of snow on the higher tracts would bo
frequent. Thus it may be supposed that deposits of clay and soil
from adjacent highlands and from tho overflow of rivers covered
large parts of the remaining ice of the lowlands, and that wherever
ao covered it has since remained ; tho winter temperature being
still sufficiently low to ensure the persistence of a laver of frozen
V A V
soil between the surface annually thawed and the subjacent ice.
Over the new land thus formed the Mammoth and associated animals
appear to have roamed and fed, and wherever local areas of decay
of the ice may have arisen, bottomless bogs and sink-holes must
have been produced which served as veritable traps.
It will be observed that this hypothesis requires a rather abrupt
passage from tho conditions under which the ice accumulated to
those in which, before it had time to disappear, it began to be covered
up by soil, but the change may nevertheless have extended over a
considerable number of years. The association of the Mammoth
with an animal so essentially Arctic as tho Musk-Ox requires — as
has frequently been pointed out — the admission that the Mammoth
was capable of living in a rigorous climate, though it may be that the
southern limit of the migration-range of ono animal merely over-
lapped the northern limit of tho migration-range of tho other.
The occurrence of the Moose (Alces amtricanus) implies the existence
at that time of woodland, or at least of well-grown thickets.
In the Cordilleran region generally, the Pliocene and Glacial
periods were characterized by several important changes in elevation
and depression of land ; 1 but it is unsafe to assume that these
1 Trana. Royal Soc. Canada, vol. viii. (1800) sect. it. p. 54; Bull. U.S. Geol.
Survey, uo. 84, p. 278.
Digitized by Google
8
DR. 0. M. DAWSON OK MAMMOTH -REMAINS [Feb. 1 894,
chauges equally affected the northern region here particularly treated
of ; for it is not only very distant from the localities which have so
far been specially studied, but the physical features of the Cordilleran
belt become diffuse and ill-marked to the north, and such mountain*
ridges as remain assume new trends. It may, however, be taken
for granted that this Tegion shared to some extent in these great
movements of elevation and depression, and as the Very existence of
the ' ground-ice ' shows that the area where it is found has not
since the date of its formation been materially lower than at present,
it may reasonably be argued that it dates from a period approaching
the conclusion of the series of changes in level, or subsequent to the
last well-marked epoch of depression of the land.
Thus, without entering into any details respecting the sequence
of these great earth-movements in the Cordilleran region of British
Columbia,1 it may be stated as probable that the uprising of tho
land which led to the accumulation of the 'ground-ice' was co-
incident with the second (and latest) epoch of maximum glaciation,
which waa followed by an important subsidence in British Columbia.
Discussion.
Tho President said that many interesting points had been brought
forward by the Author. The differentiation of the glaciated from
the unglaciated area, and the clear recognition of a north-western
as well as a south-eastern boundary to the Cordilleran ice-mass,
struck him as being of great importance
Sir Henry Howorth remarked upon the long and careful survey
of N.W. America which has been made by the Author, and upon
tho value of the conclusions to which he has come : firstly, in regard
to the absence of ancient glaciation in Alaska and its borders ;
secondly, in regard to the existence of a great glacier in the
Cordilleras, whose products are quite independent of and have
nothing to do with the Laurent ian drift ; and thirdly, in regard to
the distribution of tho Mammoth. It was a new fact to him, and
one of great importance, that Mammoth-remains had occurred in
Unalashka and the Pribilof Islands in Bering Sea, proving that
in the Mammoth age there was a land-bridge here, as many
inquirers had argued. It would bo very interesting to have the
western frontier defined, where the Mammoth-remains cease to be
found. It would also be very interesting to know how far south on
the west of the Cordilleras tho true Mammoth, as distinguished from
Elepha* Columbia has occurred.
llegarding one conclusion of Dr. Dawson's, the speaker could not
agree with his friend, namely, about tho age of the strata of ice
sometimes found under the Mammoth-beds in Alaska as they have
been found in Siberia. The speaker was of opinion that this ice has
accumulated since the beds were laid down, and was not there when
the Mammoth roamed about in the forests where he and his com-
1 For a discussion of which see Trans. Royal Soc. Oanada, vol. viii. (1890 )
sect. ir. pp. 40-55.
Digitized by Google
Vol. 50.]
IS CANADA AXD ALASKA
it
panions lived. Humus and soil cannot accumulate upon ice except
as a moraine, and there are no traces of moraines or of gre:it
surfacc-glaciation in Alaska and Siberia. Nor could either tho
flora or fauna of the Mammoth age havo survived conditions con-
sistent with the accumulation of these bedB of ice almost immediately
below the surface, or consistent with their presence there. The
speaker considered that these beds are due to the filtration of water
in the summer down to the point where there is a stratum of frozen
soil, through which it cannot pass and where it consequently accu-
mulates, freezes, raises the ground, and in the next season grows
by the same process until a thick bed of ice has been formed.
The evidence goes to show that tho present is tho coldest period
known in recent geological times in Siberia and Alaska, and that the
period of the Mammoth and its companions was followed and not
preceded by an Arctic elimate where its remains occur.
Dr. Hesry Woodward mentioned that in I80O Capt. Kellett and
Lieut. Wood brought remains of Musk-Ox and Mammoth to tho
British Museum from Kotzebuc Sound, Alaska ; and in 1873 tho
Kev. R. McDonald (one of the Hudson's Bay Company's Chaplains)
from Fort McPherson, Mackenzie River, Arctic America, gave to the
National Collection, from tho Porcupine Hivcr, remains of Mummoth,
Mus»k-Ox, Bison prisewt, and Horse. The Mastodon has lately been
found in Kent County, Ontario. Canada. These instances prove the
former abundance of the land Mammalia in high latitudes in North
America. The most interesting point in Dr. Dawson's paper is the
mention by him of the remains of Mammoth on the Aleutian
Islands, proving that this was the old high road for this and other
mammals from Asia into North America in Pleistocene times.
Prof. Hull observed that, with reference to the requirements of
the large animals referred to in Dr. Dawson's interesting paper, ho
had seen it stated that one had been discovered in N.W. America
nearly entire, and in its stomach were about seven bushels of
vegetable mntter. However that might be, it seemed clear that the
climate of tho circumpolar regions had undergone a great change
since the Mammoth had become extinct; in consequence of which
the vegetatiou had materially fallen off. Ho also desired to call
attention to the clear evidence which tho Author's paper afforded of
the former wider extension of land in the Arctic regions during
the Mammoth period.
Digitized by Google
10 MB. P. BUT LET ON THE SEQUENCE OF [Feb. 1894,
2. On the Sequence of Perlitic and Sphebulttic Stbuctubes : a
Rejoinder to Criticism. By Fbank Rutlet, Esq., F.G.S.,
Lecturer on Mineralogy in the Royal College of Science,
London. (Read November 22nd, 1803.)
[Plate I.]
In a paper on 4 The Shap Granite and the Associated Igneous and
Metamorphic Rocks ' 1 the authors, Messrs. Harker and Marr, did
me the honour to refer to certain statements made by mo in the
year 1884 2 with regard to the microscopic structures of a perlitic
felsite, associated with the Coniston Limestone where it crosses the
northern end of the Long Slcddale Valley in Westmoreland.
The opinion which 1 then expressed was that " spherules may
cause the devitrification of a rock after it has solidified and after
perlitic fission has supervened." A list of the structures, present in
tho section examined, was also given in the following order of
sequence: — 1. Fluxion-bands. 2. Perlitic structure traversing these
bands. 3. Minute spherules constituting tho whole rock, so far
as spherules can do so,3 and passing through the perlitic fissures.
4. Subsequent fractures. 5. Formation of quartz-veins along these
lines of fracture.
In the following year (1885) I again referred to this rock in
one of the Memoirs of the Geological Survey,* remarking that
" Sphcrulitic devitrification followed the development of the perlitic
structure.'*
Messrs. Harker and Marr, after alluding to the microscopic draw-
ings of this rock published in Mr. Tcall's ' British Petrography '
(1888) pi. xxxviii. and to my own remarks, namely those which
have just been cited, made the following observation : — "The latter
author has expressed the opinion that the sphcrulitic structure is
here an effect of devitrification subsequent to the perlitic cracking ;
but we are unable to sec that he has given any reasons for this
view. The practice of assigning a secondary origin to special struc-
tures in the older acid lavas has perhaps been pushed to excess in
some quarters. In the Westmoreland rhyolites there are traces of
perlitic fissures traversing rocks which are now microcrystallin*',
and other appearances pointing to the alteration of an originally
glassy mass ; but we find nothing to suggest that the sphcrulitic
and allied structures are of formation posterior to the consolidation
of tho lava : and tho breaking up of the vitreous material of tho
rocks examined seems to havo been in many cases a chemical, not
merely a molecular change."
Being averse to controversy, I might have allowed this statement
1 Quart. Journ. Geol. Soc. toI. xlvii. (1891) p. 303.
2 Ibid. vol. xl. p. 345.
8 The devitrification of this rock is in some places microcry»talline.
* ' Tho Felsitic Lavas of England and Wales,' p. 13.
Digitized by Google
Vol. 50.]
PEHLITIC AND SPHERULITIC STRTCTUKKS.
u
to pass unchallenged ; but, on casually looking through the pages of
the first part of the new edition of Prof. Zirkcl's * Lchrbuch der
Petrographie ' and finding therein an allusion to Messrs. Harkor
and Marr's criticism of my views, it seemed incumbent upon me to
defend my statements.
Owing to the length of their very admirable paper, it is possible
that the particular passage in question was not read at the meeting-
Had it been, I should probably have responded during the discussion.
The point at issue is, in a certain sense, a small one, since the
structures themselves are usually microscopic ; but its significance is
larger than might, at first sight, appear, since it involves the re-
tention or abolition of au old-established landmark in petrography.
In approaching this particular question we have to consider what
a rock once was, as well as what it now is. And, here, a difficulty
to which I have often alluded steps in.
We have to distinguish between those rocks in which a miero-
or cryptocrystalline structure has been set up prior to, or during
consolidation, as in lithoidal rhyolites ; and those in which such
structure has been developed after consolidation, as in devitritied
glassy rhyolites and obsidians.
Among the older rhyolitic rocks there is but one structure, the
perlitic, which, when present, affords what has hitherto been re-
garded as a certain proof that a rock assumed a vitreous character
at the time of consolidation. It is a valuable means of diagnosis,
which must hold good until it can be proved that perlitic structure
can be set up in a rock which already possesses a micro- or a crypto-
crystalline structure.
If we examine the more recent rhyolites, and compare those of
a vitreous with those of a lithoidal character, we find that the
former frequently exhibit a perlitic structure, while in the latter no
such structure is ever seen, assuming, of course, that the lithoidal
character is not the result of subsequent alteration.
I am unacquainted with a singlo instance in which this structure
has been developed in a recent lithoidal rhyolite, even when the
rock is mainly micro- or cryptocrystalline, still less would one expect
to find it in a rock cssentiall}* composed of small spherulitcs.
In a section of an obsidian from the Yellowstone, largely com-
posed of minute spherulites traversing the rock in bands, a perlitic
structure has been set up in the vitreous portions of the rock, but
that it has been developed subsequently to the formation of the
spherulites is sufficiently proved by the way in which the perlitic
cracks here and there encircle an isolated spherulite and by the
manner in which the larger cracks follow the boundaries of the
spherulitic bands (PI. I. fig. 3). In another rock from the Upper
Geyser Basin, Madison River, Yellowstone, which is almost wholly
composed of small spherulites, there is no evidenco whatever of
perlitic structure. In another similar rock from the Lower Geyser
Basin, perlitic structure is also absent. These are beautifully fresh
examples, and should show the structure well if it were present. In
Digitized by Google
12
MB. F. RUTLET ON THE 8EQUEXCE OF [Feb. 1894,
the first of those cases which I hare cited the pcrlitic structure is
present only in the vitreous portions of the section, and it has been
developed subsequently to the formation of the spherulites. In tho
line example of obsidian from Pilas, Jalisco, Mexico, described and
figured iu the Journal of this Society,1 tho development of the
perlitic structure has also followed that of the spherulites. Of this
there can bo no doubt.
Being anxious to adduce an instance in which the order of suc-
cession is reversed, i. e. where the spherulitic has succeeded tho
perlitic structuro, a section of pcrlitic obsidian from Buschbjd,
near Meissen, was selected. Here in the clearest manner a sphe-
rulite or a group of spherulites (PI. I. fig. 4) may be seen to havo
formed across a perlitic crack, just as in the devitrified obsidian of
Long Sleddale (PI. I. fig. 2); and that tho spherulites in the
Meissen rock arc devitrification-products there can bo no question,
siljeo they often follow the pcrlitic fissures, are irregularly distributed,
and do not form streams. A section of a devitrified obsidian from
Boulay Bay, Jersey (PI. I. fig. 5), containing coarse spherulites,
shows well-marked perlitic structure in the once vitreous portions,
which are now microcrystalliue in structure. The boundaries of
these microcrystalline grains sometimes abut against the perlitic
fissures and at others traverse them. The perlitic was in this
case developed before the microcrystalline structure.
Re-examination of sections of the Long Sleddale rock shows mo
no reason to alter the conclusions at which I formerly arrived, nor
do I doubt the value of pcrlitic structure as a means of recognizing
the originally vitreous character of the rock, or of that portion of
the rock in which it may happen to occur. Perlitic structure is
known to be developed in amorphous bodies, natural and artificial ;
and in no single instance, so far as I am awaro, has it been detected
in those which can be proved to have been in a crystalline or micro-
crystalline condition at the time of consolidation. That the Long
Sleddale felsite may vary considerably in structuro within a very
limited area is extremely probable, and it may be that the specimens
collected and examined by Messrs. Uarker and Marr differed in
some respects from mine. The original section upon which my
statements were based is at their disposal and will, I trust, help to
demonstrate that perlitic structure is not developed in the spheru-
litic parts of a vitreous or of a once vitreous rock, but that a spherulitic
structure may be superinduced in a rock in which perlitic structure
has already been developed. In this case the pcrlitic structure
appears to traverse the spherulites. In reality it is traversed by
them. On the other hand, when spherulites havo been developed in
jiarts of a vitreous rock and perlitic structure has been set up after-
wards, the latter will not transgress the boundaries of the spheru-
litic area 8 but will be restricted to tho glassy portions of the rock.
Finally, cases may occur in which both structures have been simul-
1 Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 630.
Digitized by Google
Vol. 50.] rERLITIC AND SPHERCLITIC STRUCTURES.
13
taneously developed, but I am unable to quote any example in
which there is proof of this.1 The man who can first develop
perlitic structure in a crystalline mass will do much to upset what
has hitherto been written concerning vitreous rocks. It is to bo
hoped that experiments in thia direction may be tried by those who
anticipate successful results.
It is possible that time may show that the views entertained by
Messrs. Harker and Marr are correct upon this point, but, in the
absence of further evidence, I adhere to my original statements.
EXPLANATION OF PLATE I.
Perlitic and SpheruJitic Structures in Vitreous and Devitrified Lams.
Order of
development
of structures,
let.
Perlitic.
2nd.
Spberulitic,
also in places
Macrocrystal-
line.
1st,
Sphcrulitic.
2nd,
Perlitic or
Synchronous.
1st.
Perlitic.
2nd,
Spherulitic.
1st.
Spberulitic.
2nd.
Perlitic.
3rd,
Macrocrystal-
line.
Ft*. 1. Long Sleddale, We«troorelnnd. Perlitic crack*, x 140.
Fig. 2. The same cracks as those shown in fig. 1, but with
the positions of three spherulites, as seen between
crossed uicols. It is noteworthy that, where these
spherulites have been formed across the perlitie
band res. the hitter are often barely perceptible, or
are completely obliterated. For the sake of clear-
ness the other spherulites and microcrystalline
graius, by which the rock is totally denitrified. ha\e
been omitted. Had the entire field been represented
as filled with spherulites, the point emphasized in
the text would not have been apparent
Fig. 3. Yellowstone, Montana, U.S.A. Spherulites surrounded
by perlitic cracks. These spherulites give a well-
defined dark cross in polarized light. X 140.
Fig. 4. Buschbad, near Meissen. Perlitic cracks traveling
spherulites (a). The latter are of later formation
than tho cracks. X 30.
Fig. 5. Boulay Bay, Jersey. On the right-hand, perlitic cracks
in devitrified obsidian (microcrystalline) : on the
left, part of a large spherulite (s) which is not tra-
versed by the perlitic structure. X 30.
Discussion.
Mr. Marr thanked the Author for the very courteous manner
in «which he had spoken of his opponents. lie was pleased to
have elicited this interesting communication from Mr. Kutley, but
regretted the absence of his colleague Mr. llarker, which neces-
sitated his muking an attempt to reply to the paper. With regard
to the Long Sleddale rock, he thought it was simpler to understand
perlitic cra< ks being arrested by spherulites than to suppose that
the spherulites formed across and obliterated pre-existing perlitic
cracks. The confident way in which tho Author had spoken of the
Meissen rock seemed to imply that he was, even now, not so confident
1 The cbsidian from tbo Yellowstone (PI. I. fig. 3) may possibly have had
both structures simultaneously developed.
Digitized by Google
14
PERLITIC iND SPRERrEITIC STRUCTURES.
[Feb. 1894,
with respect to that from Long Sleddale. Mr. Harker had informed
him (the speaker) that * giant spherules' occurred with perlitic
structure inside ; in this case it was difficult to imagine the formation
of the spherules subsequent to the consolidation of the rock.
Alluding to Mr. Watts's discovery of a structure resembling
perlitic structure in quartz, the speaker deprecated the custom,
somewhat rife among geologists, of giving too restricted defini-
tions. If a structure so like perlitic structure as to be practically
undistinguishable from it occurred in quartz, it might also occur in
other crystalline material.
Dr. J. W. Gregory was, like Mr. Marr, not satisfied that the
spherulites in the Long Sleddale rock were later than the perlitic
cracks, as such cracks often end off against solid inclusions in the
glassy lava. In the Yellowstone Park cases the spherulites are
often old ones in a re-fused lava, and the pcrlitcs have bent round
them. The figure of the Buschbad case is also not conclusive, as
some points in the figure suggested that the perlitic cracks might be
the earlier.
The Author, in reply, again pointed out what he regarded as the
order of sequence of the different structures in the rocks described,
and alluded to the sections exhibited by Mr. Watts, in which
a structure, seemingly perlitic, traversed crystals of quartz. He
doubted whether these cracks were really to be regarded a6 identical
with true perlitic structure. In reply to Mr. Marr, he stated that
he had never met with any case in which a perlitic fissure was
interrupted and abruptly cut off by a previously-formed spherulite,
but cited instances in which 6uch fissures accommodated themselves
to the surfaces of comparatively large spherulitic bodies. He also
briefly replied to Dr. Gregory's remarks.
Digitized by Google
PERLITIC & ST»KKmiLITiC 5>T HIJ CTURES .
Digitized by Google
Vol. 50.]
THE BASIC ERUPTIVE ROCKS OP GRAN.
15
3. Hu Basic Eruptive Rocks of Gran. (A Preliminary Notice.)
By W. C. Brooger, Ord. Professor in Mineralogy and Geology
in the University of Christiania, For. Memb. Geol. Soc. (Read
November 22nd, 1S93.J
Contests.
Page
I. Introduction 13
II. The Olivine-Gabbro- Diabases 18
III. The Effects of Contact-metaniorphism by the Olivine-Gabbro-
Diabase 21
IV. Tbe Cnrnptonitee and Bostonites 23
V. Their Origin by Differentiation 2tt
VI. Differentiation in the Bosses 31
VII. Conclusions :J5
Maps 16, 17
I. Introduction.
Ever since the beginuing of the present century, when the first
pioneers in the geological exploration of Norway (Keilhau, Haus-
mann, Leopold von Buch, and Xaumann) investigated the Christiania
region, the igneous rocks of that district have been famous as being
of more than common interest, as well from tbe many unique and
remarkable rock-varieties as from the exceptionally instructive
development of contact-metamorphisra produced by the eruptions,
and first brought to notice in this region through the observations
of Keilhau, Naumann, and Kjerulf.
In several preliminary communications1 on the igneous rocks of
tho Christiania region I have attempted to prove that all the
numerous different masses of eruptive rocks within the sunken
district between Lake Mjosen and the Langesundsfjord are gene-
tically connected, and have followed each other in a regular
buccession ; the oldest rocks are tho most basic, the youngest
(except the unimportant basic dykes of diabase) are tho most acid,
and between the two extremes I have found a continuous series.
Of late years I have proceeded in a moro detailed manner with
my investigations of the igneous rocks of tho sunken tract of
country in the Christiania region. I have not as yet in these
studies discovered any facts in contradiction to my previously
published observations and the deductions founded thereon. On
the contrary, more detailed and minute investigation has only con-
firmed the correctness of former publications.
1 ' Ueber die Bildungsgeschiehte des Kristianiafjords,' Nyt Mag. for Natur-
ridenskabemc, vol. xxx. (188<>) p. 99. Also, in a detailed address at the
meeting of the Association of Scandinavian Naturalists at Christiania, June
1886. A rtsumi was likewise published in my work, 'Die Mineralien der
Svenit-FegtnatitcHnge der sudnorwegischen Augit- und Xophelinsvenite '
Zeiuichr. f. Kryatallogr. u. Min. vol. xvi. (1890). r 3
Digitized by Google
10
THE BASIC ERUPTIVE ROCK 8 OP GRAN.
[Feb. 1894.
I completed in the summer of 1893 a collection of observations for
final publication ou the oldest basic series of igneous rocks of the
Christiania region, and I have now the honour of laying before
this learned Society a risume of the most important results of this
detailed investigation on the first eruptive series with which tho
long sequence of volcanic outbursts in the Christiania region com-
menced in Devonian times.
These oldest eruptions have left a series of interesting plutonic
rocks in a number of localities in the parish of Gran, between 50 and
60 kilometres (30 to 35 miles) N.X.W. of Christiania, and near
Dignces, on Lake Tyrifjord, about 35 kilometres (22 miles) W.N.W.
of Christiania.
MAP or- the
CIIKISTMIUMOY
Gramitite.
Onnrrt- Syenite.
\Jiatn AW**.
[ />TTVM»7»llf d*
ISUmrutH.
A rchuan.
Scat*. 1 1,250,000
- 05068 inch to the
milt, or about 19-73
miles to the inch.
The occurrences in Gran arc all situated on a great volcanic
fissure-line, in an almost north-and-south direction, parallel with the
general direction of the neighbouring Lake llandsfjord, the boundary
of the sunken tract in that part of the country. The great fault-lines
of Bandsfjord cut the Archaean mass of land at Na*s in a south-
south-west to east-north-east direction. Only a few kilometres east
of this fault-line we find the fissure of the basic eruptions indicated
by a series of mostly dome-shaped hills. In order, from north to
south, they run as follows : —
Brandberget (Brandbokampen), 514 metres (1070 feet) above
tho sea, an imposing hill.
Subsequently there appear several quite small exposures near
Augedal, Solberg, and south of Bilden.
Digitized by Google
SKETCH-MAP OF GRAN reference.
(CHRISTIANIA DISTRICT) EH3 Quartz Syenite (\ »rd,*arkitc).
BY IV. C.B/tOGGEK <5h TMi/XSTER. ^^DyktsofSolv*Urg*t(.Egyrin<4rachyic!
Scale. 1. 75V, 000 D7kes "/ Kkcmttm fiorfihyry.
— 4225 inch to the mile, or about 2-36 I l±2s/tsets c/Ca mfitoniU&BoitcmiU-brtccia
Note.— The numerous dvbes of camptonite and bostonite are entirely omitted
in the above map, because it would be impossible to represent them
satisfactorily on so small a scale.
Q.J.G.S. No. 197. c
Digitized by Google
18
rROP. W. C. BB.OGGER ON THE
[Fob. 1894,
A more considerable occurrence, Solvsberget, is there met with
(!) kilometres or 5j miles south of Brandberget), a fine eminence,
4S4 metres (1575 feet) in height.
Four kilometres (2£ miles) south of Solvsberget we find the two
hills of 4 Yiksfjeldene ' (the Vik mountains), Kjekshushougen and
Buhamraeren, 537 and 538 metres (1745 & 1749 feet) respectively
above the sea-level.
The occurrence at Dignses, on Lako Tyrifjord, is about 40 kilo-
metres (25 miles) south-west of Buhammeren.
The plutonic rocks in each and all of these localities are closely
connected by numerous passage-types, and present a wholly con-
tinuous series of basic abyssal rocks. It seems, therefore, impossible
to doubt that all these rocks, so closely allied in composition
and geological occurrence, have originated from a common source.
The limited time at my disposal allows only of a very summary
description of the principal varieties.
II. The Oli vixe-G a bbro-Pi abases.
The prevailing kinds of rock in all the greater occurrences (Brand-
bcrget, Solvsberget, Viksfjeldene, and Dignojs) we may characterize
as olivine-gabbro-diabases. They are medium- or coarse-grained
rocks of granitic structure, often also ophitic; there is not the
slightest trace of the ordinary changes met with in regionally meta-
morphosed gabbro. The mineral composition is, firstly, plagioclase,
the constitution of which varies, mainly from Ab,An, to AbaAn,,
and consequently it belongs to the labradorite series ; quite sub-
ordinate, a small proportion of orthoclase is also proved to occur in
several specimens (in the main rock of Solvsberget it is very
common). Besides the felspar a mineral of the pyroxene group
prevails: the common pyroxene in these rocks is a violet, tita-
niferous, lime-magnesia-pyroxenc, with comparatively small amounts
of aluminium- and iron-oxides ; olivine and a dark reddish-brown
biotite (lepidomelane) are both common constituents. An ortho-
rhombic pyroxene (bronzite or hypersthene) is observed in the
rock of Solvsberget, but in very small quantities. Basaltic brown
hornblende is rarely present, and then in small quantity. The
common iron ores, titanic iron and magnetite, in small amounts,
also pyrite, pyrrhotite, and apatite, the last often abundant, make
up the rest of the primary components.
A detailed petrographical description of the varieties of the
olivine-gabbro-diabase in the different localities, and, still more, a
thorough study of all the facies-types, would carry us too far. I
shall therefore, on this occasion, confine myself to pointing out the
important circumstance that the prevailing rocks in tlie different
exposures along (lie fissure clearly change their character in a
regular manner from north to south. On the whole, the average
basicity of the prevalent rocks can be proved to decrease in that
direction.
Digitized by Google
Vol. 50.]
BASIC ERUPTIVE BOCKS OF GRAN
In the northernmost locality, Brandbcrget, the prevailing rock is
a very basic olivine-gabbro-diabase, so poor in felspar that it passes
into pyroxenite. Jointly with this predominant rock there occur
also, to a great extent, typical pyroxenites, often of very coarse
grain, besides coarsely radiated hornblendite (with the hornblende-
prisms measuring as much as 10 centimetres or 4 inches in length),
the latter rather subordinate, and also subordinated hornblende-
bearing gabbro-proterobases and other rocks with brown basaltic
hornblende. These basic rocks (the pyroxenite, the hornblendite,
and the gabbro-proterobase) arc traversed by innumerable segrega-
tion-veins of a fine-grained augite-diorite or augite-syenito (akerite),
which will be further referred to a little later on.
Moreover, in the small exposures of Augedal, Solberg, and Bildcn,
very basic varieties — pyroxenites combined with camptonites —
prevail.
On the top of Solvsbcrgct a more acid olivine-gabbro-diabase is
already the prevalent rock ; pyroxenites and other basic rocks aro
there only observed as rather subordinate contact-facies.
We find the same conditions in the Viksfjeldene, where also moro
acid segregation- veins of augite-diorite, etc., are widely spread.
The most acid rock is represented in the occurrence at Dignies ;
the ultrabasic types are entirely wanting here, the predominant
rock being an olivine-gabbro-diabase rich in felspar.
The following analyses (Table I.) serve to illustrate the successivo
changes in the chemical composition of the prevalent kinds of rock
from north to south : —
Table I.
I. TI. III.
SiOa 4365 47-00 4025
TiOa 4-00 2 30 1-41
ALO, 11 48 15-20 16 97
Fe,0, 6 32 5(191
Feb:. 8 00 6-59/ L,2i
MnO Trace 026 Trace
MgO 7 92 8-76 abt. 3 00
CaO 14 00 12-60 7 17
Nap 2-28 145 4 91
KO I'M 0 66 2 01
H:0 HM) 0 30 abt. 0 30
pp, Trace Trace 076
CuCO, Trace Trace
100 16 10081 abt. 10099
I. OliYine-gabbro-diabase of Brandberget ; analysis by L. Schroelck.
II. Do. of SoWsberget; analysis by Sarnstrom, the alkalies determined by
L. Schmelck.
III. Do. of Digna?*; analysis by A. Damiu, the alkalies determined by
L. Schmelck.
c2
Digitized by Google
20 PROF. W. C. BROOORB ON THE [Feb. 1 894,
According to an approximate calculation from the above analyses,
the mineral composition per cent, may be estimated as follows : —
Table II.
I. II. III.
Brandberget. Svhsberget. Digixrs.
Felspar* about 12 about 4fi about fV4
Pyroxene 09 20 10
Olivine 5 12} 9
Biotite 3 !>j 8i
Iron Ore* 7 5 Ci
Apatite, serpentine, 1 4 1 o
chlorite, etc. ... J
loo 100 100"
The average composition of the three principal varieties of olivine-
gabbro-diabase, the iron being calculated as FeaO, (all analyses
calculated free from water, and finally equalized by reducing thorn
to 100 per cent.), is as follows : —
SiO, 4<V48
TiOa 250
Al,Oa 14 50
FeO, 1444
MpO <S :A
CaO 11-23
Na..O 287
K,0 1-38
100-00
The olivine-gabbro-diabase of Solvsberget, as will be thus seen ,
differs only slightly in composition from the average rock.
The rocks in the northern occurrences of these oldest eruptions in
the Christiania region are then, as wo have seen, mainly pyroxenic
rocks of a basic character, while the southern localities along
the same fissure show chiefly felspathic rocks of somewhat greater
acidity. Probably the average composition of all the masses of rock
in Brandberget diners only slightly from the abovo-calculatod average ;
on the other hand, it is certain that the average composition of the
rocks from Dignocs is more acid than this average. We have, there-
fore, here a remarkable example of the differentiation of a molten
magma in a regular manner in horizontal direction along connected
fissure-lines. Nor is it the only case of its kind in the Christiania
region.
With respect to the geological appearance of these abyssal rocks,
I will simply remark that they are only partially of a laccolitic
character ; as a rule they are enveloped as vertical bosses, the
contact-plane often cutting the adjacent Silurian strata.
The small exposuro south of Bildcn is, on the whole, an inclined
laccolitic sheet, the rocks in the same chiefly showing a porphyritic
structure and the composition of the camptonite-group, and being
only to a slight extent crystallized as pyroxenites. On tho
Viksfjeldene also the laccolitic character is evident.
Digitized by Google
Vol. 50.]
BASIC ERUPTIVE ROCKS OF GKAN.
21
As an example of partly laccolitic bosses we will take the case of
Solvsberget.
Solvsberget is a roof-shaped hill, about 1*5 kilometro (1 mile) in
length from north to south, and about 1 kilometre (j mile) in width
from west to east; the top is elevated about 250 metres (813 feet)
above the surrounding country ; the eastern side is very abrupt, the
western side more gradually sloping. In its northern and southern
part 8 Solvsberget is formed of Silurian (Ordovician) strata of dta^cs
4 a a and 4 a /3 (shales with Oyygia dilatata, Briinn, and Ampyx-
limestone) ; the main strike is west to east, or west-north-west to
east-south-east, the dip generally showing angles varying from 50c to
80°. The central part of the hill is occupied by the eruptive rockB ;
on the map it will be seen that their surface, in horizontal projection,
baa a boomerang- like shape ; in the south-western part the strata
are vertically traversed by the plutonic rock ; in the middle of the
* boomerang' the eruptive rock appears to bo conformably injected
between the shales ; but in the eastern part the eruptive surface
suddenly sinks to a lower level, and seems there partly to be of a
laccolitic character. The whole surface occupied by the plutonic
rocks is only 03 square kilometre (75 acres;.
III. Thb Effects op Contact-metamorphism bi the Olivine-
Gabbbo-Diabase.
Id all occurrences of these plutonic rocks we find a typical abyssal
contact-metamorphism, the peripheric extent of which depends on
the size of the plutonic masses in the different localities. At
Solvsberget the alteration of the Silurian strata is perceptible at
distances of 200 or even 300 metres (220 or 330 yards) from the
boundary on the eastern side of the hill, where the strikes of the
stratified rocks and of the eruptive boss run in nearly the samo
direction ; in the south-east the observed alterations terminate much
nearer to the eruptive rock.
The unaltered rocks of Solvsberget are tbo com uion, black to dark
grey, argillaceous shales of etage 4aa (Ctyyj/ia-sbales), with a few
iuterbedded lenticular masses of limestone. By the contact-meta-
morphism the shales, as usual, are altered into dark violet hornstones,
shimmering, as we get closer to the boundary, more and more from
innumerable small scales of mica, the diameter of which close to the
boundary attains several millimetres. In the next zone of alteration
the hornstone is macroscopically crystalline, with a grain of medium
size, often possessing a very remarkable porphyritic structure, due
to crystals of plagioclase more than 5 millimetres inch) long. The
limestone-lenses are altered into calcareous hornstone (kalksilikat-
hornfels).
The contact-metamorphism along the boundary of the olivine-
gabbro-diabases of Gran is mainly of interest, because the micro-
scopical observations on the altered rocks make it very probable
that the previous supposition, as to the independence of the
alteration in regard to the composition of the plutonic rock itself,
Digitized by Google
22
PROF. W. C. BROGGER ON THE
[Feb. 1894,
can be proved to bo incorrect. I had myself believed till now
that contact-metainorphism in strata of the same nature, by other-
wise identical conditions, has generally given rise to the same
alteration-products — without regard to the ' chemical quality 'of the
eruptive rock in question. The development of the contact-mcta-
morphism in Gran seems now to prove that this opinion was
erroneous.
The short time at my disposal does not allow of a detailed
description of all the observations upon which I found my altered
opinion. I shall only mention a single fact.
Along the boundary of the basic plutonic rocks of Gran, all of
which are comparatively rich in magnesia and iron oxides, the more
highly altered hornstoncs of the Cty//</i«-6hales show an essential
percentage of hypersthene. I had previously mistaken the mineral
for andalusite ; it occurs as innumerable small prismatic crystals,
but is easily distinguished by its optical characters. To make
assurance doubly sure, I have, with considerable difficulty, isolated
a small portion of the hypersthene, and have had it analysed by
Herr L. Schmelck. The analysis gave : —
SiO, 4810
FoO 2228
MilO 21 M
CaO 220
94-41
Tho loss is due to a mishap in the course of determination of the
silicic acid ; adding 5-56 per cent. Si02, the above analysis agrees
exactly with the composition of an hypersthene, in which the
molecular proportions aro
FeO : (MgO, CaO) = 1:2.
Now the very same strata of the Ogygiashalea, 7 kilometres
(4\ miles) cast of 8olvsbergct, are altered into horn stones by the
influence of the immense masses of quartz-syenite (nordmarkite) ex-
tending over the whole district between Gran and Christiania. I have
examined a number of specimens of these hornstones from Il&n8sen
and other localities. In none of them have I discovered the slightest
vestige of hypersthene. As is well known, hypersthene or ortho-
rhombic pyroxene is, upon the whole, never observed to have been
produced by contact-metamorphism alongside abyssal rocks.
It seems, therefore, that in this case the basic magma of the
olivine-gabbro-diabase, as compared with the acid magma of the
quartz-syenite, must have influenced, in a peculiar manner, the
argillaceous shales of etage 4 a a by altering them into hyperstheue-
bearing hornstones. Whether this special influence is due to a
transfer of magnesia and ferrous oxide from the magma, or not, is a
problem which can only be settled by a series of analyses as yet
unfinished.
In other respects, too, the contact-metamorphism alongside the
above-dedcribed basic rocks is of interest ; but, as this question is
Digitized by Google
Tol. 50.]
BASIC ERUPTIVE ROCKS OF GRAN.
23
apart from my main subject, I must defer observations in connexion
therewith to another occasion.
The small and insignificant basic abyssal masses of Gran are not
in themselves of sufficient importance to justify me in occupying the
time of this Society by describing them. There are, however, other
circumstances, not as yet referred to, which give them gTeat interest.
They are accompanied by a great series of dykes and sheets, the
study of which throws much light on those processes of differentia-
tion which are just at present being made the object of thorough
research by petrologists and geologists.
IV. The Camptosites axd Bostonites.
Along both sides of the entire fissure-line on which the abyssal
rocks are situated, we find an innumerable multitude of dykes and
sheets of camptonite and bostonite, two kinds of rock which have
formerly been admitted to be closely associated with masses of
nepheline-sycnite.
Camptonite (lamprophyric dyke-rock essentially composed of basic
plagioclase and brown basaltic hornblende, often porphyritic from
pheuocrysts of the latter mineral) has been previously described
from Campton Falls in New Hampshire 1 ; Montreal in Canada2;
Forest of Dean in Orauge Co., N. Y.3 ; Fort Montgomery (Fairhavcn,
Proctor, etc.) in the Hudson River Highlands 4 ; Whitehall in Wash-
ington Co., N. Y.5 ; Lake Champlain Valley 8 ; nearly allied rocks,
though hardly typical camptonites, are described from Val Avisio in
the Tyrol7; Inchnadampf in the Scottish Highlands'1; Waldmichel-
bach and other localities in the Spcssart.*
The name • bostonite' was introduced by Rosenbusch and applied to
dyke-rocks with trachytic structure, essentially composed of felspars
without dark minerals ; a more detailed description is given by
Kemp. Bostonites are known from Marblehead near Boston, 10
Montreal in Canada,10 Serra de Tingua in Brazil,'1 and from Lake
Champlain ValJey.1J In all previously described occurrences the
bostonites are connected with different basic dyke-rocks, and with
masses of nepbeline-syenite (?) in the vicinity ; among the asso-
ciated basic rocks near Montreal and Lake Champlain there are
also camptonites.
1 G. W. Hawes, Am. Joum. Sci. Mr. 3, vol. xvii. (1870) p. 147.
2 B. J. Harrington, Geol. Sun-, of Canada, Report for 1*77-78 G, p. 42.
5 J. F. Kemp. Am. Journ. Sci. scr. 3, vol. xxxv. p. 331.
4 Id. " Atner. Naturalist' for 1888, p. 601.
* Id. and V. F. Marsters, ' Amer. Geologist,' vol. ir. (1889) p. 07.
* J. F. Kemp and V. F. Marsters, Trans. N. Y. Acad. Sci. vol. xi. (1801)
p. 13.
7 Com. Dolter. Tschermak's Min. Mitth. (1875) pp. 179, 180, 304 ; A. Cath-
rein, Zeitschr. f. Krvstallogr. u. Min. toI. Tiii. (1884) p. 221.
* J. J. H. Teall. Geol. Mag. for 1880, p. 340.
9 Erw. Goller, Inaue. Diss. (Strasbourg, 1889).
10 On literature, see Kemp and Marsteru, op. mpra cit. p. 17.
11 M. Hunter and H. Eoaeubusch, Ts.-hermak's Miu. u. Petr. Mitth. toI. xi.
(1890) p. 445.
lt Kemp and Marsters, op. supra cit.
Digitized by Google
24
PROF. W. C. BBoGGER OK THE
[Feb. 1894,
In the parishes of Gran, Hole, Modum, etc., in the Christiania
region, these rock- varieties are exceedingly abundant; they appear
partly as vertical dykes, generally with a north-and-south or north-
north-east and south-south-west strike, parallel to the main strike of
the fissures, on which the bosses of olivine-gabbro-diabase and
other basic abyssal rocks are situated, along the lines Brandberget-
Sblvsberget and Buhammeren-Dignaes. In one part they are also
arranged as intrusive sheets introduced between the Silurian strata,
chiefly closo to the surface of the Archaean schists, especially in
etages 1 and 2, also in 3 and 4, and less often in tho higher etages.
Although the surface in Gran is somewhat obscured, several
hundred occurrences, of dykes as well as sheets of camptonite and
bostonite, have been observed. As an examplo of the frequency of
the dykes, I may mention that in one area alone (along the
Melbostad and Helgum road) I counted more than 50 dykes in
1£ kilometre (1 mile); the total thickness of these dykes I measured
to be 70 metres (227 feet), that is 1 metre of dyke-mass in every 20.
The thickness of the dykes is commonly £ to 2 metres (1^ to 6 \ feet) ;
it seldom attains 5 or 10 metres (16 or 32 feet).
The thickness of the sheets is usually also 1 to 2 metres, less
often 10 metres or more; however, a great number of intrusive
sheets often follow upon each other, which is the reason why the
total thickness in several localities may amount to 20 and even 30
metres (65£ to about 100 feet).
In the vicinity of Brandberget the magma has in preference been
intruded as sheets between the planes of the stratified rocks ; in tho
neighbourhood of Solvsberget, on the contrary*, vertical dykes are
more prevalent ; perhaps this circumstance can be explained by the
fact that at Sblvsberget we find only higher etages (such as e'tage 4)
represented.
The camptonitcs and the bostonites are very intimately con-
nected with each other, and also with the above-mentioned boss-
rocks. These connexions are proved by the following facts : —
Firstly, as regards the relation between the bostonites and the
camptonitcs, we may observe that they everywhere appear together
in close companionship. Thus, we find innumerable examples of
vertical camptonite-dykes associated with immediately adjacent
parallel dykes of bostonite; often tho same dyke-fissure contains
both bostonite and camptonite, and with equal frequency it happens
that both rocks appear together as intrusive sheets.
In many bostonite-sheets and dykes wo find phenocrysts of brown
hornblende, which is the chief mineral among the phenocrysts of the
camptonitcs. I have moreover observed several examples of dykes
or sheets in which the centre is bostonite, the sides camptonite, or
vice vexed. Finally, I have also, but less frequently, observed inter-
mediate kinds between camptonite and bostonite.
Secondly, as to tho relation between the eugranitic boss-rocks, on
the one hand, and the dyke- and sheet-rocks on the other, we may
remark that in Gran and the surrounding parishes the bostonites
and camptcnites are represented in many hundred dykes and sheets
Digitized by Google
Vol. 50.]
. BASIC ERUPTIVE ROCKS OP GRAN.
25
in the neighbourhood of the above-mentioned basic boss-rocks,
whereas other kinds of dykes appear very seldom. I have observed
only a small number of rhombcn-porphyries (plagioclasc-rhomben-
porphyry and common rhomben-porphyry, 7 or 8 great dykes partly
followed along a stretch of more than 20 kilometres = 12^ miles),
mica-syenite-porphyry and aegyrine-syenite-porphyry (Solvsbergct),
8 to 10 greater dykes ; finally, a number of diabase-dykes, etc. On
the other hand, the dykes and sheets of bostonite and camptonito
outside this tract, in which the basic boss-rocks occur, are very
sparsely distributed in the Christiania region, and not in the same
typical varieties as in Gran parish.
On Brandberget a hornblende-bearing rock, closely allied to camp-
tonite, locally appears as an unquestionable contact-facies of tho
olivine-gabbro-diabose.
In the small laccolitic sheet south of Bilden camptonite is tho
main rock ; pyroxenito appears here only subordinate and mostly in
the central parts ; and all the pnssage-types between camptonite
and pyroxenite are found. At Solvsberget also I have collected a
rock of the camptonite-bostonite series, an intermediate type bo-
tween both extremes, occurring locally as a contact-facies.
The above observations conclusively prove that tho caraptonites
and the bostonites are nearly connected with, and must be derived
from, the same magma as the previously-described boss-rocks.
Tho mutual relation of age between the camptonites and tho
bostonites is invariably as follows : —
WTien dykes of bostonite and camptonite cut each other, the
former, without exception, is tho younger.
In a bostonite (from Lindberget, on Lako Msena) I have found
rounded enclosures of basic masses partly of camptonite, partly of
pyroxenite ; these enclosures can only be explained as early crystal-
lizations of basic composition in a magma, from which the distinct
magma of the bostonite was not yet separated as a final product of
the differentiation.
In seven different localities (chiefly in Najs, south-west of
Brandberget) there appear considerable sheets of bostonite-breccia ;
the main localities of these breccias in Nods arc situated on the
continuation of the great fault-fissures of Lako Itandstjord, and
farther north-north-east continued in tho fault-crevice along the
bed of the Huns river. Tho breccias are brimful of angular
fragmcuts of Archaean schists and Silurian slates (chiefly alum-
shales) and limestones of the lowest etages (1-3), all the fragments
being cemented by a bostonite groundmass. In several blocks of
this breccia I have observed that every fragment is surrounded by
a more basic dark-green mass, partly of camptonitic composition ;
this basic matter, enveloping the angular fragments, is then itself
embedded in the scarce bostonitic groundmass. In a similar breccia
from Augedal I found a rounded lenticular mass of camptonitic rock
£ metre (13 inches) in diameter; this mass showed, on chemical
analysis, an undoubted camptonitic composition.
Digitized by Google
26 PROP. W. C. BROGGEB ON TOE [Feb. 1 894,
V. Their Origin by Differentiation.
The above-mentioned relations prove, in my opinion, that the
common magma, from which the basic bosses along the lines Braud-
berget-Sulvsberget-Viksfjeldene-Dignaes are crystallized as olivine-
gabbro-diabascs and pyroxenites,ete., must have been the same magma
as that from which the innumerable dykes and sheets of camptonite
and bostonite are derived ; and further, that all these dykes and
sheets have arisen as the result of a differentiation in the original
magma, in such a manner that first a basic portion, corresponding
with the camptonitic magma, has been separated out by diffusion,
aud, subsequently, tho remaining more acid magma has furnished
the material for the bostonite-dykes and sheets.
If theso views be correct, the chemical analyses of the different
kinds of rock should give undoubted proofs of the process of
differentiation in the original magma; and, in my opinion, they
do so.
The calculated average composition derived from the three
analyses of the olivine-gabbro-diabases of Brandberget, Solvsberget,
and Dignaes probably indicates very closely the average composition
of tho original basic magma, which was pressed up during the
oldest magma-eruptions in the Christiania region, along the western
boundary of the sunken tract. By differentiation in a magma of
this composition the separato magmas of tho caraptonito-, and the
subsequent bostonite-eruptions, must have been formed.
I have now caused a series of chemical analyses to be made of
camptonites and bostonites from one and the same locality, from
both sides of Brandberget : of camptonite from Lindbcrget on Lake
Mama, at tho western base of Brandberget, and from Egge on the
south-eastern side; also of bostonite from the same 1 cutting' as the
analysed camptonite. These analyses (by L. Schmclck) have yielded
the following result : — •
Table III.
IV. V. VI.
Cavipionitc, Metna. Camptonite, F<jgt. Bottoniti, Mfpua.
SiOa 40-00 4205 5050
TiO. 420 5 00 085
AL03 1255 12.il) 1814
Fe20, 547 3 81 312
FeO: 9-52 9 52 2 8*
MgO 8 90 4*3 122
OiO 10 80 11 \-»5 3 38
>n20 254 218 fr2*
K..0 119 111 100
CO 208 2<W 5 11
lip 2 28 2-88 1 20
100 79 98 51 90 32
All these rocks are from sheets ; they are, on the whole, rich in
carbonates. Calculating the substances free from water and car-
bonic acid at 100 per cent, (the iron as Fe/)3), we get: —
Digitized by Google
Vol. 50.]
BASIC ERUPTIVE ROCKS OF GRAN.
27
Tahle IV.
IV a. V a.
Ca m pto 11 ite, Ca m ptou ite,
SiO^ 41 90 44 73
TiOa 4 31 5 95
AU>3 12t»4 13 OS
Fe/), 10 57 15 32
MgO 9 25 .VI 4
CaO 11 14 1229
Ka..O 2 02 232
K20 1 24 1 17
100-00 100 00
A vera ye
of
IVa £ Vu.
43 31
5 14
1301
1594
11-71
2!0
1-20
Average of right
Camptonite
Analysis.
43-05
AM
10 29
14 7<>
5-90
10 10
3 05
1 50
100-00
100 00
In Table IT., parallel with the average of the camptonite
analyses from Ma?na and Egge, is placed the calculated average of
eight different camptonite analyses (from Campion Falls, Montreal,
lairhaven, Proctor, Fort Montgomery, Mana, Egge, Hougen) : and,
as will be seen, the differences are not great.
The following table (V.) shows the bostonite analysis from
^Ia?na, calculated in the same manner : for comparison I have
calculated the average of two American bostonite amilvses (from
Shelburne Point and Champlain Valley) published by J. F. Kemp
(/or. gujtra cit.). It will be noticed that the American bostonites
are richer in potash than the Norwegian.
Tahle V.
8i02
Ti02
Al./>,
Fe.Oj
MgO..
C*0 ..
Ka-O
VI a. Bort<mi(c,
M(tua.
60v>7
001
1945
<V70
1-31
302
6-tifi
1-72
Average of two American
Bostonite Analyses.
0073
21 "««)
383
0-79
444
4-52
409
100O0
10000
A simple calculation founded on the above data shows that a
mixture of 9 parts of the calculated average of the camptonites
from Maena and Egge, and 2 parts of the bostonite from Mama,
-would make a composition differing very little from the above
calculated (p. 20) average composition of the olivine-gabbro-diabascs
from Brandberget, Solvsberget, and Dignros.
Digitized by Google
28
rilOP. W. C. BROGQER ON THE
[Feb. 1894,
Table VI.
Average of Analyses of
Olirine- Difference.
Gabbro-
Diabiue.
46-48 -0-03
2;>6 +1 -81
1450 -U-32
14-44 -017
6 54 -0-39
11-23 -OIW
287 +017
1-38 -008
100-00 100-00
I am well aware that every calculation of this kind must agree very
accurately with actual fact if any importance is to be attached to it ;
the calculations of rock-compositions as the results of mixtures of a
basaltic and a trachytic magma, according to tho law enunciated
by Bunsen some forty years ago, are in this connexion warning
examples. In our case the accordance is very close in all tho com-
ponents, oxcept the titanic oxido and the lime. With respect to
the former, I may remark that its percentage varies between wide
limits as well in the camptonites as in the olivine- gabbro-diabases.
In the camptonites from Mama and Eggo the percentage of titanic
oxide is greater than usual, but iu the average of the olivino-gabbro-
diabases the small proportion of titanic oxide in the rock from Digntes
(see p. 19) lowers the average percentage somewhat considerably.
As to the lime, it must be observed that in the olivine-gabbro-diabases
the indicated percentage represents the whole of the lime originally
saturated with silica; while, in the average of the camptonites and the
bostonites, the lime percentage is calculated in rocks from which, by
abundant carbonatizing, a portion of tho lime originally present
has probably been carried away.
These circumstances being takon into account, I am of opinion
that the accordance is sufficient ; such an agreement cannot be
accidental. I think, therefore, I have sufficiently proved that the
camptonites and bostonites in Gran have been produced by differen-
tiation of an original common magma, whose chemical composition
agreed with the average composition of the olivine-gabbro-diabases on
the volcanic fissure-lines between Brandberget and Digna?s.
This differentiation can further be proved to have taken place in
a liquid magma, even before crystallization of any importance had
begun. This appears evident from the striking difference in the
mineral composition of the olivine-gabbro-diabases on the one
hand, and the camptonites and bostonites on tho other. In the
former, among tho minerals — that is, among the first crystallized
constituents — pyroxene, olivine, and dark biotito are prevalent,
brown hornblende wanting as a rule, or quite subordinate. In tho
camptonites, on tho contrary, tho predominant dark mineral is
always brown basaltic hornblende, often amounting to more than
Campfonitc
Bostonite.
SiOa 46-45
TiOa 4-37
ALU, 1418
FeaO, 14-27
MgO 615
CaO 10-24
No./) 3-04
K„G 1-30
Digitized by Google
Vol. 50.]
BASIC ERUPnVE ROCKS OF GRAN.
29
60 per cent, of the rock, while olivine and brown mica are often
wanting, and pyroxene is invariably subordinate.
We have consequently in the basic rocks of Gran a remarkable
example of the fact that one and the same magma partly without
essential differentiation has been pressed up to a higher level, and
there has crystallized out as large boss-masses (in the form of
olivine-gabbro-diabase), partly has been differentiated at a deeper-
seated level into a basic magma (which by its outburst has formed
sheets and dykes with porphyritic structure : camptonites), and into a
more acid residuary magma (which in the final eruptions has given
rise to sheets and dykos of bostonite). This differentiation (into
camptonites and bostonites) has partly also taken place in the dyke
and sheet-fissures themselves after passing up into a higher level.
In order to explain this fact, that one and the same magma has
in part been differentiated, in part not, it seems, in my opinion,
necessary to assume that in the latter case the essential cooling of the
magma has first taken place in the bosses themselves ; while, in the
former case, even before the final pressing-up of the magma, an
essential decrease of temperature and pressure along the contact-jilane
of the magma must have taken place in the magma-reservoir. In
this cooling and diminishing of the pressure tho magma must have
been subject to conditions necessary for producing a tendency to
crystallization of the brown basaltic hornblende, although in all
probability actual crystallization did not take place. Along the
contact-plane there must then have been concentrated by diffusion
a liquid stratum essentially containing the components of the brown
hornblende. This may be deduced from the fact that the composition
of the camptonite derived from this differentiated magma differs but
slightly from tho probable composition of the brown hornblende. 1
and from the other fact that brown hornblende is actually the
essential mineral of the camptonites. Theso facts then favour the
1 Tho analysis of the brown hornblende in the camptonites of Gran is not yet
completed. The difference between that and the composition of the camptonite*
hornblende published by Hawes is probiibly unimportant. I refer, therefore,
provisionally to his analysis for comparison with the average camptouite-
compoeition : —
Table VII.
Aitrage of ten
Analyse* of
Basaltic Hornblende.
SiO, 3988
TiO, 486
AlaO, 14-83
Fe„0 1260
Mj^O 12 27
CaO 1268
£&>:::} 339
Camptonite- Hornblende
(after Hawes).
40 79
(not determined)
1730
20-85
6-97
10-83
417 (diff.)
Atreraqe of eight
Anali/jtes o f
Camptonite.
43(55
403
16-20
14-76
506
10-10
4-55
100-51
100-97
100-00
The average of 10 analyses of basaltic hornblende is calculated from those
published by Schneider, Zeitachr. f. Krystallogr. u. Min. toL iriii. (1891) p. 579.
Digitized by Google
30
PROF. W. C. BRuGGER OJT THE
[Feb. 1894,
belief that the differentiation of the original magma has, to an
essential degree, been dependent on the laws which govern the
sequence of crystallization, an opinion already maintained by the
author several years ago (1S5>0), and further sustained, chiefly here
in England, by Teall.
The most easily cryst alii z able compounds (the least soluble) of
the magma have in the diffusion first accumulated along the
cooling margin. In the liquid magma itself the different coin-
pounds were probably dissociated, but the degreo of dissociation
most probably decreased with diminution of temperature and pres-
sure. Along the cooling margin of the magma a concentration
of dissociated compounds to less dissociated groups has thus taken
place, a concentration probably governed by the laws of chemical
affinity (see the views of J. H. L. Vogt). These compounds
(not identical with the 'kern*' of H. Itosenbusch) concentrated
by tho diffusion of the less soluble and more easily crystallizable
substances, under the stated conditions along tho contact- margin
of the magma, have then still been liquid or at least been liquid in
the main. In the camptonites and the bostonitos tho consolidation
evidently first began after the outburst of tho magma into the
fissures, which it has filled up.
The opinion that the most easily crystallizable compounds have
diffused to tho cooler portion of the magma and thero have
generated a magma-stratum of peculiar composition has been
doubted on the grounds that the rock crystallized after the eruption
does not show a stoichiometric composition 1 ; however, it seems
quite probable that this objection is not decisive. That, in the case
in question, the camptonite-magma differentiated from the olivine-
gabbro-diabase-magma has not exactly the same composition as
brown hornblende, finds a natural explanation in the fact that the
spaces of crystallization for minerals which can crystallize out of a
magma of given composition are well known to partly cover and
transgress each other. A diffusion of the compounds of the brown
hornblende, to the cooler margin of a magma of tho composition
above supposed, could not therefore have formed a magma of a pure
hornblendic mixture, but only such a composition mixed with an
addition of other compounds in subordinate quantities. This
admixture is, however, in our case not of any great importance.
Then we also find — agreeing with the fact that the felspar in the
camptonites crystallized as a rule after the hornblende — that tho re-
siduary bostonite-magma after the differentiation of the camptonite-
magma (setting aside the unimportant percentage of magnesia, iron
oxides, and titanic oxide) shows an almost felspathic composition
of medium acidity.
I think I have proved that the camptonites and bostonites in
Gran have been differentiated from a magma of tho average com-
position of the olivine-gabbro-diabases which appear in the same
tract. If the above-explained hypothesis bo admitted, this fact
seems not to be at variance with the observations from other countries,
1 hidings, ' On the Origiu of Igneous Bocks,' Bull. Phil. Soc. Washington,
toL xii. (18<J2) pp. 89-^14.
Digitized by Google
Vol. 50.] BASIC ERUPTIVE ROCKS OF GRAN. 31
that the above-mentioned kinds of rock aro otherwise connected
with nepheline-syenites. With the * hern ' hypothesis of Rosenbusch,
on the other hand, the above proved connexion does not seem to agreo.
\ Note. — For rock-types, differentiated out of a common magma, I
propose the name 'complementary rocks'; camptonit.es and bostonites
are, then, such complementary rocks. Between the dyke-rocks we
have also a number of other examples.
Complementary rocks should, therefore, in the classification of
rocks be placed in that rock-group which has a chemical composition
agreeing with the composition of the original common magma of the
complementary rocks ; minettes and aplites, for instance, are com-
plementary rocks of the granite-family, and so on.— Dec. liUth, 181KJ.]
VI. Differentiation is the Bosses.
The differentiation of tho olivine-gabbro-diabase magma into
camptonites and bostonites is not the only one which has taken
place in this magma. In the boss of Brandberget we find that the
same or a very closely allied magma has, by differentiation under
other conditions, given rise here to other products. It is true
that a magma of hornblendic composition (partly crystallized as pure
hornblendite, partly as a caraptonitic rock) was differentiated out
from the original magma ; but these masses are here quite unim-
portant. The conditions here have evideutly not permitted to any
great extent the crystallization of dark aluminiferous minerals, such
as brown hornblende ; consequently the differentiation of the magma
has not allowed the concentration of liquid compounds of analogous
composition along the margins of the boss. On the other hand, it
seems clear that tho ruling conditions have highly favoured the
crystallization of dark pyroxene^ rich in calcium, magnesium, and
iron, and relatively poor in aluminium. Agreeably to this supposition
we find that, along the margins of tho boss, especially in the west
and north, there has been differentiated a basic magma of an
almost pure pyroxenic composition, which has often crystallized as
very coarse-grained pyroxenitt, with as much as 95 per cent.
pyroxene. An analysis from tho laboratory of Herr L. Schmelck
gave the following composition for such a very coarse-grained
pyroxenite from Brandberget : —
Table VIII.
Pyroxenife, Pyroxene,
llrandbfratt. Limhmt.
SiOa 4505 44 -115
TiO. 205 293
A130, 650 61tti
Fe,0, 3 83 502
FeO 769 3 87
MgO 1 2 07 14-76
CaO 18-60 20 32
Na.0 0 94 120
K..0 0 78 0 49
Ca,PsO„ 031
H20 2-40
10088 wi>
Digitized by Google
32 PROP. W. C. BROGGEB OS THE [Feb. 1894,
For purposes of comparison the analysis by Merian (Xeues Jahrb.
1885, Beilagc, vol. iii. p. 285) of the pyroxene from Limburg, Kaiser*
stuhl, Baden, is placed beside that of the Brandberget rock. The
agreement between the rock and the mineral is, as will be seen, very
close.
The typical pyroxenite of Brandberget consists, practically in its
entirety, of dark pyroxene ; mingled with this, but quite subordi-
nate, are a little brown hornblende, reddish-brown biotite, traces of
plagioclase, etc. ; the structure is often miarolitic, with various
minerals (splendid crystals of titanite, apatite, etc.) in the open
cavities.
This pyroxenite is traversed by innumerable, comparatively acid
veins of fine-grained, light-grey augite-diorite, or mica-augite-
diorite, invariably rich in yellow titanite, and of a kind passing into
the series of augite-syenite, designated formerly by the author as
' akerites.' These veins of augite-diorite are so abundant that
tho rock on the whole of the western side of Brandberget represents a
typical eruptive breccia, containing angular fragments of the dark
coarse-grained pyroxenite cemented by the fine-grained, light-grey
augite-diorite. This latter then represents the acid residuary
magma after the differentiation of the pyroxenite-magma, already
consolidated to pyroxenite, when its veins were squeezed up.
The main mass of tho magma of Brandberget is not much
differentiated, but has crystallized out like the basic olivino-gabbro-
diabase mentioned above, differing only slightly from the above
calculated average magma of olivinc-gabbro-diabase.
All the products of crystallization on Brandberget represent,
then, the results of a special differentiation, which has taken place
in this boss itself. As we found above (p. 27) that 9 parts of the
camptonite composition, and 2 parts of the bostonite composition,
gave us the average composition of the olivine-gabbro-diabases of
Gran and Modum, in a similar manner it should be possible by the
mixture of some parts of pyroxenite, hornblendite, augite-diorite,
and olivine-gabbro-diabase (of the analysed composition) to re-
construct an average magma very closely allied to the average
composition of the olivine-gabbro-diabases of Gran, or perhaps
slightly more basic. To establish this calculation I still need
several analyses ; a preliminary trial has shown the approximate
proportions, and these proportions seem to ajrree with the obser-
vations made in the field as to the extension of the different kinds
of rock on tho hill-top. When, in a monograph on these basic rocks,
I can present, as I hope to do, the exact calculation, founded on
a sufficient number of analyses, showing that x parts of the analysed
basic olivine-gabbro-diabnse of Brandberget mixod with y parts
of hornblendite, z parts of pyroxenite, and w parts of augite-diorite
(all of analysed varieties from Brandberget) give about the average
composition of the olivino-gabbro-diabase above calculated from the
analyses of rocks from Brandberget, Solvsberget, and Digmes, then I
hope to have proved that all the various kinds of rock from Brand-
berget must be considered as products of differentiation from a .
i
Digitized by Google
Vol. 50.] BASIC ERUPTIVE BOCKS OK GRAN. 33
magma only slightly different from the before-mentioned average-
magma, which, for the sake of brevity, I will designate as magma O.1
If the average composition of the rocks of Brandberget is,
possibly, a little more basic than the average composition of the
bosses between Brandberget and Dignres taken altogether — that is. is
more basic than magma O — this is certainly not the case with the
boss of Solvsberget. The rocks of Solvsberget on the whole
undoubtedly possess an average composition conforming very
closely to that of magma 0. Besides, we have found that the bulk
of the eruptive rocks on Solvsberget is represented by an olivinc-
gabbro-diaba8e of nearly the average composition. Nevertheless
I have also observed on Solvsberget a series of differentiations of
magma O, which are, on many accounts, of much interest.
Moreover, on Solvsberget I have found the samo pyroxenites as
on Brandberget, although to a more limited extent, namely on the
western and south-western side of the hill, as contaet-facies ; but
I have not observed any hornblendite.
On the eastern end of the boomerang-shaped boss, where the
tectonic relations have been quite exceptional, a peculiar differen-
tiation has taken place. By this differentiation along the contact
there is separated out a magma which has consolidated as labrador-
porphyrite.
The chemical composition of this labrador-porphyrite has not
yet been determined by analysis, but it is assuredly not very
different from that of the labrador-porphyrite of Hukcn, north of
Christiania, where this rock is spread as an old sunken lava-
flow over large areas. An analysis of the Huken rock, made in the
laboratory of Herr L. Schmelck, gave :
SiO, 47TiO
TiO, 3 02
Al.,0, 17 f>7
Fe.O, 724
Feb MW
MgO 331
CaO 6 19
Nap 3H0
K,U 3-28
tt,0 1-70
CaCO, 0»»8
Ca^b, 1-00
10017
The difference between this and magma 0, as will be seen, is
quite unimportant, because the composition for most compounds
lies between magma O and the composition of the olivine-gabbr«>-
di abase from Dignajs. However, a slight differentiation has
taken place, the mixture of the labrador-porphyrite being poorer
1 As aboT© mentioned, the average composition of the rocks of Brandberget
seems to be a little more basic thun the average of the more southern
occurrences.
Q. J. G. S. No. 197. b
Digitized by Google
PROF. W. C. BRoGGER 02? THE
[Feb. 1894,
in magnesia and lime, and richer in alumina and alkalies, than the
chief rock of Solvsberget (see p. 19). As is well known, the con-
ditions of crystallization for pyroxene and labradorite overlap in
certain magmas of gabbro and diabase-composition. We find, there-
fore, that in one case the plagioclase has crystallized essentially
before the pyroxene (ophitic structure), in other cases the relation
lias been the reverse (as in several typical gabbros). A very slight
alteration of the physical conditions (temperature and pressure)
along the cooling margin on the eastern side of Solvsberget must
have been sufficient here to cause an increased diffusion of the
plagioclase-forming compounds in the magma to take place towards
the contact; while under the altered conditions the labradorite
would have crystallized more ea*ily than the pyroxene. The magma
thus separated by a slight differentiation has then, on its subse-
quent consolidation, been cooled in such a manner that it has
assumed a porphyritic structure, and consequently has left a labrador-
I>orphyrite. This — in comparison with the main type on Solvsberget
— more acid rock is undoubtedly a later product of the magma, for
we find, at Bjerget for instance, that the labrador-porphyrite is full
of angular fragments of tho common olivine-gabbro-diabase of
Solvsberget, developed as a characteristic eruptive breccia.
In the close vicinity of Solvsberget there also occur dykes of
augite-porphyrite, with the same mineral composition and structure
as the lava-flows so abundant in the neighbourhood of Holmestraud,
etc., which are the oldest effusive rocks of the Christiania region,
and undoubtedly an outflow of the same magma as the basic rocks
of Gran. These augile-porphyrites show only very slight, if any,
difference in their chemical composition from magma (). The above-
mentioned dykes are not then chemically differentiated in relation
to the main rock-type of Solvsberget : they merely represent good
examples of the influence of differences in pressure and temperature,
etc., on tho products of crystallization. For the same magma,
which by cooling slowly in the boss as an abyssal mass is con-
solidated to cugranitic olivine-gabbro-diabase, cooling more rapidly
in dyke-fissures and on the surface as lava-beds, has left augite-
porphy rites, quite different in structure and mineral composition.
Examples of this kind arc now well known from a multitude of
localities ; one need only call to mind the Monte Amiata in Tuscany,
so well studied by tho late F. It. Williams, whose premature decease
we all mourn, and the magnificent monograph on the rocks of Electric
Peak and Sepulchro Mountain published by J. P. Iddings. In the
Christiania region examples of such relations are numerous.
The differentiations in the laccolite of the Viksfjeld show, in
the mnin, similar relations to those just described ; more acid
quartziferous augite-diorites are here frequent as the latest products
of differentiation. Time unfortunately does not allow of a detailed
description.
Digitized by Google
Vol. 50.]
BASIC ERUPTIVE ROCKS OF GRAN.
35
VII. Conclusions.
In the preceding pages I have tried to set forth, in a brief rlmmc,
a series of examples illustratiug the fact that the compositions of
eruptive rocks are sensible functions of the composition of the
mother-magma, and of the manner in which this latter has been
differentiated during cooling and diminution of pressure.
A magma of a composition closely allied to that above desig-
nated as magma 0 has, so far as I can at present form an
opiniyUj. been the oldest product of differentiation from tho general
ma^iaa-reservoir of the sunken tract defined by me as the Chris-
tifuja.tjrcgion, this magma-reservoir itself having been, perhaps, a
jiroUn^^flillerjentiation, in yet mo^e remote ages, from a universal
earth-imigma. ' Magma 0 was then, if my deductions be correct,
the source of all the different basic eruptive rocks in the Christian ia
region, especially also of the bosses, dykes, and sheets in Gran and
the neighbouring parishes, and their equivalents, the effusive basic
rocks of the series of augite- and labrador-porphyrites, etc.
In studying these rocks we have found examples of general
relations of some importance : —
(1) That we can, with great certainty, connect a scries of dif-
ferent dyke-rocks (camptonites and bastonites) with an exactly
defined boss-rock of, per se, different mineralogical and chemical
compositions.
Similar connexions are known from other regions. I need only
call to mind the connexion of Limprophyric minettes with granites,
often pointed out by our great master in general petrology, Prof.
Kosenbusch, and recently so well described by Marr and Harker.1
But in the present case I think that a connexion of this kind has
been more definitely proved than in previously published instances.
(2) That the dyke-rocks in question — the camptonites and the
bostonites — have probably been produced by differentiation in an
abyssal magma of a certain chemical composition, which we have tried
to calculate exactly from sufficient data. A calculation of this kind
has not, so far as the writer is aware, been previously published.
(3) That the calculated basic mother-magma, or magma 0,
has partly consolidated in the bosses in Gran without being differ-
entiated," as olivine-gabbro-diabases (type: Solvsberget) , and has
partly been differentiated into camptonites and bostonites, but
partly also into other kinds of rock : t. e. into pyroxenites, horn-
blendites, and more acid augite-diorites, etc. We have, then, here
an example of the remarkable fact that one and the same may ma
undtr different conditions has been differentiated in different ways,
and separated out so as to form different groups of rocks with different
chemical compositions in the individual members of each group ; we
must above all remember that here is a question not only of dif-
ferent mineral-aggregates, but also of different chemical compositions.
It is thereby proved that the differentiation of a magma depends
not only on the given chemical composition, but also essentially on
1 Quart. Journ. Geol. Soc. toL xlrii. (1891) p. 266 ; Geol. Mag. for 1802. p. 199.
D 12
Digitized by Google
36
TROF. W. C. BROGGEB OK TUB
[Feb. 1894,
the physical conditions under which the differentiation takes place.
The ' kern 1 hypothesis of ltosenbuscb, in the form given by that
author, does not fit in with these deductions.
(4) The observations here described probably further show the
inverse case, that the same group of differentiated rocks (in the
present case, caniptonites and bostonites) can be produced by separa-
tion from mother-magmas of quite different chemical composition. In
our case these dyke-rocks have been derived from an olivine-gabbro-
diabase magma ; in other instances we know that the same rocks
are connected with nepheline-syenites (augite-sycnites?), and have
probably in those cases been differentiated out of a nephelinc-
syenitic(augite-syenitic ?) magma. This being so, we have another
fact which does not agree with the * Jcem 1 hypothesis.
(5) I have endeavoured to prove that the inferred differentiation
has been determined by, and is dependent on, the laws of crystalli-
zation in a magma in so far as the compounds, which on given con-
ditions would first crystallize out of the magma, must have diffused
to the cooling margin, and in this way have produced, in the
contact-stratum, a peculiar chemical composition iu the still liquid
magma before any crystallization took place.
By tho pressing-up in this manner of the differentiated masses to
a higher level at lower temperature and pressure, or by continued
cooling along the contact-margin with subsequent crystallization,
there have then been produced different kinds of rock of peculiar
chemical composition, miueralogical constitution, and structure.
The sequence of eruptions from a common magma-basin (magma-
reservoir) must therefore, to a certain extent, be parallel with
the sequence of crystallization in the corresponding kinds of
rock. Many years ago, I tried to prove that this opinion is
really confirmed by my observations on the rock-succession in
the Christiania region, which closely conforms to the sequence of
crystallization in the corresponding abyssal rocks in this * eruptive
province/ A series of confirmatory examples is known from the
literature of other countries, from the British Islands by the
excellent publications of Sir Archibald Geikie, Messrs. Teall,
JDakyns, and othor authors. The examples are roally so numerous
that they seem to represent a general law. No doubt in many cases
the rock- sequence in different 4 eruptive tracts ' does not appear to
agree with this empirically deduced law. But that does not prove
that the law has no existence ; it only shows that other conditions
besides those above-mentioned aro of importance for the determi-
nation of the eruptive sequence. A discussion of the great number
of different possible cases (for instance, the hypothesis of Iddinga
as to the eruptive sequence, etc.) would on this occasion lead us too
far. Here my intention has been simply to present a series of ob-
servations from a single locality, in which tho genetic relations
between the different kinds of rock seem distinctly to favour the
opinion of a conformity between tho sequence of crystallization and
that of differentiation.
Digitized by Google
Vol. 50.]
BASIC ERUPTIVE ROCKS OF GRAN*.
37
80 far, I think, we are on safe ground : I would expressly point
out that I have not discussed the primary reason for a differentiation
of the above-described nature, whether this is to be sought for in
8orer/s principle, in the effect of chemical affinity, or in other causes.
That in many cases also the principle of Guy and Chaperon, the
commencement of crystallization and the sinking to the bottom
of the crystallized masses, as well as a subsequent re-melting
of such early crystallizations, may have performed a part in the
processes of magma-differentiation is quite possible. Wo move here
in a maze of hypotheses.
But the differentiation itself is not a hypothesis ; it must now bo
reckoned with as a solid fact of great importance. The same law,
which in a narrow dyke-fissure has produced a differentiation
along the more rapidly cooling dyke-sides, has, operating on a
larger scale in the magma-basins in the earth's crust from which
eruptions of a local volcanic centre originate, differentiated out
the pressed-up secondary magmas, so that they have succeeded
each other in a regular order. Finally, the same law has perhaps
determined the particular composition of the magma of each separate
magma-basiu by differentiating tho same out of the pristine liquid
magma upon which, by the cooling of the earth, the solid crust was
deposited.
Discussion.
The President said it was of advantage to the Society to have
communications of this kind from distinguished foreign geologists.
The paper reminded him of one by Dakyns and Teall, published
in Quart. Journ. vol. xlviii. (1892). Tho basis of this philosophy
appeared to lie in the determination of the order of crystallization by
the microscope. Tho theory must be supported by very clear field-
evidence, otherwise it would remain a mere speculation.
Prof. Judd said that the Geological Society of London must hail
with pleasure the fact that Prof. Brogger had chosen their Journal
as the means of communication to the world of a memoir of such
value and interest. Prof. Brogger's contributions to all branches
of geological and mineralogical scieuce are so large in amount and
invaluable in character that his claims on the attention of geologists
are unrivalled. The speaker especially referred to the novelty and
interest of the Author's views concerning the mode of separation
of magmas, and to his suggestion that the nature of contact-
metamorphism depends on the character of the erupted rock, as
well as on the materials through which it has been ejected.
Gen. M'Mahox remarked that the Author appeared to hold the
view that the differentiation of a magma into a continuous series of
rocks, ranging from those of a more basic to thoso of a more acid
type, depended on the laws that determine the sequence of crystal-
building — that is to say, that the more basic minerals are those
which first crystallize out from a magma, the remaining minerals
Digitized by Google
38
BASIC ERUPTIVE ROCKS OF GRAN — DISCUSSION. [Feb. 1 894,
following in the order of their basicity. Further, the Author held
that the more basic rocks were older — that is to say, were erupted
before the more acid ones; the latter, as Mr. Teall explained,
forming dykes cutting the more basic rocks. If this were so,
it would follow that, as the differentiation in the general magma
progressed, the basic material would sink to the bottom and the acid
portion of the magma would remain at the top. When pressure was
exercised on a fluid, or viscid, magma differentiated into layers in
the way supposed, and eruptious began to take place, one would
have expected the acid top layer to have been the first to have
issued from the cauldron. It was a pity that the Author was not
present, as he (the speaker) would very much like to learn by what
physical process the deeper-seated and more basic portions of the
still fluid magma were first erupted.
Prof. J. F. Blake and Mr. W. W. Watts also spoke.
Digitized by Google
Vol. 50.]
PICRITF AND ASSOCIATED ROCKS AT BVRNTON'.
30
4. On a Picrite and otiier associated Rocks at Barnton, near
Edinburgh. By Horace W. Moxckton, Esq., F.L.S., E.G.S.
(Road December 6th, 13U3.)
The Barnton Branch of the Caledonian Railway leaves that Com-
pany's Edinburgh and Leith line immediately north of Craiglcith
Station, opposite to Sir James Maitland's great Craiglcith Quarry.
The Barnton line lies almost entirely on Sir James's property, and
I have to thank him for assistance in collecting the facts I now
record. On our last visit to the locality we first inspected a trial pit,
east of the old railway and close to it, a little north of Craigleith
Quarry. The section was as follows : —
1. Surface-bed, with a few largo boulders.
2. Thinly-bedded sandstone, about 12 feet.
3. Sbaly beds, with an easterly dip of 1 in 4.
The first cutting on the new line is about | milo from the
junction at Craigleith. It is 19 feet deep and entirely in Boulder
Clay. At from 3 to 4 feet below the top of the cutting there is a
remarkably oven line of very large boulders, and in one place I noted
below them a patch of yellow sand 2 feet thick. The rest of the
sides of the cutting is formed of black clay, full of small stones.
More Boulder Clay is shown between House o' Hill and Dry law,
but it is not till we reach Barnton Park that we find a section
showing the solid geology. In the first cutting in the park the
beds of the Calciferous Sandstone Series are seen dipping westward
at an angle of about 30°, and as I began my examination at tho
eastern end they are hero described in ascending order.
Diagram-Section on the Barnton Railway in Barnton Pari-.
10 98765*9 3 X
1 1 . Dolerite.
10. Picrite, through which
run veins of basalt.
9. Indurated shale.
8. Igneous rock.
7. Indurated shale or
'calm.'
6. Igneous rock, 1 foot
( ra ica-porphy rite).
5. Indurated nhale.
4. Igneous rock, 12 feet
(mica-porphyrite).
3. Indurated shale.
2. Black shale, with
veins of calcite,
1. Thinly-bedded sand-
stone.
Much of the shale of beds 3, 5, and 7 is of a whitish colour and
very hard, of the kind locally termed 4 camstone ' or * calm.' A
similar rock is, I believe, quarried in Corstorphine Hill.
Associated with this shale are some beds of igneous rock. Micro-
sections have been made from bed No. 4 and from bed No. 0.
Digitized by Google
40
MR. H. W. MOSCKTOX ON A P1CKITR
[Feb. 1894,
They are very similar one to another. Thero are a few porphyritic
crystals of a green mineral which may to some extent replace oliviue ;
but I think that in most cases it more probably replaces augite,
The shape of the crystals is not quite that of olivine, and in the
slide from bed No. 4 there are one or two crystals not so much
altered as the rest, and one of them seems to extinguish at an
angle of about 45°, and is, I think, certainly augite. Perhaps some
of these green crystals, especially some of those in the slide from bed
No. 6, may be alteration-products after bastite. Some of them
are bordered with small flakes of brown mica (no doubt secondary),
and there is a great deal of brown mica in the groundmass, the
flakes of which are minute in bed No. G, while in bed No. 4 they
are often 0*006 inch long. There are Bomo small crystals of augite,
and a great deal of very much altered pi agioclase- felspar in small
lath-shaped crystals. Many zeolites occur all over the section,
and there are a few crystals which I think may bo epidote.
At one spot in the micro-section from bed No. 6 there is a very
pretty group of zeolites at the base of the igneous rock, whore it
rested on the shale of bed No. 5. It is not veiy easy to name this
rock. Perhaps • mica-porphyrite ' is the most appropriate appellation,
although the rock can scarcely be said to contain porphyritic felspar :
it is somewhat nearly allied to kersantite. Tho mica-porphyrite
lies very evenly between the beds of stratified rocks, but the great
induration of the shales above and below it shows thut it is probably
intrusive.
[When I sent this paper to the Society I was not aware that the
cutting had already been described by Mr. John Henderson and
Mr. J. G. Ooodehild.1 The former of these authors mentions tho
igneous rock which I have called mica-porphyrite as » intrusive
greenstone.' The picritc and overlying basalt he describes as a mass
of greenstone dipping conformably with the shales, and having an
apparent bedding and dip to the west. This apparent bedding, duo
to planes of jointing, is very marked. Mr. Goodchild points out
that a portion of this mass of greenstone is picritc : he does not
deal with the mica-porphyrite.]
The picrite is No. 1 0 of the section (see p. 39), and it forms the
sides of the cutting for some distance. The greater portion is soft,
and granular, but hard parts may bo found here and there. The
planes of jointing are fairly parallel to the stratification of the shales,
etc., which underlie it.
Under the microscope it is seen to be composed of: —
(1) Serpent ini zed olivine, in more or less rounded grains of very
different diameters — one of medium size measures 0*08 X 0*04 inch.
The olivine has been altered into a mineral of a brilliant yellow
colour, with a somewhat parallel fibrous structure, and round the
edges of the grains a further alteration into a bluish-green and more
markedly fibrous mineral has taken place. This mineral is dichroic,
changing from bluish-green to yellow. Sometimes, especially
1 Trans. Oeol. Soc. Edinb. vol. vi. part v. (1893) pp. 297, 301.
Digitized by Google
Vol. 50.]
AND OTHER ASSOCIATED ROCKS AT BARXTOX.
41
among the smaller grain*, the -whole or nearly the whole grain has
been changed into the green mineral. The extinction-angle of these
minerals may be a little oblique, but of that I am not quite sure.
In any case there cau be no doubt that they aro alteration-products
of olivine. Most of the grains contain scattered specks of iron
oxide.
(2) Awjite of a light pink colour, in grains of most irregular
shapes, fairly well preserved and sometimes more than inch in
length. The larger grains contain enclosures of the altered olivine,
microliths, etc.
(II) Pehpar. A very few lath -shaped crystals ; tho largest mea-
sures 0-04 x 0*007*5 inch.
(4) Mica in flakes, of which one of an average size measures
0 015x0 01 inch. They are orange aDd yellow-brown in colour,
and are dichroic.
(5) Iron Ou-ide, in grains and granules down to fine dust,
scattered through the altered olivine. It does not occur in tho
augite, except in connexion with altered oli vine-enclosures.
There is in places much interstitial matter of a turbid white
appearance, which may be, at least in part, altered felspar.
In pi. xxvii. of the 'Mineralogie Micrographiquo'of MM. Fouque
and Michel-Levy a micro-section is figured of a rock in which
alteration has taken placo, somewhat like tho alteration of the
olivine in the Barnton picrite. The crystals in the French rock
are, however, more regular and clearly defined than the crystals of
altered olivine in the Barnton rock — which are not unlike the
serpentinous pscudomorphs alter olivine in tho micro-section of tho
Menheniot picrite figured by Mr. Tcall.1
In one illustration of the Inchcolm picrite by the same author2
a crystal is shown, surrounded by small flakes of hornblende, which
is not unlike the green crystals in bed No. 6 of the section here
described, in which, however, the peripheral mineral is brown
mica. It will be remembered that the island of Inchcolm lies in
the Firth of Forth, \\ miles north of the Barnton railway-cutting.
I submitted a micro-section from the Barnton picrite to Prof.
Bonney, F.K.S., and he has very kindly furnished mo with the fol-
lowing remarks on its affinities with other picrites : — "The change
of the olivine here exhibited is not the one so usuallv seen. It is
more regular, more uniform, and more analogous to the change of
the enstatite-group. We have it in the Porthlisky picrite, tho
Menheniot picrite (but here are some other peculiarities in the net-
work of microliths), traces of a similar structure in the Duporth
rock (here, however, I suspect an altered bastite), also in a picrite
boulder from near Liskeard (possibly connected originally with
Menheniot). I have, however, scon it in some true serpentines.
"The Barnton rock comes in many respects very near to the
1 ■ Brit. Petrogr./ 1888, pi. ii. fig. 2.
2 ItAd. pi. vii. fig. 1.
Digitized by Google
42
MR. H. W. MOXCKTON ON A PICRITK
[Feb. 1894,
picrite of Inchcolm, but the latter rock is less altered.1 I have,
however, in my collection specimens which show more complete
change and so approximate more closely. After looking through
a considerable number of specimens of picrite in my collection I
have no hesitation in saying (1) that the Barnton rock is a genuine
picrite ; (2) that it is most probably an offshoot from the samo
magma as that which supplied the Inchcolm rock. It differs from
the Bathgate rock."a
Through the bed of picrite run veins of a very different
character. The vein-rock is noncrystalline and consists of : —
(1) Aitgite, well preserved, white, brown, and pinkish in colour,
in large crystals.
(2) Phujioclase-ftlspar, in large crystals showing twin-striation.
Originally the plagioclase formed a large proportion of the
rock, but it is now to a great extent changed into a turbid
white mineral.
(3) A greenish-yellow, secondary mineral, which has scarcely the
shape of olivine — it may be bastite, but is not unlike the
green mineral found in beds Nos. 4 and 6 (mica-porphyrite),
and possibly it may be a peculiar variety of augite.
(4) Thcro are several brown and greenish dichroic crystals. Some
of these are apparently mica, some are hornblende. About
others I feel considerable doubt — possibly they may be an
actinolite.
(5) Iron oaride is fairly abundant.
(6) Zeolites occur, as in the rock of bed No. 6.
Mr. John Henderson described one of these veins, probably the
same as that from which I brought away a specimen, as a vein or
thin dyke cutting the * trap ' and passing obliquely from below to
the surface.3 Mr. Goodchild considers them to be segregation-veins.
Perhaps they may be described as dolerite, more especially as they
bear a strong resemblance to the igneous rocks of No. 11, which
overlies the picrite and is certainly an ophitic dolerite.
A reference to the Geological Survey Map (Sheet 32, Scotland)
will show that the Corstorphine Hill mass of igneous rock projects
northward towards the Forth, and tho cutting which I am de-
scribing is situated nearly at the northernmost end of the patch
mapped. Accounts of the igneous rock of Corstorphine Hill are given
by Mr. Allport and Mr. Teall,4 and their descriptions agree well
with a micro-section cut from a specimen which I obtained in Sir
James Maitland's large quarry, south of the Queensferry Road,
» See A. Geikie, Trana. Roy. Soc. Edinb. toI. xxix. (1879) p. 507 ; also
Teall. op. supra cii.
3 A. Geikie, op. supra cit.
3 Tran*. Geol. Soc. Edinb. vol. vi. part v. (1803) p. 209.
4 Quart. Journ. Geol. Soc. vol. xxx. (1874) pp. 5o7-*>58: 'Brit. Petroirr '
1888, p. 190.
Digitized by Google
Vol. 50.]
AXD OTHER ASSOCIATED ROCK 8 AT IURNTOX,
43
and about 2£ furlongs from tho 4 picrite '-cutting on the Barnton
Railway.
My Corstorphine Hill specimen resembles to a certain extent tho
specimen from the vein running through the picrite which has just
been described. In both cases there are augite-crystals particularly
well preserved, and in both the felspar is largely replaced by some
other mineral; but whereas in my railway-cutting micro-section
some felspar-crystals are seen showing twin-striation very clearly,
there is not one in the Corstorphine Hill micro-section — so complete
is the alteration of the felspar in that rock. Mr. Allport, however,
mentions that in micro-sections from some parts of Corstorphine
Hill a little plagioclase is preserved. The brown dichroic mineral
of the rock from tho railway-cutting seems absent from the Cor-
storphine Hill specimen. I am not certain as to pscudomorphs
after olivine in the railway-cutting specimen, but they undoubtedly
occur at Corstorphine Hill ; and there are some pale-green aggregates
of a fibrous or radial structure, forming plates into which the felspar-
crystals ponetrate as in an ophitic dolerite. Probably they represent
a pyroxene, now replaced by actinolite and serpentine.
The remaining cuttings on the Barnton Railway showed Boulder
Clay, the boulders being few, but largo.
In conclusion, I must express my indebtedness to Prof. Bonney
for kindly looking at the micro-sections and for assistance generally.
He allows mo to say that he agrees with the determination of the
minerals mentioned in this paper.
Disctssion.
Sir Jambs Maitland said that ho had on several occasions visited
the section described, and had seen the paper from which some
extracts had just been read. The ' calm ' or indurated shale in
connexion with the intrusive igneous rocks at Barnton was very
like that which occurred to a depth of 36 feet in a similar relation
to the basalts of Sauchie (Stirling). Other things of interest were
found in the Barnton cutting : for instance, a heap of recent sea-
shells was cut through about the 170-feet level, the same level as
that of tho largo boulders resting on patches of sand described in
the paper ; and a short distance west of Barnton he had found good
oil-shale forming practically the top of the solid geology, and covered
with over 100 feet of alluvium. The six-inch map hung on tho
screen was an old one, and did not show an intrusive sheet of basalt
to the east and north of Craigleith, which separates that famous
quarry from an excellent bed of building-stone proved during the
last month to a depth of 45 feet.
Digitized by Google
44 MESSRS. W. R. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 894,
5. The Purbeck Beds of the Vale of Wardour. By the Rev. W.
R. Andrews, M.A., F.G.SM and A. J. Jukes-Browne, Esq.,
B.A., F.G.S. (Read December 6th, 1893.)
Contents.
Psge
I. Introduction 44
II. General Structure of the District 44>
III. The Lower Purbeck Group 48
IV. The Middle Purbeck Group A3
V. The Upper Purbeck Group 5U
VI. General Conclusions, aud Comparison of Dorset and Wiltshire
Purbecks 03
VII. List of Fossils 68
Map 47
I. Introduction.
Although the Purbeck Beds of the Vale of Wardour have been
noticed by many observers, and portions of thorn have been
described by many writers from the time of Fitton downwards, no
complete description of the whole series has yet been attempted,
and a connected account of the Wiltshire Purbecks seems therefore
to be a desideratum in geological literature.
Fitton gave some account of them in his classical memoir
* On the Strata between the Chalk and the Oxford Oolite,' published
in 183C),1 mentioning quarries at Dallard's Farm, Dashlet, Chicks-
grove Mill, and Wockley ; but since his time the Wockley quarry
has been cut back, so as to expose the beds which were then only
visible at Chicksgrovc. Ho mado no attempt to establish any
succession, and thought the total thickness of the scries was not
more than GO feet.
The Rev. P. B. Brodie, in 1845, published a little book entitled
* A History of the Fossil Insects in the Secondary Rocks of Eng-
land,' in which he gave some description of the Purbeck Beds of
the Vale of Wardour, and especially of two beds of liraestono, ono
of which he called the * Isopod Limestone,' because it contained
Arch<roni8cu8i and the other the 4 Insect Limestone,' from the
abundance of insect-remains in it. Unfortunately, his reference
to localities was not very explicit, but it is certain that the quarries
** not far from the village of Dinton," where ho saw these lime-
stones, are not now open, and the details he gave were so different
from the Dallard's Farm section described by Fitton that they could
not possibly represent the same beds.
In 1850 Edward Forbes read a paper at the meeting of the
British Association at Edinburgh on tho Purbeck series of Dorset, J
which he proposed to divide into Lower, Middle, and Upper groups,
according to the prevalence of certain species of Cyprids. This paper
1 Trans. Geol. Soc. ser. 2, vol. iv. pp. 103-388*.
2 Subsequently published in Ediub. New Phil. Journ. vol. xlix. pp. 391-3&L
Digitized by Google
Vol. 50.] 02? THE PURBECK BEDS OF THE VALE OF WAHDOUB. 45
induced Mr. Brodie to revisit the Vale of Wardour, and in 1854 1
he published a short account (but more connected than his previous
one) of the Wiltshire Purbccks. He stated that the Upper division
is wanting, but that the Middle and Lower groups are tolerably
well-developed ; he gave a descending section drawn up by the
Kcv. O.Fisher, in which the demarcation between Middle and Lower
Purbeck was fixed at a certain dark clay overlying a limestone
which contains Cijpris purbeckensti. Mr. Fisher also for the first
time recognized the ' Cinder-bed ' in the Valo of Wardour ; but the
Wockley section was not mentioned, and no attempt was made to
estimate the total thickness of the Wiltshire Purbecks.
The district was mapped by the Geological Survey during the
years 1852, '53, and '54, the map (sheet 15) being issued in 185(>;
but no explanatory memoir has ever been published, nor did the
surveyor ever publish any account of his observations.
A detailed account of the Middle Purbeck Beds exposed in the
railway -cutting south of TefFont was written by one of us in 1881,
to accompany Mr. Etheridge's description of a new species of
Triyonia from the * Cinder-bed' of that locality.2 The four
lowest beds of that section were grouped as Lower Purbeck, but it
was subsequently found that they really belonged to the Middle
Purbeck, the base of that division not being exposed in the
cutting.
A general account of the geology of the Vale of Wardour was
compiled by the same writer, and printed in the Proceedings of the
Dorset Nat. Hist. & Antiq. Field Club for 1883, vol. v. pp. 57-08.
In 1890, while one of us was engaged in examining the Creta-
ceous rocks of Wiltshire, we jointly surveyed the eastern end of
the Vale of Wrardour, with the special object of separating the
Purbeck from the Wealden, and of ascertaining whether any
Vectian Sand intervened between the latter and the Gault. The
work was done on the six-inch Ordnance maps, and the result of
our survey was to convince us that not only wore all these formations
present, but that a considerable thickness of strata lay between the
recognized Middle Purbeck and the beds regarded as WTealden.
These strata seemed to be so clearly an upward continuation of the
Purbeck series that we felt justified in referring the greater part of
them to the Upper Purbeck group, a division which had not pre-
viously been recognized in the district. The existence of these Upper
Purbeck Beds was announced in the Geol. Mag. for 1891, p. 292,
and in that note we expressed our intention of preparing a more
detailed account of the Purbeck series. The present communica-
tion is the fulfilment of that intention.
Tho correlation of the beds exposed in the various quarries and
cuttings in the central part of the Vale is by no means an easy
task, for though easterly dips are prevalent, and higher beds come
in gradually towards the east, yet thiB general inclination is so
1 Quart, Journ. Geol. Soc. vol. x. p. 475.
1 Ibid. vol. xxxvii. p. 216.
Digitized by Google
45 THE PURBBCK BED3 OP THE VALE OF WARDOUR. [Feb. 1 894.
interrupted by cross-rolls, and apparently also by small faults, that
the relative position of a section is no guide to its real geological
position. The consequence is that, unless some particular bed can
be identified with one seen elsewhere, it is very difficult to refer an
isolated exposure to its proper place in the series. There are a few
such sections about the position of which we are still uncertain,
but we think the beds seen in them will prove to be only the
equivalents of some of the strata described in this paper.
We are indebted to Prof. T. Rupert Jones, F.K.S., and Mr. C.
Paries Sherborn for identifying the Cyprids which we collected,
and to Messrs. G. Sharman and E. T. Newton, F.R.S., for naming
tome of the mollusca.
II. General Structure of the District.
The main features of the geological structure of the Vale of
Wardour are well known. It will suffice to say that the Purbeck
Beds come in at the eastern end of the Vale, because an easterly
dip was imparted to the Jurassic system before the superposition of
the Cretaceous strata upon it. The uncovering of the Purbeck Beds
at this locality is due to the denudation which has taken place
along the axis of a post-Cretaceous anticlinal flexure.
The axis of this anticlinal does not, however, coincide with the
lowest or central part of the valley, but runs nearly due east-and-
west through Lady Down and Teffont Evias, its northern limb
being much shorter and more steeply inclined than its southern
limb. Moreover, the pre-Cretaccous dip of the Jurassic strata was
not due east, but nearly south-east ; neither was this south-easterly
dip a steady and continuous one, but interrupted by cross-rolls and
faults, so that the present disposition of the outcrops results from
the interference of three distinct Bote of disturbances. The conse-
quence of this interference is to produce a number of divergent
dips, and to make the mapping of the subdivisions of the Purbeck
series rather complicated.
Although the beds are horizontal on the top of Lady Down,
they slope thence rapidly south-eastward, and the base-line of the
Middle Purbeck group falls through 200 feet in less than two miles,
owing to the combined effect of the original dip and the inclination
of the southern limb of the post-Cretaceous anticlinal.
The axes of the pre-Cretaceous flexures Btrike from north-west to
south-east, and going from west to east the following flexures may
be noticed : —
(1) The anticlinal of the Chilmark Valley, which brings up the
Portland Beds near Chilmark, but seems to die away southward, or
is masked by the steep south-easterly inclination of the axis.
(2) A synclinal bringing in what seems to be the base of the
Upper Purbeck group in a small cutting on the railway near
Daslett Farm.
^ Digitized by Google
48 MESSRS. W. R. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 89 4,
(3) An anticlinal corresponding with the Teffont Valley, and
bringing up the Lower Purbeck Beds into the cutting near Teffont
Mill, where they are much disturbed and even contorted.
(4) A synclinal, with probably a fault, between the first and
second cuttings on the line west of Dinton Station.
(5) An anticlinal seen in the first cutting west of Dinton Station.
The sketch-map on p. 47 is reduced from the six-inch maps on
which we recorded our observations, and we have ventured to draw a
complete boundary-line between the Lower and Middle Purbeck
Beds, although it should be stated that we did not trace this over
the ground, but drew it in afterwards from a consideration of the
data collected : these are, however, sufficiently numerous to prevent
any serious error.
The complete discordance between the Purbeck Beds and the
Lower Cretaceous series, including the Wealden, is clearly shown by
the manner in which the base of the latter passes across the anti-
clinal of the Chilmark Valley without being affected thereby.
III. The Lower Purbecx Group.
There are two localities in the Vale where the junction of tho
Portland and Purbeck strata can be examined, namely Chilmark
and Wockley ; but, although the two quarries are only two miles
apart, the beds seen in the one are so different from those seen in
the other that it is hardly possible to compare the two sections.
It will be convenient to begin with the Chilmark section as being,
in some respects, tho simplest. This is shown in the higher quarry
on the eastern side of the Chilmark Valley, and is as follows : —
Feet. Inches.
' Shaly marl, with lenticular beds of soft limestone, bed-
ding wavy 2 0
Yellowish tufaceous limestone 0 8
Soft, white, chalky limestone about 1 0
Stiff grey clay, containing pebble* of whitish limestone
and many pieces of wood ; base uneven : from 1 foot to 1 8
^ Tufaceous marly limestone, very soft in places and ir-
i ■ • l l i i* v I*
if
J? ■<
PL, J
regularly bedded : varies from 5 feet to 6 6
Yellowish oolite, witli lenticular layers of browu oolitic
flint at the top 1 3
Course of clear brown, glassy flint 0 3
Hard, compact, tufaceous limestone 4 0
Soft, dark grey, marly clay : purplish in places 0 3
Firm yellowish oolite iu thick beds, the upper surface
rather uneven seen for 10 0
White chalk, with flints, in quarry below 24 0
In this section there is no decided break or strong line of division
between the Portland and Purbeck Beds. The oolite with the
curious oolitic flint is very like that which is classed as Portlandian ;
but it seems reasonable to regard the tufaceous limestones as belong-
ing to Purbeck rather than to Portland time, and as they contain only
a few small bivalves resembling Cyrenas we have so classed them,
taking the dark clay-band as the basement-bed of the Purbeck series.
The grey clay which rests on the upper tufaceous limestone is a
remarkable bed, and appears to be tho relic of an actual terrestrial
i
Digitized by Google
Vol. 50.] ON TEB PURBECK BEDS OP THE TALE OP WARDOUR.
49
surface. An upright and rooted stump of a tree (exogenous) was
found in it, the stem standing about 6 feet high, and a portion of
this is still preserved at the quarries ; a specimen of Cycadeovle*
microphyfla was picked up on the talus just below, and doubtless
came from this bed. Fragments of wood arc common in it.
We find that Prof. J. F. Blake has given a section of this quarry
which differs little from the above, but he remarks that the section
does not agree with Fitton's account. We cannot find, however,
that Fitton gave any account of this section, which was probably
not exposed at the time he wrote, for he only observes that
" among the loose matter at the top of these quarries is botryoidal
carbonate of lime, passing into compact freshwater limestone, like the
4 Cap ' of Portland." (Trans. Geol. Soc ser. 2, vol. iv. 1836, p. 255.)
We think that Prof. Blake must have made some confusion
between Chilmark and Chicksgrove, for he mentions both places in
connexion with the same section. It was Chicksgrove Mill quarry
which Fitton described in detail, and the slab of stone referred to
by Prof. Blake which is preserved at the Museum of Practical
Geology in Jermyn Street, and is supposed to show the junction
of marine Portland with freshwater Purbeck, must also have come
either from Chicksgrove or Wockley. The succession at these two
localities is substantially the same, but is very different from that
of Chilmark. The Chicksgrove section is now obscured and
weathered ; the quarry at Wockley, however, is still worked, and the
following succession of beds was there displayed in 1890 : —
Feet. Inches.
f Hard, flaggy, oolitic limestone, with Cyprids 1 t>
Soft marly stone passing down into argillaceous marl 1 6
Sandy brown clay 0 3
Grey oolitic stone with Cyprids 0 4
Laminated, grey, sandy marl passing down into soft, yellow,
eandy marl ; Cyprids 1 8
Layer of brown clay 0 2
Hard tufaoeous limnstone 1 0
Soft, white, silty marl, interlaminated in the upper part with
layers of brown sandy clay. 1 9
Parting of black and brown clay 0 1
Rather hard, whitish, laminated marl 1 2
\ Dark-grey, sandy and earthy clay 0 9
Buff- coloured, laminated, marly limestone 2 G
Black laminated clay, including a layer of grey limestone
from 1 to 1 6
Yellow ferruginous stone 1 0
Soft, yellowish, sandy marl, OYerlying an undulating bed of
grey marly limestone, beneath which is disturbed tough
grey marl 5 0
Laminated brown and grey clay, with patches of black clay :
rests on the uneven surface of the bed next below 0 4
Hard, whitish, chalky limestone with Cyprids, and a layer of
chert j stone with small lenticules of dint at the top 1 3
Soft, grey acd white, laminated marl 0 0
Hard flaggy limestone with black flints at the top, pausing
down into chalky and shelly limestone 2 3
Chalky limestone, with Portland fossils 14 0
£
1
CO
c
a
£
a
u
*
Q. J. G. S. No. 197. b
Digitized by Google
50 MESSRS. W. B, ANDREWS A2SD A. J. JTJ KE8-BROWNE [Feb. 1 894,
Fig. 1 shows the curious arrangement of the beds which overlie
the thin layer of grey, brown, and black clay near the base of the
Purbeck series.
Fig. L — Beds setn in Wockley Quarry.
a. Laminated Clay. c. Hard Fissile Marl. e. Yellowish Sandy Marl.
b. Grey Marl. d. Marly Limestone. /. Yellow Ferruginous Stone.
"West of the spot where this sketch was taken, the yellow sandy
marl descends and cuts out the grey limestone and marls, but con-
tains patches of grey marl and pebbles of the grey limestone : while
at the eastern end of the quarry the yellow sandy marl is absent, its
place being taken by a loose grey marl resting on an irregular sur-
face of hard, light-grey, flaggy limestone, the top of the marl being
hard and passing in places into a grey limestone ; these beds are
between 6 and 7 feet thick.
It is evident that much contemporaneous erosion took place
during the formation of this part of tho series, and the details of it
vary in every ten yards. It appears to correspond with the 4 Broken
Beds 'of the Dorset Purbecks. The grey beds seem to have been
deposited first, and to have been subsequently exposed to the action
of a strong current which disturbed them and in places completely
destroyed them, embedding the broken remnants of them in the
yellow sandy marl which was deposited as the strength of the current
diminished. The surface being thus levelled up again, an even floor
was formed, upon which the material of the yellow ferruginous stone
was quietly accumulated.
On comparing the Wockley section with that of Chilmark Quarrv,
it will be seen that neither the thick oolitic freestone of the Chil-
mark Portlandian nor the tufaceous Lower Purbeck limestones
are present at Wockley. There is certainly nothing which can
possibly represent the freestone, and the Lower Purbeck of Wockley
is so different from that of Chilmark that no one particular bed
can be recognized at both localities. If, however, the grey clay
(with limestone-pebbles) of the Chilmark section be on the same
horizon as the confused grey marls of Wockley, there would seem
to be a thickness of about 30 feet at the former locality, which is
represented by only about 2 feet at the latter.
Digitized by Google
Vol. 50.] OX THE PURBECK BEDS OF THE VALE OP WARDOFR.
51
Under such circumstances it might he expected that the plane of
division between the Portland and Purbeck series would be clearly
marked, if not accompanied by signs of erosion ; but this is not the
case, and it is on the contrary difficult to decide where the divisional
plane should be taken. The flaggy aud shelly portions of the 2 ft.
3 in. bed are firmly welded together, and would yield a slab like
that at the Museum of Practical Geology, in which Portland shells
are visible in the lower and Cyprids in the upper part, but these
Cyprids are not freshwater species, being in fact Candona ansata and
C. bononiensti (which are estuarine forms). From the flaggy portion
two species of fish have been obtained {Ophiopsis brevicej* and
0. penicillatus) and also a large species of Archwonhcu* ; but none
of these fossils a fiord very good evidence for classing the flaggy
bed as Purbeck ; even the Arcfotoniscus doubtless existed on the
land-surfaces of Portland times, and might thorefore bo washed into
the shallowing bay or estuary.
The overlying marl contains Cyprids, but they are not recogniz-
able; from the chalky limestone we obtained better specimens,
which Prof. T. Kupert Jones identified as Candona ansata, and a form
like Cypridea punctata, while in its highest cherty layer occurs
what appears to be Cypris purbeckemU associated with a Cardium
and Corbula alata.
Thus both strata and included fossils show a gradual passage
from Portland to Purbeck conditions ; but, as the line must ho
drawn somewhere, we prefer to take it at the base of the laminated
marl, and consequently to relegate the flaggy stone to the Portland
series.
To account for the great difference between the Wockloy and the
Chilmark sections, we can only suppose that Wockley lay in tho
track of a tidal current which prevented rapid deposition and subse-
quently caused the erosion of the grey beds ; while the Chilmark
area was either a low-lying sandbank or a backwater out of the
track of the main current, aud close to the influx of springs or
streams which contained a large amount of carbonate of lime in
solution, the carbonate of lime being deposited partly as oolite
while the lagoon was still opeu to tho sea, and partly as tufa after
this opening had been closed.
If the white marl be taken as tho basement-bed, the thickness of
Lower Purbeck exposed at Wockley is about 22 feet (see p. 4!J).
The Cyprids observed in the oolitic stone at the top of the quarry
proved to be Cypris purbeclensi*.
Near the hamlet of Kidge, 1J mile north of Wockley, and about
1 mile west of the Chilmark section, is a quarry exposing beds
which we believe to be in the higher part of the Lower Purbeck
series, tho floor of the quarry probably lying not far above the
horizon of the topmost bed in the Wockley section. The succession
observed at llidge in 1890 was as follows:—
e2
Digitized by Google
52 MESSRS. W. R. ANDREWS AND A. J. JUKB8-BR0WNB [Feb. 1 894,
FeeL Inches.
Bark brown soil 1 0
12. Weathered marlstone or ' lias ' 1 0
11. Buff-coloured marl, with two seams of grey clay 0 6
10. Soft, fine-grained, marly oolite, with thin layers of harder
com pact marlstone in the lower part 2 3
9. Soft, yellowish, calcareous oolitic sand 0 9
8. Very hard limestone, consisting of shelly layers alternating
with seams of compact marlstone 0 10
7. Soft marl in thin layers 0 8
6. Soft, yellowish, oolitic stone, with thin layers of marl 2 6
6. Hard grey limestone, full of shells 2 4
4. Firm oolitic stone, almost a pisolite in places, with inter-
laminated layers of marl in the lower part and a 2-inch
layer of brown marly clay at the base 3 3
3. Soft calcareous stone, passing down into hard limestone with
vertical joints, and lying in thick courses 3 3
2. Soft, grey, laminated, argillaceous marl 1 0
1. Firm buff-coloured marlstone, breaking with semiconchoidal
fracture ; base not seen 3 0
22 4
Limestone No. 3 is of estuarine origin, for the central pnrt is
full of marine shells, Corbula ahtta^ with small species of Ptma,
Cardiuniy and Leda, Serpula, and small Univalves. There are also
many angular hollows left by the solution of salt-crystals ; the walls
are so crushed in, that some of them look like four-rayed
stars ; some are empty, others are filled with a yellowish
ferruginous earth.
Nos. 6 and 9 are curious oolitic sandstones ; when treated with
dilute hydrochloric acid the mass of the rock disappears, but if the
residue is washed and evaporated a very small quantity of fine sand
remains, consisting of minute grains of clear translucent quartz.
Such granules probably form the nuclei of some of the oolitic
grains, but most of these must be purely calcareous.
The higher bed No. 10 is only partially oolitic, and appears to be
a mixture of oolitic particles with triturated shells of Cyclas, Cyprids,
etc. ; but no specifically recognizable Cyprids were observed.
The dip of the beds at this quarry is about 4° north, probably
lessening southward, in which direction the ground rises ; and on
the top of Lady Down there are quarries in nearly horizontal
Middle Purbeck beds. At a lower level again, on the southern
side of the common, by the lane leading to Chicksgrove, layers of
marlstone and oolite like those at Ridge can be seen ; and the base-
ment-beds of the Lower Purbeck, with the hard chalky limestone
below, cross the lane at its lower end.
Similar oolitic beds are also exposed in the bank at the western
end of the lano leading from Chilmark quarries to Teffout, and
here they contain the characteristic Lower Purbeck form Cypris
purbfekensis.
Beds of the same kind were also proved in 1890 below the
Middle Purbeck, at the bottom of the large quarry at Tcffont Evias.
/ Digitized by Google
Vol. 50 ] ON TOE PCRBBCK BEDS OF THE VALE OF WARDOUR,
53
IV. The Middle Purbeck Gboup.
One of the beet iections in the lower part of the Middle Purbeok
frroup is that to be seen in tho quarry west of Teffont Evias church,
and in 1890 we had an excavation made below the floor of the
quarry for a depth of about 7 feet, in order to prove the nature of
the underlying strata. The complete succession then seen was as
follows, the names given to the beds by the workmen being printed
in small capitals : —
Feet. Inches
( Soil.
Rubble of white limestone 1 0
Marly shale, with a layer of ' beef and lenticular sound of
chert, crowded with silicifled shells of Cyclas 1 0
Bough, greyUh. sandy limestone (Cixdeb-bed), with Onfrca
distorta, Triyonia gihbota, and a spine of Cidaris par-
beekmsi* 1 ft
Yellowish, calcareous, sandy shale 0 9
Hard, grey, shelly limestone iu three courses, with slialy
partings ; Chelonian bones, Hybod as- spines, E*thcria
eubquadrata, Cypridra punctata, Lyprwne Bnstovii,
Cyprtimt up., and Metticypris sp 2 9
Dry, buff-coloured, sandy and calcareous shales (Scale)
full of small Modu>l<B ; Pycnodont teeth 1 6
Buff-coloured, marly clay 0 8
Hard, compact, grey marlstone (White Lias), jointed
Tertically, no fossils found 2 0
Dark grey or black *hale, with M&sodon mucntptents,
Ettheria Andrcwtii, Cypridea ftutciculata, and C. punctata 0 2
Hard, grey, shelly limestone, showing ripplo-marks and
sun-cracks, splitting into slabs which are used as flag*
stones ; Cypridca fatciculata, CycUu, fish-vertebne and
scales (TiLasTosB or Flagstojmb) 1 6
Yellowish laminated shale, with layers of crushed shells ... 0 7
Brown and black, shaly clay, contains Cypris purbeckensis
plentifully, C. fatciculata (less common), EstAeria An-
drewsii?, Cyclas, and scales of Lepidofus 1 0
Very hard, compact, grey marlstone (Lias No. 2); fleh-
remains : Leptoleph, LoccolepU, and Plcurupholis, with
ArckaoHUcua and wing-cases of Coleoptera 3 6
Brown clay 0 G
80ft, yellowish, marly sand 1 6
Hard grey marlstone, rery heavy (Lias No. 3), with Cypris
purbcekensU, PUurypholit, insect-remains (Coleoptera
and LibeUuin), and plants (Pafaocypari*) 3 tl
Brown clay (generally the floor of the quarrjr) 0 4
Yellowish sandy marl, with oolitic groins and a thin layer
of compact marlstone near the top, contains Cyprids
(? purbeckewis) and Crocodile- scales 2 6
Grey marly limestone 0 6
Soft yellowish marl 0 8
Grey marlstone (or Lias), with vertical jointing 1 3
Soft sandy marl 0 6
Hard grry and brown marlstone, compact and heavy, with
oehreous patches and markings seen for 2 0
In accordance with the classification of the Purbeck series by means
of the various species of Cyprida, as proposed by Edward Forbes and
confirmed by Prof. T. Rupert Jones, we have token the line of division
Digitized by Google
54 MESSES. W. R, ANDBEWS AND A. J. JT7KES-BB0WNE [Feb. 1 894,
between the Lower and Middle groups at the point where Cyjtridra
fasciculate first makes its appearance. This is in the brown and black
clay, which is a conspicuous bed in the section, and consequently a
convenient plane of division. It is true that Cypris jmrbecJceruis is
ntill the most abundant form, so that the bed might be grouped
with either division, but we prefer to regard the iucoming of
C. fascictdata as marking tho base of the Middle Purbeck lieds.
A quarry south-west of Lower Chicksgrove, on the southern side
.of the railway, exposes the same part of tho series as that seen at
Teffont, and there is a very close correspondence between the two
sections, in spite of their being 1£ mile apart. The brown and
black shaly clay (taken as the base of the Middle Purbeck group) is
seen resting on the same marly limestone- as at Teffont, but the
overlying yellowish shelly shale has thinned out, while the 4 Flag-
stoue ' has thickened to 3 feet, and forms two courses of hard
shelly fissile stone. This bed contains Cyrena media, Paludina cari-
nifera?, Cy-priden fasciculata, Estheria gubquadrata, with branches
of Thvyites and impressions of long reed-like leaves.
Above the 4 Flagstone ' comes a thin shale, and then the ' White
Lias,' with just the same thickness as at Teffont, namely 2 feet.
The overlying beds, including tho * Scale ' with Mwliohr, are similar ;
but the succeeding grey shelly limestone is only 1 foot 9 inches
thick. It is here a very pure limestone, mado up almost entirely of
Cyprid and Cyclas-shcfts, Cypridta fasciculata and C. punctata being
abundant.
The * Cinder-bed * is of much the same thickness as a t Teffont,
but lies in two courses : a lower course of hard grey marly limestone
without Ostrea>, but containing a few individuals of Cyrena (? media),
and an upper course, partly hard and partly loose and rubbly, with
many fossils, among which Ostrea distorta, I'riyonia yihbosa, and
Cyrena media are conspicuous.
Above the 4 Cinder-bed ' come the following iu ascending order : —
Inches.
1 . Soft, brown, marly clay and yellowish shaly marl 8
2. Soft grey clay, with a lenticular layer of whitish limestone and
a thin layer of • beef ' 9
8. Hard, marly, oolitic limestone with Cyclas and Cyrena 10
A quarry on Lady Down, about 1 mile north-west of this, carried
a similar section to a somewhat higher horizon, tho part above the
4 Cinder-bed ' being as follows (in descending order) : —
Feet. Inches.
Dark-brown sandy soil 2 0
Traces of limestone, with ArchaonUctts 0 2
Yellowish, calcareous, gritty sand, with layer of reddish-brown
nandstone at the base 0 6
Whitish fissile limestone, in thin layers 0 4
Hard shelly limestone, in one massive course 1 3
Compact white limestone, passing down into flaggy oolitic and
shelly limestone 1 6
Laminated marly bed«. yellowish and brownish, with layers of
' beef * and whitish shell-marl 1 4
ClNDEK-BED below.
Digitized by Google
Vol. 50.] OS THE PURBECE BEDS OF THE TALE OP W ARDOUR.
53
The section exposed in the railway-cutting, £ mile south of Tcf-
font and on the southern side of the river, carries the series still
higher, and shows also that a certain lateral change takes place in
the higher beds as they are followed from west to east. This section
is now partially obscured by talus and turf, but was measured by
one of us in 1880, when the beds were all clearly exposed along its
whole length ; and even now, by combining exposures on the northern
and southern sides of the cutting, the following descending suc-
cession can be made out : —
Feet. Inches.
Wet grey and yellow sand 3 or 4 O
Lighr-grey sticky clay 1 8
Soft marly clay*, with thin, brown, iron-stained layers 2 0
Light buff-coloured marl 0 4
Hard, whitish, grey-hearted silty limestone, weathering into
angular blocks with Tertical fracture 1 0
Soft, laminated, grey and brown, sandy marls and clays, with some
shelly layers and a seam of ' beef 2 0
Rather hard, brown and grey, sandy stone 0 G
Brownish sandy clay, with thin irregular and lenticular seams of
sandy limestone 1 0
Hani, buff-coloured, sandy limestone, laminated at top and bottom ;
contains large Ct/r&ue 1 0
Soft sbaly marl, with crushed shells 0 0
Layer of 'beef 0 1
Laminated shelly marls, brown, yellow, and whitish, very hard
in parts, full of bivalve shells 0 10
Hard, grev, marly limestone (Arch&anucug-bed), containing also
Chirm dintorta, CorbuUe, and a Cardium 0 6
Grey sandy limestone 0 2
Dark-brown ferruginous sandstone 0 3
Soft sandy limestone ... 0 2
White fissile limestone, splitting into layers from 1 to 2 inchea
thick ! 1 4
Hard shelly Limestone, here very thin 0 1
Soft whitish limestone 0 8
Layer of 'beef ' 0 2
Soft, laminated, shelly limestone, full of crushed shells 0 (i
Chalcedonic chert full of Cyclat from 1 inch to 0 3
Brown clay 0 2
Cixdbr-bbd, rery hard in places, loose and soft in others ; Ostrea
dittorta, Trigonia gibhota, and Tr. densinoda 2 6
Hard blue-hearted limestone in two or three courses, with marly
partings, Ottrea and Univalves 3 0
Yellowish sandy limestone 1 0
Dark clay 0 2
Hard grey marlstone, Fibst Lias 1 6
Grey clay 0 2
Hard, grey, shelly limestone (the Flagstowb) 2 0
29 6
The above section was described by one of us in 1881, and was
accompanied by a diagrammatic view of tho vertical succession ; but
it should be mentioned that this was a generalized view, every bed
seen in the cutting being inserted, and was not a vertical section
taken at any one point. Thus the shelly limestone underlying the
fissile limestone, which was only 1 inch thick where our section was
Digitized by Google
56 THE PCKBECK BEDS OP THE TALE OP WARDOUR. [Feb. 1 894.
taken in 1890, is shown in the diagram of 1881 as 12 inches
thick ; in reality it thickens from 1 to 12 inches westward in a
distance of 30 yards, and it is this bed in its expanded form which
is touched at the top of the quarry at Lower Chicksgrove, and which
is seen to be nearly 3 feet thick in the quarry on Lady Down (p. 54).
On the other hand, the overlying white fissile limestone thickens
from west to east, being only 4 inches thick on Lady Down and at least
16 inches in the railway-cutting. The lower white limestoue seems to
be a local bed which thins out in both directions. The diagram
(fig. 2, on the opposite page) shows the variations in the strata
between the two well-marked horizons of the 4 Cinder-bed* and the
Archtronisctis-Wmis&tone at the two localities mentioned, and at a
third one still farther east.
We now come to the most easterly exposures near Dinton Station,
where the eastward dip brings in still higher beds and ultimately
those which we believe to be of Upper Purbeck age. The cutting
which runs through a wood, and commences about 700 yards west
of Dinton Station, has been quarried back for stone and exposes the
same part of the series as that seen in the middle of the larger
cutting to the west, but several of the beds have thinned out, so
that the space between the * Cinder-bed ' and the topmost sands is
greatly contracted. The lower part of this section from the Archceo-
wwctM-bed downward is given in fig. 2 ; above that horizon the
following beds are seen in the eastern corner of the old quarry : —
Feet. Indies,
Sticky grey clay, seen for 0 6
Brownish clay, passing down into whitish marly clay with irregular
lumps of hard shelly limestone at intervals 1 0
Layer of fibrous carbonate of lime (' beef) up to 0 2
Layers of grey ahaly clay, sandy shale, and yellow sand, with
crushed shells 2 6
Lenticules of sandy limestone and 'beef' in brownish sandy
shale 0 6
Hard, buff-coloured, sandy limestone, solid in the upper part,
laminated in the lower part 1 0
Brown sandy shale and clay, with crushed shells 0 8
Hard, crystalline, shelly limestone 0 1£
Compact, grey, marly limestone (Arci*oni*c*sbed) with many
specimens of Archaonucu* 0 4
6 9|
These beds dip south-eastward and appear to pass below a thick
bed of clay which is now grassed over, but seems to be about 8 feet
thick ; this is overlain by soft yellow sand with a thin surface-
covering of gravel, the two together often slipping over the clay.
The cutting then ends, and the ground falls to a little watercourse,
which passes under the railway about 400 yards west of tho
station.
We take this clay and sand to be the basement-beds of the Upper
Purbeck group, but we are by no means sure that they are in direct
succession to the beds above described. If the section just given be
Digitized by Google
3
f
)igitized by Google
58 MESSRS. W. R. ANDREWS AND A. J. JTJKE8-BR0WXP. [Feb. 1 894,
compared with that of the cutting south of Teffbnt (p. 55), it will be
seen that the succession is similar for about 6 feet above the Archo>-
onticut-bed : the variations are only such as might well occur in
the space of a mile, and are probably in part due to the individual
layers being differently grouped by ourselves. South of TefFont
cutting, however, there is a whitish limestone succeeded by about
4 feet of marly clay, followed by yellow sand ; at first sight we took
the clay and sand to be the same as thoso of the Dinton cutting,
and inferred that the whitish limestone had thinned out eastward,
but subsequently we saw reason to doubt this correlation on the
following grounds.
In the wood south-east of the quarried cutting near Dinton there
are old stone- workings now overgrown, but at the bottom of this
wood the Archa>oniscti*-be<i and the overlying sandy laminated lime-
stone crop out in the river-bank near the sluice-hatches. They
are doubtless carried down to this low level by the south-easterly
dip ; but, in order to see what beds could have been quarried here
above the Arcfueonuteus-limestone^ we had a trench cut down the bank
of the old quarry on the north-eastern edge of the wood, and in this
were exposed the following beds : —
Feet. Inches.
Yellow and grey sand, with lump* of brownish calcareous sand-
stone containing Cyrena and Melanopsis; thin layers of grey
clay occur in the lower part, which passes down into the next... 2 0
Stiff grey clay, with thin layers of grey sand and thicker layers of
yellow sand 1 0
Stiff grey clay, yellowish near the base ... 2 0
Hard, whitish, silty limestone, breaking vertically into sharp
splintery fragments 0 5
Soft, buff-coloured, shaly marl with Cypr idea punctata 0 7
Hard, buff-coloured, grey-hearted, &andy limeatone 0 7
Flaggy and shelly stone, with layers of * beef 0 4
Grey marly clay, with layers of whitish shell-marl 1 0
Sandy and shelly limestone with Cyrena 0 4
Floor of hard stone.
8 3
These beds are quite different from any exposed in the railway-
cuttings near by ; but the hard, whitish, splintery limestone is not
unlike the whitish limestone which occurs about 8 feet from the top
of the deep cutting south of Teffont (p. 55). We are strongly inclined
to think that the beds visible in the trench are the equivalents of those
seen at the top of the above-mentioned cutting, and that they lie below
the thick blue clay and yellow sand of the Dinton cutting, being
there cut out by a fault, which crosses the railway-line where the
stone beds end abruptly. If this be so, the thickness of the strata
between the Archtr.oniscit*-\\mesbone and the thick blue clay is some
8 or 10 feet greater than it appears to be in the Dinton cutting,
and these beds must be added to the Middle Furbeck group.
Digitized by Google
Vol. 50.] OX THE PURBECK BEDS OF THE VALE OF WARDOtTB, 59
V. The Upper Fubbeck Group.
As stated on p. 50, we take the thick bed of clay seen in the
quarry -cutting west of Diuton to be the base of the Upper Purbo.k
group. We do so, more for the sake of convenience than for any
resemblance to beds elsewhere ; but the soft and purely siliceous sand
which overlies the clay is a conspicuous bed, capiible of identification
if exposed at other localities. A slip in the southern bank of this
cutting in October 18i)0 showed the following section : —
Feet. Inches
Oravel 3 to 4 0
Yellow sand, with seams of grey sandy clay from 4 nich to 4
inches thick 1
Yellow and brown sand, in alternating layers (base not seen) 8 0
Wet grey sand, passing down into silty clay
Stiff grey clay at the base.
"We may, therefore, assume that there is at least 10 feet of the
sand in this cutting.
East of the watercourse and cattle-creep there is another cutting
almost entirely grassed over, but its western end does not seem to
be in sand, as it would be if the south-easterly dip were continued ;
and moreover the first beds seen are dipping westward, so that we
suspect there is a line of fault between the two cuttings.
A hard shelly limestone crops out in the bank at intervals, rising
eastward ; and at a point about 80 yards east of the watercourse
we made a narrow trench down the bank, finding the following
beds in the lower two-thirds of the slope : —
Feet Inches.
• Beef (fibrous carbonate of lime) 3
Brown sandy clay 4
Soft, calcareous, shelly marl G
Stiff blue clay U
Sandy clay, with layers of 4 beef * 4
Grey shaly clay 3
Soft yellow marl, with crushed shells 8
• Beef ' (1 inch) and brown sandy clay 4
Hard shelly limestone, grey inside, weathering yellowish ; with
Unto 6
Buff-eoloured or brownish nodular limestone, with Cyrrna media
and Paludina 3
• Beef ' and sandy stone 4
Yellow and grey sand, with a log of endogenous wood in plaoe... 3 0
7 6
The soft sand at the bottom we consider to be the same as that
seen at the top of the western cutting, and as the overlying beds
contain Cyrena, Paludina, and Unio, we are inclined to regard them
as the equivalents of the {/wto-beds of the Dorset series. If our
reading of these partially obscured sections be correct, the eastern
cutting traverses an anticlinal flexure, the western limb of which is
faulted against the beds seen in the other cutting. We assume, in
fact, that the strata are broken by two faults, each with a down-
throw to the east as shown in the section on the next page ^Gg. 3).
Digitized by Google
60
MESSRS. W. R. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 89 4,
4
3
CO
1
1
1 1
c IS
E
9
I
!
a
!
at B
From the place where the
above succession was measured
the shelly limestone can be
traced in the bank, at first
rising and then falling east-
ward to the level of the rails.
The other beds doubtless come
in above, and where the bank
is cut back for the railway-
siding a different set of beds is
exposed, dipping at an angle
of lo° to N. 30^ E. The section
is : —
t->
u
c
-
(IS. Loam and gravel...
12. Light-grey marly
and silty shale ...
11. Grey clays, with
thin layers of yel-
low sand
10. Grey marly clay ...
9. Hani, dark - grey,
calcareous grit...
8. Sandy marl
7. Yellowish marly
limestone, break-
ing vertically ...
6. Yellow marly clay,
passing down into
dark-grey shale .
6. Hard, dark -grey,
calcareous grit...
4. Light bluish-grey
clay
3. Grey and brown
sandy marl, with
stony nodules
near t he top
2. Grey sandy marl,
with thin layer
of 'beef
1. Yellowish - white
shelly marl
Ft. In.
4 0
4
0
2
1
0
0
2
2
6
3
6
3
9
14 9
With the exception of the
lowest stratum of shell v marl,
these beds are quite different
from any seen elsewhere in the
Vale of Wardour. We fouud
Cyprids in the beds numbered
ft, 6, 7, and they were identified
by Prof. T. Rupert Jones as
Cypridea punctata, with the
addition of Cyprions Bristovii
Digitized by Google
Vol. 50.] 05 THE PURBECK BEDS OF THE VALE OF WARDOT/R. 61
in the dark shale. Nothing like Cypridea fasciculate, occurred in
any of the beds.
The dip being steep, it is not surprising to find that a great
thickness of Upper Purbeck clays comes in to the eastward within a
very short distance. Three hundred yards north-east of the above
section are some cottages, where a well was sunk in 1 884. From
the account of the well-sinker, and from examination of the material
thrown out, this well seems to have proved the following beds :—
Feet.
Yellow clay 3 or 4
Light-grey eilty marl 11 or 12
Stiff grey clay 6 or 6
Very stiff, grey and brown clays about 20
Hard gritty stone at the bottom ; this being
punched through, water rose at once a few inches
about 40 feet
In the material thrown out and coming from the stiff grey clays,
one of us found Paludina carinifera, an Unio, some fish-scales, and
many Cyprids, the last- mentioned being identified by Prof. T. Rupert
Jones as Cypridea punctata and a smooth variety like G. vahlcims,
Cypriont Bristovii, and Darwinula JegumituUa. A specimen of the
bottom stone-bed was also obtained, and proved to be exactly like
the layers of hard calcareous grit seen in the railway-siding ; it also
contained C. punctata^ and we have little doubt that it is the upper
of the two calcareous grits.
How much farther the Upper Purbeck Beds extend eastward and
north-eastward we were unable to ascertain. Thore are only low-
lying fields in that direction, the ground is obscured by a gravelly
soil, and the railway passes on to the alluvium. Wo think, however,
that the yellow Wealden Clays come in a very few yards north of
the well.
On the southern side of the river, in a field near Catherine Ford,
which is due south of Dinton Station, a shallow well has recently
been dug (1892) and exposed beds like those seen in the railway-
siding, namely : —
Feet Inches.
Loam and grarel 3 0
Marl 2 0
Dark-grey grit 0 2
Grey marly clay 1 0
Dark-grey grit 0 3
Red sandy marl 3 0
Hard grey marl 1 3
10 8
There are three other localities where some of the beds which we
have classed as Upper Purbeck seem to be present, but unfor-
tunately no clear sections are exposed. One is ou the high ground
south of the railway-cutting and north-east of Daslott Farm.
Another is on the rising ground south of the quarry in the Middle
Digitized by Google
62 MESSRS. W. R. ANDREWS AND A. J. JUKES-BROWNR [Feb. 1 894,
Purbeck at Lower Chicksgrove ; the highest ground here consists of
grey shaly clay which is exposed by the roadside, and may be the
thick clay which we take as the base of the Upper Purbeck ; the
ground then dips into a hollow where higher beds may occur,
but, as the general dip here seems north-easterly, this is doubtful.
This very north-easterly dip, however, makes it possible that Upper
Purbeck Beds come on in that direction, and the anomalous beds seen
in an old quarry and in the railway-cutting by Chicksgrove Farm
may possibly belong to the Upper, and not to the Middle group.
The third locality, where beds higher than those wo have grouped
are present, is north of Ley Farm and south-west of Teflont Evias.
Here the soil is very sandy, and pieces of endogenous wood (Endo-
genites) frequently occur in it. We have little doubt that there is
here an outlier of the thick sand seen in the cuttings near Dinton,
and immediately north of Ley Farm there is a spring — which is
suggestive of a substratum of clay.
In the first instance, and before we found sand containing
Endoyenites overlain by beds of distinctly Purbeck character at
Dinton, we took these and other outlying patches of sand to bo
remnants of the Hastings Sands. Now, however, wre do not believe
that there is any representative of the Hastings Sands in the Vale of
Wardour : the other sandy outliers resting on Lower Purbeck be-
long probably to the Vectian Sand, which overlaps the narrow strip
of Wealden Clay.
Those who are acquainted with the literature of the Purbeck
Beds and their contents will doubtless observe that, in the preceding
stratigraphical account, no mention has been made of the * Insect-
bed ' discovered and described by the Rev. P. B. Brodie, F.G.S.
This omission is not due to any neglect on our part, for we have
lost no opportunity of searching for traces of such a bed, and have
sought Mr. Brodie's assistance in ascertaining the exact position of
the old quarry where the Insect-limestoue occurred.
Mr. Brodie found the place so altered, when he visited tho spot
with Mr. Andrews in 1888 after the lapse of more than 40 years, that
he was unable to recognize the exact site of the quarry, but it was
" at the bottom of the field opposite the railway-station, not far from
the road, and near the river." There is a pond in the position thus
indicated : it is possible that this is on the site of the quarry, aud
that the Archtfoniscus-bcd is hero brought up by the anticlinal seen
in the railway-cutting. Mr. Brodie informs us that the limestone
of the 4 Insect-bed ' was stacked in some quantity at the time of
his first visit (in 1840), and it had without doubt been quarried from
below the level of the water which then occupied the bottom of the
quarry : the Archironisciis-bcd, or, as he calls it, tho * Isopod-lime-
stone,' being visible above the water-level.
In a later paper 1 Mr. Brodie gave a section taken by the Rev. O.
Fisher in a quarry on the south side of the river Nadder, near
Teffont Mill, where a laminated limestone does occur in the position
1 Quart. Jouru. Geol. Soc. vol. x. (1854) p. 476.
Digitized by Google
VoL 50.] ON TILE PURUBCK BEDS OF THE VALE OF WARDOUR. 63
assigned to the Insect-bed, but it does not appear that any insects
were found in it at that locality.
When Mr. Brodie first visited the Vale of Wardour few exposures
of the strata were to be seen, and he had no idea that the whole
Purbeck series was there represented. In his later paper he states
that when he collected from these beds he regarded " the Insect-
and Isopod-limestoncs as belonging to the lower part of tho Jjower
Purbecks." It was in this way that he came to consider the
highest bed of *lias' in the Middle Purbeck at Teffont as the
equivalent of tho Isopod- and Insect-limestones, though he notes
the lithological difference of the rock and the fact that it only
contains a few insects.1
It would appear, therefore, that the bed from which Mr. Brodie
obtained the greater number of his insect -remains occurs in the
upper part of the Middle Purbeck, just beneath the Isopod or
Archm)nvtcit8-bod ; but as we have failed to find any inscctiferous
limestone at this horizon in the numerous sections which are now
open, we are compelled to conclude that it is a stratum of load
occurrence, confined to a very small area in the most easterly part
of the Vale of Wardour, a view in which Mr. Brodie now concurs.
VI. General Conclusions, and Comparison of Dorset
and Wiltshire Purbecks.
From the sections given in the preceding pages it will be seen
that we have now better data than previously existed for calculating
the thickness of the several parts of the Purbeck series in the Vale
of W ardour. There is still some difficulty in fitting in all tho ex-
posed sections with one another, and we have not found the actual
summit of the formation ; but wo think that there are not many of
its component beds which we have not seen, and that our estimate
of the total thickness will be found a near approximation to the
truth.
Lower Purbeck. — If we take the "Wockley section, which is re-
peated at Chicksgrove, as giving the more prevalent type of the
basement-beds, we have there from 22 to 24 feet of Lower Purbeck,
and in the Ridge quarry there are over 21 feet (see pp. 49, 52). It is
clear that these two sections do not overlap, and how much comes in
between them we cannot say ; but in the lane from Chicksgrove to
Lady Down there is quite room for GO or 70 feet between the base-
ment-bed and the outcrop of the oolitic beds. Finally, nearly 17 feet
of strata occur in the Teffont quarry which seem to be above any
exposed at Ridge ; consequently we have actually seen over 60 feet
of Lower Purbeck beds, and, allowing for the gap between the
Ridge and Wockley sections, wo consider that 70 feet is a fair
estimate of their average thickness. The diagram on p. 65 (fig. 4)
shows the vertical succession which is assumed iu this estimate : —
1 See « Fossil Insect*/ pp. 18, 19.
Digitized by Google
Fig. 4. — Diagram showing the
Vertical Succession op the
Pcrbecx Beds.
Vertical Scale: 12 feet=l inch.
DinloH Well.
I
00
§
o
F'ir*t Cutting.
Din ton
Second (fitting.
Cut tint} S. of
TrjJ'oiit.
Band
Litnoaton*-.
CO
§
D
P-
s
0
C
Chirk'ijmrt
Quarry.
IlltllUillll
'il. 1 ' it"
l :;T:
YA\om
Clay.
Grry
silty
Marls.
Grey
and
Brown
Clays.
Calc. Grit.
• Beet:
Clay and Marl.
Limestoiit-9.
Sand.
Calfl. Grit
Sand.
Clay.
?Gaj>.
Clay and Shalt-a.
Sandy Limeatoni*
Arckaoiti»cu*-bid-
White Limestono.
ClNUER-IIKD.
FLAOSTOJfB.
Brown Clay.
Digitized by Google
U
*
w
e
9
S
e
►3
WoekUy.
Tufont
Quarry.
Quarry.
* Lias.*
Oolite.
Marl*
and
Oolites.
Oolite.
Oolitic Li
Marly Stone.
flandy Marl.
Hard
Mnrls, Clays, and
Limestones.
Y*Uow and grey
Marls.
Laminated Clay.
White Liraefetone.
White MarL
^ White Limestone.
ClXDKR-BEn
Shelly Limeatone.
Scale.
' W'HITR LfAS.'
FUAGSTOSK.
Dsrk Clay.
' Secokd Lia*.'
' Third Lias."
Oolitic Marl.
• Fourth Lias."
[^TVa^ ' FlFrH LlA*'
Q. J. U. S. No. 197.
Digitized by Google
66 MESSRS. W. R. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 894,
Middle Purbeck. — Basing this upon the brown and black clay
seen at Teffont and at Chicksgrove. it will be found that, though the
thicknesses of individual beds in the two sections vary, the vertical
distance from the basal clay to the top of tho Cinder-bed is almost
exactly the same in both, namely, a little over 12 feet. The great
cutting on the line south of Teffont shows 19 feet •of strata al>ove
the Cinder-bed, and if these lie entirely below the clay and sand of
tho Dinton cutting there is that much (and possibly more) to be
classed as Middle Purbeck, for we havo no complete section of this
part of the series. A total thickness of 32 feet is therefore probably
below the mark.
Upper Purbeclc. — The clay and sand in the Dinton cuttings must
be from 18 to 20 feet thick, and between the top of this eand and
the top of the second seam of calcareous grit there is at least a
thickness of 8 feet. This grit forms the floor of the Dinton well,
which is about 40 feet deep. Hence there is at least 66 feet of this
division, and how much more lies beyond we do not know — probably
more than 2 and less than 12 feet ; but, taking the former figure, wo
have a minimum thickness of 68 feet.
Putting the estimated thieknoss of tho three divisions together,
we have —
Upper Purbeck «8 foet
Middle Purbeck 32 „
Lower Purbeck 70 „
170 feet.
Considering tho distance that intervenes between the Vale of
Wardour and the coast of Dorset (about 132 miles), it is really re-
markable that in a set of cstuarinc and freshwater strata there
should be so close a correspondence between the two series that
many of the subdivisions which have been recognized in the Dorset
sections can also be distinguished in Wiltshire. The Wiltshire
Purbeck strata do not in fact differ from the typical facies of
Durleston Hay to any greater extent than those of the Upwey (or
Kidgeway) section do.
The first point of similarity is that within the small area of the
Yale of Wardour the basement-beds show a variation similar to
that which occurs in Dorset, but only at sections some distance apart.
The basement-beds at Chilmark resemble the ' Cap ' of the Isle of
Purbeck, but the basement-beds at Chicksgrove and Wockley re-
semble those at Upwey, where the lowest Purbeck bed is a limestone
about 1 foot thick, separating into three layers, the highest of
which contaius fish-remains (Jfistionotus breviceps), the second a
large Arclutoniscus, and the lowest Cyprids and Ptdadina. This
rests on soft, sandy limestone-with-tlints, so that the succession is
not the same, although similar.
The next noticeable resemblance is tho occurrence of broken-up
limestone and contorted marls, which seem to occupy the place of
tho k Broken Beds ' of Dorset. These are also succeeded by a set
of beds in which Cypri* jmrbeckmsis is abundant, and are therefore
comparable with the ' Ci/yjrif-frcestones ' of Dorset. The Hidge
beds, with their abundance of Cardium, Corbula, Leda, and Serpula,
Digitized by Google
Vol. 50.] ON THE PURBECK BEDS OP THE VALE OP WARDOUR. 67
are evidently the equivalents of the 4 Cockie-beds ' and especially
resemble those of the Upwey (Ridgeway) section, where there is
much more limestone than marl and where one of the limestones
is described as * oolitic-looking.' The Upwey 4 Cockle-beds ' also
contain small forms of Cardium, Corbula, I^da, and Serj>ula, which
are probably the same species as those found at liidge. There was
evidently a widespread irruption of the sea at this particular epoch,
converting the freshwater lakes of the C'^m-freestonea into
saltwater lagoons.
The highest beds of the Lower Purbeck, with their Cyjrris puc-
b€ckensisy insect- and fish- remains, show that freshwater conditions
were once more predominant, the marls, marlstones, and oolites of
the Vale of Wardour being clearly the equivalents of the 4 Marly
Freshwater Beds ' of Dorset.
At the base of the Middle Purbeck group there is a set of beds
(between 10 and 11 feet thick) which are not unlike those of the
Cherty Freshwater group at Durleston Bay, except that they do
not contain chert. They have a similar black and brown clay at
the base, and they contain a flaggy shell-limestone of the same
character as the lowost beds worked in the Durleston quarries. At
Upwey this group is only from 5 to 0 feet thick, and does not
contain limestone.
The 'Cinder-bed,' or oyster-limestone, occupies its usual position,
and is often crowded with Triff&niat as well as Ostrttr. The suc-
ceeding beds van' ranch in Dorset, and the same seems to be the
case in the Vale of Wardour, so that no special horizon above the
Cinder-bed is recognizable. We may, however, notice one point of
resemblance between the Upwey and Wiltshire sectious, and that
is the prevalence of sand and sandy stone in the group which seems
to be the equivalent of the 4 Corbala-beds,' but which in Wiltshire
would bo more suitably termed the 4 Carina-beds.'
As regards the Upper Purbeck group, there is no really clear section
of it, so that we cannot be quite sure thut all its component beds
have come under our notice. Wo are, however, fairly certain
that there are no hard limestones like those of the 4 Broken
Shell-limestones' which form the base of the group in Dorset.
These appear to have thinned out northward, so that the repre-
sentatives of the £/i<»'o-bcds come to lie at the baso of the group,
and these only contain very thin limestones. The thick bed of clay
which we take as the basement-bed, and the soft yellow sand with
EndogeniUs which overlies it, seem to be quite peculiar to the Wilt-
shire succession. Tliey appear to indicate an episode of what may be
termed Wenlden conditions, the influx of rapid currents bringing
down mud and sand, and temporarily preventing the formation of
limestones or marls. This is only what might be expected to occur
on the margins of the Purbeck basin.
The highest beds seen in the railway-siding and in the well at
Dinton bear much resemblance to the shales and clays of the ' Upper
Cy^m-marls,' and here again the absence of 7Wtu//x«-liinestones
is worth noting.
Taken as a whole, the Wiltshire series has a greater resem-
blance to the strata seen in the Upwev or Ri.lgeway section than
" f U
Digitized by Google
■
68
MESSES. W. B. AK DREWS AND A. J. JUKES-BROWNE [Feb. 1 894,
to any other of those in Dorset. The total thickness at Upwey
and in the Vale of W ardour is about the same ; there is a similar
absence of thick limestones, and a singular prevalence of sandy
matter in certain parts of the series : resemblances which suggest
that the two localities were about equally distant from the borders
of the Purbeck area of deposition, the one from the western, the
other from the northern border. If the rate of diminution of thick-
ness can be regarded as any guide to the extent of this area, its
western limit must have lain within 10 miles of Upwey on the
west and within ^0 miles of TefFont on the north. It would be verv
interesting to know whether Purbeck Beds exist beneath the Vale
of Pcwsey, for we agree with Prof. J. F. Blake in doubting whether
the so-calied 4 Purbeck ' of Swindon is coeval with the true Purbeck
of Wiltshire aud Dorset.
VII. List op Fossils.
The following list is by no means an exhaustive one ; it includes
such fossils as we were able to obtain from time to time, but we
did not collect or attempt to identify all the small bivalves C?Cyclttg)
which crowd some of the beds, and the 4 Cinder-bed' of Lower
Chicksgrove would probably repay more persevering search than we
were able to bestow upon it. We are indebted to Mr. A. Smith
"Woodward, of the British Museum (Nat. Hist.), for examining and
naming the fishes, and to Messrs. G. Sharman and E. T. Newton for
identifying some of the mollusca.
Reptilia.
Theriosuchus pusillm, Owen . . . .
Pleuroetcrnum (pvtdum ?), Owen.
Pisces.
Aster acanthus verrucosus (spine), Egert.
Hybodm strictus, Ag. (spine)
Shark's teeth, vertebra*, and scales
Coccolepis Andrtum, Traq., MS
Leptolepis lirodiei, Egert
Mcwdon niacropterus^ ?, Ag.
Lepidotus {minor 't), Ag
Oxygimius tenuisy Ag
Ophiopsis breviccps, Egert
„ pcnicillatux, Ag
Macrosemius, up. nov
PUuropholi* lovgicauda, Egert
„ attenuata, Egert
Lower
*
*
#?
#
• ■ ■
Middle
Pt'KBECK.
*
*
*
*
*
*
Upper
1 [Mr. A. Smith Woodward kindly informs us that this species has not
hitherto been recorded from Britain. The type occurs in the Lithographic
Stone of Soleuhofen, and though the Wiltshire specimen is much smaller (pro-
bably dwarfed by local conditions) he cannot otherw ise distinguish it. He uIho
finds a new fish among tbuse sent to him ; this is related to Macro* mim perfo-
rate, Sauvage, from the Portlandian of France.— Jan. 12th, 18U4.J
Digitized by Google
Vol. 50.]
ON THE PTRBECK BEDS OP THE TALE OF WARDOUR.
List op Fossils (continued).
09
Lower
Gasteropoda.
Mclanop*i* Popei, Forbes, MS.
Paimiiua carin\fera, Sow
Valvata
Forbes, MS.
I
Lamellibranchiata.
Cardium morinicum, J)e Lor.
«p
Cyrma media, Sow
„ parva. Sow
Corbula alata, Sow
Modiola, sp
Ostrea dittorta, Sow
Isda, sp
Prma, sp.
Gerrillia or Aden fa, Bp
lYUjonux tjihkosa. Sow
„ c/f ,*si'w <></</, Ef h
tni© (comprcsnus ?), Sow. . . .
Middle
v •
Upper
• . .
• • •
• * ■
• ■ •
• - •
...
*
Crustacea.
Arvhaoniscus Iirodiri, M.-Edw
Candona annata, Jones
„ bowmiemi», Jones
Cyprw purheckensi*, Forbes
Cyjtridea fojtciculata, Forbes
„ punctata, Forbes
Cyrpriont Brigtovii, Jones
iJanrimda Icguminella, Forbes
Ertheria elliptica, Dunk., Tar. subqua
drain , Sow
Estheria Andreteni, Jones
■ • •
*
Insecta.
Libethda, sp. (wing)
Coleoptera (wing-case9)
Echinodermata.
HemicidarU purbtckensi*, Forbes
Plants.
]
*
#
Cycadeoidea microphyUa, Buckl
F^HumtUe»{aathraria)LytUii, Mant. .
Coniferous wood
Palaocyoaris
-like leaves
*
*
*
.*
*
*
*
*
*
*
*
*
•
*
*
*
*
*
70 MES8R8. W. B. ANDREWS AND A. J. JUKES-BROWNE [Feb. 1 894,
Discussion.
The President said that the Society was much indebted to the
Authors, and especially to Mr. Andrews, for details as to these beds
which he alone could furnish. He (the President ) had often received
assistance from Mr. Andrews when he was working at the Portland
Beds of tho Vale of Wardour, but that gentleman could never interest
him in the Purbccks of the locality — a somewhat monotonous series,
with fossils too often flattened to be recognized. The difficulties of
investigation were considerable ; hence the old view that the Wardour
Purbecks did not exceed 70 feet, whereas the Authors considered
that thev had demonstrated a thickness of 170 fpet. In the Vale of
AVardour there were no fine cliff-sections as in Durleston Bay, and
the entire scries had to be constructed by piecing together the
exposures in different quarries.
The Authors had adduced additional patoontological evidence,
which, in his opinion, tended to strengthen the view that tho
Purbeck. taken as a whole, could scarcely be called a freshwater
formation. Inroads of the sea were perpetually replacing the
freshwater fauna b}' estuarino or marine forms, and such species as
Trifjonia gihbom and Canlinm morint'eum seemed to indicate that a
Port.landian fauna was close at hand. Both in the Lower and
Middle Purbeck Beds these marine horizons were well-marked, and
it was extremely interesting to find that the Authors could correlate
them with the developments in Dorset. The most novel feature
was the discovery of Upper Purbeck strata : these sandstones with
Enflofitnites had little in common with the Upper Purbeck of Dorset,
and had usually beon regarded as of Wealden age. Indeed the
Authors admitted that the conditions were Wealden, but the Cyprids,
as determined by Prof. T. Hupcrt Jones, were held to indicate
Purbeck affinities.
Prof. J. F. Blake remarked on the great value of the paper. He
had not been able to accept the idea of the junction with the Port-
land being in tho middle of a block, and was glad to find that the
Authors also declined to accept this line. On general principles he
considered that, unless there was a physical change accompanying a
faunal one, the latter was of secondary importance. Palaeontology
must be the servant and not the master of Geology. He thought
the Purbecks of the Vale of Wardour were really locally uncon-
formable on the Portland*, and had been laid down in a separate
lake or estuary not directly connected with that of Dorset. He
enquired as to the overlying Cretaceous rocks, because on their
conforraability or otherwise would depend the Upper Purbeck or
Wealden character of the highest beds described.
Prof. T. IIupert Jones, in explanation of the conditions of the
Lowest Purbeck 'flaggy limestone ' and its conterminous strata,
thought that the Portlandian sea, in giving way to the shallowing of
the coast, and the local predominance of freshwater lagoons, must
have been rough enough at times to break up the changing floor,
disturb the new deposits, and make a kind of unconformity, accom-
Vol. SO.] OS THE PURBECK BEDS OF THE VALE OP WABDOUB. 71
panied sometimes by the quiet intermixture of marine and fresh-
water forms of life. As the lagoons communicated with one aud
the same sea, it is not surpriaing that nearly similar conditions of
strata and of fossils should be found to exist, in approximately
uniform succession, wherever tho Purbecks are now opened out.
The genus Cypridea occurs throughout the Purbeck series, and
has an ally now living in the Lake of Geneva. That tho leading
species in the Upper Purbeck (Cypridea punctata) is closely allied
to the next following form (C. valdensis, of the Wealdcn Beds)
there is no doubt ; but it is distinct. The finding of End-tgenites erosa
in place in the Wardour Purbeck clears up some doubts about the
relics of that fossil having been found near Hartwell, Bucks.
Mr. H. B. Woodward remarked that in his original section at
I)inton (Quart. Journ. Gool. Soc. vol. xxxvii. 1881, p. 251)
Mr. Andrews had taken the Woalden boundary at a lower level,
and had considered that the Upper Purbeck Beds were absent. He
was inclined, however, to agrco in part with that interpretation of
the section, believing that the coloured clays and sands with Etulo-
genites should be classed as Wealden. Even on this view there was
no evidence to show that Upper Purbeck Beds were unrepresented.
He bad no faith in fixing a plane of demarcation between the
Purbeck and Wealdon Beds by means of ostracoda.
By permission of tho President, he read extracts from a letter of
the Rev. P. B. Brodie, who desired to state that " When I first
visited the Vale of Wardour there were but few available sections,
and, as a young geologist, I naturally followed the lead of so able a
one as Dr. Fitton. All this was more than half a century ago.
Since then Mr. Andrews' fortunate residence in the district, and the
fine section exposed in the railway-cutting near Teffont, has enabled
him and Mr. Jukes- Browne to study far better sections than either
Fitton or myself had seen, and hence their decision is no doubt
correct as to the stratigraphical divisions which they uow propose."
After alluding to the interesting paper by tho President ( 1881) in
connexion with an excursion of the Geologists' Association, Mr. Wood-
ward observed that the pre-Cretaceous folds in the Purbeck and
Portland Beds, to which the Authors had drawn attention, might bo
compared with those affecting the Jurassic rocks in the Weymouth
and Purbeck area, which Mr. Strahan had lately interpreted in
carrying out tho Government geological survey.
The Rev. W. R. Andrews, in reply, said that tho threefold
division of the Purbeck by Forbes, based on the ostracoda, had
been fully borne out by the investigations of Prof. T. Rupert Jones.
The yellow Wealden Clay overlies the Upper Purbeck, but does not
always rest on the same bed. This the speaker explained by pre-
Cretaceous earth-movements. He thanked the Society, on his own
behalf and on that of his colleague, for the manner in which their
paper had been received.
72
MR. K. A. WALFORI) O.X DKTOZOA FliOM
[Feb. 1894,
6. On some Bkyozoa from (Ju Inferior Oolite of Shipton Gorge,
Dorset. Part II.1 By Edwiit A. Walford, Esq., F.G.S.
(Kead April 12th, 1893.)
[Plate* II.-IV.]
The Cheilostomatous Bryozoa have hardly been recognized with
certainty in the Jurassic series, and Haime mentions two forms of
the Escharidae in his monograph '' with considerable doubt and without
illustration. In the little group dealt with in this paper are mingled
both cheilostomatous and cyclostoraatous features, but the former
predominate, and, for the present, it is desirable to place the group
there. We thus open a field for investigation which will trench
deeply into the ground hitherto occupied by the C) clostomata.
Messrs. Waters, Vine, and Ulrich have written of cheiiostomatous
structure in Palaeozoic fossils ; the English Jura now leads backward
also the relations of this sub-order, and we need to scan this distant
horizon of bryozoan development for signs sufficient to guide us on
our way.
After I had read Part I. of my paper in 1880 I withdrew for
further study two of the species related to those that I am about to
describe. So many of their features were dissimilar to the Entalo-
phora among which I had placed them, similar as they were in
general aspect, that it seemed necessary to find a place for them
elsewhere.
The characters of the two sub-orders Cheilostomata and Cyclo-
stomata merge as we pass backward in time. This merging the
accessory organs of the genus and species here described and figured
will illustrate. Mr. A. W. Waters hus paved the way to the same
conclusion in a recent paper.3 He writes: — 'In the Cretaceous
Melicertitidoe the characters are in the main chilostomatous united
with Rome that are cyclostomatous, and also in a very large section
of Palaeozoic fossils there are important structures similar to those
in recent Chilostomata."
It may ultimately be necessary to erect a new sub-order for the
association of these intermediary forms. When, however, we
understand bettor the various stages of growth and eccentricities of
arrangement of cells, then perhaps the number of genera and
species we have made and are making may be pruned to as moderate
a growth as that to which Dr. Ed. Pergens, in his laborious work,4
1 For Part I., see Quart. Journ. Gcol. Soc. vol. xlv. (1889) pp. 5M-574,
pis. xvii.-xix.
2 ' De*er. des Bryoz. Fom. de la Form, jurass.,' Mem. Soc. Geol. France,
eer. 2, vol. v. (18.M) p. 217.
3 'On Chilostomatous Characters in Mdicertitida' and other Fossil Bryozoa,*
Ann. & Mag. Nat. Hist. ser. ft, vol. viii. (181)1) pp. 48-53, pi. vi.
* ' Ke vision des Bryoz. du Cretaoe figures par d'Orbigny, 1 Pnrtie —
Cvelostomata,' Bull. Soc Beige de Geologic, vol. iii. 186U (Meuioiree), pp. 305-
400.
Vol. 50.] THE INFERIOR OOLITR OP 8HIPT0N GORGE.
73
has so far reduced the prodigality of d'Orbigny's nomenclature.
And yet I write this after giving my leisure hours of the past
three years to the study of the new genus Pergenaia, so named in
recognition of Dr. Pergens's labour of revision.
[Since the reading of this paper I have been aided by the gift of
specimens from Miss £. C. Jelly, the author of a most valuable
* Synonymic Catalogue of Recent Marine Bryozoa.' Lekythopora
and P<xcilij)ora have many points of relationship with the new genus
Ptrgensia. To the general family likeness to the Cellcporidaj 1 had
previously drawn attention, in a comment upon the rostra aud
apertures of one form.
The globose ovieell-sacs of Pergengia find a parallel in the ovicells
of Lekythojwra and P&cilipora, genera which Mr. P. H. Mac-
Gillivray has so well worked out. We notice the same type of
mural and peristomial tubule*, the same deep-seated opercula and
varied zocecial form. At tho same time, it is not possible to escape
conviction as to there being two forms of ovicell : the supra-oral
type, which is a budding of minute cells at the back of tho zoceeium ;
and the ovicell-sac, which is cither iuter-zocecial or borne upon the
zocecial wall. The analogy of the cistern-cell of my Liassic genus
Cisttrnifera to the ovicell-sac is apparent, and in one instance there
npi»ear to be the rudiments of a spouted process as iu Cittern if era.
These lead to the ' cellules accessoires ' of d'Orbigny and possibly
to tho * giant cells ' of Busk aud others.
No author, so far as I know, has commented upon the functions
of the zocecial tubules of Lekythopora, so plainly to be seen in the
specimen with which Miss Jelly has kindly supplied me. Tt has
seemed, in the study of my fossils, that they may develop around
and above the primary aperture. In the Liassic dstemifera a
central tubule is a common feature ; in Ptrgcnsia I have noted it
in the species P. porifera.
Some cells that I have called zooacia, with flat poriferous faces, may
be tho columnar vicarious avicularia of Busk, Waters, and others ;
but there are points of structure, insufficiently worked out, which
make such association doubtful.
The stipe of Istl ylhopora and the mode of growth of the colony
around it explain the cylindrical axis of Pergmgin, aud show that its
' colonial' growth was after the same fashion. — November, 1893.]
Pergensia, gen. nov.
Zoarinm piriform or cylindrical, with a central axial tube round
which the zooecia grow in spiral or irregularly spiral series. Zocecia
tubular, open or with terminal tubules ; ovicells supra-oral. Mural
openings, front or back. Ovicell-sacs : globose, nest-like cells enve-
loping the free ends of zocecia ; irregular swellings of the zoarial
wall, or globose cells borne on the zoarial wall.
Pergkksia kidolata, sp. nov. (PI. II. figs. 1,2; PI. III. figs. 1, 2,
3, 4.)
Maximum zoarial length 4*0 mm., zoarial width 1*1 to 0*5 mm. ;
74
MR. E. A. WALFORD ON BRTOZOA FROM, [Feb. 1 894,
zooecial length 0-5 mm., zocoeial width 0*17 mm.; mouth 0*1 to
0-07 mm.
Zoarium simple, erect, claviform, base narrow (PI. II. figs. 1, 2).
Zooecia tubular, often compressed, springing up closely from the
central shaft, frequently with very long exsert ends, of varying
form. (1) PI. III. fig. 1, mouth ovoid, pore on the lower lip, front
mural pore ; the ovicell is a dome-shaped mass of tubules, with
a larger central tubule projecting from the back of the zocccium :
(2) PI. HI. fig. 2, mouth ovoid, quadrate mural pore at the back,
apertural plate with a large, transverse, ovoid opeuing above, tubules
and a narrow, transverse opening below : (3) PI. III. fig. 4, com-
pressed, ending in two compressed tubular shafts or rostra with a
narrow opening below : (4) PI. III. fig. 3, young, two terminal
processes, a median ovoid opening, lower labial pore.
Ovicell-sacs globose, nest-like in the free ends of the zooecia, enve-
loping two or three ; punctulate, like the zoarial surface, with finer
pores between thera (PI. II. fig. 1).
The zooecia tend to a linear arrangement, as in d'Orbigny's genus
Radiotubigera.
The longitudinal section (PI. II. fig. 2) shows an axial tube of
uniform diameter with thick walls, the primary zooecia lying close
to the tube before trending outward. 8tem sinuous.
The shafts or rostra of No. 3 resemble the rostra of the Celleporida?.
In other species of Pcrgemia the rostrum on one side bears an
avicularium, while on the other side it bears tubules.
Perqensia major, sp. nov. (PI. II. figs. 3, 4 ; PI. III. figs. 11-18.)
Zoarial length 3 to 4 mm., zoarial width 1 to 3 mm. ; zooecial
width 0-3 mm. ; mouth 0*1 to 0*13 mm.
Zoarium erect, piriform, base narrow. Zooecia tubular, springing
at regular intervals from the stem outwards ; exsert parts of excep-
tional length (1 ram.). See PI. II. tig. 4.
Zooecia: (1) PI. III. figs. 17, 18, terminal, with a recessed tri-
foliate or sub-crescentic aperture, supra-oral poro and ovicell-
tubules ; peristomial aperture hexagonal, with thick raised border :
(2) PI. III. figs. 14-10, zooceia lengthened, front wall notched or
areolated, supra-oral oviccll-tubules, mouth-plate with several open-
ings : (3) PI. III. figs. 11-13, mouth with terminal tubules and
transverse labial opening.
Ovicell-sacs : ovoid, urn-shaped, or irregular. The common form
is ovoid, with tubular termination as in Crista. Zoarial surface
covered with the protruding ends of pore-tubes, between which are
liner pores.
The apertural plate is often pierced with pores, as in Busk's genus
Cahjmnophora. Zooecial covers are scattered sparsely about the
zoarial surface.
Perqensia minima, sp. nov. (PI. II. fig. 12 ; PI. III. figs. 5-10.)
Zoarial length 2*0 mm., zoarial width 1*0 mm. ; zooecial length
0*33 mm., zooecial width 0-13 mm. ; mouth 0-07 mm.
Zoarium erect, piriform, beginning with a thin cylindrical stem
Digitized by Google
Vol. 50.]
TFIF IN KF.RIOB OOLITE OF 8HIPT05 GORGE.
75
bearing few zocecia, tlicD suddenly increasing in size by rapid multi-
plication of zocecia, until a stoutly piriform head of crowded tubes
informed (PI. II. fig. 12).
Zocecia email, slightly exsert, tubular, wrinkled: (1) PI. III.
fig*. 5-8, with ovoid mouth, supra-oral ovicell proceeding from the
back, pore below the lower lip : (2) compressed, mouth ovately tri-
angular, two short proc» sses above, trifoliate opening at the back :
(3) PI. III. fig. 10, mouth ovoid, lip arched, apertural plato with a
transverse ovoid opening and tubules.
The ovicell-sacs are globose swellings enveloping several zooecia.
PI. III. fig. 8 may represent an early stage of one. It bears a fiat
top with a perforated disc.
Pergexsta porifera, sp. nov. (PI. II. fig. 6; PI. IV. figs. 1-5,
1«, 17.)
Zoarial length 3 2 mm., zoarial width 1*0 mm. ; zococial length
1-4 mm., zo<i;cial width 0*17 mm.; mouth 0-1 mm.
Zoarium erect, claviform, the axial shaft protruding from the top
(PI. II. fig. 0). Zocecia arranged in an irregularly linear series,
about six to every annulatiou, tubular, tapering slightly, exsert for
one third of the length.
Zocecia: (1) PI. IV. fig. 3, central tubular opening, process on
each side of tho snpra-oral rostrum, globular process on the lower
lip, mural pore below it : (2) PI. IV. figs. 1, 2, compressed, upper
and lower lip arched, lower lip with pore below, ovicell supra-oral,
springing from the back of the zouecium : (3) PI. IV. tig. 17, young
zocecium at the top of the zoarium, with ovoid mouth, trifoliate
aperture, and pores around it on the inner wall ; small avicularia on
the lower lip : (4) mural pore orbicular, with cover (PI. IV. fig. 5).
Zoarial surface punctate, with fine intermediate pores.
One of the doubtful zoteciul form9, resembling a columnar avicu-
larium (PI. IV. fig. 16), appears to have a cover, through which tho
tubules below can be seen.
Ptryensia porifera is closely related to P. nidulata, but as yet
the ovicell-sacs have not been found.
Pergexsia amphoralis, sp. nov. (PI. II. fig. 8 ; PI. III. figs. 21-
24.)
Zoarial length 4'0 mm., zoarial width 1*0 mm. ; mouth 0*07 mm.
Zoarium erect, claviform to cylindrical, axial tube protruding at tho
base and summit (PI. II. fig. 8). Zocecia sub-immersed, or free for
half their length, crowded, equidistant, arranged in vertical lines or
irregular, about sixteen to a volution.
Zooecia : (1) PI. III. fig. 21, upper lip arched, ovicell at the back,
aperture ovoid, recessed: (2) PI. III. fig. 24, compressed, front lip
notched, or the wall areolated ; mouth ovoid, with tubules. Front
mural pore.
Zocecial coverings, pitted with the impress of tubules, occur
detached on the zoarial surface. Clusters of tubuli are to be seen
between the zocecia in one or two specimens. The ovicell-sacs have
not been found.
76
MR. E. A. WALF0RD ON BRYOZOA FROM
[Feb. 1894,
Var. a.—Vl IT. fig. 5.
Young, amphora-shaped.
Zwccia: upper lip archod, with pore, recessed ovoid npcrlurc,
lower labial pore, short side-processes, sessile mural avicularium.
Ovicell supra-oral, proceeding from the back of the zoeeeium.
Ovicell-sacs not known. Upon the front wall of certain zocecia is
traced a large scar.
Pergkxsia jug ata, sp. nor. (PI. II. figs. 9, 10 ; PI. IV. figs. 0-13,
18-21.)
Zoarial length .5-0 mm., zoarial width 1*0 mm. ; zocccial width
0*12 to 0*15 mm.; mouth 000 mm.
Zoarium dumb-bell hhaped, axial tube protruding at each end.
Zocecia diverging from the constricted central part in apparently
linear series or in spiral, often irregular lines (PI. II. tigs. 9, 10).
Zoa_>cia tubular, tapering, or compressed, some placed sideways
upon the zoarium, frequently with long exsert parts: (1) PI. IV.
figs. 7, 10, 11, couoidal, compressed, placed sideways upon the
zoarium, front having a long transverse opening below and other
openings above, with tubules; summit open, with tubules: (2) PI. IV.
fig. 12, compressed, mouth ovoid, wit h lobed superior and ovoid in-
ferior openings ; ovicell at the back : (3) PI. IV. fig. 9, mouth ovately
triangular ; upper lip arched, with pore, lower lip straight, with
pore. Clusters of tubuli occur between the zocccia (PI. IV. fig. 0).
Ovicell-sacs (PI. IV. figs. 8, 20) common, inflations of the zoarial
surface or cells, enveloping several zocecia, generally globose : upper
surface often flat, the whole pierced and slashed with zocecial and
other openings.
Zoarial surface punctate with protruding pores, wrinkled where
the zocecia are few, the whole covered by an outer film pierced with
fine pores.
The longitudinal section (PI. II. fig. 10) illustrates the divergent
growth of the zocecia from the central part and around the axial
tube. In the piriform central cell at the base are numerous reddish-
, brown, globular, crystalline bodies (PL IV. fig. 19). The axial tube
also contains some reddish-brown crystals. Sections cut partly
through and viewed as opaque objects are great aids in zocccial study,
and illustrate well the mode of growth (PI. IV. fig. 21). Some
details can often be seen by staining the specimen.
Pergensia jtgata, var. bi-gibbosa, nov. (PI. II. fig. 11 ; PI. IV.
figs. 14, 15.)
Same form as P, jugata, with slightly stouter zocpcia. Primary
aperture coarctate (PI. IV. fig. 14) with ovoid peristomial aperture ;
avicularium on the side of the zooecium : ovicell-sacs cordate, or
in the form of irregular cells or swellings (PI. IV. fig. 15).
Pergexsia galeata, sp. nov. (PI. III. figs. 19, 20, 25-33.)
Zoarial width 13 mm. ; zooecial length 1*0 mm., zoo&cial .width
0-1 mm. j mouth 0*09 mm.
Vol. 50.]
THE INFERIOR OOLITE OP 8HIPTON GORGE.
77
Zoarium erect, cylindrical, of nearly equal thickness throughout.
Zocecia tubular, obscurely arranged in a linear series, often com-
pressed, eisert for one half or more of their length (PL III. fig. 27).
Zooecia: (1) PI. III. fig. 33, upper lip arched, aperture coarctate,
peristomial aperture ovately triangular, thick : ovicell supra-orul,
front mural pore triangular: (2) PI. III. fig. 30, compressed, mouth
filled with tubules, front wall having a furrow and a narrow ovoid
opening ; at the base an oval opening with very fine tubules
(? ovicell): (3) PI. III. figs. 25, 20, compressed, with two terminal
rostra — one with tubules, the other with a narrow opening, a small
opening at the junction of the rostra, an ovicell- sac or opening at
the ba««e, as in LekytUopora hystriv, MucGil.
Zooecial covers (PI. III. tig. 2fJ) are scattered on the zoarial
surface, whether pushed off at a certain stage of development, or
sheared off in fossilization, it is hard to say. Surface punctate, with
fine inter-pores.
The twin rostral processes spring from above a central opening
or aperture, and are similar to the twin rostral processes of Ctllepora
httMtiycra, Busk.1
Summary.
1. The discovery in the Inferior Oolite of the South of England
of bryozoa belonging to the Cheilostomata, a sub-order not definitely
known below the Cretaceous group.
2. The occurrence in the same colony of bryozoa having the form
of ovicell and long tubular zocecia of the Cyclostomata, together with
the appendages and apertures of the Cheilostomata.
3. The description of a new genus Pergeiuria, characterized by a
long cylindrical axis, globose ovieeU-sacs on the body of the
zoarium and supra- oral ovicell, zococia with trifoliate opercular
aperture or with various openings and tubules.
4. The description of the following species : —
Peajensia nidulata, P. major, P. minima, P. porifera, P. ampho-
rality P. jugata, P. jtKjata var. bi-gibbosa, and P. yaleata.
EXPLANATION OF PLATES II.-IV.
Plate II.
Fig. 1. Pergentda nidulata, sp. hot. x 12.
2. „ „ Longitudinal lection, showing the axial tube. Xl2.
3. „ major, sp nor. Longitudinal section, showing the axial tube
and ovicell-sao with termination. X 12.
4. „ X 12.
5. „ amphvraiis, sp. nov., var. a. X 25.
ft. „ porifcra, Bp. nor. x25.
7. „ sp. Longitudinal section. X20.
8. „ umphoralh, sp. nov. X 12.
ft. n j"9«t<t, »p- nov. x 12.
10. „ „ Longitudinal section, showing the axial tube and direr-
gent growth of zocecia. X 12.
11. „ „ var. bi-yibboM. X 12.
12. „ minima, sp. nov. X 12.
1 By Mr. R. Kirkpatrick'a courtesy I was enabled to eximine Busk a types
in the British Museum (Natural History), at South Kensington.
73 BRYOZOA FROM 8HIPTOX GORGE. [Feb. 1894,
Plate III.
All the figures in this Plate are magnified 50 diameters, except fig. 27,
which is X 1*2.
Fig. 1. Zocecium of Pergensia nidulata, sp. nov. with supra-oral Oficell.
2. „ „ „ with apcrtural plate.
3. „ „ „ joung.
4. „ „ „ with rostral processes, broken.
5. „ Pergensia minima, sp. nov.
0. „ „ „ with supra-oral ovioell.
7, 8, 9. Zocecia of „ „ 7 and 8 viewed from different points.
10. Zocecium of „ „ with apertural plate.
11,12, 13. Zo<ecia of Pergensia major, sp. uov. 12 and 13 : the same zoo?cium
viewed from different points.
14. Zocecium of „ „ with notched lip.
15. „ „ „ with mural opening at the back.
10. „ »>
17, 18. Apertures of ,, „
19. Zixecium of Pergensia galeata, sp. nov.
20. „ „ „ with tubules.
21 . 22, 23, 24. Zoo»cia of Pergensia amphoralis, sp. nov.
27. Prgensia galea ta. sp. nov.
25. Zoceciutn of Pergensia galeata, with rostral processes and opening.
20. „ „ „ like fig. 25, but with basal (ovieell ?)
opening.
2°. „ „ „ with termination displaced.
L8, 30, 31. 32. Zoo? Ma of Pergensia galeata.
33. Zooecium of Pergensia galeata, with mural pore.
Plate IV.
Fijs. 1,2. Zocecia of Pergensia porifera, pp. nov. x50.
3. „ „ „ with broken mouth. X50.
4. Zocecium of „ „ with mural pore. x50.
f>. „ ,, with mural pore and cover. Xf>0.
C. Zocecia of Pergensia ji'gata, sp. nov. with dusters of interzocrcial tu-
bules, x 50.
7. Zocecium of „ „ „ terminal tubules & mural open-
ings. X 50.
8. Ovicell-sac of „ „ X-r0.
9-13. Zocecia of „ „ X50
14. Ovicell-sac of Pergensia jugata, var. bi-giU>om, nov. X 50.
15. Zoo'cium of ,, „ ,, „ X50.
1 6. A vieularium (?) of Pergensia jwriftra. X 50.
17. Zcfcrcium of „ „ X 50.
18. Pergensia jugata. End of zoarium, showing the compressed termination
of the axial tube. X25.
19. „ „ Longitudinal section, showing globose crystalline
bodies in the cell and the axial tube. X 100.
20. „ „ Oficell-sac. X50.
21. „ „ Longitudinal sect inn, partlv cut through and viewed
as an opaque object, to show the cell-arrangement
above the axiul lube. X 15.
Discussion.
The Presidkxt said that this was a paper which could be appre-
ciated only after it was printed. Great interest attached to it,
because the Author described a genua which blends together two
sub-orders.
i
Quart Joum.Geol. Soc . Vol. L . PI . II
Z A W„lford cUi F H Michwl hiK . MmLem. Bros ^
INFERIOR OOLITE BRYOZOA.
Digitized by Google
Quart. Joupii.Geol. Soc . Vol . I. . ?I. HI.
£ A V^roi d del f H TyTicKiuel hth M,nt«rn Bra* . imp ,
INFERIOR OOLITE BRYOZOA.
Digitized by Google
Quart. Journ.Geol. Son Vol. L 71. IV
E A W*Jfoi"d dr\ r H MjcKitel kth. Mmterti bio* imp
INFERIOR OCLITS BRYOZOA. o^ized by Google
Vol. 50.]
BBTOZOA FROM THE MIDDLE LIAS
79
7. On Cheilostomatous Uryozoa from the Middle Lias.
By Edwin A. Walford, Esq., F.G.S. (Read June 21st, 1S9&)
[Platm V.-VII.)
I described in 1887, in my 4 Notes on some Polyzoa from the Lias,' 1
what then appeared to be a well-marked cyclostomatous form of
bryozoa under the name of Tubulipora ittconstans. Since then, I
have detected and have recently mado known the prosence of cheilo-
stomatoos species iu the Inferior Oolite, and after long periods of
search I have acquired more perfect specimens of the Middlo Lias
bryozoa. The exquisite preservation of theso Liassic fragments enables
me, without doubt, to carry back the presence of the sub-order another
stage in geological time, and to add another link towards the better
understanding of the doubtful forms of the Paheozoie rocks.
At first 1 was inclined to associate the species with d'Orbignv's
genus EUa ; but the long tubular zooccia, the orbicular as well as
the apparently triangular apertures, the ovoid opercula, and the
cistern-shaped cells show that the species must be placed elsewhere.
Nor does the modern reading of the genus Lepralia allow of the
inclusion of these forms, though there are points of relationship.
Hence it becomes necessary to add a new genus to an already
over-burdened nomenclature : for this, then, I select the name
C'isterniferay from the shajK} of certain giant cells found thereon.
Their relationship to the cyclostomatous ovicell is probable. Further-
more, in some of the so-called Diastoponr in my collection from
the Great Oolite of Oxfordshire I have detected similar ovicells
(PL V. figs. 14 and 15), and I should say that those of Berenicea
Archiaciy Haime, are undeveloped forms of kindred cells. That
author, in his excellent monograph, writes : — 44 Dcs masses calcaircs,
trois ou quatre fois plus grosses que les testules, lis.ses et de formo
ovalaire, sont eparses a la surface entre les testulos et dans la nieme
direction que celles-ci. Ce sont vraisemblablement les restes des
capsules ovariennes.'' 2 His species came from the Inferior Oolite
of Longwy and Plappeville-les-Metz. There can bo no doubt that
a considerable section of such diastoporidian forms will need to be
transferred to the Cheilostomata, but not until long- continued
search shall have yielded really good enough specimen*.
All the forms described are from the marlstone rock-bed of tho
Middle Lias (zone of Ammonites gjnnattts), King's Sutton, North-
amptonshire, and are in my own collection. Siwcimens of the typo-
form were also found in Mr. \V. Lovell's quarry, when tho stone
was quarried for iron ore, by Mr. Lines Griftin, F.K.C.S. The excel-
lence of preservation is due to the material having been enclosed in
1 Quart. Jo.im. Oeol. Hoc. rol. xltii. pp. G32-TWK», pi. xxv.
1 ' Descr. des Brvor. h\m. de In Form, juraas.,' Mcin. Guol. Soc. Frnnce
■er. 2, rol. t. (1854)' p. 180, pi. iv. fig. 11.
80
MR. E. A. WALFORD OH CDTEILOSTOMATOUS [Feb. 1 894,
concentric layors of dense ironstone, an evidence also of the early
segregation of the iron. Equally well-preserved fossils have been
occasionally found, the most remarkable being the leucoid sponge,
with its delicate network of spicules, Leucatidra Walfordi, described
by Br. G. J. Hinde (Ann. & Mag. Nat. Hist. ser. 6, vol. iv. 1889,
pp. 352-337 & pi. xvii.).
ClSTERXIFERA , gen. nov.
Zoarium foliacoons and bilaminate, or erect, ramose, and cylin-
drical. Zooecia long, tubular. Aperture ovoid. Ovicell supra-oral.
Giant cistern-cells in the zoarium.
Cisternifera inconstans, Walford. (See Quart. Journ. Geol. Soc.
vol. xliii. 1887, pp. 033-634, pi. xxv.) (PI. V. figs. 1-8, 16, 17.)
Zoarium erect, foliaccous, bilaminate, with flattened or cylindrical
branches ; or unilaminate and irregular.
Zooecia radiating fan- like from the base, tubular, lengthened,
with proximal ends free.
Secondary aperture orbicular or ovoid ; tube thin, often lengthened.
Apcrtural plate, with central infundibuliform opening, clithri-
diate in the early stage ; ovicell-tube opening at the superior border,
ovoid operculum at the lower border (PI. V. fig. I). The plate is
pitted here and there, and frequently bears raised openings on the
right and left of the central opening. Upper lip of certain zooocia
arched, bearing an avicularian cell (PI. V. tig. 2). The ovicell-tube
passes through the back of the zocecium, and communicates with a
hyaline ovicell, faint traces of which are seen on the walls of the
zocecium above (PI. V. figs. 3, 6). One or two pores below the
lower lip (PI. V. fig. 1).
In another specimen, from which figs. 5 and 8 are taken, the
infundibuliform opening varies from the contre to the lower part
of the plate, and communicates apparently with a tubule, as in the
latter figure.
Cistern-cells not found as yet on this form.
The zooecia are separated by raised violet^colourcd margins, and
bear numerous serried folds down the centre.
ClSTBRNIFERA INCONSTAN8, FORMA PRIMA. (PI. V. figS. 9-13.)
Zoarium erect, foliaceous, bilaminate. Zooecia lengthened,
tubular, radiating from the base, with long, free proximal ends.
(1) . With an acuto and slightly arched upper lip, bearing an avicu-
larian cell. Apcrtural plate, with a central infundibuliform opening
and an ovicell-tube opening.
(2) . Apcrtural plate, with an ovoid opercular aperture near the
lower lip, two small central perforations, and an ovicell-tubo opening.
Peristome raised, thin (PI. V. fig. 9).
(3) . Aperture ovoid, with an erect or arched rostrum proceeding
from the back, bearing a pore at the apex. Mouth divided into two
Digitized by Google
Vol. 50.]
BUTOZOA FROM THE MIDDLE LI A3.
81
unequal parts, the upper section fronted with tubuli, the lower and
larger section closed by a flat plate pierced with few pores, small
opening at the base. (PI. V. fig. 1 7.)
Central and other tubuli arc shown in worn cells (PL V. fig. 12).
Small avicularium upon the front, wall.
Cistern-cell (PI. V. figs. 10, 11) about three times as long and broad
as the ordinary zooecia, with a broad spout-like process opening into
a thick-lipped, transversely ovoid, basin-shaped recess. Tho whole
resembles a spouted upright cistern in tho zoariura. The spout-
like process is sometimes above, but more generally below the border
of the basin into which it looks. Surface covered with pore-tubes
like the zooecia.
Zocecial margin of a dark purple colour, sometimes raised. Zoarial
surface covered with fine pore-tubes and minute spines.
In Lepralia (?) gyringopora, Keuss, Mr. Waters 1 describes some
* closures * over the aperture having a tubule in tho centre similar
to those of many Diastopora. It appears to be related to tho
infundibuliform opening in my Cistemifera. There are pores on
each side of the central opening in Cisttrniferay and pores on each
side of the centre of the aperture in L. xyringopora. A transverse
oral bar occurs in other forms. Busk figures an infundibuliform
cup in his Clwrizopora Jwnoluhturis,* but gives tho primary oritico
as its origin.
Cistern ifera ircoxstans, forma secttnda. (PI. VI. figs. 14-22.)
Zoarium erect, foliaceous, bilarainate. Zooecia lengthened, tubular,
spreading fan-like from the base, proximal ends free for one-third
of the length.
Secondary aperture orbicular, ovoid or shovel-shaped. In the
latter the upper lip is raised, thin, squared, and bears two pores
(PI. VI. figs. 15, 16, 21).
(1) . Apertural plate with central opening and pores, and ovoid
opercular aperture at the lower lip (PI. VI. fig. 14). Apertural
plate of shovel-shaped zooecia variously pierced (PI. VI. figs. 15, 16).
(2) . Apertural plate with sub-central, oblong aperture and
oviceU-pores. (PI. VI. fig. 22.)
(3) . Apertural plate with sub-central, oval aperture and ovicell-
tube opening. Ovicell proceeding from the back of the cell, and
traced on the zocecial wall at the rear. (PI. VI. fig. 17.)
The cistern-cell is thrice as long and broad as the zooecia, and
has at the top a broad, spout- like process, opening into a transversely
ovoid, basin-shaped recess. It is punctulate : the ordinary zoarial
surface is covered with larger pore-tubes.
Tho zooecia appear to be multiform, apart from the accidents of
fossilization, which make even such good material hard to under-
stand. Some have both upper and lower lips produced. The upper
lip of the shovel-shaped zocecium extends until the apertural plate
1 'North Italian Bryoioa,' Quart. Journ. Geol.Soc. vol.xWii.(1891)pp.20,2l.
4 Buak, Report on the Polyxoa, 4 Challenger' Report*, vol. x. (18S4) p. 149.
a J. G. S. No. 197. o
82
MB. E. A. WALFORD ON CHEILOSTO M 4.TOU8 [Feb. 1 894,
becomes deeply recessed, and the lip ultimately bears a large, quad-
rate recess (ovicellular).
An infundibuliforra opening occurs in the apertural plate of
certain zocBcia (PI. YI. fig. 14). The plate is pore-pierced, and its
lower part and the adjoining part of the lower lip often (where it is
very thin) are broken away, leaving an irregular triangular opening.
Mouth often divided by a transverse bar. (PI. VL fig. 22.)
Cisterni fera inconstaks, forma tertia. (PI. V. figs. 18-21; PI. TI.
figs. 1-4.)
Zoarium foliaceous, bilaminate. Zocecia lengthened, tubular,
proximal ends free for nearly one-half of the length.
Apertural plate with ovioell-tube opening and ovoid opercular
aperture near the lower lip, which is sometimes indented. (PI. V.
fig. 18.)
Upper lip arched and lengthened, with ovicell-tube, or ending in
a thin, squared, vertical, plate-like process pierced with two pores
(PI. VI. fig. 1). Ovicell-tube passing through the back and com-
municating with part of an ovicell traced on the wall of the
zocecium above (PI. VI. fig. 1). A mitre-shaped ovicell with a pore
at the summit is figured (PI. VI. fig. 4).
At the top of the zoarium one of the immature zocecia has tho
upper part covered with a perforated curtain, analogous to the
perforated front of the form figured in PI. VI. fig. 3.
ClSTBRNIFERA INCONSTAITS, FORMA QUARTA. (PI. VI. figS. 5-13.)
Zoarium encrusting. Zocecia spreading fan-like from the base,
and looking towards the upper zoarial surface : tubular, and with
proximal ends free for nearly one-half of the length, marginal
zocecia nearly immersed.
Zocecia with lip arched above an ovicell-tube ; centrally a pore-
tube rounded or irregularly sub-quadrate, bearing a spherical
granular mass pierced with fine pores. Aperture ovoid, with a plain
ovoid operculum near the lower lip. (PI. VI. figs. 5, 6, 7.)
A ribbon-like septal loop occupies the central part of a zocecium
and makes an irregular cell or cup in the mouth (PI. VI. figs. 9, 12).
It seems to be a further development of the central tube.
Worn cells show a central tubule, the base of the ceutral tube.
Cistern ifera clacsa, sp. nov. (PI. VII. figs. 1-11.)
Zoarium erect, ramose, branches cylindrical or flattened. Zocecia
lengthened, tubular, with free proximal ends.
Aperture orbicular or ovoid, peristome elevated.
(1) . Apertural plate with ovoid ovicell-opening and oblong oper-
cular aperture at the lower border, the intervening area with
tubuli. (PI. VII. figs. 2/3, 4, 9.)
(2) . Apertural plate pierced with tubuli in tho upper part, with
an oblong ovoid opercular ' aperturo at the lower border. Ovicell-
tube springing out of tho back of the zocecium, certain zocecia
ending in a triangular apex with a pore at the summit. (PI. VII.
fig. 5.)
Vol 50.]
BRYOZOA FROM TIIE MIDDLE LIAS.
83
Traces of an erect, hyaline, globose ovicoll are present rarely on
the wall of the zocccium above. (PI. VII. fig. 6.)
Cistern-cell about thrice the length and breadth of tho common
zocecia, occupying their place iu the zoarium, vertical, ending in a
broad, spoub-like process, without recess or lower opening. (PI. VII.
fig. 7.) Surface covered with the protruding ends of surfuco-pores
like the zoarium.
[Further study has enabled me to discover a primary plate,
pierced with one opening of varying shape, or with several segments.
It is deep-seated, and the termination or sub-termination of tho
zooecial tube is closed with the apertural plate. Presumably from
the primary plate arises the central tubule, on the upper side of
which are the various tubes and septal divisions making up and
leading to the inner part of the ovicell (one sees the outer or supra-
oral part of the ovicell traced on the zooocial wall). Below tho
central tubule is what I take to be the true zooecial tube which
opens within the mouth. Apparently it turns outwards with the
closing up of the mouth by the mouth-plate with the infundibu-
liform opening, and merges into and becomes a labial aperture. A
scutum (or lip-pore) is traced on the under lip, but it and the con-
nected part of the apertural plate are generally broken away ; see
PL VII. figs. 13, 14. The spherical bodies borne on the tubule of
forma quaria appear to be reproductive. I have been greatly aided
by the study of specimens such as Liripora, of P. H. MacGillivray,
kindly given to me by Miss E. C. Jelly, whom few surpass in
knowledge of bryozoa. The study of the Australian forms
which Mr. P. H. MacGillivray has worked out so well is a clue
to the study of the Jurassic types, for the bryozoan fauna, like the
general Jurassic fauna, finds kindred forms in Australian seas. —
January 24th, 1894.]
In a Diastoporidian form from the Inferior Oolite (Pea Grit) of
Selsey Hill, given to me by Mr. Charles Upton, of Stonehouse, I
have noticed similar giant or cistern-cells.
The beautifully-preserved terminations of the surface-pores are
shown in PI. VII. fig. 15.
In many instances tho zocecia figured are from one zoarium.
EXPLANATION OF PLATES V.-VII.
Plate V.
Fig. 1. Cutern\fera inconstant, gen. & sp. nor. Zooecium with infundibuliform
ming, aperture, and labial pore. x60.
ooe
2. „ „ ZoaH3um with aricularian cell and broken
apertural plate. xOO.
3, ft. „ „ Zooecia with tracery of Bupra-oral ovioell. xOO.
4,5,8. „ „ Zooecia. x60.
7. „ Top ot so&cium, showing the central tubule.
xGO.
9. „ M forma prima. Zocccium with apertural plato
and aperture. xOO.
10,11. „ „ „ Cistern-cells. X60.
12. „ I, „ Zooecium with tubule. x60.
13. „ „ with apertural plate. XOO.
e 2
84 BRYOZOA FROM THE MIDDLE LIAS. [Feb. 1894,
Fig*. 14, 15. Zoopcia and cistern-cells of so-called Diastopora, from the Great
Oolite, x 50.
16. 17. Citternifera inconstant. Zoo?cia(?) with apertural plates. x60.
18. „ „ forma trrtia, with recessed apertural
plate and openings. X 60.
19,20,21. „ „ „ Zoopcia. Figs. 19 k 20
with oral bar. x60.
Plats VI.
Figs. 1. 4. Citternifera inconstant, forma tertia. Zoopcia with traces of supra-oral
ovicell. x60.
2. „ „ n Zoopcium. x60.
3. „ „ „ witli perforated curtain over
mouth of zocrcium. x<?0.
5. Cisternijtra inconstant, forma quarta. Zoopcium with spherical body
covering tubule. X 60.
6, 7. n »> m Zoopcia with apertural plates and
labial aperture. X 60.
8,10,11. „ „ „ Zoom'a. x60.
9, 12. „ „ „ Zooccia with tubules developed
into loops. x60.
13. „ „ ,. Zouriuni. x25.
14. 18. ,, „ forma secunda. Zoopcia with apertural plates and
labial apertures. xGO.
15,16,19,21. „ „ „ Shovel-shaped zoopcia. x60.
17. „ 11 Zoerciuni with traces of ovicell.
X60.
20. „ ,, „ Zocecium. x60.
22. „ „ „ Zoopcium with apertural plate.
X60.
Platb VII.
Figs. 1,5,6. Citternifera clatua, gen. k sp. nov. Zoopcia showing traces of
supra-oral ovicell. x 60.
2, 3, 4, 9. „ „ Zoopcia with apertural plate, ovoid aperture.
XGO.
7. M I, Cistern-cell with spout-like opening, x 60.
8. 1, ti Zoopcium showing the position of the ovicell-
tube from above. X 60.
11. „ „ Zoariura. xl4.
10, 12. „ inconstant. Cistern-cells (flg. 10 shows young cell).
X 100.
13,14. „ „ ZocBcia showing labial aperture. x60.
15. „ .1 Showing the terminations of the surface-
pores. X 200.
16. „ inconstant. X14.
17. „ clausa. X14.
DI8CU88IOX.
Dr. G. J. Hijtde wished to call attention to the remarkably
perfect condition of preservation of the delicate bryozoa described
by the Author, which appeared to have resulted from thoir having
been enclosed in the interior of ferruginous nodular masses, much in
the same way as the fine material in the interior of Chalk flints.
In the same material the Author had also discovered some equally
perfect, almost microscopic calcisponges, which he (the speaker) had
described.
Digitized by Google
Quart. Journ.Geol.Soc. Vol. L Pl.V
E A WaJford W ?H Mich**! lifch Vr.nX.em Eroe imp
L1ASSIC & OOLITIC BRYOZOA. Digitized by Google
A HO
/ 60
Quart. Journ . Geol Soc Vol . L . Pi . V.
,< uo
* 60
a 60
*60
i GO
x 60
< 60
X6C
* 60
S AY/mlW del F H M;ci-^ftl liU
*60
LIAS SIC BRYOZOA.
MitvLerrv k3to« unp
Digitized by Google
Quart. Joum.Geo] . Soc .Vol . L. PI. VII.
LIAS SIC BRYOZOA Digitized by Google
Vol. so.]
THE GEOLOGY OP MATTO GROSSO.
85
8. The Geology 0/ Matto Grosso (particularly the Region drained
hy the Upper Paraguay). By J. W. Evans, D.Sc., LL.B., F.G.S.
(Read November 8th, 1893.)
[Plate VIIL-Map.]
Contents. Pago
I. Introduction 85
IT. Bibliography 8(i
III. Physical Features of Matto Grosso 87
Succession of Strata 88
IV. Pre-DeTonian Rocks 88
"\. Ancient Crystalline Rocks 88
2. Cuyaba Slates 90
-{ 3. Corumba and Arara Limestones 91
4. Rizama Sandstone 93
k5. Matto Shales 93
V. Devonian Rocks (Chapada Sandstones) 95
VI. Carboniferous, Trias, and Cretaceous t'7
VII. Quaternary 98
VIII. Unclassified Rocks 99
IX. Igneoug Rocks 100
X. Historical Summary 101
XL Economic Products 102
[Sole. — The italic numerals in parentheses*, throughout this paper, refer to
the works quoted in the bibliographical list.]
I. Introduction.
I spent some time in this part of South America in tho years 1891
and 1892, but unforeseen circumstances seriously interfered with
geological work. The present paper is the result of such observa-
tions as I was able to mako, and I have to thank the other members
of the expedition (including tho leader, Lieut. 0. T. Storm, of tho
Scandinavian Navy ; his brother, Mr. Johan Storm ; and Mr.
Spencer Moore, the well-known botanist) for doing all that was
possible to facilitate my labours.
Very little has hitherto been known geologically of most of
the country I traversed. A short account of A. d'Orbigny's
valuable work in the adjoining portion of Bolivia in the year 1842
(7) is given in the present paper (p. 90). Castelnau visited Matto
Grosso in 1843-44 (2), Chandless about 1864 (#), tho Brazilian and
Bolivian Joint Boundary Commission in 1875-78 (»5), and Von den
Steinen with Gauss in 1884 and subsequently (6) & (7) ; but they
have not given us any very definite geological information. Several
years ago Mr. Herbert H. Smith resided for about two years in tho
Chapada near Cuyabd, being engaged in zoological collecting. Some
fossils obtained by him were described by Mr. Orville A. Derby
in an important paper in which he summarized all that was then
known of tho geology of Matto Grosso (8).
86
BR. J. W. EVANS ON THE
[Feb. 1894,
The last-named gentleman has kindly perused this paper, and I
have had the bonefit of his observations upon it : they have especial
value on account of his extensive acquaintance with the geology of
other parts of Brazil. I am indebted to Mr. A. M. Davies, F.G.S.,
for invaluable assistance in seeing this paper through the press,
and to Mr. W. Rupert Jones for careful revision of the references
throughout, a task which 1 was unable to undertake myself, on
accouut of my being now resident in India.
The map which accompanies the present paper (PI. VIII.) shows
the routes taken both by Castelnau and by myself, and also the geolo-
gical structure of the country, so far as I have been able to ascertain
it. I have inserted a few details ou the authority of Castelnau, but
it is not easy to gather the exact nature of the rocks from his
descriptions.
II. Bibliography.
a. Publications referred to in this paper in connexion with Matto
Grosso or Eastern Bolivia.
(/) d'Orbigny, Alctdk. ' Vovnge dans rAm^rique Mt ridionale execute pendant
lee annecs 182tl-33,* vol*, iii. S^ne Part i© (G^ologie), Paris, 1842.
(2) Castelsat, Comte Francis dr. 4 Expedition dans lea Pnrtiea Centrales de
l'Am^rique du Sud,' !»•*•« Partie (Histoire du Voyage), vols. ii. & hi. ;
Partie (Itineraires et Coupes Giologiquee) ; 5*me Partie (G^ograpbie) :
Paris, 1850-57.
(<*?) Coasdless, W., Journ. Roy. Geogr. Soc. 180(5.
(4) Lloyd, . . . , ' Caminho do ferro d' Isabel, da Provincia do Parana a [aquella]
de Matto Grosso,' Rio de Janeiro, 1875.
(5) Foxskca, Dr. J0X0 Sevkriaxo da, * Viagem ao redor do Brasil' (two
vols.), Rio de Janeiro, 1*80.
(G) Ci,auhs, Otto, 'Bcricht iiber die Schingii-Expedition im Jahre 1884,'
Petermnnn's Mittheilungen. vol. xxxii. (ISKfi) pp. 129-134, & pp. 162-171.
(This gives an account of K. von den Stetnen's expedition.)
(?) V05 dm Steimen, Karl, * Durch CentmJ-Hraeilien. Expedition Eur
Erforschung des Schingu im Jahre 1884," Leipzig, 1886.
(S) Dekbt, Orville A., ' Nota eobre a Geologia 0 Pnleontologia de Matto
Grosso,' Archivos do Museu National do Rio de Janeiro, vol ix. (1800)
pp. 59-88.
6. Publications referred to in this paper, relating to the geology
of other parts of South America.
(0) IIartt, Charles Frederick, 'Scientific Results of a Journey in Brazil.
By Louis Agussiz and his Travelling Companions. — Geology and Physical
Geography of Brazil ' (Boston, 1870). (J- A. Allew, Notes by, on Country
between Ohique-Chique and Bnhia.)
(10) Derby, Orviklr A., ' A Contribution to the Geology of the Lower
Amazonas,' Proc. Am. Phil. Soc. vol. xviii. (1879) pp. 155-178.
(//) , * The Geology of the Diamantifcrous Region of the Province of
Parana, Brazil,' V>. pp. 251-258.
(12) , ' Modes of Occurrence of the Diamond in Brazil,' Am. Journ. 8ci.
sor. 3, vol. xxiv. (1882) pp. 34-42.
(IS) , 4 Physical Geography and Geology of Brazil.' This appeared in
the ' Rio News ' (Dec. 5th, 15th, & 24th, 1884). and was republished as a
pamphlet. It is an English translation of chaps, iv.-vi. in vol. 1 (A
Geogrnphia Pbysica do Brasil) of 4 0 Brasil Geugraphico e Historico,' por
J. E. Wappaeus (8vo, Rio de Janeiro, 1884).
Digitized by Google
Vol. 50.] GEOLOGY OP MATTO GROSSO. 87
(14) Pohlmasit, Robert, 'Gesteine aus Paraguay,' Neues Jahrb. 1886, vol. i.
pp. 244-348.
(15) Debut, Orvillk A., 'On Nepbeline- Rocks in Brazil. [Pt. I.] Quart. Journ.
Geol. Soc. vol. xliii. (1887) pp. 457-473.
(16) , ' On the Magnetite-Ore Districts of Jacupiranga and Ipanema, Sao
Paulo, Brazil,' Am. Journ. Sci. ser. 3, rol. xli. (1891) pp. 311-321.
(17) , * On Nepheline-Rocks in Brazil.'— Pt II. Quart. Journ. Geol. Soc.
toL xlvii. (1891) pp. 251-265.
c. Other papers referred to.
(18) Barbour, Erwu H., and Joseph Torrey, Junr., 'Notes on the Micro-
scopic Structure of Oolite, with Analyses,' Am. Journ. Sci. ser. 3, vol. xl.
(1890) pp. 246-249.
(19) Vas dex Brorck, Er*est, • Les Oailloux Oolithiques des Graviers Tcr-
tiaires des Ilauts Plateaux de la Mouse,' Bull. Soc. Beige de Geologic
vol. iii. (1889> pp. 404-410.
(20) Whtmper, Edward, • How to use the Aneroid Barometer.' London, 1891.
(21) Gregory, J. Walter, « The Physical Features of the Norfolk BroaUs,'
Natural Science, vol. i. (1892) pp. 347-355.
III. Physical Features of Matto Grqsso.
Matto Grosso ia the second largest of the Brazilian States. Its
area exceeds 2 million square kilometres 1 (about half a million
square miles). It is adjacent to Bolivia and Paraguay, and
holds as nearly as possible a central position in the South American
continent.
The centre of the Stato is occupied by an undulating tableland,
rising in places to more than 800 metres (2600 feet) above sea-
level.3 It extends from the south-west of the State of Goyaz in a
west-north-westerly direction to the cataracts of the Rio Madeira, just
above its junction with the Rio Mad re de Dios. The eastern
portion is called the Chapada, a name commonly applied in Brazil
to tablelands like this with precipitous sides. Farther west, tho
steep southern margin is known as tho Serra dos Parecis (from tho
Indian tribe of that name) and the Cordilheira Geral.
On the northern boundary of the plateau we find the head-
waters of the Araguaya, Xingu, and Tapajos, which flow northward
into the Amazonas. Tho southern drainage is performed partly by
the Guapore, a tributary of the Madeira (which above the point of
confluence is known as the Marmore), and therefore of the Amazonas,
and partly by the numerous tributaries of the Upper Paraguay.
This tableland is believed to sink more or less gradually to the
northward into the Amazonian plain, while on the south there is a
1 The official unit of distance is the kilometre, but the Brazilian league of
6*6 kilometres (4*1 English miles) is often used.
2 Calculations from the author's aneroid readings near the village of Sant*
Anna da Chapada gave a height of 880 metres or 28t>0 feet ; but no doubt some
deduction miut be made from this estimate, on account of the progressive changes
which Mr. Whymper has shown to take place in an aneroid when it is
under diminished pressure: see (20) p. 58.
8S
THE GKOLOOT OF MATT0 G ROSSO
[Feb. 1894.
sudden descent to a lower, but still hilly region usually less than
300 metres (about 975 feet) above the sea.1
Farthor south this hilly country is replaced by extensive marshy
plains continuous with the lowlands of Bolivia, the Paraguayan
Chaco, and the Argentine plains, and extending with but little in-
crease of elevation to tho Bolivian tributaries of the Amazonas.
From these alluvial tracts rise here and there a number of rock-
masses of various dimensions, from the extensive highlands of the
Chiquitos to isolated eminences of insignificant proportions.3 But
in the east the high land of the Chapada continues southward
and connects with the hills of Paraguay.
The majority of the rocks in Matto Grosso may be tabulated in
the following manner. The correlation of strata in different locali-
ties must, in the almost entire absence of fossils, depend to a large
extent on lithological characters — an unsatisfactory basis, but all
that is at present available. I am responsible for the names of
Nos. 2 to 0 ; I have not seen rocks 7 to 9.
Quaternary 10.{^v^ . -f
(High-level surface-depostts.
Cretaceous ? 9. Sandstones of the Taboleiros.
Trias ? 8. Sandstone, with igneous rocks, near Miranda.
Carboniferous? ... 7. Shales, with fossil ferns, near Miranda.
Devonian 6. Chapada Sandstones and Shales.
(Probable unconformity.)
(b. Matto Shales.
(Relations not shown.)
4. Rizjima Sandstone.
(Ferbaps some unconformity.)
Pre-Deyoniah { 8. Corumba and Arara Limestones.
(Verv marked unconformity.)
2. Cuyaba Slates.
(Strong unconformity.)
k 1. Ancient cryslaLiue rocks.
(As yet unfossiliferous
and of unknown age.)
IV. Pre-Devonian Rocks.
1. Ancient Crystalline Rocks.
Theso occur in situ at TJrucum, near Corumba'. Pebbles of
similar rocks aro found at various points in the Cuyaba Slates. The
Urucum rocks are foliated and schistose in appearance; though
Prof. Bonney, who kindly examined specimens and thin sections of
them, thinks that they arc really of igneous origin, but have been
crushed and sheared so as to take up their present structure. Some
1 Clauss, from daily barometric readings extending over about two months,
calculated the height of Cuyaba as 201 metres or Go3 feet, (*>') p. 168. My
aneroid observations, made at Santa Cruz (Barra dos Bugres) on tbe Bio Para-
guay, about l.r>° S. lat, show the Paraguay there to bo a little higher than the
Kio Cuyaba at Cuyaba. I found the foot of the Chapada north-west of Cuyaba
to be at a height of about 320 metres or 1040 feet above sea-level.
9 The height of the Paraguay at Corumba, and therefore practically of the
low plain adjoining, appears to be about 120 metres or 400 feet : see (£) p. 22.
00
DR. J. W. EVANS ON THE
[Feb. 1894,
were probably granites originally, others appear to be derived from
gabbros or other basic rocks.
At Cacurisal, on the western bank of the Rio Paraguay, a little
north of its junction with the Sao Lourenc_o, are found some much
decomposed crystalline rocks. They are more or less schistose, and
consist of quartz-grains often minute, small flakes of white mica,
and other white decomposition-products. These rocks are appa-
rently of igneous origin, like those at Urucum. Farther south, at
Dourados, arc rocks of a similar character, as well as quartzites.
I nowhere saw undoubted gneisses or crystalline schists.
D'Orbigny states that he found them in the Chiquitos in Eastern
Bolivia (see infra, p. 96). They occur widely in Eastern Brazil.
2. Cuyaba* Slates.1
These aro highly cleaved clay-slates, apparently of great thickness,
though the beds are no doubt repeated by folding. They often
contain crystals of pyrites, usually very minute.
The slates extend from Cuyaba north-eastward to the foot of the
Chapada plateau, where they are covered unconformably by the
Chapada Sandstones. In this direction they aro much decomposed,
being sometimes as soft as clay.' They usually dip north-west at
40° to 55°. In some places the stratification can be distinguished
from the cleavage, and dips at a lower angle.
North-west of Cuyaba the slates extend across the Rio Cuyabtf,
and the dip increases till it is vertical, a little south of the
Rio Espinheiro. Farther north-north-west the dip becomes south-
easterly at a high angle, then it again changes to north-west ; but
at the Rio Jangada, whero the rocks are well shown near the
fazenda (farm) of Dom Francisco, they dip to the south-east at 50°.
Beyond this point I found no exposures till I reached the remark-
able series of parallel ridges that run from the Rio Paraguay,
near Sao Luiz de Carceres (Villa Maria), north-eaat-by-north to the
east of Diamantino and west of the upper waters of the Cuyaba.'
In the longitudinal valleys between these hills the slates are again
mot with, dipping very steeply, usually north-west or south-east.
They underlie unconformably the Arara Limestone.
As 1 have already remarked (p. 88), the Cuyaba Slates often con-
1 Similar slates appear to occur in the States of Minas Geraee and Bahia, in
the region drained by the rivers Jequitinhonha and Pardo, especially in the
Serra de Congonha and Sorra do Grao Mogor ; also at Calbao, and thence to
Minas Novas and the neighbourhood, (9) pp. 138-39, 151-64, 157, 163. 242-
43. They usually dip steeply north-west or south-east, as in Mat to G rosso,
and are said by Hartt to resemble the gold-bearing rocks of Nova Scotia
cit. p. 157). These slates are also found in Sergipe (op. cit. p. 405), Ceara
(op. cit. p. 464), and in Goyat near Arrayas (op. cit. p. 498) ; see note, infra,
p. 91. Similar slates were moreover observed by A. d'Orbigny in the Chiquitos
(see infra, p. 96).
2 Hartt met with similar decomposed slates between the Capivary and Minos
Novas, op. supra cit. p. 154.
3 The northern portion of these hills is known as the Serra de Tombador and
Serra Azul, (2) Partie, Map 9.
-
Digitized by Google
Vol. 50.]
GEOLOGY OF ilATTO G ROSSO.
91
tain pebbles of older rocks. These are of all sizes, tip to 8 inches or
more across. They are most plentiful in the north-west, and con-
sist mainly of granitoid rocks, in which shear-foliation was already
developed before they were included in their present matrix. Some
of the pebbles appear to be derived from clastic rocks, and a few
may be fragments of a compact lava-like rock. The pebbles are
sometimes isolated, sometimes a great number are found together :
but each is embedded in the fine-grained matrix of the slate, the
divisional planes of which opon out, so to speak, and envelop it. In
exposures in the channel of the Rio Jangnda tho slate contains
abundant fragments of these materials, which in some places make
up one half of the rock. Occasionally (as, for example, about half-
way between the Rio Espinheiro and the Rio Jangada) grit-beds of
similar materials, but in a finer state of division, occur intorstratified
in the slate, their outcrops standing out like igneous dykes. Prof.
Bonney tells me that specimens of these conglomeratic rocks remind
him of some of the ashy beds in the porphyroid of Sharpley,
Charnwood.1
Castelnau found highly inclined slates with limestone on tho Rio
Miranda, in South-eastern Matto G rosso ; see (£), 1*™ Partio, vol. ii.
I have placed these limestones together, though there is no clear
evidence that they are of the same age ; but there is considerable
resemblance between them.
The limestone of Corumba is well shown in the cliff on which that
town stands. It occupies most of the lower portion of the extensive
island-like elevation, which at this point diverts eastward the course
of the Paraguay.
1 Slate-conglomerate* hare been described from the Caxoeirinha do Rio
Pardo, Southern Bahia, (9) pp. 242-13, and from near Arrayas, Goya*, A.
p. 498. In the latter case the matrix is called by the observer gneiss, but
from the description it would appear to be slate.
3 Limestones of more or lets similar character are described as occurring
in the valley of the Rio Sao Francisco, especially on the eastern side. The
account given of the limestone of the Rio das Velhas (a tributary of the Sao
Francisco) reminds me of that of Arara, while farther north, near Chique-Chique,
the limestone would appear to more resemble that of Corumba. See \'J),
pp. 278, 310-12, 327-28, 331, and {1?) p. 35. Similar limestone appears to be
Ibund in the basins of the Jequitinbonha and Paraguassu in the States of Minas
Geraes and Bahia, (9) pp. 138, 302-3 ; in Goyaz (op. tit. p. 497), and also in the
Chiquitos (see infra, p. 96). I also found a limestone, somewhat like that which
occurs at Corumba, on the eastern bank of the river Paraguay, in the extreme
north of the republic of that name.
According to Mr. Derby, M The specimens of limestone that have come to
hand from Corumba are strikingly similar in aspect to the limestones of Sao
Paulo and Parana that occur in a series that is certainly pro-Devonian, and is
older than a similar but apparently less metamorphosed series in the Sao
Francisco basin in which some obscure fossil corals, apparently of Upper
Silurian type, were found by tha writer at Bom Jesus da Lupa," (8) p. 72.
p. 466.
3. Corumba* and Arara Limestones.8
i)2
DR. J. W. EVAITB 03T THB [Feb. 1 894,
The limestono is, when purest, dark blue in colour. It passes into
paler and more argillaceous beds, and sometimes into a yellowish
Cidcareous shale : it is often siliceous. The dip is usually from 10°
to 15° north, but frequently near the margin changes, so as to be
directed towards the alluvial plain.
This limestone is also found at low elevations, rising out of the
plain north and east of Corumba, as, for example, at Castelhos and
near Carandazinho 1 on the Rio Paraguay.
Behind Corumba there occurs in the limestone a thick deposit of
ferruginous chert. Its superior hardness gives rise to a long ridge
at the back of the town some hundred metres high.2 Near Corumba
the limestone is sometimes brecciated and re-cemented, and I found
specimens showing this re-cementod material aud also the normal
rock silicified into a kind of flint.
At Coimbra is found an impure limestone, often yellowish or red
from the presence of iron. Some varieties appear to be dolomitic,
as they only effervesce with hot hydrochloric acid. I paid a short
visit to a large cavern in this limestone about 5 or 6 kilometres
(3 to 3| miles) north of Coimbra. It has been often described ; see
(£), l*re Partie, vol. ii. p. 400, and (5) vol. i. pp. 271-285. It has
extensive ramifications and numerous stalactites ; the floor is gene-
rally composed of a ferruginous sand, the residue left after the
removal of the carbonate of lime from the limestone.
The Arara Limestone occurs in the parallel ranges of hills already
referred to (p. 90) between the upper course of the Paraguay and
the llio Cuyaba, especially at Arara, an isolated hill at the northern
end of the most easterly ridge. It is also found in the adjoining
range to the westward. South-west of Chapedon, in the valley
beyond, is an isolated natural turret of limestone, the rest having
been removed by denudation.
This limestone is pale and streaky, rather more compact and
altered than that of Corumba. Close to Arara it usually dips at
about 15° to the south-west, but is in some places much contorted.
Farther west it is nearly horizontal, while the Cuyaba Slates have a
steep dip. As a result of weathering, exposed surfaces of the Arara
Limestone become studded with acicular points.3
I was unable to find any organic remains in the Corumbd or
Arara Limestones ; but I was told at Sao Luiz de Carcerea that
limestone containing shells is found in the hills east of that town,
viz. the southern extension of the hills in which Arara Limestone
occurs. It is, of course, possible that these shells are land-mollusca,
embedded in travertine of comparatively recent formation.
1 Near this locality I noticed a large stream flowing into a low cave, at the
base of a liinestone-hill.
3 Compare the chert stated to occur in the neighbourhood of VolU da Serra,
near Jacobraa, in the State of Bahia. It is there called pedra de fogo o/fi re-
stone, (S) p. 312.
3 The same effect of weathering has been noted at Chique-Chique : see (?)
p. 310.
Vol. 50.]
GEOLOGY OF MATTO GROSSO.
93
Limestone is also found in the same range of hills north of Arara,
near Diamantino, and still farther north ; see (2), lire Partie, vol. ii.
p. 302.
The limestono occurring hotween Sao Luiz de Carceres and the
Registro do Jauru, (2) 4*** Partie, pi. 52, may perhaps also belong
here.
In the uppermost Paraguay, near Santa Cruz, Barra dos Bugres, I
found some curious pebbles of silicifiod pisolite and oolite, not im-
probably derived from another exposure of the Arara Limestone.
The structure is well shown in thin sections. Hartt found pebbles
of an apparently similar rock at Aracare, a prominent rocky point
lust below Villa Nova in the State of Sergipe, on the Sao Francisco,
near its mouth, (9) pp. 396-97.1
4. Rizama Sandstone.9
This sandstone overlies the Arara Limestone, to which it is appa-
rently somewhat unconformable. It is an altered and indurated
felspathic rock, very different from the Chapada Sandstones, and
is well seen in the line of hills (one of the parallel ridges already
referred to) which terminates near the little settlement of lii/ama,
about 55 kilometres or 34 miles (following the bridle-track) east of
Santa Cruz, Barra dos Bugres. This range is divided down the
centre by a narrow longitudinal valley, which appears to extend
for many miles. The same sandstone is found in the adjoining
ranges to the east, and also south-west, where one of these parallel
ridges abuts on the Rio Paraguay a little above Sao Luiz de Carceres
(see Map, PI. VIII.).
5. Matto Shales.
These are mainly found west of the uppermost Paraguay, north
of its junction with the Rio Sepituba. They appear, however, to
occur in the bed of the Rio Jacuara, an eastern tributary of tho
Paraguay. I could not observe the relations of these shales with
1 Silicifled oolite has also been described from the Assynt Limestone at
Stronechrubie, Uamh Valley, Durness ; from Centre County, Pennsylvania, (IS)
p. 249 ; and from the neighbourhood of Namur, Belgium, where pebbles of
silicifled Jurassio limestone occur in Tertiary deposits, (19) p. 404. [I am in-
debted to Prof. J. W. Judd, F.R.S., fur these references, and the opportunity
of seeing hand -sped mens and thin sections from the localities mentioned.]
9 I do not know whether the Rizama Sandstone is represented elsewhere in
Brazil. Possibly the compact quartzose sandstone, that unconformably over-
lies the limestone ' at Olhoe d* Agua, about seventy -five miles west of Jaoobina,'
(9) p. 311, may correspond to it, and not to the Devonian Sandstone of the
Chapadas of Matto Groaso and elsewhere. The Rizama Sandstone certainly
appears to occur in the Chiquitos (see infra, p. 9(5). In stratigraphical
position it may be compared with a great sheet of sandstone in Northern Minas
Ueraes and Central Bahia, described by Mr. Orville A. Derby as bent into
broad simple folds and lying unconformably on the upturned edges of the
Huronian and Laurentian, (12) p. 34, (13) p. 5 ; but he tells me that this sand-
stone does not in any way resemble a specimen of the Rizama Sandstone which
I sent bim.
DR. J. W. EVANS OX THE
[Feb. 1894,
a
©
£
11
Hi
.0 c
O ©
3^
eS
.2
. ©
O «H
c: c
.5 ©
t- —
► .9
a-s
!I
c
S —
«
c
3
.8
f
J
the Rizama Sandstone, because
the country between Rizama and
the Rio Paraguay is mostly
covered by recent deposits and
vegetable soil.
None of the rocks previously
described in this paper afford very
fertile soil: the ground is gene-
rally lightly timbered, and the
vegetation suffers severely from
want of water during the dry
season, so that the country has
then an almost wintry aspect.
The transition to the Matto Shales
is marked by the incoming of a
continuous forest (matto) of lofty
trees, beneath whose shade grows
the poaia (as ipecacuanha is locally
called), tho roots of which are the
principal export from the State.
Even towards the end of the dry
season these trees preserve their
leaves, and many of the streams
continue to flow.1
The Matto Shales can be well
studied in the neighbourhood of
the settlement of Santa Cruz,
Barra dos Bugres,2 already re-
ferred to. There they undulate
in gentle curves, but are re-
peatedly disturbed by reversed
faults. Some of these faults are
well shown in the fine section on
the right bank of the Paraguay
about 6 kilometres or 3| miles
above Barra dos Bugres (see fig. 2).
The shales are red, with streaks
and patches of white. They are
comparatively soft, and have a
greasy feol. Lamin® of calcite
occasionally occur in them.
In travelling up the Paraguay
from Barra dos Bugres, exposures
1 This forest, or an exteusion of it,
appears to furnish the explanation of
the name Matto Grosso ('thick forest"),
(6) vol. ii. p. 1.
3 Barra dos Bugres means ' the mouth
of the Rio dos Bugres,' so called from
the Bugres Indians.
Vol. 50.]
GEOLOGY OF MATTO GROSSO,
95
of these shales and occasional interstrafcified grit-beds are seen at
intervals. A steady dip of about lo° north-north-west soon sets in,
and continues as far as the neighbourhood of Tres Barras.1 Here
the Bio Sant' Anna joins the Paraguay, which has just received the
Rio Brumada. I followed the shales for a short distance up the
Rio Santf Anna (where they dipped at 10° north-north- west), and
also up the Rio doe Bugres and its tributary the Rio Brazinho.
Along the two last-named rivers the shales were more horizontally
bedded.
I was informed by reliable Brazilian traders that similar shales
are found on the Rio Sepituba, and rod argillaceous shales are de-
scribed by Castelnau as occurring near Diamantino, (2) 1^° Partie,
vol. ii. p. 323.
I travelled by land about 100 kilometres (or 62 miles) north-west
of Barra dos Bugres. No exposure of the shales is met with in the
forest, but the nature of the soil and vegetation indicates their con-
tinuance till the hills of Tapirapuain are approached. The soil then
becomes ferruginous, and the trees smaller and fewer, till a tract of
peaty grass-land is reached : beyond this are irregular hills of an
olivine- basalt, which weathers into rounded elevations. Behind
and above is a line of flat-topped hills, apparently the edge of a
sandstone-plateau, which I was unable to visit. Farther north
runs a second escarpment, the Serra dos Parecis.
V. Devonian Rocks.
6. Chapada Sandstones.3
These sandstones appear to extend over the whole of the great
plateau of Matto Grosso, although in some places covered by later
beds. They have a slight dip towards the north. On the south,
near Cuyaba, they terminate in a lofty escarpment nearly 600
metres (1950 feet) above the undulating slate-plain. The lower half
of the escarpment-face consists of a steep slope, composed of the
highly-inclined slates. Above are vertical cliffs of red sandstone,
conglomeratic below, which higher up again pass into another slope.
The cliffs are undercut by the disintegration of the slates, which yield
much more readily than the other rocks to the action of eroding
agents. Large masses of the sandstone appear to break off from
time to time, owing to the removal of their support. As has been
remarked by Chandless (#), from the edge of the plateau the wide
slate-plain looks like a sea, and the escarpment, with its inlets
and promontories, has a curious resemblance to a coast-line. It is
1 Abore this point the Paraguay is an insignificant stream, it cannot be nari-
gated in large canoes, and according to some authors is improperly called the
Paraguay, (5) toI. i. pp. 107, 121.
1 Sandstones with the same characters and probably of the same age are
found on cither side of the valley of the Rio Sao Franoisoo, where they form
chapada* like that near Guy aba, (9) pp. 32, 310, (13) p. 7. Similar sandstones
also occur in Sao Paulo and the other Southern Brazilian States, (11) p. 254,
(13) p. 8, as well as in the Chiquitoa (see infra, p. «G).
Digitized by Google
96
DR. J. W. EVANS OW THK
[Feb. 1894,
not, however, necessary to have recourse to marine action for au
explanation of the present configuration of the country.
The sandstones are of recent appearance and comparatively little
consolidated, so that it is easy to understand why they were origin-
ally considered as being of Tertiary age. Red and white shales
are found interstratified with them.
The Chapada Sandstones may extend as far west as Beira on the
Rio Guapore, at which locality similar sandstones were observed
by A. d'Orbigny dipping south-east at an angle of 12° to 15°, (/)
p. 203, a dip that is unknown elsewhere in these beds.
I am informed by Mr. C. H. Ward that the isolated hill known as
Monro Grande, near Sao Antonio, on the Rio Cuyaba, a short
distance below Cuyaba, is an outlier of the Chapada Sandstones.
Mr. Herbert H. Smith, who, as I have stated, spent two years
in making zoological collections on the Chapada, found some
fossiliferous sandstone in the bed of the Corrego dos Morrinhos,
4 miles north-east of Sant' Anna da Chapada : 1 this occurs
near the summit of the Chapada Sandstones. According to
Mr. Derby's description, (8) pp. 73-88, the fossils are in an imper-
fect condition, and only a few are specifically determinable. The
following genera were identified : — Lingula, Discina% Strophodonta,
Tropidoleptm, Vitulina, Rhynchonella, Spirifer, Notothyris (?),
CentronfUa (?), Bellerophon, TentaculiUs, and Styliola. Mr. Derby
adds, " The specific characters, as far as they can be made out, show
close relationship, if not perfect identity, with the fossils of Erere
on the Amazonas, and with those of the Hamilton or Middle
Devonian Group of New York."
That author's paper contains an interesting discussion as to the
relations between the rocks of Matto Grosso and those of the rest
of Brazil. It also deals with the hilly region in Eastern Bolivia
called the Chiquitos. This, Mr. Derby considers, belongs rather to
the Brazilian highlands than to the Andes, (8) pp. 71-73, a view
which I can confirm. In reading A. d'Orbigny's account of the
Cbiquitos (7) pp. 183-199, 1 recognized the chief types of rock that
I had seen in Matto Grosso. They seem from his map and descrip-
tion to consist of a group of hills running east-south-east and west-
north-west, due to an anticlinal axis lying in that direction, but
rising towards tho west-north-west, where gneiss comes to the
surface in the centre, Hanked by the Cuyaba Slates which form the
centre of the anticlinal in the east-south-east. Outside these, but
with a distinctly smaller dip, are found the Corumba Limestone
(sometimes similar to that which occurs at Coimbra) and the Rizama
Sandstone.3 Above are the Chapada Sandstones, patches of which
lie unconformably and almost horizontally on the denuded anti-
clinal of older rocks. The Cuyaba Slates he calls Silurian, tho lime-
stone and Rizama Sandstone Devonian, and the Chapada Sandstones
1 In the short time at my disposal in the Chapada I was unable to see this
fossiliferous bed.
a Sandstone also occurs at the base of the limestone.
Digitized by Google
Vol. 50.]
GEOLO'.r OF MATTO G ROSSO.
97
Carboniferous; and he compares these different deposits with the
strata of the younger elevation of the Andes, in which later earth-
movements have produced the same consolidation and modification
as the earlier disturbances in the Brazilian region had done Ion*
before in its more ancient sedimentary deposits. A few isolated
exposures of Rizama Sandstone appear to occur in tho alluvium
north and west of the Chiquitos ; see (7) pp. 184, 197, and 200-201.
It may be suggested that the llizama Sandstone and Matto
Shales (unknown elsewhere in Brazil) are perhaps portions of the
Chapada Sandstones and accompanying Bbales, which have been
faulted down to their present position, outside and below the
Chapada escarpment. I have come to the contrary conclusion, for
the following reasons : — (a) The Chapada Sandstones are undis-
turbed and almost horizontal, within a comparatively short distance
of tho region where the llizama Sandstone and Matto Shales have
been affected by considerable earth-movemeuts. (6) Theso latter
rocks do not resemble the sandstones and shales of the Chapada.
The difference seems too great to be accounted for as the effect of
alteration, due to pressure accompanying disturbances, (c) In the
Chiquitos it seems clear, from A. d'Orbigny's account, that repre-
sentatives both of the Itizama and Chapada Sandstones are found,
and that tho latter are unconformable to the former.
The question can only be absolutely settled either by fossil
evidonce, or by following the Kizama Sandstone and Matto Shales to
the north-east, and ascertaining whether they flatten out into the
Chapada Sandstones, or — a more probable supposition — are covered
unconformably by them.
VI. — 7. Carboniferous (?)
Argillaceous shales with fossil ferns occur at Miranda on the
river of the same name, one of the eastern tributaries of the Para-
guay.1 These, Mr. Derby thinks, are probably of Carboniferous
age and correspond to fossil-bearing Carboniferous beds east of the
Parana', (8) pp. 60-67. Ho also thinks that rocks of the same ago
will ultimately be found on the Chapada plateau ; see (8) p. 61.
8. Trias (?)
Above the shales is fonnd, cast of Miranda, a horizontally-bedded
sandstone with eruptive basalt-like rocks.1 Mr. Derby believes this
to be identical with a similar sandstone exposed east of the Parana,
in which immense dykes and intercalations of augitc-porphyrito
occur, a sandstone which is regarded provisionally as Triassic ; see (8)
pp. 65-67.
1 This information was obtained in the course of a surrey of a proposed
railway from Curitiba, on one of the western tributaries of the Paraguay, to
Miranda, see (4)-
Q.J.G. S. No. 197. h
98 DR. J. W. EVANS ON THE [Feb. 1894,
9. Cretaceous (?)
Sandstone of the Tabolciros.1
According to Mr. Herbert II. Smith, (8) p. 03, this formation rests
on the Chapada Sandstone nnd is perfectly horizontal. It has yielded
vertebrate remains, among which Mr. Derby recognized a fragment
of a turtle's carapace and a vertebra of another reptile. Mr. Derby
says '* it is possible, though not very probable," that these beds may
prove to be identical with the sandstone with augite-porphyrito
already referred to as possibly Triassic. lie prefers, nevertheless,
to class them with the Cretaceous beds in Eastern Brazil, (8) p. (iS.
It may be remarked that on the Funis, one of the southern tribu-
taries of the Amazonas, and on its tributary the Aquiry, Upper
Cretaceous beds with remains of turtle and Afosataurus have been
found : see (tf) p. 404.2
VII. — 10. Quaternary.
High-level Surface-deposits.
In the neighbourhood of Cuyaba and elsewhere, the Cuyaba Slates
are frequently covered with a thick ferruginous deposit, consisting
largely of pebbles of vein-quartz. The ferric oxide cement is
abundant, and scoriaceous aggregates of the same material also occur.
More or less laminated deposits of iron oxide arc found on the
Chapada, sometimes in such quantity as to render the soil unfit for
vegetation. Ferric oxide is also widely distributed between the
hills at Kizama and the river Paraguay, but I did not notice it
to any large extent on the Matto Shales. It is found in the neigh-
bourhood of the basaltic rocks at Tapirapuam.3 Where these
ferruginous deposits occur, there also goitre and cretinism prevail.
The rivers are usually highly charged with iron, the rock washed
by them being often coated with a black deposit of iron oxide.
At Barra dos Bugres, high-level gravels occur in the hills some
20 metres (05 feet) above the Paraguay. The pebbles are exactly
similar to those found in the present river-bed.
1 Tabofeiros nre flat-topped bills.
a 1 Genera) Co^to dc Mnpnlliiies speaks of the occurrence of fossil woods on
the same tableland,' (cV) p. ti.'i. I fouud on the Chapada a fragment of ferru-
ginous material full of elongate cavities ; it certainly has the appearance of
wood, but wa« probably formed inorganically by the deposition of iron oxide.
Angiosperm wood occurs fossil near Coimbra, op. rit. p. (V4.
3 These ferruginous deposits are known in Brazil as canga. Mr. Derby
suggested in a letter to me that they were identical with the laterite of ludia.
This is», to a large extent, true ; but both terms are loosely employed.
Vol. 50.]
GEOLOGY OF MATTO OR0S80.
99
Alluvial Deposits.
The lowland plains and swamps arc composed entirely of alluvium,
though penetrated here and there by elevations of the older rocks.
The rivers bring down from the hills a vast amount of detrital
material, especially in flood-time. When a stream overflows its
bauks, the luxuriant vegetation on tho margin catches up and
entangles most of the matter held in suspension, so that a strip
adjoining the river is raised higher than the ground farther away.
In some localities remote from the courso of the princii>al rivers
permanent lakes of considerable area occur. In the time of high
water, which lasts for about six months in tho year, these lakes
appear to be merged in the extensive sheets of water (xaraes or
pantanae*) 1 which unite the courses of the Paraguay and of its
tributaries the Sao Lourenco, the Cuyaba, and others, and cover
almost all the alluvial plains. These facts point to the former
existence of a great lake or lakes (comparable to those of Equatorial
Africa or North America) which have been subsequently filled up
by alluvium.3
The alluvial deposits are in some places cut into by tho rivers,
and sections are tbus afforded. These occasionally contain thick
shell-bauds of a largo Ampullaria, apparently identical with one
that now inhabits the adjoining swamps.
VIII. Unclassified Itocxs.
At Urucum, near Corumba*, I found, overlying the ancient igneous
rocks and probably also the Corumba Limestone, deposits almost
entirely composed of oxides of iron and manganese. They form a
hill some 600 metres (l!».3«J feet) high, and "> or G kilometres (\\ or 3.J
miles) long. Somo of the neighbouring hills appear to bo of similar
composition, although it is said that they do not contain so much
manganese. Tho strata form a gentle synclinal. They seem to bo
fragments of former more extensive deposits (probably lacustrine),
and to owe their preservation to tho accumulation at this point —
the centre of a synclinal-— of the above-mentioned oxides, which
have proved more durable than the rest of the deposits.3
These rocks appear to bo younger than the Coruinba Limestone,
but are probably older than the Chapada Sandstones, for they have
suffered more from earth-movements. They may, perhaps, be a
local phase of the Matto Shales.
Massive siliceous iron ore, with geodes lined with quartz, occurs
near Coimbra, but I have not seen it in place.
1 [Perhaps here xarae* = Charcot, and pantanaes = panfatiof.—Vn.]
2 A similar process, on a much smaller scale, is now going on in the district of
the Norfolk Broad*. p. 353.
3 From the description given me at Uacurisal (a locality on the Paraguay
already referred to) of the rocks in the hills near Gahyba, farther nortu, it
Beetna not improbable that they may be similar to those at Urucum.
100
I>R. J. W. BVANS ON THE
[Feb. 1894,
IX. Igneous Rocks
I have already referred to the ancient igneous rocks of Corumba.
Von den Steinen found a granitic zone on the Xingu, 10° lat. S.,
"which may, perhaps, be of similar antiquity, (6) p. 133.
I met with an interesting augitc-syeuite at the Pao d'Assucar.
This, as its name implies, is a sugar-loaf shaped eminence on the
eastern bank of the Paraguay, about 21° 25' lat. S. It is one of a
group of hills rising out of the alluvial plain on either side of the
river.1 The rock contains orthoclaso somewhat altered, a little
plagioclasc, brownish-green hornblende, green augite, biotite, abun-
dant spheno (in fairly large crystals visible to the naked eye), and
apatite. As is sometimes the case in augite-syenites, the biotite may
often be seen surrounding the augite. The sphene is occasionally
formed round the hornblende as a nucleus.
Mr. Orville A. Derby, to whom I sent a fragment of this rock,
tells me that it closely resembles certain augite-syenites associated
with the nepheline (elaDolite)-syenites of Eastern Brazil, which he
has described, (15) p. 457, (16) p. 31 1, and (17) p. 251. I could not
detect elax>lite in thin sections of the rock, though it shows some
gelatinization on treatment with acid ; possibly there may be some
too small to be recognizable, or such small particles as onco existed
may have passed into some alteration-product. A nephelino-basalt
is reported from Paraguay at no great distance to the south, (14)
p. 247.
About 6 kilometres (3^ miles) south of the Pao d'Assucar is another
exposure of somewhat similar rock. This is much altered, with
secondary quartz ; plagioclase-felspar is predominant.
Mr. Derby has shown that the eheolito and augite-syenites of
Eastern Brazil are either late Carboniferous or post-Carboniferous.
The Pao d'Assucar rock will prove to be of the same age, if, as is
believed, it is a distant representative of this important petro-
graphical province of ncpheline-bearing rocks, which extends in the
opposite direction as far as the island of Sao Fernando da Noronha.
If, as seems likely, the basalt-like rocks of South-eastern Matto
Grosso aro identical with the widespread augite-porphyrites on the
other side of the Parana, they will be at least post-Carboniferous,
and probably of still later age.
The Tapirapuam rock is a rather coarse basalt, approaching a
dolerite. It contained abundant olivine, now altered into serpen-
tine and ferric oxide. Many of the felspars are ophitically included
in the larger augites. Most, hoto-ever, occur among granular augite,
or embedded in opaque material consisting largely of magnetite,
ilmenite, and leucoxene. There is no evidence of the age of this
1 The 'closing of the hills' upon the river at this place has suggested the
name, Fecho dos Monroe.
Vol.50.] GKOLOGT OP MATTO 0 ROSSO. \-' 101
rock, except that it is probably younger than the Matto Shales. I
had, unfortunately, no opportunity of determining whether it
occurred as a dyke or as the outcrop of an intrusive or intcrst-ratified
rock. In connexion with this basalt, Mr. Derby writes to me-: —
" Dykes, often of considerable size, of similar rocks are common" in
the Devonian and Carboniferous regions of the Amazonas and* of
Sao Paulo and Parana, as well as in the regions characterized by
the older rocks."
X. Historical Summary.
It may not be out of place here to briefly detail the succession of
conditions indicated by the geological structure of Matto Grosso
and the surrounding regions.
At a remoto j>eriod the materials now forming the Cnyabu Slates
were deposited over an extended area. In some places we havo
indications of the neighbourhood of land, consisting mainly of the,
even then, ancient crystalline rocks, which had already assumed the
characters that they now possess. Then came a period of great
earth-movements resulting in the folding, cleavage, upheaval, and
denudation of the slates. Subsequently, after depression had
occurred, the Corumba and Arara Limestones were widely deposited
on the crystalline rocks and upturned edges of the Cuyaba Slates.
Thenceforward there is progress to continental conditions. The
Rizama Sandstones and Matto Shales were deposited in successively
diminished areas, perhaps in freshwater basins.1 A second series
of movements (which had probably commenced at the close of the
deposition of the limestones) now moulded all the then existing
rocks into the continental mass that still forms the framework of
the Brazilian highlands. As none of these rocks yield fossils, we
can say nothing concerning the period when these events took place.
In Silurian times we find the sea covering the region west of Brazil,
where the Andes were subsequently uplifted, and also occupying the
Amazonas depression between the large islands now represented by
tiuiana and Central Brazil : see (JO) p. 1G0. In the Devonian period
general depression prevailed, during which extensive deposits were
laid down on the denuded surface of the old rocks. The depression
continued to some extent during the Carboniferous period. Tho
land then again rose, and since that time land conditions have
mainly prevailed. The sandstones of the Taboleiros and similar
rocks in other parts of Brazil seem to be local freshwater deposits ;
it is only on the sea-border that marine Secondary strata are
found. From tho Devonian period to the present time the horizon-
tally of the rocks seems to have been (except at a few points on
the margin of the continental massif) almost entirely undisturbed ;
1 The Matto Shales especially have the appearance of being of freshwater
102 DR. J. W. EVANS ON THE [Feb. 1 894,
and this' So* spite of the fact that, in the adjoining: region to the
westward, the comparatively recent elevation of the Andes has
been, to com pan ied by earth-movements of the greatest magnitude,
involving rocks of all ages.
; t\fis interesting to compare the geology of South America with
that of Southern Asia. There also enormous foldings have taken
••place in connexion with the elevation of a great mountain-chain in
# Ute geological times on the margin of an ancient land region, that
|Tias since remote ages remained practically undisturbed, except by
the repeated intrusion and eruption of igneous rocks. This region
in, of course, peninsular India, which geologically presents many
points of resemblance to Brazil. Indeed, most of the formations of
the two countries may (to coin a new but self-explanatory phrase)
be considered 4 tectonically homotaxial,' 1 or structurally equivalent,
to each other. Thus the 4 Metaraorphic ' corresponds to the ancient
crystalline rocks of Brazil. The 4 Transition ' represents the Cuyaba
Slates ; while the Vindhyan represents the Corumbu and Arara
Limestones and the Bizama Sandstone. The later Brazilian rocks
present points of resemblance to tho Gondwana group. It is
doubtful whether the rocks I have compared are in any case con-
temporaneous with one another — in fact, their ages may be widely
different ; but they have taken a similar part in the building-up of
the present land.
XI. Economic Products.
Gold has mainly been worked in the ferruginous conglomeratic
deposits overlying the Cuyabri Slates. These deposits have, through
a wide area, been completely turned over in tho search for the
precious metal. They are now neglected, although a few streams,
such as the Coxipo, arc occasionally worked. Most of the quart/.-
veins that penetrate the slates are not very auriferous, but I was told
that some reefs gavo good results. Gold is said also to be found
in the Chapada Sandstones, especially where there have been well-
marked breaks in the deposition.2
Diamonds. — Theso are found in deposits practically identical with
the alluvial workings in other parts of Brazil. They are chiefly
obtained from the valleys of two tributaries of the Paraguay, the
Kio Diamantino and the ltio Sant' Anna, aud the tributaries of the
1 [Two formations (in different couutries of similar geological structure) will
therefore be ' tectonically homotaxial,' when they come into existence at the
snine stage in the development of that structure, although they may not be
identical in actual age or fossil contents. — January, 181M.]
a In a watercourse on the Chapada, north of Sant' Anna da Chapada, I
found a small fragment of rock, which was stated by a negro who accompanied
me to be a specimen of the rock from which gold and diamonds are obtained.
In colour it is greenish-grey, weathering to yellowish-red. A great part of its
volume is made up of cavities, in shape and size like the grains of very fine
oolite. Most of the cavities are partly filled with crystalline quartz, and some
Vol. 50.]
GEOLOGY OF MATTO GROSSO.
103
latter. I have not visited the workings, which have to a largo
extent been discontinued since the abolition of slavery, as the work
is very unhealthy. The following details of the deposits aro sum-
marized from Costelnau, (J), 1*« Partie, vol. ii. pp.
4. Black argillaceous earth.
3. Gorgiiho. Small sandstone and quartz-pebbles cemented by
yellow clay.
2. Catealho. Larger pebbles without cement.
1. Bed argillaceous shales (probably Matto Shales).
In >~o. 2 are found, in addition to the constituents of No. 3, a
black or mottled quartz, a tine hone-like sandstone (probably derived
from the Kizama Sandstone), a violet sandstone, and diamonds. The
three former are regarded as indicators of diamonds. I found
similar pebbles in the Paraguay and its tributaries at and above
Barra dos Bugres, but saw no diamonds.' Castelnau states that
sandstones occur in the vicinity of the workings ; from these he
supposes the diamonds to have been originally derived.
Iron occurs in abundance, especially at Urucum.
Manganese is also found at I ruciim, whero it occurs in thick
deposits, which appear as a band of black cliffa halfway up the
mountain.
Copper (on the Rio Jauru), lead, and other metals are stated to
occur, (o) vol. i. p. 148.
In conclusion, I may mention that specimens and thin sections
from the principal localities which I visited aro deposited at the
British Museum (Natural History), South Kensington.
EXPLANATION OF PLATE VIII.
Geological Map of a Portion of South-eastern Matto Ore* no.
Xo'e. — The alluTial region shown in the map is a vast stretch of swampy low-
land, which is under water during great part of the year. For ' Livra-
menta' read • Livramcnto.' The position of Arara is on the limestone-
outcrop south of the Rio Ciripuru, and west of Livramcnto.
entirely so. The matrix is ferruginous and highly magnetic. An analysis by
Mr. G*. T. Holloway gave the following results :—
Per cent. ^
Silica D5-D70
Iron 2 690 corresponding to 1 „„1M
Magnetite ) J ,1U
Alumina «4:J3 y = lOOGoV.
Lime >4fiO
Magnesia *10"2
Manganese traces
Phosphoric acid traces )
Mr. Derby tells me that it resembles a weathered specimen of a pyritiferous
quartx-veinstone from MinaaGeraes. The pyrites appears to have been removed,
and additional silica deposited in the cavities left. He thinks that such a rock
may be auriferous, bat is not likely to contain diamonds.
1 A small crystal of topaz with rounded edge* was found there.
104
THE GEOLOGY OF MATTO OROSSO.
[Feb. 1894
Discussion.
The President pointed out that it would be wrong to judge this
paper by the ordinary standard. It might be described as a record
of the results of a geological reconnaissance in a comparatively un-
known country.
Mr. Spencer Moore, fellow-traveller with Dr. Evans in Matto
Grosso, gave a brief sketch of the fortunes of tho recent expedition
to that province. In the course of his remarks, Mr. Moore dwelt
on the difficulties met with ; difficulties so great that it was matter
for congratulation that Dr. Evans had been able to make out so
much of the structure of the districts visited.
Mr. H. Uauerhan and Mr. It. D. Oldham also spoke.
Digitized by Google
Quart. Journ. Qeol. Soc. Vol. L. PI. VIII.
Digitized by Google
5d by Google
105
J.
Jth,
u»r>
107
117
1<W
iblo
lian
but
the
iay,
and
lesy
the
fact
iral
igh
n is
hat
ies,
ted
•per
has
W.
een
and
I as
the
3 tO
?rly
s.
the
iuct
Digitized by Google
Digitized by Google
Vol. 50.] THE GEO LOOT OF BATHURST (*EW 80UTH WALES).
105
9. The Geoloot of Bathurst (New South Wales). By W. J.
Clusirs Ross, Esq., B.Sc., F.G.S. (Read November 8tb,
1303.)
Contents.
I. Introduction
II. Previous Work on the Subject
III. Physiography of the District
IV. Detailed Geology of the District
1. The Ceutral Area.
2. The Age of the Granite.
3. The Silurian Rocks.
4. The DeTonian Rocks.
5. Rooks newer than the Devonian.
6. The Later Tertiary Rocks.
V. Summary
Map and Section
I. Introduction.
Bathurst may be regarded as the centre of a district of considerable
geological importance, not alone as an isolated area in the Australian
colonies, which might be considered of merely local interest, but
because of its relationship to other areas. The solution of the
problems connected with its stratigraphy and petrography may,
therefore, contribute in no small degree to decide the age and
relative positious of many of the older rocks of New South Wales,
and enable us to correlate them with thoso of Victoria, on the
one side, and Queensland, on the other.
The late Rev. W. B. Clarke, F.R.S., long ago pointed out the fact
that all the older stratified rocks of Eastern Australia have a general
north-and-south strike, which can be traced from Victoria, through
New South Wales, to Queensland. This importaut generalization is
the key to much of Australian geology. When we ask, however, what
is known of the relationship of the rocks of the various colonies,
or even of different parts of the same colony, it must be admitted
that much still remains to be done.
In Victoria, it is true, rocks belonging to the Lower and Upper
Silurian have been recognized, and a thick series in Gippsland has
been classed as Lower, Middle, and Upper Devonian by Mr. A. W.
Howitt, F.G.S. In New South Wales the distinction between
Silurian and Devonian rocks has not been so clearly made out, and
over a large area the strata have been provisionally classified as
Siluro-Devoninn. Moreover, while there is uncertainty as to the
base of the Devonian system, there is also a good deal of doubt as to
its upper limit ; aud it has been suggested that mauy rocks formerly
classed as Devonian should be placed in the Lower Carboniferous.
Both Silurian and Devonian rocks are well developed in the
neighbourhood of Bathurst, where they form two very distinct
series, and as many of them are similar in character and fossil
Q. J. G. S. No. 198. 1
Page
. 105
. im
. \m
. 107
117
108, 10'J
106
MR. W. J. CLUSIES ROSS OX THE
[May 1894,
contents to those found elsewhere, a clear knowledge of the strati-
graphy of the district will enable one to classify the beds in other
parts of the colony, by establishing a distinction between those
belonging properly to the Silurian and those which are Devonian ;
and, further, to separate the latter from the Carboniferous. Under
these circumstances it is thought that a short account of the
geology of the Bathurst district may be of interest, not only to
Australian geologists, but to those who reside in other parts of the
world.
II. Previous Work on the Subject.
Very little has been done, or at any rate published, in reference
to Bathurst geology. In the writings of the Itev. W. B. Clarke
and others there are a few scattered notices. The late Mr. C. S.
Wilkinson, F.G.S., also alluded to it,1 and the same gentleman
carefully surveyed the country around Hydal, about 28 miles east
of Bathurst, and published a geological map and section of that
area.2 The work is well done and is very interesting, but unfortu-
nately no detailed account of the country seems to have been
written. In 1891 the Rev. J. M. Curran read a paper before the
Linnean Society of New South Wales, which he subsequently
published in pamphlet form.3 The paper mainly treats of the
petrography of the Bathurst rocks, although the stratigraphy of
the district is also dealt with to some extent. Apart from these
papers, and one or two which the present writer has contributed to
the Australasian Association for the Advancement of Science, nothing,
so far as he knows, has been published on the subject.
III. Physiography op the District.
Bathurst, a city of about 10,000 inhabitants, is situated 140 miles
west of Sydney, N.S.W., at a height of about 2100 feet above sea-
level. It is nearly in the centre of what are known as the Bathurst
Plains, a tract of undulating country surrounded by hills, which
rise to a height of 1000 to 2000 feet above the city. The Plains are
about 20 miles across from cast to west, and rather less from north
to south. The Macquarie river runs by the city and is formed by
the confluence of two streams — the Fish and Campbell rivers, which
unite to form the Macquarie about 6 miles above Bathurst. The
river is fed by a few creeks, one of which, the Vale Creek, skirts
the south side of the town and is of moderate size. The Macquarie
has a long course, flowing past the towns of Wellington and Dubbo,
to the north-west of Bathurst, and, ultimately, its waters form part
of the Darling system, and find their way to the Indian Ocean by
the Murray. Near Bathurst the river flows in a wide and deep
1 'Notes on Die Geology of New South Wale*/ Sydney, 1882, pp. 30 andG2.
2 Annual Report of the Department of Miuee for 1877, Sydney, 1878.
3 4 A Contribution to the Geology and Petrography of Bathurst, New South
Wales,' Proc. Linn. Soc. N.S.W. ser. 2. vol. yL pp. 173-234, & pis. xiY.-xviii.;
(*p. cops, published by Angus and Robertson, Sydney, 1691.
Vol 50.] GEOLOGY OF BATHURST (NEW 80UTH WALES),
107
channel, and. in time of flood is a fine stream. For the greater
part of the year, however, it only fills a small part of its bed. The
hills to the east are draiued mainly by the Wimburndale Creek,
which has a course of considerable length, and enters the Macquarie
a long way below Bathnrst. Near tho centre of the Plains, and
about 2 miles south-west of the city, are the Bald Hills, about
050 feet high, capped by a mass of basalt, 200 feet thick ; beneath
this is a layer of drift-gravel, which in places has been cemented
into a compact conglomerate. There aro also several terraces of
gravel, capping the lower hills and running roughly parallel to
the course of the river.
The Bathurst Plains form an extensive granite area, estimated at
450 square miles, while the hills, which rise at an average distance
of 10 miles from tho city, aro formed of metamorphic rocks. The
granite can be followed on the surface, however, for a much greater
distance around the valley of the Fish River and its tributaries.
The metamorphic rocks consist partly of highly altered rocks, such
as crystalline marbles, mica- and hornblende-schists ; partly of less
altered varieties, such as massive slates and silky schists, with, in
places, beds of limestone containing many fossils. Thoy are probably
all Silurian, but east of Bathurst they are backed by a bold escarp-
ment of Devonian rocks, consisting mainly of quartzites and sand-
stones. These attain a height of 4000 feet above sea-level, but
appear to be absent from the north, south, and west of Bathurst.
Mr. Curran states that the Devonian is overlain by Carboniferous
beds, but no rocks of that age are known to the writer as occurring
around Bathurst. (See Map and Section, pp. 108, 109.)
IV. Detailed Geology of the District.
1. The Central Area.
The granite over the greater part of the country is much decayed
near the surface, owing to the decomposition of its felspar. It
often appears compact enough where exposed on the banks of creeks
and in road-cuttings, but crumbles down at once when touched with
the hammer. In places, however, the granite is hard and compact,
and consists of light-grey felspar, quartz, black mica, and very often
hornblende, with spheno and apatite as accessory minerals. It is
mostly rather coarse-grained, with, in some localities, large crystals
of pale pink orthoclase, porphyritically developed.
At the Waterworks, Bathurst, small veins of calcite and prehnite
occur, developed along the joint-planes of the solid granite. When
examined microscopically, most sections show a good deal of plagio*
clastic felspar, probably oligoclase, so that tho rock might be called
a granitite, and affinities are suggested with the quartz-mica-diorites
of Gippsland, Victoria, described by Mr. Howitt. Some of the
large crystals of orthoclase show interesting instances of zones of
growth around the outlines of the crystals, and also a cross-hatched
structure suggestive of microcline.
7>/«.£&Aiwf Co St.
Note,— Ham only geological map of New South Wales, as a whole, ret pub-
lished is that which accompanies Mr. Wilkinson's 1 Notes on the Geology of
New South Wales.' It is based on the original map compiled by the Rev. W. B.
Clarke, F.R.S., and is on a scale of about JJO miles to 1 inch, ot course much too
small to display detailed geology. On it the limits of the Silurian and
Devonian rocks are certainly not drawn correctly for the neighbourhood of
RatbursL
The accompanying sketch-map has been drawn up by the writer from his
own observations, and, although on a small scale, is yet, it is believed, suffi-
ciently clear to enable the geology of the district, which is comparatively
simple, to be understood. The rone of rocks highly altered by oontact-meta-
morphism was symbolized in the original sketch by a thick line drawn round
the junction of the Silurian and the granite, but this has been unintentionally
omitted by the draughtsman who recopied the map. For 'Nap Reef read
' Napoleon Reef;' for ' Olanmure' read ' Glanmire.'
[Since this paper was written, a new geological map ha." been issued by the
Department of Mines, N.S.W. It is on a scale of about 15 miles to the inch,
and is in all respect* a great improvement on the old one.]
Digitized by Google
Digitized by Google
110
MR. W. J. CLUNIES ROSS OX THE
[May 1894,
Scattered through the mass of the rock are patches of fine-grained
granite, largely composed of black mica. The rock is traversed,
moreover, by veins of a granite differing considerably from that
which surrounds them. These veins are common in the decomposed
granite, but have themselves apparently undergone very little decay.
Some are very fine-grained, while others are excessively coarse, and
these often occur very close together. All are alike made up of
quartz and pink orthoclase, often coated with scales of nearly white
mica.
Near the boundary of the granitic area there is a change in the
rock, and it approaches in character that found in the veins, the
biotite and hornblende disappearing or becoming scarce, the former
being replaced by muscovite, and the felspar being of a reddish
tint.
At certain localities in the district- several other varieties of
granite occur. Thus, at Locksley, about 15 miles east of Bathurst,
there is a fine porphyritic granite, very similar in appearance to the
Shap granite of Westmoreland, and at Sarana, still farther east,
there is a rock composed of white felspar and quartz, with little
mica, approaching a pegmatite in appearance. The granite near
the boundary of the metamorphic area affords good examples of
granophyric or micro-pegmatitic structure.
2. The Age of the Granite.
One can hardly speak with much confidence as to the age of the
granite. It is clearly newer thau the Silurian rocks, since it sends
veins into them, and there is a broad zone of rocks altered by
contact-metamorphism surrounding the granite. Whether it is
newer, as a whole, than the Devonian rocks is doubtful. The latter
are certainly foldod to some extent, but not nearly so much as the
Silurian. They are traversed in places by what appear to be
intrusive dykes of felstone, highly siliceous, and often porphyritic.
In some cases they rest directly on the granite, and at Rydal the
late C. S. Wilkinson described them as being altered at the
contact. Near Lithgow the granite is overlain by rocks of Carboni-
ferous and Permian age.
On the whole, the writer is inclined to think that the granite is
not all of the same age. The first intrusion may have taken place
subsequent to the deposition of the Silurian, but prior to that of the
Devonian rooks, and there may have been a second intrusion,
accompanied by further tilting and crumpling of the Silurian and
disturbance of the Devonian strata, which sent veins of felstone
into thorn, and converted many of the sandstones into quartzite.
The different character of the granite at the centre and near the
boundary of the area seems to support this view, although it is not
easy to draw any boundary-line between the two types ; but this
may be owing to the fact that most of the country is covered with
soil and under cultivation, so that good exposures are only attain-
able at places some distance apart. The series of veins which
Vol. 50.] GEO LOOT OF BATOTTB8T (5EW 80T7TH WALES). Ill
traverses the central mass of granite is probably connected with the
second intrusion.
In the New England district, Northern New South Wales,
Prof. T. W. E. David, F.G.S., recognizes granitic rocks of at least
two ages.1 In Victoria most of the typical granites are classed
as newer than the Silurian, but older than the Upper Palaeozoic
strata.3
A fairly typical specimen of the biotite-granite, from the Water-
works, Bathurst, gave on analysis 68*5 per cent, of silica; its specific
gravity was 2*75 to 2*79. Granite close to the junction with schist
yielded 73*5 per cent, of silica. Specific gravity 2*59 to 2*62.
3. The Silurian Rocks.
Very good exposures of the junction of the granite with the
overlying rocks occur at many localities around Bathurst, and one
is at onco struck by the similarity of the contact-rocks when
examined at places as much as 20 miles apart. The metamorphic
rocks at the contact differ to some extent among themselves, as to
fineness of grain and in other ways, but they are nearly all of the
same type — namely, a kind of hornblende-schist, although they can
hardly be called typical schists. Most of them are tolerably coarse-
grained, but some are so fine that they appear like quart zite or
tine-grained felstone. Under the microscope they are seen to consist
largely of quartz, with a good deal of a green mineral, strongly
dichroic, but not usually occurring as distinct crystals or showing
cleavage-lines. It is probably altered hornblendo, the rock having
evidently undergone much change from its original condition.
Perhaps the best name for the contact-rock is horn f els, as suggested
by Mr. Curran.
An average specimen of this rock, from the Wimburndale Creek,
near Peel, gave 66 per cent, of silica; granito from the same
locality yielded 73*5 per cent. The specific gravity of the hornfels
varies from 2*75 to 3. A collection of the contact-rocks was shown
by the writer to Mr. A. W. Howitt, F.G.S., who remarked that
he could match them all from Gippsland, Victoria.
In all cases the junction is sharp and well defined, there being
no instance known to the writer in which there is any indication
of a gradual passage from the granite to the hornfels, such as
would suggest that the granite had resulted from the extreme
metamorphism of the overlying rocks. There is often a creek
running roughly parallel to the junction, so that the line of contact
may be followed for a considerable distance at several localities.
The line is an irregular one and winds about in a curious manner :
the granite often sending small veins into the metamorphic rock,
so that there can be no possibility of a faulted junction. The
1 • The Geology of the Vegetable Creek Tin-Mining Field,* by T. W. Edge-
vorth David, F&.8., Department of Mines, N.S.W., 1887.
a ' Victoria— Geology and Physical Geography,' bv Reginald A F. Murray,
Melbourne, 1887, p. 24.
112
UK. W. J. CLUNIE8 ROSS ON THE
[May 1894,
writer possesses a microscopic section taken exactly across the
junction, and the contrast between the granite, with felspar but
nothing approaching hornblende, and the hornfels, with no felspar
but much of the green mineral, is very striking.
Outside the altered contact-zone the character of the rocks varies
considerably. South of Bathurst there is an area of highly altered
rocks. These are mainly micaceous and hornblendic schists, which
in places contain felspar and become gneissic in character. Inter-
bedded with them are crystalline limestones, pure white or with
bluish markings, mostly rather coarse-grained, but often well suited
for ornamental purposes as marbles. These rocks are generally
nearly vertical, and often much crumpled. In places they contain
copper ore, which has been worked to some extent at a locality
known as Cow Flat. North of Bathurst similar rocks occur, but
they are, as a rule, less altered, many huving the character of massive
slates rather than schists.
The metamorphic rocks north and south of Bathurst are so much
altered that it is difficult to form an idea as to their age. Cambrian
rocks are known to occur in Tasmania and South Australia ; while
Lower Silurian strata are extensively developed in Western Victoria,
and, in the eastern part of that colony, some of the Silurian rocks
of Gippsland have been provisionally referred to the same age,
although it is admitted that the determination is somewhat doubt-
ful.1 As the strike of the beds there is north and south, they
might bo expected to pass into New South Wales, but hitherto no
beds of Lower Silurian age have been definitely recognized in this
colony. Some of the Bathurst rocks may eventually be proved
to be of that age.
East and west of the town the rocks are less altered than on the
north and south. At several places the hornfels is succeeded by
spotted schists, very much like some of the rocks near the'Skiddaw
granite of Cumberland, but the chiastolite-slate, so well known
there, has not yet been found in this district.
The spotted rock passes into silky schists, and these into massive
slaty rocks, seldom showing distinct cleavage. No fossils have yet
been found in the slates, although some of them look promising
and may repay further search. At Limekilns, about 16 miles
north-east of Bathurst, there is, however, a bed of limestone,
apparently interstratified with the slate, and this contains many
fossils in good preservation. It is a bluish limestone, about 50 feet
thick, the strike being N.N.E. and the dip W.N.W., about 30°,
but variable. Some of the layers are largely made up of encrinite-
stems, but others consist mainly of corals. Of these Mr. Curran
mentions Siromatopora siriatella, Favositts fibrosa, and Petraiay sp. ;
also a new species of Phillipsastraa, which has been described by
Air. K. Etheridge, Jun., and named P. Currant.2 There are several
other corals, including, probably, Favositcs gothlandica, and also
brachiopoda. The latter have not been systematically described,
1 • Victoria — Geology and Physical Geography/ R. A. F. Murray, p. 42.
3 Record* Geol. Surv. N.S.W.* vol. ii. pt. iy. (i892) p. ltiti, pi. xL
Digitized by Google
Vol. 50.] GEOLOGY OP BATHUB8T (NEW SOUTH WALES).
113
but the writer has found indications of a Pentamerus. probably
P. Knightii. This fossil, P. Kniyhtii, is also found in other parts
of the colony ; as at tho celebrated Jenolan Caves, which are
situated about 50 miles E.8.E. of Bathurst ; at the Tarrangobilly
Caves, in the extreme south of the colony ; about Yass, and
elsewhere. It is, of course, a very well-known Upper Silurian
fossil in Europe, and its occurrence in New South Wales goes far
to stamp the beds in which it is found as of approximately the same
age. Mr. K. Etheridge, Jun., believes that it characterizes a
particular horizon in this colony.1 Should this prove to be the
case, the fossil will be very useful, by enabling us to correlate the
various beds of limestone, together with the beds interstratified
with them, at a largo number of places. The other fossils at
Limekilns lead one to the same conclusion, and the limestone has
therefore been generally recognized as of Upper Silurian age.
At Hockley, about 20 miles south of Bathurst, there is a blue
limestone much resembling that at Limekilns, but composed almost
entirely of eucrinite-stems. It will very likely prove to be of the
same ago.
The Silurian strata on the east side of Bathurst generally dip
eastward, although occasionally the dip changes to west owing to
folding. On the western side the dip is westerly, so that there
appears to have been a great anticlinal fold over what are now
the Bathurst Plains, which has been completely denuded away
from that area. One would expect in this case to find a repetition
on the west of the beds which occur on the east ; but, owing to the
great similarity of tho different beds of slaty rocks, it is extremely
difficult to recognize outcrops of the same bed at a distance from
one another. The limestones would be more likely to be recog-
nizable, but unfortunately these appear to exist rather in lenticular
masses than in extensive beds, so that it is doubtful whether
much assistance will be obtained from them.
Quartz-reefs are very common in the Silurian rocks around
Bathurst. Many of them are auriferous, but few contain enough
gold to repay working, although some of the richest alluvial
workings in the colony have been situated not very far awav, as
at Sofala, about 25 miles N., and Hill End, 30 miles N.N.E.,
where reef-mining has also been extensivoly carried on. During
the last year or two successful attempts to extend some of the old
workings have been made ; among other places, at the Napoleon
Beef, about 10 miles east of Bathurst.
Veins, other than qnartz, are not uncommon. They mostly, like
the quart z-reefs, follow the general strike of the country rocks and
appear to be interbedded v* ith them ; and, as they have evidently
undergone much alteration, it is often difficult to say whether they
are intrusive, or have resulted from local changes in some of the
sedimentary beds. One such vein, at Glanmire, 10 miles east, is
seen under the microscopo to have a matrix of quartz, crowded with
1 'On the Pentameridrc of New South Wale*,' Records Geol. Surv. K.S.W.
vol. iii. pt. ii. 181)2.
114
MR. W. J. CLUXIKS ROSS OX TIIE
[May 1894,
minute crystals of, probably, epidote, surrounding large green
crystals. The specific gravity of the rock is 3*04.
The strike of the Silurian strata varies from N.N.W. to N.N.E.,
sometimes changing within a short distance.
4. The Devonian Rocks.
The passage from Silurian to Devonian beds is not easy to
observe near Bathurst, and an actual section showing the junction
has not yet been met with by the writer. Nevertheless, there is a
distinct change observable, both in the character of the rocks and
the nature of the country, when passing from one series of rocks to
the other ; and an alteration in the flora may also bo noted, the
Silurians being richer in species of plants than the Devonians.
On travelling eastward from Bathurst, one passes over low hills
of granite and then reaches the Silurian rocks, which rise into
higher hills with a comparatively gentle slope, followed by a fall
in the ground to a creek, where one is again at about the level of
the city. Once more the ground rises, still with a gentle slope,
and the ground is covered with downwash from the hills beyond,
so that good exposures of the rocks are not common. Where seen,
however, they are still slaty or schistose rocks of the Silurian
type. Then the slope becomes much steeper, rising to a height of
about 1000 feet, and, on working up the face of the escarpment, one
immediately notices that the slates have entirely disappeared, the
rocks consisting mostly of massive beds of quartzite and grit, with
intrusive sheets of felstono. The summit of the escarpment is in
some places a thick bed of conglomerate formed of well-rolled
pebbles of, mostly, hardened slate, but mixed with others of more
siliceous rocks. The conglomerate does not extend very far if
followed along the strike, and elsewhere the highest beds are of
grit. The strata dip eastward into the hill at an angle varying
from 10° to 30°. By following the course of a creek which runs
nearly east and west, some very fair sections may be observed, and
the beds are found to be undulating, occasionally dipping west ; the
whole appearance of the rocks contrasts markedly with that of the
Silurian strata, to which there can be little doubt that they are
unconformable.
The grit-beds, interstratified with the quartzites, are largely
made up of the casts of brachiopoda, notably Spirifer disjunctus and
lihynchonella jrfeurodon, so that they are often called the • Bra-
chiopod Sandstones.' There are, however, a few corals and other
fossils as well, including a Lepidodendron, which is of interest,
since there has been some doubt as to whether it occurred in these
rocks or not.
Among the fossils enumerated by the late C. S. Wilkinson,
F.G.S., from the Devonian beds of Rydal is Lepulodendron nolhum,
linger.1 Dr. Feistmantel, in describing the older fossil plants of the
1 * Notes on the Geology of New South Wales,' p. 42.
Vol. 50.] GEOLOGY OP BATH U EST (NEW SOUTH WA»>
115
Australasian colonics,1 also mentions it as occurring in various parts
of New South Wales aod Queensland. In Victoria a species of
Lepidodendron occurs which has boen described by Prof. M'Coy as
L. austrah? It is now contended by Mr. R. Etheridge, Jun., and
others that the true L. nothum does not occur in the colonies at all,
but that the specimens so described should be classed as L. australe.
The question is ably discussed by Mr. Etheridge in a paper
published in 1891.* The rocks in Victoria containing L. awstrah
have been provisionally classed as Lower Carboniferous, and
Mr. Etheridge suggested in his paper that the beds in New
South Wales in which the same fossil occurred should be classed
as newer than Devonian. The question of the occurrence, or
otherwise, of the fossil in the Brachiopod Sandstones, generally
admitted to be Devonian, became therefore of some importance.
It has been taken up by Prof. David, of Sydney University, and
Mr. E. F. Pittraan, A.R.S.M., Government Geologist, N.S.W., who
worked together at Mr. Wilkinson's old section at Rydal ; and by
the writer, working at Glanmire, near Bathurst. At both localities
specimens of Lepidodendron have been found associated with the
Devonian brachiopoda ; one of thoso obtained by the writer being
actually attached to a cast of Spinfer dhjunctus. Some other
vegetable remains were found at the same place, but not sufficiently
definite for classification. It appears therefore to be proved that
lepidodendron is Devonian in New South Wales, unless it can be
shown that the Brachiopod Sandstones are Carboniferous.
With the exception of the Devonian rocks above described, there
are apparently no rocks of that age within a radius of at least
20 miles, but the Brachiopod Sandstones are well known in many
other parts of the colony. Nearly all the Devonian fossils occur
as casts, but better-preserved specimens are found in the more
shalj beds.
5. Rocks newer than the Devonian.
As already mentioned, the Devonian rocks are in places traversed
by what appear to be dykes of felstone similar to some of those
occurring in the Silurian. They are probably not much younger
than the rocks which they traverse.
With the exception of these, no rocks younger than the Devonian
are knowu in the district, until wo come to the Tertiary drifts and
the superincumbent basalt. Near Rydal, and at Lithgow, still
farther east, the Devonian beds are overlain by Carboniferous rocks.
About Lithgow one of the principal coal-fields of the colony is
1 ' Geological and Patoontological Relations of the Coal- and Plant-bearing
Beds of Paleozoic and Meeozoic Agn in Eastern Australia and Tasmania,' by
Ottokar Feistmantel, M.D., Mem. Geol. Sunr. N.S.W., 1890, Department of
Mine*, Sydney.
8 Prodr. Pal. Vict. 1874, dec. i. pi. ix.
* ' Lepidodendron australe, SA *Coy— Its Synonyms and Range in Eastern
Australia.* Records Geol. SurT. N.S.W. vol. ii. pt. iii. pp. 119-133.
MR. W. J. CLCNIES ROSS ON THE
[May 1894,
situated. Tho Coal Measures appear to belong to the upper series
and are probably of Permian age, but beneath them is a series
of sandstones and shales, considered to belong to the Lower Coal
Measures, or Upper Marine series, of Xew South Wales, and to be
of Middle or Upper Carboniferous age. These were found by
Mr. Wilkinson to be quite unconformable to the Devonian bods.
The exact limits of the Carboniferous rocks are scarcely known ;
but they do not appear to approach Bathurst, and it is doubtful
whether they, or any Mesozoic beds, ever existed in the district.
6. The Later Tertiary Rocks.
In this neighbourhood there are several distinct beds of gravel.
The highest, and no doubt the oldest, is situated west of the town,
near the top of the Bald Hills. It is composed of well-rounded
pebbles, made up almost entirely of quartz, which have evidently
been rolled a considerable distance, since none of them are large ;
and it carries a little gold, but is not rich.
The basalt which caps the hills is about 200 feet thick. It is
a moderately coarse-grained rock, containing numerous crystals of
augite and olivine in a matrix which, under the microscope, is seen
to be mainly made up of lath-shaped crystals of plagioclase-felspar.
Microscopic sections present a remarkably fresh appearance, and
sometimes show flow-structure very well. Some specimens show
numerous white spots of calcite. When freshly broken the rock is
of a bluish-black colour, and it is often columnar, the columns being
about 12 to 18 inches in diameter, rather irregular in shape, from
four- to seven-sided, five sides being perhaps the moot usual. The
columns show the usual transverso jointing, with occasionally the
ball-and-socket arrangement at the ends, but this is not common.
The rock makes first-rate road-metal. Mr. Curran 1 quotes an
analysis by Mr. Miugaye, of the Mines Department, giving: —
Silica 44*67 per cent., alumina 21*38, lime 10*24, magnosia 9o8,
ferrous and ferric oxides 8*81. The writer's determination of the
silica agrees fairly well with this. The specific gravity of several
specimens gave a mean of 3*2.
Mr. Wilkinson was of opinion that the basalt came from Swatch-
field, about 40 miles S.E. of Bathurst, near the head of the Fish
and Campbell rivers. A specimen of basalt from Obcron, which
is in that direction, is finer-grained than the Bathurst rock, but
presents similar characters uuder the microscope; this confirms
Mr. W'ilkinson's opinion. There are, however, some indications that
the basalt may have come from a different direction. The flow can
be followed along the top of the Bald Hills for about 4 miles, to near
the village of Berth, but there ceases abruptly, and there is no
basalt known to the writer in the direction of Swatchfield for at
least 20 miles. The trend of the flow is also rather away from
that direction. At Blayney, 20 miles S.W., and Orange, 35 miles
1 ' Geology and Petrography of Bathurst,* Proc. Linn. Soc. N.S.W., ser 2,
toI. ri. (lt#l) p. 227 ; eep. cops. p. 57.
Vol. 50.] GEOLOGY OF BATHTR3T (*EW SOUTH WALES).
117
▼est, there is plenty of basalt, but this is of an entirely different cha-
racter from the Bathurst rock, so that the latter is not likely to have
come from either place. At a hill called Fitzgerald's Mount, about
14 miles west, the writer has found a basalt much resembling
Bathurst basalt in microscopic characters ; but further examination
is necessary before one can speak with confidence on the subject of
its identity or otherwise.
As to the ago of the drift under the basalt little can be said.
Diligent search has so far failed to reveal a single fossil, except
some pieces of silicified wood, in that or any other Bathurst drift.
It is about 400 feet above the level of the Macquarie River, and
at the time it was deposited there was probably high ground
over much of the present Bathurst Plains, so that it must have
taken a long time to denude away so great a thickness of rock.
The granite which underlies the drift is, as already mentioned,
much decayed to a considerable depth from the surface, and this
decayed granite is sometimes worn away very quickly, deep creeks
being formed in the course of a few years.
It is, indeed, a characteristic of the country around Bathurst to
find creeks from 10 to 20 feet deep, with vertical sides, and termi-
nating abruptly at the head of the channel. These sometimes form
a miniature river-system : there being a central channel with
numerous tributaries, all running in canons on a small scale.
The creeks are usually dry, except after heavy rain ; but if in
the past the rainfall was much greater than it is now, from 20
to 30 inches a year, the work of denudation may have gone on
very rapidly.
The freshness of the basalt docs not indicate a great age, and
probably the oldest gravels are not older than the Pliocene period.
The gravels next in age to that on the Bald Hills are at a much
lower level, but of similar character, being formed of small quartz-
pebbles, with beds of sand, and showing much false bedding. The
later gravels, however, which form terraces roughly parallel to the
Macquarie, are of different character, being much coarser and con-
taining large pebbles, mainly of Devonian grits and felstones;
they are very similar to the present river-gravel.
V. Summary.
The probable geological history of Bathurst, so far as at present
known, may bo thus briefly summarized : — The oldest sedimentary
rocks of the district are Silurian. There was evidently an upheaval
some time after the close of the Silurian period and before the
Carboniferous : there may have been more than one such move-
ment. The Silurian strata may possibly have been folded before the
granite was erupted, as it is suggested those of Victoria were ; but
this is uncertain. In any case, the granite produced a zone of con-
tact^metamorphism, while almost the whole of the Silurians may
be considered to be examples of 4 regional metamorphism * ; but
the agents producing changes in the rocks were most active south
118
MR. W. J. CUJ>'IES ROSS OX TUB
[May 1894,
of what is now Bathurst, and least so to the east, where the lime-
stone is very little altered. The granite intrusion probably produced
an anticlinal, and raised the area above the sea. After a time
there was most likely a subsidence, but not at first a very great one,
and the central area may not have been submerged, since the
Devonian rocks, consisting of conglomerates, sandstones, and shelly
limestones, with plant-remains, were probably deposited in a com-
paratively shallow sea. There must, however, have been a very
great subsidence before the end of the period if, as Mr. Wilkinson
states, the Devonian rocks are 10,000 feet thick at Kydal. Near
Bathurst they have not been measured, but they do not appear to
be so thick as that. They may have been reduced by denudation,
but very possibly wero originally thicker near Rydal than where
they abut against the Silurian uplift in the Bathurst area.
It is uncertain whether the Devonian rocks belong to tho
Lower, Middle, or Upper division of the system, but at the close
of the period there must have been a loog interval during which
both Silurian and Devonian Btrata were greatly denuded, and the
granite exposed in places. This probably included the time when
Lower Carboniferous rocks were beiDg deposited in other parts
of the colony. Then the Upper Carboniferous and Permian rocks
were formed in the Lithgow district, but it is doubtful whether they
ever extended to Bathurst.
What was the condition of the Bathurst area during the Meso-
zoic and early Tertiary periods there is no evidence to show. Just
east of Lithgow, the Hawkesbury Sandstone (probably Triaasic)
occurs, of great thickness, and this very possibly once extended
much nearer Bathurst than it does now. There is, however,
a great gap in the geological history of the district until we come
to late Tertiary times. We then find evidence that the streams
ran over granite beds in much the same courses as they do now,
but the country as a whole was probably a good deal more elevated
than it is at present. Volcanoes burst out somewhero in the
district, and thcro may have been several centres of eruption.
Floods of lava were sent down the channels of the streams, sealing
up the drifts under thick layers of basalt.
Since the volcanoes became extinct, subaerial denudation has
gone on steadily. All the high ground around the streams has been
swept away, the materials going to increase the great deposits of
drift-earth far to the west. Most of the basalt has also gone,
only tho outliers on tho Bald Hills, and on a few other small hills
in the neighbourhood, remaining to indicate the course of the old
river-channel, now become a hill. As the stream or streams shifted
their courso and cut their channels deeper, they left terraces of
gravel to mark the successive heights at which they flowed.
There is a popular tradition that the Bathurst Plains were
formerly covered by a lake, but there does not seem to be any
evidence in support of this. No doubt, in wet years, much of tho
low ground around the channel of the Macquarie, and between the
low hills, may have been covered by water for some time. By tho
Vol. 50.] GEOLOGY OF BATHURST (NEW SOUTH WALEs).
119
general testimony of old inhabitants, the channel of the river has
become both wider and deeper during the last twenty or thirty
years, its capacity for carrying off flood-waters has thereby been
increased, and extensive floods have become rarer. The channel
mav once have been very shallow, so that wide stretches of country
would be temporarily covered with water, giving it the appearance
of a lake, and thus accounting for the tradition.
Discussion.
The President said that the paper dealt with a comparatively
unknown district, and it appeared to contain many important facts.
He thought that the Author had not clearly connected the mcta-
morphic with the Upper Silurian rocks. There was evidently a great
hiatus between the Pentamerus A'mVjr/tfu-limestone and the overlying,
so-called Devonian.
The Rev. H. H. Win wood and Mr. J. E. Marr also spoke.
120
HR. H. KYXASTON ON THE
[May 1894,
10. On the Stratioraphical, Lithological, and Pal^oktological
Features of the Gosau Beds of the Gosau District, in tlie
Austrian Salzkammergut. By Herbert Kynaston, Esq., B.A.,
Scholar of King's College, Cambridge. (Communicated by J. E.
Marr, Esq., M.A., F.R.S., Sec.G.S. Head December 20th,
1893.)
Contexts.
Page
I. Introduction 120
§1. Prefatory Remarks 120
§2. Bibliography 121
§ 3. Situation and Physicnl Aspect* of the Gosau Valley 123
II. Distribution of the Beds: Stratigraphy of the Gosau District, and
Comparison with other Areas 123
III. Paleontology of the Gosau Beds 134
]V. Geological Horizon of the Gosau Beds 137
V. Physical History of the Gosau Beds 147
VI. Summary 14»
Map 126
I. Introduction.
§ 1. Prefatory Remark*.
During the latter part of the summer of 1892, I was enabled by
means of a grant from the Worts Fund (Cambridge University) to
do some geological work in the Eastern Alps. My observations
during the seven weeks or so that I spent on tho Continent were
confined to the Upper Triassic and Upper Cretaceous rocks of the
neighbourhood of Aussee, Altaussee, Hallstatt, and Gosau, iu the
Austrian Salzkammergut, and more especially to the Cretaceous
rocks of Gosau ; and it is the remarkable formation here developed
that I propose to deal with in this paper.
I am aware that the subject of the Gosau Beds is by no means a
new one, and that many eminent stratigraphies and palaeontologists,
-whose researches have brought forth a copious literature and much
discussion, have been before me in the same field. With the
exception, however, of the remarkable researches of Murchison and
Hedgwick, little, if any, detailed work has been done on these beds
by English geologists. Furthermore, although the formation at
Gosau and other places in the Eastern Alps has been known for a
long time, yet ita isolated position, peculiar stratigraphical relations,
and unique fauna have always been subjects of much discussion
amongst European geologists, and the question of the exact geo-
logical horizon of the beds and their palaeontological relations cannot
even yet be said to have been definitely settled.
It is proposed, therefore, in the following pages to give a summary
of the results of the principal previous investigations on the strati-
graphy and palaeontology of the Gosau Beds, to give a full account
of my own observations and subsequent palaeontological work, to
Vol. 50.3
GOSAU BEDS OF THE OOSAU DISTRICT,
121
eompare my observations with the views of other workers, to
discuss from the results that I have obtained the geological horizon
of the beds, and to endeavour to point out their probable English
equivalents.
§2. Bibliography.
In dealing with the literature of the Gosau Beds, I have not
referred to accounts published before the classic memoir of Sedgwick
and Murchison. These illustrious pioneers of geology visited the
Gosau district in the year 1829, and the results of their investigations
appeared in a series of papers on the Eastern Alps, which were read
before the Geological Society of London at various meetings during
the years 1829, 1830, and 1831, and these were finally rearranged
and published as a separate memoir, entitled * On the Structure of
the Eastern Alps,' in the ' Transactions ' of the Society (2nd ser.
vol. iii. pt. ii.) in 1832. Before the year 1829 the Gosau district had
been described in a more or less geoeral manner by Keferstein (' Geo-
logic von Teutschland,' vol. v. 1827) and Lill von Lilienbaoh. The
memoir, however, of Sedgwick and Murchison was the first account
of any importance. Their views were immediately opposed by Ami
Boue, who had studied the Gosau Beds near Wiener Neustadt in
1822. These he had taken for Jurassic, but later he classed them
as Lower Greensand, in opposition to the views of Murchison and
Sedgwick, who maintained that they represented passage-beds
between the uppermost Cretaceous and the lowermost Tertiary
deposits ; in fact their whole memoir was a gallant attempt to bridge
over with the Gosau Beds the great gap between the Secondary and
Tertiary systems of Europe.
Even in 1843 we find Klipstein upholding the Tertiary age of
these beds, and, while recognising the Cretaceous character of the
fossils which they contain, he accounted for their presence by
supposing that they were simply derived from an older Cretaceous
formation, which had been entirely destroyed during the deposition
of the Gosau Beds. Then followed various papers and memoirs
by Czjzek, Peters, Zekeli, Reuss, Fr. von Haoer, Stoliozka, Zittel, and
others. I append a list of all the references to, and descriptions of,
the Gosau Beds and their organic remains, that I have been able to
find, as having appeared since the year 1832. The rich series of
organic remains from Gosau and other places have been described by
Zekeli, Reuss, Stoliczka, Zittel, Fr. von Hauer, and H. G. 8eeley, and
the descriptions of some of these authors have enabled me to
identify a large number of the fossils which I collected from these
beds.
1832. Sedgwick k Mracmsoi*.— • On the Structure of the Eastern Alps.'
Trans. Geol. 80c. 2nd eeriet, toI. iii. pi. ii. pp. 351 t& weqq.
1843. Klipstkin, Dr. A. vox.— * Beitrage sur geologiechen KenntiiiM der oat-
lichen Alpeo/ j>p. 23-24.
1849. MuRCHison, Sir R. I.— 'On the Geological Structure of the Alps. Apen-
nines, and Carpathian*,' Quart Journ. Geol. Soc. toI. t. p. 157.
Q. J.G.8. No. 198. *
122
ilR. H. KTXASTOK 05 THE
[May 1894,
1850. ton Haute. Fbabz. Bitter.—' Ueber die geogno*tischen Y*erbaltni«ee des
Nordabhanges der nordostlichen Alpen zwischen Wien und Salzburg.'
Jahrb. d. k. k geol. Beichtanst. vol. i. pp. 44-46.
1851. Czjzek, J.— Jahrb. d. k. k. geol. Reichsanst. vol. ii. p. 144.
[Describes the coal-bearing beds of Grunbacb.]
1852. Petebr, Dr. C. — 'Peitrag zur Kemuniss der Lagerungxverhaltniss* der
obcren Kreideschichten an einigen Local i tit ten der ostlicben Alpen.'
Abhandl. d. k. k. geol. Reiehaaust. rol. i. |>art i.
[Describes Gosau Beds at Zlam and Gamstbal.]
,, Zekeli, Dr. Fr. — ' Die Oasteropoden der Gosaugebilde.' Abbandl. d.
k. k. geol. Reichsanst. toI. i. part ii. pis. i.-xxiv.
1853. Rbcrs, Dr. A. E.— 4 Kritische Bemerkungen uber die von Herro Zekeli
bebchriehenen Oasteropoden der Gosnugebilde in den Ostalpen.'
Sitzungsber. d. kaiserl. Akad. Wieaensch. Wien. vol. xi. p. 882.
„ Reuss, Dr. A. E. — 'Ueber zwei neue Rudisten-8peciea aus den alpinen
Kreideecbichten der Gosau.' Sitzungsber. d. kaiserl. Akad. Wissensch.
Wien, vol. xi. p. 923.
1854. Rel'88. Dr. A. E. — 'Beitrage ziur Charakteristik der Kreideschirbten
in den Ostalpen.' Donkschrift. d. kaiserl. Akad. Wissensch. Wien,
vol. vii. p. 1 .
1856. PiciiLKR. — ' Zur Geognosie der nordostlichen Kalkalpen Tirols.' Jahrb.
d. k. k. geol. Reiehsanst. vol. vii. p. 735.
1858. vow Haueb, Fha*z, Bitter.— 4 Ueber die Cephalopoden der Gcoau-
scbichten.' Beitrage zur Palaont. v. Oesterrei' b. i pt. i. p. 7.
1859. Stoliczka, Dr. Feed. — ' Fieber cine der Kreideformation aDgehortge
Susswasserbildung in den nordostlichen Alpen.' Sitzungsber. d.
kaiserl. Akad. Wissensch. Wien. vol. xxxviii. p. 482.
18H1. Gum bel. — ' Geognostische Beschreibung d. Bayerischen Alpengebirges,'
pt. i. pp. 517 et ttqq.
1865. Stoliczka, Dr. Feed.—* Eine Revision der Gastropoden der Gotau-
schichten in den Ostalpen.* 8itzungsber. d. kaiserl. Akad. Wissensch.
Wien. vol. lii. pt. i. p. 104.
„ Zittel, Dr. K. A. vox. — ' Die Bivalven der Gosaugebilde in den nord-
ostlichen Alpen, I. Diroyaria.' Denkscbrift. d. kaiserl. Akad. Wis-
sensch. Wien, vol. xxiv. pt. ii. p. 105.
1866. Zittel, Dr. K. A. von. — ' Die Bivalven der Gosaugebilde in den nord-
iWlichen Alpen, II. Monomyaria.' Denkschrift. d. kaiserl. Akad.
Wissensch. Wien, vol. xxv. pt. ii. p. 77.
„ von Haver, Frakz, Ritter.— * Neue Cephalopoden aus den Gosaugebilden
der Alpen.' Sitzungsber. d. k. Akad. Wissensch, Wien, vol. liii. p. 300.
1874. Redtrnrachbb, Dr. A.—' Ueber die Lagerungsverbaltnisse der Gosau-
gebilde in der Gams bei Hieflau.* Jahrb. d. k. k. geoL, Reiehsanst.
vol. xxiv. part i. pp. 1-6.
1875. Tbibolet, Dr. Maurice pb. — Neues Jahrb. pp. 52, 53.
[New locality for Gosau Beds in Transylvania.]
1878. vob Haver, Franz, Ritter.—* Die Geologie der oaterr.-ungar. Monarcbie,'
pp. 516 et *tqq.
1879. Credner.— 'Traite de Geologie.' pp. 559. 565. (French Tranal.)
1881. Serley. H. G.— ' The Reptile Fauna of the Gosau Formation. With a
Note on the Geological Horizon of the Fossils at Neue Welt, west of
Wiener Neustadt, bv Prof. Ed. Suess.' Quart. Joum. GeoL Soc.
vol. xxxvii. pp. 620-707.
1882. Toccas. — ' Synchronisme des rttages Turonien. 8erionien et Danien dans
le Nord et dnns le Midi de l'Europe.' Bull. Soc. Geol. France, ser. 3,
vol. x. p. 200.
1885. Gbikib, Sir ARrniBALn. — ' Textbook of Geology.' 2nd ed. p. 836.
de Larfarent, A. — 'Traite de Geologie.' 2nd ed. p. 1 118.
1888. pREwrwirn. J.—' Geology,' vol. ii. p. 307.
1891. Katskb, Dr. E.— ' Lehrbuch der geologischen Fonnationakunde,' p. 280.
Vol. 50.]
OOS1U BEDS OK THE OOSAU DISTRICT.
123
§ 3. Situation and Physical Aspects of the Gosau YalUy.
The Gosau Valley is situated in the south of Upper Austria, close
to the borders of Styria, and in the heart of the Salzkamtnergut.
It forms almost a complete semioircle to the west and south-west of
the Lake of Hallstatt.
The waters of the Gosau Bach have their origin in the glacier-fed
streams of the western slopes of the Dachstein, which rises to a height
of over 10,000 feet above the sea-level. These streams plunge into
the Hintercr Gosau See, a small lake about £ mile long, and thence
descend somewhat steeply to the Vorderer Gosau See, in a north-
westerly direction, receiving on their way the mountain-torrents of
the Donnerkogl. From the foot of this lake, which is about 1 mile
long and \ mile broad, the stream keeps a general northerly course,
sometimes trending slightly to the east, until it reaches Gosau
village, about 5 miles from the Vorderer See, when it gradually
sweeps round to the east, and maintains this courso down the narrow
gorge of tho Gosauzwang until it finally mingles with the waters of
Hallstatt Lake at Gosau Miihle.
The Gosauthal proper consists of that broad, open, cultivated,
portion in which the village of Gosau lies, and which extends
approximately from Gosau Schmidt on the south to Klaushof, a
couple of miles or so E.N.E. of Gosau village. The whole of this
valley thus forms one of the main lines of drainage on the northern
slopes of the Dachstein massif : another well-marked line of drainago
being formed by the Wald Bach, which flows E.N.E. from the
Hallstatt glacier.
It is not difficult to see that the physical characteristics of this
valley are due to its peculiar geological structure. Thus the steeper
and bolder portions, both in the neighbourhood of the Gosau lakes
and in the Gosauzwang, consist of hard, compact, crystalline lime-
stones, much folded and disturbed, belonging to the Upper Triassic
Dachsteinkalk and Wettersteinkalk, the latter of which constitutes
the jagged chain of peaks of the Donnerkogl, reminding one of the
dolomite mountains of the Tyrol ; while the former builds up the
greater part of the Dachstein group and most of the higher mountains
round the Lake of Hallstatt. But in that portion of the valley which
constitutes the Gosauthal proper there is a broad, more or less
basin-shaped, depression in the Alpine limestone. It is in this that
we find the considerably younger and less disturbed Gosau Beds ; and,
as one would expect, they consist of much softer material, chiefly thick
beds of marl, alternating with sandstones, shales, and conglomerates.
Hence the decreased height and gentler slope of the flanking moun-
tains, the broad pasture-lands and generally tamer aspect of the
valley.
»
II. Distribution of the Beds : Stratigraphy op the Gosau
District, and Comparison with other Areas.
The Gosau Beds, while they may be said to be typically developed
in the Gosau Valley, have on the whole a fairly extensive distribu-
e 2
MB. H. XYXABTOK ON THE
[May 1894,
tion in the Eastern Alps, and chiefly on the northern flanks of the
chain. They nearly always occur in basin-shaped or trouph-shaped
areas in the Alpine limestone, similar to that of which the Goaau-
thal may he taken as a fair type, or in small, narrow, high-lying
valleys, resemhling that of Zlam, near Anssee, in Styria. As
before mentioned, they generally flank the northern zone of Alpine
limestone (Kalkalpenzone), with, however, the oxception of the one
locality of Obersiegsdorf,1 south-east of the Chiem See in Bavaria ;
but they never encroach on the central axial portion of the chain.
Everywhere they occur in the form of isolated outliers, resting
unconformably on the older Alpine Trias, and they are nevor
associated with either younger or older Cretaceous beds, with one
exception, namely near liuhpolting 1 in Bavaria, west of Salzburg,
where they are exposed resting on beds of the age of the Gault.
The beds of the Gosauthal are not confined to that valley, but, con-
stituting as they do the whole of the hills on its western side, from
the Zwicsel Alp on the south to the southern slopes of the Kussberg
on the north, they are continued into the adjoining valley of Russ-
bach as far west as a mile or so south-west of Russbachsag, and
they also extend up the tributary valley of the Randoa Bach as far
as Neue Alp, between the Gamsfeld and the Hohe Platten. Farther
west they are again seen in the neighbourhood of Abtenau, at the
Untersberg, and at other places in the neighbourhood of Salzburg.
West of Salzburg the Gosau Beds occur at Urschlauer Achen,
near Ruhpolting, Obersiegsdorf, and other localities in the south of
Bavaria. In the Tyrol they have been described by Pichler a in the
Brandenberger Thai.
North of the Gosau Valley we find the Gosau Beds in the basin of
St. Wolfgang, which commences at St. Gilgen and extends as far as
Ischl; this locality has been described by Dr. A. E. Reuss.3
Probably one of the most important and best known localities for
the Gosau Beds is that of Neue Welt, near Wiener Neustadt, south
of Vienna, where they occur in a typical basin in the older Alpine
limestones, in the neighbourhood of the villages of Piesting, Griin-
bach, Dreistatten, and Muthiuannsdorf. The strata here exposed
have been well described by Sedgwick and Murchison,4 Cijzek,' and
Zittcl.' Other localities are the Gamslhal, near Hieflau, in Styria,
described by Peters7 and Redtenbacher,* and that of Zlam, near
Aussee (also in Styria), described by Peters,7 and more briefly by
Sedgwick and Murchison,4
More recently a new locality for the Gosau Beds has been de-
1 Zittel, Denkschrift. d. kaiserl. Akad. Wissensch. Wicn, vol. xxt. (1866)
p. 162.
3 Jahrb. d. k. k geol. Reichstanst. vol. Tii. (1856) p. 735.
9 'Beit rage sur Charakteristik der Kreideecbichten in dec Ostalpen,' Denk-
schrift. d. kaiaerl. Akad. Wiwenach. Wien, rol. rii. (1854) p. 1.
4 Trans. Oeol. Soc. eer. 2, roL iii. pt ii. (1832) p. 364.
8 Jahrb. d. k. k geol. Reichaanrt. toL ii. (1851) p. 144.
• Denkachrift, d. kaiserl Akad. WiMenech. Wien, vol. xxv. (1866) p. 160.
' Abhandl. d. k. k. geol. Reichsanst. vol. i. (1852) pt. i.
• Jahrb. d. k. k. geol Reichsanst vol. xxiv. (1874) pp. 1-6.
VoL 50.] GOSAU BEDS OF TBE 0O3AXF DISTRICT
125
scribed in Transylvania by Maurioo de Triboiet.1 That author
describes a collection of fossils from Monorostia, on the Maros,
which occur as impressions in a reddish ferruginous sandstone, and
from which 24 species of Gosau forms have been determined. Several
other localities for various beds of the same age are also known in
South-eastern Hungary, in Southern and Western Transylvania, etc. ; 51
but these, of course, do not come within the province of the Eastern
Alps.
Returning now to the Gosau Valley, we find that it is compara-
tively easy to establish the boundary-line between the Gosau Beds
and the older Triassic limestones, upon which they rest everywhere
with a marked unconformity. I do not know of any spot in the
Gosauthal or in the Russbachthal where this unconformable junction
is actually exposed to view, but everywhere the stratigraphical
evidences of it are too clear for one to mistake their significance.
As a rule the older Triassic limestones tower up above the younger
Gosau Beds as steep mountain-slopes or almost perpendicular
precipices, so that the actual boundary-line between the two is
almost always covered over by talus. In the Gosauthsl proper
we find the younger beds extending from noar Gosau Schmidt on
the south to the foot of the Barn Bach on the north. On the eastern
side of the valley they form the lower slopes of the Kessenberg and
part of its summit, while on the western side they constitute the
whole range of mountains from the Zwiosel Alp to the lower slopes
of tho Russberg and the Hoho Platten, the highest in the range
being the Horuspitze, about 5000 feet above sea-level. They are
continued westward into tho Russbachthal as far as Heugut, and
stretch up the tributary valley of the llandoa Bach on the north as
tar as Neue Alp. The total area occupied by the beds would probably
not average much less than 30 square miles.
The Map which is included in this section illustrates tho distri-
bution of the Gosau Beds in the Gosauthal and the Russbachthal. It
is based on the Austrian Ordnance Survey Map (Zone 15, Col. ix.
Ischl & Hallstatt — scale 1 : 75,000), on a copy of whioh I marked
in from my own observations the extent of the beds and the nature
of the principal strata in the different parts of the district. A
geologically-coloured map of this district was published with Reuss s
memoir on the Gosau Beds (Denkschrift. Akad. Wion, vol. vii. 1854),
but I had not seen this until my own was completed. My own map
will be seen to agree with Reuss's in the maiu, but to differ in several
smaller, though not unimportant points, chiefly with respect to the
boundary-line between the Gosau series and the older Alpine
limestones. (For Map, see p. 126.)
By far the best series of natural exposures of the beds are found
on the sides of the peculiar ravines or gullies (yraben), in which the
mountain-streams are confined, and which are so characteristic of
the district. Often, however, as in the lower part of the Wegsoheid-
1 Neues Jahrk 1875, pp. 52, 53. Noticed in Geol. Record for 1875, p. 104.
a Fr. von Hauer, • l5ie Geologic der osterr.-uugar. Monarchic,
pp. 534 and 536-538.
120
MR. H. KYNAST05 05 THE
[May 1894,
graben, scarcely anything can be seen of the actual beds in situ, the
steep sides of the ravine consisting of disintegrated shale and marl
in an almost soil-like condition, throughout which the various
characteristic fossils are loosely scattered, though generally merely
as casts or in a more or less fragmentary condition. This is usually
the case when the slope of the sides of the ravine is gentle enough
to allow of the disintegrated material of the rock resting upon them,
I
—
L1V1Y 1 1 .
ft,<»Vi»>rfiftwL-:-r-rt Bom SdtiU
. t*i i'i itf *i i1 '1 Vr-Vy-p
S Tnassie €r JurtutU Limattmts
- ^ CfH£titn*r*U Strut. \
I/iff nrilt. AcUrt»iellA &
A'eritura •timtitmti .
Fstunrint Btfls Gr
Foisiti/trmis Marls.
Vffrr Gesau Bfdt.
Satdi'cncs {•" Flags,
Ktd <5- Grty Marls.
If
r±± of the GOSAU BEDS in ±r
FCOSArTIIALAMlU'SSIIAfllTIlAL
Approximate Scale
4 Mites - 7 Inch.
:.
By Herkfrt Kyxjsto.v.
:. ' ; . '. r r 1 up
and with this are mingled soil and plants-remains from above,
boulders, pebbles, and innumerable shells of land-molluscs. Great
masses of soil and rock may sometimes slip down from the upper
part of the banks, bringing with them trees and shrubs, and in this
way a portion of the ravine may in process of time become inextri-
cably choked up by a confused mass of the trunks and branches of
dead fir-trees, masses of soil, boulders, and disintegrated marl, the
Tol. 50.]
GOSAU BHDS OF THE OOSAU DISTRICT.
V27
whole forming by no means a pleasing prospect from the point of
view of the stratigraphical geologist.
North and north-west of Gosau village there are a large number
of these ravines, no less than eight having been carved in the sides
of the mountain between the road going over the Gschutt Pass to
Abtenau and the eastern boundary of the Gosau Beds. Of these,
going from east to west, the principal are the ravines of Rirn Bach
(or Barengraben Ferbergraben, Kreuzgraben, Edelbachgraben,
and Wegscheidgraben. Along the lower portion of the Barn Bach
steep slopes and perpendicular faces of Triassic limestone (Dachstein-
kalk) come abruptly down for some distance along the eastern side.
Along the western side I did not find any rock in tilu, but the
steep and roughly-terraced banks consist of soil, gravel, and large
boulders, probably morainic material. Possibly, if time had allowed,
exposures of the basement conglomerate-aeries might have been
found higher up the ravine.
In the three next successive ravines to the west, including Ferber-
graben, nothing is seen except very coarse conglomerates. The
bedding is so massive that it is often extremely difficult to make out
the stratification. The dip, where seen, is in a general south-westerly
direction, and varies in inclination from about 30° to 50°. The
conglomerate consists chiefly of large pebbles, sometimes boulders
of about 1 foot in diameter, of different varieties of crystalline
limestone ; they are generally well-rounded, though more or less
angular, schistose-looking fragments sometimes occur. Quartz-pebbles
are not very common ; the matrix is calcareous, and generally very
hard and compact, of a greyish colour, or sometimes reddish from
the presence of iron oxide. This coarse conglomerate is found
almost right up to the head of the Ferbergraben, here and there
alternating with bands of reddish grit and sandstone. Near the bead
of the stream the conglomerate alternates with beds of bluish marl-
stone, sometimes containing a few badly-preserved fossils. Still
higher up the side of the hill, the beds appear to abut against a
steep wall of Dachsteinkalk running almost N.E. and S.W., and
forming the conspicuous scars of the Uohe Platten and the liussberg.
Passing westwards to the Kreuzgraben, we find at the foot of the
ravine, close to a chalet, similar conglomerates alternating with
soft reddish marls ; but farther up the gully only conglomerate is
exposed. Probably we have here the passage from the coarse con-
glomerate-system to that of the fossiliferous marls, so well exposed
in the ravines farther west. The conglomerate-system is certainly
more massively developed in this neighbourhood than in any other
part of the Gosauthal or the Russbachthal, and its thickness
probably amounts to nearly 300 feet.
In the Edclbachgraben, the next raviue of any importance to the
west, one is at once struck by the complete absence of conglomerate.
We find, however, a thick series of bluish-grey marls and shales,
with here and there a band of tough bluish-grey sandstone, dipping
1 Reuu, Denkschrift. d. kaiserl. Akad. Wiwenuch. Wien, vol. vii. (1864) p. 6.
128
MR. H. KTNASTOIf 05 THX
[May 1894,
at an angle of about 20° in a general 8.8. W. direction. There
marly and shuly beds may be followed some way up the ravine, and
are probably more than 100 feet in thickness at this locality. A
large number and variety of fossils characterize these beds, such, for
instance, as : Afontlivaltia rxtdis (E. & H.), Cyclolite* hemispkorrtca
(Lam.), Plimtula aspera (Sow.), Heithea quadricostata (Sow.), Car-
di urn productum (Sow.), Nerincea fiexuosa (Sow.), AmpuUina bulhi-
formis (Sow.), Turbo dtcoratu* (Zek.), Aporrhai* casta ta (Sow.),
Cerithium reticomm (Sow.), and many others.
A little farther west, at Schrickpalfen, on the sides of the hill, wo
find conglomerate overlain by Hippurite- and Coralline-limestones,
and these again by marls. Hippurite* comu-vaccinum and H. orga-
ntsam occur, and several reef- building species of corals. Above
the limestones we find marls similar to those of the Edelbachgrabcn,
and containing similar fossils. These marls again occur farther west
in the Wegscheidgraben, close to the road leading from Gosau village
over the Gschutt Pass to Abtenau.
Passing over into the Russbachthal, one finds the lower portion of
the Gosau Beds well exposed throughout the greater part of the
tributary valley of the Kandoa Bach, with a similar succession to
that already observed in the graben north of Gosau village. On the
slopes of the Traunwand, near the Alpenhiitte, wo find calcareous
conglomerate overlain by Hippurite-limestone, consisting of large
individuals of Hipp, comu-vaccinum, numerous corals, and a few
brachiopoda, while a little lower are calcareous marls, crowded with
Actceonetta conica, Cerithium Simonyi, Volvulina kevis, otc. Conspi-
cuous banks of Hippurite-limestone again occur above the Stockl-
waldgraben, close to a chalet, and are doubtless on the same horizon
as those on the Traunwand Alp.
A good section, showing beds low down in the fossiliferous series,
is exposed in the bed of a small stream entering the Itandoa Bach, a
short distance above the last-named locality of the Stocklwaldgraben.
Alternations of conglomerates, sandstones, shales, and marlstones
are seen, with many fossils in some of the marlstones, such as
Pinna cretacea (8ch\.)f Cypricardia testacea (Zitt.), Panojxm frequent
(Zitfc.), and Nerinara gracilis (Zek.). Sometimes blocks of marlstone
consisting almost entirely of Volvulina lawis may be extracted.
Actavnella giganUa (Sow.) and Nerincea Buchi (Kefct.) also occur,
and a few corals.
The Hippurite-limestone is of more or less local occurrence
and does not always crop out immediately above the basement-
conglomerate, although that is invariably its position whenever it
does occur ; so sometimes we may get the conglomerate-system pass-
ing gradually up into the marl-system without the intervention of
any limestones.
The Ne rintra -1 i m es t on e is well exposed in the bed of the stream a
short way below the Neue Alp. It occurs as a conspicuous mass of
compact grey limestone, about 6 feet in thickness, and containing
in places crowds of Nerivmi nobitis, usually arranged in bands.
Above this, we notice, a little farther on, bluish sandstones and marls ;
Digitized by Google
Vol. 50.]
G08AC BHDS OF THE O08AU DISTRICT,
129
these are probably part of the brackish-water or estuarine beds,
which on the east side of the stream at the Neue Alp have been
worked for coal. They consist for the most part of soft, pale
grey marl a with thin layers of a bituminous coal, and containing
brackish-water shells, such as Mclania granluatocincta (Stbl.) and
Tanaliu PichUri (Horn.), both of which are extremely common.
The gasteropoda from these beds have been described by Stoliczka,1
and a few lamellibranchs by Zittel.* They belong to a mixture
of land, freshwater, and murine forms, so that the beds are pro-
bably of brackish-water origin, and were most likely deposited in
an estuary.
The boundary-line of the Gosau Beds in this neighbourhood seems
to curve sharply round to the north of the Neue Alp, so that in this
valley we have a long tongue-like extension of these beds, gradually
tapering off towards the head of the stream.
On the south side of the Kui*»b;ichthal there are good exposures at
the Nef^ruben, a deep, tortuous ravine on the north-western slopes of
the Hornspitze. A thick series of dark grey marls, here and there
alternating with shales and sandstones, is exposed, with two bands
of limestone towards its upper portion containing BippuriUs and
numerous reef-building and other forms of corals. A larger and
more varied series of corals may be collected here than in auy other
locality in the Gosau district. The whole series of beds here
exposed probably amounts to almost 1000 feet in thickness; the
general dip is rather east of south, and the angle varies consider-
ably. The following are some of the commoner forms occurring
here : —
Lamki.libranchiata.
Ayathelia aspertlla (Reuse).
Trochotmrfia complanatH ( E. A H.). (Brotin).
Dipiocterium lunatum (Mich.). Hippurite* organisms.
Rhtpidugyra unduJata ( Keuaa). Plagioptycku* AguUhni (d'Orb/).
magnifica (Reum). Janira \Nctihea) quadrioovtatu
„ ratuwu (E. 4 il.j. (Sow.).
„ reticulata (E. A H.). Panop&a frtquens (Zift).
Nontlicaltia rudis (E. A H.). Cgpricardia tettavea (Zitt.).
Calamophyllia multicincta (,Reu«). Cardtum product urn (Sow.).
Hudncpkora atynaca (E. A 11.).
TkainMoserma, several »p. Oastbropoda.
Cyciolitcs macrodoma (Route). Volvulxna Ubvis (d'Orb.).
„ eihpt tea (Lam.). Ampultina (Natioa) bulbiformi*
„ hcmispfuertca (Lam.). (Sow.).
Natica li/rata (Sow.).
A/torrhai* costata (Sow.).
Ctritkium rtticwmm (Sow.), ete.
Returning to the western side of the Gosauthal, we find good ex-
posures of the fossiliferous marls in the Finstergraben, a small ravine
immediately south-west of Gosau village. The beds resemble those
ot the Edelbachgraben, already described, but are higher in the series,
1 8itztmgsber. d. kaieerl. Akad. Wiaaeneeh. Wien. toI. xxxviii. (1859) p. 482.
* Deiikaclirin. d. kaiterl. Akad. Wiseenech. Wien, vol. xxv. (1866) pi. ii. p. 77.
130
MR. H. KT.V ASTON ON* THE
[May 1894,
and, as they are traced up towards the upper part of the ravine, they
become more sandy, while the fossils gradually disappear. Thus the
upper slopes of the Bibereck, above the ravine, consist of tough bluish
sandstones, alternating with sandy micaceous shales aud Hags, and
containing scarcely any organic remains. In the lower part of the
Finstergraben CrauaUlla macrodonta (Sow.) and Cucullmi chiemi-
ensis (Giimb.) are very characteristic, besides the other commoner
forms ; also Aftorrhais (Alaria) costata (Sow.) and MalapUra
(Pteroctra*) tlaturi (Zek.).
Farther south-west a fairly deep grabm leads up to the Bibereck Alp,
and in this we find the unfossiliferous beds, seen above the Finster-
graben, well exposed. Alternations of shale with flaggy micaceous
beds and bands of tough bluish sandstone are frftquent, while the
only organic remains are obscure vegetable-fragments, and worm-
tracks on the surface of the flaggy and sandy beds. These beds are
evidently of a very shallow-water character, but when traced up on
to the Bibereck Alp and on to the upper slopes of the Hornspitze,
gradually a slightly deeper-water type of deposit is found to pre-
dominate, and the sandstones, flags, and sandy shales give place to
greyish, red, variegated, tine-grained, and tough marls. Just above
the Bibereck Alp this marl system is exposed in a fine cliff-section,
which must be at least 300 feet in height ; it forms another cliff just
below the top of the Hornspitze, on its eastern side, and is exposed
in numerous ravines and gullies in the hills between the Finster-
graben and the Zwiesel Alp.
On the eastern side of the valley the Gosau Beds occupy a much
smaller area than they do on the western side. The fossiliferous marls
are well exposed in the Hofergraben, almost immediately opposite
Gosau village. The succession here resembles on the whole that of
the Finstergraben, and is probably on the same horizon. Here also
the fossiliferous marls and shales gradually pass up into a series of
bluish-grey sandstones and sandv micaceous shales, with worm-
tracks and ripple-marks. Similar beds are also found in the various
small ravines, which cut into the sides of the hills between the
Hofergraben and Gosau Schmidt. Close to the top of the Ressenberg
thick beds of the bluish-grey sandstone predominate, and are
quarried at the Schleifsteinbriicho for whetstones and grind-
stones.1 Apparently the great system of grey and red marls of the
Hornspitze, the Hennarkogl, and the Zwiesel Alp is not present on
the eastern side of the valley, though the sandstoue-and-sandy shale
system, with worm-tracks and ripple-marks, is better developed on
this side, and possibly its upper portion may represent part of the
red-and-grey marl series.
We are now in a position to construct a complete classiftcatory
table of the Gosau series as exposed in the Gosauthal and the Russ-
1 Sedgwick and Murchison, Trans. Geol. 800. 2nd ser. toI. iii. pt. ii. (1832)
p. 3*8; Reuse, Denluchrift. d. kaieerl. Akad. Wiwenech. Wien, vol. vii. (1854)
pp. 27, 28.
Digitized by Google
Vol. 50.]
GOSAU BEDS OP THE GOSAU DISTRICT.
131
bachthal. We have traced the beds in ascending sequence from the
northern portion of the district to the southern, and have noted
their variations in lithological characters and the principal organic
remains characterizing the different series.
The average dip of the strata is south, varying from almost
horizontal up to an angle of about 50°. The beds of the ltussbachthal
are more disturbed than those of the Gosauthal. The total thickness
of the group probably does not fall far short of 3000 feet, the
Hornspitze, which is about the highest mountain Hanking the
western side of the valley, being a little over 2000 feet above tho
level of Gosau village, aud it consists chiefly of the massive upper
unfoasiliferou8 series.
Sedgwick and Murchison1 divided up the series into six principal
systems, as follows, in ascending order : —
1. Coarae conglomerate-system ; maximum thickness 200 to 300 feet.
2. Arenaceous limestone or calc-gnt, here and there in strong bands,
alternating with bed* of pebble* and great masses of marl ; very
fossiliferous. Thickness about 150 feet
3. A great system of blue marls, here and there with bands of indurated
marl, calc-grit, or sandstone, aud abounding in well-preeervcd organic
remains.
4. Alternations of marl*, sandy marls, and sandstones, with obscure traces
of plant-remains (beat exposed on the sides of the Re*aenberg).
5. Greenish, grey, micaceous, thin-bedded sandstone. Portions well ex-
posed near the top of the Retwenberg. Several hundred feet.
6. Red, ulaty, micaceous sandrttone, alternating with greenish and reddish
sandy marls. Partly on the same parallel with the preceding, and
partly higher. SOO'feeU
Reuss's classification 3 is as follows : —
11. Basement conglomerate.
2. Fosaihferous bluish-grey marls, interstratified with limestones
containing Hippuntes, Actaoncha, Merinaa, and corals, with
sandstones and conglomerates.
3. Grey and red, indurated, unfowiliferous marls, sometimes alter-
17 iter -I nating with sandstone and conglomerate.
4. Calcareous One-grained saudstoues, with grey micaceous marls;
unfossiliferoua.
Zittel also divides the Gosau Beds into four main divisions,3 in
ascending order, as follows : —
{Conglomerate and Hippuritenkalk with Hipp.
AeUvonellenkalk with gasteropoda.
Nerineenkalk.
2. Freshwater beds of the Neue Alp ; shales with coal.
3. Soft grey marls with corals, bivalves, gasteropoda, hippurites (H. or-
ganitans), and Caprina.
4. Grey and red, hard, unfostihferous marls, alternating with sandstones and
conglomerates, fine-grained sandstones, aud grey micaceous marls.
It will be noticed that both Sedgwick & Murchison and Beuss
supra cii. pp. 355-358.
p. sttpra cit. p. 35.
* Denksohrift. d. kaiserL Akad. Wis^ensch. Wien, toL xxt. (1866) pt. ii.
p. 173.
132
MR* H. KTITASTOX 05 THE
[May 1894,
omit any mention of the estuarine beds with coal at the Neue Alp,
while Zittel makes thorn constitute a separate division.
Sedgwick and Murchison completely mistook the position of the
lower Hippurite -limestone, regarding it as resting immediately
against the Triassic limestones, and belonging altogether to an older
series of Secondary deposits, but not to the Gosau Beds at all,
although they recognized two species of Hijtpuritts in their lower
fossiliferous series (No. 2). Zittel, on the other band, takes the correct
view of the posit ion of the t wo Hippurite- limestones, but hardly seems
to give due importance to the sandstone- and-saudy shale series, so
well developed on the Ressenberg, and he seems rather to confuse it
with the succeeding group of red and grey marls. It seems to me
that quite as much prominence should be given to each of these
two systems as to that of the fossiliferous marls, although, of course,
the latter are more important from a palteontologicol point of view.
Sedgwick and Murchison split up the fossiliferous marls into two
portions on palaeontological grounds (op. jam cit. p. 357). There is
certainly, however, no stratigraphical line of demarcation in the
series ; nor do subsequent investigations seem to have confirmed
the existence of so much distinction, pakeontologically, between the
upper and lower portions as those authors considered they had
grounds for establishing. Hence, it would seem more convenient
to retain the fossiliferous marly beds in one group.
Bearing in mind these considerations, and also the results of my
own observations, I have adopted the following classification of the
Gosau Beds of the Gosauthal and the BussbachthaL For the sake
of convenience we may divide them into a lower group, which is
extremely fossiliferous, and an upper group, which is almost entirely
devoid of organic remains.
The beds are arranged in ascending order : —
f a. Coarse conglomerate, sometimes alternating with grits,
sandstones, and marls (Ferbergraben, etc.).
^1.^ b. Limestone with Hipp, cornu-vaccmum (Traunwand, etc.).
i c. Do. ArtaonelUt coniea, etc. (Traunwand, etc.).
\jd. Do. Nerineta (Traunwand, Neue Alp).
2. Estuarine series of the Neue Alp.
3. Bluish-grey marls, with some limestone; Tery fossiliferous.
Hippu rites organisms, reef-building corals, Trvchosmilia,
CyclolUe*, Panoptea, Cypricardia, Janira, Cardntm,
CucuUaa, Crasaatella, etc Ampullina bulbij'ormu,
Cerithium, Aporrkais, Fiuus, Xrrineea, etc.
'4. Grey sandstones and flags, with some sandy shales, with
obscure plant-remains, worm -tracks, and ripple-marks.
Well seen on the sides of the Ressenberg and below the
Bibereck Alo.
k5. Grey, red, and variegated sandy marls, here and there,
e»()ecially towards the upper part, alternating with
sandstones, grits, and conglomerates. Well seen on the
aides of the Hornspitze, Hennarkogl.and Zwiesel Alp.
Comparing the Gosau Beds of the Gosauthal and the Russbachthal
with those of other localities in the Eastern Alps, it will be seen that
some of the beds are variable or merely of local importance, while
Lower
Gosau Beds.
Urrsu
Gosau Beds.
Vol. 50.]
GOSAtT BEDS OP THE G0SAI7 DISTRICT.
133
others are constant Certainly some are of rather variable occur-
rence in one and the aame area ; thus both the Actcconella- and
AVrmcra-limestones are absent in the Nefgraben. Hippurite-lime-
stonee, of which in different localities there may be one, two, or
three, are very poorly developed in the Gosauthal compared with
their development in the Russbachthal, while the Estuarine Beds
are altogether absent in the Goeau Valley.
At Neue Welt, near Wiener Neustadt, a locality which has been
described by Zittel and others,1 we find a Hippurite-limestone be-
tween the Act<rxmeUa- and Nerinata- limestones. The Estuarine series
is much better developed here than at the Neue Alp ; it contains work-
able coal-seams, with numerous plant-remains, freshwater shells, and
marine fossils in isolated beds, such as Omphalia, Asiarte, Circe,
Turho, etc., and reptilian remains, which latter have been described
by Bunzel and Seelev. Above the Estuarine series comes lime-
stone with AcUeojulla and other gasteropoda. The fossiliferous
marls are probably better developed at Gosau. Above this series
we see at Neue Welt what Zittel calls 4 ? Orbitulitensandstein,'
but with regard to this horizon Suess remarks, " in some places rose-
coloured limestone- bed s with Orbitoide* and the remains of a small
decapod are seen, which seem to succeed directly this zone " (t. e.
the fossiliferous marls).3 There are certainly no beds with Orbituliten
at Gosau. The next highest beds are the /noceramus-marls, the
exact position of which in the series at Gosau is uncertain. They
may correspond to the upper portion of the fossiliferous marls,
where Inoceramu* Cripsiis so common (namely, in the Hof or^raben ),
or possibly to some portion of the unfossiliferous group. The
former seems more likely to be the case.
In the Gamsthal, near Hietiau, in Styria, described by Peters *
and Redtenbacher,4 there is no Hippurite-limestone with H.
eomu-vaccinum seen immediately above the basement conglomerate.
Possibly, however, it is present here, but is not exposed. Above
the conglomerate, we find here Afertnipa-limestone, followed by
freshwater beds with coal ; then sandstones come on, followed by
./Icfceone&i-limestone and Hippurite-limestone ; then sandstones
passing into massive fossiliferous marls, on the same horizon as the
fossiliferous marls of Gosau; and finally Orbitulite-beds, corre-
sponding with those of Neue Welt.
In the Zlam Valley, near Aussee, the basement-conglomerate
system is very thick, and is followed by a series of marls, with some
limestones. This locality is described by Sedgwick and Murchison 1
and Peters.'
» Zittel, Denkachrift. d. kaietnrl Akad. Wiswnach. Wien, vol. nr. (1866)
pt ii. pp. 160 et teqq.
a Note to SeeWs paper 'On the Reptile Fauna of the Gosau Beds,* Quart.
Journ. Qeol. 80c. voL xxxvii. (1881) p. 703.
* Abhandl. d. k. k, geol. Reiohaaott toI. i. (1862) pt i.
4 Jahrh. d. k. k. geol. Reichsannt. vol. zxiv. (1874) pt. L pp. 1-6.
» Trans. Geol. Soc. 2nd eer. voL in. pt. ii. (1832) p. 362.
* Op. tupra cit.
134
MR. H. KYNA6T0N ON THE [May 1 894,
The upper un fossil if erous Beries seems to be more extensively
and massively developed in the Gosau district than in any other
locality.
Thus, on the whole, the Gosau Beds of the Gosau Valley corre-
spond very well with those of Neue Welt, Gamsthal, aud Zlam, and
in the same way it might be shown that they correspond with those
of St. Wolfgang and other areas. In short, the Gosau Beds might
be briefly described as a series of conglomerates, sandstones, and
marls, of varying thickness, constituting a complete formation
with a peculiar and at the same time extremely rich and varied
fauna, occurring in isolated trough-shaped areas in the Upper
Triassic and lihretic limestones of the Eastern Alps. In the lower
part of the series, at the margins of the trough-shaped areas, are
the most varied alternations of rock, and also the greatest abundance
of organic remains, while in the upper part of the series, at least n
the Gosau district, the rocks are monotonous and barren.
III. Paleontology of the Gosau Beds.
A rich and varied fauna is known from the Gosau Beds, and by
fur the larger majority of the species are peculiar to them. The
corals, foraminifcra, polyzoa, and eutomostraca have been described
by Reuss; the lamellibranchiata by Zittel; the gasteropoda by
Zekeli, Reuss, and Stoliczka ; the cephalopoda by Franz von Hauer ;
and the reptiles of Neue Welt by Bunzcl and Seeley. (See Biblio-
graphy, p. 122.)
Most of the organic remains occur in the fossiliferous marl-series,
while a good many are found in the Estuarine group and the lime-
stone-beds below it. Hippurites are extremely abundant, though local,
and build up great banks or reefs of hard limestone : Hipp, cornu-
vaccinum being the commonest species. Reef-building corals are
extremely plentiful* especially in the Nefgraben. It is interesting
to notice the almost entire absence of echinodermata, which are
so characteristic a feature in the Upper Cretaceous rocks of North-
western Europe, such as Hola*Ury Micraster^ Erhinoconu*, etc. ; also
the great scarcity of cephalopoda and brachiopoda, while the lamelli-
branchiata and gasteropoda are extremely abundant. The reptile
fauna described by Seeley comes entirely from the Estuarine Beds
of Neue Welt. These beds also contain the remains of a highly
heterogeneous flora, comprising a true palm, together with Pecopterii
Zippeiy Mirrozaviia, Cuntthghamites, and leaves of a dicotyledonous
tree resembling maguolia, etc., evidently the mingling of the
younger dicotyledonous type with a number of surviving older
forms.
The first intimation of the existence of a freshwater fauna in these
beds was given by Dr. Homes, who in 1856 mentioned a MelanopsU
PicMeri among the Gosau fossils collected by Herr Pichler in the
Brandenberger Ache, in the Tyrol. This gasteropod was discovered
at two localities in the Brandenberger Ache. In one place it is found
in great quantities with Chemnitzia Beyrich (Zek.), while NervHxa
Vol. 50.] GOSAU BEDS OF THE 003AU DISTRICT. 135
Buthi (Kefst.) and Adaonella Renauxiana (d'Orb.) also occur.
At the other locality it was found only with innumerable Chemnitzia>y
in a dark argillaceous marl, with thin layers of coal. The above-
mentioned Chemnitzia Begrichi is, however, probably not a true
Chemnitzia, and strongly resembles the shell described by Stoliczka
as Melanin granulato-cintta.
Cephalopoda are rare in the Gosau district, the majority of the
species described being from other localities. Brachiopods also are
of extremely local occurrence ; the following, however, occur in
the Russbachthal, on the Traunwand : —
Terebratula biplicata (Sow.).
Terebratulina grot ilia (Schl.).
Waldkrimia tamarindtts (Sow.).
Rhynchonella compresta (Lam.).
Thecidium? Wttherelli (Dav.).
Moreover Thecidium ornatum (Suess) and Crania ? sp. occur in
the Hofergraben. From other localities we get : —
Terghratula biplicata (Sow.). Abtenau and Piesting.
Terebratulina striata (Wahlb,). Near Piesting.
Waldheimia tamarindtts (Sow.). Abtenau.
lihynckonella compressa (Lam.). Griinbach.
Out of the 140 species of corals, described by Reuss, only 29 occur
in other besides the Gosau Beds. The genus Cyclolites is extremely
common throughout, especially tho species C, hemUphariea and
C. dincoulta. Amongst other very common and characteristic forms
we may mention Trochosmilia complanata (E. & H.), the genus Mtro-
camia, and Montlivaltia rudis.
Of the lamellibranchs, of course the RudisUx are extremely
characteristic and numerous; the following species are known from
the Gosau Beds : —
Radiol it en Mortoni (Mant.).
Spha*rulites angeiodes (Pic. de Lap.).
■ ttyriacus (Zitt.).
Piagioptttckm (Capritta) Aguilloni
(dOrb.).
Hippurites cornu-vaecinum (Bronn).
sulcata (I)efr.V
Touragianus (d'Orb.).
dilatatus (Petr.).
ejcaratus (Zitt.).
organ isans (Montf.).
Amongst the others, Janira (NeitJua) quadricostata (Sow.),
Panopxva frequent (Zitt.), and Cardium productum (Sow.) are ex-
tremely common. Cuculltm ckiemiensis (Giimb.), Crassatella wiacro-
donta (Sow.), and Inoceramus CVt/wi (Mant.) are also common, and
appear rather to characterize the upper portion of the foasiliferous
marls.
I did not find Cardium (Protocardia) hillanum (Sow.), Trigonia
limbata (d'Orb.), or Pectunculus Marrotianus (d'Orb.), which are also
fairly characteristic forms, the latter two being common in the Hofer-
graben, and the Pectunculus also in the Wegscheidgrabeu. The fol-
lowing freshwater bivalves occur in the Estuarine series : —
Cyclas grtgaria (Zitt.) St. Wolfgang, Neue Welt, Neue Alp.
. — — aml/igua (Zitt.) „ „ „
Ci/rena solUaria (Zitt.) Neue Alp.
Unio cretacau (Zitt.) St. Woitgang, Griinbach.
136
MR. H. KYNASTON ON THE
[Mny 1894,
Amongst the gasteropoda, AmpuUina (or Amauropti*, originally
Natica) bulbiformu (Sow.) and Natica lyrata (Sow.) occur in
thousands ; also Ceriihium reticotum (Sow.). Zekeli described about
47 species of Ceriihium from these beds, but these were reduced to
about a third of that number by Stoliczka, on the ground that many
of the species were founded on broken fragments of the spines of
other species, or were established on insufficiently constant characters.
Thus the species Cerithium reticotum (Sow.) includes C. pustulosum
(Sow.), which is merely a variety and passes imperceptibly into the
type, C. eribriforme (Zek.), C\ lucidum (Zek.), C. daxlaium (Zek.),
and several others. Glauconia (or OmpJialia) Kefersteini (d'Orb.)
is found with Act<ronclla at Traunwand and in the brackish-water
beds of the Estuarine series at Neue Welt. Nerinata nobilit
(Miinst.) and N. Buchi (Kefst.) both belong to the limestone-beds
(AVrtiuM-limestone), which come above the lowest Hippurite-lime-
stone. Nerinara Jbxuosa (Sow.) and N. gracilis (Zek.) seem to
belong to definite zones, in which they occur in swarms, rather low
down in the fossiliferous marl series. ActaoneJJa is very charac-
teristic : A. gigantta (Sow.) occurs in great numbers in con-
glomerate and coarse sandstone, frequently in a rather crushed
condition, in the Rontograben. Volvulina T<rvi* (d'Orb.), originally
assigned to the genus Volvaria and then to AcUronellay is also of
rather local occurrence, but is very common where it does ocour.
Aporrhai* (Alarid) costata (Sow.), originally assigned to JiosUllaria^
is extremely common in most localities. Several species of Foluto
were described by Zekeli, but these hsve all been assigned to other
genera by Stoliczka, such as Volutilithet, Neptunea, Mitra, etc,
thus : —
Valuta Bnmni (Zek.) = Vdutilithcs acuta (Sow.).
raricotta (Zek.) = Casparini (d'Orb.).
crenata (Zek.) = Neptunea crenata (Zek.).
crietata (Zek.) = Iditra cancellated (Sow.).
Fu*us cingulatus (Sow.) is very common, especially in the Edel-
bachgraben : Stoliczka, however, doubts whether this form really
belongs to the genus Fusus.
The outer shell of both gasteropoda and lamellibraochiata is, on
the whole, by no means well preserved in the fossiliferous marls, so
that specific identification is frequently somewhat difficult. Perhaps
the lamellibranchiata are generally the better preserved of the two,
the gasteropoda being more apt to get broken or merely to be
preserved as casts. Cerithium and Turritella are generally fairly
well preserved, and the shells of Melania and Tanalia in the coal-
bearing beds of the Neue Alp are exceedingly tough, though gener-
ally rather flattened by pressure.
By far the larger majority of the Gosau fossils are peculiar to
these beds, only about 124 species out of considerably over 500
occurring in other formations outside the Eastern Alps, and the
distribution of these we shall have now to consider in discussing
the geological horizon of the beds.
Vol. 50.]
(jOSAC BEDS OF THE G08AU DISTRICT.
137
IV. Geological Horizon op the Gosau Beds.
This question can be considered from two aspects : (a) strati-
graphically, and (6) palseontologically.
(a). As we have already seen, the Gosau Beds almost everywhere
rest with a marked unconformity upon the older Alpine Triassic
and Rhaetic limestones, and only at one locality do they rest on
older Cretaceous beds. However, the section at Urschlauer Achen,
near Salzburg, which I refer to, establishes the fact that the Gosau
Beds are younger than the Gault. The Gosau fossils from this locality
occur, according to Dr. Oppel,' in a dark marl, which is overlain by
Orbitulitenkalk, and rests on Neocomienmergel with Criaceras;
this in turn rests on Kimmcrid^ekalke. Sedgwick and Murchison
supposed that the lowest Hippurite-limestone rested unconformably
on the older Alpine limestone, and that the Gosau Beds overlay un-
conformably the Hippurite-limestone ; but it has since been conclu-
sively shown that the coarse basement-conglomerate comes below
the Hippurite-limestone, and appearances only can be said to lend
any support to the view that the conspicuous banks of Hippurite-
limestone rest immediately against the older Triassic rocks, and that
the rest of the Gosau series does not follow them in conformable
sequence. Also tho Gosau Beds are never seen to pass upward into
any younger formation. Sedgwick and Murchison supposed that
the unfossiliferous sandy marls, sandstones, and grits at the top of
the Gosau series of the Gosautbal were of Tertiary age,a while on
palseontological grounds they believed that the fossillferous series
represented passage-beds between the Upper Chalk and the Lower
Eocene. But we shall see from pakeontological considerations that
the fossiliferous series caunot represent such passage-beds. It
passes up imperceptibly into the unfossiliferous group, and there is
a very gradual dying out of molluscan remains, so that no definite
line of demarcation can be drawn between them. The majority of
authors who have written on the subject decidedly agree in regarding
the Gosau Beds as constituting one complete formation, which is
singularly isolated stratigraphieally. Wo shall find that more im-
portant results will follow from considering the question of the
geological horizon.
(6). In doing so, it may be as well, first of all, to summarize the
opinions of the various authors who have expressed views on
palieontological grounds as to the age of the Gosau Beds.
Ami Boue studied the Gosau Beds in the neighbourhood of
Griinbach, Neue Welt, in 1822. He took them at first for Jurassic,
but subsequently changed his opinion in 1824, and correlated them
with the Greensand or Quadcrsandstcin.3 Keferstein 4 included the
1 ZitUl, DenkBchrift.d. kaiserl. Akad. Wissensch. Wicn, toI. xxt. (1866) pt. ii.
p. 162.
5 Trans. Geol. Soc. scr. 2, toI. in. pt. ii. (1832) p. 359.
' 8ee Zittel, op. tupra cit. p. 174.
* * Geologie von Teutscblaud,' toI. 1827.
U. J. G. S. No. 198. l
138
MR. H. KYNASTON ON THE
[May 1894,
Oosau Beds together with the Vienna Sandstone in the FlyBch,
although Count Miinstcr 1 had already collected a number of un-
doubted Cretaceous fossils from the neighbourhood of Gosau and
Abtenau.
Sedgwick and MurchiBon, as we havo already seen (op. cit.\
placed the lowest Hippurite-limestono below the whole of the
Gosau scries, and regarded the ibssiliferous marls as passage-beds
between the Secondary and Tertiary systems, and the upper unfos-
siliferous group as Tertiary, on tho same horizon as the Molasse.
Goldfuss, who described a number of fossils from the Gosau Valley,
left the question of the age of the beds open. After the year
1830 geologists were, on the whole, fairly well agreed as to the
Upper Cretaceous age of the Gosau Beds, though we still find
Klipstcin in 1843 upholding their Tertiary age.3 Murchison,
following up the investigations undertaken in conjunction with
Sedgwick, published in 1849 a paper on the Geological Structure of
the Alps, Apennines, and Carpathians.3 In this he changes his
former opinion, and believes that the fossiliferous beds of Gosau are
the equivalents of the Gault, Upper Greensand, and Lower Chalk.
He still, however, thinks that tho upper part of the Gosau series
without fossils represents a portion of the Xummulitic and Flysch
series of other districts, while the Hippurite-limestone is the equi-
valent of the Neocoraian.
Franz von Hauer in 1850* correlated the Gosau Beds with the
Obere Kreide and the Planer- and Quadersandstcin formation of
Northern Bohemia and Saxony, and later (1878), in his * Geologic
der bsterr.-ungarischen Monarchic ' (p. 510), he classes them as
Turonian, and places the Nierenthaler Schichten, which occur at
Nierenthal in Bavaria and near Gmunden in Cpper Austria, in the
Senonian with BehmniteUa mucronata and Ananchytes ovata.
Up to about this date the fauna of the Gosau Beds was very
imperfectly known, and it was from the want of a more accurate
knowledge of this and of Cretaceous faunas in general that the
idea of their Tertiary or Cretaceo-Eocene age had been entertained
by some of the earlier observers. Probably, also, the generally
soft and rather crumbling nature of the deposits, and tho loosely-
embedded mode of occurrence of the fossils, seemed to lend support
to this view.
In 1852 Zekoli published a monograph on the gasteropoda,1 in
which ho concluded that out of 190 species only 23 occurred outside
the province of the North-eastern Alps, that the fauna showed a
highly specialized facies, and that it would be difficult to correlate
the beds with any known Cretaceous formation. Out of the 23
1 Count Minister's collection is now in Uie Woodwardian Museum, Cam-
bridge.
- ' Beitrage zur geologiachen Kenntniss der ostliehen Alpen,' p. 24.
:| Quart. Journ. Geol. Soc. rol. t. p. 157.
4 Juhrb. d. k. k. geol. Reicbsanst. toI. i. p. 44.
4 'Die Gasteropoden der Goaaugebilde, Abbandl. d. k. k. geol. Eeicbsanst.
vol. i. pt. ii.
Vol. 50.]
GOSAU BKDS OF THE GOSAU DISTRICT.
13i>
already known species Zekeli found that 11 occurred in the Turanian,
7 in the Senonian, 3 in the Turanian and Senonian together, and
2 in the Gault ; so he concluded that the Gosau Beds represented
both the Senonian and the Turanian.
In 1854 Reuss 1 described the foraminifera, polyzoa, en torn -
ostraca, and corals of the Gosau Beds. He found that, of the species
of Gosau fossils known elsewhere, by far the greater number appear
in the Turanian system of d'Orbiguy, and that therefore tho
Gosau Beds reprevsent the Turanian. The Turanian character,
according to Ileuss, comes out especially in the calcareous and marly
beds, characterized by their abundance of Iiudistfe, corals, Nerituea,
and Actatonella. He thinks, however, that some of the lower beds
of the Senonian system may be represented at Gosau and elsewhere,
and formulates his conclusion thus (p. 46) : — " The Gosau Beds
constitute a complete and unique formation, in which marls, lime-
stones, calcareous sandstones, and conglomerates alternate irregularly
with one another, and this formation should preferably be correlated
with the Turanian system, and perhaps the uppermost beds with
the lower part of the Senonian system." Reuss's results would
certainly require further confirmation, since at the time when he
wrote there were no descriptions of tho Gosau cephalopoda, brachio-
poda, or lamellibranchiata. Giimbel follows iicuss, and calls tho
Gosau Beds Turanian.2
In 1865 and 18GG appeared Zittel's monograph on the lamclli-
branchs.3 Out of 140 species here described, 88 are peculiar,
while the remaining 52 occur in other places. These 52 are dis-
tributed as follows : —
In the Neocomian and Gault we get : —
Modiola aqualis (Sow.). — Neocomian and Quadersandstein (Bohemia);
Ittoceramu* Cripsi (Mnnt.).— Gault to Upper Chalk, very common in
North -western Europe,
to which I may add Cardita Unuicotta (Sow.) — Gault, found by me,
I believe for the first time, in the Hofergraben.
In the Cenomanian (Upper Greensand, Carontonian, Lower
Qnadersandstein) we find 20 species, among which I may mention : —
Tapes fragilis (d'Orb.).
Circe duetts (Math.).
Cardium productum (Sow.).
Protocardia hillana (Sow.).
Trigonia scabra (Lam.).
Modiola aqualu (Sow.).
Gerviltia toletutides (Defr.).
Inocrramus Cripsi (Mant.).
lotus (Mant.).
Janira quadricostata (Sow.)
Ostrea vesicuiaris (Lam.).
and the majority of these are best represented in the Turanian.
In the Planer of North Germany, Saxony, Bohemia, and Silesia we
find 17 species, and 17 species also in tho Quadersandstein. In the
1 ' Beitrage zur Charakteristik der Kreideachichten in den Ostalpen,' Denl-
achrift. d. knieerl. Akad. Wissensch. Wien, toI. rii. p. I.
* ' Geogno»ti«*he Beschreibung d. Bayeriecben Alpengebirges,' pt. i. p. 517.
1 Denkschrift. d. kaiaerl. Akad. WisMnwh. Wien, tol. «ir. pt ii. p. 105, &
vol. xxt. pt. ii. p. 77.
L 2
140
MR. H. KYNA8TON OK THE
[May i894r
Upper Chalk with Belemnilella mucronata of Northern Germany
and Northern France we find 18 species, amongst which are : —
(Nil*.).
virgatus (Niks.).
j productum (Sow.).
Trigonia limbata (d'Orb.).
Pinna creiacea (SchL).
GerviUia mlenoidt* (Defr.).
Inoccramm Cripri (Mant).
Lamar cki (Park.).
latm (Mant.).
Lima dccussala.
cretotws.
memhranaceu* (Nil* ).
ra quadricoUata (Sow ).
aubstriatocostata (Sow.).
Osirea vencidaris (Lam.).
»»
organisans (Montf.).
Spharuliie* an anodes (Pic. de Lap.).
Caprina AguiUoni (d'Orb.).
In the sub-stage Campanien we find 13 species.
„ „ Angoumien „ 7 „
Mornasien „ 15 „
Provencien „ 15 ,,
Out of the 15 Provencien species 7 are only found elsewhere-
in the Gosau Beds, and these 7 aro all RudisUr, namely : —
Hippurite* dilatatus (Defr.).
(Bronn).
suicatu* (Defr.).
Toucaxianu* (d'Orb.).
These are, of course, extremely characteristic and common, and
belong to the most characteristic forms of the zone of HippuriU*
cornu-vacexnum, which forms one of the best-marked horizons in
the Cretaceous system. Zittel concludes from his study of the
distribution of the Gosau lamellibrancbs " that the Gosau Beds
belong to the zone of Hijtpurites cornu-vaccinum. or Stage Pro-
vencien (Coquand), and do not represent the Turonian and Senonian
combined." He finds that this conclusion is also supported by the
facts of the distribution of the gasteropoda and corals. Of the
brachiopoda none are restricted to any definite horizon. Thus, out
of the 8 species known, we find : —
2 in tbe Neocomian and Gault.
5 ,, Cenoiuanian.
2 „ Planerkalk.
1 „ Lower Chalk.
2 „ Santonian.
3 „ Upper Chalk with
Stoliczka reduced the gasteropoda
nearly 200 species to about 124. By
these are confined to the North-eastern Alps, only a small number
occurring in the South of France. Out of the 26 species which
occur outside the Eastern Alps we get, according to Zittel, 21 in
the Provencien, of which 14 occur in the blue marls of Corbieres.
Among them we may mention : —
Act<eonella nigantea (Sow.).
described by Zekeli from
far the larger majority of
Volvulina Levis (d'Orb.).
KcrinoHi littchi (Kefst.).
Omphalia Ktjcrsteini (Miinst.).
lirnauxiana (d'Orb.).
Ampullina (yatica) buUAformu
(Sow.).
Jiatica lyrata (Sow.).
angulata (Sow.).
Funis cingidatus (Sow.).
Alaria cottata (Sow.).
granuiata (Sow).
Asiraiium radiatum (Zek.).
Fhasianel/a gotauica (Zek.).
Cerithium furcatum (Zek.).
reticosum (Sow.).
provinciate (d'Orb.).
Vol. 50.]
UOBAU REDS OV THE GOSAU DISTRICT.
141
Out of the 140 or more species of corals, most of which are
peculiar to the Gosau Beds, 20 are found in the Provencien.
Thus, taking the corals, bivalves, and gasteropoda together, we find
56 species in the Provencien, and this is a far larger number of
•species than is found in any other sub-stage, according to Zittel.
He finally concludes that the Gosau Beds are Turonian, that they
belong only to the zone of Hippurites cornu-vaccinum (Provencien),
and that they represent a unique and remarkable development of
that horizon, indicated by the richness of their fauna and its
large number of peculiar forms.
There seems no doubt whatever that the Provencien zone of
Hippurites cornu-vaccinum occurs in the lower part of the Gosau
series ; but it does not follow that the Gosau Beds merely represent
a remarkable development of this one horizon only. It is, indeed,
by no means easy to correlate these beds exactly, seeing that we
have no stratigraphical data and considering their peculiar fauna,
with any well-known zone or zones of Western Europe ; nor does
there seem to be an entire agreement amongst geological writers
as to exactly what should constitute the Turonian and what the
Senonian system. Possibly some confusion might be avoided if
these terms were altogether ignored in a discussion of this sort,
and reference only made to zones, which are probably, under the
present methods of stratigraphical enquiry, a surer indication of
a geological horizon than names for systems and stages which can
only have a more or less local significance.
Zittel occupies tho last part of his monograph with a sketch of
the principal features of the strata included in the sub-stage Pro-
vencien of the South of France, and with a few remarks on tho
wide distribution in Southern Europe and Asia of the zone of
Hippurites cornu-vaccinum. The term * Provencien,' however, does
not seem to have come into general use, many geologists including
the zone of Hipp, cornu-vaccinum in the sub-stage Angoumien ;
but this is not of any particular importance. A mere question of
terms cannot alter a geological horizon.
As an oxample of the confusion which may arise from the use of
the terms * Turonian ' and ' Senonian ' in connexion with such
stratigraphically isolated deposits as the Gosau Beds, I will quote
two passages, both from the pens of eminent geologists. In
1881 appeared Prof. H. G. 8eele/s description of the Reptile Fauna
of the Estuarine Series of Neuc Welt,1 appended to which was a note
by Prof. Suess. In this, however, Suess omits to mention the occur-
rence of Hippurite-limestone below this series in the Gosau Bods,
and finally remarks, " I cannot, therefore, say positively that the
age of the Reptiles .... is exactly that of your Cambridge Phos-
phate-beds ; but it is certain that they are older than the true
Turonian deposits, and especially older than the zone of Hippuritt*
cornu-vaccinum." Turning now to Toucas's paper,8 entitled 4 Syn-
chronisme des Etages Turonien, Senonien et Danien dans 'e Nord
1 Quart. Joura. Geol. Soc. voL xxxrii. p. 620.
2 Bull. Soc. G60I. France, aer. 3, vol. x. pp. 200-202.
142
MR. II . KYXASTON ON THE
[May 1894,
efc dans le Midi de l'Europe,' published in 1882, we read (p. 200) :
. " All are agreed in recognizing the essentially Scnonicn character of
the Gosau fauna/' But he goes on to say that Zittel, Keuss, and
others were " misled by the papere of d'Orbigny, and especially by
those of Coquand on tho Turonian and Senonian of the South of
France, and particularly as to the position which they assign to the
Hippuritc-deposits," so that "in default of other terms of com-
I»arison " they correlated the Gosau Beds with the Turonianr
Since, however, Toucas's conclusions in his valuable paper referred
to above seem to be extremely important, it will be well to look
into them more closely. Apparently Zittel modified his former
views as to the age of the Gosau Beds alter comparing them, in
company with Toucas, with the beds of Beausset in the South
of France ; and now Zittel classes as Senonian the Hippurite-beds
of La Cadiere and Beausset, as well as the marls and limestones
with Inoceramus digitatus which support them.
The beds of La Cadiere, Beausset, Sougraigne, and other places
in the South of France, belong to the zones of Belemnitella and the
2nd zone of Hippuriies, and have been correlated with the Gosau
Beds.
Toucas finds 19 species of fossils common to the Gosau Beds and
the Senonian zones of Ceratitts and Micraster brevis of Provence
and Corbiercs, LS to tho Gosau Beds and the zone of Inoceramus
digitatus, and 63 common to the same beds and the zones of BeUrm-
nitdla and the 2nd zone of Hippurites. He concludes that the
distribution of the Gosau fossils proves that the Gosau Beds repre-
sent tho whole of the Senonian from the Craie de Villedicu to the
zone of Btlemnitella inclusive. It is true, as Toucas remarks, that
we do not find in the Gosau Beds a single characteristic Turonian
species such as Ammonites RequUni, A. jKramplus, A. papal is,
A. Deveri, A. nodosoides, nor any of tho Rudisia* such as Hipp.
Requiem, liadiolites comu-pastoris, SpJurrulites ponsianus, so
abundant in the first zone of Hippurites, which he places at the top
of the Turonian. Furthermore, the presence in the Gosau Beds of
Amm. texanus, A. subtricarinatus, A. Margiv, Humites cylindraceus,
etc., certainly indicates a post-Turonian age, occurring as they do
in the zone of Inoceramus digitatus.
But still there seems to be some slight confusion with regard to
the Rudista. In the Gosau Bods, as we have already seen, Hippurite-
limestones occur at two distinct horizons ; thus we get the Ilippu-
rite-liraestone immediately above the basemen t-conglomeratey
characterized essentially by Hipp, cornu-vaccinum. This is overlain
by the Actaondla and iSViWa-limestoncs and the Estuarine Beries,
and then we get Hippurite-limestono occurring again in the fossili-
ferous marls, this time characterized essentially by Hipp, organisans,
while Hipp, cornu-vaccinum, SpJurrulites angeiodts, and Plagiopty-
chus (Caprina) Aguilloni also occur. Now, in the South of France
also, Toucas distinguishes two distinct zones of Hippurites : the
first, which he places at tho top of the Turonian system, is the
zone characterized essentially by Hipp, cornu-vaccinum ; while in
Digitized by Google
Vol. 5o.j
OOSAU BEDS OP THK GOSAU DISTRICT.
143
the second, which he places towards tho top of the Senonian, we
find Hipp, organisans, Hipp, cornu-vaccinum, Sphfrndites angeiodes,
and Plagioptychtt* Aguilhni (op. eit. p. 202).
Toucas soems to have lumped together all the species of Rudista
fonnd in the Gosau Beds, and to have referred them to his 2nd zone
of HippuriU*. But surely it would he more natural to keep the
two Gosau zones separate, since stratigraphies! evidence is so
strongly in favour of their being distinct, and to correlate them
with the 1st and 2nd zones of Ifippurite* respectively of the South
of France. Thus we should have the zone of Hijtp. cornu-vaccinum
remaining intact near the base of the Gosau series, and being the
equivalent of the uppermost portion of the Turonian system of
Toucas. We should hardly expect to find at Gosau such ammonites
as A. Requieni, A. peramplus, A. papalis, A. Deveri, A. nodosoides,
since the majority of these occur in the South of Frauce below the
first zone of Hipimriles, or the zone of Hipp, comu-vacc mum, which
zone is the first stratum of tho Gosau Beds wherein any fossils
occur.
Dr. Emmanuel Kayser alludes briefly to the Gosau Beds in his
4 Lehrbuch der geologischen Formationskunde ' (Stuttgart, 185)1),
and remarks (p. 280) that the lower beds belong to the Turonian,
and the higher to tho Senonian. Toucas's objection to any part of
the Gosau series being considered as of Turonian age is that, when
one does find Turonian species in them, such as thoso of Uchaux in
the South of France, they are only those which pass up into higher
beds. But when we consider how strong the evidence is in favour
of the occurrence of the true zone of Hipp, cornu-vaccinum at Gosau
and other places in the Eastern Alps, and bearing in mind the con-
siderations brought forward above with regard to the two zones of
Hippurites, we cannot but conclude that the basal portion of the
Gosau Beds should be correlated with the zone of Hipp, eomu-
vaccinum, included in the first zone of Hippurites at the top of the
Turonian system.
Passing from the zone of Hipp, comu-vaccinum to the .Senonian
zones of Provence aud Corbieres, we find (Toucas, op.cit. pp. 210-
217) that the larger proportion of the fossils from the Gosau Beds
occur also in the zone of Belemnitella and the 2nd zone of Hip-
purites in the upper part of the Senonian. Hence we shall not bo
far from the mark in concluding that the Gosau Beds represent tho
uppermost Turonian, and tho whole of the Senonian ot tho South of
France — that is to say, from the zone of llippuritex cornu-vaccinum
to the zone of Belemnitella inclusive. In Touraine and in the Paris
Basin the same horizon is defined from tho zone of Amm. Requieni
in Touraine [=zone of Hoi aster planus and Am. peramplus in
the Paris Basin] to the zone of Belemnitella mucronata, and hence
in the English Upper Cretaceous rocks we shall find the repre-
sentatives of the Gosau Beds in the zones of Holwtter planus,
Mic raster, Marsujnits, and Belemnitella mucronata — that is to say,
from the horizon of the Chalk Rock to the top of the Chalk-with-
flints inclusive.
144 a a. h. KYNA8T0N on thb [May 1894,
If we endeavoured to correlate the Gosau Beds with English Cre-
taceous zones by a direct comparison of their fauna with English
Upper Cretaceous faunas, we should find a rather difficult task
awaiting us. There are very few fossils common both to the Gosau
Beds and the English Upper Cretaceous rocks ; and those Gosau
species which are found in England are, as a rule, not confined to
any particular horizon, but frequently have a fairly extensive dis-
tribution in the Cretaceous system.
From Murchison's paper, 1 as we have already pointed out, we
may gather that he correlated the Lower or more fossiliforous portion
of the Gosau Beds with the Gault, Upper Grcensand, and Lower
Chalk, while he assigned the Hippurite-limcstone to the Neocomian.
But he still clung to the idea that some of the Upper part of the
series might represent passage-beds from the Chalk to the Tertiary
system. Hence, the whole of the Gosau Beds would represent,
according to his views, all the English formations from the
Neocomian to the top of the Chalk, and would furnish the missing
overlying passage-beds as well. But, as these views have been
already discussed, we need not enter into them further.
Judging from Suess's Note, appended to Prof. Seelcy's paper, a
few remarks from which I have already quoted, we may conclude
that Prof. Seelcy had some idea that the Estuarine beds of the Gosau
series, from which the reptilian remains so admirably described by
him were collected, might be on the same horizon as the Cambridge
Greensand. But, as we have already seen, from a comparison of the
Gosau fauna with the Senonian and Turonian faunas of the South
of France, it is highly probable that the Gosau Beds commence with
the zone of Holaster planu* or the Chalk Rock, whereas the Cam-
bridge Greensand occurs at a very much lower horizon, namely at
the base of the Chalk Marl. At the commencement of his paper,
too, Seeley speaks of the Gosau Beds as " nearly corresponding in
age to the Upper Grcensand of this country," and in consequence of
this we find that some of the reptiles he has described are referred
to in Nicholson and Lydekker's 4 Manual of Palaeontology ' as
occurring in the "Upper Greensand of Austria" (see vol. ii.
pp. 1160, 1163).
Seeley revised Bunzel's work on the * Reptiles of Neue "Welt/
published in 1871, and described altogether 14 genera and 18
species, and all the specios are peculiar. There are certainly 7
Deinosaurs, 1 each of Crocodiles, Lizards, and Pterodactyls, 2 genera
and 5 species of Chelonians. Out of the 14 genera only the fol-
lowing 5 are known in England : — Crocodilus, Mtgalosaurus^
Ornilhoc7ieiru4, Hoplosaurns^ and Emt/8. The Crocodilus is charac-
teristic of Tertiary and Recent times ; Mtf/alosaurus ranges from
the Lower Jurassic to the Upper Cretaceous of Maastricht ; Ornitho-
clieims characterizes Cretaceous rocks, Hoplosaurus Wealden ; and
Emys ranges from the Lower Eocene (or Gosau Beds, according to
Seeley) to recent times. The only two genera of these which occur
in the Cambridge Greensand are OrnitJiocJieirus and Crocodilus, and
of these the latter genus does not seem to be recognized as of
1 Quart. Joum. Geol. Soc vol. v. (1849) p. 157.
Digitized by Google
Vol. 50.]
UOBAU HEDS OF THE GOSAU DISTRICT.
145
Cretaceous age by Lydekker. Thus we cannot hope to get much
result from studying the reptiles of Neue Welt as to the geological
horizon of the beds in which they occur.
Neither do we get any further help from the cephalopoda, as
none of them are characteristic of any particular English horizon,
the form best known in England, viz. Scaphites osqualis (Sow.),
ranging from the Gault to the Chalk Rock.
Probably none of the Gosau species of gasteropoda occur in any
English Cretaceous beds whatsoever. It is doubtful whether
Aporrhnis calcnrata (Sow.) of the Gault and Upper Greensand of
Blackdown occurs at Gosau, the form from Gosau, originally named
RosUUaria calcarata (fctow.), having been assigned by Stoliczka to
Alt Ha (probably Ajxnrrhais) granvlata (Sow.). In fact only a very
few gasteropoda at all are common to the Gosau Beds and the North
of Europe, e. g. Turritefla Eichwaldiana (Goldf.), occurring in the
Upper Chalk of Haldem : Nerinoxa Buchi, N. jUxuosa, and Vdvu-
Uua lavis^ in Bohemia; Natica lyrata, in North Germany; and
Fusus Nereidis (Miinst.), in the Chalk of Haldem.
Coming now to the lamellibranchiata, we find the following
Gosau species in English Cretaceous beds, with the subjoined dis-
tribution : —
Neocomiaw Modiola tt</uali& (Sow.) Atherfield.
/ Cardita tenuicastata (Sow.).
I Grrvillia solenoid es (Defr.).
Gaclt 1 Ostrea vesicularis (Lam.).
] J antra (NeitAea) quadricostata (Sow.).
\Inoccramu* Cripsi (Mant.).
' Protocardia hillana (Sow.) .
Gcrvillia mfenoides (Defr.) .
Janira (Seithea) quadricos-
tata (Sow.).
Cypricardia testacea (Zitt) .
Isle of
Lower Chalk ....
Cardita tcnuicostala (Sow.)
Gervillia soknoides (Defr.) . I
Ostrea veticulari* (Lain . ) ... <
Janira (Neithea) quadricos-
tata (Sow.)
Blackdown.
Warminster.
Blackdown and
Wight.
Cornea very near Ct/prina
cuneata (Sow.) from the
Blackdown beds.
( Gault forms occurring as
derived fossils in the Cam -
I bridge Greensand (see
GeoL Surv. Mem. on
Geology of Neighbour-
hood of Oambridge, p.
152).
Mwni.8 Chalk
Ui per Chalk
Ostrea vesicularis (Lam.).
Rpondylu* siriatw (Sow.).
Mortvni Also in Cambridge Green-
sand.
Inoceramu* I at us (Mant.).
f Ostrea vesicularus (Lam.).
"'[ Inoccramus lotus (Mant).
( Ostrea vesicular is (Lam.).
Pecten virgotus (Nilss.).
crelosu* (Defr.).
j lootu (Nilss ).
1 Janira (Neithea) substriatocostata (Sow.).
Inoceramm CHpsi (Mant.).
Lamarcki (Park.).
_ lotus (Mant.).
146
MB. H. KYNA8T0N ON* THE
[May 1894,
Thus we find that the Neocomian has 1 Gosau species, the
Gault 5, the Upper Greensand 3, the Lower Chalk 4, the Middle
Chalk 2, and the Upper Chalk 8. Although there are not many
of these species which are confined to definite horizons or zones,
yet the outcome of this direct comparison tends to confirm the result
already arrived at.
Of the brachiopoda found in the Gosau Beds the following occur
in England : —
Rhynchonella comprcssa (Lam.)
Terebratula bijdica ta (Sow. ) . . .
Terebratutina gracilis (Schl.)
striata (Wahlb.)
Waldhcimia tamarindus (Sow.)
Thecidium WethereUi (Dst.) ?
Range — Xeoooinian to Upper Chalk
(Norwich).
„ Gault to Lower Chalk («. of
Holaster subi/lobostia).
Chalk Marl to* Upper Chalk
„ Chalk Marl to Upper Chalk (x.
of BcltmniteUa mucronata).
,, Neocomian to Lower Chalk.
„ Lower Chalk to Upper Chalk.
The range of these species is too wide for accurate correlation
purposes, though it will be observed that out of the 6 species we
have 4 in the Upper Chalk, 4 in the Middle, and all 6 in the
Lower Chalk. Taking the lamellibranchiata and brachiopoda
together as they are distributed in the Chalk, we have, in the
Lower Chalk 10 species, in the Middle Chalk 0, and in the
Upper 12.
Thus the former conclusion, that the Gosau Beds represent on the
whole the Upper Chalk, is by no means weakened, and from the
considerations brought forward al)ovo we may conclude that they
represent in Britain the Chalk Rock or zone of Holaster planus, and
the whole of the Upper Chalk up to the zone of Btlemnitella mucro-
nata inclusive.
It stands to reason that all discussion of the geological horizon of
the Gosau Beds on palacontological grounds will not necessarily
apply to the Upper or unfossiliferous portion of the Gosau series,
namely, the sandstones, flags, and shales, with obscure plant-remains
and worm-tracks, and tho system of grey and red sandy marls.
And since tho fossiliferous portion of the Gosau series brings us up
to the zone of Belemnitella mucronata, there is no reason why the
upper unfossiliferous beds should not represent part of the so-called
Danian Beds of other districts, and be on the same horizon as the
chalk of Maastricht, Ciply, and Aix-la-Chapelle ; or are we to
include this upper portion also in the Senonian ? The question,
however, cannot be answered positively, and must be left open for
the present. Hence wo may conclude this section with the following
table of correlation between the Gosau Beds and the English Upper
Cretaceous zones : —
Vol. 50.]
GOSAU BKDS OF THE 608AU DISTRICT.
147
Gosau Bids.
' Upper Series of Marl*, ^
Sandstones, etc., with
obscure plant - re-
mains, and wonn-
E.vglisu CnALK Zones.
► (Absent)
?Dakia».
( Fossiliferous Marls and") f Zone of Bekmni- \
2nd ione of Hippu- telta mucroruzta j TjPPWt
r»/«,E8tuarineSeries, y ■{ Zone of Marmtpitcs } «
Limestones with Ac- [ Zone of Microliter,
)
Senonian.
Limestones with Hipp. J fZone of Ho/aster J \r..,
comu-mccinum and I \ ptanu* or Chalk I «...
Conglomerate J | Bock J UU
• I.E \
L.K. J
TvaoviAR.
V. Physical History of the Gosau Beds.
Probably the whole series of the Gosau Beds was deposited in
fairly shallow water. At the base wo find conglomerates, marls,
and limestones, with Hippurites, Achronelki, Cerithium, Xeriiura,
etc., beds which are evidently of marine origin, and the limestones
are almost entirely made up of forms which most probably dwelt in
shallow water. The Hippuritts lived in colonies, like oysters, and
built up great banks or reefs, resembling barrier-reefs, along the
rocky coasts of older Triassic and Rha;tic limestones, whose frag-
ments constitute the basement-conglomerate. Above the limestones
wo find a series of beds containing a fauna consisting of a mixture
of marine and freshwater forms and land-plants. This probably
indicates the neighbourhood of the mouth of a river. Stoliczka,
referring to the nature of these bods, remarks : — 44 Ono can see
from these occurrences that during part of the Cretaceous period the
valleys of our Alps stood high enough above the sea-level for fresh
water to flow down them. These streams or torrents, with their
unusually richly ornamented molluscs and the strange assemblage
of plants on their banks whose remains have formed the small layers
of coal, give the palaeontologist a characteristic illustration of a
mountain-region in the Chalk period." 1 But I fail to see how the
facts illustrate any such thing. The organic remains in the beds
certainly prove that they were deposited near the mouth of a river,
and possibly part of them may be entirely of freshwater origin,
but it seems highly improbable that they could have been deposited
so far above the sea-level as to give us molluscs and land-plants
of a mountain facies. The whole assemblage denotes estuaririe
conditions ; and the floor of this estuary evidently underwent gradual
depression, as we find the brackish-water beds gradually passing
into the thick series of fossiliferous marls with their rich and
entirely marine fauna. Here, again, we find Hippuritc-banks and
1 SiUungaber. d. kaiserL Akad. Wissensch. Wien, vol. xxxtiii. (185») p. 48L'
148
MR. H. KVNABTON ON THE
[May 1894.
coral-reefs, and the whole is of a littoral facies and denotes a tropical
climate.
When we reach the top of this series, however, conditions seem
gradually to have altered, and we find quite shallow-water deposits
constituting the micaceous sandstones and flags, with occasional
bands of coarse grit. The abundant ripple-marks, worm-tracks, and
obscure remains of plants and fragments of wood are sufficient proof
of their shallow-water origin and the proximity of land. The mica
so abundant in those beds was probably derived from the denudation
of some of the older schistose and gneissic rocks of the central
portion of the chain. Depression, however, gradually followed
again, and we get beds of rather deeper- water origin, viz. the sandy,
red, grey, and mottled marls, without any organic remains, and
these again are succeeded by shallower-water beds, forming the
grits and conglomerates at the top of the whole series. There is
nothing to prove whether these unfossiliferous beds were of fresh-
water or marine origin. It is evident that elevation was going on
towards the close of the period in which the fossiliforous marls were
deposited, and it is rather difficult to account for so complete,
though so gradual, a change in the lithological and paheontological
character of the rock, unless we suppose that at about that time the
Gosau district was cut off by this elevation from free communication
with the open sea, and constituted for the rest of the Cretaceous
period a lake-basin.
Since the Gosau Beds of the Gosau Valley are tilted up so that
their average dip is in a southerly direction — and the dip is frequently
steep in the northern part of the valley, while most of the beds
towards the south, especially on the Ressenberg, are almost hori-
zontal— it would follow that the greatest amount of elevation took
place in the northern portion of the area, especially since we find
there the basal conglomerate at almost as high a level as the marl
series of the Hornspitze. Land evidently lay to the south in the
direction of the central axis of elevation of the Eastern Alps, and
open sea to the north and north-west. Now it is in the north and
north-west of the area that the beds are much tilted and disturbed,
and in the south that we find the micaceous sandstones and sandy
marls. Hence, if this elevation of the northern part of the area,
which, as we have seen, began towards the close of what may be
called « the fossiliferous period/ continued to any great extent, the
southern portion would have been cut off from communication with
the sea, and so would have constituted a lake-basin, with a river
running into it from the south.
The occurrence in the upper unfossiliferous beds of ripple-marks
and worm-tracks would rather seem to negative the idea of lofty
mountainous features existing in the immediate neighbourhood,
since lakes in mountainous districts usually have steep, shelving
sides, which would not allow of the tranquil deposition of sediment
in very shallow water on an almost horizontal floor.
Several authors havo supposed that the Gosau Beds were de-
posited in bays or fjords represented by parte of the present
Digitized by LiOOQle
Vol. 50.]
fiOSAU BKDS OF T1IE GOSAU DlSTRlCf.
149
valleys of the Alps.1 But the mode of occurrence of these beds
does not necessarily prove that tho present valleys of the Eastern
Alps were already marked out in Upper Cretaceous times. What
we can say for certain is that they were deposited in trough-shaped
depressions in the older Secondary rocks, and we should naturally
expect, under these circumstances, that the present lines of drainage
would cut through them where opportunity occurs, since they would
be of a much more yielding and easily-disintegrated nature than the
older rocks on which they rest.
Sedgwick and Murchison, struck by the isolated position of the
Gosau Beds, supposed that several of the now-isolated patches were
originally connected, and were deposited in a deep bay within the
.Vlpine chain.* Probably many such patches, like those of Zlam,
Gosau, Abtenau, aud St. Wolfgang, were originally continuous, arid
were deposited in bays on the southern boundary of the great Upper
Cretaceous Sea of Central and Southern Europe. Otherwise it is
difficult to account for tho succession of strata being almost the same
in each case, if we suppose that the now-isolated patches existed as
such at the time of deposition.
From the stratigraphical situation of the Gosau Beds, and the
occurrence of the calcareous conglomerate at their base, it is evident
that the older Secondury rocks of the Eastern Alps on which they
rest had undergone elevation and denudation, with a considerable
amount of earth-movement, accompanied by contortion and plication,
previous to the period of depression during which these beds wen-
deposited. During their deposition the Eastern Alps probably
existed as fairly high land along the central portion of the chain,
with a very irregular coast- line along its northern flanks. At the
close of Cretaceous times there was probably considerable elevation,
followed by depression in the Eocene period at tho time of the
deposition of the Nummulitic rocks and the Flysch. Then followed
the period of the great Alpine uplift, a movement intense in the
western portion and gradually dying out towards tho east in the
direction of tho Vienna Basin, and it is to this period that the
present structure of the mountains is chiefly due, as also tho present
isolated and elevated position of the several small areas covered by
the Gosau Beds.
VI. Summary.
It now only remains to summarize briefly the description
which 1 have given of the stratigraphy, palaeontology, physical
history, etc., of the Gosau Beds of the Gosau district.
After an account of the previous literature of the subject had
been given, and tho physical aspects of the Gosau Valley had been
described, I pointed out that the Gosau Beds are found in various
isolated trough-shaped depressions chiefly on the northern flanks of the
Eastern Alps, such as tho Gosau Valley, the Zlamthal (near Aussee).
1 Zittel, Penkschrift. d. kaiserl. Akad. Wi«cnach. Wien, vol. xxv. (1866) pt. ii.
p. 160.
2 Trani. Geol. Soc. ter. 2, rol. iii. pt. ii. (1832) p. U67.
Digitized by LaOOQle
150
MR. H. KTN ASTON ON THE
[May 1894,
the Gamsthal in Styria, the basin of St. Wolfgang, and Neue Welt,
near Wiener Neustadt. With one exception they are always found
resting unconformably on the older Secondary rocks of the Alps,
and with one exception again are never associated with either
older or younger Cretaceous beds.
Iu the Gosau district they dip on the average in a southerly
direction, and the degree of inclination varies from almost hori-
zontal in the more southerly part of the area to an angle of about
60° towards the north and north-west. The Gosau Beds of this
district correspond on the whole in their fauna and stratigraphical
divisions with those of most of the other areas, and they consist of
conglomerates, limestones with HippuriUs and corals, estuarine beds
with a mixed fauna, dark-grey marls crowded with molluscan
remains, and micaceous sandstones, flags, and shales, sandy marls
and grits, etc., without any fossils.
The fossils from the Lower beds constitute a rich and varied
fauna, in which corals, gasteropoda, and lamellibranchiata are
especially well represented, while cephalopoda and bracbiopoda are
comparatively rare, and echinodermata almost entirely absent. The
greater majority of the fossils are peculiar to these beds. Those
species which are found in other areas seem to prove that the
Gosau Beds are of Upper Cretaceous age, and that they represent
the whole of the Senonian, and the uppermost part of the Turonian
system of the South of France — that is to say, from the zone of
I/ij>puritex cornu-vaccinum to the zone of Belemnitella inclusive, or
in England from the zone of Holaster planus or the Chalk Rock to
the zone of Belemnitella mucronata inclusive, while the Upper un-
fossiliferous portion of the series may possibly represent the Danian
system.
The Gosau Beds are, on the whole, of shallow-water origin, with
beds indicating estuarine conditions near their base, and were
deposited in narrow bays in the Upper Cretaceous Sea of Southern
and Central Europe on the northern flanks of the Eastern Ali>s.
Probably, towards the close of Upper Cretaceous times, the southern
area of the Gosau district was cut off from the sea so as to consti-
tute a lake-basin, in which the Upper unfossiliferous series was
deposited.
The Gosau Beds owe their present isolated and elevated position
to the last gTeat period of mountain-building in Central Europe,
which took place at the close of the deposition of the Nummulitic
series and the Flysch.
Discussion.
The President said that the Geological Society must ever take a
deep interest in the district referred to in this paper, in consequence
of the classic memoir by Murchison and Sedgwick published many
years ago. Since then the district had been investigated by several
distinguished geologists, and we were indebted to the Author for his
excellent summary of the present state of our knowledge as to the
Digitized by LiOOQle
Vol. 50.]
GOSAU BEDS OF THE Q08AU DISTRICT.
if>i
stratigraphy, palaeontology, and physical history of these interesting
deposits. No doubt there had been much pre-Cretaceous oscillation
in that area before the deposition of the Gosau Beds. Whether the
study of them will ever throw light on the question of Alpine up-
heaval appears doubtful. He would like to ask the Author whether
there was any evidence of the existence of a central crystalline axis
during the deposition of the Gosau Beds. As to correlation with other
strata in North-western Europe, it was curious to note the occur-
rence of so many reef-building corals and gasteropoda in beds
parallel with the Micraster-chalk in England.
Mr. W. Whitakkr, Sir John Evans, aud Prof. J. F. Blakb also
spoke.
The Author, in replying, said that a considerable quantity of
white mica occurred in the flaggy beds of the Upper Gosau series.
This he regarded as indicating the existence at that time of schistose
rocks belonging to the axial portion of the chain to the south. As
regards the correlation of the Gosau Beds with British Upper
Cretaceous zones, he considered that such correlations were always
useful, if not necessary ; and although the Gosau Beds could not be
directly correlated with English rocks, they could bo closely com-
pared with the Turonian and Senonian zones of the South of
France, which in their turn could be correlated with the Upper
Cretaceous zones of the Paris Basin and England. The Gosau Bods
represented, on the whole, a distinctly littoral type of formation,
and certainly could be made use of in searching for the shore-
line of the Upper Cretaceous Sea in Central Europe.
Digitized by Google
152
PBOF. E. HULL OK AN ABTKSlAlf B0RIN6 [May 1 894,
11. Abtkslak Boring at New Lodok, near Windsor Forest (Berks).
By Prof. Edward Hull,; M.A., LL.D., F.R.8., F.G.S. (Read
December 20th, 18D3.)
Havlng availed myself of the opportunity offered by a few weeks'
residence in the neighbourhood of Windsor Forest, during the summer
of 1893, to visit a remarkable boring for water carried out at New
Lodge in Berkshire, of which notices appeared in several newspapers
some little time ago, I propose to lay before the Society the infor-
mation obtained on the occasion referred to, Monday, the 28th August
last.'
The boring was carried down by means of the diamond drill at
the rear of New Lodge, the residence of Mr. Van de Weyer, at
a level of about 220 feet above Ordnance datum, and commences in
the London Clay not far from the base of the Bagshot Sands, which
set in a short distance southward in the direction of Windsor Forest.3
Without going into minute details of the boring, the following
nummary will Buffice to show the nature of the strata passed through
from the surface to the total depth of 1241 feet3:—
Thickness
in Feet.
t«tu«... { Te^i- ::. } »*
( Chalk (Upper and Lower) 725
Cretaceous J Upper Greeusond 31
Strata. { Gault Clay 204
^ Lower Greensand 7
Total 1241
When the boring was commenced it was expected that it would only
be necessary to enter the Chalk in order to find the requisite water-
supply, and a diameter at the surface of 1\ inches was considered
sufficient to allow for tubular lining to this depth. Much dis-
appointment was, therefore, felt when it was found on reaching this
formation, at a depth of 215 feet, that the rock was hard and contained
very little water ; and it was thereupon determined to continue the
boring down into the Lower Greensand — as the next most likely
source of supply. W ith a diameter at the commencement of only
7£ inches some anxiety was necessarily felt as to whether this
formation could be reached by means of a tubular bore with the
necessary lining ; and, as the result proved, the apprehension was
well founded. But fortuno was on the side of the exj>eriment. The
borer entered the Lower Greensand with a diameter of \\ inch,
and had not penetrated into this formation for more than 7 feet
1 1 hare to acknowledge the assistance and information readily afforded by
Mr. Menxiea, of Englefield Green, and by Mr. Rose, the bailiff of the estate.
a That the locality was originally part of this extcnaiTe forest is sLown by
the presence of several noble oak-trees of great age.
J The work was carried out by the firm of Le Grand and Sutcliff, London.
Digitized by Ls00j9l£
Vol. 50.]
AT NEW LODGE, NEAB WINDSOR FOREST.
1
when the water gradually rose in tho borehole, reaching the surface
and even rising 7 feet above it in a pipe. Of course, with so
small an orifice (1£ inch) in the water-bearing beds a large supply
was not to be expected ; but, notwithstanding, the supply is suffi-
cient to give a continuous flow of 2 gallons per minute, equal to
2,880 gallons per day, and quite ample for the requirements of a
very large household. The water is soft, clear, and slightly
chalybeate.
From the above account we may gather several interesting con-
clusions. Firstly, it will be evideut that the hydrostatic pressure
is very great, being sufficient to cause the water to rise 7 feet above
the ground in a pipe ; and we may therefore suppose that with a
wider borehole a much larger supply could be obtained. We may
also infer that the surface gathering-ground of the Lower Greensand
is considerably more elevated than the site of tho boring. The Lower
Greensand crops out at about an equal distance of 20 miles north and
20 miles south of the boring: the one outcrop being in Buckingham-
shire, and the other in Surrey, near Guildford. But the surface-area
in the former case is interrupted and never extensive, while in the
latter it is continuous, elevated, and extensive. To this latter source
we may therefore attribute the underground supply at Windsor
Forest; and we may affirm with considerable confidence that under
the Windsor district large supplies of excellent water might be
obtained by borings carried out on a sufficient scale into the Lower
Greensand, should the supply from the Chalk fail.
It is very probable that the Lower Greensand is altogether cut
out by the ridge of Mesozoic or Pahpozoic rocks, which may be
presumed to extend under the Valley of the Thames at Windsor ;
for it will be recollected that in the Richmond boring there was a
thickness of only 10 feet of this formation.1
Taking the district from Dorking to Selborno, the Lower Green-
sand has a range of nearly 30 miles from east to west, with a general
dip towards the north and north-west, and an average exposed
surface of 5 to 7 miles wide (as, for example, nt Haslemere), giving
au area of 150 to 180 square miles. As this formation is exceedingly
open and porous, and is destitute of superficial covering, except the
soil, the proportion of the rainfall that enters the rock and constitutes
a permanent source of supply must be very large indeed ; perhaps
not less than two-thirds of a rainfall of about 28 inches, or 18 (5
inches, sinks down into the beds, the remainder being evaporated.
The ground occupied by the formation is very elevated, several points
1 The magnetic survey of the British Isles, carried out by Profs. Riicker and
Thorpe, indicates that between Windsor and Reading there exists 'a high peak'
of old rocks rich in iron, and sending off ridges in the direction of Oxford
towards the north-west, and Cambridge towards t he north-east. In this locality
the magnetic disturbance due to such concealed rocks is remarkable — causing
a variation of the needle, both as regards dip and horizontal force, altogether
unusual. This peak is overlain by the Chalk in the Valley of the Thames, but
is probably sufficiently high (so to speak) to dissever the Lower Cretaceous
beds of the south from those which reach the surface in Oxfordshire. See Phil.
Tram*. Roy. Soc. vol. cUxxiii. a (1890) p. 2ts3.
Q.J.G.S. No. 1<J8. m
Digitized by Google
Digitized by Google
Vol. 50.] ARTESIAN BOBING NEAR WINDSOR FOREST. 155
reaching levels between 800 and 900 feet above Ordnance datum.
For example, the broad plateau of Hindhead, south of Farnham,
reaches an elevation of about 900 to 910 feet where crossed by one
of the sections of the Geological Survey (Sheet 73); also at the
Royal Huts Inn the surface rises to 840 feet, and at Gibbet Hill to
895 feet, according to the Ordnance Survey. The average lovel of
this broad tract of Lower Greensand about Haslemere may be taken
at about 600 feet, which is nearly 400 feet higher than the surface
of the ground at the boring at New Lodge, Windsor ; so that we can
account for the great hydrostatic pressure of the water at this spot,
notwithstanding the long distance that it has to travel through the
mass of the formation itself. Doubtless the whole formation under
the Chalk is waterlogged ; but it should be recollected that when
reached by a well or borehole the supply derived from the imprisoned
water in the underground reservoir may gradually fall off, and the
supply then becomes dependent on the annual percolation. This has
been found to be the case with wells in the New Red Sandstone.
Discussion.
The President said it was satisfactory to learn that there was an
area near West London in which the Lower Greensand was full of
water. He thought that the section exhibited by the Author ex-
plained why it was full in that particular locality, for the rainfall
about the extensive area of Hindhead, which lay nearly due south,
must be considerable.
Mr. W. J. Lewis Abbott wished to ask if Prof. Hull had any
absolute data upon which to bring up this Palaeozoic ridge to
within 200 feet of O.D., as shown in the section. He would be
glad to know whether, in the boring, the Folkestone Beds showed any
lithological change, such as would bo expected, had that part of the
beds been deposited along the shallow sea of a Palaeozoic island-
ridge. The extended outcrop of the Greensands wag quite sufficient
to account for their superior yield of water.
Mr. W. Whitaker also spoke.
The Author replied.
u 2
uigm
156
PROF. T. RUPERT JONES ON THE
[May 1S94,
12. On the Rustic and some Liassic Ostracoda of Britain. By
Prof. T. Rupert Jones, F.R.S., F.G.S. (Read January 10th,
1894.)
[Platb IX.]
Coktkits. Tage
I. Published Observation in Chronological Order 156
II. Named Specimens l«r>9
III. Description of the Species 162
I. Published Observations in Chronological Order.
The occurrenco of small Ostracoda in the Rhaetic strata of
England has been known for about half a century, chiefly owing to
the researches of the Rev. P. B. Brodie, F.G.S., who discovered
tbem in the sections exposed at Wainlode, Westbury, Aust Passage,
and elsewhere.
1842-1845. — The Wainlode section is on the south side of the
Severn, about halfway between Tewkesbury and Gloucester, and
3 miles W.S.W. from Coomb Hill. It was briefly described by
H. E. Strickland,1 and more fully by the Rev. P. B. Brodie.* Since
then the Geological Surveyors and others have studied it in further
detail.3
This section shows : —
1, 2, 3. Black clay, limestone, and shale of the Lower Das.
4 [Rbajtic 4 J. Insect -bed or JUonotis-bed, containing " Cypris,
apparently identical with that which marks the yellow limestone
(No. 6) below." (' fossil Insect*,' etc., p. 59.)
5. Clay.
6. " Hard, yellow, nodular limestone, with small shells like
Cyclas, a species of Unto, Plants (Xaiades), Cypri*> and very rauly
scales of Fish." (Ibid.)
7-14. Clays, shales, and Bone-bed.
"Mr. Stricklaud has found the yellow Cy/>rw-limestone with
0//c/<w(?), the Pecten- and Bone-beds ... at Dunhamstead, on
tho line of the Gloucester - and - Birmingham Railway, near the
Droitwich Station " (* Fossil Insects,' etc., p. 72) ; and at Evesham
" are traces of the Ostrea-bcd [Lias] above and of the C^ru-bed
and Plant-bed below " (ibid.).
Among the specimens kindly lent me by the Rev. P. B. Brodie,
one piece of the * Cy/>r/#-bed,' from the Wainlode Cliff, is a hard,
sandy limestone, containing a 4 Fttromya*
1 Proc. Oeol. Soc. rol. iii. part ii. (1842) p. 58<>; ibid, vol. iv. part i. (1843)
• Proc. Geol. 8oc. vol. iv. part i. (184.^ pp. 15, 1<> ; and ' A History of the
Fo*sil Insect? in the Secondnrv Rocks of England,' 184f>, pp. ;">8, b\).
3 See II. B. Woodward's ' Geologv of England and Wales,' 2nd edit. 1887,
pp. 242- 2a 1.
* According to the arrangement adopted by the Geological Survey.
Digitized by Google
Vol. 50.] KHiTIC AJTD LIAS8IC OSTBACODA. OP BRITAIN. 157
The Garden-Cliff section, near Westbury-on-Severn, 8 miles from
Gloucester (4 Fossil Insects,' etc., p. 79), has at the top —
1 [Lias]. Ogtrea-bed.
2 [Rbsetic]. Insect-limestone, with Monotis dtctusaia.
3. Shale and clay.
4. 44 Hard, yellow, and grey limestone, often slaty and sandy, . . .
with supposed Cyclas^ Plants {Naiades), Cypris, and scales of Fish
identical with those at Wainlode."
5. Shale and clay.
6. Bone-bed. This series is stated to be *• more developed . . .
a little further to the north." At p. 80 it is stated that " The
Plants (Naiadita lanceolata) and Cypris are here much more
abundant, the surface of the slaty portions being covered with
remains of the latter Crustacean, which are collected together in
masses of some thickness, just as we find them in many freshwater
deposits. . . . We have [here] a new and highly interesting featuro
in the history of this deposit. . . ." 1
The section at Aust Passage on the Severn, about 80 miles S.W.
of Tortworth and 12 miles from Bristol (4 Fossil Insects,' etc.,
p. 82), consists of : —
1. Rubble ; 6 feet. 2 [Lias]. Oyster-bed, one of five beds of
stone; 4 feet. 3. [Rhaetic]. Landscape-stone; 5 feet. 4. Clay;
2 inches. 5. White stone : Cypris- and Plant-bed with Cydas ? ;
6 feet. 6. Clay ; 3 inches. Below this are the Pecten-bed with a
clay and the Bone-bed.
At p. 102, op. nt.t the Rev. P. B. Brodie includes in his list of
fossils : —
44 Cyjrris Uassica (Brod.), page 80 (Cypris-bed), Wainlode, West-
bury, Bickmarsh, Bedminster,3 Aust.."
1848.— In 1848, H. G. Bronn (4 Index Palaw>ntologious,' vol. i.
p. 389) refers to " Cypris liassica, Brod. foss. ins. 80, 102 (an
Cytheriwx, sp.?)."
1854. — In 1854, J. Moms (4 fetal. Brit. Foss.' 2nd edit. p. 104)
refers Cypris liassioa to " Brodie, Foss. Ins., p. 80. Lias. Wain-
lode."
1855. In the Mem. Soc. Geol. France, ser. 2, vol. v. part ii.
p. 333, and pi. xxvi. fig. 12, O. Terquem figured and described an
Ostracod as Cypris Uassica, Brodie. But it does not correspond
with any of our Rmetic forms, and was found in marine beds of the
Lias in Luxemburg and the Department of the Moselle.
1861. — Mr. Charles Moore, after careful studv of the Rtuetic
formation, noticed the occurrence of 4 Cypris ' and 4 Cypridce ' in
the White Lias of the Rhaetic formation,* and particularly of u
1 Mr. Brodie adds in a footnote to this passage : — 4 1 propose to call the
Cypris Cypri* lioBtica, as it is the only one of the kind at present known in that
formation' [then regarded as Lower Luis, but afterwards (1865) known as
Bbtctic].
2 For C. Moore's notice of the section at Bedminster, near Bristol, see
Quart. Journ. Geol. Soc. rol. xxiii. (1867) pp. 500, 501.
■ Op. cU. voL xrii. (1861) p. 49G.
Digitized by Google
158
FROF. T. RrPBRT JONES ON TUE
[May 1894,
form which he referred to 44 Cypris liassica, Brodie," at Beer-
Crowcombe, Stoke, Vallis, etc.1
The section at Beer-Crowcombe a shows : —
1 & 2. Some beds of the Lias, of and above the Am. pl<tnorh!s-
zone. 3. The Saurian Bed. 4 [Rhaetic]. The White Lias. 5. The
Avimla-contorta-zone. 6 [Trias]. The Keuper. No fossils are here
especiaUy mentioned.
One of the Ostracoda collected by C. Moore at Beer-Crowcombe
has been kindly lent from the Bath Museum, through the courtesy
of the Rev. H. H. Win wood, F.G.S. ; it does not, however, corre-
spond to the so-called Cypris Jiassica. About the occurrence of
the latter (?) Mr. C. Moore states as follows 3 : — 44 The upper
surfaces of the blocks of 4 White Lias ' in the sections near Taunton
[Stoke St.-Mary, etc.] are frequently covered with the shells of this
little Crustacean. The same conditions prevailed when the 4 Flinty
bed' at Beer-Crowcombe was deposited, as the shells are very
numerous on its weathered surface. In the Vallis section it is very
rare, and only represented by a single specimen, attached to a
fragment of Lima precursor."
1805. — The Rev. P. B. Brodie mentioned the occurrence of the
Cypris-bed at Wootton Park, near Henley-in-Arden, in the Quart.
Journ. Geol. Soc. vol. xxi. p. 160; and at p. 161 he expressed
his opinion that this and the associated strata, below the Saurian
Bed, would probably come 44 within the Rhaetic series of the Trias."
1865. — Messrs. J. W. Salter and H. Woodward's 4 Descriptive
Catalogue of a Chart of Fossil Crustacea ' contains figures of
two 4 Rhaetic ' ( ? ) Ostracods from Somerset, enumerated at
p. 21, as [fig.] 44 87, Cy there Jiassica, Jones, MS.," and 44 88,
Cythere, sp. nov., Jones, MS." There is some confusion here, for
the specific name given to fig. 87 is Brodie'e, not Jones's ; nor is it
the 4 Cypris liassica,' but some foim of Cythtridea. Fig. 88 is
probably of the same species as that represented by fig. 6 in
PI. IX. Although the sketches for figs. 87 and 88 were
supplied by me in 1865, all trace of them and of the specimens has
been lost. These latter, however, may possibly have been found by
me in some probably Lower-Liassic limestones near Tauntor.,
Somerset.
1867. — Mr. C. Moore recorded the occurrence of 4 Cythere liassica *
in the 4 Rhaetic White Lias 'of the Camel Hill Railway -cutting 1
on the Wcstbury-and- Weymouth line. Mr. E. Wilson has remarked 5
that the fact of some of the whiter beds of the Lower Lias, as well
as some of the Upper Rhaetic, having both been termed 4 White
Lias,' leads to occasional confusion. He also informs me that
Mr. C. Moore's 4 List of Fossils ' at p. 465, vol. xxiii. op. cit., shows
that it is a mixed series of Rhaetic and Lower-Lias species ; or it is
1 Quart. Jouro. Geol. Soc. vol. x*ii. (1861) p. 514.
a Ifnd. pp. 485, 486.
3 Ibid. p. 512.
4 Quart Journ. Geol. Soc. rol. xxiii. (1867) p. 405.
8 Op. cit. vol. xlvii. (161*1 ) p. 546.
Digitized by LiOOQle
Vol. 50.] En^nC AND L1A88IC OBTHACODA OP BRITAIN. 159
even possible that all the 4 White Lias ' here alluded to may
belong to the Lower Lias.
Mr. Moore also mentions as occurring at the Willsbridge cutting
on the Mangotsfield Railway,1 44 2 b. Laminated light-blue clay,
with Esthtria rninuta [var. Brodieana ?], Cythere liassica, Avicula
decussata, etc.", lying on a representative of the well-known Land-
scape-stone. He further remarks2: — 44 The surface of the laminated
clay (2 b) is often entirely covered by Cythere liassica, the specimens
being generally so uniformly arranged lengthwise as to show the
direction of the current of the water by which they were last
washed."
1876. — In that part of R. Tate and J. F. Blake's work on the
4 Yorkshire Lias ' which treats of the Crustacea, the Rev. J. F. Blake
describes and figures a really Liassio Ostracod (p. 430, pi. xvii.
fig. 1) as 4 Bairdia liassica, Brodie, sp.', which belongs to a
different genus (probably Cythcridea). It is not like Brodie's
4 Cypris liassica,1 referred to above, and of which a labelled
specimen is preserved in the Geological Society's Collection. Nor
does it agree with M. Terquem's description and figures of Terquem's
Cypris liassica* from the Lower Lias of Zetrich, Halberstadt,
Metz, and Jamoigne, which is probably a Cytheridea, and included in
Mr. Blake's synonyms (op.cit. p. 430). In the same list, " 1872,
Bairdia [?] eUipsaidea [G. S. Brady, MS. J, Jones, Quart. Journ. GcoL
Soc. vol. xxviii. p. 146," with a slightly modified description of
the latter, and with some additions, is used for the Bairdia liassica ,
loc. cit.
1877. — H. Woodward, in his 4 Catalogue of British Fossil Crus-
tacea,' p. 102, refers to 44 Cythere liassica, Brodie, sp., 1843, Rhaetic ;
Wainlode, Severn." ,
II. Named Spbcimess.
Of authentically named specimens of Brodie's 4 Cypris liassica '
I can find only one or two good examples in the Geological Society's
Collection ; but none in the British Museum (Natural History), nor
in the Museum of Practical Geology. Nor is there a good published
figure of that species.
Other hand-specimens, with Ostracods incorrectly named 4 lias-
sica,* are also here enumerated.
I. In the Geological Society's Collection, at Burlington House,
are some specimens of cream-coloured limestone full of obscure
plant-remains, and bearing a few indications of a small Ostracod.
These arc labelled : 44 Naiadites acuminata, Buckm., Geol. Chelt.,
p. 03; Rhastic; Bristol; Cypris liassica, Brodie. Rev. P. B.
Brodie, F.G.S."
The above-mentioned specimens exactly correspond in aspect and
» Quart. Journ. Geol. Soc. toL (18G7) p. 498. 2 Ibid. p. 499.
3 Mem. Soc. Geol. France, aer. 2, tol. t. purt ii. (1855) p. 333, p!. xitI.
figs, 12 a, bt c.
Digitized by Google
PROP. T. Bt> PERT JONES ON THB
[May 1894,
contents to some pieces of Rhcctic limestone from Pylle Hill, near
Bristol, sent to me by Mr. E. Wilson, F.G.S., in 1891, and noticed
by him in Quart. Journ. Geol. Soc vol. xlvii. (1891) pp. 545-549.
They are similar also to a specimen from Uphill, near Weston-
super-Mare, collected by Mr. C. Moore, aud now in the Bath
Museum.
In the Geological Society's Collection there are also three
pieces of the " Cypris-bed with traces of, small plants ; Westbury.
Mr. Brodie." One piece shows an edge-view of what seems to be
an internal cast of Darwinula liassica.
In one of the drawers of the Collection is an old label purporting
to be a •* List of fossils from the Lower Lias of Gloucestershire : —
44 Insects, Wainlodes Cliff.
•4 Insect-limestone aud Cypris-bed, Wainlodes.
# 44 Insect-limestone and Cypris - bed, Westbury, and minute
plants."
These above-mentioned specimens may well have been those
presented by the Rev. Mr. Brodie in 1842 1 as 44 Remains of Insects
and other fossila from the Lower Lias [Rhsetic ?] near Cheltenham "
[and elsewhere?].
II. The specimens lent from the Charles-Moore Collection in the
Bath Museum in 1892-93 (see above, p. 158) comprised : —
1. 44 Cypris liassica. Rba?tic Beds. Beer-Crowcombe." Con-
sisting of numerous small, oval, black, smooth Ostracoda ( Cytheridea,
see PI. IX. fig. 7), lying close together in a hard, grey marl.
2. 44 Cypris liassica (slab covered with). White Lias near Taun-
ton." A buff-coloured limestone, with numerous small, oval,
smooth Ostracoda, not so well preserved as in the grey-marl speci-
men, but apparently belonging to the same species. They lie on a
bed-plane, together with fragments of shells (Pecteri) and a piece of
an Echinid spine ; also the cast of a small furrow or trail. These
are evidently not Brodie's species ; but Mr. C. Moore seems to have
met with the real form elsewhere, judging from his remark that on
some bed-planes at the Willsbridgo cutting (see above, p. 159)
the carapace-valves lie uniformly lengthwise, as if thoy had a
relatively long axial diameter, as is the case with Darwinula
liassica.
3. A piece of cream-coloured limestone, containing fragments of
Naiadita and valves of Darwinula liassica, from Uphill, near Weston-
super-Mare, Somerset.
4. Some mounted Ostracoda, labelled 44 Bairdia liassica, Brodie ;
Lower Lias ; Brocastle," belong to the genus Cytheridca most
probably ; and are really Lower- Liassic, not Rhaetic.
III. The Rev. P. B. Brodie has kindly given me several intereRt-
ing specimens from his Collection, but only one of them yields a
form identical with * his 4 Cypris liassica ' ; and there are other
forms, of much interest, which will be noticed in the sequel.
IV. It is Mr. Edward Wilson's large series of shale and lime-
stone (from Pylle Hill, Bristol), alluded to in Quart. Journ. Geol.
1 Proc Geol. Soe. voL-ir. part i. p. oO.
Digitized by LiOOQle
Tol. 50.] RH.ETIC AND LIASSIC 08TBAC0DA OP BRITAIN'.
101
Roc. roL xlvii. (1891) p. 548, that supplies us with the best material
illustrating the particular Ostracodous forms under notice.
Old exposures at Bcdminster, near Bristol (Mr. Wilson informs
me), may have been a source for Da nv inula liamricn in former times,
for the same limestone as that occurring at Pylle Hill is evidently
referred to by the late Mr. W. W. Stoddard in his essay on the
Geology of the Bristol Coal-field, part v., in the Proc. Bristol
Nat. Soc. n. s. vol. ii. part 3(1879), pp. 280, 281, where he states :
44 Immediately on leaving Bedminster we notice, on the left-hand
side of the road and just under the reservoir, a small well, on the
top of which is a thin bed of light cream-coloured limestone full of
remains .... of Naiadite* petiolata" . . . and " valves of E§theria
and Cytheridat. Near, and behind a public-house, is a small quarry
in which is a whitish cream-coloured bed containing . . . valves of
Cytherida! in . . . abundance .... Eighteen inches above this is
the well-known Cotham marble " with Insects and Landscape-stone.
Kemains of Insects and Entomostraca were found in a bed about 15
inches above the Cotham marble. Of the beds in this little quarry
Mr. 8toddard gives a detailed section, and Mr. Wilson refers them
to a higher zone than the Naiaditet-bed above mentioned, which he
correlates with the Upper-Rha?tic bed 4 J ' of his Pylle Hill section.
He thinks that, in Mr. Stoddard's section of the quarry, beds
nos. 1-5 (21 inches thick) above the Cotham marble belong to the
Lower Lias, and beds 6-10 (21 inches of thin clays and limestones)
to the Upper Rhootic. The strata above the Cotham marble here are
said by Mr. Stoddard to comprise a bed with Monotis cUcugtata and
fish-remains (and indistinguishable from that at Garden Cliff, near
Westbury-on- Severn), overlying the bed (no. 3) with Insects.
These beds are referred to the llhaetic aeries above, at p. 156, in
accordance with the classification adopted by the Geological
Survey.
Mr. Wilson informs me that in the roadside quarry on Bedminster
Down, a little beyond the public-house referred to above, there are
now exposed beneath the Cotham marble 2 to 3 feet of shales pre-
cisely similar to bed 4 m ' of his Pylle Hill section, without any
hard beds in them.
V. Mr. William Cunnington, F.G.8., gave me some years ago
a few specimens in bluish shale from Bcdminster,1 which prove to
be D. liasxica.
Another interesting specimen from Mr. Cunnington's Collection
is a piece of greenish-grey argillaceous limostone, bearing, on a bed-
plane, a multitude of individuals of Darwinula liassica, lying in an
almost uniformly parallel arrangement, caused by the moving water
in which they were left. This is ranrked ' Clifton ' and (incorrectly)
1 Mountain-limestone/ Mr. E. Wilson, F.G.S., having examined
the specimen, states that it belongs probably to his * Upper- Kha?tic '
Series, " perhaps a hard seam in the light greenish-blue shales
marked tm' in the Pylle Hill section" given by him in Quart.
1 This ma? be the same, perhaps, as that referred to by Mr. £. Wilson,
F.G.8 , in Proc. Geol. A*oc. toL xiii. (1893) p. 129.
Digitized by Google
162
TKOP. T. KUPERT J05ES ON THE
[May 1894,
Journ. Geol. Soc. vol. xlvii. p. 546. The footnote at that page refeis
to the late Mr. Tawneys section of the Rh»tic beds at Oakfield
Road, Clifton, where they are faulted down into the Keuper area ;
and Mr. Wilson thinks that the specimen nndcr notice may have
come from that excavation.1
Other possible sources for it, he says, may be the exposures at
Cotham, Pylle Hill, and Bedminster ; but these localities could not
have been termed 4 Clifton.'
VI. We must not omit to state that from Linksfield, near Elgin,
in Morayshire, Scotland, many years since, specimens of some
similar Rhaetic Ostracoda were supplied by Mr. Patrick Duff, Mr. S.
H. Beckles, and Mr. Charles Moore, as fully acknowledged in the
Monogr. Fobs. Estherire, Pal. Soc. 1862, p. lb,
III. Description op the Species.'
1. Darwinula liassica (Brodie). (PI. IX. figs. 1 <r, 1 ft, 1 c.)
Length. Height. Thickness of carapace.
Fig. la -85 -35 — mm.
Fig. 16 -7 *3 — ram.
Fig. 1 c -65 — -30 mm.
Carapace sub-cylindrical or sub-reniform, varying in outline with
slight differences probably due to either individual or sexual growth.
The dorsal edge is more or less arched ; and the ventral is somewhat
hollowed, and more or less sinuous. The ends are rounded ; but
the front end has rather smaller dimensions than the other. Surfuce
smooth.
The left valve overlaps the right along the back, but in some
individuals uuequal pressure gives rise to a different appearance.
The original amount of convexity of the surface can seldom be
estimated, on account of the crushed condition of many specimens,
the partial embedment of others, and the rarity of exposed edge-
views. The carapace, however, is convex along the middle, and
thickest at the posterior third (fig. 1 e).
Some exposed interiors show very simple edges, always somewhat
broken.
With regard to other known species of Darwinula, it is to bo
noticed that, of several published figures of the small Ostracoda
referable to D. Uguminella 3 (E. Forbes), none exactly agree in
proportions with D. liassica (Brodie) ; and it differs also from
D. Stevensoni, Brady and Robertson,* especially in being less com-
pressed anteriorly.
1 [In this specimen from Clifton several slightly different forms nf Daneinnla
liassica are recognisable ; and indeed one relatively short form may prove to
be specifically distinct.— Feb. 17th, 1894.1
2 I have to acknowledge Mr. Frederick Chapman's kind help in preparing
and sketching most of the Ostracoda here described.
3 In the Monogr. Foes. Ettheriae, Appendix, 1862, pi. v. fig. 31 ; Quart.
Journ. Geol. Soc vol. xli. (1886) pi. viii. fig. 30; Geol. Mug. 1886, pi. iv. fig. 4.
* Ann. Mag. Nat. Hint. 1870, and elsewhere, 1874 and 1889.
.60 Uy
Google
Vol. 50 ] Rfl^TTIC A5D LIA88IC 08TRAOODA OF BRITAIN. 163
Specimens of this species in the Geological Society's Collection
came from the cream-coloured limestone with Naiadites, or 4 Vypris-
bed/ at Westbury-on-Severn (so© p. 157) ; and from a locality
at * Bristol,' which, from Mr. Brodie's information, appears to have
been on the Wells Road.1 These are similar to Mr. Wilson's
limestones 4 • ' and 4 T at Pylle Hill, from which figs. 1 and 2 have
been taken. The shale ' m ' also contains this species in abun -
dance.
It occurs in a shale from Bed minster (p. 161), probably the
same as some Rhaetic shale which Mr. Wilson has found in a quarry
on Bedminster Down,* over a mile west of Pylle Hill.
[It is present in the hard calcareous shale from the excavation
at Clifton (p. 162).— February 17th, 1894.]
Also in a dark-grey, probably Rhaitic shale 4 abovo the Insect-
limestone ' in the Wain lode section (P. B. Brodie).
A limestone, similar to that of Pylle Hill, with D. liassica and
NaiaditsSy is in the Charles-Moore Collection, Bath Museum, from
Uphill, near Weston-super-Mare (see p. 100).
1*. Darwikula liassica (Brodie), var. major, nov. (PL IX.
fig. 2.)
Length. Height.
1 mm. -55 mm.
The valve in this variety is much larger than what appears to be
the normal form ; the extremities are more unequal in size, and the
anterior is definitely smaller than the other end. (See fig. 1 6.)
This variety occurs, in company with the smaller valves (but
rarely) in the light-blue shales of Pylle Hill (' m \ E. Wilson), in
that of Bedminster, and in the shale 4 above the Insect-limestone '
at Wainlodo Cliff (Brodie). [Also in Mr. Cunnington's specimen
from Clifton.— Feb. 17th, 1894.J
2. Darwinula olobosa (Duff). (PL IX. figs. 3, 4 a, 4 b.)
Cijpru globosa, Duff, 4 Sketch of the Geology of Moray/ 1842, p. 1 0
and p. 19.
Condona ? (jlobosa, Jones, Monogr. Foss. Esthcrite, Pal. Soc.
Appendix, 1862, pp. 126, 127, pi. v. tigs. 23 and 24.
Length. Height.
Fig. 3 *95 -45 mm.
Fig. 4 a -95 -4 mm.
44 Carapace subcylindrical, smooth; carapace- valves oblong, straight
on the ventral edge, slightly arched on the dorsal, rounded at the
ends, but obliquely at the anterodorsal region, so that the fore end
is narrower than the other." The lucid spots (muscle-marks) arc
not so much like those of Candona Forbtsii (Monogr. Tertiary
1 Mr. WiUon tells me that the exposure here may have been the old Pylle-
Hill section, abutting on that road.
3 Proo. QedL A*wc. voL xiii. (189a) p. 129.
uigmz
PROP. T. RUPERT JONES 05 THE
[May 1894,
Eii torn. pi. iv. fig. 8, p. 18) as at first supposed. They are much
more like those of Dartu inula.1
The edge view of the carapace or of either valve cannot be
satisfactorily determined, because of their generally crushed state.
This species from Linskfield, near Elgin,2 is so much broader
(higher) than known DarwinuUx that it may probably belong to the
genus of that larger form, somewhat similar in shape, referred to
Cyjirione in Quart. Journ. Geol. Soc. vol. xli. (1885) pp. 343, 344,
pi. viii. figs. 27-29, 32. Of this latter, however, we do not yet
know the muscle-spot.
Darwinula (or Ci/prione?) globosa "occurs in great numbers, and
in many laminae, in the greyish calcareous shale or marl at Links-
licld ; and Estheria minuta, var. Brodieana, sometimes appears in
the same bed," Monogr. Foss. Esth. p. 127.
2*. Darwinula. globosa (Duff), var. stricta, nov. (PI. IX.
fig. 5.)
Length. Height
Fig. 5.... *9 mm. *35 mm.
In company with the usual form in the Linksficld shale another,
but rare, form, with more truly parallel and nearly straight dorsal
and ventral margin, is found.
It has a less arched back and more equal ends than the common
specimens, and may be regarded as a variety, possibly of sexual
relationship.
3. Cytiieridea ellipsoid ea (Jones). (PI. IX. figs. 6 a, 6 6, 6 c.)
Ci/there, sp. nov., Jones MS., Salter & Woodward, Descript. Catal.
Chart Foss. Crustac. 1865, p. 21, fig. 88.
Jiairrfia ? eBijHoidea (G. S. Brady MS.), Jones, Quart. Journ. Geol.
Soc. vol. xxviii. (1872) p. 140.
Jiairdia Uastica (not Brodie's sp.), Blake, 4 Yorkshire Lias,' 1876,
p. 430, pi. xvii. figs. 1, 1 a.
Length. Ileight. Thiokne.os of carapace.
Fig. 6 a .... *65 *45 — mm.
Fig. 6 6 .... '65 -4 — mm.
Fig. 6 c .... *65 — *35 mm.
Carapace almost obovate, but more highly arched at the anterior
third of the dorsal region, where the hinge is most pronounced,
making the carapace broader (higher) there than behind. The
1 Ann. Mag. Nat. Hist. ser. 4, vol. vi. (1870) pi. vii. fig. 7 ; Monogr. Post-Tert
Entom., Pal. Hoc. 1874, pi. ii. fig. 17 ; and Quart. Journ. Geol. Sou. rol. xli.
(1885) p. .T47, note.
a The shales of Linksfield. tod their fossil Entoraostracn, are treated of in
t he Monogr. Foes. Estheriae, Pala'ont. Soc. 184'»L\ }>p. 74-78; but a fuller
account both of the bibliographic history of this interesting section, nnd of its
geological and paln?ontolo>:iral characters, is gm*n in detuil by I'rof. J.W. Judd,
F.K.S., in Quart. Journ. Geol. Soc. tol. xxix. (1873) pp. 14.">-14(J.
Vol. 50.] BH^TIC LSD L1A6SIC 08TRACODA OF BRITAIN. 165
right valve (fig. 6 b) is narrower (less high) than the left (fig. 6 a),
and straighter on the ventral edge.
Being strongly convex in the middle, and compressed at the ex-
tremities, especially in front, the edge-view of the carapace is broad
acute-oval (tig. 6 c).
Surface smooth and shining ; the convexity of the right valve is
emphasized by a central swelling.
This is to a great extent comparable with two species, undoubtedly
of Cytheridea, from the FullerVearth Oolite, in plate ii. Proc.
Bath Nat. Hist. & Antiq. F. Club, vol. vi. (1889) pp. 264 & 265,
namely Cytheridea obovata, J. & 8., fig. 6, and C. suUri'jona, J. & S.,
fig. 9 ; but it differs from both of them in some details, especially in
the edge-view.
The specimens, of a reddish colour, some in a hard, and some in
a soft (weathered?) limestone, probably from the Lowor Lias of
either the Wainlode or tho West bury section (tee pp. 156, 157),
were collected by the Kev. P. B. Brodie some years ago.
Figs. 6 a, 6, c, are reductions of drawings made by my friend
Mr. J. W. Kirkby from the curious, red-coloured, little carapaces,
in hard brownish limestone, probably (Mr. Brodie thinks) from
Wainlode. He has, however, had similar specimens from either
Hatherley or Westbury ; therefore the locality is uncertain.
Besides the comparable forms noted above, there is a somewhat
similar species from the Lias of Antrim, which has been collected
by Mr. Joseph Wright, F.G.S., Belfast.
There is a noticeable resemblance of the right valve (fig. 6 a) to
the woodcut, fig. 1, p. 11, Supplem. Monogr. Tert. Entom., Pal.
Soc. 1889, representing the outline of the right valve of Potamv-
o/jtrig Brodiei, J. & S., from the Isle of Wight, but the latter is
much narrower and thinner.
4. Cttheiudea Moorei, sp. nov. (PL IX. figs. 7 a, 7 b, 7 c,
8 a, 8 6.)
Length.
Ileipht.
Thick nets of carapace
Fig.
i a
.. -65
•35
■ — mm.
Fig.
7 b . .
.. -65
•325
— mm.
Fig.
i c
.. -65
•25 mm.
Fig.
8a ..
. . ■675
•35
— mm.
Fig.
86 ..
. . *675
•3 mm.
This has a shape modifications of which are common among
Ci/tfn ritUce. Somewhat obovate, or rabtrig* nal with rounded ends;
the front semicircular, the hinder extremity contracted and elliptic-
ally rounded : the back slightly arche d, and the ventral edge oblique ;
surface gently convex, glabrous, but minutely pitted ; the edge view
of the carapace lanceolate, acute in front, and s-'tnewhat rounded
behind. In exposures of the inside the edges are set □ to be bevelled
within, and the dorsal edge bhows some taint evidence of teeth.
These are strong little valves and carapaces, almost black, congre-
gated in a bluish-grey marl from Beer-CroWCOmbe, Somerset (see
166
PROF. T. RUPERT JOXES ON TEE
[May 1894,
above, p. 160), in the Charles-Moore Collection, Bath Museum,
labelled * Cypris Uassica.' This is, however, quite different from
that form, and probably came from the Lias of the locality
mentioned.1
Being sufficiently distinct, it may be appropriately named after
its discoverer, who devoted much time and labour to the study of
the Lias and Rhaetic beds.
Numerous individuals having the same shape, but not dark-
coloured, crowd the bed-plane and constitute a small thickness of a
piece of yellowish limestone, from Long Itchington in Warwickshire
(collected by the Rev. P. B. Brodie some time ago).
With Cytheridece having this subtrigonal character we can
associate tho form described and figured by Terquem as Cypris
Uassica in 1855 (see above, p. 159) ; also Salter and Woodward's
fig. 87, ' Cytherc Uassica,1 1865 (see above, p. 158).
5. Cttheridea, sp. (indeterminable). (PL IX. fig. 9.)
Loogth. Height.
1*3 mm. -9 mm.
This seems to be the right valve of a large, smooth Cytheridta,
but it is not sufficiently exposed from the matrix for definite deter-
mination. It occurs in a small piece of compact yellowish limestone,
collected by the Rev. P. B. Brodie some years since, and labelled
* Bristol.* The matrix is not like any of the known Rb©tic lime-
stones of that locality, and it may have come from some neighbour-
ing exposure of the Lower lias.
6. Cithers beticobtata, Bp. nov. (PL IX. fig. 1 0.)
Length. Height.
1-25? mm. *7 mm.
This is a fine, strong, obliquely-subquadrate valve. The front
edge slopes from the antero-ventral corner to the anterior hinge,
and bears a thickened edge, which dies out along the oblique dorsal
margin before reaching the contracted and rounded hinder extremity.
The ventral margin is also oblique, and nearly straight as far as
can be seen. The surface is ornamented with a row of pits within
the anterior border, accompanied with parallel ridges, which, passing
along the dorsal region, are connected by an open meshwork ; and
this appears to become rather looser and less marked on the rest of
the surface, as far as exposed.
This kind of ornament is not unusual among the Cytheridcc.
Both for shape, partially, and the arrangement of riblets and reticu-
lation, some resemblance is noticeable in Cythere septentricnalis,
Brady.'
1 For the section, see Quart. Journ. Geol. 80c. toI. rrii. (1861) pp. 485, 486.
* Trans. Zool. 80c. vol. r. (1866) pl. lx. fig. 4 ; and Trans. Roy. DubL Soe.
ser. 2, toI. ir. (1889) pl. xvi. fig. 13.
Digitized by Ls00j9l£
Vol. 50.] RITiriC AND LIA98IC 0STR1C0DA OF BRITAIN. 167
The specimen under notice is in a friable cream-coloured lime-
stone full of Ostracoda (Ctfthera><?) and without NaiadiUs, from the
Rev. P. B. Brodie's Collection, labelled « White Lias, Bristol.'
Figs. 11 and 12 accompany it. Collected some years ago, it was
probably from one of the whitish beds of the Lower Lias somewhere
near Bristol, perhaps at BedminBter.
7. Ctthbre Wilsoni, sp. nor. (PI. IX. figs. 11a, 11 6, 11 c.)
Length. Height. Thickness of carapace.
Fig. 11a 1-2 '75 — mm.
Fig. 116.... 1*25 — '6 nira.
Fig. 11c — -8 '6 mm.
Carapace suboblong, smooth, elliptically rounded in front, smaller
and more svm met ri call v rounded behind. Anterior hinge well
marked ; dorsal edge rather oblique, and curving at the lower hinge
to meet the narrow end of the valve ; ventral edge somewhat
sinuous, projecting a little at the front third (fig. 11 a), but slightly
incurved behind it, and deeply sunken along the junction of the
valves (figs. 11 6, 11 c). Edge view, subacute-oval ; end view, ob-
cordate.
This is abundant in tbe piece of friable limestone which also
contains figs. 10 and 12. Collected, and formerly labelled * White
Lias, Bristol,' by the Rev. P. B. Brodie. Probably not from the
Rhjetic White Lias, but really Liassic. I name it in honour of
Mr. Edward Wilson, F.G.S., whose researches in the geology of
Bristol and its vicinity are well known, and who has obliged me
with much valuable information whilst preparing this notice of the
local Ostracoda.
8. Ctthbre, sp.? (PI. IX. fig. 12.)
Length. Height. Thickness of carapace.
1-7 mm. — *75 mm.
The dorsal aspect of an embedded carapace of a Ct/there is here
seen, such as fig. 1 1 would probably possess if it were of a larger
size. The left valve is broken at each end ; but the right valve,
excepting that the hinder hinge has been chipped out, shows a
perfect dorsal aspect.
It is in the friable whitish limestone labelled 1 White Lias,
Bristol ; ' probably Liassic, not Rhatic. Collected by Mr. Brodie.
9. Ctthbroptbboh Brobtbi, sp. nov. (PI. IX. figs. 13a, 136,
13 c, 13 d.)
Length. Height Thickness of carapace.
Fig. 13a .... -6 -45 -
Fig. 136 .... -6
Fig. 13c .... *6 — *4 mm.
Fig. 13 a* ... — -375 -45 mm.
uigm
1G3
PROF. T. RUPERT JONES 05 THE
[May 1894,
This is a small, somewhat peaehstone-shaped Ostracod, probably
a Cythcropteron, judging by its shape, more especially of that division
of tho genus embracing the C. concentricum, var. virgin™, J.1 (of
the Chalk), and the recent C. depressum and C. Urvet B. & N.a The
specimen under notice, however, though very small, is relatively
much fuller and more nearly rotund than the recent forms.
The carapace in side view is nearly oval, but subacute in front,
and quite sharp behind. The back has a semicircular curve and a
sharp edge. The ventral margin is broad, arcuate in profile, and
deeply sunken along its centre, where the edges in meeting make a
slight ridge within an inverted arch. The edge view is acute-oval ;
the end view trigonal and broadly obcordate.
This little fossil Ostracod has a distant resemblance to the cara-
pace of a Metacypris in some points as to shape, but its relationship
to Cytheropteron is much closer.
It is probably Liassic, occurring with figs. 10, 11, and 12, and is
here named after the enthusiastic veteran geologist, my respected
friend, the Rev. P. B. Brodie, F.G.S., who collected the specimen
many years ago somewhere in the Bristol district.
EXPLANATION OF PLATE IX.
(The figures are all magnified 20 diameters.)
Fig. 1. Darvrinula liaxsica (Brodie). a, right valve, large individual ; ft, right
valve, small individual ; c, edge view of carapace. Pylle Hill, Bristol.
Fig. 2. Darunnuta /tosskxr (Brodie), Tar. major, nov. Left valve. Pylle Hill.
Fig. 3. Darwinula ylohom (Duff). Left vahe. Linksfield.
Kit;. 4. Daruimda ylohom (Dull"), a, left valve ; b, muscle-spot. Linksfield.
Fig. 5. Darwinula yloftom (Duff), rar. s/ric(a, nov. Left valve. LinksBeld.
Fig. 6. Cylheridea ellipsoidal (Jones), a, left valve ; b, right valvo ; c, dor>al
view of carapace. Westbury-on-Severn ?
Fig. 7. Cylheridea Moorei, sp. nov. a, right valve; 6, left valve ; e, edge view
of carapace. Beer-Crowcombe, Somerset.
Fig. 8. Cylheridea Moorei, sp. uov. a, left valve ; b, edge view of carapace.
Long Itchington, Warwickshire.
Fig. 9. Cylheridea, sp. Right valve. Near Bristol.
Fig. 10. Cythere reticulata, sp. nov. Right valve, imperfect. Near Bristol
Fig. 1 1. Cythere H'ilsoni, sp. nov. a, left valve ; 6, veutral aspect of cara-
pace ; c, end view of carapace. Near Bristol.
Fig. 12. Cythere, sp. Dorsal view of carapace, not quite perfect. Near
Bristol.
Fig. 13. CythcTopterun Brodiei, sp. nov. a, carapace showing right valve;
b, carapace placed obliquely, with the right valve uppermost; c, dor»al
aspect of carapace ; d, end view of carapace. Near Bristol.
Discussion.
The President complimented the Author on this further addition
to the history of the Ostracoda, so many of his papers on this
subject having already enriched the Quarterly Journal. The
1 Suppl Mouogr. Cret. En»om., Pal. Soc. 1890, p. 31, pi. ii. figs. 14-17.
2 Trans. Roy. Dubl. Soc. ser. 2, vol iv. (lttoU) pp. 210, 218, etc.
Digitized by Google
Digitized by
Vol. 50. J RH^ETIC AND LIA88IC 08TRACODA OP BRITAIN. 169
present paper was of particular interest as giving a critical riiume
of the present state of our knowledge, which it appeared was very
much needed, in addition to his other work. It would be desirable to
know how far the study of the Ostracoda throws any material
light upon the change between Rhaetic and Lias, and whether the
separation was sharp or not. He also alluded to the difference
of opinion between Mr. Horace B. Woodward and Mr. Edw. Wilson
as to where the line should be drawn.
Dr. Henry Woodward also spoke.
The Author, in reply to the President's question, — whether the
Ostracoda served to decide where the line of junction between
the Rhaetic and the Lower Lias actually occurs, — stated that in
Mr. Wilson's * Upper-Rhastic ' beds Darvrinula liassica (Brodie)
abounds, and indicates either freshwater or brackish-water con-
ditions ; also at Westbury-on-Severn. Home sections near Bristol
(localities not well defined) have shown, above these beds, which
contain plant-remains (Naiadite*\ limestones with Cytheridmy estua-
rine or marine, and Cythere, a marine genus. This succession
shows that the 4 Rhaitic White Lias ' (Wilson) passed up into the
other * White Lias ' above, by one or more passage-beds, probably
included by the Geological Survey in the 4 Rbactic ' series. The
habits and conditions of recent forms of the recognized genera
supply the data for determining the probable habits of the fossil
species.
Q. J. G. 8. No. 198.
N
Digitized by Google
170
MOLLUSCS IK UPPER KKUPER AT SHREWLEY. [May I 894,
13. On (he Discovery of Molluscs in the Upper Eeuper at
Shrew ley in Warwickshire. By the Iter. P. B. Brodie,
M.A., F.G.S. (Read March 7th, 1894.)
Additional interest attaches to the green gritty marls containing
remains of Cestraciont fishes at Shrewley, lately described in my
paper read before this Society,' owing to the recent discovery of
lamellibranch molluscs at that place. Mr. K. 1\ Richards, a young
geologist, while we were working together at the quarry, drew my
attention to an impression that he had just found. Though only a
mould, I felt certain that it must have belonged to a shell of some
kind, and that it was something quite new in the British New lied
Sandstone, and therefore of some value. On a later visit I obtained
several specimens belonging apparently to more than one genus. I
sent my collection, amounting to fourteen specimens, to my friend
Mr. JL B. Newton, of the British Museum (Natural History), and
I requested Mr. Richards also to forward Mb to the same gentleman.
In consequence of this, Mr. Newton read a short paper at the
meeting of the British Association at Nottingham about them, and
he recognized three apparently marine forms, belonging, as he thinks,
to three distinct genera.3
As Mr. Newton points out, up to the present time, this is the
only record of any true shells being found in the Keuper in this
country, and this fact renders the discovery of greater interest and
importance.
A shell resembling a Modiola was said, on good authority, to
have been met with in the Upper Keuper at Pcndock, in Worcester-
shire, many years ago, but it cannot now be found, and no further
account was given of it. The matrix at Shrewley Quarry is
unfortunately most unfavourable for the preservation of tcstacea,
and it was very difficult therefore to determine those now, for the
first time, detected in the New Red Sandstone in Britain.
The shells are fairly abundant, and they occur as far as can be
ascertained at one end of the section, just above the red marl at
the base, though they may be present in the same position else-
where, and if the green marls could bo got at, which cannot now
be done, other and better specimens might bo secured. Mr. Newton
proposes to describe them in more detail and to give figures of the
best examples.
Discussion.
Mr. R. B. Nkwton referred to the indebtedness of the Society to
Mr. Brodie for his various communications on the Keuper of
Warwickshire. The specimens found by him and by Mr. Richards
wcro obscure impressions of lamellibranch shells, three of which he
(the speaker) hud selected for detailed description. The discovery
of true marino fossils in the Shrewley Keuper was of the utmost
importance, and the Author therefore deserved the thanks of
geologists.
1 Quart. Journ. Geol. Sue. vol. xlix. ( 18M) p. 171. 2 Gcol. Mag. 1883, p. 557.
Digitized by Google
Vol 50.]
THE OSSIFEROUS FISSURES NEAR IORTHAM
171
14. The Ossiferous Fissures in the Valley of the SnonE, near
Ightiiam, Kent. By W. J. Lewis Abbott, Esq., F.U.S. (Head
January 24th, 18U4.)
CONTENTS. pHgfl
I. Introduction 171
II. Figure* in the South-east of Ktiglund : Ilistory of
the Shod© Valley 172
III. Description of the Fissures near Ightlmm 177
IV. The Fossil Plants and Invertebrata found in the
Fissure 181
V. Conclusions 185
I. Introduction.
Doubtless there arc many geologists in common with myself who
have recognized the fact that, it' the surface of the Wealden urea has
been subject to the oscillations claimed for it, then, considering the
unyielding nature of the lime- and sandstones, we ought to find in-
numerable fissures, and by the law of chances these ought sometinios
to occur in positions favourable to the preservation of those hetero-
geneous collections of objects that find their way iuto the drainers of
a country. There are few, perhaps, who realize what a motley group
of curiosities are to be found in large streams, unless they have spent
some considerable time in walking between the tide-marks of a river
in its lower reaches. It is not often conceived how large a portion of
the life of to-day could be rescued from such a wreck. Hero may be
found bones of animals by the cartload, and the hard parts and fruit
of vegetation, both terrestrial and aquatic. The principal non-marino
mollusca are also represented, although the majority of shells are
usually of aquatic species. To appreciate the profusion of these
relics one need only travel for the same period over land-surfaces and
note the difference of the result. I have frequently paced scores of
miles over fields, foot by foot, chiefly in search of implements, with-
out finding a single bone of an animal of either terrestrial or aquatic
habits.
It is extremely important to bear these two conditions in mind
when we try to account for the filling of fissures and caves with
the materials that we now find in them. I have thought it
absolutely necessary to draw attention to these important facts,
because I regret that 1 am obliged to differ in opiuion from so
great an authority as Prof. Prestwich as to the manner in which
caves and fissures have been filled. The successive faunas of tho
various strata, their stalagmitic sealing-down, the identity of the
contents of fissures with river-debris, and their total dissimilarity
to ordinary land-wash, together with other collateral characteristic
features, to my mind render these deposits incapable of being the
result of a marine immersion.
Unfortunately, the literature of the Weald would not encourage
N 2
Digitized by LiOOQle
172 MR. W. J. LEWIS ABBOTT ON THE [May 1 894,
one to expect very much from the Kentish fissures ; it is true that
references to the ossiferous * pipes ' date as far back as the classic
days of Buckland,1 but from his time to that of Prof. Boyd Dawkins
only 7 species of vertebrates have been recorded, and 5 species of
mollusca. I have visited a number of these pipes in the neighbour-
hood of Maidstone and the Shode Valley, and have no hesitation
in saying that they are altogether of a different nature from the
fissures which will be described in the following pages. The former
are surface-deposits, pure and simple, irrespective of the various
depths and extensions to which they have cut into the underlying
strata, bones and implements being distributed through them exactly
as in an ordinary brick-earth.
II. Fissures in the South-east op England :
History ok the Shode Vallei.
Fissures abound in the hard strata of the Wealden district8 from
the North to the South Downs inclusive ; at times they are mere empty
cracks, never having been brought into direct contact with either the
surface itself or even surface-waters. At others they open more or
less distinctly above, sufficiently to admit of being filled with land-
wash or blown sand ; or a river gets access to them and carries in and
deposits its suspended material, or its flotsam and jetsam. Again,
they are occasionally wide enough to admit of human habitation, some
now containing tons of the relics of human occupation, terminating
in the midden period. There are yet others which, so far as wo
can see, have never been open at the surface : their presence has only
been revealed by the denuding action of rivers in excavating their
channels into the rocks in which the fissures have existed, and, after
having thus broken into their secret chambers, the rivers have depo-
sited within them those heterogeneous masses characteristic of the
burdens of a stream. At times situation has favoured an entire fill-
ing of the fissures ; at others the height to which they are filled
marks the limit of the power of the flood- waters at a particular period
in the valley's history, leaving an empty chamber above. Into this
latter meteoric waters subsequently enter, which, percolating through
the limestone and hassock, dissolve out part of the lime, not only of
the rocks, but of the bones, and redeposit it all over the chamber
and for a certain distance into the fissure-deposit, in the various forms
of arragonito, flos ferri, stalagmite, and stalactite, until at last the
contents of the fissure become sealed down. In some other cases,
1 These pipes are described by W. Topley, F.R.S., in his memoir on 'The
Geology of the Weald,' 187.r), pp. 181-1&4. That author also gives copious
bibliographic references to the subject, to which the reader is hereby referred
in order to save repetition.
9 I unsuccessfully worked a number of these before I located those here
described, but upon enquiry I found that Mr. B. Harrison had already obtained
bones from the latter, which he very kindly passed on to me, giving me at the
same time an introduction to the quarry-owner. The latter has also taken
great interest in my work, and kindly allowed his men to wheel away the debris
for me, a service for which I am greatly indebted to him.
d by Google
Vol. So.]
OSSIFEROUS FISSURES NKAR IG II I'll AM.
173
where the fissures appear to have maintained a free surface-commu-
nication through practically the whole of their history, very nearly
all the bones are dissolved out, and the lime is rede posited in the
interstices of the filling and the adjacent rocks, like veins in ser-
pentine.
The description of the fissures near Ightham may be taken as a
supplement or continuation of the paper by Prof. Prestwich on the
drifts around that place.1 It will, therefore, be unnecessary to re-
capitulate the description of the Shode,3 upon whoso banks those
fissures occur ; suffice to say that the stream now rises on the lower
part of the face of tho Chalk escarpment, about 1£ mile above
Ightham, and after Bowing over the Folkestone Beds in a general
southerly direction, and receiving a westward branch, pierces the
Hythe Beds in a picturesque gorge about 80 feet deep. It then
winds round more to tho east, and in about a quarter of a mile
receives a tributary coming down from the N.E., past Borough
Green. This latter stream has also carved out a deep valley, which,
in wet weather, still carries water. A road has been cut into and
along the old valley, exposing the old sandy brick-earth, the com-
position of which is very significant, owing to its similarity to the
fissure-deposit. It also carries boulders of Ightham stone, chert,
flint, and a few bones and other fossils.
In about anothor quarter of a mile the Shode receives a second
branch from the N.E., thus leaving the area botween the two
tributaries as a promontory, which, by the approach of the two
streams to each other and the rise of the Greensand escarpment or
counterscarp, is more completely isolated. In this the fissures now
to be described occur. The Shode then continues its southerly
course through the Plaxtol gap till it joins tho Medway. Prof.
Prestwich, in his graphic description of this river,3 gives a map and
four transverse sections, which are indispensable in the study of
this district. But to fully understand the exact condition of things,
attention had better first be centred on a section (see fig. l,p.l74)from
the Chalk escarpment up the counterscarp to Shingle Hill. Here we
see the Gault, estimated at 150 to 200 feet,* rising up from below
the Chalk on the lower part of the face of the escarpment, stretch-
ing over and forming the low part of tho Holmesdale Valley ; from
beneath this rise the Folkestone Beds, about 110 feet5 thick ; these
follow up the dip-slope of the counterscarp till they reach Bitchet
1 Quart. Journ. Geol. Soe. vol. xlr. (1889) pp. 270-204.
3 Mr. Topley call* this at renin the Pkxtole brook, op. supra cit. pp. 185, 289.
About Plaxtol it is culled the Bourne.
3 Op, supra cit. pi. ix. & p. 272.
4 In * The Water-bearing Strata of London,' p. 90, Prof. Prestwich refer* to
a well at Wrothatn which gave 120 feet uf Gault. Mr. Topley informs me that
the thickness of the Oault in thia district is greater than was formerly supposed.
A well at Shoreham Place gare 22<> feet. He estimates the clay in the line of
section nt a little over 200 feet.
* These figures and measurements are all estimated from sections in the
neighbourhood and from the table given by Mr. Topley in bis Wealden memoir,
plate iii.
Digitized by LiOOQle
Digitized by Google
Digitized by Google
17*5
MR. W. J. LEWIS ABBOTT OS THE
[May 1894,
Green, by which time their upturned edges are cut through, thus
exposing the underlying Hythe Beds, estimated not to exceed
100 feet. The latter are also much denuded, and a few hundred
yards east of the section are cut through to the underlying Ather-
field Clay, the thickness of which is estimated at 27 feet. Both the
last-named beds appear on the face of the escarpment, where the
Atherficld Clay is underlain by the Weald Clay.
The altitude at which the Shode now rises is 400 feet, and its level
at Plaxtol is about 150 feet, the high ground on the summit of the
banks of the valley at 8hiugle Hill being 550 feet higher : conse-
quently, allowing the full thickness, 127 feet, for the Hythe Beds
and Atherficld Clay, the stream ought to tiow for the most part in the
Weald Clay, and by the time it reaches Plaxtol it ought to have high
clay-banks, exposing 423 feet of Wealden Beds. Such, however, is by
no means the case. Fig. 2 (p. 174) shows a section from Shingle Hill,
through Plaxtol to Hurst Wood, between figs. 8 and 4 of Prof. Prest-
wich.1 Here the stream is seen, at 150 feet O.D., to have only just
entered the Weald Clay, and one also notices that the high towering
sides of its valley are composed almost entirely of ' Kentish Rag/
which extends to an altitude of 700 feet, although the deposit is
only 100 feet thick. Moreover the Mote stream is seen to cut quite
through the Hythe Beds at an altitude of nearly 400 feet, thus
showing that the valley, instead of being one of simple erosion, is
for the most part one of depression .
If we take a section along the Shode Valley (see fig. 3, p. 1 75) we
find that such a depression really has taken place, approximately,
from Plaxtol in a N.N.W. direction to below St. Clare. To this
depression the yielding Gault Clay lent itself by forward progression,
at right angles to the depression, by which the outcrop of the Gault
is nearly doubled in width, as shown in the Geological Survey map
of the district (Sheet 0). The Folkestone Beds, when made up of loose
sand, also lent themselves to the stretch, but when more compact
they cracked ; the limestones of the Hythe Beds, on the other hand,
became very much fissured.
For the purposes of this paper it is not necessary to enter
further into the earlier geological history of the valley ; of this, with
the anthropological succession in the district, I hope to treat fully
on another occasion. The exact date at which the depression took
place has little, if any, chronometric value in connexion with the
contents of the fissure: whether it was in the early stage of the
Holmesdale Valley, when the Bag had 250 feet of Gault and Folke-
stone Beds above it, or whether it was after the river had actually
pierced the former beds, is uncertain. One time-recorder remains,
and that is, the amount bv which the river has lowered its channel
since its debris-charged waters first gained egress into the fissures,
till the time when they were no longer able to do so.
An examination of the existing features of the surrounding
country indicates that the Shode when it first entered the Hythe
1 Op. tupra cit. p. 272.
Digitized by LiOOQle
Vol. 50.]
OSSIFEROUS FISSURES NEAK IOIITHAM
177
Bods, — or very shortly afterwards, — was flowing from N. to 8. as
now. Having previously cut through the Folkestone Beds it
gained access to the fissures, and began to deposit its sediment in
them ; and it continued to do so duriog the whole period that its
waters could carry materials into an unfilled space. Since this
work of filling commenced, the river has cut its bed through about
85 to 90 feet of solid 1 rag ' at this spot. But deepening doubtless
went on long after flood-waters reached for the last time the
altitude of 300 feet, which was about the limit at which the fissures
stopped rilling.
Although there are numerous fissures in the Shode Valley, I shall
confine myself to those on the western side of the promontory pre-
viously described. Here a quarry has been worked and a face 80 feet
high exposed : the direction of the working is a little W. of N. by
a little E. of S., thus revealing the fissures as seen in fig. 4, p. 178.
The strike of these is practically at right angles to the direction of
the downthrow of the valley. They are entirely in the Hythe Beds,
which at this place consist of layers of exceptionally hard, slightly
sandy, crystalline limestone — the Kentish Rag — alternating with
friable, though often somewhat tough, beds of hassock ; the thick-
ness of the layers being from 1 to 2 feet for the rag, and 2 k to
previously demonstrated, the beds are brought from a northerly dip
to a horizontal position. There is a slight downthrow of about
18 inches to the south, the mass between b and c forming a
miniature trough fault — a feature characteristic of the kind of
earth-movement here undergone, the overlying hassock bending
over and thickening in accommodating itself to the new conditions.
A little farther down the valley the limestones are shown with a
decided reversed dip.
The beds at the top have been very much altered, weathered,
broken up, and decomposed for about 4 or 5 feet, and trailed
down in the direction of the fall of the surface. It is still visible
how the upper parts of fissures a and d have been bent and trailed
down the hill ; d towards the Shode, and a into the valley of the
tributary. As these two fissures, and also <•, had obviously been in
contact with the surface, I confined my attention chiefly to b ; of
this fig. 5 (p. 179) is a generalized vertical section. The width of
this fissure is from 1 \ to 5 feet : when I first saw it, it did not reach
the surface by about 4 feet ; there was a ceiling of stalagmite about
12 inches thick ; flocculent lime has also been redeposited into the
cracks, crevices, and interstices of the grains of the adjacent rocks
(shown in the figure by the wavy lines). Below the ceiling was an
empty chamber (b) some 4 or 5 feet in height; the walls and floor
were covered by a continuous deposit of lime, chiefly in the form of
flos ferri at the sides ; while white, with a slightly yellowish-brown
tinge, granular stalagmite covered the bottom, some 3 or 4 inches
III. Description of the Fissures near Ightham.
3J feet for the hassock.
by Google
Digitized by Google
Vol. 50.] TITE OSSIFEROUS FISSURES NEAR 10HTII AM. 179
thick. Occasionally tho stalagmites were crystalline. There was
also a beautiful variety of arragonite, whiter ami finer than the
finest cotton-wool. The third inset, made by the quarrymen,
that I saw, was about So yards from the present representative of
the old stream, and showed the height of the fissure to be rapidly
diminishing, and the top bending down in an arch, so that the two
sides met the top in an angle, and the arragonite chamt»er formed a
enl~i(r-%ac. The deposition of tlocculent lime extended ~> or (J feet
Fig. 5. — Generalized vertical section along JUttnre b.
[Tho dotted line shows t tie present face of the quarry]
into the underlying fissure-material, from which it appeared that the
meteoric waters, which entered the chamber above, acted upon the
fissure-earth, dissolved out the lime from both rock and bones, and
redc|>osited it: tho occurrence of bones increasing as the secondary
dejiosition decreased. Owing to the decrease in the height of the
fissure, this deposit quite sealed down all that was below it. Below
this, towards the back, the fissure-material <i (fig. ">) was more
Digitized by Google
180
MR. W. J. LEWIS ABBOTT OK THE
[May 1894,
friable and loose, presenting a washed-out appearance, probably due
to the inability of the water-power to carry thus far anything but
the lighter materials. The chamber-floor was about 300* feet O.D.,
and from this to the bottom of the working (which was only a very
few feet from the present water-line or clay) it was full of a
deposit (c, fig. 5) which might be described as an ordinary brick-
earth, similar to that exposed in the valley, with the addition of
lime and other materials of the mother-rock, not only of the friable
hassock, but of blocks of rag varying in weight from a few ounces
to nearly half a ton. These blocks (/) occur at all levels through-
out the "deposit, large ones frequently being tightly wedged in, and
impossible to move without blasting. There are frequent boulders
of Oldbury stone and chert, and occasionally a flint, the latter some-
times in the form of flakes ; but up to the present no implements
have been discovered in the fissure. The field (7) above was pro-
bably an encampment in Neolithic times, as neoliths occur in large
numbers on the surface. One of the higher gravels was deposited
upon the Folkestone Beds above the fissure ; remains of the former
still exist on the higher part of the field. There is also a patch of
bleached white flint-gravel about 100 yards square, which I havo
just been able to truce home. These gmivels were worked by
Neolithic man, as often were similar deposits, but I have found
no trace of man in the fissure — except a stray flint or two — and
not a single neolith ! The latter fact is very important in deciding
whether the fissure has been reopened in more recent times than
the period generally associated with Rhinoceros, EUphas, Hya>nay
etc., or even whether it ever did open upon the surface. It is certain
that in the early history of the filling of the fissure gravel covered
tho ground above it, but I have been unable to find any trace of it,
even when the fissure was excavated to the lowest depths penetrated,
which could only have been a very few feet from the underlying
Atherheld Clay. On the other hand, the upper part of fissure d
is full of a breccia similar to that seen on the surface at g.
In places horizontal stratification was very distinct, fine layers of
clay alternating with more sandy ones ; but whether this was due
to original stratification, or to the subsequent circulation of under-
ground waterR I should not like to say ; a fissure a little lower
down the valley still gives out water. In many places there were
evidences of the levels at which the water stood at a particular
time, by the adhesion in great profusion of calcified stems of Chara
in a horizontal line upon the sides of the walls. The delicate scales
of the slow-worm (Aivju\a f myitis) were also found adheriug to the
sides of the fissure for a distance of 20 feet, quite horizontally.1
Very frequently on the stream side of a big block there would be
an accumulation of the large bones, and in a similar position a few
years ago a considerable number were found. On tho inner side of
such obstructions, unless cither above or below them, it was useless
to look for anything but the very smallest organic remains. As the
1 These were about 60 feet above the present water-leTel.
Digitized by LiOOQle
Vol. 5o.]
OSSIFEROUS FISSURES NEAR 10HTHAM.
quarry was worked in platforms from the top to the bottom down-
wards, I had a good opportunity of noting these features, which
unmistakably pointed to the introduction of the debris-charged
waters from the side and not from above. Those cases to which
I particularly refer were about 30 feet from the top.
Fig. 6 shows a view from above of one of these 4 keyed blocks/
Fig. 6. — Plan of one of the keyed blocks, seen from ahove.
In this will be seen not only the stoppage of the largo bones, but
the direction of the waters as they deposited their sediment. It
will also be obvious that, since the deposition of ihe fissure-material
around these blocks, the position of the latter in regard to the
former has not been changed. To my mind the wedged-in state of
these blocks is very significant, for had they fallen from above
during the filling of the fissure the deposit would have formed a
bed for them, and so obviated the keying action : and seeing that
after they fell they were covered with fissure-deposit, if the opening
action had been continued after a stone had become keyed, we
should not find a single stone so nipped to-day ; whereas there are
numbers in that condition all through the fissure, thereby showing
that the process of opening was not a continuous one, and that the
fissures have been stationary since their first filling.
IV. The Fossil Plants and Invertebrata found in the Fissure.
In working down the face of the quarry for the first time I kept
all the fossils from the various levels separate, expecting to find a
Cave-like succession ; but on comparing them with my notes taken
while work was progressing I could see nothing to warrant a sepa-
ration either in the state of preservation of the specimens or in the
occurrence of species — a conclusion simultaneously and indepen-
dently arrived at by Mr. E. T. Newton. In some places certain
species were naturally more plentiful than others ; sometimes frog-
bones were more numerous than all the rest of the bones put
together, at others they were in the minority. I have seen a largo
wall of the deposit cleared on one side for a considerable distance,
and throughout its whole extent it was perfectly solid ; it is certain
that water could not have transferred the fossils from one part of
Digitized by v^ooQle
182
MR. W. J. LEWIS AlUtOTT OK THE
[May 1894,
the deposit to another or re-arranged its constituents. Occasionally,
under large stones or in peculiarly situated spaces, the material was
more friahle and loose, or even a space left ; but, so far as I could
see from careful observations dnring nearly three yours (in which
time I handled, sifted, or washed scores of tons of material), I could
see no possibilities of communication from one part of the fissure to
another to any great extent. At the last inset, and as 1 worked tho
fissure farther back, the deposit was far less solid, more carbonaceous,
and showed more cavities, and I quite expect this phase to increase
as one works inwards.
It is the vertebrates, of course, that arc the most important
fossils of the fissure ; but having stated the conditions under which
they were found, I leave their description to far more competent
hands than mine. I might , j>erhap8, remark that many of the hones
are pcat-stuined, as though they had lain upon a peaty river-bunk
before entering the fissure, which colouring they never lost : they
occurred irregularlv all through the fissure in juxtaposition to iho
unstained bones. The sumo remarks apply to the gnawed bones.
In a few instances, in the case of a bat, a vole, a mole, and a
slow-worm, the creature entered tho fissure very nearly or quite
whole, and their bones occurred near each other ; but it was usually
otherwise, the bones being single and isolated.
List op Fossils other than Ykktebratbb.
Plautie.
CoryUm avetlana (nuts). ! Hifpnum prahmyum.
tytereM tvbur (tu-on.s). | Cham.
Insecta.
Ik/us.
(jtiorhyttckut, sp.
Chnj*>jnd<i, Hp.
Von-tUa scabcr.
Ostraccxla.
Candova Candida, Mull.
Mollusca.
Lituax maTimufi, Linn.
Hydina cc/Uiria, Mull.
„ alliariii, Miller.
„ cry.xtallina, Mull.
fuha, M till.
Htlix (Vatula) rotundata, Miill.
„ hizpida. Linn, (ineluding
Jeffrey*' coiuinna).
,, veiiiora/is, Linn.
„ cricctorum, Mull.
Pupa mutcortrm. Linn.
Yertitjo mhiHiisfiima, Hurtiu.
$HCcincn obhvya. Dm p.
Cr/r/ontotna elryam, Mull. (top).
I nio, ep.? (minute fmginents).
Heiix ( Vallonia) ptdchtlla, Mull.
CaeciUoidr* acicu/a. Mull.
Cochli> opa (Zua) lubrica. Mull.
Caryxhium minimum. Mull.
Digitized by Google
Vol. 50.]
OSSIFEROUS FISSURES 5 BAR IOHTOAM.
183
Rkmarks ox the Plants ahd Invertbhrates.
[Plants. — The stems of the Chara wore in a state of calcic casts,
and at first were very puzzling, and thought to be small annelid-
tubes ; but when submitted to W. Carruthcrs, Esq., F.H.S., he at
once recognized their vegetable nature, and referred me to a collec-
tion of specimens in the Natural History Museum of the same
description. Upon submitting them to Air. It. R. Newton, F.G.S.,
he immediately identified them as similar to a large mass of Chart*
from Northampton described in the Geological Magazine for LsfiS,
p. 5G3. On comparison of the specimens from tho fissure with
these, their identity became at once established. In the latter
both nucules and globules are very plentiful in the entangled mass,
but in those from tho fissure I have only once or twice recognized
the spiral structure of a nucule. Upon dissolving some of the stems
under the microscope Mr. E. M. Holmes, F.L.S., revealed sufficient
structure to assign them to Chara and not to Nitella.
Throughout the whole of the deposit nuts in a good state of
preservation occurred. In the case of the acorns, the inside was a
black, spongy, carbonaceous cast, but tho outside ski us were fairly
well preserved. There are other vegetable remains which have not
yet been identified.
At the back of the fissure exposed since tho reading of the present
paper there is far more carbonaceous matter, and I hope to be able
to obtain more plants from it.
Insect*. — Recently I have obtained upwards of a hundred tiny
little globular bodies from *7o to 1 millim. in diameter, usually single,
but occasionally in clusters of three and four, which Mr. C. O.
Waterhouse, F.Z.S., has identified as the galls of C if nip*. To tho
same gentleman 1 am also indebted for identifying the insects. To
Prof. T. Rupert Jones, F.R.S., I am indebted for nuining the
Ostracod.
Mollusca. — Of these the most plentiful species is Ifyalina celhtria,
which occurs all through the deposit; I obtained considerably over
half a pint of specimens. The next in numbers is Hyali.ua aUiaria ;
the whole of these are of a beautiful translucent pearly white,
similar to those in the Portland fissures ; there in not tho slightest
trace of animal matter or coloration in them. The Hclicid® come
next, Helix (Palula) rotundata topping the list, in which species, as
is usually the case in Pleistocene specimens, the colouring is still
visible. The same remarks apply to //. nemoraJi* and Jf. ericttorum.
The latter species was represented by only two or three specimens.
Succinea oh1on<ja1<t wns fairly common, and reached a length of
17 millim. The CycJo*toma was represented by an apical fragment
of a spire. I also obtained several dozen molluscan eggs of various
shapes and sizes, Irom 3 to 5 millim. in their major diameter ; about
half were pierced, but the rest were not, and when broken open
showed no trace of any colouring. These have not yet been
determined.
Vertigo niintttissima calls for special notice, owing to its unusual
Digitized by Google
VK, W. J. LE^I* ABBOTT 09 THF.
:May 1894,
size, reaching a length of 6 millim. This species, I believe, bad not
been discovered in Pleistocene deposit* until I obtained it from the
New Admiralty section,1 associated with Bttuh nana ; in this
deposit also the species attained a similar size, from which it would
appear that the species has greatly dwindled in size since Pleistocene
times. I also found on several occasions small fragments of a pearlv,
flaky shell which I have no doubt is Unio. The Limart* were repre-
sented bv six specimens.
I handed the whole of the shells to Mr. B. B. Woodward, F.G.S.,
with whom I have had the honour of working for many years, with-
out telling him whence they came, and asked him to kindly name and
report upon them. In reply he said: — "Judging by its frequent
occurrence in late Tertiary deposits, Surcinea oblonga was far more
common formerly than it is to-day. Its presence seems to indicate
the proximity of very marshy ground. The V. minutisgimer are
perfect giants! All* the species are living at the present day,
and the state of preservation i* not such as to suggest any great
antiquity."
The best estimate of their age can probably be made from their
comparison with the faunu of a remarkable land-wash which exists
in the neighbourhood. From this latter I obtained some 24 species
belonging to 10 genera, and from the bottom of the deposit Neolithic
flint-flakes, and pottery ; but there are no signs of Succinea ohlonga,
nor is the general facies that of so water-loving an assemblage as
that of the fissure. Still, with the exceptions of the fragments of
Unto in the latter, no truly aquatic forms occur, although all of them
are found in river-deposits elsewhere. In contrasting this lnnd-wash,
which is some 12 feet thick, with the fissure-deposit, I might observe
that it contains scarcely a single bone, thus adding further, in
my opinion, to the improbability of the fissure-deposit being a land-
wash ; while the absence of alhum (jwcum and path-trodden surfaces,
the occurrence of single whole bones, unaccompanied either by
fragments or foreign matter, is prejudicial to the idea of the bones
having been carried in by, or as having made a passage through,
carnivorous beasts or birds. — February 0th, 181)4.] 2
» Proc. Geol. Assoc. toI. xii. (1892) pp. 340-350.
* [The last four species (see list on p. 182) have been added to the tnollusca
since the reading of the paper. Of these, Hdix jmlchella and Cvcilioide* acievta
are represented bv a single specimen ; of Cochticopa /ubrica there is also a single
example, which is immature ; none of these presents any features of special
interest. The two specimens of Carychium minimum, on the other hana, call
for some remarks, as they differ greatly from the type, and would no doubt be
regarded by many as a new species, or at least a new variety. Seeing, however,
that this species varies greatly, both Mr. B. B. Woodward and myself consider
it inadvisable to found either a new species or variety on the material to band.
We have compared it with several hundred Pleistocene and recent examples,
and find the following features and differences In outline it is altogether
more sloi.der than the type ; it is fully 2 (1 mm. in height, its width not exceeding
•7f> mm. The whorls are six in number, more closely coiled, and consequently
longer, and increase more gradually all through, so that the spire is higher and
more tapering. The body-whorl is much less in proportion. The mouth is more
roundea, and not at all constricted at the outer tooth ; on the other hand,
Digitized by LaOOQle
Vol. 50.]
OSSIFEROUS FISSURES NEAR IGHTIIASI.
1S5
V. Conclusions.
It is a little difficult to sum up the questions raised by the
Ightham fissures and their contents until one has read Mr. Newton's
paper. Still I think there are certain points which must be
settled before a correct estimate can be made of the palaeontologies!
significance of these discoveries. They appear to me to be these : —
1. Was the filling up of the fissures effected by (a) a marine
submergence, or even (6) were the contents washed in from a laud-
surface above? or
2. Were the fissures filled by the action of a river from the side ?
3. Was the opening of the fissures a continuous and recurring
one, after the first introduction of fissure- material, and the hereto-
fore recognized Pleistocene mammalia ; thus making the contents
of the fissure belong to any age since the first opening ? or
4. Did the river, when it first entered the fissures, find them of
practically the same width as now ? Was the filling confined to
one period, and therefore the fossils all of one geological age ?
The answers that suggest themselves to me are the following : —
1. (a) The fact that we have raised beaches extending a long
way inland, left as relics of submergence, suggests that, had such an
action taken place in the Ightham neighbourhood, with its land-
locked depressions, some vestiges of it at least- would have been
left; and of all things in the world no traps would have been more
fitted for the purpose than empty fissures. Yet I must admit
that I have been unable to find a single particle of an obviously
marine deposit. On the other hand, the whole of the contents are
of terrestrial origin ; and this, with the detached and gnawed con-
dition of the bones, is to my mind hopelessly fatal to the hypothesis
of a marine submergence.
(b) The description given in the Introduction (p. 171) of the
absence on land-surfaces many miles in extent of the relics found
in the fissures, and the extremely limited area of the little pro-
montory in which the latter occur, dipping on all sides and covered
with materials not found in the fissure, render it imi>ossible for the
filling to have been effected simply from above. We may be sure
that, whatever might have been the agencies by which the Holmesdale
Valley was scooped out, the soft Oault Clay would have given way
before the harder Folkestone Beds (as is evinced by the lie of the
older gravels), so that a northward extension of a gathering land-
surface was truncated. The stream, however, extended over the
Gault, and from this source derived the clay which forms a con-
stituent of the fissure-material, both disseminated and as water-rolled
the tooth itself it almost wanting, and is represented by a mere thickening of
the labrum. The columella-teeth are not more than one- third the size of
those in the recent species, and occur down inside the whorl so as to be in-
visible when the shell is riewed obliquely. The peristome is more reflected and
let* thickened, and consequently loss ' toothy,' altogether presenting more the
outline of Paludeiirina marg ittaia.— March 20th, 1«94.]
Q. J. G. S. No. 19S. ' o
Digitized by LaOOQle
186
MR. W. J. LEWIS ABBOTT ON THE
[May 1894,
pebbles, none of which exists in the sandy beds above the fissure ; and
from the Gault Clay pools were derived in times of flood the large
(quantity of CAara-stems. It thus appears impossible for the filling
in to have resulted from marine submergence, or for the material
to have been introduced in the form of a land-wash from above.
2. That the deposit was introduced into the fissures by a river is
to my mind evident, from the fact that the material itself is exactly
similar to that deposited in other sequestered spots in the valley,
and the additional fossils constitute just such a heterogeneous mass
as is to be found in the burdens of a river when preserved, and
nowhere else. That water was present during deposition appears
evident from the horizontal stratification of the sand and clay, and
the scales of slow-worm and Chara- stems adhering in a straight line
along the walls of the fissure ; while the manner in which the
fissure-material was forced upwards into blind veins and crevices
from below is explicable on no other than an aqueous hypothesis.
That the river was entering at the sides of the valley during a long
period in the history of the filling of the fissure is absolutely certain
from the damming action of the keyed stones, and the deposition of
the material in passing round such large blocks.1
Coming to the mollusca, Helices, Pupa, and the others are always
found in river- deposits, and such forms as Succinea are never found
far from water, but usually in it, while Unio is never found
else where. The preponderance of frog- bones over everything else,
the large number of water- and bank-voles, the presence of Chara
in such profusion, entomostraca, and Triton unmistakably point, in
my opinion, to the fissure-deposit having had a river origin.
3 and 4. In the keyed stones, as it appears to me, we have an
absolute answer to the question of the reopening of the fissures.
"We have seen that the keyed stones occur all through the deposit,
into which position they were let fall, by the Assuring of the strata
(or some may have been dislodged from the mother-rock by the
entering of the water during the process of filling). It was in this
keyed condition that they were when the deposit successively reached
them. As the fissure filled the material became packed closely all
round and over them, the inward transport of larger burdens being
intercepted by these obstacles ; and just as the material was originally
deposited, so we find it to-day. Had a subsequent widening set in
every stone originally keyed would have been loosened from the
grip, and a keyed stone would have been practically an impossibility.
It might, however, be urged that, by an unprecedented series of
coincidences, every stone was so placed that when its hold was
broken it ploughed through the solid material until it again became
keyed, or fresh ones got into that condition. But if this were the
case, and the stones moved out of their original position, all former
1 Very careful and protracted observations lead me to consider that the
downthrow of the Talley did not occur till just immediately after the ruer bad
entered the Hythe Beds.
Digitized by LiOOQle
Vol. 50.]
OSSIFEROUS FI8SUKES NEAR IOUTUAM.
187
relations of stratification and filtration would have been obliterated ;
this, however, we know was not the case.
Attention might also bo called to the fact that the bank on the
top of the fissures became an old Neolithic settlement, neoliths
being scattered over the surface literally in hundreds, yet not one
of these was found in the fiasure.
It is true that the mollusca might have borne a more aquatic
facies, and not much can bo said from a solitary entomostracon,
but I have worked for many months at a river-deposit in which
there were myriads of these little creatures, and only found one
gosteropod, nor do any of the more aquatic forms occur in any
deposit which I have worked in the valley outside.
We have, however, I think, fur more evidence both positive and
negative than we could reasonably have expected under the cir-
cumstances, that the fissures have never been reopened since they
were first closed by the materials introduced into them by the river ;
and although it is within the bounds of possibility that in somo
unknown and incomprehensible manner some stray modern relic has
been introduced, and in each case by some remarkable modification
of chemical laws has been changed into a condition indistinguishable
from those upon which the same forces have been operating for
couutlesa ages, there is still the great balance of probabilities that
the whole of the contained fossils belong to one and the samo
geological period.
I am fully aware that there aro many remains found here which
have not been found before in recognised Pleistocene deposits ; but
that has been my experience with other sections at which I have
worked for a long time. The increase in species is only such as to
support the suggestions made by Mr. Clement Reid in connexion
with the Forest Bed fauna,1 namely, that late discoveries tend to
show that it is the larger Pleistocene mammalia that have becomo
extinct, and that the more we discover of tho smaller creatures of
this age, the more they approximate to those of our own time.
Even if we were to exclude from the lists all the species not
previously found fossil elsewhere, we still have an extensive
assemblage of the older Pleistocene forms which must have lived
during the filling of the fissure : this therefore limits the filling
operation to Pleistocene times.
In conclusion I have to express my hearty thanks to the officers
of the Geological Survey, especially Messrs. Clement Reid, H. B.
Woodward, and W. Topley, for the very great assistance which I
have received from their invaluable advice, while it is unnecessary
to remark that the chief value of the paper hinges upon the work
bestowed by Mr. E. T. Newton upon the vertebrates. I have also
to thank Mr. B. B. Woodward for his kind assistance in the deter-
mination of the mollusca, and Mr. C. 0. Waterhouse for naming
the insects.
[For the Discussion on this paper, see p. 210.]
• Mem. Qeol. Surv. 1890, 'The Pliocene Depo.ita of Britain,' p. 182.
o2
188 MB. E. T. NEWTON ON THE VERTEBRATE [May 1 894,
15. The Vertebrate Fauna collected by Mr. Lewis Abbott from
the Fissure near Ightham, Kent. By E. T. Nkwton, Esq.,
F.R.S., F.G.S. (Read January 24th, 1894.)
[Plates X.-XIL]
I. Introduction 188
II. Review of the Species.
Amphibia 189
Beptilia 190
Avee 191
Mammalia.. 192
III. Table of Distribution of the Vertebrata found in the Ighthara Fiseure, 203
IV. Conclusions 204
I. Introduction.
The remains of vertebrate animals collected during the last two or
three years, with much care and in large numhers, by Mr. Lewis
Abbott, from ono of the fissures in the Kentish Rag near Ightham,
in Kent, have been from time to time brought to me for exami-
nation and identification. The outcome of this Btudy of many
hundreds of specimens is contained in the present paper.
The occurrence of Pleistocene mammalian remains in Kent is
well known, and Mr. W. Toploy 1 has noticed such remains in the
brick-earth filling long chasms in the Kentish Rag, which he alludes
to as 4 Pipes/ varying much in size and very numerous in the neigh-
bourhood of Maidstone. In one Buch chasm at Boughton, 3 miles
south of Maidstone, numerous bones were found by Mr. Braddick
many years ago, and Dr. Buckland* was of opinion that these
ossiferous cavities were 4 caverns.' So far as I have been able to
ascertain, this is the only recorded instance of mammalian remains
being found in what appear to be caves or fissures in the Wealden
area. The species found at Boughton are enumerated by Prof. Boyd
Dawkins • in his paper on the 4 Distribution of the British Post-
Glacial Mammals,' namely, Jfyrrna spelfm [=//. crorvta\ Cervus
tarandxis, C. ela pints, Bos primitjcnius, Equus caballus. Rhinoceros
fulwrhinus, and EUphas primujenius ; all these species, with the
exception of Bos primifjenius, have been found in the Ightham
fissure. The larger fossil mammalia of the South-east of England
have received much attention at the hands of many investigators,
and several valuable collections have been made, chiefly from the
Thames Valley, notably that of Sir Antonio Brady, now in the
British Museum, that of Dr. Cotton, preserved in the Museum of
Practical Geology, and that brought together by Dr. Spurrell, of
1 4 Geology of the Weald/ Mem. Geol. Suit. 1875, p. 179.
8 Phil. Mag. ser. 2, toI. ii. (1827) p. 73.
» Quart. Journ. Geol. Soc. toI. xxv. (1869) p. 192.
Digitized by Google
Vol. 50.]
T.KVSA FROM TIIE IGHTHAM FISSURE.
189
Belvedere, and more recently by his son, Mr. F. C. J. Spurrell,
which has lately been presented to the National Collections by
the last-named gentleman. Although so much has been achieved
for the larger Pleistocene mammalia, little or nothing was done,
until the last few years, in the way of collecting the smaller
vertebrates of these deposits. The admirable results obtained in this
direction by Dr. Blaekmore 1 and Mr. W. A. Sanford " in the West of
England, and by Mr. Clement Reid * in the Norfolk Forest Bed, by
means of careful washing, led me to suggest to several friends the
desirability of collecting in the same manner the small vertebrates
of the South-east of England. Something has already been done by
Mr. It. \V. Cheadle and by Mr. F. C. J. Spurrell4; and the mag-
nificent series now exhibited is, with very few exceptions, the result
of enthusiastic collecting by Mr. Lewis Abbott, who was the first to
recognize the importance of the remains from this fissure, although
a few specimens had previously been obtained by Mr. B. Harrison,
of Ightham, whose collection of rude implements from the higher-
level gravels of that neighbourhood is well known. The small
bones from this fissurs, when first found, were very friable, but are
now, after Mr. Abbott's careful preparation with gelatine, in an
admirable state of preservation ; they represent mammals, birds,
reptiles, and amphibians ; but no fishes have been met with,
although their remains have been diligently sought for.
I am under obligation to the officers of the British Museum
and of the Royal College of Surgeons for the facilities afforded to
me when working at the osteological collections under their charge.
The Hunterian Museum series in the latter institution was found
especially advantageous for the comparison of this largo and varied
series of fossils.
The remains of each species will now be passed in review, and,
finally, some remarks will be made on the conditions under which
they have been accumulated, and their relation to the Pleistocene
faunas of other localities.
II. Review op the SrEciss.
Amphibia.
Rana temporaria. (Common Frog.) PI. X. figs. 1-3. — The re-
mains of frogs in this fissure are far more numerous than those of
any other animal. Nearly the whole of them are referable to the
common species R. Umporaria, and they includo, together with
nearly all other parts of the skeleton, the characteristic male
humerus with its strong, backwardly directed ridges, the biconcave
penultimate vertebra and proecelous sacrum, the comparatively
1 See • Flint Chip*/ by Edw. T. Stevens, 8ro, London, 1870 ; alao Blackmore
and Alston, Proc. Zool. Soc 1874, p. 400.
2 Quart. Journ. Geol. Soc. to), xxvi. (1870) p. 124.
3 Mem. Geol. Suit., VertebraU of the Forest Bed Series (1882).
« Geol. Mag. 1890, p. 452.
Digitized by Google
190 MB. E. T. IfEWTON 05 THE YEBTEBRATB [May 1894,
narrow ilium with its elongated tubercle above and well in front of
the acetabulum, and parts of upper jaws with teeth. Rana tempo-
raria has been found in the Forest Bed ; it is now living in Northern
and temperate Asia, as well as in Europe and Great Britain ; in
mountainous regions it occurs up to a height of 10,000 feet.1
Bufo vulgaris. (Toad.) PI. X. fig. 4. — Among the many batra-
chian ilia, most of which have been referred to Rana temporaria, I
have found five or six which, besides being more slender even than in
the common frog, have a rounded tubercle just above the acetabulum ;
and, as these are among the characters which distinguish the skeleton
of the toad from that of the frog, I have included these six ilia in
the above species. Bufo vulgaris has been found in the Forest Bed ;
it is now living in Europe, Asia, and North-west Africa, as well as
in Great Britain ; its vertical range extends to 7000 feet.
Molga.Bjt. (= Triton). (Newt.) — Five small vertebra and part
of a skull, I have no doubt, belong to this genus, but the species is
uncertain.
Repttlia.
Anguigfragilis. (Slow-worm.) PI. X. figs. 5-7. — The remarkable
ornamented and widely-bordered bony scales, by which this limbless
lizard is completely encased, have been found in somo numbers,
together with vertebra?, parts of skulls, and lower jaws. There can
be no doubt as to the identification of this form. Arujuis fragilis
is living throughout Europe, including Britain, but excepting the
most northerly parts of Russia and Sweden ; it has been met with
as high as 7000 feet, and occurs also in Western Asia and Algeria.
Tropidonotus natrix. (Common Snake.) — About a dozen ver-
tebra?, which agree with those of the common snake, are referred to
this species, which has been recorded from the Forest Bed. It is
now living in most parts of Europe, including Great Britain, from
latitudes of about 58°, southward to Italy, as well as in Western
and Central Asia and Algeria. It is known to range upwards to
5000 feet.
Vipera (Pelias) berus. (Viper.) PI. X. figs. 8, 9.— The hinder
two-thirds of a mandibular ramus is referred to this species ; it agra s
with the corresponding part of the viper in being anteriorly slender
and rounded, deep in the coronoid region, and strongly curved from
end to end. The common snake has the ramus of the lower jaw less
curved, stouter throughout, and not specially deep in the coronoid
region. Although the evidence is slight, there can bo no doubt as
to the correctness of this reference. The viper is now living through-
out Europe from Northern Russia to the South of Spain and Italy,
including Great Britain, but not Ireland ; in mountain-ranges it is
said to ascend to 9000 feet.
1 I am indebted to Mr. G. A. Boulenper, of the British Miwum, for the infor-
mation regarding the vertical range of the amphibia aud reptile*.
Digitized by Google
Vol. 50.]
FAUSA PROM THE rOHTHAM FISSURE.
101
Aves.
The remains of Birds in this fissure are comparatively rare, and,
although some eight different forms have been recognized, only one
or two of them can be said to have been satisfactorily determined ;
they have been carefully compared with a number of recent skeletons,
and the names given below are believed to be correct, but the small
passerine birds are, in many cases, so much alike in their osteology,
that it is difficult to distinguish their bones, and the want of
skeletons for comparison prevents some of the other remains from
being definitely named. All the forms of birds alluded to in this
paper have a wide distribution, being found throughout the greater
part of Europe and Asia, extending northward to or beyond the
Arctic Circle, and southward to Northern Africa.
Turdas miisiciu ? (Song-Thrush.) — The proximal half of a
humerus, somewhat stouter than that of a lark and agreeing with
that of a song-thrush, is all that can be referred to this species.
Scuvicola (Enanthe? (Wheatear.) PI. X. figs. 13, 14. — A humerus
aud two metacarpals are provisionally placed in this species.
Motadlla? (Wagtail.) — Two ulnae seem to belong to either the
pied or the white wagtail.
Anthus prattntii ? (Meadow-Pipit or Titlark.) — A single cora-
coid seems to agree most nearly with this species.
Alauda arvenais. (Skylark.) PI. X. figs. 10-12. — A humerus
and three metacarpals are referred to this species. The same bones
of the song-thrush are very similar in form and size to those of the
skylark, but the humerus of the former is a trifle stouter, and the
united metacarpals have a shorter opening left between them than
they have in the latter. With these bones are associated a part of
a tibia and two metatarsals. Two recent skeletons of this species
which I have in my possession differ markedly in size, especially
as regards their metatarsals ; and the two fossil examples of this
bone differ in a similar manner.
Buteo ? (Buzzard?) PI. X. fig. 18.— The greater part of a tarso-
metatarsus of a large raptorial bird I am unable at present to
identify with certainty. In general form it is like that of the
common buzzard, though it is not only larger, but has the proximal
part broader. Most probably it will prove to belong to the
somewhat largor Buteo lagopu*, but I have been unable to obtain a
skeleton of that species for comparison.
Anns boseas ? (Duck.) PI. X. figs. 1 6, 1 7. — Two humeri agreeing
very closely with the same bones of the common duck are provi-
sionally placed in this species ; and with them are associated for the
present two ulnae, which, being rather too large proportionately for
the humeri, may represent another species. Three other fragments
Digitized by Google
192
MR. E. T. NEWTON ON TOE VERTEBRATE
[May 1894,
are also included here. This species has been recorded from the
Pleistocene of Fisherton, and possibly from other deposits of similar
age, as well as from the Forest Bed."
Lams? (Gull.) PI. X. rig. 15. — The distal half of a humerus
closely resembling that of a gull or tern is provihionally placed in this
genus ; but at present I have seen no skeleton with which it exactly
agrees.
Mammalia.
Insectivora.
Talpa europwa. (Mole.) — Remains of the common mole are
plentiful in this fissure, and iucludc bones from nearly every part
of the skeleton. Although it may bo questioned whether these
remains are contemporaneous with the extinct forms, yet, as the
mole occurs in the Forest Bed, there is no reason for doubting its
occurrence in the Pleistocene. It is living throughout temperate
Europe and Siberia ; and, although found in Britain, except in the
northern parts of Scotland, is not met with in Ireland.
Sorex vulgaris. (Common Shrew.) PI. XI. fig. 1. — Portions of
several skulls and lower jaws, with teeth, as well as other parts of the
skeleton, which agree precisely with the recent form, undoubtedly
belong to this Bpecies, which has already been found fossil in the
Forest Bed and in Caves. Sorex vulgaris is now living throughout
Middle and Northern Europe, as well as in Britain, and extends in
Russia to the 00° of north latitude. In the Alps it is met with
up to heights of 6000 feet.
Sortx pygrmnts. (Pigmy Shrew.) PI. XI. fig. 2. — Three adult
skulls and some perfect mandibular rami, with teeth similar to those
of S. vulgaris, but much smaller, are referred to this species. S. pug-
mmts has been recorded from the Forest Bed. It is now living in
Northern Asia and in Northern Africa, as well as iu nearly every
part of Europe, including Great Britain.
Cheiroptera.
TespertiUo Nattereri. (Reddish-grey Bat.) PI. XI. fig. 3. — The
remains of bats are very numerous, but the greater number of
them are referable to this species. Parts of several skulls and
many mandibular rami, some of which have all the teeth iu place,
present the characteristic dentition of the genus, namely j, ?, ? ;
they agree in Bize with this species, and the anterior cheek-teeth
have similar proportions to each other, thus leaving little room for
doubt as to the correctness of the determination. Femora, humeri,
ulna?, etc., of corresponding size are also associated with the skulls in
this species. V. A'attereri is now living throughout Middle, and in
some parts of Northern Europe, as well as in Britain.
Digitized by LiOOQle
Vol. 50.]
FAUNA FROM THE IGHT1IAM FISSURE.
193
Vespertilio ? — Several humeri, and a femur representing a bat
intermediate in size between the pipistrclla and long-eared bate,
are provisionally placed in the genus Vespertilio.
Scotophilus pipistrellus ? (Pipistrella.) — Two small femora and
two ulna?, which agree in size with those of S. pipistrellus, arc
provisionally so named. This species is now living in Jiiddle and
Northern Asia as far eastward as Japan, also throughout Europe
and Britain as far north as u'U°.
Plecotus ( Vespertilio) auritus ? (Long-eared Bat.) — A femur,
several humeri, and uln®, which in size agree with those bones of
P. auritus, as well as two lower-jaw rami, somewhat smaller than
those of Vespertilio NaUereri, are provisionally referred to this specirs.
It is now living in Europe (including Britain), from Spain and
Italy northward to the 60th degree of uorth latitude in Scaudinavia
and Kussia. In the Alps and the Harz it does not extend higher
than the forest region.
Rodentia.
Lepus timidus. (Hare.) PI. XI. figs. 4-5. — The bones referred to
this species call to mind those from the Somerset Caves, recorded by
Mr. W. A. Sanford,1 which, on account of their larger size, were re-
ferred by him to Lepus diluvianus. It seems very doubtful, however,
whether L. diluvianus is really a distinct species, and Dr. Woldrich '*
suggests that it may be only a variety of L. variabilis. The bones
from the Ightham fissure, although larger and stouter than those of
L. timidus, undoubtedly more nearly resemble the corresponding
parts of that species than they do those of L. variabilis. The ilium
of L. timidus is much broader proportionately than in L. variabilis ;
the Ightham specimen is likewise very broad. The femur of L. timi-
dus, although absolutely shorter than that of the L. variabilis used
for comparison, is stouter in every particular, and has the shaft
flattened from above downward. The femur from the Ightham
fissure, although as lotog as that of L. variabilis, has all the propor-
tions of L. timidus. The humeri and other bones of these two
species bear a similar relation to each other ; and the corresponding
fossil bones, which are referred to the present species, in each case
similarly agree with L. timidus: these include tibia*, humeri, ulnae,
radii, foot-bones, and a pair of lower incisors. Two pieces of ulna3
seem to have a nearer resemblance to L. variabilis, but they are not
sufficient for identification. Lepus timidus has been recorded from
Pleistocene deposits ; it is now living from the north of Bussia to
the south of Spain and Italy, and occurs in the southern parts of
Sweden ; but, although common in England, is not found in
Ireland, where it is replaced by Lepus variabilis. In Scotland
both Bpecies are found.
1 Quart. Journ. Geol. Soc. vol. xxvi. (1870) p. 126.
» 8iuung»b. d. k. Akad. d. Wiwensch. Wien, vol. lxxxii. (1880) p. 11.
Digitized by Google
104
MR. E. T. XEWTOS O.V THE VERTEBRATE
[May 1894,
? L'pus cuniculus. (Rabbit.) — Several portions of tibiae certainly
belong to the common rabbit and to young individuals, but there is
much doubt as to their being contemporaneous with the other
remains with which they are now associated. The burrowing habits
of the rabbit make it probable that these remains belong to a later
period. The rabbit is a South European form, and although now
abundant in many parts of Central Europe and in Britain, is probably
not indigenous to any area north of the Alps.
Lagomys pusUlus. (Pika or Tailless Hare.) PI. XI. fig. 6. —
The left ramus of a lower jaw, wanting the articular process and the
anterior cheek-tooth, leaves no doubt as to the presence of Lagomys
in this fissure. The recent species of the genus exhibit a remarkable
similarity in the pattern of their teeth, and in absolute size there is
less difference than might be expected from the variations in this
respect observable in the skulls and skeletons of the different species.
In size, however, as well as in the length of the entire row of five
cheek-teeth (0*7 millim.), the fossil comes nearest to Lagomys
pusillus. The complex anterior, or penultimate, premolar is wanting,
but the alveolus shows that its grinding surface had a triangular
form. The three intermediate grinders are alike, and each has an
anterior and a posterior prism of dentine, surrounded by enamel,
which are as nearly as possible of the same size ; the last molar is
very small, and consists of a single prism. The remains of La-
gomys, found in British Caves, were referred by Owen to a new
species, L. spehrus, but are now generally included in the species
L. pugillus; and seeing that the jaw from the Ightham fissure
agrees best with the same living form, there is no hesitation
in referring it also to L. pugillus. This species is at the present day
living in the southern districts of the Volga and Ural Mountains,
as well as in Southern Siberia as far east as the Kiver Obi.
Spermophilus. — Portions of six right mandibular rami, the upper
parts of a cranium, parts of two humeri each with an epicondylar
foramen, and parts of four uhue are referred to this genus. Un-
fortunately the parts preserved, including two cheek-teeth, are not
sufficient for specific identification. All these remains seem to be
rather smaller than those from Erith, which have been named
S. erythrogentndfs, but it is quite possible that they may belong to
that species. Spermophilus is not now living in Britain.
Mus sylvaticus. (Long-tailed Field-Mouse.) PI. XI. fig. 7. —
About forty lower-jaw rami and portions of four skulls are referred to
this species. Four of the rami have the anterior check-teeth in place,
and these show the deep longitudinal groove, with an anterior and
two outer accessory cusps similar to those of Mus sylvaticus, except
that the more anterior of the outer accessory cusps is compressed
and apparently more definitely separated from the paired cusps. But
as there is some variation to be seen in this respect in the teeth of
Mus sylvaticus, and sometimes there is even an additional accessor}*
cusp, it would scarcely be justifiable to separate these fossils from
Digitized by LiOOQle
Vol. 50.]
FAUNA FROM THE I9HTHAM FISSURE.
105
the common living species. The largest of these rami measures
about 15*5 miliim. from the point of the incisor tooth to the arti-
cular condyle ; while the three cheek-teeth occupy about 3*6 miliim.
and the front tooth 1*7 miliim. — measurements which agree with
those of M. sylvaticus. One or two front upper cheek-teeth are
preserved, which agree with this species. Mus sylvaticus has been
found in the Forest Bed, is now living in nearly the whole of
temperate Europe as well as in Britain, and is found in Western
Siberia and the Caucasus. In the Alps it extends upward to 0000
feet above the sea.
Mus Abbotti, sp. nov. PI. XI. fig. 8. — Seven mandibular rami
and parts of four skulls, considerably larger than those referred to
M. sylvaticus, it was at first thought might belong to one of the small
species of Cricetus 1 ; but fortunately one of the rami has all the teeth
preserved, and a second has the front cheek-tooth in place ; these
teeth are found to agree with Afua, and not with Cricetus. All the
cheek-teeth are well worn, and the pairs of cusps have united late-
rally, but the longitudinal groove is deep and similar to that in
M. sylvaticus. The front check-tooth wants the anterior accessory
cusp, or has it very small ; in one example it has united with the
anterior pair of cusps, while in another specimen it is so small as
only to be seen with difficulty. The hinder and outer accessory cusp
is as in M. sylvaticus, though the accessory cusp opposite the median
pair is reduced to a compressed and elongated ridge, as in some of
the specimens referred to M. sylvaticus, and like that which obtains
in M. minutus. In M. sylvaticus this same cusp sometimes has a com-
pressed appearance and is little more than a part of the outer cingulura.
The second and third cheek-teeth in the present form are liko those
of M. sylvaticus. Four portions of skulls are provisionally associated
with these lower jaws ; they are without teeth, and are not only
larger than in M. sylvaticus, but have proportionately wider palates,
shorter noses, and broader interorbital spaces. The teeth of this
mouse agree most nearly with those above referred to Mus sylva-
ticus, differing, however, from that species in the absence or slight
development of the anterior accessory cusp of the front lower
cheek-tooth. The length of the best-preserved ramus, from the
point of the incisor to the articular condyle, is 18*8 miliim.; the
entire series of cheek-teeth measures 4*1 miliim., and the anterior
cheek-tooth 1*8 miliim. The only fossil species that need be men-
tioned is the Mus orthodon, Hensel,* the teeth of which, so far as
one may judge from the much-worn examples which are figured,
approximate to the present fossil ; but as the front cheek-tooth
of that species is one third larger than that of the specimens
now being considered, the two cannot well be referred to the same
species. I propose to name this new form Mus Abbotti,
1 See Nehring, 'Ueber Pleistocane Hamster-Rjate,' Jahrb. d. k.-k. geol.
Reichgaiwtalt, vol. xliii. (1&)3) p. 179.
2 Zeitachr. Deutach. geol. Gesellach. vol. riii. (1856) p. 281. See also Dr.
Fumytfa Major, Atti Soc. To«cana di Sci. Nat. Proe. Verb. toI. ir. (188t) p. 1J9.
]f)6
MB. E. T. NEWTON ON THE VERTEBRATE
[May 1894,
Myodes Ummus. (Norwegian Lemming.) PI. XI. fig. 9. — Two
mandibular rami and a single cheek-tooth are all the remains which
can be definitely referred to this species. The front cheek-tooth
has 4 inner and 3 outer angles (or 5 and 4, if the very slight angles
of the small anterior prism be counted), the prisms having the
open lax arrangement distinctive of the Norwegian lemming.
The jaws, when perfect, must have been about the same size as
the largest of those referred below to M. torquatus. AfyocUs Ummus
is known as a Pleistocene species ; at the present day it is living
in the Scandinavian peninsula and in Russian Lapland.
Myodes torquatus. (Arctic Lemming.) PI. XI. fig. 10. — Twelve
mandibular rami, of different sizes, more or less perfect, and for the
most part with their teeth in place, represent this species. These
rami are intermediate in size between Microtus amphibius and
M. ay restis, and the front cheek-tooth has the 5 outer and 6 iuner
auglcs characterist ic of the Arctic lemming. Among the rodent limb-
bones alluded to below several distinct 6izes may be distinguished,
between those which agree best with Microtus ay testis and those re-
ferred to M. amphibius. The largest of them are much smaller than
those of M. amphibius, and may belong to the present species or to
Myodes Ummus ; but on comparison with the skeletons of M. tor-
quatus in the British Museum they are found to be stouter, and the
femora and humeri have distinctly larger heads. Myodes torquatus
occurs in Pleistocene deposits in England and on the Continent,
but is at the present day a purely Arctic animal, living, according
to Coues and Allen, in Arctic America, Greenland, and corresponding
latitudes in the Old World.
Microtus {—Arvicola) ylareolus. (Bnnk-Yolo.) — To this species
arc referred more than a dozen lower-jaw rami, the front cheek-teeth
of which have the characters of SI. ylareolus (4 outer and 5 inner
points). Two of these rami belonged to aged animals, the teeth
being strongly rooted. The smallest of the arvicoliue limb-bones
among these fossils are shorter and stouter than those belonging to
recent examples of this species, and it is possible that some of those
which come near to M. arvalis may belong here. Microtus ylareolus
has been found in the Forest Bed, in Caves, and in Pleistocene
river-deposits ; it is now living in Britain and throughout Europe ;
it extends southward to the Apennines, and northward to within
the Arctic Circle.
Microtus ( = Arvicola) amphibius. (Water- Vole.) — About twenty
lower-jaw rami, very perfect, and several portions of skulls, as well
as many incisor teeth, pelvic bones, femoru, tibite, humeri, ulna?, and
radii, are without any doubt referred to this species— the front
lower cheek-teeth having the characteristic pattern, namely, 5 inner
and 4 outer angles. Microtus amphibius has been found in Pleisto-
cene deposits, and possibly also in the Forest Bed ; it is now living
throughout Europe as well as in Great Britain, and extends east-
ward through Siberia.
Digitized by Google
Vol. 50.]
FA UN* A FROM THE ItinTKAM FISSURE.
107
Microtus ( = Arvicohi) arvalis. (European Field-Vole.)— Portions
of nearly a dozen skulls, mostly rather smaller than those referred
to M. agrestis, are placed in this species. Eight of them havo the
second cheek-tooth preserved, which shows, in each case, only
5 angles ; while some have the hinder cheek-tooth present and
showing 4 inner and 3 outer angles. Several lower-jaw rami are
associated with these skulls ; they are rather smaller than that
referred to M. (ujrestis, but have the front cheek-tooth showing the
angles characteristic of both these species, namely, 5 inner and
4 outer. There are many limb-bones which may belong to this
species or M. glureolus, or perhaps to M. ayreslis. M. arvalis has
been found fossil in the Forest Bed and in a fissure-deposit near
Frome. It is extinct in Britain, but is now living in Middle
Europe from the Atlantic to the Urals, and also in Western Siberia in
steppe regions. In the Alps it ascends to a height of 6000 feet.
Microtus ( = Arvicolu) agrestis. (Field- Vole.) — Portions of two
skulls, with the characteristic upper second cheek-tooth (0 points)
in place, undoubtedly represent this species ; and with these are
associated several lower-jaw rami, which are rather larger than
those referred to the last species, but have the form of tooth
(5 inner and 4 outer angles) characteristic of both M. agrestis and
M. arvalis. The limb-bones, which on account of their length might
be referred to this species, are not certainly determinable, the femora
especially being stouter and having larger heads than in the recent
specimen. Microtus agrestis has been recorded from English Caves ;
it is now living in Middle and Northern Europe, as well as in Britain,
and ranges southward as far as the Alps and Pyrenees (where it
extends to a height of 4000 feet), but is more plentiful in the north,
reaching in Scandinavia to 66° of north latitude.
Microtus (szArvicola) ratticeps. (Northern Vole.) PI. XT.
fig. 11. — Two lower-jaw rami and three of the characteristic teeth
are all that I am ablo to refer to this species ; but possibly some of
the portions ot skulls noticed under M. gregalis may belong here.
The front cheek-teeth still remaining in the jaws, as well as the
separate teeth, have each 5 inner and 3 outer angles, the anterior
prism being confluent with the fourth inner prism. This and the
three previously noticed species are so nearly of the same size that
it is probable some of the smaller limb-bones already mentioned may
belong to the present form. M. ratticrps has been found rn Caves
and other Pleistocene deposits. It is not now living in Britain,
but occurs throughout Northern Europe, from Scandinavia to the
Urals, and also over a large part of Siberia.
Microtus (=Arvicola) gregalis. (Siberian Vole.) PI. XI. fig. 12. —
Nearly forty small rami, varying somewhat in size, are referred to
this species on account of the structure of the anterior cheek-tooth.
This tooth has 5 inner and 3 outer angles, the anterior enlarged
prism being continuous with the fifth, but shut off from the
fourth inner prism. This form of tooth is much like that of
Digitized by Google
198
MR. E. T. NEWTON ON THE VERTEBRATE
[May 1894,
M. rattictps, for which it may easily be mistaken ; but in M. ratticeps
the front prism of this cheek-tooth is continuous with the fourth inner
prism, and is not shut off from it by the enamel fold, as it is in the
present species. There are portions of four skulls which may belong
to this species or to M. rattictps, the posterior cheek-tooth having
4 inner and 4 outer angles. Microtus gregalis has been found in the
Norfolk Forest Bed and in Pleistocene deposits on the Continent.
It is now living in the treeless regions of Siberia, east of the River
Obi.
Limb-bones of small Rodents. — In addition to the skulls and lower
jaws of small rodents above noticed, numerous limb-bones have been
met with ; but, while the jaws with teeth can be referred to the
genera and species given above, there is much difficulty in correlating
the other bones with them. The limb-bones, especially the femora
and humeri, may be separated according to their sizes and propor-
tionate robustness into about a dozen groups. The largest of these
bones agree satisfactorily with Microtus amphibius ; but few, if any,
of the others present a sufficiently close agreement with such recent
forms as I have been able to compare them with, to render a
reference certain. In many cases the fossil bones which seem
most nearly to resemble any particular living species are found to
be not only stouter, but to have proportionately larger heads. At
present, therefore, many of the limb-bones have not been specifically
determined.
Ungulata.
Elephas primigenitts? (Mammoth.) — The only evidence of the
Elephant in the Ightham fissure is supplied by one of the smaller
bones of the tarsus, a well-preserved third cuneiform bone of tho left
side, and possibly by some pieces of largo ribs. There is no doubt
as to the foot-bone belonging to Elepltas, and so little as to its being
Mammoth that I have placed it in this species. There is some
doubt as to whether the Mammoth occurs in the Forest Bed.
Equus caballus. (Horse.) — Portions of two scapulae, a piece of
femur showing the third trochanter, a first digital phalange, and a
splint-bone of a good-sized horse are referred to this species, the
Pleistocene form being now recognized as at most a variety of the
recent E. caballus. An ungual and one other phalange of a much
smaller horse have also been found. The domestic horse is almost
certainly identical with the form found so abundantly in Caves and
Pleistocene river-deposits, and extends back in time at least as far
as the Forest Bed.
Rhinoceros antiquitatis. (Woolly Rhinoceros.) PI. XL figs. 13-
15. — Four well-preserved milk-teeth of this species have been found ;
they are the first, third, and fourth deciduous molars of the left upper
jaw, and the third deciduous molar of the right lower jaw. The
upper teeth possess the completely separated median accessor)- valley
Digitized by Google
Vol. 50.]
FACNA FROM THE IOHTHAM FISSURE.
199
so characteristic of this species. The fourth tooth is only slightly
worn. There can be little doubt that those teeth all belonged to
ouo animal, and were most probably united by the jaw when first
unearthed ; they are in too perfect a condition to allow of the
suggestion that they have been derived from an older deposit, all
the edges being as sharp as when the animal was alive. The shaft
of a large and gnawed humerus and part of a much denuded atlas
vertebra most likely belong to this species. liMnoctros antiquitatis
is only known from Pleistocene and Cave deposits ; but in these
it has been found at many localities in England, Europe, and
Siberia,
Cervua elaphut. (Red Deer.) — Part of a scapula agreeing in
form with that of a red deer, but bigger than the specimen with
which it has been compared, is referred to this species, which it is
well known attained to a large size in Pleistocene times. This
scapula is not so large as that of C. ffiyanttusy and the spine does
not approach so near the glenoid cavity ; in size it agrees with that
of a small ox, but is not of the sarao form. A piece of lower jaw
with two milk-teeth in place is likewise referable to this species.
The red deer occurs in the Forest Bed aud in Caves and Pleistocene
river-deposits ; it is now living not only in Britain and the temperate
regions of Europe, but also in a large part of Siberia.
Rangifer(=Cervu*)tarandus. (Reindeer.) PI. XI. fig. 10. — A
portion of a right mandibular ramus, with two milk-teeth in place,
agrees so precisely, as regards the size and pattern of the teeth, witli
the lower jaw of a reindeer of similar age in the British Museum, as to
leave no doubt regarding their specific identity. The articular half of
a scapula, showing tooth-marks of a small carnivor, gives additional
definite evidence of the same species. On comparing the scapula
of a reindeer with those of the red and fallow deer, it will bo
noticed that the reindeer differs from both the latter in having the
spine descending nearer to the glenoid cavity, a smaller coracoid
process, and the prescapula wider, so that it forms a more distinct
ledge. The general effect of these differences is to give a less con-
stricted appearance to the region a little above the glenoid cavitv.
Two pieces of femora, although a little Btnaller than those of the
reindeer in the Museum of the Royal College of Surgeons, may
perhaps belong to this species. The reindeer, which is very common
in Caves and Pleistocene river-deposits, was still living in the North
of Scotland at the beginning of tho I'Jlh century. It is now
restricted to the far north in Europe, Asia, and America, its southern
limit following very nearly the isothermal line of 32° Fahrenheit,
and consequently it is found farther south in America than in tho
Old World.
Capreolus caprta. (Roedeer.) — A gnawed femur, two metatarsal
bones, and possibly a toe-bone, are all the parts of this species yet
found. The roedeer has been met with in the Forest Bed, also
in Caves and Pleistocene river-deposits; it now occurs over all
Digitized by Google
200
MR. E. T. XEWTOJT ON THE VERTEBRATE
[May 1894,
Europe, except much of Russia, and is scarcer in the northern
countries than it is in the south.
Sluep 1 Goat ? — There are two tibiae among theso remains, which
I am unable satisfactorily to determine ; but as it is possible that
they may belong to sheep or goat, it is perhaps best to mention
them.
Sits tcrofa. (Pig.) — The only specimen representing this species
which has yet been found is a single first upper-molar tooth.
The species is known in the Forest Bod, as well as in Caves and
Pleistocene river-deposits ; it is now living in Europe and in Asia,
extending beyond the 55th degree of north latitude, and occurs in
North Africa.
Carnivore.
Mustcla robust ay sp. nov. PI. XI. figs. 17, 18. — A left humerus, a
right ulna, and some foot-bones from the Ightham fissure undoubtedly
belong to the genus Mustela, but I cannot refer them to any known
species. Thoro can be no question as to their close relation to the
marten and polecat, agreeing as they do in minute particulars with
the corresponding bones of these animals ; in length, however, they
are intermediate between those two species, and are, at the same
time, absolutely stouter in build than the much longer bones of the
marten. The humeri of the marten and polecat used for comparison
present certain slight differences, and in these particulars the fossil
humerus agrees best with that of the polecat. The deltoid ridge in
the marten is not so strongly developed, neither is the front of the
humerus in this region so much flattened as it is in the polecat and
in this fossil. In the last two forms also there is a tino raised line,
accompanied by a narrow groove, extending from the inner side of
the deltoid prominence downward to the inner side of the epicondylar
foramen, which is not seen in the marten; and further, the marten's
humerus is more suddenly contracted above the epicondylar foramen
than in the other two forms. The strong supinator ridge and
entepicondylar foramen are similar in all three humeri, but the ridge
is proportionately strongest in the fossil, in which also the width of
the distal end of the bone is absolutely greater than in the marten.
The length of this fossil humerus is 54 mm., the width of the
proximal end 12 mm., width of distal end 15 mm., the smallest
circumference of shaft 16*5 ram.
The ulna, as already stated, is intermediate in length between
that of the polecat and marten, but is absolutely stouter than in
the marten, and the olecranon process is especially broad. The
inner and distal end of this ulna has the prominent, elongated, and
sharp ridge found in Mustela ; while the opposite side of the bone
near the middle has a well-marked prominence for the attachment
of the ulno-radial ligament.
Two metacarpals and a metatarsal, which are intermediate in
sizo between the same bones in the polecat and marten, while
Digitized by LiOOQle
Vol. 50.J
FAl'NA KKOM THE IGIITH AM FISSUHE.
201
baring a similar form, are referred to this species, as well as a single
upper canine tooth larger than that of the polecat. As it is desirable
that this new form should have a name, I have called it Mvstcla
robusta.
Mustela vulgaris, var. minuta. (Small Weasel.) PI. XI. figs. 19,
20. — A small, right mandibular ramus, with most of the teeth in
place, is certainly that of a Mustela, and although smaller than any
specimen of M. vulgaris with which I have been able to compare it.
would correspond with the smallest skull of this species measured
by Hensel.1 Two adult tibiae, with epiphyses firmly ankyloscd, and
agreeing with those of the common weasel in every particular except
size, are included with the lower jaw as a small variety of Mustela
vulgaris, which is the smallest known carnivor. These tibiie are each
18*5 millim. long, which is nearly one third shorter than that of
an ordinary -sized weasel, and a little less than that figured by
WoldHch 2 as Fcetorius minutus, or than would correspond with the
mandibular ramus above mentioned. The weasel has been recorded
from Caves ; besides being a native of Britain, it is generally distri-
buted throughout Europe, extending into Northern Russia and over
a large part of Siberia.
Melts taxus? (Badger.)— Several bones of a very young animal,
without epiphyses, are believed to be those of a badger, but I have
been unable to compare them with a similarly young recent speci-
men, and the determination is therefore uncertain. This species
has already been found in Caves and Pleistocene river-deposits in
Britain ; it now ranges over the whole of Europe, including Britain,
from the Mediterranean northward, beyond (ill0 of north latitude.
Ursus arctos ? (Brown Bear.) PI. XII. fig. 10.— The metacarpal
of a bear, which has the proximal articulation destroyed, is all that
has been found of this genus. In size and form this bone agrees best
with the fifth metacarpal, left side, of Ursus arctos, but the specific
determination is not quite certain. The brown bear has been found
in Pleistocene deposits, and, although extinct in Britain, is now living
throughout Europe and Asia, extending even into North America.
It ranges southward to the Pyrenees and northward nearly to 70°
of north latitude.
Uycma crocuta ? (Spotted Hyama.) PI. XII. fig. 1 1.— Although
several bones have been found evidently gnawed by Hy^na, especially
a humerus of Rhinoceros, of which only the middle of the shatt
remains, yet the sole direct evidence of the genus is a single much
denuded canine tooth, which is not sufficient for specific identification.
Hycsna crocuta has been found in the Forest Bed, Pleistocene river-
deposits, and Caves : it is now confined to Africa, south of the Sahara.
Canis vulpe*. (Common Fox.) PI. XII. figs. 1-4.— The Ightham
fissure has yielded numerous bones of foxes, representing nearly
1 Nora Acta Acad. Leop.-Carol. vol. xlii. (1881) p. 125.
2 Denkachr. <L k. Akad. d. Wiwensch. Wien, vol. ix. (1893) p. (J14.
Q. J. G. S. No. 198. p
Digitized by Google
202 MR. E. T. NEWTON ON THE VEBTBBRATE [May I 894,
all parte of the skeleton. These bones naturally fall into two
sets ; one agreeing in size with the common fox, and another
in which all the bones are of a smaller size. The latter set
evidently belong to a second species, Cards lagopus, and will be
noticed below. The larger bones are the most numerous, and are
unhesitatingly referred to Cams vulpes : the jaws and teeth, as
well as the other bones of the skeleton, presenting no characters
either of size or form different from those of C. vulpes. Some of
the bones, as will bo seen by the measurements, are larger than
those of the female fox given for comparison, and doubtless belonged
to a male, while some appear to have belonged to a smaller example.
The common fox has been found in Caves and in Pleistocene river-
deposits ; it is now living throughout the greater part of Europe
and Asia, ranging from Britain and Scandinavia to Kamtchatka, as
far northward as trees nourish ; it is also met with in Africa, north
of the Sahara.
Measurements of Foxes' Bones (in millimetres).
Length of entire row of cheek-
teeth of lower jaw
ditto ditto upper iawi
Length of lower carnawial ...[
„ upper „ outside
femur ! 130
tibia
humerus
radius
ulna
c.
vulget.
C. lO£
6
jopus.
2
C. vulpes.
Ightham.
1
C. lagopus.
Ightham.
60
53
49
58 to 61
49 to 50 5
545
48
44
50
45
164
13-5
13
15 to 16 5
12 5 to 13-6
125
12
13
12
130
110
100
123 to 132
104
142
126
113
134 to 135
110 to 114
123
111
96
117 to 127
•H)
118
103
92
108 to 119
91
139
122
108
143
106
Canxs lagojnts. (Arctic Fox.) PI. XII. figs. 5-9. — The series of
smaller canine bones, which are referred to this species, includes
upper and lower jaws with the cheek-teeth, as well as representatives
of each of the limb-bones and many of those of the feet. Only the
complete bones have been used for the measurements given in the
table, and it will be seen that one of them, the radius, is a trifle
smaller than that of the female C. lagopus, while all the other
measurements are intermediate between those of the same parts in
the male and female C. lagopus.
Dr. Woldfich1 has used the name of Vulpes meriUonalis for certain
fox-bones from the 4 Diluvium ' which are said to be smaller than
C. lagopus and to have a proportionately narrower upper carnassial
tooth. The upper carnassials, preserved in the jaws from Ightham,
are slightly more compressed than in the C. lagopus, referred to by
Dr. Woldfich, and closely resemble those of V. meridionalis, but
1 Denkschr. d. k. Akad. d. Wisaensch. Wien, vol. xjotix. (1878) p. 143; also
Sitzungsb. d. k. Akad. d. Wisaenach. Wien, toL lixxii. (1880) p. 38.
Digitized by Google
Vol. 50.]
FAUNA FROM THE IGHTHAM FISSURE.
203
this, it BeemB to me, may be due to individual variation; and
seeing that the other measurements fall so well within the limits of
those of C. lagopug, I regard these Ightham remains as belonging
to the Arctic fox. So far as I am aware, the only record of the
Arctic fox in Britain was made by Busk in 1875, 1 when he de-
scribed an axis vertebra from Cresswell Crags ; but Dr. Black more,
of Salisbury, tells me that in 1879 he obtained a skull of this species
in the brick-earth of Fisherton. It is satisfactory, thorefore, to be
able to confirm these discoveries by the finding of a number of
specimens in the Ightham fissure. Cant* larjopu* is now living in
the Arctic regions of Europe, Asia, and America, and also in Spitz-
bergen and Iceland.
III. Table of Distribution of the Vkbtebrata found in
Ightham Fibbube.
N = rauge north. S = range south. A = Arctic.
Names of Genera
and Species.
Amphibia.
liana trmporaria, Linn. .
Dufo vulgaris, Laurent .
.Volga (=Triion)
Tardus musicus 1 Linn.
Reitilia.
Anguis fragilis, Linn
IVapidunoius matrix, Linn
Viprra (fV/ios) krus, Linn *
Motacilla t
Anthus pratensU f Linn.
Alauda arvensis, Linn. ...
Buteof
Amw tnwoj* ' Linn
*
•
ritain.
'5
*c
pq
c
no
toft
a
if*
■
t-J
ft
\
*
*
*
*
*
*
i
1
*
*
*
*
*
*
?
*
#
*
N.S.
N.S.
*
*
N.S.
*
N.S.
*
N.S.
*
*
*
N.S.
#
I
«
1 Quart. Journ. Geol. Soc. vol. vxxi. p. <>&"».
P2
204
MR. E. T. NEWTON ON THE VERTEBRATE
Table (continued).
[May 1894,
Names of Genera
and Species.
Mammalia.
Talpa wopaa. Linn. ...
Sorer rutyaris, Linn *
/>//// menu*, Pallas *
V<*l«-rt'i/i<> Sattarri, Kuhl *
. si». t
Scotophilia pipi*trrilu&! CJeoff. *
Plcco'if* auritusl Linn *
Lepvs timidus, Linn *
/ funiculus, Linn *
Ijigomys pusi/fu*, PallaB ...
S pernio philua
Mit.s xi/lvaticm, Linn.
Abbtttti, n. ap. . .
Myotics Icuimu*, Linn.
torquatus, Dcsni.
-*-»* ........ *•
Microtwi ( — Arrif ofrt) ylarrolus, Schreib. .
(-• • ) umphihius, Linn
( ) r/r {(///>, I'allag
*
*
( ) ay rcstm. Linn *
<- ) rat tier p.*, K.iB
( ) grryalis. l'allas
Kltph a* prim igrnius ! Blum
Eqiius rahaflus, Linn *
lihiiUKeroa uitfiqitifafiK, Blum ...
(Wvits etaphus. Linn. #
Kanyifrr ( — Orvun) tarandut, Linn
l.'apreulun coprca, Umy *
Nk.s s^ntfit. Linn #
\]u*trla robtttfa, n. sp
vttlyarit, var. miniita ?
.V</r * foj-M.i / Bodcl ♦
I'/vus flrc^.v / Linn ...
Hytma trocu/a ! Krxl
(•Wmi.« cu/pes, Linn. *
togt.pu*. Linn. ...
N.
N M0.
N.S.
•
?
N«0°.S.-
N«03.S.
N.S.
S.
•
N.
#
...
N.
A.
N.S.
N.S.
#
n a;0, s.
N.
#
1 • *
*
N.
S.
#
*
N7(»°.S.
S.
N.S.
A.
*
*
«
*-
*
«
»
*
-
-
*
*
*
»
«
*
♦
»
*
*
*
*
*
IV. Conclusions.
The sj»ecics recognized from the Ightham fissure may be divided
into three groups: — 1. The extinct forms. 2. Those which are
extinct iu Britain, but are still living elsewhere. 3. The species
still living in Britain. Of the extinct forms only three or four have
Digitized by Google
Vol. 50.]
FAUNA FROM THK IGHTHAM FI9SUIIE
205
been found in this fissure : Rhinoceros antiquitatis, EUphas primi-
gtniust, and the new species of Must da and JUus; but it must be
remembered that the number of extinct mammals comprised in the
Pleistocene fauna is comparatively small. Of the 48 species noticed
by Prof. Boyd Dawkins in 1869, only 11 are extinct.
No doubt much uncertainty exists as to the exact time when
some of the smaller mammals became extinct in this country, for
unlike the larger animals (such as the urus) which were noticed by
very early writers, such small forms as the northern vole aud
Arctic lemming would not attract attention, even though they
should have continued in the country to much later times. It is
unlikely, however, that species now restricted to steppe and Arctic
conditions would have continued to live in Britain when the
climate became temperate. Moreover, there is no evidence of their
remains having been found in alluvial or other recent deposits. On
the other hand, it is quite certain that the smaller mammals were
more capable of adaptation to extreme changes of condition than
were the larger ones. The field-mouse and some of the voles
which lived in Britain in the times of the Norfolk Forest Bed are
living here at the present day. Few, if any, of the larger species
have been able to maintain their position ; but this no doubt is
largely due to the influence of man.
A mere glance at the list of species from the Ightham fissure shows
how large a proportion of them are forms now living in the district
(about 32), and these give so recent a look to the entire series that
it may naturally be questioned whether this deposit is anything more
than a recent accumulation. The fact that some extinct forms aro
found mixed with the recent species is not in itself a sufficient answer
to this question. At first sight it seoms quite possible for the extinct
forms to have been derived from some Pleistocene deposit on the
higher ground, which has now been entirely removed by denuda-
tion, and these, being gradually washed into this fissure from above,
might have been re-deposited with the recent species in quite modern
times. There are, however, two reasons which militate against
this supposition ; in the first place, if this were the correct inter-
pretation, we should expect to find the two series of bones in a very
different state of preservation, the derived bones being rolled and
denuded ; but such is not the case, for although one or two speci-
mens have been partially dissolved, apparently by exposure to
percolating water, the Rhinoceros teeth are as sharp and perfect as
they can well be ; the large Rhinoceros humerus shows no signs of
having been worn, to any appreciable extent, since it was gnawed ;
the elephant foot-bone is likewise unworn. And, further, the skulls
and bones of the small species, such as the lemmings and northern
voles, which are not known to have lived in this country since
Pleistocene times, are just as perfect as those of the recent species
found with them. The second argument against the deposit being
recent is derived from the physical conditions of the locality. This
fissure is situated at the end of a small promontory on three sides
206
MR. E. T. NEWTON ON THE VERTEBRATK
[May 1894,
of which there is a stream, and the superficial area of the pro-
montory is too small for the accumulation of water in sufficient
quantity to carry in the larger specimens. Besides this, the
fissure is open at one end to the valley, and in this condition could
scarcely be filled with the deposit nearly to the top as it now is.
If, on the other hand, it is contended that the filling of the fissure
took place before the excavation of this valley, and consequently
before the formation of the system of valleys of which this is only
a part, it will be necessary to date back the formation of this
deposit so far as practically to concede its Pleistocene age.
It seems possible that the fissure might have been partly filled in
Pleistocene times, and that the recent species found their way
in at a later date. If this were so, then the Pleistocene species
should be found at the bottom and lower parts, and the living
species at the top and higher parts ; but such is not the case. When
first Mr. Abbott began collecting these remains, it was only the
upper part of the fissure which was accessible, and the specimens
found were carefully kept by themselves ; afterwards, at about
halfway down, some Rhinoceros teeth were obtained, and subse-
quently other specimens were found at the lower part of the fissure.
A list of the species from both parts was kept, but it soon became
evident that the upper and lower parts yielded the same species.
The living species occurred at the bottom as well as at the top,
while the Arctic lemmings and northern voles were found near the
top as well as in the lower parts. It is tolerably certain, there-
fore, that the deposit is of about the same age throughout. The
possibility that in recent times the fox, badger, mole, and rabbit
may have burrowed into the accumulated earth, and have left their
remains in the burrows, to bo mixed with the earlier forms, is a
supposition that has been duly considered. In so far as the rabbit
is concerned, this is probably correct, for the remains are not satis-
factory and the species is not certainly known in Britain as a
Pleistocene form. Some of the mole- and fox-remains might in
like manner have found their way into the deposit, and the birds
might have been carried in by the foxes. But if this view be
accepted, it practically acknowledges the Pleistocene age of the
mass of the deposit. There is, however, another standpoint from
which to view the remains of the still living species. If we except
the smaller birds, very few of which have been recognized in
Pleistocene beds, nearly the whole of the remaining species in the
foregoing list have been recorded from Cave-earth, or other Pleisto-
cene deposits, in various parts of Britain, and several of the species
extend back in time as far as the Norfolk Forest Bed.
Seeing, then, that there is in this fissure a fair number of the
characteristic Pleistocene species (2 forms quite extinct, and 1 1
extinct in Britain though living elsewhere) mixed with living
species which are known to have lived in Pleistocene times, there
seems no reason for doubting the Pleistocene age of these represen-
tatives of living species ; and it becomes highly probable that to
the same period belong those other living species which are mixed
Digitized by Google
Vol. 50. j
FAUNA FROM Til h IOHTHAM KISSURE.
with them, but which have not before been recorded from beds of
so early a date. I am disposed, therefore, to regard all the species
found in this fissure, except the rabbit, as of Pleistocene age.
One of the most interesting species found in the Ightham fissure
is the reindeer, which has also been met with at Boughton,
Otterham, and Sittingbourne. It is a remarkable fact that
although this species is abundant in the Thames Valley west of
London, and has also been found both to the north and south of
the lower parts of the Thames Valley, as well as in many Caves,
it has never been met with in the brick-earth of the Thames Valley
itself to the east of London. This circumstance, combined with
the occurrence of Rhinoceros megarhinu* in these deposits of the
Lower Thames Valley, led Prof. Boyd Dawkins to regard the latter
deposits as of an earlier date than those containing remains of
reindeer, but without the megarhine rhinoceros ; and while advo-
cating for them a very early Pleistocene origin,' he acknowledged
that they were certainly of later date than the Norfolk Forest Bed.
About thirty species of mammals have been found in the brick-
earth of the Lower Thames Valley, and half of these occur in the
Ightham fissure, but if Prof. Boyd Dawkins's separation of the
former deposits as representing an earlier part of the Pleistocene
be correct, then the presence of the reindeer at Ightham would
prevent that deposit from being regarded as of the same age as the
Lower Thames Valley brick- earth, and point to a relationship with
some other part of that period. Indeed, there can be little doubt
that, whatever may prove to be the relation of the Lower Thames
Valley brick-earth to other Pleistocene deposits, the Ightham-fissure
fauna is most nearly related to that which is found in British
Caves.
Much interest attaches to a correct knowledge of the climate
prevalent during the Pleistocene period, indications of which are to
be found iu tho Arctic Freshwater Bed of Norfolk, the Boulder
Clay, and the animals which are found in the various deposits.
The probability of alternations of warmer and colder periods during
Pleistocene times has long been advocated ; but it has been thought
possible by some that, with a more continental climate than at
present prevails in Britain, the alternations of summer and winter
might be sufficient to account for the seeming mixture of species.
The latter supposition, however, seems scarcely tenable.
Recently the possibility of steppe conditions having extended
much farther westward in Pleistocene times has been advocated
by Dr. Woldrich,2 by Dr. Nehring,11 and my colleague Mr. Clement
1 Quart. Journ. Geol. Soc. vol. xxv. (1869) p. 212.
* ' Die dilurialen Faunen Mitteleuropas,' Mitth. Anthrop. Gosellsch. Wien,
toI. ii. 1882.
3 • Ueber Tundren und Steppen der JeUt- und Vorzeit/ Naturwissenwih.
Wochenschrift, vol. v. (1890) pp. 451 and 47f» ; see also separate work, published
at Berlin, 1800
Digitized by Google
■
208 MR. E. T. HBWT05 ON THE VERTEBRATE [May 1 894,
Reid,1 and it is interesting to see how far the material found at
Ightham confirms, or militates against, such a possibility. The
Arctic lemming and the Arctic fox are now restricted to the far
north and to Arctic conditions. The voles, although some of them
are living in temperate regions, all extend far to the north, and
two of them (Microtu* raltictps and M. gregalis) are characteristic of
desert or steppe conditions. The moles and shrews, though living
in Temperate countries, extend far to the north in Europe and Asia,
and may well have existed in Britain in a cold or steppe climate.
The species of bats which have been found likewise have a wide
distribution, and most, if not all, range to 60° of north latitude.
The common hare, which extends southward, is also found living
in the north of Russia. The pika (Lagomys pusillus) is a Siberian
and South Russian species, and with the Spermophilus is very
strong evidence in favour of steppe conditions. The mammoth and
woolly rhinoceros are known to have lived in the far north,
although their recent representatives are tropical animals. The
reindeer is now an inhabitant of the far north. The red- and
roedeer have a wide range, but the latter is essentially a South
European form. The brown bear and the common fox extend
far into the north, while the Arctic fox, as already noticed, is
found only in the northern icy regions.
The hyaena found at Ightham seems to bo identical with the
Pleistocene species, which is now living in tropical Africa, and is
the one conspicuous form at Ightham which, when compared
with the associated species, seems to be so strikingly out of its
latitude. However, as is well known, there are species from other
Pleistocene localities which seem likewise to indicate a warmer
climate— namely, the lion, hippopotamus, and probably the re-
maining species of rhinoceros and elephant. Rut besides these
must be noticed two other species not found at Ightham, which
point in an opposite direction— namely, the musk ox and the
Saiga antelope, one of which is altogether an Arctic species, while
the other is just as definitely characteristic of the Steppes.
Whatever may be the cause, the Pleistocene fauna, as found in
the Brick-earth, Gravel, and Cave-deposits, seems to be of a mixed
nature, the species finding their nearest allies at the present day
living under widely diverse climatic conditions. Some of the
Pleistocene species thus indicate extreme cold, others point dis-
tinctly to steppe conditions, while a third series seems just as
strongly to prove the prevalence of a warm climate.
These difficulties will doubtless eventually bo removed, but in
the meantime too much stress must not be placed upon the range
of recent animals as an indication of that of the past, seeing that
there are many circumstances besides climate which help to deter-
mine the distribution of species, circumstances concerning which we
have, at present, but little information.
1 « Natural Science,' toI. iii. (1803) p. 307.
Digitized by Google
Vol. 50.] FAUNA FROM THE IGHTHA* FISSURE. 209
EXPLANATION OF PLATES X.-XII.
All are specimens from the Ighthara fissure, and the figures are of the
natural size unless otherwise stated.
Plate X.
Fig. 1. Rana temporaria. Humerus : a, front view ; b, side view.
2. ,, „ Biconcave penultimate vertebra, seen from below.
3. „ „ Left ilium, outer surface.
4. Bufo vulgaris. Bight ilium, outer surface.
5. Anguis fragilis. Portion of investing bony scales.
6. „ „ Two scales, enlarged, showing broad edge overlapped
by next scale.
7. ,, „ Left ramus of lower jaw.
8. Vipera berus. Left ramus of lower jaw, wanting anterior end.
9. „ „ Vertebra, showing depressed articular cup.
10. Alauda arvensis (8kylark). Bight humerus, front view.
11. „ „ ,. Bight united metacarpals.
12. „ „ „ Right tarso-metatarsus, seen from behind.
13. Saricola (Enanthr. Left humerus, front view.
14. „ „ Bight united metacarpals. (This figure represent?
the bono as too robust.)
15. Lartis? Bight humerus: a, front view ; 6, side view.
16. Anas hoscasl Left humerus : a, front view ; b, side view.
17. Anas . Left ulna.
18. Buteo f Left tarso-metatarsus, wanting distal end : a, outer surface ;
b, seen from behind.
Plate XI.
Fig. 1. Sorex vulgaris. Skull, side view. Xj.
la. „ Lower jaw, right ramus. X}.
2. Sorejr pygmam. Skull, side view. x|.
2a. „ „ Lower jaw, left ramus. x|.
3. Ve*pertilio Nattereri, Skull, seen from below. X j.
3a. ,, „ Lower jaw, right ramus. X|.
3 b. „ „ Femur, natural size.
3 c. „ „ Humerus, nntural size.
4. Ltpus timidus. Left femur, front view, natural size.
4 a. „ „ „ „ inner side,
no. „ „ Bight humerus, front view.
5. „ ,, ,, ,, inner side.
f>. Isogomys pusitlus. Lower jaw, left ramus.
6 a. „ „ Cheek-teeth, xo.
7. Mtu syivatkus. Lower jaw, right ramus, with one cheek-tooth.
7 a. „ „ Two lower'cheek -teeth, yb.
8. Mus Abbott i, n. sp. Lower jaw, left ramus, with three cheek -teeth.
8a. ,. „ Cheek-teeth of same. X5.
Lower jaw, left ramus, front cheek-tooth restored
from another specimen.
9 a. „ ,, Grinding surfaces of cheek teeth. x5.
10. „ torquatu*. Lower jaw, left ramus.
10 a. „ „ Grinding surfaces of cheek-teeth of same. x5.
11. Microtus (Arvicola) ratticeps. Lower jaw, right ramus, with two
cheek-teeth.
1 1 a. „ „ „ Grinding surfaces of cheek-teeth of
same. X 5.
12. „ „ grrgalis. Lower jaw, left ramus, with three
cheek-teeth .
12a. „ pi „ Grinding surfaces of cheek-teeth of
same. X 5.
13. Rhinoceros antiquitatis. First, or front, upper deciduous milk-molar.
14. „ „ Third milk-molar.
15. „ „ Fourth milk-molar.
Digitized by Google
210 VERTEBRATES FROM TUB 1GHTHAM FISSURE. [May 1894,
Fig. 16. Rang\fer taraudus. Part of lower jaw, right ramus, with two milk-
teeth in place.
16 a. „ „ The two teeth seen from above.
17. Mustek robtuta, n. sp. Left humerus, front view.
17 a. „ „ Same bone, outer side.
18. „ „ Right ulna, inner side.
19. „ vulgaris, Tar. minuta. Lower jaw, right ramus.
20. „ „ pi Left tibia, front Tiew.
Plate XII.
Fig. 1. Cants vulpes. Right femur.
2. „ „ Right humerus.
3. „ „ Right mandibular ramus.
3 a. „ „ Teeth of same, seen from above.
4. „ „ Ri|ht upper jaw.
5. ,, lagopus. Left femur.
5 a. „ ,, Same bone, inner Tiew.
6. ,, ,, Tibia.
6 a. „ „ Same boue, proximal articulation.
6 b. „ „ Same bone, distal articulation.
7. „ 1, Right humerus.
7 a. „ „ 8ame bone, inner side.
8. „ „ Left mandibular ramux.
8 a. „ Teeth of same from above.
9. „ „ Right upper jaw.
9 a. „ „ Same, palatal view.
10. Ursus arctos ? Left fifth metacarpal.
11. Hyana crocuta ? Canine tooth, much denuded.
Discussion (on the two preceding Papers).
The President said it was greatly to be regretted that Mr. Abbott
was unable to be present at one of the best-attended meetings of
the Session.
Mr. Toplet compared the fissures filled with loam and gravel,
and containing mammalian bones and land-shells, of the Maidstone
district with the interesting example now described, and explained
that those of the Maidstone Rag country were connected with
overlying deposits of drift, the material now filling the fissures
having been let down into the rock by solution of the limestone
along joints and cracks. He now thought that some of the wider
pipes of brick-earth of the Maidstone area may be partly due to
slipping of the rock over the Atherfield Clay below, letting down
the overlying drifts bodily into the long spaces thus formed. The
numerous fissures near Maidstone had been so carefully noted by
tho late Mr. Bensted and his son during many years, that it seemed
unlikely that such interesting deposits of bones as Messrs. Abbott
and Newton now described could have been there overlooked.
The Boughton 4 fissure ' or 4 cave,' described by Buckland and
referred to by Murchison, was not near any important deposit
of drift, and this fissure more resembled that at Ightham; the
latter probably somewhere had communication with the surface.
Mr. Toplcy reforrod to a diagram exhibited by the Author
illustrating his views as to a reversal of drainage in the Shode
Valley area : tho higher gravels having been formed by a stream
which flowed northward towards the Darent from the Lower
Greensand escarpment, which then stretched far to the south over
Digitized by Google
Quart. Jo-urn. Geo]. Soc .Vol. L PI . X.
Quart Joum.Gcol.Soc Vol L.Pl.Xf.
10
9a ;
8
Jl
12a xf
/a «
i
8a*f
SO
2x $
-.4
Mil t. »;;■». Bl o» jmci
Digitized by Google
■:'af.n:vora ff
Digitized by Google
Oaeurt- linurn .QhoI. Soc .Vol . L . Pi. XII
Digitized by Google
Vol. 50.]
FIS8URES NEAR IGHTH AM DISCUSSION.
21)
the Weald Clay. He was not at present (nor was Prof. Prestwich)
prepared to accept this view, although there are many difficulties in
explaining the origin of gravels near the existing watersheds ; hut
similar difficulties occur in other parts of the Wcalden area.
Sir Henrt Ho worth desired to express his admiration of the
work of Mr. Abbott. While Dupont at Brussels and Nehring at
Berlin have been carefully working out the remains of the small'
mammals found in the Pleistocene beds and the caves of those
countries, we have done little in this respect since Sanford and
Dawkins's exploration in the West of England, our attention having
been largely limited to the larger mammals. The careful and laborious
work of Mr. Abbott and Mr. Newton on the products of this fissure
had therefore removed an opprobrium from English geology.
The tooth of the hyaena on the table was labelled crocu'ta, which
doubtless means the old H. spelcea. To call it crocuta, unless the
attribution is quite certain, is somewhat dangerous ; but Mr. New-
ton seemed to identify it with //. bmnnea, a very different beast
with a very different history. He (the speaker) had a great dislike
for the formation of new species on insufficient evidence. In a genus
so variable as Mustela it would be well to compare theso bones
with skeletons of the 6tch and other American living species, before
burdening our lists with a new name on the grouud of a somewhat
larger size in the bones merely.
In regard to Mr. Abbott's theoretical views, he could not believe
that these bones wero carried into the fissure by river-action. Any
river powerful enough to have carried along with it the large pieces of
mammoth and rhinoceros-bone would have scoured the fissure of all
these minute bones, which showed no trace of breakage or of wear.
The absence of fish-bones and of fluvial molluscs, and of the ordinary
wreckage of a river, were strongly against the view. On the other
hand, the presence of bones gnawed by hyaenas, the occurrence of so
many frogs' bones and the bones of bats, most unlikely animals to
be found in a river-bod, pointed to the so-called fissure having been
a cave. The beautifully sharp and unweathered condition of tho
bones also showed that they were not exjwsed to the air even for one
season, but had been carefully protected by a roof. It was such an
assemblage as we should expect in a hyaena-den which was also
frequented by large owls that fed on the small rodents, the frogs,
etc., and also by bats. Hence also the groat variety of species
which marks the larder of some raptorial beasts and birds.
If a cave, as he would certainly maintain, the question of how
the bones were found as they occurred involved a great many con-
siderations, which he had discussed at great length in the chapter on
Caves in * The Mammoth and the Flood ' and which thero was not
time to discuss now.
Dr. Henry Hicks also spoke.
Mr. E. T. Newton, in the absence of Mr. Abbott, thanked the
Society for the cordial reception accorded to both their papers, and, in
reply to remarks by Sir H. Howorth, said that the balance of evidence
was in favour of the hyaena's tooth belonging to Hymna crocuta.
Digitized by Google
212 SIR ARCHIBALD OEIKIE ON THE BASIC AND [May 1 894,
16. On the Relations of the Basic and Acid Hocks of the Tertiart
Volcanic Series of the Inner Hebrides. By Sir Archibald
Gkikie, D.Sc, LL.D., F.R.S., F.G.S. (Read February 21st,
1894.)
[Plate* XIII. & XIV.]
Contests.
Page
1. Introduction '212
II. The Gabbro Bosses 216
III. The Oranophyre Bosses 218
IV. Conclusion 227
I. Introduction.
Before entering upon the special subject of the present paper, I
wish to be permitted to make certain personal explanations which
appear to me to bo necessary on this occasion. Having in my
early years had the good fortuno to spend much time among the
Western Islands of Scotland, I was soon fascinated by the geological
features of that picturesque region. Like most young geologists, I
began with the fossils and collected largely from the Jurassic
formations of Skye and the adjacent islands, though the interesting
problems presented by the general structure of the area, and more
particularly by the igneous rocks, could not wholly escape the
attention of an enthusiastic beginner. The results of these youthful
labours were eventually communicated to this Society in the year
1S57.1
Having been appointed to the Geological Survey in 1855, I had
tho inestimable advantage of a practical training in methods of
detailed geological mapping, and it so happened that this training
lay, in large measure, among the ancient volcanic rocks so copiously
developed among the Old Red Sandstone and Carboniferous forma-
tions of Central Scotland. I was thus led from the very outset to
take a keen interest in volcanic geology, and the experience gained
among the records of Paheozoic eruptions induced me to return to
tho study of the latest series of volcauic outbursts in Britain — those
of tho Western Isles. From time to time 1 communicated to the
Royal Society of Edinburgh accounts of my investigations.3 At
last, in the year 1871, 1 had advanced far enough to be able to
present to the Geological Society a general outline of the Tertiary
volcanic history of Britain.3 I therein endeavoured to show how
extensive in area, varied in petrographical character, and protracted
in geological time were the Tertiary* eruptions within the area of
out islands. This paper was intended to bo the first of a series,
1 Quart Journ. Geol. Soc. vol. xiv. p. 1, 'On the Geology of Strath, Skye.'
3 See in particular Trans. Roy. Soc. Edin. vol. xxii. (1861) p. 649 ; Proc.
Roy. Soc. Edin. vol. vi. (1867) p. 71 ; also Brit. Assoc. Ren. 1867, Sections, p. 49.
* Quart. Journ. Gool. Soc. vol. xxvii. p, 279, 'On the Tertiary Volcanic Rocks
of the British Islands.— First Paper.'
Digitized by LiOOQle
Vol. 50.]
ACID ROCKS OP THE INNER HEBRIDES.
but as I could only snatch a few brief weeks of annual holiday for
this extra-official work, my progress could not be rapid. Before J
was able to offer to the Society my second communication, Prof.
Judd, at the beginning of 1874, read before the Society a memoir
' On the Ancient Volcanoes of the Highlands.' 1 As he had been
so fortunate as to be enabled to devote many months of continuous
labour to tho investigation of the region, he succeeded in covering
the ground which I meant to occupy. In the belief that in a large
part of my own undertaking I had thus been forestalled, I laid aside
the design of continuing the series of papers already begun in our
Journal.
Prof. Judd's paper was undoubtedly a bold and brilliant
piece of work. Though he had had no previous experience of
igneous rocks, he gathered together a large series of observations
and generalized from them so ingeniously and suggestively that his
memoir attracted a large amount of notice. And yet, from my own
experience in these Western Isles, I knew that there were many
difficulties which he had not explained. It was not, however, until
the year 1879 that, in the course of a journey through some of the
volcanic tracts of Western America, I began to see, as I believed,
the meaning of some of the phenomena which had for so many years
puzzled mc in the West of Scotland. My old love of the subject
and of the scenery of the Inner Hebrides was re-kindled, and then,
in these wilds of the Far West, I determined to take up once more
the study of the history of our Tertiary Volcanoes. At such intervals
of leisure as could be seized in the midst of a busy official life, I
worked at the subject and, after nine years, was enabled to complete
my task.
So long a period of time had elapsed — no less than seventeen
years — since the publication of my paper on Tertiary Volcanic
Rocks in our Quarterly Journal, that it was obviously undesirable
to attempt to resume tho series of which that paper was intended
to be the ftrst. I therefore turned to the Royal Society of Edin-
burgh, which had published my earliest writings on the subject, and
offered to it a somewhat voluminous monograph. Tho Council of
that Society accepted my communication, and published it in its
* Transactions ' during the autumn of 1888.2
In retracing ray former footsteps among the Inner Hebrides and
in traversing fresh ground, I was led to form conclusions very
different from some of those which had been arrived at by Prof.
Judd. It is not necessary for my present purpose to enumerate
these differences of opinion ; I will allude to one only, perhaps the
roost important of all, inasmuch as it affects tho whole order of
interpretation of the volcanic history. Prof. Judd, as I found
from copious evidenco collected all over the region, had mistaken
the true sequence in the protrusion of the volcanic masses of the
Inner Hebrides, putting the great bosses of acid rocks at the begin-
ning instead of at the end of the series. It would have been to me
1 Quart. Journ. Oeol. Soc. toL xxx. p. 2"20.
a Trans. Hoy. Soc. Eclin. toI. xxxv. pp. 21-184.
Digitized by Google
214 SIR ARCHIBALD GEIKIE ON THE BASIC AND [May 1 894,
an exceedingly distasteful task to indicate all the points in regard
to which I thought him to be in error. But it was impossible to
avoid reference to the more important of them where general prin-
ciples or important deductions were at stake. The indication of my
dissent from his views was done as lightly as possible ; I referred
to his writings more frequently when I could do so in agreement
with him than where I differed from him, and I feel confident that
no one who had not previously made himself master of the subject
would ever imagine from reading my memoir that the differences
of opinion between us were so profound as they really are.
As my memoir was based on detailed observations over the whole
volcanic region, prolonged through a series of years, during which I
repeatedly re-examined some parts of the ground, any adequate
criticism of it could only be founded on a careful study of some of
the numerous sections cited by me. Without waiting, however, for
the opportunity of testing the value of my deductions by an exami-
nation of the field-evidence from which they were drawn, Prof.
Judd at the beginning of 1889 communicated a general criticism of
my paper to this Society.1 In the discussion which followed the
reading of his paper I briefly replied. But, as it appeared to me
that no valid arguments had been adduced by him against either
my facts or my conclusions, I refrained from entering into further
controversy.
In a subsequent paper, on * The Propylites of the Western Isles
of Scotland/ Prof. Judd affirmed that " the great cause of the
conflict of opinion between us concerning the relations of the igneous
masses of the Western Isles of Scotland is to be found in the different
interpretation avo place on these propylitic rocks." 2 Though this
statement appeared to me to convey a very erroneous representation
of the actual difference of opinion, I declined to make any reply.
The main fundamental facts of geological history on which we dif-
fered remained quite clearly defined, and, in spite of the array of
petrographical learning brought forward by him, he seemed to me
to leave my version of the true sequence of events in the volcanic
history absolutely as it was. Disliking controversy so thoroughly
as I do, I even refrained from replying to what I regarded as mis-
conceptions or misstatements of my views, being content to abide
the verdict of competent geologists, who would doubtless review the
evidence on the ground.
My critic has now returned a third time to the attack in the paper
which he read to the Society on the 2">th of January, 1893.3 He
therein brought forward some observations made by him among the
Cuillin Hills of Skye, which he contended finally established the cor-
rectness of his opinion that the granitic protrusions of the Tertiary
volcanic series are older than the gabbros. Instead of trying, how-
ever, to rebut the mass of cumulative proof drawn by me from all parts
of the volcanic area, that the granitic bosses are younger than the
other rocks because they break through thorn and send veins into
1 Quart. Journ. Geol. Soc. toI. xIt. p. 187.
a Op. cit. toI. xlvi. (1890) p. 353. 3 Op. cit. vol. xlix. p. 175.
Digitized by Google
Vol. 50.]
ACID ROCKS OP THE INNER HEBRIDES
them, he ignored that overwhelming evidence, not making even an
allusion to its existence, and proceeded to refer to a single locality,
one which I had specially cited as affording ample proof of my
statements, hut where he affirmed that he had found blocks of
Tertiary granite in the gabbro. The occurrence of these blocks, ho
actually affirmed, now settled the ijuestion beyond further dispute
in his favour. In the debate that followed the reading of the paper,
adverting to this extraordinary method of reasoning, I affirmed that
the structures described by him as occurring in his inclusions'
seemed rather to point to intrusive veins, but that even if the
* inclusions ' were actually detached and enclosed blocks, they could
not justify the sweeping deduction that he drew from them, and
could not for a moment be held to invalidate the copious evidence
brought forward by me from the whole volcanic region, and even
from the very locality now in question, that the acid rock actually
cuts through the basic masses. Even if the so-called 4 inclusions '
were enclosed blocks of granite, how could Prof. Judd suppose
that a few such blocks from one little ridge were to disprove the
definite testimony of scores of sections cited from all parts of the
region ? I contended that until that testimony was examined and
disproved it was idle to bring forward such statements and reasoning
as appeared in his paper.
Possibly I might once more have remained content with a verbal
reply printed in the report of the debate in our Journal. But, while
his paper was passing through the press, Prof. Judd added a
postscript wherein he expressed himself in such a way as to leave
me no choice but to defend my fair fame. He says that he omitted
all reference to " the alleged existence of veins proceeding from the
granite into the gabbro" from " a desire not to complicate the very
definite issue raised in the title of this paper." One would suppose
that less complication would have been likely t o arise had he refrain c<l
from introducing a fresh kind of evidence and a novel mode of argu-
ment until he had disposed of the definite statements already opposed
to him. He then asserts : " I can onlv add that, since this assertion
[that veins of granite cut the gabbro] was made, I have revisited
all the localities referred to, but have never succeeded in finding
true granite- vein s penetrating the gabbro. It was, in fact, while
vainly engaged in searching for such veins that I discovered the
very conclusive evidence of the inclusions described in this paper.
It appears to me that the existence of these inclusions of granite in
the gabbro is absolutely irreconcilable with the occurrence of veins
of the same granite cutting through the gabbro." 1
In consequence of these remarks, though I felt that they could be
conclusively answered at once, I deemed it best to re-examine the
locality in Skye before making any reply. I have since traversed
the ground very carefully, and I now lay the results of this re-
examination before the Society.
I propose to show that my published account of the relations of *
1 0/,. vif. p. 104.
Digitized by LiOOQle
216 SIR ARCHIBALD GEIKIE ON THE BASIC AND [May 1894-
the gabbro and granophyro at Meall Dearg, in Glen Sligachan, Skye.
which is disputed by Prof. Judd, was accurate : that the granophyre
(or granite) there sends abundant dykes and veins into the gabbro ;
that Prof. Judd's so-called * inclusions ' are, as might have been
surmised, portions of these dykes and veins ; and thus that the
evidence which he has adduced affords additional and crushing
testimony to the truth of my observations. When he was opposing
the deliberate statements of a previous observer, it was surely his
bounden duty to examine the alleged facte, on the ground, with
sciupulous diligence. I regret that I must now show that he has
failed in this duty, for, had he used even the most ordinary care, it
is incredible that he could have missed the evidence on which 1
relied. That geologists may be able to judge between us, I have
had some of the visible sections photographed, and I appeal to the
impartial testimony of the camera in ray favour. The evidence from
this Skye locality is so abundant and conclusive, and the point to be
proved is so simple and elementary, that I cannot help feeling as if
some apology were due to the Society for the necessity of bringing
the subject before it.
II. Thk Gabbro Bosses.
The tracts of gabbro among the Western Isles have not yet been
traced out in detail upon maps of a large scale. Until that task is
completed it will hardly be. possible to show how complex these
areas are, alike in their tectonic and petrographical features. I
have referred to this complexity in my memoir already cited, and
have given the evidence which indicates that the larger bosses were
probably the results of many successive protrusions.1
The ridge referred to by Prof. Judd as Druim an Eidhne, the
site of his * inclusions/ is marked on the 6-inch Ordnance map as
forming the south-eastern portion of a rugged spur which, descend-
ing from the crags overlooking Harta Corry, is crossed by the foot-
path to Coruisk. On the map accompanying his paper Prof. J udd
inserts his 4 enclosures ' only on that limited portion of the ridge,
but he would have found that the evidence on which he relied
extended much beyond the narrow limits to which he has restricted
it. Indeed, the most striking evidence of the occurrence of granitic
material within the area of the gabbro lies to the north of these
limits.
The whole ridge which ascends from the hollow of Strath na
Creitheach between the two lochs, and, including the Druim an
Eidhne, rises Into the rugged ground that bounds the eastern side
of Coire Riabhach, affords an admirable illustration of the really
complex nature of the gabbro bosses. Instead of being composed
of one rock belonging to one great interval of eruption, it includes
at least five varieties, exclusive of the granophyres, indicating a
succession of emissions. These rocks are not disposed at random,
but exhibit a certain roughly-bedded arrangement. Conspicuous
1 Trans. Roy. Soc. Edin. vol. ixxv. (1888) p. 140.
Digitized by LiOOQle
Vol. 50.]
ACID ROCKS OF THE INNER HEBRIDKS.
217
are the alternations of a dark, fine-grained, massive rock, which
under the microscope shows a gabbro-like structure, with remarkably
banded and much coarser varieties of gabbro. These varieties of
rock follow each other in rude beds, which run in a general N.N.W.
direction. I shall on another occasion describe in more detail the
remarkable structures of the banded gabbros, which have a suggestive
bearing upon the origin of the structures in some of our oldest
gneisses.1 It may be sufficient to state here that the banded sheets,
as well as those of finer material with which they ore intercalated,
have a general easterly dip, but sometimes curve round so as to incline
towards S.S.E., the angle of dip being usually above 20° (see fig. 1,
p. 222 ). The remarkable segregation of the component minerals of
these banded sheets into lenticular laminae gives them a strikingly
gneiss-like aspect (PI. XIII.). This structure continues up to the
very edge of the granophyre, where it is abruptly truncated.
These rudely bedded and banded gabbros arc traversed by veins
and sills of a remarkably coarse and massive form of gabbro.
Another abundant variety consists of pale, more felspathic material,
which, tuking the form of veins and strings, traverses all the other
gabbros. These pale veins obviously belong to the gabbro series,
to which, under the microscope, their affinity is abundantly clear.
They are the * white veins ' referred to by Prof. Judd in his post-
script as easily distinguishable from apophyses of a granite. But
they are not the veins described by me as proceeding from the
granite (or granophyre) at this locality.
One of the most remarkable constituents of the gabbro ridge iR a
large mass of coarse agglomerate, which forms a group of knolls and
crags among the gabbros, its eastern margin being truncated by the
tolerably straight boundary of the granophyre. It contains abundant
blocks of various slaggy lavas like those of the basalt-plateaux.'*
I)ykes of fine basaltic material intersect the agglomerate and the
gabbros.
1 In various paper* Prof. Judd has repeatedly asserted that I went so far
wrong in my work among the volcanic rocks or' the Western Isles as to mistake
the gabbros for Lauren tian gneiss. My error never went further than a
suggestion, which, however, 1 thought at the time probable. The suggestion
was made in a very guarded way in a footnote on p. 210 of the first edition of
my ' Scenery of Scotland,' published in 1866 : — ' If the hyperathene nick of the
Cuillin HHls of Skye belongs to this ancient formation ' [L.iurentian gneiss]. I
had never had an opportunity of carefully studying the rook, and therefore never
described it in any of my writings. But I had in my early years iu Skye crossed
some parts of it, and had been astonished by its gneiss- like aspect. Any geo-
logist who is familiar with the Lewisian gneiss, and sees for the first time the
banded gabbros of the Cuillin Hills, will readily appreciate how I should have
been led from only cursory examination to connect the gabbro with metamorphic
rocks. The publication of Prof. Zirkel's paper iu 1871 (Zeitachr. Deuts h. ge<il.
Gesellsch. vol. xxiii. p. 1)— that is, three years before Prof. Judd entered the
ground— completely satisfied me that the gabbros were part of the Tertiary
volcanic series.
a There are probably many scattered masses of agglomerate among the Cuillin
Hills, which will be found when the ground is mapped in detail. There must
be at least one in the ba^in of ilarla Corry, and a mass of the rock occurs at
the head of Corry na Creiche.
Q.J.G.S. Ho. 198. q
Digitized by LaOOQle
218 8IR ARCHIBALD OEIKIE ON THE BASIC AND [May 1894,
Thus the important fact is established that the ridge of which
Druim an Eidhne forms part consists of a varied group of volcanic
rocks belonging, not to a single eruption, but to a succession of
eruptions. All these various constituents of the ridge successively
abut against the edge of the granophyre. Each of them in turn is
abruptly truncated along the line of contact with the acid material.
This truncation is made particularly distinct by the way in which
the parallel structure of the banded gabbro?, which so much
resembles lidding, is sharply cut off. The ends of the beds and
lamina? disappear as suddenly as the ends of a series of shales
traversed by a basalt-dyke (fig. 1, p. 222).
It is inconceivable that this truncation could ever have taken
place had the gabbro been an intrusive mass erupted through the
grauophyre. It can only be explained in one or other of two
ways : either the granophyre has been faulted against the complex
basic assemblage of the ridge, or has broken across it as an eruptive
protrusion. The supposition of a fault is at once negatived by the
most cursory examination of the ground, as will be seen from the
evidence which I now proceed to state.
III. Tni? Granophvre Bosses.
There can be no doubt that though, on the whole, simpler in
structure and more uniform in petrography than the gabbros, the
acid bosses are more complex than their external conical forms
would lead us to suspect. Even within the limits of a single con-
tinuous area, like that of the Red Hills of Skye, indications may be
found of successive protrusions of material, not always of precisely
the same lithologicnl character. ]Jut until the structure of the
ground has been traced upon large-scale maps no satisfactory account
of these details can be given.
The granophyre mass which abuts against the great ridge of basic
rooks above described may be taken an fairly typical of the Tertiary
acid protrusions of the Western Isles. It rises northward into the
prominent height of Meall Dcarg (the red rounded hill), which from
the north seems to close in the upper end of Glen Sligachan, and
owing to its bright reddish -yellow colour offers a striking contrast to
the dark gabbro crags that rise behind it and on either side. The
line of junction between the acid and basic rocks, so far as it can
bo observed, is vertical. This is best seen in the ravine which
descends from the western \houldcr of Meall Dearg into the mouth
of Harta Corry. To the south of Meall Dearg the basic rocks rise
as a low, rugged, sometimes mural, crag from the summit of the
long talus of broken-up granophyre, and seen from a distance
presont the deceptive appearance of an overlying cake.1 A little
careful search among the debris and projecting knobs of rock along
1 It was, I have little douht, such 8??tions ns this that gave the impression
that the granitoid rocks underlie nnd are older than the gabbros. But if.
instead of looking at the rough mountains from a distance, a geologist wili
climb their sides, he can easily satisfy himself as to the true nature of the
junction-lino between the two rocks.
Digitized by LiOOQle
Vol. 50.]
ACID ROCKS OF THE INNER UEBRIDKS.
21!)
the base of the cliffs shows that the verticality of the junction- line
continues southward. The same relation can be followed on the
opposite side of Strath na Creithcach and along the precipitous front
of Garbh-bheinn.
Tho rock of Me all Dearg ond of the declivities lying to the south
of that eminence displays the drusy, raicropegmatitic structure so
characteristic of the granophyres of the Inner Hebrides. But one
new feature of interest has been observed in it which deserves
mention here. "While examining under the microscope some thin
sections of this rock, Mr. Teall has discovered that it contains the
mineral riebeckite. At ray request he has been so good as to draw
up the following note on the subject : —
" The rock is medium-grained, light-coloured, and contains drusy
(miarolitic) cavities. The principal constituent is a micropegraatitic
intergrowth of quartz and orthoclase, but more or less idiomorphic
crystals of the same minerals occur. The felspathic portion of the
micropegmatite, which usually surrounds the idiomorphic orthoclase,
extinguishes simultaneously with the central crystal. There are
smali irregular patches, opaque or nearly so by transmitted light,
and brown by reflected light. These may represent in some cases
corroded biotite. Extremely thin opaque black plates (? ilmenitc)
and riebeckite are tho only other minerals present, and these appear
sparingly.
"Tho riebeckite occurs in the well-known spongy forms, and
sometimes as idiomorphic crystals, or rather as crystals which are
idiomorphic in the prismatic zone. The usual forms are those of
the prism {110}, but in one case the cliuo-pinacoid {"10} was also
observed. The a axis is most nearly coincident with the vertical
axis, and the pleochroism is as follows : —
a and ft deep blue ;
y greenish brown.
" Sauer gives green as the colour from rays vibrating parallel to y,
and Harker brown. The determination of the colour in this case
would probably vary with different observers and with the thickness
of the section ; but there can be no doubt as to the presence of an
olive-green tinge in this mineral when viewed by rays vibrating
parallel with y."
As may be commonly observed among intrusive rocks of all ages and
compositions, the granophyres of the Inner Hebrides become finer-
grained towards their margin. They assume sometimes even a felsitic
texture and exhibit flow-structure and well-developed spherulites.
These characters occur altogether independently of the nature of the
adjoining rock. Thus in Mull they may be seen where the acid
rock impinges upon the bedded lavas of the plateaux and upon the
intrusive gabbros. In Kaasay they are well exhibited where the
protrusions have taken place among Jurassic sandstones and shales.
Such well-known phenomena of contact are often of service in
distinguishing truly intrusive rocks.
Q 2
Digitized by Google
220 MB ARCHIBALD GEIXIE ON THE BASIC A1TD [May 1 894,
These marginal structures are exhibited along the whole length
of the junction-line of the granophyre with the basic rocks of the
ridge from the western slopes of Meall Dearg southward. The
granophyre, as it approaches that junction-line, becomes fine-
grained or felsitic in texture, showing here and there abundant
spherulites ranged in rows along the lines of flow-structure, which
are sometimes remarkably well developed and run parallel with the
edge of the rock. In the ravine on the west side of Meall Dearg,
where the vertical line of contact between the basic and acid rocks
has been so well exposed, the perpendicular rows of spherulites run
up the bare faces of granophyre.
It is important to observe that, at this locality as elsewhere,
no dependence whatever can be found between these marginal
structures in the granophyre muss and the various rocks of the
ridge against which they abut. The spherulites, for instance, are
to be eeen just as well in the acid rock where it impinges on
the agglomerate as whero it lies next to coarse massive gabbro.
There is, indeed, nothing unusual in this feature ; on the contrary,
it is exactly what any geologist acquainted with the behaviour of
intrusive bosses would have expected. Prof. Judd speaks of having
observed the spherulitic structuro and felsitic texture " at one or
two points" along the junction-line of the basic and acid rocks, but
he makes no further reference to this observation. He apparently
groups these marginal structures with those of his * inclusions,'
regarding them as due not to the more rapid cooling of the outer
shell of the granophyre, but to the re-fusion of that rock from the
protrusion of the gabbro through it Whether fusion on so large
a scale could have been effected in a solid mass of granite by the
breaking through it of a continuous body of gabbro is obviously open
to grave question. To assert that structures which are common
characteristics of the marginal portions of bosses, sills, aud dykes
are in this instance produced by re-fusion, and thus that what by
the ordinary laws of evidence would be set down as the older rock
is here really the newer, surely demands specially cogent and
copious proof. But even if we grant that a large mass of gabbro
disrupting a previously solidified granite might possibly induce upon
it these marginal structures, is it conceivable that a complex
assemblage of basic rocks, successively injected in thin sills and
narrow dykes through each other, such as I have shown to con-
stitute the ridge north of Druim an Eidhne, could have produced such
effects ? Is it to be supposed, too, that the agglomerate exercised
the same melting influence on the rock next to it, which, as I have
shown, presents just the same structures ? In short, even were
there no other evidence than this fine-grained felsitic and spherulitic
margin, this, I submit, would be in itself sufficient to prove that
the granophyre has broken through the gabbro.
The structures so well exhibited on the periphery of the grano-
phyre are not, however, confined to that part of the mass. On
the rocky slopes south of Meall Dearg, close to the edge of a gully
cut by the southern fork of the stream which drains that hillside, a
Digitized by LiOOQle
Vol. 50.]
ACID ROCK 3 OF THE INNER HEBRIDES.
221
prominent rib may be observed rising amid the ordinary granophyre.
It consists of a spherulitic fine-grained material forming a band
about 10 feet broad, which may be traced under the debris for
several hundred yards up the hill in a direction slightly north of
west. It exhibit* the same beautiful flow-structure with spherulites
as is seen in the marginal part of the granophyre boss. The
spherulites, often an inch or more in diameter, are set in rows
along the lines of flow-structure, which run parallel to the direction
of the rib. Tho absolute identity of these structures with those
which I have described and with those also of the dykes and veins
to be immediately referred to, including those of the so-called * in-
clusions/ is so obvious that there cannot be any room for hesitation
in classing them all together as having oue common origin. The
presence of a band of spherulitic granophyre or felsite in the main
body of tho granophyre, at a distance of 1000 feet from the edge of
the gabbro, cannot be accounted for by any f usiug effect of the basic
rock. Like the marginal zone of finer grain, this internal dyke-like
rib obviously represents a phase in the consolidation of the great
protrusion of acid material, though its production may have been
somewhat later than that of the marginal zone and its offshoots.
I now proceed to show that the great granitic eruption of Glen
Sligachan has been accompanied by the injection of dykes and veins
iuto the adjacent rocks, as formerly affirmed by me. About half a
mile south from tho top of Meall I)earg, and thus well to the north
of the locality at which Prof. Judd has shown the position of his
' inclusions ' on his map, the low gabbro cliff, where it overlooks the
sources of the streamlets that run down the declivity below, is
interrupted by several hollows which allow of an easy ascent to the
summit of the ridge. On examination it is found that theso inter-
ruptions in the line of cliff are duo to breaks in the continuity of the
various beds and veins of different gabbros, and to the divergence of
dykes of granophyre from the main body of that rock. Three such
interruptions may be observed within a horizontal distauce of
90 yards (fig. 1, p. 222). Each of these marks the position of a dyke
which can be followed from the spherulitic margin of the granophyre
with which it is continuous and of which it forms an offshoot.
The most northerly of the three dykes (I.) is about 0 feet wide
where it issues from the main mass of granophyre. Weathering
more easily than the basic rocks through which it runs, it occupies
the bottom* of a long hollow of which the various sheets of gabbro
form the craggy sides. But it protrudes at numerous points from
under the turf, and by means of these projections can be followed
in a nearly straight line in a S.S.E. direction for 800 feet, when it
is lost beneath herbage and masses of gabbro.
The second dyke (II.), from 0 to 8 feet broad as it leaves the
granophyre mass, runs parallel to the first at a distance of about 30
yards from it, and can be traced for 200 feet or more southward
across the gabbro. There is in this case also no difficulty in
iollowing along the line of straight hollow the protruding knobs,
Digitized by Google
222 8IR ARCHIBALD GEIKIE ON THE BASIC AND [^ay 1 894,
which display the most exquisite spherulitic structure, up to the last
visible exposure.
The third dyke (III.) lies about 12 yards east of the second.
I traced it for about 40 feet, and then lost it in the rough gabbro
ground. But, even where not visible at the surface, some of theso
dykes may be persistent underneath, and may not improbably come
to the light again farther south as the detached bands (' inclusions ')
of felsitic and spherulitic material to which I shall afterwards
allude.
Fig. 1. — Plan of a portion o f tht rkl(j( north of Druim an Eidhne,
south of Glen Slvjachan^ Slcye.
a. Gabbros; b, granophyre ; I., I show the direction of dip of the
H.| III., three dykes proceeding bands of gabbro.
from the granopbyre. The arrows J
That these three dykes are apophyses of the large bodv of grano-
phyre of Glen Sligachan admits of no question whatever. As a
Digitized by Google
Vol. 50.]
ACID ROCKS OP THE INNER HEBRIDES.
223
demonstration of this assertion I produco a photograph (PI. XIV.)
of the second example (II). The camera, when this view was
taken, was planted on the main mass of granophyre which, with its
marginal lines of flow-struetiire and rows of spherulites, could bo
followed up into the dyke. The vertical walls of the dark-banded
gabbros are here clearly exhibited, with tho pale dyke of acid rock
rising between them.
But it is not enough to say that tho granophyre sends apophyses
into the gahbro. The fact of the intrusive character of tho acid rock is
rendered still more striking by the arrangement of the various beds
and veins of the complex mass of basic materials across which tho
dykes have been intruded. In fig. 1, wherein I have tried to
express diagrammatically the purallel banding of the gabbros, it will
be seen that the successive basic sheets, dipping in a south-easterly
direction at from 20° to 35°, are cut througli by the dykes. Thero
is thus a double truncation of tho bedding and banding of tho
gabbros. These structures are abruptly cut off by the vertical wall
of the granophyre boss in a general \V.N.\V. direction, while they
arc further intersected in a N.N.W. direction by the dykes. No
more conclusive evidence could be given of the fact that tho grano-
phyre has been protruded after tho last of the successive eruptions
of gabbro.
I have instanced first some cases of apophyses which can actually
be seen to diverge from the granophyre mass of Meall Dearg. But
there are numerous veins and dykes of exactly similar material
which traverse the various recks of the gabbro ridge, but of which
the direct connexion with the main body of tho acid rock cannot bo
observed. These detached poitions may be seen all over the ridge,
and even on its western front, looking down into the deep hollow of
Coiro Kiabhach. They lie between the dykes I have described and
the Druira an Kidhne, where they are frequent, continuing south-
ward beyond the Uoruisk footpath. Except that they cannot bo
directly traced to the granophyre aud that their visible portions aro
comparatively short, many of them are in every respect repetitious
of the dykes which cau be seen to issue from the body of the acid
rock. Indeed, it seems to me probable, as above suggested, that
some of them are really prolongations of these dykes, rising onco
more to daylight. But that, in any case, they aro true veins or
dykes of later date than the basic materials amid which they lie is
abundantly manifest from their form, their internal structure, and
the manner in which they intersect the surrounding rocks.
These detached masses are long aud narrow strips, like the dykes
just described. They vary up to G or 8 feet in breadth, and can bo
followed continuously for variable distances, often for 20 feet or
more. They display, exactly as the dykes do, a fine-grained texturo,
beautiful How-structure, and rows of spherulites. Moreover, the
flow-lines follow faithfully the irregularities of the bounding walls
of gabbro, curving round projections with the sweeping and some-
times curling lines so characteiisticof rhyolitic streams. Nowhere,
Digitized by Google
*04 8IR ARCHIBALD OEIKIE OK THE BASIC AND [May l894,
"Tow"^ wS^^od, but is nevertheless true, that
details the structures of the dykes which can ne tr _ ,
rtr\XT5VuYd9 a hT sV - «.
described by rrot. juuu. a» .,*„,ks of "a number of
•inclusions' is somewhat vague "depressions in the
parallelism of their now-structure and ^^^^Tdww-
bounding walls ; nor does he seem to hi aw tn" followed as
iug "a section of several ^.Sts Kven the mallest of
including Dru.m an t.dhne Ihere must d ^ rf
fen'^Terc'^fludd oWrvl them! a'nd on the little portjon
In Eidhne where he has marked them „„ h,s map , b
for some hundreds of yards across the r.dge along its wh»le.«e«
of a mile or more. In fact, the ridge is penetrated by many protru-
sions of the acid rock, and it is the ends ^.P^^L^
veins and dykes, visible at the surface, which Prof. Judd has
mistaken for inclusions. , —\,i*h will
Let me describe two or three illustrative ^"P1^,^
serve to show the various aspects of these apparently detached
portions of the great acid intrusion. At the point where the toot-
path to Coruisk begins to ascend the rugged gabbro nuge, u . »
crossed by a small stream, and at this locality a well-marked vein
of felsitic rock runs through the gabbro. If the observer turns
northward from this point, up the craggy surface of Drurni an
ttidhne, ho will, at a distance of about a hundred yards, come upon
another vein, varying from 1 to 3 feet in breadth, traceable tor
20 feet, and exhibiting the most perfect flow-structure, parallel
to the walls, with rows of large, and sometimes hollow, spheruhtes.
A few yards farther up the hill, another exposure (which may be a
further portion of the same dyke) displays the relations represented
iu fig. 2 (p. 225). The portion of the dyke visible is about 18 feet
long and 6 feet broad. The rock is a fine granular felsite or close-
grained granophyre, with exquisite flow-structure, which not only
keeps parallel to the boundary-walls, but follows all their irregu-
larities of contour, its lines curving round projections and sweeping
into cddy-likc swirls, in such a manner as vividly to portray the motion
of a viscous lava flowing in a cleft between two walls of solid rock.
Digitized by LiOOQle
Vol. 50.]
ACID ROCKS OF THE IN.VER HEBRIDES.
225
Sometimes the laminaj of flow have been disrupted, and broken
portions of them have been carried onward and enveloped in the
still unconsolidated material. Some portions of the dyke are
richly spherulitic, the spherulites varying from the size of small
peas up to that of tennis-balls. Occasionally two large spherulites
have coalesced into an 8-shaped concretion. In its flow the acid
rock has caught up and enclosed portions of the gabbro walls. Iu
fig. 2 one such block is shown with the lines of flow sweeping
round it. Another portion of gabbro at the right hand of the figure
may be a projection of the wall, but is more probably a second
enclosed block. I did not, however, trace the felsite completely round
its northern end.
Fig. — Plan of granophyric dyke cutting and enclosing gabbro,
Dntim an Kidhne^ Skye.
I have had thin slices cut from the gabbro-block enclosed within
this dyke, and have submitted them to microscopic examination by
Mr. Teall, who has been so good as to furnish me with the following
memorandum regarding them : — " The rock is medium-grained, dark
green, and massive. Its principal constituent is a turbid plagio-
clase, which sometimes shows a tendency to assume rectangular
forms. The ferro-magnesian constituents occur in greenish or
yellowish -brown patches, which sometimes have the form of the
augite in the ophitic gabbros and sometimes have ill-defined bound-
aries, owing to the fact that the substances of which they are com-
posed penetrate the surrounding plagioclase. Those patches consist
partly of uralitic hornblende and partly of an extremely fine
aggregate into which mica probably enters as a constituent. Quart/,
magnetite, and apatite also occur in the rock, which is evidently an
altered gabbro."
The alteration which the material of this block has undergone
is such as might naturally be expected to occur in a lump of
gabbro enclosed within a mass of eruptive rock. But as it might
Digitized by Google
226 SIR ARCHIBALD GF.IKIE OS THE BASIC AND [^aV 1894,
be accounted for from other causes I do not lay any stress on its
occurrence.
On the western declivity of the gabbro ridge, a little south of the
summit, the gabbros are traversed by a well-marked dyke or veiu,
which is represented iu fig. 3.
Fig. 3. — View of ftlritie dyke cutting gahbro (west tide below
hiyher part of rubje, north of Druim an Kirf/nie, Skye).
It is from 8 to 12 inches
broad, and is traceable tor
about 28 yards. It dif-
fers from the broader
dvkes both in form and
in internal structure.
Instead of weatheriug
into a long hollow, it
stands up as a sharp rib,
which, from its lighter
colour as well as its pro-
minence and persistence,
can readily be distin-
guished, even at a dis-
tance, from the dark ba>ic
rocks around it. The
rock comprising this dyke
is a dull purplish-grey
felsite, weathering with
a pale-bluish surface. It
is specially marked by its
well-defined lines of flow-
structure, which, as thin lamina? parallel with the bounding walls,
cause the rock to weather into slabs.
South of the group of dykes shown in fig. 1 (p. 222), and a little
west of the mass of agglomerate, a dyke of quartz-felsite may be
obFerved traversing the gabbros and demonstrating its intrusive
origin by the branches that diverge from it. A portion of this
dyke is represented in fig. 4 (p. 227). It is about 1 foot broad, and
the portion shown in the figure is 9 feet long. The rock con-
sists of felsite containing double pyramids of quartz. It gives off
small veins, 4 or 5 inches or less in width, which run as wavy
ribbons for some yards through the basic rock, and die out in mere
threads. Thus, while the broader dykes, like the marginal portions
of the main body of granophyre, show flow-structure and spherulites
on a great scale, these structures grow finer as the injected portions
of acid rock diminish in size, until they cease to be visible.
It is not necessary to cite more examples from this locality. I
■will only say that veins and dykes of the acid material are not con-
fined to the immediate proximity of the visiblo mass of granophyre.
They may be observed traversing the dark crags of gabbro even up
Digitized by Google
Vol. 50.]
ACID ROCKS OF THE INNER HEBRIDES
227
to the crests of the Cuillin Hills, and on the western front which
plunges into the dark cauldron-like hollow of Corry na Creiehe they
likewise occur. In Bhort, as I have shown ekewhere, the gabbro
masses as well as the plateau-lavas are penetrated by a vast number
Fig. 4. — Plan of quart z-f el site dyke and veins traversing yabbro
{n est of Druim an Eidhne, iShye).
of felsite-veins and dykes. There must be an immense body of acid
material underlying the vurious rocks that surround the granophyre
bosses, these bosses being merely its upper visible projections.
IV. Conclusion.
The evidence which I have adduced in the present paper will, I
trust, establish beyond any further cavil or question the fact, about
which there really ought never to have been any dispute, that the
great granophyre bosses of the Inner Hebrides are of younger date
than the gabbros. Prof. Judd considers the determination of
the relative ages of these two groups of rock to be an ** absolutely
crucial " point in the interpretation of the volcanic history of the
region. And in this judgment I entirely agree with him. Hut,
apart from its local importance, the question has much wider
bearings hi regard to geological theory, and especially to an under-
standing of the sequence of volcanic roeks. Many examples are
now known of the ascent of basic material first and of acid material
last in a cycle of volcanic activity, and this sequence harmonizes
well with the known order of separation of the constituents in
deep-seated bosses of eruptive material. The magnificent cones as
well as dykes and veins of granophyre which have burst through
not only the basalt-plateaux but also the eruptive cores of gabbro,
all over the range of the Western Isles from Mull to St. Kilda,
present the noblest example of this sequence in our area.
In fine, there is a featuie of Prof. Judd's paper which for
628 SIR ARCHIBALD GEIKIE OK THE BASIC A3fD [May l80A,
the sake of the progress of geology I sincerely regret. Though
doubtless much has still to be learnt regarding the behaviour of
eruptive masbes of igneous rocks, there are certain phenomena of
which so many examples have been observed that they are generally
considered to be well established. Among these phenomena are
the folaitic, spherulitic, and flow-structures which are found in
lavas and in the peripheral and apophysal portions of deep-seated
bosses, at the margins of sills, and often in the body of dykes and
veins. These structures have been so abundantly noticed under cir-
cumstances pointing to the effects of cooling and consolidation,
that, though some of the details of the processes still need elucida-
tion, the general conclusion has been accepted that the structures
represent stages in the comparatively rapid chilling and solidifica-
tion of molten material. The student who has mastered this part
of tectonic geology, and who has become familiar with examples of
these effects of cooliug among rocks in the field, may well feel per-
plexed when Prof. Judd tells him that these very structures can be
produced by re-fusion and such excessively slow cooling as must
take place within a doep-soated basic eruption ; and that blocks of
granite, several yards in diameter, may in such a position be melted,
and instead of assuming a distinctly crystalline structure, as it
might have been supposed that, under these conditions of prolonged
high temperature and extremelv gradual refrigeration, they would
have done, may acquire a tine felsitic texture, an exquisitely perfect
spherulitic flow-structure, conforming to the surface of the enclosing
material and presenting all the usual signs of true rhyolitic move-
ment. His bewilderment will be still further increased when he
learns from Prof. Judd that this alleged order of change is entirely
borno out by microscopical investigation. He may surely be par-
doned if ho feels inclined to abandon in despair a subject wherein
the testimony of field-evidence and of microscopic research may be
made so entirely to contradict common experience.
Happily the conflict of testimony is not to be found in nature.
I have shown, I think, conclusively that the whole of tho phenomena
in Skye are perfectly harmonious aud intelligible, that they involve
no exceptional occurrences, but that they exhibit in a singularly
clear and striking manner the behaviour of an acid rock which has
disrupted and invaded an older basic group. The literature of
inclusions in igneous rocks cited by Prof. Judd, and his detailed
account of the quartz-felsite fragments of Ascherhubel, though
interesting in themselves, are really irrelevant to the facts observable
at Druim an Eidhne and its neighbourhood. In ihe field he has
missed the clear evidence of the dykes proceeding from the grano-
phvre, and. following his original error, has reversed the true order
of sequence of the volcanic rocks. With the microscope, the in-
fluence of the same unfortunate misreading has led him to iuvert
the actual succession of structures.
The locality in Skyo which he has now brought forward to prove
his contention is only one of many which I have cited in support
of the view that the acid protrusions are among the latest of the
Digitized by L>00j9i£
Vol. 50.]
ACID ROCKS OF THE INNER HEBRIDES.
229
whole series. Having demonstrated in the present paper how fully
my reading of that locality was justified, I confidently appeal to
the vast mass of evidence which is given in ray memoir in the
Transactions of the Royal Society of Edinburgh, as furnishing a
body of proof sufficient to place this question finally among the well-
established facts of British Geology.
EXPLANATION OF PLATES XIII. & XIV.
Platk XIII. Banded gabbro in the Tertiary volcanic series, ridge north of
Druim an Eidbne, Glen Sligachan, Skye. (From a photograph.)
The portion of gabbro here represented is an abrupt face of rock about
7 fe«*t long by .r> feet high. Tbe darker bunds show where the iron ores
and ferro-inagneaian constituents predominate; the paler layers consist
mainly of plagioclase.
Plate XIV. Dyke of granophyre ffi to 10 feet broad) proceeding from the
main mass and interacting the banded gabbro*. (From a photograph.)
The camera, in taking the original photograph, whs placed on the main
body of granophyre from which the marginal spherulitic and flow-structures
can be traced up into the dyke. The dark ma** to the left of the dyke in a
portion of the banded gabbro* lying between the dyke and tho main mass
of granophyre.
Discussion.
The President said that he had listened with much interest to
the reading of Sir Archibald Geikie's paper ; the Author had made
out his case so clearly that no one, it might be supposed, could for
a moment doubt that the interpretation which ho had given was the
correct and the only one ; nevertheless, he had reason to believe that
Prof. Judd had, with careful study, arrived at quite a different view
of these same rocks. No one could doubt the abilities of these
eminent geologists, and he must therefore conclude that the naturo
of the country was such as to render agreement very difficult, and
the possibility of two observers arriving at quite different views,
on the samo ground, extremely easy.
Prof. Jcdd remarked upon the circumstance that the Author's
opening statement, though professing to be historical, entirely
ignored the labours of John Macculloch and J. D. Forbes, who, from
observations made at the very spot treated of in this paper, were
first led to the conclusion that the gabbros of Skye are younger
than the granites.
The speaker entirely agreed with the Author that the gabbro of
the Cuillin Hills consists of n great number of sheet-like intrusions,
sometimes showing the banded structure so common in the granu-
lites. He had, indeed, gone much farther than this, and argued
that these sheets are composed of the materials that had consolidated
in the great ducts or fissures giving vent to the abundant currents
of basaltic lava. He agreed, moreover, with the Author as to the
great profusion of veins which traverse both classes of rock, and in
his conclusion that these are really ' contemporaneous ' or * segre-
gation-veins.' Nor did he dissent from the view that the granites
frequently become fire-grained (' microgranitic ' and 'felsitic') in
the peripheral portions of their mass.
Digitized by Google
230
THE BASIC AND ACID ROCKS
[May 1894,
When the Author added that handed and spherulitic rhyolites
are often found constituting the margins and apophyses of granitic
bosses, he felt, however, unable to follow him : and the statement
that it was such banded and spherulitic rhyolites which form the
dykes, supposed to be apophyses of the granite, suggested to him
grave reasons for doubting the interpretation of the phenomena
put forward by the Author of the paper. The Author had pointed
out the existence of a dyke-like mass of the banded and spherulitic
rhyolite in the very midst of the granite of Meall Dearg, and he had
admitted that this might possibly constitute a later intrusion than
the granite itself. But if this were the case with the rhyolite in
the midst of the granite, might it not also be equally true of the
rhyolite in the peripheral portions of tho same mass ? The granting
of this, however, would at once destroy the argument based on the
statement that the granite itself sends offshoots into the gabbros.
This was only one of several ways in which the appearances might
be interpreted, without accepting the conclusions of the Author of
the paper.
But while there was this uncertainty about the evidence of veins —
and corresponding differences of opinion on the bearings of this class
of evidence had been exhibited among competent observers, in the
case of two previous discussions before the Society, the rival views
being supported by a similar display of diagrams aud photographs —
there could be no doubt whatever as to the evidence of included
fragments. The speaker exhibited hand-specimens taken from
masses which were completely surrounded by the gnbbro. The
centres of these specimens consist of the normal mieropegmatitic
granite (' granophvre ') of the district, the fused outer coating dis-
playing all those phenomena which have been so well described by
Lehmann, Bonney, Sauer, Baekstrom, and other penologists, as
belonging to masses of acid rocks that have been caught up and
enveloped in basic ones. In opposition to the Author of the paper,
the speaker maintained that the demonstration of a single case of
one rock being enclosed in another was proof positive as to their
relative age. With respect to the specimens on which he relied,
and the sections cut from them, he ottered to submit his whole case
to the three ]>etrologists of the Geological Survey — in whose judg-
ment and fairness he had the most perfect confidence.
The Author, in reply, remarked that Prof. Judd had left the
essential part of the paper unanswered. It was beside the question
to bring up the observations of earlier geologists. No amount of
such testimony could avail in the teeth of plain facts. Prof. Judd
had affirmed in his hist pajrcr that the presence of inclusions of
grnnite in the gabbro was absolutely irreconcilable with the
existence of veins of the same granite cutting the gabbro. But it
must obviously be just as true that the presence of dykes of granite
(or granophvre ) cutting the gabbro is absolutely irreconcilable
with the existence of inclusions of the same acid rock in the basic
scries. Prof. Judd had brought forward no evidence that his
4 inclusions ' were really such ; but he (the Author) had adduced in
Digitized by Google
Quart. Journ. Geol. Soc. Vol. L. PI. XIII.
Dyke of Granophyre (6 to xo feet broad) proceeding
t FROM A PHCX
Digitized by Google
Quart. Journ. Geol. Soc. Vol. L. PI. XIV.
-
main mass and intersecting the Gabbros.
Vol. 50.] OF THE INKER HEBRIDES— DISCU33I0X.
231
the present paper overwhelming evidence that the granophyre has
disrupted the gahbros. Photographs wero produced in which the
light-coloured granophyre is seen to rise as a dyke through the dark
gabbros and in which the same structures are displayed as occur
along the margin of the main mass of granophyre and in the
so-called 4 inclusions.' Specimens were also exhibited showing
that in the body of the granophyre, and in the dykes which could
he traced diverging from it, the very same spherulitic and flow-
structures occur which Prof. J udd describes as characteristic of his
1 inclusions.' It had been shown in the paper that these 4 in-
clusions,' instead of being irregular blocks, are really linear veins or
dykes with flow-structure pnrallel to their walls and enclosing
pieces of the surrounding gabbro. It had also been pointed out
that the remarkable banded structure of the complex series of
gabbros is truncated both by the main mass of granophyre and by
the apophyses from it.
The Author had not criticized Prof. Judd's account of the micro-
scopic structure of the material of his 4 inclusions.' He was even
willing to accept it as fairly accurate, with, however, the important
reservation of the alleged proofs of re-fusion. But no amount of
petrographical ingenuity could withstand the plain evidence in the
field that the granophyre sends offshoots across the gabbros. In
the face of this evidence it is mere waste of time and labour to
dispute about points of minute detail.
Digitized by Google
232
DR. J. W. GREGORY ON THE WALDRN81A* [May 1 894,
17. The Waldknsian Gneisses and their Place in the Cottiax
Sequence. By J. W. Gregory, D.Sc., F.G.S., of the British
Museum (Nat. Hist.). (Read February 7th, 1894.)
[Plate XV.]
Contents.
I. Introduction 232
II. The Cottian Sequence and Previous Literature thereon 2M
III. The Gneisses 230
(a) The Paradiso Massif.
(b) The Waldensian Gneisses.
IV. Conclusions a? to the Relations of the Beds 200
V. The Contact-Metaraorphism 'j(»2
VI. The Origin of the Gneuwic Structure 2rt4
VII. The Age of the Waldensian Gneisses 2«7
VIII. Summary of Conclusions 274
Xotc. — This paper was originally sent in to the Geological Society on October
19th. 1892, but owing to the writer's absence from England the reading, and
consequently the publication, have been delayed. No reference is therefore
tuude to some recent papers on this and an adjoining part of ihe Alpe, as
they do not affect the argument.
I. Introduction.
The Cottian Alps consist of three main lines of mountains occu-
pying an area roughly triangular in shape, and forming the extreme
western segment of the great curve of the Western Alps. They
may be divided into three groups: the Northern Cottians, running
K.N.E. and W.S.W.from Roche Melon to Mont Thabor; the Western,
running from Mont Thabor S.E. to Monte Viso ; and the Eastern,
which completes the triangle by continuing the line of the Graions
southward from Kochc Melon till it joins the Western chain at its
southern end. Of these three ridges the Northern and the Western
form the main topographic chain, which connects the group of the
Graians with the chain of the Maritiraes. The arrangement of
these two divisions of the Cottians is, to a large extent, independent
of their geological structure. Thus Mont Thabor is composed of
Carboniferous and Triassic rocks; south-east of this we leave the
Triassic limestones at Monte Chabcrton and pass to the gabbros
and variolitic series of Mont Genl-vre, which are certainly not earlier
than the Upper Mesozoic : to these succeed the calc-schists and
mica-schists, and then a vast series of gabbros, serpentines, amphi-
bolites (epidiorites, etc.), and glaucophane-schists, which extend
from Brie Bouchet to the Viso. Along most of these Western
Cottians the direction of the mountains does not agree with the
strike of their constituent beds ; branches from the main chain run
off along a north-and-south line and show the efforts of the forces
of elevation to adapt themselves to the rock-masses which they were
upraising. Such, e. is the range that forks from the main chain
Digitized by Google
Vol 50.]
GNEISSES IN THE COTTIAN SEQUENCE.
233
to the north of the Col de Traversette and runs from Monte Granero
through Punta Manzol and Funta Agugliassa to Punta Plengh.
This explanation does not, however, apply to the north-and-south
ridges that form the main features in what Mr. Coolidge aptly
describes 1 as 44 the very tangled and little known ranges around
Cesanne."
A comparison of the Eastern with the Western and Northern
Cottians reveals several points of much interest. Thus the two
latter are simple topographically and complex geologically ; they
include rocks of very different ages and characters, from the Upper
Mesozoic or Eocene diabases of Le Chenaillet and the Jurassic lime-
stones of Monte Chaberton to the old eruptives of Monte Viso ; they
have been upraised by earth-movements of considerable complexity,
involving extensive foldings, inversions, and overthrust faults. The
Eastern chain, on the other hand, is complex and inconspicuous topo-
graphically, having been cut across by the valleys of the Waldenses ;
but it is comparatively simple geologically. It is composed essentially
of a series of schists and schistose rocks — possibly bent into an anti-
clinal, with a series of banks of coarse fresh augen-gneiss occurring
along the axis of the fold.
It has been generally agreed that the rocks of the Eastern Cottians
may be grouped into three series, a fundamental Laurentian gneiss
(the 4 central gneiss ' of Zaccagna ") at the base, covered by a double
set of schists, the Upper and Lower Archaean schists of Prof. Bonney 8 ;
these three correspond to the ' gneiss antache,' the ' zona delle
pietre verdi,' and the 4 terreni cristallini stratificati piu recenti ' of
Gastaldi.* This classification and the view of the antiquity of the
basal gneiss has been accepted by all recent writers on Cottian
geology, including, in addition to those already quoted, Baretti,*
Lory, 8terry Hunt,9 Sacco,7 and Gianotti"; by all, in fact, since the
abandonment of the old view of the Jurassic age of the whole series.
This classification, moreover, is in harmony with the almost uni-
versal sequence of the pre-Cambrian schists. M. Michel-Levy has
referred* to the identity in the threefold series in the Central
1 W. A. B. Ooolidge, Alpine Journ. vol. xiv. p. 336.
a D. Zaccagna, 'Sulla Geologia delle Alpi occidental!/ Boll. R. Com. geol.
Ital. toI. xviii. (1887) pp. 346-417, pis. ix.-xi.
' T. G. Bonney, ' note* on Two Traveraea of the CryAtallino Bocks of the
Aloe,' Quart. Journ. Geol. Soc. vol. xlv. (1889) pp. 07-100.
* B. Gastaldi, ' Studii geologici sulle Alpi occidentali,' pt. i. Mem. deecris.
Carta geol. Italia, vol. i. (1871) pp. 1-48, pla. L-vi. ; pt. ii. ibid. vol. ii. (1874)
pp. 1-61, pi. i.
' Baretti, * Studii geologici sul gruppo del Gran Paradiso,' Atti B. Aocad.
Lincei, ser.3, Mem. vol. i. pt i. (1877) pp. 195-313, 7 pla.
4 T. 8. Hunt, 'Gastaldi on Italian Geology and the Crystalline Rock*,* Geol.
Mag. 1887, pp. 531-640.
7 F. Sacco, * La Geo-Tectonique de la Haute Italie occidentale,' Mem. Soc.
Beige Geol. Pal. Hydr. vol. iv. (1890) pp. 3-28, pi. i.
* G. Gianotti, ' Appunti geologici Bulla Valle di Chialamberto (Valle di
Lanao-Alpi Graie)/ Boll. Soc. geol. Ital. vol. x. (1891) pp. 149-107, pi. v.
* Michel-Levy, 'Note aur la Formation gneifwique du Morvan et Comparaiaon
avec quelquea autre* regions de mime nature,* Bull. Soc. geol. France, aer. 3,
vol. vii. (1879) pp. 862-860.
Q.J.G.B. No. 198. a
234 DR, J. W. GKF.OOKT OX TDE WALDEN8IAN [May I094,
Plateau of France, Britanny, and the Western Alps (Oisans), in
Switzerland as at the Simplon, in {Spain as in Cantal, in Germany
as in the Eulengebirge and the Oberpfalzerwaldgebirge, and also
in Canada. The same series, basal gneisses, then coarse gm-issose
mica-schists with amphibolites and upper less foliated schists and
phyllites, can be followed even farther than M. Michel- Levy has
done; it occurs in China, as described by Kichthofen,1 and more
recently by Vclain,* who has pointed out the close resemblance of
the gneiss to that of the Simplon. In Brazil the same sequence
occurs, on the authority of Hartt3 and Sterry Hunt ; in Tasmania,
as described by Thureau* ; in India6 it is represented in the Sub-
Himalaya by the central gneiss, the gneissose schists and foliated
slate series, while in some places, as around Sikkim, the middle
member of the 4 Daling ' series contains many hornblendic schists.
In Scandinavia occurs tho similar sequence of ' jern gneiss ' (with
magnetite), and 4 gneiss gris a grenat,' or common gneiss with am-
phibolites, with overlying phyllites ; in Finland the succession is
the same, and Lucas " compares it with that established by Profs.
G umbel, Groth, and Bonney in Saxony, the Vosges, and the Alps
respectively.
In all these localities the sequence is fundamentally the same, the
only variation being in the position of the amphibolites, though
these are always confined to the two upper divisions.
Whilo the accepted theory of the structure of the Cottians num-
bered among its advocates practically all recent writers on the
subject, and as it was iu harmony with this almost world-wide
sequence, it appeared rash in the extreme to doubt its truth. Two
previous visits to the area and a study of its literature and maps
had, however, raised several difficulties which appeared insuperable.
If the gneiss were the oldest rock in the district., why had it cscaj>ed
tho crumpling and contortion, the foldings and faulting to which
the other rocks have been so extensively subjected ? Why arc its
minerals so fresh when those of the schists around are so weathered
and altered ? Why does it happen that the mica-schists near the
gneiss are generally so much coarser than at a distance, and so
frequently garnetiferous ? Again, if the gneiss is the oldest rock,
why have none of the intrusive sheets and dykes of serpentine and
amphibolites of the * pietrc verdi ' series ever penetrated it? They
cut through all the other rocks, from tho Mcsozoic limestones to tho
1 F. ron Richtliofon, ' Cliinn,' vol ii. a 882) p. 70fl.
7 Vt lnin. ' Grologio de la Chine,' Bull. Soc. geol. France, ser. 8, vol. ix.
(1881) pp. 474- 47.").
* C. F. Hartt. ' Geology and Physical Geography of Brazil,' 1870, pp. 550-
551.
4 Thureau, 4 Tasmania — West Coast, Progrea* Reports of Mine?, no. 2:
Mount Huetnskirk and it* Minernl Deposit* and Mine*,' Tasmaniati Pari.
Papers, 1881, no. 82; and Johnston. 'Geology of Tasmania,' 1888, p. 23.
4 Medlicott in • Manual of Geologv of India,' 1870, pt.ii. pp. 014. rtltf. C>27.
• R N. Lucas. 'Notes on the Older Rocks of Finland,' Geol. Mag. 1891,
pp. 173. 174 ; see al*o Sederhohn. ' Studten liber urchaischer Erupt ivgesteine »us
dem sudwrstlichen Finnland,' Tacheriu. Pelr. u. Miu. Mitth. vol. xii. (1891)
pp. 98-100.
Digitized by Google
Vol. 5o.]
GNEISSES IN THE COTTIAN SEQUENCE.
235
lowest mica-schists : they approach very close to the gneiss, bat
never enter it. Gastaldi's map 1 of the Paradiso, on the contrary,
actually shows one broken across by the gneiss (fig. 2, p. 240). In reply
to the enquiry as to whether any case were known of an intrusion of
the 4 pietre verdi ' series into the central gneiss, Prof. Saoco assured
me that such is impossible, as the occurrence of one of this scries in
the gneiss would prove that this belongs to the newer gneisses,
(jastaldi, who fully recognized both the fact and its significance,
boldly claimed a that this proved that the ' pietre verdi ' rocks were
not igneous but bedded sediments : if they were intrusive, he argued,
they would certainly have somewhere cut the basal gneiss. There
seemed, however, another alternative, viz. that the central gneiss
may be newer and not older than the overlying schists ; Gastaldi
does not appear to have considered this explanation, which was not
opposed to any of the facts known to me. Prof. A. C. Lawson's
remarkablo work on the geology of Rainy Lake,* proving that tho
4 Laurentian ' gneiss was there intrusive into the overlying rocks
which have been correlated with the Huronian, showed the possi-
bility of the truth of this explanation. Prof. Lchmann ' and Dr.
Danzig's * confirmation of Naumann's view of the intrusive nature
and post-Archaean age of the Saxon gneisses and granulites, and Mr.
Barrow's • description of intrusive gneiss-dykes in Forfar, suggested
the possibility that the intrusive nature of the gneiss might not be
exceptional. Moreover, M. Michel-Levy's 7 demonstration that the
protogine gneiss which forms the nucleus of Mont Blanc is an
eruptive granite, and not a basal gneiss, showed that the same
relation holds in at least one place in the Alps. There are, how-
ever, considerable differences between the protogine gneiss of Mont
Blanc and the fresh gneisses of the Cottians, and as these mountain-
groups l>elong to different Alpine zones, which are arranged on very
different plans, I was not inclined hastily to apply conclusions from
one to the other.
Impressed by these doubts, I was led to devota most of the time
at my disposal for field-work during the summer of 185)2 to a care-
ful examination of the Oottian gneisses, in the hope that by working
along the junctions some sections might be found that would settle
the exact relations of the two series. At the same time it became
necessary to settle the nature of the relation bet ween the schists and
1 Gastaldi, liera. descriz. Cart* geol. Italia, rol. i. (1871) pi. vi.
* Gastaldi, in letter to T. S. Hunt. Geol. Mag. 1887. p. 536.
3 A. C. Lawson, ' Report on the Geology of the Rainy Luke Region,' Ann.
Rep. Geol. Surv. Canada for 1887, pt. F. 182 pp and map.
* J. Lehm inn, ' Die Entstehung der altkrystaliinisohen Schiefergesteine, mit
besonderer Bezugnahnie auf das sachsiscbe Granulitgebirge. . . .,' Bonn, 2 vols.,
1884.
5 K. Danzig, ' Ueber die eruptive Natur gewisser One i see sovrie dee Granulits
im sacheischen Mittelgebirge," MitUi. Min. Instit. Univ. Kiel, vol. i. (1888)
pp. 33-79.
* G. Barrow, ' On certain [Highland] Gneisses.' Geol. Mng. 1892, pp. 64-415 ;
[«e alto Quart. Journ. Geol. Soc. vol. xlix. (1893) pp. 330-356.]
7 Michel-Ltivy, • £tude sur lea roches eriatal linen et c-ruptives det« environs du
Mont-Blanc,' Bull. Serv. Carte geol. France, no. ix. 1890, 26 pp. and plates,
r2
DR. J. W. GREGORY OX THE WALDKSSIAJ? [May 1894,
sediments of Gastaldi's * piotro verdi ' group. This subject will be
dealt with in a subsequent communication by Mr. A. M. Da vies, of the
Royal College of Science, London, and myself. Mr. Davies gave me
the great benefit of his assistance, as well as the pleasure of his
company, during the examination of the gneiss. I must moreover
express my thanks to Prof. Sacco for the opportunity of examining
the rock-collections named by Sismonda at Turin ; also to Dr. G. Gia-
notti, who guided us over the sections described by him on the south
side of the Valle Grande at Chialamberto ; to Signor Ing. Soramariva,
to whom we are indebted for much information regarding, and the
opportunity of a visit to, the Vonzo mines ; and to Prof. Stevens, of
Turin, whose kind help added much to the pleasure of a visit to the
Yalle Grande.
II. The Cottian Sequence and Previous Literature thereon.
Even before Fournet's 4 Memoire sur la Geologic de la partie des
Alpes comprise entro le Valais et l'Oisans ' 1 and Lory's monograph,
* Description goologique du Dauphine,'2 had given a comprehensive
view of the main features of the structure of the Cottians, it had
acquired a somewhat extensive literature, dating from the works of
Faujas St. Fond (1781), Robilant (17S6), Morozzo (1793), and
de Saussure (1796). "We owe to M. Kilian 3 a bibliography of the
French side of the range, and to Prof. Baretti and Dr. Portis * a
similar work for the Italian ; they are brought up to 1891 and 18S1
respectively. It is, however, here unnecessary to refer to the earlier
literature as, with the exception of the absolute age of some of the
schists and sediments, there has been a general agreement amongst
recent writers as to the relative age of the whole series. Lory, it
is true, regarded tho * schistes lustres ' of Ccsana as Triassic, a view
recently put forward again on palajontological grounds, but he fully
accepted them as younger than the underlying schists and both as
newer than tho gn%iss.
The question of the relations of the gneisses and the schists has
been twice discussed in recent years, and it is only necessary to refer
to those two memoirs. In 1887 Zaccagna published his well-known
paper 4 Sulla Geologia delle Alpi occidental^' 5 in which he described
in detail live sections across the Western Alps from Mont Blanc to
east of the Col di Tenda. He recognized the following sequence : —
1 Fonrnet, Ann. Soc. roy. Agric. Lyon, uer. 1, vol. iv. (1841) pp. 105-183,
483-500; vol. ix. (1846) pp. 1 112; Ber. 2, vol. i. (1849) pp. 185-269. pi. i.
a Lory, Bull. Soc. Stat. here, «r. 2. vol. v. (18(H) pp. 1-240, pi. i.; eer. 2,
vol. vi. (1861) pp. 1-260. pU. ii., iii. ; aer. 2, vol. vii. (1864) pp. 4-252, map.
3 Kilian, " Notes bibliogrnphiques pour aervir a l'histoire gtologiquo des
Alpes franchises- Le Daupbine," noa. 1500-1560, An 26-27, 18U0-91.
* 4 Bibliographic goologique et paleontologique d«j 1'Italie/ 2&n« Congres
Geol. Internat. Bologna, 1881, pp. 3-36.
• Zaccagna, Boll. B. Com. geoL Italia, vol. xviii. (1887) pp. 346-417,
pla. ix.-xi.
Vol. 50.] GNEISSES IN THE COTTIAN SEQUENCE. 237
Eoceue.
Cretaceous.
Jurassic.
Triassic. Grey, schistose, compact, and brecciated limestones, talc-schists with
serpentines, etc.
Permian.
Carboniferous.
Pre-Paheozoio. Zone of mica- 1. Calc-schists, mica-schists, quartzites,
schists, etc. with saccharoidal limestones, tabular
gneiss with syenites and granites.
2. Do. with serpentinous rocks, gabbros,
diabase, and amphibolic, epidotic,
and chloritic rocks.
3. Do. witli massive diabase and por-
phyry.
Zone of Central Gneiss, augengneits with white granite,
Gneiss. talcoee and micaceous granites (pro-
togine of Mont Blanc).
With the Cainozoic and Mesozoic beds we have little to do ; the
important points are : — ( 1 ) that Zaccagna agrees with Gastaldi and
some earlier writers that the whole of the true schists and the more
normal sediments associated with them must be assigned to the pre-
Palaeozoic ; (2) that he maintains that a definite sequence in them
can always be established, and that the beds of * central gneiss,'
which Gastaldi and Barctti regarded aa accidentally distributed
through the schists, occupy a constant position at the base of the
series. In his map he represents the 1 central gneiss ' as forming a
continuous band from Bussoleno to Venasca, and in bis section
across the Southern Cottians shows it as occupying the axis of a great
anticlinal. In his summary of conclusions he is very emphatic that
14 the central gneisses are not a mere lithological accident in the
mass of mica-schists and other crystalline rocks, but they hold
a constant place in the series and form the base and the nucleus of
the various ellipsoids of elevation." Further, he maintains (pp. 415,
416) that "there does not exist a gradual passage between the crys-
talline rocks of the Alps and those of the fossiliferous series, as we
ought to admit if we adopt the opinion of Lory, according to whom
the Arcbasan calc-schists of the Cottian Alps and of the valley of the
Arc represent a great part of the Triassic series."
In complete accord with the views of Zaccagna upon these main
points are those of Prof. Bonney, who in 1889 1 published his * Notes
on Two Traverses of the Crystalline Rocks of the Alps.' Bonney's
two most important conclusions were the fundamental unity of
the sequence of gneisses and schists in the Eastern and the Western
Alps and their Archa?an age. He crossed the Cottians to the north
of Zaccagna's main section and concludes " that, broadly speaking, a
stratigraphical succession can be detected in the gneisses and schists
of the Alps, and that these rocks are of Archaean age." He strongly
opposed Lory's view of the Triassic age of the 4 scbistes lustres,' or
calc-schists of Cesana, and attributed them to his Upper Archaean
1 Quart. Journ. Geol. Soc. vol. xIt. pp. 67-109.
Digitized by Google
Fig. 1. — Sketch-map illustrating the distribution of the
Wahlensian Gneisses.
[For « Oriaolo ' read 1 Criaaolo * ; for * Mere inn tiara ' read ' Mom'antaira ' ;
for * Giordano ' read * Giordani.']
Digitized by Google
Vol. 50.]
THE WALDENSIAN ON KISSES. '
series. In regard to the gneiss, however, Prof. Bonney twice sug-
gested,1 from microscopical examination, that it is 44 not impossibly
of igneous origin ; " but he insisted on the remarkable coincidence
between it and the Laurentian gneisses.'
Dr. Diener, in the admirablo summary of the subject in his • Ge-
birgsbau der Westalpon,' accepts (pp. 15, 16) the same threefold
sequence ; but he remarks (p. 33) that the evidence for Zaccogna'a
anticlinal is not conclusive, and shows that part of tho 4 schistes
lustres,' though in another district, are certainly Triassic.3
The work of both Zaccagna and Bonney was executed on the
passes ; failure, however, on previous occasions to obt-ain sufficiently
satisfactory exposures on the closelv cultivated, moraiue-strewn
flanks of the valley*, led me to trust mainly to tho peaks and
ridges and to follow the strike from north to south, in the hope of
thus finding a series of clear exposures of the junctions.
III. The Gneisses.
Zaccagna, in tho exquisite map attached to his momoir * Sulla
Geologia delle Alpi occidental^' figures the gneiss as a continuous
band from Bussoleno to Venasca, a distance of some 8l> kilometres or
50 miles. I had, therefore, planned to start at the north end, work
stea'Kly south along the western margin of the gneiss, and return
north along the eastern margin. The first day's work, however,
showed that no such siraplo scheme as this was practicable. Tho
gneiss may be found a short distance south of Bussoleno, forming a
low bank, ranging along the base of the hills, below the villages of
Fornielli and Combo ; but on attempting to work south along the
line of junction marked by Zaccagna, oue soon left the gneiss and
struck a wide stretch of mica-schists, with oalc-schists on the north-
western border. At two or three places to the south there are sm<ill
exposures of dykes or banks of the gneiss, but we could find no
trace of the great sheet of gneiss which Zaccagna's map had led
us* to expect. All along the line, the results were much the same ;
instead of the continuous band of gneiss, there appears to be really
a series of disconnected masses. This is the case not only in the
Bussoleno district, but as far south as the line of gneisses was
followed ; it is shown in the map of Vasseur and Carez, which in
this respect appears to be more accurate than Zaccagna and Mat-
tirolo's map. It seems, therefore, best to discontinue the use of
the term 4 central gneiss,* which has been applied in the area to
many different rocks and moreover assumes the point in dispute.
But as the gneisses are mainly exposed in the Waldensian valleys
they may be appropriately called the 4 Waldensian gneisses/ They
may be divided into seven groups, each of which is perhaps best
described separately : —
1 Quart. Journ. Geol. Soc. vol. xlv. (1889) pp. 83 and 99.
1 lhid. p. 97.
1 Such is the rose around Lago Paroird and Mont Brise, • Gt'birgsbau der
WesUlpen/ p. 103.
Digitized by Google
240
DB. J. W. GREQORT ON THE WALDBNSIAK [May 1894,
1. Bussoleno-Susa. (Dora Valley.)
2. Pale. (Sangonetto Valley.)
3. Meano. (Chisone Valley.)
4. Angrogna Valley.
5. Pellico Valley.
6. Barge. (Giandolo Valley.)
7. Crissolo. (Po Valley.)
Before, however, considering these, a digression to the exposure
of gneiss nearest the northern end of the Cottians may well be
msde, in order to compare the rocks of the little- known Waldensian
valleys with those of the classical massif of the Paradiso.
(a) The Paradiso Massif.
The Gran Paradiso has long been taken by geologist* as the
typo of an Alpiue massif in its simplest form, while it has been
rendered classic by the descriptions of l)esor, Gastaldi, and especially
by the well-known monograph of Baretti.1 The Paradiso belongs to
the Graian Alps, but it is a member of the same Alpine zone as the
Waldensian gneisses. It occurs immediately at the northern end of
the Cottians, and consists of a series of gneisses and schists which,
i'ig. 2. — Introduction of part of Gastaldi s mop of the Paradiso,
I I Tt'-rttti i ru t,tllt hi suftnert.
li™J Srr+riifnto, eii/rt,,fr. etc
L23 G ifta antic'ti • >. infrrisri
on the ground of lithological resemblance, have been correlated by
Gastaldi and Baretti with the similar rocks farther south. The
geology of the district has been fully described by Baretti, whilst in
1 'Studii geologici mil gnippo del Gran Pnradiao,' Atti R. Accad. Lincei,
ser. 3, Mem. toI. 1. pt i. (1877) pp. 196^313, pL. i.-tii.
Digitized by Google
Vol. 50.]
(3NEIS8K8 l!t THE C0TTIA5 SEQUENCE.
241
1892 Dr. Gianotti1 and Prof. Cheluasi * have added considerably
to our knowledge of the south-eastern corner of the massif. From
the works of these authors we know that the main part of the massif
consists of a coarse augen-gneiss which passes into a granite at the
centre and becomes finer grained around the margin ; it is surrounded
by schists, which are often intensely contorted and penetrated by
a series of gabbros and 1 pietre verdi.' Near the gneiss the strike
both of the schists and greenstones is as a rule parallel to the margin ;
and the maps show the beds of * pietre verdi ' and limestone in the
schists encircling the gneiss, in a manner which suppests that their
strike is due to uplift around a central intrusion. Gastaldi admits
that the ellipsoid of elevation of the Paradiso is due to the intrusion
of the gneiss, but he maintains that this was in a solid state, * and
this is apparently accepted by most Italian geologists. Gastaldi,
however, in the map previously quoted, of which part is here
reproduced (see fig. 2), has shown one band of the ' pietre verdi ' com-
pletely broken across by the gneiss in a manner that appears almost
inexplicable for a solid intrusion. Though not inclined to place
much reliance on Gastaldi's mapping, I thought it advisable to select
this area for the examination of the relations of the gneisses and
schists. A further advantage offered by this part of the massif
was that the line of junction of the two had recently been precisely
marked on a map to the scale of 1 : 25,000, issued by Dr. Gianotti
in illustration of his paper on the mode of formation of the valleys
around Chialamberto.
The central gneiss has been so well described macroscopically by
Baretti 4 and microscopically by Chelussi ' that there is no need
here to say more than that around the margin it is typically a
coarse augen-gneiss with felspar 4 eyes ' often 2 inches in diameter,
and with all the minerals remarkably fresh.
In the centre of the massif the gneiss, as we are told by Baretti •
and Gianotti,7 passes into a normal coarse-grained granite, without
any trace of foliation. At the actual contact with the surrounding
schists the gneiss becomes much more finely foliated and the large
felspar * eyes ' disappear. The junction, however, is unfortunately
generally covered by moraine, and actual contact is rarely to be seen.
Above the level upland valley, on the lower edge of which stands
the hamlet of Vonzo, the stream of the same name runs for some
distance along the line marked on Dr. Gianotti's map as the junction
1 G. Gianotti, 'Appunti geologic! sulla Valle di Chialamberto' (Valle di
Lanzo— Alpi Graie), Boll. Sue. geol. Ital. toI. x. (1801) pp. 149-167.
3 I. CheluHi, • Studio microscopico di alcune roccie del la Valle di Chialam-
berto in Piemonte,' pt. i. Giorn. Min. Crist, e Petrogr. vol. ii. (1891) pp. 198-
.210; -pt ii. UntL pp. 270-277.
1 Gtaataldi, Mem. descrir. Carta geol. Italia, vol. ii. (1874) p. 08.
* Baretti, * Gran Paradif 0/ Atti R, Aerad. Lincei, ser. 3, Mem. toL i. pt i.
(1877) pp. 208-211.
* Cbeluati, op. gupra cit. pt ii. Gioro. Min. Crist, e Petrogr. toI. H.
pp. 270, 271.
* Baretti, loc. snpra cit. 7 Gianotti, op. mipra cit. p. 153.
242 DB. J. W. GREGORY ON THE WALDESSIAN C^a>" l894'
of the two series ; no exposure of this can be hero seen in*itv< hut
some of the boulders on the banks and in the bed of the stream
show the actual junction.
Fig. 3 shows one of these eases : the boulder consists ot a ma »
of fine-grained gneiss including two masses of the *JP^™^33S*
series ; the foliation of the gneiss flows round the inclusion, w nic^
shows dear contact-alteration to a depth varying between 4.anaJJ
inch. The gneiss is finer in grain than any we could find there tn «i,
but other boulders showed a passage from gneiss having characters
identical with this to the normal coarse -grained rock. Microscop
examination completely demonstrates that the gneiss belong to trie
central mass. Half an inch from the contact the gneiss is clear
and colourless, and all the minerals are remarkably fresh ; the main
mass of the rock is formed by a water-clear quartz- felspar mosaic,
Fig. $.—Indu*ion qf'pUtn verdi ' hi the fjneis* of th< Vonzo Vatte'f.
[Rvproduwd from i» photograph.]
the constituents of which are often united in peguiatitic inter-
growtha. The quarts has a well-marked circular polarization ; the
orthoclasc is occasionally idiomorphie, and Carlsbad twins occur;
these crystals also show signs of MHTOtiOD. Oligoelaafl occurs only as
a few rounded grains. The mica is white and occurs in long blade-
like crystals, most of which lie along the planes of foliation; a
few, however, are scattered irregularly through the quartz- felspar
mosaic.
Vol. 50.]
ON KISSES IX THR COTTIAN 8RQURNCF.
24 :\
Adding the letter 6 to indicate foliation, and the bracket — to
show simultaneous crystallization, the formula for this rock, ac-
cording to M. Michel-Levy's system,' would be :
The rock is therefore a muscovite-granitoid gneiss.
Near the actual junction of the two rocks occur many flakes of
chlorite which have doubtless been formed by the alteration of
fragments of the 4 pietre verdi ' ; a few corroded and broken
garnets, showing optical anomalies due to strain, also occur. The
contact-line is irregular, the gneiss having cut into the included
block ; this is now so altered that it is not easy to say what was
its original constitution. The principal constituents are rounded
grains of plagioclase, small, strongly dichroic crystals of green
hornblende, and some irregular grains of glaucophane ; these are
scattered through a mass composed of rounded grains of epidote.
A little zoisite and some patches of titauoferrite are also present.
The green included fragment is, therefore, an altered basic
igneous rock and may be called a glaucophane-epidiorite.
Farther up the valley of the Vonzo the gneiss leaves the
river and runs due north, below the chalets of Oulet and west of
the crag below the Capella della Madonna di Ciavinis. No section
showing the junction could be found, but close to it the ' pictre-
vcrdi ' series is very contorted and along it loose blocks of garneti-
ferous nmphibolite and glaucophane-schist are very abundant ; these
both probably indicate contact-alteration.
The junction of the two series is, however, much better shown
on the south side of the Stura Valley, along a line to which we
were guided by Dr. Gianotti ; the sections occur on both sides
of the steep Vallone Vorso, north of the hamlet of Ortiero. In
descending the valley for some distance below the main bridle-path
one crosses the ordinary * pietre verdi ' series ; the rocks of this series
then become much contorted and garnetiferous, and 40 feet lower
down pass into a crushed decomposed rock crowded with large
garnets ; immediately below this is a fine-grained gneiss-rock which
Dr. Gianotti called a ' taloose gneiss * and accepts as the transition-
rock between the gneiss and the schists. The taloose gneiss passes
gradually below into the normal augen- gneiss. The actual junction
here is clear, but it is not easy to be sure of its exact nature, as
there has been a certain amount of slipping and squeezing out of
the soft decomposed garnet-rock.
1 'Structures et Classification des Roches eruptives,' Paris, 1889, pp. 29-30,
37-38.
I* = granitoid. F5 = apatite. a, = orthoclase.
a = granitic. Fa = zircon. q =t quartz.
7 = pegmatoid. m » white mica. A- = kyanite.
e = epidote.
The brackets are used for extraneous materials caught up by a rock during
its intrusion.
244 DR. J. W. GREGORY OX THE WALDEXSIAX [May 1 894,
The talcose gneiss macroscopicallv resembles that in contact with
the epidiorite in the Vonzo Yallev, and subsequently described from
Mustione and elsewhere in the Eastern Cottians. It appears to be
a gneiss which has absorbed much basic matter from the schists ;
while the met that the garnet-rock above it is crushed and decom-
posed is also a result of the contact-metamorphism.
On the opposite side of the Vallone Verso similar amphibohte-
schists can be seen, on the edge of the platform on which stand the
hamlets of Casa Girot and Casa Ortiero. Below them occurs a bed
of quartzite which strikes towards the gneiss. The latter is well
shown in a few small quarries ; the uppermost of these is imme-
diately below the quartzite, here altered to a quartz-schist. Ihe
gneiss" is fine-grained, and in this condition it can be traced up to
within 5 metres of the quartzite. In a second quarry, a little
below the first, the gneiss is coarser and typically augen, characters
which become more prominent as it is followed farther down the
hillside.
The schists and the quartzite here dip 23° south-east with
a strike of 3:2° south of west (magn.), whereas in the lower quarry
and in numerous exposures farther down the cliff the foliation of
the gneiss has a strike of Uf south of west (magn.). The gneiss
below the quartz-schists contains none of the 4 talcose 1 (or chloritic)
material which occurs in it when in contact with the 4 pietre verdi.
The general conclusion to be drawn from these facts seems to be
that the gneiss is here intrusive, as shown by the contact-meta-
morphism in the 4 pietre-verdi ' series, and the alteration of quartzites
into quartz-schists : and also by the transgressive junctiou of the
gneiss from its contact with the * pietre verdi 1 to the quartzite.
The actual junction could not be clearly traced, as the hill-slope
is here covered with brushwood, but in the absence of any evidence
of a fault the strikes certainly favour an intrusive junction. On
the north side of Chialamberto I had hoped for clearer evidence of
this nature ; but I failed to find the 4 terreni cristallini superiori 1
that Gastaldi figures on either side of the band of 4 serpentino,
eufotide, ecc* which his map shows in contact with the gneiss on
the north-east of Chialamberto. Nevertheless, there is some evi-
dence of a transgressive junction along the course of the stream at
the base of Monte Bellavarda, opposite Madonna di Ciavinis. The
foliation, as measured by Mr. Davies. runs 13: north of west, and
along a line at an angle of about 7oc with this (i. <. &2° south of west)
a definite succession of the beds can be recognized ; this includes
ordinary amphibolite-sehists, amphibolite with felspar- grains and
lu^ules, and talcose amphibolite-schist. In this series, moreover,
occur some masses of altered serpentine, the field-relations of which
resemble that common to the peridotites of the Cottians. The rock
consists of fairly large crystals of brown bastite, with very well-
marked schilleriiation ; the outlines are irregular and surrounded
by an altered structureless rone, which still maintains its optical
continuity with the central nucleus. These crystals are enclosed in
a light-green serpentmous mass, crowded with needles and radial
ioogle
Vol. 50.]
GNEISSES IN THE COTTIAW SEQUENCE,
245
clumps of tremolite. A few grains of olivine still remain. The rock
was therefore originally a saxonite, though the rhombic pyroxene was
probably hypersthene rather than enstatite. The mass occurs
intruded in some chlorite -schists belonging to the 4 pietre-verdi '
series ; its sudden western termination may be due either to its
having been cut off by the gneiss or to the original peridotic segre-
gation not having extended far in that direction.
We were glad to find that Signor Ing. Sommariva, of the Vonzo
mine, had arrived at the same conclusions — as to the intrusive nature
of the gneiss — as we had ; the mine lies near the contact of the two
rocks in a synclinal, whioh he believed to have boen formed at the
time of the gneissic intrusion.
(b) The Waldensian Gneisses.
1 . Bussohno — Susa. — The town of Bussoleno is situated on both
banks of the Dora Kiparia in the midst of a wide tract of moraine
and alluvium, which here separates the Grand* Uja and Punta
Lunel continuation of the Northern Cottians from the northern
end of the eastern range. The mountains on both sides of the
▼alley are mainly formed of mica-schists : but an extension of the
calc-mica-schists of Cesana runs along the base of the south side
of the valley as far east as the gorge of the Giordani, south-west of
Bussoleno. From this point a low bank of gneiss forms the foot of
the hill-slopes for some distance towards the east, and is extensively
quarried below the villages of Combe, Fornielli, and Meitre. A
similar rock, no doubt an extension of the same mass, occupies a
corresponding position on the north side of the valley extending
from Foresto di Susa to Grange. These are the northern exposures
of the Waldensian gneiss, and Zaccagna has figured them as
spreading over a wide extent of ground south and south-east of
Bussoleno,1 and thence extendiug in one unbroken line as far south
as Venasca. It was therefore natural to strike from Bussoleno
towards the south-west, to the line marked by Zaccagna as the
junction of the gneiss and the schists.
One soon found, however, that it was not possible to apply that
geologist s map too literally, and that a large extent of his 4 central
gneiss' is really occupied by mica-schists, ealc-sehists, and even
* pietre verdi.' Thus the foot of the hill-slopes at Capella Santa
ParnelLi, about 1 kilometre south-west of Bussoleno, is formed
of calc-mica-schists, in places garnetiferous ; the foliation of the
schists here dips 45° to the north-east, and strikes north-west
and south-east. Higher up the slopes the calc-schist is succeeded
1 There it a slight discrepancy here between the lettering and colouring of
Z.icc'igna's map. According to the former, the gneiss extends as far west as
Chiomonte, and it forms the whole of the basins of the Giordani and of the
lower part of the Scaglione; the colouring, howerer, marks the western ter-
mination of the gneiss about 1 kilometre to the east side of the Scaglione, the
couree of which is thus wholly on the schists; the colouring is no doubt the
more correct. ■
Digitized by Google
246 DR. J. W. GREGORY 05 THE WALDE58IAX [May 1 894,
by a great thickness of brownish mica-schist*, which can be seen
in numerous crag* around Combe, Fornielli, Tignaj, and Meitre ;
thence they c in be followed along the hills southward to Giordani,
and up the Gerrardo Valley. We found them from Giordani all
aloug the line of a traverse across country past Pinetti, Cervelli,
Conde, Travers a Mont, and Pois to Mustione.
Fig. 4. — Shetch-mitp showing the distrtbut'um of the Wahlensian
Gtteisu* in the Butsoleito district.
BM Cs+ Sekvi
ML ttwm SdkxM.
The * central gnei^a/ on the other hand, appears to have a very
restricted distribution, being limited to the bank stretching from
below Fornielli past San Basilio to below Meitre. The foliation of
the imeiss here strikes about due cast-and-west. with a dip of
75° north. A second bed occurs intercalated in the schists east
of (iiordani : it can be seen on the right bank of a stream just
above the village. Better exposures are seen as a line of low crags,
above the road from Giordani to Fornielli : at the foot of this the
path turns to Tignaj. which leaves the main road just north of
Giordani.
One kilometre south of this another gneiss-bed crops out on the
right bank «>f the Gerrardo Valley, opposite where R. is marked on
the map. It ocean here as a bed. some 35 feet wide, which appears
to be a dyke ; the junction with the surrounding gneissoid mica-
schist is irregular : the only evidence of con tact- mctamorph ism
which we noticed is that the adjoining gneiss is garnctiferous.
These three gneisses appear so strikingly similar in their litho-
locical characters that in all probability they are part of the same
1 rock.
Digitized by Google
Vol. 50.]
ONKI8SB8 IN THE COTTIAN SEQUENCE.
247
The gneiss at the quarries below Meitre, when examined micro-
scopically, is seen to consist in the main of a water-clear quartz-
felspar mosaic, which forms large white ' eyes/ around which curve
lines of long blade-like crystals of white mica. The quartz shows
well-marked undulatorv extinction ; it is often pcgmatitically asso-
ciated with the felspar. Apatite and zircons both occur in the
mosaic. The felspar is sometimes idiomorphic, and crystals of it
are seen completely enclosed in quartz.
The formula for the rock is therefore :
r<T>ay F, ffl al m a,?,
and the rock is a muscovite-gneiss.
The dyke in the (ierrardo Valloy agrees with this in the main.
The principal differences arc the small proportion of orthorlaso,
many of the crystals of which show a z >nal regrowth. Moreover
the micas are in thicker crystals, and there are a good many eroded
crystals of kyanitc ; a few grains of the last-named mineral occur in
the Bussoleno gneiss.
The formula is therefore :
T*ay F4 m«,<7,
and the rock may be regarded as an aplite.
We were unfortunate in not finding in this district any very clear
sections showing the junction of the main mass of the gneiss and
the schists ; but around Fornielli there appears to he a gradual
passage from the normal gueiss to one rendered coarsely * augen * by
numerous inclusions of quartz-nodules. At the upper end of Fornielli,
in a chestnut grove on the south side of the main road, there is
an exposure of white gneiss with similar quartz-nodules and impreg-
nated with calcareous matter. Close to this the mica-schists are
seen in situ ; they are crowded with garnets near the junction,
while the adjoining schists are strongly contorted.
Though it is not possible to prove the actual connexion of the
three gneisses, it seems highly probable that they are part of the
same massif; tho section on the following page (fig. 5) shows their
field-relations upon this view. The three rocks agree very closely
in composition, as is shown by their formulic, and in the freshness of
their minerals in contrast to those of the rotten, decomposed rocks
in which they aru intercalated ; the only differences between them
are just those which might be expected between an intruded mass
and its apophyses. In this case the Susa and Fornielli oxjiosures
represent the massif exposed by the erosion of the Dora Valley.
2. PaU. — Between the gneiss-dyke in the Gerrardo Valley and the
next exposure seen at the Col de Vcnto, the roeks along tho lino
traversed were wholly of the gneissoid mica-schist ; these occur
along a lino from Pinetti, Cervelli, Conde, Travers a Mont, Pois,
round the flanks of Punta Rossa and south along the ltio di Gravis
to Mustione and the Col de Vento. South and west of this line
Digitized by Google
Vol. 50.] WAI.DENSIAN GNEISSES IN TRK CoTTlAN 8EQ0ENCE. 249
there appears to be a great extension of the upper schists with
4 pietre verdi,' with gabbros, serpentine, amphibolites, and vario-
lites. The true Col de Vento is on the mica -schists, but imme-
diately south of it is a dyke of gneiss intrusive into the 1 pietre
verdi ? series j a narrow and not very easy gully leads to a small
col which crosses the ridge at a height of 221)0 metres. This
runs along the junction, the gneiss forming the north wall and the
serpentine the south. The serpentine 1 is greatly schist itied and
contorted, while the gneiss has a somewhat greenish eolour, doubt-
less due to the absorption of the neighbouring material. At the
upper end the gully forks, and in the northern branch the gneiss can
be seen in contact with a much altered limestone belonging to the
schist series. The gneiss between the two branches of the gully is
much decomposed. Close by the summit of the right-hand branch
tbe gneiss crosses the gully and forms the south wall, and the rock
is there still fresh.
Between the top of this gully and the Col de Vento is a band of
limestone which is cut into by the gneiss, and the junction is well
shown on the south wall of the northern fork of the gully. The
Fig. b\ — Junction of gneiss and limestone in a gully north of
Col de Vento.
accompanying figure shows the actual junction and tbe way in
which tho limestone-bedding ends off ugainst the intrusive gneiss.
The limestone is altered at tho contact : the microscope shows it to
consist of a clear twinned calcite, some small rounded masses of
untwinned calcite, and numerous small crystals of dolomite. These
are all included in what appears to be a crushed calcareous ground-
mass ; in this somo authigenous blade-like crystals of white mica
are further evidence of alteration.
In connexion with the Col de Vento gneiss-dyke it is necessary to
consider a boulder which occurs beside the path a little below
Mustione, of which a sketch is reproduced in fig. 7, p. 250. This
shows two fragments of the 1 pietre verdi ' series included in gneiss ;
both inclusions arc distinctly altered on the margin, the larger to a
depth of 1 inch, and the smaller to i inch. The gneiss belongs to the
1 '8erpentine' is hero used as a general term for any altered peridot ite.
This rock was probably a lherzolite, ns the microscope shows the presence
of both rhombic and monocliuic pyroxenes, and of a little oligoclase; these are
included in a light-green serpentine ground mawi containing many needles and
prisms of tremolite ; some of the latter are sufficiently large to show the horn-
blende cleavages.
Q.J.G.S. No. 198.
Digitized by Goog
250
DB. J, W. GREGORY ON THK WALDEN8IAN [May 1 894,
type of talcose gneisses, and is of a faint green colour ; this no doubt
it has acquired from the absorption of some of the * pietre verdi.'
The microscope shows it to consist of the usual pegmatitic quartz-
felspar mosaic with bands of white mica ; the dark colour of hand-
specimens is seen to be due to inclusions of an indeterminate
opaque material, which appears reddish-brown by reflected light.
A series of broken and corroded garnets, often showing double
refraction, also represents material collected from the surrounding
schists. The foliation of the gneiss flows round the included frag-
ments, like a true fluxion-structure. Though we did nof find
similar inclusions in situ at the Col, the exact resemblance of the
gneisses leaves little doubt that it was derived from the dyke which
we examined, or from a similar one.
Fig. 7. — Gneiss, with included fragments of the • pietre verdi1
aeries at Mustione.
South of the gneiss, along the northern arete of Punta Costa-
bruna, the serpentinous schists (probably an altered lherzolite) rise
into a sharp crag ; south of this, the mica-schists recur again, and
these form the summit. On the eastern side of the pass and ridge a
long gradual slope of meadow-land extends down to the Songonetto
Valley, and consequently there are no exposures. The gneiss, how-
ever, occurs extensively developed on both sides of this valley ; on
the north it forms the ridge of Monte Salancia, from the crags of the
Kocca del Moutone to Monto Luzera (the Punta Siudre of the 1
map). On the south side it forms the northern arete of Rocca Rosso,
see fig. 8, p. 2.51. The gneisses of tho two sides of the valley arc at
first separated by the schists, a wedge of which appears to extend
into the gneiss, as far as tho 1500-metre contour, down the Poirent
Valley (a tributary of the Sangonetto). East of this point, as far as
Dirotto, all the exposures seen were of gneiss. Still farther down
the valley widens, and, as we had no time to leave the road, we could
see no rocks in situ.
Digitized by Google
Vol. 50. J
ON KISS KS IN THE COTTIAN SEQUENCE.
2.51
Unfortunately lack of time prevented any attempt at a precise
determination of the boundaries of the gneiss, even if such be pos-
sible; but it seems most probable that the dyke at the upper
Col de Vento is an offshoot from the great mass of gneiss about
Pale.
Fig. 8. — Sketch-map of the gneiss exposures round Col de Vento,
[For 1 Sangoretto ' read ' Sangonetto.']
.3. Meano, Perosa, and Chisone Valley. — On Zaccagna's map the
gneiss band is shown to cross the Chisone Valley between Moano
and Roure; two unnamed streams are marked as traversing the
gneiss, and these occupy the positions of the Borsetto on the south
side of the Chisone and the Balma on the north. Meano is itself
placed as on the extreme eastern margin of a granite which here
separates the schists and the gneiss. Eastward from Meano to
Pinerolo the whole valley of the Chisone is coloured as schist. There
are, however, at S. Germano, large quaTries of a pale coarse gneiss,
which seems to be a typical 1 central gneiss.' But in this part of t he
valley the chances of actual junctions are very remote ; and, as
Prof. Bonney has already described the rock and remarked on its
possibly intrusive nature,1 it did not seem necessary to stop to
examine it.
After leaving Perosa Argentina the road rises gradually, and there
are no exposures worth mentioning, though the hills on either side
are clearly of mica-schist ; 1| kilometre distant, however, a quarry
in the pale-coloured gneiss occurs on the northern side of the road.
1 * Two Traverses, etc./ Quart. Journ. Geo!. Soc. vol. xlr. (1889) p. 83.
s 2
Digitized by Google
2o2
DR. J. W. GREGORY ON THE WXLDKN81AN [May 1 894,
The microscopic structure of the rock has been described by Prof.
Bonncy (op. supra cit. p. 104) ; the only addition that I would desire
to make to this is in regard to the presence of the large number
of dark segregations. These are often at least 4 inches wide and
12 to in inches long; the longest diameter of the fragments is
always parallel to the foliation.
On the opposite sido of the river the gneiss is much better seen
in some larger quarries, while on the eastern margin of the mass a
certain amount of evidence as to the junction is obtainable. The
gneiss forms an irregular bank occupying the axis of an anticlinal ;
the schists on the eaat side dip 10° W.S.W., while in the cliff
below the ruined castle of Brandonegna they dip 10° N.W. At
the foot of the cliff the gneiss is fairly coarse, but when traced
towards the junction it becomes finer, and it is not easy in the lield
to fix on the exact line of separation between the gneiss and the
gneissoid mica-schists which overlie it. The microscope, however,
leaves no doubt of the distinctions between the igneous and the
clastic rock«.
The igneous gneiss near the junction is finer-grained than that
seen in the quarry on the opposite side of the river ; it differs from
the gneisses that have been previously described from Bussoleno
and the Gerrardo Valley by the presence of a good deal of biotitc in
addition lo the white mica. Epidotc in small rounded grains is also
abundant. This and the micas are included in a groundmass of a
water-clear quartz-felspar mosaic, which was the last constituent to
solidify. The formula may thus be written :
. -\
IM>ay F.^Mnw, a,o ;
and so the rock is a typical Waldensian gneiss with some foreign
inclusions.
An examination of one of the most gneissoid of the adjoining
mica-schists shows several marked differences. The materials in
this belong to two very different sets. There are some quartz and
zoisite aggregates which doubtless represent broken-down plagio-
clase; they are included in an indeterminate granular material,
which contains many small authigenous flakes of white mica. These
represent the original constituent* of the mica-schists, now com-
pletely metamorphosed by the intrusion of the second group of con-
stituents. There are thin bands of fresh grauulite, composed of
quartz, orthoclase, and some white mica.
The formula for this rock is :
F*ay (ry .r)F8 4»Mrt, «,y.
It is probably due to the injection of the schists by gneissic
materials, similar to those cases around the protogine intrusion of
Mont Blanc which have been described by M. Michel-Levy.
The brown schists recur to the west of this narrow band of gneiss,
and before attaining Mcano a cliff is passed in which they are
Digitized by Google
Vol. 50.]
emusssa in thk coitian si.un.Mi:.
almost vertical, with an E.S.E. strike ; a well -marked band of fault -
breccia here indicates a fault. Thence westward no sections occur
on the roud until reaching La Balma, where, beside the inule-]>ath
at the went end of the village, there is a crag of the ordinary brown
gneissoid mica-schist dipping 42° to west of north. The same
*chist« extend up the Balma Valley to halfway between the conflu-
ence of the Balma and the Forcho and the talc-mine at Eloussa; then
they recur ahove the mine, where an amphibolito occurs in them :
they also form the lower slopes of the liocca Bossa, and thence they
can be followed to the south side of the Col II u--a,and southward to
the summit of Monte Boeciarda. Near the AIjk' di Bocciarda, how-
ever, banks of the central gneiss crop up from the pastures, and
appear to extend east towards the l'unta Sara>ina and the
Monte Uja. The actual junction here is hidden by pastures, and an
attempt was therefore made to descend to the south in the hope of
finding it exposed. The head of the Comba di Bocciarda is close
to the junction, and a small galena-mine may mark the exact
position ; owing to the steepness of the descent, however, and a mist
that prevented our following the junction, we saw nothing Inn
gneissoid mica- schists, with some ampbibolites, till we reached the
1900-metre contour. The Roc del I'elvo. which rises above the
stream from the base of the great cliff down which we had scrambled,
is a sharp pyramid of gneiss and affords clear evidence of intrusion.
The foliation of the gneiss dips b*i N.N.E.. while the strike
is E. 27° B. ; 20 yards from the junction with the gneiss the
schists to the north are almost horizontal, but at the contact they
are sharply bent upward and are much altered. The gneiss at the
junction is impregnated with lines and fragments of dark-coloured
iucludcd material. M irroseopic examination show s that the rock
is a normal Waldensian gm iss. It differs from that described from
Bussoleno by the presence of much extraneous matter occurring as
lines and rolled-out fragments. Most of the included material is
indeterminable, but Hakes of chlorite and some rolled, broken,
and slightly doubly-refracting garnets may be recognized. The in-
clusions farther from the contact are rarer and more altered ; they
consist in the main of green and brown hornblende and numerous
small garnets ; there are numerous idioraorphic but corroded
crystals of orthoelaso in the gneiss. The adjoining schists present
the same characters us that above the gneiss in the section south of
the Chisone ; the rocks consist of bands of chloritic and amphibolic
material separated by thin seams of granulite.
A manganese vein which has been worked occurs along t In-
junction of the gneiss and schists, on both sides of the valley. There
are no slickci isided surfaces or other evidence of a lault. and
the whole as\>cct is that of an intrusive igneous mass. This i»
clearly demonstrated by the contortion and metatnorphism of the
adjoining schists, and the inclusions in the gneiss.
In regard to the possible existence of another bed of intrusive gneiss
farther west, between Castel del Bosc and Eloure, I am unable to
express a definite opinion. Zaceagna and Mattirolo's map marks the
254
DR. J. W. GREGORY ON THE W ALD EN8IAN [May 1 894,
south-eastern limit of the gneiss as crossing the main valley at the
confluence of the Balma and the Chisone ; we went for some little
distance beyond this point, and failed to find anything but the brown
mica-schists. If the gneiss does, however, occur, it cannot be con-
tinuous with that of the Bocciarda and the Pelvo, or we should have
seen it in our traverse to the north. Abundance of the gneiss, how-
ever, occurs on a talus slope to the south-west of Castel del Bosc, by
the first fork after crossing the Chisone, along the bridle-path leading
to the hamlet of Gamer. Erratics of the same rock are found
on the grass slopes west of the summit of Punta Medio Muret,
and probably indicate its occurrence somewhere along the ridge
between this peak and Punta Raccias; but a dense cloud pre-
vented any search for the rock in situ at this point. With these
exceptions the whole of the rocks crossed between Castel del Bosc
and Perrero were of the schist series, with intrusive amphibolites
and interbedded limestones and dolomites. The last are well seen in
some crags on tho south-eastern ridge of Punta Medio Muret, between
the summit and the point marked 2004 metres ; the dolomite is
much contorted, and is associated with some mica-schists containing
enormous garnets. The actual summit of Punta Medio Muret is
made up of the gneissoid mica-schist which so often occurs in the
neighbourhood of the intrusive gneisses. Between Castel del Bosc
and Garner the schists have a prevalent east-and-west strike ; but
between Massello and Perrero tho strike has worked round to
W. 30° N.
Near Perrero occur several large beds of amphibolite, as at a crag
above Maniglia and east of Quin, which is apparently intrusive
along the strike. A similar rock, probably an epidiorite, is worked
for road-metal at a quarry £ kilometre east of Perrero. It occurs
here in a position on which Zaccagna has marked 4 central gneiss.'
There did not seem to be any evidence of the existence of that rock
at this poiut. There is a good exposure of mica-schist, richer in
mica and paler in colour than is usual, at the sharp betid of the
road about 1 kilometre from Perrero ; here a foot-bridge crosses the
Germanasca and a bridle-path leads south to Grangette and Poet
Soprano, as far as which all the exposures noted were of the coarse
gneissoid mica-schist. Above the latter, large garnets become
abundant; farther up, where the path bonds round the flank of
Bocca del Cavalupo at a part where it ruus level for some hundreds
of yards, there is an amphibolite which is clearly intrusive into the
gneissoid mica-schists. The path thence rises to the ridge between
Rocca Bianca and Bocca del Cavalupo, which it crosses by a col at
the height of about 2025 metres.
From this point we kept south along the main ridge as far as
Punta Cornour. The whole line is marked by Zaccagna as * central
gneiss/ and it is therefore advisable briefly to refer to the main
types of rocks which compose it. At the col between Rocca Bianca
and the Bocca del Cavalupo, the rock is a pure white, massive,
crystalline, saccharoidal limestone, which has been there quarried for
the kilometre-posts on the new military road. The limestone is
Digitized by Google
n
Vol.
IN THE C0TTIA5 SEQUENCE.
255
inclined to the north, and is overlain by mica-schists which form the
2051-nietro point north of the col ; the band thonce rises, and is
succeeded by masses of dolomite intensely folded and contorted and
with beds of 'pietre verdi/ probably of a clastic origin, caught in
between the limestone masses. Tho beds here strike 35° N. of \VM
while the thrust has come from approximately W. by S. Along
this ridge, in spite of the intense foldings of the rocks, there is little
evidence of any definite schistosity, and the actual summit of ltocca
Bianca (2379 metres) is of a rock with foliation so imperfect that in
the field we called it a micaceous grit ; judging, howover, from the
great extent to which the quartz-grains are seen to be corroded, when
examined undor the microscope, this rock is probably a quartz-
porphyry. »South of the Colletta Bianca the rocks become more
schistose and belong to the 1 pietre verdi ? series with numerous quartz-
The summits of Cima del Liste and Punt a Uruta, however,
a return to a less foliated series, being formed of a micaceous
grit or schist breaking into largo flat slabs, with a general strike
north and south, at one place working to lu° E. of X. : the dip is
13° west. Farther (south the strike is 10° W. of N., with a westerly
dip of 10°. Associated with these evenly-foliated schists there are,
on the south face of Punta Bruta, some interstratified thin green beds
which probably represent layers of volcanic ash. There are also
numerous blocks of a green rock in the same schists ; they range
from about \\ to 3 feet in length, and in their present form ttre
lenticular; the long axes are in the plane of foliation, the lines of
which bend round the blocks. Microscopic examination shows
them to consist of garnets, chlorite, trcmolitc, and cpidote ; they
represent altered blocks of a basic igneous rock, and their asso-
ciation with what is possibly a bed of volcanic ash led us in the
field to consider the possibility of their being ejected blocks. The
microscopic evidence neither confirms nor conclusively disproves this
hypothesis.
In many places along this ridge between the IJocca del Cavalupo
and Punta Cornour the rocks are either not foliated, or the foliation,
sach as it is, is coincident with the bedding; this is probably the
ease also with tho rock which includes the eelogite-bloeks. In tne
roches moutonnees' around I-agho d'Envoi, a charming little lake
in a glaciated rock-basin, wo have clear ovidence that such is not
ilways the case, as the vein there has been intensely contorted,
re tho foliation of the rocks ; the foliation here has the normal
of 10° W. of X., with a westerly clip of 10°. Around the Hanks
Capello d'Envoi the schists become coarser and the limestones
schistic* ed.
vidence for the same independence of the foliation and stratifi-
cation is seer* in the view of Punta Cornour from Trcdici Lag hi. A
massive bank of white roek (probably dolomite) may be observed
interstratified between masses of tho 4 pietre-verdi ' series ; tho white
rock dips to the west, but the foliation dips much more sharply and
crosses tho bedding at a high angle.
the summit of Punta Cornour, the large garnets and the
itized by
256 DR. J. W. GREOOBT OH THE WALDKHSIAN [MttJ 1894,
crushing of the schists indicate a region of greater disturbance thau
in the Cima del Liste area.
Boulders of the central augen-gueiss occur on the northern face
of the Punta Cornour, and this, combiued with other facts subse-
quently noted around Bobbio Pellice (5 kilometres south), led me to
think that this is probably an outcrop of the gneiss to the south.
Ill-health, however, prevented an examination of the ground in this
direction.
4. Angrogna Valley. — We had thus crossed from Perrero to the
highest point between the Germanasca and the Pellice valleys,
keeping along the line coloured by Zaccagna and Mattirolo as
4 central gneiss,' without seeing the slightest traces of this rock,
except for the single boulder on the Punta Cornour. Limestones,
dolomite8,grits,andsomequartz-porphyry rendered slightly schistose,
were the main rocks met with. The north-and-south traverse was
therefore discontinued, and we then descended the Angrogna Valley
towards the east in the hope of finding on its flanks some further
exposures of gneiss, which it was possible that Zaccagna might have
accidentally represented too far west.
Nevertheless, from Passo ltoussa as far east as Gaisset, the only
rocks seen were schists with interstratified beds, of which some
are apparently intrusive amphibolites and others clastic green rocks.
At Gaisset, however, a mass of fine-grained and locally foliated
gabbro crosses the valley and forms a massive hill on the north side
of that chalet ; before crossing the stream near Pra del Toruo, a
dyke of compact dark-green porphyrite crops out across the path.
Below Pra del Torno the normal mica-schists recur, and they are at
first garnetiferous. Farther from the gabbro massif the schists are
finer and less crystalline, and opposite the bridge at the angle of a
sharp bend of the river, nearly 1 kilometre S.S.W. of Pra del Torno,
the schists are comparatively unaltered and anthracitic.
A little farther round the curve a sharp cragi tiocca Roccaglie,
overhangs the path to the north, and this is cut through by dykes
of white aplite ; a much finer exposure occurs in some rocks which
here interrupt the course of the stream.
The main rock is a member of the *pietre-verdi' series; the
commonest variety is a rock which is probably an altered andesite,
cut through by a fine-grained gabbro dyke. Both rocks have
been subsequently invaded by a complex of intrusive aplite- veins (see
fig. 9, p. 257). The aplite or granulite-veins vary in width from
a few inches to 4 feet ; and the coarseness of the rock varies with
the width of the dykes. Microscopic examination shows that the
rock consists in the main of quartz-felspar mosaic, with some larger
eroded crystals of orthoclase and a foliation determined by bands of
white mica. Its formula, excluding accessory minerals and some
foreign material absorbed from the surrounding rock, is :
T*ay ma ay
which is that of the typical gneiss of the district.
Digitized by Google
Vol. 50.]
<;si:issHi in in I corn \ n MKWBMOB.
IV, 7
The evidence of this exposure is unquestionable. There can be
no doubt of the iutrusive character of the dykes, nor that these are
composed of an acid rock in which all gradations can be traced from
a compact aplite or granulite to a fairly coarse, well-foliated gneiss.
It appears that the dykes are an offshoot from a large muss below,
which has not been exposed : its existence can be interred from the
elevation of the overlying beds into an anticlinal, an is shown by the
photograph here reproduced.
East of the exposure which has just been described, along the
jwith through Angrogna to Torre I'ellice, the beds all consist of t in-
ordinary mica-schist, dipping south-east.
Fig. 9. — Veins of gneiss {aplite) in the " pietre verdi ' aeries,
Amjroyna Valley.
The aplite-teins run oMiqu»ly upward acroua the right-hand lower corner ; one
occur* juat above the lower margin and below the obliquo ncries.
5. The Vellice Valley. — According t<» Zaccagna's description and
map,1 the 4 ceutral gneiss ' crosses the Pellice V alloy near liobbio
lVllice; it occupies the area between the Rio Snbiaeoo and the Rio
Ouello, the town being on the eastern margin. At Hobbiothe main
valley is occupied by moraine, and the hill-slopes are so wooded
and cultivated that no exposures could be found ; to the west, how-
ever, a small footpath (named the Via Podio) branches from the
Villanova bridle-path and ascends through some orchards to the
1 'Sulla Geologia delle Alpi occidentali,' Boll. R. Coin. geol. Ital. vol xviii.
I*s7, P. :W4. pi m
igitized by Goog
258
DH. J. W. OREO OR T ON THR WALDRlfSIAN [May 1 894,
north. Five minutes* walk along this, in a field north of the
path, there is an exposure of a pale-coloured, foliated, fine gneiss.
The rock is worked here, and the quarry is known to the peasants as
the 1 Rocca Bianca.' The actual junction cannot be seen, but brown
mica-schists can be found at a little distance above and below it.
The foliation dips about 20° west, and is approximately the same
as that of the surrounding schists. In the Cruello Valley there
are numerous blocks of gneiss scattered about the lower part of
the stream : as this is followed to tho north, the schists become
coarser and very contorted. The valley, however, is closed by two
vertical side-walls and a waterfall, which may mark the junction
with a northern massof gneiss. Butthe path towards Mai pertus shows
only the ordinary mica-schists, and the peasants whom I asked
could not tell me of any place where the gneiss occurred, except at
Rocca Bianca ; and as they all immediately recognized the specimens
from that quarry, some value may be attached to their evidence.
All, therefore, that can be safely asserted about the gneiss here is
that it occurs as a thin sheet or dyke, which is probably only an
offshoot from a mass to the north, between Bobbio and Cima
Chiapis, though it is possible that it is not at all or but slightly
exposed on the surface.
A more extensive exposure in the Pellice Valley occurs on the
south bank east of Villar Pellico ; the rock is here a coarse augen-
gneiss, with the minerals as usual all strikingly fresh and pale. It is
worked in a number of quarries, the line of which is connected by a
series of crags which stand out above the soft schists and talus.
Being unfortunately compelled to leave the Pellice rather hastily,
we were unable to examine the field relations of this band of gneiss.
It must therefore be here also left doubtful whether the rock is
anything more than an intrusive sheet. The northern slopes of the
Pellice Valley all appear to be made up of the schist, and there is
therefore seemingly no connexion botweon the gneiss on the southern
bank of the Pellico and the outcrop in the Angrogua Valley.
6. Barge. — Gastaldi has described the occurrence of the 4 central
gneiss ' at Barge, and has inferred therefrom that it is a continuation
of the same rock seen farther west near Ostana, here brought up to
the surface by a fold. Zaccagna, however, whose Section II. crosses
the country a little north of this town, does not admit the
occurrence of the gneiss there. The rock is one of the pale-coloured,
coarse augen-gneisses, exactly similar to that which he has else-
where described as 4 central gneiss.' The foliation dips S.W., as
does also that of the mica-schists which succeed it to the west : I had
not, however, the time to search for a junction, and indeed should
hardly expect to find one that would be at all satisfactory.
After passing the 788-metre point the schists dip eastward, but
they subsequently become horizontal, and at a sharp bend in the road
at the 833-metre level the schists are black and dip south-west.
7. Critsolo. — Zaccagna's main section through tho Cottians
crosses the valley of the Po at Crissolo and thence continues east-
Digitized by Google
Vol. 50.]
GNEISSES IN THE COTTIAN 8KQDENCK.
259
ward, traversing the band of * central gneiss/ That geologist has
described the sections along this line with much care. Hence it
was natural that I should expect to discover much closer agreement
with the facts than in regions to the north, whero the linos must
have been hastily and diagrammatically sketched in. I therefore
turned to the valley of the Po in the hope of finding the gneiss
exactly where Zaccagua has placed it in his map. In this I was not
disappointed : the gneiss cud be seen in numerous roadside exposures
between the hamlet of Calcinere, west of Paesana, and the western
end of a gorge due south of Crampetti. The gneiss forms steep,
barren, craggy slopes, easily distinguishable from the softer and
more fertile schists.
The section which best shows the relations of the gneiss and the
schists occurs on the south bank of the river near a footbridge, at
the upper end of a gorge east of Crissolo. The base of the hillside
here is of coarse augen-gneiss, which is covered by the schists. The
normal schist at more than 20 feet from the gneiss is a thin-bedded
lead-coloured rock, with some in torat ratified amphibolites.
As we approach the gneiss the schists become coarser, till they
form a gneissoid mica-schist — such as is generally observed near the
contact with the Waldensian gneisses throughout the Cottimi
The lead-coloured schists contain much material that can be iden-
tified as having been originally clastic grains ; as wc approach the
gneiss this lessens iu amount and water-clear quartz-felspar mosaic
becomes the chief constituent. This is associated with numerous
garnets, and some muscovite, epidote, and chlorite ; there is also
some indeterminate material which represents the less altered part
of the original rock. Still nearer the gneiss the garnets disappear,
but some earthy grey zoi site-aggregates represent the original
constituents of the 4 pietre verdi ' ; the bulk of the rock is formed of
white mica, orthoclase, and quartz-ortboclase mosaic.
In addition to this contact-metamorphism, further proof of the
intrusive nature of the gneiss in this section is afforded by some
dykes of aplite which strike off from the gneiss ; these are best seen
where they cross some bauds of amphibolites which occur in the
schists. Owing to the groat difference in the chemical composition
of the aplite and the amphibolites, the junction between them is
much sharper than that between tho aplite and the mica-schists ;
it is very irregular, sending small projections into tho amphibolile
in a way that clearly shows the intrusive nature of the former.
Unfortunately, it was not possible to trace the aplite-dyke into the
gueiss, as the junction was hidden by moraine matter, and it was
not even possible to be absolutely certain that the amphibolites
were in situ. Their occurrence as blocks along a definite narrow
tine, however, rendered it highly probable, and any doubt was re-
moved by tho discover}' at the foot of the slope of a large boulder of
mica-schist containing a vein of amphibolite.
There is, moreover, a marked discordauce between the strike of
the gneiss and that of the schists, which, in the absence of any
evidence for a fault, affords further proof of intrusion.
200
DR. J. W. GRKOORY ON THE WALDENSIAN
[May 1894,
IV. Conclusions as to the Relations of the Beds.
Prof. Bonney has recently insisted on tho great difficulties in
the way of geological mapping in the Alps,1 and though in the
Eastern Cottians there is not much difficulty from snow or glaciers,
the great extent of the moraines and vineyards in the valleys, and of
the pastures on the higher slopes, prevents any detailed mapping of
much of the area. The ruggedness of the country, the depth of the
valleys, and the lack of accommodation add further obstacles to the
investigation by causing 60 much of the time to be necessarily spent
in walking to one's field of work.
It was impossible, in the short time available for field work, to
prepare any detailed map of the geology of the area, or even to
follow, as I had intended, the whole length of the junction of the
gneiss and the schists. This has been rendered less necessary by
the clearness of the sections at some points. A rough sketch-map
of the area is appended, on which tho main facts have been inserted
(see fig. 1, p. 238). and it is perhaps advisable here to summarize
briefly the evidence afforded by the foregoing descriptions.
As has been already remarked, according to the generally -
accepted theory, the * central gneiss * is the lowest of a three-told
series of Archaean rocks, and its position at the base of the series ia
due to its being the oldest of the three, the others having been
deposited upon it. Agaiust this view the evidence now presented
is fairly conclusive. It will be generally admittod that if this be
true, a strong unconformity must occur between the schists and the
gneiss ; in support of this, it is only necessary to refer to tho map of
Onstaldi reprinted on p. 240 and to his sections, such as that from
Koehe Melon to Lanzo a or at Monte Resta3; the section of Dr.
Gianotti 4 shows the same for the neighbourhood of Chialumhcrto.
With such an unconformity it is incredible that no fragments or
pebbles of the gneiss should occur in the schists. Tho latter are a
very extensive series of deposits, and contain several beds of con-
glomerate, such as that at Tredici Laghi and under Punta Bruta.
But in no case do fragments of the » centrul gneiss ' occur in them ;
a section of the Tredici Laghi conglomerate in the schist series shows
that the pebbles consist of a felspar-zoisitc aggregate with numerous
crystals of rutilo and some small flakes of biotite. These pebbles are
very dusty, and their outlines are rounded as if by crushing ; they
are set in a matrix of a water-clear mylonitic mosaic of quartz and
felspar, which contains long blade-like crystals running round the
inclusions. The evidence of the slide is not conclusive, but the
rock appears more probably to have been formed by the crushing of
a felspar-conglomerate than of an augen-guciss.
At not one of the sections examined was there any evidence of
1 Bonney, ' On the Crystalline Schittts and their Rotation to the Meoozoic
Rooks in the Lepontine Alps,' Quart. Journ. Geol. Soc. vol. xlvi. (1890)
pp. 187, 188.
J Ga<«taldi, 4 Studii geologici guile Alpi oocidentali,' Mem. descriz. Carta geol.
Italia, vol. ii. (1874) pi. i. f. 2.
3 Ibid. vol. i (1871) pi. v. * Gianotti. op. jam cit. pi. v.
Vol. 50.J
GNEISSES IN THE COTTIAN SEQUENCE.
the derivation of the schists from the gneiss, or of any erosion of
the surface of the latter.
In regard to the possible alternative theory of the gneiss being
faulted up through the schist, the evidence is also strong, though it
is again all negative. The absence of any slickensides or fault-rock
along the junctions, the sharpness of the junction where the gneiss
adjoins rocks of dissimilar composition and its indefinite nature at
places where the gneiss and the schists are of similar chemical
composition, and, finally, the great irregularity and complexity of
the faults and thrust-planes that would be necessary to account for the
field relations of the two, all combine to dismiss this bypothosis.
The ]>ositivc evidence, however, as to tho relations of the two
series is fairly complete. It may be divided into four groups.
1. Contact- Phenomena, (a) In the Gneiss. Zaccag^a has re-
marked on the fact that the 4 central gneiss' passes into a true
granite when at some distance from the junction,1 a fact which he
noted in the valleys of the Pellice and the Cbisono ; Baretti has
described the same in the Paradiso massif.2 Wo may, therefore, to
some extent regard the foliation as a marginal structure, such as that
which is not uncommon around unquestionably intrusive granites/
When the rock is examined close to the junction, it can be
gradually traced from a coarse to a fine gneiss. This may be seen
around the Paradiso massif, as below Casa Ortiera, at Forniclli, near
Bussoleno, on the banks of the Chisone, kilometre above Perosa,
and is especially well shown at the junction in the Po Valley below
Crissolo ; at this locality the fine gneiss passes into a compact aplite.
In other places the margin of the gneiss has incorporated sufficient of
the neighbouring schists to considerably affect its general character ;
in extreme cases the gneiss has been altered into a greenish talcoso
gneiss, as near Chialamberto and Perosa.
(b) In the Schists. The alterations here vary greatly , according to
the nature of the rocks with which the gneiss is in contact. When the
rock is a quartzito it is converted into a quartz, as at Casa Ortiera ;
amphibolites and epidiorites arc converted into glaucophane and
hornblende-schists, while the mica-schists are rendered gneissoid at
the contact and richly garnetiferous farther from the actual junction.
Silliraanite, kyanite, cordicrite, and other minerals are also developed,
while a band of an intensely altered, decomposed rock often occurs
along the actual contact-line ; this is especially well shown south
of Chialamberto and in the Po Valley opposite Ostana.
2. Included Fragments. Around the margin of the Paradiso
massif, as along the Vonzo Valley, in the gneiss of the Hoc del
1 Zaocagna, ' Sulla Geologia delle Alpi occidentali,' Boll. B. Gom. geol. Ital.
toI. xriii. (1887) p. 379, and elsewhere.
2 Baretti, ' Grau Paradiao,' Atti B. Accad. Lincei, ser. 8, Mem. vol. i. pt. i.
(1877) pp. 208. 210, 214.
3 See Boeenbusch, 4 Mikroekop. Phywogr. d. Massigen GeBteine,' 2nd ed.
(1887) toI. ii. p. 41.
202
DR. J. W. GBEGOBT ON THE WALDEKSIAN [May I 894,
Pelvo at the end of the Bocciarda Valley, at Mustione, etc., fragment*
of the amphibolites of the mica-schist series are included in the
gneiss ; the contact-alteration on the margin of the inclusions, and
the flow of the gneiss around them, prove that they are fragments of
the schists caught up by the molten rock.
3. Apophyses from the Gneiss. Opposite Ostana in the Po
Valley, near Bobbio in the Pellice Valley, and below Pra del Torno in
the Angrogna Valley, dykes of aplite, which present all the characters
of apophyses from the gneiss, break through the schists ; in the last
case quoted a complete passage can be traced from the fine-grained
aplite to a well-foliated gneiss.
4. Transgressive Junctions. Cases of these are the contact of
the gneiss at Bussoleno with the calc-schists and gneissoid mica-
schists ; of the gneiss on the south side of the Valle Grande with
the 4 pietre verdi ' series, quartzites, and mica-schists ; at tho
upper Col de Vento, where it works across from the serpentine to
the calc-schists and dolomite ; the discordance of the strike of the
second series around Crissolo, where, according to a manuscript
map prepared and kindly lent to us by Dr. Gianotti, the gneiss
transgresses from the mica- schists to the calc-schists.
5. The up-tilting of the schists at their contact with the gneiss
at the Roc del Pelvo, and the irregularity of the line of junction of
the two rocks — when specimens showing it are examined under
the microscope — are further proofs of the intrusive nature of the
Waldensian gneisses.
V. The Coxtact-Mbtamorphism.
The normal phenomena of contact>metamorphism are well shown
around the Waldensian gneisses, and the development of new minerals
has sometimes taken place on an extensive scale. Among others the
following have thus been formed: quartz, white mica, biotite, ortho-
clase, microcline, oligoclase, garnets, kyanite, epidote, zoisite, and
sphene. The extent to which this has proceeded varies enormously ;
thus the quartzites of the Valle Grande have been converted into
quartz-schists along only a very narrow band ; at the Roc del Pelvo,
in the Comba di Bocciarda, new minerals have been developed for
merely a short distance from the gneiss, while the alteration around
the dykes of the Angrogna Valley only affects the neighbouring rocks
over a breadth varying from £ to about 2 inches. In other places, as
in tho Po Valley, tho rocks have been intensely altered for 50 feet
from the margin. There is, however, nothing in this to justify the
charge of capriciousness often made against contact-metamorphism :
it may be selective metamorphism, but good reasons can be found to
explain the selection.
The variation in the extent to which this action has proceeded
around the Waldensian gneisses seems to depend on two main factors,
Vol. 50.]
GNEISSES IN THE COTTIA3T SBHUKNCE.
2b"3
— the balk of the intrusive rock and the nature of the beds with
which it has come in contact. Thus, as illustrations of the
former, we may refer to the very thin contact-zone around the
Angrogua dykes, which are apparently but tongues intrusive into
the schists, so that no continued flow of molten matter ever occurred
through them. The dyke at the upper Col do Vento is larger and
probably rose to a considerable height above tho present level of
the ridge ; a wider zone has therefore been affected. Around the
gneiss massifs the contact-metamorphism is much more strikingly
developed ; here the extent varies according to whether the gueiss
meets the schists as a vertical wall, as it does in the gorge of the
Comba, or forms a low bank upon which the schists rest, as in the
valleys of the Po and tho Dora and in the Paradiso massif on the
south side of the Valle Grande. In the latter cases the contact-
metamorphism is most strongly marked because the schists then
acted, to use the conventional illustration, as a * piecrust ' ; they were
in contact with the gneiss over a wide area, and through them the
heat given off by the consolidating rock was slowly conducted.
The second condition which determines the extent of the meta-
morphism is the nature of the rock in contact with the gneiss. Where
this is one of the amphibolites or other rock of the 'pietre verdi*
group, the junction is sharp and definite ; where the older rock is
of a comparatively simple composition, such as a quartzite, it may
be rendered more schistose, but few secondary minerals have been
developed in it. At places where the gneiss has been intruded into
a rock of a similar composition, such as mica-schist, a much greater
change has been effected ; tho mica-schists have then been rendered
gneissoid, and it is often difficult in the field to determine the exact
line of separation between the two rocks. Thus, in the sections on
the south side of the Chisone, east of Meano, wo were not at all
sure — in the field— of the exact position of the contact ; the micro-
scope, however, at once enables the two to be separated.
M. Michel-Levy has pointed out similar features in the contact-
phenomena of the gneiss of the Central Plateau of France. Thus
he shows 1 that, where the gneiss (or foliated granite) occurs in great
mass and is intruded into rocks which are also aoid in character,
they are united by a passHge-zone combining the characters of the
two rocks. When, on the other hand, the mass of intrusive rock
is comparatively small, as in a dyke, or where it cuts through rocks
of a very different chemical composition, then the contact is very
sharp.'
In concluding this section it may be remarked that the contact-
metamorphism affords additional evidence as to the conditions
under which the gneisses consolidated. Considering the massiveness
1 Michet-L^Tj, 4 Cotnpte-rendu de la Course du 19 aottt, de Senior k Saulieu,
par la Motte-Teraant,' Butt. Soc. gfel. France, eer. 3, toI. tm. (1879) pp. 852, 853.
3 Id. ' Oompte-rendu de la Course du 19 aout, d'Avallon a Chastellux,
op. eii. p. 845 ; 4 Compte-rendu . . . a Allignj, Goie, Penaier**,' ihid. p. 872
and ' Compte-rendu . . . de Seinur a Saulieu . . ., ibid. pp. 853, 854.
2G4
DR. J. W. GREGORY ON THE WALDEN8IAN [May 1 894,
of some of the intrusions, the contact-alterations are comparatively
slight, and we have no such striking changes as those to bo seen
around the Bulla porphyries, for example. This therefore suggests
that the rock when intruded was not at a very high temperature,
but in the viscid condition of a mass that has undergone partial
consolidation. This is in full agreement with the evidence of the
Hiixion- structures. It is probable that most if not all of the true
fluxion-gneisses were formed under similar conditions, and we cannot
therefore expect contact-metamorphism so extensive as that produced
by the int rusion of rocks, all the constituents of which were molten
at the time of injection.
VI. The Origin of the Gneibsic Structure.
(a) Hie Igueou* Gneisses. — Before Darwin's 1 discussion of the
subject in 1846, the view of the origin of the foliated rocks by
original sedimentation had been universally held. Though the
objections Darwin advanced have now been generally recognized as
insuperable, the theory long flourished and lingers yet. In its
stead have been substituted the agencies of d) narao-mctaraorphisro,
fluxion in semi-viscid consolidating rocks, and a more local combined
fluxion and concretionary action. The first of these is that which
is most widely applicable and is the real cause of the parallel folia-
tion of rocks of very different composition over wide areas, t. c. of
all cases of regional mctamorphism. But that this is not a universal
explanation is now admitted. Thus it has long been known that
many intrusive rocks which are normally granitic in structure
become foliated around the margins and in the apophyses which run
off from them. Prof. Rosenbusch,2 for example, clearly recognizes
gneisses thus formed as well as those due to dynamo-metamorphic
action. So also do MM. Michel-Levy and Barrois.9 In England
the same theory has been extended to cases previously regarded as
due to dynamo-metamorphic action. Thus it has been applied by
Prof. Bonney and General McMahon 4 to the foliated gabbros of
Cornwall, by the latter author s to certain gncis.-ose granites of the
Himalaya, by Prof. Bonney and the ltev. Edwin Hill 6 to the banded
gneisses of Sark, and by Sir Archibald Geikie ' to many Archaean
gneisses. Further illustrations could easily be added, but this is
1 Darwin, * Geological Observations on South America,' 18-16, chap. ri.
3 Rosenbusch, 'Mikrosk. Physiogr. JJass.Gesteine,' 2nd cd. vol.ii. (1887) p.41.
3 Barrois, 4 Lc Granite de Rostrenen, sea Apophyses et sea Contacts,' Ann.
8oc. geol. Nord, \ol. xii. (1885) p. 105.
* • On the Crystalline Rocks of the Lirard District,' Quart. Journ. Geol. Soc.
vol. xlvii. (1891) pp. 483-491. (Further references given in footnote, p. 469.)
5 4 Note on tbe Foliation of the Lizard Gabbro,' Geol. Mag. 1887, pp. 74-77.
« ' On the Hornblende-Scbista. Gneisses, and other Crystalline Rocks of Sark,'
Quart. Journ. Geol. Soc. vol. xlvni. (1892) pp. 125-127, 182-137. Note by
Prof. Bonney, ibid. pp. 145. 140.
7 In discussion of Prof. Bonney and General M'Mahon's paper, op. cit.
vol. xlvii. (1891) p. 499.
Vol. 50.]
GNEISSES IN THE COTTIAN 8EQUEXCE.
265
sufficient to show that an eruptive- or fluxion-foliation is well
established.1
Kepresentatives of both the metntnorphic and the fluxion-gneisses
occur in the Cottiaus ; thus the gabbros (or zobtcnites) of Monte
Viso are due to the deformation of massive gabbros, while the
augen-gabbro-gnciss along the margin of the gabbro intrusion at
Le Chenaillet, on Mont Genevre,2 appears to be clearly duo to
fluxion in a viscid rock near the contact.
We have then to consider which of the two explanations must
be applied to the Waldensian gneisses. The field evidence at once
suggests that the structure in these is a contact-fluxion. The fact
that the rock is foliated on the margin, while often granitic in the
centre of the massif, is not by itself conclusive. The stress of
subsequent earth-movements might readily set up a deformation
along the line of contact of two dissimilar rocks. But the evidence
of the dykes is free from such doubts ; the foliation is there parallel
to the walls, and is frequently at a high angle to that of the
neighbouring schists. The dykes often have an irregular course
through the schists, but the foliation in them remains quite in-
dependent of that of the surrounding rocks. This appears to show
conclusively that in these cases, at least, tho foliation is a contact-
fluxion, and has no connexion with the dynamo-mctatnorphisin of
the district.
Microscopic examination shows the identity of the structures in
the apophyses and the massifs. In both the phenocrysts present
true erosion-structures, as well as some which — like those from the
Kepublic of Colombia discussed by Kuch 3 — may better be explained
as due to pressure-deformation. In both, the micas and other
constituents are distributed along lines of flow around the larger
crystals. Finally, there is no evidence of the production of
secondary minerals, such as invariably accompanies dynaino-
metamorphiftm sufficiently powerful to produce a molecular re-
arrangement of the constituents.
(b) The Clastic Gneisses. — If gneiss be defined simply as a
foliated rock consisting of quartz, orthoclase, and mica, then there
are in the Eastern Cottians numerous rocks to which this name
must be applied : thev were clastic rocks — now altered bv the
intrusive Waldensian gneisses. These have been previously referred
to as gneisNoid mica-schists, and one has already been described on
p. 2o9. That one serves as a convenient type, because all stages can
be traced to it from a lead-coloured schist of undoubtedly clastic
origin.
' Cases of foliation due to a kind of concretionary action on an enormous
scale are probably exceptional and local. Such, however, appears to be the
explanation of the foliation of some of the basic igneous rocks on tho north-
west coast of Lake Superior, which the writer hones shortly to describe.
2 Cole and Gregory, • Tin Variolitic Rocks of Mont Genevre,' Quart. Journ.
Geol. Soc. vol. xhri. (Ib90) p. 303.
• Kich. Kuch, ' Petrogmpbic— pt. i. : die vulkanischen Gesteine:' in Keise
k Stubel's •Geologiscbe Studien in dcr Republik Colombia/ 18i>2, p. 61.
Q. J. U. S. No. 198. t
200
DR. J. W. GREGORY ON THE WALDENSrAN
[May 1894,
The differences between the clastic and the fluxion-gneisses may
be very conveniently expressed in diagrammatic form by M. Michel-
Levy's formula?, xhus, adding the letter * to signify foliation, the
following will be the formula 1 for this clastic gneiss or gneissoid
mica-schist : —
<l>a ¥.ca2l ?>,7w.
The formula for the mica-schists of the same section, where
comparatively unaltered, will be : —
These may be compared with that for a fluxion-gneiss : —
The question therefore inevitably arises, what use is to be made
of the term 1 gneiss/ as the rocks included under this name comprise
those formed by three different modes of origin? That the term
should be used to denote a type of structure, instead of composition,
is shown by the general use of such names as gabbro-gneiss. The
(juestion now is whether the term should be restricted to the igneous
or clastic varieties. Different answers have been given, according to
which rock was the prevalent one in the district studied. Thus
M. Michel-Levy,2 working among the clastic gneisses of the Central
Plateau and Britanny, urges the necessity of limiting the term to
these, whereas Prof. Lchmann, working among the granulitic
gneisses, urges that all the altered sediments should be excluded.
In the case of so old a terra, it is useless to attempt to determine
the matter by the Morison's Pill of priority. It therefore seems
advisable to retain tho word in a general sense, and add some prefix
to denote the nature of the origin of the rock.
Consequently the writer suggests the appended classification of
gneisses, sep:i rating thoso in which foliation is an original structure
from those in which it has been secondarily produced ; the latter
series may bo subdivided according to the nature of the original
rock. Tho following table summarizes the classification and terms
proposed : —
A Metamorphic. I Altered i?n™ns rocks or Metapyrigen '-gneisses.
1 ' \ „ sediments or Clastic gneisses.
B. Igneous. Fluxion-gneisses.
1 c=chlori»e; a.^actinolite ; r=stoisito; FT«»Rphene; F, = garnet.
2 ' NoK* sur la Formation gneifwique du Morvan et Ootuparaison arec quelques
autre* regions de mdtue nature,* Bull. Soc. geol. France, «er. 3, vol. vii. (1879)
pp. 870-871.
3 From irvptytvrjs, formed by 6re.
Vol. 50.]
GNEISSES IN* THE COTTIAN SEQUENCE.
267
VII. The Age of the Waldensian Gneisses.
In Part IV. of tho present paper the evidence has hoen sum-
marized to show that, whatever may be the age of the gneiss, it is
younger and not older than the surrounding schists. If, therefore,
we wish to fix a minimum age for the rock, it is necessary first to
determine tho age of the schists. This question has beon twice
discussed in recent years by Prof. Bonney and Signor Zaccagna,
who both agree with Gastaldi, Baretti, and other Italian writers ; to
these must be added the name of Prof. F. Sacco,1 who, in a
recent paper, accepts the Laurentian and Huronian correlation of
the beds.
fllie de Beaumont and Fournet held that the schists were
Jurassic, but their arguments were not in accord with modern
methods ; their view has, however, been again expressed recently
by Prof. Stanislas Meunier ' in a map in his • Geologic Itegionale
de France.' Lory, on tho other hand, assigned the 4 schistes
lustres' to tho Trias; this ho taught in 1861, and reaffirmed
in his latest utterances.* He originally assigned 4 this age only
to the calc-schists that form the upper part of the series, but
ultimately found it impossible to separate those from the lower
mica-schists, and thus carried his line of Trias as far east as the
junction with the Waldensian gneisses near Susa. This view was
based on his mistaken identification of tho whole of tho 4 Calcaire
du Brianconnais ' as Liassic ; the lowest cargneules and dolomites
of these are now universally admitted on pahcontologioal grounds
to be Triassic* Tho schists below them are, thorofore, cither
Palaeozoic or pre- Palaeozoic. Lory would no doubt have accepted
this change ; he would have argued that all the evidenco which
made him originally assign the 4 schistes lustres ' to the system
immediately preceding the limestone series was quite unaltered,
and that this simply involved calling the schists Carboniferous or
Permo-Carboniferous instead of Trias. This would, of course, be
a mere matter of detail, and would not affect the principles involved
in the discussion.
It therefore becomes necessary to consider what are the oldest
unaltered fossiliferous rocks in the district, and what are their
relations to the Cottian schists.
Along the eastern side of the Cottians the oldest fossiliferous beds
are the Pliocenes, along the extreme edge of tho crystalline area ;
> « I/Age des Formations ophiolitique* recentes,* Bull. Soc. Belgo Geol. Pal.
vol. (1891) Mem. pp. 60-95.
a Paris, 1889, p. 430.
* ' Sur la Constitution et la Structure dos Massifs de Schistes cristallins des
Alpes occidentalea,' Con^res Gool. Internal., 4m* Seas. Londres, 1888, Compto-
reudu (1891). pp. 80-103.
* Bull. Soo. Stat Isere, ser. 2, toI. rii. (1804) p. 94 (§ 293) ; ibid. vol. t. (1881)
p. 88 (§43).
* See Diener, ' Qebirgsbau der Westalpen,' pp. 18, 19.
t2
2f3S
DR. J. W. GREOOBT ON THE WALDEN8IAN [May 1 894,
hut in the Maritime Alps representatives of all the principal systems,
from the Carboniferous upwards, occur on both flanks of the main
chain. Traced north from the Apennines and the Maritimes, the
Carboniferous beds can be followed with some interruptions along
the western slope, through Briancon to the base of Mont Thabor.
Of the age of these beds there can be no question ; they have been
described by Fournct, Lory, Zaccagna, and more recently by Kilian :
they are not very f ossiferous, but the plants recorded 1 from
Monestier de Briancon, Puy St. Pierre, Chardonnet, Col de Buffer,
etc., are sufficient to precisely fix their age. The Carboniferous is
overlain by a series of rocks described by Zaccagna as Permian,
which arc doubtless a portion of the Poikilitic series ; these beds iu
several places distinctly overlap the Carboniferous and unconform-
able* overlie the calc-schists. Thus, in Zaccagna's section from
St. Paul across the Monviso to Rocca Cavour, the Carboniferous beds
are not included, but Pointe de Mar}' is capped by Permian beds,
resting un conform ably on the calc-schists. The basal conglomerates
of the Permo-Triassic series overlie the schists and contain numerous
fragments both of them and of the igneous rocks with which they are
associated. The Carboniferous rocks, however, are in no place
found in superposition to the schists, nor are fragments of the latter
met with in the former ; Kilian has, therefore, suggested the view
that the schists are probably of Carboniferous age and represent
the altered eastward continuation of these. He says ** lo terrain
houillcr disparait a Test d'une ligne Modune-Briancon-Saint-Paul, et
stmbte ckler la place atu* tchistes lustre*." 2
This view has been strongly opjwsed by Bonney and Zaccagna,
who agree in assigning the whole of the schists to the pre-
Palaeozoic. Prof. Bonney has given * a section across the pass of
Mont Genevre and the Col de Sestrieres, in which he limits the
Mesozoic series to the upper part of Monte Chaberton, including in
the Archaean the whole of the base of the mountain below the level
of the Italian forts on the road from Cesana to Claviercs, and all
the hills on the east side of the Dora Valley.
During the present year, however, the search for radiolaria which
has been stimulated by the remarkable results obtained by Issel,
Parona, and Pantanelli in 1 aguria, has been rewarded by a discovery
by Prof. Parona which has thrown an entirely new light on the
whole question. This is no less than the occurrence of a radiolarian
schist, or 4 phthanite,' or cleaved radiolarian mud included in the
calc-schist series. Prof. Parona * has described the stratigraphical
relations of this rock, which occurs interbedded in some green and
1 Lory, Bull. Soc. Stat. Isere, eor. 2, toI. vii. (1864) pp. 26, 27.
a W. Kilian, ' Notea sur l'Hiatoire ©t la Structure gt'ologique des Chainea
alpine* de In Maurienne, du Brinnconnais et des Begioua adjaceutes,' BulL.
Soc. geol. France, aer. 3, voL xix. (181U) p. f»80.
3 yuart. Journ. Geol. Soc. toI. ilv. (1889) p. 80.
* 0. F. Pnrona, ' Sugli Schisti tilieei e rndiolnrii di Ccaana, presso il Mon-
gineTra,' Atti R. Accad. Sci. Torino, toI. xxvii. (1892) pp. 306-318.
Vol. 50.]
GNEISSES IX T1IE COTTIAN SEQUENCE.
269
reddish siliceous schists on the south side of Monte Cruzeau, and close
beside the great mass of serpentine cut through by the road from
Fenestrelle to Cesana. The point at which the beds occur is on a
line between the great mass of Triassic limestone that forms the Gran
Hoc and Roc del Boucher, with some smaller exposures of the same
rocks marked by Vasseur and Carez north of Monte Cruzeau. It
seemed probable, therefore, that the fossiliferous phthanite might
be really a member of tho Trias series folded in with or faulted
down into the schists. Prof. Parona does not consider this hypothesis
in his paper, and I therefore thought it advisable to examine the
area independently. Before doing this, however, I examined part
of the Roc del Boucher limestone and its basal graphitic beds, and
worked three times over the Triassic series of Chaberton ; but in
neither could I find any trace of the phthanite. Nor is there any
evidence that would suggest an infold of the Trias in tho schists at
this point. Moreover, in working along the Fenestrelle road from
Cesana, a few thin bands of a similar phthanite and siliceous schists
are found to occur interbedded in extremely typical calc-schists.
[Dr. Bruguatelli has announced his intention of describing fully
the stratigraphical relations of the phthanites (Purona, op. cit.
p. 306). I did not therefore attempt to trace the beds to the north,
and prefer to leave any further description till after Dr. Brugna-
telli's memoir has appeared. I must apologize to him for having
possibly to some extent anticipated his conclusions, but it appeared
absolutely necessary to insert these remarks in the discussion of the
age of tho schists.]
I was consequently compelled to abandon the hypothesis which I
went to Cesana expecting to be able to prove, and can see no escape
from the conclusion that the radiolaria are of the same age as the
calc-schists.
It is somewhat unfortunate that the only fossils found, or which are
likely to be found, are radiolaria, because their evidence as to the
age of the deposits in which they occur is very unsatisfactory. The
radiolaria are also in a very imperfect condition of preservation, but
no doubts as to their authenticity can be entertained, as Prof.
Nicholson and Dr. Hinde both express themselves quite satisfied
with the evidence of the slides prepared from the material which I
collected. Dr. Rust, who has examined slides lent by Prof. Parona,
not only identifies the fossils as radiolaria, but suggests that they
are possibly Tithonian in age ; the stratigraphical evidence is, how-
ever, conclusive against the latter opinion.1
Prof. Parona has figured a good number of the radiolaria, and
has been able to determine the presence of 21 genera and even to
identify 7 species. It is probable that better indications as to the age
of a radiolarian fauna will always be obtained by the comparison of
lists of genera than of species ; more reliance must be placed on tho
general facias of faunas than on the number of species common to
1 Par.na, op. oil. p. 316.
270
DR. J. W. 6BE00BY ON THE WALDENSIAN [May 1 894,
the two. The Cessna radiolaria include two genera peculiar to the
Palaeozoic, though there are some previously known only in the
Mesozoic. Prof. Barrois 1 has recently announced the discovery of
a pre-Cambrian radiolarian fauna ; the members of this, according
to M. Cayeux, all belong to the Monosphaeroidea. The Cesana fauna
is, however, much more specialized than this, and includes such
comparatively advanced forms as Khopalastrum. The Ordovician
fauna described by Dr. Hinde a all belongs to the Spumellaria, with
the exception of some doubtful species ; and, moreover, of this sub-
class only the two orders Beloidea and Sphaeroidea are represented.
The Cesana fauna appears of a more recent type than this, and
Rust and Parona would even place it in the Mesozoic. It includes
Bix genera of Nassellaria, while the Spumellaria are represented by
the Prunoidea and Discoidea, in addition to the Spheroidea.
Few geologists would be likely at present to argue that the mere
presence of fossils in a bed is sufficient to disprove its Archaean age ;
but the general aspect of the radiolarian fauna is strongly in support
of the view of the Palaeozoic, and even of the Upper Palaeozoic, age of
the Cesana schists, a view which was so strenuously urged by Lory
(though with a slight difference in nomenclature), and has been
re-suggested by Kilian from purely stratigraphieal considerations.
We must, therefore, conclude that the Waldcnsian gneisses are
later than beds which are probably Palaeozoic and may possibly be
Carboniferous. This gives the maximum age. The statement has
been made that pebbles of the 4 central gneiss ' occur in the conglo-
merates of the Cretaceous ; I am not aware that this has been asserted
by any competent petrologist, and as so many different rocks have
been included under this name, it is probable that some fragments
of the gneissose mica-Bchists have been mistaken for it. Dr. Gia-
notti, however, assures me that pebbles of the gneiss occur in the
Miocene at Lauriano, and the accuracy of his identification cannot
be questioned, though other geologists have failed to confirm it.
Gastaldi also says 3 that specimens of all the rocks of the Alps
occur in the Lower Miocene. This settles the latest possible date,
at least for the Paradise
The basic igneous rocks which cut through the schists would
limit the date more closely, if it could be proved that they are all
of one age. The Clavieres serpentine is later than the calc-schists
through which it cuts, and is pre-Triassic, as fragment* of it occur
in the conglomerates at the base of the dolomites ; and this serpen-
tine is far more likely to belong to the basic Beries in the schists
than to the Upper Mesozoic basic series of Mont Gcnevre. None
of the pre-Triassic basic rocks cut the gneiss, though tbey approach
1 Ch. Barrois, ' Sur la Presence de Fossilea dnns le Terrain atoique de
Bretagno,' Coniptes Rendus Acad. Sci. vol. cxv. (181)2) p. 32tf.
* G. J. H inde, ' Notes on Radiolaria from the Lower Palaeozoic Rooks
(Llandeilo-Caradoc) of the South of Scotland,' Aun. Mag. Nat. Hist, aer. 6.
vol. ti. (18tK)) pp. 40-59, pis. iii.. iv.
3 Gastaldi, Mem. dwcrii. Carta geol. Ital. toI. ii. pt. ii. (1874) p. 59.
Vol. 50.]
GXEISSBS 15 THE COTTIAX SEQUENCE.
271
very close to it. We may, therefore, conclude that the gneiss is
later than the earlier basic series. But, until it can be determined
at what period in the Paleozoic era that series was intruded, this line
of argument only confirms the previous conclusions without render-
ing them more precise.
For a more definite determination of the age of the Waldeusian
gneisses reliance must be placed on the indirect evidence afforded
by a study of the main dislocations of the district. It is now
generally admitted that the mountains in this part of tho Alps have
been formed by elevations at very different epochs, from the Carbo-
niferous (or, aecording to Prof. Sacco,1 from the pro-Cambrian) to
the Pliocene. Tho evidence for, and the influence of, the different
movements, have been recently discussed by Kilian,* Haug,3 and
Diener.4 The pre-Permiun movemeuts appear to have bceu un-
important in this district, as Dieucr has pointed out, though
Zaccagna lays much stress upon them.
The main earth-movements of the Cottians may be divided into
six groups : —
1. Tho east-and-west fold of the Northern Cottians, which has
caused the anticlinal separating the gneiss of tho Paradiso from
that of the Eastern Cottians.
2. The north-and-south faults to which are due the valleys of
Turras, and tho uppermost part of the Dora Hiparia.
3. The east-and-west compression to which is due the narrow
north-and-south chain from Uric Bouchct to the Monviso.
4. A series of powerful thrusts from the west, which has pushed
the Trias on to the ealc-schists — as in the north-eastern spur of
Monte Chaberton and in the Roc del Boucher, and has contorted
the dolomites to the north of Iiocca Bianca.
5. An enormous gabbro-intrusion (possibly laccolitic) which forms
the Punta del Lagho, Monte Tre Denti, Monto Kobinot, and Monte
delle Plate, which now occupies the centre of a great circular
amphitheatre, 2J miles in diameter, formed of the schists of Rocca
ltossa, Rocca Vergia, Rocca del Mortai, and doubtless also the Costa
di Plantin and Costa Ciarmagranda.
6. Tho intrusion of tho Waldensian gneisses.
1 F. Sacco, ' La Geo-tectonique de la Haute Italie occidentale,' Bull. Soc.
Beige Geol. Pal. toI. iv. (lb'JO) Mem. p. 28.
J W. Kilian, 4 Note* eur l'ilistoire et la Structure geologique dea Chained
al pines de In Maurienne, du Brianconnais et tics Regions adjaeentea,' Bull. Soc.
geol. France, aer. 3, toI. xix. (1891) pp. 571-661 ; and * Description geologique
de la Montagne de Lure (Bassea-Alpe*),' 1888, Ann. dee Sciences Geol. vol. xx.
pp. 110-169.
3 E. Haug, ' Lea Chainca aubalpines entre Gap et Digne ; Contribution a
l'Histoire geologique des Alpee fran^aisea,' Bull. Serv. Carte geol. France,
no. 21, vol. iii. (1891) pp. 169-1*1.
« Dieuer, * Gebirgabau der WesUlpen,' pp. 190-218.
Digitized by Google
272
DR. J. W. GREGORY OS THE WALDENS1AW [May 1 894,
With the exception of No. 5, these six divisions may be arranged
into two groups ; the first includes Nos. 2, 3, 4, and b\ the axes or
directions of which have a general north or north-westerly to south
or south-easterly range ; the second includes the transverse fold of
the Northern Cottians. The detailed work of Kilian and Haug1 has
shown that the dislocations of the Subalpine chains to the west may
also be grouped into approximately meridional and transverse series.
It is tempting to try to correlate these with the dislocations of the
Cottians, but this cannot be done, except in a very general way.
Kilian points out that in the mountains of Lure the north-and-south
series are prc-Miocene, and the east-and-west scries post-Upper
Miocene. Similarly in the Gap-Pigne area the N.W.-and-S.E.
folds are pre-Aquitanian (Upper Oligocene) and possibly Lower
Eocene, whereas the east-and-west set are mostly Helvetian (Middle
Miocene), though some are pre-Aquitanian. The same probably
holds in the Cottians : the east-and-west fold of the Northern
Cottians is apparently connected with the Paradiso intrusion, and
is probably Miocene, certainly pre-Pliocene. The Pliocene beds
of the Villafranchian stnge on the eastern flank have been raised
over 1500 feet by a movement which closed that period.a As,
however, the Paradiso gneiss was exposed before this, a fact proved
by the ovidence of the Miocene conglomerates, this Pliocene move-
ment must have followed along the old line. The crushing of the
contact-rock between the gneiss and the schists may have been
caused by such later movements.
The absence of fossiliferous Tertiary beds in the Cottians pre-
vents any such definite determination of the succession of the
movements as is possible in the Subalpinc mountains of Dauphinc.
Nevertheless a rough order may be safely established for the re-
maining five sets of dislocations. No. 5 is probably Upper Mesozoic,'
owing to the agreement of its rocks with those of the Mont Genevre
variolitic scries ; typical specimens of variolite derived from this
mass occur in the bed of the Sangonetto above Pale. Nos. 3 and 4
are both later than the Cretaceous, some bods of which are included
in the limestone series of Chabcrton. No. 2 is still later, as it has
cut through the overthrust limestones both at the Roc del Boucher
and at Chaberton. These three sets, Nos. 2, 3, and 4, are probably
more closely allied than the others ; they arc the result of enormous
lateral compression and strain, and the seconds ry foliation so fre-
quent in the schists of the district is probably due to them. The
1 Haug, op. supra cit. pp. 181-187.
a Sacco, ' II Cono di dejezione della Stura di Lnnzo,' Boll. Soo. geol. Ifal.
rol. vii. (1888) p. 160 ; see also Gastaldi. Mem. descriz. Cart* geol. Italia,
vol. ii. (1874) pi. ii.
* The latter basic series is accepted as Upper Mesozoic (probably Cenoma-
nien) on the authority of Prof. Sacco's demonstration that the Ligurian beds
containing the serpontinos of Liguria are Cretaceous and not Eocene, ' L'Age
des Formations ophiolitiques reoentes," Bull. Soc. Beige Geol. Pal. vol. v. (1892)
Mem. pp. 60-95.
Digitized by Google
Vol. 50.]
GNEISSES IN THE COTTIAN SEQUENCE.
273
schists and tbo igneous rocks of the * pietre-verdi ' group have been
foliated at right angles to the axis of compression. Though I am
not aware of any evidence that gives positive proof of the exact age
of these dislocations, it is highly probable that they are part of the
great post- Helvetian pre-Tortonian movements in which the forces
that raised the Western Alps attained their maximum intensity.
The Waldensian gneisses havo not been affected by any of the
previous movements. The differences in this respect between the
gneisses and the neighbouring schists is one of the most striking
features in the Cottians. In the gneisses the minerals are all fresh,
and the original fluxion-foliation undisturbed. In the schists the
minerals are altered, often till no trace of the original constituents
remains ; instead of the felspars being water-clear, the original
fragments are saussuriti/.ed or represented only by grains of zoisite,
while the pyroxenes have been uralitized, and the resulting pseudo-
morphs, as well as the original amphiboles, have been converted
into emaragdite. The changes in the structures and field relations
of the rocks have been still more striking ; the schists have been
intensely crumpled and contorted, folds have been inverted, and the
materials of the concave limb crushed into mvlonites ; gnnrkd
schists have been a second time crumpled, foliation has been im-
pressed on foliation, and fault has broken the continuity of fault.
It seems almost impossible to believe that the gneisses can have
remained fresh and undisturbed through the dislocations that have
produced such changes in the rocks with which they are in contact ;
this affords another proof not only that the Waldensian gneisses are
younger than the schists, but that they are later than the great
earth-movements at the close of the Middle Miocene. It is quite
possible that the gneiss of the enormous massif of the Paradiso was
intruded somewhat earlier than that of the Eastern Cottians, and
this would account for the pebbles in the Miocene. Tho low hanks
of gneiss which oven now have only a very restricted outcrop, some-
times merely on the floors of the Waldensian valleys, are most unlikely
to have been exposed during Miocene times.
In the Alps of Dauphiue the Pliocene movements are very feeble,
but this does not forbid their powerful influence in the centre of
the Cottian group, for feeble also are the movements in the Miocene
there — compared with those which elevated tho main chain of the
Western Cottians. The elevation of the Villafranchian beds has
been shown by Sacco to demonstrate an elevation of over 1500 feet,
and tho gneiss-intrusion may well have been contemporary with
this. Paradoxical though it may appear, the evidence renders it
most probable that tho Waldensian gneiss, instead of being of
Laureutian age, is really Pliocene, and, with the exception of
the Saharian and recent alluvium and the glacial moraines, is tho
newest rock in the Cottians.
74
DR. J. W. GREGOBT OH THE WALDEN8IAH [May 1 894,
VIII. Summary op Cosclusiows,
1. The Cottian Sequence consists of :—
(a) A scries of coarse-grained gneisses occurring along the line
of the Eastern Cottians ; for convenience of reference these
are called * the Waldensian gneisses.'
(6) A thick succession of schists which are gneissoid near the
junctions with the gneisses, are mica-schists at the base,
and pass upward into calc-schists.
(c) An extensive group of cpidiorites, serpentines, etc. (the
4 pietre verdi ' of Gastaldi), which traverse the lower part
of b.
(d) A series of fossilifcrous beds ranging from the Carboniferous
upward.
2. The Waldensian Gneisses. A description of their field-
relations and microscopic structure is given, and it is con-
tended : —
(a) That they occur as independent, isolated masses, and not as
a continuous band having a fixed geological horizon at the
base of the whole series.
(6) That instead of being basal Laurentian rocks, overlain by
or faulted against the schists, they are a series of igneous
intrusive rocks ; this is demonstrated by
i. The contact-metamorphism around them, both exo-
morphic and endomorphic ;
ii. The occurrence of apophyses of gneiss and aplite from
the gneiss into the schist ;
iii. The gneiss often containing large altered blocks of the
schists, and being sometimes saturated with chloritic
aud amphibolic material absorbed during intrusion ;
iv. The transgressive nature of the junction between the
two series ;
v. The failure of any of the igneous rocks, intrusive into
the schists, to cut the gneiss ;
vi. The fact that the gneiss has not been affected by the
earth-raovements which have crushed and contorted the
schists.
3. The P aradiso Gneiss. The relations of this on one margin
are also described, and it is shown that it agrees in all re-
spects with the Waldensian gneisses, except for
(a) Its greater mass.
(6) The possibility that it was in part intruded at an earlier
date.
The evidence in this case is less complete.
Vol. 50.] GNEISSES IK THE COTTIA.N SEQUENCE. 275
4. Tbe Gneissic Structure.
This is shown Dot to be due to dynamo-metamorphism, but
to be an original fluxion-structure formed owing to the intru-
sion of the rock in a viscid condition. It is, therefore, not to
be expected that these fluxion-gneisses will produce such
extensive contact-metamorphism as rocks intruded at a higher
temperature. Other gneisses in the Cottians were formed by
the dynamo-metamorphism of igneous rocks and mechanical
sediments. The example of those writers who use the term
4 gneiss ' only in a structural sense is, therefore, followed ; and
the three groups met with in the Cottians are referred to as
clastic gneisses, metapyrigen-gnoisses, and fluxion-gneisses.
5. The Age of the Waldensian Gneisses.
(a) They are later than the schists, and the uppermost member
of this series belong* in all probability to the PaUeozoic ;
this conclusion is based on :
i. The stratigraphical evidence relied upon by Lory and
Kilian ;
ii. The ovidence of the radiolarian fauna in the calc-
schists ;
iii. The schists, however, are unquestionably pre-Triassic.
(0) The gneisses have not been affected by the great Miocene
(post-Aquitanian, pre-Langhian, post-Helvetian, and pre-
Tortonian) earth-movements which have crushed and con-
torted the schists,
(c) The elevation of the marine Pliocenes to the height of 1500
feet shows that powerful earth-movements occurred in lute
Pliocene times ; the intrusiou of the Waldensian gneiss was
probably contemporary, and perhaps the cause of these.
EXPLANATION OF PLATE XV.
42
Fig. 1. Typical Waldensian Gneiss. From quarries at Bussoleno. X
The minerals shown are large, eroded, dusty crystals of orthoclase
(o), water-clear quartz-orthoclase mosaic (a>), numerous crystals of
mueeovite (m), and granules of kyanite (£).
Fig. 2. (a) Gneiss from the margin of the Paradiso massif, consisting of a
fine-grained, quartx-ortuoclase mosaic (x), musoovite (m), included
granules of epidote (e) and aggregates of zotsite (-) and chloritic
material (c).
(b) An included fragment from the adjoining ' pietre-verdi ' series,
showing the indefinite ground moss, quartz, and gluucophune (gl).
42
From the Vonto Valley, near Chiolamberto. X 4)7.
Fig. 3. Junction of the aplite-dykes with the rocks of the ' pietre-rerdi ' series;
from the Kocce Roccaglie, Angrogna Valley ; see fig. U, p. — >7.
26
Digitized by Google
276
BR. J. W. GREGORY ON THE WALDENStAN [May 1894,
Fig. 4. Part of the thickest aplite-dyke from the name locality. It consists, in
the main, of quartz-orthorlaae mosaic and band* of muscovite ; it
contains included grnins of the surrounding n^cks, like that seen in
fig. '6.
40
Figs. 5 & 6. The Contact-series at Ostana, near Crissolo, Po Valley. X
Fig. 5. The contact-rock; all the minerals are authigenoua or due to injection
from the gneiss ; the rock consols of orthocluse {o), quartz -orthoila*e
mosaic, biotito (A), and toisite aggregates (3).
Fig. fi(a). The lead-coloured mica-schists, 10U yards from the contact-
Fig. 6(b). The gneissose mica- schist near the contact; the principal secondary
minerals produced are garnets (gr), often traversed by reins of
chlorite, muscovite (m), and rutile (n).
All the figures are drawn under ordinary transmitted light
Discussion.
The President felt sure that all would join in offering a welcome
to Dr. Gregory on his first appearance at the Society, as an Author,
since his adventurous African journey ; and he further expressed a
hope that, ere long, the Society would hear something of the
geological features of Mount Kenya.
The paper contained some startling conclusions in respect to the
lowest rocks not necessarily being the oldest ; but for these we had
been more or less prepared by the work of Lawson in America and
of Barrow in Scotland. Hence there was no a priori improbability.
Tho question was whether the evidence and arguments in this case
favoured the notion of a gneiss having been intruded into schists.
He (the President) thought it was so, though without further proofs
as to age it might be merely an instance of an Archaean gneiss
intruded into Archaean schists. Thus it became important to
determine, if possible, the age of the schists. He commented on
the fact that no fauna lower than the Carboniferous had been dis-
covered in the Western Alps, and expressed curiosity to know what
had become of the older Paheozoics : the discovery of radiolaria
may possibly lead to results of importance in this direction.
But by far the most astonishing part of Dr. Gregory's paper is
the last, where ho speculates on the age of the gneiss itself, and
concludes that, owing to its freedom from the effects of earth-
movements, it is actually amongst the youngest rocks in the
Alps. On this point, more especially, he expected an animated
discussion.
Prof. Judd said that all his prepossessions were in favour of
accepting tho views of Dr. Gregory concerning the hypogene origin
of these gnoisses and their late geological age. He felt, however,
that, in a district which has undergone such great movements, the
evidence brought forward must be scrutinized with the most ex-
treme care. Ho was not satisfied that the evidence of contact-
metamorphism, of included fragments, and of apophyses of aplite
proceeding from the gneiss into the schists had been established
beyond every possibility of doubt.
Vol. 50.]
GS KISSES IS THE COTTIAS SEQUENCE.
277
Mr. Barrow observed that the paper before the Society might be
divided into four parts. The first dealt with the evidence of the
intrusive nature of the coarse gneiss; and the Author was to bo
congratulated on the careful manner in which he had gone over the
ground, and the clearness with which he had summarized his
evidence. The second referred to the contact-effecte of the intrusion.
But here the evidence was too vague to enable us to form any
opinion as to the accuracy of the Author's views. Bid he suppose
that the crystalline character of the surrounding schists and gneisses
was essentially due to this intrusion or merely modified by it?
Thirdly, the evidence of age would require most searching examina-
tion. The movements on the margins of mountains have frequently
associated fossil-bearing rocks with older crystalline schists in such
a manner as to have deceived some of our most acute observers,
and led to the conclusion that they were all of one age. Lastly,
the fact that the great earth-movements do not appear to have
effected any crushing in the coarsely crystalline rocks was not a
satisfactory line of argument as to the age of the rocks. Powerful
earth-movements frequently fail to crush more than the outer
margins of crystalline areas ; these harder rocks escaping at the
expense of the softer and often unaltered sediments by which they
are flanked. The latter, iudeed, are frequently themselves altered
to finely schistose rocks giving every appearance of a passage from
one series to the other.
Prof. Bossey said that he had only examined these Cottian
gneisses in one locality, and had found it extremely difficult to
make out what their origin might be. If fluxion-gneisses, which
was very possible, they were rather peculiar. He quite agreed
that a group of granitic rocks existed in the Alps later than
any of the crystalline schists, but that did not prove that they
were Tertiary, Secondary, or Palaeozoic. The discovery of radio-
laria in the 4 schistes lustres ' did not show that these were Palaeo-
zoic, because, if the rocks were schists, there would bo no radiolaria
remaining; and nothing was commoner in the Alps than to rind
wedges of Jurassic, or Triassic, or older but comparatively unaltered
sediments in the crystalline masses. Also the Carboniferous rock was
very apt to have its base full of material from the older underlying
rock. As to the age of the gneiss, he agreed with Mr. Barrow that
no great value attached to the fact of these rocks being uncrushed.
He gave instances, and said he felt incredulous as to a Pliocene
age, because there was no evidence, so far as he knew, of outbreaks
of igneous rock of Tertiary ago, except the basalts in the S.E. The
Permian or some part of the Trias seemed the latest possible.
Mr. A. M. Da vies said that he had accompanied l)r. Gregory on
bis last visit to the Cottians, and had seen the greater part of the
evidence on which his conclusions were based. Some of the junc-
tions (such as that at the Hoc del Pelvo) showed striking evidences
of intrusion, but there was room for much more detailed study ;
and the mountainous Dature of the district would add greatly to the
27S
THE WALDEX8IAN GNEISSES — DISCUSSION. [Ma)* 1 894,
difficulties of mapping. There was some evidence of Tertiary (or
Upper Mesozoic) volcanic activity farther west, though faulted
junctions prevented clear demonstration in the most desirable case.
There, in the Mont Genevre and Chaberton region, the presence of
Mesozoic sedimentaries enabled one to immediately recognize folds,
faults, and thrusts, the importance of which might easily be under-
estimated in the area of crystalline schists and gneisses.
Mr. Vaugdan Jennings and Dr. G. J. Hinde also spoke.
The Author, in reply, admitted the need for caution and careful
mapping. He did not think the inclusions could be segregations,
owing to their difference in composition from any of the minerals
of the gneiss and their resemblance to those of the altered * pietre
verdi ' ; segregations do occur, and are easily distinguished. No
aplite-dykes occur in the gneiss, and the aplite is mineralogically
almost identical with the selvages of the gneiss masses ; the evidence
of the Crissolo section seems conclusive that the aplite-dykes are
offshoots from the gneiss. As regards the argument from the
unaltered nature of the gneiss, it was admitted that rocks in mass
could readily escape ; but this could hardly be the case with dykes
ranging from 100 feet to 1 foot in width. The absence of pebbles in
the conglomerate tells also very strongly in favour of the recent age
of the gneiss. The interl ami nation of thin beds of the radiolarian
phthanites with the calc-schists renders it very difficult to explain
their occurrence bv anv system of infolds. He had no doubt of the
occurrence of igneous rocks of post- Palaeozoic age in the Cottians.
Quart .Joum Geol Soc . Vol . L . PI XV
Vol. 50.] CONVERSION OP 1 GREENSTONES ' INTO SCHISTS. 279
18. On some cases of the Conversion o f Compact ' Greenstones ' into
Schists. By T. G. Bonnet, D.Sc, LL.D., F.R.S., F.G.S.,
Professor of Geology in University College, London, and
Fellow of St. John's College, Cambridge. (Read February 7th,
1894.)
Last year I described some modifications duo apparently to pressure
in certain basic dykes.1 I am now able to supplement that account
by a few notes on the changes produced by tho same agency on a
somewhat similar rock which, however, in all probability, "was at
first in a still more compact condition than any of those 1 green-
stones.'
In the year 1880 I noticed, near the path leading from the
Bernina Hospice to the Griim Alp (Engadinc), a rather small mass
of a groen schist, so compact as to resemble a slate, associated with
a fairly coarse gneiss. Their relations seemed explicable on the
hypothesis of either an interstratification of materials or an intrusion
of tho green rock into the gneiss. Each supposition had its
difficulties, and my impression was recorded in the following
words : — " I can hardly believe the green rock to be anything but a
schist " (meaning, according to my knowledge at that date, a rock
originally sedimentary). I took away speciraons and oxamined
these afterwards with the microscope. The green rock presented
the ordinary structure of a fine-grained schist ; the gneiss gave some
indications of a fragmental condition. But as I supposed (as I had
been taught) that gneiss also was a metamorphosed sediment, this
was not surprising ; still it seemed strange that a rock, so little
altered as the schist appeared to be, should bo associated with one
seemingly so much altered as the gneiss. Accordingly I deemed it
best to keep the spocimens in my cabinet, and to wait for further
light.
Graduallv suspicions arose
Fig. 1.— Schistose dyke by the path {n my thafc tho grcen
to the Gr'uni Alp. schist must be a crushed dia-
base or kindred rock. Hence,
on revisiting the Engadine
Fji^^ 1 k»t summer, I took an early
^ opportunity of examining the
locality, and was speedily
fl — L convinced of the correctness
"hfflft^ • my surmise. A dyke
I. Gneiss. 2. Schistoae dyke. w^ich cutf the P10*9 makes
a low angle with the horizon,
and sends small offshoots into the latter rock. Tho appearance
of interstratification has been heightened by the crushing out of
1 Quart. Journ. Oeol. Soc. vol. xlix. (1893) p. 94.
230 PROF. T. 0. BOSKET OK SOME CASES OP THE [Hay 1894,
the two rocks. The following words written on that occasion
describe the macroscopic aspect of the green schist : — " The' rock
looks just like a slightly altered, poorly cleaved slate, the cleavage-
structuro making a low angle with the horizon and running nearly
parallel with the slight foliation of the gritty-looking gneiss. The
schist occasionally (especially in the inner part) seems less fissile
and more massive. It has also two sets of sharply-defined joints,
making angles of 75° or 80° with the horizon, and is traversed by
two or three thin veins of quartz." The thick uess of the dyke is
rather variable : it hardly ever exceeds a yard, and is generally a
foot or so less.
About a hundred yards farther on is a smaller dyke, about half
a yard thick. Here some of the gneiss is much crushed, and the
foliation of the two rocks is not always parallel, the structures in
one place making an angle of about 20°. Rather beyond this comes
a third dyke about 8 feet thick, which is less fissile and altogether
more like diabase. Others wore found in the neighbourhood, but
further details seem needless.
A specimen from the most slaty part of the first dyke (an inch or so
from the edjre) is seen on microscopic examination to be composed
chiefly of three minerals, all minute. (1) A pale green, mica-like
mineral in wavy films, slightly dichroic. It is difficult to be sure of
the extinction ; in some cases it appears to bo parallel with the
cleavage, in others slightly oblique. Placed at an angle of 45 with
the vibration-planes of crossed nicols the films give fairly brilliant
polarization-tints. Some may be a chlorite, but, the general aspect
of most of the mineral suggests a hydrous ferro-magnesian mica.
(2) A rather granular mineral of a pale yellowish colour, which
appears to be associated with an earthy dust. Some, at least, of
this is probably epidote, but sphene also may be present. (3) A
water-clear miueral in rather angular elongated granules. This
forms a kind of matrix for the other two, and resembles a secondary
felspar rather than quartz. The structure of the specimen is that
of a very fine-grained but crystalline schist, and all traces of an
igneous origin have completely disappeared. The specific gravity is
2*55.
A specimen, which exhibits a junction with the gneiss, is not
quite so distinctly foliated as the former .ie, especially for about a
tenth of an inch near the contact-surface. In this part it is more
granular and earthy-looking and is less transparent ; in one place it
has a rather streaky structure. The weld between the two rocks is
perfect, and the subsequent pressure, as a rule, seems not to have
produced separation, except here and there, where a very small
crack appears to have formed and to have been rilled up afterwards
with a greenish mica.
A slice cut from the middle part of the second dyke mentioned
above exhibits a foliated mass of microcrystalline minerals. Among
these the micaceous one already described is much the most abundant,
Digitized by Google
Vol. 50.] CONVERSION OF ' GREENSTONES ' INTO SCHISI8. 28l
but ifc occurs in rather larger flakes, and streaky patches of it are
more distinctly brown, which, however, may be due only to iron-
stains. With it a fibrous microlithic hornblende may bo possibly as-
sociated, but the amount is not large. Many blackish granules, more
probably haematite than magnetite, also occur, with a somewhat
streaky arrangement, as if they were due to the crushing of larger
grains. In this slice the clear interstitial mineral is less perceptible,
but it contains a tew rather elongated patches in which the grams
are larger, though generally composite. The mineral resembles
secondary quarU rather than secondary felspar, and in its outer
part is pierced by minute oolourless belouites. The silica percentage
is found to be 61*88, and the specific gravity is 2*72. 1
Fig. 2. — Section cat from the mvldle jtart of the secotul cft/k-e by
the jtath to the OrUm Alf».
x 20.
A slice cut from the middle part of the third dyke shows it to bo
not quite so markedly foliated, and the constituents, including the
clear interspaces, are more distinct. Of the mica a fair amount is
of a yellow-brown colour ; this has a tendency to occur in groups of
a rather tufted form. Some is greenish, and may rather be, in part
at least, a chlorite ; while not a little, in well-formed flakes, generally
Bmaller in size than the others, is either colourless or nearly so.
Dark grey sub-translucent granules (? chalybite) replace most of the
1 I am indebted to Mr. M. W. Tra vers, B.8c., University College, London,
for these determinations and that of the other specific gravities.
Q. J. G. 8. No. 198. u
Digitized by Google
282
PROP. T. G. B0N5PT OX 80ME CASES OP TTTE rM«1V 1 894,
opacite. The nature of the water-clear mineral is not easy to
determine. Some of it is more probably a secondary felspar than
quartz.
On the eastern shore of the Lago Bianco a mass of schistose
green rock is intrusive in a rather fine-grained, somewhat crushed-
looking gneiss, which also is slightly green in colour. It runs
obliquely up the hillside and must be several yards in thickneae,
but as there is no continuous section the exact figure is not easily
ascertained. This rock is coarser in texture and less schist-like
than the others. On examination with the microscope it exhibits
numerous patches and occasional streaks occupied by an aggregate
of minerals, in certain cases apparently an actinolitic hornblende, in
others a chlorite, some of the latter being fairly dichroic and changing
from a pale tawny yellow to a distinct green (a usual type). The
patches (where hornblende is common) are often speckled with
opacite. Minute mica is probably present, but is less distinct than
in the other cases.
Rather lenticular 'earthy-looking' patches (not compound in
structure) are numerous ; these doubtless represent crushed and
decomposed felspars, and in one or two, which retain some clear-
ness, the oscillatory twinning of plagioclase can be still recognized.
Water-clear grains, often pierced by minute bclonites, are fairly
common. Most of them present on the whole a closer resemblance
to a secondary felspar, though quartz also may be present. There
are granules and grains of iron oxide, the larger most like ilmenite.
A little calcite is also present. Though a schistose structure is
distinct, the rock still retains some likeness to a diabase and would
be recognized more readily as a crush-product of a fine-grained
dolerite. Its specific gravity is 2-83.
From these facts it follows that, in certain cases, a rock of igneous
origin may be so completely changed by pressure and its indirect
consequences as to be readily mistaken for a compact and not very
much altered sediment.' For this to happen it is, I believe,
requisite that the original rock should be glassy or almost in this
condition, viz. th<> segregated minerals, as a rule, should be micro-
1 The rock from the Llyn Padam district which I described in 1879 M n
black slate (Quart. J.mm. fieol. Soc. toI. int. p. S\2) is a similar case. As
rightly determined by the Rev. J. R Blake top. cit. vol. xlix. p. 4.r»fi). the ma**
is a dyke. His specimen, which he was g.>od enough to show me, places the
igneous origin of the rock beyond doubt, though whether it be a lampropbyre
(if that term bears any definite sense) is more open to question. But it
differs so widely from my specimen that at first I doubted whether they came
from the same mass. I have, however, revisited the place and found this to be the
case. I believe that if. even in 1870, I could have examined Mr. Blake**
specimen. I should have recognized it at once as a somewhat modified igneous
rock. That which T did examine (and have subsequently puzzled over many a
for I soon became less satisfied with my conclusion) was cut from n
--pen men. As in the case described above, the effects of crushing are
oonmiouom ; it is somewhat banded and curiously like a rather altered
sediment. The mierominemlogical structure is a very* unusual one. Even
Vol. 50.]
CONVERSION OF 4 flRTTEWSTONT.S ' INTO SCHIST*.
283
lithic. Whether the dominant secondary mineral will be mica or
hornblende is probably dependent upon the chemical composition of
the rock. If it be a normal basalt, we may expect the latter ; if
near the andesites, the former. It is interesting, however, to
notice that the ultimate structure of the rock apparently depend**
to some extent upon the earlier one ; for it is coarser in the thicker
than in tho thinner dykes, and in the latter becomes distinctly
more compact near the margin. The peculiar structure of the
junction-specimen 1 also suggests that it retains a trace of the
actual selvage of the dyke. This indicates, by the way, that the
structure has been acquired by direct crushing rather than by
shearing (in the strict sense of this word), for the peculiar linear
banding must have been obliterated, or at least rendered very in-
distinct, by any lateral displacements of importance.
It is also reraarkablo that this zone — the most glassy or slaggy
of the original rock —apparently has yielded less to pressure than the
part beyond, for it has a less distinct foliated structure and a
stronger resemblance to a compact, somewhat decomposed sedi-
mentary rock.
Rather compact green schists, which not seldom exhibit more or
less of a slabby structure, are common in various parts of the Alps.
They resemble sometimes the rocks described above, sometimes
now, after fourteen years of study, after having examined perhaps fifty slices
which might be helpful, for every one which I had then seen, I cannot find a
better comparison than that the structure of the supposed elate 4 resembles
that of the ground mass of some of the ehiastolite-slates,' though I admit
that it is not a good one. We have, in short, been describing specimens which
bear little resemblance one to another.
The most singular feature in my slice is the comparatively slight indication
of the efFect of crushing. The quartz-felsite exhibits (unless I err) a faint
fluxion-structure ; the porphyritic crystals of quartz and felspar are but little
broken. In the intrusive rock also the inicrofoliation is not conspicuous till
the slice is placed with the structure about hulfway between the vibration-
planes of crossed nieols, and the gradual change from the selvage to the
coarser parts (in a thickness of about one-third of an inch) is quite distinct.
Yet the fissile character of the rock, especially near the outside, is most
remarkable, and even its texture on a broken edge in not unlike that of a dark
slate. I have to thank Miss 0. Raisin, B.Sc., for a slide cut from the same dyke
(about 4 inches from the margin). In this the micropnrphyritic character is
distinct, but the groundmass more nearly resembles that of my own slide.
I am also indebted to her for slices of other dykes in the neighbourhood. A
selvage remains in a slaty dyke which occurs on the more western side of the
cutting at the northern end of the tunnel, but here no doubt could arise as to
the nature of the rock. A conspicuously porphyritic dyke, on the opposite
side of the same cutting, also exhibits a .selvage. The base of this is of a
dark green colour, and it remains dark between crossed nieols: the larger
crystals in it are but little affected. There must be something exceptional in the
effect of pressure on a compact and rather basic igneous rock. It looks as if
the micromineralogical structure was developed without much fracture of the
glassy material. Perhaps this is due to the intimate mixture of the chemical
constituents, so that the process is more like that of devitrification.
1 This remark applies also to the Wel«h hpeeimeu mentioned in the last note.
284
CONVERSION OF * GREENSTOX i > INTO SCHISTS. [May 1 894.
those noticed in a former paper.1 These green schists occupy areas
sufficiently considerable to require a distinctive name, and are
designated grunt schiefer by the Swiss geologists. Commonly
they are in association with calc-mica schists {grant schiefery kaUc-
haltig) and darkish mica-schists {tiiotujli nimerschiefer). My ob-
servations indicate the possibility that modified igneous rocks
may form a largo part of the grant schiefer. I would not go so
far as to say that the whole group consists of altered igneous rocks,
because a tuff, or even a mud derived from a fairly basic rock,
might be metamorphosed into one of these green schists, and X have
seen some cases where the association with other schists suggested
such an origin ; still 1 am inclined to believe that the iirst-named
one is the more common. In any case, it may be useful to bear in
mind that slaty rocks, which look not much more altered than
phyllites, cau be produced by pressure from igneous rocks of proper
constitution and texture.
Discussion.
Dr. C. Dtr Riche Prkller referred to the so-called 1 Taveyanaz 1
sandstone of the Glarus Alps, and also to the sernifite, as rocks
having possibly some relation to those described by Prof. Bonney.
The Authuk said that he had not had time to examine the
sernifite which Dr. Prelier had kindly shown him, but he thought
it was undoubtedly a sedimentary rock, though possibly it might
contain comminuted igneous materials. The sandstone, he thought,
must be clastic in origin.
1 Quart. Joum. Geol. Soc. rot xlix (1893) p. 94.
Vol. 50. j JIESOZOIC ROCKS, ETC. IV THE LF.POXTINE ALPS. 285
19. Mesozoic Rocks and Crystalline Schists in the Lepontine Alps.
By T. G. BoHifKY, D.Sc., LL.D., F.R.S., F.G.S., Professor of
Geology in University College, London, and Fellow of St. John's
College, Cambridge. (Read April 11th, 185)4.)
Contests.
I. Introduction
II. The Altkirche Marble
III. The Val Canaria Section
IV. Section South of the Val Bedretto
V. General Conclusion*
I. Introduction.
My communication to the Society ' On the Crystalline Schists of
the Lepontinc Alps ' 1 has elicited a paper from Dr. F. M. Stapff,*
and has been noticed at some length by Prof. Heim in a recent
publication of the Swiss Geological Survey.3 The pages of this
Journal, for more than one reason, cannot well be used for purposes
directly controversial ; so that, as I expect to find before long a more
suitable opportunity and place, I content myself at present with
remarking generally that Dr. StapfTs main argument is difficult to
discuss, because everything turns upon the exact geological position
and the microscopic structure of certain specimens, matters in which
photographs aro of little avail ; and that Prof. Heim, as will be
incidentally shown in the course of this paper, really adds nothing
to his original argument. That rests, as I stated in my former
communication, upon a correlation of certain rocks which I consider
highly improbable, and an identification of certain minerals which I
affirm without hesitation to be erroneous.
In that communication I maintained that there was (a) no valid
proof, only a jtrimd facie presumption, that the Altkirche * marble
was of Jurassic age : and (b) not only no proof at all that the Val
Piora schists were of this age, but also strong evidence that they
were much more ancient.
On the first issue I claimed a verdict of 1 not proven.' In the
hope of finding more definite evidence, even if it went against me, I
have revisited the district. In 1891 I made a brief examination of
the sedimentary rocks near the Furka Pass, in company with Mr.
James Eccles, and last summer I spent a week in the upper part of the
Urserenthal. My friend also, in the interval, went over some of the
1 Quart, Journ. Geol. Soc. vol. xlvi. (1890) p. 187.
a Geol. Mag. 1892, p. 0. Since the words above were written a second paper
has appeared in the same periodical, 1894, p. 152, to which also the same remark
applies.
1 Beitrage tur geol. Karte der Schweiz, Lief. xxv. 1891.
4 This appears to be a more correct spelling than that used in my former
paper.
Q.J.G.S. No. 199. x
287
297
299
301
286 PROF. T. G. BOITNEY ON MESOZOIC BOCKS AND [Aug. 1 894,
ground, and has supplied me with much valuable information. The
results of my work, I regret to say, are far from being decisive, and
my only excuse for laying them before the Society is the exceptional
interest of the question, and the hope that they may be useful as a
record of facts of which account must be taken in framing any
hypothesis.
But before proceeding further it is almost necessary, in order to
dissipate a confusion which I have perceived to exist, to repeat what
has been already stated in print, so far as to make clear the exact
points at issue between myself and these eminent foreign geologists.
(1) I have never denied that Jurassic rocks form a part of the
sedimentary belt in which the Altkirche marble occurs — I know the
Alps too well to do anything of the kind. Nor do I deny that the
stratigraphical evidence seems at first sight favourable to regarding
the marble as merely a peculiar member of the group of Jurassic
rocks. My position is, that such an identification proves, on a more
careful scrutiny of the sections, to be beset with difficulties, while,
so far from receiving any support from, it is contradicted by other
regions of the Alps, where the sections are clearer.
(2) I have never denied that in the Alpine chain the sedimentary
rocks, to say nothing of the igneous, have undergone, in consequence
of the mechanical disturbances to which they have been subjected, a
certain amount of structural and of mineralogical change, and might
thus be termed * metamorphic ' rocks 1 ; but 1 have affirmed, and I
now do it yet more emphatically, that the results of these changes
generally can be recognized, and are not comparable, in the case of the
later Palaeozoic or Mesozoic sediments of the Alps, with the alterations
which, anterior to these disturbances, have converted into crystalline
schists certain sediments of unknown antiquity. Hence I consider
it better, if it be desired to avoid confusion of expression and thought,
either to abstain from applying the term * metamorphic ' to the former
results or to devise a new connotation for the latter.
(3) It is also necessary to repeat (strange as this may seem) that
a transitional passage of a sedimentary into a crystalline rock cannot
be inferred from the existence of a comparatively narrow intermediate
zone in which the destructive effects of pressure have been so great
as to make it doubtful whether this represents a crushed condition
of tho crystalline rock, with slight secondary change, or a squeezed
condition of a clastic rock (especially if the fragments be derived
from the crystalline one) with a similar change. Neither can
identities be inferred from superficial resemblances, unless a micro-
scopic study shows those to depend upon a real community of
structure and composition.
1 It must be remembered that certain constituent* of rocks are more ready to
change than others. For instance, carbonate of lime very readily crystallizes.
Hence, in dealing with an apparently crystalline limestone, it is necessary to
study the rock as a whole, ana to pay great attention to the condition of other
constituents. Silicates are more useful, us a rule, than quarts, for grains of the
latter readily become enlarged and thus are apt to lose their clastic characters.
V
Digitized by Google
Vol. 50.] CRYSTALLINE SCHISTS IN THE LBPONTINE ALPS.
287
II. The Altkirche Marble.
The belt of sedimentary rocks in which this marble occurs extends
from a point on the western slopes of tho Oberalp Pass along the
valley of the Upper Reuss and across the Furka Pass into the valley
of the Upper Rhone. On the latter pass and to the east it is
bounded, on the northern side, by a more or less micaceous gneiss,
on the southern usually by a group of greenish schists, which are
followed by the micaceous schists or gneiss of the northern slopes
of the St. Gothard Pass. These greenish schists will be referred to
(for brevity) as the ' Hospenthal schists.' In this communication I
shall abstain from discussing the question of their origin, merely
remarking that as a rule they have been greatly affected by pressure
and that I rank them among the crystalline rocks of the Alps. On
the slopes, however, of the Oberalp Pass, as will be indicated below,
they do not immediately succeed the above-named bolt. Its rocks
(with the exception of the marble) are generally dark in colour
(from a dull lead- blue to almost black); the marble varies from
white to light grey. The belt of sedimentary rocks crops out
usually on the northern slopes of tho valley : good sections are not
common, so much being concealed by debris and turf.
I purpose to deal with t he subject by describing a series of sections
(the best which I could find) from east to west, over a distance
of about 11 miles in a straight line. In order to make some
approach to brevity I shall suppress all minor details of structure
and mineral composition, and content myself with saying that every
important point in regard to similarity or dissimilarity has been
carefully tested by microscopic examination of specimens collected
for that purpose. As there can be no doubt that the rocks of this
belt, in which the marble occurs, whatever be their geological age,
are sedimentary in origin, I will rofer to it, for brevity, as the
' sedimentary belt.*
(a) Section on the higher eastern slope* of the Oberalp. — This
section has been recently exposed, in the construction of a military
road leading up the mountain on the northern side of the Oberalp
Pass. That road cuts obliquely across the sedimentary belt at angles
of 20° or 30° with the general strike of its rocks, and enters on the
northern mass of micacoous gneiss some 1600 feet above Andermatt.'
The belt consists, on the northern side, of a rather dark phyllito,"
interstratified with hard sandy bands, which gradually becomes
more calcareous as we proceed southwards. In this part paler and
more crystalline- looking layers (say from an inch downwards), whicli
1 The measurement* in this paper were taken with a pocket-aneroid, and
therefore tbey are only approximate. I think the error in reading would be lea*
titan 10 feet, but the instrumental error is uncertain, as it varies from day t.u
day.
* I employ the term • phyllite ' for a slaty rock in which an unusually lai ^e
amount of a minute secondary mica has been developed, which gives a peculiar
' sheen ' to the cleavage-surfaces, i. e. one step nearer a schist than a slate, b it
still a long way from the former.
x2
PROF. T. 6. BONNET ON ME8OZ0IC ROCKS AND [Aug. 1 894,
project slightly on weathered surfaces, are interst ratified with more
argillaceous layers. On the southern side rauchwacke occurs in
irregular patches of no great thickness, being apparently not always
present. On the northern side of the belt the junction of the phyllite
and gneiss is exposed, though it is not very clenr, for it is much
troubled by quartz-veins. So far as I could see, the phyllite became
rather sandy for the last few inches, though it did not contain
visible fragments, and the gueiss was exceptionally crushed. Ou
the southern side * sericite-gneiss ' crops out, and can be certainly
identified within a short distance of the phyllite. It is possible
that here also the junction is exposed, but in this place the rocks
are so much crushed that I refrain from expressing a positive
opinion. In this section I could find no trace whatever of the
Altkirche marble, for even the most crystalline seams do not
resemble it, but they reminded me rather of the matrix in some of
the Jurassic knotenschiefer of the Nufenen Pass, etc.1
(b) Sections on the lower slopes of Oie Oberalp. — Some of these
were described in my last paper, but, as I carefully re-examined the
whole slope between the northern gneiss and the marble, clearing
up some minor details and making one important discovery, I shall
venture to describe it rather fully, though this involves a certain
amount of repetition. Time will be suved by regarding this section,
or rather group of sections, as a whole, and commencing the de-
scription at the back of the old church, some 40 or 50 feet above
the high road of the St. Gothard (fig. 1). On the northern side is
Fig. L — Section at Altkirche : length rather less titan £ mile.
N. S
1
2
3
3
4
Micaceous pneiss.
Phyllite (Jurassic ?).
Murble.
Second mass of marble.
Phyllite. etc. (Jurassic).
5 = ' Sericite-gneiaa,'
(» = Phyllite (Carboniferous).
7 = llospenthal schists.
x — Covered ground.
the gneiss, as usual, which runs up the steep mountain-slope, often
terminating in a low crag, overlooking a slight depression. The
latter is occupied, as already stated, by a dark phyllite, which can
be seen cropping out within a few feet of the gneiss : the cleavage,
which is nearly vertical, striking a little E. of N.E. The depression
1 Confirmed by examination of one of the most crystalline-looking pieces
under the microscope. Fragments occur with traces of organic structure,
probably crinoidal.
Digitized by Google
Vol. SO.] CRYSTALLINE SCHISTS IN THE LEPONTINK ALPS. 289
is bounded on the southern side by a low mound-like shoulder, which
also runs up the mountain, and can be readily traced for a consider-
able distance. On the northern slope of this shoulder the phyllite
extends nearly to the flattened summit 1 ; then, after about 3 yards
of covered ground, comes a small outcrop of a fissile grey-coloured
marble (?), followed, after about a yard, by another small outcrop
of darker rock, which appears to me on the whole to present most
resemblance to a variety of the marble very much crushed.3
In the next 4 or 5 yards are outcrops of a rather micaceous rock,
very fissile and rotten, which I consider to be most probably also a
crushed and much decomposed variety of the marble. To it succeeds
an outcrop of a rock generally similar, but less fissile, and ubout 2
yards from that is an outcrop of a rock distinctly crystalline, at first
rather micaceous, afterwards quartzose. Rocks of a like character,
but rather more calcareous, can be traced for some little distance
down the hill, roughly on the same strike. To the last-named
outcrop follows the white marble which is quarried a little below
the line of the section. On its southern side this mass forms a low
cliff 3 overlooking a depression occupied by Jurassic rocks.
I must refer once more to tho marble of this quarry. The lower
and larger opening is 10 or 11 yards wide, across the strike;
the excavation apparently being limited on both sides by a less
pure * and more rotten condition of the rock. The quarried marble
is very crystalline and occasionally is distinctly banded with seams
of mica, when it resembles locally some of the calc- mica-schist
which in other districts of the Alps forms part of the group of
crystalline schists. The rock has a ' slabby ' structure parallel to
the seams of mica, and the surface of the slabs is * fluted.' These
structures and the general aspect of the marble produce the im-
pression that when it was subjected to pressure it had already
become a crystalline rock, and this impression is confirmed by the
examination of several microscopic sections. As described in my
last paper,* we can trace this shoulder of marble for a considerable
distance up the steep mountain-side, but the section to which I
must draw particular attention occurs about 250 feet above the
high road.6 Starring northward from this shoulder of marble,
already mentioned, we cross, for about 40 yards (estimate), a
turf slope, on which chips of phyllite abound, together with
(apparently) small outcrops of the same.7 Then we come to a
1 I omitted to enter in my notes the distance of this from the northern gneiss,
but I think the breadth of the phyllite outcrop cannot exceed 35 yards.
3 The condition of both these rock* makes it impossible to stteak positively
as to their nature. Here No. 3 of the remarks made in the Introduction (p. 286)
must be remembered.
3 I halted here, because the grass was not yet mown on tho ground below,
and the age of this part of the section is not disputed.
* It contains a fair amount both of mica and of quart*.
s In which details of the microscopic structure of the marble are given,
Quart. Journ. Geol. Soc. vol. xlvi. (1890) pp. 193-196.
• See the upper part of fig. 1, p. 288.
7 I examined this slope most carefully, and was convinced that the phyllite
is in situ.
290 TROF. T. O. BONNET ON MESOZOIC ROCKS AND [Aug. 1894,
second outcrop of marble, much smaller than the other one, forming
a low craggy rib, which, however, can be followed for some distance
up the hillside before it finally disappears. Lastly, after crossing
another Blopo of turf, about 50 yards in width, we come to the
gneiss already mentioned. Thus the upper section exhibits (as was
the case in the St. Gothard tunnel) two masses of marble. Of these
tho one common to both sections is at a considerably greater
distance from the gneiss in the upper than in the lower section.
This obviously is suggestive of faulting.
Microscopic examination of the more micaceous and more quartzose
rocks mentioned as occurring on the northern side of tho marble
shows them to possess the ordinary structure of a crystalline schist
which has been subsequently somewhat modified by pressure. They
consist of quartz, j>ossibly some felspar, and mica (chiefly white) ; the
former rock contains a few grains, rather rectangular in outline, of
some rather decomposed aluminous silicate, and the mica is in some-
what larger plates and occurs in more definite films ; the latter rock
includes one or two zircons. Both are somewhat stained by a
brownish or blackish substance (probably a hydrocarbon) which
appears to be an infiltration. It must be remembered that the
marble itself becomes not only micaceous, but also quartzose, the
latter mineral sometimes dominating over the calcite, and the rock
precisely resembling one of the more quartzose calc-mica-schists so
common in the Alps. In other words, wo have to deal, in this
particular section, not with a single rock, but with a group of
crystalline schists, in which a calc-schist or marble dominates, each
presenting the aspect and structure which are elsewhere characteristic
of crystalline schists (somewhat affected by pressure), and which
I have never seen in the Mosozoic rocks of the Alps or of any other
country.
Lastly, it must ftot be forgotten that on the southern side of the
4 sericite-gneiss,' between it and the Hospenthal schists, is a belt of
sedimentary rock consisting of a dark phyllite, with some bands of
coarser material, which, on the Swiss Geological Survey map, is
referred to the Carboniferous System. Tho ' sericite-gneiss ' is
most probably a modified granite, but whatever bo its age (and this
can hardly be post-Jurassic), a study of these sections alone is
enough to show that the collocation of the various masses between
the micaceous gneiss on the north and the Hospenthal schists on
the south cannot be explained by a simple folding.
The St. Gothard tunnel, according to the map in Baedeker's Guide,
passes benoath the meadows slightly to the west of the lower of these
two sections at Altkirche. Since my return I have again examined
the series of specimens from that tunnel which are preserved in the
British Museum.1 They exhibit the following succession, going
southwards: — (1) Gneiss; ('2) phyllite; (3) marble or calc-schist ;
1 I haTe to express my sincere thank* for the facilities afforded me by Mr. L.
Fletcher, tho Keeper of the Department of Mineralogy, and for the help of
Mi . O. II. Prior. F.O.S.
Google
Vol. 50.] CRYSTALLINE SCHIST* IN THE LE PONTINE ALP8. 291
(4) phyllite ; (5) marble or calc -schist (this, I believe, corresponds
with the mass which is quarried behind the church) ; (6) lime-
stone (?) and schistose quartzite (examination of the hand-specimens
does not enable me to decide whet her these belong to the crystalline
group or to the slaty sediment aries) ; (7) gneiss ; (8) limestones with
phyllites — Jurassic ; (9) soft, whitish calcareous rock, possibly
rauchwacke ; (10) gneiss; (11) phyllite, which alternates with
gneiss or crushed crystalline schists, over about 520 metres (the
latter dominating), after which the crystalline series becomes
continuous and bears a general resemblance to that crossed on the
ascent from Hospenthal to tho St. Gothard. The northern part of
this section would correspond with the upper section seen at
Altkirche, if we may suppose the phyllite (2) to underlio the turf
between the outcrops of the northern gneiss and the first rib of
marble, which is not improbable. Of (7), which is labelled and
appears to be a gneiss, I have not seen any sign at the surface.
The limestones with phyllites (8) no doubt belong to the southern
part of the Jurassic band. The remainder of the section from (10)
onwards, which I have not quoted in detail, corresponds with the
serioite-gneiss, the dark phyllite or schistose slate, and the Hos-
penthal schists (which appear to be moro gneissose than they are
about Hospenthal).1 But this alternation of phyllites and crystalline
rocks, so far as I have seen, is not visible on tho surface. Thus the
tunnel-section confirms the observed differences between the sections
at Altkirche, and indicates a still moro frequent intercalation of
slightly modified sedimentarics with crushed crystallines than is
shown at the surface. Also it exhibits, west of the lower section
at Altkirche, a repetition of tho marble, which is seen east of it at
the surface. This strange variation in the number of times that
the marble occurs is favourablo to the hypothesis that the apparent
interstratification of tho crystalline and non-crystalline groups is the
result of thrust- faulting, such as has been described by the members
of the G eological Survey in the North-western Highlands. It must,
however, be admitted that the 4 slicing ' demanded by this hypothesis
is of a most remarkable kind, for tho tunnel at Altkirche is at the
very least more than 1000 feet below the surface, so that the * wedges '
of the older rocks driven through the newer must be unusually
long and thin.
(c) Section west of Altkirche. — This is on the left bank of the
Reuss, about a mile away from the last one. The fissile micaceous
gneiss, which forms, as usual, the northern boundary of the sedi-
mentary belt, crops out about 100 feet above the- level meadows.
Near the actual junction, the exact position of which is difficult to
determine owing to the condition of the rocks and the presence of a
large quartz-vein, begins a section, practically continuous, which
can be followed down almost to the meadows. It exhibits a dark
1 I hare not examined a good geeiton of them near Andermatt, where, ao far
as I remember, they are generally not well exposed.
2i)2 PBOF. T. G. BONNET ON MESOZOIC KOCKS AND [Aug. 1 894,
lead-coloured, slaty or slabby, more or less calcareous rock,1 such as
is coramou elsewhere in the Alps among strata of Jurassic age ; but
not a trace is seen of the Altkirche marble, and there is no reason
to suspect that it is concealed immediately beneath the water-
meadows.
(d) Section roughly north of Hospenthdl. — This is separated from
the last by an interval of rather more than a mile. Here the gneiss
(much crushed) ends at a height of about 750 feet above the river.
Beneath the last outcrop of this rock the ground for about 50 or 60
feet vertical is covered ; then begin a number of outcrops of dark,
slab by, argillaceous limestone, like that just mentioned, followed at a
considerable d^tance below, where the slope becomes less steep, by
the Ho8pcnthal schists. In one place I found projecting from the
turf some bits of calcareous rock in a very 'slabby ' condition, paler
in colour and more crystalline in aspect than is usual with the
indubitably Jurassic rock of the district. Whether it is in situ
seemed doubtful, and a small moraine is close at hand. If, however,
it be so, and is the marble (as I believe), then there is very little of
it, and this is in a very crushed condition.
(c) Section at Rmlp. — Tliis is obtained in a ravine od the same
side of the valley, which descends near the lower end of the village,
at a distance of about 11$ miles from the last one. The rocks on
the whole are well exposed ; but to obtain a complete section we
must cross the torrent, and there are even then three intervals
where the ground is covered. The section on the opposite page
(fig. 2) indicates the succession of the rocks, and does not require
niore than a few words of explanation. The marble (fairly well
represented) is a very iiagey rock (3), which takes a yellow tinge in
weathering. It corresponds under the microscope with the Altkirche
marble, and the slice exhibits a very quartzose lamina. It is overlain
by a daiker variety more like an ordinary limestone (3'). The
actual contact of the two cannot be examined, for they are always
separated by at lea^t a foot of accumulated debris, but the lower
rock seems to become slightly darker in tint as it approaches the
upper. Both rocks evidently have been much affected by pressure,
and break into slabs which vary in thickness from | inch down-
wards, sometimes hcing not more than \ inch thick, almost like
slates.3 The mass between these rocks and the gneiss above is the
usual dark lead -coloured limestone, interbanded with dark phyllitos ;
that between these and the Hospenthal schists below consists of
1 The rook is quarried for a good part of the way. Specimens have been
examined with tin* microscope: one is slightly more crystalline than usual (it
was selected for litis reiison) but is very different from the marble.
a The microscopic structure of this rock present* difficulties, which will be
more fully considered in dealing with the sections on the Furka Pass. It may
bo a crushed and stained .onditiou of the marble, but it may be only a rather
cxct pHoiitil variety ot the Jurassic limestone, aud one or two grains show a
-structure, thut is pu^ibU of organic origin.
ed by Google
Vol. 50.J CRYSTALLINE SCHISTS IN THE LEPONTINE ALPS.
203
phyllites, sometimes calcareous. The vertical distance from the
base of the gneiss to the road is about 550 feet.
Fig. 2. — Section at the hack of tJu village of Realjt, in the ravine.
1 = Micaceous gneiss.
2 = Dark limestone (70 feet),
dipping 20° N.W.
2 — The same, with greyish phyl-
lite (40 feet).
.r, = Covered ground (about 00
feet).
3' = Thinly-bedded, dull-coloured
limestone (?), 12 feet.
3 = Marble, 30 feet, dipping
40° N.W.
xa= Covered ground.
4 = Phyllite, etc, about 120 feet.
x^ = Covered ground.
7 = Hospenthal schists.
(The measurements were made by Mr. J. Ecoles. F.G.S.)
(f ) Section between tfie Oalenstock and Tiefenhach Hotels. — After
Realp is left, the road to the Furka Pass ascends much more rapidly,
at first over Hospenthal schists, but at a distance of rather more
than 1 1 mile 1 it crosses obliquely the Jurassic bolt. First comes a
little rauchwacke, which appears to occur in interrupted patches;
then rocks of the usual Jurassic type succeed, phyllites dominating in
the lower part, with quartzose bands towards the base, and the dark
lead-coloured limestone in the upper part. Beyond these comes a
brownish schist, more like one of the Hospenthal group than the
ordinary gneiss, which, however, is presently cut by the road. In
this section, which is generally very well exposed, I did not soo any
sign of the marble.
(g) Sections at and near (lie summit of the Furka Pans. — Tho road,
after passing for a distance of rather less than 2 miles over gneisses
and schists, into the details of which it is needless to enter, returns
to the sedimentary rocks. These, however, can be seen running
along the slopes below in a broad unbroken belt from the last-
described section up to the top of the pass, which is still a good
three quarters of a mile away.3 We worked in 1891 across this
1 This is as measured on tho map, not as reached by path or road.
a The road to it keeps near the northom edge of the belt, once- quittiog it
for a very short distance.
294
rROP. T. O. BONNET ON MKSOZOIC ROCKS AND [Aug. 1894,
belt from the bed of the glen to the high road, which we reached
no long distance on the eastern side of the ' col.' The stream, from
which we started, was running over the Jurassic rocks. Ascending
by the more eastern of two ravines (after examining the lower part
of the other), we passed in succession over the following rocks : —
(1) the usual dark slaty rock, with an occasional more arenaceous
band, extending for a considerable distance up the slope ; (2) a slabby
whitish marble, which has a general resemblance to that at Alt -
kirche ; (3) a darkish subcrystalline and very slaty rock ; (4) a rock
more like 2, but less crystalline in aspect, more fissile, and greyer
in colour; (5) a slaty, rather friable, lead-coloured limestone; (6) a
darker and more slaty rock ; (7) a more sandy variety of the same :
(8) the usual rather crushed and micaceous gneiss. The outcrops
2, 3, and 4 seem to havo" a steeper dip than the rocks above
and below, which obviously are Mesozoic, and their united thick-
ness is considerably less than that of either group. On reaching
the high road and going westwards we crossed back over 4, 3f
and 2 in succession, the last running at the back of a small
1 dependence' of the Furka Hotel almost on the summit of the pass,
and being quarried close to the former building.
The middle part of this section offers difficulties : 2 is the Alt -
kirche rock, 3 hardly presents in the field or in hand-specimens the
aspect of true crystalline limestone, but rather that of a slaty sub-
crystalline Jurassic rock. When examined under the microscope it
is found to consist of grains of calcite, quartz, and pyrites, inter-
spersed with black carbonaceous matter. Certain grains of the
first exhibit a peculiar structure, developed by brown or black
staining, which resembles that characteristic of echinoderms ; these
very probably are fragments of crinoids.1 Those in the matrix
generally are rather oval in form, about *05 inch long, and may be
compared (with it) to the matrix of the knotetischiefer in the Nufenen
and Scopi districts. But some larger grains of calcite, which occur
now singly, now in small clusters, including occasionally a grain of
quartz, suggest by their outlines the possibility that they are in reality
detritus from the marble. A second specimen, collected from the
above-mentioned locality by the high road, showed a similar struc-
ture, contained fragments of organisms, suggested the possibility of
detritus from the marble, and included quartz and a little felspar
apparently of d< trital origin, the latter having been somewhat en-
larged subsequently. This rock not improbably corresponds with
No. 3' of the Realp section. But No. 4 of the Furka section seems
to be a true marble, so that, if our identification be correct, we have
In re, as in the neighbourhood of Alt kirche, not only the marble
thrust through the Jurassic rocks, but also a small portion of the
latter nipped between wedges of the former.
1 As I was distrustful of my own experience, I submitted these slides to
Dr. G. .1. Iliudo. who most kindly examine! them, nnd informed me that he
had tii> doubt of the org. rigin of some of the grains.
1 that poaai! i* were preeent, but that concerning these
Vol. 50.] CRYSTALLINE SCHISTS IN THE LEPONTINE ALPS.
2<>5
South of the high road the section at the top of the pass (sot*
. 3) is clear enough, but to the north it is not so well exposed.
Fig. 3. — Section at the top of Hie Furka Pass.
1 = Micaceous gneiss.
2 = Dork limestone and phyllite?.
3 - Marble.
4 = Dark phyllites, etc.
5 = Rauohwacke.
0 = Hospenthal schists.
The rough slopes are steep, the ground is often masked by debris,
and in one or two places on the western side is occupied by small
pools or mud. Commencing on the southern side of the 4 col,' we
find that tho crags, which also rise steeply in this direction, consist
of the 4 Hospenthal schist/ and that, next to this rock, a little rauch-
wacke (apparently only a few feet thick) is exposed at the very
lowest point in tho gap. From this to the high road the rock,
which may be traced past the hotel practically without a break, is
a black satiny slate or phyllite of the ordinary type, though perhaps
the brown sandy bands are less frequent than in some of the sections
already described. On the northern side of the road we find the
Haggy marble (2),1 which can be traced for some distance westwards
with more or less interruption, and is cut again, I believe, by the
high road on this side of the summits It is difficult to say how
far the grey limestone (3) and the second band of marble (4) can be
traced in this direction. There seems to be room for them, and on
the flatter part of the broken ground north of the high road 1
thought that I identified both ; but the exposures are bad, and the
rocks are much crushed, so that it would be necessary to plot the
whole area on a large-scale map before one could bo certain. There
is, however, no doubt that the steeper and more northerly part of the
1 This and the next two numbers apply to the description on p. 294. The
Hnggy marble is numbered 3 in the woodeut (fig. 3), and the others are not
distinguished.
3 In 1893 a change for the worse in the weather prevented me from com-
pleting my observations on the western side of the pass, while in 1891 we had
ascended to the summit up the middle of tho valley, viz. kcepiug to the south of
the highroad, and thus traversed Jurassic rocks. These were 'slaty dark lead-
coloured limestones, darkish phyllite*, and rather brown sandy rocks,' bordered
in places on the south side by rauchwacke, beyond which rose the Hospenthal
schists. In the Jurassic group we found more than once the belemnites, dis-
torted by pressure, which havo been so often described from the neighbourhood
of the Furka Pass.
Digitized by Google
296 PROF. T. G. BONNET ON MESOZOIC ROCKS AND [Aug. 1 894,
slope is formed of a dark lead-coloured limestone and a slaty rock
or phyllite (as is shown in fig. 3), above which, at a height of
some 200 feet above the pass, the gneiss, being as usual rather
micaceous and crushed, makes its appearance.
The testimony of these sections and such evidence as can be
obtained by a general inspection of the district appear to me to
justify the following conclusions : —
(i) That the belt of rock, admittedly Mesozoic, varies considerably
in breadth.
(ii) That the strata of which it consists are neither abnormal in
character nor more metamorphosed than is usual in a disturbed region
with rocks of this age in the Alps.
(iii) That the rauchwacke is the soft, dusty, yellowish limestone
which is found at the base of the Mesozoic rocks in dozens of localities
between the longitudes of Olivone and Visp 1 on both sides of the
watershed of the Alps, and occurs, as is so often the case, in irregular
interrupted patches.
(iv) That the Altkirche marble (including the more quartzose and
micaceous varieties) occurs in a very uncertain fashion, sometimes
twice, sometimes once, sometimes not at all, and its thickness is
certainly variable.
(v) That in one or two sections it undoubtedly passes into more
micaceous and more quartzose schists, which correspond in all their
essential characters with members of the crystalline series3 in other
parts of the Alps.
(vi) That there is clear proof of the Altkirche rock having under-
gone, after it became a marble, much mechanical disturbance,
apparently similar in amount to that which has affected the adjacent
Jurassie limestones.
(vii) That there is nothing to suggest that the exceptional con-
dition of the marble may be due to 1 contact-mctamorphism/ and
that the rock is practically indistinguishable from micaceous marbles
which, elsewhere in the Alps, pass into calc-mica- and other schists
and form part of the crystalline series.
Thus it appears that the evidence before us does not give an
absolute demonstration of the age of the Altkirche marble. I have
failed to flud, on the one hand, a clear transition from it to the
Jurassic rock, on the other a distinct unconformity between them or
indubitable fragments of the former in the latter. Facts may bo
quoted for and against either hypothesis. That which affirms the
marble to form part of the same system as the Jurassic rocks seems
at first sight the more simple and moro accordant with the field
evidence in any single section ; but, if it be adopted, we must confess
ourselves unable to support the interpretation by evidence from other
1 I restrict mjself to regions whore I have myself examined it during the
last ten years.
2 Those which I hare elsewhere called the « upper schists/
Digitized by Google
Vol. 50.] CRYSTALLINR SCHISTS IN THE LEPONTINE ALPS. 297
parts of the Alps, or to find a cause for the mctamorphisra, or to
account for its capricious action. Instead of keeping to the realm of
law we are driven into the realm of miracle. The other hypothesis,
which affirmB the Altkirche marble with its quartzose associates to
be a portion of an old floor of crystalline rocks on which the Jurassic
rocks were deposited, and of which in process of faulting wedge-like
masses were subsequently thrust through the overlying later deposits,
can be supported on the grounds indicated above, but is open to the
objections that the general coincidence in strike between the marble
and the Jurassic rocks is singular, and the depth to which this
simulated interbedding of two masses of very different age extends,
as proved by the tunnel-sections, is unusually great. Still, if any
trust may be put in comparative petrology, as it may be called, the
difficulties in the latter hypothesis are much the less serious.
III. The Val Canaria Section.
Though it appeared to me that Prof. Heim's objections to my
interpretation of the section of the ravine iu the Val Can aria had
but little weight, I thought it well to take an opportunity of revising
our work. Of its general accuracy I felt confident ; still, as we had
not been a second time over the ground, mistakes or omissions in
points of detail were very possible. Indeed, I suspected a clerical
error in an aneroid observation, for the thicknesses assigned to the
upper rauchwacke and the schist did not agree with my general
recollection,1 while that of the lower rauchwacke was only an
estimate. The following results are, I believe, fairly correct. The
vertical height of the outcrop of the upj>er rauchwacke is about 520
feet, of the schist 250 feet, of the lower rauchwacke 400 feet. I
can add little to the account of the schists already given, for unfor-
tunately they were not nearly so well exposed as they had been in
1889. A huge mass had fallen from the crags of rauchwacke
(upper) on the right bank of the ravine, and its bed was completely
buried by debris for a considerable distance below. Still, I was able
to investigate one or two details of some little importance, especially
as to the relations of the rauchwacke and the schists. The junction
of tho upper mass of tho former rock with the top of the latter is
not easily determined with precision, for the rauchwacke at this
part contains flakes of mica abundantly, is much smashed about,
and is very fissile. The schist, seemingly a variety of the disthene-
schists,* is twisted, quartz- veined, apparently includes little lcnticles
of the rauchwacke, and presents an aspect very suggestive of
* mylonitic ' action, that is to say of the existence of thrust-planes.
The junction of the schist with the lower mass of rauchwacke is not
1 It was, however, the latter rather thau the former which was in fault
3 I retain the name for reasons given in the last paper ; but it must be
remembered that disthene (or kjanitc) is commonly only n microscopic con-
stituent, and the rock is a mther soft and friable schist, chiefly consisting
of two species of mica (see Quart Journ. Geol. Soc. vol. xlvi. p. 227, for
description).
Digitized by Google
298
PROF. T. G. BONNEY ON MESOZOIC KOCK8 AND [Aug. 1 894,
very well exposed, but the former (here a calc-schist) is much
crushed and quartz-veined.1 Prof. Heim denies that the section
affords any evidence of thrust- faulting. What constitutes evidence
is a question on whioh different opinions may be entertained. I can
only say that I have not often seen anything more suggestive of
thrust-faulting than the condition of the rocks just at the junction
of the schist and rauchwacke,- and in such matters I am by no
means a novice.
Our section, made in 1889, exhibits three bauds of black-garnet
schist which differ in thickness. On this occasion I could find only
two, one being buried beneath the dc'bris. The higher was a little
more than 00 feet (vertical) below the top of the mass of schists,
the lower approximately 20 feet above the bottom.3 A comparison
of my notes mado on the two occasions leads me to the conclusion
that the missing band is the middle one in the published section.4
Tf so, it is for those who advocate the hypothesis that the schists
and rauchwacke form a simple trough of Mesozoic rocks to account
for this difference in the distances of the black-garnet schist from
tho bottom of the said trough. In any case, how are we to explain
tho presence of three bands of that rock ? There may be ' luck in
odd numbers/ but they are out of place in a transverse section of a
simple trough. Prof. Uoim cannot appeal to a fault to remove
the difficulty ; for if once he lets a fault ' in at the door,' he will
find that the Jurassic hypothesis 4 flies out at the window.'
On this occasion I examined more minutely and for a greater
distance the schists above the upper mass of rauchwacke. It is,
however, needless to give all the details. A 1 disthene-schist,' which
differs so slightly from those in the group of schists below, that with
a little more crushing it would be indistinguishable, occurs more
than once, and, from about 30 feet vertically above the top of the
rauchwacke, bands of it are associated with gneiss or mica-schist
containing actinolitc.5 About*. 10 feet above the rauchwacke is a
garnet-bearing schist which macroscopically reminds us of the black-
garnet schist8 already meutioned, though the garnets are red and
the mica is much moro * silvery.* But in other localities I have
1 This is within about a dozen feet of undoubted rauchwacke. So greatly are
the rocks * troubled 1 near the actual junction that it is difficult to determine
whether a very small outcrop in the interval is crushed schist or crushed
rauchwacke, but I think it is the former. The latter rock hereabout* contains
very small bit* of silvery schist with clastic mica-flakes, but no large fragments
as i* dues at. the top of the higher mass.
- As stated in my paper (Quart, Journ. Qeol. Soc. vol. xlvi. p. 209), I do not
consider this to be the only evidence of thrust-faulting.
3 It was 230 feet from the top. The junction of the schist and lower rauch-
wacke, as said above, cannot be determined with absolute precision.
4 Op. tupra cit. p. 210, fig. 5.
s That is, with rocks of the type to whioh, for descriptive purposes, I have
given the name of the ' Tremola schist.- .'
• Op. cit. p. 2tH». Mv observation* on thi- .m- >n mud.' me doubtful a* to
between ^^^Ht^^^^S* la aohist* *— tho
uppermost one in fig. G, op. a ~* ab8ence immaterial
to the main question.
Vol. 50.J CBYBTaLLIHE SCHISTS IN THE LKFOKTIXE ALPS. 299
seen the garnets in this rock distinctly red and the silvery mica
exceptionally dominant. I postpone any further inferences from
this Val Canaria section till I have described another district
IV. Section South of the Val Bedretto.
The schists, of which the northern face of the range on the side
of this valley, nearly as far as Faido, is composed, ore mapped by
Von Fritech as part of the mass to which those of the Val Piora
belong. In order to compare the two I went from Rodi Fiesso
(3110 feet) to the neighbourhood of the Carapolungo Pass (lying,
roughly, S.S.E. of the lower end of the Lago di Ritom). From a
short distance above that village the path, which ascends steeply to
the Lago di Tremorgio (5907 feet), traverses schists like those of
the Pian Alto,1 having streaky bands of dark mica, with brownish,
more quartzose seams and yellowish streaks of caloite or crystalline
calcareous rock. After passing the lake, the path, which mounts
the steep slopes on its right bank, crosses similar rocks ; but I found
fallen blocks of black-garnet schist and one or two small outcrops
of it in situ : for instance, at about 700 feet above the level of the
lake. At the top of these slopes (about 160 feet higher) we come
to the ' Campolungo,' a grassy plain or hollow excavated in a mass
of white dolomite. At its western end, below the actual Campo-
lungo Pass (7595 feet), the dolomite exhibits a fold, extraordinary
even for the Alps. As it crops out from the turf it assumes this
shape — — being flanked by the dark schists on the south and
partly overlain by them on the north. But at the eastern end of
the hollow, where the path to Faido (which I followed) crosses a
high spur from the main range, the dolomite appears to be regularly
interbedded with the schists.3 North of the pass (7041 feet)
(nameless on the map) the schist seems to rise from beneath tho
dolomite and forms a ridge in which the rocks obviously correspond
with those traversed by the path below, in ascending from the Lago
di Tremorgio ; the culminating point on this ridge is about 400 feet
higher than the pass. On the south side of the latter the dolomite
becomes flaggy and micaceous for about a dozen or 14 feet, and
then changes rather suddenly into a mass of schists which bear a
general resemblance to the ordinary dark-mica schists of the Val
Piora, and contain some seams of typical black-garnet schist. This
4 dolomite ' consists of a well-bedded group of strata, which vary
slightly in character and probably in composition. Sometimes they
are pure white, sometimes greyish, sometimes yellowish. Tremolite
is often abundant, the crystals not seldom being over 2 inches in
length, and fine masses can be readily picked up. The mineral
appears to occur in rather irregular lenticular seams. I have
recorded in my notebook full details of tho section from the one
1 Op. eit. pp. 199-203.
* The simplest explanation is that the flat curve of the dolomite become*
more pointed towards the east and is pushed over to the north, so the beds on
this side (apparently below) are port of the mass which overlies it on the south.
300
PROF. T. 6. BONNET ON MESOZOIC BOCKS AM) [Aug. 1 894.
mass of schist to the other, hut think it needless to publish them.
The point of main interest is this — that a group of stratified
saccharoidal dolomites or marbles, very different in character from
the rauchwocke, is associated here, apparently in due sequence, with
schist indistinguishable from that in the Yal Piora, and from some of
that in the Val Canaria ravine. A similar dolomite or marble is
interstratified in the Binnenthal with the dark-mica schists of that
locality, in which also the black-garnet schist occurs, and all these
rocks as a whole appear to me insejKirable from the schists, generally
calcareous and micaceous, which extend along the Pennine range
far away to the west, by the districts of the Simplon, of Saas, and of
Zormatt. not to mention places yet more distant.
From these and other investigations I draw the following con-
clusions and inferences : —
(i) That the dark-mica schist and the black-garnet schists
(though the latter are less frequent and the minerals not quite so
large) on the south side of the Val Bedretto cannot be distinguished
from the rocks which bear those .names on the north side of the
same valley.
(ii) That in the one case they are associated with much sacchar-
oidal dolomite or marble, in the other with calc- mica-schists and
some bands of marble. Of these rocks also hand -specimens might
be collected which very often would be indistinguishable.
(iii) That in the latter locality thin bands of disthene-schist
( i. e. the two-mica-schist) also occur. These, however, I did not
see in the Campolungo district, but they exist farther west on the
Nufenenstock.1
(iv) Hence, if the schists north of the Val Bedretto (Val Canaria.
Val Piora, etc.) are Jurassic rocks, so are those south of the same
valley.
(v) But the group of schists, etc., south of the Val Bedretto can be
traced westwards by the Nufenenstock and its vicinity to the
Binnenthal. The dark-mica schists maintain the same general
character; in the Nufenen district they are associated with black-
garnet and so-called disthene-schists, in the neighbourhood of Binn
with black-garnet schist and dolomitic marble. Hence these schists,
etc., are also Jurassic.
(vi) But the rauchwacke (Triassic) in the Val Piora, Val Canaria,
at Airolo, on the Nufenen Pass, and in the Binnenthal contains
fragments of one or more members of this group of rocks, e. g. the
dark-mica-, the disthene-, and the ordinary calc-mica-schists.2
(vii) Hence these Jurassic rocks are pre-Triassic, which, as Euclid
says, is absurd.
1 Quart. Journ. Geol. Soc. vol. xlii. (1893) p. 80. Very probably they do
exist about Campolungo : I speak only of what I have myself seen.
1 It in true that I have not yet succeeded in finding the black-garnet schist :
but though to lay on the table a piece of rauchwacke containing this rock
would be tempting as a coup dr theatre, I hare never cared to spend much time
or go out of my way to search for it. When of three kinds of rock, inseparably
associated, two occur in a conglomerate or breccia, the positive argument resting
Digitized by Google
Vol. 50.] CRYSTALLINE SCHISTS IN THE LEPONTINE ALPS. 301
V. General Conclusions.
After studying the sections which have heen described above, I
spent some time in refreshing my memory of the i Biindner schicfer,'
especially in the defiles of the Via Mala and the Scorn, and in care-
fully examining, by no means for the first time, cases where Meso-
aoic limestone, yet farther to the cast, is infolded in crystalline rocks.
As the result, I repeat, if possible more emphatically than I have
ever done before, that the Mesozoic phyllites, such as those in the
Thusis district,1 though bearing every indication of having been
subjected to severe pressure, are readily distinguishable from the
dark schists in the (upper) Crystalline group : the impure limestone
and hard sandstones interstratitied with the former, from the calc-
mica-schists and the quartz-schists respectively, which form parts of
the latter ; and that the larger and purer masses of Mesozoic lime-
stone or dolomite, when they occur, notwithstanding their general
correspondence in chemical composition, are as different as they well
can be from the marbles and dolomites which are associated with
the above-named crystalline schists. The former, though often
brecciated, sometimes almost shattered by pressure, are compact-
looking, the latter saccharoidal. The only difficulty which arises in
distinguishing the two groups of rocks is one merely local, when
they happen to be exceptionally crushed in titu. The differences in
microscopic structure are not less marked than in the macroscopic
aspect.
Since my visit to the Alps in 1889 I have made two fairly exten-
sive journeys in that chain (the former also in company with Mr. J.
Eccles ), in course of which I have 4 sampled ' the rocks bearing on
these questions in many places, from the Val des Ormonds on the
west to the Bernina Pass on the east, besides working at crystalline
schists and slaty rocks in other countries. Observations in the field
have been checked and tested by study with the microscope, using
it not so much for micro-mi neralogical as for 4 pathological ' purposes,
with the result that I am more than ever convinced of the gener.-d
accuracy of the conclusions which were expressed in my former
paper * On the Crystalline Schists and their Relation to the Mesozoic
Rocks in the Lepontine Alps.'
Discussion.
Dr. J. W. Gregory remarked that the paper was a valuable con-
tribution to an important controversy, as it contained three new
on their presence completely efface* the negative argument founded on the
absence of the third, in any discussion as to the relative age of the two group*.
Moreover. 1 have found fragments of black-garnet schist in a breccia at the
baee of the admittedly Jurassic rocks of the Alp Vitgira (pp. cit. p.
Further examination enables mo to speak yet more positively on this point than
1 did in 1890.
1 I accept these as Mesozoic on Prof. Heim's authority, but have not myrelf
attempted to fix their exact position. I am quite certain that they are much
later than such rocks as the crystalline schists of the Pennine Alps.
Q. J. G. S. No. 199. y
Digitized by Google
302
MESOZOIC ROCKS IN THE LEPONTIKE ALPS.
[Aug. 1894,
sots of facts. The association of quartz-schists with the marble
was a fact which told strongly against its Jurassic age, though the
occurrence of a double series of the marbles and their repeated re-
appearance to the west did look like interstratiHcation. At llocca
Bianca in the Cottians there are saccharoidal limestones in com-
paratively unaltered phyllitos, and calcareous masses appear to be
liable to more thorough alteration than the argillaceous beds in
which they may occur.
The Author said that he quite agreed with Dr. Gregory as to the
comparative ease with which metamorphism took place in limestone.
Still ho thought it highly improbable that a true saccharoidal
marble would be interstratified with a phyllite. He quoted cases to
show how mistakes might arise, and said that, though his experience
was very large, he had never seen an instance of such inter-
stratification.
Vol. 50.]
THE GEOLOGY OF MOXTE CHABERTOX.
303
20. The Geology of Monte Chabertox. By A. M. Davies, Esq.,
B.Sc., F.G.S., and J. W. Gregory, D.Sc., F.G.S. (Read May
9th, 1894.)
In the study of the geology of the Cottian Alps the problem that
has given rise to most difference of opinion is the age of the beds of
serpentiae and 1 pietre verdi ' which occur so abundantly among
the schists of this district. Most geologists now admit them to be
altered igneous rocks, though the theory of their being bedded
sediments still lingers in Italy. As to their age, however, there is
much greater uncertainty, so that in spite of all the work that had
been done in the Cottians, when the subject was considered in 1890
in the description of the Variolitic Rocks of Mont Genevre, it was
only possible to conclude that u we must iu fairness merely style them
Post-Carboniferous until further evidence is forthcoming. The
locality that offered the best prospect of the solution of this question
seemed to be on the flanks of Monte Chaberton, the great dolomite
mass on the north side of the well-known pass of Mont Genevre.
Here a typical series of the intrusive rocks is associated with stratified
bods containing three distinct sets of fossils, namoly, those of the
radiolarian phthanites of Cosana, the Gyroporella and other Triassic
organisms of Clavieres,9 and those hitherto known only from some
fallen boulders on the eastern talus-slopes of Chaberton. The age of
the first and last of these was uncertain, and it was necessary to
determine that of the last before any great advance could be made.
The fossils in the boulders had been found on two occasions ; a
few were collected by the members of the Societe geologique de
France, during its excursion to the mountain in 1861 3 ; a larger
and better series was obtained by Michelotti and is now in the
Pisa Museum. These were described by him in 1877, and deter-
mined as of Silurian age * ; the schists of the district were therefore
assigned to the pre- Palaeozoic. Neumayr re-examined Michelotti's
specimens and identified them as Cretaceous.5 The fossils, however,
had never been found in situ, and the bearing of this change of view
on the age of the main dolomite series was therefore very uncertain,
nor could any positive objection be urged against either the views of
Lor}-,* who included all the dolomite in his Uassic 4 Calcaire du
1 Cole & Gregory, Quart. Journ. Geol. Soc. vol. xlvi. (1890) p. 323.
• JL Diener. Der Uebirgnbau der Weetalpen,' 1891. p. 18.
j 1 Reunion extraordinaire a St. Jean de Maurienne,' Bull Soc. geoL Prance,
!Att>l.XTiii. (1861) p. 77<J.
' U Geataldi, • Sui foaaili del calcare dolomitico dol Chnbcrton (Alpi Corie)
41 da G. Michel0ft Atti R. Accad. Line. ser. 2, vol. iii. Mem. (1876)
Jpiai. pla> i-fr ^
i. Bit&Mr-J^j Fr. Teller, ' Ueberbliek iiber die geologischen
liltm** eiiies -Hi-rli.-n Kiutenlander,' pt. iii. Denkacbr. d. k.
*d. Wiswiuich {lsS<>) pp. 404-405.
• 'Stratigram' Qrawe et Cottiennes,' Bull. Soc. geol. France,
ifefeMription geologique du Dauphiiio,' §§ 256
i ■ ;i. (1864) pp. 14 & 72.
T 2
.304 MESSRS. A. M. DA VIES AND J. W. GREGORY [Aug. 1 894,
Brianc/Mmais ' ; those of Zaccagna and Mattirolo,1 who included
them in the Permian and Trias ; those of Gastaldi,* who regarded
the Calcaire du Brianconnais as made up of Lias, Trias, and Car-
boniferous ; or those of Kilian,8 who regards this as composed of
Trias and Lower, Middle, and Upper Jurassic.
One of us having failed on a previous occasion to find any trace
of the limestones on the pass of Mont Genevre, we commenced our
search on the eastern clitFs of the mountain. We struck up the Grand
Vallon, which cuts into the eastern face of Monte Chaberton ; we
climbed Mont Sisnicres and thence up the north-eastern crest to the
26'20-metre stone man. About this point we found numerous fossili-
ferous boulders, some of which also occur near the entrance to the
Grand Vallon ; the beds from which we thought it probable that
these had fallen were inaccessible on this side. We therefore moved
to Bourg Mont Genevre and thence climbed Chaberton up the valley
of the Gr. Baisses. We could find only Triassic limestones on the
western slopes, but succeeded in discovering tho coralline and shelly
limestones in situ on the north side of the valley of R. Clos des
Morts, just above a ruined sheepfold east of tho Col de Chaberton.
(See Map, p. 309.)
Figs. 1 & 2 illustrate the mode of occurrence of these limestones ;
they are much contorted, and have been let down by faults into the
Triassic dolomites which arc not especially crumpled. In places, as
shown in fig. 2, the shelly limestones are much contorted, and overlie
the uncontorted dolomites. There is therefore no doubt that the fossils
do not belong to the dolomite series, but to one of later date, and that
they have been preserved owing to their having been faulted down
into, or across on to, the Trias. As some name for these beds is
desirable, we propose to call them the 'Clos des Morts' Limestones.
We made a considerable collection of the shelly limestones, but
the fossils are so fragmentary that Mr. R. B. Newton, F.G.S., of
the Geological Department of the British Museum, is unable to deter-
mine any of them. We are none the less obliged to him for the care
with which he has examined the specimons.
The corals, however, are more satisfactory : they all seem to
belong to one species, which we regard as the 6ame as that found
by Michelotti in the Valle della Vermanagna, on the northern side
of the Col di Tcnda. This was identified as a Cyathoj>hyllum.*
Noumayr has pointed out the erroneous nature of this determina
tion, and sections made from specimens collected by us show that
it is one of the Astrcridtr and belongs to the genus CalamophyUia.
As one of us has had recent occasion (in connexion with the Indian
1 ' Sulla geologia delle Alpi occidental!,' Boll. R. Comit. geol. Ital. toL xviii.
(1887) pi. xi.
3 • Sui rilevamenti geologici fatti nelle Alpi piemontcei durante la campagna.
del 1877,' Atti R. Accad. Linoei. eer. 3, vol. ii. Mem. (1878) pt. ii. p. 959.
* ' Structure gtologique dee Chaines alpinea,' Bull. Soc. g£ol. France, ser. 3
vol. xix. (1891) p. <Uf>.
* B. Gaetaldi, * Su alcuni foasili paleozoici delle Alpi marittirae e dell*
Apennino ligure studiati da G. Michelotti,' Atti R Accacf. Lincei, »er. 3, vol. i.
Mem. (1877) pt. i. pp. 122-123 & pi. i.
Digitized by Google
Vol. 50.]
ON THE GEOLOGY OP MONTE CHABERTON.
305
Jurassic Corals) to revise the European Calamophyllur, we have the
less hesitation in referring the specimens to Calamophyllia fenestrata,
Iteuss.1 The specimens agree in mode of growth, the thickness of
the walls, the number of the septa, and the coarseness of the
dentation. The prominence of the collerettes is well shown in one of
NORTH SIDE of the VALLEY OF R. CLOS Ota MOKTS.
[ 1 Trtas.
Utttffl Crtttueent, A Shrlly Limeiltme. \ Clos ifts Mttrts
b Cora/ Rerf. ) Linitttontt.
F Faults.
[This shows the Clos des Morts Limestones faulted into the TriAssic dolomites.
The direction of the lines in the dolomites indicates bedding.]
Fig. 2. — Crumpled Clos des Morts Limestone* carried by a thrust-
plane on to unconiorted dolomite. (North side of the valley of
li. Clos des Morts.)
> 8.
a = Black shale. T = Thrust-plane.
b~c — Triaasic dolomite.
1 A. E. Ton Beuss, ' Beitrage zur Charakteristik der Kreideachichten in den
Oatatv ^^^Hfe? im Gosauthale und am Wolfgangaee,' Denkaehr. d. k.
Wien, toL Tii. (1854) p. 105, pL t. figs. 20, 21.
A. M. DA VIES AHD J. W. G RE GOBI [Aug. 1 894,
Miebelotti's figures {op. jam eit. pi. i. fig. 2), and the septa in a
weathered specimen collected by us (Brit. Mus. No. K. 2374) in the
Talley of the Clos des Morts.
CalamophyHia fenestrate, Reuss, is the typical species of the Gosau
Beds, and it is therefore interesting to find that we are driven to the
same conclusion by the study of the coral as that which Ncumayr
reached from the examination of Michelotti's gasteropoda. We
are quite conscious that to maintain the existence of Cretaceous
deposits in the Western Alps is a reactionary step, especially in view
of Kilian's 1 recent refusal to admit any of the Monte Chaberton
limestones as later than Jurassic, and Br. Diener's 3 apparent re-
tractation of this view in a recent letter ; he had previously accepted
it, and claimed that the fact " was the most remarkable phenomenon
in the geological structure of the Western Alps."' Our profound
faith in the late Melehior Neumayr's soundness of judgment and
especial qualifications for expressing an opinion on this subject had
been somewhat shaken by Kilian's doubts. The field evidence,
however, has clearlv shown that the coralline and shellv limestones
are certainly post-Triassic ; whereas Kilian's view seems to be
based on the correlation of these beds with those near Oulx, which
have yielded the Myophoria described by Portis.4 The latter
horizon is unquestionably rightly assigned by Portis to the Trias :
the Diplopora (Schafh.,non Young, i.e. alga, non bryozoon) associated
with the Myophoria settle that point ; but this bed is the represen-
tative of the (fyroporeZ/a-limestone at the base of the Chaberton
series, and not of the limestones faulted down into the dolomites.
The question then arises, is this band of limestone the only
representative of the Cretaceous in the Cottians ? We think not, for
the Vermanagna limestones must belong to the same horizon as those
at Chaberton. A third representative is more doubtful, but judging
from Kilian's 6 description of some limestones from Dorgentil, south
of Moutiers, we should not be surprised if they also have gained
their association with Jurassic deposits only by later dislocations.
We had thus determined the first of the two problems for which
we had visited Monte Chaberton, for by proving that the coralline and
shelly limestones are not part of the dolomite series, and are probably
of Cretaceous age, a fairly complete time-scale has been established.
Let us next consider the relations of the associated igneous
rocks to the various divisions of this time-scale.
The views held as to the nature and ages of these rocks are very
varied. Those who regard them as metamorphosed sediments
1 W. Kilian, ' Notes sur rhistoire et la structure geologique des Chaine* alpine*
de la Maurienne, du Brian cjounais et des Regions adjacente*,' Bull. Soc. geol.
France, ser. 3, vol. xix. (1891) pp. 618-620.
3 Quoted by Kilian. ibid. p. 620.
* K. Diener, * Per Gkhir^sbau der Westalpen,' p. 19.
4 A. Portia, « Nuore localita fowilifere in Val di Suss,' Boll. B. Com. geol.
Ital. toI. xx. (1889) p. 175.
4 W. Kilian, 4 Sur le Lias de la Savoie,' Bull. Soc. geol. France, aer. 3,
vol. xix. (1890), Opt. Rd. Seance*, p. xxvi.
Digitized by Google
Vol. 50.]
ON THE GEOLOGT OF MONTE CHABERTON.
307
naturally class them as of the age of the rocks among which they
occur ; they therefore regard most of them as pre-Palaeozoic, while
t he older Italian geologists, such as Gastaldi, and Gervais and Sterry
Hunt, claimed them all as of this age. A later and smaller part of
the series has been generally considered Tertiary, but Prof. Sacco's
detailed work gives reason for showing that this later series may be
Cretaceous. Those who regard these rocks as intrusive are less
pronounced in their judgment as to the age, and though generally
accepting the division into an ancient and recent series, they have
even sometimes called this into question (Cole and Gregory, op. eit.).
The first point to be settled was whether the mass of serpentine
cut through by the road at Clavieres occurred in the calc-schists,
in the dolomite, or between the two (as in Prof. Bonney's section ').
The slopes at Clavieres are too much covered by talus, and too
near the Italian forts, to tempt one in that direction, so we
struck round the Bois de Chaberton, hoping to find tho same bed
exposed in the Grand Vallon. (See Map, p. 309.) We soon came
upon the serpentine, and determined two points about it : —
(1) That some tufas in the base of the Triassic limestones
contain many fragments of the serpentine. Both the field evidence
and examination of thin sections showed that the rock containing
these is a true tufa and not a fault-breccia. This settles the pre-
Triassic age of the serpentine ;
(2) That the serpentine is intrusive into the calc-schists, as it
here occurs in them, as it cuts across the strike of the schists, and
as there is fairly well-marked contact-alteration on each side of the
serpentine.
Elsewhere, however, on the mountain the Triassic dolomites are
cut through by some sheets of schistose ' pietre verdi ' ; these may be
seen in two places in the valley leading northward from the pass of
Mont Genevre to the Col des Trois Ireres-Mineurs. The first is by
a crag above and to the wost of Gr. Baisses ; the relations of the
•greenstone' to the basal quartzite of the Triassic series here is
unquestionably that of an intrusive igneous rock. The second is
beside the path leading to the Col de Chaberton, a little to the
north of the 2146-metre point ; here the evidence of intrusion is not
so plain. Two other similar masses of the « pietre verdi ' occur 011
the northern arete of Chaberton between the summit and the Col de
Chaberton. This is indisputable evidence that some of the igneous
intrusions are post-Triassic.
It is advisable, therefore, to examine these rocks somewhat
closely, in order to see whether it is possible to gain from them
any guidance in determining the age of the intrusive rocks of the
•pietre verdi' series elsewhere in the Cottians. At Chaberton
there are two main types : the serpentine which we now know to
be pre-Triassic, but later than the 'schistee lustres,' has been
previously described 2 ; but the later igneous rocks are so crushed
as to be at present unrecognizable.
1 • Two Travenes, etc.,' Quart Joorn. Geol. Soc. toI. xIy. (1889) p. 80.
3 Cole & Gregory, ibid, rol iM. (1890) p. 306.
Digitized by Google
30 S
THE GEOLOGY OF MONTE CHABERTOJT. [Aog. l8o4-
We have examined microscopically three specimens, two from the
greenstone-schists a little to the north of the summit of Chabertou,
and one from the dyke by the bed of a stream north of Gr. Baisses.
The former consist mainly of lines of chlorite separated by bands of
quartz, with a little authigenous white mica and some fragments of
plagioclase ; in one of the specimens there is an enormous amount
of secondary quartz. The dyke by the stream consists also of much
chlorite and quartz, with patches of a quartz-zoisite-calcite aggre-
gate ; there is, moreover, a good deal of titauoferrite passing into
leucoxene. These rocks belong to the series which includes the
appeninite, besimaudite, ovardite, etc., of some writers on the
district. They are doubtless altered basic igneous rocks, probably
crushed epidiorites. The only name, however, which we feel
justified in attaching to them at present is that of quartz-chlorite
schists or greenstone-schists.
We hope to consider the correlation of these two sets — the older
Clavieres serpentine and later chlorite-schists — with the 4 pietre
verdi' of other localities in the Cottians, in a more detailed account of
these rocks and their distribution. But it may be worth mentioning
here the probability that there is a third group of basic igneous
rocks in the Cottians, which are of still later age. The gabbros,
diabases, and porphyrites of Mont Gen^vre, and of Rocciavre (north
of the pass of Fenestrclle), may belong to this age ; there is evidence
suggesting that the gabbros of the former locality are intrusive
through the serpentines at Punta Rascia.
The Earth-movements of Monte Chaberton.
No description of this mountain would be complete that omitted
reference to the folds, faults, and thrust-planes that have combined
to render its geology so complex and interesting. We should have
wished to possess a large-scale map, and carelully work out the
whole of its numerous faults. But the prolonged involuntary
residence in the country that might have resultod from this detailecl
mapping would have been so inconvenient to both of us that we
thought it advisable to forbear. A more precise survey must be
left to an Italian geologist, until such a time as the nations of the
Continent shall beat their bayonets into hammers ; the numerous
forts in the district will then afford superior accommodation to any
that can now be got in the inns.
The movements may be divided into four main sets :
(1) A thrust-plane that has carried the Trias on to the calc-schists.
(2) A series of north-and-south faults that has troughed the
Cretaceous limestones into the dolomites.
(3) 8ome east-and-west faults, to one of which the Col de
Chaberton is due.
(4) A fold that has inverted the calc-schists on the eastern slope,
and there caused an infold of the Trias.
The accompanying map and the section (fig. 3, p. 310) illustrate
the general arrangement of these movements, but the exact order of
Digitized by Google
310
THE GEOLOGY OP MOJiTE CJIABERTOS.
[Aug. 1894,
their succession is doubtful. Numerous minor faults that do not
affect the relations of the different beds to one another are omitted.
F Faults. T. .. Thrust Plane.
■
In conclusion we may summarize the results of the present paper
as follows: —
(1) In the Cottian Alps there have been three distinct series of
intrusions of basic rocks, the first pre-Triassic and \*wX-schislm
lustres, the second post-Triassic and pre-Cretaceous, the third
probably Lower Tertiary or Cretaceous.
(2) That the 1 Calcaire du Brianconnais ' consists of three distinct
rocks: — the cargntulcs and dolomites of the Trias, the limestones of
the Jurassic (which contain representatives, according to Eilian, of
the lower, middle, and upper divisions of that system), and thirdly
the shelly and coralline limestones which we call the Clos des Morts
Limestones of the Cretaceous (possibly Turonian).
(3) That, in spite of the many doubts thrown upon the presence
of Cretaceous beds in the Western Alps, representatives of such beds
are known in at least two places in the Cottians.
(4) The identification of the common Gosau coral (Calamojjhyllia
fenestrata, Reuss) in the Cottians.
Discussion.
Prof. Cole congratulated the Authors upon thoir survey of a diffi-
cult mountain-area. To him the most interesting rocks were the
schistose dykes near the summit of Monto Chaberton, showing how
much metamorphism might have taken place in the 4 pictre verdi '
generally since Triassic, and probably since Eocene times. He
believed that the metamorphism produced in the Alps by Cainozoic
earth-movementa equalled anything that had gone on in earlier
eras.
Dr. J. W. Gregory also spoke.
Mr. A. M. Davies, in reply, pointed out that the remarkable way
in which the variolitic rocks of Mont Gcnevre had escaped crushing
was one of the facts that pointed to their very recent date.
Digitized by Google
Vol. 50.]
THE GABBRO OF CARROCK FELL.
311
21. Carrock Fell: a Study in the Variation of Tqneous Rock-
Masbbs. — Part I. The Gahbro. By Alfred Harker, Esq.,
M.A., F.G.S., Fellow of St. John's College, Cambridge. (Read
May 9th, 1894.)
[Plates XVI. k XVII.]
ColfTEKTS. P"PC
1. Introduction .'ill
2. Mineralogical Characters of the Gabbro .» 316
3. Minor Textural and Mineralogical Variations 319
4. Orderly Variation from Centre to Margin 320 -
5. Discussion of the Causes of such Variation 324
6. Some Deductions from the Phenomena 329
7. Reactions between Gabbro and Enclosed Mas** of Lava 331
a Conclusion 334
Section across Currock Fell 314
1. Introduction.
During the last two years I have devoted some attention to the
igneous rocks of Carrock Fell and the hills west of that well-known
summit. Occurring in a somewhat critical situation on the border
of the English Lake District, they were examined by Mr. J. E.
Marr and myself, partly with reference to their bearing on the
general geology of the district ; but, apart from this, they offer in
themselves some features which are of sufficient interest to be worthy
of record. I have had the advantage of my colleaguo's co-operation,
more especially in the field-work, and take this opportunity of
acknowledging my indebtedness to him.
The earliest connected account of the Carrock Fell rocks was
given by the late Mr. Clifton Ward 1 in 1870. He recognized three
general types of igneous rocks in the district : —
(a) Sphcrulitic felsite of Carrock Fell and Great Lingy ;
(6) Diorite (?) of Miton Hill and Rouud Knott ;
(c) Hyperethenite of Mosedale Crags and Langdalc.
He gave a brief account of their characters in the field and under
the microscope, with chemical analyses of the first and last, and put
forward a view of their mutual relations and mode of origin. In
his opinion the several types pass into one another in the field, and
he regarded them as produced by the metamorphism of part of the
volcanic scries, on the strike of which they occur.
Br. C. 0. Trechmann,2 in 1882, pointed out that the dominant
pyroxene in the so-called hyperethenite is not hypersthene, but
diallage, and the rock would therefore be more correctly described
as a gabbro.
Mr. J. J. H. Teall,' in 1885, briefly noticed the spherulitic felsite
of Carrock Fell as a typical example of a granophyre in the sense
1 Quart. Journ. Geol. 8oc vol. uxii. (1876) pp. 16-27.
a Geol. Mag. 1882, pp. 210-212.
3 Ibid. 1886, p. 109.
Digitized by Google
312 MB. ALFRED BARKER 09 TBE 0ABBR0 [Aug. 1894,
of Rosenbusch. Later he described both this rock and the gabbro
(a quartz-bearing variety), stating that the one passes into the other
by insensible gradations.1
In 1889 Mr. T. T. Groom* pointed out the occurrence on Carrock
Fell of another type of rock, a tachylyte, in thin veins, cutting the
gabbro, but considered to be connected with it. The same writer
reasserted the existence of all transitional stages between the acid
granophyre and the basic gabbro, and this passage seems to have
been generally accepted.*
The references here given cover all the contributions of importance
dealing with the subject of this paper since the early writings of
Otlcy, Sodgwiek, and others. Ward's work is embodied in the map
of the Geological Survey.* He showed that rocks answering to the
chief types which he recognized in Carrock Fell occur to the west
as far as Koughten Gill. The sketch-map which accompanies the
present paper (PI. XVI.) differs from his as regards the boundaries
of some of these intrusions ; but in some parts, e. g. north and north-
west of Carrock Fell itself, the want of exposures makes any pre-
cision impossible. This, however, does not affect the objects of the
present study.
Carrock Foil itself is made up of an acid rock, which we may call
* granophyre,' since it usually shows very beautifully the granophyric
structure of Rosenbusch. A similar rock is found beyond the con-
cealed ground to the north-west, at Rae Crags ; also at the head of
Brandy Gill. From the latter place tho rock is probably continuous,
though never seen clearly in situ, to the exposures in the upper part
of Roughten Gill and its feeders. Intrusions of granophyre,
probably of the nature of minor offshoots, are also seen in Arm o'
Grain and Thief Gills.
The other of the two chief rocks to be distinguished, which will
be spoken of as the * gabbro,' is seen south of Carrock Fell, as far as
Mosedale village, and extends westward to Brandy Gill and Arm
o' Grain, where the exposures in the gills show it alternating with
the granophyre. A similar rock occurs in Roughten Gill and also
higher up, in Thief Gills, where, however, it is much decomposed.
The southern boundary of the main body of gabbro, from Mosedale
village to Brandy Gill, is certainly, as surmised by Ward, a faulted
one. The line between the gabbro and the granophyre runs from
the upper part of Furthergill in a W.N.W. direction to a point
about 200 yards east of Round Knott. Despite the alleged transi-
tion, which I shall discuss below, there is no difficulty in fixing
this line sharply, wherever exposures occur ; but it may be noted
that a north-and-south traverse across Furthergill crosses alterna-
tions of the two rocks, which are naturally explained as due to
offshoots of the nower one penetrating the older.
1 ' British Petrography,' 1888, p. 178.
1 Quart Journ. Geol. Soc. vol. xlr. (1889) pp. 298-30*.
3 See, for example. Zirkel, ' Lebrbuch der Petrographie,' 2nd ed. 1893, p. 781
* England and Wales, 101 K.E. (New Series, 23). This map is dated 1890,
but was not apparently issued to the public before 1893.
Digitized by Google
Vol. 50.]
OP CARROCE PELL.
,313
If the line between the main masses of gabbro and granophyre be
prolonged westward past Round Knott, it divides the gabbro which
ranges west of Iron Crajrs from the rock of Miton Hill, etc., Word's
dubious 4 dioritc.' To this title the rock has no claim, containing no
hornblende except some of secondary formation, and it will here
be named * diabase.' For reasons which will appear in the follow-
ing pages, I concur in regarding this as belonging to a separate
intrusion, distinct from the gabbro to the south ; but such a separu-
tion could not confidently be made on lithological grounds alone.
In both rocks the texture is very variable. The rock on Miton
Hill itself often Assumes the coarsely crystalline characteristic of
a gabbro, while many specimens from the crags in the gabbro-area
would, if taken apart, be desismatcd 4 diabase.' The names will bo
employed, with this explanation, to emphasize the distinctness of
the two intrusions and to mark their dominant characters. The
diabase is cut off to the north by a fault seen in the southerly branch
of Drygill, but it probably extends eastward under the much-
obscured ground north of Carrock Fell.
In addition to the above rocks, I hope to notice in a future com-
munication a very interesting one which is seen at the junction of
Brandy Gill with Grainsgill and in the adjacent hillsides. It is
only incidentally mentioned by Ward as " a very quartzo-micaceous
granite." It is, indeed, a 4 greisen,' 1 and is so named on the
Geological Survey map, where its boundary is indicated. This rock
is, as will be shown, connected with the Skiddaw granite, and has
probably no relation with the Carrock Fell intrusions.
Excluding the rock last mentioned, and taking the others as a
whole, they are intruded, as is shown on the Survey map, among
that part of the great Ordovieian volcanic scries which, is conve-
niently known as the Eycott Hill group, a group consisting essen-
tially of a succession of basic lavas. These lavas can be followed
along a curved and broken line of strike from Eycott Hill to Carrock
Fell, and they possess unique characteristics which place their
identity beyond doubt. No junction of the intrusive rocks and
these lavas is exposed along the northern line of boundary, although
the Eycott rocks are seen at Clinta Gill, etc., penetrated by small
dykes and veins of granophyre. Along the southern boundary the
gabbro is faulted against Skiddaw Slates. Mr. Ward states that
the latter are 44 much altered," an expression which seems stronger
than the appearances warrant. A certain degree of alteration may
be granted, but it is doubtful how far this is connected with the
gabbro. Tracing the Skiddaw Slates up the Caldew valley towards
the granite and greisen, we find mere induration giving place to
4 spotted' rocks, and these in turn to highly metamorphosed types
(4 mica-schists ') to which Ward's description 44 much altered " well
applies ; but near Hosedale, where the effect of the gabbro can be
tested apart from the disturbing element of the granitic intrusions,
the alteration of the slate is not great. As regards the effect of the
This rock was briefly noticed by me in ' The Naturalist* for 1889, p. 209.
Digitized by Google
Vol. 50.]
THE GABBRO OF CARROCK FELL.
315
fault, there must be a considerable downthrow to the north, but there
is reason to believe that very little of the gabbro is lost by the break.
Both granophyre and gabbro form steep cliffs to the eastward,
facing the alluvial flat of the Caldew, and they make no further
appearance in that direction. This is probably due to their natural
termination, and not to any fault. It is certain, at least, that tho
Eycott lavas come up to the intrusive masses on this side, for they
are seen in the face of the gabbro cliff and on the heights above.
The relations are not those of a simple junction of the intrusive
rock with the lavas along a definite line. As one climbs up the
cliff, e. g. at Snailshcll Crag, sometimes gabbro, sometimes lava is
seen, or the two together in intricate association, making it clear
that large portions of lava have been enclosed by the molten gabbro.
The samo relations are shown at the top of the cliff, and the Eycott
rocks occupy much of tho ground along a W.N.W. line from here to
Iron Crags, a distance of a mile or more. They are not continuous,
but occur in large detached patches embedded in the gabbro and
penetrated by countless veins of that rock. They give the idea of
having been partly buoyed up by the molten gabbro-magma, which
nevertheless welled up in every crack that was formed. A com-
parison of these phenomena with what is seen in the cliff near Snail-
shell Crag and Black Crag shows that the lavas must pass right into
the gabbro-masB in the direction named, which is that of their strike.
The remnants which are seen, embedded in gabbro, between Mose-
dale and Iron Crags are highly metamorphosed, but still easily
recognized. The well-known and beautiful porphyriric lava (No. 4
of Ward's section '), the less markedly porphyritic lavas which
succeeded it, and certain tuff-beds are clearly distinguished, and,
what is more remarkable, they seem to occur in their proper order,
and certainly follow their normal strike. It appears that the gabbro,
forced in probably along the base of the Eycott group, has not only
disturbed and lifted the lavas, but in some measure bodily engulfed
considerable stretches of them. The Eycott group in this district
has a very steep dip to N.N.E., and the mass of gabbro seems to have
a similar inclination. Whether at the time of the injection the
volcanic rocks lay more nearly horizontally is not evident from the
mapping. I have found no lavas associated with the granophyre
or the diabase. The remarkable patches of Eycott lavas enclosed in
the gabbro did not escape the notice of Mr. Ward, who noted the
occurrence of ' trap in hypersthenite ' in the neighbourhood of
Mosedale. I cannot, however, endorse his statement that the one
rock passes into the other ; the junction of the two is always of such
a nature that both rocks can be clearly exhibited in one microscopical
slice. The supposed transition was one of the grounds on which he
based his suggestion of a metamorphic origin for the gabbro and its
associated rocks.
The geological relations of the diabase need not be discussed at
this point. I shall show reasons for believing that its intrusion
1 Monthly Microsc. Journ. rol. x? ii. (1877) p. 341.
Digitized by Google
316 MR. AXFRKD IIARKER 05 THE GABBRO [Aug. 1894,
followed that of the granophyre, while that of the gabbro preceded
the acid intrusion. It may be remarked that numerous dyke* or
veins of granophyre similar to the rock of Carrock Fell occur in the
gabbro to the south, but I have not found any of these in the area
mapped as diabase. It can scarcely be doubted, however, that the
three rocks belong to the same general period of igneous activity,
and with them we may include in this statement the numerous
basic dykes and veins, of which Mr. Groom's rock is one. These
dykes were injected after all the larger igneous masses, for they are
found cutting gabbro, granophyre, and diabase alike. The geolo-
gical age of this complex of igneous rocks is a question which may
be deferred for the present.
•
The greisen of Grainsgill is probably quite distinct from the pre-
ceding rocks. It must be referred, with the more normal type of
the Skiddaw granite, to a late phase of the great post-Silurian
disturbances. It is intrusive in Skiddaw Slates, and produces in
them an extraordinary degree of mctamorphism.
In the present communication the gabbro alone will be treated in
'\ detail, the granophyre, the dykes of Carrock Fell, and thfi^gTfi?en of
I (xrainsgill being reserved for further treatment.
2. MlNERALOGICAL CHARACTERS OF THE GABBRO.
Before describing tho remarkable variations of the gabbro in
different localities it will be convenient to mention the minerals
which compose the rocks. A triclinic felspar and a monoclinic
pyroxene are essential to all the varieties, though their relative
proportions may vary considerably. Quartz and iron ores become
prominent constituents in the more acid and the more basic types
respectively. Besides these, there are accessor}' and exceptional
minerals and those of secondary- origin.
The felspar occurs for the most part in isomorphic crystals,
which, in fresh specimens, are quite clear. They always show albite-
lamellation, and usually Carlsbad twinning in addition, while
pericline-lamella) occasionally come in somewhat capriciously in
portions of the crystals. The albite-twinning is sometimes
inconstant or interrupted, but there is nothing to prove decisively
that it is in general of secondary origin, although secondary lamella-
tions, both albite and pericline, are found locally ; see PI. XVII.
fig. 2. Sections perpendicular to the lamella* give extinction-angles
up to about 32°, indicating a basic variety of labradorite. The specific
gravity is a little under 2-69. It is a point of some theoretical
importance that the same variety of felspar is found in specimens
of the gabbro differing widely in chemical composition. Only in
some of the most highly basic rocks does the felspar sometimes show
larger extinction-angles, indicating an approach to anorthite. On
the other hand, in some of the more acid quartz-bearing rocks the
border of a crystal gives a very slightly lower extinction-angle
than the main portion, indicating that the outer layers are a
Digitized by Google
Vol. 50.]
OF CARROCK FELL.
317
little more acid. This zonary structure seems, among plutonic
rocks, to be specially characteristic of those which, without being
true acid rocks, have developed free silica as the last stage of con-
solidation. Rosenbusch has remarked the general absence of
zonary structure in the felspars of ordinary gabbros.
The felspar ia, as n rule, though not invariably, of earlier
crystallisation than the pyroxene, and thus, while the latter mineral
never builds very characteristic ophitic plates, the structure of the
rock approaches that of a diabase. In view, however, of its coarse
texture and of the peculiarities of the pyroxenic constituent, I have
preferred to retain the name ' gabbro ' used by other writers.
The dominant pyroxene, as remarked by Dr. Trechmann, is
certainly a monoclinic one. It rarely shows any crystal boundaries,
but occurs in allotriomorphic plates and wedges. The colour is of
the light greyish-brown tone so frequent in diallage and salite, and
there is no sensiblo pleochroism. Besides the well-marked prismatic
cleavage, there are occasional indications of others parallel to the
orthopinacoid and clinopinacoid. Simple twinning on the usual
law, parallel to the orthopinacoid, is not infrequent, but this rarely
gives rise to repeated lamellation. The most conspicuous feature of
the mineral is a very delicate lamellation parallel to the basal plane,
often marked by a certain amount of * schillerization.' In a clino-
pinacoidal section the structure makes an angle of about 75° with
the cleavage-traces, and if the crystal be also twinned on the usual
law a very characteristic 4 herring-bone ' appearance results. (See
PL XVII. fig. 1.) This has been figured by Mr. Teall' from the
Whin Sill, a rock having several special features in common with the
Oarrock Fell gabbros. The characters of our pyroxene thus connect
it with salite rather than with diallage ; but, as the analyses of the
rocks show that the mineral is rich in alumina, I shall speak of it as
augite.
The most usual secondary alteration of the augite is that which
results in a rather fibrous hornblende of a pale yellowish-green
tint. The change begins at the margin of a crystal, and spreads to
the interior, the augite and hornblende always having the usual
crystallographic relation to one another. The completed pseudo-
morph still shows the orthopinacoidal twinning and the basal
striation with its incipient schiller-structure. Small patches of
brown hornblende in the interior of the fresh pyroxene seem to
represent an original intergrowth, but these are of quite exceptional
occurrence. Brown biotite, apparently a highly ferriferous variety
comparable with haughtonite, is a frequent accessory constituent of
the gabbro, but seems to occur only in special circumstances, which
will be noticed below.
Although the original identification of hyperethene seems to have
been erroneous, it is probable that a subordinate rhombic pyroxene
was originally present in parts of the gabbro. Such is the most
likely interpretation of certain pale green, fibrous pseudomorphs seen
1 Quart. Journ. Geol. Soc. toI. xl. (1884) p. 047, pL xxix. fig. 2,
Q. J. G. S. No. 199. z
Digitized by Google
318
MB. ALFRED HARKER ON THE GABHRO
[Aug. 1894,
in some slides. These occur more plentifully in some intrusions
near Haweswater, such as that which forms Walla Crag. Of olivine
I have found no certain trace, even in the most highly basic variety
of the gabbro. This mineral seems to be unknown in the Lake
District, except in a few minor intrusions such as that of Little
Knott.
The presence of quartz in the Carrock Fell gabbro has long been
known. It occurs sometimes in interstitial grains, but more
frequently as a constituent of micropegmatite filling the interspaees
between the augite and felspar-crystals. The intergrown felspar is
probably in part orthoclase, the analysis showing a certain amount
of potash in the rocks. The micropegmatite is a prominent con-
stituent in the most acid gabbro, and is tolerably plentiful in many
examples in which the silica-percentage must be quite low, failing
completely only in the very basic varieties. (See PI. XVII. fig. 3.)
Apatite, in rather stout prisms, is capriciously distributed. In
many slides it is wanting, but it occurs in both acid and basic
varieties of the gabbro, and in the latter sometimes rather abun-
dantly. Grains of sphene are seen in some slides, but their form
and their association with tho iron ores are such as to suggest a
secondary origin for tho mineral.
Opaque iron-ores are very sparingly present in the most acid
variety of the rock, but become increasingly abundant in the more
basic examples, and in some form a very important part of the mass.
In one case nearly 25 per cent, of the finely powdered rock was
extracted by a horseshoe magnet. These rocks, very rich in iron
ores, strongly attract the magnetic needle, but they show no evident
polarity and do not orient themselves when freely suspended. The
iron ores are in the main among the earliest products of crystalliza-
tion in the gabbro, but they do not, as a rule, show any perfection
of crystal outline. Viewed in reflected light some of the crystal-
grains show a black or bluish-black colour, while others have a tinge
of grey. The former only are attacked by cold hydrochloric acid.
It appears, therefore, that we have both magnetite and ilmenito
present, and the chemical analyses given below confirm this con-
clusion. In somo placos a crystal-grain consists partly of one, partly
of the other mineral, with crystal-faces common to "tho two and a
dividing line like a twin-lino parallel to a crystal-boundary. (See
PI. XVII. fig. 5.) This is an arrangement which does not seem to
be common in other rocks. Further, there are not wanting here
indications of a more minute intergrowth of the two iron-ore
minerals, and tho colour of some grains leaves doubt whether they
should be referred to magnetite or ilmenito. It is worthy of notice,
too, that apparently almost the whole of the iron ore in the rock
is magnetic More precise knowledge concerning * titaniferous
magnetite ' and 4 titanomagnetito ' seems desirable.
Pyrites is only locally present in the very basic gabbros (Arm o'
Grain, etc.).
Vol. 50.]
OF C.VRROCK FELL.
319
3. Miwob Textubal and Minera logical Variations.
The remarkable differences, apparent to tho most casual observer,
among specimens collected from the Carrock Fell gabbro area are
due to the coexistence of different kinds of variation, which must be
considered separately. I shall distinguish : —
(i) Minor variations in texture, and sometimes in mineralogical
constitution, usually on a small scale, following certain
directions of banding, or without any evident arrangement ;
(ii) Wide variations in chemical composition, and consequently
in minoralogical constitution, having a definite relation to
the form of the intrusive mass as a whole ;
(iii) Strictly local modifications, forming part of a reciprocal
metamorphism between (a) gabbro and enclosed masses of
lava, or (o) gabbro and granophyre.
These will not all be discussed at equal length. The first and
second are jointly answerable for tho great dissimilarity between
specimens collected from different spots, and of these the second is
of greater interest.
I have already alluded to the variability in texture of the gabbro.
As seen in the field, the change from coarse to fine grain is often
rather abrupt. Sometimes the two are associated in a quite irregular
manner, or patches of coarser rock occur embedded in finer. Such
contrasts are seen not only on a small scale, but also between
adjacent portions of gabbro, perhaps 100 yards across. In other
places rocks of different textures are associated in alternating
thin layers, simulating stratification, and slight differences in
durability produce a fluted aspect on a weathered face. Ward
appealed to this peculiarity in support of his theory that the gabbro
represents metamorphosed volcanic rocks, but such an idea is, for
many reasons, quite untenable. The phenomenon, indeed, is a very
common one, and must be familiar to most geologists who have
studied gabbros or other basic rocks.1 It presents a rather
perplexing problem, and suggests that some factor not yet fully
appreciated has had some determining influence on the crystalliza-
tion of such rocks. The banded structure of rhyolites, where
crystalline or spherulitic layers alternate with glassy, has been
explained by Iddings 3 as depending upon the different proportions
of water contained in different parte of the magma, which were
drawn out in the direction of flow, but such an explanation could
havo no application in the present case. I shall give evidence to
prove that the gabbro-magma had very little viscosity when it was
intruded, and that diffusion was able to operate through it after the
intrusion, so that the banded structure can scarcely be taken to
1 For remarks on this point, see O. H. Williams on the gabbros of Mary-
land, Bull. 28 TJ.8. Geol. Surv. vol. iv. (1886) pp. 25, 26, and A. O. Lawson on
the anorthosites and gabbros of Canada, Neuee Jahrb. Beil. Bd. viii. (1893)
pp. 448 el seqq. [See also the paper by Sir A. Geikie and Mr. Teall, which
is to be published in the present volume, where additional references are given.]
2 Amer. Journ. Sci. ser. 3, vol. xxxiii. (1887) pp. 43-46.
Digitized by Google
320
MB. ALFBED HAUKER ON THE GABBRO
[Aug. 1894,
indicate lines of flow. This structure seems to be quite independent
of the more general variation in the gabbro-mass as a whole, which
I shall describe below. At several localities the banding was
observed to dip steeply to N.N.E., which agrees with what seems
from other evidence to be the lie of the intrusion as a whole. Near
Hound Knott, however, there are lower and undulating dips, often
southerly. In most parts of the gabbro no banding is observable.
The finer-textured portions of the gabbro have in the field a
generally darker look than the coarser parts, which seem more
folspathic. This — a common observation in such rocks — is perhaps
in part illusory. There are, however, considerable local variations
in the mineralogies! composition of the gabbro, which are possibly
connected with the variations in texture. Thus, at a few spots the
rock is very ricb in augite, the lustrous surfaces of that mineral
appearing in a hand-specimen to make up by far the greater part of
the whole. At no great distance this variety may be found to give
place to one in which felspar and magnetite are richly represented.
Gabbros are well known to be peculiarly liable to such variability,
which does not necessarily import any very great difference in
chemical composition between the several varieties. The felspar
and augite probably do not differ much in silica-percentage, while
the iron which goes into the pyroxene in one case goes into the
magnetite in the other, the chief differences being probably in the
alumina and soda. However this may bo, the essential differences
which these irregular mineralogies! variations denote are certainly
far less than those to be discussed next, which have a definite
arrangement and an important significance. An account of these
wider aud more general variations will show conclusively that the
gabbro represents a single intrusion of igneous magma, which was
all thoroughly fluid at one time ; so that the abrupt local changes
and banded structure cannot be explained as the result* of successive
interlacing injections.
4. Orderly Variation from Centre to Margin.
Apart, then, from minor local variations, we must remark that
specimens of the gabbro from different localities show wide
differences both chemically and in the relative proportions of their
minerals ; and a study of the rocks in the field soon shows that the
more acid varieties occur in the central part of the mass, the more
basic near tho edge. Two chemical analyses from different localities
are given below : besides these I have had several silica- percentages
kindly determined for me by Messrs. W. A. Brend and E. H. Cun-
ningham-Craig.1 The highest silica-percentage is 59-46 for a
rock taken near White Crags ; the lowest is 32*50 for the northern
margin of the mass as exposed in the upper part of Furthcrgill Sikc.
Tho other figures obtained accord very fairly with the localities of
1 The determinations were made by Messrs. Brend and Cunningbam-Oraig
in the laboratory of Sidney Sussex College, Cambridge. Since writing the above,
I have roceiv ed the results of others made by Boyd, Pry, Ghinnell,
Gutbrie, King, and Peatfield, at the Yorkshire College, Leeds : these I owe to
the kindness of Dr. J. B. Cohen. The two sets of figures are distinguished
Digitized by Google
Vol. 50.]
OP CAHROCK FELL.
321
the specimens, on the law that the gabhro becomes more basio
from centre to margin. The mineralogical constitution of the
rocks varies accordingly. The more acid rocks, in the central
part of the area, have plenty of mioropegmatite and scarcely any
iron ore, while in the moro basio rocks of the margin quarts;: is
wanting and iron ores are very abundant, amounting in the extreme
case to nearly one-quarter of the whole rock.
A very little examination of the rocks in the field is enough to
convince the observer that the relatively acid and the extremely
basic varieties of gabbro represent modifications of one original
magma; that these extremes graduate imperceptibly into one
another through intermediate varieties ; and that all the varieties
are arranged with striking regularity in successive zones corre-
sponding in general form to the boundary of the whole mass. In
view, however, of the great difference between the extreme types
(the silica-percentage diminishing by 27 in 400 yards) and of the
important deductions to be drawn from the phenomona, it is desirable
to present the evidence of the continuity of the whole mass in some
precise form. To obtain a large number of chemical analyses was
impracticable, and I have accordingly availed myself of the density
of the rocks as a rough tost of their relative basicity, or, more
particularly, of their relative richness in the denser minerals. This
of course agrees in a general sense with the silica-percentages, the
less acid rocks being the heavier; but, judging from such data as
we have, the agreement does not always hold very precisely. The
figures for specific gravity are found to show a much more regular
distribution than those for silica-percentage. The reason for this
is easily seen : the most important respect in which the several
specimens differ is in their content of iron oxides, and the best test
Wow hv the letters S and L, respectively. I give here those which relate to
the gabhro, and with them the figures from Mr. Barrow's two analyses and
from that by Mr. J. Hughes mentioned in Ward's paper.
(i) White Crags :
Silica 5^46 (S) ; sp. gr. 2 804.
(ii) White Crags (the locality may be some distance from the preceding) :
Silica 59 856 (Hughes),
(iii) 350 yds. S. of White Crags, 120 yds. W.N.W. of sheepfold :
8ilica 577 (S) ; sp. gr. 2 877.
(it) By road-side, about 150 yds. N.N.W. of Chapel Stone:
Silica 53 50 (Barrow) ; sp. gr. 2800.
(t) Same locality :
Silica 50-5 (L).
(ti) 600 yds. S.W. by S. of White Crags, 200 yds. E.S.H. of sheepfold :
Silica 50-22 (8) ; sp. gr. 2 939.
(rii) 120 yds. N. of summit of White Crags .
Silica 47 11 (S) ; sp.gr. 2 848.
(viii) Top of cliff above Mosedale. southern edge of gabbro :
Silica 44- 14 (S) ; sp. gr. 3- 103.
(ix) Gill § mile N.W. of Swiceside, southern edge of gabbro :
Silica 43-4 (L) ; sp. gr. 2 952.
(x) Lower part of Furthergill, northern edge of gabbro :
Silica 33-4 (L) ; sp. gr. 3 200.
(xi) Upper part of Furthergill, northern edge of gabbro :
Silica 32 50 (Barrow) ; sp. gr. 3 265.
Digitized by Google
822
MR . ALFRED UAKKKK ON THE OABDRO
[Aug. 1894,
of this, short of actual estimation of the iron, is the density of the
rocks.
The specific gravities have been determined by the hydrostatic
balance on specimens usually of more than 50 grams, and so large
enough to eliminate small variations : the figures are all reduced
to 4° C. The mean specific gravity of specimens from forty-two
different localities in the gabbro area is 2-953, and the range of
variation is about 20 per cent, of this mean, the extreme figures
found being 2 679 and 3*265.
If we take a traverse from north to south across the gabbro, we
find the specific gravity to decrease steadily until the central zone
is passed, and then to increase steadily to the other border of the
intrusion. Below are the figures for three parallel traverses across
the eastern portion of the area, where exposures are most frequent.
Each hiatus represents a place where the rocks are concealed : —
3-222
3-265
3-200
2-848
2-804
2-850
2-933
2-778
2-822
2-800
2-844
2-890
2-872
2-877
2-939
2-922
3110
3-103
It will be seen that, without exception, the gabbro grows denser
from centre to margin in both directions. The full significance of
the figures, however, is seen only when they are laid down on a
map. With a sufficiently large number of observations, it would
be possible to connect points corresponding to equal specific gravities
by lines like the contour-lines round a hill or the isobars round a
cyclonic centre. I have not attempted to go so far as this, but I
consider that the figures given are sufficient to establish the continuity
of the whole mass and the distribution of the several types in
roughly concentric zones becoming denser from the centre to the
margin of the area. The accompanying map (PI. XVI.) shows the
approximate course of lines corresponding to specific gravities 2-85
and 2-95. These arbitrarily chosen limits divide the gabbro area
into three parts :
(i) A central portion of specific gravity less than 2-85 : here the
rocks are relatively acid, and usually contain rather abundant
quartz ;
(ii) An intermediate zone of specific gravity 2-85 to 2-95 : con-
sisting of more normal gabbro, in which quartz is at most
an accessory constituent ;
(iii) A marginal zone of specific gravity above 2*95, and in the
limit very much higher: the conspicuous feature here is
the great abundance of the iron ores.
Without entering into further detail, it will be taken as proved
that the various types are only parts of a single body of rock, which
becomes progressively richer in iron oxides (and, as we shall seer
in certain other constituents) from centre to margin, and that this
change is most rapid as we approach the actual boundary of the
Digitized by Google
Vol 50.] OF CAREOCK FELL. 323
mass. In other words, there has been, from whatever cause, a
concentration of the iron oxides and certain other constituents in
the marginal portion of the mass.
Phenomena indicating a concentration of this kind have been
recorded in numerous instances from different parts of the world.
Prof. Vogt1 has recently reviewed the literature of the subject
and critically examined all the leading facte ; so that it is not
necessary here to enter upon so wide a field. The phenomena are
characteristically found in basic and ultrabasic rocks, and in extreme
cases havo given rise to almost pure aggregates of iron ore of un-
doubtedly eruptive origin. Vogt distinguishes especiall}* an ' oxidic '
type of concentration, characterized by the secretion of titaniferous
iron-oxides, and a ■ sulphidic ' type, characterized by nickeliferous
iron-sulphides. At Carrock Fell we evidently have to do with the
former type. According to Vogt the titaniferous iron-oxides tend
to aggregate by preference in the central part of an eruptive mass,
while the nickeliferous iron-sulphides concentrate in the marginal
part. As regards tho former, this generalization seems to go rather
beyond tho facts, and the case that I am describing is emphatically
opposed to it. In some of the cases which Vogt notices of aggre-
gates of iron ores in the heart of an eruptive mass, the aggregates-
evidently are abruptly bounded, and their secretion from the magma
must have taken place before the intrusion, so that the original
relations are lost. Where a perfectly graduated transition indicates
a differentiation of the intruded magma in «7u, the enrichment in
iron oxides, etc, seems to be typically a marginal phenomenon.
I now proceed to examine more closely the variations in the
chemical composition of the gabbro. My friend, Mr. G. Barrow, of
the Geological Survey of Scotland, has had the kindness to make a
complete analysis of one selected specimen and a partial analysis of
another. The formor is an example of the quartz-bearing gabbro,
though not actually the most acid rock found. The latter is the
densest and most basic specimen obtained, having an extraordinarily
large proportion of iron ores.
8iOa 53 50 32 53
TiO. 0-45 5-30
ALO, 22 20
FeaO, 3-BO 844
FeO 2-64 1710
MnO 035
MgO 200 7-92
OaO 945
NajO 4 26
KaO Ofil
Ignition 1*50
10059
Specific grarity ... 2800 3265
I. Quartx-gabbro, by roadside, 150 yard* N.N.W. of Chapel Stone. (The
lime is probably a little too high.)
of Kurt!
II. Iron-ore gabbro, upper part of Kurthergill Sike.
1 Zeilaohr. fur prakt. GeoL voL i. (1893) pp. 4-11, 125-143, 257-284.
Digitized by Google
324
MR. ALFRED MARKER ON XHK GABBRO [Aug. 1 894,
One point brought out by these analyses is that the augite, and
the uralitic hornblende derived from it, must be rich in alumina.
Another point of interest is that the iron ore is in a high degree
titaniferous. If from the second analysis we calculate the iron ores
as magnetite and ilmenite, the percentages of these are found to be
12*24 and 9*93 respectively, the two together thus constituting
22-17 per cent, of the whole rock.
Looking simply at the bulk-analyses, we observe that while
analysis II. shows more than four times as much iron oxides as I.,
and nearly four times as much magnesia, it shows about twelve
times as much titanic acid. In other words, regarding the second
rock as a basic modification of the first, the titanic acid is much
more strongly concentrated in the basic factis than the iron-oxides
are. This is in agreement with what is recorded in other districts,
such as those of Ekersund and Taberg. Vogt 1 remarks as character-
istic of this type of modification ('oxidic' secretion of iron ores) that
there is never leas titanic acid than that corresponding to the rela-
tion Ti : Fe = 1 : 10, and often considerably more. In our rock
the ratio is 1 : 5-3. As regards the other constituent*, which were
roughly estimated for the second rock, though exact figures are not
given, analysis II., as compared with I., shows, in addition to the
great falling off in silica, a very considerable reduction in lime, and
a certain diminution in the percentage of soda, while the potash
disappears almost entirely. Phosphoric acid has not been estimated,
but the microscope shows that apatite, which is scarcely to be
found in most specimens of the more acid varieties of the gabbro,
becomes locally abundant in the highly basic marginal rocks. In
all these particulars, the variation observed here resembles that
recorded by Vogt and others in other parts of the world.
The Carrock Fell gabbro illustrates, then, a clearly characterized
type of continuous variation in a single intrusive mass of basic
rock, the variation being related in a simple manner to the boundary
of the mass. It cannot be doubted that all the varieties have been
derived by the differentiation of a single magma after its intrusion,
and that such differentiation consisted in a concentration of what
we may call the more basic constituents of the magma in the
marginal parts. The phenomena thus afford an opportunity of
bringing to the test some of the ideas that have been put forward
with reference to the probable causes of differentiation in rock-
magmas, and this I shall briefly attempt to do.
5. Discussion of the Causes of such Variation.
Several possible causes of differentiation have been suggested,
and one or other of them may have been the chief cause in particular
instances. In the present case the circumstances enable us to
eliminate at once some of these suggestions. It may be remarked
first that the concentration of the basic constituents is found along
both the northern and the southern margin of the mass. These
* Zeitachr. for prakt OeoL roL i. (1893) p. 10.
Digitized by Google
Vol. 50.J
OF CAKKOCK. FELL.
325
probably represent the upper and lower sides of the intrusion as
originally consolidated, but, whether this be so or not, the bilateral
symmetry proves that gravity has not been the determining factor.
This disposes, for the case under consideration, of the idea of a
fluid magma becoming richer — in its lower strata — in the denser
constituents ; snd also of the notion of the earlier formed crystals of
iron ores, etc., sinking in the still fluid magma. If these processes
have operated at all, they have produced effects only quite sub-
ordinate to the general differentiation observed. Again, Vogt has
suggested that any inequality in the distribution of iron compounds
in a molten magma, once sot up, might be augmented by magnetic
attraction. This idea is propounded apparently with reference to a
central rather than a marginal concentration of iron ores in a
magma, and moreover it could not account for the observed con-
centration of other constituents, such as phosphoric acid. In view
of the fact that natural magnetite loses its magnetic property com-
pletely -when heated to 557° C, it does not seem likely that magnetic
attractions can play any part in the equilibrium of a molten rock-
magma, and I shall accordingly discard this suggestion.
The only possible causes of differentiation that remain in the
case under consideration are those which depend on the difference
of temperature between the central and marginal parts of the magma
while still fluid or partly fluid ; and the concentration of the iron,
etc., towards what were the cooling surfaces of the mass seems to
point directly to the influence of this factor. In what way this
influence took effect is a question requiring some discussion.
Most writers who have speculated on the mode of origin of a
heterogeneous rock-complex by differentiation of a magma originally
of uniform composition, have based their conception of the nature
of the magma on its analogy with an ordinary saline solution.
Lagorio 1 apparently considers that one or more definite silicate-
compounds (KaO 2SiOa, etc.), which he terms * NormalgUu* act
as solvent for all the other constituents. It is not easy to reconcile
this view with the existence of a very fairly constant order of
crystallization for the several minerals. For instance, however
little phosphoric acid and however much of the iron oxides a
magma contains, apatite seems to crystallize out invariably before
magnetite or iron-bearing silicates ; and, in general, the order of
crystallization depends little, if at all, upon the relative amounts of
the several constituents contained in the magma. As an alternative
to Lagorio's idea of a single general solvent, we might perhaps
imagine that a constituent on the point of crystallizing out is then
the dissolved substance, the remaining fluid magma as a whole being
the solvent. Some such idea seems to be intended by some authors
who have not very clearly defined their view of an igneous rock-
magma as a solution.
Now, it follows from the theory of osmotic pressure that if
different parts of a simple saline solution be at different temperatures,
the concentration must also vary, and equilibrium will be established
» Tscherm. Min. u. Petr. Mitth. vol. viii. (1887) pp. 607, 608.
Digitized by Google
32(J
MB. ALFBED IiARKEK OX THE GABBBO
[Aug. 1894,
only when the concentration at every point is inversely propor-
tional to the absolute temperature. Soret has demonstrated ex-
perimentally the greater concentration of the salt in the cooler
part of the solution. This law, known as ' Soret's principle/ has
been applied by Lagorio, Teall, Brogger, Vogt, Iddings, and others,
to the case of an igneous rock-magma regarded as a solution. In
particular, the relative richness of the marginal parts of an intrusive
mass in the more basic minerals has been explained as due to the
concentration of the less soluble constituents of the magma, while
still fluid, in the cooler region.
On this point one or two remarks may be made. In the first
place, the idea cannot be entertained at all in connexion with
Lagorio's theory of a single general solvent. As Backstrdm 1 has
pointed out, differences of temperature could not, on that hypothesis,
alter tho relative concentration of different dissolved constituents.
We are therefore driven to some less precise and more complex
view of the nature of the 4 solution ' in a rock-magma. Supposing, •
however, that something analogous to Boret's principle still holds,
we may enquire whether this is adequate to explain the degree of
concentration actually observed in the case of the Carrock Fell
gabbro. The precise law arrived at by van't Hoff, identical with
the law for gases, states that, in the condition of equilibrium, the
concentration of the dissolved substance varies inversely as the
absolute temperature. Now, in our case, the amount of iron ores in
the rocks at the margin of the mass is at least twenty-five times
the amount in the rocks at the centre; but it is manifestly
impossible that the absolute temperature of the magma at its centre
could ever be twenty-five times, or even five times, that at its
margin. The explanation is clearly insufficient to account for the
facts.2
It must be understood that I speak here of differentiation effected
in situ in a magma, which may fairly be assumed to have been of
uniform composition when intruded into its surroundings. We are
not, in this case, concerned with successive differentiations of
magmas and partial magmas amidst new surroundings, as conceived
by Iddings, or as described by Brogger. On any solution-hypothesis
of rock-magmas, Soret'B principle does not afford an explanation of
the variations observed in the Carrock Fell gabbro. Further, I
question how far that principle, which holds good for dilute solutions,
can throw light on the physics of a rock-magma near the point of
crystallization, which must be compared with a nearly saturated
solution.
The phenomena of differentiation described by Prof. Brogger
in the eruptive rocks of the Christiania basin, and especially in
those of the Gran district,8 differ in a fundamental respect from
1 Journ. of Geol. yoI. i. (1893) p. 774. The author, however, does not
limit bis criticism, as is here done, to this particular view of the solvent medium.
3 This argument has been advanced by me in a brief note : Geol. Mag. 1803,
pp. 546, 647.
3 Quart Journ. GeoL Soe. vol. 1. (1894) pp. 16-37.
Digitized by GoogI
Vol 50.]
OK CAliROCK 1'KLL.
327
those described above at Carrock Fell. Brogger points out that
in his area rocks genetically connected may differ widely in
mineralogical as well as in chemical composition. Thus, in his
olivine-gabbro-diabase, the ferromagnesian minerals are pyroxene,
olivine, and biotite ; in the camptonite, which is an offshoot of it,
brown hornblende largely predominates. He justly concludes that
differentiation has " taken place in a liquid magma, even before
crystallization of any importance had begun." In the Carrock Fell
gabbro the case is quite different. Here the different varieties of
the rock consist invariably of the same minerals, only in different
relative amounts.1 I have already remarked that the felspar is of
the same variety in almost the whole of the rocks examined. If
the differentiation of the magma had been completed prior to any
crystallization, we should expect different parts of the magma to
have given birth to different varieties of felspar. The complete
want of olivine, even in the ultrabasio varieties of the rock, is
another fact that would be difficult to explain on the hypothesis
that the magma was differentiated first and then crystallized ; and
indeed such a sequonce of events seems to be quite inconsistent
with the phenomena that I have described. On the other hand, to
suppose that the differentiation was brought about by a migration
of minerals already crystallized out would raise obvious difficulties.
No cause can be imagined to produce such a movement of crystals
to the margin of the reservoir. The only alternative is to suppose
that the differentiation took place by diffusion in a fluid magma,
but not as a process distinct from and quite anterior to crystallization.
It was, as I believe, effected in a quasi-saturated magma concurrently
with the crystallization of the earlier-formed minerals.
The remarks just made apply, as stated, to the particular case
under discussion, but it seems probable that many of the examples
of differentiation recorded by Vogt and others will fall under the
same head. The characteristic of all is that the several constituents
are concentrated in a definite order, which is identiad with the order
in which they crystallize out from the magma (Roscnbusch's 44 order
of decreasing basicity The concentration is greatest for the
minerals belonging to the earliest stage of crystallization, viz.
apatite, ilmenitc, magnetite, etc. The minerals of tho second stage,
the ferromagnesian silicates, aro less strongly concentrated. In
such cases, when differentiation apparently " has been determined
by, and is dependent on, the laws of crystallization in a magma,"
it seems reasonable to seek the cause of differentiation in the
crystallization itself.
The conditions introduced by this simple hypothesis havo no
analogy with those of a dilute solution : and, though we may
conveniently employ the terminology of solutions in speakiug of it,
it does not follow that we need frame any precise theory of the nature
of an igneous rock- magma. Tho process of differentiation is brought
1 Quartz and orthoclase are wanting altogether in the most basic Tarieties,
but these, being the rerj latest product* of consolidation, do not enter into the
argument.
328
MR. ALFRED HARKKR ON THE GABBRO
[Aug. 1894,
at once under the perfectly general principle of the degradation of
energy. In whatever form the elements of a given mineral exist in
the fluid magma, it cannot be doubted that the crystallization of
the mineral from the magma involves in every case a very
considerable evolution of heat. Hence whatever promotes crystal-
lization in the magma will tend to the most rapid degradation of
energy. When crystallization has already begun in one region of
the magma, this result will be attained by a determination of that
constituent with which the fluid is most easily saturated to that
region of the magma which is already on the point of saturation.
The region of the magma which first becomes saturated with a
certain constituent will therefore, as crystallization proceeds, have
its saturation maintained by diffusion at the expense of the
rest of the magma. It is evident that, as a perfectly fluid magma
cools down, the point of saturation, say with apatite (or with
phosphoric acid), will be reached first in the margin of the body of
raagraa, that being the coolest region and also, if the Soret action
has already set up heterogeneity, the region of greatest concen-
tration of the substance in question in the fluid magma. Apatite
begins to crystallize out at the cooling surface of the magma, and
diffusion maintains the saturation and crystallization in this the
coolest region. Ilmenite and magnetite follow, and in turn the
ferromagnesian silicates. But there will evidently be a tendency
towards restoring temperature-equilibrium between the margin and
the interior, and, what is more important, with falling temperature
and increasing acidity tho residual magma becomes so viscous that
diffusion is more and more checked, and finally ceases. Thus the
concentration towards the cooling surface is strongest for the first-
formed minerals, and continually feebler for those which follow,
according to their order of succession.
It seems, then, that the intimate relation between the phenomena
of concentration and of crystallization, which has been remarked by
several writers, leads to a simple explanation of the concentration
of certain constituents in the marginal parts of a rock-mass ; and
from this explanation the fact that the order of concentration of
the several constituents is also the order of their crystallization
follows as a necessary corollary. Further, there is here no narrow
limitation of the possible degree of concentration, such as that
which the law of osmotic pressure imposes upon the Soret action.
There is no difficulty, for instance, in admitting that a pure
abrogate of ilmenite may segregate from a rock-magma. According
to ♦ Soret's principle/ this would imply an infinite degree of con-
centration, corresponding to absolute zero of temperature !
There is, howover, one consideration that must not be passed
over without notice. Backstrom 1 asserts that u a silicate magma
during its period of crystallization is certainly too viscous to permit
of any considerable diffusion." It does not appear on what
evidence this statement rests. The petrographical features which
most clearly point to high viscosity are connected especially with
1 Journ. of Geol. toI. i. (1893) p. 773.
Digitized by Google
<
Vol. 50.] OP CARROCK FELL. 329
the later stages of consolidation in acid lavas : while the phenomena
of differentiation are most strikingly exhibited in the earlier stages
of consolidation of basic inta|gjtYe rocks. The best experimental
results bearing on the question are those of Vogt,1 obtained from
artificial slags having the general composition of igneous rocks.
Any differences that exist between the conditions in the artificial
and the natural magmas will probably tend to lower the viscosity
in the latter, which may be expected to contain a certain amount
of water in all cases, and sometimes other fluxes (' agents minerali-
sateurs '). Vogt found viscosity to be in direct relation to acidity,
the results differing widely for extreme cases. At the same
moderate temperature-distance above their respective melting-
points, strongly basic slags flow like water, while strongly acid ones
are as stiff as tar. The « melting-point ' of a rock-magma is not
a term of precision ; but, so far as our knowledge goes, it seems
highly probable that diffusion can proceed freely during the earliest
stage of crystallization in a basic rock-magma, being, however,
checked more and more as tho temperature falls.
6. Some Deductions from the Phenomena.
I have dealt rather fully with the gradual variation of the gabbro
from centre to margin, because the results, if they are considered to
be established, bear upon theoretical questions which have lately
attracted much attention. But these results also have very
direct consequences for the particular area under discussion, leading
to certain definite conclusions as to the geological relations of this
gabbro intrusion, and enabling us to discard confidently certain
suggestions that have been made under this head. Similar
reasonings will be applicable to other masses of igneous rocks
showing a like type of differentiation. The several points arc
sufficiently obvious to be treated summarily.
Firstly, then, the gabbro is a true igneous rock. The wholo
body of it was at one time fluid enough to admit of the freest
movement among its parts, and that too wJtile all the surrounding
rocks were cool. This consideration, we think, is enough to dispose
of the theory of Mr. Ward,3 that the gabbro has been produced by
extreme metaraorphism of the volcanic rocks. Chemical and other
facts equally militate against such a hypothesis.
Next, we see that the gabbro mass does not represent any
portion of a duct of a volcano, but is an intrusion of laccolitic type.
The magma was injected among cool rocks, and there consolidated.
Had there been any prolonged flow of molten matter, the sur-
rounding rocks must have become heated, and the mass that finally
1 Zeitachr. fiir prakt. Geol. vol. i. (1893) p. 275.
3 Ward quote* from Sedgwick a passage in the same general sense, though
offered merely 'a* a conjecture' (third Letter to Wordsworth, 1842).
J. G. Marshall maintained the Currock Fell rocks, with all the chief igneous
masses of the Lake District, to be of metamorphic origin (Report Brit. Assoc.
1858, Trans. Sect. p. 84.)
Digitized by Google
330 ME. ALFRED HABERE Off THE OABfiRO [Aug. 1 894,
plugged the channel would havo consolidated without the conditions
necessary for the kind of differentiation described. Indeed we may
take it as a general rule that the duct of a volcano is characterized by
very considerable everte, but an absence of inverse metamorphism.1
In the present case the form of the intrusive body and the
manner in which the volcanic rocks follow their strike undisturbed
through the heart of the gabbro also indicate unmistakably the
nature of the intrusion.
AgaiD, the alleged passage from the gabbro to the granophyre is
seen to havo no real existence, at least so far as concerns the
phenomena in the former rock. That modification of the gabbro
which in some petrographical features approaches the acid rock,
forms the heart of the gabbro mass, while that in actual contact with
the granophyre is of a highly basic variety. I propose to consider
the question again from the side of the granophyre, but it is quite
clear that the two rocks represent two distinct and successive
intrusions. This is, of course, quite consistent with the possibility
of the two magmas having been derived from different portions of
one deep-seated reservoir.
Finally, I cannot accept Prof. Sollas's suggestion a that the
micropegmatite of the quartz-gabbro is due to an injection of
solid gabbro by the granophyre magma. There are certainly
veins of granophyre penetrating the gabbro, and locally numerous,
but these are never on the microscopic scale described by
Prof. Sollas at Barnavarve, and the orderly disposition of the
various types of gabbro in the Carrock Fell intrusion would be
unintelligible on the injection hypothesis. I shall have to speak
later of the possibility of intermediate rocks originating by the
admixture of acid with basic, in a somewhat different manner,
but I do not believe that the idea is capable of any very wide
extension.
These conclusions seem to follow fairly from the phenomena of
differentiation- described, though they can be fortified by other
considerations. I wish to point out, however, that these phenomena
may sometimes lead to conclusions which could not otherwise be
reached ; so that a careful survey of an igneous mass by chemical
tests, or simply by specific gravities, may give definite information
regarding the field-geology of the district. Thus, tho separation of
the areas which we have distinguished as gabbro and diabase comes
out distinctly in this way, the zone of basic rock which bounds the
gabbro area on the side of the granophyre being evidently prolonged
westward by Round Knott. When thus divided, the relative age
of the two rocks can be decided. It might, of course, bo conjectured
plausibly that, since veins of granophyre are abundant in the gabbro
and wanting in the diabase, the one rock is older and the other
1 These terms, due to Morlot, betides having priority, seem to be more
pointed and less clumsy than their equivalents ' exotnorphic and endomorphic,'
or 'exogenous and endogenous,' used by some German and French writers.
3 QeoL Mag. 1893, pp. 651, 652. [Subsequently elaborated in Trans. Roy.
' Acad. vol. xxx. (1894) pp. 477-512.]
Digitized by Google
Vol. 50.]
OF CA.RROCK FELL.
331
newer than the acid intrusion 1 ; but the way in which the gabbro
is differentiated affords at least as strong an argument in the same
direction. It is noteworthy that, so far as the few observations of
specific gravity go, the diabase seems to be much more uniform
than the gabbro, as if the requisite condition for differentiation,
namely, cool encasing walls, had been wanting in the case of the later
intrusion.
Again, if the basio margin may be taken as marking with
tolerable uniformity the original boundary of the gabbro mass, its
completeness or otherwise will give information with respect to
subsequent accidents which may have affected it. The presence of
a basic border on the south side of the intrusion may be taken as
indicating that very little of the gabbro is lost in consequence of
the bounding fault. On the northern boundary some irregularities
occur which suggest that portions of the basic margin of the mass
may have been carried away by the later intrusion of granophyre,
and I shall have occasion later to notice phenomena in the latter
rock which fully accord with this idea. Again, tho narrowing of
the outcrop of the more acid type of gabbro towards the east seems
to point to a termination of the intrusive mass in that direction, so
that no fault would be required to account for the non-appearance
of the gabbro on the other side of the valley alluvium. As regards
the westward termination of the intrusion, the country there is
much concealed by peat-mosses, but the thoroughly basic character
of the gabbro seen in Roughten Oill and in Brandy Gill3 may
perhaps point to a coming together of the northern and southern
boundaries of the original intrusive body, which is broken into by
considerable masses of granophyric rocks. '
7. Reactions between Gabbro and Enclosed Masses of Lava.
There remain to be briefly noticed certain special modifications of
the gabbro which are of an entirely different order from those
described above, being local or ' contact '-phenomena. As already
mentioned, some of these peculiarities arc connected with the enclosed
patches of volcanic rocks, others with tho proximity of the large
granophyre intrusion. Only the former will be treated at length in
I have stated that the masses of basic lava enveloped by the
gabbro are readily identified as members of the Eycott Hill group,
the typical locality for which is less than 3 miles distant. The
rocks are 'nevertheless very considerably metamorphosed, and the
gabbro in their immediate vicinity shows certain signs of inverse
raetamorphism. The lavas as they occur at Eycott Hill were briefly
described by Mr. Clifton Ward,' who gave chemical analyses
1 I bare found no actual exposure of the contact of granopoyre and diabase
in situ, but junction -specimens of the two rocks occur among tbe loose blocks
to the nortn of Great Lingy, and in tbese the diabase takes on a very fine-
grained texture.
3 8peciflc gravities : Roughten Gill 31 13, Brandy Oill 3-W5.
3 Monthly Microtc Journ. toL xviL (1877) pp. 239-246.
Digitized by Google
332
MB* ALFRED HA It K EH ON TIIF. UAHBllO
[Aug. 1894,
showing from 51-1 to 53*3 per cent, of silica. Prof. Bonney 1
pointed out the occurrence in these rocks of an altered rhombic
pyroxene. Mr. Teall 3 has given an account of one of the most
remarkable flows. The characteristic features are the occurrence
of large porphyritio crystals of a lime-soda felspar, frequently
rounded and having peculiar inclusions, and the abundance in the
groundmass of magnetite and pseudomorphs after hypersthene.
The metamorphosed lavas enclosed in the Carrock Fell gabbro have
a fresh aspect and a high density, the specific gravities of the
conspicuously porphyritic and the more compact types being 2*835
and 2-887, as compared with 2*754 and 2*744 at Eycott Hill. The
groundmass has become darker and more lustrous, and the large
felspars have a clearer appearance, though not otherwise altered to
the eye. Under the microscope it is seen that these felspars have
for the most part lost their conspicuous inclusions in the form of
negative crystals, but the crystals usually retain their identity, and
show their albite- and Carlsbad-twin uing unaltered. Only occa-
sionally have they been recrystallized into a new mosaic [1550] in
the fashion that we have noticed in the basic lavas bordering the
Snap granite. The serpen tinous or bastite-pseudomorphs after
hypersthene have been converted into a very pale, greenish
amphibole of rather fibrous structure. Possibly some of this
mineral may represent the original augite of the lava or its
decomposition-products, but the metamorphosed examples sometimes
contain fresh augite [1549, etc.]. The little twinned felspars of the
groundmass resemble those of the unaltered rocks, except in a greater
freshness and clearness, which could scarcely be interpreted as
conclusive evidence of recryetallization, but they sometimes appear
to fit together in the manner characteristic of metamorphosed rocks.
The magnetite seems to be on the whole in better octahedra than
in the unaltered lavas. But what points more unmistakably to
some degree of recrystallization in the groundmass is the disap-
pearance in the most altered rocks of the isotropic base.
So far I have noticed familiar, and not even extreme effects of
thermal metamorphism in basic lavas.3 There are, however, at the
actual junction of the lava with the gabbro, phenomena more
unusual, involving reciprocal modifications in the two rocks. I
have said that the line of junction can be shown in a thin slice
under the microscope, but it is often a curiously irregular line ; and
the plexus of small felspar-prisms, which constitutes a large part of
the groundmass of the lava, has been, so to speak, ' teased out '
at the edge, so that scattered prisms lie a little beyond what
1 Geol. Mag. ISSo, pp. 7G-80.
2 'British Petrography ' 1888, pp. 225-227. For a notice of the same lavas
as seen at Mclmerby, across the Eden valley, Bee Quart. Journ. Geol. Soc.
vol. xlvii. (181)1) p. 517.
3 Some of the lavas, on the southern edge of the gabbro, show a different
type of metamorphism, and especially the development of abundant red
garnet*. These phenomena, which are found in very many parte of the Lake
District, have, I beliere, no direct connexion with the gabbro intrusion, and
they will not be further referred to in this place.
Digitized by Google
Vol. 50.]
OP CAR HOCK FELL.
must be regarded as the true line of junction. These scattered
prisma of plagioclase are embedded in a perfectly clear mosaic
of moderately coarse texture, which seems to be in some
cases of quartz, in others of felspar, mostly untwinned. The
structure is thus that which G. H. Williams 1 has termed * micro-
poikilitic' The general appearance is as if the felspars had been
set free, by what was originally the isotropic base of the lava
becoming dissolved and absorbed into the gabbro-magma. The
material thus taken up is doubtless represented in part by the brown
mica which we find in the neighbouring gabbro, but the quartz
and the (probably acid) felspar of the clear mosaic are perhaps
to be referred to the same source. Mica is developed only excep-
tionally in the metamorphosed lava, and has somewhat different
characters from that in the gabbro. Its pleochroism is from a rich
brown to colourless, and there are intensely pleochroic haloes around
certain inclusions too minute for identification [1549].
Certain narrow veins, conspicuous in hand-specimens, pass from
the gabbro-junction into the lava, and contain especially idiomorphic
brown hornblende moulded by quartz [1626]. Again the micro-
poikilitic areas may take on the form of little veins extending into
the lava [1553], or these may anastomose and spread for a short
distance from the junction. Indeed, the groundmass of the lava
very near to the gabbro seems locally to be replaced by patches of
clear quartz, etc., wedged in among the porphyritic felspars, the
needles of apatite, and tho pyroxenes or their representatives [1625,
etc]. Both pyroxene and magnetite seem in some places to have
been absorbed.
It must be concluded from these phenomena that the gabbro-
magma has to some extent corroded away and incorporated in itself
the glassy base of the lava, and even in places some of its minerals,
in the immediate neighbourhood of the junction. Nevertheless all
the facts go to negativo the idea that the lava has been to any
important extent melted down by the gabbro-magma. The felspars
have not apparently been dissolved at all. Even the little prisms
remarked as occurring outside the line of junction show no rounding
or diminution in size, and since they do not occur to any
greater distance than a fraction of an inch, it seems that very little
of the rock can have been removed. The blocks of lava, and the
fragments into which they are divided by veins of gabbro, are
sharply angular.
The same inference might be drawn from an examination of the
gabbro near its junction with the lavas. The rock here, and for a
few feet, always contains brown mica, a mineral foreign to the
normal gabbro. The mica, indeed, occurs nowhere elso in the mass,
with an excoption to be noted below. At one or two spots where
the mineral was noticed no lava was actually exposed, but these
places were on the line of strike of the Eycott group as seen not far
away, and doubtless mark the position of concealed patches of lava.
1 Journ. of Geol. vol. i. (1893) p. 170.
Q. J. G. S. No. 199. 2 a
Digitized by Google
MR. ALFRED II ARK EH ON THE OADBRO
[Aug. 1894,
If it be granted that the mica in the gabbro is a phenomenon of
inverse contact-metamorphism, due to the absorption of a certain
portion of the enclosed lava by the gabbro-magma, an interesting
conclusion follows. It is clear that if such absorption had taken
place soon after the intrusion of the gabbro-magma, when that
magma was fluid enough, as we have seen, to permit free diffusion
throughout, the brown mica could not have been restricted, as it is,
to the immediate neighbourhood of the lava. The action must
therefore belong to a later stage, when the magma had attained a
considerable degree of viscosity, and must be connected with the
growing acidity of the magma in its central region due to concen-
tration of the basic constituents in the marginal parts. In point of
fact, it is in the quartz-bearing varieties of the gabbro that these
phenomena of inverse metamorphism are observed.
8. Conclusion.
The last kind of modification of the gabbro to be noticed is seen
near the northern edge of the mass, at Furthergill and westward.
On comparing the dense iron-ore gabbros along this strip with
those on the southern border of the mass, certain peculiarities are
observed which can only be referred to the proximity of the large body
of granophyre intruded at a later time, when the gabbro was solid.
Some of these peculiarities may be considered simply as
phenomena of metamorphism produced by the heat of the later
intrusion. Thus, instead of the usual uralitic alteration of the
augite, we find that mineral passing in a capricious fashion into
a compact brown hornblende, which probably indicates some
absorption of iron oxide from the ilmcnite. Granular sphene has
arisen probably from reaction between the ilmenite and the felspar
[1866]. The felspar is much broken up into secondary minerals,
among which specks of a pale amphibole are conspicuous as well
as chloritic substances. Pale fibrous amphibole sometimes forms
a fringe in crystallographic rolation with augite, but evidently
occupying the place of felspar [1525]. There are large patches
consisting essentially of matted tremolite-fibres, the origin of
which is not clear. With this may be associated a little brown
mica [1536], while small patches of this or of a deep brown horn-
blende have formed characteristically about some of the grains of
iron ore. The various changes observed, or at least some of them,
point to thermal metamorphism of the gabbro by the granophyre.
(See also PI. XVII. fig. 4, and explanation.)
The rocks showing the above features may be regarded as the
margin of the gabbro proper. They are immediately succeeded by
rocks of a very remarkable character, which form a zone running
up Furthergill and onward nearly to Round Knott, dividing the
gabbro from the granophyre. Along this zone the gabbro has
been in great part actually re-fused, and has crystallized again as a
rock of strikingly coarse texture, with large idiomorphic felspars
and large well-built crystals of hornblende. Tho granophyre
Digitized by Google
Vol. 50.]
OF CAR ROCK FELL.
335
magma, mingling with the fused ultrabasic gabbro, has given rise
to abundant micropegmatitc, the appearance of which in a rock
bo rich in iron ores is very remarkable.1 Beyond this zone of rocks
are others produced by the incorporation of molten ultrabasic gabbro
into the granophyre magma, but these varieties and the general
relations between the gabbro and the granophyre will be more
properly discussed in connexion with the latter rock. It will be
noticed that the production of chemically intermediate rocks at the
junction of a basic and an acid rock, as hero recognized, has no
resemblance to the injection of solid gabbro by minute veins of
granophyre, as described by Prof. Sollas ; but phenomena compar-
able with those which he has described are also locally found. (See
PI. XVII. fig. 6, and explanation.)
The rocks distinguished at the outset as diabase will not be more
fully described. Mineralogically they resemble the gabbro, and
they reproduce in a less marked manner some of the same pheno-
mena of variation. They have certain special points of interest,
but not connected with the subject in hand. The present paper deals
specially with the variations exhibited in the large gabbro intrusion.
I hope on another occasion to show that the Carrock Foil granophyre
also exhibits considerable variations, due to another cause, and that
the Grainsgill greisen is the result of a process of differentiation
entirely distinct from that discussed in the case of the gabbro.
EXPLANATION OF THE PLATES.
Platb XVI.
Sketch-map of part of the Carrock Fell district, showing variation of gabbro.
(Scale : ft inches — 1 mile).
An attempt is made here to show the distribution of the several varieties
of gabbro and diabase. The criterion used is the specific gravity of the
rocks, and the data are shown by figures on the map. These are chiefly in
the eastern part of the gabbro area, and the dividing lines farther west are
drawn with reference to the general characters of the rocks judged by eye
and checked by a certain number of specific-gravity determinations, as shown.
The specific gravity of the gabbro is seen to increase rapidly from the central
zone to either margin. The rock here termed diabase shows much less variation.
The remarkable relations between the gabbro and the granophyre are not
shown in detail, and the numerous dykes and veins arc not marked.
The general distribution of the enclosed masses of Eycott lava* is roughly
indicated. It would be impossible to represent accurately the intricate relation
between these volcanic rocks and the enveloping gabbro.
Plate XVII.
Note.— The figures are magnified 20 diameters, and, except no. 2, are drawn
in natural light. The numbers in brackets refer to the slides, which arc in
the Woodwardian Museum, Cambridge.
Fig. 1. [79]. Gabbro. White Crags (from Mr. Ward's collection). This shows
the dominant pyroxene, an augite with fine lamcllation parallel to
the basal plane. This is combined with simple twinning parallel to
the orthopinacoid, giving the 'herring-bone' structure. The augite
is seen to mould the felspar-crystals. See p. 317.
1 No chemical analysis of this rock has yet been made. The specific gravity
of one specimen was as high as 3' 122.
2a 2
Digitized by Google
33G
MK. ALFRED HARKER ON THE OABBRO [Aug. 1894,
Fig. 2. [1867]. Gabbro, Iron Crags, about 200 yards W.N.W. of the sheep-
fold. This is drawn with polarized light (crossed niools) to show
what seems to bo secondary twin-lamellation on both the albite- and
the perieline-law in the plagioclase. In one part of the crystal the
pericline-twinning affects only alternate tdbite-laraolbc. Other
crystals in this slide show albito-lamellation in evident relation to the
strain attending flexure. The dark line is a crack in the slice. See
p. 316.
Fig. 3. [1874]. Gabbro, top of White Crags. The figure shows idiomorphic
crystals of plagioclaae moulded by a shapeless plate of more uniformly
turbid, untwinned orthoclase, well seen in the upper part of the
drawing. Lower, and to the left, is an interstitial paten of micro-
pegmatite, in which the felspathic constituent is probably also ortho-
clase. Pyroxenes and iron ores do not appear in the portion of the
slice figured. See p. 318.
Fig. 4. [2046]. Metamorphosed gabbro, Brandy Gill, 60 yards north of the
upper 4 Bield.' This is a very basic marginal variety of the rock, un-
usually rich in prisms of apatite, which are seen in abundance. The
rock is profoundly modified by thermal motamorphism, the pyroxene
being wholly transformed, partly into green actinolttic hornblende,
partly into matted patches of brown mica-scale*. The latter mineral
occurs characteristically in the neighbourhood of the grains of iron ore,
from which it has probably taken up some ferrous oxide and titanic
acid. The clear grains in the lower right-band part of the figure are
portions of one crystal of felspar, divided by narrow veins now con-
sisting of brown mica. The clearness of the felspar seems to be a
characteristic of the metamorphosed gabbros. See p. 334.
Fig. 5. [1526 and 1866]. Grains of iron ores in the gabbro. The example on
the right, from the upper part of Furthergill Sike, shows irregular
patches of magnetite (black) and ilmenitc (grey). That on the left,
from near the top of the same sike, shows the two minerals forming
parts of one idiomorphic crystal, the dividing line being parallel to a
crystal-boundary. See p. 318.
Fig. 6. [1622J. Modified Gabbro, crags in upper part of Furthergill Sike.
This is from the actual margin of the gabbro, and is a highly basic
variety, of specific gravity 3122, rich in apatite (see upper part of
figure). Nevertheless it contains quartz and micropegumtite (lower
part of figure). This is probably due to an injection of the already
consolidated gabbro by the later granophvre-magma, in the manner
described by Prof. Sollaa. At Carrock V ell this action seems to be
exceptional, and is confined to the immediate contact of the two
intrusions. Other parts of this slide and other specimens of the
samo rock show various phenomena of thermal metnmorphism in the
gabbro. Sec p. 335.
Discussion.
Mr. Marr believed that the age of the gabbro intrusion had yet
to be determined. The Author's work had for ever set at rest the
idea that the gabbro had been formed by alteration of the volcanic
rocks of the Eycott group ; for the proofs of intrusion of the gabbro
into these were complete. The mode of occurrence of the gabbro
and granophyre reminded him of the description of masses of these
rocks in Scotland, about which the Society had recently heard much.
These were points of local interest, but the main object of the paper
was to describe the variation in the different parts of the gabbro
mass, and from what he had seen of tho district he believed that
the Author had established his points.
Prof. Judd congratulated the Author of the paper on taking up this
Digitized by Google
Gab
& D
BRO V Me fAMOfi PHOSF.D
i a base Lavas Enclosed in Gabbro
■Spmfic Cnnviiy
Irss than 2 8S
triers, fJian 2 .1?
\f lr Thr iitjufr.s t/uhrtiJr tJic sf>*4 tin ./
ijnhhrv ami clta/m.*r . aj» delermitvrti t*v *
fithni /r-fttt tJiv sftnfo mnrknl X .
Digitized by Google
Quart, Journ Geol Soc Vol L PI XVI
SKKTCH-MAP OF PART OK Till.
CARROCK FELL DISTRICT.
SHEWING VARIATION OF 6ABBR0.
by Alii rd Marker, M.A..K(V.S.
Scale. 6 Inches to a Mile.
nIOPHYRE
f /\ i 7 tin-
tr-om l.tK
Google
Google
Vol. 50.]
OF C A BROCK FELL.
337
highly interesting district of Carrock Fell as a subject of study. He
. bore testimony to the careful investigation of the area by the late
Clifton Ward. The Author's observations seemed to show that
concentration by crystallizing processes might go on in a mass
of large dimensions, as well as in dykes like those described by
Lawson and Vogt.
Prof. Cole expressed the regret which all must feel that Prof.
Sollas could not be present to join in the discussion. The parallelism
of the so-called granophyre and the several layers of the basic rocks
seemed to suggest that the whole Carrock Fell mass might be a huge
composite dyke, the acid rock having intruded into the gabbro
distinctly on the north, and farther south as a plexus of minute
intorpenetrations along the central line of the gabbro, giving rise
there to the gabbro with micropegraatitic groundmass. The micro-
scopic sections seemed to him to support this view, by reason of the
contrast between the basic areas and the patches of micropegmatite.
The aggregation of iron ores on the margins of the gabbro must,
however, be explained by some such theory as that which the Author
had put forward.
Mr. Rut ley considered that one of the most interesting points in
this valuable paper was the occurrence of lavas of the Eycott series
in tho gabbro. How portions of lava-flows should become embedded
in a plutonic rock was a problem which seemed to need further
elucidation. The question whether the more acid character of the
central portion of the gabbro was due to differentiation of the
original magma, or to incorporation, by fusion, of apophyses from
the adjacent granitic rock, was an open one ; but it seemed probable
that, if the latter hypothesis were the true one, the alteration, where
tho gabbro was seen to come into contact with the granitic rock,
should extend over a wider area than that represented in the
section.
Tho Author thanked those who had spokon for their remarks,
in reply to Prof. Cole, he said that, while believing in a probable
genetic relationship between the granophyre and the gabbro, he
did not think that the injection-theory of Prof. Sollas afforded any
explanation of the regular distribution of the more or less acid
varieties of the gabbro.
Replying to Mr. Rutley, he described the occurrence of the masses
of Eycott lavas enclosed in and intricately veined by the gabbro,
but always with a sharply defined junction. All the phenomena
negatived the hypothesis of a metamorphic origin for tho latter
rock.
Digitized by Google
338
K0CK8 OP IGNEOUS ORIGIN ON DARTMOOR.
[Aug. 1894.
22. Notes on some Trachytes, Metamorphosed Tuffs, and other
Rocks of Igneous Origin on t?ie Western Flank of Dartmoor.
By Licutenant-General C. A. M'AIahon, F.G.S. (Head April
11th, 1894.)
During the last two seasons I have spent some time in the examina-
tion of the rocks of igneous origin which occur between Lydford and
Okehampton, and which are beyond the area dealt with by Mr. Frank
Rutley, F.G.S., in his memoir on the * Eruptive Rocks of Brent Tor
and its Neighbourhood.' As these rocks do not appear to have
been described, some details regarding them may be of interest.
On the Geological Survey map a long outcrop of * greenstone '
is depicted running from Great Cranaford, to the east of Sourton,
almost as far as the West Okement River. The present paper is
principally concerned with the outcrops of this ' greenstone ' on
Sourton Tors, South Down, and Meldon, and it will be found that
they embrace a considerable variety of rocks.
I. Sourton Tors.1
Sourton Tors form a ridge to the south-east of the village of Sourton
(see the accompanying sketch-map). It rises to the height of 1447
feet above the sea, and 050 feet above the village. The rocks along
this ridge crop out in two distinct lines ; one of these — that on the
western side of the ridge — forming a scries of disconnected outcrops
which I havo numbered 3, 4, 5, 10, 11, and 12; and a second or
eastern line, which I have marked 2, 6, 7, and 8 on the accompany-
ing map. The space between these two lines is covered with grass,
and the rocks between them consist, it is to be presumed, of sedi-
mentary rocks of the Carboniferous (Culm) series, similar to those
seen along the line of strike in the railway-cutting to the S.W. of
the Tors. No. 1 (of map) is on lower ground, about 447 feet below
the highest point of the Tors, and is lithologically connected with
the second outcrop. No. 9 (of map) is described in detail farther on.
The sedimentary rocks along the road between the villages of
Lake and Sourton — namely, on the western side of the Tors — dip
N.N.W. In the railway at the Lake end of Sourton Tors, tho strata
dip about 60° to the W.N.W. 10° N. On the eastern crest of the
Tors there is a small projection of a calcareous sedimentary rock
dipping N.N.W. 10° N. I am not certain, however, that it is in
place. But on the north-eastern flank of the Tors the sedimentary
carbonaceous rocks crop out in situ, near the boundary of tho Dart-
moor granite, on the left bank of a stream running down from
Sourton Tors to the West Okement River. The dip is here N.W.
10° W.
The general dip of tho rocks which form Sourton Tors may, I
think, be taken to be about N.W., and if so, the outcrop of the
rocks of igneous origin, about to be described, conforms to the dip
of the sedimentary beds.
1 ThU U written Sourton Tor (in the singular) on the one-inch Ordnance map.
Digitized by Google
Digitized by Google
340 LIEUT.-GEIf. C. A. M'MAHOX OK BOCKS OF [Aug. 1894,
The rocks of the eastern line of outcrop, 2, 6, 7, and 8, exhibit
t wo sets of joints at right angles to each other, the principal one
dipping about N. 10° W., the dip being steeper than the sides of the
hill. Both these sets of joints simulate bedding-planes, and the
apparent dip depends upon which of the two series of joints is
locally dominant.
The western line of outcrop (3, 4, 5, 10, 11, and 12 of the map)
consists of porphyritic epidiorite, to be next described.
I have examined under the microscope thin slices of specimens
from these outcrops as follows
No. I1 1137. Sp.Gr.2 97.
,. 2 1126. „ 2-92.
„ 3 1213. „ 2-91.
„ 4 1214. „ 2 86.
These are dark-grey rocks, with an almost compact matrix in
which numerous porphyritic, somewhat rounded crystals of white
felspar are embedded. They are all altered dolerites, and were
originally composed of augite and felspar. The remains of unaltered
augite may be still seen in four out of the five specimens, being
especially prominent in Nob. 2, 3, and 4.
The augite has been altered into a light-green hornblende. Some-
times the unaltered core of augite, colourless and non-pleochroic,
with an extinction-angle of from 35° to 38°, remains in the centre of
a crystal, while the pale-green pleochroic hornblende, which sur-
rounds it, extinguishes at an angle of 5 . The original augite
played the part of groundmass, the felspar appearing as large
porphyritic crystals, and also in lath-shaped prisms penetrating
into, and embedded in, the pyroxene. The felspar is intensely
altered, having been converted either into a pale-green chloritic
substance or into a serpentinous-looking isotropic mineral. Ilmenite
is very abundant in all the slices; two of them contain a little
mica ; two possess apatite ; and one of them a little granular calcite.
There is nothing to show that these rocks contained olivine.
Volcanic Tufts.
The following rocks, from the places marked 1, 2, 6, and 9 on the
accompanying map, have now to be described : —
No. 6 1127. Sp. Or. 2 80.
„ 7 1134. „ 2 79.
„ 8 1217. „ 2-77.
„ 9 1140. „ 2-75.
10 1227. „ 2-74.
„ 11 1128. „ 2-74.
„ 12 1210. „ 2 73.
„ 13 1212. „ 2 73.
1 Nos. 1 to 57 are the serial numbers of the specimens described in tbe paper,
and are given for the convenience of the reader. The higher numbers are
those marked on the hand-specimens, and refer to the author's English
Digitized by Google
Vol. 50.]
IGNKOUS ORIGIN ON DART.MOOK.
341
The above specimens have a dark-grey matrix with blebby-
looking crystals of felspar embedded in it. Several specimens also
show rounded grains of quartz on their surface ; and all exhibit,
here and there, well-formed but rectangular crystals of felspar
which give these rocks the appearance of lavas. On the other hand,
many of these rocks when oxamined in the field contain numerous
undoubted fragments of slaty, and of volcanic rocks ; and the observer
is puzzled to know whether he has before him highly metamorphosed
tuffs, or lavas crowded with included fragments.
The difficulty here presented is not at once removed by an
appeal to the microscope, and I have never examined any rocks
regarding which I felt so much difficulty in finally making up my
mind. That these beds contain a vast number of fragments of
various kinds of lavas, and of slaty rocks, cannot be questioned.
But the cementing matrix, which encloses these undoubted frag-
ments, has so completely lost all traco of its original fragmentary
origin ; it so closely resembles the base of some quartz-porphyries
and some rhyolites, and has so entirely lost all trace of the agencies
by which the change was effected, that I was for long in doubt
as to whether I was dealing with a metamorphosed tuff, or whether
some, if not all, of the beds, were lavas that had caught up the
contents of an ash-bed in the course of their flow, or had been
profusely peppered with fine ash on their road from the crater to
their final resting-place. The conclusion at which I have finally
arrived is that the majority of the beds are metamorphosed tuffs,
but that in two or three cases the rocks are really igneous flows
that have in their passage through, or over, ash-beds caught up
numerous fragments of ejected volcanic and sedimentary material.
I propose to postpone further remarks on the subject until I
have described these, and some other specimens, from another
locality. I shall make my description as brief as possible and limit
myself to salient points.
No. 0. This contains fragments of several kinds of lavas. The
rock has been considerably altered and contains much secondary
micaceous matter.
No. 7. This contains numerous fragments of lavas and of altered
sedimentary rocks. One of the former class is a vory dark glassy
lava, full of the dust of magnetite, and contains numerous small
oval vesicles and some microlitcs of felspar. Fragments of this rock
are very commonly met with in these tuffs.
The interstitial matter in which the fragments are embedded is
like the micro-granular base of some rhyolites and porphyries ; and
it eats into, corrodes, and invades some of the fragments, some
portions of which appoar to have floated off into the matrix and
to have become more or less completely detached from their parent
fragments. It is difficult to say offhand whether this corroding base
represents an intrusion into a tuff, or whether the tuff was partially
remelted after it was laid down.
No. 8. This rock is composed of numerous fragments of tho dark,
vesicular lava above described. The vesicles are stopped with a
Digitized by Google
342 LIEUT.-GKX. C. A. McMAHON ON R0CK8 OF [Aug. 1894,
pale yellowish -brown mica and in some cases with opalescent
quartz. The fragments are pierced and invaded by a cryptocrys-
talline magma, which contains a great quantity of anthophyllite.
reddish to yellowish-brown mica, and some quartz.
The anthophyllite is in bundles and sheaves of fine, needle-like,
radiating prisms without crystallographio terminations. It is
colourless in thin sections and consequently not dichroic. It pola-
rizes in the yellow of the first order ; it has straight extinction ; the
major axis is at right angles to the length of the prism ; and it is
not decomposed by prolonged heating in hydrochloric or in sulphuric
acids. Its refraction is considerable, as it exhibits sharp and dark
outlines. In a cross section I obtained two cleavages meeting at
127°. All the facts above stated seem to indicate that the mineral
is anthophyllite : it is evidently a secondary product, and occurs
principally in the base, or matrix, but it is also to be found sparsely
in the included fragments, more particularly along their margins.
The magma, or base, has frequently eaten its way into the in-
cluded fragments, these tongues sometimes terminating in a cul-de-
sac; at other times pieces of the included fragments have been
detached, drawn out into strings, and included in the fluxion of the
magma.
No. 9. Tho hand-specimen does not, on its fractured surface,
give any indication of being a clastic rock, but under the microscope
fragments of three distinct rocks can bo made out ; one a highly
crystalline lava; another a compact, buff-coloured felsite; and a third,
which may be an altered sedimentary rock or the micro-granular
base of a rhyolitic lava. A line of shear comes between fragments
of the 2nd and 3rd class, and eye-shaped patches of both rocks are
entangled with each other.
No. 10 was from a loose block not in situ, as will be explained
farther on. Macroscopically considered, the hand-specimen is seen
to contain numerous, small, slaty-looking fragments. The microscope
reveals the presence of pieces of six or seven different lavas, all
extremely fine-grained, but difforing from each other in colour and
structure. The interstitial cement (metamorphosed fine volcanic
dust that originally filled up the interstices between the fragments)
can be made out in parts of the slide ; but in other parts, its place
is taken by a rhyolite composed of two differently-coloured glasses,
and containing porphyritic crystals of quartz and felspar. This
rhyolite corrodes and invades the included fragments, and carries
off small pieces detached from them in its course. It indicates
the intrusion of a rhyolitic felsite into an ash.
No. 11. This is very much the same kind of rock as the last.
The fragments are of the same varieties of lava, and the intruding
rock is evidently the 6ame as that seen in No. 10, only it has lost its
rhyolitic character somewhat and has passed into an ordinary felsite.
The rock has ceased to bo an ash, and has become an igneous rock
full of included fragments. The fragments are not so numerous or
so closely packed as in No. 10, and probably indicate that the
rhyolitic felsite was beginning to get clear of the ash.
Digitized by Google
Vol 50.] IGNEOUS ORIGIN ON DARTMOOR. 343
No. 12. That part of the hand-specimen which is mounted on the
slide appears to be one of the slaty inclusions in one of these ash-beds .
It is of micro-granular but homogeneous structure, shows no distinc-
tive marks of igneous origin, and much resembles a slice I had
made from a slaty inclusion in a lava from this part of Sourton Tors.
No. 13. This is a rock of similar character to Nos. 10 and 11,
but the included fragments have become sparser and smaller, and
seem to have been, in most cases, nearly melted down and assimilated
by the igneous rock. Its rhyolitio character has disappeared. The
groundmass is finely crystalline-granular, with microlites of felspar
dotted about in it here and there. Sometimes these microlites are
sharply defined, and have forked ends ; at other times they are
somewhat ragged and irregular at their side edges : all of them have
straight extinction. In this groundmass are embedded numerous
porphyritic quartzes and felspars, some of which are idiomorphic.
The felspars have straight extinction, and are orthoclase; some
show a somewhat irregular polysyuthctic twinning. One large
felspar of this character, the irregular twins of which extinguish
symmetrically at 18° to 1U°, contains endo-idiomorphio crystals of
felspar with binary twins, one of which is certainly orthoclase.
This slice contains a mineral of exactly the same habit and general
character as the anthophyllite of No. 8. Some of it has a pale-
yellow tint, and some of the prisms are slightly dichroic. The ex-
tinction varies from 0° to 15°. The mineral in this case must be
actinolite: a slight rise in the percentage of iron has probably
determined the change in the optical character and species of the
mineral. The slice moreover contains magnetite, ferrite, and a mica,
which varies from buff to red in colour. The last-named mineral
also fills the vesicles in one of the included fragments of lava, as it
often does vesicles in other specimens : it dissolves readily in hot
dilute hydrochloric acid, and the solution yields a little lime and
alumina, much iron, and magnesia in perceptible amount. It also
reacts for potash. This mica must be lepidomelane or an allied
species.
Felsites.
It will bo seen from the above account of the volcanic tuffs of
Sourton Tors that the pyroclastic rocks are intercalated with felsites
containing numerous fragments of ejected material. It is not
therefore a matter for surprise to find the pure felsites (described
below) occurring among these beds.
No. 14 113*5. Sp. Or. 2 76. From plnce marked 6 on Map.
„ 15 V223. „ 2-74. „ 8 „
„ 1« 1211. ., 2 72. „ , 1 „
„ 17 1210. „ 2 72. ,. 0 „
Nos. 14 and 17 are from the same locality, and are identically
the same rocks. Macroscopically considered, they are perfectly com-
pact in texture, with blebs of quartz and very minute grains of
felspar visible here and there. They arc also traversed by fine
Digitized by Google
344
LIEDT.-GEN. C. A. McMAIION OX ROCKS OF [Aug. 1894,
quartz-veins. They have somewhat tho appearance of a metamorphic
sedimentary rock.
Under the microscope this rock, at first sight, has very much the
character of a metamorphosed sedimentary rock, and seems to. consist
of a granular mixture of quartz and flaky greenish-brown mica. On
closer examination, however, particularly with somewhat high
powers, it is seen that the matrix is by no means all composed
of quartz and mica, and that cryptocrystalline felsitic matter
predominates over the clear grains. All the water-clear grains,
moreover, are not quartz, for in some I obtained in converging
polarized light traces of biaxial interference-figures. In this granular
groundmass are scattered crystals of quartz and felspar, some of
which are idiomorphic and yield sharp crystallographic outlines.
These idiomorphic crystals afford, I think, decisive evidence of the
character of the rock. I have seen a groundmass of identically the
same structure in some undoubtedly igneous rocks, as, for instance,
in some of the laccolites of the Henry Mountains, U.S.A.
Slice No. 14 contains much, and No. 17 a little, blue schorl
in ophitic aggregations, its crystalline form being interrupted by
the granules of the groundmass. Some of the large quartzes contain
numerous liquid cavities with bubbles.
No. 15. The main constituent of this rock is a purple-brown glass,
containing countless grains of magnetite arranged in fluxion-lines,
microlites, and small prisms of felspar. The raicrolites have straight
extinction, but the small prisms are in part plagioclase and in part
orthoclase with binary twins. The glassy groundmass is vesicular,
the oval vesicles being now stopped with red iron oxide, magnetite,
and a colourless isotropic substance. The slice contains a portion
of an included fragment of a fine-grained sedimentary rock.
There are numerous lacuna? in the brown glass, and they contain
water-clear felspar, a network of green hornblende-prisms, and some
massive hornblende without crystallographic shape. Congeries of
green hornblende-prisms are also scattered through the glass.
No. 16. The groundmass of this specimen is substantially the
same as that in Nos. 14 and 17, but it contains a much larger
amount of pale-greenish mica, in scales and fibres.
Tho porphyritic crystals of quartz and felspar are extremely
abundant in this specimen. They all show very distinct remains of
crystallographic outlines ; but they are, especially the quartzes,
deeply corroded by the groundmass. The largo felspars, on the
other hand, have suffered very much from the formation of quartz
and water-clear felspar (in some cases it is certainly quartz) in their
interior. Very often this alteration has gone so far that the crystals
have acquired a very decided granophyric structure. That this is,
in these rocks, tho result of secondary alteration 1 have no doubt.
In the felspars that exhibit this structure small circular rings of
quartz, or water-clear felspar, marking the passage of liquids, or gases,
through the rock, have been left as evidence of their former presence.
The centres of these annular bodies are filled with secondary
mica, and they are sometimes fringed with the same mineral.
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
345
The record left by this rock is interesting, inasmuch as it shows
that granophyric structure may in some cases, at all events, result
from secondary alteration, and does not in these cases proceed from
hurried crystallization, and from the imperfect separation of the
quartz from the felspar at the time of consolidation.
All the felspars appear to be orthoclase, and exhibit a single
twinning combined with simultaneous extinction. In many of the
orthoclases of these rocks, however, there appear to be intergrowths
sometimes of microcline and sometimes of plagioclase. The ex-
tinctions sometimes point to the former, and sometimes to the latter
mineral.
Trachytes.
No. 18 .
1220.
Sp. Gr.
275.
From place marked
7 on
Map
„ 10
1221.
2«7.
>»
8
• •
„ 20
. 12».
>•
2-67.
• »
•»
K
„ 21
1218.
>>
2*6(5.
••
t »
7
„ 22
1219.
•»
2-65.
•>
»»
r-
4
„ 23
121o.
•>
2-03.
ti
>•
I',
<•
» 24
2-62.
»<
9
The trachytes at 0, 7, and 8 are all exposures of lava-beds
in situ ; they occur on the eastern edge of the eastern line of
outcrop, and therefore come in below the ash-beds. The spot
marked 9 is situated about 50 yards on the north side of the
crest of the ridge, and there is a bare patch here with no turf on
it, the turf having apparently been removed by the hand of man.
On this bare space there are loose blocks of trachyte (No. 24 is a
specimen taken from one of them), of ash (No. 10, described
on p. 342, is one of these), and of black, carbonaceous, sedimentary
rocks. Whether these loose detached blocks represent a bod of
coarse agglomerate cropping up in place, or whether they are
surface-detritus that accumulated here at some remote period, I
cannot say.
All the above specimens (18-24), with the exception of No. 23,
are light-coloured rocks — whitish to whitish-grey on their newly-
fractured surface — and have the rough vesicular appearance of
trachytes.
The microscopical examination of thin slices yielded the following
results : — in all except Nos. 19 and 23 the groundmass is composed
of a felted mass of microlites of felspar, with some micro-prisms of
the same mineral, of somewhat larger size. In No. 19 the ground-
mass is cryptocrystalline to micro-granular, and more resembles the
groundmass of the felsito previously described. In the great
majority of cases, and probably in all, the porphyritic felspars are
orthoclases, and exhibit binary twinning and straight extinction.
Many of them also show a very irregular striping, which some-
times is at right angles to the direction of elongation or to the plane
of binary twinning, but generally is parallel to those directions,
and indicates an intcrgrowth of microcliue or of some other spocies
of triclinic felspar. The striping has not the regularity, nor doe*
it exhibit the straight planes, of plagioclase ; and in many cases
Digitized by Google
346
LIEUT.-GEN. C. A. M'MAHON ON ROCKS OF [Aug. 1 894,
the extinction is 15° from the plane of twinning in both sets of
polysynthetic twins, or straight in one set and approximately 15°
in the other set of twins. This is very characteristic of all the
orthoclases in the lavas in this vicinity, and shows that intergrowths
of microcline with orthoclase are not uncommon. The cross hatch-
ing, so commonly seen in the microcline of granites, has not been
observed in these rocks. In many cases the felspars are idiomorphic.
Nos. 19 and 20 contain grains of free quartz in the groundmass,
and these possess liquid inclusions with bubbles.
All the slices contain matted fibrous masses, and more or less
radiating tufts, of fine needle-like prisms of actinolite. In habit it
is like the authophyllite of No. 8 ; in these slices it varies in
colour from a palc-greenish to a brownish-yellow. Here and there
it is slightly dichroic. The angle of extinction varies from 0J to
16° ; the major axis of elasticity is at a high angle to the length
of the prisms; and the mineral is not acted on by prolonged
heating in concentrated hydrochloric acid.
The secondary origin of the actinolite is evident from the fact
that it extends, in some cases, from the body of the rock into the
quartz- veins that traverse some of the slices. This is an interesting
fact, as it shows that the genesis of the actinolite was contemporaneous
with the formation of the quartz-veins. As the quartz in these veins
contains liquid cavities and bubbles, I think it probable that the
actinolite and the quartz are both due to the contact-action of the
neighbouring Dartmoor granite. In No. 20 the actinolite is of dis-
tinctly yellow tint and seems to be on the road to conversion into
epidote. In double refraction, however, it is far from this mineral.
All the slices contain more or less magnetite, ilmenite, or ferrite.
No. 21 contains some lacuna} stopped with a chloritic-serpcnt-
inous mineral associated with quartz. No. 22 contains apatite,
No. 19 a little haematite, and a red to green mica in leaves and
radiating fibres. Digestion in hot concentrated hydrochloric acid
removes much of the colouring matter, but does not dissolve the mica.
No. 23 is darker in colour than the specimens described under
the head of 4 trachytes,' being a light greenish-grey on the freshly-
fractured surface, and rusty -looking on its weathered face. Decom-
position has advanced so far in this specimen that I find it
impossible to state definitely what its original structure was. It
seems to have been a lava, and that is all I can say.
Remains of what appear to have been fclspar-microlites and fine
lath-shaped prisms of that mineral can be made out, but they are
highly altered ; they have straight extinction. The slice is
profusely dappled with leucoxeno after ilmenite, the inclusions in
the original ilmenite remaining. There are also a few specks of
magnetite or ilmenite.
The slice contains an abundance of calcite, in tabular twinned
crystals and dotted all over the field in minute granules. A pale
yellowish- green to almost colourless, serpentinous-looking, isotropic,
and structureless substance occurs in patches and in lacunae.
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
347
No. 23 also contains sphenc and apatite. The former is rather
abundant in small granules and crystals : it is a secondary product,
sometimes embedded in the serpentinous substance, and at other
times associated with the leucoxene.
II. Meldon. — West Okemknt River.
At Meldon, under and near the railway viaduct, there are some
interesting rocks, the outcrop of which is entered in De la Heche's
geological map as ' greenstone.' Owing to vegetation and talus, no
actual exposuro of these rocks can be seen on the banks of the river
below the viaduct, and their relationship to the sedimentary series
cannot be made out from an examination of the bed of the stream ;
but, judging from the manner in which they crop out higher up, and
on the downs above, the 4 greenstones * appear to run with the
bedding of the Carboniferous strata, and to dip at the same angle
and in the same direction as these.
The following specimens from the outcrop adjoining tbo viaduct
have been sliced and examined : —
Volcanic Tuffs.
No. 26 1196. Sp. Or. 2 71.
„ 2tf 1197. 2 72.
„ 27 1198. „ 270.
Viewed macroscopically No. 25 would, I think, be taken for a
lava; for, besides Webby crystals of felspar in a compact base,
there are many small, lath-shaped, idiomorphic crystals of the same
mineral orientated in various directions. A prolonged study of this
specimen under the microscope has, however, satisfied me that we
have here only an ash which has suffered from contact-metamorphism.
The rock is really compounded of fragments of trachy tic, felsitic, and
other lavas of somewhat more basio character, cemented together
in what now looks like the base of a felsite. This cement, or
base, contains great quantities of the anthophyllite described under
No. 8 (p. 342).
The slice also contains a reddish-brown mica, a little quartz, and
dots of magnetite or ilmenite, leucoxene, and ferrite.
Owing to the fragments of which the rock is composed being of
much the same colour as the matrix, it is only here and there that
the unaided eye is able to distinguish between them. Many of the
lath-shaped prisms may therefore belong to included fragments,
and not to the matrix, but I am prepared to admit the possibility
that they may be the products of metaraorphism.
Nos. 26 and 27 are rocks of a similar character. The melting-
down process has gone so far in these specimens that they simulate
very closely the appearance of igneous rocks, and they might easily
be taken for rhyolites. They betray their origin, however, by the
numerous fragments of different kinds of lavas which they contain.
Alteration has proceeded very far in both specimens. Mica in
Digitized by Google
LIKUT.-OE5. C. A. MrMA.UON ON ROCKS OP [Aug. 1 894,
scales has been profusely formed in the matrix, and also in the
felspars, producing, in some cases, the appearance of their having
been corroded by the groundmass. Dots of magnetite are arranged
in flowing lines, and there is a general appearance of fluxion-
structure, especially in No. 26. It does not seem necessary, how-
ever, to assume that any extensive movement of the ash actually took
place. These fluxion-lines may only indicato that the fine volcanic
dust was arranged in flowing lines of lamination round the larger
fragments, and gave a direction to the heated aqueous agencies
that subsequently acted on the rock. On the other hand, the
very fine dust that must have formed the original interstitial
portion of these ashes, when subjected to the aquose heat radiating
from the great masses of Dartmoor granite may have become
sufficiently plastic to assume a fluxion-structure under the stress of
some of those minor earth-movements, or tremors, that were
doubtless abundant in this region during the time when the granite
was cooling down.
No. 26 must have been at one time in a plastic condition and
must have been subjected to some pressure, because in one place an
elongated felspar is bent round an included fragment, and cracked
transversely in several places. But the amount of movement
and shearing must have been slight, because several sharp angular
fragments and felspars stand up boldly at right angles to the
lines of apparent fluxion, and the felspars have not become eye-
shaped, but, on the contrary, retain the sharp-broken, fragmentary
outlines which they received when blown out of the mouth of the
crater. Most of the cracks in these felspar-fragments are probably
due to the explosion which ejected them from the crater; but the
rock was, I conceive, subsequently subjected to partial aqueous-
fusion and compression. I regard this specimen as a very beautiful
example of the way in which a pyroclastic rock may, under the
influence of powerful contact-metamorphism, be made to assume
the appearance of a lava.
Near the railway viaduct some of the agglomeratic beds contain
quite largo blocks of slaty and felspathic rocks, of all sizes and
shapes. I have examined a fragment from one of these blocks : —
No. 28, 1160. This is a fragment of a felsite. The matrix is
microcrystalline-granular and contains porphyritic crystals of
felspar and quartz, with dots of magnetite, ferrite, and leucoxene.
These crystals have suffered corrosion from the base.
This slice is chiefly interesting, because the production of
granophyric structure in one of the felspars appears to be directly
connected with a quartz-vein that runs up to it. This vein is not
an aqueous infiltration along a crack : the margins are not
straight, well-defined lines ; and the quartz appears to have eaten
into the matrix on either side of the vein. This case supports the
opinion expressed in describing No. 16 (p. 3*5), that granophyric
structure in some cases, at all events, is due to secondary alteration.
In this connexion it may be desirable to allude to a vein that, at
Digitized by Google
Vol. 50.]
I6NK0U8 ORIGIN 0!» DARTMOOR.
340
the time of my visit, was to be seen cutting across t hese altered ash-
beds, at right angles to their strike. I sliced and examined a spe-
cimen of it, No. 29, 1161. The slice is composed entirely of quartz
and a pale yellowish-red mica. Some of the mica is in radiating
groups : it has little dichroism and feeble double refraction. There
are also colonies of colourless belonites. The quartz is like the
quartz of the neighbouring granite : it contains a profusion of gas
and liquid cavities, some separate, some combined. Some of the
liquid cavities contain three or four rectangular crystals, as well
as a bubble.
It is not improbable that this quartz-veio emanated from the
white granite of Meldon, which is at no great distance. 1 mention
the occurrence of this vein for what it is worth, as other better
examples may hereafter be found ; and such veins, if they can be
associated with the granite, will elucidate the question of the relative
ages of the granite and the rocks of volcanic origin in this locality.
On the Geological Survey map, another outcrop of ' greenstone '
is marked to the S.E. of the white granite between Black Down and
Longstone HilL On going up from a tributary of the West Okement
Itiver and mounting the flank of the Black Down, blocks of this
outcrop are seen which weather like a coarse-grained agglomerate.
The dip of the rocks here i* N. 20° W.
Volcanic Tuffs.
1200. 8p. Gr. 2-70. 1 e ... ,
1*H)1 **-69 I ^Peclmen8 of tlie9e rock*
1202. „ 2*tf9. Matrix of this agglomerate.
1203. „ 2-ttf. One of the included block*.
No. 30 is made up of fragments of trachyte, and of altered
sedimentary rocks embedded in a very fine-grained microcrystal-
line-granular matrix, which equals in amount, if it dooa not
predominate over the fragments. The matrix must originally have,
been a very fine dust. No. 31 is so completely composed of trachyte
that its clastic structure is not at first apparent. This, however,
came out moro clearly in a second and thicker slice, which 1 had
prepared for chemical purposes, particularly before it was subjected
to the action of hot acid.
No. 32 is the matrix of a coarse-grained agglomerate, and 33 is
a portion of a large included fragment. Under the microscope
No. 32 is seen to be made up of fragments of trachytic and altered
sedimentary rocks, embedded in a microcrystalline-granular ground-
mass. No. 33 is a piece of trachyte traversed by several quartz-
veins, which, as is commonly the case in these rocks, exhibits a
micro-tessellar structure.
All the slices contain a profusion of mica varying in colour in
transmitted light, from orange to greenish-brown ; the mineral is
completely soluble in hot, dilute hydrochloric acid. The solution
contains iron, alumina, magnesia, lime, and potash, and the mica
therefore appears to be some species allied to lepidomelane.
Q.J.U.S. No. 199. 2 b
No. 30
„ 31
„ 32
11 33
Digitized by Google
350 LIEUT.-GBK. C A. MeMAHOX OK BOCKS OP [Aug. 1894,
All the slices contain magnetite. Nos. 30 and 32 contain much,
and 33 a little anthophyllite with the habit already described.
III. South Down.
On the left bank of the West Okement River, opposite Meldon, a
ridge rises abruptly from the river, and stretches away until it
widens out into South Down and ultimately merges into Sourtou
Tors.
I may note in passing that I discovered, last year, a second
outcrop of the Meldon white granite on the eastern flank of South
Down. It is not on the spot where a second outcrop is marked on
the Survey map, which I stated in my last paper that I was unable
to find. That is placed on the right bank of the river, extending
in a northerly direction across to the left bank. The outcrop which
t found is away from the river altogether, on the eastern side of
South Down, some 300 feet above the West Okement River. A
small quarry has been opened here, and the rock has exactly the
same appearance as that of Meldon. The latter is, as the crow flies,
about 5 mile distant in a north-easterly direction.
In the Carboniferous slaty rocks that compose the ridge running
up from the West Okement River to South Down, and at a lower
horizon than the Meldon limestone, a plagioclase-mica-hornblende
rock occurs which merits notice. It is a compact igneous rock of
purple-grey colour which has the appearance, in the field, of being
a contemporaneous lava. It runs with the sedimentary rocks ; and
although, owing to vegetation, its outcrop is not continuous, it is
always found under a dark-blue slaty Carboniferous rock, that, in
the field, is somewhat suggestive of a limestone. Though the mica-
diorite disappears from view occasionally, it can always be found
cropping up again farther along the line of strike.
The Carboniferous beds dip N.W. 15° N. at the foot of the ridge ;
higher up they dip N. 20° W. This dip continues until a wall is
reached, which forms the boundary between the top of the ridge
and the beginning of South Down : here the rocks make a sharp
bend, the strike becoming N.E. 10° N. On the top of South Down
the dip turns over to W.N.W. ; that is to say, it reverts approxi-
mately to what it was in the bed of the West Okement River at the
foot of the ridge.
The mica-diorite now described crops out first (specimen 35) on the
flank of the spur, or ridge, just above the river. It rises to the crest
of the ridge (specimens 34 and 36), and, owing to the sharp bend in
the strike of the rocks above alluded to, it passes along the eastern
side of South Down. I have not traced it beyond that point.
In my last paper I pointed out that De la Beche's geological map
is not to be relied on too implicitly for the boundaries of the
4 greenstone '-outcrops marked on it. The case in point is another
instance of this ; a continuous outcrop is indicated from the West
Okement River over South Down to Great Cranaford. No such
outcrop exists : the rocks of igneous origin visible along this line
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN OX DARTMOOR.
351
are in discontinuous outcrops, and the rocks themselves, as has been
shown above under the head of Sourton Tors, differ materially from
each other.
The following specimens of the rock under description were
examined : —
Mica-diorite.
No. 34 1144. 8p.Gr. 2 81.
„ 35 1205. „ 2-70.
86 1207. „ 2'7'J.
The microscopical examination of these specimens shows that
the rock is a mica-diorite. The groundmass consists of a meshwork
of small plagioclase-prisms, some of which are sufficiently large to
show porphyritic crystals. The next most abundant mineral is a
red mica ; this is profusely scattered over the thin slices in all the
specimens, and to its abundance the purple tone of the grey colour
of the rock is due. It is, I think, a secondary contact-mineral.
Hornblende is not a prominent mineral, and it is altogether absent
in No. 35. This mineral occurs in shapeless aggregates of graius,
or in stumpy allotriomorphic prisms. In transmitted light it varies
from a pale brownish-dun colour to a very pale undecided greeu.
It is dichroic only here and there, and never strongly so. Only one
cleavage is distinctly seen ; and when a trace of a second cleavage
is to be observed (which is rarely the case), it approximates in its
angle of intersection more to hornblende than to augite. Extinction
varies from 12° to 28 measured from the single cleavage, and
averages 18°.
Sphene is abundant ; so is apatite ; and there is a fair amount of
magnetite or ilmcuite.
In the triclinic felspars extinction is often nearly simultaneous in
both sets of twins, and is nearly straight. In others it vuries from
6'° to 14° from the plane of twinning on P, and averages 10| J.
IV. On the Flank op Cock's Tor.
High up on the southern flank of Cock 8 Tor, above the Tavistock
and Moreton Hampstead road, there is an interesting outcrop of
rocks, which have not, so far as I am aware, been described, or indeed
noticed, by previous observers. These rocks stand out from the
hillside in a low cliff about 12 feet high, and for a length of 40 or 50
feet. They weather out into lines suggestive of lamination, which
impart a ribbed appearance, somewhat like that of corduroy cloth,
to the beds. They have a low dip to the N.N.W. 10° W.
The ribbed appearance above alluded to is well seen on the
weathered surface of one of my hand-specimens (38), and it is
represented in the illustrution (fig. 1, p. 352).
On the occasion of my first visit to this locality, in 1892, I col-
lected the specimens numbered 45 to 47 ; but at my last visit in
1893 I made a more complete collection, in ascending order, which
I enumerate on the following page : —
2b2
Digitized by Google
352 LIECT.-OEH. C. A. MfMAHOJi OK ROCKS OF [-^ug- I S94,
Pig. 1. — Specimen of metamorphosed tuff showing 'corduroy
structure.'
[From a photograph.]
Collected in 1893.
No. 37 1*230. Sp. Gr. 2fi8. Bottom ben*.
,. 38 1281. „ 3 15. Next abo\e No. 37.
ii • !-•>-. || — Hft. if ti ii
„ 40 1233. „ 8*15 , 39.
„ 41 1234. „ 3-03. ,. „ „ 40.
„ 42 1235. „ 2<->5. „ „ „ 41.
,.43 12G6. „ 3 24 „ 42.
Om^n. Grass.
No. 44 1267. „ 2 87. Apparently in »ifu, about 2 or
3 feet above 43.
Collected in 1S92.
No. 45 1118. Sp. Gr. 2 09. Cornea in adjoining No. 42.
.. 4« 11 Ml. „ 327. „ 38.
„ 47 1120. „ 3- 19 39.
Grass follows No. 44, and then at a distance of 20 yards the
epidiorite of Cock's Tor crops out apparently in situ.
The hand-specimens of the above rocks are all compact, and vary
in colour from a yellowish to a greenish- prey. One, No. 41, appears
to be composed of two distinct layers : one of a greenish and the
other of a purplish tint. Some other hand-specimens, when examined
with a pocket-lens, arc seen to have reddish felspathic streaks. The
fraet tired surface looks very much like a compact igneous rock.
I now proceed to give the results of the examination of thin slices
of the above specimens under the microscope.
Vol. 50.]
IGICEOUS ORIGIN ON DARTMOOR.
353
No. 37, the bottom bed, appears to bo a true sedimentary rock.
The fractured surface, examined macroscopically, resembles a slate,
und it has two parallel white streaks running across it. This
impression is confirmed by an appeal to the microscope. A fine-
grained parallelism of structure pervades the whole slice : the micro-
grains are arranged in parallel lines; and there are streaks of
lighter colour running parallel to each other and to the alignment
of the grains. The slice contains no porphyritic crystals ; it is made
up of minute colourless granules, crowded with microscopic fibres
and leaves of mica. It coutains strings of ferrite, and a fine-grained
white substance, opaque in transmitted light, that may be kaolin.
This rock is evidently a variety of slate.
Nob. 38, 40, 43, and 46, the specific gravity of which varies from
3*15 to 3*27, are shown by their microscopical characters to be
identically the same rock. They are all composed alike of masses
of augite-crystals set in a felsitic base. Sphene is plentiful in
No. 40 and is present iu No. 40. Apatite is abundant in No. 40.
The base is quite subordinate to the augite. In ordinary trans-
mitted light it is of a reddish-buff colour, and, with the exception of
No. 40, it is without any structure ; it looks like, and plays the
part of a glassy base. Between crossed nicols it breaks up into
allotriomorphic masses of dimly-polarizing felspar. In No. 43 this
base, or groundmass, is paler iu colour ; and though it is allotrio-
morphic as regards the augite, and shows no internal crystalline
shape, it exhibits a single cleavage and straight extinction.
The augite is of a very pale greenish or bluish-green tint, but is
nearly colourless. It is massed together in stumpy prisms, which
rarely show its crystalline form perfectly. Bometimes, however,
the cross-cleavage and the shape are typically developed. The
extinction measured from a well-marked single cleavage usually
varies from 35^ to4oJ. When cross-cleavages are visible the biaxial
interference-figure, as in typical augite, can be seen.
Here and there, this nearly colourless augite has occasionally been
converted in situ into a strongly pleochroic, greenish-blue hornblende;
but the augite is, on the whole, extremely fresh, and the proportion
of the paramorphic hornblende to the unaltered augite is very small.
In Nob. 31) and 47 the augite is in microscopic grains, and the
base,' when examined between crossed nicols, differs from the base of
the specimens previously described, inasmuch as it exhibits a micro-
crystalline-granular structure — like the base of some rhyolitic rocks
and the matrix of the tuffs at iSourton Tors and Meldon. Both
specimens contain sphene, and No. 39 contains apatite and a little
secondary hornblende. The comparative lowness of the specific
gravity of No. 159, namely 2*85, is apparently due to the increase in
the proportion of the acid base to the basic augite
1 I prefer this term, in the case of theae rock*, to ' groundraaM,' because in
ordinary transmitted light it is without structure, looking like and playing the
part of a glaasy base.
Digitized by Google
LIEUT.-OBN. C. A. MfMAH05 ON SOCKS OF [Aug. 1894,
No. 41, both macro- and microscopically considered, is seen to be
made up of two distinct layers. Under the microscope the purplish
layer is seen to be almost wholly composted of fine granular augite,
with a small proportion of the reddish buff-coloured felspathic base.
The second, and greenish-coloured layer is made up of minute,
slightly-elongated and irregularly-shaped grains of felspathic material
that has a distinctly lamellar structure. This is dappled over with
a granular, translucent to opaque substauce, for which I have no
name. Between these two layers the augite has passed into dichroic,
finely granular hornblende.
No. 42 is essentially the same rock as the green portion of No. 41.
The felspathic base is predominant and the pyroxene subordinate ;
hence the comparatively low specific gravity (205) of this specimen .
The rock is composed of the felspathic base (in which a lamellar
arrangement of the materials is apparent), with greenish hornblende,
a little augite, some ferrite and opacite, a little sphene, and a little
secondary quartz associated with the hornblende. The hornblende
exhibits a linear arrangement of its crystals and granules parallel
to the lamellar structure of the base, and is apparently due to the
action of heated water acting along these lines of lamination.
No. 45 is essentially the same rock as the last. The lamellar
arrangement above alluded to is not apparent in the base, and con-
sequently this structure is not seen in the hornblende ; but the
study of this specimen leaves no doubt of the fact that the formation
of this secondary hornblende is connected with the action of heated
aqueous agencies, for one side of tho hand-specimen (originally, I
presume, the wall of a crack) is covered with hornblende, and
numerous microscopic cracks, lined with this mineral and leading
up to and traversing hornblende-crystals, may be seen in the slice.
These crystals are in the form of more or less regular rhombs (the
prismatic angle of one of them is 120°); internally they are made
up of minute granular patches of hornblende, which here and there
coalesce to form homogeneous platy crystals, exhibiting a single
cleavage from which the angle of extinction measures 0° to 12°,
with an average of 8°. Dichroism is distinct, though somewhat
feeble. Extinction in the small patches is not always uniform
throughout the rhomb, but this may be due to imperfect twinning.
This slice affords a very instructive example of the mode in w hich
much of the secondary hornblende in these rocks owes its birth to
active aquoous agencies permeating the pores of tho rock.
No. 44 is a highly altered rock. It is composed principally of
what appears to have once been a felspathic base and actinolite.
In some parts of the slice there is much of what is probably zoisite ;
it is colourless, and its double refraction is so low as to bo practically
nil. One of my slices of this rock contains an abundance of sphene
in grains and some iron, probably ilinenite.
The actinolite is of a pale green colour and occurs generally in
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
3f>5
radiating fibrous crystals. Prolonged heating in concentrated hydro-
chloric acid has no effect upon it. It polarizes well, and, when the
slice is sufficiently thick, exhibits pleochroism.
The original base has been altered into a serpentinous product,
which is probably related to pseudophite.
These interesting rocks of Cock's Tor remind me very forcibly of
some of the hornblende-schists of the Lizard. I allude to thut
variety of the Lizard hornblende-schists which is supposed to have
been originally a volcanic tuff. This origin was attributed to the
Lizard schists by De la Beche long ago, and was adopted in my
first paper on the Lizard rocks.1 In tho joint paper subsequently
written by Prof. Bonney and myself,2 we stated that the rocks of
the Hornblendic Group " must originally have been of igneous origin ;
the more massive may represent altered basaltic lavas, the more
banded altered tuffs of similar composition/' 3 And whilst the fluxion
hypothesis was invoked to explain the present foliated schistose
character of former lava-flows, we were of opinion that "the possi-
bility of some portions [of the Lizard hornblende-schists] having
resulted from the alteration of a stratified basic ash must not be left
out of sight." *
My first paper showed that the Lizard hornblende-schists contain
a colourless augite, and I expressed the opinion that the hornblende
which enters so largely into tho composition of these schists was a
secondary product after augite. In these Lizard rocks the derivation
of the hornblende from the augite could be clearly demonstrated by
microscopical evidence.
In the rocks on the flank of Cock's Tor described in these pages,
we have, it seems to me, horn blende-schists, similar to those of tho
Lizard, in an early stage of their development. In both we find
almost colourless augite set in a felspathic base, or in felspar that
plays the part of a base.5 In the Lizard rocks the augite has nearly
all been converted into hornblende ; in the rocks of Cock's Tor this
process has only just commenced, and we can see it in its first stages.
The microscopical evidence demonstrated clearly that aqueous
agencies were the cause of the change of the augite into hornblende
in the Lizard schists. In the case of the rocks of Cocks Tor, I
think the evidence points to the same conclusion.
An original fragmentary origin was predicated for the Lizard
hornbleude-schiBts oh the grounds that they exhibited structures
suggestive of stratification and even of * false bedding,' and that
their chemical analysis and mineralogical composition indicated
an igneous origin/ In the case of the Cock's Tor rocks, similar
and even stronger grounds exist for considering them to be highly
altered ash-beds. Their mode of occurrence ia not only suggestive of
bedding, but they bear on their face evidence of original lamination.
' Quart. Journ. Geol. Soe. toI. Jt. (1889) p. 519.
» Ibid. p. 478.
4 Op.dt. vol. xIt. (1889) p. 521.
Digitized by Google
350
ROCKS OF IG5K0F8 OKIfllH 05 DA RTHOOR.
[Aug. 1S94
Weathering often brings ont the original structure of rocks when
the clean-fractured surface does not betray it, and the Cock's Tor
beds are a case in point. The lines of original lamination weather
out in a way which imparts to the weathered surface a peculiar
ribbed appearance like that of corduroy cloth ; this indicates, in my
opinion, that these beds were originally sedimeutary rocks deposited
in thin layers. This structure is not only apparent in the field,
but it is well seen on the weathered surface of one of my hand-
specimens, which was selected for microscopic examination and not
for the purpose of showing the surface-ribbing. The illustration
(fig. 1) on p. 352, reproduced from a photograph of specimen No. 38,
illustrates this fairly well, but the original, u hen seen in a suitable
light, shows the lamination even more strikingly, because the growth
of lichen and the consequent variation in tint somewhat interfered
with the snccess of the photograph.
Evidence of this lamination is not altogether confined to the
weathered surface of the rocks ; it can be seen in some of the thin
slices under the microscope, as for instance in Nos. 41 and 42.
The linear arrangement of the felspathic portions of these slices,
when seen between crossed nicols, is precisely that of a fine-grained
aqueous sediment, and could be perfectly matched in numerous
examples which I possess of the indurated slaty rocks of the Culm
series bordering the Dartmoor granite.
The rocks (38-47) above described are mainly composed of
pyroxene and felspar ; they do not contain any water- worn grains
of quartz, and their specific gravity averages as high as 3 00.
The above facts, taken together, seem to leave little, if any,
reasonable doubt as to the origin of the rocks, and to show that
they were once fine-grained beds of volcanic ash. Their high specific
gravity, their mineral contents, and the absence of water-worn grains
of quartz put the supposition of their being ordinary sedimentary
Tocks wholly out of the question; and the laminated structure,
apparent on their weathered surface, is against the notion of their
being igneous crystalline rocks. Moreover, their internal structure
under the microscope is unlike that of any eruptive rock I have ever
seen.
In order to compare these rocks with some of the Lizard schists,
I selected for examination specimens taken from a quarry between
I^andewednack Church and Cove ( Lizard ). These are typical schists :
they still contain some unaltered augite, and are without any free
quartz. The specific gravity of the three samples examined was as
follows :— (1 ) 3-00, (2) 3-05, (3) 3-17 (average 3-07). Their specific
gravity, therefore, corresponds very closely with that of the ten
Cock's Tor specimens.
I reproduce on the opposite page a sketch of a portion of No. 38
from Cock's Tor, as seen under the microscope, and a sketch of one of
the Landcwcdnaek specimens, above alluded to, for comparison. The
structureless portion in fig. 3 represents the felspathic base : the lights
shaded part is the augite, and the dark-shaded part the secondary
hornblende. 1 selected that portion of the Lizard slice in which the
Fig. 2. — Metamorphosed asJi on the flank' of Cock's Tor : Auyite-
crystals in a felspathic base. ( X 60 diameters.)
Fig. 3. — HornMende-srhist, Lizard : Awjite ami hornblende in a
fefopathic base, (x 60 diameters.)
:*58
LIEUT.-0E5. C. A. M'MADON ON BOCKS OP [Aug. 1894,
augite was most abundant. The slice depicted in fig. 2 consists of
felspathic base and augite ; it contains very little hornblende, and
the shading given by the artist is somewhat misleading in this
respect.
Assuming that these rocks were originally ashes, it is evident
that they must have suffered considerable metamorphism since they
were laid down. There is no difficulty in accounting for this:
the rocks under description occur within a few yards of the Cock's
Tor epidiorite, and the epidiorites of this area are believed by
previous writers to have exercised a metamorphic influence on the
strata adjoining them.1 Then the altered ash-beds here described
aro less than \ mile from the main muss of the Dartmoor granite, and
in its underground extension the granite may be even nearer than
this. A subterranean connexion between the granite of Dartmoor
and Brown Willy has been considered probable by those who have
already written on the subject, from De la Bcche to Ussher.* The
rocks under consideration lie near the axis of this supposed under-
ground extension of the granite, and the potency of the contact-
raetamorphism exercised by the Dartmoor granite has been admitted
by numerous observers.3
As the massive dolerites, now epidiorites, have suffered so many
mineral changes from the presence of the granite, it does not make
a severe demand on our faith to believe that beds of finely triturated
volcanic dust also felt the effects of the contact-action of the great
mass of the Dartmoor granite, and of its underground extension
between Dartmoor and Brown Willy.
These Cock's Tor beds appear to have been sufficiently distant
from the nearest crater to have escaped the shower of coarse
materials, and to have received only the fine dust borne upon the
wind. No one who is acquainted with the history of Pompeii and
Herculaneum, and has seen the deep and fine-grained deposits
under which those cities are buried, need hesitate in believing
that beds of equally fine-grained volcanic material, devoid of large
fragments, may have been deposited at Cock's Tor. If so, I 6ee
no difficulty in going a step farther, and supposing that when .
the finely triturated particles of highly basic lava, charged with
water, were subjected to the long-sustained heat and pressure
which must have resulted from the intrusion of the great mass of
Dartmoor granite, a reconstruction of the materials took place, and
pyroxene and felspar were formed.
1 I express no opinion on ibis point myself. The subsequent metamorphism
by the granite renders the testing of this conclusion very difficult.
a W. A. E. Ussher, ' British Culm Measures,' Proc. Somerset Arcbseol. k
Nat. Hist. Soc. vol. xxrviii. (1892) p. 193, where De la Beche is quoted.
* Ibid. p. 209 ; see also Teall, 4 Brit. Petrography,' p. 234 ; Worth, ' Rocks
of Plymouth/ Trans. Plym. Inst. vol. ix. (1886) pp. 242-246 ; De la Beche,
' Report on the Geology of Cornwall, Devon, and West Somerset,' 1839, p. 267 ;
Allport, Quart, Journ. Geol. Soc. vol.xnii. (1876) p. 421 ; Rutley. Geol. Surv.
Mem. ' Brent Tor.' p. 25 ; and the writers previous paper, Quart. Journ. Geol.
Soc. vol. xlix. (1893) p. 389.
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
359
That the results obtained at Cock's Tor differed from those which
followed the metamorphism of the Sourton Tors-Meldon ash-beds
was probably due to some slight difference in the chemical and
mineralogieal character of the lavas that supplied the fine-grained
interstitial material at Sourton Tors and Meld on, and the volcanic
dust of Cock's Tor. There may also have been some slight difference
in the circumstances that governed the metamorphism in the two
cases. There may have been more water, or the water may have
been more highly charged with acid, in the one locality than in the
other ; or there may have been greater heat, or some other factor,
present in the one case that was absent in the other.
However this may have been, there is no escape from the fact that
the Cock's Tor rocks aro now composed of augite and felspar, and
that these beds on their weathered surface give evidence of having
once been laminated deposit*. As theso beds occur in an area that
abounds in volcanic ash, and as this portion of the area exhibits
contact-metamorphism of a pronounced kiud, I think the most
reasonable and probable conclusion to form is that they are tuffs
which have been altered by contact-metamorphiam.
In my first paper on the Lizard rocks I showed 1 that the horn-
blende of the schists was a secondary product due to the alteration
of augite by aqueous agencies, and that examples of this change
in all its stages can be seen in thin slices of these rocks when
examined under the microscope ; also that the rocks give
44 abundant evidence of the presence and action of water." 44 The
competence," I added, 44 of this agent, aided by heat and pressure,
to bring about great mineralogieal and structural changes, can
hardly bo doubted. Indeed, the Lizard rocks have been penetrated
by and have yielded to the action of aqueous influences so completely
that they may almost be said to have been stewed in w ater."
The Cock's Tor rocks exhibit the same changes and the same
agencies, only in a lesser degree. Here and there small portions of
almost colourless augite-erystals (I speak of their appearance in
transmitted light under the microscope) have been converted into a
strongly pleochroic bluish-green hornblende — the beginning of those
changes that would in time, and under favourable circumstances,
have converted the metamorphosed ash-beds of Cook's Tor into
hornblende-schists, indistinguishable from the Lizard hornblende-
schists of tufaceous origin.
That the changes set up in the Lizard rocks have proceeded
further than the changes begun in those of Cock's Tor may l>e
owing to the circumstance that the rocks of the Lizard formed the
roots of an ancient mountain-range, and were presumably more
exposed than the Cock's Tor beds to the heat and pressure that
gave greater potency to the aqueous agents at work : for the Cock's
Tor beds, it is to be presumed, lay nearer the surface, and were
consequently less involved in the pangs and throes of mountain-
making.
1 Quart. Journ. GeoL Soc. vol. xlv. (1889) pp. 522-527.
Digitized by Google
360 LIBUT.-OMT. C. A. M'MAHO* OJf BOCKS OF [Aug. 1 894,
That hydrothertnal agents played an important part in the forma-
tion of hornblende in the Cock's Tor beds is clear from the fact that
some of my slices contain microscopic cracks stopped with this
mineral, and a macroscopic crack on one of my hand-specimens was
filled with the same material.
It may be convenient, before passing on to another locality, to
compare the altered ash-beds (38-44), above described, with the
nearest sedimentary beds.
No. 37, which conformably underlies these beds, would do well,
so far as its lithological appearance is concerned, lor one of the
bottom Culm series. It looks like an indurated and altered Culm
slate.
The next nearest bed that I was able to find cropped up on the
side of the Tavistock and Moreton Hampstead road, under Cock's
Tor, about $ mile 8.W. of the altered ash-beds above described. I
have two specimens of this rock, but they are so exactly similar to
each other that I need only describe one of them — viz., No. 48, 1110*,
specifio gravity 2*74. Macro- and microscopically considered, this
is much more highly metamorphosed than No. 37. Indeed, it is as
much metamorphosed as the highly altered Devonian beds in the
neighbourhood of Shaugh.
No. 48 is a fine-grained, spotted schist, with an unctuous feel.
Under the microscope it is seen to be composed of plates and fibres
of mica and fine-grained, irregularly-shaped granules of quartz. It
is profusely dotted with countless grains of opaque to translucent
ferrite, which imparts a redness to some of the mica, the colouring
matter being diffused in streaks across the slice. The whole slice,
under the microscope, has a streaky structure, and the spots are due
to segregations of mica.
In Mr. Ussher's map, No. 1 (* The British Culm Measures '),
the country east of Tavistock is marked as * Culm or Devonian.'
As regards the above-mentioned outcrops, I think No. 37 is
probably Lower Culm ; but I consider No. 48, on lithological and
penological grounds, as undoubtedly Devonian.
V. The Brent Tor Series.
It is not my intention to enter into any details regarding the Brent
Tor volcanic rocks, so well described by Mr. Frank Rutley, F.G.S.,
in his work already referred to ; but a few supplementary remarks,
regarding rocks not noticed in bis memoir, may not be out of place.
Due north of St. Michael's Church, which crowns the top of
Brent Tor, on the side of the high road leading to the Tor, not far
N.E. of the Stag's Head Inn, and S.E. of the old chimney of the
abandoned mine at Moukstone, there is a pit from which the
country rock is at present taken for road-material. This pit had
not, I believe, been opened when Mr. Rutley visited the locality
more than 17 years ago.
The rock exposed in this quarry is in some respects an interesting
one. I collected three good specimens of it from different parte of
Digitized by Google
ToL 50.]
IGNEOUS ORIGIN 05 DARTMOOR.
301
the pit, and have examined thin slices of them under the micro-
scope*
No. 49 1101. 8p. Or. 202.
„ ftO 1100. „ 21*8.
„ 51 1009. „ 3D0.
These are grey-coloured compact rocks, showing blebby-looking
felspars sparsely scattered through them. Under the microscope
the rock is seen to be composed of augite, pscudomorphs of serpen-
tine, ilmenite, brown-red mica, sphcuc, apatite, a little secondary
quartz, and the remains of large porphyritic felspars in what was
probably a groundmass composed of felspathic material.
The augite, which is of a pale brown colour, is very fresh and, for
the most part, in idiomorphic crystals, though some of these are to
some extent corroded, internally and externally, by the base or
groundmass. Apatite is abundant, and ilmenite is still more so.
The latter has frequently been converted, in whole or in part, into
kucoxene, or into sphene. The mica is of a rich brown-red colour,
inclining to reddish yellow in thin leaves. The serpeutine appears
to be in part a pseudomorph after olivine and in part after augite.
In some cases its derivation from the former mineral seems clear,
for it is in rounded masses, or in six-sided and other fonns
characteristic of olivine. Sometimes the appearances under crossed
nicols indicate decidedly the original structure of that mineral.
The whole of the serpentine, however, cannot bo referred to
olivine. Some of it occurs in elongated or in large irregular
shapes : this is more suggestive of augite, or some other variety of
pyroxene ; and it is material to note that some of the unaltered
augite occurs in similar forms. Moreover, some of the serpentine
exhibits a series of parallel cleavages which naturally suggest the
pinacoidal cleavage of that mineral.
The large porphyritic crystals of felspar exhibit their original
crystallographic outlines very well, but the felspar itself has quite
disappeared, leaving behind opaque to translucent granular matter,
with inclusions of steutite and talc, which probably represent what
were originally endo-crystals of pyroxene enclosed iu the felspar.
Part of the original felspars have also been converted into an iso-
tropic colourless substance.
The groundmass has been changed into opaque to translucent
granular matter. I take it to have been originally a felspathic
groundmass, because the secondary granular matter into which it
has been changed seems to be the same as the granular matter in
the porphyritic crystals, and because in some cases the augites are
moulded upon what appear to have been lath-shaped prisms of
felspar radiating from the groundmass into the pyroxene.
This rock was, in its unaltered condition, a dolerite.
Mr. Kutley has shown in his memoir that the present hill of
Breut Tor is the ruin of an old volcano, and in figs. 7 and 8 of his
paper in the Quarterly Journal (vol. xxxvi. 1880, p. *Z\)'l) he
places the cone in the immediate vicinity of the existing hill, and
on its northern side. The position of the rock above described is
Digitized by Google
362
LIEUT.-GEN. C. A. MeMAH05 OS ROCKS OP [Aug. 1 894,
precisely that in which Mr. Rutley placed the throat of his volcano ;
and the rock itself would answer very well for a lava seething up in
this neck from below.
VI. Was Toe.
Immediately north of the Lydford Junction railway-stations, and
overhanging the G. W. Railway on its western side, is a little
hill marked Was Tor on the Ordnance map. As tho rocks exposed
here have not been described in Part II. of Mr. Rutley 's memoir,
or alluded to in Part I. of that work, and as Mr. R. N. Worth
in his * Geological Notes on the South- Western line between Lyd-
ford and Devonport,' also passes them over without notice, a short
description may be given here.
These rocks appear to be in the same line of outcrop as the
Bowdon-Longstone ' greenstone ' marked on the Geological Survey
map ; but the Bowdon 4 greenstone ' is represented as stopping
more than £ mile short of Was Tor.
I collected four specimens from the top of the Tor and two from
an old quarry on its north-eastern flank. A short description of
them is appended below : —
From Ou top of Was Tor.
No. 52 1108. Sp. Or. 268.
„ 53 1110. ,, 2-«tt.
„ 54 1109. „ 2-94.
„ 55 1111. „ 2 Mb.
From a quarry on the flank of Was Tor.
No.m 1112 Sp. Gr. 2 65.
,.57 1113. „ 2-68.
No. 52 is a highly carbonaceous shale, evidently one of the Culm
series. This locality is coloured ' Lower Culm Basement Beds,
Dolerites or Tuffs,' in Mr. Usshcr's Map I. in his * British Culm
Measures.' Under the microscope tho rock is seen to be made up of
grains of sand, intermingled with carbonaceous material and minute
flakes of mica. The carbon is arranged in wavy lines, and network
of lines, and the whole structure is clearly due to deposition in
water. The rock contains magnetite, but most of it has been dis-
solved out, leaving cube-shaped cavities. After the iron had been
removed with hydrochloric acid the carbon was easily driven off
by heat, the powdered rock becomiug quite colourless.
No. 53 is a fine-grained sedimentary rock of somewhat slaty type.
No. 54 is of altogether different character. It is a compact rock,'
something between sage-green and grey in colour. It has not the
smooth look or the unctuous feel of an ordinary serpentine, possess-
ing a fine granular structure and an appearance of roughness on the
fractured surface. In the field it would probably pass for an
ordinary compact lava : its hardness is 3*5.
Examined chemically the rock was found to be a hyd rated silicate of
iron and magnesia. It also contained alumina, but this was quite
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
363
subordinate to the magnesia. There was only the faintest possible
suspicion of lime. The acid solution reacted for titanic acid.
Under the microscope the base in transmitted light is of extremely
pale tint, and seems to vary from a yellow-green to a green-yellow,
and with high powers it is seen to be partly of obscurely fibrous
structure, and in part amorphous : it is isotropic. In this base there
are scattered patches and granules of doubly-refracting matter, which
appears to be in part quartz, and in part felspar.
The slice is profusely dotted over with filamentous threads, fibres,
and irregularly-shaped granules of leucoxene and magnetite or
ilmenite. The high specific gravity seem a due to the abundance of
the iron and leucoxene.
In a second and thicker slice which I have had made of No. 54,
and in No. 55 (a precisely similar rock), the original character of the
rock is better shown. It would seem to have been composed of a
network of small prisms (like the felspar-prisms in basalt), with
larger prisms scattered about in the groundmass. There are also
lacunoe which probably represent aggregations of pyroxene or
olivine. Some of them would do very well for the latter mineral.
In 55 the arrangement of the smaller dots of leucoxene suggests the
former presence of a glassy base.
I think that Nos. 54 and 55 were originally basaltic lavas, and
that they have been altered into a sort of serpentine. The shapes
of the prisms remain, but the substance of the felspar and augitv of
which they were originally composed has disappeared. The
resulting rock seems to be a variety of serpentine, which may be re-
garded as something between a normal serpentine and pseudophite.
In other words, I take it to be a variety of aluminous serpentine.
There may be some finely granular or finely fibrous chlorite
disseminated through Nos. 54 and 55, especially in the * lacuna),'
but it cannot be identified as such, and, if present, its fibres must be
so arranged as to produce compensation.
*
The beds on the top of the Tor, and those in the quarry below
dip N.N.E.
No. 56, which occurs on the top of the quarry, is a dark bluish-
black Carboniferous slate, weathering white, the surface of the
weathered portion being tinted an ochreous yellow. The dark
colour of the rock is due to the presence of carbon. Boiling in
hydrochloric acid does not remove the colouring, but on the applica-
tion of red heat the rock turns white. I have seen similar rocks
in this area weather white on the surface, and along cracks, where no
trap has been present, or, at any rate, where none has been visible.
No. 57, which crops out at the bottom of the quarry, under
No. 56, is a rhyolite. The hand-specimen might be taken for a
very fine-grained amygdaloid.
Under the microscope the groundmass is seen to be a glnss
showing fluxion-structure here and there, and sinuous streaking
due to lerrite-staining. In this groundmass are numerous rounded
and corroded crystals of quartz, and the remains of what were,
Digitized by Google
304 LIEUT.-GEH. C. A. M'MAHON OK BOCKS OP [Aug. 1 894,
apparently, more or leas rounded crystals of felspar. The felspars
have been converted into a soft white substance (pale buff-coloured
in transmitted light), which exhibits a feeble double refraction
between crossed niools : some of it has been partially replaced by
quartz. Between crossed nicols the ground mass breaks up into an
isotropic base ; in this occur doubly-refracting fibres and irregular
patchy aggregations of fibres, which are, I think, imperfectly
developed mica. Here and there are undoubted leaves of mica.
The slice also contains numerous granules of ferrite.
VII. Sun mart and Conclusion.
In the preceding pages I have noted the occurrence of felsite and
trachyte at Sourton Tors ; of rhyolite, and a variety of aluminous
serpentine, believed to have been derived from a basaltic rock, at
Was Tor ; and of a dolerite in the exact situation indicated by
Mr. Rutley as the probable position of the throat of the ancient Brent
Tor crater.
At Sourton Tors, and at Meldon, on the West Okement River, I
have recorded the occurrence of some interesting tuffs, the matrix
of which has been converted by contact-metamorphism into whet
closely resembles the base of a rhyolite, and which, in extreme
cases, exhibits fluxion-structure, or a structure indistinguishable
from it. So complete is the resemblance which this matrix assumes
to the base of an igneous rock that I was for long doubtful
whether the rock was not a lava full of volcanic ejectamenta ; but
the extreme abundance of the fragments — pieces of six or seven
different kinds of lava being sometimes visible in a single slice —
taken into consideration with the extended area over which these
deposits are to be found, convinced me that these beds are really
metamorphosed tuffs.
The occurrence of other interesting beds on the flank of Cock's
Tor, not noticed by previous observers, is also noted. These beds
now consist of a mixture of nearly colourless augite set in a base
which, in ordinary light, looks like a structureless glass, but which,
between crossed nicols, is seen to be made up of obscurely crystal-
line felspar. Many rocks reveal on their weathered surfaces the
secret of their primitive structure, and these bedB do so in a striking
manner ; their weathered surface exhibiting a corded appearance,
like corduroy cloth, that betrays, with a clearness that leaves little
room for doubt, the existence of an original lamination. Certain
appearances in Borne of the slides under the microscope confirm this
supposition, and I consider that the Cock's Tor rocks were originally
beds of fine-grained volcanic dust, which, in consequence of the
intense contact-metamorphism engendered by the great mans of
the Dartmoor granite, was converted iuto a mixture of augite and
1 els par.
In my first paper on tho Lizard schists I showed that the latter
contain numerous unaltered crystals of augite, and that the horn-
blende is a secondary mineral formed by aqueous agencies from the
augite ; in a joint paper written by Prof. Bonney and myself,
Digitized by Google
Vol. 50.]
IGNEOUS ORIGIN ON DARTMOOR.
3G5
we adhored to the idea suggested by De la Beche, and stated
that " the possibility of some portions of the Lizard schists having
resulted from the alteration of a stratified basic rock must not
be left out of sight." The evidence afforded by the Cock's Tor
beds appears to establish the correctness of this hypothesis by
revealing tho first stage in the series of changes that converted a
fine-grained ash into a hornblende-schist. The Cock's Tor and the
Lizard rocks, studied together, also show that the main agents which
effected the conversion of tho augite into hornblende were aqueous,
and that the lines of original lamination assisted the action of those
agents ; so that the alteration of the augite into hornblendo went
on hand in hand with the production of schistosity.
It only remains, in conclusion, to offer a few remarks on the
relations of the epidiorite and the volcanic rocks. Some former
writers have rather twitted De la Beche's Survey with having
mapped such rocks as the epidiorite and rocks of volcanic origin
(including ashes) under one wash of colour. But I am not sure
that De la Beche was so entirely wrong as his critics supposed. Thoir
criticisms were made under the impression that the rocks we now
call epidiorites solidified under plutonic conditions, and several
writers have called them gabbros. We know now that these rocks
are only altered dolerites ; and I do not think, from what I have seen
of them, that we need regard them as of very deep-seated origin.
There is no actual evidence in the area embraced in this paper
that the epidiorites are intrusive rocks. They certainly, in the
Sourton Tors and Meldon area, appear to conform to the bedding of
the ash- and lava-beds. I discovered no evidence of transgression in
their relation to the sedimentary rocks, and I think that their in-
trusive habit may, in many cases, have been assumed from their
supposed plutonic character. But even if they should ultimately
turn out to be intrusivo sheets, or sonietimes sheets or dykes, and
sometimes flows, I do not think this need necessarily divorce them
from the volcanic eruptions of that period. Flows, sheets, and dykes
are associated in almost every volcano ; and in studying under the
microscope samples of dykes and flows collected from the old crater-
walls of Somma I could not discover any material difference in their
structure. The epidiorites of tho West of Dartmoor may have been
comparatively deep-seated oflshoots of the volcanic forces that seem
to have opened up numerous volcanoes in this region during the
Carboniferous age. I regard the numerous volcanic rocks iu the
Tavistock-Okehampton area as the outcome of several small volca-
noes rather than of one large one.
Mr. J. G. Goodchild has shown in a recent paper1 that a holo-
crystalline structure may possibly be set up by contact-action in the
glassy magma of a lava, with the result that the rock assumes
" a plutonic instead of a volcanic facies." That factor must be borne
in mind in this region, where contact-metamorphism has been so
active ; but I do not think it necessary to fall back on that hypothesis
1 Geol. Mag. 189*, p. 24.
Q. J. G. S. No. 199. 2 0
Digitized by Google
ROCKS OF IGNEOUS ORIGIN OS DARTMOOR.
[Aug. 1894,
in the present case. Prof. Judd has shown, in his well-known
papers on the Western Isles of Scotland and on the ancient volcano
of ScLemnitz, that the igneous rock that was poured out at the
surface as a lava when " undergoing consolidation at some depth
from the surface assumed a most perfectly granitic character."1
And he states in another paper that "the distinction between
plutonic and volcanic rocks — however convenient and necessary it
may be in practice — is a purely arbitrary one, some lavas being more
highly crystalline than certain portions of intrusive masses." 3
In the present case, to confine myself to the area embraced in
this paper, I should say that the epidiorites are a long way short of
being hypogeno rooks (I have not found a particle of hypcrsthene or
diallago in any of them), and that there is nothing in their micro-
scopical structure to prevent them from being connected with the
volcanic activity of the Carboniferous age.
Discussion.
Mr. Rctlky considered that this paper would be of great value
not only to those geologists who had already worked in the Brent
Tor area, but also to those who might do so in the future. The
nugitic rocks described by the Author as occurring on the western
side of Cock's Tor, rocks which had hitherto been completely over-
looked, were of especial interest, and would have to bo taken into
consideration in the future mapping of the district. The discovery
by General McMahon of a dolerito at the spot which had been
indicated many years ago as the probable site of the original vent of
the Brent Tor volcano was, he hardly needed to gay, most gratifying to
him. He briefly explained the old diagrams used in the illustration
of his former paper, stating that one of the two faults, there indi-
cated as bounding the downthrown portion of the cone, was first
noted by the late Dr. Harvey B. Holl. A few remarks were also
made upon the schistose lavas and tuffs of the neighbourhood, and
on the great difficulty often experienced in assigning such rocks to
their respective groups.
Prof. Bonnet said that there were two points of great interest —
(1) the alteration of the trachytic ashes, which seemed to be some-
what abnormal, and (2) the conversion of a basic ash into something
like a hornblende-schist The latter was a most important contri-
bution to a very difficult subject. He was quite prepared to believe
that hornblende-schist might have this origin, though his work in
Bark had made him a little more doubtful than formerly about the
origin of the hornblende- schists of the Lizard.
Mr. W. W. Watts also spoko.
The Author, in reply, indicated the exact position of the Cook's
Tor beds, and thanked the fellows present for the kind and sym-
pathetic way in which they had received his paper.
1 Quart. Journ. Gcol. Soc. rol. xxxii. (1876) p. 323.
a Op. cit. vol. xIt. (1889) p. 191.
Digitized by Google
Vol. 50.]
FEELITIC CRICKS IX QUARTZ.
307
23. Note on the Occurrence of Perlitic Cracks in Quartz. By
W. W. Watts, Esq., M.A., F.G.S. (Communicated by per-
mission of the Director-General of the Geological Survey. — Read
March 21st, 1894.)
[Plate XVIII.]
Contents.
Page
I. Introduction 307
II. Macroscopical Characters 3o8
III. Microscopical Characters 308
IV. Perlitic Structure in Quart* 370
V. Conclusions 373
I. Introduction.
Since the publication of Mr. Allport's classical paper 1 on the
devitrified pitchstones of Shropshire, in which he drew some very
cautious deductions from the presence of perlitic and other structures
in rocks of felsifcic character, it has been customary to regard
perlitic cracks as an indication that the material in which they
occur has once been in a glassy condition. In 1893 I came across
a specimen (I 860), forming part of the old rock-collection of the
Irish Geological Survey, which raised grave doubts as to the safoty
of this wide generalization. It was obtained from Sandy Braes, in
Antrim, and was a specimen of the ' pearlstone * of Portlock.'4 When
cut it exhibited admirable perlitic structure, not only in the glassy
matrix of the rock, but also in the abundant porphyritic quartz-
crystals which it, contained.
Later on I found two specimens, collected by Mr. Rhodes, in the
English Survey collection (1 920, 927), which exhibited the same
characters, and one of them (1 927) was so well preserved as to
allow a thin slide to be made from it. It is this slide from which
the most satisfactory of the figures illustrating this paper have been
taken.
The specimens were obtained from the quarries at Sandy Braes,
1£ mile N.E. of Tardreo Mountain, in the northorn part of the
great rhyolite mass which is shown on Sheet 28 of the Geological
Survey map of Ireland. I have reason to believe that the descrip-
tion of the petrological characters and field relations of theso
rhyolites is in very good hands, so that I do not propose to give un
exhaustive description of the rocks ; it is sufficient for my purpose
to refer to the admirable descriptions of A. von Lasaulx.'
1 Quart. Journ. Geol. Soc. vol. xxiiii. (1877) p. 419.
3 * Report on the Geology of Londonderry,' 1843, p. 212.
3 Journ. Roy. Geol. Soc Ireland, Ber. ii. vol. ir. ( 1877; p. 227. and Ticher-
mak'» Min. u. Petrogr. MittheU. voL i. (1878) p. 410.
2c2
Digitized by Google
368
MR. W. W. WATTS OF THE OCCURRENCE [Aug. 1 894,
II. Microscopical Characters.
The ordinary type of Tardree rhyolite is well known ; it is a light
grey, or pinkish-grey, trachytic rock showing fair-sized crystals of
sanidine, smaller crystals of plagioclase, and some quartz, any ferro-
magnesian mineral being decidedly rare.
The variety from Sandy Braes, which I have more particularly to
describe, would be perhaps more appropriately termed a porphyritio
pitchstone (or obsidian), composed of a pitch-black glass, with a
lustre generally brightly vitreous, but occasionally more resinous.
The perlitic structure is clearly seen with a lens, and as the rock
fractures the projecting perlites stand out on its surface. Where tho
perlites are broken across the glass ib seen to become much paler,
and occasionally quite white towards their interior. Whilst the
felspars break along cleavage-planes, it is seen that the quartz,
instead of showing its customary conchoidal fracture, stands up in
rounded grains, and is traversed by cracks roughly concentric with
this outer surface. In some specimens there arc a good many patches
of a whitish substance, which may be devitrified glass. In specimen
1 927 large irregular cracks with wavy surfaces are seen to enclose
the perlites of the glass ; these are frequently coated with a thin
skin of haematite staining, and are the polygonal cracks to be after-
wards described.
From Connor, Sandy Braes, have come several interesting varieties
of the rhyolite, including the « pitchstone-porphyry ' of Portlock,
and amongst them a greyish-green variety (1861) with a horny-
looking groundmass and small porphyritic crystals. In the cracks
and cavities of this rock opal is not unfrcquently deposited, as seen in
the two specimens deposited in the Dublin Museum.
III. Microscopical Characters.
Von Lasaulx gives the following list of minerals as occurring in
tho Tardree rhyolites: — 4 Sanidine, clinoclase, tridy mite, quartz,
biotite, magnetite, epidote, apatite.' To this list I have only to add
the following : very rare pseudomorphs after hornblende, and minute
crystals of zircon and rutile.
These minerals are set in a brown translucent glass, sometimes
perfectly pure, but generally containing abundance of minute
trichites showing all the forms figured by Zirkel.1 Grains of
m.ignetite are also present, and minute microlites of felspar, which
are generally forked and frequently are mere skeletons built in a
negative crystal of glass. There is sometimes a very slight clearing
of tho matrix in the immediate neighbourhood of the magnetito.
Occasional patches with trachytic structure aro to be seen in the
1 Zeitachr. Deutoch. geol. Geselboh. yoI. xix. (ldG7)pl. xtii. figs. 8 and 14, and
pi. xir. fig. 2.
Digitized by Google
Vol. 50.]
OF PERLIT1C CRACKS IN QUARTZ.
309
glass, and sometimes these are surrounded by a few small felspar-
crystals accompanied by magnetite.
There is nothing unusual in the development of the perlitic
structure in the glass of these rocks. It is first traversed by two
sets of polygonal cracks, running very rudely at right angles to
one another, of which one set is generally much better developed
than the other. The cracks cross where they meet, and usually one
gives off a crack which curves round and joins the other tangen-
tially (PI. XVIII. fig. 2) ; inside the spaces thus formed come the
perlites, which vary from *05 in. to *0U5 in. in diameter. Some-
times they are simple, with circumferential cracks passing down to
a very small scale ; but very frequently one perlite contains several
others, like those figured by Allport 1 and the compound spheroids
figured by Bonney.3 Occasionally two perlites have one common
fiat side, aud, in one case that I observed, two perlites have impressed
a third which lies between them.
The cracks are usually filled up with a crystalline substance,
which depolarizes under crossed nicols and gives a maximum extinc-
tion in that part of the crack to which the short axis of one of the
nicols is tangential. This corresponds with several instances
described by Rutley and with the infilling of perlitic cracks in the
pitchstone (4 felsit-pechstein ') of Buschbad, near Meissen. In
consequence of this infilling the cracks are always best, and often
only, visible with crossed nicols ; indeed, prolonged observation with
high and low powers is necessary to appreciate the full perfection
of the contraction-structures in the rock. Generally there is a dust
of magnetite seen in those cracks which are oblique to the surface
of the section, and this, in one section, increases in quantity to such
an extent as to make the whole of the cracks black and opaque.
A very common feature is a close-set series of radial cracks which
run at right angles to the concentric cracks. These are very well
seen in PI. XVIII. figs. 1, 2, and 6, and though they are more usual
across the outer cracks of the perlite, they are by no means absent
from the inner and innermost cracks. They are not usually con-
tinuous for any considerable distance, but are replaced by othors
on different lines; and this is especially the case in opposite sides of
a perlitic crack. Similar fissures occur at right angles to the
polygonal cracks, as shown in PI. XVIII. figs. 2 and 3.
The contraction-cracks occasionally cause faulting in the flow-
structure. This latter structure is marked in several ways :— (1) by
light aud dark glassy bands ; (2) by darker glassy bands alternating
with lighter bands, which have a larger number of felspar-microlites,
or in which the groundmass is somewhat devitrified ; (3) by dark,
often twisted bands, in which there is an abundance of excessively
minute magnetite-dust ; (4) by stream-lines of dark trichites and
the general arrangement of them ; (5) by streams of felspar-
' Quart. Journ. Geol. 80c. vol. rxxiii. (1877) pi. xx. figs. 3 and 4.
9 Op. cU. vol. xxxii. (1876) p. 151, fig. 13.
Digitized by Google
370
PKULITIC CRACKS IN QUARTZ
[Aug. 1894.
microlites. Faulting in flow-structure of the third type is seen in
fig. 1, p. 371.
Occasionally perlitic cracks may be seen to traverse the trichites
(as in the slide from -which fig. 1 is taken), and at other times a
similar fissure may be seen passing through a felspar-microlite.
These phenomena are, however, difficult to observe, and are not likely
to be common, because the perlitic cracks circle round the edge of
the phenocrysts and the flow-structure determines the microlites to
take a similar direction. It would be impossible to tell whether a
crack, usually more or less oblique to the section, cut through the
breadth of such minute microlites. The depolarizing granules are
similarly seen to be cut through, without displacement, by the
cracks.
A curious feature of the matrix-perlites is the frequent bleaching
of their interior. The colourless centres are not as a rule devitritied,
although this may sometimes occur ; generally they are made
up simply of a colourless glass, which passes gradually into the
normal brown glass, and then, very occasionally, in the centre there
is a group of fairly developed felspar-microlites. Inside a few of
the colourless perlites the glass has been broken up by a number of
irregular star-like fissures. In extremely few instances the very
centre of the perlite is darker than the rest, and then there is a
slight aggregation of trichites at that spot.
There is no optical evidence of strain in the perlites. Where the
flow-structure is pronounced and of type 2 the perlites may occur
only, or more frequently and with greater perfection, in the glass ;
or they may cut both the glass and the lithoidal portion ; or, in still
rarer cases, a single perlite will involve both structures, but its cracks
will not be so clearly visible where they cross the lithoidal baud.
IV. Perlitic Structure in Quartz.
In many of the rounded porphyritic crystals of quartz in this
rock very fair examples of perlitic structure are to be seen, which are
at least as perfect as those produced by the rapid cooling of Canada
balsam. Indeed, I am able to show that not only are these cracks
of a general perlitic nature, but that (1) the cracks pass outwards
from crystals to matrix ; (2) the matrix-perlites are sometimes com-
pleted in the quartz ; (3) perlites are formed in quartz and completed
in the matrix outside ; (4) the polygonal cracks sometimes extend
into the quartz and have the same characters as in the matrix ;
(0) the radial cracks are also to be found in the quartz, and even
enter the quartz from the matrix.
The general nature of the perlitic cracks in the quartz can be
judged by reference to the figures. Tho most characteristic is,
perhaps, that shown in fig. 2, where the inner crack is very perfect,
and two outer cracks arc connected with it by radial fissures. The
same characters are seen in PI. XVIII. fig. 4, in which the whole of
the quartz is traversed by a series of curved cracks of a general
Digitized by Google
Fig. 1. x 25.
Continuity of cracks in quartz and matrix.
Faulting of flow-structure by cracks ;
trichitea in brown glass (I 927).
Fig. 3. x 25.
Concentric cracks in quartz ; flow- Cracks of perlitic type in quartz ;
structure in matrix (I 860). perlite in glass inclusion (1 800).
Fig. 5. x 25. Fig. 6. x 25.
Digitized by Google
372
MB. W. W. WATTS ON TUB OCCUBRENCB [Aug. 1 894,
perlitic aspect, which are clearly the result of contraction. Of these,
one at the top passes from the quartz into the matrix, and then hack
again into the quartz.
Similar features, with some amount of variation, are visible in
fi£3. 3 and 4 (p. 371 ), in both of which one or other of the cracks may
be seen to traverse the matrix for part of its course. Inside a quartz-
grain in fig. 4 there are perlitic cracks in a glass inclusion, while in
another quartz from the same slide there is a tendency for the
cracks to aggregate in the neighbourhood of a matrix inclusion.
Slide 1 926 displays the difference in the behaviour of quartz and
felspar under the cooling strain, the only cracks visible in the latter
being those due to cleavage, while the practical absence of cleavage
in quartz allows of the formation of spherical cracks. In PI. XVIII.
fig. 3 will be seen excellent polygonal cracks in quartz and matrix,
with imperfect perlites in both substances.
It might have been supposed that the independent contraction of
the quartz was responsible for the perlitic structure, and that it
was quite apart from the generation of perlites in the matrix. A
minute inspection of these figures will, however, show that occa-
sionally some one crack or other penetrates from the quartz into the
matrix, and may even return into the quartz ; and an examination
of the thinnest slice with very high powers shows many clear cases
to prove that the glass and quartz must have shrunk and cracked
together.
Fig. 1 represents a portion of the slide 1927 drawn with a 1-
inch objective, but with the details put in from a £-inch. It is
perfectly clear that the quartz is perlitic, and that there are at least
four, and probably two more, cases of continuity of crack from
quartz to matrix. There is generally a slight deviation in direction
when a crack passes from one substance to the other ; but this is
very small, and the main trend of the crack is preserved. The
drawing also represents diagrammatical!)' the wisps and curls of the
trichites and the deposit on the cracks, while it rouses a suspicion
that the cracks have slightly faulted the edgo of the quartz.
A more important case is presented in fig. 5 (p. 371), where the
quartz is the focus of the perlite and is traversed by t wo of its cracks,
at least one of which is continued for two thirds of the distance round
the crystal in the matrix, although the actual continuity is obscured
by a slipping of the section during grinding. Somewhat similar and
perhaps clearer relations are displayed by fig. 6 (p. 371 ), in which the
quartz is again at the centre of the glass-perlite and is surrounded
by a crack which encroaches on the border of a neighbouring quartz-
crystal; while in PI. XVIII. fig. 2 a crystal of quartz is cut by two
perlitic cracks, each of which traverses the matrix as well, both
being included in a single circular crack, which does not touch the
quartz. In PI. XVIII. fig. 1, again, the quartz is the focus of a
perlite which is completed in the matrix ; fig. 1 a shows the outline
of the quartz in this figure.
Two more important cases remain for description. In PI. XVIII.
Digitized by Google
Vol. 50.]
OF rERLITIC CRACKS IS QUARTZ.
373
fig. 5 a large matrix-perlite is seen bordering a second, which has
a perfect set of radial fissures. The outer crack of the first perlite,
which goes off at a tangent, enters tho quartz-crystal in the lower
part of the figure, traverses it for a short distance, and then passes
out into the matrix. The angle made by this crack with the average
circumference of the perlite is not greater than that of its inner
cracks where traversing the matrix only. A couple of radial
fissures are given off by it, and, further, there is a set of polygonal
cracks surrounding the principal perlite, with branch cracks sur-
rounding subordinate ones ; of these, two major cracks and one of a
minor character occur and join up in the quartz. PI. XVIII. fig. 0
gives an excellent examplo of a typical matrix-perlite contained in
polygonal cracks, and giving off a great number of radial fissures.
Some of the polygonal cracks are confined to the matrix, others just
traverse the quartz, and radial cracks passing from the perlitic
cracks of the matrix are seen to pass into the quartz and stop there
at the junction with the polygonal crack (see PI. XVIII. fig. 6 a).
When traversing quartz the cracks are generally filled with a
deposit, sometimes of magnetite, generally associated with small
granules or plates, probably of specular iron, and usually also
with a deposit of a colourless mineral, which is likely to be quartz.
A curious reticulated structure is seen in the latter, with which
also a little chlorite occurs.
I have reserved till last the occurrence of the cracks in slide 1 861,
cut from the lithoidal variety referred to on p. 368. The matrix
is traversed only by polygonal cracks, amongst which it is very rare
to find anything approaching a perlite ; indeed, 1 have only seen
one in the slide. The matrix is not glassy, but consists of recog-
nizable microlites of felspar (varying from -001 to '004 in. in
length), often forked, and set in a cryptocrystalline granular sub-
stance. Immediately round the quartz, perlitic cracks are very
frequent, but they very rarely avoid the quartz altogether ; the
large polygonal cracks of the matrix, however, in most cases avoid
the quartz, passing round the crystals or being deflected very con-
siderably before entering them. On reaching the felspars these
polygonal cracks generally pass obliquely through them, stepping
down along the cleavage planes. In the matrix cracks may some-
times be seen, though rarely for the reason given above, to cut
and traverse felspar-microlites — making it quite certain that the
lithoidal structure existed before the perlitic cracking, and that the
matrix is in all probability original and not a devitrified glass.
V. Conclusions.
The facts recorded above allow us to draw the following deduc-
tions : —
1. That perlitic cracking is not inconsistent with crystalline
structure, but is only likely to be developed where there is no good
cleavage along which the strain would be more easily relieved.
Digitized by Google
374
MR. W. W. WATTS 05 THE OCCURRENCE [Aug. 1894,
2. That the cracking in the crystals has taken place after the rock
became solid, as proved by the passage of cracks across the inlets of
matrix occurring in the crystals, and, indeed, cutting across every
constituent and structure of the rock, quartz, glass, felspar, micro-
lit* s, trichites, and flow-structure.
3. That it is subsequent to the development of lithoidal structure.
4. That the occurreuce of perlitic structure cannot be safely
relied upon to prove that the rock has ever been in a glassy con-
dition, but that the lithoidal matrix is in certain cases original.
5. That the glass of the rock has probably about the same
coefficient of expansion and contraction as the quartz, but not quite,
as there is always a little deflection in the cracks at the junction, and
always a tendency for them to bifurcate at the edge of the quartz ;
but that in the case of lithoidal (trachytic) structure there is
probably a considerable difference.
This is not the first time that the occurrence of perlitic cracks in
crystals has been described, although the chief instances have not
attracted much attention in England. MM. Fouque and Levy 1 in
1&73 referred to two or three instances known to them : — 44 Dans
le groupe des porphyron quartziferes nous trouvons la roche do Per-
seigne, pros d'Alencon, qui presentedes fissures spheriques dcveloppees
autour et memo au travers des grands cristaux ;" and again, speaking
of the homblende-andesites of the region south of Santorin, " Les
fentes do retrait traversent les grands cristaux."
Mr. Kutley, in his paper on the vitreous rocks of Montana,3 says,
" In the section to which our attention is now confined there are
plentiful examples of doubly-refracting crystals which are imme-
diately surrounded by perlitic cracks, but which do not, save very
exceptionally, transgress those boundaries ; " and again, " In those
few instances in which a perlitic crack passes through a crystal, there
is commonly another crystal doveloped by its side (p. 397).w
The circular cracks seen in olivine have often arrested the present
writer's attention, and a description of them by Prof. J. P. Iddings,
noting the likeness to perlitic structure, will be found in 4 The
Geology of the Eureka District, Nevada ' (1892), Appendix B,
pp. 387, 388, and pi. iii. fig. 11, Monographs of the U.S. Geol.
Survey, vol. xx.
Slight traces of similar perlitic structures have been noticed in the
pitchstones of Donegal and Newry, and also in the porphyritic
crystals in some of the igneous rocks of Charnwood.
These instances would have rendered unnecessary any description
of the specimen from Sandy Braes; but the chain of structures and
evidence seemed so complete as to merit a detailed description.
1 Cotnpte« Rendus Acad. Sci. toI. IxxxyL (1878) p. 771.
a Quart. Jouru. Geol. Hoc. vol. xxxyu. (18*31) p. 391.
Digitized by Google
Vol. 50.]
OF PERLITIC CRACKS IN QUARTZ.
375
EXPLANATION OF PLATE XVIII.
All the specimens are from Sandy Braes, 1$ niile N.E. of Tardree Moun-
tain. Antrim. The numbers refer to the apnea of sliced rocks in the col-
lections of the Geological Surrey of Ireland.
Fig. 1.1927 a. Polygonal and radial cracks in matrix of pitchstone. Perlite
centred in quartz and involving matrix. X 25.
Fig. 1 a. Outline of quartz in fig. 1 .
Fig. 2. 1927 a. Radial crack* from polygonal and perlitic cracks. Matrix-
perlitc, enclosing two perlites which involve quartz uud
mAfrix. X 25.
Fig. 3. 1 927 a. Polygonal aud spherical cracks in quartz and matrix, x a *
Fig. 4. I 927 A. Spherical cracks in quartz, some of which pass into the matrix.
The cracks are filled with a brown deposit, showing reticu-
lated texture. X 25.
Fig. 5. 1 927. Matrix-porlite, with outer and polygonal cracks traversing
quartz. X 25.
Fig. 0. 1 927. Matrix-perlite, with radial cracks ; polygonal and radial cracka
traversing both quartz and matrix, x 25.
Fig. 6a. Radial cracks at junction of quartz and matrix. X 125.
Sote.— The drawing of each illustration in this paper has been carefully checked
by photographs taken on the same or a larger scale.
Discussion.
Mr. Rutlet remarked that tho careful observations made by the
Author appeared to be quite satisfactory up to a certain point,
although he should hesitate to describe tho cracks in the quartz
aud olivine-crystais as perlitic. That perlitic structure and tho
structures seen in these crystals were both due to shrinkage there
was no question. Spheroidal structure in basalts and other crys-
talline rocks also resulted from tho same cause, yet the spheroidal
structure of a basalt and the perlitic structure of an obsidian were
sufficiently different to deserve different names. He had occasionally
met with cracks in olivine-crysUls similar to those exhibited, but ho
had never regarded them as perlitic. On the whole, he considered
that the Author had given the Society an extremely interesting and
valuable paper, but he did not agree with him in thinking that the
facts now brought forward were sufficient to invalidate conclusions
hitherto formed with regard to tho once vitreous character of rocks
showing perlitic structure. In the absence of this structure it was
not possible to say whether a felaite origiually solidified as a lithoidal
or as a vitreous rock, because, if originally vitreous, it might assume
a lithoidal character through devitrification. Furthermore, if
perlitic structure occurred in a lithoidal rhyolite, there was no means
of proving that the rock was lithoidal when the perlitic structure
was developed.
Mr. Harker thought the Author had proved that true perlitic
cracks may be formed in a mineral like quartz, possessing no marked
cleavage. Ue compared the phenomena with those recorded in tho
Digitized by Google
376
FERL1TIC CRACKS IN QUARTZ — DISCUSSION.
[Aug. 1894,
Meissen pitchstono. There, according to Sauer, the generally peri-
pheral arrangement of the cracks within the quartz-crystals indi-
cated a greater contraction in the mineral than in the surrounding
glass. In the rock now descrihed, the frequent continuity of the
cracks through glass and crystal alike pointed to a smaller difference
between their respective coefficients of contraction.
Prof. J. F. Blake also spoke.
The Author, in reply to Mr. Rutley and Prof. Blake, pointed out
that the perlitcs in quartz were of the same nature as those in the
surrounding glass, that the two substances were ofteu involved in
the Bamc perlite, but that the quartz cracks were often quite inde-
pendent and frequently concentric. As the cracks traversed every
structure in the rhyolites, including triehites and mierolites, he felt
no doubt that the felsitic structure was in this case original.
Digitized by Google
Vol. 50.]
ORIGIN OF NOT AC U LIT 139 \ND QUA RTZITE9.
377
24. On the Origin of certain Novaculites and Quartzites. By
Frank Rutley, Esq., F.G.S., Lecturer on Mineralogy in the
Royal College of Science, London. (Read March 21st, 1894.)
[Abridged.]
[Plats XIX]
Although various explanations have been offered regarding the
origin of certain novaculites it seems that more may yet be said
upon this subject. A useful resume of the opinions held by different
authors is given in the ' Annual Report of the Geological Survey of
Arkansas for 1890,' 1 by Mr. L. S. Griswold. Before attempting
to explain my own views it seems desirable that I should allude
briefly to the specimons upon which those viows are based, and
especially to the Arkansas novaculites, since Mr. Griswold's intimate
acquaintance with these rocks, both in the field and in the labora-
tory, lends great weight to his opinions. Indeed, it may seem
presumptuous on my part to question them, since I have no know-
ledge of tho ground with which he is so familiar, and also because
the material at my disposal consisted of two small specimens, while
he has had mountain-ranges to work upon.
The specimen of Arkansas stone which I have examined is a
bluish-white rock with a faint yellowish tinge, translucent in
moderately thick splinters, breaking with a conchoidal to splintery
fracture and bearing a general resemblance to chalcedony. The
structure is cryptocrystalline, and it shows under the microseopo
the outlines of what were once cavities of rhombohedral form, now
occupied by siliceous deposits of secondary origin.2 The specimen
of Ouachita 8 stone resembles a faintly yellowish-white or cream-
coloured biscuit-porcelain, except that it exhibits barely a trace of
translucency on thin edges.
Under the microscope this rock is also seen to possess a crypto-
crystalline structure, but of somewhat coarser texture than that of
the Arkansas stone. It likewise shows numerous little cavities,
some of which have irregular boundaries, but a large proportion of
them have the form of rhombs and represent cavities once occu-
pied by crystals of a rhombohedral carbonate (PL XIX. fig. 3).
The siliceous grains which form the walls of these cavities often
show a regular arraugement, like a course of masonry (PL XIX.
fig. 3) ; but beyond those borders the arrangement of the siliceous
1 Vol. iii. ' Whetstones and tho Novaculites of Arkansas.' I am greatly in-
debted to Mr. W. Topley, P.R.S., for calling my attention to this admirable
work, and also for the loan of the book.
1 Tbis specimen appears to correspond with that described as ' Slide No. 31 '
of Mr. OrU wold's series. Op. eit. p. 13T».
1 Usually spelt 4 Washita ' in this country. I adopt Mr. Griswold's spelling
as doubtless the more correct.
Digitized by Google
378
MR. F. RUTLF.Y ON THE ORIGIN OP
[Aug. 1S94,
grains is confused and quite irregular, just as one finds it in ordinary
cases of cryptocrystalline structure.1
These general characters seem to agree perfectly well with the
descriptions given by Mr. Griswold, who usually speaks of the
rhombohedral cavities as having been occupied by calcite. On
p. 188 of his work, however, he says that 44 the rhombohedral cavities
undoubtedly contained crystals of calcite or dolomite."
Without entering at present upon the question whether the silica
of the Arkansas and Ouachita stones is to be regarded as quartz <>r
as chalcedony, but accepting for the moment Mr. Oris wold's con-
clusion that it is the former, it will be best to quote some of the
passages in his book which refer more especially to the origin of
these rocks. Evidently he has felt it important to compare them
with chert, and the following extract from his work,2 headed
4 Differences between Novaculite and Chert,' is therefore given in
full:—
44 Defining chert according to the weight of opinion as a crypto-
crystalline siliceous rock formed by chemical action, and containing
a large percentage of the silica in the chalcedonic form, it is now
possible to state wherein the Arkansas novaculites differ from chert,
and to present the theory of their origin. Chemical analyses tend
to show that the novaculites of Arkansas have a purer siliceous
composition than cherts, though if the calcite had not been dissolved
from the Ouachita stone it could not have been distinguished from
chert. The tests of solubility of the silica show a decided difference
between novaculite and chert. Microscopic examination showB that
the soluble silica of chert is in the form of chalcedony, while novacu-
lite is entirely without silica in this form.
44 As a result, apparently, of this difference in the form of silica,
novaculite has a fine gritty feeling, while chert is more glassy.
Owing also to the purer and more homogeneous composition of
novaculite, this stone is more translucent than chert. Novaculite is
not a tough rock like chert, and breaks more easily, though its
conchoidal fracture is as perfect as that of any chert or flint."
With reference to Arkansas stone, there is one fact which seems
to me to be of considerable importance, namely, that, under the
microscope, the structure of Arkansas stone very closely resembles
that of flint, in those portions of the latter which are free from
organic remains (PI. XIX. figs. 1 & 2). So close is this resem-
blance that when such a section of flint has been examined in
polarized light, between crossed nicols, and a section of Arkansas
stone is immediately substituted, no difference can be recognized
between the two sections. One may, indeed, say that Arkansas
stone and flint are practically identical in structure. The structure
of Ouachita stone is similar, but somewhat coarser in texture.
1 For these and for other specimen* of hone-stones I am indebted to my
friend Mr. Wm. Berrell, M.I.C.E., who procured them from Mr. T. liazeou, of
10, Bi»hop*gate Avenue, E.C., the importer.
2 Op. cit. p. 187.
Digitized by Google
Vol. 50.]
CERTAIN XOVACULITKS AND QTTA11TZITKS.
379
The employment of a Klein's plate does not, in the case either of
Arkansas or Ouachita stone, appear to indicate the presence of any
appreciable amount of amorphous silica. Even in flint the close
examination of single minute areas during a complete revolution
discloses a change of tint in the Klein's plate, and it therefore
appears that, at all events for the most part, the component particles
of flint are doubly refracting.
So far as the presence of soluble silica in cherts is concerned, the
researches of Prof. Renard 1 indicate that in those of the Carboni-
ferous Limestone of Belgium the amount is extremely small. More-
over, the analysis, by Mr. £. T. Hardman, of one of the purest
specimens of Irish chert examined by him gave 95-50 per cent, of
insoluble silica, while only a trace of soluble silica was present.*
On treating a thin translucent splinter of Arkansas stone with
fuchsine no appreciable staining was visible under the microscope.
Without here questioning the opinions expressed by Mr. GriewoH,
which appear to be borne out by tho analyses given by him, it
appears to me strange that, although he notes the close resemblance
of some of the Arkansas stone to chalcedony, he says nothing about
the extremely close resemblance in microscopic structure between
it and flint.
Prof. J. D. Dana deflnes flint as " somewhat allied to chalcedony,
but more opaque," and with regard to the silica of which it is corn-
composed, he adds that it, " according to Fuchs, is partly soluble
silica." 3 Prof. Tschermak observes that it contains some opal sul>-
stance, due to organisms.4 Prof. A. de Lapparent, after alluding to
the fibrous structure of chalcedony, as seen under the microscope,
adds : " when chalcedony becomes very compact, with a more and
more confused orientation, it passes into flint.'' 5 Finally, we have
the researches of MM. Michel-Levy and Munier Chalmas,6 in which
more exact methods of determining chalcedony and other forms of
silica are employed, but in cases such as those which we are now
considering no satisfactory results could be arrived at, so far as the
determination of optical characters is concerned — one difficulty being
that we are not dealing with fibres, but with granules of microscopic
dimensions and of most irregular forms, so that there is no crystallo-
graphic direction of elongation upon which to base observations.
I have attempted to determine the optical sign in the apparent
direction of elongution of some of the larger siliceous grains forming
the border of a rhombohedral cavity in Ouachita stone, with the
result that only alternate grains give a rise, while the intermediate
produce a fall in the colour-scale when a quartz-wedge is employed.
' ' Rccberehes lithologiques sur lea Phthanites da Calcaire Carbonifere de
Belgique,' Bull. Acad. roy. Belgique, ser. 2, vol. xlvi. (1878) p. 494.
1 • The Chemical Composition of Chert, and the Chemistry of the Process by
which it is Formed.' Sci. Trans. Roy. Dublin Soc. vol. i. (new aerie*) p. 90.
3 • 8vstem of Mineralogy,' 6th ed. 1892, p. 189.
4 4 Lehrbuch d. Mineralogie,' 3rd ed. 1883, p. 388.
• • Cours de Mineralogie, 1884, p. 340.
fl * Memoire sur diverse* Formes affectoes par le Reaeau Elementaire du
Quart*,' Bull. Soc Min. France, vol. xv. (1892) p. 159.
•
1
Digitized by Google
380
MR. F. RUTLEY OX THE ORIGIN OF
[Aug. 1894,
Id other cases in the same section I have obtained quite irregular
results. Such differences are doubtless due to differences in the
orientation of grains of the same character.
As already mentioned, little if any distinction can be made be-
tween the most chalcedony-like variety of Arkansas stone and those
portions of a flint which exhibit no traces of fossil organisms.
From this extreme it seems probable that gradations may be traced
to coarser structural conditions, in which Ouachita stone represents
an intermediate and quartzite an extreme phase of coarseness.
This is partially shown on PI. XIX. figs. 1, 7, & 8. Fig. 7
represents the thin edge of a section of a pebble from a conglomerate
from Purtiall, in the Deccan. Except on the margin, this section
exhibits what may be termed a cryptocrystalline structure on a
large scale, while on the margin it shows a microcrystalline struc-
ture on a large scale, as in fig. 7. In this case the cryptocrystalline
aspect is evidently due to the overlapping of crystals, while on the
margin the section is only thick enough to include a film of juxta-
posed, but not superposed, crystals. Fig. 8 is drawn from a section
of a quartzite from Nondweni, Zululand, and represents what we
may, for the timo being, regard as the extreme phase of coarseness
in this series.
I speak of these rocks as constituting a series, because I believe
that they have all had a common origin, that they are all siliceous
replacements of limestones. It is a generally recognized and, I
think, an incontrovertible fact that a large proportion of quartzites
are more or less altered sandstones, as clearly demonstrated by
Irving and Van Hise.1
The former of these authors, when speaking of the genesis of the
Huronian quartzites, stated that "all the true quartzites of the
Huronian are merely sandstones which have received various degrees
of induration by the interstitial deposition of a siliceous cement,
which has generally taken the form of enlargements of the original
quartz-particles, less commonly of minute independently oriented
areas, and still less commonly of chalcedonic or amorphous silica : two,
or even all, of the three forms occurring at times in the same rock.*' 4
Fully admitting the truth of this statement, which deals only
with 4 true quartzite*,' I am, nevertheless, inclined to think that it
is needful, not on mineralogical, but on genetic grounds, to divide
tho rocks which might be generally termed 4 quartzites ' into two
groups, including in the one group the indurated sandstones or true
quartzites, which might, for the sake of distinction, be termed
4 detrital quartzites ' ; in the other siliceous replacements of lime-
stones which, at times, may simulate detrital quartzites both in
mineralogical and structural characters. These might bo termed
4 infiltration or mctasomatic quartzites.'
The necessity for such a classification I hope to render more
apparent by dealing at some length with the rhombohedral cavities
1 'On Secondary Enlargements of Mineral Fragment* in certain Beck*/
Bull. U.S. Geol. Surv. So. 6, vol. ii. (1884). » Rid. p. 48.
Digitized by Google
Vol. 50.]
CERTAIN NOVACCLTTES AND QUARTZTTES.
381
and inclusions in certain siliceous rocks to which the name 'quartzite*
is applied by some authors, and ' chert ' by others.
Some of the cherts dorived from the Carboniferous Limestone of
Belgium, and described by Prof. Reuard, contain rhombohedral
crystals which, although very minute, give distinct reactions for
magnesia, and these Prof. Benard regards, apparently with good
reason, as crystals of dolomite.
In a section of a pebble from the conglomerate of Purtiall, in the
Deccan, I have noticed the occurrence of similar rhombohedral
crystals. Portion of a section of this pebble is represented in
PI. XIX. fig. 4, as seen between crossed nicols. The polarization-
picture afforded by the quartz in this part of the section is suggestive,
as I have already stated, of a cryptocrystalline structure, but the
marginal portions of the soction give distinct proof that the rock
consists of small crystals of quartz and, could the preparation be
rendered as thin in all parts as it is on the margin, it would doubt-
less appear, in polarized light, as a uniform mosaic of distinctly
individualized quartz-crystals. One of those on the margin, repre-
sented in PL XIX. fig. 7, gave a positive uniaxial interference-
figure.
The occurrence of small rhombohedral crystals of dolomite in " a
flinty, grey or dark-grey jaspilyte from, the shaft at the Breitung
mine," Minnesota, has been pointed out and figured by Prof. N. H.
Wine-hell.'
It has been considered doubtful whether the cavities in the
Arkansas novaculites were originally occupied by calcite or dolomite.
If these rocks represent the replacement of limestone by silica, it
may, I think, be assumed with good reason that the limestone so
replaced was either a dolomite or a dolomitic limestone.
There seems nothing uureasonable in such a supposition, since
dolomites of Archaean age are known, and Huronian dolomitos and
dolomitic limestones occur in Michigan.3
Let us, in the first case, suppose the replaced rock to have been a
dolomite. It is well known that dolomites consist, as a rule, of
minute rhombohedra. A section cut from a specimen collected at
Matlock, from one of the magneaian limestone-beds which there
constitute part of the Carboniferous Limestone system, consists
almost entirely of such small rhombohedra (PL XIX. fig. 5). An
analysis which I made of this specimen showed it to be almost
identical in composition with the typical dolomites of the Magnesian
Limestone series, the calcium carbonate amounting to 51*25 and the
magnesium carbonate to 42 18 per cent., the remainder consisting
mainly of silica, with a little iron, alumina, and water. A small
fragment of this specimen, whrn placed in dilute hydrochloric acid,
let fall a fine granular deposit, the grains falling from the fragment
1 ' The Iron Ores of Minnesota,' Geol. & Nut. Hist. Suit. Minn. Bulletin
no. 6 (1891) p. 77, and pi. Tin.
3 Credner, * Elemente d. Geologie,' 3rd ed. 1876, p. 37a
Q. J. G. & No. 190. 2 d
Digitized by Google
382
MR. F. EUTLEY OS THE ORIGIN OF
[Aug. 1894,
as the acid dissolved and disintegrated it. The deposit, when
examined under the microscope, was found to consist of minute
rhombohedra, some of which were considerably, and others slightly
eroded, while many exhibited perfectly sharp angles and edges
(PI. XIX. fig. 6).
It seems quite possible that such a limestone might, through
natural causes, become almost wholly dissolved and replaced by
Bilica, the replacement going on gradually and keeping pace with
the dissolution of the limestone, a rhombohedron becoming here
and there enclosed in the siliceous matter and thus protected from
further erosion. That such was the case in the Ouachita stone
is reudered extremely probable, from the fact that many of the
cavities have irregular boundaries, such as would have resulted Irom
the enclosure of partially eroded rhombohedra or small groups of
rhombohedra. In PI. XIX., figs. 9 & 10, two such cavities are
shown. Sometimes cavities occur which have evidently been occupied
by a group of ten or twelve coherent crystals. I think it must be
admitted that the forms of these cavities give evidence of erosion,
rather than of arrested crystallization of the mineral which once
filled them.
In the next place, let us assume that the original limestone was
not a true dolomite, but merely a dolomitic limestone. Then, since
calcite is more readily soluble than dolomite, it is easy to imagine
that the whole of the calcite might become dissolvod and replaced
by silica, the latter enveloping the less readily soluble rhombohedra
of dolomite. If a small amount of limestone can be replaced by
silica, as in the layers and nodular bands of chert, met with in the
Carboniferous Limestone, there seems no reason why, given a sufficient
supply of silica in solution, thick beds of limestone should not be
wholly replaced.
That it is unsafe to deny, in all cases, a detrital origin to siliceous
beds associated with limestones is rendered sufficiently evident from
the occurrence of thin beds of metamorphosed sandstone or quartzite
interetratined with limestone at Modoc Peak in the Eureka district.
This sandstone is described by Prof. Iddings as somewhat micaceous
aud graduating from an extremely fine-grained to a coarse-grained
rock " having the mineral composition and structure of a micro-
granite." 1 Judging from the figure given in his memoir, which re-
presents a section magnified 33 diameters, the rock is a quartzite,
or, as it is described, a quartz-conglomerate, of somewhat coarse
texture and in no way resembling siliceous rocks of cryptocrystalline
character, such as Arkansas stone, Ouachita stone, flint, or chert,
none of which exhibit characters which a sandstone even of the
most altered typo would possess. The Modoc Teak quartzite, on
the other hand, consists of rounded grains of quartz cemented by a
secondary deposit of silica, and is unquestionably a sedimentary rock.
1 « Geology of the Eureka District, Nevada,' by Arnold Hague, Monograph*
U.S. Geol. Surv. vol xx. (1892), Appendix B, by J. P. Iddmga, p. 346, and
fig. 3, pL iv.
Digitized by Google
Vol. 50.] CERTAIN NOVACULITES AND QUABTZITE8. 383
Reverting once more to the rhombohedral cavities which occur in
Ouachita stone, there seems to he an additional reason for believing
that they were originally occupied by dolomite and not by calcite,
from the fact that the rhombohedron, when uncombined with other
forms, is not common in calcite, while it is of extremely common
occurrence in dolomite.
The general absence of fossils in the actual novaculites of
Arkansas, although some, chiefly the ossicles of crinoid-stems, have
been met with,1 need form no barrier to the hypothesis that the
rock is a siliceous replacement of a limestone, since it is common to
find beds of dolomite almost or quite destitute of fossils, and, as
Prof. Renard remarks, 44 gelatinous silica moulds itself upon objects
and preserves their forms ; dolomite, on the contrary, through its
tendency to develop terminated crystals, tends to efface them when
it becomes infiltered among organic remains/' 2 Furthermore, the
stratigraphical relations of the Arkansas novaculites are not incom-
patible with the assumption that they are the siliceous replacements
of limestone ; for, according to Mr. Griswold, they occur between
shales of late Lower Silurian ' (Ordovician) age in which graptolites
are found, including the genera Diployraptus and Dicranoyraptus,
both of which are abundant in the Bala series of Wales, while the
former genus, if not the latter, occurs also in the black graptolitic
shales of the Coniston Limestone series.
The association of the Arkansas novaculites with black grapto-
litic shales, and that of our own Ordovician limestones with similarly
coloured graptolitic shales, is not, certainly, a proof that the nova-
culites are representatives of Ordovician limestones, but it is a
coincidence which, to say the least, is significant.
At this stage it seems desirable to discuss the character of the
siliceous grains which constitute the Arkansas novaculites.
In a paper by Messrs. A. J. Jukes-Browne and W. Hill * remarks
by Dr. G. J. Hinde are quoted, in which he says that ho " is unable
to explain the causes which havo produced this singular [globular]
form of colloid silica, or to say why the silica of the sponge-
spicules should not have passed into the more stable condition of
chalcedony or crystalline quartz, as is the case with those of most
other fossil sponge-beds." Here wo have Dr. Hindo's statement
that sponge-spiculcs may be found not only in the condition of
colloid silica (opal), but also in the cryptocrystalline condition
(chalcedony) and in the crystallized condition (quartz). This appears
to indicate that the originally colloid silica of a sponge-spicale may
undergo a series of changes which culminate in its conversion into
quartz. May not that which happens in a sponge-spicule also
occur in the silica which replaces a limestone ?
1 ' Whetstones and the Novaculites of Arkansas/ p. 133.
* ' Des Caracterea distinctift de la Dolomite, etc., Bull. Acad. roy. Belgians
•er. 2, vol. xlvii. (1879) p. 502.
■1 ' Whetstone* and the Novaculites of Arkansas,' p. 205.
* ' The Occurrence of Colloid Silica in the Lower Chalk of Berkshire and
Wiltshire/ Quart. Journ. GeoL Soc. vol. xlv. (1889) p. 407.
2n2
Digitized by Google
MR. F. RUTLET OX THE ORIGIN OF
[Aug. 1894,
The late John Arthur Phillips, in speaking of the siliceous
deposits at Steamboat Springs, Nevada, U.S., remarked that 44 the
fissures, which appear to have been subjected to a series of repeated
widenings, such as would result from an unequal movement of their
walls, are lined, sometimes to a thickness of several feet, by incrus-
tations of silica of various degrees of hydration, containing hydrated
ferric oxide and, exceptionally, crystals of iron pyrites. This silica
exhibits the ribbon-like structure so frequently observed in mineral
veins, and, when examined under the microscope, is seen to consist
of alternately amorphous and crystalline bands, enclosing druses
lined with minute crystals of quartz."
Speaking of an older group of fissures, about a mile west of the
last-named locality, he adds: — "The silica of this deposit is sometimes
cbalcedonic and contains nodules of hyalite ; the larger proportion
of it, however, although somewhat friable, is distinctly crystalline.
The crystals contain numerous liquid cavities, and exhibit the usual
optical and other characteristics of ordinary quartz." 1
The foregoing statements prove, I think, quite sufficiently, that
deposits of silica may pass from the amorphous into the crystallized
condition, and, bearing this in mind, it appears by no means improbable
that like changes may occur in the silica which replaces a limestone.
Mr. Griswold regards the siliceous grains which constitute the
Arkansas novaculites as quartz. The specific gravity of Arkansas
stone, however, is given by him as 2*648 or, making allowances
for the u excess of weight caused by the presence of the heavier
elements," 2-643. He adds that 44 this falls within the limits given
for silica in the form of quartz (4 Chemiker-Kalender ' for 1888),
which places the specific gravity at from 2-64 to 2-66. The specific
gravity of novaculite may be a trifle lower than the average for
quartz, since some air may remain in the pores of the stone and
decrease its weight in water by a small amount." 2
In order to avoid any error due to the presence of cavities, I
reduced fragments of the translucent Arkansas stone to fine powder,
and employing the pyenometer and distilled water at 15° C., found
the specific gravity to be 2*6441. The weight of powdered stone
used was 2£ grammes, and every precaution was taken to ensure
accuracy. Mr. Griswold's estimate, 2*643, approximates very closely
to this, but in either case it seems that the specific gravity comes
rather within the range of chalcedony than of quartz. Prof. J.
D. Dana gives the specific gravity of chalcedony as 2*6 to 2*64,
which agrees with that of Arkansas stouo, while for quartz he gives
2*653 to 2*654, and for crystals of quartz from Herkimer he cites
Penfield's determination as 2-66. 5
All of these figures for quartz are higher than those for Arkansas
stone. So far, therefore, as specific gravity is concerned, Arkansas
■ • Ore Deposits.' 1884. p. 70. *
* ' Whetstone* and the Nofuculite* of Arkansas/ p. 93.
» ' System of Miaeralogy,' 6th ed. 18U2, p. 186.
Digitized by Google
Vol. 50.] CERTAIN N0VACULITE8 AND QUARTZITE9.
385
stone appears to have a better right to be regarded as chalcedony
than as quartz.
On p. 92 of his work, Mr. Griswold says : — " As the silica of
novaculite is neither crystalline, amorphous, nor chalcedonic, it must
be classed with those minerals which are structurally too fine to
show distinctive characters and are called cryptocrystalline. Thus
novaculite becomes a member of the same cIsbs of rocks with
chalcedony, flint, basanite or touchstone, chert, and jasper, a group
of rocks to which novaculite would, from its physical appearance,
seem naturally to belong." This statement appears to be true. It
may, however, be observed that, although this author says the silica
of novaculite is not chalcedonic, chalcedony is usually regarded as
one of the cryptocrystalline varieties of silica. It should, never-
theless, be noted that this evident slip of the pen is covered by the
concluding portion of the passage just quoted. Again, on p. 90 of
his work, Mr. Griswold states that " the remarkable fact demon-
strated by the analyses is the very constant, high percentage of silica.
Experiments on the solubility of the silica in caustic potash show
that it is almost entirely in the anhydrous form. There would,
therefore, be but little silica in the rock having the chalcedonic
structure, since chalcedonic silica is partly hydrous and pretty
soluble in caustic potash. Five per cent, is about the average
of soluble silica in the Arkansas stones as obtained by these tests.
This may seem rather high, but when it is considered that by
the same tests quartz-crystals, which are supposed to be practically
insoluble, give an average of about 4 per cent, of soluble silica, the
conclusion is reached that the silica of the novaculite is in a very
stable form. Two specimens of chert tested in the same way gave
over 30 per cent, of soluble matter, most of which was silica."
The last statement is no doubt true, but cherts differ, and, in
one analysis by Mr. E. T. Hardman, only a trace of soluble silica was
present, while in another made by him, also of an Irish chert from
the Carboniferous Limestone, the amount of silica soluble in caustic
potash was merely 0*95 per cent. 1
Mr. Griswold, on p. 91 of his work, quotes the opinions of
other writers, and among them the following : —
" Mr. G. P. Merrill guestions the theory of interlocking crystals to
account for the grit of the Hot Springs novaculite. He says that,
as a result of his own investigations, it is composed of * a very fine
and compact mass of chalcedonic silica in which are embedded
widely-scattering angular grains of quartz '." 3 I agree with Mr.
Merrill, but, so far as the grit of the Ouachita stone is concerned, I
am inclined to think that the presence of minute grains of garnet
may have a certain influence.
Mr. Griswold further says that " Br. J. C. Branner, State Geolo-
gist, declares his disbelief in the theory that all the novaculites are
metamorphosed sandstones, and suggests that the 4 compact varieties
1 ' The Chemical Compoaition of Chert, etc/ Sci. Trans. Roy. Dublin Soc.
toI. i. (new aeries) p. 90.
2 ' Mineral Resources of the United States,' 1886, p. 589.
Digitized by Google
386
MR. P. RUTLKY OX THE ORIGIX OF
[Aug. 1894,
of novaculite usually known as Arkansas stone ' have been produced,
not from sandstones or quartz, but by the metamorphism of chert." 1
Dr. Branner seems to have neared what I believe to be the truth.
Many other opinions are quoted by Mr. Griawold, some of them
conflicting. His own views are given in the following words : —
" Still it might be possible that the Arkansas novaculites were
metamorphosed cherts, were it not that their microscopic examina-
tion disproved the idea of great metamorphism. The fine grains of
silica composing the groundmass of the novaculites are not cemented,
but seem to be merely jammed together, the tenacity of the stone
being due to the interlocking of the irregular edges of the grains.
In the Ouachita stone are perfect rhombohedral cavities, about
which the fine grains of silica are closely packed in a layer show-
ing orderly arrangement ; outside this layer the granules have no
orderly arrangement. In an early stage of the history of the rock
the rhombohedral cavities undoubtedly contained crystals of caicite
or dolomite ; in fact, these crystals must have formed while the
grains of silica were yet free to move about, that is, while the rock-
material was in a soft condition similar to that of mud or ooze on
the sea-bottora. That the silica-particles were free to move is
shown by the fact that those granules immediately surrounding the
crystallizing caicite arranged themselves with their long axes per-
pendicular to the faces of the calcite-crystals. Thus the caicite
crystallized out in the original slime on the sea-bottom, or in the
still plastic beds below the slime ; and it is noticeable that the
calcium carbonate formed the tiny separate rhombohedra uniformly
distributed through the rock, just as one would expect the fragmcntal
carbonate to be distributed in an original sedimentary deposit,
instead of collected together into concretions or into separate layers.
The fact that the carbonate of lime did not gather into layers
or concretions may indicate that the sedimentation was a rapid
one." 3
From this view I dissent. I do not believe that such rocks are
Bcdimentfl, but that they are siliceous replacements of dolomite or of
dolomite Hmcstone-betU.
Furthermore, I can find no evidence that the siliceous granules
arc always arranged with their long axes perpendicular to the walls
of the rhombohedral cavities. Sometimes they are, at others they
are not ; but, as a rule, there is, as Mr. Griswold points out, au
orderly arrangement of these granules around the margins of the
cavities, a circumstance which tends to confirm the belief that the
rhombohedra of dolomite existed before any deposition of silica took
place around them. It is, indeed, often hard to recognize which
is the longest axis of one of these siliceous granules, but there is
no doubt that there frequently is a very decided direction of elon-
gation in the grains bordering the rhombohedral cavitiee. On the
other hand, iu these directions of elongation it is clear, as shown by
using the quartz- wedge, that the optical orientation is not always
the Ban
1 • Whetstones and the Novaculites of Arkansas,' p. 170. a Op. tit. p. 187.
Vol. 50.] CERTAI1T HOVACUXITB8 AND QUARTZTTES. 387
Had the rhombohedral crystals been formed in the manner sug-
gested by Mr. Griswold it seems doubtful whether they would have
been so perfectly developed. Moreover, if the surrounding material
consisted of already-formed quartz-grains, there would not have been
the selective arrangement of grains around the rhombohedra which
is so well shown, at times, in Ouachita stone. Had the rhombohedra
been formed last, they would have pushed the surrounding grains
aside, or have enveloped them, and of this there is no dear evidence.
To my way of thinking, all points to the solidification of silica around
already-formed crystals of dolomite.
If the views advocated in the present paper bo correct, we have
here, in these Arkansas novaculites, a case of metasomatosis on a
large scale. Mr. Griswold states that the novaculites " occur in mas-
sive strata, usually presenting plane surfaces and having only thin
layers of shale iuterbedded. Five or six hundred feet is the common
thickness of the novaculite formation, which generally includes some
flinty shales and soft shales or sandstones. The novaculites proper
are the prominent members of the formation, however, and occur in
massive beds from a fow inches to twelve or fifteen feet in thickness.
When thinner than about four inches the beds generally lose their
novaculite character and are more like flinty shale/' 1
There seems nothing improbable in beds, of the thickness above
cited, being wholly replaced by silica. Prof. Hull states that " in
the south-western districts of Tipperary, Limerick, Kerry, and Cork,
the principal masses of chert occur at the top of the limestone, im-
mediately below the shales of the Yoredale series, and sometimes
are so abundant as almost completely to replace the limestone itself.
.... At the foot of the ridge west of Carlow, the limestone is com-
pletely replaced by masses of greyish chert in thin layers, and over
thirty or forty feet in thickness." 8
If the beds of novaculite be a siliceous replacement of limestone-
beds, it by no means follows that their thickness indicates the former
thickness of the limestones, since the removal of limestone may have
been greater by far than the amount which has been replaced by
silica.
In connexion with the rhombohedral cavities, it may be pointed
out that the component rhombohedra of a dolomite are not all of
the same size, as shown in PI. XIX. fig. 6, although there is a
general uniformity in this respect. Some of the rhombohodra aro
occasionally 15 or 20 times as large as others, and these larger crystals
would take longer to dissolve and would probably form a fair pro-
portion of the residue which ultimately became imprisoned in the
silica. That many of the dolomite-crystals were more or less eroded
is evident from the irregular forms of some of the cavities in the
Ouachita stone.
• ' Whetstone* and the Novaculite* of Arkansas,' p. 94.
* ' On the Nature and Origin of the Beds of Chert in the Upper Carboniferous
Limestone of Ireland,' Soi. Trant. Boy. Dublin Soc. toL i. (new series) p. 75.
Digitized by Google
388
MR. F. RUTLEY ON THE ORIGIN OF
[Aug. 1894,
In this papeY the belief has already been expressed that structural
gradations might be traced from Arkansas stone to rocks which
would generally be recognized as quartzites, but it remained to be
shown whether such a structural series could in each instance, or in
every grade, be referred to a similar origin : namely, whether, at the
two extremes of such a series, rocks could be found which could be
proved to be siliceous replacements of limestone.
The example which we shall next consider will, I think, help to
do this, since, in point of structure, it approaches more nearly to a
quartzite than any limestone-replacing rock with which we have yet
had to deal. The specimen approaching nearest to quartzite which
has hitherto been mentioned is the pebble from Purtiall. This
seems to form a link between what we recognize as the cryptocrys-
talline and microcrystalline conditions. That these conditions have
no distinct individuality is, I think, almost certain, since they appear
to depend upon the size of the crystals or grains in relation to the
thickness of the section, while the dark lines, which seem to be the
sinuous outlines of interlocking grains, when the section is examined
between crossed nicols, are seen to wander and frequently form ir-
regular contracting and expanding rings as the section is rotated.
That this phenomenon is due to compensation, brought about by the
squamose overlapping of small crystals or crystalline grains, which
react upon one another as diminutive quartz- wedges, seems highly
probable.
Fig. 1. — Auriferous quartzite from Nondweni, Zululand.
(Ordinary light.)
x HO.
q — quartz, c = calcite.
Some time ago several specimens were sent me from Zululand by
my late sister-in-law, Mrs. Jenkinson. They were from the Zululand
Gold-fields, and bore no other label ; but Mr. Graham Jenkinson,
during a recent visit to this country, was able to give me the locality
Digitized by Google
Vol. 50.]
CERTAIN NOVACFLITES AND QUARTZITES.
389
of certain bluish-grey, auriferous quartzites, which he recognized as
similar to those occurring at Nondweni.
A section cut from a small hut rich fragment shows, when examined
under the microscope, that the rock is a quartzite, but that, in
addition to gold, it also contains a very considerable amount of
calcite. The quartz appears in polarized light as a mosaic of crystals
and irregular grains, which give positive uniaxial figures in con-
vergent light. The calcite occurs in irregular patches, strings, and
finely-shredded particlos. The patches sometimes show very distinct
rhombohedral cleavage. Frequently small crystals of quartz occur
within, or irregularly mixed with, the calcite, and occasionally the
latter mineral appears as if squeezed between the crystals of quartz
(fig. 1, p. 388).
Careful examination of the section leads to tho conclusion that the
calcite does not form true veins in tho quartzite, since the sharp
boundaries which almost invariably characterize veins are not present.
The calcite appears shattered, frayed, or shredded out where it comes
into contact with the quartz, suggesting tho disintegration of tho
former by a solvent (fig. 2). It might be urged that both the calcite
and tho quartz crystallized simultaneously, but I can see no proof of
this, appearances pointing rather to the disintegration of pre-existing
calcite and infiltration of silica, which crystallized out as quartz.
Fig. 2. — Auriferous quartzite from Nondweni, Zululand.
(Ordinary light.)
x 140.
q = quartz, c — oaleite.
The gold occurs in irregularly-shnped particles, sometimes appa-
rently in octahedral crystals, and it is mainly situated in the calcite.
In some cases, however, it lies partly in calcite and partly in quartz,
while, to a small extent, it is disseminated in the quartzose portions
of the section.
It would appear, then, that the gold originally occurred in a bed
Digitized by Google
300
MB. F. RUTLEY OX THK ORIGIN OF
[Aug. 1894,
of limestone, the latter having since been in great part dissolved and
replaced by quartz, which has taken up some of the gold it contained.
The quartz envelops a residue of the limestone, the marginal portions
of the included limestone-patches showing that the process of dis-
integration was going on when it was arrested by the solidification
of the silica (fig. 2, p. 380).
The brisk evolution of bubbles when a fragment of the rock is
placed in dilute hydrochloric acid indicates that the carbonate is,
in this case, not dolomite, but calcite. A drop of the solution, when
treated with chloride of ammonium and ammonia, and phosphate of
soda added, yields a few microscopic crystals of the ammonio-phos-
phate of magnesia ; but this magnesia is doubtless derived from a
pale greenish substance, which is present here and there in the
calcite, and which may be regarded as probably some variety of
chlorite.
We have, then, in this rock a case in which a quartzite of com-
paratively coarse microscopic texture has originated as a siliceous
replacement of a limestone, just as I believe the fine-grained
Ouachita stone and the still finer Arkansas stone are the siliceous
replacements of dolomites or of dolomitio limestones.
Although the association of gold with calcite is unusual, it is
by no moans unknown. Thus, the late John Arthur Phillips, in
describing the St. David's Lode (Clogau Mine, North Wales), says : —
u It is chiefly composed of quartz and calcite, the latter mineral
sometimes forming masses of several feet in width ; where the
calcite assumes the appearance of a friable and granular marble, it
not unfrequently contains gold, but when, on the contrary, it
becomes foliated or is coarsely granular, that metal appears to be
entirely wanting." 1
It may be that the evidence adduced in support of the views
advanced in this paper will not prove conclusive to all minds. Those
views were, in fact, laid before this Society in a former paper,3 to
which this may be regarded as a sequel. It is but a very imperfect
sequel, since I hoped to have been able to discuss the differences
between concretionary and residual limestone-nodules, but, in the
absence of suitable material to work upon, this portion of the subject
could not be dealt with.
In conclusion, I am anxious to express my profound appreciation
of Mr. Griswold's work, although I have occasionally taken tho
liberty to criticize it. To do it justice would, indeed, be no easy
task. His book is a mine of facts, a storehouse of well-arranged
and valuable information. Upon several of the points on which I
have ventured to differ from Mr. Griswold, he has himself expressed
doubt, and I have therefore felt the less diffidence in attempting to
explain that which seemed obscure.
1 ' Or© Deposit*, ' p. 203.
a ' On the Dwindling and Disappearance of Limestones,' Quart Journ. Geol.
Soo. vol. xlix. (1803; p. 372.
Digitized by Google
VoL 50.]
CERTAIN NOVACULITES AND QUARTZTTE8
391
[Postscript. — On perusal of the remarks made by Dr. Hinde, in
the discussion which followed the reading of this paper, it would
appear that, in stating the thickness of the novaculite-formation
with its shales and sandstones, he lost sight of the fact that the
novaculites themselves occur in beds which, according to Mr. Oris-
wold, range from only a few inches up to 15 feet in thickness.
There is nothing improbable in the erosion or replacement of lime-
stone-beds of such dimensions. With regard to the question : What
became of the limestone? it can only be answered that, if once
there, as I believe it to have been, it was carried away in solution :
the usual fate of limestones. As for the silica, it is difficult to
express any decided opinion concerning the source from which it
was derived. It may have been deposited from thermal waters. —
May 23rd, 1894.]
EXPLANATION OF PLATE XIX
Fig. 1. Arkansas stone, x 380. Crowed nicols.
Fig. 2. Flint-pebble, Thames Gravel, x 380. Crossed nicols.
Fig. 3. Ouachita stone. The dark patches are spaces due to cavities, often of
distinctly rborabohedral form, once occupied by crystals, probably of
dolomite, x 140. Crossed nicols.
Fig. 4. Siliceous rook, approximating to quartzite and containing rbombohedral
crystals of a carbonate, probably dolomite. From conglomerate.
Purtiall, Deccan, India. X 140. Crossed niools.
Fig. 5. Magnesian limestone, occurring in the Carboniferous Limestone Series.
Cumberland Cavern, Matlock Bath, Derbyshire. X 140. Ordinary
light
Fig. 6. Rhombohedra of dolomite derived from the preceding specimen by the
action of dilute hydrochloric acid, x 140. Ordinary light.
Fig. 7. Pebble from conglomerate, Purtiall, India. Edge of the same section
as that represented in fig. 4. X 380. Crossed nicols.
Fig. 8. Auriferous quartzite, Jiondweni, Zululand. Edge of quartxose portion
of section, x 380. Crossed nicols.
Figs. 9 & 10. Forms of cavities in Ouachita stone, once occupied by partially
eroded crystals of dolomite. X 75.
DlBCUBSIOX.
Dr. G. J. Hinde complimented the Author on the ingenuity of his
explanation of the origin of the Arkansas novaculite-rocks, but failed
to see that there was any evidence for his fundamental assumption
that theae rocks were originally limestones or dolomites which were
now replaced by silica. Taking into account that the novaculites
wore over 500 feet in thickness, and that they were interbedded with
shales and sandstones, it might reasonably bo asked what had
become of the limestone of which they were originally supposed to
be formed, and also whence the silica had originated which was
stated to have replaced the limestone ?
The speaker did not agreo with Mr. Griswold that the novaculites
were produced by simple sedimentation of fine fragmental silica ;
but he considered that their structure of cryptocrystalline silica,
and their resemblance to Chalk-flints in microscopic characters,
which M>. liutley had pointed out, indicated that, like these latter,
Digitized by Google
392 ORiom of wovaculites ahd quartzites. [Aug. 1894,
they might hove had an organic derivation. Moreover, in the beds
of Carboniferous chert from Ireland, Belgium, Yorkshire, Wales,
etc., and in the cherts of the Durness Limestones (sections of which
were exhibited), there wore numerous rborabohedral crystals of
calcite, the same as in the novaculites, and they also resembled these
in other respects. As these cherts had been proved to be derived
from the siliceous remains of sponges, it might well be supposed
that the silica of the novaculites had a similar origin. It was true
that no siliceous organisms had as yet been found in the novaculites,
but this might arise from imperfect observation, or it might be that
the changes which had taken place in the rocks had obliterated
them.
Prof. Hull remarked that the chert-beds of the Upper Car-
boniferous Limestone of Ireland, referred to by the Author, and
described in the joint memoir by the late Mr. Hardman and
himself, were composed of variable proportions of carbonate of lime
and silica, and also contained silicified shells, corals, and crinoids —
animal structures that must primarily have been formed in carbonate
of lime : thus proving that the rock had originally been to a great
extent a limestone. Along with these structures were numerous
spicules of siliceous sponges, recognized in the thin slides by
Dr. Hinde. But the rock described by the present Author, so far
as he had been able to gather, was of quite a different character
from these Carboniferous chert-beds. It was a solid quartzite,
without evidences of having contained marine calcareous organisms;
and however ingeniously the Author had succeeded in showing, by
means of his researches in the laboratory, that a limestone might
be changed into a quartzite, he (the speaker) feared that without
some better evidence of so remarkable and fundamental a change in
the composition of the Arkansas rock described, Mr. Rutloy's views
could scarcely be accepted.
The Author, in reply to Dr. Hinde's remarks, stated that he had
purposely refrained from expressing any opinion concerning the
source from which the silica of the novaculites had been derived.
Dr. Hinde was doubtless correct in assuming that the silica of chert
was frequently composed, at least in part, of the remains of sponges.
He had not detected any sponge-spicules in either Arkansas stone
or Ouachita stone. He also briefly alluded to the observations of
Prof. Hull.
Digitized by Google
Quart ..ioum.Geoi Soc. Vol L. PI XIX
7J
Fn*nk Ptotlay oei P H MicW. ttth
N OVAC U 1 .11 K S , QUART Zl TES ,
AND DOLOMITES.
Mmlernfirw
Digitized by Google
Vol. 50.]
MR. B. THOMPSON OX LANDSCAPE MARBLE.
3'Ki
25. Landscape Marblr. By Berby Thompson, Esq., F.G.S., F.C.8.
(Read March 7th, 1894.)
Contests.
Page
I. General Description of the Landscape Marble 393
II. Specific Description of the Landscape Marble 394
III. Its Microscopic Characters 390
IV. Its Chemical Characters 398
V. Its Mode of Occurrence 399
VI. Theories as to the Origin of the Landscape Marble 399
VII. Mode of Formation of the Landscape Marble 401
VIII. Experiment* made to reproduce the Characteristics of Landscape
Marble 405
IX. Conditions under which the Landscape Marble was formed 40tt
I was led to a study of the structure and origin of the so-called
Landscape Marble, or Cotham Stone, through reading an article in
the Geological Magazine for 1892, p. 110, by Mr. H. B. Woodward,
entitled, 4 ltemarks on the Formation of Landscape Marble.' To
that article I am much indebted for information as to the general
characteristics of the stone, and its mode of occurrence.
The first published description of the Landscape Marble occurs
in a work by Edward Owen, the title of which is • Observations on
the Earths, Rocks, Stones and Minerals, for some miles about
Bristol, and on the Nature of the Hot Well and the Virtues of ita
Water ' ; the date on the title-page being 1754. The name 'Cotham
Stone ' was applied to the Landscape Marble because it was
quarried, with other material, near Cotham House, on the northern
side of Bristol, but Owen did not give it this name ; he merely
adopted the appellation by which it was already known in that part
of the country (op. cit. p. 164).
At the time of Owen the Cotham Stone was chiefly known by
and valued for its peculiar, corrugated, upper surface, « rustick '
so-called, though some cut and polished specimens were to be found
framed in tho houses of * the gentlemon of the neighbourhood.'
For convenience of roference, I shall number the descriptive
paragraphs throughout this paper.
I. General Description op the Landscape Marble.
1. It is a hard, close-grained, argillaceous limestone, which breaks
with a fracture almost as conchoidal as Hint ; and it takes a
moderate polish.
2. #It shows no distinct evidence of concretionary origin, although
concentric layers will sometimes flake off the upper surface.
3. The uj>per surface is often much wrinkled, and the irregularities
appear to correspond with the original pianos of deposition, for
when a layer flakes off it follows these irregularities. The wrinklings
Digitized by Google
394
MR. B. THOMPSON ON LANDSCAPE MARTILE.
[Aug. 1894.
on the surface are often curiously interlaced, giving rise to the
so-called 'rustic-work* for which the stone was chiefly quarried.
Owen speaks most enthusiastically of the ' rustick ' thus : — " When
I have viewed the whole thus nearly, it appeared not a piece of
common rustick, but an imitation of something much more elegant.
The depths of the hollows between the rising parts is varied, and
their form different, in so strange a manner, that no two are at
all alike : and the waving and curdlings of the surface in the
raised parts is such, that every one of them seems a piece of
rustick in miniature, the whole surface being formed, like that of
the mass, into risings of the most elegant kind, and irregular hollows
between them" (p. 166). Owen also refers to the scaling (p. 167).
4. The interior of the stone is characterized by dark markings,
which pervade the stone between certain limits, and have much
the appearance of foliage.
Tho markings rise from a more or less stratified base, spread out
as they rise, and terminate upwards in the wavy banded portion of
the limestouo; the whole varying from 1 to about 9 inches in
thickness.
As the markings are disposed more in a vertical direction than
laterally, in order to show them the stone is usually cut and polished
at right angles to the stratification.
5. Two landscapes are shown in some specimens, one above the
other, but each arising from a distinct dark layer. A very fine
specimen with a double landscape is to be seen in the Museum of
Practical Geology, Jermyn Street.
II. Specific Description op the Landscape Marble.
Under this head I propose to describe more minutely the
characteristics of tho specimens in my own possession (though I
believe them to be quite ordinary examples), because some im-
portant points of structure do not appear to have been noted by
previous observers.
6. The whole thickness of the stone way he regarded as matie up
of three distinct portions, the upper and lower being striated and
the middle irregular, through the interposition of the arborescent
markings (see figs. 1 & 2, pp. 395, 397), and in the specimen that I
shall particularly refer to, tig. 1, the general curvature of each
layer, as well as the striaB in it, is just about the same, the inner
edge being an arc of a circle of about 4 j inches radius, and the outer
edge, approximately, an arc of a circle of 7£ inches radius.1
7. The lower portion of the stone is about 1} in. in thickness,
and at first looks as though very sharply divided into two by
difference of sediment, and a line of cleavage ; neither of these
surmises, however, can be retained after a microscopic examination.
The lowest (A) is light yellowish-brown in colour, and longi-
1 Mr. H. B. Woodward observes that the lower surface of the limestone is
even, though sometimes in small masses ol the rock it is gently curved.
Digitized by Google
by Ggogle
396 MR. B. THOMPSON ON LANDSCAPE MARBLE. [Aug. 1 894.
tudinally striated with thin, darker brown marks. This is rather
less than £ inch thick.
The next portion above (B) is about ^ inch thick, of a grey colour
mostly, and is longitudinally striated with darker, almost black
marks.
The striaD in A and B vary in distinctness and distance from each
other, but average about 20 to the inch.
8. The middU portion of the stone is that part where the character-
istic arborescent markings occur, which it is the special object of
this communication to explain.
At the base is a dark layer (C) conforming in general curvature
with the layers below, but extremely irregular in structure, the
upper part being very jagged (the hedge).
Above the last, but springing from it, arc the more decided
arboroscent markings (/>), which may rise in the form of a single
stem and then spread out (trees) or may. spread out at once (shrubs).
Between the arborescent parts there is a light-coloured matrix
(E), striated, but in a very erratic manner, so that the imaginative
eye may see clouds, mountains, lakes, etc Amidst all the confusion
here, however, there is uniformity in one thing, atid this is most
important : the striae of the matrix are always directed upwards near
the dark markings, aud dip downwards between them.
This part of the stone may be taken as 1 £ inch in thickness.
9. The upjier jiortion of the stone greatly resembles the lower in
change of colour towards the outside, and in being striated, but the
uniformity of curvature has evidently been interfered with from
below and from above, for the striae rise over the arborescent
markings and sink between them, and this is almost exactly what
the outside of the stone does.
Just abovo the termination of the arborescent markings is a
layer, F, which is more generally dark, and more obscurely striated
than any other part.
Above the last, in the part marked (?, the striations become
again more distinct, but of a different colour, light yellowish-brown,
as at the bottom.
The thickness of the upper portion of the stone, jPand 0, varies
from \ to | inch.
III. Its Microscopic Characters.
1 0. " Tin rock is mainly composed of extremely Jins granular calcitf,
and contains a few very small grains of quartz. In the part which
shows the characteristic markings there are patches of clear and
sometimes coarse-grained crystalline calcite." 1
1 1 . TJie arborescent markings and the strict are composed of a form
of carbonate of lime which takes a higher polish than the mass of
the stone. In the specimen shown in tig. 1 (p. 395) they are entirely
composed of coralloidal aragonite, whereas in the other (fig. 2, p. 397)
1 J. J. H. Teoll, quoted in H. B. Woodward'g paper, p. 113.
Digitized by Google
MR. U. THOMPSON" ON LANDSCAPE MARBLE.
[Aug. 1894,
they seem to differ from the matrix only in being finer grained. In
all cases the outer boundary of the dark markings seems to be de-
cidedly darker than the central portion.
12. Other points brought out by the microscope are these : —
The dark markings, where composed of aragonite, are nearly
uniformly coloured throughout, except at the outer boundary where
contiguous to the granular calcite ; whereas in the other specimen
(tig. 2, p. 397), whore they still retain much of the granular structure,
they are spotted all over with darker patches, as dark as the outer
boundary.
The outer striated parts of the stone, which in one specimen are
of a different colour (see 7 & 9),' are exactly similar to the darker
striated portions contiguous to them, except in colour.
The change of colour is in the compact aragonite, and not in
the granular calcite.
The two colours, grey (inside) and yellowish-brown (outside), seem
to be very sharply defined, and to follow the stria) when the stone is
viewed by tho unaided eye : under the microscope this is seen not
to be the case, the change in colour is gradual, and the striae cut
indifferently through grey and brown.
13. Thin veins of cnlc-spar in larger crystals are found, in what
are considered inferior kinds of Landscape Marble, and they may
cross the stono or follow the striae. These may often be seen quite
readily without the microscope. Edward Owen remarks (p. 180)
that these veins are broadest towards the bottom, and narrowest
towards the top. This is the case in my specimen ; indeed, the most
prominent crack does not extend far into the arborescent markings
(see SS, fig. 2).
IV. Its Chemtcal Characters.
14. The stone is violently attacked and rapidly dissolved by
dilute hydrochloric acid, with the exception of a small quantity of
brown argillaceous matter.
The aragonite dissolves more rapidly than the granular calcite,
thus soon producing a very uneven surface.
15. The stone consists chiefly of calcium carbonate, but the
solution in hydrochloric acid also contains iron, aluminium, man-
ganesc, magnesium, and a little j)ho8j)horic acid.
In addition to these thero is tho argillaceous matter and the
quartz, which are insoluble. By washing the former of these, and
examining it under the microscope, a few grains of the latter may
usually be found.
It is also tolerably certain that there is some carbon associated
with the darker markings, to which in fact the colour is due, for the
stone is bleached on ignition. A white spot may be produced in a
1 Numbers within parentheses, here and elsewhere in this paper, refer to the
numbered sections of the description.
Digitized by Google
Vol. 50.] MB. B. THOMPSON ON LANDSCAPE MABBLE.
399
few seconds by directing a jet of flame on to the dark part by means
of a blowpipe.1
V. Its Mode op Occurrence.
16. The stone occurs in isolated and lenticular masses which are
sometimes less than 1 foot across, sometimes 3 or 4 feet. A stone
some 2 feet in diameter or length is usually 8 or 9 inches thick
(Edward Owen, p. 172).
The stratigraphioal equivalent of the Cotham Stone occurs in
other places as a fairly persistent layer ; where this is so it is
oanded and evenly bedded, but the arborescent markings and crinkly
upper surface are wanting. Between the ordinary banded limestone
and the distinctly arborescent types many intermediate varioties
may be found.
17. The stone is not very continuous, even where it takes the bed
form, although met with more or less over a large area. It may be
that at some places the bed is present, but not identified, because of
the absence of the arborescent markings.
18. The jmition of the Cotham Stone is in the Rha>tic Beds, at or
near the junction of the black Avicula conforfa-shales with the
overlying beds of White Lias, that is, between dark argillaceous sedi-
ment and almost pure calcareous mud, though in some localities a
few inches of dark clay may be found above the stone.
VI. Theories as to the Origin op the Landscape Marble.
Edward Owen, who first described the Landscape Marble, thought
that the arborescent markings were produced by the escape of im-
prisoned air. Some have thought that gaseous emanations from the
black mud of the Avicula contorta-Bholes had something to do with
the peculiar structure of the marble. Others again have considered
that infiltration of dark mineral matter would account for it.
Mr. H. B. Woodward's recent explanation of the origin of the
Landscape Marble 3 is as follows : — " It appears to me that the
arborescent markings were produced during the consolidation of
the stone, and more particularly by the shrinking of its upper
portions. In this way, and while the mud was still in a more or
lees pasty condition, one or more of the dark films in the banded mass
were disarranged and dispersed in arborescent form in the slowly
setting rock .... It may bo that the production of the isolated
masses of rock, with their irregular upper surfaces, was attended by
some pause in the deposition of sediment, and by exposure of the
layers to the sun's rays . . . The process of formation of the Land-
scape Marble seems to me to have been mainly mechanical, although,
1 Since writing the above I have read the following passage : — ' Mr. Allan
Dick, who has kindly examined a specimen of the Gotham Marble, tells me
that dark portions of the stone are not due to the presence of manganese- or
iron-ores, hut are probably due to carbonaceous matter.' — Mem. Geol. Surv.
1893, ' The Jurassic Rooks of Britain,' by H. B Woodward, yoI. iii. p. 31.
> Geol. Mag. 1892, pp. 112,114.
2b2
Digitized by Google
400 MR. B. THOMPSON 017 LA2TD8CAPE MARBLE. [Aug. 1 894,
as might be expected, there is evidence also of chemical change.
In attributing the corrugated surfaces to the shrinking of the
calcareous mud, I may have appealed too strongly to mechanical
causes, as apart from the obscure processes of segregation, or even
of concretionary action.*
A perfect explanation of the origin of the Landscape Marble
should, of course, account for all the characteristics enumerated
(1 to 17) ; but if this be impossible we must remain content with one
that will account for the greater number, without being obviously at
variance with any. Let us first of all clear the ground of those
explanations or theories, or parts of theories, which are at variance
with the known characteristics of the stone, so that the explanation
which I shall presently offer may be less encumbered.
The escape of imprisoned air. — Edward Owen's theory cannot be
entertained as an explanation, even if we give 4 air ' the wider
signification of 4 gas/ which it may have had to Owen in 1754, for
gas could not have been imprisoned in a fine soft mud such as this
stone must have been when forming; nevertheless, after reading
Owen's description, I am inclined to think that he had a clearer
conception of the method of formation than he was able, through
lack of chemical knowledge, to express.
Gaseous emanations from the black mud of the Avicula contorta-
shales (18) must also be discarded as a theory, for the simple reason
that in most specimons, perhaps in all, the lower portion of the stone
(the part that rested on these shales) is quite free from the black
arborescent markings, and in place of them are horizontal ones
alternating with other sediment (7). The not uncommon presence
of two landscapes (5) is also quite inexplicable by this theory.
Infiltration of dark mineral matter cannot be accepted as a cause
of the arborescent markings, because they spread out upwards and
not downwards, and because they are bounded, both above and
below, by the same dark matter in regular bands lying in an
approximately horizontal position (4-0), and also because the mark-
ings are much too large, and much too distinctly and evenly bounded
(11). For the same reasons, and others, mere staining is quite out
of the question.
Shrinkage of the stone, whether before or after consolidation,
cannot alone be admitted as a cause of the arborescent markings,
though for other reasons we must admit considerable shrinkage.
Shrinkage after consolidation could not have caused it, because
then there would be an absence of fluid or semi-fluid matter such as
must be postulated to account for one kind of mineral matter
becoming so irregularly mixed with another.
That shrinkage before or during consolidation cannot be admitted
as a cause is equally certain, because in such a fine-grained rock as
this (1, 10) the interspaces between the particles (or crystals, if
they then existed) of the matrix would be much too small to admit
of the intrusion of such comparatively large masses of foreign
Digitized by Google
Vol. 50.]
MR. B. THOMPSON OX LANDSCAPE MARBLE.
401
coloured matter.1 The darker matter must necessarily have been
more fluid than, and quite as finely constituted as the matrix to
have been displaced by and dispersed in the latter, and then a kind
of marking to which the term * dendritic ' is usually applied would
have resulted. To me it seems impossible that one layer can be
fluid enough to be squeezed into anothor, and yet coherent enough
to move only in masses.
Again, if pressure wero the sole cause, why should not the dark
matter have been squeezed downwards below its point of origin as
well as upwards (4-9), and why were not the thinner horizontal
bands of dark matter also displaced (7, 9), or at least bent irregu-
larly, whilst the shrinkage was going on ?
VII. Mode op Formation op the Landscape Marble.
Perhaps it will be well to say here that I commonced my investi-
gation of Landscape Marble with the preconceived idea that its
peculiar characteristics were due to interbedded layers of vegetable
matter, which continued to decomjjose and evolve carbonic-acid gas
and marsh gas after its deposition ; and that where a layer of extra
thickness occurred the decomposition continued whilst a thickness of
several inches of new sediment was laid down, with the result that
arborescent markings were produced along the lines taken by the
escaping bubbles. The excessively wrinkled upper surface of the
stone seemed to necessitate a central portion capable of consider-
able shrinkage, and organic matter provided such a material.
A careful examination of all the characteristics of the stone, and
some experiments aiming at its artificial reproduction, have con-
firmed the main idea, but have caused me to modify the expla-
nation of the formation of the crinkled upper surface.
The rock was without doubt a sedimentary one (1, 4-9, 16, 17) ;
it occurs in the midst of sedimentary rocks (18), and is intimately
associated with a fairly persistent bed (16), although it might at
times appear to be merely a concretion (2). The flaking off some-
times observed is due to original difference of sediment (3), and to
the present different physical characters of the light and dark
matter respectively ; it occurs in the nearly horizontal lower layers
as well as in the upper undulating ones (10, 11, 12).
It Juts undergone considerable change since its deposition, both
physical (1, 3-9) and chemical (10-13), at least so far as the re-
construction of some of the crystallizable matter and oxidation
of the outer layers in some specimens (7, 9) are borne in mind,
without as yet considering the changes in the organic matter con-
nected with the formation of the arborescent markings.
The conchoidal fracture of the stone (1) is a characteristic usually
observed in fine-grained limestones, I believe, and does not, therefore,
need special treatment.
1 One of the single stems, without bifurcation, I have found to be more than
} inch long, and from ^ to | inch wide.
Digitized by Google
402
MR. B. THOMPSON ON LANDSCAPE MAKBLE.
[Aug. 1894,
While the stone now called Landscape Marble was being formed
there were very frequent alternations of light-coloured and darker
matter deposited (7-9), and occasionally a dark layer of greater
thickness than usual was formed, with tho apparently inseparable
accompaniment of arborescent markings above it (4, 8) ; if two Buch
unusually thick layers occur there are two landscapes (5). Three
landscapes may and do occur, but I have never seen a specimen.
The connexion of tHe arborescent markings with the dark layer
from which they spring may, therefore, be regarded as beyond doubt,
though if other proof were needed it would be found in the facts
that they are of the same colour ; of the same lustre (11 ), which is
different from that of the matrix ; and of the same chemical com-
position and crystalline form (11, 12).
That the arborescent markings originated from the dark layer \ and
not the latter from the former, must bo obvious, from the following
considerations : — All the markings start from the dark layer,
whereas they finish anywhere, some only at half the height of
others (see fig. 1, p. 395) ; the narrowost portion is downwards
(4), whereas the opposite would be the case if the source had been
above. But the most conclusive reason of all is the invariable
lifting of the matrix contiguous to the dark markings (8).
The material of the dark bands and arborescent markings must
have been either more plastic than the matrix, or of a less dense
matter, to have allowed itself to be squeezed or lifted from its
original bed through overlying layers (4, 8). I think it was actually
both less dense and more fluid, for not only was it lifted through
comparatively heavy inorganic material, but when it reached the
surface it spread out in all directions, and produced exceedingly thin
films of dark matter which completely roofed in the arborescent
marks (9) ; see also fig. 1, p. 395.
Tfte dark matter could not have been a coloured fluid merely, for
although the matrix of the stone admits of staining, since it can be
bleached by weathering (7, 9, 12), no staining has occurred, the
outer boundary of the markings being sharply defined ; in fact, the
markings are distinctly darker along their outer boundary than
anywhere (1 1), except the spots in the spotted form (12), whereas
with ordinary staining the reverse would be the case.
It would appear, therefore, that the original material of the dark
markings was semi-fluid, and contained finely divided dark matter,
such as carbon or oxide of manganese, disseminated through it.
That carbon and not oxide of manganese (15) was the darkening
matter appears tolerably clear, for the following reasons:— The
dark parts are readily bloached by a blowpipe flame (15); in one
specimen darker spots are very unequally disseminated through
these parts (12); I have experimentally shown that bubbles of
carbonic-acid gas will lift and disseminate finely-divided carbon
from a layer covered with fine sand, whereas they would not lift
oxide of manganese ; and, lastly, carbon fits in much better with all
Digitized by Google
VoL 50.]
MR. B. TUOMPSO* ON LANDSCAPE MARBLE.
the other evidence as to an organic origin for the dark layers and
marks.
The mammillated or corrugated upper surface of Landscape Marble
(3) is so distinctive that it must evidently require an explanation
dependent upon the other peculiar characteristics ; ordinary desicca-
tion is quite inadequate, otherwise we should much more often
meet with similar characteristics in other stones. At first, I thought
that the excessive wrinkling of the upper surface of the stone was
due to exceptional contraction of the interior, and this an interior
composed partly of vegetable matter would give ; but I was quite
conscious that this was not all tho truth, because it did not suffici-
ently account for the wrinkling occurring only on the upper surface.
Since I commenced writing this paper I quite accidentally obtained
a very near approach to the appearance of the 'rustick ' on Landscape
Marble, thus: — Some zinc dust was mixed with copper sulphate
(Zn.Cu. couple); after some time the compound produced was
washed and left suspended in distilled water — I say suspended, for,
although prepared more than a month ago, it has never really settled,
but constantly occupies much more room than it would do as a dry
solid, leaving some water at the top quite clear. This preparation
has slowly, but continuously, evolved hydrogen, but to disengage
the bubbles, which are below the surface of the suspended matter,
a slight shake is necessary. The particular point, however, is this,
that whenever the vessel has been left quiet for a day or two the
upper surface of the solid is covered with hills and hollows greatly
resembling tho upper surface of Landscape Marble. When the flask
is shaken, bubbles of gas escape, the hills collapse, and gradually
an even surface is produced again. Tho bubbles of gas do not
generally escape from the hillocks, but rather from between them ;
nevertheless, when the gas has escaped the contiguous hillocks fall,
showing that the elevation of the surface of the solid was duo to the
upward pressure of the hydrogen.
I consider, therefore, that the uppor corrugated surface of the
Cothara Stone is chiefly due to the upward pressure of the same gases
that produced the arborescent markings, after their escape had been
prevented by increasing coherence or greater thickness of the upper
layers of sediment.
The fact that the arborescent markings rise where there is a
hillock, and that they are absent altogether under tho larger
depressions, at least in my specimens (see fig. 1, p. 395), renders the
above explanation all the more plausible, though shrinkage must
also bo given its just due (9).
The curvature of some sjxcimens of Cotham Stone is evidently a
later production than the stone itself, for it affects all the layers
aliko (6), and so need not detain us much. Since the curvature is
sometimes very irregular (see fig. 2, p. 397), it seems that it is most
likely duo to earth-movements.
The physical constitution of the Cotham Stone as revealed by the
microscope does not permit, perhaps, of so certain an explanation as
Digitized by Google
404
MH. B. THOMPSON ON LANDSCAPE MARBLE.
[Aug. 1894,
the macroscopic characters, but, in conjunction with the chemical
composition, it forms a study of much interest.
The fine granular calcite (10) may have been an actual deposit of
detrital matter from adjacent calcareous lands, or a chemical pre-
cipitate from warm shallow waters. I incline to the latter belief
for these reasons : (a) the limestone is fairly pure ; (h) the carrying
power of water which deposited such frequent alternate and very
thin beds of vegetable matter must have been insignificant.
The presence of small grains of quartz (10, 15) does not consti-
tute any great obstacle tu this idea, because they, together with
the argillaceous matter, may have been brought with the vegetable
matter.
The formation of Vie coralloidal aragonite, the presence of which
in one of my specimens so accurately coincides with the limits of
the arborescent markings and dark bands, is a problem of much
interest, and seems to point to organic matter as being sometimes
a determinative agent in the crystallization of calcium carbonate.
The superior lustre of the arf crescent markings and dark bands is
most obvious if a polished specimen of the stone be held before a
window, so that the light falls upon it very obliquely ; indeed, they
have then quite a metallic appearance, so much so that at first I
looked for a sulphide of some metal. In one specimen the higher
refractive power of aragonite accounts for its higher reflective power
than the calcite matrix, but its greater compactness or non-granular
texture may materially contribute to that result. In another
specimen other causes must be sought (see below).
The darker colour of the nearly transparent aragonite might be
due to its greater transparency if surrounded by opaque matter.
This assumption, however, is negatived by the fact that the
aragonite is really darkest where thinnest, that is, at the outer
boundary (11). The darkness is therefore due to contained darken*
ing matter — carbon. Quite apart from the fact that it is difficult
to account for the even dissemination of a heavy substance like
oxide of manganese in a vertical direction, the amount of manganese
indicated by a qualitative analysis seemed rather too small to fit
the explanation.
In the specimen of stone (fig. 2, p. 397), where the presence of
aragonite in the dark markings is not obvious (12), the markings are
quite as lustrous, or even more so ; this may be due to a darker
background of carbonaceous matter (12), to the finer polish which
the finer granules give, or to the actual presence of some aragonite ;
possibly to all three causes, more or less.
Whether aragonite was imperfectly formed in the first instance,
or has since been more or less degraded to calcite, seems a rather
unprofitable speculation, as the evidence appears equally favourable
to both theories ; the excessive amount of unoxidized carbon pointing
to the former, and the greater instability of aragonite pointing
rather to the latter explanation.
Digitized by Google
Vol. 50.J
MR. D. THOMPSON ON' LANDSCAPE MARBLE.
405
The alteration of colour in Vie outer layers of some specimens
appears to be a fairly common characteristic (7, 9, 12), for Edward
Owen several times refers to it (op. cit. pp. 169, 175) ; though
whether they are like this when first quarried or only become so
on exposure I cannot say : one would think the latter is the case.
The only interest attaching to this very common feature is that,
under the microscope, the change of colour appears to be confined
to the aragonite ; at least, it is so in my specimen (fig. 1, p. 395).
From this it would appear that any carbon present was slowly
oxidized, and iron and manganese only left as colouring matter, a
sufficient amount of these being present to colour the nearly trans-
parent calcium carbonate a light brown, although not enough to
colour the thin, opaque, white layer produced on ignition. There
is no difficulty in supposing these changes to have occurred, for the
discolouration some distance into the stone (7, 9, 12) shows the
possibility of water and dissolved gases penetrating thus far.
The thin veins of calc-spar (13) may have been produced at any
time posterior to the formation of the bed by ordinary desiccation
and subsequent infiltration.
The chemical composition does not suggest anything of importance
besides what I have already dealt with ; the phosphoric acid found
in the stone may, or may not, all have been introduced by the plants.
Some of it almost certainly was.
Till. Experiments made to reproduce the Characteristics of
the Landscape- Marble.
Supposing the explanations just offered of the origin of the
peculiar features of Landscape Marble to be true, it seemed probable
that they might be reproduced artificially. I therefore made the
following experiments.
(1) A rather wide glass tube was plugged at one end with a
mixture of fine sand and plaster of Paris ; over this was spread a
layer of ground chalk rendered dark by admix turo with oxide of man-
ganese, and on the top of all some very fine sand. The whole was
sufficiently porous to let water through gradually. On pouring dilute
hydrochloric acid into the tube effervescence occurred in the middle
dark layer, and bubbles escaped from the top, but there was no
noticeable rising of the dark layer to follow the bubbles of carbonic-
acid gas. It was not possible to get out the triple plug without
breaking it up, and another plan was adopted.
(2) The same materials were used as in the previous experiment,
but they were placed in a small flower-pot. The whole experiment
was conducted more slowly, and after its probable completion a
solution of carbonate of Boda was run through, with the idea that
some calcium carbonate would be re-formed, which would help to fix
any characters that had been developed. On taking the material
out of the flower-pot, I noticed (a) that the layers separated the
one from the other ; (6) that the dark matter had not risen into the
Digitized b/ Google
406 MR. B. THOMPSON 05 LANDSCAPE MARBLE. [Aug. 1894,
upper layer, although (c) the latter was full of tubes running in
various directions (but seldom straight up) through which the car-
bonic acid had escaped ; (d) that the tubes were comparable in size
with the dark arborescent markings of Landscape Marble, though on
the whole, perhaps, a little larger ; and (e) that the upper surface of
the upper layer was thrown into hills and hollows, with a small hole
at the centre of each depression, through which no doubt the last
bubbles of carbonic-acid gas had escaped as the material was setting
or drying.
(3) A glass tank was made, such as is used for showing chemical
reactions on a screen by means of a magic lantern, but made to leak
just a little at two opposite corners at the bottom. The lower part
was filled with very fine siliceous matter deposited from water, the
middle with precipitated calcium carbonate and carbon in the form of
lamp-black (both mixed well together before being poured in), and
over these some more fine siliceous matter. All being ready, dilute
hydrochloric acid was poured into the space above the various
sediments, but they now seemed to be impervious, and nothing
happened. When I made a connexion between the hydrochloric
acid and the dark layer by means of a long needle, the evolution of
gas was violent, and there was something like a miniature volcanic
eruption. Although not all that 1 hoped, two additional points of
evidence were gained : (a) there could be no mistake about the
carbon rising with the gas now— in fact, it was carried up so much,
and mixed with siliceous material from the sides of the vent, as to
form a half-cone, as it were, on each side of the crater ; and (6) a
mixed layer was produced above the siliceous sediment, in which the
dark matter (carbon) largely predominated.
I may mention that experiments in test-tubes generally failed,
because any slowly generated carbonic acid would lift a plug of even
rather coarse wet sand right out of the tube rather than bubble
through it. The production of a dome seemed a necessary pre-
liminary to breaking through, and in a test-tube the small superficial
area in proportion to thickness of sediment did not admit of dome-
formation.
Thus all the main features of the Cotham Stone, with the ex-
ception of the differences of mineral character and colour, have been
reproduced artificially.
IX. Conditions under which the Landscape Marble was formed.
To sketch imaginative pictures is perhaps more interesting than
the investigation of dry facts, but sometimes less profitable ; and
therefore, although I am about to draw a picture of the conditions
under which the Cotham Stone was deposited — as I seem to see it —
I do not attach as much importance to this part of the paper as to
the preceding pages.
Conceive a broad estuary receiving the drainage and fine sedi-
ment of a considerable area of flat fenland, by means of sluggish
rivers rising in somewhat higher calcareous lands also covered with
Digitized by Google
Vol. 50.]
MR. B. THOMPSON ON LANDSCAPE MARBLE.
407
vegetation.1 Sometimes the water would be chiefly derived from
springs within the watershed, and would contain very little sediment,
but being highly charged with bicarbonate of lime (as all limestone
springs are, particularly if derived from water firstly percolating
through decaying vegetable matter) it would deposit some of the
carbonate of lime on reaching the shallow and comparatively
stagnant water of the estuary, chiefly through loss of carbonic acid
consequent on higher temperature.
During a rainfall over the watershed the rivers would receive
surface-drainage, in addition to the clear supply from springs. This
would contain a considerable quantity of organic matter washed off
the surface, and particularly the already much decomposed vegetable
matter of bogs and natural ditches.
Thus there would be frequent alternations of nearly pure
inorganic matter and mixed sediment, sometimes the inorganio
predominating and sometimes the organic ; thus too the layers
would vary in constitution and thickness, forming the lower striated
portion of the stone. At these freshets also, no doubt, the greater
part of the argillaceous matter and grains of quartz, etc., would be
introduced.
, Now and again there would be a heavy rainfall and flooding of
the low-lying fenland, and then the streams would not only bring
much more sediment and organic matter than usual, so as to produce
thicker layers of dark matter, but they would by virtue of their
greater velocity and volumo tend to re-arrange the material recently
deposited in the direction of their course in the estuary, entirely
sweeping the bed of all recent sediment along certain lines, and for
a certain distance, and ro-depoeiting this matter farther out to sea,
or in lenticular masses at its side (16). For, where the rapid water
of the river touched the stagnant water of the estuary, strong
eddies or miniature whirlpools would be produced, into which
would be swept the matter (now more than usually organic) which
would otherwise have been spread in a thinner layer over a larger
area. These eddies thus would form traps for sediment, and,
according to the depth, sedimentation would proceed quietly below,
and lenticular masses would be formed (10). Outside the area of
the eddies the deposit would go on much as usual, the eddies them-
selves acting as screens for a time. Where the water was shallow
enough the eddies would also disturb the sediment around, and
so obliterate all traces of the original stratification, producing a
mixed layer not to be distinctly recognized as Cotham Stone (17).
Or possibly, in some cases, they would produce depressions which
1 4 From the frequency of such delicate creatures a* insect* in the Landscape-
stone, and in another band of limestone only a few feet higher, some of which
are said to be beautifully preserved, and could not have been long subject to
the action of the waves, it is supposed by Mr. Brodie that this part of the Lias
may have been formed in an estuary, which received the waters of some
neighbouring coasts, and which brought down the remains of insects and
plants.'— Herbert Ooss, quoted by Dr. H. Woodward in his paper * On a New
Lias Insect,' Geol. Mag. 1892, p. 195.
Digitized by Google
408 MB* B. THOMPSON ON LANDSCAPE MARBLE. [Aug. 1894,
would afterwards become filled up with other matter in the form of
lenticular masses.1
After the subsidence of the flood and the resumption of normal
conditions, for some time the waters would be more than usually
free from organic matter, owing to the washing that the land had
previously received, and the sediment would consequently make
purer limestone (8).a
Let us now consider what is happening in the dark layer whilst
this purer limestone is being deposited. The thicker dark layer
produced by the supposed flood would consist of vegetable matter
less decomposed than that normally brought down, and so under the
warm shallow water of the estuary it would continue to decompose,
and, like the black ooze from a dirty pond, give off bubbles of gas.
At first the bubbles passed off freely ; consequently they were not
very large, and having little or no sediment to lift could come off
anywhere, and so a great many spurts of dark matter were formed (8).
As the oalcareous sediment increased in thickness over the organic
layer the bubbles of gas escaped less frequently, from a smaller
number of points, and were larger ; for, before they could free
themselves from the sediment, they must havo attained sufficient
buoyancy to displace the material above them.
The bubbles in rising gave rise to three of the phenomena observed
in Landscape Marble:— («) they lifted somewhat the calcareous
matter contiguous to their path (8) ; (6) they relieved the pressure
behind, so that the dark matter which gave rise to them followed
more or less readily according to its plasticity ; and (c) the white
calcareous matter furnished the necessary pressure to cause the dark
matter to rise, and as a consequence filled the place from which the
latter was driven, thus becoming depressed between the arborescent
markings.
As sediment increased and tubes of organic matter were formed
in it, these latter themselves became centres for the evolution of gas,
and, having less material to lift, would discharge it more often, in
deviating paths — mostly, perhaps, in the first instance, through
relief of pressure at the side just when a large bubble escaped from
a neighbouring vent.
After a considerable time the decomposition of the organic matter
would be approaching completion, and three results would follow : —
(a) the organic matter left would consist chiefly of finely divided
carbon ; (b) the bubbles of gas would be few, large, and far between ;
and (c) when a bubble did escape it would produce vortex rings in
the water above, sufficiently powerful to disturb and re-arrange the
last layers of calcareous sediment, and well mix it with the black
carbon now filling and escaping from the tubes (9). (Layer Ft
figs. 1 & 2.)
Ultimately the escape of gas ceased, and layers similar to those
1 The specimen shown in fig. 2 (p. 397) appears to have been so situated that
it was peculiarly subject to disturbance ; both the lower and upper layers appear
to hare undergone re-arrangement of material.
2 The matrix in which the arborescent markings occur is much lighter than
any other part of the stone.
Digitized by Google
VoL 50.] MK. B. THOMPSON ON LANDSCAPE MARBLE.
409
found at the base of the stone were formed, though even then the
production of gas had not entirely ceased, and so the last layers of
plastic matter are uplifted in places, thus producing an uneven or
mammilla ted surface. To this result no doubt contraction of the
stone on setting contributed, particularly as it had a partly organic
and partly gaseous nucleus.
The subsequent changes, which resulted in the formation of ara-
gonite in some cases, and finor crystals of calcite only in others, must
be left unexplained for the present. We know that there would be
an aqueous solution of carbonic-acid gas under gradually increasing
pressure, and in contact with calcium carbonate which it is capable of
dissolving.
If the explanation which I have just given of the origin of
Landscape Marble be correct, we ought sometimes to find it in other
rocks and at other places where like conditions prevailed ; and there
ought to be grades of development. This really is the case (16, 17).
The EHhtria-bed in the upper part of the Rhcetic Beds at Garden
Cliff and Westbury-on-Severn, and several others, are mentioned by
Mr. H. B. Woodward as instances.1
One might be inclined to ask why we do not find these markings in
the sands and shales above coal-seams. Well, several circumstances
might prevent that. The sedimentation might have been too rapid, so
that the bubbles of gas were mostly imprisoned ; or the material might
have been coarse enough to let the gases pass between the particles
without disturbance of tho latter. But tho chief reason, I suspect,
was that the deposition of tho shales or sands was not tranquil
enough ; a very slight movement of the water in contact with sedi-
ment would facilitate the escape of gases and obliterate all trace of
arborescent markings. It may be, however, that these markings
might be found above some coal-seams — if specially looked for.
To the questions — (a) Can the arborescent markings occur with-
out the corrugated upper surface ? and (ft) Can the corrugated surface
occur without the markings ? — I should return in the case of the
former a negative, and in the case of the latter an affirmative
answer, for although a decomposition of organic matter and evolution
of gas sufficient to produce the arborescent markings could scarcely
fail to affect the sediment deposited just above, an intimate mixture
1 When this paper was nearly completed, through the kindnes* of Mr. H.
B. Woodward, I was permitted to see n specimen of limestone from the Purbeck
strata of Swanage (Durleston Bay), which in several respects resembles the
Cot ham Landscape Marble. It in very similar in colour to one of my specimens.
It contains peculiar dome-shaped markings, starting from nnd only above a
distinct, sharply -defined, dark layer of the same colour ; the upper surface is
extremely wrinkled, similar to Landscape Marble, only finer than the specimen*
of the latter that I have seen, and the bumps seem to correspond with the upper-
most domes of darker matter. It differs from Gotham Stone in being of coarser
granular structure, of different fracture (not conchoidal) ; the markings are of a
brown colour instead of being almost black, and they reach the surface every-
where, the thickness of the part of the stone in which thev occur being less than
i inch. I certainly think that this Purbeck stone had an origin similar to
that of the Cotham Stone, but, as the gases never had any difficulty in escaping,
decomposition was more complete — hence greater absence of carbon and more
general diffusion of the markings.
DigitizetLtif Coogle -«
410 MR. B. THOMPSON ON LANDSCAPE MARBLE. [Aug. 1 894,
of organic and inorganic matter might result in as great an evolution
of gas and uplifting of the layers above, although without being able
to produce arborescent markings.
Between the top layer of the White lias — the Sun-bed — and
Cotham Stone there are other beds presenting corrugated surfaces in
homogeneous limestone. These, I should imagine, contained organic
matter, although, on account of its being evenly disseminated in the
rock, its previous presence is not noticeable.
Discussion.
Mr. H. B. Woodward remarked that the Landscape Marble
occurred at the junction of the black Avicula con/orta-shales and
the White Lias, and exhibited a commingling of dark argillaceous
with calcareous sediment. Where the bed was persistent, it was
simply banded limestone ; where the arborescent markings were
present, the bed occurred in nodular and isolated masses, sometimes
4 feet or more across, and with the characteristic crinkly surface.
Thus he had concluded that the arborescent markings were produced
by irregular changes in the dark and pale muds during the solidifi-
cation of the stone. In illustration of the connexion between
arborescent markings and nodular and crinkly stone, he exhibited
specimens from the Purbeck Beds, and also from the Estheria-bed
(Rhaetic) of Westbury-on-Severn. The chemical and physical
aspects of the subject, he could not discuss, and that had now been
ably dealt with by Mr. Thompson.
Prof. T. Rupert Jones drew attention to what he thought was
the Rev. Osmond Fisher's suggestion of the cause of the arborescent
markings in the Landscape Marble. Among successive layers of mud
and tufa, in a marshy district, some of the thicker layers of rotten
plants gave way under the superincumbont tufa, which broke down,
and the carbonaceous mud was forced up along the lines of breakage.
The speaker thought that, by combining this with other hypotheses
already alluded to, we might find a true cause of the peculiar
markings in the stone.
Mr. F. A. Bather asked whether the drawing represented the
specimens the same way up as in situ.
Mr. Monckton said there could be no doubt that the mammillated
surface was at the top.
The Author said that he first of all desired to thank Mr. H. B.
Woodward for his forethought and kindness in exhibiting, by per-
mission of the Director-General of the Geological Survey, various
specimens of Landscape Marble and Purbeck Stone showing arbor-
escent and allied markings, in illustration of the paper. In reply
to Mr. Woodward's remarks he said that the chief reason for not
accepting his explanation of the arborescent markings was that the
shrinkage of the stone had not affected the contiguous thinner dark
bands ; although shrinkage of the upper layers had aided in the
formation of the corrugated upper surface. He also replied to
several questions, and more fully explained the results obtained in
experiments mado for the artificial production of the essential and
characteristic features of the stone.
Digitized by Google
Vol 50.] THE SYSTEMATIC T08ITION OP THE TRILOBITES. 411
26. The Systematic Position of the Trilodites. By H. M. Bernard,
Esq., M.A., F.L.S., F.Z.S., of the Huxley Research Laboratory,
Royal College of Science, Loudon. (Communicated by Dr.
Henry Woodward, F.R.S., P.G.S. Read March 7th, 1894.)
It is now just fifty yoars since Burmcister 1 wrote that he " was
convinced " that the reasons he afforded would be " deemed suffi-
ciently conclusive to satisfy the unprejudiced reader " that " tho
trilobites were a peculiar family of the Crustacea, nearly allied to
the existing phyllopoda, approaching the latter family most nearly
in its genus Branchipus, and forming a link connecting the phyllo-
poda with the poecilopoda." Burmoister's reasoning has not, how-
ever, been generally considered satisfactory, and his claim that the
trilobites are related to the phyllopoda, though recognized as possible,3
appears somewhat to have waned before the claim put forward
by others that they are primitive isopods. But this latter relation-
ship had already been shown by Burmeister to be highly improb-
able, and this judgment is fully endorsed and further enforced
by Gerstaecker, whose monumental review of tho Crustacea in
Bronn's 'Klassen und Ordnungen des Thierreichs ' gives special
weight to his opinion.3 In the absence of any certain knowledge as
to the character and arrangoment of the limbs, Gerstaecker, while
recognizing trilobites as Crustacea, declines to adopt any special
relationship : that is, he is evidently not convinced by Burmoister's
reasoning. And it must indeed be admitted that Burmeister's
arguments were, in themselves, far from conclusive, even when
correct as far as they went. Since the appearance of the 5th volume
of Bronn's 'Klassen und Ordnungen' in 1879, however, further
facts have come to light which completely justify the conclusions of
Burmeister, so far, that is, as to the trilobites having been primitive
phyllopods.
My own study of the phyllopod Apus brought me, from the
purely zoological standpoint and along an ontirely different line of
reasoning, to very nearly the same conclusion as Burmeister, or,
more strictly, to that adopted by Linnieus,* who decided in favour
of classing the trilobites with Monoculus Apus. I endeavoured to
show5 that Apus was the ancestral form of all existing Crustacea
(excluding the ostracoda), and, as such, might be expected to throw
light on the trilobites. About the same time as my book was
published there appeared a long and very valuable paper on the
1 ' Die Organisation der Trilobiten aua ihren lebenden Verwandten entvriekelt,'
Berlin, 1843. See also Engl, transl., edited by T. Bell & Edw. Forbes, Bay Soc.
1
3 Lane's ' Textbook of Comparative Anatomy,' English translation, p. 415.
* See further the note at the end on the isopod relationship.
* A summary of the different views which have from time to time been put
forward as to the systematic position of the trilobites is given by Walcott
in his short but invaluable paper : * The Trilobite : New and Old Evidence re-
lating to its Organization,' Bull. Mus. Comp. Zool. Harvard, vol. viii. (1880-fil).
» • The ApodicUe, a Morphological Study/ Nature Series, Macmillan, 1892.
Digitized by Google
412
MR. H. M. DEKXARD tiX THK
[Aug. 1894,
genealogy of the Crustacea 1 from the pen of Prof. Carl Grobben, of
Vienna, whose well-known researches into the anatomy and embryo-
logy of the Crustacea lend special weight to his conclusions. Prof.
Grobben, after reviewing an immense array of facts and arguments,
arrives at the conclusion that all the existing Crustacea can be
deduced from an Apus-like ancestral form.
Since the publication of these conclusions, I have been studying
the organization of the trilobites themselves, and I wish here
to express my warmest thanks to Dr. Henry Woodward, F.R.S.,
to Prof. Judd, F.R.S., and to Prof. G. B. Howes, for kindly placing
specimens at my disposal for examination, and further to Mr. W. I.
Last, Keeper of the Mechanical Department at the South Kensington
Museum, for the kindly and invaluable assistance he rendered me
in fitting up for me a small sandblast, by means of which I have
been endeavouring to * develop ' the fossils.
I. Tho great variability in the number of the segments shown by
the trilobites need hardly be again insisted upon as a feature con-
necting them with the phyllopods. Of still greater importance is
the gradual diminution of the size of the segments posteriorly,
which remarkable feature the trilobites share with Apus. I have
endeavoured to show (op. jam cit.) that this feature is explicable by
assuming that Apus is the ' Protonauplius ' of authors, in which a
very large number of segments commence to develop, many of
which, however, at the posterior end of the body, remain fixed in a
rudimentary condition. This explanation of the morphology of
Apus is, it seems to me, evident if we compare the adult with the
developing larva. Tho adult is but the grown, not metamorphosed,
larva — grown by the continual development of segments from before
backwards, until at a certain stage this process becomes fixed, and
we have the adult Apus with a number of fixed rudimentary
segments.9 This fixation of a number of undeveloped segments is
visible in many trilobites.
In tho early Olenellus these rudimentary postorior segments are
still free (t. e. do not form a pygidium). As a rule, however, they
form the plate-like pygidium characteristic of the trilobites. This
specialization Beems to have set in very early ; for instance, in Micro-
discus we find a pygidium apparently consisting of only a few
segments differing little in size from those of the trunk, whereas
a review of the pygidia of the whole order leaves little doubt that
this organ was originally composed of a number of larval segments
which diminished gradually in size and development from before
backward.
That animals closely resembling Apus were extant in earliest
1 Sitzungsber. d. k. Akad. Wissensch. Wien, vol. ci. (1892) pt, i. pp. 237-274.
3 In a recent systematic paper on the genus Apu* (Z. w. Z. 5, pt. 1),
Dr. Broem records a remarkable inconstancy in the number of limbless tail-
segments within one and the same species. In A. cancriformis the number
varios from 5 to 8; in A. numidicus from 10 to 14 ; in A.productus from 4 to 6;
in A. extcrntts from 6 to 6. This fact is quite in keeping with the undifferen-
tiated (that is, embryonic) condition of the posterior region of the body.
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION OP THE TRILOBITF.S.
413
times we now know for certain, not only from the existence of rich
remains of phyllopods with shields closely resembling that of Apus.1
but further from the remarkable Cambrian Protocaris Marshi'1
(tig. 1), which apparently possessed the same peculiar character of
the posterior segmentation as Apus, and which 1 should like to
call Apus Marshi.
Again, the extinct Echinocaris Fig. 1.— Protocaris Marshi,
takes its name from a feature Walcoti.
which it possessed in common
with Apus. The posterior cylin-
drical (and apparently limbless)
segments are provided with a
ring of spines slightly anterior
to the posterior edge of the seg-
ment. Serrated posterior edges
of these segments occur very
generally in the copepoda, and a
variation of the arrangement iu
Echinocaris occurs in some stoma-
topoda, and perhaps on the dorsal
sides of other Crustacea (not
phyllopods). It is, however, very
marked in the phyllopods Apus
and Estheria, in the former of which it repeats almost exactly the
arrangement in Echinocaris, there being a complete ring of sharp
spines round each of the posterior segments, slightly in front
of its posterior edge. In both Echinocaris and Apus, further, this
special ring of spines is not developed on the anal segment.
Moreover, the shell of Echinocaris has lateral markings which in-
voluntarily suggest the markings caused by the shell-gland on the
carapace of Apus. In addition to two caudal cirri, Echinocaris had
the median prolongation of the anal segment which is character-
istic of so many of the Apodidae (Lepidurus).*
II. The formation of the head by the gradual incorporation of
trunk-segments is now very clearly shown in Walcott's detailed
description of the Cambrian trilobites of North America. The
composition of the head out of five somites is, as is well known,
a crustacean characteristic, although no crustacean now shows this
1 See ' Monograph of the British Palaeozoic Phyllopoda,' pt. i. T. R. Jones
and H. Woodward, Pulieont. Soo. 18H8. See also the paper by Clarke(* American
Naturalist,' 1893. p. 793) on the carapace of Iikinwari*. It seems to ire that
the remarkable double suture which he describes for this interesting Devonian
crustacean points back to the univalve condition of the original carapace. It
it> easy to deduce both forms of the carapace, that with a single median, and
that with a double suture, from an Apus-MVe shield ; whereas it would be
difficult to arrange tbes»e carapaces in any other order of development.
* Walcott, ' On the Cambrian Faunas of North America,' Bull. U.S. Geol.
Surv. No. 10, vol. ii. 1884-1885.
1 8ee James Hall's figures, ' Natural History of New York.' pis. xxii.-xix.
vol. vii. (188H).
Q. J. U.S. No. 199. 2f
Digitized by Google
414
MR. H. M. BERNARD ON THE
[Aug. 1894,
primitive segmentation of the head-region. It is even quite
obscured in A pus, and can only be gathered from the number of
cephalic appendages.
The head-region of the trilobites is also, as a rule, so specialized
that it is no longer possible to make out its exact segmentation.
Although five seems to be the usual number of component segments,
four forming the glabella, and the fifth the * occipital ring/ trilobites
occur in which all traces of segmentation have disappeared from the
glabella, while again, on the other hand, others appear to have six
segments forming the head. Barrando has tabulated the apparent
segmentation of the heads of the Silurian trilobites of Bohemia
(vol. i. pp. 195-7). The numbers range from 2? to 6. There is
no reason why the trilobites should not show great variation in the
number of the segments composing the head ; indeed, the conclusious
at which we have arrived concerning their systematic position
would lead us to expect such variation. Fortunately, in the ancient
Cambrian forms, such as Microdiscus and OUneUus, the segmentation
of the head is so clear that it is almost impossible to misunderstand
it. A study of these forms seems indeed to show us the crustacean
head in making.
Commencing with Microdiscus (fig. 2), we find that it has only
four distinct segments embraced
by the head-shield. The fourth Fig. 2.—Headshitld of Micro-
segment, further, shows traces
of quite recent incorporation
into the head (see fig. 2, profile).
So that this form points back
to the time when there were
only three segments forming
the head-region. There are
other trilobites with apparently
only four segments in the head
(e. g. Triarthrus Beckii), which
on that account ought, perhaps,
to be classed with Microdiscus
as a group distinct from those
with five segments. On the
other haud, many trilobites with five head-segments show signs of
having arisen from those with only four head-segments, inasmuch
as the fifth very often bears the appearance of having been recently
incorporated; it frequently retains its strong resemblance to the
trunk-segments, and is seldom completely merged with the glabella.
We may, then, safely conclude from the study of adult forms
alone: (1) that Microdiscus was preceded by a form with three
head-segments ; (2) that forms with four head-segments, of which
examples such as Microdiscus have been preserved, preceded the
forms with five head-segments; (3) that forms with six head-
segments {Ogygia and the related Limulus and Eurypterids) are
to be derived from those with five head -segments.
The formation of the head-region by the fusion and gradual in-
discus Meeki, showing head of
four segments, the jouith only
partially incorporattd in Uie
head.
[From WalcoU, Tenth Report U.8.
Gool. Surv. (16U0) pi. Ixxxi.J
Digitized by Google
Vol. 50.] SYSTEMATIC POSITION OF THE TRILOBITES. 415
corporation of somites, which is quite obscured in the development
of the Crustacea, is still perfectly clear iu the development of the
trilobites, e. g. in that of Olcncllus described and figured by Walcott.1
This trilobite, with five head-segments in the adult, arose almost
certainly from a form with four head-segments ; the youngest stage
observed has only four segments, with their own characteristic
pleurae, the posterior pairs being bent backward, as terminal pleura
usually are (fig. 3). When the fifth head-segment appears, it does
so as a trunk-segment, i. e. with typical trunk-pleura; that is,
with pleura which run out laterally in the transverse plane (see
figs. 4 & 5, p. 416). These pleura of the fifth head-segment only
gradually become incorporated into the head-shield, and in some
species their points seem to persist on each side in the middle of tho
posterior margin of the cephalic shield.
These figures of tho developing OUneUus are further of special
interest because they show without doubt that the segmentation of
the head was still very distinct,
t. e. the fusion of the segments Fig. 3. — Youngest stage o/Olenel-
was only of recent occurrence. lus asaphoides (± mm.) seen
We find the head -segments by Walcott.
diminishing in sizo from front
to back (fig. 4 a, p. 416), which
is typical of the development of
segmented animals when the
segments do not belong to a
highly specialized region. This
early developmental stage no
longer appears in the metamor-
phoses of the Crustacea.
It appears to me, then, that tThi8 .^0*8 four bead-segments
, rr. ., I ■ ... with the anul segment ; the repha-
we have, in the trilobites Micro- lio ,hield |>anmtlj con8iflt9 Gf tho
dtscus and Olenellus, two cod- pjeurae of the l0t-4th segment*.]
secutive stages in the develop-
ment of the crustacean head. But, at the same time, although
Microdiscu9i with its head of four segments, is, in this respect, an
older type than OleneUus, with its head of five segments, in other
respects (for example, in its pygidium) it is more specialized.
III. The two chief characteristics of the head of these primitive
Crustacea are (1) the bending round ventrally of the first segment,
so that the labrum and mouth face posteriorly ; and (2) the cephalic
shield.
1. In my endeavour to trace the possible origin of the Crustacea
from their anneli lan ancestor, I laid special stress upon this bending
round of the mouth for the purpose of using the parapodia as mouth-
organs. I had shown, at first without reference to the trilobites,
* 'Fauna of the CHenel/us-zone' (see especially pi. 4, xwvi.) in U.S. Geol.
Surv. Tenth Report (1890). See also S. VV. Ford, ' Embryonic Forms of Trilo-
bites,' Aiuer. Juurn. Sci. ser. 3, vol xiii. (1877) p. 266, and vol. ixii. (1881)
p. 250 ; some of Walcott's figures are taken from the»e papers.
2r 2
Digitized by Google
416
MR. H. M. BERNARD ON THE
[Ang. 1894,
and solely from an examination of the external and internal
structure of Apus, that such bending round must have taken place
in the ancestral crustacean (4 The Apodida?,' op. supra cit.). But,
having only Apus as a guide, I had to leave the question undecided
as to how many segments actually turned over, i. e. into or towards
Fig. 4.— Olenellus asaphoides, after Ford.
e ha
[The order has been accidentally reversed.]
a = Embryonic form : head composed of Ave segment*, which diminish in sire
from before backward.
b — A further stage of the same.
c= Pleurae of the fifth segment beginning to take part in the formation of the
the horizontal plane. Finding the mandibles (belonging to the
third segment) arranged dorso-vent rally, I have since been inclined
to think that the third segment remained more or less completely
in the transverse plane. I should therefore have assigned the chief
part in the formation of the bend to the first and second segments.
A study of Olenellus, in which the segmentation of the head is
especially distinct, shows us that such a bending round did actually
take place, but that it was primarily confined to one, t. e. to the
first, segment. By the bending
Fig. 5. — Young specimen of
Olenellus asaphoidc
round of the first segment, so
that the labrum and mouth
point backward, thus apparent
in the trilobites, we can, as I
have shown, obtain an expla-
nation of the prc-oral position
of the antennae in the Crustacea,
and, further, of the bend in the
alimentary canal also charac-
teristic of the group, and espe-
cially marked in Apus and
lAmulus. In this latter animal,
indeed, the backward bend of
the oesophagus has been second-
arily exaggerated. The same may also havo taken place in
Apus. If so, it must be attributed to the gradual backward growth
of the mouth, so as to allow a greater number of limbs to function
as mouth-parts. In Limulus the basal plates of five pairs of limbs
[Tbe pleura of the fifth head-segment
are seen to resemble those of the
trunk-segments.]
Digitized by Google
Vol. 50.] SYSTEMATIC POSITION OP THB TRILOBITES. 417
function as jaws, a specialization further developed in the Eury-
pteridae, in which the most posterior of these becomes the most
powerful.
The great development of the glabella in many trilobites may
perhaps be due in some cases to the great development of the
oesophagus as a * masticatory stomach/ or, again, of the mid-gut
diverticula ('liver'), which almost certainly occupied this part of the
body (cf. Limulus and Apus).
My theoretical deduction of all Crustacea from an annelid in
which the anterior end was bent round ventradly, so as to allow of
its appendages to function as jaws, is thus fully confirmed by these
early trilobites.
2. The head-shield seems to have been a characteristic of all the
earliest Crustacea. I endeavoured (in * The Apodidae ') to explain it
as starting from the lateral projections
which would be necessarily caused by ^ig. 6.— 8ao hirsuta, after
the sharp bending round of the first Barrandt.
segment. A careful study of the
series of under-surfaces of the heads
(especially of Dalmanites socialu and
ParadoancUs bohtmicus) figured by
Barrande 1 has confirmed me in this
supposition. [Rwly „tage, showing Intend
Still more conclusive evidence, projectionsaa due to bending
however, on this point is yielded by of firet tegment.)
the developmental history of Sao
hirsuta, also given in Barrandc's classical work. Stages 1-8 show
the first segment produced on each Bide into points curving back-
wards round the outer edges of the cephalic shield (see fig. 6).
In stage 9 this is nearly obscured, while the bead- shield of the
adult is very highly specialized and shows no traces of its origin.
The head-shield thus almost certainly originated in the first
segment, as a pair of lateral projections due to the sharp bend in
that segment. The backward growth of these projections, i. e.
their repetition on the following segments as pleurae, was a natural
process.
In Microdiscu* the head-shield extends backward through three
segments, the fourth segment being not yet quite incorporated into it.
When five segments became definitely fixed as the normal number
of head-segments, the head-shield ran hack to the posterior edge
of the fifth segment. Not only, however, does this fifth segmont
often appear like a trunk-somite, but the transverse strip of the
head -shield belonging to it very often appears, as above noted, to
be a pair of pleurae belonging to the trunk-segments, fused along
their anterior edges with the cephalic shield.
This fact, namely, that the comparatively recent incorporation of
the pleurae of the fifth head-segment is still visible, helps us to under-
stand the morphology of the head-shield. As above suggested, wo
Sytteme silurien de la Bobeme.' vol. i. (1852) Trilobites, pit. 2 a and 2 a,
i •
Digitized by Google
418
MR. It. M. BERNARD OS IIIK
[Aug. 1894,
may safely describe it as consisting of the fused lateral projections of
the cephalic segments. The first pair, I think, were the lateral pro-
jections which would naturally bo formed by the bending round of
the first segment. This first pair of projections would give rise
to a second pair belonging to the second segment. I say 4 would
give riae ' because, from the method of development of segmented
animals, the metameric repetition of special structures is a well-
known fact. "We can thus suppose three pairs of ' pleurae,'
diminishing in size, developed on the 2nd, 3rd, and 4th segments
Fig. 7. — Diagram thawing the probable composition
of Hit head-thiekl.
as metameric repetitions of the lateral projections of the first
segment. This stage seems indeed to be represented in the larval
OUnellus (fig. 3, p. 41.5), in which we have the head-shield composed
of the secondarily enlarged lateral projections of the first segment,
and three pairs of pleurae. These posterior pleuno of the posterior
developing head-segments slope directly backward, just as do the
pleura? of the posterior tail-segments, which are also rudimentary.
I consider this latter point of great morphological importance, as it
seems to show that the head-shield was a structure sui generi*.
This head-shield, composed of the pleurae of four segments, in the
same way gave rise in the trilobites to large pleurae on the
subsequently developed trunk-segments, these pleurae generally
diminishing in size from front to back. If the first pair of these
pleura? fuse with the head-shield, as above described, we should get
a head-shield composed of ( 1 ) the lateral projections of the first
segment, (2) the pleura? of the second, (3) the smaller pleurae of the
third segment, (4) the still smaller pleura} of the fourth segment,
(5) the pair of the large pleurae of the most recently incorporated
trunk-segment forming the filth cephalic segment. This origin is
further illustrated by the diagram (fig. 7). That diagram finds ample
justification in the series of figures 3, 4, 5, and 6, in which we trace
the rise of the fifth cephalic segment, with the gradual develop-
ment and incorporation into the head-shield of its pleurae, which
are typical trunk-pleurae.
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION' OF THE TKILOBITES.
41?)
It is farther of especial interest to note that the lines of fusion
between the lateral projections of the first segment and the pleura
of the second segment apparently correspond with the posterior
halves of the mysterious cephalic sutures. Many trilobites have
these sutures running out laterally, as if dividing the shield into
two somewhat similar pleura (e. g. Cromus interco»talu* and Dal-
m mites).1 The symmetry of the line itself has, however, been
broken by the wandering backwards of the eye-tubercle, which, as
we shall see, belonged originally to the first segment, and wandered
only secondarily on to its lateral projections. The larval forms of
Olenellus (fig. 3, p. 415) show how this line might run almost
straight backwards when the first pair of projections are very
largely developed in comparison with the pleurae of the following
segments, which, like the pleurae of the rudimentary tail-segments,
may slope backwards.
The retention of the line of fusion 2 between the anterior edges of
the pleurae of the second head-segment with the lateral projection!*
of the first segment, as a line of weakness through the thick dorsal
head-shield, may have been useful for ecdysis. The thin ventral
membrane would no doubt have split easily ; but, for the drawing out
of the limbs, etc., it is necessary to open up the dorsal surface.
This would have heen extremely difficult in the case of the trilo-
bites, unless special provision had been made for it. Both Limulus
and Apug are said to moult by splitting along the frontal edge.
In the trilobites, the splitting generally appears to have left the
frontal edge on each side of the glabella and to have run back to the
eyes ; it then followed the line along tho inner posterior edges of the
eyes, which, as above stated, may well have been the original line of
fusion of the first and second pairs of pleurae forming the head-shield.
IV. In endeavouring to deduce Apia from a carcivorous annelid,
by the bending round of the first segment. I had assumed that the
eyes were originally on the prostomium (as they are typically in
carnivorous annelids), and that when this was bent round ventrally
they wandered up on to the dorsal surface of the first segment.
Clear traces of this wandering of the eyes from the ventral on to
the dorsal surface can still bo found in the development of Apu-%
the eyes showing a gradual dorsal displacement during development.
I brought forward also some morphological evidence in favour of
this dorsal wandering of the eyes of Apus : for instance, the position
and shape of the brain and antennal nerves seem bost explained on
the assumption that the brain had been dragged out of its originul
1 An almost similar suggestion was made by M'Coy. 'On the Cla*sificatit;u
of some British Fossil Cruwtacea,' Ann. A Mag. Nat. Hist. ser. 2. vol. iv. 18W,
who concluded, from the position of the eyes as belonging to the first 'ring.'
that the suture running posterior to them was the line of junction of the first
and second rings. He claimed the whole sutures as such. I would, however,
only claim the posterior portions of the suture, believing that the auterior lobe
of the glabella certainly belongs to the first segment.
J S.W. Ford, Am. Journ. Sci. ner. 3. tol. xiii. (1877) p. 2<V7, if I understand
him aright, states that this fusion is incomplete in the youngest stages.
Digitized by Google
-120
MH. H . M. BERNARD OX TH I
[Aug. 1894,
prostomial position (which has been retained in Lintulux) by such a
movement of the eyes. I further thought that the water-sacs over
the eyes of Apus might be evidence of this wandering, these water-
sacs being perhaps the integumental fold round the base of the
prostomium, which had been drawn back into pockets by the eyes,
in which pockets the eyes were consequently situated (fig. 8, p. 421 ).
This sinking-in of the eyes into pockets under the cuticle has been
shown by Grobben to be very common among the lower Crustacea.
It is found in the Cladocera, Estherida), Argulus, and in the larval
cirripcdes, and must, therefore, be considered of very remote origin.
In comparing the eyes of trilobites with those of Apus, the
following points are noteworthy : —
(a) The eyes, in most trilobites, are found at varying distances
from the glabella, on the 4 cheeks' of the head-shield. Olenellu**
however, shows that the eyes originally belonged to the glabella, and
further, to the first segment. The ocular tubercle in OlenelUat is seen
branching off from this segment and bending round backwards along
the posterior edge of the pleurse of the first segment (see figs. 4 & 5,
p. 416). The eyes never cross the great cephalic sutures.
(6) The fact that, in the trilobites, the eyes wandered laterally
off the glabella (which is shown also in the development of Sao
hirsutn ') and took up the most varied positions on the 1 cheeks ' of the
cephalic shield, seems to show that they had no fixed hereditary locns
011 the dorsal surface.
(c) Many of the early trilobites, e. g. Parado.vide*, show, in
addition to the four more or less clear segmental constrictions between
the five eegments composing the head, traces of a constriction lying
anteriorly, on what is apparently the first segment. If this was a
true segmental constriction, then, in these cases, we should have six
segments forming the head, which, it must be admitted, is a possible
variation. The head-region of Ogygia is apparently, and of Limulus
is certainly, composed of six segments ; and the secondary fusion of
the anterior trunk-segment with the typical number five is what
we might expect from the whole process of the formation of the head
out of fused segments. But there is another interpretation which
requires no more than the normal five head-segments, namely : these
anterior infoldings are the openings into pockets into which the
eyes have sunk beneath the outer cuticle, pockets homologous with
the water-sacs over the eyes of Apus. It is true that in Apvt
the pore opening into these sacs is unpaired and median. The
paired condition of the pores in the trilobites might be due to
the wandering apart of the eyes laterally, which has so evidently
taken place (cf. Olenelhts). These infoldings in the trilobites are
nearly always found in a direct line with the eyes, and seem ulti-
mately to disappear from the glabella of later trilobites. I would
like to suggest, further, that the pores found just in front of the
eyes of some trilobites J (pi. xxiv. fig. 30, Barrande), or in the
' KorscheM ft Heider, ' Vcr<;l« i' bendo Entwickelungage*ch.' 18i>2. p. 512.
■*ee Woodward, 1 On the Nature of certain Pore* otwervable in the Ophulnn
or Head-shield of tome TrilubiU t>,' A pp. to Monogr. in Paheont. Sou. vol. uxviii.
ISM.
Digitized by Google
Vol. 50.]
8YSTKM AT1C POSITION OF TUB TRILOHITKS.
421
furrow between the glabella and ebeek in trilobites which appear
to be eyeless, may be the same structures, only closer to the eyes.
Perhaps too the curious marks on each side of the glabella in
Phacops Volborthii and Ph. fecundu* may also come under the same
head : that is, they may all be openings, or the remains of openings,
into water-sacs over the eyes.
(d) According to this interpretation of the facts, water-sacs must
have originally been present over the eyes of all these primitive
Crustacea, completely
degenerating, however,
in later forms. The tri-
lobites afford some inter-
esting, though indirect
and not conclusive, evi-
dence on this point.
As is well known, in
the earliest trilobites
the ' eye-membraue ' is
generally wanting.
Gerstaecker1 would ac-
count for this as due to
the enormous pressure to
which the Lower Silurian
fossils were exposed. I
would suggest, as a more
probable interpretation, that the eye proper was not in actual
contact with the outer cuticle, but "lying in a pocket which would
fall away from the outer cuticle as the animal tissues decayed. In
Apusy the eye, not being attached to the outer cuticle, but belonging
to the thin cuticle of the water-sac (see fig. 8), easily falls away from
the former in the process of section-cutting ; only as the water-sacs
degenerated (as they have done in the higher Crustacea), and as the
eyes became secondarily attached to the external cuticle, would they
be preserved.
We may, then, suppose that in the earlier trilobites the external
cuticle was differentiated, above where the eyes were situated in
the water-sacs, so as to form a kind of thin and membranous cornea,
which would be easily destroyed. This would explain the frequent
collapse of the 4 eye-membrane/ Again, in other trilobites, the
external cuticle above the eyes may have shown no such differentia-
tion into a smooth membranous cornea, the eyes lying in the water-
sacs under a generally transparent cuticle. These trilobites would
now appear to havo been blind, whereas their eyes were more
probably in pockets under the external cuticle. Microditau has no
eyes visible. It is interesting to note M'Coy's observation (quoted
by Dr. Woodward, op. supra cit.) that the pores above mentioned are
most obvious in ' blind ' trilobites.
(e) The eyes which do appear in trilobites show very marked
differences, which Burmeister, with groat ingenuity, endeavoured to
1 Bronn's 'Klassen und Ordnungen,' rol. t. p. 1168.
Fig. 8. — Diagram of the eye of Apus.
[The eye w sunk beneath the surface in a
venter-sac, and is therefore not in contact
with the ouler outicle ]
Digitized by (Google
422
MR. JI. M . FF.H5AKD OJf THB
[Aug. 1894,
show miprht be dnc to the presence or absence (presumably through
post-mortem destruction) of a thin membranous cornea, which he
assumes covered the eyes of the trilobites, similar to that which
covers the eye in Bmjichipus. I have always considered this mem-
branous cornea of Branchipus as indicatory of the former presence
of a water- sac, which secondarily disappeared as the eye became
stalked ; otherwise it seemed difficult to explain why the eye itself
did not belong to the external cuticle represented by the cornea.
In the same way, among some of the later trilobites, the water-sac
probably degenerated secondarily, leaving the eye in contact with,
but not strictly belonging to, the outer cuticle, which may have
covered the eye like a thin membrane. This whole subject is,
however, beset with great difficulties, so that it is irojiossible as yet
to come to any definite conclusion : for while, on the one hand, the
so-called faceted eyes of trilobites, showing round projecting single
eyes arranged at some distance from one another, remind one
strongly of the tips of crystalline cones,1 such as occur in the eyes of
A(mb (see fig. 8, p. 421), on the other it is clear from Clarke's*
researches that these were certainly in some cases true corneal
lenses, apparently belonging to the outer cuticle, and, iudeed,
somewhat elaborate structures.
Further, the eye of Limulu* is a great difficulty ; here we have
no trace of a water-sac, nor of corneal lenses, w hile the bodies
which appear antilogous to the crystalline cones are simply inward
projections of the outer cuticle. In discussing the eye of Apus, I
was led to the conclusion that the eye of Limulus was the more
primitive, a conclusion also arrived at by Watase.3 If this is so,
then these eyes certainly belong to the external cuticle primarily,
and not secondarily by the degeneration of a water-sac. The only
way out of the difficulty, it seems to me, is to assume that while, in
some cases, the eyes, in travelling backwards, passed beneath a fold
of the cuticle into deep pockets, as above described, in others the
folds themselves degenerated secondarily, leaving the eyes once
more on the free exterior surface of the head.
V. Behind the eyes of A put there occurs, in all species of the
Apodidae that 1 have examined, the well-known 'dorsal organ,'
which in Apus appears to be an excretory organ.4 It is often raised
on a slight plateau above the surrounding cuticle ; the cuticle of the
plateau itself is extremely thin, and likely to collapse easily during
the early stages of fossilization. Did such an organ occur on the
dorsal surface of the head of the trilobites? Fig. 9 (p. 423) shows
us that, in the Cambrian trilobite Olenellu* asapTwidtB, there was such
an organ, of essentially the same shape as that in Apus, but apparently
shifted farther back than in ApuB, that is, on to the fifth segment. In
' 8ee Packard, ' The Structure of the Eye of the Trilobites/ in the ' American
Naturalist' for 1880.
3 ' Structure and Development of the Visual Area in the Trilobite Phacops
liana. Green,' Joum. Morph. toI. ii. (1889).
* ' Morphology of the Compound Eve* of Arthropods/ Journ. Roy. Mier.
Sue. 18fl(),p.3l8.
* ' The Apodida-/ p. 304.
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION OP THE TRILOBITES.
423
Aput its exact position with reference to the segmentation is difficult
to ascertain. As some evidence of this wandering backwards of the
organ in the trilobites, I would draw attention to the sloping back-
wards of the lines of constriction between the posterior head-segments
shown in fig. 9 ; and further to the fact that Walcott describes a
tubercle on the fourth (last) head-segment of Microdiscus, whereas,
where five segments form the head, it is generally found on the fifth.
Asaphus seems to form an exception, for the tubercle (?) appears to
occur on the fourth segment, and not on the fifth.
Fig. 9. — Head-shield of Olonellus (Meaonacis) asaphoides, showing
tlte oval ' dorsal organ' on the fifth cephalic segment.
[From Tenth Report U.S. Geol. Surv. (1890) pi. xc]
This organ seems, in the trilobites as in the Crustacea, to have
been very early modified. It develops in the former into a slightly
conical prominence in Jsotelus, or into a long sharp spine, e.g. in
Olenellus Broggeri. Traces of it appear in very many Cambrian and
Silurian trilobites, for example, in species of JJtdmanites^ Asaphus (on
the fourth segment), Vheirurut, Bronteus, Proettts, Cyphaspis, Acid-
aspis (either as a median spine or as a circumvallate pit between
two lateral spines), Conocephalites^ Hydrocephalus. In the Carbo-
niferous trilobites figured in Dr. Woodward's monograph,1 traces of
it are marked in species of Phillipsia and G rijfithides. In many of
these it occurs as a round mark, the exact nature of which is difficult
to ascertain. In Olenellus Broggeri and in some species of Sao and
Acidaspis, as above stated, it is produced into a sharp median spine.
That all these structures are modifications of the oval patch on the
1 Palwont. Soe. vols, xxxvii. &, xxxviii.
OO
(
424 MR. H. M. BERNARD ON THE [Aug. 1894,
head of Olenettus there can, I think, be no doubt, and as little, all
things considered, that this oval patch on the head of Olentllus a*a-
phtrides is homologous with the oval patch on the head of Apus. If so,
it was, in all probability, originally excretory, and its transformation
into a spine suggests that this spine was poisonous. It is, further,
interesting to note that this median head-tubercle or spine tends to
be repeated on the trunk-segments.
VI. The alimentary canal of the trilobites, as is well known, has
been found more than once as a cast within the animal, due, *
according to Barrande,1 to its having been filled with argillaceous
matter, which suffered no change if the matrix of the fossil happened
to be sand. In this connexion, I
might mention that I have a series
of sections of Apu* cancriformis in
which the alimentary canal is full,
almost to distension, of fine grit.
Burmeister, arguing from analog)',
placed the anus of the trilobites
terminally, as indeed he was quito
justified in doing, considering that
ho correctly interpreted the pygidium
as composed of fused segments. 1 do
not quite understand the figure given
by Burmeister (op. ext. pi. v. fig. 4),
which seems to represent an anal
aperture in Asaphus tyrannus. If
this be so, the anal segment in this
animal seems to be greatly specialized,
and the position of the aperture
figured (on the ventral surface of the
segment) may have been secondarily
acquired. I have myself discovered,
by means of the sand-blast, clear
traces of an anus in Calymene Blu-
menbachii (see fig. 10, a&l>\ and it is
situated terminally, as one would
expect. This position of the anus
could further be gathered from what is known oi me course oi rue
alimentary canal. Barrande (p. 229) describes it as running
backwards " jusqu'a l'extremite de l'axe, vers le bord posteriour du
pygidium."
VII. With regard to the limbs of the trilobites, the most important
recent discovery 2 has been that of antenna) in Triarthrus Btckti
1 'Systeme silurien de la BoMow/ vol. i. (1852) p. 229.
* W. D. Matthew, 'On Antenna? and other Appendages of Triarthmn
Becfcii; Amer. Journ. Soi. ser. 3. vol. xlvi. (1893) p. 121. By the kindnes- of
Dr. Henry Woodward I have been able to examine a specimen with antenna* ,
presented to him by Prof. Mursh and exhibited by him in the Natural
II t..t\ Museum at South Kensington. I have no word to add to Mr. Matthew's
careful description.
Fig. 10. — Pygidium of
Calymene Blumen-
bachii.
a = Under surface, showing
the torn edge of tbe ven-
tral membrane running
posteriorly towards tbe
median anuB.
6= The same, as first re veaU-d
by tbe Band-bliu»t. Tbe
projecting portion of tbe
membrane bounding tbe
anuB anteriorly was acci-
dentally broken oft".
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION OF THE TEILOB1TES.
425
(fig. 11). These antennae, as far as can be ascertained, were attached
on each side of the labrum,1 and may be assumed to have belonged
to the first segment, that is, they were homologous with the first
antennas of Apus. These very pronounced antennae were evidently
specialized in this particular trilobite ; but we may naturally infer
from them that all trilobites had appendages on the first segment
which were, as a rule, sensory organs. The exact form which they
aesumed is a matter of little morphological importance. In some
they may have developed
pincers (cf. Limulus and Ptery-
yotus'*), but in the majority
of cases they more probably
remained purely sensory.
As to the appendages of the
following head-segments, we
should probably find every
grade of specialization, from the
lowest trilobites upward. The
simplest would be that stage
in which the head-appendages
did not differ either one from
the other or from those of the
trunk : all alike being, in
all probability, membranous
lobes deducible from the para-
podia of their annelidan ances-
tors. The ventral portions of
these were, in all probability,
masticatory ridges, and pre-
eminently specialized as such
in the region of the mouth.
Dr. Woodward's discovery of
one of these head-appendages
in Asaphua platycephalus *
shows the basal masticatory
ridge, while the dorsal portion
is developed into a jointed
cirrus-like process (cf. Plery-
gotus). In some trilobites all
the four pairs of posterior cephalic appendages may have pre-
sented this character, the masticatory plates being about equally
developed (as in Limulus\ whereas the dorsal portions were either
sensory organs or walking-limbs. The great interest which attaches
1 [While this paper was passing through the press, a paper appeared by
Wnlcott, 'Note on some Appendages of the Trilobites,' Qeol. Mag. June 1894,
p. 246, which contains a figure of a IViarthrut, showing the attachment of these
antennas in exactly the position which the first antenna? occupy in Apu*. As
to the great importance of this, see my note in 'Nature,' vol. xlviii. (1893)
p. 582.— H. M. B., June, 1894.]
3 And, according to Laurie, Slimonia, 'The Anatomy and Relations of the
Ellrvpterida^, Trans. Roy. Soc. Edin. toI. xxxvii. pt. ii. (1893) p. 009.
3 Quart. Journ. Geol. Soc. vol xxvi. (1870) p. 486.
Fig. 11. — Specimen of Triarthrus
Beckii, shmviw/ the antenna;.
(After Beecher.)
Digitized byJSoogle
426 MB. H. M. BERNARD OK THE [Aug. 1 894,
to Apus lit* in Ou fact that in 0*i* form we have the *]>ecialization of
the mouth-parts which remained typical of the later Crustacea. In
Aptu the second antennae degenerated, that is, as compared with the
anterior pair, their ventral masticatory portions almost, if not
entirely, disappearing. In the third pair of limbs it is the dorsal
portion which entirely disappears, while the ventral develops iuto a
large fleshy jaw. In the last two limbs the dorsal portions persist
in a rudimentary condition, while the ventral are masticatory ridges,
second in importance only to the * mandibles.' On the trunk the
masticatory portion of the limbs progressively gives up its function,
while the dorsal portions develop primarily as organs of locomotion.
There is no reason to believe that any trilobites possessed this
formula for the cephalic appendages. Certainly in the older trilo-
bites, in which we find the head-region either incomplete as to the
number of the segments, or with the typical number of segments but
not very closely fused together, it was not likely that the limbs of
these segments were specialized like those of Apus and the higher
Crustacea, in which the head-segments are fused beyond all further
recognition as such. Judging, indeed, from those merostomata
whose cephalic limbs we know anything about, there is reason to
believe that the trilobites tried almost every possible masticatory
formula.
1
As to the limbs of the trunk, Burmeister assumed that they were
membranous ' lobes ' like those of Apus and Branchipus. Recent
discoveries, however, show that the ambulatory portion of the leg
was filiform ; yet Burmeister was not far from the truth. The limb
of the trilobite, according to Walcott's sections, was a bi ramose
appendage, with a gill, a cirrus (exopodite), and a locomotor}' ' endo-
podite,' and, what is of equal, if not of greater importance, a flat,
membranous, basal portion.
Commencing with the distal portion of the leg, Walcott's claim
that it was biramose has now been fully confirmed by the discovery
of specimens of Triarthrus Beckii
showing appendages.1 In those Fig. 12. — Limb of Triarthrus
beautiful specimens we have the Beckii. (After Btecher.)
distal portions of the limbs shown
us closely resembling those of
Apus, only in Apus the two
branches are flat and mem-
branous for swimming, while in
Triarthrus they are apparently
longer and narrower and second-
arily jointed, for crawling. As
all who have examined Apus
know, the two branches are arranged side by side exactly as we find
in Triarthrus (fig. 12), the exopodite being behind the endopodite.
' See Wulcott'a valuable paper quoted abo»e, and also the more recent paper by
Matthew, nnd further Dr. C. E. Beech er, 4 On the Thoracic Leg* of Triarthrus,'
Auier. Juurn. Sci. ser.3, tol. xlvi. (18U3) p. 407.
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION OF THE TKILODITK8.
427
It is only when the limb is flattened out under a cover-glass that
the exopodite assumes its true morphological position as a dorsal
appendage of the endopodite, branching off laterally in the transverse
plane. Further, the Hat rowing exopodite of Apus is supplied with
a fringe of sensory hairs. These hairs are very marked on the
exopodite of Triarthrus, which, a3 above noted, has the same position
with reference to the endopodite as in Ajnis.
Proximally to these two branches, Ajtus has a gill on the dorsal
side of the limb. This organ is either not uncovered in any of the
described specimens of Triarthrus, or else was quite rudimentary
in these animals. But Walcott's researches have led him to the
conclusion that the trilobites possessed gills in the typical place,
and often, in adaptation no doubt to their manner of life, highly
specialized structures.
Fig. 13. — Section o/Calymene Fig. 14. — Corresponding section
senaria. {After Walcott.) through Apus (Lepidurus)
spitzbergensis, Bernard.
So far, then, we have the limbs of the trilobites fundamentally
of the same type as those of Apus. But the question of prime
importance still remains to be answered — were the trilobite-legs
phyilopodan, or, considering their more filamentous distal portions,
do they show any traces of having been originally membranous
appendages with broad transverse insertions ?
Walcott's figures appear to me to leave no doubt on this point.
The sections (figs. 13 & 15, from Walcott) are almost exactly
paralleled by longitudinal sections of Ajms (figs. 14 & 16), so far,
that is, as the section through the limbs is concerned. Tho limb of
Apus has a long transverse attachment, partly to the ventral and
partly to the lateral surface of the body. Sagittal sections cut
laterally (fig. 16, p. 428) show the divisions between the limbs running
high up* the sides of the body as in the corresponding section of
Calymens senaria (fig. 15, p. 428). Fig. 13 shows a section through
the same trilobite, and fig. 14 one through Apus, passing through the
lobate basal portion of the limbs farther in, that is, nearer to the
median plane. On compariug the four sections here given, we thus
have, in both animals, the attachments of the limbs occurring not
only in tangential sections, but in those taken much farther iu
towards the median line. This can have but one explanation, namely,
Digitized by Google
428
MR. H. M. BERNARD ON THE
[Aug. 1894,
that the limbs in Calymene, as in Apus, had long transverse lines of
attachment. Further, the shape of the limbs of A pus in section
is almost exactly the same as the sections of the limbs shown in
Calymene senaria. This comparison with the section of Apus makes
it very clear that the section (fig. 13) passed through the mem-
branous basal portions of the limbs of Calymene, and does not contain
longitudinal sections of the legs themselves, showing traces of joints,
as Walcott very naturally, but I think erroneously, infers.
Fig. 15. — A more tangential Fig. 16. — Corresponding section of
longitudinal section of Apus (Lepidurus) spitzbergensis,
Cnlvmene senaria. {After Bernard.
Walcott.) ^
That the limbs in the trilobites had long transverse insertions, as in
Apus, seems to me also to be established by fig. 17 (from Walcott),
which represents a rolled-up Calymene senaria with a portion of the
dorsal test broken out, showing a cast of the ventral surface. From
this we see that the limbs were certainly, at their origin at least, mem-
branous lobes which sloped forward, as shown in fig. K5(p. 427). Wal-
cott himself does not seem to have allowed for this forward slope, in
concluding from his sections that
the membranous lobe had but Y\g. 17. — Enrolled Calymene.
comparatively a short transverse (After Walcott.)
attachment, the limb afterwards
swelling out transversely into a
flat triangular basal piece. If
the plane of transverse section
passed through the apex of one
of the bent 1 black lines repre-
senting the lines of insertion
of the limbs in fig. 17, we
should get exactly the appearance
adopted by Walcott in his ideal [The dorsal test is broken, showing a
restored section, t. e. a broad cast °f inner ventral surface. J
basal joint with narrow attach-
ment. Further, Walcott's own sections show in other places that
the line of insertion was in reality not so short.
Judging, then, from these valuable sections compared with trans-
1 I cannot be quite sure whether I am interpreting the figure correctly ; part
of the lighter lines may be meant to represent dorsal muscular apophyses. This,
however, would not affect the main argumeut.
Digitized by Google
Vol. 50.J
SYSTEMATIC POSITION OF THE TItlLOJUTKS.
429
verse and longitudinal sections of Apus, I am convinced that the
basal regions of the limbs of trilobites were membranous lobes with
long transverse insertions, which probably passed laterally into the
membranous under-surfaces of the pleura. Fig. 15 is, I think,
completely explained by this supposition.
These membranous basal plates probably projected inwards
towards the ventral median line all along the trunk, as they still do
in Apus, perhaps as segmental repetitions of the masticatory plates
round the mouth. In Apus, I believe, they are still functional,
and servo to push food forward towards the head and mouth. The
anterior pairs are armed with teeth, and foreshadow the maxilli-
pedes of the higher malacostraca.
We conclude, then, that the limbs of the trilobites, in spite of
their development of filiform ambulatory legs, were originally mem-
branous lobes, and that their basal regions persisted as such. This
is of primary importance, as it places their affinity with the phyl-
lopods beyond question.1
Of equal importance is tho fact which I have elsewhere already
insisted upon, that the limbs of the trilobites show the same
gradual diminution in size from front to back which we find in
Apus, the most posterior being quite minute and rudimentary. Tf
my explanation of this remarkable phenomenon be correct, namely :
that these posterior segments are fixed in an undeveloped larval
condition, then these early phyllopods were clearly not very far
removed from ancestors with a very much richer segmentation than
they themselves possess, or than Apus possesses. Apus cancrifonnis
develoj>s, or commences to develop, upwards of sixty segments, and
may thus well be descended from a form with seventy to eighty,
or even a hundred segments.
Summary.
It is now possible, from the foregoing considerations, to fix with
gTeat probability the zoological position of the trilobites. The
bending round ventrally of the first segment, the great labrum with
antennae attached at its sides, the * wandering ' of the eyes, the pores
(pointing to the probable presence of water-sacs), the head with a
varying and progressively increasing number of segments, the dorsal
organ, tho rudimentary character of the posterior segments, and the
gradual diminution in size, with the essentially lobate or phyllopodan
type, of the limbs, all serve to connect the trilobites with Apus,
This relationship cannot, however, be considered as direct. Apus,
on account of its richer segmentation, the absence of pleurae on the
1 [Since this paper was read. Dr. Beecber has deecribed the 4 Appendages of
the Pygidium of Triarthrus? Araer. Journ. 8ci. ser. 3, vol. xlrii. p. 298, April,
1894. The limbs of the rudimentary pygidial segments of Triarthrus are almost
indistinguishable from the rudimentary limbs of the larval segments in a growing
Apus, which till now were unique among the limbs of arthropods. The limbs of
trilobites, whatever their adult form, were therefore beyond question develop-
ments of originally nbyllopodan appendages. Their transition* from front to
back, that is, from filamentous to membranous, is also exactly paralleled in
Apus, tee figs. 9, 4, 5, and 10 in 'The Apodidse.' — H. M. B., June, 1894.]
a J. G. S. No. 199. 2 o
Digitized by Google
430
MR. II. M. BERNARD ON THE
[Aug. 1894,
trunk-segments, and its more membranous parapodia-like limbs,
must be assumed to lie in the direct line upwards from the original
annelidan ancestor towards the modern Crustacea. The trilobites
then must have branched off laterally from this lino either once or
more than once, in times anterior to the primitive Apus, as forms
specialized for creeping under the protection of a hard imbricated
carapace. This carapace was obtained by the repetition, on the
trunk-segments, of the head-shield which, as we have already seen,
almost certainly existed as a structure sui generis in earlier forms,
and, somewhat modified, has been retained as such in the early
Crustacea proper (' Aspidophora').
Reading downwards, we should arrange the relationship aa
follows : —
A richly segmented annelidan ancestor, with the first segment bent round,
so that the labrum and mouth point backwards, in order that the parapodia
may function as mouth-parts ; projections due to this bending round occur at
the side* of the first, or flexed, segment.
The second segment fuses with the first to form a head of two segment*.
The lateral projections, secondarily specialized, are repeated on the second
segment as pleurae, which fuse with the lateral projections of the first segment.
Three segments form the head-region, and two pairs of pleura) fuse with
the lateral projections to form a head-shield.
Four segments form the head- ^ Microdiscus and other trilobites
region, and their lateral projections
form the head-shield. This head-
shield is not repeated as pleurae along
the trunk-segments.
1
Five segment* form the head-
region, their pleurae forming the
head-shield, which w not repeated as
pleura: along the trunk-segments.
Head-shield developing backwards
as a earapaoe. Apus.
Modern Crustacea.
which have only four segments in
the head, and in which tho head-
shield is repeated as pleurae along
the trunk-segments. *
i
OUndlus and other trilobites with
five head-segments. These may either
be deduced from trilobites with four
head -segments, or have branched off
independently from the main stem.
The pleurae are repeated along the
trunk-segments for a creeping manner
of life. With various formula;
of the cephalic limbs.
1
Trilobites (e. g. Ogygia) with six
segments forming the cephalic region,
due probably to the association of
the powerful limbs 1 of the sixth
segment with the mouth-
Limulus.
-parts.
Eurypterids (with
secondary degenera-
tion of the pleurae).
1 Compare the special development of the first trunk-limbs of Apus, and of
Calymene according to Walcott's restoration.
Digitized by Google
Vol. 50.] SYSTEMATIC POSITION OP THE TRILOBITBS. 431
In this provisional classification we have assumed that Micro-
discus and Olendlus branched off, perhaps independently, from the
main stem, as forms specialized for creeping — by the development of
the pleurae along the whole length of the body. It is obvious, of
course, that there is an alternative scheme, namely, that which assumes
that Microdiscus and OUnellus stand more or less in the direct line,
and that Apus branched off from Olerullus (each having five head-
segments). Apus in this case would be a later specialization, charac-
terized by a failure to devolop the pleurae (for example, the Eury-
pterids) along the trunk-segments, perhaps in adaptation to a more
free-swimming manner of life. In that case, its cylindrical vermi-
form body would be a return to ancestral conditions.
The classification would then be as follows : —
Browsing annelid, with first segment bent round, and lateral projections.
With two segment* fused to form the head, the lateral projections being
repeated all along the body as pleura;.
With head of three segments, etc. The same.
With head of four segments, e. g. Microdiacta and others.
With head of five segments, e. g. Olentlliu and other trilobites with
five head-segments.
Trilobites with six cephalic segments. Aptts, in which the pleura; are
secondarily limited to the head-
t jr segments, forming the bead -shield,
Eurypterids(also Limulus. which by backward prolongation
with secondary de- becomes the carapace,
generation of the
pleurae).
For my own part, I find the former classification the more
acceptable. The repetition of the head-shield as pleurae along the
trunk-segments, seems to be the specialization which characterizes
the trilobites. If Apus cannot show the primitive segmentation of
the head, no trilobite can show the vermiform body and the rich
segmentation of Apus.
It seems to mo, therefore, that the trilobites, studied in the light
of new discoveries, especially of thoso which we owe to American
investigators, yield the most interesting and important evidence as
to the origin of the Crustacea. Stripped of their pleurae and of the
expansion of the head-shield, we have, in the early trilobites (e. g.
OUnellus), long segmented animals tapering at the posterior end. The
first segment is bent round ventrally,so that tho large labrum points
backwards. The appendages of the first segment appear to have
functioned as sensory organs and to have pointed downwards, being
inserted at the sides of the labrum. The following segments were
provided with membranous lobate appendages carrying, on their
2o2
Digitized by Google
432
Mli. H. M. BERNARD OX TOE
[Aug. 1894,
dorsal edges, gills and sensory cirri, and distally specialized into
locomotor^ organs. The alimentary canal ran through the whole
length of the body, bending round anteriorly to open through the
mouth.
The trilobites may thus be briefly described as fixed specialized
tinges in the evolution of tfie Crustacea from an annelidan ancestor,
which bent its mouth round ventrally so as to use its parapodia as
jaws.
Postscript on the Relation of the Isopods to tJu Trilobites.
[The suggestion that the isopods are the modem representatives
of the trilobites must be judged on its own merits. The argument
in the foregoing paper is not in any way affected by it. The
relationship between Apus and the trilobites would remain intact,
the question being merely the following, "Can the isopods be
deduced directly from trilobites with five head-segments, that is, can
they be drawn from the main crustacean stem below Apus, or have
they branched off from the higher Crustacea above Apus9. " The
former is practically the position taken up by MacLeay 1 (referred to
by the President in the discussion which followed the reading of
the above paper). That able observer recognized the relationship
between Apus and the trilobites, but placed the latter between
Apus and the am phi pods, probably without any clear notion of
what we now mean by descent.
I am myself disposed to think that the isopods and amphipods
are but repetitions of the same process above Apus as that which is
illustrated by the trilobites below Apus. If the trilobites were
primitive Crustacea lower than Apus, specially adapted to a
creeping mode of life, the isopods may be crustaceans higher
than Apus adapted to the same mode of life, and therefore closely
resembling the trilobites. The well-developed anteriorly-placed
antennae, the unmistakably crustacean mouth-formula, the sharp
division into thorax and abdomen, show the isopods to be Crustacea
above Apus. Hence I cannot help thinking that they are related
to the trilobites, not directly, but indirectly through Apus. — June,
1894.]
Discussion.
The President complimented the Author on the clear manner in
which he had shown the homologies between the ancestral form
Apus and the trilobita. He called attention to W. S. MacLeay *a
' Observations on Trilobites/ published in 1839, in which MacLeay
had proposed to place the trilobita between the entomostraca and
ziphosura on tho one hand and the isopoda and amphipoda on the
other. He thought that MacLeay deserved credit for his acute insight
into the relations of these forms, and that, too, at a time when but
1 W. S. MncLefly, 4 Observations on Trilobites, founded on a Comparison of
their Structure with that of living Crustacea,' in Murclnaon's 'Silurian
Syetem,' pt, ii. 1839, pp. 666-669.
Digitized by Google
Vol. 50.]
SYSTEMATIC POSITION OF THE TKILOMTK3.
433
little advance had as yet been made in the study of the arthropoda.
While he agreed with Mr. Bernard that the earlier trilobites presented
forms with very numerous segments, he pointed out that the later
ones showed signs of advance — in having fewer free thoracic rings and
a well-developed pygidial shield. He had always cherished the idea
that the isopoda might have branched off at some distant time from
the trilobita, and he drew attention to such points of structure as
the pores in the free cheeks, which were present in such isopods
as Sphceroma and Serolis, and in such trilobites as Phillipeia,
OriffUhides, Ampyx, and Trinucleus. The way in which the neck-
segment is folded around the glabella and forms the free cheeks in
both isopods and trilobites must also be deemed significant.
The discovery of such well-preserved limbs, by Dr. Beecher, in
Triarthrus Beckii justified the Author in regarding at least these
earlier trilobites as extremely entomostracan in character.
The Rev. T. R. Stbbbixo agreed with tho Author in thinking
that the trilobites have little connexion with the isopods, though
the resemblance is sometimes striking, and is often favoured rather
than otherwise by the character and position of the eyes. But,
whereas the isopods are distinctly malacostracan, with a number of
segments never exceeding twenty-one, the number of segments in
a trilobite varies as readily as the fashion of a lady's dress. More-
over, in many isopods the mandibles are stout and tho limbs either
strong or long and prominent, making it improbable that the body
of the animal should be fossilized without leaving any trace of the
appendages, as appears to have happened with the majority of the
trilobites. On the other hand, Apus and Lepidurus seem to have
still less claim to any close alliance with the trilobites, the two
groups being quite devoid of any general resemblance, the phyllo-
pod8 in question having a large carapace extending back over the
segments of the thorax, on which the head-shield of the trilobite
never encroaches. The tail or pleon of the trilobite is, as a rule,
transverse and compact, that of the phyllopod elongate and flexible.
Of the phyllopod limbs many are lamellar, while in Walcott's resto-
ration of the trilobite Calymene senaria there is a continuous series
of legs, all slenderly articulated. If mere guesses are allowable,
the suggestion may be hazarded that of living animals the group
nearest the trilobites may be the myriapods, as these have a long
series of slenderly articulated legs, and segments both numerous and
variable in number. The still prevailing obscurity of tho subject is
illustrated by the fact that Walcott compares certain appearances
in his sections of Silurian trilobites with the spiral branchiae of a
whale-louse, a parasitic amphipod of probably quite modern deve-
lopment. In the figure of a specimen of Triarthrus Beckii, a pair
of antennae are represented projecting straight forward from the
centre of the head-shield. It may well bo wondered where the
points of attachment of antennae so placed are to be found on the
underside of the trilobite's head.
Prof. G. B. Howes said that he believed the discover)' of the
terminal anus in the trilobite dealt the death-blow to the association
Digitized by Google
434
THE SYSTEMATIC POSITION OF THE TKILOBITE8. [Aug. 1894,
of the trilobites with the arachnoid series. He advanced reasons for
accepting the Author's homology of the median cephalic pore of the
trilobites with the aperture of the dorsal gland of Apus^ and for
believing that in the latter we are dealing with an organ early
differentiated in the crustacean series, but now for the most part
lost — the 4 dorsal organ ' of embryologists being its vestigial homo-
logue. He believed that the facts and arguments brought forward
by the Author of the paper proved the trilobites to be Crustacea,
and fully justified their association with Apus as an early offshoot
on the crustacean line. He considered that in demonstrating the
progressive fusion of head-segments among the trilobita the Author
had shown those animals to have so far undergone a parallelism of
modification to all other great groups of arthropods. If, as he
believed, the degree of this fusion was the surest guide to the
position of any one member in an arthropod series, that being the
higher in proportion as the fusion is numerically the greater, the
places customarily assigned to the Scorpionidae and the Araueidae by
the advocates of the ZimuZw*-an-arachnid theory must be trans-
posed— the scorpions becoming the culminating members of the
arachnoid series. Judged from this standpoint, the superficial re-
semblances between Limulus and Scorpio appeared to him closely
akin to those between, say, the flying squirrels and OaUopithecuSy
or between the JRana jerboa and Bufo jerboa of Borneo, and sug-
gestive of isomorphism by convergent modification. To definitely
assert that Limulus is an arachnid appeared to him on a par with
saying that the * flying lemur ' is a squirrel, and the Bufo jerboa a
frog.
Mr. Malcolm Laurie also spoke.
The Author, in reply, said that none of the objections dealt with
points of any morphological importance The head-shield in Apu*
developed by backward prolongation into a carapace, and in the
trilobites gave rise to the pleurae by segmental repetition, as any
prominent cuticular structure might be repeated. It was enough
that the antennae in both were inserted at the sides of the labrum,
and that the trunk -limbs were of the same type, with 4 endopodite,'
* exopodite,' and gills, and, what was still more important, with
broad lines of insertion. That the trilobites might be myriapods
could not have been seriously suggested. The subject was neces-
sarily speculative, and the value of a speculation depended upon the
evidence in its favour ; in the present case, all the available evidence
tended to establish tho affinities proposed.
Digitized by Google
VoL 50.]
NAIADIfKS FROM NOVA SCuTIA.
4*5
27. Note on the Omus Naiadites, as occurring in the Coal Forma-
tion of Nova Scotia. By Sir J. William Dawson, C.M.G.,
LL.D., F.R.S., F.G.S. With an Appendix by Wheeltos
Hind, M.D., B.S., F.lt.C.S., F.G.S. (Read February 21st,
1S94.)
[Plate XX.]
In the autumn of 1892 Dr. Wheclton Hind was so kind as to invite
me to place in his hands, for study and comparison, specimens of the
bivalve shells from the Coal Formation of Nova Scotia, which I had
described undor the above generic name, 1 and some of which were
described by the late Mr. Salter in the Quarterly Journal of this
Society, vol. xix. (lbG3), under his new generic names Anthracoptera
and Anthracomya. Owing to illness I was unable, at the time, to
comply with Dr. Hind's request, and thus the Nova Scotian species
• lost the benefit of a detailed comparison with the British forms in
Dr. Hind's excellent paper of May 189Ji.v I have now sent a col-
lection of specimens to him, and beg to make the following remarks
thereon.
These shells occur plentifully in some of the argillaceous shales
of the Coal Formation, and occasionally on the surfaces of flaggy
sandstones, but the most abundant repositories are the beds which
I have named 4 calcareo-bituminous shales' aud 'bituminous lime-
stones,' beds which, on account of their superior toughness and
black colour, often stand out prominently in the coast-sections, and
are sometimes almost entirely composed of these shells.11 As none
of the properly marine species of tho Carboniferous Limestone ever
occur in these beds, and as they are closely associated with the coal-
seams, I have always been greatly interested in them — in connexion
with the various theories of the deposition of coal. 1 referred to
them in this relation in 4 Acadian Geology,' 2nd ed. 1S0S,4 in the
following terms : —
44 All tho lamollibranchiatc shells, which are so numerous in some
of the shales and bituminous limestones of the Joggins that some
of the beds may bo regarded as composed of them, belong to one
generic or family group. They are the so-called Modiolas, Uuios,
or Anodons of authors. I proposed for them, some years ago,
the generic name of NaiadittSy* and described six Bpecies from
the Coal Measures of Nova Scotia, stating my belief that they are
allied to Unionidtc, and that their nearest analogue may be the
genus Bi/830-anochnta of D'Orbigny, found in the river Parani.
1 « Acadian Geology,' Suppl. 1st ed., 18G0.
3 Quart. Journ. Geol. Soc. vol. xlix. p. 249.
* See section of tho South Joggins, in 'Acadian Geology,' 2nd und later
editions.
« Pp. 202, 203.
* ' Acadian Geology,' SuppL 1st ed.
Digitized by Google
43«
81K J. W. DAWSON ON XAIADITES IN
[Aug. 1894,
Mr. Salter, however, to whom I sent specimens, regards these shells
as belonging to his new genera Anthracomya and Anthracojdera, the
former being supposed to be allied to Myadae.1 More recently
Gumbel and Geinita have described similar shells from Thuringia
as belonging to the genera Unto and Anodon, and regard my Naia-
diies carbonarius (Anthracopttra carbonarui of Salter) as a DreUscna*
In the present uncertainty as to their genuine relations 1 shall retain
the name Naiaditcs for the whole of the species, giving, however,
Salter s generic names in brackets."
In correspondence with Mr. Salter at that time, I had pointed out
that these shells were probably freshwater, and objected to his
name Anthracomya as expressing an incorrect view of the affinities
of the shells that I had sent to him ; assigning the following among
other reasons, afterwards published in 1868 in a new edition of
4 Acadian Geology ' along with descriptions and figures of the principal
species, seven in number : —
(1) Under the microscope these shells present an internal lamel-
lar and subnacreous layer, a thin layer of prismatic shell, and an
epidermis, all corresponding to similar structures in the Unionidre.
(2) The ligament was external ; there seem to have been no teeth.
The shell was closed (or slightly open) posteriorly, and in some
species there are indications of a byssal sinus. The general aspect
is in some species that of Unio, in others that of Mytilus. The
wrinkling of the epidermis seems to be, for the most part, an effect
of pressure.
(3) I know of no instance of the occurrence of these shells in
the marine limestones, or associated with species unquestionably
marine.
(4) The mode of their occurrence precludes the idea that they
were burrowers, and favours the supposition that they were attached
by a by8sus to sunken or floating timber.3
(5) The attachment of Spirorbis to the outer surface of many
specimens seems to show that they were free in clear waters.
On these grounds, and being unable from the specimens in my
possession to make out evidence of generic distinctness, I continued
to use the name Naiadites in preference to adopting the newer
names suggested by Mr. Salter. Under this name I have described
seven species from the Coal Formation of Nova Scotia, and have now
sent specimens of these to Dr. Wheelton Hind for examination and
comparison.
I may odd that I do not object to the division of the species into
two or more genera, for one of which Salter's name Anthracoptera
should be retained. I doubt, however, whether these can be distin-
guished by form alone, which in most cases is all that we have
1 Quart. Journ. Geol. Soc. vol. xix. (1863) p. 80.
2 Neues Jahrb. 1864, pp.646, 651, and Geol. Mag. 1865, p. 204.
• Dr. Hind informs me that a specimen in the British Museum (Nat. Hist.),
at South Kensington, has the byssus preserved. [This specimen consists of
a piece of fossil wood, round which numerous individuals of Anthracoptera are
clustered in eeferal rows, as they would be if attached by a byssus. — W. H.]
Digitized by Google
Vol. 50.]
inn COAL-FORMATION OP NOVA SCOTIA.
437
to depend upon. The species seem also to have been very variable,
and they present very different appearances in different states of
compression.
I may also mention that Dr. Wheelton Hind has been led into
an error in supposing that Estheria Bawsoni, described by Prof. T.
Rupert Jones, F.R.S., in the Geol. Mag. for 1870, may be the same
with my Naiadites hrvis. These shells are quite distinct in forms,
markings, and structure, and occur at very different positions in the
Carboniferous. N. Icuvis has been found only in a flattened state :
its epidermis is strong and wrinkled, and the shell shows traces
of prismatic structure.
The associates of Naiadites in the admirably exposed sections of
the Nova Scotian coal-field, at the South Joggins and Sydney, Capo
Breton, are various species of minute bivalve crustaceans, Eury-
pterids, Anihrapalczmon? scales and teeth of ganoid fishes, and
Spirorbis. The beds also hold much carbonaceous matter and
fragments of fossil plants* often with fyrirorbis attached. In some
cases the beds of Naiaditssshale form the roofs of small coal-seams.
In a few they have been elevated into soils and have been pervaded
with Stigmaria-Toota, thus resembling underclays. Their whole
conditions point to land-locked ponds or lagoons, or to sluggish creeks.
From the continuity of the beds these would appear sometimes to
have been extensive, and, in addition to the animals already referred
to, they were visited by ganoid fishes of large size, of tho genus
Rhizodus, and by small sharks of the genus Diplodus (Oracanthvs),
They were also tenanted by the aquatic batrachians of the period.
As the supposition that the shells of Naiadites were marine
has placed them out of relation with their associates in the Coal
Formation of Nova Scotia, it is a source of gratification to me, and
an important contribution to the theory of coal, that their true
affinities have now been so ably illustrated by Dr. Wheelton Hind.
Appendix.
Through the courtesy and kindness of Sir J. William Dawson I have
been favoured with a perusal of his * Note on tho Genus Naiadites*
and have carefully examined at his request a series of shells from the
South Joggins, as well as a scries from the collection of the Geological
Survey of Canada, forwarded to me for that purpose.
From an examination of these specimens it is easy to understand
Sir William's attitude in considering it impossible to discriminate
with any certainty between the different genera of shells in the
South Joggins coal-field. They were all more or less crushed in the
shale, and therefore showed no interiors, and often the proper
external characters were masked. I am quite of the opinion now,
from the knowledge I have obtained by a long familiarity with
nearly perfect forms, that the genus Naiadites contains three distinct
genera, for one of which the name must be retained. These three
genera are the same as those which generally occur in our Coal
1 A. HUliana, Geol. Msg. 1877, p. 56.
Digitized by Google
DE. WHEELTON IITSD OS NAIADITES IN
[Aug. 1894,
Measures, a fact which was recognized by the late Mr. Salter, who,
in a description of Sir William Dawson's shells, Quart. Journ. Geol.
Soc. vol. xix. (1863), substituted the names of his newly-erected
genera Anthracoptera and Anthracomya for Naiadites, notwith-
standing the critical objections raised by the author of the name
Naiadites.
I have been in correspondence with Sir William on the subject,
and propose to retain the name Naiadites for the form called
Anthracoptera.
In my paper published in this Journal, vol.xlix. (1893), p. 249, 1
figured and showed that Salter's Anthracoptera had a striated hinge-
plate, a character, the absence of which had been considered .to
separate the genus Myalina (Do Koninck), and in Geol. Mag. 1893,
p. 514, I published a note on Myalina crassa, pointing out that
there were no anatomical features by which the shells known by
that name could be separated from Salter's Anthracoptera, at the
same time noting that the septa within the beaks described by
J)e Koninck were absent. On looking up Be Koninck's original
description and figures I find in 1842 (4 Descript. dee Animaux
Fossiles,' p. 125) the following description : — " A l'interieur et
immediatement au-dessous de ceux-ci [the umbones], une petite lame
septiforme, semblable a celle que Ton observe dans certaines especes
de Mytilus." The figure given is too imperfect to show these
characters. In his more recent work, * Faune du Calcaire Carboni-
fere,' 1 he describes the genus and says it is *« muni d'une cloison
interieure," but the figures, especially figs. 5, 7 and 9, pi. xxix.,
demonstrate most conclusively that this septum did not exist in
them.
Prof. King (l Permian Fossils,' pi. xiv. figs. 5, 7 & 12) shows
shells from the Permian which appear to possess this myophorial
septum, to which he gave the names Mytilus squamosa* and M.
septifer, but in the text he suggests their reference to De Koninck's
genus.
M'Coy (' Brit. Palaeozoic Foss.' p. 492) says, in his description of
Myalina, that there is "a triangular septum in the cavity of each
beak, parallel with the plane of the lateral margins, leaving deep slits
under the beaks of the cast," but he mentions no specimens from
the Carboniferous series. When in the Brussels Museum a few
months ago I was unable to 6ee any signs of the septa in De
Koninck's specimens, and think it probable that many of his forms
will have to bo placed with Naiadites, the name Myalina being
retained for the septiferous forms from the Permian, and for any
which may appear in the Lower Carboniferous series.
[It has been thought advisable, at the suggestion of the Council
and with the assent of the author, to incorporate here the following
synonymy of Naiadites. — Ed.]
1 Ann. Hist. Nat. Musee roy. de Belgique, vol xi. 1885.
Digitized by Google
Vol. 50.]
TUB COAL-FORMATION OF NOVA SCOTIA.
439
Srwoimrr of Naiadties.
1840. Naidea, Swainson, for f 'n to-like mollusas.
1845. Naidea, Buckman, ' Geology of Cheltenliam,' Rha?tic and Stonesfield
plants.
1845. Naiadita, Brodie, Fossil Plants (in ' Fossil Insects ').
1850. Naiadita, Buckman, adopted in Quart. Journ. Geol. Soc. rol. vi. p. 415.
1853. Dawson figured several Molluscs from Nora Scotia resembling Modiota
and Unto, Quart. Journ. Geol. Soc. vol. x. (1854) p. 39.
1854. Naiadties, Morris, for Naidea aud Naiadita, in his 'Catalogue of British
Fossila.'
1855. Dawson again figured one of these molluscs as a Modiola, 'Acadian
Geology,' 1st ed. p. 148.
1800. Dawson gave a short description of the shells and referred to the above
figure, provisionally naming it Naiadties. lie described also several
species ; the tint and type species boing Naiad ties carbonarius. Sup-
plement to 1st ed. ' Acadian Geology,' p. 43.
1801. Salter gave the name of Anthracotnya to certain British Coal-measure
molluscs with full descriptions and figures, Mem. Geol. Surv., ' Iron
Ores of Great Britain,' pt iii. p. 2211.
18G2. Salter speaks of three species of Naiadties ho had received from Dr.
Dawson, namely Naiadties elonyatus, N. carbonarius, and N Utvis,
The first and last of these he refers to Anthracomya, and for the other,
JV'. carbonarius, Dawson's type, he proposes the nuiuo " Antkracoplera
for these triangular shells."
If the name of Naiadties' can be retained for any of these
molluscs it must be for this type-species N. carbonarius, for which
Salter erroneously proposed the generic name of Anthracoptera, Quart.
Journ. Geol. Soc. vol. xix. (1863) p. 80.
Note. — Wheelton llind, 1893 (see below), says that the form figured
by Salter, Quart. Journ. Geol. Soc. vol. xix. p. 79, fig. 3, as Anthracoptera
carbonaria is not the same as Dawson's type, « Acadian Geology/ 1st
edit. p. 148, and Quart. Journ. Geol. Soc. vol. x. p. 39.
1808 A 1878. Dawson gives figures and descriptions of these Nova Scotian shells
and partially adopts Salter's names as sub-genera for some of the
species, thus: Naiadties (Anthracoptera) carbonaria, Naiaditts (Anthra-
corny a) elonyata, Naiadties (Anthracoptera) lavis; but speaks against
Salter's idea of the marine nature of these shells (as quoted above,
p. 430), 'Acadian Geology,' 2nd A 3rd edit. p. 202 et seoq.
1893. Wheelton Hind adopts Salter's two genera Anthracomya and Anthra-
coptera, for the British species, but says that the specimen from
Uova Scotia figured by Salter aB Anthracoptera carbonaria is not the
tame as Dawson's Naiadties carbonarius ; the latter. Hind says, is
an Anthracomya, Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 249.
1894. Wheelton Hind in the MS. of the present paper proposed to adopt
Naiadties for Anthracomya, and to retain tho name of Anthracoptera
for the type-species of Naiadties. He now acknowledges that Salter's
Anthracoptera carbonaria is the same as Dawson's Naiadties carbo-
narius. The genus Naiadties, therefore, will have to be used and
Anthracoptera discarded. The British forms referred to tho latter
genus, in tho author's 1893 paper, will now be called Naiadties.
I must admit tho error of which I am convicted by Sir William
Dawson— namely, that I confounded Naiaditts lavis and Estfieria
Dawsoni — the more so as the fault was due to carelessness in com-
paring the numbers of quoted pages.
I am not ablo to state that any of the species submitted to me
are the same as British forms, therefore the specific names must
still remain, though, if at any time in the future moro perfect
specimens are obtainable, it may be quite possible to do so.
Digitized by Google
440
DR. WHEELTON HIND ON NAIADITES IS [Aug. 1894,
I have a aeries of specimens from the South Joggins labelled by
Sir J. William Dawson Anthracoptera carbonaria. They existed
in very large numbers in some of the shales of the South Joggins,
so much so that tho greater part of the mass is composed of debris
of this shell, with entomostrara and vegetable remains. I have
little or nothing to add to Sir AVilliam's original specific description,
but would point out that his original figure is very misleading, and
that Naiadites carbonariu*, Dawson, differs much from the figure of
Antiiracoptera carbonaria, Salter (Quart. Journ. Geol. Soc. vol. xix.
1863, p. 79), and it was this difference which led me to suppose
that Dawson's original specimen was probably Anthracomya
(Quart. Journ. Geol. Soc. vol. xlix. 1803, p. 249). The umbones
were not shown to be terminal, and were described as " acute in
the anterior fourth of the shell," while I thought Salter's figure
was that of a specimen of one of his Anthracoptera.
I am bound to say that Salter's figure more nearly represents
the shells which have been sent to me as Naiadites carbonarius. In
shape this form approaches somewhat to that of Naiadites (Anthra-
coptera) modiohris, but tho umbones arc more raised above the
hinge-line, more pointed and not curved anteriorly at the apex.
There is one specimen which reveals a typical interior with
finely striated hinge-plate, bevelled at the exterior of its outer edge,
with trifid anterior muscular scars, and relatively larger posterior-
adductor scar. The posterior end was often sinuated above. The
periostracum shows the typical characteristics of the genus. There
exists, as with us, an elongated form, probably only a variety of
thiB shell ; but it evidently comes from a different bed, the matrix
being a hard, fine-grained, micaceous sandstone (PI. XX. fig. 1). It
would seem to have been less gregarious in its habit, if one may
judge from the paucity of its remains in the specimens to hand.
It is very difficult to be absolutely sure as to the generic position
of the shells figured as Anthracomya elongata, as there are no
specimens showing the hinge-line, ligament, or muscle-scars, but
from the shape they probably belong to this group. There is
nothing to add to the original description, but I think that the sen-
tence describing tho position of the umbones is misleading. It says,
" the beaks obtuse and more anterior," but it is difficult to see what
is the meaning of the word more.1 It cannot refer to the shell
previousl)* described, which is a Naiadites (Anthracoptera) carbo-
narius, and has its umbones very forward ; while, comparatively to
the length of the hinge-lino, the umbones in N. clongalus are sub-
central in the specimen figured.
There appear to have been two forms or varieties of this shell,
one more elongate and comparatively narrower, tho other short and
as broad as long.
With regard to Anthracomya arenacea, the specimen which
Sir J. W. Dawson has sent me is typical of Salter's genus ; it is
allied to the forms found on the Continent, and known as Anodonta
1 [A clerical error for ' W-J. W. D.f May 1894.]
Digitized by Google
Vol. SO.] THE COAL-FOBMATIOX OF NOVA SCOTIA. 441
Ooldfussiana. The original drawing in ' Acadian Geology ' does not
show the gradually expanding posterior end, and would give the idea
that the original was an Anlhracosia. I think the specimen from
the McGill College Collection labelled Naiadile* eloixgatus belongs
to this species. This specimen is nearly 1 inch long, and shows the
typical shape and contour.
Naiadites angulatus (Dawson) I consider to be j ]
a pretty little form of typical shape. In the original drawing the
posterior-superior angle is too much prolonged backward.
Anihracomya ovalis is a somewhat larger, more tumid shell than
NaiadiUs eloiujatus, to which it approaches. I think that the sheila
in a block of Millstone Grit from Riversdale belong to this form ; if
so, it is interesting to note the presence of the same form in the
Upper Coal Measures of the Joggins.
Anihracomya hrvis is very similar to a shell which is obtained,
only crushed flat, from the Wigan coal-field ; the English specimens
are, however, larger.
Prof. Amalizky has fallen into error as to the value of the term
Naiadites, and in his work on the Anthracosidae of the Russian
Permian, 1892, has orccted NaiadiUs into a genus of the new
family Anthracosid®, reserving the term for a set of shells totally
different from the majority of those for which the name was
invented. I have shown above that originally the genus included
Xaiaditcs carbonari us.
„ elongatw. f Carlnmicola 1
Anihracomya arenacea. \ Anthracoxia ) a}UJtuara
ovalis
Anthracomya Ubv{$.
f Carlxmicola
I Bhall take an early opportunity of combating other views on
this subject contained in Prof. AmaUzky's work.
EXPLANATION OF PLATE XX.
Coal-Measure shells from the South Joggins. Tho figures ore of the natural
size, when not otherwise suited.
Pig. 1. Naiadiles, sp. Elongate form. (Unfortunately the artist has inverted
the figure.)
2. Naiadites carbonarius (DawBon).
3. „ „ showing interior. Muscle-pite.
4. Anihracomya arenacea (Dawson).
5. „ „ probably young.
6. „ „ probably young.
7. Anthracomya tlongala (Dawson). x2.
8. M ii »» x2.
9. „ m »• *2.
10. # it ii X2.
1 It is highly probable that the term Anthracosia, King, must give way to
Carbonicola, M'Coy, on the ground of priority, although the lat ter's description
of the hinge-plate is erroneous.
Digitized by Google
442 NALADITES FROM NOVA SCOTIA. [Aug. 1894,
Pig. 11. Slab with (a) Anthracomya clongata.
Anthracomya-, sp/i
(r) A'aiaditr* carbonariiu.
(Collection of the Geol. Survey of Canada.)
12. Anthracomya Utvis (Dawson).
13. Anthracomya rWw (Dnweon). Horizon of the Millstone Grit.
{iSK^W
[Notk. — Specimens 1, 4, 5 belong to Sir J. W. Dawson's collection in the
McGill College, Montreal; specimens 11 & 13 to the Geological Survey of
Canada. The remainder have been presented to me by Sir J. W. Dawson.—
W. H.]
Discussion.
Prof. J. F. Blake observed that tho name NaiadiUs had been
used by Buckman for a Liassic plant in 1845, and therefore was
not available for a Carboniferous shell in 1862. As to the name
Anthracomya, there is no more objection to it on the score of the
shell not belonging to the Myacida? than to the name Ooniomya
for shells belonging to the Anatinida).
Dr. W. T. Blanford said that one important point had appa-
rently escaped Dr. Hind's notice. Mr. Salter, in the Society's
Journal for 1863, retained tho name Anthracomya in preference to
NaiadiUs, because the latter genus had never been described.
Names published without a description have, of course, no claim to
recognition.
Dr. J. W. Gregory pointed out that the use of a generic name in
botany does not bar its subsequent use in zoology ; as the botanists
insist on using names previously used for animals, zoologists have
no option but to do the same.
The President, Prof. T. McKrnny Hughes, and Mr. Marr also
spoke.
Digitized by Google
Digitized by Google
Vol. 50.]
SECTIONS FROM ROMFORD TO UPMINSTER.
443
28. Further Notes on gome Sections on the New Railway from
Romeo rd to Upminster, and on the Relations of the Thames
Valley Beds to the Boulder Clay. By T. V. Holmes, Esq.,
F.G.8. (Read April 25th, 1894.)
On March 9th, 1892, 1 had the honour of reading a short paper
before the Society on the sections seen along the course of this new
railway, dwelling chiefly on the cutting north of Hornchurch,1 in
which a considerable mass of Boulder Clay had appeared, having a
maximum thickness of 15 feet, and a horizontal extension of about
300 yards. The Boulder Clay lay in a slight hollow on the surface
of the London Clay, and was covered by gravel belonging to the
highest terrace of the Thames Valley system in the district, the
surface of which varies from 90 to 120 feet above Ordnance datum.
At that time, and during many months afterwards, but little
work was done in the cuttings nearer Romford than that just
mentioned. The cutting at Butts Green and the more northerly
excavation between Great Gardens and the junction with the Great
Eastern Main Line at Romford remained in an almost stationary state.
During the period between the spring of 1892 and that of 1893 I
visited theso cuttings many times, though without detecting anything
but London Clay and gravel : more London Clay being visible at
Butts Green than nearer Romford. However, last year the Romford
cutting was considerably widened and deepened, and afforded
sections of much greater interest than I had anticipated.
The new railway joins the main line about \ mile north-east of
Romford station. The main line ranges in a north-easterly and
south-westerly direction, that of the new railway is from south-east
to north-west. Sixty or seventy yards south of the main line, the
new railway passes under the Victoria Road, which is parallel with
the G.E.R., thence to Romford station. At another point about 600
yards to the south-east the new line passes beneath the Brentwood
Road. The two roads just mentioned meet together at a point a
few yards south of Heath House, near Squirrel's Heath. The Rom-
ford cutting extends from the junction to a point south of Great
Gardens, but is of especial interest only in the space between the
two roads just mentioned.
On April 25th, 1893, T noticed that the navvies who were at
work 40 or 50 yards south of the Victoria Road bridge were throw-
ing up into tho waggons some dark material apparently less stiff and
more loamy than London Clay. On Saturday, April 29th, I found
the cutting free from workmen and waggons, and a clear vertical
section exposed on its eastern side, from the bridge southward, for
a distance of about 90 yards. Close to the bridge was London Clay,
8 or 9 foet thick, covered by a nearly equal thickness of gravel ; but
1 * The New Railway from Grays Thurrock to Romford : Sections between
Upminster and Romford,' Quart. Journ. Geol. Soc. rol. xlviii. (1892) p. 305.
Digitized by Google
Digitized by Google
Vol. 50.]
SECTIONS FROM ROMFORD TO UPMI5STER.
445
Si
lif
s
o
8
r
3
TO
?
9
g
s
i
fitf* if
it
y;\l
■
4
S
5.
about 35 yards from the bridge the London Clay began to disappear,
its place being gradually occupied more and more by dark silt with
interbedded sand and small pebbles,
and the Thames Valley gravel still
forming tho surface. At a distance
of 60 yards from the bridge this silt
and sand occupied the whole of the
space betweon the surface-gravel and
the bottom of the cutting. And at
85 yards the gravel, which had been
gradually encroaching upon the silt,
came down to the bottom of the
cutting, which was not so deep by
about 3 feet as at the bridge, and
gravel only could be seen southward
of that point.
The section was so clear that the
northern boundary of this silty
deposit was perfectly distinct, though
its former extension southward could
not be ascertained owing to the
erosion which had taken place during
the deposition of the overlying gravel.
It appeared to me to be a fragment
of the silted-up channel of an ancient
stream-course. This old stream-
course must have been of consider-
able size, as more than 80 yards from
the bridge the inclination of the beds
was still southerly, as though the
centre of the channel had not been
reached. On the opposite side of the
cutting material of the same silty
character could be abundantly seen,
but the section had been obscured
by having been sloped. All, there-
fore, that can be said as to the direc-
tion of the channel is that apparently
it was about east and west. Among
the small pebbles visible here and
there were many of Chalk, and it
seemed to me that the contents of
this old silted-up channel had been
very largely derived from the Boulder
Clay. But no fossils could be seen
to indicate fluvial, estuarine, or any
other conditions.
I next visited this cutting on
May 11th, 1893, in the company of
Messrs. W. Whitaker and H. W. Mo nekton, whom I had asked to
visit liomford in order to see the silted-up channel just described.
Q. J.G.S. No. 199. 2h
4
2
r
to
Digitized by Google
446
MR. T. V. HOLMES — SECTIONS ON THE NEW [Aug. 1 894,
But since April 29th the cutting had been widened and sloped, and
though plenty of material such as I have mentioned could be seen,
' the boundaries of the channel, and its relations to the London Clay
and the gravel, had been utterly obscured. However, there seemed
to be traces of Boulder Clay near the channel, and, on walking
southward, we discovered on the western side of the cutting, at a
distance of rather more than 100 yards north of the Brentwood
Road, a considerable mass of Boulder Clay traceable horizontally
for more than 30 feet in the sloped side. It was in every respect
average Boulder Clay, like that seen at Hornchurch, and in it we
found a piece of Kimeridge Clay containing Luci-na minuscula.
Similar fragments were seen in the Hornchurch cutting. This
Boulder Clay was on precisely the same level as that at Hornchurch,
and was similarly covered by gravel belonging to the Thames Valley
system. It was nearly 1£ mile north-west of the Hornchurch
Boulder Clay.
The relations between the Boulder Clay and the silted-up channel
could not be ascertained, as the cutting had been sloped, and
tbey appeared in different parts of it and not in contact. But
Mr. Whitaker was disposed to think that the silty material was
probably of Glacial age.
The finding of the Boulder Clay at Hornchurch left the nature of
the hollow in which it had been deposited an entirely open question.
The additional Boulder Clay of the Romford cutting at precisely
the same level, and also covered by gravel of the highest, and pre-
sumably oldest terrace of the Thames Valley system, tends to show
that both were deposited in a broad valley belonging to some
drainage-system more ancient than that of the present Thames. It
appears to mo that considerable light may be thrown on the probable
course of this ancient drainage-system by a brief investigation into
the distribution of the Boulder Clay towards its southern limits, and
by the leading features in the physical geography of the district.
North and north-west of Romford a tract of high ground, rising
in places to a height of more than 300 feet above Ord. dat., lies
between that town and the valley of the Roding. Towards the north-
east, from Warley through Billerieay and Banbury, and in Tiptree
Heath, north of the Blackwater, we have also an elevated district.
However, along a line nearly parallel with that from Warley to Dan-
bury, but from 3 to 4 miles southward, we find a belt of low-lying
country, mostly less than 100 feet in height, and much of it below
50 feet. South of this lowland tract there is more high ground at
Laindon Hills, Hadleigh, Rayleigh, and Althorne, with a general
trend nearly parallel with those of the areas of high and low ground
just mentioned, though the Thames has now caused a breach of
continuity between Laindon Hills and Hadleigh, and tho Crouch
has made a similar breach between Rayleigh and Althorne.
On comparing maps showing the geology with others illustrating
the physical geography of the district, we find that the Boulder Clay
comes as far south as tho edge of the high ground between Warley
Digitized by Google
Vol. 50.]
RAILWAY FROM ROMFORD TO UPMINSTKK.
447
and Danbury which overlooks the valley between those places and
Laindon, Hadleigh, and Rayleigh. North and north-west of Rom-
ford, around Havering-atte-Bower and Chigwell Row, there is little,
if any Boulder Clay at a level lower than 200 feet above the sea,
except at Maylands, on the western flank of the valley of the Ingre-
bourne. In a broad and general way it may be stated that the
height at which the Boulder Clay exists diminishes as we travel
from the west eastward. Thus, towards the southern edge of the
high ground between Warley and Danbury, it may bo seen here and
there below the 200-foot contour line at heights from about 170 feot
upwards ; and no Boulder Clay whatever is visible on the top of
the ridge of Tiptree Heath, though it appears in the low ground
north-west of the ridge.
Turning to tho river-valleys, we may note that though the
Boulder Clay keeps, as I have said, to ground of 200 feet and up-
wards at Havering-atte-Bower and Chigwell Row, yet it may be
seen 40 or 50 feet lower in the valley of the Roding, to the north-
west, and in that of tho Ingrobourne at Maylands. Eastward,
around Chelmsford, it appears at various levels between 100 and
200 feet, also about Hatfield Peverel and Witham. And in the
river-valleys between Chelmsford and Maldon it descends here and
there even below the 100-foot contour-line.
Thus in the existence of Boulder Clay in the valleys of the Roding
and of the Ingrebourne near Romford, and in those of the Black-
water and its tributary streams around Chelmsford and Maldon, we
have evidence of their excavation, to some extent, before tho depo-
sition of tho Boulder Clay. And as the height at which Boulder
Clay appears in those valleys decreases eastward, we have reason to
believe that the drainage of this district took, as it now does, an
easterly course at the time of the deposition of the Boulder Clay.
Assuming then, as seems most probable, that in the silted-up
channel at Romford we have that of an ancient river, it is obvious,
iu tho first place, that it must have belonged to an earlier system
than that of the present Thames Valley, as it is manifestly older
than the oldest Thames Valley gravel ; secondly, that the Roding
and Ingrebourne must have been among its tributaries, as is shown
by the lowor level of the Boulder Clay south of Romford than in the
valleys of those streams ; and, thirdly, that this Romford river flowed
in an easterly direction. We have now to consider its probable
course eastward.
I think there can be little doubt that, granting the above hypo-
thesis, the course taken by the ancient stream disclosed in the Rom-
ford cutting was through the broad tract of low ground between the
heights of Warley, Billericay, and Danbury on the north, and those
of Laindon, Hadleigh, Rayleigh, and Althorne on the south.
Crossing the present valley of the Crouch, it entered that of tho
Blackwater about midway between Woodham Ferris (or Ferrers)
and Althorno (where the water-parting between the basins of tho
two streams is now only a little more than 50 feot above the sea),
and joined the Blackwater somewhore east of Maldon.
2h2
Digitized by Google
448
MR. T. V. HOLMES — SECTIONS ON THE NEW [Aug. 1 894,
The denudation which has separated this once broad, simple valley
into three parts, drained respectively by the Mardyke, the Crouch,
and the Blackwater, is of very much more recent date. Let us take
the case of the Mardyke. At North and South Ockendon, west of
Bulphan Fen, there is a broad expanse of Thames Valley gravel,
the eastern boundary of which is close to those villages. This
gravel must at one time have ended against higher ground, a little
eastward of its present limits. But it now forms a plateau, the
highest point of which is 110 feet at North Ockendon, and 79 feet at
South Ockendon, while eastward we see a tract of ground about 3
miles in breadth which seldom attains a height of 30 feet. A similar
examination would show that the separation of the valley of the
Crouch from those of the Mardyke and the Blackwater was of
equally recent date.
At length, on my hypothesis, the Thames, locally eating its way
northward, eroded away the high ground intervening between itself
and the Romford stream, and thus tapped the latter's water-supply
and altered the course of the drainage. Fortunately a fragment of
the silted-up and superseded stream-course was preserved. The
course taken by the Thames in its most ancient days, east of Horn-
church, is clearly indicated on the Geological Survey map, in the
deposits of gravel and loam shown at North and South Ockendon,
Chadwell, Mucking, and Corringham. And I think there can be
little doubt as to the correctness of Mr. Whitaker's view that in the
patches of gravel and loam, stretching from Leigh and Southend,
through Canewdon, Burnham, and Southminster to Bradwell, we
have deposits formed on the western bank of the ancient valley of
the Thames.1
In the discussion on my former paper, Mr. Hudleston pointed out
that the discovery of Boulder Clay at so comparatively low a level
as that of the Homchurch cutting raised a question as to the possibly
pre-Glaciai age of the Thames Valley. On tho other hand, the
position in which the Boulder Clay was found, beneath gravel
belonging to the highest, and presumably oldest terrace of the
present Thames Valley system, seemed to show that the valley into
which it had descended was hardly that of the present Thames.
Consequently, the discover}' of Boulder Clay near Romford on
precisely the samo level, and covered by gravel of the same age as
that at Homchurch, together with the silted-up fragment of an
ancient river-channel of pre-Thamesian age, enables us to reconcile
without difficulty theso apparently antagonistic considerations.
It has, however, been doubted whether the valley of the Lower
Thames shows any signs of the ordinary terraced arrangement
usually found in river-valleys. For my own part I have detected
nothing abnormal in that respect, possibly because, when a worker
on the Geological Survey, it very frequently became my duty to map
river-terraces in rocks of very varying degrees of hardness ; while
1 Geol. Surv. Mem. • The Gteology of London and of Part of the Thames
Valley/ 1889, toI. i. p. 476.
Digitized by Google
Vol. 50.]
RAILWAY FROM ROMFORD TO UPMIXSTEK.
44'J
work of this kind is seldom likely to bo undertaken by a geologist
except as a matter of official duty. On traversing the ground
between Romford and Hornchurch and the Thames, I have never
felt surprised to find that a terrace at a given height could be traced
only for a few yards. Indeed, the material in which the terraces
are cut being London Clay, it seemed to me that nothing else could
be expected. For 1 remember, when in Cumberland, trying to map
some terraces on tho Eden some 3 miles below Carlisle, and failing
to do so for more than a few yards in each case, because they were
cut in sandy, earthy, and clayey gravel belonging to the Glacial
Drift. On the other hand, 8 or 9 miles away, in the valley
of the Esk about Netherby, in a similar lowland, drift-covered
country, and on the banks of a stream of size and velocity like the
Eden, terraces were easily traceablo throughout their course. But
on the Eden, below Carlisle, the harder rock underlying the Glacial
Drift rose perhaps 5 or 6 feet above the level of that stream, while
on the Esk, in the district above mentioned, it might be seen at a
height of more than 20 feet above the river. Similarly, on the
Thames terraces are frequently distinct where it flows through the
Chalk, as at Henley and Remenham, and especially between Cookham
and Maidenhead.1
Again, it was remarked during the discussion on my first paper
on this new railway that the highest river-terrace was not neces-
sarily the oldest. This remark is, of course, a perfectly true one,
and, had I said that the highest terrace was proved thereby to be
the oldest, would have been a useful and timely caution. But I
have always felt that the word proof can scarcely ever be legitimately
used in questions of this kind. We have to be content with a
decided balance of probability. I need hardly remark that thore is
a strong general presumption that the highest terrace is the oldest,
and that the lower terraces may be considered as later and later in
date in proportion as they approximate to tho level of the existing
stream.
The Thames seems to me to show no signs of being an exception
to the rule. A glance at the maps illustrating the geology and
physical geography of South Essex shows how all probability is
in favour of the view that the Thames, from tho beginning of its
existence, has, in this district, been occupied in cutting its way
vertically from a height of more than 100 feet to its present level ;
while horizontally its course has been, in the main, southerly.
In short, the available evidence seems to me amply sufficient to
show that there are no grounds for regarding the Thames Valley as
exceptional in the mode of its formation, and every ground for
supposing the reverse. And I need hardly add that, where the
stratigraphical evidence is as clear as it is in this part of the Thames
Valley, it is almost impossible that it can bo counterbalanced by any
other considerations. Were wo dealing with isolated patches of
1 A map showing tho terraces between Cookham and Maidenhead appears in
Mr. Whiuker'fl memoir 'The Geology of London and of Part of the Thames
Valley,' 1889, toI. i. p. 391.
Digitized by Google
450
MB. T. V. HOLMES BECTIOK8 OS THE KEW [Aug. 1 894,
gravel and loam, lying hero and there on the surface of rocks of
various ages, the evidence of any fossil remains they might contain
might give a presumption of more or less weight as to their affini-
ties. But where we have to consider a connected series of beds
like those of the Thames Valley, we become entirely dependent on
the stratigraphical evidence for information as to the persistence of
any given forms of life, and should not allow mere d priori assump-
tions as to their continued existence, or the reverse, to have any
influence whatever on our deliberation ».
My former paper on the sections seen on the New Railway from
Grays Thurrock to Romford was read on March 9th, 1892. On
May 25th of the same year a very interesting paper, which I had
not the good fortune to hear, was read by Dr. Hicks:1 and this, from
the conclusions favoured as to the age of what I take to be beds
belonging to the Thames Valley systom, demands a brief discussion
here. We may well congratulate ourselves that so important a
series of sections was brought under the notice of so eminent a
geologist as Dr. Hicks ; for, having been made in order to effect
improvements in the sewerage, their existence was extremely brief,
and might easily have been closed before any trustworthy recorder
had had an opportunity of noting their character. From the full
and well-illustrated account of these sections given by Dr. Hicks,
we learn that they varied considerably in detail. In each case there
was at the bottom an eroded surfaco of London Clay. Above this,
hero and there, where the surface of the London Clay was concave,
was a thin stratum of dark clayey loam containing seeds, which bed,
Dr. Hicks remarks, 44 appeared to pass almost insensibly into what
was clearly deeply-stained London Clay with septaria." In this
dark loam some mammoth-tusks were found (22 feet below the
surface), also many seeds of plants living in marshy places or ponds
and (according to Mr. Clement Rcid) existing at the present time
from tho Arctic Circle to the South of Europe. Resting either on
the London Clay or on tho clayey loam was a bed of gravel of
variable thickness ; on the gravel, sand ; and on the sand, clay
with 4 race,' flints, etc. The 4 made ground ' forming the surface
seems to have varied usually from C to 10 feet in thickness.
The height of the surface where these sections occurred is about
80 feet above Ord. dat., or a few feet loss if the 4 made ground '
be excluded. Any one who walks through the straight streets
and open squares of the district in which these sections appeared
cannot fail to notice tho almost perfect flatness of tho ground, which
much resembles that of a broad expanse of old river-drift. And as
consisting of a terraco of old river-deposits this district has been
mapped by the Geological Surveyors.
Nevertheless, Dr. Hicks inclines to look upon these beds as
probably older than the Boulder Clay, because the gravel, sand, and
1 ' On the Discovery of Mammoth and other Remains in Endsleigh Street, and
on Sections exposed in Endsleigh Gardens, Gordon Street, Gordon Square, and
Tavistock Square, London,' Quart. Journ. GeoL Soc vol. xlviiu (1892) p. 463.
Digitized by Google
Vol. 50.] HAILWAF PROM ROMFORD TO T7PALLN8TER.
451
day containing * race ' resemble in their nature and arrangement tho
beds beneath the Upper Boulder Clay of Hendon and Finchley.
But they seem to me to suggest with equal force the gravel, sand,
and clay or loam which are the usual constituents of river-drifts,
and the order in which these usually occur. * Race/ again, may
be found in clays and loams of the most diverse ages. In the
chapters on the Woolwich and Reading Beds in Mr. Whitaker's
memoir on the Geology of London 4 race ' is said to appear in clay
or loam in at least ten different sections. It is also given as a con-
stituent of the river-drift of the Thames Valley at Uford, Erith,
and Crayford. Thus its presence has no particular significance, and
affords no presumption as to age.
Then there is the thin stratum of dark loam in which the mammoth-
remains were found, and which appeared to pass insensibly into
tho London Clay on which it rested. This seems to me to be partly
mud deposited in the channel of the river where the current was
particularly sluggish, and partly material resulting from the contact
of the river-water with the London Clay. Of course, a river is
always tending to shift its course laterally. Thus a part of its
channel where the current was once extremely sluggish gradually
becomes the scene of more rapid motion, and gravel is deposited
where once only mud in suspension slowly descended to the bottom.
From the fact that gravel is usually the lowest of river-deposits wo
learn that any mud settling down where the current is sluggish is
generally swept away when the current becomes swifter, and gravel
is being deposited there. But here and there, in hollows, a little
mud would be preserved, and the carcass of a mammoth, for instance,
sinking into mud at the bottom of a river-channel would form an
obstruction, resulting both in the deposition of an unusual thickness
of mud and in the preservation of the animal's remains.
Again, tho yellowish clay forming the surface-bed at and near
Endsleigh Street, below the * made ground/ seems to me to be the
equivalent of the brick-earth of Ilford and other places in the
Thames Valley which has yielded so many mammalian and other
remains. I am aware that some geologists have shown an inclina-
tion to separate the brick-earths of tho Thames Valley from tho
sands and gravels associated with them, on account of the fossil
contents of the former beds. But it never appeared to mo that
there are any good grounds for such a proceeding. For they were
all alike river-deposits formed contemporaneously, the gravel and
sand having been brought down the river-channel, while the over-
lying brick-earth or clay was simply the inundation-mud which had
spread over tho adjacent flats in times of flood. And it seems
obvious that an elephant or other large mammal, which had become
drowned during a flood, would often be stranded on the alluvial
flat, and his bones remain preserved by later deposits of mud,
showing to observers of the present day every sign of tranquil
deposition. On the other hand, creatures which continued to float
down tho river were extremely unlikely to have their remains pre-
served at all.
Digitized by Google
452 8ECTI0KB FROM ROMFORD TO UPMIN8TER. [Aug. l894t
As the wholo question thus turns on stratigraphies! affinity, not
upon a certain similarity in detail, it can hardly be doubted, I
think, that the position of these Endsleigh Street beds is one in
which river-drift would naturally be expected, and where the
representatives of beds which exist 5 miles away, and 200 feet
above the sea, certainly would not be. And this conclusion, that
they should be classed as river-drift, has also the advantage of
being in accord with the fossil mammalian evidence. For an old
river-terrace, south of Euston Square, with a height of 70 to 80
feet above the sea, may well be nearly equivalent to another at
llford, 9 miles lower down the river, at a height of 40 to 50 feet.
And both in the Endsleigh Street district and at llford the remains
of the mammoth have been found, together with those of the red
deer and horse. But of course the llford pits, which cover mauy
acres of ground and have been worked over during many years, have
yielded many other mammals in addition.
I trust, therefore, that Dr. Hicks will think that some reasons,
at least, have been given here which should cause him to reconsider
the conclusions to which he at present inclines as to the strati-
graphical affinities of these Endsleigh Street beds. For my own
part I would unhesitatingly class them as river-drift of the Thames
Valley system, and consequently as post-Glacial in the sense of
being of later date than the Boulder Clay of Essex and Middlesex.
[For the Discussion on this paper, see p. 4G0.]
Digitized by Google
Vol. 50.J
PLEISTOCEXK DEPOSITS AT TWICKENHAM,
453
29. On the Geology of the Pleistocene Deposits in the Valley of
the Thames at Twickenham, with Contributions to the Fauna
and Floea of the Period. By J. R. Leeson, M.D., F.L.S.,
F.G.S., and G. B. Laffan, Esq., B.Sc, F.G.8. (Read April
25th, 1894.)
In June 1892 excavations were began for the construction of an
effluent culvert from the Twickenham Sewage Works to the River
Thames. The work was commenced at the foreshore of the river,
near the celebrated Pope's Grotto. The Thames is a tidal river at
that point, with a difference of about 8 feet between high and low
water : the low-water line is 5 feet above Ordnance datum. The
excavations commenced at low-water level on the Middlesex bank
of the river, and were continued in a north-westerly direction, with
an incline of 1 in 500, through certain roads and lands towards the
Sewage Works. The length of the section was about one mile, and
the width of the cutting was 4 feet 6 inches. The sloping bank
between the river and the Kingston main road consisted of soft,
loose material, which had evidently been deposited there in modern
times. After crossing under the main road, distant about 60 yards
Fig. 1. — Plan showing the position of the sewer-cutting in the
Valley of tl\e Thames at Twickenham.
From From
Shcpperton. Staines.
From To
Kingston. Waterloo.
from the river, the excavation, which at this point was about 10 feet
deep, entered into the reddish-yellow gravels which abound in this
neighbourhood. It was then continued for some distance through
these gravels under a roadway called Pope's Grove, at depths
varying from 12 to 19 feet. A considerable quantity of water was
found in the excavation, and had to bo pumped. Beneath the
gravels was the London Clay, which was met with in the excavation
at two points, and in one place was penetrated to a depth of 5 feet.
After leaving the London Clay tho excavation was continued
through gravel alone for a short distance, and then a dark loamy
Digitized by Google
464
PLEISTOCENE DEPOSITS AT TWICKENHAM.
[Aug. 1894.
bed was found at the bottom of the cutting, about 12 feet below
the surface of the roadway. The point where the dark bed was
first touched was 420 yards from the river, and throughout the
remainder of the section, which was continued through other roads,
this dark bed was found more or less at or near the bottom of tho
cutting — at depths varying from 11 to 18 feet below the surface of
the ground. At two points where ' sumps ' wore sunk for purposes
of pumping, this dark bed was cut right through, and gravel in
every way similar to that above was found beneath it. The
thickness of the dark bed at these points was found to be 2 feet
6 inches and 2 feet 3 inches respectively, but it must have been
thicker in some parts, for it was entered to a depth of 3 feet in one
place without reaching the bottom.
In vol. xlviii. (1892) p. 453 of this Journal, a description is
given by Dr. Hicks of a dark loamy bed found beneath the gravels
in the bottom of excavations in the neighbourhood of Endsleigh
Street in which organic remains were found. The bod itself
appears to bear a resemblance to that found in the gravels at
Twickenham ; there is also considerable similarity in the flora
found in each, as will be shown farther on, but the dark bed in
Endsleigh Street was believed to lie directly on the London Clay.
This clearly was not the case with the dark bed found at Twicken-
ham ; it intervened between beds of gravel, and was itself evidently
of very limited thickness throughout.
The material composing the 4 dark bed ' found at Twickenham
varied somewhat. In some places, especially where the bed attained
its greatest thickness, it was of a soft, slimy nature, like river mud,
whereas in other places it was much coarser and somewhat sandy
in character. After exposure to the atmosphere the finer por-
tions formed into compact clayey lumps, whilst the coarser parts
became more disintegrated and had the appearance of earth or loam.
It evidently contained a large proportion of decayed vegetable matter.
When treated with water the finer samples left little or no residue,
but from the others there was a considerable amount of sandy
deposit. A chemical analysis gave the result tabled on p. 457.
Immediately above the dark loamy bed thcro appeared to be a
layer of dark blue or greyish sand and gravel, which had very much
the same appearance as the dredgings now taken from the river,
and known as 4 Thames ballast.' This layer of dark gravel was of
varying thickness, and in some places was scarcely distinguishable,
if not altogether absent. In no place did it attain any considerable
thickness, and it appeared to die gradually away into tho yellow or
reddish gravel above it. It seemed as if the bed of dark loam had
discoloured to some extent tho gravel in contact with it. Throughout
the gravels generally no organic remains were found, but the dark
bed of loam was very rich in indications of animal and vegetable
life. All the fossils found in the excavations were discovered either
in the dark bed of loam or in the gravels immediately above it.
The annexed sections (figs. 2 & 3) show the structure of the ground
in question and the position occupied by the dark-blue loam seam.
Digitized by Google
" End of i*ctioti.
Rood crosses.
DARK LOAM BED.
DARK LOAM BED.
Sump-holt'.
Bend in section.
— Railway cro-sea.
DARK LOAM BED.
LONDON CLAY.
LONDON CLAY.
Roa*l crosses.
River Thames.
1
r
?
?
2
Digitized by Google
456
DR. J. B. LEE80N A5D MR. O. B. LAPFAN OK
[Aug. 1894,
There can be no
doubt that this layer
of dark-blue loam is
purely a local one. In
two well- sections at
Isleworth, quoted in
Whitaker's * Geology
of London,' Mem. Geol.
Surv. 1889, vol. ii.
p. 121, no mention
of it is made ; and,
coming nearer home,
wo find that it is
also absent in a
recent well-section at
Messrs. Burrows and
Cole's Brewery, near
Twickenham Railway
Station, \ mile east
of the present section
(op. ext. vol. ii. p. 170);
while the description
of an oxtensive cutting
in the Thames Valley
Railway, \ mile to
the westward (op. at.
vol. i. p. 394), does
not mention anything
about it. These facts,
in conjunction with
what will be shown
farther on from the
seeds found in the
loam, appear to indi-
cate that we are deal-
ing with the deposit
of a small local lake
lying in the midst of
the Thames gravels,
Fig. 3. — Sections of the tump-holes in the
gravels at Twickenham.
a
Jr
B
•>
a
X
' "
m 9
a • » •
* » m * •
* k«
*' I * '
9 9*
* » ' » »
*'*'9 '
» • *
" « 9' -
^« * a "
* Mi *
• « •
* m 0 -
m 0 r .
: 4%;
ti ■ • *
* -j * *
r.v 9 ~
» 9 m
Coarae
re<ldi.h-
yellow
— —_rz\ Discoloured
gravel*.
Dark loam-
Coarac
grarel.
Coarse
[Vertical Scale : 1 inch = 4 feet.]
while the fact of its erosion and its unconformability to the gravels
above indicate that we are dealing later on with an old land-
surface.
Our interest in the deposit was aroused by finding, in the first
instance, reindeer-horns in the gravels, near the commencement of the
cuttings. The London Clay then cropped up for some distance, and
nothing more was found, till a \ mile farther on the bones of Bison
and Bos longifrons (or Bos taunts) were discovered lying on the top
of what proved to be our * dark loam 1 layer. A diligont search
was made in this loam for some further evidences of organic
remains, but without success ; and thinking that its dark colour
Digitized by Google
VoL 50.]
PLEISTOCEN'F. DEPOSITS AT TWICKENHAM.
457
might be due to free carbon, a sample of it was submitted to
Mr. William Chattaway, F.I.C., along with one from the lighter-
coloured sand above, to see if any further light could be thrown
upon it by the chemist. The subjoined analyses, together with
Mr. Chattaway 's remarks which accompanied them, showed that
there was every reason for continuing our search for organic re-
mains.
Moisture
Combined water
Organic
SUica. ........
Ferric oxide
Alumina ...
Lime
la and potash
Carbon dioxide i combined)
Sulphuric anhydride
Chlorine
A.
Reddish-yellow
Sand from above
Dark Loam Layer,
Pope's Grove,
Nov. let, 1892.
Dark Loam Layer
Pope's Grove,
Nov. 1st, 1892.
•21 per cent.
1H>8 percent.
trace.
•31 „ ,.
04 „
>•
94-40 ,.
•1
6511 „ „
1-7C „
>»
1-28 „ „
2 73 „
n
2 66 „ „
•23 „
r»
8*78 „ ,,
16 „
it
•40 „ „
trace.
trace.
•19 „
i»
7 03 „ ,.
26 ,.
u
'33 „
trace.
distinct trace.
99 98 per cent.
99 94 per cent.
The following observations accompanied the analyses : —
(1) The lime is probably wholly present as carbonate in sample
B ; but in sample A it may probably be present as sulphate.
(2) The organic matter in B is largely carbonaceous, but Mr.
Chattaway has not fully satisfied himself of its nature.
(3) There is probably only magnesium carbonate in the case of
A, for, singularly enough, the amount of carbon dioxide found will
exactly combine with the magnesia. That base is probably also com-
bined with C03 in B.
(4) By 4 combined water ' is meant that which is not lost at a
temperature of 100° C, but is held chemically, or else in some mole-
cular way. This was of course determined by heating the sand to
redness, and collecting the water in a tube packed with calcium
chloride.
Later on we were abundantly rewarded by finding numerous
shells, seeds, and much vegetable debris.
Extensive washings were made of the loam by Mr. H. M Bennett,
and they were submitted to Mr. Clement Reid, F.L.S., F.G.S., who
kindly determined them for us as follows : —
Digitized by Google
458 DB. J. R. LEE80N AND MB. G. B. LAFPAN ON [Aug. 1 894,
Mollusca from Twickenham.
Ancylus fluinatili*, Mull. Valvaia piscinaiis. Mull.
Limnaa peregra, Mull. Pisuiium amnicum, MiiU.
Planorbis albus, Mull. piunUum, Gmel.
Bythinia tentaculata, Linn. Spharium corncum, Linn.
Plants from Twickenham.
Stdlaria media, Cyr.
^lontia fonUxna, Linn.
Hcraclcum Sphondyliutn, Linn.
GaUopsis TetraAU, Linn.
AtripUx sp.
Polygonum Pcrsicaria, Linn.
Rumex crispus, Linn.
Potamoqeton rufescens, Schrad.
Zannichtllia palustris, Linn.
Elcocharis palustris, E, Br.
Scirpus lacti&tris, Linn.
Carcx panicca, linn.
sp.
Phragmites.
The whole of the 8 species of mollusca and the 14 of plants are
still living in the neighbourhood. They point, as Mr. Reid remarks,
to swampy ground and a small pool or channel rather than to
runniDg water or any large stream.
Lying just upon the layer of dark loam were found scattered
all along the section a great number of mammalian bones, about
300 altogether, which were carefully preserved and sent for deter-
mination to Mr. A. 8mith Woodward, Assistant Keeper of the
Department of Geology, British Museum (Nat. Hist.), to Mr. E. T.
Newton, F.R.S., of the Geological Survey, and to Prof. Charles
Stewart, P.L.S. The following species were identified : —
Bog longifrons. Sus scrofa.
taunts. Cervus elaphus.
Cennts capreolus. Canis lupus.
Eang\fer tarandm. \ Bison priscus.
Much interest was aroused with regard to the bones of the Bos,
Mr. Smith Woodward, Mr. Newton, and Prof. Stewart considering
them to belong to Bos longifrons, while Prof. Boyd Dawkins, F.R.S.,
to whom some of them were sent, affirms them to be * Bos taurus,
a domesticated variety larger in the horns than the actual strain of
Bos longifrons? 1
A noticeable point in connexion with the femora and humeri, the
marrow-bones of the bison, was that in most cases the bones were
broken, and the shaft split or cracked as if from direct violence,
and this suggested to Dr. Gunther, P.R.S., of the British Museum
1 [It haying been objected that the Authors, when referring to the occurrence
of the remains of Bison priscus and Bos longifrons lying on the top of the
dark layer of lonm, seem to convey the impression that the two animals were
contemporaneous, whereas throughout the Thames Valley deposits Bos longi-
frons is always referred, and justly so, to a much later date than Bison jrriscus,
the Authors of this paper wish, in reply, to state that they have no theory upon
the subject. The bones were collected by the navvies, as they were found,
according to their statements, just on the top of the dark loam-layer, and put
into a sack until tbey were handed to the Authors. Whilst on the one hand
there is no reason to doubt the accuracy of the men's statements, there is on
the other no desire to elevate them to the standard of skilled observers : the
facts must be taken for what they are worth.— May 15th, 1894.]
Digitized by Google
Vol. 50.]
PLEISTOCENE DEPOSITS AT TWICKENHAM.
450
(Nat. Hist.), the work of human hands. It is a curious fact that
only the marrow-hones had been so damaged, the more solid meta-
tarsal and metacarpal bones (devoid of marrow) being undamaged
and entire. The frontal bones of the Bos are all broken up in a
definite and peculiar manner, and the cranial bones fracturod into
many small pieces, nor could any large toothmarks upon the bones
be found which might have explained the fracturing as duo to beasts
of prey. Looking at the bones themselves, there would seem to be
very little doubt that these fractures indicate the presenco of man,
were it not for the fact that Mr. Clement Kcid has informed us that
the same thing is frequently seen in the long bones of the Cromer
Forest Bed, where the agency of man is out of the question.
Nevertheless, it is exceedingly difficult for us to believe that so
many bones could have been fractured in so definite and apparently
purposeful a manner without enlisting the factor of human agency,
especially as the presence of man in England at a time anterior to
these deposits is not disputed.
No flint-implements, however, have been found in the Twicken-
ham gravels, although carefully and constantly searched for. Yet
they have been found in fairly large numbers dredged from the
Thames in the immediate vicinity, along with the bones of animals
now living, and are all of the Neolithic type ; but the undisturbed
gravels are quite barren in this respect.
Of the Twickenham seeds determined by Mr. Clement Reid, one
half of the species aro the same as those discovered by Dr. Hicks in
Endsleigh Street (which were also determined by Mr. Clement Reid)
and declared to characterize marshy places and ponds.1 The mol-
lusca are far more abundant at Twickenham, we having 8 species,
whereas Dr. Hicks had only 2. Tho vertebrates are very different,
Cervus tlaphus being the only one common to both sections.
In connexion with the fauna of the district, and as throwing some
light upon the conclusions at t ho end of this paper, we may mention
here that the bones of rhinoceros have been found at Twickenham,
20 feet below the surface, in sand, at Messrs. Bennett and Hawkins's
Nursery Grounds, in digging for a deep well ; and 8 feet above them,
that is 12 feet from the surface, were found the bones of the horse
(Equus cuballu*). Theso would be \ mile to the east of our present
section, while \ mile still farther east the original specimen of the
Saiga antelope (Saiga tartarica) was discovered in sand below
tho superficial gravel, 7 feet from tho surface, and presented to the
British Museum — it was tho first evidence of the occurrence of this
animal in Pleistocene Britain.
Conclusions.
The gravels at Twickenham which, up to the time of this cutting,
have been regarded as uniform, indefinite, and almost destitute of
organic remains, are now shown to contain a varied fauna and
flora, suggestive of great climatic and other changes.
1 Quart. Journ. Geol. Soc. rol. xiviii. (1892) p. 458.
Digitized by Google
460
PLEISTOCENE DEPOSITS AT TWICKENHAM.
[Aug. 1894,
They can be divided into four zones : —
(1) The lowest and deepest, the * coarse ballast gravel,' which
suggests a rapid torrent at the time it was laid down.
(2) The layer of 4 dark sand,' sparsely scattered with gravel,
which indicates a slackening of the stream.
(3) The dark-blue loam Beam which points to a further slackening
of the current, the plants and shells all now living in the
neighbourhood and indicating a climate like the present.
The diminishing velocity of the stream in these three zones sug-
gests a continuous lowering of the land, and may, therefore, point
to the termination of a continental period.
There is evidence of an old land-surface, on the top of the blue loam
seam, over which roamed the bison and the reindeer, and as these
animals do not occupy the same areas at the same time, it points to a
changing climate of long cold winters, during which the reindeer
came south, and short hot summers, when the bison would move
northwards.1
The bison-bones indicate the very probable presence of river-
drift man.
(4) The overlying coarse reddish-yellow gravels, with (towards the
bottom) reindeer bones only, and large flints such as could
have been carried by ice alone, indicato a much colder
climate, probably Arctic (a supposition which is confirmed
by the Saiga antelope having been found in this layer
in the same district in 1891).
Discussion (on the preceding two Papers).
The President congratulated the Authors of the second paper on
having succeeded in rescuing so interesting a collection of remains of
Thames Valley mammalia. He inquired if Dr. Leeson had obtained
the remains of the Saiga antelope from the same horizon as the prosent
4 finds,' and if so he pointed out that these remains — i.e. the Bison
2iriscu8, the Rangifer tarandus, and the Saiga antelope — represented
the older fauna of the Thames Valley gravels and brick-earth.
Sir John Evans expressed his pleasure at Mr. Holmes's further dis-
covery of evidence as to the superposition of the old Thames Valley
gravels upon the Boulder Clay, as these discoveries supported the view
he had always held, that these gravels, whether at a high or at a low
level, were 4 post-Glacial' in the sense indicated by the Author.
The finding of the mammalian remains by Dr. Leeson in the low-
level gravels at Twickenham was of interest, as proving the existence
of the reindeer and bison in the Thames basin at the time of the
deposition of these beds. As to some of the remains of other animals,
however, ho entertained doubts whether, though found in the course
of the excavation, they really belonged to the gravels.
Prof. T. MCK. Hughes was pleased to hear Mr. Holmes bring
forward such direct proofs that tho mammoth-gravel of the Thames
Valley was post-Glacial. He thought that the bones exhibited by
1 See Boyd Dawkins, ' Early Man in Britain,' pp. 189, 191.
Digitized by Google
Vol. 50.] AND SECTIONS BETWEEN T7FMIN9TER AND ROMFORD. 401
Dr. Leeson and Mr. Laffan might be divided into two groups,
(1) those with bison, and (2) those among which the small ox and
dog or wolf occurred. Group 2 he thought might be further distin-
guished as («) the heavy black bones from the silt, and (b) some
d>irk-coloured, light-weighted bones, the origin of which was open
to suspicion. He urged that it was quite impossible that group 1
could be newer than group 2, but suggested an explanation of
the section which would get over the difficulty, namely, that there
was an ancient irregular channel excavated in the older /toon-gravel,
and running north of the boss of London Clay shown in the section,
and that in this channel the newer black silt had been laid down.
He pointed out that the mollusca were all such as now live in our
rivers, two out of the eight being named fluviatili* and amnicum
from that fact. He questioned the possibility of distinguishing a
small domestic ox from B. longifrons by a fragment of a metatarsal,
or a wolf from a dog by one Limb-bone, and thought that all the
small dark-coloured horn-cores were those of domestic cattle.
Mr. E. T. Newton remarked on the interest attaching to this
new discovery of such abundant remains of reindeer in the Thames
Valley gravels to the west of London ; a species which, as Prof. W.
Boyd Dawkins had pointed out, had not been met with in these
gravels eastward of London. With regard to the single bone of Bos
longifrons, he could not accept it as good evidence of the occurrence
of that form in the same bed with bison and reindeer, and felt
sure that it must have been derived from some newer deposit.
Mr. Lewis Abbott could not help thinking that Mr. Holmes had
been very bold in attempting to construct a river some 80 miles
long from a single section. The Boulder Clay was coincident
with the present valley and occurred at various heights down to
about 50 feet on tho northern side, and lower still on the southern
side : if that did not indicate a valley, ho failed to see what would.
But why a pre-Thamesian date was claimed for it he could not
understand. That the Boulder Clay extended into the Thames Valley,
and even over it, was evinced by the large number of Northern fossils
and rocks found south of that river. He considered the paper one
of great interest and importance.
Referring to Messrs. Leeson and Laffan *s paper, he could not agree
with the lacustrine origin of the beds under consideration. The list
of mollusca commenced with a genus which would almost settle this
point : the facies was not lacustrine but sluggish-water, nor was the
coarseness of the gravels consistent with a pond or lake origin. The
section was, in almost all respects, similar to that exposed at the
new Admiralty Offices, where a lateral ridge had existed ; upon
the hugging of the southern shore by the stream a backwater was
left, where a sediment of a more muddy nature was laid down : in
this the unique animal-remains were deposited. It was at about
the same relative level as that of the Admiralty which produced
Saluv polaris, and was probably of the same age. At the Admiralty
section the upper gravels were in all probability much newer than
the lower beds, and he ventured to think that also was the case in
this instance.
Q. J. G. S. No. 199. 2 i
Digitized by Google |
462 PLEISTOCENE DEPOSITS DISCUSSION. [Aug. 1894,
Mr. G. B. Lafpan said that most of the bones referred to in the
paper had been collected by him personally, and he pointed out on the
section the position in which these bones were found. They all came
from the bottom of the cutting, either from the dark bed of loam itself,
or in close proximity thereto. In the first part of the section no
fossils were found, but immediately the dark bed was reached
organic remains were discovered in large quantities. For a con-
siderable distance through the cutting they were found, and always
at about the same depth from the surface. There was nothing in
the circumstances under which they were found to support the
suggestion of Prof. Hughes that some, such as the bones of the
bison and reindeer, were from a layer different from that whence
the others, such as Bos longifrons, came. No difference whatever
was noticeable in the gravels, and the bones were found in every
instance either embedded in the dark layer itself or immediately
above it. Several sections have been made in the gravels in the
neighbourhood of Twickenham, and the London Clay is usually met
with at depths of 15 to 30 feet below the surface of the ground.
Organic remains are very- rare in the gravels overlying the London
Clay. The large quantity of bones, seeds, and shells found in con-
nexion with this dark bed of loam makes the layer one of some
interest to geologists, an interest which is increased by a com-
parison with the dark bed discovered two years ago in Endslcigh
•Street, described by Dr. Hicks at a previous meeting of this
Society, and in which very similar organic remains were found.
Prof. Hull, having seen the sections near Upminster, quite
concurred with Mr. Holmes that they showed old Thames Valley
gravel resting on Boulder Clay. He wished to refer to the changes
in relative levels of this part of England and of the outer sea, in-
dicated by the old river-gravels — both those of Essex and those of
Twickenham described by Dr. Leeson. It was probable that these
gravels were representative of each other on either side of the Thames
Valley, and as the surfaces of the terraces formed by them gradually
rose inwards to about 200 feet near Egham and Windsor, they must
have been deposited when the land was lower than at present by
about this amount. During the process of re-elevation, the river
cut back and deepened its channel until the present physical con-
ditions were established.
Dr. Leeson said that the Saiga antelope had been found in the
gravels at Twickenham about £ mile east of the present section,
and that these gravels were continuous with those now described.
Tho Saiga was, however, much nearer the surface. With regard
to the bone of Bos longifrons, about which so much interest had
been excited, he could only say that it was brought to him by
the same workmen as those who had brought the reindeer and
bison, and that tho bones were all mixed together in a sack. Ho
saw no reason to question the one occurrence more than the other
and could vouch for the strata in which they are all said to have
been found being undisturbed ground.
Mr. T. V. Holmes briefly replied to the remarks made on his paper.
Digitized by Google
Vol. 50.]
THE PERMIAN BRECCIAS OF THE MIDLANDS.
463
30. A Comparison of the Permian Breccias of the Midlands with
the Upper Carboniferous Glacial Deposits of India ami
Australia. By R. D. Oldham, Esq., F.G.S., Superintendent,
Geological Survey of India. (Read June 6th, 1894.)
Co.VTBHTS.
I. Introduction 4«»3
II. The Permian Breccias of England 4«3
III. The Indian and Australian Lpper Carboniferous Boulder-beds 4(56
IV. Conclusion 470
I. Introduction.
In 1855 the late Sir Andrew Ramsay read before this Society a
paper 1 on the Permian breccias of Enville and of the Clent, Abberley,
and Malvern Hills, in which he gave his reasons for believing that
they wero deposits of glacial origin. This was followed in 1875 by
a paper of the late Mr. H. F. Blanford,3 in which the suggestion
was made' that the Talchir boulder-beds of India, whose glacial
origin had been recognized in 1856,* might have been formed during
that glacial period the traces of which had been preserved in the
Permian breccias of England.
The glacial origin of these breccias has frequently been disputed,
and the doubts cast on them have been to a certain extent reflected
on the Indian deposits to which a similar origin has been ascribed.
No actual comparison of the two by any observer acquainted with
both had, however, been made, and I determined to take an oppor-
tunity of visiting some of the exposures with a view of comparing
the English and Indian rocks. The opportunity came last Easter,
and I have to express my obligations to Mr. Wickham King, F.G.S.,
who has made a special study of the deposits, and was good enough
to guide mo to the principal localities and the best exposures.
II. The Permian Breccias of England.
The grounds on which the late Sir Andrew Ramsay based his
belief in the glacial origin of the beds were, stated briefly, (1) the
distance from which the included fragments came, their source being
considered to lie in Shropshire and Montgomeryshire 5 ; (2) the
large size of some of the included blocks ; (3) the presence of
smoothed and striated surfaces, like those produced by glaciers, on
some of the rock-fragments.
As regards the source of tho included fragments, later researches
seem to have invalidated the conclusion that they came from a
1 Quart Journ. Oeol. Soc. vol. xi. pp. 185-205.
2 Op. cit. vol. xxxi. pp. 519-540.
s Ibid. p. 528.
* Mem. Geol. Surv. Ind. vol. i. pt. i. p. 49.
8 Op. jam cit. pp. 191-193.
2l 2
Digitized by Google
4fU
MB. B. D. OLDHAM ON THE
[Aug. 1894,
distance. Mr. Wickham King has for several years been carefully
searching the various exposures, and making a collection of the
various rocks of which the breccia is composed. His results have
in part been published,1 and a further contribution being in pre-
paration I shall not attempt to deal with this aspect of the deposits.
Leaving this Line of investigation, and coming to my own observa-
tions, the breccias, wherever they arc exposed, are composed of more
or less, but never very much waterworn, sub-angular fragments of
various sizes; the deposit is always rudely stratified, the various
beds generally shading off into each other and not continuing as a
rule for any great distance. On Abberley Hill, where the breccia has
a coarser grain than any other exposure that I saw, there is a bod of
red sand interstratified with the breccia near the upper limit of the
quarry, and the material bears evident traces of having been re-
arranged by running water, but none of having been deposited in a
tranquil sea.3
A comparison of the various exposures throws some light on the
direction of travel of the included fragments. Church Hill is some
(i miles west of Abberley, and is mentioned by Sir A. C. Ramsay 3
as a locality where tho stones are unusually angular and broken, and
the breccia contains large boulders ; since his time, however, a large
quarry, opened in this hill, has shown that this is not the case.
Not only did wc fail to find any block exceeding a cubic foot in
bulk, and only a very few at all approaching this size, but there is
a very large proportion of sand and fine gravel (less than an inch
in diameter) ; and the smaller fragments are all considerably water-
worn, though still imperfectly rounded. At Abberley, on the con-
trary, there is a very much smaller proportion of fine gravel, and
large blocks over a foot across are fairly numerous, the largest block
at present to be seen measuring 2' 7" X 1' 5" x 1' 5". On the Clent
Hills there is the same contrast between the south and north ends :
to the south large blocks are numerous, to the north the rock be-
comes finer-grained and the constituent fragments more waterworn.
The rock in fact, whether we regard each exposure separately,
or the relation of one to another, exhibits all those characteristics
which may now be seen in the great gravel-fans that are found
everywhere along the foot of the hill-ranges of the drier parts of
"Western and Central Asia.4 They form a continuous fringe along
the foot of the hills, often extending many miles over the plains ;
at their upper end they are mostly composed of large fragments, the
interstices being filled with small gravel and -sand, but farther from
the hills the larger fragments are for the most part left behind and
the general texture of the deposit is finer. The pebbles, even to the
outermost limit, generally remain imperfectly rounded, for when the
1 ' Midland Naturalist,' vol. xvi. (1803) pp. 25-37.
2 Two very good photographic views of the breccia are given in Mr. Wickham
King's paper, op. gupra cit.
3 Quart. Journ. Geol. Soc. vol. xi. (1855) p. 193.
4 Those of Persin have been dc^cri bed by Dr. W. T. Blanford, F.R.S., Quart.
Journ. Geol. Soc. vol. xxii. (1873) pp. 496, 498.
Digitized by Google
Vol. 5o.]
PERMIAN BRECCIAS OF THE MIDLANDS
405
streams flow after rain they are generally so loaded with debris as
to be rather of the nature of fluid mud than water, and in this the
fragment*) of rock seem to be carried along en masse without being
worn against each other to the same extent as in a mountain
torrent. The stream, in fact, flowing over a surface of its own
formation, has developed such a slope and shape of bed that it is
only able to transport its burden, and has little or no surplus energy
to devote to the rounding of the rock-fragments. Another effect of
the large proportion of mud and stones moved by the streams is that
occasional large blocks travel in the moving mass, far beyond where
most of their fellows have been left behind ; occasional exceptional
floods too may bring down larger blocks than usual, which afterwards
get covered up by and embedded in gravols of much smaller grain.
To such a cause I would ascribe the deposition of the Permian
breccias. That is to say, they were formed by the action of streams,
subaerially, and in the immediate proximity of the uplands from
which these streams drained. The deposit is too well bedded, and
the fragments are often too much waterworn, to be au actual talus,
or a landslip formation, extensive as these may sometimes be ; it is
not sufficiently regularly-bedded to be a marine deposit formed in a
tranquil sea, into which fragment* of rock were dropped by floating
ice ; it does not exhibit any of those disturbances of bedding found
in the marine boulder-clays of Pleistocene age; and the very local
character of the rudely defined strata, the way they pass into each
other, combined with the general regularity and parallelism of
bedding, seem to proclude the idea that they could have been
deposited in a turbulent sea without the agency of tioatiug ice, or
formed by a debacle. There remains but the supposition that they
were formed subaerially, like the analogous deposits of recent gravel-
fans, and in this case the angularity or at most imperfect rounding
of the fragments precludes their being of any but local origin.1
Though the hypothesis of transport by floating ice must be
abandoned as an explanation of these deposits, in favour of a mode
of origin little understood when Sir Andrew Ramsay wrote his paper,
this in no way affects the question as to whether the striations seen
on some of the included fragments were produced by glaciers or not.
To this point I devoted some attention, and the results may, perhaps,
be not altogether unacceptable.
The locality where striated stones are most abundant, and their
mode of occurrence best observable, is the quarry on Abberley Hill.
This, and that on Church Hill, are the only two which are cut deep
enough to reuch the un weathered portion of the deposit. Generally,
the quarries only take off the surface-skin of soft and weathered
material ; on Berrow Hill the quarry cuts a little deeper, and here, as
1 The same conclusions, regarding the local origin of the materials of which
these breccias are composed, hate been independently reached ^ by previous
observers. See Beete Jukes, 4 The South Staffordshire Coalfield,' Metn. Geol.
Surv. 2nd ed. (180D), p. U, and .Mr. Wickhaui King's more detailed researches,
a* already quoted.
Digitized by Google
466
MB. R. D. OLDHAM OX THE
[Aug. 1894,
on Woodbury Hill, I found some striated fragments, but neither so
abundant or distinct as at Abberlev. On the Clent Hills there are
no quarries, and the fragments lying on the surface are too weathered
to show the finer stria?, if they ever possessed any, while it is im-
possible to say when or how the coarser ones were produced.
Abberley Quarry is consequently the only one where satisfactory
observations can be made, and the following remarks must be
understood to refer to it and to that portion where the quarry-face
exposes the unwcathered rock in situ. Striated fragments can be
found in other places, but some of the points to which impor-
tance must be attached cannot be observed.
Fragments showing a certain amount of striation are not un-
common, though by no means universal ; the striated fragments did
not seem to me more abundant than might be expected in glacial
debris, less so, in fact, than in some deposits whose glacial origin is
indubitable. The formation, however, consists of fragments of rock
of all sizes lying in contact with each other, and as the dip of the
beds and the slight deformation of some of the fragments show that
they have undergone some disturbance, it might be urged that these
striations were produced subsequent to accumulation. There are
consequently two separate questions to be considered, namely,
whether the stria? were produced before or after the embedding of
the fragments on which they were seen ; and whether, if they were
formed previous to deposition, they were more probably formed by
glaciers or by some other agency.
There are some markings to be found which must have been
formed by the pressure of adjacent pebbles, such as pittings, not
unlike those of the pebbles of the Bunter conglomerate and the
Nagclfluh. There are also scratches due to earth-movements sub-
sequent to deposition ; but, excluding these, one may also find a fair
number of fragments exhibiting a number of parallel scratches, not
infrequently crossed obliquely by others, and many of the individual
scratches can be distinctly traced for a couple of inches and more.
These seem too long to be accounted for by any movements that can
have taken place in the body of the rock, for it must be remembered
that to produce a number of close-set stria) running across the face
of a pebble requires an amount of total movemeut exceeding many
times the length of the individual stria?. I repeatedly searched to
see if there were any trace in the body of the rock of shearing-
surfaces corresponding to the striated surfaces on the individual
fragmente, but failed to find them. Further, there did not seem to
be any regularity in the direction of the stria) ; certainly, where a
broad surface of a fiat fragment was striated it was generally found
more or less parallel with the bedding, but this is what would
naturally occur in a stream-deposit. On other fragments the striated
surfaces lay at every angle with the bedding, and the directions of
the stria? in every azimuth. Moreover, it often happened that only
the projections, such as one of the worn-off angles, were striated,
while the rest of the stone was unmarked, a featuro which is easily
explicable if the striation had been anterior to deposition, but would
hardly be expected if it had been produced subsequently. For these
Digitized by Google
Vol. 50.]
PERMIAN BRECCIAS OF THE MIDLANDS
4«7
reasons it would seom that, with some exceptions, the striation of
the fragments was anterior to their deposition, and this conclusion is
upheld by an examination of the Church Hill quarry. Hero a careful
search failed to yield any good specimens of striation, but on a few
of the fragments a careful examination revealed some traces, as if of
once deeply-marked scratches nearly obliterated. As has already
been explained, the Church Hill exposure consists of more waterwom
material than the Abberley, and, under these circumstances, it is
only natural that striatious on the pebbles should be absent, if those
at Abberley were produced anterior to deposition ; while on the other
supposition it is difficult to see why they should not be as common
at the one place as at the other. On the Clent Hills the only toler-
able exposures I saw were in the finer and more waterworu type of
deposit, and here, too, striations were not to be found.
But if the scratches were produced before the fragments on which
they are fouud were deposited in their present situation, the only
two agencies that could havo been concerned are glaciers or move-
ments of the soil-cap. Tho soil-cap, cither moving gradually down
a hillside or when precipitated as a landslip, may certainly produce
marks on the subjacent rock which it is difficult, and sometimes
impossible, to discriminate from those produced by glaciers, but it
is at least doubtful whether it cau produce a close and parallel
striation of loose fragments such as is seen in many of the fragments
at Abberley. The fragments which havo retained the striations are
all of hard rock, mostly of rhyolito or rhyolitic ash, and these
striations can only have been produced by a steady movement
accompanied by great pressure ; the stone which produced the
scratch must, in fact, have been held firmly and pressed hard against
the fragment that was scratched, and I am not aware that any ca*e
has been observed of loose fragments in a scree or landslip being
scratched in the deep and regular manner that is seen on many of
the Abberley stones.
Another consideration to be borne in mind is that these effects of
soil-cap movements are only locally developed, and that the Abberley
rock is certainly not the direct effect of a landslip or talus, but the
deposit of a stream. Under such circumstances it is difficult, even
if loose fragments could occasionally be scratched by soil-cap move-
ments in the manner these are, to see how they could be so abundant
as they are in this quarry ; while, if the deposits were composed of
rearranged moraine-material, their abundance is by no means too
great to be explicable : and this seems, on the whole, to be the most
probable explanation of the Abberley deposit and of the very similar
deposits on Woodbury and Berrow Hills.
It is only by a consideration of the combination of characters
exhibited by a deposit that one can come to a correct conclusion
regarding the origin of such a rock as this is. Not a few of the
striated fragments I have seen are such as would most unhesitatingly
be accepted as truly glacial, if they were found in a recent moraine
or in a Pleistocene boulder-clay; many are of a more doubtful
character, but not more so than specimens that might be collected
out of a bouldcr-clay of indisputably glacial origin ; while it would
Digitized by Google
468
MR. R. D. OLDHAM OK THE
[Aug. 1894,
be impossible to collect a specimen, even from one of these last-
named deposits, for which, taken as an individual specimen and
apart from its surroundings, it would not be feasible to suggest
some other plausible explanation of origin.
Whether the supposition of the glacial origin of the striated frag-
ments bo accepted or not, it will in no way affect the subaerial origin
of the breccias and the local origin of their constituents. If it be
accepted, the Abberley beds, and those of other localities too, would
have to be regarded as deposits analogous to the * rjlacial-schotUr'
of Germun geologists : that is to say, as a mixture of moraine and
scree-material, transported and deposited by streams.
III. The Indian and Australian Upper Carboniferous
Boulder-beds.
I now come to the comparison of the rocks just described
with those boulder-beds of Upper Carboniferous age in India and
Australia which are regarded as glacial by observers who have studied
them in the field. Contrast would, indeed, be a more fitting word
than comparison, for I may begin by saying at once that there is
not the slightest real resemblance between the two. The English
beds consist of a mass of fragments of stone of all sizes, mixed
together and resting in contact with each other ; the Indian and
Australian beds, on the other hand, where typically developed, have
always a tolerably, often an extremely fine-grained matrix, itself
distinctly stratified, or interstratified with well-bedded rock. Through
this are scattered in abundance blocks of rock of all sizes, but always
embedded in, and well separated from each other by the matrix.1
Where this is finely laminated, as is sometimes the case, the bedding
may be observed to bend down under aud arch over an included frag-
ment, as is seen where a volcanic bomb is embedded in a stratified
tuff.
The characters of the rock are, in fact, such as can only be
explained by a deposition of the fine-grained matrix in quiet water,
into which the large included fragments were dropped from above.
The abundance of these is too great to be explained by the action of
drift-wood ; volcanic agency is excluded by the absence of any con-
temporaneous volcanic beds ; and the only known agency adequato
to explain the facta is float ing ice. That this is the true explanation
is confirmed by the fact that in several places the included frag-
ments show smoothed and striated surfaces exactly similar to those
produced by glaciers, and in two localities in India the underlying
rock shows the same smoothed, scratched, and roche-moutonnee
character as iB produced by glaciers.
This summary of the characters of the Indian and Australian
1 A sketch of the Talchir boulder-bed given by C. L. Griesbach, Mem. Geol.
Surv. Ind. vol. xv. (1880) pi. ii. fig. 2, shows the character of the deposit very
well, and may be contrasted with the photographic views in Mr. Wick ham
King's paper "(' Midland Naturalist,' 1893). The Talohir boulders are by no
means universally so well rounded as in Mr. Griesbuch s sketch, and in the
marine boulder-beds of North- western India the included fragment* are generally
angular.
Digitized by Google
Vol. 50.]
PERMIAN DRCCCIAS OF THE MIDLANDS
409
Carboniferous beds has been made very brief, as the facts have
already been published 1 ; but it is sufficient to indicate the grounds
on which a glacial origin is ascribed to tho beds. It is impossible
to bring any hand-specimens which will prove the case, for, as has
been remarked, they might individually be ascribed, with greater
or less plausibility, to other agencies. The most satisfactory proof, •
however, lies in the fact that all the observers who have studied
these deposits in the field, whatever may have been their preposses-
sions, have, without exception, come away convinced that ice is the
only agent capable of producing the effects which they have seen.
The nature of the Indian beds is so different from that of tho
English Permian breccias, that it would seem at first sight as if the
establishment of the glacial origin of tho one has no bearing on the
possibility of the presence of glacial debris in the other ; and this
notion might appear to be confirmed by tho fact that the accepted age
of the Australian and Indian marine glacial bods and of the
Talchir group of the Indian Peninsula is Upper Carboniferous,
while the English beds are always called Permian. It must be
remembered, however, that the Upper Carboniferous of the former
is in reality uppermost Carboniferous, verging on the lower limit of
the Permo-Carbouiferous of llussia,8 while tho Permian of the
latter is lowermost Permian ; their ago, indeed, is so uncertain that
it seems not impossible that they should be regarded as uppermost
Carboniferous, and very probably contemporaneous with the Indian
beds.
If this be tho case, there would be a real connexion between the
two, in spite of their apparent differences. We have proof that at
the close of the Carboniferous period both India and Australia,
apparently also Africa, experienced a period of greater cold than
prevailed before or after : a period, in fact, aualogous to the
Pleistocene Glacial period of tho northern hemisphere. This
being so, it would not be very extraordinary if the effects wore felt
in England and allowed of the production of local glaciers, a portion
1 A complete bibliography of this subject would cover several pages. Tbe
chief general accounts are those of H. F. Blanford, Quart Journ. Geol. Soc.
toI. xxxi. (1875) pp. 519-540; R. D. Oldbatn, Journ. As. Soc. Bong, vol. hii.
pt. ii. (1884) pp. 187-198; Geol. Mag. 1880, pp. 293-300 ; and W. Waageu,
Jahrb. d. k.-k. geol. ReicbsansUlt, Wien, vol. xxxvii. (1887) pp. 143-192.
For India, the original recognition of tl» glacial origin of the boulder-bed is
to be found in the report on the Talchir coalfield by Messrs. W. T. and H. F.
Blanford and W. Theobald, Mem. Geol. Surv. Ind. vol. i. (1850) pt. i.
pp. 49-51. References to subsequent account* of these beds and of the nioro
markedly glacial ones of the W«wt and North-west of India will be found in the
papers already quoted and in the * Manual of the Geology of India,' 2nd ed.
1893.
For Australia, see R. D. Oldham, Records Geol. Surv. Ind. vol. xix. (1880)
pp. 39-47, and T. W. Edgworth David, Quart. Journ. Geol. Soc. vol. xlni.
(1887) pp. 190-195, and the general accounts already referred to.
1 For India, see W. Waagen, ' Palieont. Indica,' Salt Range Fossils, vol. iv.
(1891) pp. 140-156: in the tabular statement opposite p. 238, these beds are
placed at the base of tbe Permian aystem. For Australia, see R. Eiheridge, Prof.
Roy. Phys. Soc. Edin. vol. v. (1880) pp. 314-319, and 4 Monograph of the
Carboniferous and Fermo-C;irboniferou» Invertebruta of New South Wales,'
Mem. Geol. Surv. N.S.W., Sydney, 1891, p. 3.
Digitized by Google
470
MB. B. D. OLDHAM OX THB
[Aug. 1894,
of whoso moraine-material was preserved in the so-called Permiau
breccias of the Midlands.
In this way we come round again to a position not very much re-
moved from that of Mr. H. F. Blanford in 1875,1 holding that the
Permian breccias are the English equivalent of the Indian Talchir
group. Whether or not this correlation, or the glacial origin of some
of the material of the Permian breccias, be accepted, this much
will always remain, that Sir Andrew Kamsay's paper suggested a
correlation of the Indian Talchir group which has since been
remarkably confirmed by the paheontological evidence.
IV. Conclusion.
Before concluding this paper it may be well to summarize the
points contained in it, which are :
(1) That the Permian breccias of the Midlands are subaerially-
forraed stream-deposite.
(2) That the material of which they were formed, though
distinctly waterworn, has not travelled tar.
(3) That the striations on the included fragments were, for the
most part, produced prior to deposition.
(4) That the striations are of a nature such as requires steady
movement under great pressure to account for them.
(5) That the agent to which the production of these strise can
be ascribed with most probability is a glacier.
(6) That the character of the Indian and Australian deposits is
such that they can only be ascribed to tho agency of floating ice.
(7) That the age of those deposits is probably the same as that
of the English so-called * Permian ' breccias.
(8) That the proved existence of a period of exceptional cold in
India and Australia makes it less unlikely that glaciers may have
existed at the same time in England.
The first six of these are independent of each other, and the
acceptance or rejection of one will in no way affect the rest. The
last two are more or less interdependent, and are at present as
incapable of proof as of disproof.
Discussion.
Prof. Lapwobth said that he had listened to Mr. Oldham's paper
with especial pleasure, for the subject of the origin of these Permian
breccias was one of extreme interest to Midland geologists, somo of
whom had already made known their general conclusions in various
communications at meetings of tho British Association and else-
where. The detailed proofs of their conclusions would, he believed,
be given in Mr. King's forthcoming paper, to which Mr. Oldham had
alluded.
The Midland geologists had long since found it impossible
to uphold the original view of Sir Andrew Ramsay that the
1 Quart Journ. Geol. Soc. vol. xxxi.
Digitized by Google
Vol. 50.]
FF.RMIAN BRECCIAS OF TEE MIDLANDS.
471
materials of these Permian breccias had been brought from the
Longmynd and Caradoc regions by floating ice. They believed
that the facts ascertainable in the field indicated, on the other
hand, the general correctness of the view of Phillips and Jukes
that these fragments were derived from ancient Midland rock-
ridges, subsequently partly removed by erosion, and partly buried
up by overlying geological formations. But it had also been dis-
covered that the recognizable materials in the different patches of
breccia are so restricted in their local distribution that they do not
seem to necessitate the hypothesis of a Permian Glacial period for
their formation ; and the Midland geologists have been content
rather to regard them all as original or rearranged subaerial
deposits, like those described by Dr. W. T. Blanford and others as
occurring in Central Persia and elsewhere, and to interpret them as
phenomena of . one of the natural phases in the general Continental
conditions indicated by the Permo-Triassic debits of Britain as a
whole. It was very gratifying to learn that Mr. Oldham, who was
so familiar with deposits of this character abroad, agreed generally
with the Midland geologists in their interpretation of these facts,
and as to the probable local origin of the materials of the breccias.
The Midland geologists, however, having relinquished the genoral
theory of the derivation of the materials of the breccias from a
distance, and well aware of the fact that some of the patches show
evidences of local dislocation, had been afraid to place much reliance
upon the evidences of markings and scratches upon the fragments
themselves ; and Mr. Oldham's paper would do good in calling the
very careful attention of local geologists to these curious phenomena.
It was by no means impossible that some of the Midland ridges,
whence these fragments were derived, were of great height in
Permian time, and may, indeed, have nourished small glaciers.
As respects the Lower Qondwana series, which had been paralleled
with these Midland deposits, he thought that the original suggestion
of Mr. Drew that deposits of such enormous thickness indicated the
simultaneous existence of mountain-chains in their immediate
neighbourhood, and consequently the existence of local glaciers, was
worthy of careful consideration. But it was extremely significant to
find that Mr. Oldham, who had personally studied these Permian
strata in India and Australia as well as in Britain, was so com-
pletely in accord with those who held that they gave evidence of a
Permian Glacial period ; and he could assure the Author of a
hearty reception from Midland geologists, should he find it advisable
to continue his researches among the striated stones of the Midland
breccias.
The Author, in reply, said that he recognized the existence of
scratchings due to earth-movements, but that apart from these there
appeared to be others to which this explanation was inapplicable.
His principal object had been to point out the great difference
between the Permian breccias of the Midlands and the Upper
Carboniforous glacial deposits of India and Australia.
Digitized by Google
472 MR. CHA8. DAVISON ON SNOWDRIFT DEPOSITS. [Aug. 1 894,
31. On Deposits from Snowdrift, with especial Refekence to the
Origin of the Loess and the Preservation of Mammoth-
remains. By Charles Davison, Esq., M.A., F.G.S., of King
Edward's High School, Birmingham. (Head June 20th, 1894.)
Coktbkts. Page
I. Introduction 472
II. Bibliography 472
III. Observations on Snowdrift Deposit* 473
IV. Formation of Snowdrift Deposits 475
V. .Nature of Snowdrift Deposits 432
VI. The Origin of the Loess 434
VII. The Preservation of Mammoth-remains 485
VIII. Origin of the Underground lce-formalion 485
I. Introduction.
The principal object of this paper is to draw attention to the occur-
rence of deposits from snowdrift, and to describe their nature and
the conditions under which they are formed. The subject is a wide
one, but in discussing it I have endeavoured to keep constantly in
view its bearings on two geological problems, about which there has
been, and still is, a considerable difference of opinion. These are
the origin of the loess, and the destruction of the mammoth and
preservation of its remains. The formatiou of underground-ice,
observed by Dall and others on the northern coasts of America and
Asia, will also be referred to.
When snow is driven by a strong wind, it is accompanied under
certain conditions by a considerable quantity of dust. The snow
and dust are deposited together in sheltered places, and, as the
former disappears by melting and evaporation, the dust is left on
its surface as a layer of mud, continually increasing in thickness as
the snow wastes away. The views here advanced are, briefly,
(1) that the loess is such a deposit from snowdrift, chiefly collected
when the climate was much colder, but still very slowly growing ;
and (2) that the mammoth was frozen or suffocated in masses of
drift-snow, and subsequently covered by the deposits formed from
them, which in certain cases attained a thickness sufficient to prevent
further melting of the snow beneath.
II. Bibliography.
Andrke.— ' Sur la Chasse-neige dans les Regions arctiques/ Arch, des Sc. phys.
et nat vol. xv. (1886) pp. 523-533.
Bkechky, Capt. F. W. Narrative of a Voyage to the Pacific and Beering'a
Strait.' 2 vols.. 1831.
Belcher, Sir E.— • The Last of the Arctic Vovages.' 2 vols., 1855.
Dall, W. H.— •Notes on Alaska and the Vicinity of Bering Strait,' Amer.
Journ. Sci. ser. 3, vol. xxi. (1881; pp. 104-111.
Dall. W. H., and O. D. Harris.—' Correlation Papers -Neocene,' U. S. Geol.
Surv., Bull. no. 84 (1802), pp. 260-08.
Db Lose, G. W.— ' The Vovage of the Jeannette.' 2 vols., 1SS3.
Gilder, W. H.— 'Ice-Pack and Tundra.'
Digitized by Google
Vol. 50.]
MR. CHAS. DAVISON ON SNOWDRIFT DEPOSITS.
473
Greely, A. W. — ' Three Years of Arctic Service.' 2 vole., 1886.
Hayes, 1. 1.—' The Open Polar Sea.' 1867.
Hoorer, J. D. — 'Himalayan Journals.' 2 vols., 1854.
Kk5dau Lieut. — * Account of the Island of Deception,' Roy. Geogr. Soe. Journ.
vol. i. (1832) p. 64.
Koldewey, Capt.. assisted l»v members of the scientific s'aff.— 'The German
Arctic Expedition of 1869-70.' Abridged translation, 1872.
I.anroeix, H.— * Through Siberia.' 2 vols., 1882.
M'Clistock, Sir Leopold.— ' The Voyage of the Fox in the Arctic Seas.'
I860.
M'Cu be, Capt. R. — * The Discovery of the North-west Passage by II.M.S.
Invest iqatt/r,' edited by Capt. Sherard Oshorn. 2nd ed. 1857.
MaRkuam, Capt. A. H. — * The Great Frozen Sea.' 1*878.
Hares. Capt. Sir G. S.— • Narrative of a Voyage to the Polar Sea.' 2 vols.,
1878.
NoanEXSRioLn, Baron A. E.— ' The Voyage of the Vega,' transi. by Alex.
Leslie. 2 vols., 1^81.
Parky, Capt. W. E. (A).—1 Journal of a Voyage for the Discovery of a North-
west Passage.' 1821.
Parky, Capt. W. E. (/?).—* Journal of a Second Voyage for the Discovery of a
North-west Passage.' 1824.
Parry, Capt. W. E. (C).—' Journal of a Third Voyage for the Discovery of
a North-west Pnssage.' 1826.
Payer, Jui.irs. — ' New Lands within the Arctic Circle.' 2 vols., 1870.
Rab, J.— "Major Greely on Ice," 'Nature,' vol. xxxiii. (Jan. 14th, 1896)
pp. 244-15.
Richardson, Sir J. — ' Arctic Searching Expedition.' 2 vols., 1851.
Ross, Sir John.— ' Narrative of a Second Voyage in search of a North-west
Passage.' 1835.
Scorbsby, W., Jun.— ' An Account of the Arctic Regions.' 2 vols., 1820.
Sf.rboiim, H. — ' Siberia in Asia.' 1882.
Wiiymper, E.— ' Scramble* amongtt the Alp*.' 2nd ed., 1871.
Wrasoei.l, F. von.— 'Narrative of an Expedition 10 the Polar Sea,' edited
by Sir E. Sabine. 184U.
III. Obsebvatiofs on Snowdrift Deposits.
1. Snowdrift Deposits in England.
I will first give a few brief descriptions of deposits from snow-
drift observed by myself in this country.
Cambridge: January 18<A, 1881. — The area affected by the great
storm of this date 1 included the whole of Wales, and all England
south of a line joining the mouth of the Mersey to a little north of
Flamborough Head. The snow was extremely fine and dry, and
penetrated in large quantities through cracks in windows and doors.
Its depth was greatest in the South of England, where in places the
total fall was as much as 2 feet. The storm was accompanied hy
an easterly gale of great violence. On one estate alone more than
1500 trees were blown down. Considerable snowdrifts were formed,
especially in railway-cuttings, where they occasionally reached a
depth of 20 feet. On the Great Western Railway, 51 passenger
trains and 13 goods trains were snowed up. At Cambridge the
storm, though violent, was lees severe The average depth of snow-
fall in the district was from 6 to 8 inches, and the drifts were
1 Symons's Monthly Met. Mag. 1881, pp. 2-24, 42-45.
Digitized by Google
474 MR. CIIAB. DAVISON ON SNOWDRIFT DEPOSITS. [Aug. 1 894,
generally from 3 to 4 feet deep. As the snow melted, it became
very dirty, and, when it disappeared, a thick coating of mud
was left on the ground, especially where the heaviest drifts had
collected. Along a road near Cambridge running N.E. and S.W., the
deposit close to the hedge was as much as ^ inch in thickness. It
was thiune9t in roads whose direction was at right angles to this.
Birmingham: March Iw, .1886. — Tho storm was most violent
in the North of England and in the South of Scotland,1 but in
Birmingham the snow had drifted so thickly that the tram-car
service was stopped. For several days previously there had been a
hard frost which lasted without intermission during the daytime.
On February 28th, the roads were dusty, the iuterstitial ice in the
frozen ground having evaporated. The snow consisted of exceedingly
fine ice-needles, which readily found their way through crevices in
window-frames. The drifts were from 12 to 18 inches deep, and
in places the surface of the snow had a dusky hue. By March 18th
most of the snow had disappeared. Nearly all that remained was
extremely dirty, and where there was none left the grass was
covered with a thin layer of mud about £ inch thick.
Birmingham: February \9th-20th, 181)2.— Snow began to fall a
few days before this date, and continued until the 19th. As a rulo
the temperature was several degrees below freezing-point, and the
flakes were nearly always very small. On the ground the snow
was fine and powdery, the total depth in spots where it had not
drifted being about 2 inches. On February 10th -20th the wind was
strong, the snow was raised in clouds, and from the roofs of houses
was whirled up in columns and eddies. On the morning of the
21st some rain fell.
In a narrow lane running N.W. and S.E. and a short distance to
the south of Birmingham, a good deal of drift-snow had collected.
It was banked up against the hedge on the north-eaatern side of tho
road to a height of 2£ or 3 feet, and a breadth of 3 or 4 yards.
The surface was, as usual, irregular, and for some distance distinctly
dirty or mud-coloured, especially in the hollows of the drift. The
snow was slightly dirty for a depth of 4 inches, the finer particles
of the mud having been washed down by the rain that fell in the
morning, but below this the snow was perfectly clean. Two days
later, on February 23rd, the snow was much reduced and dirtier, in
many parts tho surface was covered with a thin layer of mud, and
the whole of the snow down to the ground was discoloured. In one
part the dirt lay in streaks at right angles to the road, and these
streaks occupied slight depressions in the surface, due probably to
more rapid melting. As tho snow slowly disappeared, it became
granular in texture, and the layer of mud on the surface increased
in thickness, especially along edges or angles of hollows in the drift.
The ultimate thickness of tho deposit was about ^ or yV inch
on an average, but in places it was fully \ inch. When rubbed
between tho fingers, the dust felt smooth, almost like flour, though
particles of larger size were distinctly visible.
1 Symona's Monthly Met. Mag. 1886, pp. 17-21, 33-56.
Digitized by Google
Vol. so.]
ilR. CHA8. DAVISON ON SNOWDRIFT DEPOSITS.
475
2. Snowdrift Deposits in the Arctic Regions.
In the Arctic regions the conditions are exceptionally favourable for
the formation of deposits from snowdrift. The deposits are hardly
likely, however, to attract the close attention of travellers, though
incidentally the conditions are somewhat fully described in their
narratives. One reason, no doubt, for the absence of notices is that,
however thick the deposits may be, everything below the first foot
or so is perpetually frozen and beyond the range of casual observa-
tion. But, just as in this country the last surviving patches of
snowdrift are always more or less discoloured, so Arctic travellers
Bometimes refer to the black and dirty snow to be found in spring
at the foot of cliffs. According to M'Clure, decaying ice and snow
are of a dingy yellowish hue. Parry remarks that a fall of fresh
snow in the summer months gives a more wintry aspect to the
scenery than the untnelted snow of the preceding winter. This, he
says, is u always easily known by its dingy colour, and its admixture
with the soil." The last observation is an important one, and it
also explains how snowdrift deposits may be overlooked. The sur-
face of snow- and ice-fields is occasionally darkened by dust,
evidently wind-drifted, and dirt-layers are seen in the interior wheu
the edges of tilted floes aro exposed or when excavations are made
in the suow.1
The most direct evidence on this point is that given by the lato
Dr. J. Kae, who spent several winters in the north of Canada. " In
all parts of Arctic America where I have been," he says, ** a fall of
snow is usually either accompanied or followed by a gale of wind
more or less strong, chiefly from one direction, with thick snowdrift,
which cuts away earth and sand in minute particles from the wind-
ward side of any hill or rising ground in its course, and these
particles are carried along until they find a resting-place under the
lee of some steep bank or cliff. These foreign substances, when
mixed with a gTeat depth of snow, aro not readily seen, but when
the spring evaporation and thaws remove a great part of the snow,
a stratum — more or less thin — of coloured matter, is visible on the
surface." 3 It will be seen from the next section that several of the
conditions under which snowdrift deposits are formed are clearly
described in this passage.
IV. Formation of Snowdrift Deposits.
1. Formation of Snowdrifts.
Snow falls in the form of flakes only when the temperature is
not far from the freezing-point. In high latitudes, especially in
winter, flakes are unknown, and the snow consists of tine, hard
1 (The index to the abbreviated references in this and the following footnotes
will be found on pp. 472-473.)- Greely. vol. i. pp. 312, 398-99, vol. ii. pp. 30-31 ;
Koldewev. p. 120; MCliutock, p. 14C> ; M'Clure, pp. 11)3, 221); Kare«, vol. i.
pp. 149, lfi8-69, vol. ii. pp. 12. 59, «1 ; 'Nature,' vol. xxni. (March 22ud, 1883)
p. 496, vol. xxix. (Dec. Otb, 1883) p. 135 ; Nordenskiold, vol. i. p. 178; Parry C,
pp 23. 104, 155.
* "Major Oreely on Ice," 'Nature/ vol. xxxiii. (Jan. 14th, 1880) pp. 244-45.
Digitized by Google
476 MR. CHAS. DAVISON ON SNOWDRIFT DEPOSITS. [Aug. 1 894,
ice-needles, so minute that they pass easily through the smallest
crevice in doors or windows. At times, countless ice-needles fill
the air nnd make a continual rustling noise ; distant objects appear
covered with a thick veil or clothed in a dense mist, and the clear-
ness of day is reduced to a dull yellow twilight.1 But even when
the sky seems perfectly clear, these fine crystals hardly ever cease
from falling ; any object left exposed is soon coated by them, and
even the bare patches on hill-tops become gradually whitened by
this invisible precipitation.3
Fine snow like this lies upon the ground loose as dust or powder,
and, until it is closely packed by the wind or encrusted by the
action of the sun, it is drifted with the greatest ense. The least
puff of wind sets it in motion, and snow-banks are piled up wherever
an obstruction is encountered.3 At Pitlekaj, in Northern Siberia, a
shallow, but rapid and uninterrupted stream of snow was observed
by Nordenskiold, and he estimated that the quantity of water thus
driven in a frown form must be equal to " the mass of water in the
giunt rivers of our globe." *
But, important as is the work performed during this incessant
drifting, it is not to be compared with that of the violent gales and
storms of Arctic lands. There, from the summits of hills and from
exposed places, the snow is torn off in sheets by the fierce gusts of
wiud. In eddying columns it is whirled upwards for hundreds of
feet, or driven away in wreaths as if the hill-tops were smoking.
Great clouds of snow sweep down the slopes and rush over the cliffs
in strange fantastic forms. Down below, on the more level ground,
the whole air is filled with flying, streaming snow, which no human
being can face, and none can endure for many hours. Objects a
few yards off are completely hidden from view, and soon every
landmark is obliterated.* Such storms may last for days, and when
they are spent the crests of the hills are seen to be bared, the valleys
and ravines are choked with light soft snow, and under the shelter
of cliffs there collect great snow-slopes which often outlast the
succeeding summer.6
1 Belcher, vol. i. pp. 318, 358 ; De Long, vol. i. pp. 147-48 ; Greyly, rol. i.
p. 183; Hayes, p. 194 ; Koldcwey. p. 4*22 ; Markham, p. 161; Nares, vol. i.
p. 319 ; Nordenskiold, vol. i. p.*517 ; Parry C, p. 77 ; Payer, vol. ii. pp. 50,
61 ; Richardson, vol. ii. p. 98.
2 Hayes, p. 218; Nares, vol. i. pp. 240-47; Parry B, pp. 153. 420; Parrv
C, p. 77 ; Payer, vol. i. pp. 244, 299. 300.
3 Belcher/vol. ii. p. &r> ; Nares, vol. i. p. 146 ; Nordenskiold, vol. i. p. 473 ;
Parrv B. pp. 129. 139, 189, £00.
* Nordenskiold, vol. i. pp. 483-84 ; Andree. pp. 523-33.
s De Long, vol. i. pp. 147-48, 258. 34-M : Gilder, pp. 1 18-19. 164-66 ; Haves,
pp. 189-91, 302; Koldewey, pp. 125. 383-84, 399, 422; Lansdell, vol." ii.
pp 563, 635 ; M'Clintock. pp. 60, 95 ; M'Clure, pp. 237-38 ; Markham, pp. 161,
169-70; Nares, vol. i. pp. 142, 163 ; 'Nature,' vol. xi. (Feb. 25th, 1875) p. 334 ;
Nordenakiold, vol. i. p. 483; Parry A, pp. 109-10, 156-57, 179; Parry 2?,
pp. 150,190; Wrangell, p. 194.
• For references to snow-elopes under cliffs, see Beechey, vol. i., pi. facing
p. 311 ; Belcher, vol. i. p. 272 (also pi. facing p. 271); Grimly, vol. 1. p. 312 ;
Narea. vol. i. pp. 241. 286. 290, 316. vol. ii. pp. 79. 90-92 : • Nature,* vol. xxxiii.
(Jan. 14th, 1886) p. 244; Richardson, vol. i. pp. 279, 283-84.
Digitized by Google
Vol. 50.]
Ml!. CHAS. DAVISON ON SNOWDRIFT DKPOSITH.
477
The amount of snow that settles in valleys and ravines, especi-
ally in those whose direction is at right angles to that of the pre-
vailing wind, must be very considerable. 1 have not succeeded in
rinding any reliable estimates. The common expression that after
a storm the ravines are filled with dritt-snow cannot be taken to
mean much. At the foot of a mountain in Grinnell Land, (ireoly
met with a line of almost vertical snow-banks and drifts, the front
of which ranged from 100 to 150 feet in height.1 This is probably
an unusual amount, and it may have been the accumulation of
many seasons. But if we remember that 10 or 15 feet is not nn
excessive depth to collect in railway-cuttings during one of our
severer English storms, and then compare the latter with the far
more violent and more frequent Arctic gales, we shall be prepured
to accept a high estimate. On the other hand, the total snowfall
in Arctic regions is by no moans great, but the snow is much
denser than that which falls in warmer climates. The average
weight of a cubic foot of snow at Port Bowen was found by Rowland
to be ^0 pounds.*
The time of year at which snowdrifting is most frequent and
considerable is a subject on which information is still required.1
In Russia, where snowdrifts seriously disturb the railway-system,
Air. Srcsnewskij has made some interesting enquiries. He finds
that the drifting is at a maximum in mid-winter, but there is more
in the second ^half of winter than in the first, there being then more
snow to drift. There are also most drifts in the months when the
snowfall is least and in which there are fewest days of Bnow.1
2. Origin and Transportal of the Dust.
In Arctic countries, hills and exposed places are soon denuded of
their snow, a few hours being sufficient for a strong wind to remove
the fall of many days. Even when the snow has become so packed
as to provide blocks for snow-buildings, it can in these situations
otter no permanent resistance to a violent wind. Plains are some-
times cleared so that sledging is impossible/ It is from such
places bared of snow that the material of snowdrift deposits is
derived. The hard frozen ground may be converted into dust in
two ways: (l)by evaporation of the interstitial ice, and (2), as
1 Greely, vol. i. pp. 402-3 ; Nares, vol. i. pp. 323-24. As snow in large
masses is granulated at a small depth, may uot oxten.-ive accumulation* of
drift- snow bo sometimes confused with snow-covered glaciers ? On this point
sec Hooker, vol. ii. pp. 90, 110; Nares, vol. ii. pp. 17-18, 79-80.
a Parry 6', p. 77, footnote.
3 It can hardly be determined from the casual records in Arctic narratives,
for the drifts would naturally attract more attention in the sledging season.
* ' Nature,' vol. xliv. (Aug. 20th, 1801) p. 380.
s Belcher, vol. i. pp. 15<i, 101, 238, 318; Greely, vol. i. p. 183; Lansdell,
vol. i. p. 228 (footnote) ; M'Clintoek, pp. 210-11 ; Murkhaui, pp. 153-54; >ares,
vol. i. pp. 103-04, 188 ; Parry A, p. 100 ; Ross, pp. 171, 177, 208, 018; Wran-
gell, pp. 30, 270.
a J. G. S. No. 199. 2 k
Digitized by Google
478 MB. CBAB. DATIBON OK SK0WDBIFT DEPOSITS. [Aug. 1 894,
Dr. Rae suggests, by the friction of hard particles of wind-driven
6dow. Of these, the first is probably by far the more efficient.
Dust due to Evaporation of Interstitial Ice. — Evaporation takes
place from ice and snow at the lowest temperatures experienced
in high latitudes. " When a shirt, after being washed," says
Richardson, " is exposed in the open air to a temperature of 40° or
50° below zero, it is instantly rigidly frozen In an hour or
t wo, however, or nearly as quickly as it would do if exposed to the
sun in the moist climate of England, it dries and becomes limber."
The joints in houses built of ice-blocks are gradually enlarged by
evaporation, so that drift-snow can enter ; and a freely-suspended
cube of ice, according to Payer, lost one-hundredth of its weight
daily from the same cause during the latter half of March.1 It is
important to notice that the evaporation occurs without any ap-
parent wetting of the surface on which the snow or ice has been
resting a ; so that, when the interstitial ice of frozen soil evai>orates,
the surface is left dry and dusty. In England I have frequently
noticed that the roads become dusty after a few days of dry frosty
weather" ; and the same phenomenon has been observed by Sir (i.
Nares, but to a far greater extent, in lat. 82' 26' X. " Along the
borders of the old lake-bottoms," he remarks (on May 7th, 1876),
*' the mud, which was frozen as hard as any rock during the winter,
is now pulverized ; where a month ago it was difficult to dig out stones
and shells with a metal instrument, a stick or the finger can now
e;isily be forced an inch deep into the softened earth ; this must be
entirely due to evaporation." And again (Aug. lath) he writes
44 At this season the ground was evidently hardening for the winter.
During the spring, long before the temperature of the air was above
freezing-point, the earth became pulverized to the depth of two or
three inches, all the moisture which had rendered it hard through-
out the winter having evaporated. During the latter part of the
summer the moisture again collects as dew and the earth hardens
completely." * While dust must be formed in this way, though in
small quantity, all through the winter, it will be noticed that it is
greatest in amount at a tiino of year when enowdrifting is of fre-
quent occurrence.
Diutt due to Friction of Hard Particles of Wind-driven Snow. —
At very low temperatures the fine grains of snow become intensely
hard. If rubbed upon the face in cases of frost-bite, they cut
through the skin. Sledges no longer glide, but drag heavily as if
over a surface of sand or sandstone, unless the runners are wet and
bo coated with a thin layer of ice. When driven by the wind
these hard particles act as a sand-blast, wearing down blocks of
bijow and ice ; and, in a passage already quoted, Rae states that
' Hayes, pp. 218-19; Nordenskiold, vol. t. p. f>09; Payer, vol. i. pp. 244,
258, 270, vol. ii p. 114; Richardson, vol. ii. p. 100.
2 Hooker, vol. i. p. 243 ; Nares, vol. i. pp. 272, 276, 311-12, 318.
3 I may add that I have never observed any deposits from snowdrift when,
the weather preceding the fall of snow was comparatively mild and dump.
« Nare?, vol. i. pp. 315-lli, vol. ii. pp. 134-30.
Digitized by Google
Vol. 50.]
MR. CHA3. DAVISON OS SNOWDRIFT DEPOSITS.
479
they cut away earth and sand in minute particles from the wiud-
ward side of any hill or rising ground in their course.1
Transportal of the Dust. — In whichever way the dust is derived,
it will be driven with or after the snow and deposited in the same
places, cither mixed with or covering the drifts. That it should
ever be noticed in the act of drifting with the snow is improbable,
considering its extreme fineness. Nares records, however, " a
blinding snowdrift mixed with sand and small pebbles which were
carried by the fury of the storm." Snow and sand are sometimes
driven in the faces of travellers as they walk, so that they can
scarcely keep their eyes open. During his journey along the Lower
Aniuj River, in North Siberia, von Matuischkin made a similar
observation. "The death-like stillness which prevailed," he says,
was "suddenly broken by violent guste of wind, howling and
sweeping through the ravines, and whirling up high columns of
snow and sand."3
Long after all the snow has been blown away from exposed places
dust may continue to be conveyed by tho wind to the surface of
snowdrifts. ** In consequence of the bareness of the land from
snow," Nares remarks on Sept. 19th, 1875, u the dust has been carried
off by the wind, and has discoloured all the floebcrgs. This evidently
accounts for the dust sediment left at the bottom of tho water pools
on the surface of the floes, and for that frozen deeply into the ice "
(vol. i. p. 145)). Nor are dust-storms unknown in Arctic regions, one
that occurred on July 9th, 18S2,3 being recorded by Oreely. It is
evident that some of the dust transported in this way may
ultimately form a part of deposits from snowdrift.
3. Hardening of Snowdrifts.
So long as the snow remains loose and powdery on the surface,
snow-banks accumulated on open ground are continually shifting
like sand-dunes, and drifts in many places are liable to removal
with a change of wind. * Under these conditions, deposits from
snowdrift would not have a much greater prospect of preservation
than any ordinary, unprotected, seolian formation, unless they occur
in very sheltered valleys and ravines. Generally, however, the
snow, by superficial melting and re-freezing, is soon encrusted with
a layer of ice, or it is closely packed by the action of the wind. The
dust is thus imprisoned in the hardened Bnow, and the deposit from it
tends to become a permanent addition to the products of former
years.
Snow hardened by the Action of tlie Sun. — Long before the tempe-
rature of the air reaches the freezing-point, tho sun has sufficient
1 Do Long, vol. i. pp. 299^367, vol. ii. p. 517; Groely, vol. i. pp. 211, 224 ;
Haye*. p. 285; M'CHntock, pp. 210-11 ; « Nature,' vol. xxxiii. (Jan. 14th, 188(f)
pp.* 244-45; Nordenskiold, vol. ii. p. 103; Payer, vol. i. p. 254, vol. ii. pp. 11,
62-5 *, 114 ; Wrangell, pp. 102-3, 104.
a Koldewey, p. 422 ; Markhain, p. 154 ; Nares, vol. i. p. 142 ; Wrangell,
p. 104.
1 Greely, vol. i. p. 410. * Nare*, v0L i. pp. 273-74.
2 k 2
Digitized by Google
430 M*. CHAS. DAVISON ON SNOWDRIFT DEPOSITS. [Aug. 1894,
power at mid-day to affect the snow. The surface is thus made
soft and sticky, and, during the frost which follows, every crystal
receives a thiu coating of ice and the snow becomes granular in
texture, the optical axes of the grains being of course disposed in
every possible direction. As the grains increase in size, the inter-
vening air-spaces are more or less filled up, and the surface of the
snow is glazed and soon coated with a crust of ice. In the Lower
Kolyma district (Siberia) this state of the snow, according to
Wrangell, is called * Nast.' " The hunters profit by it to pursue the
elks and reindeers by night ; and as the weight of these animals
causes them to break through, they fall an easy prey/'1 Thaw-
water from the surface, however, continues to filter through the
capillary passages in the crust, and, meeting with the colder snow
below, is again frozen, the whole mass thus becoming granular.
" Early in the spring," says Nares, " wherever the stratification of
the snow covering a floe had become exposed at a newly-formed
crack, the lower portion of the snow was observed to have granulated,
the grains collecting together perpendicularly, the lower ones being
the largest and leaving intermediate air-spaces." According to obser-
vations made by Parr during Markham's northern sledge-journey in
1876, 44 the general depth of the snow was from two and a half to
three feet, the upper portion, underneath the surface crust, consisting
of loose grains of about the size of rifle fine-grain powder, and
without the least coherency ; these gradually increased in size, till
about two thirds of the way down they were as large as rifle large-
grain powder, but still separate. Below this, however, the grains
began to unite and to form very porous ice, till, at the actual point
of junction with the floe, it was very- difficult to draw the line of
demarcation. In all cases the ice on the surface of the floes had
evidently been formed in the same manner, for it was full of air-
holes, though not nearly to so great an extent as that which was in
process of formation. ... In one case, also, we found a section of
a drift seven feet thick at the highost point, which was divided into
three equal parts by two layers of ice half an inch thick ; the lower
portion being nearly converted into ice, the middle not to such an
extent, while the upper had only just commenced." 3 If, then, the
melting take place slowly, masses of snow are in time converted
into ice identical, except perhaps in the absence of marked fluxion-
structuro, with that formed in glaciers.3
Snow hardened by the Action of the Wind. — As already remarked,
snow at low temperatures is dry and loose. In ravines and under
cliffs, where the snow is sheltered from the wind, it remains iu this
condition, until the sun has power to glaze or melt it. But if exposed
1 Wrangell, p. 61 (footnote).
a Nares, vol. ii. pp. 63-64, 69.
» Andree, p. 524 ; Nares, vol. i. pp. 279, 301, 367-68 ; Nordenstiold, vol. i.
pp. 136-37 ; Parry B, p. 114 ; Richardson, vol. ii. pp. 99-100; Rosa. pp. 163,
f»10; Scoresby, toI. i. p. 34; Wrangell. p. fil (footnote); Whymper. pp. 426-
31. See nlso an admirable pnper by F. A. Forel, • Le Grain du Glacier, Arch,
dea Sc. pbya. et nat., vol. vii. (1882) pp. 329^375.
Digitized by Google
Vol. 50.] MB. CHA8. DAVISON ON SNOWDRIFT DEPOSITS. 481
to the wind it is packed and hardened, and until this happens
snow cannot bo used for building, and sledging is difficult and
often impossible. ** Fortunately for the architects," says Nares,
** the gales in the middle of September had formed hard snow-
banks, out of which a compact building-material was readily pro-
cured." " The snow, in spite of the low temperature," says Payer
(Oct. 25th, 1872), ** lay in such masses between the small hummocks
and ou the few level places that they [the sledges] sank deep into
it. It is storms of wind only that harden the snow, and for some
time we have had calms or light breezes." " Yesterday's storm,"
remarks Greely (Jan. 17th, 1882), "has stripped every exposed
place of its usual snow, to pack it in dense, hard drifts, in the
hollows of the ground." 1 So far as I am aware, no explanation has
been given of the action of the wind in hardening snow at a low
temperature ; but that it has such an effect is clear from numerous
observations, and from the importance attached to it by Arctic
travellers.
4. Disappearance of Snow by Melting and Evaporation.
During the Arctic winter snow and ice undergo but little decay,
for evaporation then takes place slowly, and it is not until late in
the spring that the sun can effectually melt the snow. The sun
alone has but little thawing power, until it has attained a consider-
able altitude. It is aided greatly, however, by the presence in the
snow of dust, sand, and minute plants, and when the dark earth or
rock below becomes partially uncovered, or when the snowdrift
deposit begins to appear on the surface, the rate of decay is materi-
ally hastened. Showers of rain, and dry warm winds of a fohn-
like nature, also assist largely in the disappearance of snow.a
Isolated stones and small patches of earth, owing to their power
of absorbing heat, sink some distance into snow ; kryokonite, as is
well known, is found at the bottom of holes in the Greenland ice.
But a thin and continuous coating of earth, liko that which covers
many decaying snowdrifts, practically remains upon the surface,
though the finer particles may be washed down by rain and thaw-
water, to discolour the snow-granules below. So long as it remains
thin, this coating helps to melt the subjacent snow, and it increases
in thickness by tho continual addition of particles to its under-
surface. But a limit may at last be reached, depending chiefly on
the depth to which tho summer-heat penetrates the ground, when
the deposit on the surface becomes thick enough to prevent further
melting of the snow until a warmer climate supervenes.
1 Greely, vol. i. pp. 183, 224 ; Hayea, pp. 217-18 ; Koldewey, pp. 370-77 ;
M'Clintock, pp. 207, 301 ; Harkliam, p. 344 ; Nares, vol. i. pp. 177, 100-91,
222, 292; Payer, vol. i. pp. 178-79, 229, vol. ii. p. 39 ; Richardson, vol. i. p. 349.
a Belcher, vol. i. p. 312 ; Hooker, vol. i. p. 252 ; Mnrkhaui, pp. 380-83 ;
Karea, vol. i. pp. 40, 310-11, vol ii. pp. 3, 6-7 ; Nordenakiold, vol. ii. pp. 33-35;
Parry A, pp. 165-00, 176; Parry B, p. 114 ; Payer, vol. ii. p. 252; Seebohm,
p. 101.
Digitized by Google
482 MR. CHAB. DAVISON OK SNOWDRIFT DBP0SIT8. [Aug. 1894,
Y. Nature of Snowdrift Deposits.
1 . Fineness of Texture.
One of the most noticeable features about the snowdrift deposits
that I have had an opportunity of examining is their oxtremely fine
texture. When rubbed between the fingers, the material generally
feels smooth like flour. If it be put in water and disturbed, part sinks
within a few minutes, but the water remains discoloured for several
days. No doubt a strong wind is capable of driving, and does drive
much larger particles ; instances have already been given of sand
drifted with snow. But such particles would not be carried far;
they would be easily dropped during brief lulls in the storm, and
perhaps dropped beyond recovery. The finer dust, however, re-
mains suspended in air for some time and may bo carried great
distances. Extensive and continuous deposits from snowdrift must
almost inevitably be flue-grained.
2. General Absence of Stratification.
"When the decay of snowdrifts takes place slowly, it seems almost
evident that the deposits from them must be unstratificd. For, as
each granule of snow melts, the fine dust-grains coating it subside
irregularly, and there is no force acting, as in currents of water, to
arrange them in any definite direction. Occasionally dust of larger
size from a nearer origin might be deposited in a snowdrift, or dust
of an entirely different nature, and these might form layers in the
future deposit. They might even give it an appearance of stratifi-
cation, the layers being roughly parallel to the original surface of
tho ground. But the snow in a drift lies so irregularly and is of
such varying depth, tho rate at which it decays depends so much on
the thickness of its coating of mud, and in this mud there may be
differential movements as it is gradually lowered by the decaying
of the snow below, that the probability of any final appearance of
stratification is rather remote. If continuous layers were, however,
formed, they would most likely be of a wavy and irregular
character.
In connexion with this absence of stratification, I made several
experiments during the winter of 1891-92, one of which may now
be described. On a large piece of millboard, I placed (1) a layer of
clean snow, 25 inches long, 17 inches broad, and 6 inches thick ;
(2) above this a layer of snow mixed with fine dry soil, the snow
and soil being showered alternately until a layer 3 inches thick
of dirty snow was formed ; (3) on this a layer of clean snow 5 inches
thick ; (4) a layer, 1 1 inches thick, similar to the second, except
that the dust was previously mixed with mica-flakes, most of them
very small ; and (5) a top-covering of clean snow, 3 inches thick.
The appearance of the mound was carefully watched from day to
day. The uppermost layer of snow soon melted, and the usual
Digitized by Google
Vol. 50.] MR. C1I AS. DAVISON 05 SNOWDRIFT DEPOSITS. 483
covering of mud was formed on tho surface. After 18 days the
snow had entirely disappeared, and a deposit nearly an inch thick
was left behind. In this there was not the least sign to be detected
of any surface of separation between the mud from the secoud and
that from the fourth lnyers. The only trace of their original division
was the presence of the mica-flakes in tho upper part of the deposit.
This experiment is, I think, of some value, though not perhaps
decisive — on account of the small scale on which it was made. To
prove the general absence of stratification in snowdrift deposits, I
would rather trust to tho absence of any reason why stratification
should exist.
Arrangement of Mica-flakes in Snowdrift Deposits. — In the Chines©
loess, Richthofen has observed that mica-flakes arc arranged in-
discriminately and not horizontally, and it was on this account that
mica-flakes were mixed with the dust in the fourth layer of the
preceding experiment. The flakes were generally small, most of
them about -j-^ inch or slightly more in diameter, but some were
larger, and a few were about | inch long. While the snow was
melting, these flakes appeared in the mud extruded on the surface,
but there was no sign whatever of a horizontal disposition. When
the snow had completely disappeared, from the largest flake to the
smallest they were inclined at all angles to the horizon, and in
every direction.
Occasional Stratification in Snowdrift Deposits. — Pools of thaw-
water are sometimes formed on the surface of decaying snow ; streams
of melted snow may carry into them some of tho surface-mud, and
true aqueous deposits may thus be intercalated in the snowdrift
formation. These pools are no doubt caused in some cases by the
varying thickness of the incipient snowdrift deposit. " ltound a
ship which has wintered in the ice," says Payer, " t here is gradually
accumulated a mass of rubbish of all kinds, of which cinders form a
considerable constituent These, when thrown out in small quan-
tities, sink at once into the snow, while larger quantities act as a
non-conducting layer. Hence we were surrounded by a maze of
holes, big and little, alternating with plateaux, under which winter
still continued to linger. When thaw-water made its appearance,
all this was transformed into a succession of lakes and islands,
which we bridged over by planks." 1
During rapid thaws, the water rushes down valleys and ravines
in torrents, and mud and gravel are spread out in sheets over the
snow and ice at their mouths.51
But in both these cases, unless the deposits are laid down directly
on snowdrift formations having no thick layers of snow and ice
beneath them, the original stratification must be largely interfered
with by differential movements due to unequally rapid melting of
the snow below.
1 Paver, vol. i. p. 251.
3 Nojre*, vol. ii. pp. 12, 55-56, 65-66 ; Seoresby, vol. i. p. 476.
Digitized by Google
484 MR. CHAS. DAVISON OK SNOWDRIFT DEPOSITS. [Aug. 1894,
YI. The Origin op the Loess.
I propose now to refer as briefly as possible to the geological
problems mentioned at tho beginning of this paper.
The snowdrift theory of the loess is in great part described in the
preceding pages. During the Glacial period a large part of Europe
wus unoccupied by ico. In the districts adjoining the ice-sheet, a
similar though milder climate must have prevailed. The winters
must have been long and the summers comparatively short ; the
former being characterized by heavy storms, violent gales, and much
snowdrilting. Abundant dust-material would be provided by the pro-
ducts of glacial erosion. During the summer most of the snow, except
in sheltered places, would melt, and the Rnowdrift deposits would
be formed chiefly in tho valleys, more thinly on the higher ground and
plateaux. Thus, every years new layer would be added, each layer
merging imperceptibly into that of the previous season, the whole
covering high and low ground alike, except that it would attain a
greater thickness in the more sheltered places, and would be
altogether absent in exposed spots on hillsides and crests. With
the advent of a warmer climate and the retreat of the ice-sheet,
there would be a gradual expansion of the snowdrift formation,
overlapping the glacial deposits along their border, but diminishing
in thickness the more rapidly the ice withdrew.
In many respects the snowdrift theory bears a close resemblance
to the rcoli'an theory of Baron F. von Kichthofen. But they obviously
dilFer in sorao important points. I will now endeavour to show,
(i) that the snowdrift theory accounts for the more prominent
features of the loess, and (ii) that it escapes several of the objections
which have been urged so forcibly against the ffiolian theory.
The snowdrift theory seems to me to give a satisfactory explana-
tion of the following peculiarities of the loess, which distinguish it
so strongly from the other formations with which we are acquainted :
(1) its independence of altitude above the sea-level ; (2) its occur-
rence in uniform sheets over plains and table-lauds, and the concavity
of its surface when developed between two ridges ; (3) its homo-
geneous composition and structure; (4) tho complete absence
of stratification in pure loess, and the indiscriminate arrangement
of included mica-flakes ; (5) the occurrence of angular grains of
quartz ; ((») the inclusion of layers of angular fragments in loess
near hillsides; (7) the great quantity of bones of mammals (this
will be referred to in the next section) ; (8) the presence of land-
shells and the preservation of delicate shells ; and (J)) the peculiar
character of the fauna, resembling that of sub-Arctic steppes or
tundras.
I have not referred here to the calcareous concretions, the root-
like tubular structuro, or the tendency to vertical cleavage, all
characteristic features of the loess. The concretions are in all
probability a subsequent formation, and do not here require a
special notice. Jhe explanation of the others given by Kichthofen,
if it holds for the fieolian theory, will also probably* hold for the
snowdrift theory.
Digitized by Google
Vol. 50.]
MR. CHAS. DAVISON ON SNOWDRIFT DEPOSITS.
485
In the particulars mentioned above, the two theories agree very
closely. The first tive points and the eighth are explained equally
well by both ; but in the remainder the balance, I think, inclines
slightly in favour of the snowdrift theory.
I will now mention a few points in which the snowdrift theory
seems to me to have a decided advantage, in explaining objections
which it is more or less difficult to meet on the teolian theory.
( 1 ) It accounts more satisfactorily for the fixing of the dust -material :
first in snowdrifts hardened or packed by the action of sun and
wind, and afterwards in the frozen ground. (2) It agrees with
the geographical distribution of the loess, its occurrence as a fringe —
a partly overlapping fringe — to the glacial deposits. (3) It postulates
no change of climate or geographical conditions other than those
which nearly ail are agreed did obtain during the Glacial period ;
and it does not require the existence of a centr.il desiccated area.
Lastly, the snowdrift theory gives an explanation of other related
pheuomena, namely, the destruction of the mammoth and the pre-
servation of its remains, and the origin of the underground-ice
formation. In this it fulfils one of the most stringent tests of a
satisfactory theory.
VII. The Preservation op Mammoth-remains.
8everal writers have advanced the view that the mammoth met
with its fate during violent storms accompanied by intense cold
and blinding snowdrifts.1 In order to escape the violence of the
storm, animals would rush to the nearest woods (if they existed) or
to any sheltered place, the very spots where snowdrifts, owing to
the cessation of tho wind, would be most thickly collected. In these
drifta they would frequently be snowed up, or entrapped in their
effort* to escape when the storm was over. As the Bnow gradually
disappeared, the deposit from it would envolop the mammoths, and
thus their remains, if the climate continued cold, would be embedded
in frozen earth, containing perhaps layers of granular snow as hard
and firm as glacier-ice.
The abundance of remains in particular spots may be due partly
to the mammoths continually seeking the same places of shelter,
but chiefly, I think, to the earth being the comparatively thin
residual deposit from the masses of snow in which they were
entombed.
VIII. Origin op the Underoroitnd-Ice Formation.
Tho underground-ice formation, consisting of alternate layers of
ice and clay, has been described by Dall and other writers. Allu-
sions to layers of ice in the ground are also met with in tho
narratives of several travellers.2
1 Strong wind with snowdrift produces a feeling of suffocation, which ia not
experienced in wind without snowdrift ; see Koldewey, p. Slrt).
* W. II. Dall, pp. 104-111 ; W. II. Dall & G. D. Harris, pp. 260-08, with
references to other observations ; in addition to which see Lieut. Kendal, p. 04 ;
Digitized by Google
4S6 HB. CHAS. DAVISON ON SNOWDRIFT DBr08ITS. [Aug. 1 894,
In high latitudes, masses of drift-snow under favourable con-
ditions occasionally last through the summer. The deposit formed
on the surface by their partial decay serves as an additional protec-
tion,1 the snow that remains having been rendered granular by the
re-freezing of infiltrated thaw-water, and perhaps slightly
discoloured by the fine particles of dust curried down by it. If the
same process is repeated year after year, a mass of ice will be
formed, tho growths of successive seasons being separated by thin
layers of earth or clay. But, in all probability, this will not often
occur, and a year of abundant snowdrifting may be followed by
others in which the snow disappears more or less completely, and
the annual deposits practically coalesce. Now, in Arctic regions,
the summer thaw does not often penetrate beyond about a foot in
depth.9 If, then, the thickness of the deposit should ever exceed
this limit, it follows that the snow below will not melt so long as
the climate remains unchanged. In this way, alternate layers of
ice and clay may be built up, the ice corresponding to the snow of a
few unusually heavy drifts, the clay being the residual deposit from
several or many slighter ones. The remains of animals should thus
occur chiefly in the layers of clay ; but, if the theory be correct,
they should be found sometimes, though perhaps rarely, in the layers
of ice.
Discussion.
Prof. Blake asked what necessary connexion snow had with the
formation of loess. As far as he could see, the dust could be blown
about as well without it as with it, and the deposit might equally well
be formed in a tropical climate to-day as during the Glacial period.
Prof. Boyd Dawkins considered that the word ' loess ' was an un-
fortunate term. If the material were called * loam,' it would at
once be realized that loam may be either tho result of the wind or
of deposit by water, or the work of the earthworm. The mam-
moth had nothing to do with the question, because it occurred in
the South of Europe and in North America far away from the range
of the * loess.*
Mr. Oldham said that he happened to have a personal acquaint-
ance with the deposits left after the melting of snow and with the
loess. The former were found in sheltered spots on the ridges
of the Himalayas which are annually covered with snow, but (so far
as his experience went) they were denser and more compact than
the true loess ; they were in fact dried muds, while the true loess was
a dust. On the hills of the Western frontier of India, where loess
was largely developed and etill in course of formation, the distri-
bution, surface-contour, and constitution showed it to bo a wind-
M'Clintock, p. 146 ; Narea, toI. ii. pp. 12, 13, 47, 66 ; Nordenskiold, toI. i.
op. 378, 436 (footnote), vol. ii. p. 204; Parry C, p. 23; Wrangell, pp. ciu,
exxxi-exxxii, 60-51, 222-24, 279.
1 Nart», vol. ii. p. 66 ; Nordenskiold, vol. ii. p. 61 ; Payer, vol. i. pp. 184-85,
251 ; Rom, p. 618.
» Nare«, vol. ii. p. 77 ; Parry B, p. 124 ; Wrangell, pp. lii, 38-30, 185, 276.
Digitized by Google
Vol. 50.]
SNOWDRIFT DEPOSITS DISCUSSION".
487
blown dust deposit, though it passed into deposits which had been
re-arranged by water. Part of this lay at altitude© where snow fell
each year, but it was equally well and typically developed below
the level at which snow usually fell, and where it was not preceded
by a long frost nor lasted long enough to form extensive drifts. He
did not think that the true loess could originate from the solid
matter left by melting snow, and it could certainly be formed without
the aid of snow.
Dr. W. F. Hume observed that the views as to loess which still
held the field were three : —
1. The diluvial theory, accounting for it as due to flood-waters set
in motion by volcanic action. This view appeared to be untenable,
if the total absence of volcanic evidence in the main areas where
loess was present wero taken into account.
2. The origin of the European loess as the result of the melting
of large glaciers, having been either originally deposited in lakes
or as iluviatile loam. This view was strongly held by many
Russian geologists, ax>lian action being almost entirely ignored.
3. ^olian action the prime factor, as maintained by Baron Ferd.
von Richthofen, though glacial action might have played a con-
siderable part in originating one type of this deposit. Some deposits,
as in Australia and India, would appear to be entirely due to this
action.
The suggestion made by Mr. Davison would be a subsidiary
aspect of theory No. 2.
The President drew attention to an important paper published
in the 4 Geological Magazine' for 1880 on the Origin of the Loess
(' Subaerial Deposits of the Arid Begion of North America,' by Israel
C. Russell, of the U.S. Geol. Survey, Washington, D.C., U.S.A.,
Geol. Mag. dec. iii. vol. vi. pp. 28(J-205 & 342-350), showing
how a large portion of that deposit may have originated by fine
sediments deposited subaqueously in great, shallow, inland lakes.
The lakes having become desiccated, these sediments have subse-
quently been removed and re-deposited by a;olian action as unstra-
tificd loess.
4 S3
MESSRS. WniTAKER AND JUKES-BROWNE 05
[Aug. 1894,
32. On Deep Borings at Culpord awe? Winkfield, with Notes on
those at Ware and Cheshunt. By W. Wit ITAKER, B.A., F.R.S.,
F.G.S., Assoc. Inst. C.E., and A. J. Jukes-Browne, B.A., F.G.S.'
(Communicated by permission of the Director-General of the
Geological Survey. Head June 20th, 1894.)
C05TEKTS.
I. Introductory
II. The Culford Boring
General Account of the Work.
Description of Samples.
Classification of the Beds.
III. The Winkfield Boring
General Remarks.
Details of the Section.
Remarks on the Geological Divisions.
Notes on the Water.
IV. The Ware Boring
History of the Work.
Description of Samples.
Classification of the Beds.
V. The Cheshunt Boring
General Note.
Samples and Section.
VI. Conclusions
I. Introductory.
A boring at Culford having unexpectedly given evidence of the
underground rise of older rocks in Suffolk, a county in which there
was no such evidence before, we thought that it should be described
before this Society. Another boring, in the parish of Winkfield,
having also proved the presence of Jx>wer Greensand deep under-
ground in Berkshire, by the southern border of the Valley of the
Thames, it occurred to us that it might be noticed at the same
time, as bearing on the same general quostiou, namely, th'e under-
ground extension of beds.
Much delay has occurred in the writing of the descriptions of
these sections, but this is the less to be regretted as it has enabled
us to add a great deal of detailed information concerning the boring
at Ware, and some also on that at Cheshunt. In the case of Ware,
indeed, no details have hitherto been published — only a mere abstract
of the section, and that not accurate in the Cretaceous divisions.
In none of these cases could we print our notes in a Geological
Survey Memoir, all these notes being supplementary to Memoirs
already published ; but we trust that no excuse is needed for again
1 [It in but right to say that, though my name comes first, by disadvantage
of seniority, my colleague has had the larger share of the work in this
paper. -W.W.J
Tage
. 4*S
. 496
. 601
. 506
. 511
Digitized by Google
Vol. 50.] B0RING8 AT CULPORD, WI5KFIELD, WARE, AND CHESIIUKT. 489
bringing bofore the Society a subject of so much interest as that
of the older rocks underground in the South-East of England, in
connexion with which we venture to say that it is of some
importance to get accurate knowledge of the beds above the
old rocks.
We desire to acknowledge the great assistance that we have received
from our friend Mr. W. Hill, who has made some forty microscope-
slides from the rocks found in these borings, sending us descriptive
notes and critical remarks on all of them. These notes and opinions
are embodied in our paper. We have also to thank Mr. J. Francis,
the Engineer of the New River Company, and Messrs. Lo Grand and
Sutcliff, for the information and the specimens upon which the paper
is based.
[Since this paper was sent in to the Society Prof. Dawkins has
made an important addition to the literature of the great Dover
boring, in which he gives details of the Cretaceous and Jurassic
beds.1 It is often a difficult matter to classify beds from specimens
brought up from great depths, and we are disposed to question
some of the classifications in this case, though wo hesitate to
express an opinion without seeing specimens. We should expect
the section of the Cretaceous beds below the Gault, at the site of
the boring, to differ somewhat from that in the cliffs south-west-
ward, to which the author refers, especially as a great difference
seems to bo shown by another deep boring at Dover, already
described by one of us.a
By some oversight the author has noted tho Jurassic beds as
occurring only at two of the deep borings in or near London
(Richmond and Meux's), whereas they have also beon found, moro
lately, at Streatham, the boring at which place has escaped notice
in his table.
We have thought it best to take this opportunity of noticing
these points, rather than to wait for the more convenient season
which depends so much on seeing a largo set of specimens, and
which may be postponed to the good time that is often so long in
coming.]
♦ II. The Culford Boring.
General Account of the Work.
The site of this boring is just outside the northern edge of
Culford Park, about ^ mile S.E. of Rats Hall and 5 miles N.N.W. of
Bur)' St. Edmunds : tho height of the ground being about 110 feet
above Ordnance datum.
The boring was commenced in 1890, and finished in 1891. Its
diameter is at the top 6 inches, and the boring is lined with 5-inch
pipes down to a depth of 583 feet.
It was undertaken for the purpose of obtaining a supply of soft
1 Trans. Manchester GeoL Soo. vol. xxii. pt. xri. (1894) pp. 488-510.
a Quart. Jouro. Geol. Soc. toI. xlii. (1880) pp. 35, 36, and yoI. xliii. (18S7)
pp. 199-203.
Digitized by Google
400
MESSRS. WHITAKBB AND JCXES-BBOWXI OS [Aug. 1 894,
water for some new buildings on the Earl of Cadogan's estate, and
it was expected by the engineers (Messrs. Le Graud and Sutcliff)
that such a supply would be found in the Lower Greensand, as in
the neighbourhood of Cambridge. They were advised by Mr. W.
H. Dalton, who calculated that the base of the Gault would be
reached at about 610 feet from the surface, a prediction which
proved to be within about 5 feet of the truth.
The hope of getting water, however, was not realized : a plentiful
supply of hard water was found in the Chalk, but the sandy beds
below the Gault did not yield any water. The Gault seems to pass
down into sandy clay, below which are alternations of calcareous
stone and sandy material, and at the depth of (537£ feet the bore
entered a hard greenish slate.
Puzzled by this hard rock, and finding that Mr. Dalton was away
from home, Messrs. Le Grand and Sutcliff applied to the Geological
Survey Office for information, sending samples from the lowest part
of tho bore. On examining these we reported that Palaeozoic rocks
had been reached, and that the prospect of obtaining water by
going deeper was very small. At tho same time we pointed out the
importance of the discovery of Palaeozoic rock at so small a depth,
and urged Messrs. Le Grand and Sutcliff to obtain Lord Cadogan's
permission to carry the boring a little deeper — in order to ascertain,
if possible, to what forraation the slaty rocks belonged. The boring
was carried nearly 20 feet deeper, through soft slaty shale with
some harder beds, and was stopped in this material at a depth of
057^ feet.
The following is the account of the boring sent to us by Messrs.
Le Grand and Sutcliff, and we prefer to give this first, exactly as
furnished by them. We will then describe the samples which were
submitted to us, and by their aid will endeavour to determine the
stratigraphic horizons of the beds. Unfortunately the samples
obtained were too few to enable us to do this in a very satisfactory
manner.
Pit (dug)
Chalk and flints
Hard chalk and flints
Chalk-rock [i.e. very hard chalk] with a
layer of flints at the base. Sample 1
Hard chalk with a layer of flints at the base.
Samples 2&3
Hard chalk
Soft chalk
Chalk, rnther hard. Sample 4
Chalk getting like marl
Grey chalk-marl. Sample 5
Gault, dark-grey clay. Samples 6, 7, & 8 .
Sandy Gault. Sample 9
Sandv Gault and stone in alternating layers.
Snmplea 10. 11
Greensand stone. Sample 12
Claystone. Sample 13
Shaly stone. Sample 14
Thickness.
Depth.
Feet
Feet
6
6
341
•347
26
373
16
389
18
407
7
414
4
418
59
477
6
79
5G2
36
508
27
625
11
636
n
637*
640
17*
657*
Digitized by Google
Vol. 50.] BOBX5GS AT CULFORD, WIXKFIELD, WARE, AND CHESHTTKT. 491
Description of Samples.
1 . Bather hard, yellowish, marly chalk, very like the material
which occurs in the marl below tho Melbourn Rock at Whittington,
near Stoke Ferry in Norfolk.
2. Compact and rather hard, homogeneous, white chalk. Under
tho microscope it shows a fine amorphous matrix in which are
numerous single calcareous cells, many of which are empty. It
most resembles slides of Upper Chalk.
3. A flint, black throughout, without any white rind or envelope.
4. Very soft, pulverulent chalk, and in its dry state almost pure
white. It is either one of the softest beds of the Chalk Marl, or
part of a mashed-up core, probably the latter.
6. Light grey marl : effervesces freely, but is nevertheless decidedly
argillaceous. Mr. W. Hill cut a piece of this and reports that its
structure closely resembles the marly Upper Gault of Norfolk ; in
his opinion it is Gault. There was no note of the exact depth from
which the sample was taken.
6. Dark grey marl, evidently a Gault marl, but it effervesces freely
with hydrochloric acid.
7. Phosphatic nodules and fossils, including Belemnitcs attenuatus,
Xtucuht ptctinata, fish-vertebra?, and part of a gasteropod.
8. Dark grey clay, effervesces slightly.
9. Dark-grey, sandy clay. An extra sample from 600 feet is a
dark clay, with larger grains of sand.
10. Very soft, wet, sandy clay ; when washed this is found to
consist of very fine mud enclosing a quantity of sand, the grains of
which vary much in size ; tho greater part — perhaps t wo thirds — of
the sandy material is clear white quartz, partly in rounded partly
in angular grains. Tho residue consists chiefly of small water-
worn fragments of grey slate or argil lite, closely resembling material
occurring in the Palaeozoic rocks below. There are also a few
grains that seem to be glauconite. Probably the bed from which
this sample was obtained is really a somewhat dirty or silty sand,
the fine mud which now binds it into a sandy clay having been
derived from the Gault above and mixed with it in* the process of
boring.
11. Several samples. A greyish-brown stone, from 632 feet,
containing many small brown bodies looking like decomposed oolitic
grains of iron ; a grey gritty-feeling stone ; a piece of lignite,
embedded in brown ferruginous sandstone containing large grains
of yellow and brown quartz ; lastly a fragment of an ammonite.
Both these grey stones arc calcareous, and when sliced and
examined under the microscope are seen to be limestones of a very
peculiar typo. They consist mainly of shell- fragments set in a
matrix of shell-dust, cemented by calcito ; a few grains of quartz
aro seen, but the grittincss of the rock is evidently due to the
shell-fragments, as in the case of the Totternhoe Stono. Most of
these fragments are pieces of cchinoderm-shell, some are molluscan,
and there are a few foraminifera (chiefly Textularia). The brown
Digitized by Google
492
ME88R3. WHITAKER AKD JUEES-BBOWftE OX [Aug. 1 894,
particles in the greyish -brown stone aro not oolitic, but seem to be
merely organic fragments stained by oxide of iron ; many are friable
and break away in the preparation of the slice, leaving empty spaces
with a ferruginous lining, but others remain and seem to be rolled
pieces of shell partially replaced by a yellow-brown mineral, pre-
sumably a decomposed glauconite. Others are stained black by
what may be manganese (it is not cubical pyrites). The grey stone
has less matrix and a greater number of organic fragments, some
rolled and some angular : besides echinodenn and molluscan shell
a piece of Terebratula-skcW and a lattice-work fragment (? coral)
can be seen in the slide, which is traversed by a vein of calcite.
There are also some oval bodies which in shape resemble cyprid-
cases.
12. A light^grey calcareous rock, bearing so close a resemblance
to the grey stone above described that it might be from the same
bed. Dr. Hinde, to whom a slice was sent, remarks that 44 it seems
to be mainly composed of plates and spines of echinoderms, prob-
ably sea-urchins, fragments of molluscan and entomostracan shell,
a few foramiuifera, and an occasional sponge-spicule, but I do not
recognize coral-structure in it. The foraminifera are principally
Te.vlularia, but there are specimens of another genus with perforated
walls." A few grains of quartz are scattered through the slide.
Mr. Hill remarks to us that the general assemblage of organic
fragments and their arrangement is similar to that in some of the
raised coral-reef rock of .Barbados.1
13. A hard, light greenish-grey, slaty rock, showing what seem
to be two sets of cleavage- plunes : one of these slopes at an angle
of about 00° ; the other forms jagged edges on the broken surface
of the block, and seems to be nearly parallel to the veitical face of
the core. Tho block was said to come from 638 feet.
14. One from 647 feet is a mash-up of soft, grey, shaly rock
enclosing fragments of hard slate or argillite. Another from 650
feet is a dark-grey compact rock with white veins : this looked like
a limestone, but did not effervesce with acid and appears to be a
kind of hornstone or argillite with quartzose veins. A third
sample from 657 feet is a dark-grey slaty rock resembling some of
the imperfect slates or killas of Devon and Cornwall, but it mi^ht
equally well be of Cambrian or Ordovician age.
Slides from several samples of these slaty rocks were made at the
Geological Survey Office, and were examined by Mr. Teall. One,
marked as coming from between 645 and 647 feet, is a fine-grained
siliceous stone of the lydianite or hornstone type and is traversed
by numerous white quartz-veins. Mr. Teall describes it as composed
of minute crystals of quartz, felspar, white mica, brown mica, and
chlorite, the first two minerals predominating.
Another, labelled as " shale 657 feet," he describes as composed
of exceedingly fine particles — amongst which a few grains of quartz
and scales of mica may bo recognized.
1 See Quart. Journ. GeoL Soc. voL xlvii. (1891) p. 244, and pi. ix. flg. 4.
Vol. 50.] BORINGS AT CULFORD, WINKFIELD, WARE, AXD CnESHFNT. 403
Slides were also made from the greenish slate, in view of the
possibility of its containing minute organic remains, but though
these slides were examined by Mr. Teall, by Messrs. Sharman and
Newton, as well as by ourselvos, not the slightest trace of any
organic structure has been detected.
Classification of the Beds.
The conclusions to he drawn from the above description seem to
be as follows : —
(i) If the sample from between 373 and 380 feet is from the base
of the Melbourn Rock, the beds below 389 feet belong to the
Lower Chalk. Samples 2 and 3 must iu this case have been taken
from chalk and flints which fell down the bore. No simple of
Totternhoe Stone or of the Bandy base of the Chalk Marl has been
preserved.
(ii) Only one sample in 79 feet of strata between the depths of
483 and 562 feet has been kept, and this proves to be Gault. Wo
are therefore without evidence as to the base of the Chalk, but if
the thicknesses of Lower Chalk and of Gault aro similar to those
near Burwoll and Soham, west of Culford, there would be about
150 feet of the former and 00 of the latter, or 240 feet altogether.
Now, assuming that the Jxnver Chalk in the boring begins at 3^0
feet and that the Gault ends at 025 feet, these two formations are
236 feet thick, which is a very close correspondence.
There ia, however, some little doubt as to the base of the Gault,
for the sample from 000 feet had grains of coarse sand such as
generally occur only in the lowest 5 or 6 feet of the Gault, and it
may bo therefore that the actual base of that division is very little
below 000 feet; the rest of what is termed " sandy Gault" being
similar to that in tho underlying beds described as " sandy Gault
and stone."
As the Gault is likely to be somewhat thinner towards the east,
we do not suppose that more than 30 out of the 70 feet called
"grey chalk-marl" is really Gault. If this inference be correct,
the Ix>wer Chalk at Culford is 143 feet thick, its base occurring at
the depth of 532 feet ; whilo if the base of the Gault bo taken at
005 feet, this division would have a thickness of 73 feet.
With respect to the beds between 025 and 036 feet, the brown
sandstone enclosing lignite has the aspect of ordinary quartzoso
Lower Greensand, but the calcareous beds do not resemble any
part of that group exposed in Cambridgeshire or Norfolk. The.-e
limestones were in fact so different from any rock previously known
to us that we were long in doubt about their age, and the possibility
of their being Jurassic had occurred to us ; but on referring to
Prof. Judd's account of the rocks below the Gault at Richmond 1
we recognized a certain similarity of structure. On mentioning
this to Prof. Judd he very kindly lent us some of the slides which
1 Quart. Journ. Geol. Soc. tol. xl. (1884) p. 738.
Q. J. G. S. No. 109. 2 l
494
MBS8US. WniTAKEH AND J UKKS-BK0W5E OX
[Aug. 1894,
had been prepared from the Richmond samples, and on examining
these we found that the Culford limestones bore a very close
resemblance to the highest part of the Richmond series, i. e. the
top part of that classed as Neocomian by Prof. Judd.
Not only is the general structure similar, but the same varieties
of stone occur: thus one sample from Richmond, at 1141£ feet, is
a grey stone without any brown grains, but consisting of broken
Khell-fragments (echinoid and molluscan), with some cyprid-cases,
a few foraminifera, and a few scattered grains of quartz, embedded
in a dull calcareous matrix. This is similar to the grey limestones
of Culford. Another slide (marked from 1141£, but probably a
little lower than the first) and one from 1144 feet show similar
enclosures, but the fragments are more rolled and scattered, many
are stained by a dark brown material, some partially and some
completely, and the matrix is clear crystalline calcite. These
resemble the rock with brown grains at Culford, in which, however,
the matrix is dirtier and the fragments rather smaller. Both have
very little quartz, and cannot be called sandy rocks.
Such close resemblances in structure between two rocks occupying
the same stratigraphic position are certainly suggestive of identity
in age, especially as we know of no other rock which has a similar
structure.
Of the uppermost portion of this limestone at Richmond Prof. Judd
remarks that ** the rock very closely resembles, both macroscopically
and microscopically, certain varieties of the Kentish Rag." It is
true that the calcareous sandstones which occur in the Ilythe Beds
between Hythe and Sevenoaks, and are known as Kentish Rag, vary
considerably in microscopic structure ; but, so far as we can judge
from the slides that we have examined, they seldom consist very
largely of shell-fragments. Sometimes they contain much quartz
and glauconite, sometimes very little. At Hythe the prevalent kind
of limestone seems to be one containing a large number of spongc-
spicules, with a few shell- fragments, a fair amount of green
glauconite, and comparatively little quartz. Except in the small
amount of quartz, this will not compare with the Culford rock.
There is, however, much resemblance between the finer-grained
stone at Culford and a calcareous stone in the Hythe Beds at Til-
burstow Hill, near Godstone. There is a specimen of this in the
Museum of Practical Geology (Case E, 207(5), and a slide was cut
from it for our insj)ection. The matrix is crystalline granular
calcite, and through this are scattered shell-fragments, sponge-
spiculcs, glauconite-grains and a few quartz-grains, both of these
being small. A few of the shell-fragments show echinodermal
structure, and there are several fora mini t era, including a Ttxtnlaria.
We have also compared the Richmond and Culford rocks with
three slides of Bargate Stone from localities near Godalming and
Guildford, and rind a considerable degree of resemblance between
them. These samples of .Bargate Stone consist mainly of shell-frag-
ments, among which bits of echinoid shell and spines are abundant,
set in a matrix of clear crystalline calcite; the amount of quartz
Digitized by Google
Vol. 50.] BORIXGS AT CULFORD, WINK FIELD, WARE, AND CHE8HTJNT. 495
and glauconite varies greatly, one slide having do visible quartz and
another very little quartz and no grains of glauconite, while in the
third both are in fair quantity.
From these observations and comparisons we think ourselves
justified in concluding that the Culford and Richmond limestones
are of tho same age, and that they belong to the same group of rocks
as the Kentish Rag and the Bargate Stone ; that is to say, to what
is usually termed Lower Greenland, the beds which one of us pro-
poses to call Vectian, but for which Prof. Judd prefers the name
Neocomian.
The fnigment of an ammonite was submitted to Messrs. Sharraan
and Newton, who report that it is unlike any known Cretaceous
species, and most resembles Ammonites Valdaiii of the Lower Lias ;
at the same time, they say that the fragment is too small to be
identified with certainty, and that it might belong to some other
Jurassic species. It would appear, therefore, to be a derived fragment,
like those so frequently met with in the Lower Greensand, and, as
such, is useless for determining the age of the beds in which it was
found.
80 far as we can ascertain, no pebble-bed occurs at the base of
the Cretaceous series at Culford : the account given being that the
boring-tool passed directly from the lowest calcareous stone into the
greenish claystone or slate.
With respect to the Palaeozoic rocks, of which nearly 20 feet were *
pierced in the boring, we are unfortunately able to say very little.
Those who have seen them differ greatly in opinion as to their age.
Mr. W. H. Dalton sees resemblances to the Wenlock Shales, and
would refer them to the Silurian system. He iuforms us that ho
judged chiefly from a sample of soft shale containing "a bit of
limestone resembling that of Upper Silurian." As stated on p. 4U2,
we found this to be not a calcareous, but a siliceous rock. Dr. J. E.
Taylor writes that the softer shaly slate is like the shales found at
Harwich, and considers both to bo of Lower Carboniferous age. For
ourselves we think there is nothing distinctive about them, and that
such shales and slates might occur in any cleaved area of Carboni-
ferous, Devonian, Ordovician, or Cambrian rocks ; but we do not
think they resemble the Upper Silurian rocks of Shropshire, and
that is tho type of Silurian which occurs below "Ware. There is
only one point on which all are agreed, namely, that these Culford
slates are older than the CoaJ-Measures. The angle and direction
of dip could not be ascertained.
So far, thcreforo, as the samples preserved enable us to form an
opinion, the age and thickness of the several formations passed
through are as follows : —
Thickne«w.
Pit (? in Drift)
Upper and Middle Chnlk ..
Lower Chalk
Upper (iaudt
Lower (iimlt
Vectian (Lower Greensand)
Palaeozoic rocks
Feet.
<•>
143
30
43
Depth.
Feet.
0
3*9
o'.V2
«05
K374
0r»?{
M I*
Digitized by Google
496 ME88B8. "WniTAKEK AKD JTKE8-BB0WSE OH [Aug. 1894,
A* already stated, it is possible that the base of the Gault maybe
as low as 625 feet, in which case the Vectian is only 12* feet thick,
but we arc disposed to think the above is the most probable inter-
pretation, and in this Mr. Dalton agrees with us.
III. The Wixkfield Boring.
General Remarks.
In May, 1893, a deep boring was finished at New Lodge, the
house of M. Van de Weyer, in the parish of Winkfield (but only
about 100 yards from the border with Bray), and over 3£ miles
nearly W.S.W. of Windsor Castle. This nite is in the London Clay
tract of the district known as Windsor Forest, from which the work
has to some extent become known as the Windsor boring, a title
to which it has no right.
During the progress of the boring we have been in frequent
communication with Messrs. Le Grand and Putcliff, who made it.
To them we are indebted for a detailed section of the beds passed
through, and for various specimens. In this case also Mr. Dalton
was consulted by the well-sinkcrs.
The site, at the southern border of the grounds, about 150 yards
from the house, and about 130 westward from Nobbscrook Farm, is
218 feet above Ordnance datum, the above measurements being
made not on the ground, but from an Ordnance map (Berkshire,
Sheet 31) on which the site had been marked by Messrs. Le Grand
and Sut cliff.
A small pit was dug, to the depth of only 8 feet, when the
boring was begun, and with the intention of going no deeper than
250 to 350 feet. Consequently, provision was made only for a pipe
5 inches in diameter to be carried down 231 feet, or 17 feet into the
Chalk. It can readily be imagined, therefore, that great difficulties
had to be encountered, and that many expedients were resorted to in
order to take the boring more than 1000 feet deeper than the point
to which the pipes reached : indeed the engineers say, in a letter,
that, " hampered at every step, the marvel to us now is that we
ever reached the Lower Grecnsand," to get water from which was
tho object of going so deep.
It is for its success in this that the boring is notable, such success
being rare in very deep borings — putting aside such a caso asCaterham,
close to the outcrop of the Lower Grecnsand, and various wells in
the Valley of the Medway, where a large amount of water is got by
borings through the Chalk and the Gault into the sand beneath. Of
deeper borings at sites in the London Clay tract of the London Basin
only two others have succeeded in getting water from the Lower
Greensand. One of these is at Loughton in Essex, where water
was found at the base of the Gault, and presumably therefore from
Lower Greensand, at the depth of 1096 feet ; whilst in the other, in
Kent at Chattenden, northward of Chatham, this formation was
entered at the depth of 1162 feet. The boring now described is
therefore the deepest as far as Lower Greensand is concerned,
including the case of Richmond, where the formation occurred at
the depth of 1140 to 1150 feet.
Digitized by Google
Vol. SO.] BORINGS AT CULFORD, WIITKPIKLD, WARE, AND CHR8HUNT. 497
Details of the Section.
f Brown clay
Blue clay
[Loxdok Olat.]
Black [flint] pebbles,
e clay
>wn de
ment-bed]
Blue clay and clay •stones [septaria].
Brown dead [clayey] sand [? base-
[R K im m Bkd8,
78 feet.]
Middle Chalk,
169 feet.
Qreen sand, shells and water [base-
ment-bed]
Mottled clay
Very hard yellow clay
Brown sand, with water
Mottled clay and aand
Light [-coloured] blowing sand ....
Upp.k Chalk. rCUalk and flinU
329 feet. Solid "
raasaeaof flint, < »' »»
several teet " » 9Uc'Ky ";r
♦hiok ;« nn*t " " and brown,
thick, in part. [BIack chftlk
[? Chalk Bock.] Hard grey chalk and flints
fHard white chalk
Grey sticky chalk and flints
„ f, n flint at 578 feet .
(Another account says hard white
clialk, 20 feet.)
White sticky chalk
White chalk
Grey sticky chalk
^ Hard white chalk
Hard, sticky, white chalk
Hard chalk
Hard white chalk '.
Grey gritty chalk
Chalk marl
Hard white chalk
Very bard white chalk [? Melbourn
Kock]
'White and green chalk [? BeUmm-
tclla Marl]
White chalk
Hard white chalk
Free-cutting white chalk
Hard white chalk
Very hard whito chalk
Very hard grey chalk
Hard dark-grey chalk [?Tottemhoe
Stone]
fBlue clayey chalk. Specimen
with minute flakes of mica
and some black specks
Dark-brown clayey chalk ....
Grey chalk, with hard bands*
from 1 to 13 inches thick
Specimen from 927 ft.: like
the hard beds of the Chalk
Marl (with 'spheres' Hill).
Specimen from the ba*o: dark
grey marl, with quartz-grains,
mica-flake*.!! ml black particles
[? glauconite] : small bits of]
glauconitic marl
[Lowkr Chalk,
219 feet.]
Thickness.
Depth.
Ft.
In.
rt.
In.
it
0
n
O
U
54
o
w
t\
0
1
n
U
0
0
115
A ACF
0
15
0
130
0
ft
0
13ft
0
14
I"*
n
14
0
104
()
11
0
175
0
17
0
192
0
22
0
214
0
79
0
293
0
30
0
323
0
159
0
482
0
21
0
603
0
.32
ft
535
ft
7
ft
0
a
0
0
551
0
13
6
564
6
0
6
567
0
15
0
582
0
8
0
590
0
27
0
617
0
6
0
623
0
nt
££*
u
tt4o
1 1
0
Z
u
DOO
u
tl
u
/>— (1
OlV
(*
0
14
a
O
£tl ft 4
oil 4
A
0
4
U
vvo
0
4
u
0
4
0
706*
0
14
0
720
0
6
0
726
0
27
0
753
0
44
0
797
0
12
0
809
0
15
0
824
0
7
9
831
9
17
1
848
10
18
2
867
0
1
0
868
0
21
0
889
0
50 0
939 0
Digitized by Google
408
MESSRS. WHITAKFR AND JUKES-BROWNE
on [Aug. 1894,
UprEB Gbbexsajid. Some resembling the Upper Green-
sand at the Wallingford and M 011 Word borings.
Specimen from 930 ft. 8 in. : dark-grey plastic
Chalk Marl with many glauconite- grains, enclosing
bita of a harder or drier, more glauconitir marl.
After treatment with acid and washing, a bit left
about two thirds of its bulk, consisting almost
wholly of quartz and glauconite. Probably Chalk
Marl has been carried down by the boring-tuol into
the sand. Specimen from 942 ft. 8 in. : hard grey
marl full of grains of quartz and of glauconite.
Specimen from 956 feet: calcareous malmstone,
having a matrix of granular calcite, with many
angular bit* of calcitic shell, many sponge-spicules
and minute scattered grains of quartz and of glau-
conite. This slide also shows a great number of black
specks (pyrites?) which fill chambers of very small
forumintfcra ('Icxtularia and others). Specimen
from 956 ft. 8 in. : hard, compact, grev stone, sandy,
micaceous, fine-grained. Specimen from 960 feet :
hard, compact, grey sandy stone, with some calca-
reous matter. Specimen from 068-970 feet : fine-
grained sandy stone like the last, but with little
calcareous matter
'Gault [clay]. Became dark and sticky
at 994 feet (sample brought up dry).
Specimen from 1006 feet like Lower
Gault ( W. Hill). Hard, drv, friable [ligbt-
§r?y] clay at 1050 to 1050 feet. Then
ark soft clay [grey, with some bits of
a lighter colour], impeding the progrees
of the pipes. Ammonites splendent at
1170 feet, when the clay becomes harder.
Jnoceravms sulcatus at 1170 and 1179
feet (E. T. Newton). Phosphatic nodules
from 1 171 feet
Brown and dnrk-greenish sandy clay. Sand
only observed near the base.' At the base
a layer of phosphatic nodules
Loweb Guekxsand. Fiue, sharp, light-brown sand, of
the ordinary character of that in the Folkestone
Beds. With water
Thickness.
Ft. In.
[Gault,
204 feet .]1
31 0
200 0
4 0
9 0
Depth.
Ft. In.
070 0
1230 0
1234 0
1243 0
Remarks on the Geological Divisions.
The basement-bed of the London Clay being well marked, so also
is the amount of that formation and the thickness of the Beading
Beds. The latter agrees "with what is shown by various other well-
sections in the neighbourhood, in which the thickness of this form-
ation varies from about 70 to over 90 feet, except for Slough, where
it falls to a much lower figure.1
There is some doubt as to tho position of the Chalk Bock, and it
may be that it is tho bed below that suggested which ought to be
so classed. Of course, therefore, the division between the Upper and
the Middle Clialk is somewhat doubtful.
> See Geol. Surv. Mem. 1^89, 'The Geology of London and of Part of the
Thames Valley,' vol. ii. pp. 3-10, 334, 335.
Digitized by Google
Vol. 50.] BORINGS AT CULF0RD, WI5KF1ELD, WARE, AND CHESHUNT. 409
The Lower (^halk is rather thick, and the whole formation of the
Chalk is about 80 feet thicker than under London and 55 feet
thicker than at Richmond. So clayey are some of the specimona
from the Chalk Marl that wo were at first inclined to think, as also
was Mr. W. Hill, that the Gault might have been reached, and
therefore that tho Upper Grcensand was absent — a view that
was of course negatived when the last-named formation was found
to occur still lower. A specimen from 927 feet was submitted to
Mr. W. Brierley (of Southampton), who reports that it is composed
of 62*1 per cent, of calcium carbonate, with a small quantity of iron,
etc., and 37*9 per cent, of clayey matter — a composition not varying
much from that of some highly calcareous Gault.
The Upper Greenland seems to have been reached at about
939 feet, when the boring entered a sandy marl : this may be
from 0 to 10 feet thick, and is underlain by impure malmstone. A
specimen of the latter, from 956 feet, is sandy and has the same
structure as a calcareous malmstone from Selborne, a slide of which
was lent by Dr. Hinde. Each contains about the same amount of
quartz, in very minute graius : that from Selborne, however, having
rather more glauconite and more foraminifera, but rather fewer
spicules and hardly any black specks. A calcareous malmstone
from Reigate, a slide of which was also lent by Dr. Hinde, has much
more glauconite than either of the above and more sponge-spicules.
The Gault is very thick, being from f>3 to 133 feet thicker than
in the deep borings in and around London, tho nearest approach,
anywhere in the London district, being at Shorehara in Ketit
(38 feet less), and the only excess being at Caterham, by nearly
80 feet.
From a geological point of view, it is of course to be regretted
that the boring was not carried deeper, to prove the thickness of the
Lower Greenland and to find by what this formation is underlain.
We may perhaps venture to suggest that it is not likely that
Wealden bods would be found, but that any division of the great
Jurassic series may be represented, and that probably some Jurassic
formation would be passed through before the older rocks are
reached.
Notes on the Water.
The level of the water from the Chalk was 151 feet down, or only
07 feet above Ordnance datum. In September 1890 the supply was
weak, and at the end of November pumping, at tho rate of 3 gallons
a minute, lowered the water from this source 32 feet. This poor
yield from the Chalk is what might be expected from a bore of small
diameter carried through more than 200 feet of Tertiary beds, but
it does not prove that the Chulk hero is practically waterless.
On May 9th, 1893, at tho end of the work, the water from the
Lower Greenland rose to over 2£ feet above the ground. This
water-level steadily rose, as the borehole was shelled out, and reached
the height of 7 feet 8 inches, or more than 225] feet above Ordnance
datum, on May 18th.
The high level to which the water from the Lower Groensand
Digitized by Google
500 MESSRS. WHJTAKER AND JCKES-BROWNE ON [Aug. 1 894,
rises is owing to the height of the outcrops of that formation, aud
probably also to the somewhat free passage of water through it, as
well as to the fact that the source has now been tapped for the tirst
time in the district. In the case of the Chalk, on the other hand, the
nearest outcrop is at the level of the Thames, and a large quantity
of water is taken by various wells. One can hardly expect, however,
that the high level of the water from the Lower Greensand will be
maintained, but rather that it will fall slightly after some time,
especially if other successful borings be made.
[In a communication to this Society, made a short time ago and
not published until after this paper had been sent in,1 Prof. Hull
gave it as his opinion that the water came from the southern outcrop
of the Lower Greensand rather than from the northern one. Iu
this we agree, as the former is broad aud unbroken, whereas the
latter is narrower and broken. We do not, however, see with him
(as one of us said at the time) that there is any evidence that
the southern outcrop is divided from the northern one, near
Windsor, by the uprise of older rocks (as shown in the section
which he exhibited). It may be so ; but, on the other hand, it may
not. There may be continuity here, though there is discontinuity
under London ; and at present we are without evidence, knowing
only that water-bearing Lower Greensand is present.
The woodcut from this section has been altered to show the
continuity of the Gault over the ridge of old rocks, in deference
to remarks made in the discussion on the paper.3 While thanking
tho author for this courteous acknowledgment, we must be allowed
to differ from him in the opinion that " the question is one which
is entirely conjectural"; for of the many borings in the London
Basin that havo been carried deep enough, every one has proved the
presence of Gault, and in one only, at Harwich, has it been found
to be thin.]
The following chemical analysis of the water from this boiing is
not without geological interest, for in containing a comparatively
large amount of common salt it follows the rule of many other
deep well-waters, both from Cretaceous and from Jurassic beds.
The difference between the analyses of water, from wells sunk through
a good thickness of Tertiary beds into the Chalk und from wells in
which the Chalk is at or near the surface, has been commented on
by one of us,8 who, however, had not at the time read a paper
by Mr. K. Warington, in which much light is thrown on the
subject.* It seems as if tbe salts once held in the higher outcropping
parts of a permeable formation bad been gradually dissolved out by
the long-continued passage of water down and through them, such
salts being then carried in the water to lower parts, whereas in
those parts where the beds are saturated and from which the water
cannot escape tho contained salts are retained.
1 Quart Journ. Geol. Soc. vol. 1. pp. 152-155 (May 181)4).
8 Und. p. 154.
s Geol. Surv. Mem. 18rP-, *Tbe Geology of London and of Part of tbe
Thames Valley,' vol. i. pp. 514-516, 533 and table opp.
4 Journ. Cbem. Soc. vol li. (1867) pp. 544, 545.
Digitized by Google
Vol. 50.] BORINQ9 AT C OXFORD, WINKFIELD, WABE, AND CHESHUNT. 501
Analysis of a sample of water received from Messrs. Lo Grand and
Sutcliff, 27th May 1893, from New Lodge, Windsor Forest,
at the depth of 1243 feet, by Dr. B. Dyer.
Grains.
Total dissolved matter 01*74
Loss on incineration of residue *S4
Chlorine in chlorides (equal to chloride of sodium 43 37). 20-32
Free (actual or saliue) ammonia *045
Albuminoid (organic) ammonia *0l)3
Oxygen, absorbed by oxidizable organic matter, etc., from
a solution of permanganate of potash at a temperature
of 80° Fahr In 15 minutes. -003
„ „ In 4 hours . . "011
Phosphoric acid traces
No nitrogen in nitrates.
Hardness before boiling 3°, after boiling 0°.
Appearance in two-feet tube turbid. Microscopic examination
satisfactory.
The dissolved matter consisted of the following (in grains) : —
Carbonate of lime 2*24^
Carbonate of magnesia *73
Carbonate of soda 4*99
Sulphate of soda 9*17 ^ 61*74
Chloride of sodium 43*37
Oxide of iron and alumina *28
Silica, traces of organio matter, etc. *90>
" So far as regards organic matter this water is remarkably pure,
as would be expected from the depth. The most remarkable
feature about it is the presence of a large quantity of common salt.
This of course is not prejudicial to health, though persons of delicate
palate might detect a faint trace of salt. The hardness is only
3 degrees, so that for laundry purposes the water would be
economical. It would also be excellent for boiler purposes, in the
sense that it would uot form a crust; though a steam-boiler, of
course, would want occasional blowing-out — owing to the con-
centration of salt."
IV. The Ware Boring.
History of the Work.
The site of this boring is on tho alluvial flat of the River Lea,
between tho Hertford Branch Railway and tho stream from
Chadwell Spring, and | mile N.E. of that spring. It is marked
by tho word " Well " on the Ordnance map (Hertfordshire,
Sheet 29). The level of the surface is about 110 feet above
Ordnance datum. Tho work was undertaken by the New River
Company (who have given the name Broadmead to this Pumping
Station), partly for the purpose of obtaining a larger water-supply
from the Chalk, and partly with the object of ascertaining whether
water-bearing Lower Greensaud could be tound below the Gault.
Digitized by Google J
502
MESSRS. WHITHER AND JUKES-BROWNE ON
[Aug. 1894,
The work was begun in 1 877, and the Gault was pierced early in
1879, Paheozoic rocks being found below it at a depth of 79<>4 feet.
A core of the Palaeozoic rock was examined by Mr. Etheridge,
who found that it was full of Wcnloek fossils, and ho accordingly
announced the existence of Upper Silurian Beds below Ware in a
letter to the 'Times ' dated May 16th, 1879.
A brief account of the boring was subsequently given by
Mr. Jas. Barrow,1 who assigned the following thicknesses to the
several formations, but gave little geological information about
them : —
In 1880 Mr. Hopkinson published a paper * On the Recent
Discovery of Silurian Hocks in Hertfordshire,' 8 but he did not
discuss the other formations.
Mr. Etheridge adopted and reprinted Mr. Barrow's account of the
section in his Presidential Address to the Geological Society for
1881.' He added some further particulars about the Palaeozoic
rocks, but did not give any description of the Cretaceous rocks, nor did
he state the grounds on which thicknesses were assigned to the Chalk
Marl and Upper Greensand respectively. He repeatedly mentions
the occurrence of 18 inches of " Lower Greensaud of the Carstone
type " below the Gault, but he gives no evidence for the identification
of any particular samplo as 4 Carstone,' and we cannot accept this
statement as proof of the existence of Lower Greensand. To this
point we shall recur in the sequel.
No fuller account of the rocks traversed by this boring has ever
been published. The importance of the discover}' of Silurian rocks
seems to have so dwarfed all interest in the Cretaceous beds, that no
careful examination of them was made at the time. Had Ware come
within the scope of any Geological Survey memoir that was in hand
alter the boring had been made, one of us would probably have hunted
for further information, as in the case of the Cheshuut (Turnford)
boring, of which a fairly full account has been printed (see p. 508).
Fortunately the New River Company kept a set of specimens from
both borings, and their Engineer, Mr. J. Francis, having kindly
sent us portions of these, we are now able to give some details and
to correct the short statements already published about the boring
at Ware — statements which one of us has reproduced, though with
some doubts.*
1 Proc. S. Wales Inst. Engine*!*, vol. xi. no. 7 (1870), p. 322, pis. W, 51.
2 Trims. Watford Nat. Hist. 80c. vol. ii. pt. 7 P 241, pi. ii.
3 Quart. J'nirn. Gool. Soe. vol. xxxvii. (lS^l) Vntc. p. 230.
4 Irons. Ilcru. Nat. Iliat. Soc. vol. iu. pt. b (lbfio), p. 171*:
Shaft 34 feet ; the rest bored.
Fret.
Surface-earth, gravel, and sand 14
831*
Digitized by Google
Vol. 50.] B0RING8 AT CULFORD, WISH FIELD. WARE, AND CHE8HUKT. 503
Having examined the samples sent us from the Ware boring we
selected 20, about which it seemed probable that the microscope
would reveal more exact information. These were sent to our friend
Mr. W. Hill, who has been good enough to slice and examine them,
and to furnish us with a written account of the minute structure of
each slide.
When a sufficient number of samples have been preserved from
the strata traversed by a boring, we think that they deserve a more
careful and detailed description than specimens obtained from a
quarry, because the section ia not open to observation and yet may
be far more extensive and important than any quarry-section. Wo
propose, therefore, to give a general description of all the specimens
sent us by Mr. Francis, inserting Mr. Hill's notes on those specially
examined by him.
Description of Samples.
The figures represent the depth in feet from the surfaco from
which the sample was taken, but Mr. Francis informs us that many
were cut off cores of more than a foot in length, and consequently
the depth assigned may not be exact, though near enough for all
practical purposes.
116. Soft white chalk. Under the microscope shows a fine
amorphous matrix with a fair number of small shell-fragments,
lteserables chalk from the zone of Micraster cor-testtuliiuirium.
145 & 149. Soft white chalk ; that from 141) has a thin streak of
gTey marl. It was sliced by Mr. Hill, who describes it as
consisting mainly of fine amorphous material in which can bn
seen a fair number of thin-shelled spheres, some foraminiferal
cells, and many minute TertularUe, with a few small shelly
fragments. The marly part contains a greater number of larger
shell-fragments, arranged with their longer axes in one direc-
tion, as if by current action.
ICO, 172. Soft white chalk. 172 consists chiefly of amorphous
material, with many spheres and some small shell-fragments.
174, 178. Firm, rather tough chalk, with wavy grey streaks of
marly material.
211, 212. Rather hard white chalk. Of 211 Mr. Hill says :— " A
good specimen of Middle Chalk ; spheres are fairly abundant,
the majority thin-shelled ; a few large Globiyerina occur ;
shell-fragments are few and small/'
231, 246. Soft white chalk.
2*7, 340. Firm white chalk.
3*7. Rather hard white chalk. A slice showed the usual characters
of the lower part of the Terebratulina gracili*-'/.one. " Spheres
with a fairly robust shell are abundant ; Globiyerinrw common
and large ; shell-fragments few, but two large Inoceramus-
prisms occur in the slide."
411. Hard creamy-white chalk. In a slide of this Mr. Hill finds
" shelly fragments abundant, some consisting of many united
prisms (J noreramus) ; spheres are abundant and robust* It
clearly comes from the zone of iHOCtrumux mytiloides"
504 MESSRS. WHITAKER AKD JCKES-BBOWXE ON [Aug. 1 894,
423, 427. Very hard, creamy-white chalk, like the more solid parts
of the Melbourn Rock. This is confirmed by the oxaminatiuu
of a slide prepared by Mr. Hill from 427, which has the
structure of the lower part of the Melbourn Rock.
430. A soft, greyish, marly chalk. Of this Mr. Hill reports that it
presents a marked contrast to the preceding, and resembles the
marly chalk of the Belemnitdla jtlena-zone near Hitchin.
443, 470, 47b', 500. Firm greyish-white chalk, 443 being rather
hard, the others softer ; 500 is as white as 443.
510, 511, 512. Soft grey chalk.
517, 525. Rather hard grey chalk.
530, 550, 550, 558. Rather hard grey Chalk Marl.
509, 579. Firm grey Chalk Marl. Having cut slides from both,
Mr. Hill writes that they are characteristic Chalk Marl, a
certain amount of fine siliceous matter being present iu the
calcareous mud of the matrix. 509 is rather sandy and shelly,
the shell-fragments being largo for Chalk Marl. 579 is less
sandy and shelly. Glauconite-graius are common, but small
in 509 ; larger in 57S>.
585. A rather hard, grey, sandy and micaceous chalk. Abundant
flakes of white mica aud minute glauconitc-grains can be seen
with a lens. Mr. Hill describes this as containing ** much
inorganic matter, fine quartz-sand to a large extent replacing
the shell-fragments of the chalk, and still finer argillaceous
matter preponderating over the calcareous material iu the
amorphous matrix. There is much glauconite in small grains,
but these are larger and darker than those in the overlying
beds, marking an approach to the Greensaiid. A number of
foraminifera and a few calcareous spheres occur.''
587, 588. Greenish, sandy, glauconitio and micaceous marl. In
microscopic structure this might be called Greensand, as both
quartz and glauconitc-grains aro abundant and of fair size : but
there is still a considerable amount of amorphous calcareous
matter. Mr. Hill writes that it much resembles a slide from the
base of the Chalk Marl near Tring, believed to have come from
Ivinghoe, but is rather coarser in grain. It may therefore be
regarded as a fine-grained variety of Chloritic Marl.
590 ? The depth-label of this sample has been lost, but we think the
sample must have come from here, for it is a dark-grey sandy
marl enclosing large grains of quartz and of glauconite,and con-
taining patches of darker and more sandy material ; also two
nodules of dark grey phosphate and several fossils (Ptcten inttr-
stritttus, P. orbicularis, a small oyster, and many broken frag-
ments of Inoceramw). It resembles the representative of the
Cambridge Greensand formerly worked at Sharpenhoe in Bed-
fordshire.
591 , 592, 004. Fine-grained, grey, marly, glauconitic and micaceous
sandstones, 592 containing a light-brown phosphatic nodule.
Theso much resemble the very fine-grained micaceous sand-
stones of the Upper Gault or Upper Greensand in Rucks, where
the so-called Upper Greensand is thinning out. All are rather
heavy in the baud.
Vol. 50.] BORINGS AT CTJXFORD, WINKFIELD, WARE, ASD CHESHUNT. 505
613. Lighter-coloured, glauconitic and micaceous sandstone, of much
less specific gravity. This Mr. Hill recognizes as an Upper
Greenland Sponge-bed. " The chief constituents are quartz-
sand, sponge-8picules and glauconite-grains, with a few shell-
fragments and foraminifera. These materials are closely
packed together, and are cemented partly by crystalline calcite
and partly by silica in the amorphous colloid condition. Both
calcite and silica seem to permeate the whole rock, and some-
times masses of calcite are surrounded and isolated by the
silica. Both seem to have been derived from the organic
remains of which the rock must in the first instance have been
largely composed, and to a certain extent the two minerals
have replaced each other. Thus the siliceous spicules are now
almost entirely replaced by calcite-casts (?of their canals) ; only
a few remain in their original state, and in these the spicular
canal is usually filled with glauconite. Colloid silica in a
globular form is abundant. The glauconite-grains, though
abundant, are rather small."
621. A light-coloured siliceous stone of low specific gravity. On
examining a slide of this Mr. Hill found it to be an interesting
rock. He describes the matrix as 44 almost entirely colloid
silica, partly in minute masses like tiny bits of gum arabic,
partly in discs or globules, the latter irregularly scattered in
patches. In this matrix are dispersed small grains of quartz,
broken sponge-spiculcs, with a few shell-fragments, and a few
foraminifera. Tho siliceous miitrix being comparatively clear,
the other ingredients stand out conspicuously."
622, 628. Calcareo-siliceous rocks, heavier than the last, and
externally resembling calcareous malmstone. Describing a
slide cut from 622, Mr. Hill says 44 the mass of it consists or.'
definite, separate calcite-crystals of irregular size, set in a mat rix
of fine calcareous material. There arc many spicules, the silica
of which is replaced by calcite, and there are also many
residuary spicular canals in glauconite. Quartz-grains, though
abundant, are well separated, but no colloid silica of any kind
was observed. Glauconite-grains are small and not abundant."
628 is a similar rock.
632. A fine, dark-grey, silty clay. This, as would be expected from
its external aspect, is regarded by Mr. Hill as a Gault clay.
Under the microscope the mass of it is seen to be a fine,
brownish, inorganic material, with much fine quartz-sand.
Small glauconite-grains occur, but not abundantly, and there
are also broken glauconitic spicular casts. Thread-like fila-
ments (? mica-flakes in transverse section) are common, and
there are some larger crystals whose striation and frayed ei.ds
suggest felspar.
658. A dark-grey clay, with a soapy feel ; effervesces with hydro-
chloric acid, and is therefore somewhat calcareous.
670 to 725. Nine samples of dark-grey clays; all very fine-grained,
homogeneous Gault clays.
790. A fine, compact, dark-grey clay. This was sliced and examined
506 MESSRS. WHITAKER AND JUKBS-BBOWNB ON [Aug. 1 894,
by Mr. Hill, who describes it as consisting of very fine
argillaceous matter having a brownish tint in thin slice. In
it are some large glauconite-grains curiously arranged in rows,
and a few small quartz-grains.
796. A sample of dark, dull-green sand, held together by earthy
matter. When washed it is seen to consist partly of glauconite-
grains and partly of small bits of quartzose and siliceous rocks ;
the glauconite-grains are quite as numerous as the others, but
even-sized and smaller than many of the quartz-grains. Some
of the quartz is clear, but most of the grains are dirty from
enclosures. There are many rolled grains of lydianite and fine
siliceous grit, some of slate and some of a brown rock. A few
shell-fragments occur, and under an inch-objective two or
three foraminifera were seen, but they are scarce.
800. Grey Bhelly limestone of Wenlock type, full of bra chio pods
(many specimens of Leptrrna tranwersalis) in a calcified shelly
matrix. Auother sample is a dull earthy limestone with
Lept/ma, Orthis, and other fossils.
802. Dark-grey earthy mudstone, with a shelly layer containing
Lej)tctna transversalis^ Pentamerus linguiferl^ Orthis elrgantula,
and other fragments of shells. Another piece of hard grey
mudstone with scattered shells.
804, 809. Hard, earthy mudstonos, slightly calcareous, with shelly
layers, composed chiefly of Lejtttma and Orffcw-shells.
827. Two samples of dark-grey calcareous sandstone, with many
fossils (Pentamtrus tjaleatxts, Orthis elegantula).
Classification of the Beds.
From the preceding data, and from information given by Mr.
Francis, we are able to construct the following tabular view of the
succession at Ware : —
AlluTium and River Drift
Upper Chalk
Middle Chalk
Lower Chalk
Upper Greensand
Gault
Wenlock Beds
Thickness.
Feet.
17
?183
227
103
40
icq
35
Depth.
Feet.
17
200
427
690
(WO
7WU
831$
In comparing this with the section previously published it will
be 'seen that wc have been able to divide the Chalk in accordance
with modern views, and that we have considerably curtailed the
thickness of the Upper Greensand, which had been previously given
as 77 feet, although one of us had suggested that this was too great
a thickness. The older account places the base of the Chalk Marl
at 50S feet, but the specimens prove that it lies much lower than
this ; the sample from 5*5 feet is undoubtedly a chalk, though very
micaceous and glauconitic : that from 591 is undoubtedly a green-
sand ; the junction must therefore lie between these depths, aud we
Vol. 50.] BORINGS AT CULPORD, WINKPIELD, WARE, AND CHBSHFNT. 507
have found reason to place it at about 590 feet. The Upper Green-
sand, then, is about 40 feet thick, and cannot be more than 44 feet.
With regard to the supposed Lower Greensand, wo cannot accept
the idea of its existence. The material found at the base of the
Gault, and resting on the Wenlock Beds, is just such a basement-
bed as might be expected in such a position. It consists of the
debris of Palaeozoic rocks mixed with glauconite, and so far as its
mineral composition goes it might belong to any member of the
Cretaceous series. One of us had already suggested that this bed
might be the base of the Gault, though without any evidence. It is
satisfactory to be able to take out so very thiu a representative of
tho Lower Greensand.
As a matter of fact, there is generally a bed of such sand at the
base of the Gault ; not only does it occur at Folkestone above the
basement nodule-bed, but also below London, in the boring at Meux's
Brewery, where the base of the Gault is described as follows 1 : —
Greensand and clay 2\ feet.
Seam of pbosphatio nodules and quarttite-pebbles \ foot.
Again, at Richmond, the lowest bed of the Gault is very sandy,
full of glauconite-grains, and passes down into a pebble- bed con-
sisting of phosphate-nodules, fragments of Pakcozoic rock, and sand,
from the same source.3
We do not know whether any phosphate-nodules occurred at
Ware, but the 18 inches of sand is evidently similar to that in the
same position at Richmond and London.
With regard to the Wenlock Beds, these were originally described
by Mr. Etheridge in 1879 as • Wenlock Shale ' ; but Mr. Hopkinson in
the paper before mentioned states that there were thin intercalated
beds of limestone. This is confirmed by the samples before us, which
are all either of hard mudstone or of limestouo ; and also by the
specimens preserved in the Museum of Practical Geology. Mr.
Hudler informs us that the core referred to by Mr. Etheridge is over
3 feet long and has a circumference of 3£ feet ; it consists of dark-
grey mudstone, slightly calcareous, and including thin bands of
brownish limestone ; it is marked as coming from 826 feet. This
is probably the depth of the base of the core, as samples of similar
material were sent us from 827 feet. There are also at Jermyn Street
three specimens from 820 feet, ono a limestone containing Stro-
phomtna rhomboidali*, the others of mudstono containing Phacops
camlulus and Ischadites Ktrnvji.
In calling these beds 4 Wenlock Shale ' Mr. Etheridge probably
used the term in a strutigraphical, not in a strictly lithological
sense ; but considering the frequency and purity of the limestones,
which are not merely calcareous concretions, it is quite as likelv
that the beds represent the Wenlock Limestone as the Wenlock
Shale. It will be safer, therefore, to speak of them merely as
Wenlock Beds.
1 Quart. Jnurn Onl. Sue ^ol. xxxiv. (1878) p. tfl'J.
a Or. fit. vui.xl. (lN-i) i>. 7o7.
50d
MESSRS. WniTAKEK AND JVKKS-BROWXE ON
[Aug. 1894,
V. Thb Cheshunt Boring.
General Note.
This borinfc, like that at Ware, was made for the New River
Company. Its site is on the western side of the high road between
Cheshunt and Wormley, where the word * Turnford ' is engraved on
the old I -inch map; hence it is known to the officials of the New
River Company as the Turnford boring, but as this is only the name
of a hamlet and not that of a village, it seems better to speak of it
as the Cheshunt boring, as has already been done by one of us.
The surface-soil at the site is gravel ; the level is about 110 feet
above Ordnance datum, and only a few feet above the alluvium of
the River Lea, which lies to the eastward.
So far as we can loaru, the boring was begun in 1878, and was
completed in 1879. The results were partly noticed by Mr.
Etheridgo and by Mr. Hopkinson 1 ; a more detailed section was
given by one of us,2 and this was afterwards corrected and much
enlarged, partly from au inspection of specimens.*
Mr. J. Francis, the Engineer of the Company, having kindly
funiished us with specimens of all the samples retained at his office,
we are now able to add some further details and to prepare a still
more accurate account. Unfortunately, however, no samples from
the Upper or from the Middle Chalk seem to have been preserved,
so that we cannot fix the horizons of the Chalk Rock and of the
Mel bourn Rock as we hoped to have done.
Before noticing these samples wo may supply a deficiency in the
former account of the section, and that from information also given
bv Mr. Francis. No record of the top beds had come to hand, and we
were without information as to the Drift and the Loudon Clay, and
with but little as to the Reading Beds and the Thanet Sand. The
succession of beds above the Chalk is now given as follows : —
tR,v„D.„T.]
[Los don Clay,
i» feet.]
[Reading Beds,
36 feet.]
' Yellow clay
Blue clay
Blue sandy clay
Blue shelly clay [basenient-bed].
f White sand
Mot tied clay
Grey sand with lignite
Grey and black [Thanet] sand
Thickn*
Feet.
10
4
12
2
H
4
27*
10*
Depth.
Feet.
4*
Hi
1.4
30*
4if
49
53
91
1 Pop. Sci. Rev. n. ser. vol. iii. (1879) p. 290, and Trans. Watford Nat. Hist.
Soc. vol. ii. pt. 7 (1HJ«0). p. 241.
a Trans. Herts. Nat. Hist. 80c. toI. iii. (1885) p. 176.
3 Geol. Sarv. Mem. 1889, 'The Geology of London and of Tart of the
Thame* Valley,' vol. ii. p. 50.
Digitized by Google
VoL 50.] BORINGS AT CULFOKD, WINKPIELD, WARE, LSD CHE8HUNT. 509
The division between the Reading Beds and the Thanet Sand is
rather doubtful, and the depth to the Chalk is 11| feet less than
was given before. This is for the most part, if not altogether,
explained by the surface from which the above measurements were
made being at least 8 j feet, and perhaps rather more, below the
original surface of the ground from which the earlier measure-
ments were started.
Samples and Section.
Wo now give descriptive notes of the samples sent us by Mr.
Francis, including the remarks made by Mr. W. Hill on eight
specimens which ho was kind enough to cut and examine for us.
At 630 feet. Rather hard, whitish chalk, evidently belonging to the
top of the Lower Chalk.
At 722 and 733 feet. Hard, light-grey chalk.
At 734. Soft, grey, marly chalk.
At 730. Firm grey chalk.
At 740. Very hard, whitish, gritty chalk, with large scattered grains
of glauconite. This was sliced by Mr. Hill, who describes it as
very full of shell-fragments with many foraminifera and
calcareous spheres, and a few sponge-spicules replaced by
calcite. Moreover the rock is indurated by infiltrated calcite.
It resembles the hard rock-bed which occurs in tho Chalk Marl
of Risborough (Bucks), excopt that it contains much less quartz
and glauconite.
At 750 and 754. Soft, grey, marly chalk.
At 759 and 700. Rather hard grey chalk. That from 700 has been
cut, and is described as a chalk-marl with rather a large
quantity of even-sized shell-fragments, with here and there a
larger prism of Inoceramus-*)iQ)l. The quartz-grains are also
email. Glauconite, calcareous spheres, and foraminifera are
present, but not abundant.
At 702. Soft, grey, marly chalk.
At 703, 704, 705. Firm, grey, silty chalk.
At 770. Soft, dark-grey chalk-marl.
At 771. Hard grey chalk. This was sliced, and found to be a shelly
chalk-marl with many grains of glauconite ; but with only a
very few small grains of quartz : it is practically without quartz-
sand.
At 774 and 779. Mottled dark- and light-grey marls.
At 780. Rather hard light-grey chalk.
At 784. Grey, mottled, sandy and glauconitic marl. This consists
largely of quartz-sand and glauconitc-grains, which are thickly
packed in a matrix of amorphous material, the proportion of
calcareous atoms not being large. We thought this might be
tho base of the Chalk Marl, but Mr. Hill regards it as Green-
sand. There are no spicules or foraminifera, and very few
shell-fragments.
Q.J.G.S. No. 199. 2 m
510 JIRBR*. WHITAKER AKD JUXES-BBOWNE ON [Aug. 1894,
At 790. Soft, fine-grained, greenish-grey micaceous and glauconitic
sand.
At 800. Hard, grey, siliceo-calcareous rock. Under the microscope
this was found to consist of sponge-spicules replaced by calcite,
with scattered grains of quartz and of glauconite and a few
foraminifera. There are also many glauconite-casts of
spicular canals. All these ingredients are cemented together
by crystalline calcite, which is made opaque by a previously
existing matrix of finely granular calcite mixed with fine,
amorphous, inorganic material. Silica occurs throughout the
slide, and in open spaces where it can be well viewed it appears
to be both colloid and chalcedonic. Colloid globular silica is
also present, but in patches scattered through the field of the
slide.
At 808. Fine grey sand, with much mica and small grains of
glauconite.
At 810. Compact, grey, calcareous sandstone, with glauconite and
mica.
At 811, 813, 814. Soft fine sand, grey, micaceous, and glauconitic.
At 816. Hard, compact, dark-grey, sandy limestone, enclosing
numerous small grains of glauconite and of mica.
At 818. Grey calcareous limestone. Mr. Hill finds that this con-
sists chiefly of calcite, partly in minute crystals and mixed with
a small proportion of inorganic matter to form a matrix, partly
in larger separate crystals. With these latter are grains of
quartz and of glauconite, a few foraminifera (Globigerina and
Tea tularia), and a few spheres, but no colloid Bilica.
At 819. A friable, grey, sandy and glauconitic marl.
At 825. A fine calcareous sandstone with large glauconite-grains.
This is similar to the last, but differs in having more glauconite
in larger grains.
At 836. A dark-grey, silty, and slightly calcareous clay. The
microscope shows this description to be correct. There is
much fine inorganic material, somo fine quartz-sand, and some
fine calcareous matter ; no glauconite. A similar sample conies
from 840 feet.
At 844. A clean, smooth, unctuous clay.
At 850. A somewhat silty grey clay.
Eight samples between 860 and 914 are ordinary, clean, grey
Gault clays.
At 925. Hard grey clay, with phosphate-nodules and some small
specimens of Inoceramus coneeniricus.
928 to 980 (eight samples) are compact grey clays.
Mr. Francis informs us that thcro was at or near the base of the
Gault (980 a feet) a layer of dark sand like that at Ware. One of us
has also seen a sample of phosphatic nodules and broken belemnites
coming from 980£ feet, so that thero can be little doubt that the
basement-bed is like that at Richmond and at Meux's, namely, a
nodule-bed with greensand above.
Digitized by Google
Vol. 50. J BORING 8 AT CXTLFORD, WINKFIELD, WARE, AND CHE8HUNT. 511
Below the Gault bard dull-purple shale or mudstone was found,
and similar material was penetrated for 29^ feet. This rock was
identified as Devonian by Mr. Etheridge, from its fossils. It is said
that the dip was ascertained to be about 30° S.E. A sample sent us
by Mr. Francis has tool-marks on the outside, and if these are taken
to be horizontal the divisional planes show a dip of 40°. There are
specimens in the Museum of Practical Geology at Jermyn Street.
From the data above given and those published in the * Geology
of London ' we have constructed the following abstract of the beds
proved by this boring : —
Hirer Drift and Eocene Beds
Chalk, with many layers of flints
Chalk, described as • chalk-rock '
Hard tough chalk
Chalk, described as ' chalk-rock '
Chalk of Tarying hardness, some beds hard, some soft,
and some tough. This is' probably all Middle
Chalk '.
Chalk, described as hard and tough, with 7 foot of
mild chalk in the middle (? Lower Chalk)
Hard whitish chalk
Tough light-grey chalk
Alternations of soft grey marl and hard chalk
Firm, grey, silty chalk and chalk- marl, with two beds
of hard grey chalk
Chalk Marl, passing down into Cbloritie Marl
Upper Green sand. Fine greenish sands, with bed*
of hard calcareous sandstone at intervals, the [
hut at 825 feet |
Gault. Silty calcareous clays in the upper 20 feet,
then compact grey clays, with a bed of greensand
and phosphate-nodules at the base
Devonian. Hard dull-purple mudstone*
Tlmknes*.
Feet.
15
46
a
Depth.
Feet.
102*
«HK>
378
424
430
170
000
25
35
73
29
625
660
733
762
17
4
779
783
44
827
1534
29$
980*
1010
VI. Conclusions.
Amongst points of general interest is the fact that the floor of
older rocks has now been struck at a much less depth than before.
Ware held the first place with a depth of 790| feet, but now Culford
takes it with only 637J, or 159 loss, measuring from the surface.
For the proper consideration of tho subject, however, it is needful
to refer the depth of the various borings to one level instead of
reckoning from the surface, in which latter case the height of the
ground affects the result. This height is, of course, a varying factor
which has nothing to do with the position of the older rocks, being
due to actions that have taken place in late geologic time, to erosive
work of a purely superficial kind, affecting the thickness of the
Tertiary beds and sometimes of the Chalk, but disconnected from
all other bedB beneath. The depth from the surface, depending as
it does on the level of the ground, is a matter of no momont,
except locally.
Digitized by Google
512 MLSSKS. W11ITAKER AKD JUKES-BROWNE OX [Aug. 1 894,
The only standard of level that naturally occurs to us is the
Ordnance datum, or mean sea-level, as that is the only one easily
and universally available. In the following remarks, therefore, we
shall refer to depth below Ordnance datum. In the case of Oulford
and Ware, however, the reference of the figures to this datum makes
no difference, the two sites being at about the same level.
In this matter it is noteworthy that heretofore the oldest rocks
yet reached by deep borings in South-eastern England are those
that come to the highest level ; Silurian beds having been reached at
Ware, Devonian at Cheshunt and London (Meux's), Red Rocks of
doubtful age, but now generally thought to be Old Red, at Streatham
(where something suggested that the passage-beds from Silurian
to Old Red had been touched), Crossness, Kentish Town, and
Richmond, this last being the deepest, and Carboniferous beds at
Harwich and Dover, as well as at Burford, in the J urassic tract of
Oxfordshire.
Again, Ware is the most northerly of the deep borings in and
near London, where they most do congregate, and it shows not only
a slight northerly rise of the floor of older rocks, but also a rise
in the divisions of those rocks, resulting in Silurian beds coming
next beneath the Gault.
These two points tend, therefore, to give some slight support to the
view that tho old rock at Culford may be pre-Carbonifcrous, and
perhaps pre-Silurian, in ago. Not that this support is worth much,
but, having so little whereon to float conclusions, even a straw must
be taken into account.
On the other hand, however, the fact that at Harwich, which is
nearer to Culford than any other of these deep borings, it is Car-
boniferous slate that has been found, and that this is, in some
respects, not unlike tho harder parts of the Culford rock, naturally
leads the sanguine to hope, if not to expect, that the latter too may
be of Carboniferous sige. Should this view be right, the likelihood
of still higher Carboniferous aud coal-bearing rocks occurring
underground somewhere in the Eastern Counties is of course
greatly increased.
The nearness of older rocks to the surface at Culford was un-
expected by us : porhaps, indeed, no geologist would have ventured
to predict that such rocks would have been reached there, except by
a boring of much greater depth. One might fairly have expected
to go at least 1000 feet, and to have found the Lower Greensand
and the Jurassic Series well represented, more especially perhaps
the latter, seeing that the outcrop in the neighbourhood of Ely is
within 20 mUes of Culford.
The accompanying table shows the relations of the various borings
that reach the older rocks in the London Basin, including therein
the Chalk tract as well as that of the Tertiary beds. The point
clearly brought out by it is the sinking of the floor of older rocks
southward, in the district over which the borings occur, the only
exceptions being Harwich, which should come second in the list, and
Digitized by Google
Vol. 50.] BO KINGS AT CULFORD, WISKFIELD, WAKE, AND CHESHTJNT. 513
Dover, which should chango places with Richmond, according to
northing. Both exceptions, however, arc far eastward ; but while
the former shows an easterly fall, the latter shows a rise in that
direction. They are also the only two borings that havo proved
the presence of Carboniferous beds.
That the northerly rise of the older rocks continues underground
beyond the neighbourhood of Culford wo can hardly expect, and we
know that, farther northward (in Norfolk), at Yarmouth, Norwich,
Holkham, and Lynn, such rocks have not been reached by borings
taken to a deeper level than that at Culford.
It is noteworthy that the range of depth to the older rocks, over
so large a district as that within which the borings occur, varies
only to the extent of about 700 feet, and this is between Culford
and Richmond, a distance of more than 70 miles.
Site of Boring.
Overlying
Formations.
Cretaceous...
Culford (Suffolk)
Ware (Herts.) J Cretaceous...
Cheahunt(Herts.) { I }
Kentish Town f Tertiary... 1
I... \ Cretaceous J
(Middlesex).
Loudon, Meux's
(Middlesex)..
(Kent)
[ Tertiary... ]
i Cretaceous J-
Jurassic ... J
;}
(Sur-
rej)
Harwich (Essex) {
Dow (Kent) ... |
Tertiary
Cretaceous
Tertiary . . .
Cretaceous
Jurassic ...
Tertiary...
Cretaceous
Cretaceous
Jurassic
"}
R.chrnond (Sur- I 1 Crrtnceoui
rey)
Jurassic ...
Nature of
Older Rock.
Doubtful
Silurian
Devonian
Red and 1
Grey Rocks/
Devonian
Red and 1
Grey Rocks J
Red and
Grey Rocks
}
Carboniferous .
Carboniferous .
Red and
Grey Rocks
Below
Ordnance
Datum.
Feet.
528?
♦580?
870
930
*
081
1003
1010
1015
? 1120 or +
1220
From the
Surface..
Feet.
637$
796*
980$
1113$
1066
1008
1120
1029
1157
1237
a J. 0t. 8. No. 199.
2n
Digitized by Google
514 BORINGS AT CULFORD, WINK FIELD, WABE, ETC. [Aug. 1 894*
Discussion.
The President pointed out the importance of the work in which
Mr. Whitaker, one of the Authors, had been engaged for so many
years in recording all borings and well-sinkings, and (as in the
present cases, described by the Authors) adding most valuable
information as to the contours of the ancient underground ridge of
Palaeozoic rocks, on which the Secondary rocks rested unconformable*
over so large an area of the Eastern and South-eastern Counties of
England.
Prof. Boyd Dawkins agreed with Mr. Whitaker in his general
conclusions as to the Palaeozoic floor rising to the north, and pointed
out that the sequence of the Palaeozoic rocks in the London area
and the district to the north was exactly that which may be studied
at the surface in South Wales, Gloucestershire, and Somersetshire.
He further called attention to the fact that the non-discovery of
coal-bearing rocks in this area was not to be taken as proving the
non-existence of coalfields in the London Basin. It merely implies
the existence of a pre-Carboniferous region between Ware and
Streatham, and between Richmond and Erith, analogous to that
which separates the coalfield of South Wales from that of the Forest
of Dean, and from that of Gloucester and North Somerset. The
shale at Culford seemed to him probably of Silurian age, and quite
unlike any Yoredale or other shales belonging to the Carboniferous
period. The shale at the bottom of the Harwich boring is of
Yoredale age, and contains Poteidonia.
Prof. J HDD asked Mr. Whitaker whether he had considered the
evidence supplied by the Northampton borings as to rocks of the
Palaeozoic plateau. We have evidence there of red rocks with Car-
boniferous plants and other fossils, and he was not sure that the
beds occurring at the bottom of the Richmond boring might not be
the same abnormal Carboniferous rocks.
Mr. Toplbt also spoke, and Mr. Whitaker briefly replied.
Digitized by Google
Vol. 50.] THE GLACIAL GEOLOGY OF MOUNT KENYA.
515
33. Contributions to the Geology of British East Africa. —
Part I. The Glacial Geology of Mount Kenya. By J. W.
Gregory, D.Sc, F.G.S. (Head May 23rd, 181)4.)
Contests.
I. Tutroduction aft
TI. The former Ulaeiation 518
III The Nature and Age of the Ulaeiation 520
IV. The Causes of the Ulueiation 522
V. Climasic Conditions during the Period of Maximum Ulueiation ... 527
VI. Summary of Conclusions 5&t
Map of the S.W. slopes of Mouut Kenya 517
I. Introduction.
In the discussion as to the respective merits of the rival theories
concerning the causes of former glaciatiou, tew lines of work seem
likely to yield better results than the study of the originally
greater extension of glaciers in tropical regions. When therefore,
on emerging from the dense forests of the lower slopes of Mount
Kenya, I came upon a series of old moraines, not lu miles from
the Equator and far below the level of the existing glaciers, my
interest was at once aroused in the additional problems presented
for solution.
Mount Kenya is situated in long. 37° 20' E. and lat. 0° 6' S. ; it
rises to the height of approximately 1U,500 feet, and covers an
area of about 700 square miles. It consists in its lower purl of
a huge pile of volcanic ash and debris, with a low gradient, rising
from 72U0 to 10,200 feet, densely eovered with forest an 1 bamboo-
jungle. Above this frown steep craggy slopes of coarso agglome-
rates, ash, and lava, while the whole is surmounted by a rugged
pyramidal peak which is part of the central core of the old volcano.
The central peak is of such excessive steepness that the snow is
scattered irregularly over it, instead of forming a 4 calotte ' or snow-
cap, similar to those on Kibo (the higher summit of Kilima Njaro)
and Chimborazo. The snow accumulates in the hollows and ou
the slopes with lower gradients ; from these snow-tields a series of
glaciers flow down into the valleys.
The existing glaciers occur mainly on the western and south-
western slopes of the mountain. The three principal classes of
glaciers are represented ; there are the normal valley-glaciers, of
which the largest is the Lewis glacier, named after the lato Prof. J.
Carvell Lewis, whose premature death cut short a career of such
brilliant work on glacial geology. This, and two similar valley-
glaciers to the north-west of it, flow from neve-fields to below tho
snow-line. Their lower courses are bordered by moraines. The
glaciers are crevassed, especially in the steeper portions of their
course, and are separated Irom the neve-fields by fairly large benj-
Hchrunils. Tho second type consists of the 1 corrie ' or ' hanging
Q.J.G.S. No. 200. 2o
2o 2
Digitized by Google
518
DR. J. W. GREGORY OH THE
[Nov. 1894,
glaciers' ; the two largest of these are situated on the south-western
face, just north of the south-western arete. They end in vertical
ice-cliffs 200 to 300 feet high. Below these are huge masses of
fallen ice-blocks, by the consolidation of which the third type or
the 4 re-cemented glaciers ' have been formed : these are here tribu-
tary to the valley-glaciers.
The snout of the Lewis glacier ends at the height of 15,580 feet,
but the two others reach a lower level, as they occur in sheltered
valleys and drain larger collecting-grounds : they come down to
about 15,300 feet.
♦
II. The former Glaciatiok.
As has already been remarked, the lower elopes of the mountain
are swathed in so dense a cloak of vegetation that it is impossible, 011
a hasty march through that area, to learn much regarding its
geological structure. At the level of 9800 feet, however, 1 found
some erratics of coarse audesite, some of which measured about
4x4x3 feet. They were much weathered and rounded, but their
surfaces were still grooved ; they were certainly not in W/u, and did
not appear to be ejected blocks. I halted the caravan, and cut my
way through the neighbouring bamboo-jungle, in order to 6ee
whether 1 could obtain any evidence of the former existence of a
parasitic cone at this point. No such evidence, however, could be
found, and the irregularly undulating nature of the ground seemed
to indicate that the rocks are a series of erratics overlying or
weathered out of an old moraine, rather than an extra-morainic
fringe.
As soon as we emerged from the forests, we came on abundant
evidence of former glaciation, for we struck at once ou a terminal
moraine. Hugo erratics lay strewn about, and I soon noted among
them specimens of most of the coarser rocks which were afterwards
found in the central portion of the mountain. Small sections cut
by streams showed that these occurred in a stiff, greasy clay,
formed of a re-deposited volcanic ash : it was of the type familiar
as the matrix of a boulder-clay. The scenery also, with its irregular
undulations, its numerous swampy, mossy hollows, and its scattered
boulders, was highly characteristic of old moraines.
Above the moraino rises a steep, glaciated, rocky slope, over
1000 feet in height, from the summit of which the first view of tho
general structure of the mountain may be obtained. The base is 6een
to consist of a vast forest-covered declivity, rising with a gradient
of about 1 in 18 to the level of 10,L?00 feet. Between the forests
and the base of the rock-slope is the undulating tract of moraine,
which I could now see was continuous as a belt all rouud the
mountain. From the edge of the rock-slope lises a series of alpine
meadows furrowed by deep valleys, the walls of which are crovrned
by picturesque pillars and crags of agglomerate and lava. From
this last /one abruptly towers tho pile of rocks that forms the
great central peak.
The rock-slope cau be clearly seen from Laikipia, and is shown
Digitized by Google
Vol. 50.]
GLACIAL GEOLOGY OF MOUNT KENYA.
519
in von Hohnels sketch from Ndoro ; its nature appeared to mo rather
puzzling, as there were points in it which did not accord with the
theory of its heing a crater-wall. Its moutonne surface, however,
showed that it had heen groatly worn by glaciers, and it doubtloss
represents the site of the old ice-fall that once occurred here when
an ice-cap covered the upper part of the mountain.
In the whole of the alpine zone of Mount Kenya there is abundant
evidenco of former glaciation. The rocks on the face of the rock-
slope, the bosses that rise from the peat-swamp above it or are
exposed on the flanks of the valleys, are all moutonnees. Erratics
and perched blocks are numerous on the sides of the valleys and
even on the summits of the ridges that separate them. Three
final proofs were the discovery in the higher parts of the valleys
of glaciated lake-basins, of a series of terminal moraines, and finally
of well-preserved strire. It is, I think, desirable to describe ex-
amples of each of these in detail, so that the foregoing statements
may be the more readily checked by future visitors to the mountain.
(1) Lake-Basins. — The example of these which best shows a
glacial origin is that which I have named Lake Hohnel (soe fig. 3).
Fig. 3. — Section through the cirque, on tlie W. side of Mount
Hohnel, and its lake-basin.
[Natural scale: \ inch = I mile.]
Mt Hdhnel
It is situated in a cirque on the western face of Mount Hohnel, and
has its longer diameter running north and south. Between the base
of the cliffs of the cirque and the lake is a swampy plain formed by
the tumbling of talus from the crags above. The lake is nevertheless
at its deepest near the eastern shore, and apparently shallows gradu-
ally to the west. On this side it is bounded by a bare rocky barrier,
the whole of which is moutonnSey while some enormous andesite
erratics are perched upon it, in positions which they could not
possibly have held unless transported by glaciers. For the sake
of avoiding unnecessarily controversial topics, it may be advisable
to leave untouched the subject of the possible glacial origin of cirques,
although the alternative theory of waterfall action is clearly inap-
plicable here. I do not think that anyone could contest the glacial
520
DR. J. W. GREGORY ON THB
[Nov. 1894,
origin of this lake-basin, unless he were ready to adopt the
extreme position of denying the glacial erosion of any of the small
Alpine tarns and lakelets ; and this is admitted by many of those
who are most resolutely opposed to such a theory of formation for
the greater lakes of Switzerland aud Scandinavia, and the lochs
and fiords of North- western Europe.
(2) Old Moraines.— Of the numerous moraines connected with
the present glaciers, a group in the upper part of the Tcleki Valley
serves as the best example ; I have never seen any old set of moraines
preserved with more diagrammatic simplicity than these. The firat
three stand out from the north wall of the valley as clearly as so
many railway-embankments. They are composed simply of piles
of andesite-boulders, with a smaller proportion of clay than is usual
in Alpine moraines. They are about 30 feet in height and reach
nearly across the valley. A small tarn occurs behind the upper-
most one, and the drainage from this — as well as the stream that
flows from the glaciers — is forced by the moraines to the south
side. A little farther up, the valley bends abruptly northward,
and is crossed by a steep rock-slope that doubtless marks the site
of an old ice-fall. From this point a median moraine runs along
the valley, and marks the line of junction of the Lewis glacier with
that which flowed from the other two.
The Map which accompanies the present paper (fig. 2, p. 517)
shows the general arrangement of this group of moraines.
(3) Stria!.— The rocks ou Mount Kenya are for the greater part
coarsely crystalline lavas which weather irregularly and rapidly,
and would do so even if they were not subjected to such exception-
ally powerful disintegrating agencies as those which operate on the
summit of Kenya. I did not therefore expect to find striae on
unexposed surfaces. A few lik<*ly situations on lava-bosses on the
sides of the valleys were selected and the turf removed: strire
were then found in every case ; they were usually very well marked,
and especially so on the rocks near the great bend of the Teleki
Valley, at the point marked in the map (fig. 2, p. 517). The other
localities are not marked, as the striae were there not so well pre-
served and might easily be overlooked by anyone who was not
prepared for a little trouble and had not had some practice iu
observing striaa.
The boulders in the upper moraines are seldom striated.
III. The Nature and Age op the Glaciation.
In the preceding pages evidence has been adduced to prove that
the existing glaciers on Kenya wore once far more extensive than
they are at present. They are now merely 4 stream-glaciers.'
Erratics, however, occur on the crests of the ridges, as on that on
the north side of the Teleki Valley ; the ice must therefore at one
time have completely filled up the valleys, as they were then in
existence. Moreover, the great terminal moraine which probably
extends all round the mountain could not have been formed by any
Digitized by Google
Vol. so.]
GLACIAL GEOLOGY OF MOUNT KENYA.
521
system of mere valley-glaciers, as the moraine occurs in places at
the foot of a rock-slope which is concentric with the peak and at
some distance from the mouths of the radial valleys. This terminal
moraine could alone have been formed by an ice-sheet which filled
up the whole of the valleys then in existence and spread out over
the whole surface of the mountain as a * calotte/ The ice-cap
would huve been much like that which now fills up the crater of
Kibo, or that which Mr. Whymper has so well described as covering
the dome of Chimborazo, or again that which the Rev. Maxwell Close
has invoked to explain the glacial phenomena of Iar-Connemara.1
It must bo remembered, therefore, in studying the glacial evidence
near its lowest margin, that we have to deal with an ice-sheet and
not with a mere valley -glaciation.
Formtr Extent. — The glaciers now terminate at a height varying
from 15,300-15,580 feet, or we may take the mean as 15,400 feet.
The old moraine at the foot of the ice-fall occurs at the level of
10,000 feet, while the erratics can be seen down to 9800 feet. How
much farther they extended it will be very difficult to determine,
owing to the denseness of the bamboo-jungle that covers this region
of the mountain. The glaciers, however, unquestionably extended
for at least 5400 feet below their present limit.
Aye of the Glaciation. — This is another problem that can only be
approximately determined. The upper set of moraines in the
Teleki Valley are very perfectly preserved, but there are full-sized
specimens of the arborescent Lobtlia gregoriana, Baker til., and
Senecio kenytnsti. Baker fil., growing upon them. Though the
former of these may reach the height of 25-30 feet, they are pro-
bably of very rapid growth. The great terminal moraine is certainly
much older ; it is weathered, the slopes are rounded, gullies and
valleys have been cut through it and the sides covered with turf ;
the boulders are covered with moss and the stria? have been erased ;
the roches mouto antes have lost their polished surfaces, and only
the deeper grooves and the general form remain to attest their true
origin. Great trees, whose age must be measured by centuries,
grow in sheltered places on the moraine.
There can be no reasonable doubt that the glaciation took place
at a date which, judging by historical standards, must have been very
far distant ; it was probably anterior to the introduction of the
tribes who now inhabit the district, and may date back to the
period of the maximum extension of the lakes of the East African
lake-chain, of which the present members are the greatly diminished
representatives.
In reference to the age, it may be asked whether the glaciers
are now still receding. Fig. 4 (p. 522) shows the snout of the Lewis
glacier encircled by a set of terminal moraines ; the uppermost of
these, however, has been burst through by the glaciw" ,and therefore it
has recently advanced. The advance, however, has bo far been a very
1 G. H. Kinnhno and Maxwell H. Clone, ' The General Glaciauon of Iar-
Conneinara.' Dublin, 1872, p. 18.
Digitized by Google i
522 DR. J. W. GREGORY 05 THE [HOT. 1 894,
Fig. 4. — Terminal Moraines of Oie Lewis Glacier. (Diagrammatic.)
small one, and the close proximity of the different memhcrs of this
series suggests that the glacier has been for BOOM time almost
stationary, but. subjected to numerous slight oscillations. These
may result from irregular annual variations in the snowfall, but it
is not improbable that they may have been produced by the well-
known oscillation of the ice-periods 1 which results from the period-
ical oscillation iu the temperature of the globe.
IV. The Caises of tiie Glaciation.
The main geological intorcst of the former extension of the
Kenyan glueiers, at a period geologically recent, is the fact that the
1 M. Rykfttuchew. * l"eber den Auf- und Ztigang dcrGpwawr des ru»»isrhen
R*iehe».' II1" Suppl. Bd. zum Kepert. f. Meteor. St. Petersburg, 1887, p. .r»3.
Ed. Bruckner, ' Kliiuasehwankungen seit 171M). nebst Bomerknngen iiber die
Kliiiuuk'hwnnkungen der Diluviolzeit,' Geogr. Abh. vol. if. lleft 2 (1890),
pp. 'J44-J55.
Google
"Vol. 50.]
GLACIAL GEOLOGY OF MOUNT KENYA.
523
mountain is situated directly on the Equator. Bearing in mind that
the glaciation of Northern and Central Europe, North America, and
New Zealand took place in times which are geologically approximately
synchronous, the discovery of a great extension of the Equatorial
glaciers seems at first sight to supiKjrt the idea of the universal re-
frigeration of the globe and to necessitate some astronomical expla-
nation of its cause.
Theories of the universality of glaciation aro here ignored because
of the absence not only of any traces of former more extensive
glaciation from the tropics, as in the Andes and K ilium Njaro, but
also from the Cape.
The absence of evidence in the first of these three is very striking.
In spite of the extensive glaciers now in existence on the higher
peaks of the Andes, there is practically no evidence of their
former greater extension. Mr. Whymper kindly tells me that only
in two cases did he see any traces of glaciation below the limits of
the present glaciers ; the chief of these were some decayed rochet
below his second camp on Chimborazo, but it was only a little below
the level of the neighbouring Glacier dc Debris.
Nor has any such evidence been recorded from Kilima Njaro,
though over 100 Europeans have visited it. The majority of these,
however, have been sportsmen or naturalists with no geological
training, and the others have not reached the level which the glaciation
attained. Both Hans Meyer 1 and L. Purtscheller are well acquainted
with the appearance of recent glacial phenomena, but it is possible that
they may have failed to recognize the weathered traces of old
moraines. Some doubt may therefore be felt as to the negative
evidence in this ease.
Another negative record is that of Prof. Henry Drummond, who
says, 44 In East Central Africa not a vestige of boulder-clay, nor
moraine matter, nor striaD, nor glaciated surface nor outline is
anywhere traceable ; " and he adds 44 It has been my lot to have
had exceptional opportunities of studying the phenomena of
glaciation." 1
The third case is the most instructive. The one region of Africa
that one would expect to have been glaciated, if any were, is
Cape Colony : but it seems almost certain that, in spite of some old
records, this district cannot have been glaciated since at least
Cretaceous times, for otherwise erratics of the conspicuous 4 Pipe-
Amygdaloids ' of the Stormberg series must have been carried on to
the surrounding lowlands.
It docs not therefore seem necessary to consider here the theory
that explains glaciation as being due to the alteration of the position
of the earth's axis of rotation, notwithstanding the remarkable astro-
nomical results recently obtained, which show that some shifting of
1 Meyer speake of moraine-like ridge* round the mow- fields, but explains
th«»m as merely talus accumulations ( 'Across £ast African Glaciers,' pp. 312-
313).
a 'Tropical Africa/ 4th edit. 1891, p. 198.
Digitized by Google
524
DR. J. W. OEEQOET OK THE
[Nov. 1894,
the pole almost certainly does take place. As this, however, is period-
ical and of very slight amount, its effects would be insignificant.1
Another favourite theory— the agency of a different distribution
of land and water — cannot be applied in this case, unless one is
prepared to maintain the existence of Gondwanaland to a very late
Tertiary date, which probably few geologists would be prepared
to do.
It seems therefore necessary to fall back on a purely local explana-
tion, of which tho natural one is elevation, owing to which a greater
mass of the mountain was upreared above the snow-line. This
elevation may have been effected by either or all of the three follow-
ing agencies : —
(1) An elevation of the whole region.
(2) Local earth-movements of the Mount Kenya district.
(3) By the height of the volcano before it was reduced to its
present level by denudation.
In regard to tho first, there seems no sufficient evidence to establish
the existence of any subsidence of the country for oUOO feet. The
fiord-like estuaries that run up into the coastal plain, such as Port
Reitz, or the harbours of Kiliudini, Takaaungu, or Khiliti, indicate a
submergence of only slight amount. The coral-reefs of the coastal
plain show changes of level all along the coast which vary in amount
from 20 to 50 feet.
There may be evidence of a greater and older submergence in the
occurrence of some limestones on the Magarini Hills, though it is
probable that the rocks have been carried there (for some economic
purpose) by some exceptionally energetic native. But even if they
be in placo, they indicate a subsidence of only some 300 feet, which
would be quite useless.
It may be suggested that the depression, which formed the chaunel
of over 1000 fathoms in depth that broke the former connexion
between Madagascar and the mainland, indicates a subsidence of the
whole region of the required amount. But the differences in the
fauna and flora show that this was probably much older than the
period of maximum glaciation, while tho subsidence along this line
is more likely to have counterbalanced a simultaneous elevation of the
1 The principal references to the subject of the variation of latitude are aa
follows : —
S. C. Chandler: six papers in Astron. Joura. Not. 248-251, 267, 277, and
Monthly Notices R. Astron. Soo. vol. liii. (1893) pp. 119-120. For subsequent
discussion, see F. Folie, 'Ensai sur les Variations de Latitude, ' Bull. .Acad. R.
Soi. Brux. se>. 3, vol. xxvi. (1893) pp. 577-613 ; A. d'Abbadie. • La Fluctuation
des Latitudes terrestres,' Bull. Astron. vol. ix. (1892) pp. 89-102; Simon New-
comb, 'On the Dynamics of the Earth's Rotation with respect to the Periodic
Variations of Latitude,' Monthly Notices R. Astron. Soc. toI. lii. (1892) pp. 33ti-
341 ; H. G. Tan de S. Bakhuvzen, * Variations of Latitude deduced from the
Obserrations of Polaris inacle at Greenwich 1851-89,' op. tit. toI. Ii. (1891)
pp. 286-306 ; W. G. Thaokeray and H. H. Turner, ' On the Variations of Lati-
tude as indicated by Recent Observations at the Royal Observatory, Greenwich,'
op. eit. toI. liii. (1893) pp. 2-11 ; W. G. Thackeray, • Latitude Variation and
Greenwich Observations 1851-1891,' ibid. pp. 120-123, pis. iii.-v., and ibid.
J p. 292-296 ; G. C. Comstock, • The Secular Variation of Latitude," Amer.
oura. Sri. ser. iii. toL xlii. (1891) pp. 470-482.
Digitized by Google
Vol. 50.]
GLACIAL OEOLOOT OF MOUNT KENYA.
525
land-masses on either bide than to hare been part of a widespread
equal earth-movement.
There is therefore no evidence on tho coast of changes of level
sufficiently recent or important to account for the glaciation.
The second suggestion, namely, that it was due to local earth-
movements, seems much more probable, as in the great rift- valley a
few miles to the west there is evidence of very extensive faulting
and earth-movements of Pleistocene age ; some of these have cut
through the great pile of Settiraa, the companion volcano that rose
opposite Kenya on the western side of the Laikipia plateau. If
there were no elevation on the coast or at Kilima Njaro, a differential
movement of only 1 in 250 would give the required elevation on
Kenya.
The third cause no doubt contributed something, as not only must
the cone once have been very much higher than it is at present, but
the slopes would then have beeumore suitable for collecting snow than
the precipitous crags that now form the central summit of the
mountain. It is unfortunately impossible to determine from the
data at present available the exact height of the original crater, as,
until it is known how much the forest-clad slopes have been lowerod
by denudation, one cannot estimate the height and extent of the
base from which the crater rose. Kibo rises about 2000 feet higher
than Mawenzi, and the parallel between these, tho newer and older
eruptive centres of Kilima Njaro, must be very similar to that
bet ween Kibo and Kenya. If we assume that the slopes of Kenya
in its prime were at the same angle as those of Kibo, then an
addition of 2000 feet to the altitude of Kenya would form a peak
of almost exactly the right diameter.
We may thus account for 2000 of the 5400 feet required. But
an increase in the size of the snow-fields would lead to an iucreaso
in the length of the glaciers, which would thus reach a lower level.
To take an illustrative case from the Swiss glaciers. The following
glaciers are arranged in pairs, and the members of each pair are
closely adjacent and under apparently similar conditions ; thus the
two Grindelwald glaciers are parallel, adjacent, flow from the same
mountain-axis, and both to the north; the Aletsch and Fiesch
glaciers are also similar, but flow both to the south. The figures
are taken from Heim's * Handbuch der Uletscherkunde,' p. 73 : —
Same of Glacier.
field in tquare
of glacier in
below the new
kilometre*.
metres.
line in metre*.
69
1840
9(>0
27
2100
650
Area of
collecting-
ground.
fAletacb
99-64
1353
14IK)
33-57
1500
1300
22-0
1879
850
67
500
Unter Grindelwald. . .
28
1080
1650
Ober Grindelwald ...
12
1320
1400
526
Dtt. J. W. GREGORY ON THE
[Nov. 1894,
This shows that in each case the glacier with the larger collecting-
area goes the lower and farther below the neve-line. The distance
to which this 2000-feet addition to the height of Kenya would carry
down the glaciers cannot be determined ; it would depend (1) on the
rote of the motion of the glaciers, which is probably high — owing to
the steepness of the gradient and the enormous diurnal range of
temperature : I had intended to measure this, but the refusal of my
men to approach the snow-line rendered it impossible to do so ; and
(2) on the rate of ablation, which would probably be very great aud
would lessen the length of the glaciers.
The fact, moreover, that the valleys are glaciated to their bottoms
and that perched blocks still surmount the crests show that there
has been no very great denudation in the alpine zone since the
maximum glaciation. Thus, though there may have been a consider-
able lowering of the central plug which now forms the summit since
the time of maximum glaciation, in the later stages, as when the
glaciers were depositing the terminal moraines of the Teleki Valley,
the entire crater-walls had disappeared. Therefore, though the
lowering of the summit by denudation has no doubt helped to restrict
the downward extension of the glaciers, as these were more extensive
in times later than the destruction of the crater, this factor can
account for only a fraction of the balance of 3400 feet.
In spite, however, of the absence of evidenco of earth-movements
on the coast or of a glaciation of Kilima Njaro, there is one line of
argument which shows that the elevation was not limited absolutely
to the Kenya district. On the higher summits of Kilima Njaro,
Ruwenzori, Elgon, the mountains of Abyssinia and the Cameroons,
there is an alpine flora quite unlike anything in the lower country
of Equatorial Africa. This must once have extended across the
lower plateaux and retreated to the mountains as the land subsided
to a warmer and lower level. In the 'Geographical Journal' 'is
a map illustrating the present and former distribution of this alpine
flora, showing that a downward extension of the glaciers for a
little over 5000 feet would enable this distribution to bo effected
without the intervention of any universal African ice age, and merely
as a result of its greater elevation. The fact that the fauna extended
to the Cameroons is of interest, as the submerged fiord beyond the
mouth of the Congo shows that great subsidence has occurred in
that region.*
1 J. W. Gregory, « Contributions to the Physical Geography of British East
Africa,' 1894, vol. iv. p. 289.
3 Enrico Staseano, ' La foce del Congo/ Atti R. Aocad. Lincei, ser. 4, vol. ii.
pt. 1 (1886), pp. 510-613 ; tee alio Ernst Linbardt, ' Ueber unterseeische Fluss-
rinneu,' Jahresber. Geogr. Gesellach. Miinchen [1890-91], 1892, pp. 26-27,
41-42. It is fair to note, however, that this caw is not regarded as a proof of
subsidence by J. Y. Buchanan, • On the Land Slopes separating Continents and
Ocean Basins, especially those on the West Coast of Africa,' Scottish Geogr.
Mag. vol. iii. (1887) pp. 222-223.
Digitized by Google
Vol. 50.]
GLACIAL GEOLOGY OF MOUNT KENTA.
527
Y. Climatic Conditions during the Period op Maximum
Glaciation.
The former distribution of the alpine flora of Equatorial Africa
is an indication of the different climatic conditions that resulted
from or were concomitant with the maximum glaciation. An
attempt will bo made in this part of the paper to determine the
meteorological conditions of Equatorial Africa at that periud.
In the first place, it will be advisable to consider the changes in
the general conditions of the atmospheric circulation, that would
have resulted from the elevation of Mount Kenya for over 5000
feet, and then the effects of these changes on the atmospheric
pressure and thus on the winds and rains.
The first change to be noticed is that the whole of the uplifted
region would be colder. The averago rate of decrease is generally
taken, following Herschel, at 1° F. for every 300 feet of ascent;
and though in many later cases which have been more accurately
observed the rate of diminution of temperature has been increased,
it may be advisable to take this rate — so as not to exaggerate the
amount. But it must bo remembered that the rate of cooling
increases both with the ascent and the seasonal descent of the
isotherms. The annual mean, however, for the carefully collected
data given by Hann 1 from the observations on the Theodule, when
reduced to feet and Fahrenheit, also gives 1° F. for 300 feet. As
these results were obtained at the height of over 10,000 feet, and
well above the snow-line, tho conditions of that case are probably
fairly analogous to those on the higher African peaks.
The mean temperature will therefore have been 17° F. lower
thau at present. This would have a treble influence: (1) the air
would contract in bulk ; (2) the saturation-point would be lowered,
and the air become drier ; (3) there would therefore, owing to the
increased precipitation, be more snow than under existing conditions.
Now all these throe factors tend in the samo direction, viz. an in-
crease of barometric pressure on the lower regions and a depression
of the isobaric surfaces. Consequently, there would be at night, when
the cold is greatest, an inset current at a high level toward the
mountain. This further helps the depression of the isobaric
surfaces, and there would thus be at night a downrush of air
along the slopes, similar to that well known in the Alps, with a
high-level inset current sweeping in to the mountain and carrying
the damp air from the surrounding lowlands on to the snowclad
summit.
In the daytime the conditions would be reversed ; the sun would
exercise enormous power, the surface of tho mountain would bo
heated, ablation would be very rapid, the air would become moist, the
1 J. Hann. ' Ueher das Klima der hochsten Alpenregionen,' Zeitsohr.
oes'terrfich. Gesellsch. Meteor, vol. v. (1870) p. 1U7.
See also Hann's recent memoir, 'Weitere Untcrsucbungen iiber die taglieho
Oscillation des liaroinetera,' Uenkschr. k. Akad. Wissensch. VVion, vol. In. (18'J2)
Pi,. 207-aoO.
Digitized by Google
528
DR. J. W. GREGORY ON THE
[Nov. 1894,
isobaric surfaces would rise and air rush in from below. There
would thus be a high-level radial outflow, and a low-level inflow.
The air would not, however, be free to move radially from the
mountain equally in all directions, for along the Equator there is a
prevailing westerly wind. This is due to two factors: as the heated
air rises, if its proper easterly motion were to remain the same, its
radius vector would increase; its velocity has therefore, by Newton's
second law, to diminish, and it lags behind as a westerly wind.
Then the air that rushes in to the Equator from north and south
has a lower eastward velocity than points on the lower latitude ; it
therefore also drags to the west. Therefore any low-pressure area
on the Equator is simply in the position of a stationary eddy on a
westward-flowing stream, and is supplied mainly from the east.
Thus L'ganda, as it is in the neighbourhood of the low-pressure
area of the Nyanza, has its prevalent winds from the east. But
east winds in this part of Africa are dry ones, because they arise on
the dry barren steppes or ' Nyika ' between the mountains and the
sea : for the monsoons blow parallel to the coast, and thus cut off
any large wind-supply from the Indian Ocean. The wet winds aro
those from the great forest-regions of the west ; thus it is that the
snow- line is so much lower on the western sides of Kilima Njaroand
Kenya than on the eastern ; in the former, the glaciers reach the level
of 13,800 feet on the western side and only 18,700 on the eastern.
The different amounts of snow on the two sides of the main southern
arete of Kenya show that the same condition holds there.
The points to which these observations have led up are : —
Istly. The meteorological conditions of Kenya and doubtless also of
Kilima Xjaro1 are very different from thoie on the surrounding plains,
for there is a daily reversal of the wind-direction, so that westerly
winds can come in at all times of the year and not only during the
changing of the monsoons. There is therefore no such sharp
differentiation on these mountains into wet and dry seasons.
2udly. If the whole region wero raised 5400 feet, an enormous
tract of country would be placed under these conditions, and not
only a few isolated peaks.
Let us next consider what influenco would result therefrom on the
conditions of atmospheric circulation, and thus on the rains and
plant-distribution.
At the preseut time this region of Africa appears to be one of low
pressure. If we take Dr. Buchan's isobaric charts for each month
and calculate from these the mean for 5 points — viz. tho north end
of Lake Nvassa, Zanzibar, the first point at which the Congo crosses
the Equator, the Nyanza, and Khartum — we get indications that the
low-pressure area of Arabia and the Sahara has a branch up the
Nile Valley to the south. This is shown in fig. 5. In the time of
1 liana Meyer has discussed (' Across East African Glaciers,' pp. 307-310) the
winds of Kilima Njaro, which are not now under the same conditions as those
of Kenya, for it is over 200 miles south of the Equator, and therefore is within
the region of the trade winds, and not of the Equatorial westerly drift. It is,
moreover, nearer the southern line of maximum pressure.
Vol. 50.] GLACIAL OEOLOGT OF MOT7JTT XEKYA. 529
Fig. 5. — Isobaric Map, showing the low-pressure area in
Equatorial Africa.
The dotted line* = mean isobars.
the maximum glaeiation, on the other hand, a high-pressure area
would have occurred over Kenya, Kilima Njaro, Elgon, and doubtless
also the Ruwenzori districts ; this would have resulted from the cold,
dryness of the air, abundance of snow, and inset high-level current.
The influence of this on the rains would be as follows : —
(1) This high-pressure area would deflect the normal westerly
drift of the air along the Equator, and therefore more air would
reach this region from the damp forest-land of the west than does
so at present.
(2) The whole region, moreover, would be subject to daily reversal
of the direction of the wind, and thus there would be much greater
local irregularities, and no sharp differentiation into wet and dry
seasons. The rainy seasons are now very well defined on the low-
lands. They occur : —
On the coast at Lamn, Mombasa, etc., from April to August and
for parts of December and January.
In South-western Kikuyu from February to May.
In Uganda from September to November and in April.
Around Basso Narok (Lake Kudolph) in April and May.
In Southern Abyssinia in March and April.
(3) The maximum rainfall now occurs in the forest zone on Mount
Kenya, between 7000 and 11,000 feet, though at some seasons it
may rise higher, just as in the Alps it is in the winter at from
3000 to 4000 feet, and in the summer occurs above the highest peaks.1
But when the ground was higher the line of maximum rainfall
would not rise to the same amount, owing to the resultant lowering
1 J. ITann, ' Die jahrliche Periode dee Regenfalles in Oesterrcich Ungarn,
ZeiUchr. oesterreich. Gesellsch, Meteor, vol. xv. (1880) p. 204.
Digitized by Google
530
THE GLACIAL GEOLOGY OF MOUNT KENYA
[Nov. 1894,
of the temperature. At the period of maximum glaciation it would
therefore occur relatively lower than at present, and there would
thus be a considerable rainfall over areas that are now very sparbely
watered.
The result* on the rainfall of the changes that would have
occurred at the time of the maximum glaciation would therefore
have been : — (1) an increase in its amount; (2) a relativo lowering,
and therefore widening, of the surface of maximum rainfall; (3) the
more even distribution of the rain throughout the year.
The results on the vegetation of the district would have been very
great. Much of the scrub which now covers the country with its
spine-like or narrow leaves, and succulent leafless herbs and trees,
which are all specialized to secure a minimum of transpiration,
would have been replaced by vegetation of a more normal and
luxuriant growth, and better adapted for animal food. The forests
that now occur as belts beside the rivers would have spread out as
wide tracts of primeval forest, similar to those of the Congo and
the Aruwimi, which are now limited to the western side of the
Tanganyika rift-valley. Hence in the time of maximum glaciation
the food-supply for insects and small mammals would have been
distributed very differently from what it is at present, and there
would have been fewer, if any, of the waterless wastes that now
present barriers to animal migration.
VI. Summary of Conclusions.
1. That, by the discovery of moraines, stria?, glacial lake-basins,
perched blocks, and roches moutonntts below the present
limit of the Kenyan glaciers, it is proved that these must
ouce have extended lor at least 04UU feet below their
present level.
2. That at the time of maximum glaciation Mount Kenya was
covered by a great ice-cap or 4 calotte/ and did not merely
support a system of valley-glaciers.
3. That the glaciation was due to the former greater elevation of
Mount Kenya, which has been reduced by subsidence and
denudation. The theory of an universal glaciation is un-
necessary, and is opposed by many facts in African geology.
4. That the glaciation affected the adjoining mountains, including
Kiliuia Njaro, lluwenzori, Klgon, and Abyssinia, is rendered
highly probable by the facts of botanical distribution.
5. That the meteorological changes concomitant with the maximum
glaciation, and also due to the elevation, would have been
the formation of a high-pressure area and an increase in the
umouutof the rainfall, its more equable seasonal distribution,
and a lowering and widening of the surface of maximum
rainfall.
6. This would have led to a great change in the distribution of
auimal- and plant-life.
Digitized by Google
Vol. 50.]
STRATIGRAPHY OF THE LIBYAN DESERT.
531
34. (hi the Stratigraphy and Physiography of Oie Libyan Desert
of Egypt. By Capt. H. G. Lyons, R.E., F.G.S. (Read
May 23rd, 1894.)
[Plate XXI. — Map.]
Contents.
I. General Description
II. The Nubian Sandstone
III. The CretaceouB and Eocene Strata
IV. The Miocene and Pliocene Strata
- V. The Anticlinal Folds, and their Relation to the Water-supply
VI. The Erosion of the Nile Valley, etc.
VII. The Origin of the Silicifled Wood
I. General Description.
The work of Geheimrath Karl A. von Zittel,1 as a member of the
Rohlfs Expedition of 1874, has furnished us with an accurate
geological description of the western oases of Egypt, which wo can
use as a starting-point for the further exploration of the Libyan
Desert to the north and south of them, and his detailed sections and
lists of fossils are of invaluable assistance in correlating the strata
met with in various parts of this area.
Still, I cannot find that much has been dono since Dr. Zittel's
work except by Dr. Schweinfurth, Sir J. W. Dawson, Prof. Hull,
Prof. Walther, Prof. Mayer-Eymar, and Mr. E. A. Floyer in the
Favum, the Nile Valley, and various parts of the eastern desert,
while the western desert seems to have remained almost unexplored.
In December 18JKJ and January 1894, when on a patrol visiting
the oases of Kharga and Dakhla, and the desert routes to the south
of them, I had opportunities of making a few observations in this
portion of the desort which are, I venture to think, of some interest.
These I have more recently (April 1894) been able to amplify by a
ride through the more northern part of this western dosert, the
route followed being from the pyramids of Giza to Der Macarius,
the easternmost monaster}- in the Wadi Natrun or the Valley of
the Natron Lakes ; thence along the valley some 20 miles to Ddr
Baramus, tho westernmost of the four Coptic monasteries. From
this point I turned S.S.W. and went as directly as possible to the
northern end of the Baharia Oasis, thus traversing an area shown
as geologically unknown in Dr. ZittePs a map. From this oasis I
returned to tho Nile by almost the same road as that traversed by
Prof. Ascherson 3 in 1876.
South of the oases of Kharga and Dakhla, the part of the desert
traversed is included between two lines, each about 100 miles long,
drawn southward from these oases and following the old trade
1 4 Pttlajontographica,' vol xxx. (1888) p. 1.
a Ibid. map.
3 Mitth. geogr. Oesellech. in Hamburg, 1876-77.
a J. G. S. No. 200. 2 p
Digitized by Google
Pape
531
. r»3s
. 534
635
537
541
545
532 CAPT. H. G. LY056 05 THE STRATIGRAPHY AiSD [NOV. 1894,
routes known as the Arbain road and the Terfau road. Between
these two roads the intervening desert was crossed in two directions,
and was found to be a sandstone plateau, falling slightly towards
the north as it ncared the Cretaceo-Eocene limestone-escarpment of
the oases.
Nowhere were any hills of a greater height than 200 to 250 foot
above the plain to be seen, though at a distance, when exag-
gerated by mirage, and especially when on the 6ky-line, small
hillocks appeared to be high hills several miles distant, and
Dr. Schweinfurth, in his map of the Kharga Oasis, records such high
hills in the desert to the south-west.
Speaking generally, the Eocene beds stretch away northwards -
from the line of the southern oases, where they end in an escarp-
ment facing south, until they pass under the Jebel Ahmar 8andstone
to the north of the Baharia Oasis, and under the Miocene beds to the
N.W. in the neighbourhood of the Siwa Oasis. These Eocene rocks
are underlain by Upper Cretaceous rocks, which form the floors of
the oases of Kharga, Dakhla, and Farafra, and the bases of the cliffs
which hem them in on their eastern, northern, and north-western
sides ; while to the south and south-west the ground rises gently
to the Desert plateau, consisting of the Nubian Sandstone, which
forms an immense tableland, rising and falling with gentle slopes,
hardly ever forming hills of any considerable height, but weathering
into flat-topped masses and truncated pyramids, which stand out as
witnesses of the amount of erosion which has taken place. These
isolated hills 1 are a special feature of the Libyan Desert, and
contrast strikingly with the sharp peaks occurring in the crystalline
areas, and with the rounded granite hills formed sometimes of
enormous boulders split off by the variations of temperature to
which they have been subject, and now crumbling away through
the breaking-up of their constituent minerals by the same agency.
The earliest rocks occurring in this area are the crystalline rocks
exposed at the First and Second Cataracts and at Kalabsha(lat. 23°
30' N.), which have been frequently described 2 and have been classed
as Archaean. The only exposures that I know of in this part of the
western desert are, one at the small hill of Jebel Abu Bayan, 10 miles
south of the Eharga Oasis, and the other south of the Dungul
springs, and between them and the village of Tomas, on the Nile, a
few miles above Korosko. This latter spot I have not visited, but
at Jebel Abu Bayan the rock is a coarse-grained hornblendic granite,
with large crystals of pink orthoclase, and is apparently identical
with that described by Prof. Bonney.3 The hill also contains dykes
of a fine-grained granitic rock, and somo of a diorite, as well as one
of a fine-grained basalt.
1 Zittel, • Paheontograpliica,' vol. xxx. (1883) p. 38 , Walther, « Die Denu-
dation in der Wuste,' p. 64, Leipzig, 1891, sep. cop., & Abb. d. k. sacbs. Geeellsch.
d. Wiaeensch. vol. xvi. pp. 407 et teqq.
3 Sir J. W. Dawson, Geol. Mag. 1884, pp. 289, 385, etc.; T. G. Bonney,
Geol. Mag. 1886, p. 103 ; 0. A Bawin, Geol. Mag. 1893, p. 436.
• GeoL Mag. 1886, p. 105.
Digitized by Google
Vol. 50.]
I'HYSIOGRArH Y OF THE LIBYAN DKSKRT.
533
II. The Nubian Sandstone.
Wherever the junction can he seen these rocks are overlain by
the Nubian Sandstone, which becomes coarser at its base, usually
forming a quartz-conglomerate. In no case have I ever observed any
sign of the mctamorphism of the sandstone by the granite as
recorded by Mr. E. A. Eloyer 1 and Johnson Pasha.51 I have not seen
the localities referred to by them, but such metaraorphism is
totally at variance with the mode of occurrence of these rocks in
the area that I have examined. The only case of an alteration of the
sandstone which I have met with is at Jebel Burka, 20 miles
W.N.W. of Wadi Haifa, where a mass of olivino-dolerito has
forced its way through the sandstone, porcellanizing and altering
it for a few inches at the junction.
The Nubian Sandstone varies much in colour and durability,
according to the amount of staining by oxides of iron and
manganese and the amount of cementing silica. Lenticular beds
of clay occur which sometimes extend for several miles, and those
are considerably developed at the base of the hills east of Wadi
Haifa (lat. 21° 55'), while on tho western bank of the river at this
point a bed of stiff blue clay may be seen in some ancient Egyptian
tombs. A similar clay has been recorded as occurring at the Shebb
wells, 100 miles W.N.W. , and I saw a sample of stiff blue clay
brought up from a depth of about lb'O feet from tho surface at the
village of Mushia in tho Dakhla Oasis, where it underlay the water-
bearing sandstone. I am not, however, in a position to bring
forward evidence of a continuous stratum of this blue clay extending
over a large area, and serving to hold up the water in the overlying
beds, though Mr. E. A. Floyer 3 describes it as continuous over a
large tract, and overlying the granite floor on tho east side of the
Nile between lat. 23° and 25° N.
These beds seem to be lenticular deposits rather than continuous
beds, and tho appearance of tho Nubian Sandstone, wherever I
have seen it, is strongly suggestive of an cstuarine deposit. The
strata are often strongly false-bedded, and fine clay-partings occur
from time to time. Nodules* of peroxidos of iron and manganese
are very widely distributed, especially in the portion containing the
fossil trees (Araucarioxylon and Nuolia), and owing to their black
colour, metallic ring, and fantastic shapes these nodules have been
constantly described by travellers as lava, volcanic bombs, etc. A
small hill, Jebel Karan, at the southern end of the Kharga Oasis
has been mapped as a ' black basalt hill/ whereas it is nothing but
a small sandstono knoll that has its sides covered with these nodules,
and with fragments of dark-red sandstone from the bed forming the
top of the hill.
The sandstone itself varies from a dark purplo-red mass of
quartz-grains cemented by silica, coloured by the oxides of iron and
manganese, hard and refractor}', breaking through tho quartz-
1 Quart. Journ. Geol. 80c. vol. xlviii. (1892) p. 577. 3 Ibid. p. 483.
9 Ibid. p. 676. 4 Zittel, op. jam tit. p. 68.
2r 2
634 CAPX. H. O. LYONS OK THE STRATIGRAPHY AND [Nov. 1 894,
grains as readily as through the cement, to a white, soft, friable
sandstone which can be crumbled between the fingers.
In the neighbourhood of Wadi Haifa, and esj)ecially on the eastern
bank, lenticular deposits occur (of 2 to 5 miles and more in length)
of an iron-ore deposit usually strongly oolitic in character ; plant-
remains in the form of fragments of fossil wood occur in it, but no
other fossils, so far as I have been able to discover. These beds are
certainly lagoon deposits formed in secluded pools or backwaters
where marsh vegetation flourished, and the iron deposit was
formed similarly to the bog iron-ore deposits of the Swedish lakes.1
The usual thickness of these beds is about 1£ to 3 feet, and at
Wadi Haifa from two to three of them are exposed in the cliff-
section at various levels.
Prof. Hull 2 considers that the Nubian Sandstone was " de-
posited within the waters of a vast inland lake, occupying the
greater portion of Northern Africa/' but I cannot help thinking
that, so far as Egypt and Nubia arc concerned at all events, it*»
mode of occurrence, lithological character, etc., point to an estuarine
deposit which was gradually invaded by tho Upper Cretaceous sea
as subsidence continued. As I have not been able, in the area I
am describing, to distinguish any one part of the sandstone as being
of different age from the remainder, I shall consider the wholo of
it as being Nubian Sandstone of Cretaceous age, as I believe it to
be, and not as being of Carboniferous 3 age in the lower part. Per-
haps it is only in the eastern parts of Egypt, and in the Sinai
poninsula and Palestine, that true Carboniferous deposits were laid
down.
The better and harder varieties of this sandstone owe their
toughness and durability to the siliceous cement which binds the
quartz-grains together, and usually the darker and more iron-
stained is the sandstone, the more there is of tho cementing silica.
Its origin is no doubt due to the same agency as that which has
replaced the woody structure of the fossil trees, to which I shall refer
again later. The strata are usually almost horizontal, being bent into
very slight anticlinal and synclinal folds, which sometimes extend
over such wide areas as often to render the dip barely noticeable.
III. The Cretaceous and Eocene Strata.
The Upper Cretaceous beds 1 which overlie the Nubian Sandstone
consist of the E.votjyra Overwegi-seTieB, amounting to about 500 feet
of alternating bands of sandstone, clay, shale, and limestone, which
contain a large amount of rock-salt and gypsum disseminated
throughout. Theso are succeeded by green and grey shales, which
are overlain in their turn by a white limestone.
1 Geikie, ' Text-book of Geology,' 3rd ed. 1893, p. 140 ; Roth, « Allgemeine u.
chetnischo Geologic.' vol. t (1879) p. 597 ; vVinchell, 4 Iron Ores of Minnesota,'
Geol. Surv. Minn. Bull. no. 6 (1891) p. 221.
a Trans. Victoria InsL vol. xxiv. (1890) p. 317.
8 Walther, op. jam tit.
« Zittel, op. tit. pp. 61 et tegg.
Digitized by Google
Vol. 50.J
pnrsiooRAPnr of the libtjlx desert
These Cretaceous rocks, making their appearance first in the Nile
Valley near Esna, skirt the Eocene escarpment, of which they form
the base, as far as the oases of Kharga, Dakhla, and Farafra, where
they are exposed over a large area forming the floors of thoso oases.
In the Baharia Oasis. 5 miles N.N.E. of the village of Zubbo, I
found a bed of Evoyyra, examples of which Dr. Zittel has identified
as undersized specimens of Exogyra Overweyi. Thus the sands,
marls, and loam occurring in this oasis are of Upper Cretaceous
age, and members of the Ovtrwegi-series, although they occur here
at most 100 feet below beds of the Upper Mokattam scries.
An outlying mass of the Erogyra Overtvegi-aerics occurs at Bir
Murr, 80 miles south of the Kharga Oasis, and perhaps the limestone 1
recorded as occurring at the Selima Oasis is another outlier of these
beds.
In the neighbourhood of Cairo the Cretaceous beds are brought
up by faults at Abu Roash, 6 miles north of the Giza pyramids
(described by Prof. Walther), and at Jebel Atakka, near Suez. North
of these Upper Cretaceous beds, the Eocene stretch away, forming
the desert plateau, and are divided by Zittel3 into
(a) the Upper Eocene beds.
(b) tho Mokattam series.
(c) the Libyan series.
The lowest of these consists generally of limestone-beds, with
some of a more sandy and marly character, and are characterized
by Operculina libyca and Alveolina. The Mokattam beds consist
of a lower portion of white limestone mainly characterized
by banks of Nummulites (fizensis, and an upper portion of brown-
coloured clay, loam, and sand, with beds of limestone, and banks
of oysters (Ostrea Cloti, 0. cairensis, etc.).
At the north-east and east of the Baharia Oasis the Upper
Mokattam Beds, characterized by Ostrta Fraasi and 0. Cloti (as
kindly determined by Dr. Zittel), occur 30 miles north-east and 20
miles east of Upper Cretaceous beds containing Exoijyru Ovenvegi
in the oasis, and with a difference in altitude of less than 200 feet.
As there is no marked dip of tho beds, we have evidently an overlap
of the remainder of the Cretaceous bods and the Libyan and Lower
Mokattam Beds of the Eocene, and this inference is borne out by
the short distance between the Cretaceous and Miocene outcrops tx>
the west on Dr. Zittel's route to Siwa.
The Upper Eocene rocks have at present only been recognized in
two localities, namely, near the Siwa Oasis and on an island in the
Birket-el-Kurun in the Fayum.
IV. The Miocene and Pliocene Strata.
To the west and north-west this Eocene series passes under
Miocene3 strata in the neighbourhood of the Siwa Oasis, which
1 W. Willcocks, * Report on Perennial Irrigation and Flood Protection for
E^vpt,' Cairo, 18fJ4, App. iii. p. 5.
'J Zittel. op. jam cit. pp. 96 et seqq. 3 Ibid. pp. 128 et $eqq.
Digitized by Google
■530 CAPT. H. O. LYONS ON THE STRATIGRAPHY AND [Nov. 1894,
consist of a series of limestones and calcareous sandstones, and marls
and clays of marine origin, overlain by freshwater beds, also of
Miocene age. These last consist of limestones, and beds of quartzose
sandstones having the grains bound together with a siliceous cement
indistinguishable in hand-specimens from the Jebel Ahraar Sand-
stone. The uppermost freshwater beds are sandy, with layers of
fine-grained ehalccdonio quartz.
The rocks of the Wadi Natruu south of the Natron Lakes are, I
think, of Mioceno age, and possibly of the freshwater series, though
I have not at present any definite evidence to produce on this
point. Lithologically they appear to agree closely with the fresh-
water beds of Siwa as described by Dr. Zittcl, but further exami-
nation of them is necessary.
Marine Miocene beds occur also between Cairo and Suez, at Jebel
<jcneffe and also between Jebel Atakka and Jebel Gallala in
Wadi Baida.
Overlying these Miocene beds of the Wadi Natrun is a sandstone,
usually grey to yellow in colour (though here and there patches
occur of a dark red to almost a black colour, due to oxides of iron
and manganese), moderately fine-grained, of average hardness, and
intensely tough, a toughness due to the siliceous cement binding the
grains. This is the form in which it occurs at Jebel Ahmar, near
Cairo, whence it has often been described.1
In some parts it contains fossil trees (principally Araucario.n/lont
Palmoxylon, Nicolia, etc.a), and the principal localities are the
1 Petrified Forests' 12 miles E. of Cairo, Kum el Khashab (12 miles
W. of the Giza pyramids), and the desert west of the Fayum and
south of the Wadi XatruB, as far as lat. 29° N.
It often happens that the toughest and most durablo sandstone
occurs near large deposits of the fossil trees. Thus Jebel Ahraar is
on the east and Jebel Raibun on the west of the petrified forest
near Cairo ; while at Kum el Khashab, near Giza, the same sandstone
occurs, and 20 miles W.S.W. of Der Baramus, in the Natron Lakes,
I came upon an exposure of this tough, almost black sandstone,
where the desert was covered with numerous fossil trees.
Over all this area we meet with fossil wood in pieces of all sizes,
from small fragments to masses 1 or 2 feet in length, and up to
trunks of 130, 40, and even .50 feet long, and 2 to 3 feet in
diameter, all completely silicificd. These are scattered broadcast
over the surface of the sandstone area, sometimes grouped rather
closely for several miles. They are all lying horizontally in every
direction, half embedded in the sand, the only cases of pieces found
in an upright position being where they had been set up as road-
marks by the Arabs. As the southern limit of the sandstone was
approached trunks grew scarce, and finally only small fragments
occurred for the last 20 miles.
1 Xewbold, Quart. Journ. Geol. Soc. vol. iii. (1848) p. 335; Dawson. Geol.
Mag. 1884. p. 385 ; Schweinfurtb, Teitechr. deutsch. geol. Gesellsch. vol. xxxv.
(18*3) p. 718.
* A. Schenrk, ' Palatograph ica,' vol. xxx. (1883) pt. ii.
Digitized by Google
Vol. 50.]
PHYSIOGIUrilY OF TUK LIBYAN DF.SERT.
537
In goneral appearance, in mode of occurrence, and oven, according
to Dr. Schenck,1 in some of the genera, they are the same as those
occurring in the Nubian Sandstono south of the oases of Kharga
and Dakhla.
Schweinfurth 9 has pointed out that at Mokattam this sandstone
(which may he called the sandstono of Jebel Ahmar,3 where it is
typically developed, and whence it has been frequently described)
lies unconformably on the Eocene beds; A. B. Orlebar * has
described it as resting on Miocene beds in the neighbourhood of the
Middle Station of the old Suez Railway ; I found it overlying the
Miocene beds on the south side of the "Wadi Natrun, while at its
southern margin it overlies a thick bed of Ostre<e (0. Fraasi and
0. Cloti) which is of Upper Eocene (Upper Mokattam) age, thirty
miles north-east of the Baharia Oasis.
A tongue of it, 25 miles broad, crosses the road from the village of
Mandisha (Baharia Oasis) to Bahnessa (lat. in the Nile Valley),
commencing 40 miles from Mandisha, and ending at a point rather
above the banks of Nummulite* gizensis in the Mokattam series.
Thus it seems that this Jebel Ahmar Sandstone is later than the
marine Miocene beds, being perhaps of Upper Miocene age, and it
may be of a not very different age from the freshwater Miocene
beds in the neighbourhood of Siwa, as suggested by Zittel.4 It is
this sandstone which furnishes the quartz-mind of the dunes of this
western part of the Sahara, till we come to the outcrop of the
Nubian Sandstone.
Of later age than these are the beds south of the Giza pyramids,
containing Clypcaster agyptiacus, and the sea-beaches of Cairo, to
which a late Pliocene age has been assigned.
In the oases, and especially in tho southern part of Kharga, there
is a considerable area covered by a fine sandy loam, slightly cal-
careous, unstratified, containing rootlet-tubes and occasionally land-
shells. This is evidently the result of fine sand and dust drifted by
the wind till it was retained and bound together by vegetation,
when the oasis was more cultivated than now. In recent times,
from want of cultivation, the loam has been deeply eroded and
rapidly removed by the wind.*
V. The Anticlinal FoLns, and theib Relation to the
Water-supply.
About 90 miles south of the Kharga Oasis (lat. 23° 20' N.) is the
spring Bir Murr (the bitter well), the first watering-place on the
1 Op. tit. p. 15 : species given in columns 1, 3, 5, and 8 are from this
Jebel Ahmar sandstone.
3 Zeitschr. deutsch. geol. Gesellscb. toI. xxxr. (1883) p. 718.
* This term seems preferable to that of 4 JVtco/w-sandstone,' since that fossil
tree is described as occurring both in these beds and in the Nubian Sandstone.
* Journ. Bombay Branch Boy. Asiat. Stc. vol. ii. (1845) p. 232.
* Op. jam tit. pp. 132, 134.
* See Richthofen, • On the Mode of Origin of Loess.' Geol. Mag. 1882, p. 293.
638 CAPT. H. 0. LYONS ON THE STRATI GRAPH Y AND [NOV. 1894,
Arbain road leading to Dongola and the Sudan, where caravans
water their camels, the water being too Bait for men to drink.
Geologically it lies in a small depression eroded out of the
Cretaceous {Erogyra Overwegi) beds, and is situated on tho crest of
a sharp anticlinal fold.
As this spot furnishes an important clue to the stratigraphy of the
desert, I will describe it somewhat in detail. On approaching the
spring from any direction, attention is at once arrested by a large
bed of white limestone forming a small plateau. The limestone
contains many Cretaceous fossils, and is underlain by a bed of
Exogyra Overwegi. Below this is a series of grey, green, and
yellow beds of sand and clay with two or three bands of a calcareous
sandstone which weathers to a curious moss-like form ; in fact the
beds seem to correspond exactly with those of the section 1 at Jebcl
Ter, near Kharga, and that of Jcbel Omm-el-Ghenaim quoted by
Zittcl from Schweinfurth. The extent of the limestone is not large,
not moro than about 8 miles from north to south and perhaps as
much as 15 to 20 miles from east to west.
The spring itself is situated on the south side of a small fault
with a downthrow of perhaps 20 feet to the south, and its direction
is about 25° N. of E. for a distance of about a mile. This direction
is only maintained locally, for the dips usually observed along the
road to the north of these springs for 30 miles are N. N.E., and
S. S.W., the strike being some 20° S. of E. Farther north the dip
becomes too small to be readily determined, till we come to the
Kharga Oasis.
In dealing with rocks such as the Nubian Sandstone, exposed
over large areas and not presenting any marked lithological
difference between the beds, it is extremely difficult to trace the
minor folds across a country where want of water compels the
observer to keep to certain definite tracks or to hurry from point to
point. This must be my excuse for attempting to elucidate the
stratigraphy of the Libyan Desert from such slender data, but the
exceptionally uniform character of the beds facilitates tho endeavour.
Dr. Zittel has pointed out that the springs of the oases are
fed from an underground water-bearing bed which draws ita
supplies from tho rainy districts of Darfur, etc., to the south, and
not from the Nile. The water drains down the dip-slope of these
sandstone beds, till it can find its way to the surface through fissures
in the overlying beds, or by artificial borings, being forced up by
the pressure due to the elevation of the gathering-grounds to the
south. Thus we shall have the water brought nearest to the
surface at points on the axes of the anticlinal folds, and may expect
therefore to find that the oases and desert springs are so situated.
Should this prove to be the case, the whole question of an increased
water-supply for the oases — in other words, their improvement arid
development — is intimately connected with the geological structure
of the area.
To the west of the Arbain road from Assiut to the oases of
1 Zittel, op. jamcU. p. 80.
Digitized by Google
VoL 50. j
PHYSIOGRAPHY OF THE LIBYA* DKSEltT.
539
Kharga and Solium there is another desert track known as tho
Terfau road, which runs a little east of south from the village of
Mut in the Dakhla Oasis for the first 80 miles or so. Although I
could not get as far as the well, several considerations caused me to
mark a point about 100 miles south of the oasis as the probable
sito of this well, Bir Abu Tarfa ; and after seeing tho geological
structure of Bir Murr, the conviction grew that it was situated eithor
on the same anticlinal fold as this latter spring, or on the one passing
through Wadi Haifa. A few days later, on meeting an Arab who
had travelled this road, the distances that he gave mo appeared to
confirm the inferred position of this well.1
If we prolong the direction of the Bir Murr fold eastward, it is
found to cut the Nilo just by Korosko, and seems to have been tho
cause of the river making a sudden bend at this locality, impelling it
to work along the fold till the easiest point of crossing it was reached.
Passing for a moment to tho other desert wells to the south, we
find about two days' journey south of Bir Murr a group of wells,
known as Eassaba, Nakhlai, and Shebb, the water occurring in each
case a few feet from tho surface. Between these and tho Nile we
have the intrusive olivino-doleritc of Jebel Burka, about 20 miles
W.N.W. of Wadi Haifa, aud about 15 miles down the river from
this place a spring runs into the Nile on its western bank, and
may be seen trickling over the rocks at low Nile.
The general direction given by these is slightly more south of east
than that of the anticlinal at Bir Murr, but it is difficult to avoid
the idea that these springs are duo to a similar anticlinal fold,
which may also have assisted to bring the Archsean rocks of the
Second Cataract to the surface.
The next wells to the south are those of the Selima Oasis, which
is not at present accessible for geological examination, but tho map
of this region ( W.O. Intelligence Map, No. 0G2) shows to the south
of the oasis " 00 miles of alternate ridge and valley," which I
believe are tho eroded strata of the southern portion of an anticlinal
fold, similar to that at Bir Murr, passing through the Selima Oasis.
The occurrence 2 of beds of limestone at both these places increases
the resemblance. The direction of these ridges is not more south of
east than that of the Shebb wells, and, just as we have seen the
river deflected by the Bir Murr fold at Korosko, so does it appear
possible that the great bend of the Nile between Dongola and Berber
may be due to the resistance offered to it by the Selinia anticlinal,
which turned back the river to wander in the synclinal trough till
it found a place to cross in the neighbourhood of tho Third Cataract.
North of Bir Murr the granite exposure of Jebel Abu Bay an and the
springs in the neighbourhood of Beris at the south of tho Kharga
Oasis form, with tho oasis of Kurkur and the exposure of the
crystalline rocks at Assuan, another parallel line, and the section
published by Zittcl 3 shows tho presence of an anticlinal curve in
Dakhla. I have already pointed out how these folds appear to have
1 [Recently (June 18W) the well has been found ;j0 miles W.N.W. of Shebb.]
3 W. Willcocks, « Report on Perennial Irrigution and Flood Protection lor
Egypt,' Cairo, 1804, App. iii. p. 5. 3 Op. jam tit. map.
540 CUT. H. O. LYONS 05 THE STRATIGRAPHY AND [Nov. 1 894,
influenced the course of the river at Korosko and at the Third
Cataract, while between these points it runs at right angles to the
direction of the folds ; it is also of interest to note the grouping of
the wells in the Eastern desert. Till that part is carefully examined
nothing of course can be said with certainty, but I would point out
that the prolongation of the Bir Murr-and-Korosko line falls on the
wells of Keriyat, Haimar, and Movia, with Derehit farther east,
and that the general direction of the valleys, especially the upper part
of the Wadi Allaki, is the same ; while the wells of Khattat, Um Rish,
Khosfur, Kept, Sufir, Medina Dilet-el-Dom and Murat, with that
of Shikr farther to the east, are on the Shebb-and- Wadi Haifa line.
North of the area we have hitherto been considering, a series of
folds, having a general north-and-south direction, come in and are
well seen in the Kharga Oasis from the village of Bulak northwards,
where the strongest springs occur, as usual, situated along them.
In some cases ancient springs occur at heights of 60 to 80 feet
above the level of the plain, and in old times yielded an abundant
supply, but now are sanded up and closed through neglect, only
furnishing enough moisture for a few dom-palms which still grow
round them.
At the Farafra Oasis the folds seem to be rather east of north,
judging from Zittel's map, and to pass through the Baharia Oasis,
5 mile^ north of which I saw most marked anticlinal folding of the
Upper Eocene lirae.stone-beds. By the villages of Mandisha and
Zubbo, in the northern part of this latter oasis, there was distinct
faulting of the Cretaceous sandstone-beds, which have been brought
up till they form the floor of the oasis, and in them the springs
occur, the water-bearing rock being met with at a depth of about
90 feet from the surface, furnishing a most abundant supply.
The Natron Lakes owe their water-supply, I believe, to a fault
along the line of the valley bringing up the water to form a line of
springs. These springs are, as a rule, fresh, and take up sodium
chloride from the surface-beds, but, after percolating slowly through a
reedy marsh with much decaying vegetation, water appeal* containing
sodium carbonate, which is deposited on evaporation of the lakes.
The springs in this valley, which is very little — if at all — above sea-
level in the neighbourhood of the lakes, are affected by the pressure
of the Nile water, and when that is in flood the water in the wells
rises slowly to a maximum of about 2 feet, as I was told, above its
lowest level. There are a few other places which require careful
examination in this connexion, to see whether any modification of
the views that I have put forward is necessary. Among these is
the Fayum, which was doubtless at one time an oasis like the
others, and was fed by springs which supported patches of vegetation
round them; but now that the irrigation is done by Nile water,
brought in by the Bahr Jusef Canal, the influence of the springs
is masked by the river-water, and is seen only in the fresh-
water springs on the edgo of Birket^el-Kurun and in the Wadi
Eayau.
Vol. 50.]
PHYSIOGRAPHY OP THE LIBYAN DESERT
541
VI. The Erosion of the Nile Valley, etc.
Altogether it would seem that tho east-and-west folding took place
at a time when the Nile, as we know it, had not begun to exist,
probably in very late Eocene or early Miocene times ; while a later
north-and-south folding,1 culminating in the Nile Valley fault at
Cairo and the great Araba fault in Palestine, with a large downthrow
to the west, finally determined the line of drainage at a later period.
The date of this last folding is not at present very easy to determine ;
but, as it seems to have been bcforo the Jebel Ahmar Sandstone, it
must have been during Miocene times.
As mentioned above, this Jebel Ahmar Sandstone lies on the eroded
surface of tho Eocene strata, and some of the marine Miocene, e. g.
that south of Jebel Atakka, near Suez, is deposited in hollows eroded
out of the Eocene rocks, so that a certain amount of erosive action
had taken place in the earliest Miocene times. Still the main work
of carving out the Nile Valley seems to have been done later, after
the north-and-south folding had determined the direction of drainage,
and after the deposition of the Jebel Ahmar Sandstone as an estuarine
deposit, while it was earlier than the late Pliocene beds and sea-
beaches which rest against the Nile cliffs of to-day at Cairo and (iiza.
Thus the early Pliocene times seem to have been tho period when the
majority of the work was done, though a certain amount was
doubtless going on later in post-Pliocene times. Prof. Hull2
attributes it to the heavy rainfall of a Pluvial Period, but for the
reasons quoted above the main part of tho work seems to have been
done in two stages, and in this I have tho support of M. Holland,3
who describes heavy erosive action as taking place in Pliocene
times in Algeria and a second period of erosion in Quaternary
times. Under these conditions, when tho northern lino of drainage
had once been established, we should have the Nile of that period
flowing through a plateau and fed by tributary streams from
the east and west, by which the upper limestone- and marl-beds
would be rapidly eroded away along their dip-slope, leaving an
escarpment on the north which was continually being cut back.
As the Nile cut its way down through the softer overlying beds it
would in time reach tho harder Nubian Sandstone or the crystalline
rocks, and on meeting them at the points whore the anticlinal folds
crossed its line the river would tend to move east or west along
the obstruction till an easier point was reached. As the Cretaceous
limestones and marls wero eroded away, the underlying Nubian
Sandstone was laid bare and erosion would now go on more slowly,
while to the north the limestone escarpment was being cut farther
and farthor back. By the time the escarpment had been cut back
as far as the southorn limit of the oases, their springs, bursting out
at the base of the cliffs, would enormously increase the rate of erosion.
1 Rolland, ' Geologie du Sahara,' p. 258.
3 'Geology of Arabia Petraja, Palestine, and adjoining District*,' pt iv.
chap. ii. p. 113, London, 1889.
3 • Geologic du Sahara,' p. 260.
542 CAPT. H. O. LYONS ON THE 8TBATIGRAPHY AND [Nov. 1894,
Wherever these springs were occasioned by an east-and-west fold
they would occur along a considerable length — so as to form a recess
such as the Dakhla Oasis, while, whero the north-and-south folds
came in, the erosive action would be most active in that direction ;
it is to this that I would attribute the width of Dakhla and the
southern end of Kharga from east to west, while the north-and-
south folds have determined the longitudinal shape of Kharga.
Evidence of this erosion was found at a spot (lat. 24° 20' N. and
long. 29° 50' E.) where a small patch of limestone occurred, composed
of blocks containing Alveolina ovoidea, Schwiig. (Lower Eocene),
bound together by a calcareous cement. In parts it was a true
limestone gravel. This mass lay directly on the Nubian Sandstone.
The beds of calcareous tufa under the cliffs of the Kharga Oasis
containing Querent ilex, etc., as described by Zittel, show that
during this earlier (Pliocene) period of erosion the oases attained
approximately their present dimensions, while I would refer the
tufa deposit to the later post- Pliocene time.
The floors of these oases are now rather below the level of the
Nile at Assuan, Kharga being 140 feet, as compared with Assuan,
280 feet above sea-level ; but though wind-action may have helped
to deepen them, the depressions and elevations of the Nile Valley
and neighbouring deserts at various times render it impossible to
say to what level tho river-action of the past could or could not
have worked.
Mr. E. A. Floyer 1 considers that no more rain than falls to-day
is required for the districts bordering tho Nile, and cites Schwein-
furth as inclining to the same opinion. Besides the erosion already
described as having taken place in early Pliocene times, evidence in
the Libyan Desert tends to show that there was a time, probably
post-Pliocene, when the desert was finally being carved and moulded
into what is practically its present form, when there was a consider-
able rainfall over the area, though not necessarily an excessive one.
Three hours west of the cliffs overlooking the town of Girga in
Upper Egypt there is 8 to 1 2 feet of flints covering the limestone
surface of the desert ; these are closely packed together, with a
small amount of iron-stained, earthy material between them. While
the topmost layer is markedly fractured and blackened by exposure,
the lower ones are usually whole and show no signs of blackening.
This seems to show that the limestone was quietly dissolved away
during a period of rainfall, till the flints accumulated to a con-
siderable thickness. Thou the physical conditions changed, and a
period of rainfall passed into one of true desert conditions, with
fracturing of the flints by variations of temperature, and blackening
of the surface-layer by exposure.
All along the foot of the limestone escarpment between Kharga
and Dakhla, and under the cliffs on the east side of the former oasis,
there arc beds of streams with rolled limestone-pebbles and boulders.
Some of this is probably due to the rare rain-storms of our own
1 Quart. Journ. Geol. Soc. vol. xlriii. (1892) p. 680.
Digitized by Google
Vol. 50.]
PHYSIOGRAPHY OF THE LIBYAN DE8EKT.
543
time, but I have no doubt that they also represent streams which
flowed when the calcareous springs were forming the tufa above
mentioned, and when the evergreen oak and other similar plants
were growing near.
I would refer to this same poriod the large gravel-sheets which in
Nubia extend for a length of 7 or 8 miles along the Nile bank at
Debera, 8 miles north of Wadi Haifa, a period when a more generous
rainfall furnished streams which eroded the beds of the neighbouring
plateau and fed the Nile, which deposited its beds of alluvium 100
feet above its present level, and maintained the beds of JEtheria
semilunata, Cyrena jluminalis, Unio, Paludina, and other shells 1
which are found at this level at Wadi Haifa, DeWa, Derr, etc.
Deposits of impure kaolin in the gullies of the Second Cataract
point to the same condition of things, when the rain was woathering
the felspars of the crystalline rocks.
Shortly to recapitulate the conditions under which this area has
attained its present state, wo have firstly an elevation of the Eocene
rocks and a certain amount of erosion of them, followed by a
depression, at all events in the northern area, whore the marine
Miocene beds wero deposited. A gradual elevation seems to have
taken place, and the Jebel Ahmar Sandstone was deposited. An
elevation 2 of the area in Pliocene times caused the Nile to erode its
bed deeply, and the main work of plateau erosion and the formation
of tho southern oases was commenced. A depression of tho area
at the time of the deposition of tho late Pliocene sea-beaches,'
near Cairo, checked this eroding action and probably caused the
deposit of the high-level Nile mud with beds of sEtheHa, etc. A
later elevation with a climate of moderate rainfall enabled the
river to cut out its present bed below the earlier Nile-mud deposits,
and one is almost tempted to go further and attribute tho present
silting-up of tho Nile bed below tho First Cataract to a recent
depression of the area, at all events to tho north, as is shown by
Roman tombs near Alexandria, which are now below sea-level.
Much has been made of the fact that the rainfall of to-day has
formed deep valleys on the eastern bank of tho Nile, but I am
incliued to think that, while the rainfall of post-Pliocene times
eroded both sides of the river, tho physical conditions were widely
different. On the west was a gently rising plateau which was not,
perhaps, very deeply eroded, and since then thousands of years of
wind- and sand-action under desert conditions have ground away
and obliterated most of the traces of this rainfall. On the east a
high ridge of crystalline rocks gave tho streams a more rapid fall,
and so vastly increased their eroding power, while then as now they
caused precipitation of moisture carried by currents of air from the
eastward ; thus the gorges and valleys once formed have been kept
1 Leith Adams and S. P. Woodward, Quart, Journ. Gcol. Soc. vol. xx. (1864)
pp. 14 and 19.
3 Jukes-Browne. • Physical Geology,' pt. iii. ch. ii. 2nd ed. 181)2.
3 Theeo are small patches, too minute to bIiow on any but a large-scale map.
Digitized by Google
544 CAPT. 11. O. LYONS OK THE STRATIGRAPHY AND [NOV. 1894,
open, even if they have not been much deepened in these later time9,
and within the past four years three cases have been brought to my
notice where torrents have rushed down the eastern valleys, leaving
marks which will remain for many years to come.
Besides the geological evidence of the shell-beds and deposits of
Nile mud there is also historical evidence of the Nile having
reached a higher level in Nubia in ancient times than it does to-
day. On the rocks at Semna, 45 miles south of Wadi Haifa,
inscriptions of the Xllth Dynasty (about 2200 b.c.) speak of the
Nile flood having reached a point which is 27 feet above its present
flood-level. Opposite Wadi Haifa, close to the river-bank, are tha
remains of a mud-brick temple built in the time of Usertesen I.,
that is, rather before the Semna inscription, and this temple continued
in use down to the time of Ramses XIII. (about 1100 b.c). The
floor of this temple is 14 feet above present flood-level, and any
greater rise than this would flood the templo. In the time of
Thothmes II. and Thothmes III. (about 1600 b.c.) another temple
was built alongside the first, with a flight of steps leading to the
river, but they stop with a vertical face somo 8 to 10 feet high at
a point 19 1 feet above present low Nile and more than 7 feet below
present flood-level.
At somo time subsequent to 1100 b.c, when the temple of
Usertesen I. was no longer used, but had fallen into decay, the
vaulted mud-brick roof having fallen in, the temple site was flooded
to a height of 15£ to 17 feet above present flood-level. Over the
drift-sand which had blown in there is a regularly-bedded, fine,
white sand, and on this is | to £ an inch of the finest grey mud-
silt which has settled from the ponded-up water. On this silt,
which is sun-cracked and rain-pitted by an easterly shower, are
the carbonized remains of twigs and grasses, so that the flood
evidently came from the Nile and not from a heavy storm in the
neighbouring hills, which would have brought down stones, broken
pottery, etc. ; moreover, a rise in the ground behind the temple
would have deflected such a torrent to one side or the other.
Thus we have : —
2200 b.c A temple at Wadi Haifa, floor 14 feet above present
flood-level.
2000 b.c. High Nile level at Semna, 4o miles south, 27 feet
above present flood-level.
1600 b.c Another temple floor about 17 feet above present
flood-level, and a stairway onding in a perpendicular face at
a point about 7 feet below present flood-level.
After 1100 b.c The northern temple is flooded, while the other,
the Thothmian temple, at a slightly higher level, shows no
signs of it, except that at some time, perhaps then, the brick
wall round it was doubled in thickness.
Seeing that Wadi Haifa and the Second Cataract are situated on
the same series of folds as the wells of Shebb. etc., I would suggest
that these variations of the river were caused by earth-movements.
Digitized by Google
Vol. 50.]
PHYSIOGRAPHY OF THE LIBYAN DESEItT
545
Whatever held up the river to the high level at Semna must have
been in the Second Cataract for the most part, as half the amount of
rise recorded at Semna would have flooded the temple site at Wadi
Haifa.
One point I may suggest as worthy of consideration is that the
folds of Farafra and Baharia, and the Shebb and Murat wells,
intersect at a point up to which the old caravan-route S.W. from the
Dakhla Oasis directly leads. It appears possible, therefore, that in
the sandhills of this part there exists, or has existed, another oasis
of which we have at present no certain knowledge.
VII. The Origin of the Siucifted Wood.
There is no doubt that the siliceous cementation of the sandstone,
and the molecular replacement of the woody structure of the fossil
trees by silica, arc results of one and the same action, which has been
ascribed to geysers by Schweinfurth and by Sir J. W. Dawson,' while
Zittel has distinctly stated that he does not consider this a prac-
ticable theory, and points out the absence of siliceous trinter.
Whatever theory proposes to account for the sandstone and trees
near Cairo must of course also account for those west of the
pyramids of Giza, over the wide tract where I have shown the Jcbel
Ahmar Sandstone to occur ; and, looking at the similarity of the
fossil wood from the Nubian Sandstone and of the silica-cemented
sandstone from various localities in Nubia, it is hard to avoid the
idea that similar agencies worked in each case to produce results
so identical. Over the whole of this area, at three points only, viz.
Jebel Burka near Wadi Haifa, Mandisha in the Baharia Oasis, aud
Abu Zabel near Belbeis, have eruptive rocks l>een recorded, and
nowhere have I met with, nor does Zittel in his account of the
Bohlfs expedition mention, any siliceous deposit analogous to the
sinter deposited by the waters of geyser-springs. Considering the
large amount of decaying vegetable-matter there must have been in
the sands of an estuary into which such numbers of trees were
drifted, I would suggest the action of water holding natron (sodium
carbonate) in solution as a possible explanation.
This would act upon the felspar-grains in the sands derived from
the crystalline rocks, and would form sodium silicate, while the
potash of the felspar would take up the carbon dioxide in place
of the silica. On this solution of sodium silicate coming into contact
with the decaying vegetation in the sands, the vegetable acids pro-
duced in the course of decomposition, and probably carbon dioxide
also, would replace the silica which would be deposited as a cement,
or as replacing molecule by molecule the woody structure of the
trees. And I think wo may take this explanation as equally
applicable to the Jebel Ahmar or to tho Nubian Sandstone, for in
the area occupied by the first we have the Natron Lakes with
their springs and natron-deposits, while round Bir Malha, south
» Geol. Mag. 1884, p. 386.
Digitized by Google
540
CAPT. H. Q. LYONS ON THE 8TRATI6BAPHY AND [Nov. 1894,
of the Selima Oasis, are very extensive natron-deposits in the midst
of the Nubian Sandstone area.
Dr. A. H. Hooker, Director of the Salt Department of Egypt,
informs me that lie has seen silicification of woody structure in
progress to-day in the Wadi Natrun.
PLATE XXI.
Geological Mnp of the Libyan Deeert of Egypt, at the scale of ]-7—
= •021 1 inch to the nnle, or about 50 inilea to 1 inch. ^O00 000
1
Discussion.
The President congratulated tho Author on the good use that he
had made of his opportunities in carrying on geological observations
in so very difficult a country as tho Libyan Desert — a country so
destitute of escarpments. The Author had made use of lines of wells
when no other feature was available to guide him in predicting. the
underground lie of the rocks. From the evidences cvervwhere of
a?olian action, and the abundance of silicified and highly weathered
tree-trunks, it appeared that this area must have been exposed to
subaeriul conditions through a vast period of time as an old land-
surface. He hoped that Capt. Lyons would make further good use
of his military travels in tho Desert.
Mr. Hudlkstox congratulated the Society on at last receiving an
interesting paper on the geology of the Egyptian Desert, where tho
general conclusions of well-known authors were confirmed and
supplemented. He would like, amongst other matters, to have a
possible explanation of a statement made here two years ago, that
the Nubian Sandstone rested on basalt, but was invaded and meta-
morphosed by granite. Tho absence of the sandstone of Car-
boniferous ago was not surprising in the level area, but when
Capt. Lyons carried out his plan of investigating the Eastern
Desert, it was not improbable that he would find this formation on
the margin of the crystalline mountain-chain flanking the Red Sea.
The silicification of large masses of wood was a feature characteristic
of all the sandstone-beds of many ages in Egypt. Was this feature
a contemporaneous one, or had there been a period of general silici-
fication ? The methods by which this had been effected were the
result of replacement due to decomposition of woody tissuo, and were
observed in all parts ef the world. The hydrographic questions
raised by Capt. Lyons were of extreme interest and economic
importance. He had received a good training in a sandy, thirsty
district nearer home, namely, the Bagshots.
The Rev. G. Hkxslow remarked upon tho great practical import-
ance of Capt. Lyons s observations as to the Nubian Sandstone
being a water-bearing stratum : thereby correcting tho old view that
oases were low-lying localities in which the water of the Nile, by
penetrating soft strata, was accessible by wells. He observed that,
by following the anticlinals to north-western localities, water might
probably be found in the Western Desert., in places where it is at
present unknown. He also drew attention to tho evidence of earth-
Digitized by Google
I
1
■
i
i
Digitized by Google
igmzea Dy
Google
Vol. 50.]
rnrsioGRvrnr of the libyax desert.
547
quakes at Wadi Haifa, etc., as seen in the demolition of the templo at
Karuak, and in vertical rifts on the face of perpendicular rocks, on
which figures were sculptured that were now split completely down :
Wadi Haifa being, as Capt. Lyons observed, in the direct line of the
anticlinals, which extended in a slightly N.W. and S.E. direction.
Prof. Hull concurred with the Anew of the Author that the course
of the Nile above Cairo had been determined by the line of fault,
which follows the valley for many miles upward. As regards
the age of the Nile in Egypt, he considered it as referable to the
Miocene stage rather than to the Pliocene. The Miocene period in
that part of the world was one in which the main features of the
present land-areas received their general contours. Referring to an
observation by Mr. Hudleston regarding the absence of Carboniferous
beds in the Nile Valley, ho reminded the Society that deposits of
this age had been discovered by Dr. Schweinfurth in the Wadi-cl-
Arabah, between the Nile and the Gulf of Suez.
Dr. Ikviko could not resist the temptation to say a word to con-
gratulate his old friend and former pupil on the excellent use ho had
made of the opportunities which his service in Egypt had put in his
way, and on the interest of the results of his work now beforo the
Society. Remarking on the silicification of wood, he wished again to
emphasize the difference in the action of carbonic acid in petrological
changes, according as it existed as a free acid or in combination with
a base, as in sodium carbonate. The extent of the • Natron ' deposits
pointed to tho supply of alkaline waters over large areas in former
times, holding the mineral in solution. The reaction of such waters
upon the potash-felspar of the sands, furnished by tho disintegration
of the crystalliue rocks, would not lead to the deposition of free
silica (as in the ordinary process of kaolinization), because, while the
potassium was taken up as a carbonate and carried away, the silica
was also removed in solution, through combination with the sodium,
to form sodium silicate. This last-named salt in solution would be
readily decomposed by tho organic acids and tho carbonic acid fur-
nished by decaying vegetable tissue, the silica being then deposited
as a colloid in situ, and thus retaining the structural forms of the
original tissue.
The Author, in replying, agreed with Mr. Hudleston as to the
occurrence of Carboniferous beds underlying the Nubian Sandstone
east of tho Nile, but he had been unable so far to detect them in
tho Libyan Desert. The silicification of the fossil wood he believed
to occur separately in each period, and were Egypt of to-day a
wooded country, he would expect to find the same in progress in
the Delta. Ho agreed with Prof. Hull that the north-and-south
folds of Kharga were probably connected intimately with the Nile
Valley fault. Dislocations fracturing inscriptions show movements
to have taken place in historic times, as suggested by Mr. Henslow ;
and tho water-system of the Desert, as determined by the folds of
the strata, seems to indicate the position of oases other than thoso
that wo at present are acquainted with.
Q. J. G. S. No. 200. 2 a
Digitized by Google
548
MR. D. DRAPER ON THE GEO LOOT
[Nov. 1894,
3o. Notes on the Geology of South-eastern Africa. By David
Draper, Esq., F.G.8. (Itcad May 23rd, 1894.)
[Plates XXII. k XXIII.]
Contents.
Page
I. Introduction : Physical Features 548
II. Geological Feature* 550
III. Conclusion 556
IV. Supplemental Botes on the Dwyka Conglomerate... 559
I. Introduction : Physical Features.
I purpose, in the following pages, to give a brief description of the
principal physical and geological features of that portion of South
Africa which is situated between the 26th and 31st degrees of south
latitude and the 20th and 31st degrees of east longitude.
This area includes the Colony of Natal, the native States of
Zululand and Swaziland, the south-eastern portion of the South
African Republic (Transvaal), and the eastern portion of the Orange
Free State and of Basutoland.
The leading physical features of this area are : —
(1) The Drakensberg Range.
(2) The ' Terrace,' lying along the foot of the Drakensberg.
(3) The Coast-belt, between the Terrace and the Indian Ocean.
(1) The Drakensberg Range.
This range of mountains is the continuation of the main range,
which runs roughly parallel with the coast-line of Cape Colony, from
west to east, and turns rather suddenly northward at the Natal
boundary. It is known under various names in Cape Colony, and as
the * Drakensberg ' where it forms the boundary of East Griqualand
and the Colony of Natal.
The Drakensberg forms the watershed of the south-eastern
portion of the continent ; it divides the waters flowing westward
into the Atlantic from those flowing eastward into the Indian Ocean.
The rivers flowing westward, viz. the Orange and the Vaal, drain
the inland portion of South Africa. Those flowing eastward, the
principal of which are the Tugela, the TJsuto, and the Pongolo, drain
the coastal portion. These latter are small in comparison with the
Vaal and Orange rivers.
The Drakensberg range consists of three distinct portions,
differing greatly in aspect. (See PI. XXII.)
(a) The Mountain portion^ extending northward to the * Mont-
aux-Sources,' forming a bold and rugged mountain-chain,
inaccessible except by means of a few obscure aud dangerous
Vol. 50.]
OF SOUTH -EA.STERN AFRICA.
native footpaths, attaining an altitude of from 9000 to
10,000 feet, and culminating at the peak named by the
French missionaries the * Mont-aux-Sources,' about 11,000
feet high.
Several of the principal rivers of South Africa rise from
this peak : the Orange and the Caledon, southern branch
of the Vaal, flowing westward, and the Tugela flowing
eastward.
(b) The hill-covered plateau, extending from the Mont-aux-
Sources northward to the Vaal River. This plateau is about
0000 feet above sea-level, and numerous hills, remains of a
former range, are scattered about the surface. Several of
these hills riso to an altitude of from 8000 to 9000 feet
above sea-level.
(c) The High-veld plateau, extending from the Vaal River north-
ward to the Klip Stapel and Lake Chrissie.
It consists of rolling plains, from 6000 to 8000 feet above
sea-level, the highest eminence beiug the Klip Stapel, near
Lake Chrissie. The northern branch of the Vaal River rises
at this spot.
The High-veld plateau is devoid of hills : innumerable
small lakes (' pans ') are dotted about its surface, especially
in the neighbourhood of Lake Chrissie.
Both the * Hill-covered plateau ' (6) and the * High-veld plateau ' (<•)
end abruptly eastward, but slope gradually westward.
The eastern termination of the plateaux forms the continuation
of the Drakensberg range in Natal and in the South African Republic
(Transvaal).
The whole of the Drakensberg range and the plateaux are devoid
of timber; they are covered with short grass, forming admirable
pasture-land for stock. The climate is healthy, though excessively cold
in winter, snow falling frequently and covering the higher mountain-
tops. Trees grow well where cultivated, especially the oak and several
species of pine. Silicified trunks of trees are very numerous in parts
of the High-veld plateau, especially near the town of Harrismith,
Orange Free State. They are only found about 5000 feet above
sea-level.
(2) The ' Terrace/ lying along the eastern foot of the
Drakensberg. (See PI. XXII.)
The average height of this terrace above sea-level is about
4000 feet, and it stretches for about 80 to 100 miles from the
Drakensberg range towards the coast.
Numerous spurs of the main range and detached hills (outliers)
have survived the general destruction of the great plateau, which,
judging from these hills, must have extended beyond the limit of
the terrace eastward. This terrace terminates somewhat abruptly
towards the coast, where it forms an escarpment from 2000 to 3000
feet high, at the foot of which lies the Coast^belt.
2q2
Digitized by Google
550
KB. D. DBA PER OX THE GEO LOG! [Nov. 1 894,
The climate of the Terrace is healthy for man and beast ; though
the days are very warm in the summer months, the nights are cool
and refreshing. The winter is mild, snow seldom falling.
Numerous rivers flow through this terrace from the Drakensberg,
and in consequence it is doeply furrowed. Valleys, reaching down
to the granite, have been cut out by these streams, especially on the
edge of the Terrace eastward ; some of these valleys are 80 miles
in length, flanked by spurs of the Drakensberg, 3000 feet high
above the valley-level.
Small forests are dotted over the surface of the Terrace, but upon
the whole tho country is devoid of timber, except along the edge of
the Terrace, where some forests of indigenous pines are found growing
in the moro sheltered valleys.
(3) The ' Coast-belt/ lying between the Terrace
and the Indian Ocean.
This belt is from 30 to 00 miles in width and continues all along
the coast of Natal, Zululaod, and Swaziland. It is generally low-
lying and unhealthy, except along the Natal coast, where whites
have resided ever since the occupation of the colony. (Sec PI. XXI I.)
The climate is sub-tropical, that is, extremely hot in summer, and
temperate in winter.
Low rounded hills are the most prominent feature of the land-
scape, and along the shore sand-dunes and lagoons are frequently
met with. Vegetation grows very luxuriantly, and the country is
covered with dense bush.
II. Geological Features.
The principal groups of rocks which may be identified in the area
under description are the following : —
Upper Knroo.
Lower Karoo.
Primary rocks. 1
Basement-rocks.
{Volcanic rooks.
C ate- sandstone.
Rod Bods.
Molteno Beds.
Beaufort Beds.
Ecca Beds.
Dwjka Conglomerate.
''Quartzito of the Gats Band (in
the Tran*vaal).
Mai ma ii i Limestone (dolomite).
[Bokkereld Beds, wanting].
Table-mountain Sandstone.
Malmc*bury Schists.
Gneiss and Granite.
Probably Jurassic.
Probably Triassic.
Probably Permian.
I have failed to discover some of the other South African groups,
such as the quartzitcs of the Zuurberg 1 and tho Zwarteberg, though
I made search for them over a great portion of the country.
In the Transvaal this formation is represented by the quartxite of the Gats
. — T. R. J.]
Rand
Digitized by Google
»
Vol. 50.] OP SOUTH-EASTERN AFRICA. 551
I do not intend to enter into a minute description of the rocks
composing the various groups in South-eastern Africa, hut merely
wish to place on record their mode of occurrence and the position
they occupy.
(1) Volcanic Beds.
( Tra p-amygdaloids. )
These occur only on the tops of the higher peaks of the Drakens-
hcrg, in tho mountain-portion a (see p. 548). They form a most
fantastic capping to the mountain-range, rising in peaks and pin-
nacles to 1000 feet in height above tho sedimentary rocks of the
range.
This group docs not extend farther northward than the Mont-
aux-Sources, and is rarely found lower than 8000 feet above sea-level.
None of the higher eminences of tho plateau or High-veld portion of
the Drakensberg are capped with these rocks, which apparently
never covered the sedimeutary deposits northward of the Mont-aux-
Sources. The Cave-»aud.stone forms tho hill-tops of the plateau 6.
(PI. XXII.)
(2) Cavc-sandstone.
This group attains a thickness of between 500 and 700 feet, and is
found underlying the volcanic beds, wherever they occur on the
Drakensberg range.
It forms the crag-crowned tops of most of the hills situated on
the plateau or ^-portion of the Drakensberg, but does not extend
northward of the Vaal liiver on to the High-veld plateau. If it ever
was deposited there, it has been completely removed by denudation.
The specimens of Stmionotus caperw*y CltithroUpis Kctoni, and
a new species of Dictyopyt/e (?) described by Mr. A. Smith Wood-
ward (see Ann. & Mag. 2Sat. Hist. ser. 0, vol. xii. 1S93, p.
pi. xvii. fig. 1), have been found in the Cave-sandstone in the
neighbourhood of the villages of Ficksburg and Rouxville, in the
Orange Free State.
(3) Red Beds.
This group occupies a small area in the vicinity of the town of
Harrismith (O.F.S.), and is exposed in tho lower portion of the Plat-
Berg, on the town-commonage, extending southward into « Vitsies '
Hoek, towards the Mont-aux-Sources.
It is about 100 feet thick at the section near Harrismith, and
contains a bed of bone-breccia, principally composed of reptilian
remains. Specimens from this bed were sent to tho Royal College
of Surgoons by Messrs. Orpen, and noticed by Prof. Huxley in the
Society's Quarterly Journal, vol. xxiii. (1867) p. 5, having been
previously described by Prof. Owen in his Catalogue of the Fossil
Rept ilia in the Museum of that Collego (1854).
Northward, towards the Vaal River, the Red Beds do not appear
to exist, but seem to be replaced by a dark-coloured, gritty sandstone,
containing worn crystals of felspar, of considerab) t siz*» and rounded
Digitized by Google
552
MR. D. DRAPER ON THE GEOLOGY
[Nov. 1894,
quartz-pebbles about the size of pigeons5 eggs. The dark colour of
the rock is caused by the quantity of manganese oxide, which occurs
in small veins and beds in the rock, and generally completely
envelopes the quartz-pebbles.
Silicified remains of trees are abundant in the upper portion of
the Red Beds and in the dark-coloured grit.1 In many cases the
lower portion of the trunk is found standing erect, on the spot
where the tree originally grew. Some of these trees were of con-
siderable size, judging from their silicified remains, which measure
over 4 feet in diameter in occasional specimens.
(4) MoltenoBeds.
This extremely important series occupies a large area in South-
eastern Africa.
The High-veld plateau of the Drakcnsberg (<•), and nearly the
whole portion of the Terrace, lying north of the Tugela River," is
composed of this series, which is the coal-bearing formation of South
Africa, and contains the only workable coal-seams yet discovered
there. Prof. A. H. Green has very ably described the Molteno Beds
as he found them in Cape Colony,' and his description applies
generally to the series wherever it occurs in South Africa.
There are a few points of difference, however, between the
Molteno Beds of Cape Colony and the same strata in South-
eastern Africa, the principal of which are (lstly) the absence of
boulders, which Prof. A. H. Green noticed as occurring in the
Molteno Beds in Cape Colony. These I have never found any-
where in Natal or in Zululand, in the districts where the Molteno
Beds are most exposed to view, and where admirable sections can
be obtained. (2ndly) The superiority of the coal over that of
Cape Colony. Some of the coal-seams of the Transvaal and Natal are
only slightly inferior to ordinary English coal, and are now taking
the place of the imported article for all engine work.
The coal-beds are contained in the lower 500 feet of the series,
which consists principally of false-bedded gritty sandstones, with
inferior beds of shale, generally overlying the coal-seams, which
rest on gritty sandstone.
The upper portion of the Molteno Beds consists of grey and dark
coloured shales, interstratified with small bands of sandstone.
The most prominent feature of the Molteno Beds along the
eastern flank of the Drakensberg is a thick columnar dolerite,
which lies between the Molteno Beds and the1 Red Beds/ and
forms a crag along the mountain-side, about 200 feet high, and
extending for over 100 miles.
1 [Described by G. W. Stow, F.G.S., in his Reports on the Geology of the
Orange Free State, 1878 A 1879. — T. R. J ]
2 This portion of the country, including Zululand, has not yet been geologic-
ally mapped.
i See Quart. Journ. Geol. Soc. Tol. xUt. (1888) p. 248.
Vol. 50.]
OF SOUTH-EASTERN AFRICA.
553
Tho Molteno Beds on the High-veld plateau (e) are composed
almost entirely of sandstone ; there the upper, shaly portion of tho
series is wanting.
The cool occurs at a much greater altitude than that of the
Terrace. Near Lake Chrissie a coal-seam crops out about 6000 feet
above sea-level, while the coal of Natal and Zululand is only about
4000 feet. This would lead to the supposition that a great fault
intervenes ; and in all probability that is the case, though the exact
locality of the fault has not yet been traced.
The Molteno Beds thicken northward towards the Transvaal ;
from 1000 feet in the Drakensberg near Pietermaritzburg, Natal,
to 2000 feet at Newcastle in the same colony. The best coal
discovered on the Terrace is in the Division of Dundee, in the
northern portion of Natal.1
8mall patches of Molteno Beds occur along the coast-line of Natal
and Zululand. These dip seaward at an augle of about 20°, whilo
the same series inland lies approximately horizontal.
These Molteno Beds of the coast, which occur at sea-level, are
4000 feet lower than the lowest inland beds, having been displaced
by a great downthrow, traceable by a distinct line of faulting in
the immediate neighbourhood. A largo bed of good anthracite has
recently been discovered near St. Lucia Bay on the east coast.
(5) Beaufort or Karoo Beds.
Unfortunately for the student of South African geology, no uni-
form classification of the South African rock-systems has been
decided upon. Names have been given to the strata, to suit
the views of the observer who has described or identified them.
Sometimes the same division is known under two or three different
names ; and a great deal of confusion is the result.
Looking through Prof. Green's communication to this Society,
Quart. Journ. Geol. Soc. vol. xliv. (1888), I find he has omitted the
1 Beaufort Beds ' from his classification, and substituted 4 Karoo BedV
and 4 Kimberley Shales.' The latter I have failed to identify in
South-eastern Africa ; but tho Karoo Beds, as described by him at
p. 26 1 op. cit., occur, and are exposed on the edge of the Terrace,
forming crags along the sides of the hills. The characteristic sphe-
roidal weathering is very marked, and consequently these crags are
readily mistaken for flat igneous sheets, to which they bear a close
resemblance, when viewed from a distance.
The coarse gritty sandstones of tho Molteno Beds pass gradually
downward into finer-grained, laminated, arenaceous shales, and
then into the buff-coloured, fine-grained sandstones which compose
these Beaufort or Karoo Beds.
Weathering brings out the spheroidal structure of this rock ; the
separate masses, when broken up, showing concentrio circles of
differently coloured sandstone. Though the Karoo Beds are appa-
rently 200 or 300 feet thick in the southern portion of the Terrace,
1 See F. W. North's Report on the Coalfields of Natal, Dept. of Mine*, 1881.
Digitized by Google
■
554 MB. D. DRAPER 05 THE GEOLOGY [NoV. 1 894,
especially near Pietermaritzburg, they die away completely north-
ward, and disappear before reaching the Pongolo River. About
10 miles south of the Pongolo, they occur underlying the Doembe
Mountain, but are only about 50 feet thick at that place. I failed
to find any trace of this series north of the Pongolo.
(6) Ecca Beds.
Apparently this group is identical with the 4 Pietermaritzburg
Shales ' of Dr. Sutherland.
A most characteristic section occurs near the town of Pieter-
maritzburg, where the beds are more than 2000 feet thick ; and the
whole of Natal westward of this town, up to the Klip River, besides
a large portion of Zululand, is composed of these Ecca Beds. They
thin out rapidly northward, disappearing near the Pongolo River ;
and they do not reappear in Swaziland, lying to the north.
The Ecca Beds consist principally of dark-coloured shales and
fine-grained sandstones. I could not trace any signs of contortion
in them along their eastern outcrop ; and I feel little doubt that it
L> conformable to the underlying < Dwyka Conglomerate.'
(7) Dwyka Conglomerate.
(' Glacial Boulder-clay ' of Dr. Sutherland.)
Some exceedingly fine sections of 4 Dwyka Conglomerate ' are
exposed in the deeper gorges of the Terrace, where crags of this
rock occur, over 7(H) feet in height, showing distinct lines of strati-
fication and unmistakable evidence of the aqueous deposition of the
material constituting this rock.
The characteristics of the conglomerate noticed by Mr. E. J.
Dunn and Prof. A. H. Green, and so well described bv them as
occurring in Cape Colony, are equally distinct in South-eastern
Africa, and a description of this rock in one part of the country
will answer for any other part.
But I have failed to find any signs of contortion or crumpling
of this series along its eastern outcrop, where it is found lying
horizontal. Nearer to the coast, however, it has been disturbed,
together with all the overlying strata, by the great fault occurring
there, and is consequently found dipping seaward, outside of the
line of faulting, and considerably lower than on the inner side of
the fault.
I have not yet succeeded in finding any traces of ice-scratching
or grooving in this series, or on the boulders contained in the body
of the rock ; but ripple-marking is frequently met with, and the
whole appearance of the rock suggests the action of water. A small
patch of horizontal Dwyka Conglomerate containing very few pebbles
or boulders, but very much ripple-marked, occurs on the coast-belt
in Zululand and Swaziland, about 800 feet above sea-level, and at
least 1000 feet lower than the main body of the conglomerate along
the flank of the Terrace.
Digitized by Google
Vol. 50.]
OF SOUTH-KASTKILV AFUICA
f>55
The Dwyka Conglomerate continues in one unbroken line, from
St. John's River, through Pondoland and Natal, to the Umkuze
River in Zululand ; it thins rapidly towards Swaziland ; and near
the Pongolo River it dies away completely, disappearing at about
the same spot as the Ecca and Karoo Beds.
The largest mass of foreign rock that I have found embedded in the
Dwyka Conglomerate was a boulder of granite, 9 feet long by 4 feet
wide, and protruding 3 feet above the matrix ; I do not know how
deep the boulder extended into it. In common with all the other
(smaller) boulders this was rounded at the auglos, and showed con-
spicuous signs of having been submitted to severe aqueous action ;
but I could find no signs of any ice-action, either at this or any other
spot. I noticed one feature in the Dwyka Conglomerate in South-
eastern Africa which I have not seen hitherto mentioned, and that
was the occurrence of great intrusions and flat sheeta of igneous rock
(dolerite), the latter either over- or underlying the conglomerate, and
sometimes both above and below.
The controversy about the origin of the matrix of the Dwyka
Conglomerate has not, I believe, so far been definitely decided ; and
there appears to be as much evidence in favour of the igneous as of
the aqueous theory of the origin of the bulk of the rock.
Dr. G. A. F. Molengraaf, Professor of Geology in the University
of Amsterdam, who has studied the rock both in situ and by means
of microscopic sections, expressed the following opinion of the origin
of the rock, in a letter to me, dated January *20th, 1892 : —
" Tho Dwyka Conglomerate gives me the impression of a volcanic
tuff (I mean a probably Permian diabase-tuff), full of fragments of
older rocks. Such tuffs are not so very rare, even in diabases and
basalts themselves ; the amount of the different included rock-frag-
ments may surpass that of tho rock itself."
The masses of rounded rock and the numerous boulders and
pebble-beds contained in the Dwyka Conglomerate certainly point
to the fragments of other rocks contained therein having been sub-
mitted to the action of the ocean along a coast-line : but might not
the material of the matrix here have been principally supplied from
some volcanic region now buried beneath a great mass of sedi-
mentary strata ?
So far all the strata dealt with have been approximately
horizontal, and no signs of unconformity exist inland. On the
coast, what there is of these beds, existing only in small isolated
patches along the sea-shore, is found to be dipping seaward ; a line
of hills, consisting principally of granite and Primary rocks, inter-
venes between this series on the coast and the same rocks inland.
Tht Primary Rocks consist principally of:
(8) Table-mountain Sandstone.
This is found along the higher portions of the Bothas Hill range,
near Durban, whero it lies horizontal and in smali patches: and in
Zululand, principally near Ulundi. At this latter spot the series
55G
MB. D. DBA PER ON TILE GEO LOO Y
[Nov. 1894,
contains several beds of gold-bearing conglomerate, practically
identical with the gold-bearing conglomerates of Johannesburg.
These Zulu] and conglomerates are being worked for gold, and will
in all probability yield good returns.
I have found no trace of the quartzites mentioned by previous
writers as overlying the Table-mountain Sandstone in Cape Colony.
If these quartzites do occur in South-eastern Africa, they have not
yet been recognized by anyone who has examined the strata in
this region.1
The Table-mountain Sandstone rests unconfoimably upon the
underlying schists.
(9) Malmesbury Schists.
This series, which consists of schists, elates, shales, and small beds
of quartzite, tilted to a very high angle, and very much contorted
and crumpled, is found principally flanking the granite hills along
the coast-line and in the deeper valleys of the Tugcla, Pongolo,
Umkuze, and other rivers. It occupies a large area in Swaziland
and Northern Zululand.
Gneiss and granite are exposed in the deeper valleys ; and occa-
sionally, as at Bothas Hill, near Durban, they make small eminences.
The weathering of the Primary rocks, generally into small rounded
hills, with narrow and precipitous valleys between, shows a marked
contrast with the crag-crowned hills and broad valleys of all the later
sedimentary series.
The Malmesbury Schists (Dunn) are identical with the ' Swazi
Schists ' of Dr. Schenck, and the Lydenburg Schists and Namaqua-
land Schists of Mr. E. J. Dunn.
III. Conclusion.
From the foregoing brief description of the occurrence of the
rocks in South-eastern Africa several considerations arise, which are
likely to disturb the theories of the earlier geologists with regard to
certain phenomena which they imagined had taken place during
the deposition of the sedimentary rocks of the southern portion of
the continent.
The theory of tho late Mr. A. G. Bain, subsequently endorsed by
Mr. E. J. Dunn, as to the supposed great central lake-basin of
the Karoo, can scarcely be maintained in face of the fact that the
Molteno Beds occur on the east coast, dipping seaward into the
Indian Ocean, and at a level 4000 feet below their occurrence
inland. This denotes the extension of the Molteno Beds far
beyond the limits of the continent as at present outlined.
No doubt the Molteno Beds covered a far greater area in all
directions before the great fault occurred, which lowered them
along the coast-line, and which, in all probability, defined the shores
1 [The quartsitea of the Oats Rand ux&y be equivalent— T. R. J.]
Vol. 50.]
OF SOUTH-EASTERN" AFRICA
557
of the continent as at present existing. Consequently the shores
of any lake in which such a vast deposit of sedimentary material
(comprising the Ecca, Karoo, and Molteno Beds) could have been
accumulated must have extended far beyond the present boundaries
of the continent, and could scarcely be called a 4 central lake-basin
of the Karoo,' for this would lead one to believe that its area was
limited by what is geographically called * the Karoo/
The differences of thickness observed in the Dwyka Conglomerate,
Ecca, Karoo, and Molteno Beds lead us to suppose that great oscil-
lations of the surface occurred during their deposition.
The Dwyka Conglomerate, Ecca and Beaufort Beds thin out
rapidly northward, and die away completely near the Pongolo
River, although they attain a thickness of over 700 feet 50 miles
away towards the south ; the Ecca and Beaufort Beds also thicken
southward. On the other hand, the Molteno Beds thicken in the
contrary direction, thinning rapidly southward.
Apparently, during the deposition of the Dwyka, Ecca, and
Beaufort Beds, dry land existed in the central portion of South
Africa, notably at what is now the great northern watershed of the
Witwatersrand, and the high-lying portions of the High-veld plateau,
and extended southward to the present boundaries of Natal.
This dry land consisted of granite and Primary rocks. The
Dwyka, Ecca, and Beaufort Beds are seen to die out against these
rocks wherever they are found in South-eastern Africa. On the
other band, the Molteno Beds overlie the highest eminences of
Primary rocks and granite, even to the top of the Klip Stapel near
Lake Chrissie, 7000 feet above sea-level.
The non-existence of the Cave-sandstone and the volcanic beds
north of Natal and Basutoland respectively can scarcely be taken
as definite evidence that they never were deposited there. The
vast amount of denudation which has occurred on a territory that
has not been submerged since the close of the Jurassic period
will account for the removal of immense bodies of rock. At the
same time the Cave-sandstone is by no means so important a
formation north of the town of Harrismith as it is southward ; and
there aro evidences of a thinning of this series northward.
In the south-eastern portion of South Africa I have failed to find
the evidences of disturbance in the Ecca and Dwyka Beds described
by Prof. A. H. Green in Cape Colony. The only great unconformity
that I could discover was between the Malmesbury Schists and the
Table-mountain Sandstone. The former are tilted and highly con-
torted, occasionally being quite perpendicular ; the latter lies hori-
zontally upon their upturned edges ; the Dwyka Conglomerate, and
all the overlying sedimentary deposits, follow conformably one to the
other. As previously mentioned, all the strata lying horizontally
in the inland area dip rapidly seaward when observed near the coast,
in consequence of the great fault along the coast-line.
There is a marked distinction between the material composing
the Dwyka Conglomerate and the Ecca Beds immediately overlying
it, and consequently the junction of these two series is easily
Digitized by Google
I
553 MB. D. DRAPER ON THE GEOLOGY [NOV. 1894.
defined ; but to distinguish the Ecca from the Beaufort Beds and
from the upper series is bv no means an easy task.
They all graduate one into the other, so that the line of demarcation
in many cases cannot be determined with any degree of certainty.
Fossil evidence is very scarce, except leaf-impressions principally ot
Ghmonteris. These are found in the Molteno, Beaufort, and Ecca
Beds. So fossils have been found in the Dwyka Conglomerate u>
any part of South Africa up to the present date.
The ' Rod Beds ' yield an abundant supply of fossil reptilian
remains, and the Cave-sandstones yield specimens of fish. A portion
of a fish was discovered by the writer in the Molteno Beds of Natal,
and is, I believe, the first specimen discovered in this series ; un-
fortunately, it is too fragment*! for classification. Mr. A. hmitn-
Woodward has described it in the Ann. & Mag. Nat, Hist. ser. 0,
vol. xii. 1893, p. 397, pi. xvii. fig. 4.
Evidences of recent glacial action are entirely wanting ; but
Dr. Sutherland has noted ice-scratchings, etc., on the surface ot
the rocks underlying the Dwyka Conglomerate at Durban, and
possibly ice may have played some part in the creation of tne
Dwyka Conglomerate. Ice is looked upon as the principal agent
in the removal of so vast a quantity of the sedimentary strata as
that now missing in South Africa by those who are in favour of a
'glacial period ' having extended over the earth at some pme ot
its existence; but the total absence of moraines, erratics, and other
evidences of glacial action must be accepted (aa against vague
theories) in support of the arguments which tell against the
glaciation of the southern portion of the continent since the close
of the Jurassic period.
I cannot imagine glaciers descending from the peaks of volcanic
rock without bearing boulders of the characteristic rock of that
series, and these would be deposited in the lower-lying valleys, l he
absence of such boulders is strong evidence against any such glacial
theory. On the other hand, the softness of the rocks of the
horizontal strata, and the great amount of weathering to which they
have been subjected, in a climate with so variable a temperature as
the south-eastern portion of the continent possesses, would account
for the non-existence of any ice-scratches or markings.
The numerous 4 pans ' that are found all over South Africa have
been advanced as evidence of glacial action; but here, again,
other evidence is entirely wanting. 'Pans* exist in South Africa
at all elevations, and in rocks of all geological periods — on plains,
in valleys, on the High- veld plateau, and on mountain-tope; in fact,
almost every flat-topped hill in South Africa has a * pan * or small
lake on the top of it. They appear to be the result of the disinte-
gration and dissolution, by chemical means, of the rock-forming
constituents of the strata.
Various products from the rocks in the neighbourhood are
Rcncrally found on the lower (or outlet) side of these pans — limonite,
kaolin, and clay-beds, derived from the destruction of the igneous
Digitized by Google
H
(-
•<
< as
as -
£ ?
6
Vol. 50.] OF SOUTH-EASTERN AFRICA. 559
rocks, which generally exist near these pans ; but there arc no signs
of any rounded pebbles, nor any moraine-material, such as would
denote the previous glaciation of the area in which they occur.
IV. Supplemental Notes on the Dwyka Conglomerate.
Before closing this paper I wish to place on record a few facts
with regard to the Dwyka Conglomerate, which will perhaps tend
towards proving that it is not a glacial deposit, similar to the
Boulder-clay of Europe and America.
lstly. It is undoubtedly stratified.
The following is a section observed by mo at the farm ' Alpha;
about 12 miles east of the town of Vryheid (Zululand) : —
Molteno Beds at the top.
Beaufort Beds. } , on r^*
Ecca Beds. j 130 feet
— Distinct line of di vision.— Feet.
Shaly. Fragments isolated and few 4^
Hard Rock. Fragments large and numerous 10
Hard Rock. Stratified; fragments in layers 20
Hard Rock. Stratified ; without fragments 4
Grey Shaly Rock. Fragments numerous 3
Orey Indurated Shale. No fragments 5
Grey Indurated Shale. Fragments numerous and of
medium size 0 ^ 138 feet.
Blue Laminated Shale. No fragments 40
Bluo Indurated Rock. Fragments large and numerous . 10
Blue Indurated Rock. Numerous small fragments in
lines and layers 20
Grey Shale with wary laminations. Without fragments. 6
Blue Hard Rock. Fragments numerous and of medium
sue 10^
Blue Hard Rock. Fragments clustered together, and
of medium sire : thickness undetermined.
This section scarcely convoys the impression of a Boulder-clay.
The fragments of older rocks included in the Dwyka Conglomerate
consist principally of granitic rocks, also quartzites, shales, schists,
and other rocks dorived from the Malmeshury and Basement scries,
and numerous fragments of conglomerate (* banket ') — similar to
that now being worked for gold at Johannesburg, derived from the
Table-mountain series. The fragments are all more or less rounded,
but rarely quite round or oval in shape. As previously mentioned,
I failed to find any trace of ice-scratching on any of the fragments
of older rock in the Dwyka Conglomerate.
2ndly. The Dwyka Conglomerate thins out rapidly northward
against the older rocks. If it had been a glacial deposit derived
from the high land of the central portion of South Africa, the
deposit would have been thickest near that part of the mountains
from which it descended. The contrary is the case, however ; it
thickens away from them.
3rdly. The general horizontality of the beds is evidence against
any glacial theory.
4thly and finally. The matrix, when microscopically examined,
Digitized by Google
THE GEOLOGY OF SOUTH-EASTERN AFRICA.
[Nov. 1894,
shows in a marked manner the characteristics of a volcanic ash (see
above, p. 555) ; and when the matrix is reduced to powder, and
pressed into clay, it does not show the sticky, plastic nature of a
glacial clay, but is sandy and friable.
Rote. — In the section just described, each distinct layer was seen
to be separated from the one next above by a clear line of division.
EXPLANATION OF PLATES XXII. & XXIIL
Plate XXII.
Fig. 1. Diagrammatic section of the Drakensberg and the High-veld plateau.
(Approximate distance = 390 miles.) This shows the sedimentary
deposit* Wing horiiontally in relation to the igneous and Primary
rocks. The Dwykn, Ecm, and Beaufort Beds are seen to thin out
northward, while the Molteno Beds thicken in the same direction.
The Primary aud Basement-rocks underlying the Dwyka Conglomerate
are in all probability continuous from the coast to the Klip Stapel and
beyond, as they appear in all tbe deeper valleys on the eastern flank
of" the Drakensberg. At Lang's Neck the coal-seam in the Molteno
Beds suddenly drops from 5600 to 4000 feel above sea-lerel, a drop
which no doubt indicate* a considerable fault
Fig. 2. Diagrammat ic section from the Mont-aux- Sources on the Drakensberg to
St. Lucia Bay, on the East Coast (Approximate distance =220 miles.)
Plate XXIII.
Section from Hartebeest-Fontein in the Transvaal to Vredefort in tbe Orange
Free State, partly based on Dr. Molengraaf s researches. (Approximate
distance = 50 miles.) The lower portion of tbe sandstone (A) includes
beds of boulders, consisting principally of masses of gold-bearing con-
glomerate. The breccia (B) consists" chiefly of irregular fragments
of shale, quartxite, and sandstone, similar to Nos. 1, 2, and 3 ; and it
denotes the existence of a great fault, and downward displacement
nnd disappearance of the strata between the granite and the dolomite.
The Table-mountain Sandstone contains auriferous conglomerates in
its middle portion as well as in the upper (' Black Reef) series : and
the pebbles are larger in the former than in either the upper or lower
beds. Tbe section at De-Wette Drift, Yaal River, about 12 miles
south of Potchefstroom, is conclusive as to the position of tbe dolomite
with respect to the overlying and underlying rocks, which are nearly
vertical at this point, and clearly exposed in the river-bed.
[For the Discussion on this paper, see p. 5C4.]
Digitized by Google
St.
< —
Cnturt Belt
Fig 1.
Dl AGR AMMATI C
Section or Drakensbero ano
ABOUT 390 MIL*!
Terr-ate
Columttar lit J tribe
Bed*
Beauitrt Beds
X . . \lnlteew <f vtktr \«d*
Z . Table Maintain Sort
Wit dark litie.s in the MclUfw Itetfo iruit*
S W
(tar .'',in,L (. 1,1
Hnmsntith
Oraiuje, Free StuJe
Bill ccvereA jiluteau of Ih-aketi^berq (I) x- - Mitjh -Veltl
Ccltuttnur
>CT^ I)t,UriU
W K*
Drakmjherg <-
Dnutuu/t of the Mont
tkwttf* River
The Terra* e
Vitllev rf Ufiftn
Tutftfa Rveer
Mr
Vail.
(rlnrmnar
IhJenU
Tnn Bed?
*BOUT 220 MH.EB
FROM W TO E .
Sen - ftvrl
Mahne.<bt,r\ Ht<k
1,1.1.1 teal .srtinu* t*< Mclleiie Hedf
Diagrammatic Section from the Mont-aux-Sources. Dra
about 220 w
i- !>• <i.. Mmtcrrv Bnus.
Digitized by Google
Quart. Journ Geol . Soc . Vol . L . PI . XXil
High-Veld Plateau
s.
ttli-m^berq (it)
11. i '(>o a
N.W
tL'U'ru- crv CmMALm wiltv scfiists
4itr the knewii roal d*f>osit*<
jtlateuu (c)
IM.E .
* < 77i* M Be&
/ of Buffalo ffim
Moltetio HetL*
/ i 4 a /!n/,.
ha- (nail — — , laLlt iiu antnm,
m~ JL'°*^. \. M —J
I All
ratiqt
Itptrtnj
enSBErg, to ST Lucia Bay on the East Coast.
LES
Digitized by Google
Section or the Strata from Hartebeest-Fonteiim
About 50 M,
( Partly based oim
W
.4. <^€intlfttmt . tfr^ttx' .
1, Gneiss d Srhi.-
3 . Ltmrer Prriuit <
4 TuhUtnruMait
.5 fyntftur Rrflt.'.
ti. Am\gtLJr>idul
Hlriksdvrfi
7 . Cttfter Serif.* of thr LtlA< minnUtift
8 . Dvlomitt • Oliphmtt Klip cr'El'fh*
9 [Udl Shalt & (fitaiizUe * Quati-:itr
W httrf Tahiti d Iynecu.* Rcckf.
11 Gtry .ShtiU
5 .WW fnwufr
<■ DOLOMITE >
dt Wrtt, dnft
Ytutl Hivtr
/ . '///. ;.
I f ■ /•
w
JC
/ i.
D i):-LitJff At'.
Digitized by Google
Quart .JoiirnAjeol. Soc.Vol.L PI. XXI. I.
n the Transvaal to Vredefort in the Orange Free State.
es from West to East.
r mounoraap's researches.)
:i 4 3 4 3
itr-k -tchwrd B Bret fin .
♦
■
Tuhlr-m.flUitta.ru fandstr>ne-
'i rrttAtitif , In let xu I aled hrd
Syruimn] .•Ln'.«
* 4 .5 j / 5
cc-z. Bros Itth
Digitized by Google
Vol. 50.] OCCURRENCE OF DOLOMITE IN SOUTH AFRICA. 561
36. The Occurrence of Dolomite in South Africa.
By David Draper, Esq., F.G.S. (Read May 23rd, 1894.)
[Platb XXIII.]
Ma, W. H. Penning, F.G.S., examined a certain rock near Lyden-
burg, when in company with Mr. A. C. Crutwell, and they
described it in the Quart. Journ. Geol. Soc. vol. xli. (1885) p. 576,
as "a peculiar blue, fine-grained, calcareo-siliceou9 rock." This
they named " 4 chalcedolitc,' in consequence of the chalcedonic texture
frequently displayed — indeed, some portions of the rock are true
chalcedony. . . Sometimes it occurs in amorphous masses, weathered
to a grey colour, and to a peculiar, rough, trachyte-like surface ;
but mostly in thin beds, 2 or 3 inches in thickness, with earthy
partings."
Mr. Penning in another contribution, Quart. Journ. Geol. Soc.
vol. xlvii. (1891) p. 456, mentions the same roek (chalcedolite) as
immediately overlying the * Black Reef series ' of what he calls the
Megaliesberg Beds.'
Mr. C. J. Alford, F.G.S., in his 4 Geological Features of the Trans-
vaal,' 1891, mentions the occurrence and peculiarities of this rock
as follows : —
Page 3. Referring to * alluvial deposits,' he states : — 44 In several
places deposits of a fairly pure crystalline carbonate of lime are met
with, those in the vicinity of the Six-mile Spruit, between Pretoria
and Johannesburg, being some of the most remarkable ; these appear
to result from the disintegration of a hard blue quartzite plentifully
veined with lime, which occurs in the neighbourhood."
Page 6. 44 The metamorphism of these beds [4 schistose rocks
where in contact with, or adjacent to, the irruptive rocks, results
in several somewhat complicated products ; amongst others the cal-
careous quartzite before mentioned, which in some places passes into
dolomite, and on exposure to atmospheric influence yields up its
lime and becomes, on the surface, altered into a species of chert.
This calcareous quartzite is locally known as elephant-rock; from the
resemblance which its weathered surface bears to the hide of that
animal. In other places, as on the hill near the junction of the
Olifants and Blyde rivers, it has resulted in very calcareous beds of
granular quartzite, bearing in structure a marked resemblance to
dolomite, in some of which the siliceous and calcareous matter
has assumed a peculiar banded arrangement."
And finally, at p. 25 : — 44 In the neighbourhood of Wonderfontein
and in other places, the erosion of the exposed surface of the altered
sandstone has produced very peculiarly weathered rock-masses, and
the underground watercourses have resulted in the formation of
many a series of extensive caves, the tortuous windings of which
can be followed for a long distance, and which form the underground
Digitized by Google
562
MR. D. DRAPES Olf THE OCCURRESCE OF [Nov. 1 894,
course of the Mooi River. In the calcareous quartzite before alluded
to the river has, in course of time, worn for itself a subterranean
course by dissolving out, in the first instance, the little veins of
calcite, aud then, when increasing volume gave it greater strength,
the quartzite also, the lime being again deposited as stalactitic
formations in the caves Some parts of these quartzite beds
are sufficiently calcareous to produce on calcination a valuable
lime."
From these extracts from their writings it will be seen that both
Mr. Penning and Mr. Alford have described this rock from the
peculiarities that they have noticed where they examined it in situ.
Mr. Penning named it 4 chalcedolite, in consequence of the chalce-
donic character frequently displayed.' Mr. Alford calls it a 4 cal-
careous quartzite,' passing into dolomite, and superficially 4 altered
into a species of ohert.'
Having had especial opportunities of examining this rock, especially
several deep workings in it in the Malmani district, I have come to
the conclusion : —
lstly. That the 4 elephant- rock ' occurring in various parts of the
Transvaal, but principally in the Potchefstroom, Lichtenburg, Mal-
mani, and Lydenburg districts, is really a dolomite, with thin
interstratified siliceous bands, for the following reasons : —
(a) Its composition is
48 per cent, carbonate of lime,
48 per cent, carbonate of magnesia,
4 per cent, silica,
(o) That tho residue, after the limestone has been removed by
the atmosphere, is a dirty-brown, soft, earthy matter similar
to manganese oxide. This occurs in all the caves, and in
between the siliceous layers, where it has been long exposed
to the weather.
(c) That the bulk of the rock is of the composition previously
mentioned (a), the bands of siliceous material being not
more than 10 or 15 per cent, of the whole mass where it has
not suffered from atmospheric influences. That the 4 debris '
from the rock consists largely of fragments of the siliceous
bands, strewn about on the surface, I admit ; but this only
occurs on the surface, and is tho result of a large amount of
the calcareous portion of the rock having been removed.
I submit that the alteration of a 4 calcareous quartzite
into a 1 dolomite,' and this again into a 4 species of chert,' is,
to say the least of it, unique.
2ndly. That this rock is interstratified between the Table-mountain
series (in which the conglomerate-beds of the Transvaal are situated)
and the quartzites of the Gats Rand (the 4 quartzites of the
Zuurberg' of liain) ; and in proof of this assertion I submit a section
(PL XX1I1.) taken by Dr. G. A. F. Molcngraaf, Professor of Geology
in the University of Amsterdam, and myself, from Hartebeest-Fontein
Digitized by Google
Vol. 50.]
DOLOMITE IS SOUTII AFRICA.
5G3
to Vredefort. This section shows the * dolomite ' in its true position
with regard to the other rocks. A section from Pretoria to Vrede-
fort (south) would show a similar occurrence of the several strata.
In 1 Petcrmann's Mittheilungen,' vol. xxxiv. (18SS)p. 227, 1 find
the following description of this rock by Dr. A. Schenck : —
" A characteristic rock which accompanies the strata of the Kuap
Formation throughout South Africa, and here and there extends over
a wide area, is a peculiar, blue-black, dolomitic limestone. It occurs
both on the Huib aud the Han-ami plateaux in Great Namaqualand,
and also in Griqualand West, where it forms the so-called Kaap
plateau, west of the Vaal, and extends from thence over a great part
of Bechuanaland anda great part of the Western and Central Transvaal
(Marico, Lichtenburg, Wondcrfontein). Farther off it appears also in
the Northern Transvaal, and on the Drakensberg (Pilgrims' Rest,
Spitzkop, Krokodil River)."
In the geological map, pi. xiii., accompanying Dr. Schenck's paper,
the position of the dolomite is marked ; and it appears to be of great
extent, especially in the Transvaal and Namaqualand.
In the Malmani district of the Transvaal the dolomite is intersected
by numerous fissure-veins of quartz, bearing gold ; but, owing to
the immense difficulty experienced iu draining the mines, the district
has been abandoned by the gold-miners. It was found that under-
ground channels of communication existed between the various
streams and pools in the neighbourhood, and all attempts to free
the mines from water proved abortive.
Lead, zinc, cinnabar, silver, gold, and other metals have been
found in small quantities in the quartz-veins and pockets in the
dolomite at Malmani, and at Lydenburg the same rock is being
worked for gold.
In the Malmani district numerous large holes occur in the dolomite ;
some of these are of great extent ; for instance, the * Baviaan Gat,'
near the village of Otto's Hoop, is about 100 yards in diameter at
the surface, narrowing to about 60 feet in a depth of 120 feet, and
at that depth is a pool of water 105 feet deep. These holes, « Wonder
Holes ' they are called locally, have been caused by the disintegration
of the rock by natural causes, and the eventual sinking of the
surface-ground or roof, when too thin to support its own weight.
In one cave near Otto's Hoop the roof has fallen in and the trees
which grew on the surface are now found growing at the bottom of
the cave.
Mr. Francis Galton, in his 'Tropical South Africa,' p. 200,
describes water-holes similar to those at Malmani, as occurring
at Otchikoto and Oriejo ; and, judging from his description, it
would appear that the dolomite occupies a large area in Ovampoland.
Recent descriptions of the great caves in Mashunaland, and of the
rocks in which they are situated, lead to the supposition that this
rock extends to the neighbourhood of the Zambesi River.
It will therefore be seen that it occupies an important position in
the geology of South Africa, and is worthy of more thau a passing
notice.
Q.J.G.8. No. 200. 2 b
504
MB. D. DRAPER ON THE OCCURRENCE OF [Nov. 1 894,
I have written this short communication in the hope that those
who have the opportunity of studying the geology of South Africa
will in future give particular attention to the 4 dolomite/ if they
happen to come across it during their travels.
In conclusion, I wish to record some ohservations that I have
made during my travels in South Africa (extending over a period of
thirty years), with regard to the surface-deposits of limestone-tufa,
now occupying large areas in the drainage-basin of the Vaal and
Orange rivers, and its relation to the dolomite. These beds of
travertine are found only on the surface, dotted about the country,
sometimes over small areas, but occasionally, as in the districts of
Hope-Town, Boshoff, and Jacobs vaal, and in Griqualand West,'
covering almost the entire surface of the country.
I have never found this tufaccous limestone except in such positions
as to render it highly probable that the supply of lime required for
its formation was derived from the dolomitic rocks of the Transvaal
or of Griqualand West.
These surface-deposits of carbonate of lime occur at a lower level
than the dolomite of the Transvaal, and are never found higher than
that rock. Those portions of the Orange Free State and the Trans-
vaal that lie higher than the dolomite are devoid of the limestone-
tufa ; and the soil of Natal, where the dolomite has not been dis-
covered, is so devoid of calcareous matter that wheat will not yield
a crop without the application of lime to the arable land.
The waters flowing from the dolomite of the Transvaal contain
so great a quantity of lime that deposits occur wherever they become
stagnant ; and the miuing town of Johannesburg rejected a scheme
for supplying the town with water from Wondcrfontein, on account
of the quantity of lime held by that water in solution.
[For the Explanation of Plate XXIIL, see p. 560.]
Discussion (on the preceding two Papers).
Mr. Rutlet said that the paper on 'The Occurrence of Dolomite
in South Africa ' was especially interesting, as it appeared to afford
a remarkably good instance of the replacement of limestones by
silica, a point which he had already dealt with in a paper recently
read before this Society, and in which one of tho examples cited
was a calcareous, gold-bearing quartzite from Nondwcni in Zululand.
Mr. Draper's suggestion that the extensive beds of calcareous tufa
in South Africa were derived from tho waste of the neighbouring
dolomites, coupled with the occurrence of chert in those rocks and
their graduation into quartzites, seemed to make up a very com-
plete account of the changes which these calcareous beds had under-
gone. The occurrence of detached nuggets and groups of crystals
of gold in a talus on a hillside might perhaps be due to the gold
having originally occurred in limestone, whioh had been subsc-
' [See O. W. Stow, Quart, Journ. Geol Soc vol. xxx. (1874) pp. G15-4J17.—
T. B. J.J
Digitized by Google
Vol. 50.] dolomite nr SOUTH AFRICA. 565
quently dissolved or partially disintegrated. In a microscopic
section of the Nondweni quartzite the gold appeared to lie chiefly
in the calcareous portions of the rock, although some of it was
distributed through the quartzite itself.
Mr. Nicol Brown remarked that the dolomitic limestone at
Pilgrims' Rest, which is apparently the * elephnnt-rock ' of Mr.
Draper, underlies all the country in the neighbourhood. The lime-
stone is eroded into valleys at Pilgrims' Creek and along the course
of the river Blyde and elsewhere. On the top of the limestone
lies a bed of manganiferous earth ; over this come the beds of
quartzite and chalcedolite represented by the specimens on the table,
and on the top of the whole there are frequently masses of diorite,
often decomposed.
Although the general dip of the strata is fairly represented by
about 1 in 13 to the south-west, the local folds and contortions aro
numerous, and when he commenced to study the district it was
almost impossible to follow the stratification. Numerous carefully
registered specimens were sent home, and from these the succession
of the rocks has been ascertained with some degree of certainty,
with this practical result, that the rich gold-bearing zono is found
to be immediately above the manganiferous earth.
Numerous sections of working-faces have since established the
succession. It may be noted, however, that there are distinct indica-
tions of the gold-bearing beds sometimes running into the limestone,
while sometimes the manganiferous earth overlios the gold-bearing
beds. On the escarpments very little chalcedolite and quartzite are
found detached from the hillside, but on the counter-escarpments
very large masses of these rocks are spread over the hillside, and it
is amongst these fragments on Brown's Hill that the nuggets
exhibited at the Meeting were found.
The thickness of the limestone is not known ; it has been eroded
500 or 600 feet in Pilgrims' Creek, but no bottom has been seen.
The rock immediately underlying it is unknown.
Prof. T. Rupert Jones referred to Mr. Draper's view of the Ecca
Beds thinning out, and the Molteno Beds thickening, northwards,
in Natal and Zululand, and alluded to a specimen of the dolomite
(exhibited by the previous speaker) from the Lydenburg district, with
its associated auriferous quartz : this limestone had been tested
and microscopically examined at the Royal College of Science, South
Kensington.
2h2
Digitized by Google
560 XB. H. WOODS ON THE IGNEOUS BOCKS [Nov. 1 89 4,
37. The Igneous Rocks of (he Neighbourhood of Builth. By
Henry Woods, Esq., M.A., F.G.S. (Read June 20th,
1894.)
Contents.
Pape
I. Introduction and Bibliography 5«>6
II. The Diahase-Porphvrite 567
III. The Andesires ." 569
IV. The Andesitic Ashes 571
V. The Rhjolitea 573
VI. The Diabases 574
VII. Conclusions 577
Geological Map of the District 508
I. Introduction and Bibliography.
In south-west Radnorshire a series of igneous rocks associated
with beds of Ordovician age stretches from near Builth in the south
to beyond Llandrindod in the north. This area is surrounded on
all sides, except the north-west, by Silurian rocks, and has a length
of about 7£ miles, and a width varying from 2 to 5 miles. The
best account of the geology of this district is that given by Murchison
in the ' Silurian System.' Short descriptions or notes have also
appeared in memoirs and papers by De la Beche, Phillips, M'Coy,
Ramsay, Symonds, Lapworth, and liutley. The district is shown
on sheets 56 S.W. and 56 S.E. of the Geological Survey, and was
mapped by the late Sir Andrew Ramsay and by Mr. W. T. Aveline ;
the maps were issued in 1850, and were explained by two horizontal
sections on Sheets 5 and 6, but no descriptive memoirs were
published.
The following is the literature relating to this area of Ordovician
and associated igneous rocks : —
Murchison, R. L— 'The Silurian System ' (1839), pp. 314, 324-335, pi. xxxiii.
figs. 5-7.
Mcrchibon, R. I.—' Siluria,' 5th ed. (1872) pp. 59. 81.
Db la Bf.ciie, H. T.— 4 On the Formation ot the Rocks of South Wales and
South-western England,' Mem. Geol Surv. toI. i. (1846) p. 22.
Phillips, John. — ' The Malvern Hills/ etc., Mem. Geol. Surv. vol. ii. pt i.
(1848) pp. 227-315, 327.
M'Coy, F. — ' British Palaeozoic Fossils ' (1852), pp. 354, 369, 373-74. [Lists of
fossils.]
Ramsay, A. C, H. W. Bribtow, H. Baukrman, and A Geikie.— ' Catalogue of
the Rock Specimens in the Museum of Practical Geology,' 2nd ed. (1S6U)
pp. 112, 197, 211.212, 248.
Symonds, W. 8.—' Records of the Rocks/ 1872, p. 93.
[Newton, E. T.] — 'A Catalogue of the Cambrian and Silurian Fossils in the
Museum of Practical Geology/ 1878, pp. 23-29. [Lists of fossils.]
Lapwokth, C— Ann. & Mag. Nat. Hist. sop. 5, vol. iv. (1879) p. 339.
Rctlry, F.— • The Felatic JUvaa of England and Wales/ Mem. Geol. Surv
1885, p. 20.
In the present paper I propose to deal with the igneous rocks of
the southern half of this district — that lying between the town of
Digitized by Google
Vol. 50.]
OF THE NEIGHBOURHOOD OP BU1LTH.
507
Builth and a line drawn from Cwm-amliw, eastward to Garth,
and then round the Castle Bank ; and shown in the accompanying
map (p. 568). The rocks met with are diabase-porphyrite,
andesite, andesitic ash, rhyolite, rhyolitic ash, and diabase. These
give rise to characteristic hummocky ground, with here and thero
a few prominent peaks, forming a marked contrast to the regular
features of the neighbouring Ludlow escarpment. A good example
of the scenery of the district is given in the * Silurian System '
(plate facing page 330), from a drawing made by Lady Murchison.
II. The Diabase-Porphtbite.
This is the most conspicuous rock in the district ; it consists of a
dark-coloured, fine-grained base, much decomposed, containing
numerous light felspars of largo size, and often having a greenish
tinge; in some cases these porphyritic felspars become much
smaller. The diabase-porphyrite occurs in four masses, extending
in a north-and-south direction, and is intrusive in the andesites and
andesitic ashes, possibly in a laccolitic form. The first of these,
commencing in the south, forms the central part of the tract known
as tho Llanelwedd Rocks, extending from the Hock House nearly
to Carneddau Farm, and is surrounded, except on the south, by
andesite. Tho second, which is more irregular in form, occurs to
the north-east of Carneddau Farm, and is intruded into the
andesite. Tho third is the smallest mass, and forms the eastern
part of Caer Fawr, which reaches a height of 1267 feet. Tho
fourth is the largest, and extends along the western part of the
Carneddau Hills for a distance of a little over a mile ; it is intruded
into the andesite and andesitic ash.
Under the microscope the earlier plagioclase-felspars in this rock
are seen to be considerably decomposed ; the base consists of small
plagioclase-felspars and augite, with some, and frequently much
pale green chlorite. In a few cases, as for instance in a specimen
from near the Kock Houso, the augite has entirely disappeared, the
base being composed of felspar and chlorite, lime ui to and leu-
coxene are often present. Frequently there are large irregular
vesicles filled with chlorite or calcite. In some sections the later
felspars are markedly lath-shaped, but they do not exhibit any flow-
arrangement.
The silica percentage of the diabase-porphyrite is 48-36, and its
specific gravity 2*78.
On the Geological Survey map (56 S.W.) a continuous mass of
* greenstone ' is shown, extending from Llanelwedd Church north-
wards, to near Cwm-amliw ; this was probably intended to
represent the diabase-porphyrite, since on the horizontal section
(Sheet 5, No. 1) it is spoken of as * greenstone porphyry,' but it
includes, in addition to the diabase-porphyrite, a considerable area
of andesite and andesitic ash.
Digitized by Google
Vol. 50.]
IGNEOUS ROCKS NEAR BUILT!!.
III. The Andesites.
Tho andesites aro widely distributed in this district ; there are
four areas, which will be described in tho following order: (1)
surrounding the three southern masses of diabase-porphyrite ;
(2) around the northern part of the largest mass of diabase-porphy-
rite; (3) north of Gclli-Cadwgan ; and (4) extending from Cair
Einon to Llwyu-Madoc, except where broken into by the diabase
near Cwm-bcrwyn.
(1) The andesite between Llanelwedd and Carneddau Farm, on
the west of the Llanelwedd diabase-porphyrite, forms a well-marked
type : it is, when fresh, a dark-green compact rock, and on a
weathered surface shows a thin white crust. Good specimens may
be collected at between ^ and £ mile north of the Rock House ; in
these, crystals of felspar and augite may be seen with the unaided
eye. Under the microscope, sections show a gronndmass formed
mainly of minute felspars, exhibiting in places flow-structure : in
this porphyritic pi agioclase- felspars occur ; they are rather decom-
posed, and sometimes contain irregular inclusions of the groundraass.
Augite is also rather abundant ; it is colourless and quite fresh.
A pale green, rhombic pyroxene, showing distinct pleochroism and a
slightly fibrous structure, is fairly common ; it is probably an altered
enstatite. Ilmcnite associated with leucoxene is present, and also
small crystals of magnetite. The silica-percentage of this rock
is 50*8 and its specific gravity 2*74.
The andesite on the eastern side of the Llanelwedd diabase-
porphyrite differs considerably from that on the west just described :
it is much more decomposed and of a dull greenish colour. Under
tho microscope it is seen to be formed of porphyritic plagioclasc-
felspars in a base of minute felspars ; there is very little augite,
and enstatite is absent ; chlorite is abundant, and there is a little
calcite. The rock has a specific gravity of 2*702.
The andesite, extending north of the Llanelwedd diabase-
porphyrite up to the southern bordor of the largest mass of the
same rock, is green or greyish in colour, sometimes light, some-
times dark; the felspars in many casos are seen as glistening
lath-shaped crystals, in others they are milky-white and rather
irregular. Sections show that the groundmass of the rock is made
up of a brownish isotropic material containing numerous small
felspars generally having a flow-arrangement ; sometimes there are
also irregular granules of a semi-opaque substance. The phenocrysts
consist of plagioclase-felspar, and, in some slides, of an altered
rhombic pyroxene : augite is rare and often absent.
This same -mass of andesite is continued southwards by Cacr
Fawr down to the Big Wood. A section from the south-western part
of Caer Fawr is similar to those just described, but is more decom-
posed and contains much chlorito : another from tho southern part
of the Big Wood shows a particularly good flow-structure in the
later generation of felspars, and also contains a large quantity of
calcite.
Digitized by Google
570
MB. H. WOODS OX THE IGNEOCS UOCKS
[Nov. 1894,
(2) The second area of andesite surrounds the northern part of
the largest mass of diabasc-porphyrite. Specimens of this, from a
spot just south of Cwm-amliw and east of Url Wood, are dark grey
or almost black in colour, and one can distinguish with the unaided
eye felspars, calcitc, and a daik green mineral. Under the micro-
scope tho earlier plagioclase-fclspars arc seen to be very much
decomposed ; usually they have a length of about 3 mm. The
later felspars are very much smaller ; the groundmass contains, in
addition, a semi-opaque material, and a large quantity of magnetite,
the latter generally having the form of skeleton-crystals. Augite
occurs very sparingly, but not as a constituent of the groundmass.
Numerous large and often irregularly-shaped vesicles are present,
having a diameter varying from *7 to 2 mm. These in some cases
contain calcite in the centre, around which is a narrow band of a
I alo green mineral, probably dclessite, and external to this is a zone
of quartz. In other cases the vesicles do not contain calcite, but are
occupied by delessite with a border of quartz. At other times,
almost the whole of the vesicle is filled with caJcite, with here and
there a little quartz or dclessite at the margin. Quartz and calcite
also occur in the groundmass as secondary minerals. The specific
gravity of the rock is 2*77.
The rocks on the east of the diabase-porphyrite, which form the
main part of this area of andesite, are occasionally dark in colour,
but mostly light grey with sometimes a bluish or greenish tinge,
and generally showing crystals of felspar. A section from the
ridge immediately north-west of Penrubulla shows a groundmass
composed mainly of small felspars, containing porphyritic crystals of
plagioclase, which are considerably decomposed ; there is also some
secondary quartz. Similar features are seen in sections taken from
the ridge north-west of the last 1 a ' in Carneddau (and north of
Jt.M. 1322),' and from the ridge south-west of Carneddau House
aud immediately north of the first ' L ' in I JansantiFraid ; the first
of these, however, differs in containing a large quantity of secondary
quartz. Specimens from the ridge mile west of Carneddau
House were also sliced. In these the porphyritic felspars are very
large, and so much decomposed that the twinning is only indistinctly
seen and is sometimes quite absent ; not unfrcquently they have
been entirely replaced by secondary quartz. The groundmass of
the rock consists of a semi-opaque substance, and small felspars
more or less felted together ; it also contains some secondary quartz
and a little calcite. A few small vesicles containing quartz or
chlorite are present.
(3) The field-relations of the andesite north of Gelli-Cadwgan
are not very well seen, but apparently it is intrusive in the
Llandcilo Beds. The rock is quarried near its south-western
extremity by the roadside, and is used as road-metal ; it is compact,
of a light grey colour, with here and there dark streaks, and is
1 Theae are references to the 6-inch Ordnance Maps.
Digitized by Google
Vol. 50.]
OF THE NEIGHBOURHOOD OF BUILTH.
571
well jointed in a roughly cuboid a 1 manner. A specimen from this
quarry was found to contaiu 57*73 per cent, of silica, and to have
a specific gravity of 2*639. Under the microscope it is seen to be
formed of a base of small, rather irregular felspars, with a few
porphyritic crystals of plagioclase ; there is also some secondary
quartz. Other sections taken from specimens collected at different
spots between the quarry and Gauallt Wood ore similar to the
last, but the porphyritic felspars arc larger, and the smaller felspars
of the groundmass have more regular outlines and show a well-
marked flow-arrangement.
(4) The last area of andesite extends from Caer Einon in a
north-easterly direction to Llwyn-Madoc, a distance of a little more
than 2 miles ; but this is broken into by amass of diabase between
Cwm-berwyn and Cil-y-berllan.
Sections from various parts of Caer Einon show numerous rather
large porphyritic plagioclases, and a base composed mainly of small
felspars, generally with a good flow-structure, and containing
vesicles of irregular shape filled with a pale green, fibrous, chloritic
mineral. The same features were seen in a Bection from near
Bwlch-y-trawspen.
Another slice was cut from a specimen collected at a spot £ mile
north of Khiw-las and 70 yards east of the stream which runs to
Khiw-las ; this shows distinct evidence of crushing, tho felspars have
a parallel arrangement, and numerous bunds of quartz are present.
Limonite also occurs, sometimes showing eight-sided sections,
apparently as a pseudomorph after augitc.
Between Cwm-berwyn and Llwyn-Madoc I was only able to find
exposures near Gacr; the rock is here rather dark in colour, and
contains felspars, chlorite, and a small quantity of augite.
IV. The Andesttic Ashes.
A belt of andesitic ash extends from Llonelwedd to Orl Wood,
forming the western boundary of the volcanic scries, and being
overlain by Llandeilo Shales; just north of Wern-td its outcrop is
shifted by a dip-fault. When fresh the rock is of a light bluish-
grey colour, and has a gritty feel ; it is well exposed in numerous
quarries between Llanelwcdd and Wye Cottage, and is largely used
in the neighbourhood for building. Spocimens from these quarries
were found to have a specific gravity of 2*60 and a silica-percentage
of 51*10. Under the microscope, sections taken from Tan-y-graig
and othor quarries to the south show numerous irregular fragments
of plagioclase-felspar, cmbodded in a fine-grained base containing
chlorite and calcito ; some fragments of andesite are also present.
The lower part of the ash in some of the quarries, particularly
at Tan-y-graig, contains numerous well-rounded pebbles of
andesite ; they are usually 5 or 6 inches in diameter, but one
example I saw had a length of 2 feet and a breadth of 1£. Under
the microscope the pebbles are seen to resemble more closely the
Digitized by Google
572
MR. II. WOODS ON THE IGNEOUS ROCKS
[Nov. 1894,
andesitc on the east of the Llanelwedd diabase-porphyritc than
that on the west. The specific gravity of one of the pebbles was
found to be 2-5S, and the silica-percentage 51*6.
Fossils are not very common in the ash, but I have found several
specimens of Orthis calligramma, Dalm. M'Coy 1 also records the
following, which are preserved in the Woodwardian Museum : —
Crania divaricata (M'Coy), Ltptcena sericea, Sow., and Serpulite*
dispar, Salt.* In the third quarry south of Tan-y-graig I also
found specimens of what appear to be polyzoa. Dr. Gregory kindly
examined these, and he says that they seem to be allied to the
genus Drymotrypa. These species are not sufficient to fix the
horizon of the ash, but as it is overlain by Llandeilo Shales con-
taining Ogygia huchi, etc., it is probably of Lower Llandeilo age.
Fig. 1. — Section immediately south of Tan-y-graig.
On the Geological Survey map the ash just described is shown as
greenstone, but this appears to have been a slip in colouring, since
its nature is correctly indicated on the Horizontal Section (Sheet 5,
No. 1), where it is spoken of as ' Trappean Conglomerate* in the
first edition, and ' Felspathic Tuff and Conglomerate ' in the second.
In the lowest part of the quarry at Tan-y-graig, underneath the
andesitic ash, is seen a greyish rock with numerous white felspars,
resembling closely, in hand-specimens, the diabase-porphyrite already
described ; under the microscope, however, it is seen to be quite
different from that rock. It is composed of a fine-grained base con-
taining plagioclase-felspars of various sizes and usually of irregular
outline; some calcite and chlorito are also present. Although
my sections are not absolutely conclusive, I think there can be
little doubt that the rock is an ash: its silica-percentage is 61*44.
1 -British Palicotoic Fossils ' (1852), p. 373.
a The Rev. T. C. Davies, formerly of Builth, informs me that many year* ago
he found in the ash at Tan-y-graig a specimen of Asaphus tyranntut, and believes
that he gave it to Dr. Grindrod. No reliance, however, can be placed on
the determination of the species. On Horirontal Section No. 1 of Sheet 5
(Geol. Survey) there is written under the ash at Tan-y-graig * Asaphua latico*-
tatus* but Mr. E. T. Newton, F.R.S., informs me that the specimen is not in
the Museum of Practical Geology, and he thinks it must have come from the
Llandeilo Shales, not from the ash, since Salter, in his Monograph on the
Trilobites (p. 158), says that the only specimen known is a tail from the Llan-
deilo Flags of Maen Goran, near Builth.
[Scale: I inch = 880 feet]
« = Andesitic ash.
b = Andesite.
c — Diabase-porphyrite.
d = Diabase.
e = Llandeilo Shales.
Digitized by Google
Vol. 50.]
OF TOE NFIGHDOrRnoOD OP BUILTH.
Another area of andesitic ash stretches from just north of Caer
Einon and Caer Fawr to near Penrubulla. In hand-specimens this
is sometimes dark in colour, but often light grey or bluish, and
occasionally ehows distinct white felspars : in some cases, as for
instance near the northern diabase-porphyrite, it is mixed with a
certain amount of sedimentary material, and is well stratified.
•Sections taken from the three following spots are almost iden-
tical:— (1) 140 yards north-east of Penrubulla; (2) the *Camp'
west of Cwm-berwyn ; (3) 4 Old Quarry ' east of Newmead Farm ;
these show numerous fragments of plagioclase-felspar of various
sizes and usually irregular in outline ; the groundraass contains a
large quantity of a yellowish-green chloritic mineral and a fair
amount of secondary quartz, the latter sometimes replacing the
felspars. In some parts of the slides there arc groups of very
small (usually oval) vesicles with dark borders, and containing the
yellowish-green chloritic mineral, or, occasionally, quartz. A few
small fragments of andesite are also present. Another slide from
just north-west of Caer Einon is similar, but the rock is more
decomposed and contains a large quantity of calcitc. A section
from a little more than | mile north of the summit of Caer Einon,1
and another from \ mile north of Bwlch-y-trawspen and \ mile
south-south-west of the * Camp,' differ from those just described
in containing very little chlorite, and in the felspars being larger
and more numerous.
There is a small area of ash just south of Big Wood ; in its
southern part this is dark in colour and rather coarse, but north-
wards it becomes lighter and finer-grained. A specimen collected
at 70 yards south of Big Wood is very similar to those described
above from Penrubulla, etc., except that it contains very few vesicles.
A section from the southern part of Big Wood (almost due west of
Macn-cowyn) differs in having the felspars much smaller ; in another
from \ mile south of Big Wood, small elongated vesicles are very
numerous in some parts of the slide.
V. The Rhtolites.
In this district the rhyolitic rocks cover only a small area ; they
occur as isolated patches between Maen-cowyn and Penrubulla.
In hand-specimens they are usually compact and of a dark grey
colour, or, when weathered, yellow or white, and often contain
porphyritic felspars. Some of theso rhyolites may possibly be
intrusive.
A section from a specimen collected 1 mile south-south- west of
1 At a spot \ mile north -north -west of the summit of Caer Einon, I found
a large block of black chert ; it was not in situ, but I think it could nut
have travelled more than a very abort distance. Under the microscope this
chert is remarkable for the large size of the wponge-spicules which it contains,
some of them being 5 mm. in diameter. Dr. Ilinde kindly examined the slides,
and he inform* me that the spicules belong to the anchoring-ropea of hexacti-
ncllid sponger, and that there is a piece of Llandeilo Shale from near Bui lib.
in the Museum of Practical Geology containing similar spicule*.
Digitized by Google
574
MR. H. WOODS OK THE IGXEOU3 ROCKS
[Nov. 1894,
Maen-cowyn shows under the microscope a cryptocrystalline ground-
mass, with here and there small microcrystalline patches. The
porpbyritic felspars are twinned on the albite type, sometimes
combined with the Carlsbad or with the pericline type. The other
slides differ from this chiefly in the relative proportions of the
cryptocrystalline and microcrystalline material in the groundmass.
In some sections there are bands of quartz. Spherulitic structure
has not been met with in any case.
The rhyolite has been found to be nodular only at one spot,
namely, i| mile east of Newmead Farm, and a little more than
£ mile north of Caer Einon. The nodules stand out on a weathered
surface of the rock, and can bo easily detached ; as a rule they are
very irregular in form, and of small size, sometimes being 2 inches
in diameter, but often less. They aro solid throughout, and in
section are seen to be formed of microcrystalline quartz and felspar,
and to show no trace of either a radial or concentric arrangement ;
in fact the structure does not differ from that of the groundmass
of some of the ordinary rhyolites. The silica-percentage of one
nodule was found to be 72*1.
lthyolitic ashes have been met with at the following spots : —
Immediately north of Maen-cowyn ; north of Caer Fawr ; at ^ mile,
and also at a little more than £ mile west of Cwm-bcrwyn.
VI. The Diabases.
The diabases are of later date than the rocks previously described,
and may therefore conveniently be considered last. They are all
intrusive in the Llandeilo Shales, and are found on the east and
west of the main volcanic series. The minerals which occur in the
diabases are plagioclasc-felspar, augitc, magnetite, ilmenite,leucoxcne,
apatite, chlorite, and secondary quartz and calcite. The plagioclase
is generally much decomposed, and the augite in most cases ophitic
On the west, between the town of Builth and Pen-cerig, there are
four sills of diabase. The northernmost stretches from Pen-cerig in
a south-westerly direction for about | mile. It is well exposed in
the quarries at the north-western edge of Pen-cerig Wood, and at
Pen-cerig Lake ; also in the road-cutting at the back of Pen-cerig
House (fig. 2, p. 575). At the two last-named localities the junction
with the Llandeilo Shales, containing the following fossils, is seen :
Ogygia buchi (Brongn.), Ampyx nudus (Murch.), Trinucltu* Jim-
briatus, Murch., Barrandia cordai, M'Coy, Siplionoireta micula,
M'Coy, etc.
The rock in the quarry at the north-west of Pen-cerig Wood is a
medium-grained and rather decomposed diabase, having a specific
gravity of 2*75. The augite is colourless, and occurs in ophitic
plates. Leucoxene forms large grains and is often associated with
ilmenite.
The rock at Pen-cerig Lake is finer-grained than the preceding,
and in hand-specimens differs considerably in appearance. The
microscope shows that the augite is usually scarce, and in one slide
Digitized by Google
Vol. 50.] OP THK NEIGHBOURHOOD OF BUILTH. 575
entirely absent, its place being taken by chlorite. There is also a
large amount of secondary quartz and calcite.
In the road-cutting at the back of Pen-cerig House the rock
resembles, in hand-specimens, that of Pen-cerig Wood. At the
junction of the diabase with the Llandeilo Shale, the latter is, for a
space of 3 or 4 inches, converted into a hard, grey, porcellanous
rock ; beyond this it does not differ from an ordinary black shale,
Fig. 2. — Section seen in the road-cutting at tlu bad' of
Pen-cerig House.
rVv. ....I;;..... ..... • • »
. ....... ......... .♦♦»»-
I ». ♦«♦♦•♦» »•*♦♦»♦♦
g». .♦♦♦■»».♦ *.♦♦»»!• -
... ♦♦!.♦♦♦♦»» «o
& — tt • K» ♦«.♦♦»♦*.*•
♦ ♦ ♦ J> *>y ♦ ♦ ♦ I • ♦ ♦ *>.*
♦ . ,\« *
..♦».».♦.♦.♦»♦*••«♦
LevtUfRoad
[Length of section = about 18 yards.]
a = Llandeilo Shales. 6 = Diabaee.
c = Junction of shale and diabase, obscured at this spot.
except in being somewhat more indurated. A section of a junction-
specimen shows that the line of division between the two rocks is
well defined. The igneous rock has become very fine-grained,
consisting of minute felspars and chlorite ; some secondary quartz is
present, and a large amount of calcite. Tho shale next the diabase
shows a fine-grainod groundmass in which occur what appear to
have been cavities, some of which are now filled with quartz,
others with a pale-green chloritic mineral, often possessing a radiating
fibrous structure. There are also large irregular patches of calcite.
In Harper's Quarry,1 | mile south-west of Pen-cerig House,
the diabase is seen on the southern side above tho Llandeilo Beds ;
the latter are altered into a hard, compact, and well jointed rock,
hsving a black or light grey colour. The igneous rock is rather
fine-grained, and consists of the usual minerals, but the augite is
now represented by pale green chlorite ; and there is a large amount
of a semi-opaque material and calcite.
The western sill, the smallest of the four, extends from just north
of Gwern-y-fed-fach across the Wye to Park Wells. It is exposed
near Gwern-y-fed-fach, in the bed of the Wye, in a quarry at Park
Wells, and in a road-cutting north of Park Wells, where the
junction with the Llandeilo Beds is seen. It is rather a fine-
grained greyish rock : a section of a specimen from north-west of
Gwern-y-fed-fach shows tho plagioclase to be rather less abundant
than usual, but very much decomposed ; the augite is clear and
colourless, and occurs in ophitic plates extending over large areas
and enclosing numerous felspars; magnetite occurs in irregular
1 The fossils found in the Llandeilo Beds here are remarkably well preserved,
and include, amongst others, Ogygia buchi (Brongn.), IVinucleus Jimbriattu,
Murch., Ampyx nudus (Murch.), and Siphonotreta miculci, M'Coy.
Digitized by Google
576
MR. H. WOODS OX THE IGNEOUS HOCKS
[Nov. 1894,
grains ; there is a large amount of chlorite and some leucoxene.
Minute crystals of brown mica and magnetite occur clustered
together in little groups. A section taken from the southern end
of the sill, near Park Wells, is similar to the one just described, but
the place of the augite is taken by chlorite.
The largest sill is the one to the east of the two preceding,
forming the high ground on which Welfield is situated. It is not
exposed in any quarries, but may be seen in the bed of the Wye and
at Pen-maenau Rocks. A section from the Wye, near Pen-ddol
Bocks, shows the ordinal*)' minerals.
The sill to the north-west of Llanelwcdd Church, on which Upper
Llanelwedd Wood is situated, is more irregular in form than the
others ; it is not well exposed, and in hand-specimens resembles the
rock at Pen-cerig Wood. In a section from near 4w' in Upper
Llanelwcdd the augite is rather scarce ; ilmenite, leucoxene, and
chlorite are plentiful.
We come now to the diabases on the east of the main volcanic
scries. The most important is that which forms the ridge known
as the Castle Bank.1 This stretches from Llwyn-Madoc northwards
almost to the Cannant Brook. Specimens collected from various
parts of the Bank exhibit to the naked eye a fairly uniform ap-
pearance, the differences being due mainly to the amount of
weathering ; the rock is always rather fine-grained. In a specimen
from 70 yards north-north-east of the 4 Castle ' the felspar is
abundant and very much decomposed. The augite is in rather
small quantity ; it is almost colourless and not ophitic. There is a
large amount of a green chloritic mineral, which in some cases is
derived from the augite ; in others it shows a fibrous structure, and
possibly represents a rhombic pyroxene. Secondary quartz is
abundant ; magnetite, ilmenite, and leucoxene also occur. The
silica-percontage of the rock is 54*54, and its specific gravity 2-73.
Another section taken from the south-eastern part of the Bank, just
north of the 4 Cam/ shows similar characters; but the augite is
sometimes idiomorphic.
Another mass of diabase occurs a little to tho south of Llwyn-
Madoc; it extends from the Caer to Cil-y-berllan. A specimen from
near the road south of the Caer is similar in appearance to the
Castle Bank rock. But under the microscope it differs from that in
the augite being more abundant and generally ophitic ; there is a
little secondary quartz. Another section, taken from about 150 yards
north-north-cast of Cil-y-berllan, was very similar to the last. On
the west side, south of Cwm-berwyn, the rock has rather the structure
of a dolerite than that of a diabase : it is much finer-grained, darker
in colour, and comparatively fresh ; the augitcs are mostly very
small, and never ophitic, and there are two generations of felspar,
although the earlier is not well marked ; the specific gravity of
this rock is 2*81.
1 The northern part of this ridge ia not shown in the map which acooropaiiie*
thin paper.
Digitized by Google
Vol. 50.]
OF THE NEIGHBOURHOOD OF BUILTH.
577
VII. Conclusions.
There remain now to be considered the age and order of eruption
of these igneous rocks. As already pointed out, the fossils at present
found in the andesitic ash are not sufficient to fix its age, but since
it is overlain by Llandeilo Shales containing Ogygia buchi, etc., it
may be regarded as probably of Lower Llandeilo age ; so also may
the underlying andesites. The diabase-porphyrite and the rhyolites
are somewhat later than these, but at present there is no evidence
to show whether the rhyolites are earlier or later than the diabase-
porphyrite ; from theoretical considerations one would expect them
to be earlier.
The diabases are of later date than the other igneous rocks, since
in all cases they are intruded into the Llandeilo Shales ; but nowhere
do they pierco the Silurian beds (Llandovery and Wenlock), showing
that they are of post-Llandeilo and pre-Siluriau age. This is well
supported by the section exposed in the quarry next Pen-cerig Lake,
where the diabase is seen in contact with both the Llandeilo Shales
and the Llandovery Beds : the former are metamorphosed, the latter
quite unaltered.
The order of eruption, then, in this district was probably as
follows:— (1) Andesites; (2) Andesitic Ash ; (3) Rhyolites; (4)
Diabase-Porphyrite ; (5) Diabase. The first four are of earlier date
than the Upper Llandeilo Shales, the last one later.
I must here express my thanks to my friends Mr. J. E. Purvis,
B.A., and Mr. H. Brownsword, B.A., for their kindness in deter-
mining the silica-percentages given in this paper.
Discussion.
Dr. Hicxs said that he had examined the area referred to by the
Author, and he had come to the conclusion that the contemporaneous
volcanic rocks were quite at the base of the Llandeilo Series, and
mainly associated with the Llanvim Beds — as in Pembrokeshire and
Xorth Wales.
Mr. W. W. Watts wished to ask whether there was any strong
reason for placing the andesitic and rhyolitic ashes in the Llandeilo
Series rather than linking them with the Arenigs. He pointed out
that, while the general characters of the rocks agreed closely with
those of Shropshire, the diabases in the latter county were in-
dubitably of post-Silurian age.
Digitized by Google
578 PROF. T. 0. BONNET AND MIRB C. A. BA18TN ON [Nov. 1 894,
38. On the Relations of some of the Older Fragmental Rocks in
North-western Caernarvonshire. By Prof. T. G. Bonnet,
D.Sc., LL.D., F.R.S., F.G.S.,1 and Miss Catherine A. Raisin,
B.Sc. (Read June 20th, 1894.)
Contents.
_ . ...... P»i*
I. General Considerations 578
II. Evidence from Moel Tryfaen 580
III. West of Llyn Pudarn 581
IV. East of Llyn Padarn : Inland Sections 58ft
V. East of Llyn Padarn : Alleged Unconformity on the Slate Bailwny 588
VI. Stratigraphical Succession 51KJ
VII, Comparison of Microscopic Sections 5U7
1. General Considerations.
In a recent paper published in the Quarterly Journal of the
Geological Society,3 a new and revolutionary hypothesis is put
forward as to the age and position of certain well-known con-
glomerates and associated beds in North-western Caernarvonshire.
The new explanation presents at once some difficulties, but these
have been increased in number and gravity by a fresh study of the
district. We selected those portions of it examined by Mr. Blake,
in which the more critical sections occur, and tested with the
microscope the questions raised by work in the field. The one or
the other author was already in possession of a fair number of slides
from the district in dispute, and nearly fifty additional specimens
have been expressly prepared for the present paper.
According to the new hypothesis, the strata previously mapped
and described from near Llyn Padarn and from neighbouring
districts can be distinguished into two groups separated by a
strongly marked unconformity. While the one part is held by
Mr. Blake to be of early Cambrian age, the other is 4 post-Llanberis.'
A question at once suggests itself, namely, to what epoch (from the
Menevian onwards) do these so-called 4 post-Uanberis * sediments
belong, and where in adjacent districts may we find beds that can be
correlated with them ? Of this problem Mr. Blake has not succeeded
in offering a solution, but he evidently perceives that it is one which
claims consideration.
The new hypothesis, however, would involve two consequences of
far-reaching import. The unconformity is described as being marked
by nearly horizontal beds overlying earlier strata approximately
vertical in position. Such an unconformity would be the record of
1 The larger share of the work in this paper has been done by Miss Raiein.
She has visited all the section*, often more than once. There are some which I
have not examined, and others which I have not seen since the date of my
former paper. It ie only just that I ahould make this clear.— T. G. B.
a "On the Felsitea and Conglomerates between Bethesda and LJanllyfni,
North Wales,' Quart. Journ. Geol. Soc. vol. xlix. (1&J3) pp. 441-405.
Digitized by Google
Vol. 50.] OLDEB 1RAGMEKTAL BOCKB IN N.W. CAERKARVOH8HIBE. 579
tremendous disturbances. The uplifting and denudation of the
earlier strata, previous to a renewal of deposition, are changes
which we should expect to find associated with a period of mountain-
making. This can be no local phenomenon 1 : its record must extend
over a wide area. Yet nowhere in the surrounding districts do we
find evidence of such a break throughout the whole of the Cambrian
and Ordovician periods — unless we concede that Mr. Blake has estab-
lished the existence of one, farther north, immediately before the
beginning of the Arenig epoch. Of even this hypothesis, however,
he declines to avail himself here,3 so that a second great break must
be introduced. Yet, so far as we know, there is no certain evidence
of the existence of either. Only when we arrive at the commence-
ment of the Upper Llandovery age have geologists agreed in recog-
nizing one comparable with this in importance. This difficulty is
dismissed in a few inconclusive sentences. Yet it is one which no
detailed observation, no withdrawal of any small part of the evidence
can possibly meet. It is general, and must be dealt with before the
hypothesis can have any solid foundation.
The other difticulty, which is not even considered, is partly con-
nected with the preceding one. It is the necessity of twice un-
covering the felsite 3 in order to obtain from it a great amount of
material to help so largely in forming the two series of strata, the
one before, the other after, the tremendous break we have men-
tioned.4 So complete was tho exposure of the felsite in what he
takes for the second period that Mr. Blake describes thiB 4 post-
Llanberis' conglomerate as shading into the 4 reconstructed' felsite.5
But the denudation cut even deeper, since the so-called later conglo-
merate includes granitoid and quartzite-pebbles, which must have
been obtained from early pre-Cambrian rocks. Yet, curiously enough,
the * Llanberis ' strata, though thoy have boen so completely planed
down, have not contributed any large amount of fragments. Only
exceptionally do we find these or slaty pebbles of any kind, as, for
example, at Moel Tryfaen. The detailed evidence, then, ought to be
1 Mr. Blake says it has to be decided whether ' this unconformity is any
more than a local one ' (vp. dt. p. 405). But Burely, were it local, this would
require such exceptional and extraordinary conditions as to be practically
impossible.
a Iffid. p. 465. The unconformity which has been claimed in some previous
papers, as separating the Cambrian from the pre-Cambrian, would not of course
help Mr. Blake ; and this presents no serious physical difficulties.
3 We refer to the woll-known mass which is shown in the Geological Survey
map as near Llyn Padarn, and as extending for a considerable distance from
Bethesda to the S.W.
* Although the so-called earlier ' Llanberis Beds* generally are finer-grained,
they can be clearly proved to be at places mainly composed of material derived
from the quartz-felBito. As examples we may mention beds in some of the
' banded slates' synclinal east of Llyn Padarn, and the 4 more felsitic material
. . . . almost .... pure felsitic ash,' described by Mr. Blake south of the
second conglomerate (op. cit. p. 445).
s Ibid. p. 447. Thus, apart from other objections, Mr. Blake's hypothesis of
several successive felsites (e. g. Moel Goronwy) aud their denudation will not
lessen the difficulty referred to above, since here (and at other places) the ' post-
Cambrian' conglomerate is supposed to be deposited on one of the earlier felsites.
Q. J. G. S. No. 200. 2 s
Digitized by Google
580 PROP. T. G. BONNET AS J) 11188 C. A. RAISIN ON [Nov. 1 894,
of the strongest and clearest nature, if it is to establish the supposed
unconformity. This evidence, in all places but one, is indirect ; we
will consider that instance first, and then pass on to the other
cases.
II. Evidence from Moel Trteaen.
This locality is the one which seems at first sight most to support
Mr. Blake's hypothesis. As we were unable to spare the time for
any thorough re-investigation of the adit,1 we have considered how
far the surface -exposures, taken in conjunction with Mr. Blake's
description of the tunnel,* necessitate the acceptance of his hypo-
thesis. The general succession crossed on the western slope
above and north of the Bryngwyn incline (that described as 4 the
southern slopes') is claimed as representing the tunnel-section,
but it is not very clear how the author accounts for the absence
from the tunnel of the conglomerate of the tramway-cutting.3 This
is at a lower level and strikes towards tho adit, which, it is admitted,
commences in felsite.
Tho main difficulty, however, is the apparent absence of the
summit-conglomerate from the tunnel. Certainly nothing in the
detailed section given by Mr. Blake can fully represent the extensive
outcrop on the top of the hill. Assuming the accuracy of his obser-
vations of the tunnel, there seems on our theory no other explana-
tion possible than that this conglomerate is faulted out ; and the
broad outcrop at the summit might be due partly to such dis-
turbance. This seems suggested by the changed dip found in the
associated green grits.*
The chief arguments drawn by Mr. Blake from the surface ex-
posures are, that the dip is nearly horizontal, and that the northern
slopes are covered by conglomerate and grit. Special reference is
made to two lines of crags in this direction. It is said that the
tipper " most distinctly show a low dip of not more than 5° to the
east" (op. ext. p. 462). We took the dip on several blocks and sur-
faces, of which four at least were clearly shown varying from 15° to
25° generally to S. of E. or B.E.' ; while in the grit of the summit-
1 Each of us on separate occasions has been through it, but not with good
light*.
a That difference of opinion is possible would appear from the fact that a
specimen which one of us collected at a hundred paces from the mouth or
northern end of the adit, that is, somewhere in * 29, light crystalline felsite,' is
an unquestionable felsitic grit.
3 Prof. Bonney in 1878 collected a specimen from the spoil-bank at the N.W.
mouth of the adit which cloeely resembles this conglomerate, and noted
• Cambrian conglomerate' as one of the four varieties of rock lying about In
1880 he parsed through the adit (but only with a bull's-eye lantern) and found
« Cambrian conglomerate' following after the felsite with (?) some felsitic
grit. This is probably identical with the rock mentioned by Mr. Blake in a
note (op. cit. p. 460).
* These do occur, although Mr. Blake says (op. cit. p. 462) :— • nor can we find
any green grit on the summit.'
" These, in some cases, are the dips shown on exposed surfaces, and so may
be less than the true angle.
Digitized by Go
Vol. 50.] OLDER FRAGMENTAL EOCB8 IN N.W. CAERWABV0K8HIRE. 581
crags the dip is distinctly as much as 40° to a westerly or south-
westerly point (approximately WJ3.W.).
It is then said that " the lower crags are of conglomerate like that
of the summit." The rock clearly is a conglomerate, one of those
largely made up of material from the quartz-felsite, with pebbles
also of quartzite and occasionall}' of granitoid rock, while the large
slate-fragments of the mass at the top of the hill are wanting. Thus
it seems to us that lithologically this conglomerate does not resemble
that of the summit ; it more probably represents a band at a different
level, like that of the tramway-cutting. The argument implied
in the words " all is covered by conglomerate and grit " is less
strong than it seems, because no small part consists of unbroken
sword. So far as any inference is justifiable from the latter fact ,
it would be that there probably is a softer rock, such as slate, in
this part of the hill.
Thus it does not appear that we can prove the conglomerates on
the hill to form a single great mass, or that this is approximately
horizontal as implied by Mr. Blake 1 : hence wo are still not satisfied
" that the conglomerate lies unconformably on, and is independent
of, the underlying members of the Cambrian Series" (op. cit. p. 463).
III. West op Lltn Padabn.
In the district west of Llyn Padarn we will discuss first that
part of the railway-section where the evidence can be best brought
to a test examination. This is towards the inlet of the lake at
the north of the cutting. It is stated as an argument here that
* Purple Slate' (op. cit. fig. 6, 6; fig. 7, no. 11) occurs in contact
with the felsite with no conglomerate between.3 The section of
the supposed junction is undoubtedly very difficult. "Wo agree with
Mr. Blake that both the slate and the felsite-like rock are broken,
but after careful microscopic study of both varieties we have come
in other rospects to rather different conclusions. The purple rock
certainly appears to bo a variety of slate. The light- coloured one
in junction-specimens is almost wholly composed of felsitic material,
and might be a crushed condition of the quartz-felsite, but the
relation of the two is moro like that of sediments, and the darker
sometimes contains bands of an intermediate character. Thus the
mass is most probably an interbanded dark mud and felsitic grit ,
1 There seems in addition one negative argument which should be considered.
If the thick massive conglomerate unconformably overlies Cambrian strata,
nearly horizontally or with a low dip to the east, then it would be a curious
coincidence that it should have been cleanly removed from over all the purple
slates. So far as we know, no representative of it has ever been noticed,
although extensive quarries are worked almost continuously along the east of
the hill. The conglomerate-and-grit has so successfully resisted denudation at
one part that it forms the thick crags of the summit, while less than 100 yards
away the same resistant strata have been entirely removed.
We have to thank the owner, Mr. Menzies, for kindly giving us some inter-
esting details relating to the slates worked in the quarries and to the associated
grita.
8 Ibid. p. 451.
2s 2
Digitized by Google
f)b2 FBAGMENTAL BOCKS IN N.W#CAERMARV0N8HIRE. [Nov. 1894.
subsequently very much compressed and wrinkled.1 The latter factr
which seems quite clear in the three slices examined, appears con-
trary to Mr. Blake's view of the rocks.
The * Purple Slate ' is said by Mr. Blake to occur in mass along
the lower levels only (ibid. p. 450).3 The rock is partly purple and
is slaty, but wo fail to see any evidence which would correlate it
with the purple slate of the quarries, as seems intended by Mr.
Blake in his use of the term. Lithologically even, one of the most
characteristic structures in the 4 post-Llanberis ' strata — the inter-
banding of fine grit and purple slate — is certainly indicated in one
part of the mass. It is followed in the railway-cutting by the beds
of the synclinal, which are taken as * post-Llanberis' (see our fig. 1,
7 bt 7 c, 7 d, 7 e, and 6, 7, 6, in map, fig. 4, p. 594), and the dip of
the ' Purple Slate ' (fig. 1, 7 a) is similar in direction to that in the
northern arm of the synclinal (about 70° S.K. by E.). The southern
arm, however, gives still more distinct evidence. Mr. Blake describes
and draws the conglomerate, g, as mounting " over the back of a
dyke of greenstone " (op. cit. p. 450, fig. 6). We find below this
conglomerate a purple slaty rock or banded and cleaved argillite,
indistinguishable in hand-specimens from that claimed as * Cambrian '
on the north (see our fig. 1, 7 b, la). Bands similar in character
also occur in the * post-Llanberis ' synclinal. Thus the supposed
1 Cambrian ' beds dip (at the north) with the 4 unconformable ' strata
above, can be matched with bands intercalated among them, and
appear to be reproduced to the south, turning up in that arm of the
synclinal, exactly as we should expect if there were no unconformity.
The other argument used here is the distribution of the con-
glomerate. It is said to occur at the spots marked a, c, g, m (op. cit.
p. 451, fig. (i), extending over different beds of the earlier series.
The southorn mass m cannot give much help. Mr. Blake, we suppose,
faults it down, — we think it more probable that the rock is faulted
up. The conglomerate a, however, is supposed to pass over to that
marked c in the synclinal (see 3 and 7 6 in our fig. 1, and 3 and 6 in
map* p. 594). Of these Mr. Blake says " there can hardly be a doubt
.... that [they] are parts of the same mass" (loc. cit.). But litholo-
gically they appear somewhat distinct, both in hand-specimens and
on microscopic examination. The conglomerate c has a less squeezed
look than the conglomerate a, is more purple, and contains clearly
fragments of rocks of more basic or intermediate composition, which
seem practically absent from the latter. Further, the thickness of c
is probably less than 20 feet, while that of a must be much greater.
Wo believe that it is a distinct layer at a higher horizon, and it is
i Undoubtedly a mate of felsite occurs just beyond ; but, as the slate is con-
spicuously wrinkled, its dip con hardly be parallel to the surface of the igneous
rook-
u Again on p. 455, it is stated that ' nowhere are the felsite and Purple
SUte, which are seen at the level of the railway (11, 12), to be found above.*
The * Purple slate is discussed in the next few sentences. But a felsite also
occurs up the hill S. W. of Tan-y-pant Cottages. It is difficult on any theory
to explain this outcrop, but it undoubtedly is >hown in several well-marked
Digitized by Go
584 l'EOF. T. O. BON.NET AND MISS C. A. KAISIN ON [Nov. 1 894,
followed by two or three still thinner, — a sequence which commonly
happens.
Thus we maintain the 4 opposite conclusion/ to quote Mr. Blake's
own words,1 and although we deny the identity of b with the Purple
Slate, we do not ' miss the synclinal,' but make it more definite ;
and we fail to see any reason why m at least should not be faulted up.
Tracing the beds inland, the last-mentioned faults would account
for the difference of the rocks exposed in the grounds opposite
Glyn Padarn. Our observations there do not accord with Mr. Blake's.
We are told that we come to grits and conglomerates which are
* corresponding rocks ,a to those of the railway-section. The con-
glomerate to is the massive quartz-felsite conglomerate with
quartzite-pobbles (3 in fig. 4, map, p. 594) ; but the conglomerates
or pebbly bands (in the grounds) and the associated grits are, many
of them, quartzose rocks containing quartz-pebbles and grains of
blue quartz (11 in fig. 4, map, p. 594). This rock is similar, there-
fore, in many respects to the green grit with blue quartz associated
with the Purple Slates 8 ; and in these very masses layers of purple
slate or argillito occur. Even the "large mass of purple slate
lying horizontally on the top of finer conglomerate " 4 seemed to us,
if we correctly identify the place, to belong certainly to one of
these bands. It is not, therefore, a fragment derived from any
possible underling rocks, and so no proof that the series is 4 post-
Llanberis ' in age.
Mr. Blake says : " If we pass along an E.N.E. to W.S.W. line
. . . we cross a definite succession." It is not easy to recognize this
definite succession. Compact grits are followed by a coarse green
pebbly grit with bands of conglomerate and of argUlite, but beyond
the wall this runs on the west right up to the slate tips ; the grey
slate outcrop being nearer the quarry. It is further stated that
this succession has " a gentle dip towards the E.X.E." and that
" we have here a series .... nearly horizontal." Some of the
dips which we noticed are obscure, but three are clear : — to N.N.W.,
to N.W., and to N. of W. at 30°, 18°, and 30°; while one dip to
S.E. at 32° appears to be due to a synclinal roll.
The description of a regular series takes no account of any
faults, but one at least (probably two) can be traced across the
neighbouring slate-quarry.* The apparent interruption of this slate
may be due to another line of fault roughly north-easterly, for, as
we have stated, a fault is seen (or rather parallel faults) on the
railway-section near the continuation of the line of junction.*
1 Op. tit. p. 452. * Ibid. p. 463.
' A green grit, containing similarly blue, purple, and red quartx-graina, is
characteristic of certain bands in the Harlech and Barmouth areas.
* Ibid. p. 453.
5 This may be partly the cause of some variation in the dips and outcrops
nearer the road.
• These are shown in the section giren by Mr. Mavr (Geol. Mag. 1868, pi. vi.
and p. 121 ), from which our drawing differs in some minor details. We have
not, however, thought it necessary to give a separate diagram, as wo believe
that Mr. Maw's drawing correctly represents the important points of the
general succession, except in the matter of the unconformity.
Digitized by Go
Vol.50.] OLDBB FBAGJLENTAL R0CK8 IN N.W. CA.ERXAKVON8HIBB. 585
Mr. Blake speaks of it there as a * slight fault/ hut it is so only
on his own hypothesis ; to argue from that statement is reasoning
in a circle. This ' slight fault ' is supposed to account for the
grit and conglomerate being carried down to tho railway-level ;
while at the higher ground they are «* all but actually seen to overlie
[the Purple Slates] unconformably " (op. cit. p. 454).
We have discussed the grounds for this view, drawn from the
lithological succession and tho dip. Tho remaining argument, as
given by Mr. Blake, is : ** if I understand rightly the section given
by Mr. Maw .... it runs beneath these very grits and con-
glomerates." But, apart from the fact that that section repre-
sents conglomerate under purple slate, there is a serious misunder-
standing, for the adit described begins about 80 yards away from
these grits, since it extends from the second to the third Glyn-
rhonwy Quarry.1
Passing to the north-west, we cannot agree that the conglomerate
can be traced 4 step by step from 13 by 14, etc., to 19 ' (op. cit. p. 455).
It can be traced from 13 nearly to the streamlet which comes
down (past Tan-y-pant) to the corner of the inlet of the lake, but —
as we believe— not beyond (3 in our map, p. 504). The conglo-
merates south of the streamlet appear to represent the — probably
thinner and higher — bands of the railway-section (f5, etc., in map,
p. 594). Along the boundary next the felsite, we are told that the
conglomerate behaves as an unconformable deposit. The variation
may be due partly to faulting, partly to the occurrence of inter-
changeable deposits of grit and coarser material, much as the local
sandy and pebbly beaches of the present day. But the important
outcrop is the ' knob of hard Purple Slate ' intervening between
felsite and conglomerate. The few such knobs as we saw appear
to be part of the purple banded series occurring on the hill,a and
do not separate the felsite from the conglomerate. At the place
(21) 3 marked by Mr. Blake as proving the existence of 4 Cam-
brian ' slate, we "find the outcrops 4 next the felsite to be, firstly a
cleaved, rather coarse grit somewhat resembling a * rain-spot'
breccia, then a purple quartz-felsitc grit with pebbles, a purple
banded grit and argillite, greenstone, then purple grit, after which
the quartz-felsite conglomerate reappears (see map, p. 594).
Then we turn to the 4 associated rocks ' and the evidence of
their lamination. Mr. Blake says that 44 almost wherever seen these
lamina?, etc., are horizontal .... a circumstance which first excited my
1 We hare to thank W. Roberta, Eaq., the manager of the Glynrhonwy Slate
Quarries, for very kindly giving us this and some other information in answer
to our enquiries. He mentioned also, what seemed to ua a point of some interests
that the goodness of the slate appeared to depend on the occurrence of an
adjoining mass of grit ('granite' of the quarrymen).
a Included in Mr. Blake's map in the symbol ' Post-Llanberis conglomerates
and grit,' flg. 7 ; also fig. 2. This inclusion of things so different as coarse
conglomerate and banded slaty and gritty rocks under one symbol makes
Mr. BlAke's maps difficult to follow, and likely to mislead an observer unfamiliar
with the ground.
' Op. cit. p. 462, fig. 7.
* At the parts measured by scale on the map.
Digitized by Google I
580 PROF. T. G. BOKNEY AND MISS C. A. RAISIN ON [NoV. l804i
suspicions that thev were not what they had been taken for.
In an area extending for abont } mile "above the road from the
Glyn Peris Hotel to the commencement of the felsite," passing
Tan-y-pant, some roughly horizontal outcrops occur,2 but fourteen
dips more or less trustworthy were measured, out of which not
one was horizontal, very few were gentle dips, the average was
from 30° to 35° or 40°, and two at least indicated high angles of
50° and 70°.s
We have not worked over all the details farther up the hill, but
until some distinction is drawn between different grits and con-
glomerates no inference from isolated outcrops can be trusted.
Certainly the specimens at one part from near Cefn Du quarries,
lithologically, arc similar to the quartz-grits which are found among
the workable slates, and are very different from the great quartz-
fclsite conglomerate. If slate-holes were found on different sides of
this grit,4 this would be no more than might have been anticipated.
IV. East of Lltn Padabn : Inland Sections.
Along the eastern boundary of the series of conglomerates, etc.,
Mr. Blake's map is misleading, even according to his own descrip-
tion. As he says, the conglomerate i resembles a, yet he marks it
by a different symbol (op. dt. p. 447, fig. 2). It is with this con-
glomerate, t (3, near the Boat-house, in our map, p. 594), that we
have to correlate various outcrops north of Mr. Blake's 18, west 0f th®
felsite on w hich 24 is marked, while the so-called ' Banded Siat©s
(g-h, op. ext. fig. 2, * Cambrian ') are many of them lithologidUy
indistinguishable from — and can be traced along to — the banded
gritty series of the east of Y Bigl marked as ' post-Llanberis ' (see
our map, 5, 6, 7, p. 594).
A further argument is based on the stratigraphy of Moel Goronwy
{Moel Gronw). Mr. Blake states that the felsite of this hill differs
from that of Clegyr in being more compact.5 We think it would be
an improvement to substitute * less ' for 1 more,' but the difference
is trifling and the former rock agrees in its general character0 with
the ordinary felstones of the neighbourhood, displaying a fluxional
1 Op. supra ext. p. 455. It is impossible, we find, to be sure of the exact
outcrops indicated by the numbers on Mr. Blake's mape ; but the area examined
here extended beyond * 18, in, 10.' the points to which he especially referred.
' At some spot* small synclinals or anticlinals seem indicated.
3 Other dips not so well exposed were measured, and many more were
noticed. Some variation in the dips doubtless is due to the intrusive greenstone.
The whole hill Tery potwibly is underlain by a large mass, which may occur
like a laccolite, and certain of the strata are baked and changed to porcellanite.
Some knobs of hard purple slate occur, which evidently are parts of the banded
series altered in this way. The general dip in the part towards the felsite is
to a north-westerly point, but south of the Tan-y-pant streamlet the direction
is changed.
4 Op. cit. p. 455. 5 Ibid. p. 450.
6 One slide of the rock includes many small crystals of secondary minerals,
some being white mica, others probably a carbonate. But similar mineral*
ocour in the main mass of the felsite,
Digitized by Go
Vol. 50.] OLDER FRAGMBNTAL ROCKS IS N.W. CAERNARVONSHIRE. 587
structure equal to that of Cwm-y-glo, and enclosing lumps of a cora-
pacter and redder felstone,1 as the principal mass does near Bettws
Gannon. Although the massive conglomerate of the western is
wanting on the eastern margin of the igneous rock of Moel Goronwy,
yet the felsitic grits with occasional seams of quartz-felsite pebbles *
indicate a similarity of material (4 in our map, p. 594). But the
existence here of a fault seems highly probable from the nearness of
the outcrop of purple slates, from the absence of the main mass of
the conglomerate, and from the variation found along a continuous
lino down to the lake. On the railway Mr. Blake Btates that there
is possibly a fault, but makes no allowance for its continuance at
Moel Goronwy.
Tracing next the outcrops along the western boundary of the
conglomerates, etc., the most important argument is the sudden
change at the north of the quartzite-conglomorate (11, 12), which,
if the map given by Mr. Blake were accurate, could be explained only
by more than one fault. But instead of the rocks cast of the line
25 to 11 in his map being rightly represented by the same symbol
as the great quartzite-conglomerate, they require a different sign,
and the difference between the rocks east and north of 11 — that is,
between ' post-Llanberis ' and * Cambrian ' — does not exist. The
same purple and grey-weathered, finely laminated and banded grit
and argillite (which we should describe as of Y Bigl type) occurs,
followed to the eastward in each case by green banded slaty rocks
and grits, like those on the summit of Y Bigl. If the fault which
Mr. Blake marks on the railway (op. cit. p. 445, fig. 1 , between a and
•r) is continued inland,3 it would account first for the conglomerate,
then for the felsite, coming into close association with the banded
gritty or slaty rocks (see Fa in our map, p. 594, south of Tyddyn Du,
3, 1, and 7).
Between the two boundary-lines the rocks of the slate-railway
section strike towards the slopes of Y Bigl. On this hill several
examples are noticed, and two are drawn representing grits overlying
Pale Slates (op. cit. pp. 448, 449, figs. 3, 4). We were not satisfied as
to this interpretation for the one which we visited, but as the horizon
of these beds is part of the point in dispute, the sections would only
supply an argument for an unconformity to an observer who already
is convinced. Wo are also told of the difference between all these
rocks of Y Bigl and those of the railway syncline. As we shall
show, the latter include some banded grits and conglomerate, such
as occur over the higher slopes. It is, however, true that here on
the hill the pale banded slates of the railway do not seem to extend
over a wider area, as should happen in a soctiou of a syncline,
1 8ir A. Geikie has called attention to both these characteristic*, Quart.
Journ. Geol. Soc vol. xlvii. (1891), Pres. Addr. Proc. p. 94.
3 These apparently are the ' curious breccias derived from the felsite.' to
accouut for which, on his hypothesis, Mr. Blake has to suppose the Moel
Goronwy felsite a later eruption, op. passim cit. p. 450.
3 The fault which has been suggested by one of us as occurring between the
felsite and the conglomerate was not supposed to be great, and might have died
out in a short distance from the lake.
Digitized by Google
588 PROP. T. O. BONNET AND MISS C. A. RAISIN ON [Nov. 1 894,
made by gradually rising ground. But if the axis of this syncline
sloped to the south-west at an angle of about 12°,' the lower strata
of grit, etc., would spread over a broader tract. Is, however, the pale
slate completely absent from the summit of the hill ? It seems to
us that it does occur (probably over a limited area), and that
although the rocks show varietal differences, there is no strongly
marked lithological distinction.2
Mr. Blake's hypothesis moreover only seems to substitute another
and rather greater difficulty. If the Moel Goronwy felsite overlies
in succession the Banded Slates, what has become of the syncline
which admittedly has extended from the railway for nearly \ mile
to Y Bigl, and then has died out in less than MOO yards ? Or, if the
syncline is continued, then the Moel Goronwy felsite must be
separated from the Banded Slates by a fault. Then what has
become of this fault at the railway ? (Compare fig. 5, p. 597, postta.)
The strata of Y Bigl also are said to be horizontal, and this, if
true, would be strongly against the view that tbey belong to the
railway succession.3 The same position is exhibited in Mr. Blake's
fig. 5 (op. cit. p. 449 )/ As no dips are given on the map (away from
the lake), we were unable to verify the particular observations on
which the statement was founded, but the amount of the dip was
measured at some twenty places 4 lying within Mr. Blake's ' posfc-
Llanberis ' area on Y Bigl. Of these observations, in one the
crumpled laminae maintain a roughly horizontal direction,6 in all
others the dips were not less than 35°, and in more than half they
were as much as 50° or higher.7 And these are the beds whose
horizontal position proves the unconformity !
V. East op Llyn Tadarn : Alleged Unconpormitt on tdk
Slate Railway.
In the previous instances the evidence is indirect, but at one
spot wo are told that the hypothesis can be brought to a direct test.
1 A greater slop© than this is indicated at Yr Allt Wen in the Survey
Memoir, fig. 04, p. 181.
3 Specimens have been examined under tho microscope and tbey show a
certain amount of family likeness, particularly in the courser bands. In each,
but especially in two specimens from the syncline of the railway, several rather
angular fragments of the dark rock (described infra, p. 5U6) occur, which
generally are abundant in Mr. Blake's ' post-Llanberis ' group.
3 An argument in support of this view may be drawn from the strike which
can be traced in certain distinguishable layers as roughly to north-eastward ;
that is, agreeing in direction with the outcrops indicated in the railway section.
4 This section is difficult to understand, unless we are to suppose that a fault,
throwing down the 'post-Llanberis' conglomerate at the N.W. end, ran oppor-
tunely along the nearly vertical junction of tho felsite and the banded slates.
But even so, the latter must have rested on the former and have been afterwards
curiously twisted up just on the southern side of the fault.
5 These were the clearest exposures. The dips were noticed at many other
outcrops.
0 At a place which we believe may be on tho line of tho anticlinal from the
lake.
7 Here also, as at Moel Tryfaen, these measurements are sometimes les* than
the true dipB. See p. 580.
Digitized by Google
VoL 50.] OLDER FKA OMENTAL ROCKS IN N.W. CAERNARVONSHIRE. 589
To this must be the final appeal. Mr. Blake maintains that by the
side of tho slate-railway east of Llyn Padarn, his ' post-Llanberia '
conglomerate can be seen unconformably overlying the beds which
are admittedly Cambrian. This is at the spot originally described
by one of us 1 as the second of the three masses of conglomerate
(numbered 3, 6, and 3, in our fig. 2, p. 590, and in our map, p. 594).
It is a thinner mass, as was then noticed, and it also differs some-
what lithologically from the first and the third, so that, from these
reasons, and from careful tracing of the dip in the associated beds,
we now incline to think this second conglomerate may be a different
and slightly higher band.
In the original diagrammatic section along the railway given in
the description referred to above, the synclinal and the anticlinal
were shown. At the latter part Mr. Blake introduces a fault, and
wo (though partly for different reasons) think that one probably is
present ; but we do not agree with him in thinking that " there is
no anticlinal " (op. cit p. 446). We still adhere to the original
diagram, but should shift the position of the anticlinal axis in it-
southward, so as to fall nearly on tho third conglomerate a (3 in
fig. 2, p. 590 ; and 3, near Boat-house in map, p. 594). Again and
again, in the little crags just above the railway, the dips are well
exposed — towards a north-westerly point on the one side, towards
a south-easterly point on the other side of a line which is thus
clearly anticlinal.
We aro told, however, that the unconformity is distinctly proved
at one place, and it is drawn as shown in Mr. Blake's fig. 1 (op. cit.
p. 445). A conglomerate A lies unconformably upon the slate-
breccia <7, and Mr. Blake states that Prof. Green, Sir A. Geikie,*
and himself have recognized the difference, "which others have
failed to do.'* Even the latter statement is incorrect, for one of
us called special attention in 1879 to tho fact that tho seotion
shows conglomerate and a sort of ' rain-spot ' rock underlying the
conglomerate.4 In the conglomerate, as shown in the cliff-section,
the pebbles are rounded or subrotund, larger, and fairly close, but
with a finer gritty matrix between.11 Tho upper part is weathered,
and this causes the pebbles therein to stand out in relief, but they
are present equally in the lower unweathered part, the two clearly
forming a single mass. The underlying * rain-spot ' rock is more
strongly cleaved, as stated by Sir A. Geikie. This character, however,
1 T. G. Bonney, * On the Quartz-felsite and Associated Bocks at the Base of
the Cambrian Series in North-western Caernarvonshire,' Quart. Journ. Geol.
Soc. vol. xxxv. (1879) p. 309.
1 The greater thickness of the third conglomerate might be due, partly at
least, to the anticlinal roll. Some, however, of the first conglomerate might
be cut out by the fault which limits it on tho south.
3 Sir A. Geikie, however, does not admit the existence of the unconformity.
Quart Journ. Geol. Soc. vol xlvii. (1891) Pres. Addr. Proc. p. 05, noto.
* 4 A sort of • rain-spot' rock at the base of the middle mass, T. G. Bonney.
op. svpra cit. p. 315.
3 The pebbles are not unusually 1£" or 2" long by 1^" broad, but most
oommonly from to f ". In the ' rain-spot ' rock the fragment* are
smaller and more elongated along the cleavage.
Digitized by Google
Digitized by Google
Vol. 50.]
FKAOMENTAL KOCKS IN N.W. CAEKNAUVOXSlIIKK.
591
is still more clearly marked in the banded grit and argillite, which
occur above the rounded conglomerate. That the upper con-
glomeratic part was deposited continuously on the lower breccia is
proved by the finer matrix graduating from the one to the other.
This is seen unmistakably both in the cliff and in a mioroscope
section cut from a junction-specimen.1
Not only, however, is the unconformity quite disproved, but the
only line which might be supposed, and has been supposed (by
Prof. Green), to mark it is not shown by Mr. Blake. His drawing
improves on the earlier sketch by altering the actual line to a non-
existent division. The conglomerate is not mast-headed on the top
of the lower part of the cliff as shown by him. The lino of
separation is not a ' nearly horizontal lino.' It more closely
approaches that position just at its southern end, but soon curves
and slants down to the railway, as is shown roughly in Prof. Green's
drawing, and with a little more detail2 in the sketch on the
following page (fig. 3). 3
We are told, however, not only that there is a 4 nearly horizontal
line of separation/ but also that in the underlying rock 4 different
vertical sheets ' have different characters.'1 The * nearly horizontal
line,' as already stated, does not exist, neither do the 4 vertical sheets.'
Mr. Blake says that the conglomerate (which we prefer to call, for the
sake of distinction, the 4 rain-spot ' breccia) is ' vertically bedded.'
It has, indeed, a roughly vertical cleavage, but of stratification in
this direction we could see no evidence. It is stated that it changes
44 in a horizontal direction to more and more felsitic material till it
is almost a felsite or puro felsitic ash." LithologicaUy we should
not object to this description, but the first distinct change, passing
from the 4 rain-spot ' breccia to the southward, seems marked by a
line dipping north-westerly at a moderate angle (about W.N.W.
35' ), which hardly can be considered to mark a 4 vertical sheet.'
Also, in the underlying felsitic rock (which possibly may bo a squeezed
grit5), a band seems indicated (although indistinctly) showing a
similar dip. Thus the dips in the section roughly agree : namely,
1 In this slide an infiltrated mineral seems to us to be a kind of opaline
silica. Other slides prepared from Mr. Blake's ' post-Llanberis uncouforni*
able conglomerate ' A show that the materials are of the same character as
those in the underlying breccia, and different from the conglomerates a and i
with which he classes it.
2 From drawings made on three separate occasions by two different
observers.
3 It seems, then, since Mr. Blake himself has not succeeded in correctly
representing the cliff, that my words—' the section is not so clear in nature as
in the diagram ' — were not unjustifiable after all. — T. G. B.
4 It must be remembered that the bands originally supposed to denote vertical
layers of slate proved on examination to be thin dykes of compact diabase,
C. A. Raisin, Quart. Journ. Geol. Soc. vol. ilvii. (1891) p. 333.
5 This rock is so much affected by pressure and micro-mineralogical changes
that it is very difficult to determine whether it has been originally a felsite or a
felsitic grit. In an earlier description by one of us it was regarded as possibly
the former faulted up, but we now incline, though with hesitation, to the latter
view. [Also, even if a faulted junction occurs, I doubt whether the line of it is
visible, as was formerly suggested.— 0. A. B.]
Digitized by Google
Digitized by Google
Vol. 50.J FRAGM UNTAX ROCKS IN K.W. CAERNARVONSHIRE. 593
that in the so-called line of unconformity, that above it, and that in
the possible banding below it.
The alleged unconformity, therefore, seems not only unsupported,
but also actually contradicted by direct evidence. If further proof
were needed, it would be found in the continuation of the section
northward and southward. The dips in both directions and the
lithological characters give some evidence. On the north Mr. Blake
marks * greenstone or green grit not properly examined ' (op. cit.
p. 445). We find here a greenstone which is partly compact,
partly porphyritic, and grits (2 & 7 in our fig. 2 ; see also map,
p. 594). The grits are distinctly banded, and continue the succession
above the conglomerate, with purple argillito-laminaD of the typical
intcrbanded character. In addition, some bands show distinctly the
4 rain-spot ' breccia-type, proving the recurrence of this same variety
above the supposed unconformity.1
Wo have discussed this section at some length, because it is the
place of which Mr. Blake states that he 4 cannot imagine a more
satisfactory proof of unconformity in a single section' (o/>. cit.
p. 446). If unconformity there be, we have never before seen one
so successful in concealing itself.
VI. Stratigrapmcal Succession.
Here, perhaps, a short summary may be given of the explanation
which we venture to suggest for some of the sections described
above.
On the west of the lake the conglomerate next the felsite (and
largely derived from it) extends above the road above Tan-y-pant,
followed by a grit of similar material. Still higher up on the hill,
interbanded grit and argillite occur, with pebbly layers and a kind
of * rain-spot ' breccia. The oblique direction of the outcrop of
these beds, and their general dip to a north-westerly pojnt, i. e.
towards the felsite, indicate the probability of a line of fault along
the boundary of the igneous rock (F4 in map, p. 594), as was
formerly suggested by one of us.a
The conglomerate, however, and other beds are abruptly termi-
nated near the little streamlet already mentioned, beyond which
a sudden change of dip is found, so that this also seems to be a
parallel line of fault (F4 in map).' By it the reappearance of the
felsite towards the lake may be explained, as well as the crushed
and schistose condition of some of the rock in the small 4 stream
quarry.' But this fault makes it more difficult to come to a
1 Bands more or less similar occur at other places — in the syncline by this
railway, on the railway west of Llyn Padarn, and on the hill above Tan-y-pant.
a T. G. Bonney, Quart. Journ. Geol. Soc. vol. xxxv. (1879) p. 314. This fault
might account for the true felsitic conglomerate reappearing in email exposures
near Groeslon, and for the crushed condition of other beds near.
3 A fault roughly near this seems to be marked on the Geological Surrey
map. Possibly another parallel fault occurs, bringing up the felsite N.W. of
this, already mentioned. See note, p. 582.
Digitized by Google
Google
Vol. 50.]
yilAGMENTAL KOCKS IN N.W. CARNARVONSHIRE.
595
conclusion as to the exact position of the purple felsite which has
been described by Sir A. Geikie.1 If wo may infer from its high
southerly dip that it is an interstratifiod band on the S.E. side of
the fault, then, as Sir A. Geikie believes, it probably would be a small
lava-flow higher in the succession than the great quartz-felsite, from
which it differs lithologically. If, however, it be on the northern
side of the fault, this difference would lead us to suppose it to be an
external part of the lava-flow. At parts it has remained uncleaved,
and this is especially the case in an outcrop well shown (in a dry
season) at the edge of the lake. We have already dealt (p. 585)
with the alleged junction of felsite and ' Cambrian slate ' in the
crag nearly between these two localities.
Neither of the faults before mentioned is great, not so large as
many of the parallel displacements among higher strata which are
shown in the Geological Survey memoir and map.3 Beyond the
stream fault, the interbandod argillite and grit probably belong to
the syncline which is well marked, along and above the railway, by
bands of purplish conglomerate. The next cutting through bastard
slates and greenish grits, which, owing to undulations, extend for
some distance, though they have proportionally a rather small
thickness, exhibits not a few faults, so that probably the general
result has been to let down the whole mass in a kind of trough.
Unless this be so, these beds can hardly be equivalent to the green
banded halleflinta and grit on the east of Llyn Padarn. The rock
adjacent to the conglomerate (south of the bridge in Glyn Padarn
grounds) is slickensided and the junction probably is a faulted one.
This conglomerate, as we have said, may be the representative of
[Note to Map. — A few outcrops in this area have not been visited,
and othors need re-examination to test the hypothesis here repre-
sented.3 Further, many variations occur (not possible to show on
this map), apparently due partly to small faults or rolls, partly to the
slope of the synclinal or anticlinal axis. This axis seems to dip with
the slope of the hill, sometimes at a less angle. Also the different
layers mentioned above are not always sharply distinct, gradations
occurring between them, which would be expected, if (as the
Authors believe) the rocks form a continuous series. The Authors
are fully aware of the defects of the map, but they nevertheless
insert it, since, notwithstanding its imperfections, it may be of
use to make parts of the accompanying paper more easily under-
stood.]
1 Quart Journ. Oeol. Soc toI. xbrii. (1891) Proa. Addr. Proc. pp. 96, 97.
3 The stream fault, apparently the greater, might have a throw of 140 feet ;
but such an estimate is purely hypothetical.
* Thus beyond the road south-west of the Moel Goronwy felsite (although
part is gntcsed over) conglomerates are exposed, and possibly they include some
representative of conglomerate 3, in which case its outcrop might oztend con-
tinuously to the west of Moel Goronwy.
At * the ground is largely covered with slate tips, and is partly grass, with
some outcrops of grits, etc.
Q. J. G. S. No. 200. 2 t
Digitized by Google
596 PKOF. T. G. BOMNBT AJfD MISS C. A. KAISIV OK [Nov. 1 894,
that next to the felsite, which lithologically it seems to resemble.
In that case the fault probably would be as great as that north of
the section east of the lake, while the throw of one to bring in the
Purple Slate would have to be rather greater.1
North-east of the lake the following seems to be the general
succession of the beds : — (a) a lower conglomerate mainly derived
from the quartz-felsite, often containing also some pebbles of quartzite
and granitoid rock (3 in fig. 2, p. 590); (6) a grit of similar
materials (4 in fig. 2) ; (c) coarse strata, including fairly numerous
fragments of somewhat basic igneous rock,2 as in the ' rain-spot '
breccia, the overlying conglomerate, and other pebbly bands (5 and
6 in fig. 2) ; associated grit of similar composition interbanded with
argillite (7 in fig. 2) ; (d) green banded finer grit, hallefiinta, and
argillite and purplish fine-grained rocks (8 in fig. 2), leading up to
the Purple Slate. Those last indicate the beginning of the con-
tinuous quiet deposition which characterizes so much of the
Cambrian period. They appear to be associated with the green
grits containing coloured quartz-grains, as already described.
In lithological character the third (or southern) mass of con-
glomerate in the railway-section seems to be similar to the first or
northern. As already described, the dips above the third con-
glomerate indicate an anticlinal, and thus the grits, conglomerate,
and banded series on the north may be taken as higher beds. If so,
they are probably cut out to the north-west of the synclinal of green
banded rocks, and to the south of the third conglomerate, by two
faults, both of which are admitted by Mr. Blake (see Fa and F3
in our map, p. 594). Probably the fault between the felsite and
the conglomerate (Fl) is small, but that along which the greenstone
is intruded on the south of the western conglomerate (Fa) is greater,
for it apparently cuts out beds 4, 5, 6 (figs. 2 and 4), perhaps a little
of the upper part of 3, and some of the lower part of 7.
We believe that the anticline of the railway-section is indicated
to the N.E. at various spots 3 towards the Moel Goronwy felsite, and
1 Possibly the first might be 400 feet, the second (still more difficult to esti-
mate) 000-700 feet But the fault at Nantlle is described by the Geological
Survey as throwing the slate directly against the quartz-felsite.
3 Probably similar to those mentioned by Sir A. Qeikie (Quart. Journ. GeoL
Soc. vol. xlvii. 1891, Pres. Addr. Proc. p. 96). We do not, however, see that
there is proof of the contemporaneous ejection of these. It is difficult to con-
ceive them as the ejectamenta of expiring volcanic eruptions, since they are
different from any of the larger masses of igneous rock in the neighbourhood —
unless, indeed, certain more distant rocks of similar composition (such as those
in the Lleyn) could be proved to belong to this age.
9 At more than one place a close resemblance can be traced to the banded
grit south of the third conglomerate on the railway, dipping south-easterly, and
other dips to the north-westerly point sre exposed. Between the two roads
which join to the east ward at the School, a curious purplish rock occurs, and
also a more normal-looking purple felsite (po«sibly a dyke — we have not
examined its relations). The former shows in places a clean- welded junction
with a greyish felsite and exhibits a structure like a flow ; it even runs in
among fragments of the felstone. Both rocks have been affected by subsequent
pressure. The purplinh rock rather reminds us of a specimen described by one
of us from Baron Hill Park, near Beaumaris (T. G. Bonney, Quart. Journ.
Geol. 80c, vol. xxxix 1883, p. 472).
Digitized by Google
Vol. 50.] OLDER FRAG1TB5TAL BOOKS IN N.W. CAERNARVONSHIRE. 697
in the dip of some of the beds to the west of that hill. We notice
that even the map given by Mr. Blake (op. cit. p. 447, fig. 2) would
be more easily interpreted on our hypothesis (fig. 5 below).1
In attempts to connect the readings on the two sides of the lake,
we find there is a general correspondence. A double fault seems
indicated near the felsite on both railways, the throw being greater
on the north-east of the lake. It appears possiblo that the small
Fig. 5. — Section across Mod Goronwy, illustrating the probable
relations of the beds mapped in Quart. Journ. Oeol. Soc.
vol. xlix. (1893) p. 447, fig. 2.
1. Quartz-felsite.
3. Conglomerate.
4. Febritic grit.
6 & 7. Purplish conglomerate
gritfl, passing up into
argillite.
8. Banded argillite.
10. Purple Slate.
and
Notb. — The conglomerate north-west of the Moel Goronwy felsite appears
to resemble conglomerate 3 in our figs. 1, 2. and 4. The mass shown N.W.
of the synclinal has not been examined by us, so that its similarity is merely
inferred from the strati graphical relations.
syncline on the south-west might be equivalent to the beds occu-
pying the wider curve on the opposite shore ; more probably, however,
all tbe undulating beds on the former side are faulted represen-
tatives of the latter. But the want of exact agreement, together
with the fact that the beds on the rising ground on each side
seem to dip towards the lake, suggest that a fault may very likely
extend along the line of the lake itself. Such a line of disturbance
is shown on the Geological Survey map in the upper part of the
valley.
VII. Comparison op Microscopic Sections.
We have further examined microscopic slices of many typical
specimens. The following brief summary of the details and of our
1 This must be considered hypothetical, until further examination is made
and the dips are recorded. We hare only partially examined the section, but
it seemed to us that a succession was indicated in the conglomerates and grits,
which would agree with our interpretation of the outcrops to the S.W. and of
the section by the lake.
2t2
Digitized by Google
598 PBOP. T. Q. B05XBY AND M18S C. A. RAISIH OJf [Nov. 1894,
conclusions is limited to rocks from the locality of Llyn Padarn1,
which Mr. Blake has definitely grouped with one of his two series.3
I. In the conglomerates or breccias of rather basic materials,
taking specimens from critical parts on both sides of the lake,* we
find these to consist of fragments of the following : —
(a) Ferruginous andesitic or basaltic rocks, recalling sometimes the
character of masses described from the Lleyn. They include
1. Fragments, where lath- shaped felspars, clear, but replaced
by an aggregate of minute minerals, are embedded in a
continuous black opaque ground ;
2. Fragments, where similar felspars occur in a ground speckled
with opacito ;
3. Fragments, with a felsitic cryptocrystalline ground, rich in
ferrite.
Some of these fragments may represent lava with flow-
structure.
(o) Andesitic fragments, containing viridito or chlorite within
crystals or in the groundmass : including
4. Ferruginous rock with some viridite ;
5. Rock with a matrix of viridite, perhaps originally a kind of
tuff.
(c) 6. Andesite or felsite, deficient in iron oxide and viridite.
1 Many more slices hare been examined, and reference to other districts, or
to slices from other rocks in this district, would rather strengthen the case, but
it would extend the statement to too great a length. We may, however, add
that we baTe compared the slices of grits and conglomerates from Mr. Blake's
' Cambrian ' and ' post-Llanberis ' beds in tho neighbourhood of Llyn Padarn
with a number of those from the area between Brithdir and Bangor (Tair-
ffyuon, etc.). Though varietal distinctions exist, to some of which attention ha*
been culled in former papers, these beds on the whole bear a general resemblance
to the clastic rocks discussed in the present communication, and the lava-frag-
ments occurring in the one set can often be identified in the other. Hence it is
more probable that all belong to one and the same period than that they
represent two periods separated by a vast physical break.
Mr. Blake, in an earlier paper (Quart. Journ. GeoL Soc, vol. xlviii. 1892,
pl. vi.), admit* the conglomerate north of Llyn Padarn to be the equivalent of
the Bangor Conglomerate. (It is also referred to by one of us, C. A. Raisin,
Quart, Jouro. Geol. Soc. vol. xlvii. 1801, p. 335.) To us, however, the former
seems very similar to the conglomerate immediately south of the main mass of
felsite on both sides of the lake, which he claims as 4 post-Llanberis.'
3 The specimens were not directly cut to establish this comparison, so that
the preponderance of any one group on one or the other Bide of the lake is often
accidental. The references give the localities of the specimens as marked in
Mr. Blake's figures and maps as nearly as is possible, Quart. Journ. Geol.
Soc. vol. xlix. (18<J3) pp. 441 et seqq.
* A.— East of Llyn Padarn by slate-railway, ' rain-spot ' breccia underlying
supposed line of unconformity. Figs. 1 and 2, g. ' Cambrian.'
B.— East of Llyn Padarn near road north of Faehwen. Fig. 2 about N.W.
of F in Fachvren. 4 Cambrian.'
0. — East of Llyn Padarn by slate-railway. Conglomerate overlying supposed
line of unconformity. Figs. 1 und 2, A. 4 Post-Llanberis.'
D. — East of Llyn Padarn. Ditto. 4 Post-Llanboris.'
E. — East of Llyn Padarn, to bou th-eastward of the top of Y Bigl. Fig. 2,
? about due S. of 23. 4 Post-Llanberis.'
F. — West of Llyn Padarn, hillside above Tan-y-pant. Fig. 7, ? about due N.
of 16. 4 Post-Llanberis.'
Digitized by Google
■
Vol. 50.] OLDER FRAG MENTAL ROCKS IS N.W. CAERNARVONSHIRE. 599
There are gradations, and no absolute separation exists between the
above-named groups, but the fact that these merely minor varieties
recur in rocks at different horizons is a very strong argument for
the view that denudation was proceeding continuously. We find
all the six types of material present in rocks below and above the
supposed break. Pour of the varieties can be recognized in every
slide examined, and five in nearly all the sections. There are also
other points of likeness in the structure of the fragments, such as
slight varieties of fluxional, scoriaceous, and other more microlithic
structures. All these characters are common to the 4 earlier ' and
the 4 later ' series.
In certain finer-grained clastic rocks, where bands of grit
alternate with more compact layers, the materials are evidently of
similar character, although the recognition of minor varieties cannot
be so complete as in the case of larger fragments, and fewer slices
have been prepared from what necessarily would be a less interesting
aeries. Fragments, however, can be recognized of the above-
mentioned types (a) and (b) in slices from 4 Cambrian ' and from
4 post-Llanberis ' rocks, while some of the structures mentioned are
reproduced ; the finer material also is of the kind which would be
formed by the further wear of similar masses. Thus theso banded
rocks can be recognized microscopically (as we have previously
shown that they can macroscopically) both above and below the
supposed break.1 Also they grade into the coarser as well as into
the finer layers, and thus form part of a continuous series.
The still finer gritty or banded argillites cannot, of course, afford
much direct evidence. Still, those assigned to the two ages have a
general similarity, especially noteworthy in the seams rich in
angular fragments of felspar and quartz, and both frequently
present resemblances to the groundmass of the aforenamed coarser
rocks.'
Taking, lastly, rocks formed of more acid material, the frag-
1 G. — East of Llyn Padarn. Slate Railway. Fig*. 1 and 2,/. • Cambrian.'
H— West of Llyn Padarn. Hillside above Tan-y-pant. Fig. 7. ' Poat-
Llnnberifl.'
I —West of Llyn Padarn. Ditto.
2 J— West of Llyn Padarn; near inlet of lake. Figs. 6, 6; 7, No. 11.
'Cambrian.'
K.— East of Llyn Padarn, from syncline by slate-railway. Figs. 1 and 2, d.
♦Cambrian.'
L— East of Llyn Padarn, from syncline by slate-railway. Figs. 1 and 2, c.
•Cambrian.'
M.— East of Llyn Padarn, from syncline by slate-railway. Figs. 1 and 2,
b-d. 1 Cambrian.'
N.— East of L\yn Padarn, from syncline by slate-railway. Figs. 1 and 2,
6-d. ' Cambrian.'
O.— East of Llyn Padarn, near the top of Y Bigl. Fig. 2. * Post-Llanberis.'
P.— East of Llyn Padarn, near top of Y Bigl. Fig. 2. ' Post-Llanberis.'
Q. — East of Llyn Padarn, about S. W. of the top of Y Bigl. Fig. 2. * Post-
Llanberis.'
R.— East of Llyn Padarn, about S.E. of the top of Y Bigl. Fig. 2. * Post-
Llauberia.'
Digitized by Google
600 PROP. T. 8. BONN BY AND MI88 C. A. RAISDf ON [Nov. 1894,
ments both in grits and in the well-known conglomerate1 are
mainly : —
(1) Varieties of felsite which would find their counterparts in
the 4 Llyn Padarn ' mass.
(2) Quartz-grains, often rounded, sometimes corroded.
(3) Felspar-crystals or grains, often twinned.
All these may well be derived from the qnartz-felsite by the
lake.
(4) Granitoid rock, and quartz and felspar, apparently from a
rock of this nature.
(5) Quartzite which has a rather characteristic structure.2
(6) An altered-looking, ofteu schistose mineral. It varies from
pale yellowish to groen, is slightly dichroic, and seems to
give straight extinction. It bears some resemblance to an
altered biotite, but cannot be certainly identified.
The altered mica-like mineral is especially found in two slides
(« post-Llanberis but a small fragment of a similar variety occurs
in one of the finer « Cambrian ' strata west of Llyn Padarn, and a
similar mineral is seen in some of the quartz-felsite slides.' Also
fragments of a spherulitic felsite occur in both sets, e. g. in a
* Cambrian ' grit from east of Llyn Padarn, and in one called
* post-Llanberis ' from west of the lake ; and a similar character,
associated with a perlitic structure, can be identified in a Moel
1 8.— East of Llyn Padarn, synclinal by slate-railway. Fig*. 1 and 2, d.
* Cambrian.'
T.— East of Llyn Padarn, by slate-railway. Figa. 1 and 2, g, h. ' Cam-
brian.'
U, V, W.— Three slides from east of Llyn Padarn. Figs. 1 and 2, i.
X, Y.— Two slides from west of Llyn Padarn, road by Tan -y- pant Cottages.
Figs. 7 and 6, a. • Post-Llanberis.*
Z.— West of Llyn Padarn, by road south of Tan-y-pant Fig. 7. 'Post-
Llanberis.'
a, (3, y.— Three slides from west of Llyn Padarn, hillside above Tan-y-pant.
Fig. 7. ' Post-Llanberis.'
6, f.— Two slides from east of Llyn Padarn by slate-railway. Figa. 1 and
2, a. ' Post-Llanberis.'
2 On examining a specimen from east of Llyn Padarn (from the hillside
above the slate-rat 1 way) we find that it consists of subangular to partly rounded
quartz-grains, which obviously have been slightly augmented by secondary
quartz, though without losing their original outline. Between them, set as it
were in the secondary quartz, are fiakclete of a colourless mica. A few grain*
of felspar have also been present, most of them now replaced by the above-
named mica and quartz, but two or three are unchanged (microcline, plagioclase,
etc.). In the groundmass are several granules of yellow epidote, of pyrite ?,
hornblende?, and possibly rutile, with an opaque whitish decomposition-
product, and two or three rather rounded zircons. The rock obviously was onoe
a somewhat felspathie sandstone. It appears to have been converted into a
quartzite before the pebble was made, and is rather more altered than is usual
with a Palaeozoic quartzite. This also, so far as ono can judge from macro-
scopic observation, is true of the other pebbles.
3 Even some granules of haematite appear to have their equivalents in one
or two of the felatones. (Compare Sir A. Geikie, Quart. Journ. Geol. Soc
vol. xlvii. 1891, Pres. Addr. Proc. p. 99, and T. G. Bonney, Quart. Journ. Geol.
Soc. vol xxxv. 1879, p. 311.)
Digitized by Google
Vol. 50.] OLDER PRA OMENTAL BOCKS IK N.W. CABRNABVOltSHlBB. 601
Tryfaen slide (' post- Dauberis*). The other classes of fragments
make up the bulk of the rocks enumerated, bcth tho * Cambrian •
so-called and tho 4 post-Llanberis.' Very much of the ground-
mass apparently has been derived from the felstone, for in some
eases it is by no means easily distinguished from a crushed variety
of that rock.
To render the comparison more easy, we have separated the
fragments of tho acid from those of a basic type ; but they may
both occur in the same mass, as for instance, in the thinner bands
of conglomerate or of grit at the synclinal by the railway on the
western side of Uyn Padarn.
The results obtained from microscopic examination are thus clear
and definite. Whether we compare rocks below the supposed
unconformity with those above, on one side of the lake, or on the
other, or on both — whether we compare the rocks of more basic or
of more acid material, the coarser or (so far as they afford any
evidence) the finer — the same kind of fragments can be recognized
in both sets. Rocks of very different composition wore being denuded
before the supposed epoch of disturbance, and the same set of rocks
was being worn down after that epoch. It would be a difficulty,
as we have pointed out, if we had to suppose that the felsite was
twice uncovered, but when wo have in addition to believe that the
same varieties of more basic rocks were in each case associated, so
that identical conditions were reproduced before and after the great
interval and interruption, this would be a coincidence suggesting
the necessity for the strongest positive evidence of the uncon-
formity. But at the crucial section, as we have shown, there is
perfect gradation and continuity in the materials. Microscopically,
as macroscopically, the unconformity does not exist.
Discussion.
Prof. Blake was glad that the Authors had attempted seriously
to examine the question dealt with. Criticisms in such a spirit
were in any case of value. The points dealt with in the abstract 1
read to the Society were covered by the remarks in his original
paper, some of which he repeated.
Dr. Hicks said that he could not understand the position now taken
up by Prof. Blake, as the evidence given in the paper clearly showed
that the great felsite-ridge was at the base, and evidently older
than any of tho recognized Cambrian rocks. The Conglomerate
resting on the ridge was sometimes diminished in thickness by
faults and in other places represented by grits ; but it contained
everywhere material derived by denudation from the ridge, along
with pebbles of other pre-Cambrian rocks. On the table were
pieces of this Conglomerate which contained cleaved felstones, and
large pebbles of a granitoid rock exactly like that forming the
1 [This expression, unfortunately, is not quite accurate. I did not read an
abstract, but gave an abridgment of the paper, sometimes reading, but mostly
speaking from notes.— T. Q. B., August, lw4.]
Digitized by Google
f)02 FBAGMENTAL HOCKS IN N.W. CAERNARVON SHIRE* [NOV. 1 894,
pre-Cambrian ridge at Caernarvon. The paper in his opinion gave
the death-blow to tho views put forward by Prof. Blake in regard
to the succession of the older rocks in Caernarvonshire.
Mr. Whitaker also spoke.
Prof. Bonnet replied that if Mr. Blake meant that another
conglomerate was to be seen in the adit at Moel Tryfaen besides the
one described by the Authors, it was in favour of their hypothesis
of a fault. He could not admit that the felsite and purple slate
were * zigzagged together/ as Mr. Blake described. If the Authors
had found the right place, the rock was not felsite but a fclsitio
grit. In the alleged unconformity by the slate-railway, the struc-
ture in the ' rain-spot breccia ' was due to cleavage, not to bedding.
Cleavage often disappeared in passing from finer to coarser strata —
that was a matter of common experience. Moreover, cleavage
could be just traced in the Conglomerate, and was perfectly
developed in some interbanded fine grits or mudstones, a few step?
uphill above the crag depicted. In answer to a question asked,
he might remark that the Authors had carefully avoided the pre-
Cambrian question, as foreign to the immediate issue of their
paper, so he must decline to express his opinion on the subject.
Digitized by Google
Vol 50.]
CARBONIFEROUS DOLERITES AND TUPP8.
603
39. On the Microscopical Structure of the Carbontperous Doleritbb
and Tupps of Derbyshire. By H. H. Arnold-Bbmrosb, Esq.,
M.A., F.G.S. (Read June 6th, 1894.)
[Plato XXIV. & XXV.]
Contents.
Introduction
Table of Outcrops and Mine-heaps
Part I.— The Lavas
1. Olivine.
2. Potluck PseudotnorphB after Olivine.
3. Peak Forest Pseudomorphs after Olivine.
4. Rhombic Pyroxene.
5. Augite.
6. Felspar.
7. Structure of the Lavas.
Part II.— The Fragraental Rocks or Tuffs
Castleton, Outcrop 1.
Brook Bottom, Outcrop 7.
Litton, Outcrop 8.
Dove Hole«, Outcrop 12.
Monk's Dale, Outcrop 16.
Ravensdale Cottage, Outcrop 18.
Miller's Dale Station, Outcrop 19.
Oracknowl House, Outcrop 34.
Ember Lane, Outcrop 39.
Grange Mill, Outcrop 46.
Hopton, Outcrop 63.
Kniveton, Outcrop 64.
Kniveton, Outcrop 66.
As hover, Outcrop 69.
I have, in the first place, to thank Mr. Teall for the suggestion that
I should work out the Derbyshire Toadstooe by the modern petro-
graphical methods. I am not aware that the results of any detailed
examination of the rocks have been published. Mr. 8. Allport
described five specimens from Matlock Bath and one from Bonsall.1
I havo examined his specimens and find them to be much more
altered than the rock is in many places. The Cave Dale rock has
been described and the Tideswell Dale rock has been both described
and figured by Mr. Teall.a
The first person who wrote about the rock and called attention
to its igneous nature was, I believe, Wbitehurst, the clockmaker of
Derby.' He considered it to be intrusive, but it is now generally
admitted to be contemporaneous with the Carboniferous Limestone.
1 ' On the Microscopic Structure and Composition of British Carboniferous
Dolerites,' Quart. Journ. Geol. Sol. vol. xxx. (1874) pp. 629-567.
a 4 British Petrography,' pp. 209, 210, and pi. ix.
3 'An Inquiry into the Original State and Formation of the Earth,' by John
Wbitehurst, 1778, pp. 149 et seqq.
Page
im
606
611
625
Digitized by Google
604 MR. H. H. ARNOLD-
ON THE MICROSCOPICAL [NOV. 1 894,
The rock occupied the attention of many writers previous to the use
of tho microscope in petrography, and various opinions have been
expressed and statements made about the number of beds and the
non -occurrence of lead ore in it. It should be pointed out, that
owing to the vague use of the word * Toadstone ' by miners, their
statements as to the number of beds must be accepted with reserve.
It is now impossible to verify such statements, because most of the
mines are closed. The local name 'Toadstone' is derived either
from the supposed resemblance of the amygdaloidal varieties to the
back of a toad,1 or the word is a corruption of the German
' Todtetein ' (Deadstone) and so called because it was supposed that
no lead ore was found in it.2
Though a mineral-vein is often cut off by the Toadstone, there
are some undoubted cases in which the lead-ore has been worked
in that rock. About two years ago I visited tho Wakebridgo Mine
near Crich, and examined the rock in which the ore was being
worked. It was a much decomposed olivine-dolerite.'
All the outcrops except two occur in the Mountain Limestone.
Near Eniveton are two outcrops of igneous rock among the Yore-
dale Beds (nos. 57-58). According to the Survey memoir they cut
across the shale and limestone, so that their boundaries are faults
or the Toadstone here is intrusive. Sir A. Ramsay considered the
latter view the safer.4 The rocks in the neighbourhood are so con-
torted that it is difficult to say how far these views are correct. I
have not been able yet to spend enough time at the locality to
come to any opinion on the matter.
The spheroidal structure is well developed in many places, notably
in Tideswell Dale, Priestcliffe Lane, New Bridge, and a rude
columnar structure occurs in Cave Dale, near Castleton, and in
Tideswell. Dale.
Where exposures are seen which show its relation to the lime-
stones above and below it, there is no doubt about the age of the
Toadstone. The Geol. Surv. Memoir, p. 123, gives reasons for the
belief that it is contemporaneous with the limestones. According
to the memoir, the Toadstone is never seen to cut across beds of
limestone, and although clay beds below it have been in some cases
baked and caused to assume a columnar structure, as in Tideswell
Dale,* those resting on the Toadstone show no trace of alteration.
The abundance of the amygdaloids in the upper part of a sheet, the
bedded ash near Ashover, and the bedded agglomerate at Hopton
are cited as evidence of its being interstratified with the limestone.
1 ' E.<wai sur l'Oryctograpbie du Derbyshire, par M. Ferber/ quoted by Fauja*
de St. Fond in 1799, 'Travel* in England, Scotland, etc./ vol. ii. pp. 284 et
#cqq.; also J. Farey, ' General View of the Agriculture and Minerals of Derby-
shire,'vol. L (1811) p. 277.
a Green, 'Physical Geology,' 1882, p. 564.
» ' Notes on Orich Hill/ Journ. Derbyshire Archajol. & Nat. Hist. Soc vol. xvi.
(1894) pp. 44-51.
4 Mem. Geol. Surv. North Derbyshire, 1887, pp. 86-87.
8 * On an Altered Clay-bed and Section in Tideswell Dale/ by the Rev. J. M.
Mello, Quart. Journ. Geol. Soc. vol. xxvi. (1870) p. 701 ; also E. Wilson, Geol.
Mag. 1870, p. 620.
Digitized by Google
Vol. 50.] STRUCTURE OP CARBONIFEROUS DOLERITE8 AND TUFFS. 606
Observations in the field confirm the opinion expressed by the
Geological Surveyors. As additional evidence, there are two cases
in which we have a bed of tuff succeeded by a lava-flow, and of the
remaining 61 outcrops 11 provo to be tuffs. Of course in such
outcrops of the Toads tone as nos. 5 & 6, where the relativo position
with regard to the limestone has not been exactly determined, it is
impossible to say whether the rock is intrusivo or interbedded. I
have discovered no proofs of intrusion anywhere.
The Toadstone is found in a district measuring about 25 miles
from north to south and 20 miles from cast to west. The Goo-
logical Surveyors have mapped 60 outcrops, some of which are parts
of the same flow.
The following Table (p. 606) gives a list of these outcrops. I have
applied to each a number, commencing from the north, and the names
of the chief places near which it passes, both for the purpose of this
paper and for future reference and identification.
In column IV. the words 4 Upper ' or 1 Lower ' (with a cross
reference) mean that there is clear evidence that the two outcrops
in question are so related to one another, but it does not follow that
all tho outcrops marked * Upper ' are necessarily on the same
horizon.
The specific gravity has been determined by a Walker's balance
made by How. Two specimens were also weighed with a chemical
balance. They gave 2-86, 2-87 with Walker's balance, and 2-876,
2*890 with the ohemical balance. The determinations were there-
fore *016 and '02 less by Walker's than by the chemical balance.
The eighth column gives some idea of the comparative freshness of
the three principal minerals in the least altered specimen from each
outcrop of lava : thus / denotes that the mineral is fresh or un-
altered, and in the case of olivine that it is altered only along the
cracks ; a denotes that it has undergone a less or greater amount of
alteration, in some cases being entirely replaced by a pseudomorph.
In eleven out of forty-five outcrops fresh olivine is found, in twenty-
six fresh augite, and in thirty fresh felspar, and in ten all the
minerals are found in a fresh state.
There are undoubtedly two beds at least which are recognized by
the Geological Survey, but whether they extend over the whole
district is uncertain. Two may be seen exposed on Chelmorton
Low, outcrops 26, 19; Matlock Bath, 39, 40 and 41, 41, 40 ; Ash-
ford, 31, 30 ; Lathkill Dale, 37, 36; Miller's Dale, 20, 19; Tides-
well Dale, 17, 9 ; Cressbrook Dale, 8 a, 8 b ; on Weathery Low, 15,
14 ; and near Brook Bottom, 7 a, 76.
Outcrops 13, 14, 25, 26, 27, 28, now separated by denudation,
were probably once connected and formed one bed, which would
be the lower one of the district about Millers Dale. Nos. 17, 20.
24 might have belonged to this bed. Outcrops 9, 15, 19, and
perhaps 21 and 22 probably formed the upper bed of the district.
Two beds also appear at Ashford and in Lathkill Dale. There seem
to be, then, two well-marked beds or lava-flows near Miller's Dale
Digitized by Google
c* 1
>> •
Frcehtie
; ^
•oui.vno
1 -
P5
I
Cm
1
o
I
CO
m w
1
* -j O ■L,
.2 c ~ <■>
-° ~ a "3
i t E H
^ C O ~
;^ >-='?
o
CI
©
CI
5 $ 3
ci ci ci
— CI 'C — 1
1 1
-
"©
'- ' L>
1
o
-a
1
-
-
_
2
-3
o.
,> ^ ea
OO CH
fc: f >
sis
> §■
o
cc
"c
■J .
§J
O -* -r r- Q ci t- p
*l CI CI CI CI CI CI CI CI
— -
CC CO
CI CI
oc
Cl
CI
CO
CI
•r coo ©
-t> >-Ci iO I
CI CI CI CI
CC — . r-l ?5 CI "I
O T CI
i
o
•a
I
-=
!
o '
*6
5
a
-
5 >
o
:
o
o
T3
§2
£ « 'a
<- •= P5
ill.
e} <V Z>
r- j ■y ^ >^
^ p _= "~ ^
£ > -as — ©
c w ^ o ■- »-
Ch ^3 3
- CI c?
-r >c i-
Digitized by Google
v.
i :«-> ^ i
• * • • •
• • • • ■
•
*
•
e « o o e a «
Q d q e a
-11
•
lerite.
•
©
c
is ,5
^ Ji H S
-0 ~p J3
o c © ©
c s c g
i
Q
1.1
rite.
ine-do
©
s
c ^
1 1 §
«3 JC «
fc. > t» C
3 — — a
ioooo
5
i 2" 3' • c § 3 3
'ETC*
© © © * v _i
"o o "o '0 .2 "o "o
*5f ' •2'?'?
© © © © H © ©
oooo o5
ts ©
§
2 2 • c 2 S
"o "3 *0 o ~3
^ TJ ' £ "V
© © © £ y
c s c o.S
ooo o
2*
c
©
1
f,
01 C*
Cl ao
S CO-
CM <N
«2
CO
CI
CM
> CD »-'
IS?
CM CM
o
CM
So n s
Ol CM
CI
01 CI
? ? 5
o< Ol o<
© t-O CM
^< ~ »£5 00 W CM ~ — HINCO CO 00
is
1 i
I
o
a
s
1 5
a %~ — « a s-,
is
C-2
3£
c
3
8 §
W
a
o
W 3g*
• * -
0
3
1 1
i I
S'2I
•§
6
•
o
■
o
•
O
H3
c5
4
T3 ^
d d
^0 T3 T3
d
•
O
COCO
O
r-l
CO
1-<
O
8
oi oi ol ot
o5oi
8
Digitized by Google
n "-
t Z
S u
•onuiio
•s
C
o
"a.
5^
:,
•5
-
O C
o
£ AS
(- .5 n
« > .2
0 — o
-r ° "3
1 « A
a a - a
•| f= ;> u
OHOCO
_
T
-
1
t- I*
*" - —
c t
2-2.
i- 4 C
2 ~ e
.2 -- o
> •*■
3
E
7 3 .
= fa
o oo
C'o' •< rr 5 J ^
I
X
.a a c
5 a
^ € s
£ 1
c
© ©
ci ci
3
x
Tl CI
ci ci ci
i-
ci
00 ~. w 1- .
C f- 5 N
ci ?! ro ci
.9 »
CI c»
-ji o
CI Tl tl CI
I—
I —
CI
© CI
t~ i-
© C X -
ci ci ci ci
*-^>
I
35 ?
CI CI CI
CI CI 71
71 — — O
CI CI 71 CI — CI iZ SO o
-
:
tc
-
i
■
«- I- - -C • 5- ©
2 r: ? -Ic
a.:- ^
c
a
- hH
^> 2
c
■5 ^ .
H «
_m r — ^
'C i—i
t
£ — a
'<a = 3
^ ^ 3
- — a,
C U
o
T3
c
-3
c
r
o
«
'J"
J 2
--.
I
-
C .■
ill
P5 ^
3
r:
X
J
4>
L. TJ
a ~
c ^ .
3f s/ 2
~.a* -a 2
o
I
CJ c C rf
^ rs rz
X
—
o
^3
pa
X X
— CI
X X
•
^ X X X ^ ^
— ^1 _
4
EC
cc
I - X ©
CC CO cc
— • ci rc *- ifi o
Digitized by Goqgle
S
« 0
«
• • • »
m m • •
• • • •
• •
•
S
O Q <s e
« «
e
9 8 9 8
9 O
3 3 3 3
EEC C
w « c o
"o O "3 "3
<5 o © ©
a a a a a
O COO 8
i
2
13
515
'SI
.•§.1
5
•c
®
o
1
a
OH
5
|
o t-
?!
II
-<§•
3SS
^ei^»- eo «ceoco coo-* <N»oeo*»
i r
sa 3
a -3
S « e
i-fi
o
o
W -a
3
J8 J3
I *
*i *j »- o o
c
o
1
J"
.00
> a .
a o a
as
~ o
9 O •
&« 3 O
s 3 £ 13
■g 5| S «
c 3* S S'.I'—
z ^ ^ —
J J
o o o c
"3 "3 T3 *T3
* . * ♦
— • CI *M
t- t--
o o o
-3-3-3
4
-3 73
ao
3
2 2 3 3
O & 0> 4)
"o 'c 'o'o
► w > ►
OOOO
5
X
• 'a
SI
■3 -3
55"
3
2 C
1^ si
?5 * • <D
•5 —2 S
CO
00
Digitized by Google
610 MR. H. H. AENOLD-BEHBOSE OH TIIK MICBOSCOPICAL [Nov. 1S94,
and Buxton. There may be three beds or even four. It will be
seen from the Table that the microscopic structure of the rock does
not settle the question. The only way of ascertaining the real
number will be by careful mapping over the whole district, and
working out the fossils in the different horizons of the limestone.
I have been unable to find the following outcrops which are
mapped by the Geological Survey : nos. 11, 32, 35, 51, 55, and 61.
In every case except one, before giving up the attempt, I have
mapped the toadstone-outcrops from the 1-inch to the 6-inch map
and walked carefully over the ground.
Kemp's Hill, Outcrop 11 , is mapped as forming a closed curve or
ring round the hill which lies between Peak Forest and the station of
that name. I have found no traces of toadstone either in the walls
or in the soil. On the contrary, I found that several new quarries
have been opened in the limestone where toadstone is mapped.
The subsoil is of a reddish-brown colour similar to that covering the
limestone in the Small Dale quarries near by, and is not a decomposed
toadstone. There are a number of swallow-like holes in the lime-
stone just outside the ring of supposed toadstone which are similar
to those found in the toadstone between Dove Holes and Peak
Forest Station. I can hardly think that the former can have mis-
led the Geological Survey officers. All the evidence that I can find
is against there being a bed of toadstone on Kemp's Hill.
Dove Holes, Outcrop 12. — This I have found, but there are doubts
as to whether it is an igneous rock. See under Tuffs.
Taddington Field, Outcrop 32. — I have only paid one visit to
this place since mapping the rock, and have been unable to find the
outcrop where marked. In the Geological Survey memoir it is said
that the outcrop is difficult to find.
Ditch Cliffy near Bakewell, Outcrop 35. — In a field to the E.
of the road are some large blocks of dolomitized limestone which
might be taken for toadstone, before they are broken into. Lime-
stone is seen in several places on the bill, and in the soil by the
roadside. There are two or three blocks of toadstone in a wall
near, and one in the road-embankment amongst pieces of limestone
and chert. These blocks may have been brought from the Lathkill
Dale upper bed no. 36, a few fields away, or they may be from the
drift which covers the surface in the neighbourhood of Bakewell,
especially at the cemetery. I found a granite-boulder less than
£ mile from this supposed outcrop. I question whether there was
ever any outcrop of toadstone here.
Minnimjlow, Outcrop 51. — Where the outcrop is mapped, the
fields are ploughed or covered with grass. A few blocks of toadstone
are found in the walls, but stronger evidence than this is necessary
to prove the existence of a bed.
Tissington, near Ashbourne, Outcrop 55. — I have not visited this
particular locality since I obtained the 6-inch maps. On two visits
I have failed to find it. The ground is much covered with drift, and
some pieces of toadstone in it might have been taken for indications
of a bed.
Digitized by Go
Vol. 50.] 8TBUCTURK OF CARB05IFEB0U8 D0LBBITE8 AND TUFFS. 611
MiddUton, Outcrop 61. — On the road to Rider Point 1 have found
no exposure, the ground being covered with grass.
North of Fairfield Common, near the old racecourse (outcrop
13), a small strip of toadstone is mapped by the Geological Survey.
Every exposure shows limestone. A small quarry has lately been
made for the mending of walls. The section exposed shows 1 foot
of soil, 2 feet of clayey soil containing a few lumps of toadstone, and
then limestone in almost horizontal beds.
1 am aware that the above evidence, except that regarding out-
crops 11 and 35, is of a negative kind, and that the fact of my being
unable to find the outcrops does not prove that they never existed.
It is possible that some of them may have been exposed at one
time, and that the exposures are now hidden.
1 have added to the list three outcrops not mapped by the
Geological Survoy.
Brook Bottom, Outcrop 7, is mapped by them as one bed. It
is clearly two — a tuff and a lava separated by beds of limestone.
See under Tuffs, no. 7 a.
Litton, near Tide&wtll, Outcrop 8. — A lava and a tuff separated
by limestoue. See under Tuffs, no. 8 6.
Potluck, Outcrop 60. — This is exposed in a field in front of the
rifle-target, and is probably continuous with that at Pittlemere,
no. 6. Both are ophitic olivine-dolerites.
In addition I have examined specimens from Wakebridge Mine and
from the following mine-heaps : — Glory Mine, Crich ; Elton, Wheel
Hake, and Black Hillock : and have descended three mines, viz..
Mill Close, Wheel Bake, and Wakebridge. Only in the last have I
Been the toadstone in place. In the New Key Cavern at Matlock
Bath I have seen blocks of toadstone which were not in situ. I
have also examined several specimens of the rock from other places
which were not in situ. My object has been to examine every occur-
rence of the rock in detail from as fresh specimens as possible.
For convenience, this paper is divided into two parts : The Lavas
(none of the rock having yet been proved to be intrusive) and Tho
Fragmental Bocks or Tuffs.
Part I.— The Lavas.
1. Olivine.
Olivine occurs mostly in the form of phenocrysts and groups or
nests of crystals. The phenocrysts vary in size from 5 millim. in
length, down to the smallest measured, *06 x *08 mm. Of fifteen large
ones measured, ten are over 2 mm. in length, four over 3 mm., and
one over 4 mm. The outline is generally very well marked, giving
the usual six-sided sections with acute angles between tho domes.
Sections parallel to (100) and (010) are found showing a positive
and negative bisectrix, and others perpendicular or nearly per-
pendicular to an optic axis. Tho outline is often well preserved
when the olivine is altered to oxide of iron or some other mineral,
Q.J.G.S. No. 200. 2u
Digitized by Google
612 MR. H. H. A RNOLD-BE Jf BOSS ON THE MICROSCOPICAL [NOV. 1894,
so that when a hand-specimen of rock is much decomposed it is
easy to find the olivine-pseudomorphs with a lens. Fresh olivine
occurs in twenty-eight thin sections from eleven outcrops. In most
of these the greater part is entirely unaltered, except for a slight
discoloration in the cracks, most of which are rectilinear. The
curved cracks which are present, in some cases combined with an
alteration on the outside of the mineral, result in large granules of
olivine without crystalline form. Some of the crystalb are corroded
and eaten into by the groundmass, and thus contain felspar-laths
and augite in granules.
In some specimens the size of the crystals varies considerably.
In one from a basalt near Chelmorton, outcrop 19, there are a
number of small ones perfectly bounded, and ombedded amongst the
augite and felspar of the groundmass. One measures -08 x *06 mm.,
and shows a bisectrix perpendicular to the section. The largest
measure about '55 x '4 mm.
The olivine often occurs in groups up to 5 mm. in diameter, con-
sisting of two or three or even eight or nine individuals. A speci-
men from Tideswell Dale Quarry, outcrop 17, contains a group of
eight individuals whioh fit closely together but extinguish in
different positions. Two of them appear to form a twin, the angle
between their directions of extinction being 70°. Such groups are
common.
A specimen from a basalt near Blackwell, outcrop 14, shows an
interpenetrating twin, the two individuals being clearly marked in
polarized light. The acute angle of one is about 65°, and that of
the other about 73°. Both sections show a bisectrix, though not
very clearly. The, greater axis of elasticity of the section is in
both individuals at right angles to the long axis. The angle between
the long axes of each is 55°.
In another case the angle between the directions of extinction of
the two individuals is 57°. Several cases occur like the following.
Two individuals almost rectangular in section, the dome faces
absont, are divided by the traoe of the plane of composition. The
section of one individual is at right angles to an optic axis, and that
of the other extinguishes at an angle of 15° with the dividing-line.
In another case one extinguishes parallel to its length, and the
other at 25° with the dividing-line.
The olivine is replaced by iron oxide, calcite, serpentine, chlorite,
and a mica-like mineral. The iron oxide is generally opaque. In
one slide it is transparent dull red, and appears the same in
polarized as in ordinary light It is not dichroic, and shows no
axial figure in convergent light : it is thus distinguished from
olivine coloured by iron. The calcite is sometimes clear and com-
posed of large crystalline pieces, at others doudv, and shows
aggregate polarization. The only pseudomorphs after olivine which
require any description are two which are found to a very lanre
extent in several outcrops. For convenience, I have called them the
Potluck and Peak Forest pseudomorphs.
Digitized by Google
Vol. 50.] STRUCTURE OP CARB0H1FEB0U8 DOLERITE8 AND TUFFS. 613
2. Potluck Pseudomorphs after Olivine.
In an ophitic olivine-dolerite from Potluck, outcrop 60, tho
olivine is replaced by a lamellar greenish-yellow or reddish-brown
dichroic mineral. The greatest absorption takes place when the
traces of cleavage are parallel to the short axis of the polarizer. A
pseudomorph which shows neither cleavage-cracks nor dichroism
gives in convergent light coloured rings and a bisectrix at right
angles to the section. The plane of the optic axes is at right angles
to the length of the original olivine-crystal, the angle between the
optic axes is very small, and the double refraction negative. As a
rule a pseudomorph behaves as a crystallographic individual, and not
as an aggregate. Tho traces of cleavage are generally parallel to
the length of the crystal. In the case of two pseudomorphs, each
consists of two or more portions of the mineral differently orientated.
In one the outer portion is of a green colour without dichroism,
giving an optic axis outside the field and coloured rings in con-
vergent light. It contains two isolated kernels with cleavage
parallel to the length of tho crystal. The other (see PL XXIV.
fig. 3) consists mainly of the yellow mineral with cleavage parallel
to its length, and polarizes in colours of the 1st and 2nd orders.
It contains two isolated kernels cut perpendicular to the acute
bisectrix. No fresh olivine occurs in the slide, nor has any been
found in this outcrop.
In a specimen of more weathered rock from the same locality the
augite and felspars are partly altered. The pseudomorphs of olivine
have good crystalline boundaries, and are often entirely enclosed in an
ophitic plate of augite. They are similar to those described in the
previous specimen. They are yellow when the traces of cleavage
are at right angles to the short axis of the polarizer, and brown
when these arc parallel to it One extinguishes at an angle of 37°
with the length of the crystal, and shows coloured rings and a
nearly straight axial arm.
In a hand-specimen of the same rock glistening faces of a bronze
or reddish-bronze colour are seen, having the characteristic outline
of olivine and attaining sometimes a length of 4 millim. Examined
with a lens they arc seen to possess cleavage, and, on the glistening
feces, the straight and curved cracks usual in olivine. The cleavage
is easy in one direction, and flakes are readily detached with a
knife. They often break at right angles to the cleavage-planes
along the cracks. When mounted, the thin flakes appear brown or
brownish-yellow by transmitted light. In convergent light they
show a biaxial figure with a small angle between the axes, and
negative double refraction. They are sometimes almost uniaxial.
When a fragment does not lie on the cleavage-plane it shows
dichroism, the greatest absorption taking place when the short axis
of tho polarizer is parallel to the traces of cleavage
Similar pseudomorphs are found in outcrop 42, near Upper-
wood on Masson Hill. The felspars are slightly turbid, and no
fresh augite or olivine is present. A six-sided section is bounded
2u2
Digitized by Google
614 MR. H. H. ARMOLD-BEMROSE OK THB MICROSCOPICAL [NOT. 1S94,
by the faces (010) (110). The angle (110) A (110) is 130°. It is
subtended by the traces of cleavage, which are therefore parallel to
100, the macropinacoid of the original olivine. In another section
the cleavage-traces subtend the angle 135°. Yet another section
gives an angle of 77° between the dome faces. This is the angle
for olivine in sections parallel to the brachypinacoid (010). The
cleavage-traces are parallel to the length of the crystal and therefore
to the C axis. Combining these results, it follows that the planes
of cleavage are parallel to the macropinacoid, as in the case of
iddingsite described by Lawson. A pseudomorph is often composed
of several minerals which are arranged in zones parallel to the
outline of the crystal. We have an outer zone of the mica-like
mineral, with an inner portion of calcite and oxide of iron ; or an
outer zone of iron oxide, followed by a thick one of the mica-like
mineral, and this again by a thin zone of iron oxide and a nucleus
of calcite. All traces of the original oli vine-cracks arc lost, but the
pseudomorph sometimes contains wide cracks filled with calcite. In
some cases the olivine is replaced by iron oxide, with or without an
outer border of chlorite or serpentine — pale and slightly dichroic,
the fibres being irregularly arranged.
A specimen from New Bridge, near Ashford, outcrop 30,
contains pseudomorphs similar to those from Potluck, except that
most of the original cracks in the olivine aro filled with iron oxide.
In a more highly altered specimen (see PL XXIV. fig. 4) the pseudo-
morphs are dark green for rays vibrating parallel to the short axis
of the polarizer, and light green or faint yellow for rays vibrating at
right angles. The double refraction is strong, and the polarization-
colours are similar to those of biotite. The cracks are filled with
iron oxide, which has in some cases replaced more or less of the
olivine nucleus. Cleavage-flakes taken from a hand-specimen behave
much as those from Potluck. In several sections the cleavage-cracks
subtend angles varying from 134° to 126° (110 A HO), so that the
traces of cleavage are parallel or nearly parallel to the macropinacoid.
The whole pseudomorph has not always the same optical orientation
throughout. In a section which gives an acute angle of 71° between
the traces of the dome faces, the greater portion gives an acute
bisectrix perpendicular to the section, and the plane of the optic
axis is parallel to the trace of one of the dome faces. It contains
three patches with dichroism and cleavage parallel to the length of
the crystal.
3. Peak Forest Pseudomorphs after Olivine.
In Dam Dale, close to the village of Peak Forest, there is a good
outcrop (no. 4) of ophitic olivine- dolerite. Seven thin sections have
been examined. In the most weathered ones the augite is little
altered, but the felspars are turbid. Pseudomorphs of olivine
similar to those at Potluck are found. Instead of behaving as a
crystallographic individual, the replacement-product sometimes
consists of fibres irregularly arranged, in other cases part of the
Digitized by Go
Vol. 50.] STRUCTURE OP CARBON I FEBOU8 DOLERITBS AND TUFFS. 615
pseudomorph consists of these fibres, and part of tho lamellar
mineral. Cleavage-flakes behave like those from Potluck.
There is also a second kind of pseudomorph which is found only
in the less altered rock. Several of the larger olivines are entirely
replaced by a pale yellow mineral, with traces of cleavage which are
parallel to the long axis of the crystal, but which do not always
run through its whole length. The cracks are filled with and
bordered by a clear yellow substance (a), and this in turn is bordered
by a pale yellow one (6). Both are bounded by lines parallel to the
crack, except where two cracks meet, when b fills up tho triangular
space botween them ; or where two parallel cracks are near to-
gether, when 6 fills the space between them. Both aro dichroic,
a becoming a darker yellow when the short axis of the polarizer is
parallel to the length of the crystal, and 6 being yellow when
the short axis of the polarizer is perpendicular to the length of the
crystal, and a 4 solid -looking bluish-green when it is parallel. Both
a and b extinguish together over tho whole crystal, parallel to the
long axis of the section. In some pseudomorphs the mineral is
non-dichroic, and extinguishes at an angle of 40° or 46° with -the
length of the olivine-crystal.
An olivine-crystal, more than half of which is unaltered, has
the plane of tho optic axes at right angles to its length. The
cracks are bordered by a, which is non-dichroic and yellow, and
a in turn is bordered by b with slight dichroism. Both these
substances become extinct parallel to the length of the crystal, no
matter inTwhat direction the cracks run. The green substance (6)
is followed by an irregular zone of partly altered olivine, which sends
out shoots or fangs into the fresh oli vine-nuclei. Sometimes the
green substance is non-dichroic, and has no traces of cleavage.
Examined under convergent light, with a -j^-inch immersion-lens,
both a and b show in such cases the emergence of a negative
bisectrix, the angle between tho optic axes being very small.
Cleavage-flakes taken from the outer and inner portions of a hand-
specimen were examined. When non-dichroic, they give in con-
vergent light an almost uniaxial figure with coloured rings havin«r
negative double refraction, tho acute bisectrix being ijerpendicular to
the plane of cleavage. In some fragments both the yellow and
green kinds are seen, showing that they do not easily become
detached one from the other. The cleavage is seldom very perfect,
and the fracture is often fibrous.
The cleavage (when it occurs) is often parallel to the macropinacoid
of the olivine, as in the case of the first kind of pseudomorph or that
found at Potluck and other places above described. Oli vino-nuclei
showing the emergence of a positive bisectrix at right angles to the
section, and therefore cut parallel to the macropinacoid, polarize in
green and greenish-yellow of the first order. In such cases the
pseudomorphous parts are not dichroic, and show no traces of
cleavage. Nuclei cut parallel to the negative bisectrix and therefore
parallel to the brachypinacoid, polarize in yellow and blue of the
first order. The pseudomorphous part is dichroic, and polarizes in
Digitized by Google
61 C MB. H. H. AR>*OLD-BEMBOSE OK IDE M1CE06COP1CAL [NOT. 1894,
blue and green of the first order and green of the second : the slight
traces of cleavage, and tho fibres, where present, are parallel to the
length of the crystal. It follows that the pseudomorphs posses*
slight cleavage in planes parallel to the macropinacoid of the
olivine.
The Potluck and Peak Forest varieties of pseudomorph are
also found in outcrop 39, Nealow Lane, near Matlock. Both the
ophitic and granular augite occur. The felspars and augite are
generally fresh. I have collected specimens of rock of both kinds
of structure which can be arranged in two series, each being similar
to those of the Peak Forest rock above described. The most altered
in each series give cleavage-flukes like those from Potluck, the
olivine being replaced by the mica-like mineral, and the least
altered contain nuclei of fresh olivine surrounded by the Peak
Forest variety of pseudomorph. In one thin section of the ophitic
rock serpentine also occurs in the olivine-cracks. In tho same
section we have the Peak Forest pseudomorph. In the freshest
specimen there is none of the dichroic mineral, and the olivine is
altered to serpentine along the cracks. The question we have to
discuss is whether the Potluck pseudomorph is a replacement of
olivine by biotite or some mineral similar to it, or by the mineral
called iddingsite, or by somo other mineral.
Prof. A. Kenard 1 describes the replacement of olivine by mien in
the rocks of Platform Island. The pseudomorphs have the colours,
absorption, and extinction of biotite, and sections parallel to the
cleavage exhibit a black cross with negative double refraction. The
replacement of olivino by leaves of biotite is described by J. J.
Sederholm.2 M. Schuster 3 describes the partial replacement of
olivine by biotite in an anorthite-gabbro from Birchville, California.
H. von Foullon 4 describes the replacement of olivine by biotite in a
molaphyre. The only proofs he adduces are its colour, dichroism,
and parallel fibres. Nuclei of olivine often remain unaltered.
Bosenbusch* describes pseudomorphs of olivine with leaves parallel
to (010) very pleochroic, the greatest absorption being parallel to
the leaves. The colour is between iron glance and pscudo-brookite.
He say 8 that it lias not been proved whether it is a red colouring of
olivine with clearer laminations parallel to (010) or a new sub-
stance. Dana 0 states that olivine sometimes becomes brownish or
reddish-brown and iridescent. It also splits into thin lamina? as
the change goes on, sometimes so as to resemble a mica. Prof.
Iddings describes the alteration of olivine7 to a fibrous material
1 Report of 'Challenger' Expedition, rol. ii. (1889) pt vii., Petrology of
Oceanic Inlands.
9 ' Studien iiber archaische Eruptivgesteine aus dem audweetlicben Finn land,'
Techerm. Min. u. Fetr. Mitth. rol. xii. (1891) p. 106.
3 Neuee Jahrb. Beilage Band v. (1887) p. 520.
* •Ueber Eruptivgesteine von Recoaro, Tacberm. Min. u. Petr. Mitth. vol.ii.
(1880) p. 481.
5 ' MikroskopUche Physiographic,' rol. ii. (1887) p. 489.
• • System of Mineralogy,' 1875, p. 258.
7 'Geology of the Eureka Diatrict,' U.S. Geol. Surr. Mon. vol. xx (1892)
pp. 888-390.
Digitized by Go
Vol. 50.] STRUCTURE OF CaHBOHIPBBOUS DOLEBITBS AND TUFFS. 617
which runs in parallel lines throughout tho crystal. The fibres
have a light-yellow colour at first, which deepens into a reddish-
brown or blood-red as the decomposition proceeds ; they polarize
brilliantly and show sometimes a faint pleochroism. Sections
parallel to the cleavage-planes give in convergent light a nearly
uniaxial interference-figure, and the plane of the optic axes is per-
pendicular to the direction of the fibres. According to his illus-
tration, the fibres appear to run at right angles to the length of
the olivine-crystal. Part of the olivine is often unaltered. In one
case he thinks that this mica-like mineral is probably a foliated
crystalline form of serpentine, namely, thermophyllite.
Lawson 1 describes a similar mineral which he does not consider to
be an alteration-product of olivine (no fresh olivine is found in his
rocks) and to which he gives the name of ' iddingsite.' It has the
same crystalline form as olivine, and the planes of cleavage correspond
to the macropinacoid of that mineral. Cleavage-plates are biaxial,
the plane of the optic axes is parallel to the C axis of the olivine
and perpendicular to the cleavage-planes. The interference-colours
are almost like those of muscovite. In thin sections the mineral
ranges from a deep chestnut-brown to a citron-yellow or clear
yellowish-green. As in the case of the mineral described by Iddings,
fragments heated in hydrochloric acid soon lose their colour, the
iron being extracted, but their optical properties remain unaltered.
As a result of qualitative chemical tests Lawson describes iddingsite
as a hydrated non-aluminous silicate of iron, lime, magnesia, and
soda.
Mr. Teall showed me a thin section containing iddingsite. This
mineral had outlines similar to those of olivine, but appeared almost
opaque in thin sections, and more like haematite. The Derbyshire
mineral is always very transparent.
Mr. Allport 3 describes a dolerite from Duncarnock in which the
olivine is ** partly converted into haematite," the exterior being of
a light red colour, often iridescent, and splitting into thin laminae.
I have examined his specimens now in the Natural History Museum,
South Kensington. In several thin sections aro pseudomorphs
consisting of a fibrous or lamellar dichroic mineral something like
the Upperwood pseudomorphs. In a few cases they show rings,
and the arms of a cross in convergent light. (See thin sections,
nos. 1523, 1524, 1526, Nat. Hist. Museum.)
The Potluck pseudomorph is biaxial, with a very small axial
angle, has negative double refraction, and often the colour and
strong double refraction of biotite in thin sections. As in tho case
of iddingsite, it behaves generally as a crystallographic individual,
and not as an aggregate. The cleavage- planes are also, in every
case whero I have been able to apply any test, in thin sections,
parallel to the macropinacoid of the original olivine.
1 'The Geology of Carmelo Bay,' University of California, Bulletin of the
Department of Geology, May 1893, Lawson and Posada.
* ' On the Microscopic Structure and Composition of British Carboniferous
Doleritea,' Quart. Journ. GeoL 8oc. toI. xxx. (1874) p. 541.
Digitized by Google
618 UK. fl. H. ARN0LD-BEMR03E ON TIIE MICROSCOPICAL [Nov. 1 894,
It differs from iddingsite in having the plane of the optic axes
generally perpendicular to the c axis (001) instead of the 6 axis
(010) of the olivine. Id one case it is perpendicular to the b axis
and ill another parallel to a dome face. Another difference is that
sometimes various parts of a pseudomorph, though behaving as
crystallographic individuals, have a different optical orientation.
These variations, and the occurrence of fresh olivine in two of the
same outcrops, though not in the same specimens as this pseudo-
morph, point to the latter as being a replacement of tho olivine,
and not an original separation from the magma. This view is
confirmed by the occurrence of fresh olivine-kernels with the cracks
altered to serpentine, and the olivine also partly replaced by the
Peak Forest kind of pseudomorph in the Pittle Mere outcrop, which
was probably continuous with the Potluck outcrop.
Cleavage- Bakes from the most altered specimens of the Potluck
rock were detached by the knife, and separated from fragments of
other minerals under a low power. They are not elastic like mica,
but are brittle, often, though not always, breaking along the cracks
of the original olivine. Treated with dilute hydrochloric acid on a
glass slide and warmed, they soon change from red to yellow and
become colourless. They lose their dichroism, but flakes lying on
the cleavage-plane still show an almost uniaxial figure. If the
action be continued a little longer, they become isotropic. When
heated in the closed tube, a little water is given off.
Mr. L. Archbutt, F.C.S., F.I.C., kindly tested some of the flakes
for me and obtained the following results : —
u The quantity of mineral received for analysis weighed about
11 1 milligrammes. Six and a half milligrammes were finely
powdered, and digested with a little pure hydrofluoric acid and
a small drop of sulphuric acid in a platinum crucible, at a gentle
heat for some time, and then evaporated to dryness and heated to
faint redness. The residue was dissolved in hydrochloric acid,
which gave a clear solution ; this was diluted with a strong solution
of hydrogen sulphide, and a trace of brownish precipitate mixed
with sulphur was filtered off. The sulphuretted hydrogen was
expelled by evaporation, the iron oxidized by a few drops of bromine
water, and the excess of bromine evaporated off. A slight excess of
ammonia was then added, which produced a red precipitate : this
was tested for alumina. It was dissolved in hydrochloric acid and
boiled with pure potash in excess, which threw down a compara-
tively large precipitate having the colour of pure ferric hydroxide,
which was not further examined; the filtrate was evaporated with
excess of pure solid ammonium chloride, and a comparatively fair-
sized precipitate of alumina was thus obtained, which was not
further examined. As potash purified by alcohol always contains
traces of alumina, the precaution was taken of testing rather more
of the potash than was used in the analysis, in tho same way,
but the amount of alumina obtained was insignificant. The filtrate
from the ammonia precipitate was mixed with a few drops of a
strong solution of hydrogen sulphide, but no precipitate of manganese
Digitized by Go
Vol. 50.] 8TKUCTURE OF C \ RBONIFEBOU8 DOLBBITES AJTD TUFFS. 619
or zinc sulphide was obtained. A few drops of ammonium car-
bonate were then added, which produced no precipitate, neither did
ammonium oxalate, after waiting long enough for any precipitate to
appear; the absence of lime was therefore inferred. On adding
ammonium phosphate, a small precipitate of ammonium-magnesium
phosphate was obtained, which was filtered off, and after removing
phosphoric acid from the filtrate by lead, and the excess of lead by
sulphuretted hydrogen, and then evaporating to dryness and heating
to expel ammonium salts, the residue gave a decided reaction for
potassium when tested by platinum chloride, and a vory decided
reaction for sodium by the flame-test. Another 5 milligrammes
of the mineral were rubbed to a powder with 10 milligrammes of
fluorspar free from silica, and gently warmed in a very small platinum
crucible. A drop of water in a loop of platinum wire was supported
within the crucible a little above the surface of the fluid mixture,
and an unmistakable precipitate of silica was formed in the drop.
Tho whole analysis was carried out in platinum, and on account of
the minute quantity submitted to examination, every care was taken
to use pure reagents and those in the minimum proportion necessary.
The oxides found, besides silica, were iron oxide in comparatively
large quantity, a fair amount of alumina, a small quantity of magnesia,
and small quantities of soda and potash. The estimates of relative
proportion can of course only be regarded as rough guesses."
These results differentiate it from iddingsite, which, according to
Lawson, is non-aluminous, and contains lime, whilst the Potluck
mineral contains potash and alumina, but no lime. The qualitative
analysis points rather to a biotito ; the optical properties also a?ree
with those of an almost uniaxial mica. Only its brittleness and
want of elasticity make it differ physically from biotite, though
Rosonbusch 1 says that the elasticity of cleavage-flakes becomes less,
even to brittlenoss, in phlogopites and biotitos, and is often quickly
lost when biotite begins to alter to chloritic aggregates. The optical
axial angle is too small, and the pleochroism is too great, for bastite
or for antigorite.
Sprodglimmer and chlorite are the only minerals which have a
like development of cleavage in kind and degree.3 Of the former
group xanthophyllite and clintonite, which have negative double
refraction, have only moderate pleochroism and are hardly attacked
by acids. The double refraction of chlorite is too feeble.
The Peak Forest pseudomorph, though differing in appearance
from the Potluck one, has the same optical properties. The only
difference is in the colour and small degree of cleavage. It un-
doubtedly replaces olivine. The colour is green and yellow in the
same crystal, while that from Potluck is generally red or green, or
yellow throughout. In two outcrops we have the two kinds of
pseudomorphs, though not together in the same thin section. I am
inclined to think that the Peak Forest pseudomorph is a transition-
stage towards the formation of the Potluck pseudomorph. We
1 Mikr. Phymogr. vol. i. (1885) p. 476.
3 Ibid.
i
Digitized by Google
620 MR. H. H. ARKOLD-BEMROSB ON THE MICROSCOPICAL [Nov. 1 894,
should thus have the change proceeding from the cracks of the
original olivine, in a direction parallel to the length of the crystal,
and not normal to the cracks, as in the case of the alteration to
serpentine. The whole olivine-crystal is at length replaced by this
mineral, which is yellow along the cracks and green in the remaining
parts. More perfect cleavage is developed, the iron becomes oxidized,
colouring the mineral red instead of green and yellow, and we have
the mica-like mineral as a rcsultiug product, the cleavage- planes
being parallel to the macropinacoid and the plane of tho optic axes
often perpendicular to (001).
The mineral described by Prof. Iddings is evidently a pseudomorph
of olivine. Lawson considers that iddingsite is not a pseudomorph
of olivine, that it is separated from olivine by its chemical, optical,
and physical characters, and states that no trace of olivine or its
ordinary decomposition-products has been detected in his thin
sections. In the case of the Derbyshire mineral the same remarks
would hold good, if we only had specimens from Potluck and Upper-
wood to deal with (even in these outcrops, if the rock were quarried,
fresh olivine might be found in less altered portions). But we
have the same mineral associated with olivine in two other outcrops.
It may be possible, therefore, that iddingsite is a pseudomorph or
replacement of olivine, but that the replacement has extended
throughout the whole of the rocks in question.
In the absence of a quantitative analysis of the Potluck pseudo-
morph, we cannot be certain whether it is a mica. So far as the
present evidence goes, it would appear to be a mineral allied to
biotite or to clintonite, and may be the same as that which Prof,
ltenard considered from its optical properties to be biotite. At
present I prefer to call it a * mica- like mineral replacing olivine.'
4. Rhombic Pyroxene.
This mineral resembles that in the lava of Eycott Hill described
by Prof. Bonney as altered enstatite.1
Mr. Teall kindly lent mc several thin sections of the Eycott Hill
rock for comparison. The pyroxene in the Derbyshire rock is pale
green or yellow in transmitted light; longitudinal sections are
more or less pleochroic, the absorption being greatest when the
traces of cleavage and the length of the section are parallel to the
short axis of the polarizer. Extinction always takes place parallel
to the length of the section.
The mineral occurs mainly in three localities. A specimen from
Staden Low, outcrop 29, contains both individual crystals and
groups of crystals. The largest crystal measures 1x4 millim. It
has traces of cleavage parallel to its length, behaves as above stated,
and gives pale yellow polarization -colours between crossed nicols.
One individual of a group of about 12 gives an eight-sided section.
The angles between 3 consecutive pairs of adjacent sides arc 134°,
1 Geol. Mag. 1886, pp. 76-80.
Digitized by Google
Vol. 50.] STRUCTURE OF CARBONIFEROUS DOLEM 1 ES AlfD TUFFS. 621
130°, and 1 30°. In convergent light an optic axis is often seen to
be outside the field of view. Other specimens from the same out-
crop do not contain this mineral ; it is probably altered to calcito.
The rock also contains pseudomorphs of olivine, two generations of
felspar little altered, magnetite or ilmenite, some interstitial matter,
various alteration-products, but no traces of a monoclinic pyroxene.
Sandy Dale, Outcrop 24. — Some sections of pyroxene in a largo
group are yellow, and others pale green by transmitted light. The
former polarize in a bright yellow, and the latter in a dark grey tint.
The former are dichroic, giving two shades of yellow, and the latter
two of green. The former show in a convergent light the arm of a
biaxial figure and sometimes coloured rings, the latter are nearly
perpendicular to an optic axis. This mineral often occurs in groups
of two or more individuals : three slides out of the four contain it.
In the Sandy Dale rock are pseudomorphs of olivine, but there is
no augite, and it differs from the Staden Low rock in not always
having two generations of felspar. On the whole, the rhombic
pyroxene is found more often in groups than in the specimens of
the Eyecott Hill rock which I examined. It possesses not only
a better crystalline outline, but behaves more often as a crystal, and
unlike an aggregate pseudomorph, tho whole extinguishing together.
The cleavage is not so well marked, and the fibrous and confused
structures are present in a less degree, and only in the more altered
specimens.
A small portion of the Sandy Dale rock was pounded and passed
through a sieve of 80, but was stopped by one of 120 meshes to the
inch. A number of fragments of a slightly dichroic green mineral
were thus obtained. One only gave a negative bisectrix, with a
small angle between the optic axes. This is probably bastite.
The rhombic pyroxene also occurs in some specimens of the Cave
Dale rock, outcrop 2, whilst in others there is comparatively
fresh augite in grains. Small traces of it are also found in outcrops
23, 27, 28, 31, 37, and 48, and in 14 at the entrance to Chee
Tor Tunnel.
We have, therefore, in these rocks a rhombic pyroxene with
cleavage poorly developed, which in some cases is altered to bastite.
5. Augite.
This occurs in large ophitic plates, large and small phenocrysts,
small irregular grains, and in prisms which give lath-shaped
sections.
The ophitic plates vary in size from 7*5 mm. in length and from
5 mm. x 2'5 mm. downwards. The large plates enclose many felspars
and also oli vine-crystals, which are more or less altered along the
cracks, though the augite appears quite fresh. This structure runs
throughout the slide, so that the whole of the augite has crystallized
last and formed the groundmass. Although these plates have no
crystalline boundary, cleavage-cracks are often well developed in
them, In some sections the sets of cracks are nearly at ri^ht
Digitized by Google
622 MB. II. H. ABNOLD-BEJfBOSE ON THE MICB0SCOPICAX [Nov. 1 894,
angles one to another, and the direction of extinction bisects the
angles between them. These are nearly perpendicular to the
C axis. Others have fine parallel cracks which often ran in the
direction of the length of the plates. They appear in the different
portions into which a plate is divided by the felspars. If they re-
present the usual prismatic cleavages, we have sections out of the
prism zone. The augite often extinguishes at large angles with
these cracks. After measuring a number of angles of extinction, I
find that the largest which the axis of least elasticity of the section
makes with the cleavage-cracks are 40°, 42°, 45°, and 52°. The
angle c/\y is therefore 52° or more. Amongst the ophitic plates are
many twins. In some cases, both individuals possess cleavage-cracks
parallel to the trace of the plane of composition, and extinguish
symmetrically with regard to it. These sections are out of the
prism zone, and the plane of composition is (010). I have measured
the angles which the direction of extinction of each individual
makes with the t winning-line, and the greatest I have found is 45°.
In these plates the angle c/\y is 45° or more.
Some small plates of augite enclose one or two felspars, or have
the end of a felspar sticking into them. They sometimes occur
with the ordinary granular augite, and are distinct from the true
ophitic structure.
The phenocryst8 are of the usual form, and the sections are often
bounded by six or eight sides. The largest measured is 1*65 x 1*20
mm. Some of the biggest crystals are corroded, and others contain
portions of the groundmass. The hour-glass and the zonal struc-
tures are very frequent. The outer portion of . an individual of a
twin crystal often extinguishes differently from the inner portion.
As in the case of olivine, there are many groups the individuals of
which can only be distinguished in polarized light. The smaller
phenocryets are similar to the larger ones, and their boundaries
quite as well defined.
The lath-shaped sections have a well-defined outline, and some-
times cleavage-cracks parallel to their length. They often extin-
guish when the cross-wire is inclined at an angle of about 45° with
their length. They are distinguished from untwinned felspars by
their polarization-colours. I have measured a number of angles
made by the least axis of elasticity with the long axis of the prism,
and the following are the greatest: 41°, 42°, 43°, 45°, 45°, 45°, and
46°. Some of them are twinned. The grains vary in size, and are
irregular in shape. The phenocrysts, lath-shaped sections, and
grains, or the two former only, occur sometimes together in the
same thin section, so that we have two generations of augite.
Lath-shaped sections and grains occur together, but most often the
grains occur alone.
6. Felspar.
The felspar, which is triclinic, occurs in two generations. Of the
fifty-nine largest crystals measured, one is over 3 mm. in length,
ten are over 2 mm., seventeen are over 1 mm., twenty are ovor 5,
Digitized by Google
Vol. 50.] STRUCTURE OF CARBONIFEROUS DOLERITES AND TUFFS. 623
nine under 5 mm. Somo of these are broken and corroded, and
some hare zonal structure. They belong to the first generation,
and give lath-shaped or tabular sections. The majority of the smaller
felspars give lath-shaped sections. They are often twinnod on the
albite plan. I have measured a large number of extinction-angles
of adjacent lamellae, and have obtained about fifty in which the
extinctions take place symmetrically with reference to the trace
of the plane separating the lamellae. These sections are out of the
zone perpendicular to the brachypinacoid (010). The felspars
occurring in the ophitic augite collected from seven localities give
the following angles of extinction for adjacent lamellae : —
10° . 10° . 13° . 13° . 20° . 20° . 25° . 27° . 25° . 27° . 23° . 27° . 3o° . 32°
10° . 11° . 13° . 17° . 20° . 22° . 25° . 28 J . 30°". 2U° . 30° . 33° . 35° . '37°
All, except the first four, may be referred to labradorite or perhaps
to anorthite, and the two last to a plagioclase intermediate between
labradorite and anorthite. According to this test, therefore, the
majority of tho felspars in the ophitic olivine-dolerites of Derbyshire
may be labradorite ; this agrees with the determinations of Schilling
for similar rocks of tho Harz, though in the Derbyshire rocks some
of the felspars are probably bytownite. In a lath-shaped section
one individual extinguishes at an angle of 32°, and the other has
zonal structure, the outer portion extinguishing at an angle of 35°,
the inner at an angle of 45°, and the intermediate portions at
angles between 35° and 45°. This may be roferred to anorthite.
In the rocks with granular augite, from 16 slides I have obtained
26 cases of symmetrical extinction. In 22 of them the extinction- •
angle between two adjacent lamellae varies from 42° up to 61°.
The maximum for labradorite is 62° 30'. Three others give angles
of 63°, 68°, and 70°, and may be referred to bytownite or anorthite ;
and one gives an angle of 75° or extinctions referred to the trace
of (010) the angles 35° and 37°, and may bo referred to anorthite.
Several cleavage-flakes from a specimen near Tideswell Dale Quarry
(outcrop 17) in convergent light show an optic axis just outside the
field of view. They may be referred to bytownite. Theso results
confirm the view expressed by Teall 1 that the prevailing felspars in
the basic division of the normal plagioclase-rocks belong to the
labradorite-anorthite group.
7. Structure of the Lavas.
There are only eleven thin sections from eight outcrops which
contain no certain traces of olivine. These are from specimens of
rock which has suffered a certain amount of decomposition. In
fresher specimens from the same outcrops, olivine or it* pseudomorphs
are found. In only one of them, namely, outcrop 15, have I seen no
traces of olivine. The rock is much weathered, and I have little
doubt that a less altered specimen would be found to contain olivine-
1 « Britifh Petrography,' 1888, p. 147.
Digitized by Google
624 MB. H. H. ABN0LD-BEMRO8E OK TOTE MICROSCOPICAL [Nov. 1894,
pseudomorphs. Plagioclase occurs in every thin section examined.
Augite has been found in all the sections, except No. 30. In some
of them is the rhombic pyroxene, and in others are secondary
calcite, serpentine, and chloritic aggregates which probably have
replaced the augite. Magnetite or ilmenite occurs in nearly all the
sections. The rock consists essentially of olivine, augite, plagioclase,
and magnetite or ilmenite.
There are three main types of structure, olivine-dolerite, ophitic
olivine-dolerite, and oli vine-basalt.
The olivine-dolerite occurs most frequently. It consists of augite
in grains, olivine in idiomorphic crystals, plagioclase giving lath-
shaped and tabular sections, and magnetite or ilmenite in rods and
grains. The Tideswell Dale Rock figured in Teall's * British Petro-
graphy,' pi. ix. fig. 2, well illustrates this type, except that the
olivine is in many cases much less altered than in the figure. In
the least-altered specimens there is, as a rule, not a large amount
of interstitial matter. In outcrops 9, 56, 57 the groundmass some-
times consists of a small felt of felspar-laths often giving parallel
extinction, and similar to the microfelsitic base of the Tynemouth
dolerite figured by Teall.1
The ophitic olivine-dolerite consists of augite in ophitic plates
forming the groundmass, in which are embedded the idiomorphic
olivine, the plagioclase often giving large lath-shaped sections, and
magnetite or ilmenite. PI. x. in Teall's ' British Petrography ' illus-
trates this structure. The minerals in the least-altered specimens
of the Derbyshire rock are quite as well preserved as thoso in the
• Scottish Tertiary dolerites. This structure occurs only in out-
crops 4, 6, 7 6, 39, 44, 45, 60, and Black Hillock 105. In only
one of these, namely 39, have I found the granular augite, and
in no specimen both the ophitic and granular augite together —
if we except a few cases in which some granules of augite are
penetrated by one or more felspars. When the ophitic augite
occurB, it generally forms the wholo groundmass in all specimens
which have been collected from the outcrop.
The olivinc-basalt contains olivine and large augite-phenocrysts.
(In outcrop 14 the augite is often larger than the olivine, and
sometimes encloses a small crystal of it.) The phenocrysts of olivine
and augite lie in a groundmass of small felspar-laths, of augite in
small phenocrysts, grains, and prisms which give lath-shaped sections,
and of magnetite or ilmenite. There is little interstitial matter
present. The rock is in a very good state of preservation, all the
minerals being quite fresh, except that the olivine is sometimes
slightly altered along the cracks. The rock is a typical olivine-
basalt." A thin section containing augite-prisms and magnetite is
similar to one of the Dudley basalt figured in ( British Petrography/
pi. xxiv. fig. 2, except that the Derbyshire rock contains olivine. I
have found this basalt only in outcrops 14 and 19, and in each
case its specific gravity is greater than that of the olivine-dolerite
1 « British Petrography/ 1838, pi. xii.
Digitized by Google
Vol. 50.J STRUCTURE OF CARBONIFEROUS DOLERITBB AKD TUFF8. 625
with granular augite which makes up the remainder of the outcrops
(except the tuff underlying No. 19).
In some places and outcrops the rock is so much altered that it
might he called an olivine-diabase, or diabase-mandelstein. Even
in the same outcrop it may be a dolerite little altered in one place
and an olivine-diabase in another, while a further Btage of de-
composition results in a more or less granular, clayey material
containing spheroids of diabase. I hayo described it as an olivine-
dolerite in the Table (p. 608).
Part II. — The Fraombntal Rocks or Tuffs.
The tuffs cover a much more extensive area than had been pre-
viously supposed. Two outcrops, namely, those at Ashover and
at Hopton, are mentioned in the Geological Survey memoir. In
addition to these I have found eleven others. I am not aware that
any of them have been microscopically described, and for this
reason and because in most cases they have undergone so little alte-
ration a detailed description of them is here given. Speaking
generally, petrographers have not bestowed so much consideration
on the fragmental igneous rocks as they have on the massive ones.
In the field, it is sometimes difficult to distinguish a tuff from a
decomposed amygdaloidal dolerite. A method that I have found
very useful is to carry a small file for filing the edge of the specimen.
After it is thus prepared and wetted, it is easy with the aid of a
lens to make out the lapilli in a fragmental rock.
The tuffs occur in all parts of the district, north, south, east,
west, and centre, and may be divided into a northern group and a
southern group, like the lavas. The northern group includes out-
crops 1, 7 a, 8 6, 16, 18, 19, 34, and the southern outcrops 39, 46,
53, 54, 56, 58. In 19 and 39 the layers of tuff are succeeded
immediately by a lava-flow. In 7 a and 8 6 we have a lava-flow
and tuff-beds separated by bands of limestone. In 7 b the lava is
uppermost, while in 8 6 it is the lower bed.
Caitleton, Outcrop 1. — This is seen in a field behind Goose Hill
Hall, towards Speedwell Cavern. It is triangular in shape, and
forms a ridge about 80 feet in length. The outcrop is almost
entirely covered with grasB. The rock is of two kinds, ono soft and
loose in texture, made up of fragments : a tuff ; the other, probably
blocks in this tuff, of a light-grey colour, hard, and weathering very
much like limestone. "With the aid of a lens, small felspar-crystals
may be seen.
Two specimens of the compact rock were examined (sp. gr. 2 67
and 2*66). Largo calcite-pseudomorphs after olivine occur. They
often contain portions of the base with small magnetite-grains, and
in one case two felspar-laths. The felspar occurs in a few rhombic
sections, also in large and small lath-shaped sections, often ragged
or forked at the ends, and in skeleton-crystals. The laths generally
have parallel extinction, and the mineral is partly or wholly altered
Digitized by Google
626 MB. H. H. ABN0LI>-BB1IB08E ON THE MICBOSCOPICAL [Nov. 1894,
to calcite. The base is isotropic, and in polarized light structureless.
In ordinary light it is seen to be of a brown colour, with a felt
of crystallites. The crystallites are often curved, feather-like in
arrangement, and frequently sprout from the ends of a felspar-lath,
so that they may perhaps be referred to felspar.
A specimen of the fragmental rock (sp. gr. 2*50) consists of
lapilli, some of which have a white porcellaneous appearance. Under
the microscope are seen several lapilli of a rock similar to that last
described. Some small ones are a dense black, with a thin, light
yellow border; sometimes they contain a few felspar-laths. The
larger ones, which are black or dark brown, are cracked, the
cracks being filled with a light yellow material or with calcite.
In reflected light the brown portions look like a cream-coloured
porcelain, parts of which are dirty and tinged with brown (see
PI. XXV. lig. 3). In a lapillus one large pseudomorph of olivine
is present, and is composed of a yellow material and calcite. Some
portions of the former are dichroic, but the greater part has only a
faint action on polarized light. The pseudomorph is surrounded
by a thick coffee-brown border, with bands parallel to the boundary
of the olivine. The whole is embedded in the dense black matrix
of the lapillus, the brown and the black being part of the same
mass and containing a few felspars in lath-shaped sections, a felspar
often being embedded in both portions. Smaller similar olivine-
pscudomorphs occur in the thin section. The brown border and
black matrix appear very much like tachylyte. Altered augite
occurs in bmall crystals or prisms. There are few vesicles: the
larger of these are filled with calcite, the smaller with a yellow radio-
fibrous material.
Brook Bottom, Outcrop 7. — This is mapped by the Survey as
running across Water Lane, which leads from Brook Bottom to
Tideslow Bake. I could only find it in the lane, where it is a
dolerite exposed for about 90 yards, and in an adjoining field. In
Brook Bottom, a valley, there is a rock exposed for a distance of
about 50 feet and dipping 18° about 10° W. of S. It is bedded,
and readily breaks into thin laminae, parallel to the bedding. It
consists of lapilli in a calcite-cement. The upper portion of the
bed crops out about 130 yards north of Highfield House, and is
exposed on the left-hand side of the road.
The bed of dolerite is 30 or 40 feet above the horizon of this
tuff, the two being separated by beds of limestone. The tuff is about
20 feet thick. The horizontal section, sheet 70 of the Geological
Survey, passes near this place ; and another bed of toadstone should
be added to make the section complete.
The tuff is generally laminated, but some portions are more
compact and do not break up into laminae. A specimen of the
former (sp. gr. 2*64) consists of lapilli of a reddish colour, which,
as well as the amygdaloids in them, have a thin yellow border. A
large lapillus with very irregular outline occupies the greater
portion of the slide. It contains olivine in porphyritic crystals
Digitized by Go
Vol. 50.] STRUCTURE OP CARBONIFEROUS D0LRRITE3 AND TUFFS. 627
with a well-defined outline, and entirely altered to a network, or in
some cases an opaque mass of iron oxide. The felspar is altered, and
has only a feeble action on polarized light. It occurs in rhombic
sections, one of which has an acute angle of 55°, and in lath-shaped
sections which often contain portions of the base. The base is red
in reflected, and a dense black in transmitted light, and, when
magnified 200 diameters, some portions are seen to have a reddish
tinge. The colour is probably due to iron oxide. Some portions
of the base are structureless aud free from miuerals, and in other
places a few hair-like crystallites are present. About half of the
section of this lapillus consists of vesicles varying much in size ;
the larger ones especially are filled with calcite, which is fresh and
shows the usual cleavages. The walls between adjoining vesicles
are often very thin. Some vesicles are filled and others fringed
with a light yellow substance, which also forms a border to tho
lapilli. It is grey in polarized light, and has but little action on it.
The smaller lapilli are similar, and unbroken across tho vesicles,
being fully formed individuals, and not fragments of a compact
rock. The lapilli are cemented by crystalline calcite.
A specimen of the more compact rock (sp. gr. 2*70) consists of
lapilli varying in size from an inch downwards, of a dark-chocolate
or of a green colour, in a cement of calcite. Under the microscoie,
some lapilli are of a light-green colour, and isotropic, and contain
magnetite ; others are similar to those in the specimen previously
described. The olivine is altered to a light dirty-yollow material,
aud the cracks are filled with iron oxide. Tho outline is often
clearly defined by a thin border of lighter material nearly trans-
parent, and having hardly any action on polarized light. Tho base
in some lapilli is a very dark brown, almost black (see PI. XXIV.
fig. o), and in others a lighter brown, which, under a magnification
of 200 diameters, is resolved into a number of crystallites with
parallel extinction ; they have a very feeble action on polarized light ;
the remaining base is isotropic. Numerous vesicles are filled with
calcite, and ail the vesicles have a very delicate outline.
Another similar specimen (sp. gr. 2-b'O) contains groups of a
mineral in yellow grains. They are dichroic, with cleavage-cracks
parallel to their length. The greatest absorption is parallel to the
cracks, and the extinction is always parallel to them. This mineral
is probably a rhombic pyroxene. Many of tho lapilli are elongated
in one direction.
Two blocks embedded in the tuff" were examined microscopically.
One of sp. gr. 2-74 is very amygdaloidal (calcite). Olivino occurs
replaced by magnetite or ilraenite. There aro few felspars, none of
which are fresh ; some of them are altered to calcite. The base con-
sists of felspar-microlites and magnetite-grains, or a reddish-coloured
substance. The other block (sp. gr. 2*08) is a very fine-grained
rock, and much altered. It contains pseudoraorphs of serpentine
after olivine, felspar-microlites, and magnetite.
Litton, Outcrop 8. — This is mapped by the Geological Survey from
Q. J. G. S. No. 200. 2 x
Digitized by Google '
628 MB. H. H. AR50LD-BEMR0SE 02? THE MICROSCOPICAL [Xov. 1 894,
Tideswell Lane head across the top of Cressbrook Dale into the
valley, and up the other side near Peter's Rock. It may be traced
from near the lane head to the highest house in Litton, the ' Peep
o' Day,' where it crosses the road. It is a bedded rock, and the
layers vary very much in coarseness. Subangular blocks, some being
12 to 18 inches in length, are found in it, especially in the upper
layers. There are also small pieces of a dark-coloured limestone.
There are good exposures on the roadside, and in two gullies in the
village. Climbing down into Cressbrook Dale, near Peter's Rock,
we find an outcrop of what is probably the same bed. It consists
of slabs 0 or 8 inches thick, which can be split into lamina; of
about j inch in thickness, and which at first sight appear like a
fine-grained sandstone. This is no doubt what Farcy 1 described east
of Litton as toadstone "so perfectly stratified that lamina? almost thin
enough for house slates might be got in it." These slabs are accom-
panied by coarser laminae like those at ' Prep o' Day.' The bed
may be traced up the hill in the opposite direction to the dip.
Proceeding down the valley, we pass about 15 to 20 feet of
limestone and then come to a bed of dolcrite between 10 and 20
feet thick. It is vesicular, and decomposed at the base, amygdaloidal
and hard at the top, and compact towards the centre. It weathers
hard and rough, the harder portions standing out in lumps of the
size of a man's fist, and it breaks off into nodular pieces. In it are
a vein and several nodules of quartz. The Geological Survey maps
only one bed, but there are two, the lower one an olivine-dolerite,
succeeded by 15 or 20 feet of limestone with fossils ; and this in
turn is overlain by a tuff, whose laminae, varying in coarseness, denote
variations in the character of the outburst.
A specimen of coarse tuff (sp. gr. 2-49) from this locality consists
of lapilli in a cement of calcite. A lapillus contains olivine and
augite-crystals, and one felspar, all altered to calcite, in a black
base, containing vesicles filled with the same mineral. Others con-
tain a few skeleton-crystals, probably felspar in a brown isotropic
base, and others pseudomorphs of olivine in a dirty-brown base
having slight action on polarized light. The vesicles are filled with
calcite, or with a yellow, feebly double-refracting substance.
In a specimen from the exposure on the roadside at « Peep o'
Day' the lapilli are brown or grey, with green amygdaloids.
Under the microscope only one lapillus contains any crystals, and
those are pseudomorphs of olivine, felspars in very small lath-shaped
sections, and magnetite. Some lapilli are a mass of vesicles filled
with a material having radio-fibrous structure, and separated by thin
walls of a generally isotropic baso. These lapilli were originally
more cellular than those from any other locality.
A much more altered specimen (sp. gr. 2*42) consists of black
lapilli. A felspar-like mosaic, the pieces of which are too small
to test by convergent light, fills the vesicles and the spaces between
the lapilli. A specimen of the laminated tuff near Peter's Rock is
' ' General View of the Agriculture and Minerals of Derbyahire,' voL i. (181 1)
p. 278.
Digitized by Google
Vol. 50.] STRUCTURE OP CARBONIPBROU9 DO LB RITES AND TUPFS. 629
much more altered. The lapilli vary much in size, they are yellow
and brown in colour, often isotropic, but sometimes have a feeble
action ou polarized light. Some of them are entirely altered to
calcite, others have a border of the isotropic material or of iron
oxide, whilst the interior is composed of calcite. The vesicles arc
rilled with calcite or with a clear felspar-like mineral, or again with
a brown substance which gives a more or less regular cross in
parallel polarized light. There are pseudomorphs of olivine in a
lew lapilli.
Four of the included blocks have been examined microscopically.
Their specific gravity ranges from 2'72 to 2*49. They are very
similar one to the other, so that a general description will suffice.
The olivine is altered either to a brown, partly transparent and
partly opaque substance, or to a clear felspar-like mosaic, the
portions of which are not largo enough to test by convergent light.
The felspar occurs in small lath-shaped sections, which often have
parallel extinction, and are often arranged with their long axes
parallel to the sides of an oiivine-section. A porphyritic crystal of
felspar occurs which is very much corroded. The extinctions are 0
and 15° referred to the trace of the plane of composition ; like many
of the olivine-pseudomorphs, the crystal is surrounded by a darker
portion of the base, with few or no felspars. The base is sometimes
dark, and contains flakes, rods, or skeleton-crystals of magnetite.
In other cases the base is a brown glass, more or less cloudy.
The amygdaloids often have a ropy or knotted vermicular structure.
The ropy part is calcite, or the clear felspar-like material, or both
together ; the interior is calcite, or the felspar-like mosaic. Some-
times iron oxide fills a vesicle.
Dove Holes, Outcrop 12. — This is mapped as toadstone by the
Geological Survey, and well described in the Memoir as ** a crumbly
bed, pale grey with green specks, and contains pebbles of limestone,
one of which was seen as big as a man's fist." 1 It is doubtful
whether the rock is an igneous product. It is very much decomposed
and lies between two beds of limestone : I have, however, been able
to find a piece hard enough for a thin section. Under the microscope
there are no signs of altered felspars or of altered lapilli ; the rock
has, in fact, the appearance of a clay. Were it not for the presence
of rounded lumps of limestone similar to those at Ashover and in
other tuffs, I should class it as a clay. If a tuff, it is so much altered
that no sign of the original structure remains.
Monk's Dale, Oatcrop 16. — This rock is situated where the road
from Tideswell to Ilargatcwall crosses Monk's Bale. It is difficult to
find, the outcrop being small, and for the most part covered with
grass. In a field, near the footpath to Wormhill, may be found in
the soil rounded pieces of limestone and of a rock like limestone
containing a few small lapilli. An exposure, about a foot square,
on the road to Hargatewall, consists of coarse and fine tuff,
1 Geol. Suit. Mem., JJ. Derbyshire, 2nd ed. 1887. p. 21.
2x2
Digitized by Google
630 MR. H. H. A R50LD-BEM BOSE OK THE MICROSCOPICAL [Nov. 1 894,
containing limestone-pebbles. The limestone dips rapidly down tho
hill, and this rock disappears underneath it. I could not find the
tuff on the eastern side of the valley.
A specimen of the finer-grained rock (sp. gr. 2-66) is a grey,
compact rock, consisting of dark amygdaloidal lapilli in a limestone
or calcite-cement. The lapilli are small, and are sometimes sur-
rounded by a dusty border. Some contain felspars often untwinned,
which extinguish parallel with their length, are almost entirely fresh,
and are not seldom arranged with their long axes parallel. Others
contain a pseudomorph of olivine, which occupies nearly the
whole of a lapillus. The groundmass is light green in ordinary
light, and isotropic. Some lapilli contain only amygdaloids, which
are generally isotropic. (See PL XXV. fig. 2.)
Another specimen (sp. gr. 2-63) consists of green and yellow lapilli
larger than in the preceding, with dark green amygdaloids. Olivine
and felspar occur as in the previously described specimen, but the
felspars are partly altered. There are small grains of calcite, and a
yellow serpentinous substance, which may be altered augite. The
groundmass is clear yellow-green in ordinary light, with little
action on polarized light. Some parts are darker patches containing
magnetite-dust or globulites. The rock appears to have undergone
alteration. Some of the vesicles are filled with calcite, others with
the clear yellow material, which is black or dark green in a hand-
specimen. This material consists sometimes of fibres radially
arranged, and shows a black cross in polarized light ; in other
portions it possesses little structure, and has hardly any action on
polarized light. Some of the amygdaloids are bordered with a dark
material, which under a magnification of GOO diameters, is seen to
consist of globulites. The )>ortions in which they occur remain
extinct between crossed nicols. Circular patches of globulites, or
curaulites, also occur in the groundmass. The cement is a very light-
brown substance, and is composed of small granules ( x b'OO diam.),
in which pieces of calcite and also {Kibbles of a more transparent
rock containing organisms are embedded. The cement of the first-
described specimen is similar, but contains no organisms. (See
PI. XXV. fig. 1.)
llavensdale Cottage (in Cresshrooh Dale), Outcrop 18. — It is ox-
posed in a small cutting in the side of the hill, on the left of the
path, in sight of the cottages, and near the gate leading into a
field. The rock is very much decomposed, traversed by numerous
veins oi* calcite, and contains small pieces of limchtone. It consists
of red lapilli in a brown cement. Under the microscope the lapilli
are of a dirty-brown colour, and often altered to a brown calcite, or
to clear calcite with a border of iron oxide. Some of the smaller
lapilli are yellow, and have a feeble action on polarized light : they
contain no crystals. There are some vesicles filled with calcite.
The cement is a dirty calcite. The rock is a much altered tuff,
mainly composed of what were probably glassy lapilli (sp. gr. 2 4^).
Digitized by Google
Vol. 50.] STRUCTURE OP CARBONIFEROUS DOLERITES AND TUFFS. 631
Miller's Dale Station, Outcrop 19. — This bed is mapped as run-
ning from Cressbrook through Taddington and Chelmorton to Great
Low. The rock is generally an olivine-dolerite, and in places an
olivine-basalt East of Miller's Dale Station a cutting has lately
been made for a tram-liue, which runs from the down line of rail-
wuy past the bottom of several large limekilns to the large lime-
stone-quarry abovo the toadstone.
The junction of the two rocks is well exposed. Resting on the
limestone are about 1 or 2 feet of a clay and a decomposed rock :
above this the rock becomes hard and breaks readily into lamina?.
It then becomes harder and less platy, and is altogether about
2 feet thick. It is very fine-grained and of a drab colour. Ex-
amined under the microscope, it is seen to be a crystalline limestone
with few, if any, organisms, and containing small lapilli. These
are often clear and glassy (isotropic), with globulites and sometimes
a felspar having parallel extinction. Sometimes they are brown, and
contain hair-like crystallites, the whole being isotropic. Some are
bordered with iron oxide. A few fragments of felspar showing
a biaxial figure, and pieces of caleite twinned like a felspar,
probably pseudomorphs, occur in the limestone. These are in a
specimen 6 inches above the clay (sp. gr. 2-46).
A specimen 9 inches above the clay (sp. gr. 2-52) is similar,
except that the lapilli are smaller, form a smaller proportion of the
whole mass of the rock, and are often altered to caleite.
A block of amygdaloidal rock (sp. gr. 2 02) embedded in this
ashy limestone contains pseudomorphs of olivine, large and small
felspar-laths, skeleton-crystals and rhombic sections of felspar in a
dark base, which is partly isotropic. Above the ashy limestone wo
find a large, irregular-shaped mass of hard, grey, amygdaloidal rock
several feet in thickness (sp. gr. 2*58), similar to the bloek previously
described, many of the felspars in it having parallel extinction ;
there is also a felt of crystallites with magnetite-skeletons in the
partly glassy base. About 9 feet above the clay this rock appears
more like an ordinary dolerite, and under the microscope the felspars
are seen to be larger, more numerous, and much less altered, and
there is a less amount of base.
Above this dolerite is a bedded coarse-grained tuff, the lapilli being
dark, with amygdaloids of caleite. Under the microscope the lapilli
may be divided into two kinds : (a) pseudomorphs of caleite after
olivine, felspar-laths mostly altered to caleite, and patches of caleite
in a dark groundmass coloured with iron oxide ; (6) yellow lapilli,
having little action on polarized light, and sometimes bordered with
iron oxide, some containing no crystals, and others felspar-laths.
The cement often consists of the same yellow substance with mag-
netite-dust. The limekilns, and the roads to them, are between the
coarse tuff and the spheroidal dolerite above it, so that the junction
is not seen.
Several hundred yards east of the kilns is another quarry in which
the ashy limestone and the dolerite abovo it may be seen ; both
are much more decomposed than in the exposure previously described.
Digitized by Google
632 MR. H. H. ARXOLD-REMROSE 05 THE MICROSCOPICAL [XoV. 1 894,
The upper dolerite may be traced for several miles. I cannot say
whether this tuff is merely local or underlies the upper dolerite
throughout its extent, as I have been unable to visit tho district
since I found the tuff.
We have here, resting on the ordinary limestone of the district,
an ashy limestone, denoting a slight fall of volcanic ash during the
deposition of the limestone. This is followed by a lava-tlow, that
again by a shower of coarse ash, and the whole by a lava-How, which
extends over a large area.
Cracknoivl Hoiute, Bakewell, Outcrop 34. — There is no good
exposure. In the valley below Cracknowl House, small patches of
red soil are seen on, the eastern side. They contain small lumps
of the rock, many of which would not be seen except for the
rabbit-burrows. The rock is much decomposed: the lapilli are
very much sltered and of a red colour, containing here and there
a much altered felspar-lnth and iron oxide. An included block
(sp. gr. 2'44) contains olivine replaced by a mineral which gives
aggregate polarization, probably felspar or quartz, and felspar-laths
of two generations, the smaller ones being often curved, bifurcated
and ragged, and frequently giving parallel extinction. Tho ground-
mass has a slight action on polarized light. Quartz sometimes tills
the vesicles.
Ember Lane, Outcrop 39. — Starting at the Bonsall end of Ember
Lane, we meet with the tuff on the left-hand side soon after the
turn from N.E. to E. It is exposed for about 200 yards in the bank,
and in a field on the left. It might at a little distance be taken for an
ordinary limestone, but, on closer examination, is found to be a lime-
stone with large lapilli embedded in it, which stand out in relief
when the rock is . weathered. Specimens abound in the walls.
Proceeding up the lane it passes into a bedded ash, which is seen
to contain pebbles of limestone just before we reach a small shed. It
is difficult to make out the bedding, but if the dip corresponds with
those of the limestone taken at Cromford, and between that place and
this locality, the ash lies above the ashy limestone, and is succeeded by
a dolerite-flow seen near and beyond the shed. It is vesicular, and
the olivine and felspars are much altered. If these conclusions as to
the dip are correct, we have here liraestono containing many lapilli,
or an ashy limestone, passing upwards into a bedded ash, and this
succeeded by a lava-flow. This dolerite covers a large surface on
Masson Hill, and is an olivine-dolerito containing in places augite
in grains, and in other places augite in ophitic plates.
Mapping tho toadstone from the 1-inch map on to the 6-inch
(which is not a very accurate method, as some of the details must
inevitably be exaggerated on the former scalo), it will be found that
the toadstone-outcrop passes through places where the dolerite and
ash occur, but not through those where the ashy limestone occurs.
The latter is on an inlier (assuming the dip previously mentioned
to have been correct) of limestone between the 700 and 900-feet
Digitized by Google
Vol. 50.] STRUCTURE OP CARBONIFEROUS DOLE RITES AJTD TUFFS. 633
contour-lines. On another small inlier of limestone, between the
900 and 1000-feet. eontour-lines near Low Farm, I found in the
walls pieces of a similar ashy limestone. I have been unable at
present to look carefully for any outcrop.
At Jughole Wood the dip is northerly ; between there and Low
Farm it in north-easterly. It is likely that the anticlinal seen in the
Derweut Valley, opposite the High Tor, passes near Low Farm. If
this he so, there may be two outcrops of limestone- tuff forming parts
of the same bed under the dolerite, and we should not expect to find
any signs of this bed of tuff in other parts of the outcrop of toadstone,
because they consist only of the upper part of the bed.
A specimen of the ashy limestone (sp. gr. 2*57) contains also
pebbles or pieces of limestone. Examined under the microscope, it
consists of lapilli in a limestone containing organisms. A large
lapillus contains olivine (altered to a green-and-yellow dichroic
material) and felspars with nearly parallel extinction, in a dusty
brown base. Others contain vesicles filled with a substance
having fibro-radial structure, lighter in colour than the remaining
parts of the lapilli, which are mostly isotropic. Sometimes the
outer portions of the lapilli are clear yellow and isotropic, the inner
portions being crowded with black enclosures and giving bright
colours in polarized light; in some cases they are fibrous, the
fibres being in bundles. Many amygdaloids occur, showing the
black cross as the nicols are rotated. Some vesicles are filled with
calcite, some with a black material, and others with the cement of
limestono. The lapilli are irregular in shape, and are often very
delicate in form. They appear to have fallen into a limestone in
process of formation, or into a limestone-paste.
Another specimen (sp. gr. 2-01) contains a largo lapillus about
1 inch in diameter. Olivine-pseudomorphs and felspar-laths occur in
a black base. There is a large quantity of crystalline calcite which
may be altered portions of the base, or which has more probably filled
in the numerous and large vesicles. Ofton half a dozen patches
which do not communicate have the same optical orientation,
extinguishing together, and contain parallel sets of cleavage-cracks.
In some parts the calcite is more plentiful than the black base, but
the latter is always a connected whole, the walls of the cells being
very narrow, except in a few cases where we have a smaller lapillus
in a vesicle of the large piece. Other lapilli are of a dirty brownish-
yellow colour, isotropic in parts, and in others having a roughly
spherulitic kind of structure. The oemcnt is a reddish-coloured
substance which contains small pieces of limestone with organisms
in them, and also probably small fragments of organisms. Here
the lapilli are mixed with fragments of already formed limestone,
and do not appear to be embedded in a limestone-paste as those in
the previously described specimen.
Grange Mill, Outcrop 46. — This is well exposed near the junction
of the roads to Winstcr and Ible, beyond the top of the Via Gellia.
The exposure is for some 15 yards on the roadside, and may be
traced in the fields on the right for about 100 yards.
Digitized by Google
634 MB. H. H. ARNOLD- B KM ROSE 05 THB MICROSCOPICAL [XoV. 1 894,
Opposite the Mill the structure is distinctly spheroidal. Fa rev says
that it has a ** boily and nodnlar texture " 1 here and near Hakewell.
At the latter place the rock is a dolerite, but here it is a tuff.
The spheroids van' from 2 feet down to 1 inch in diameter.
Some of the larger ones have several coats or shells, and others
arc divided into three or four pieces by irregular joints. At
first sight the rock might easily be taken for a basalt, but a closer
examination shows the spheroids to be composed of a grey rock
with green spots, which under the lens are seen to be amygdaloidal
lapilli. Prof. Bonney mentions a similar instance of spheroidal
structure in a volcanic ash in the Italian Tyrol, which at a short
distance might readily be mistaken for a decomposing basalt.3 This
is the only occurrence that I have found of spheroidal tuff in the
county. There are spheroidal blocks in the tuff near Kniveton,
but these are very different (see outcrop f)6, p. G38).
Proceeding towards Winster the rock is more massive and often
laminated, contains pebbles of limestone, and also a small bed or
else a collection of blocks of dolerite.
Near Shothouse Spring there is at least 10 feet of tuff exposed.
The layers vary much in coarseness and thickness, and there is no
Hpheroidal structure. The spring issues from the junction of the
tuff and the limestone above it, flowing along the top of the tuff-
bed. The latter is almost impervious to water, and when a speci-
men is dried it is seen to be made up of decomposed lapilli. About
100 yards farther north is a liracstone-quarry. A bed in it thins
out from several feet in thickness, and consists of lumps of a reddish-
coloured limestone containing a few small lapilli.
In a specimen from opposite the Mill (sp. gr. 2-64), the rock
consists almost entirely of lapilli. They van- in size and shape,
and are very tender and delicate, often having several branches.
In reflected light the lapilli and vesicles appear to bo coated with
a porcolain-like grey material, which makes up the bulk of the
rock. In transmitted light a coffee-brown colour borders the larger
lapilli, coats the inside of some of the vesicles, and constitutes the
whole of the sraallor lapilli. It is isotropic, and when magnified 600
diameters is seen to contain small globulites and is often bordered
by a thin layer of an almost black colour, probably magnetite (see
PI. XXIV. fig. 6). The inner portions of the larger lapilli and the
vesicles consist of a light yellow material which has a feeble action
on polarized light. The structure is fibrous, and the fibres are often
in bundles, but it sometimes shows aggregate polarization, and is
often bordered by a band of globulites. The interior of some lapilli
consists of crystalline calcitc and serpentine. Felspar occurs very
seldom. There are only a few lath-shaped sections, seldom twinned,
and all (except one of them) extinguish parallel or nearly parallel
with their length. There is a very little calcite filling some of
tho space between the larger lapilli : the remainder of the space is
1 « Agriculture of Derbyshire, etc/ vol. i. (1811) p. 278.
1 • On Columnnr. Spheroidal, and Fissilo Structure,' Quart, Journ. Geol.
Soc. toI. xxxii. (1876; p. 140.
Digitized by Go
Vol. 50.] STRUCTURE OF CARBONIFEROUS DOLKRITES AND TUFFS. 635
occupied with smaller lapilli. In some other specimens there is a
felspar-like material here and there in the lapilli which is biaxial and
may be secondary albite, and the outer vesicles of a larger lapillus
sometimes contain smaller lapilli.
A section cut from one of the spheroids (sp. gr. 2*45) shows a
similar structure, the only difference being that the brown lapilli
arc not quite isotropic, and contain more skeleton-crystals of felspar
and crystallites. Another specimen consists of yellowish-green
lapilli, containing no crystals, and with a thin black border. The
vesicles are filled with calcite surrounded bv a black border, or
with the black material only. Under a high power they often
consist of masses of globulites, and while sometimes free from
colour are in other cases stained by iron oxide. A section from a
bed of fine tuff noar Shothouse Spring (sp. gr. 2*46) consists of small
lapilli in a cement of calcite. They are water-clear, yellow, brown,
or black with magnetite, and generally isotropic. Several of them
contain what may be possibly pseudoraorphs of olivine. The
amygdaloids consist of fibrous material radially arranged.
A specimen of the rock from the quarry (sp. gr. 2'66) consists
of a limestone containing amygdaloidal lapilli altered to calcite,
and bordered with iron oxide. The limestone contains haematite.
Of the dolerite, two specimens have been examined microscopically.
One (sp. gr. 2-78) contains pseudomorphs of serpentine after olivino,
fresh augite in small grains, and unaltered plagioclase. The other
is a similar rock but more decomposed, none of the minerals being
fresh (sp. gr. 2*61).
Jfopton, Outcrop 53.— This exposure is opposite Hopton Hall
grounds, on the road from Wirks worth to Carsington, where that
from Hopton Wood joins it. On a cursory examination the rock
might be taken for a brecciated limestone, due to the decomposition
of the calcite which forms the cementiug-material of the lapilli. It
is described by Farey 1 as a 1 brecciated toadstoue/ and in the Survey
Memoir as '* a very coarse brecciated ash, with beds of dolerite." 2
The fragments vary much in size, from 2 feet in length down to the
size of a pea and smaller. Some are more or less rounded, but the
majority are angular. Where the surface of the rock is weathered,
the larger angular pieces project and give it a rough appearance.
I havo been unable to find any trace of a dolerite sheet. Wherever
larger pieces of rock aro seen, they are found to be included blocks.
Sometimes a face of the rock extending for several yards will look
like a massive rock, but when broken into proves to be made up of
small fragments. The rock is exposed for about 200 yards along
the road to Hopton Wood, and the lower parts arc mado up of the
same material as the upper. The finer-grained parts in a hand-
specimen are seen to consist of a black fine-grained dolerite, with
felspars similar to those of the larger blocks, and of green lapilli.
A thin section from a piece of the dark rock, which measures
2] x 2x 2 inches (sp. gr. 2-08), contains olivino, augite, felspar, and
1 Op. jam cit. p. 278. 3 P. 24.
Digitized by Google
636 MR. H. H. AR50LD-BEMR0SE 05 THE MICROSCOPICAL [Nov. 1894,
magnetite. The olivine is entirely altered to cloudy calcite and
serpentine. The augite is in smallirregular prisms and iu porphy-
ritic crystals, and generally unaltered. The latter often contain
portions of glassy material, and are sometimes cracked ; groups of
two or four individuals and twins are frequent. The felspar,
unaltered, occurs in porphyritic crystals which often possess zonal
structure. The lath-shaped sections vary in size. Symmetrical
extinctions of twins on the albite plan give angles of - , !j'0.
The first may be referred to the anorthite group, and the two la>t
perhaps to the labrador- anorthite group. Many of the smaller ones
extinguish nearly parallel to their length. The groundmass is black
and nearly opaque, and contains magnetite in skeleton-crystals.
Another specimen (sp. gr. 2 59) consists of five or six pieces of
the black rock about | inch in diameter ; the space between them
is filled with small fragments of a light-green rock and vory little
calcite. Three sections were cut from this specimen. The first
consists mainly of one of the larger pieces of black rock. The
olivine is altered to calcite with serpeutine along the cracks ; the
largest crystal measures *85 x *5 millim., and they are all well
bounded. The augite is scarce, occurring in small grains, prisms, and
porphyritic crystals. The felspars vary from 1 millim. in length to
less than -04 millim. The ends are sometimes jagged, and sometimes
bounded by crystalline faces : portions of the groundmass are included
in these felspars. Symmetrical extinctions of a twin give the
angles They are often arranged in groups, and sometimes two
are parallel and nearly touching one another, or touch through
part of their length as if they had been pushed up to one another.
This has been noticed in lapilli by A. Penck,1 and their juxtaposition
is attributed by him to the sudden cooling of the glassy base. Some
of the small crystals are arranged in the form of a cross. The ground-
mass is a dense black in ordinary light, with the ends of felspars
terminating in fine splinters merged in it. The black mass contains
a few hair-like microlites, *001 millim. in breadth, which extinguish
parallel with their length. In another portion the groundmass is
lighter, and consists of a felt of the microlites. Irregularly-shaped
and elongated vesicles are filled with calcite. The boundary of the
piece towards the inner part of the slide is irregular, and may be
compared to the forms of bays and promontories on a map. The
felspars near the border are always wholly contained in it and do
not project from it, whilst on the edge of the slide, where it is broken
by grinding, the crystals are broken across. These appearances
denote, 1 think, that — before grinding — the piece was a complete
individual. It is bordered by calcite, in which are smaller portions
of the rock with black groundmass, also a few small felspar-
crystals and fragments of augite, and small pieces of a very light
dirty-brown rock containing felspar-crystals in a glassy base ; see
PI. XXV. fig. 4. The second section from the same specimeu
1 ' Studien iiber lockere rulkanUche Auswiirflinge,' ZeiUcbr. deutsch. geol.
GeaclUch. toL xxx. (1878) p. 97.
Digitized by Go
Vol. 50.] STRUCTURE OF CARBONIFEROUS D0LERITE8 A2TD TUFFS. 637
contains one piece of the rook with black base ; the pseudomorphs
of olivine and the augite and felspar contain more of the ground-
mass than in the first case. The numerous lapilli are of a light-
yellow colour, and so completely isotropic that they are indistin-
guishable from the black rock undor crossed nicols. Magnetite-dust
is scattered sparsely through them, and thoy contain small augite-
grains and prisms and felspar-laths, but no olivine or microlites.
Felspar and augite occur singly in the calcite-cement.
The third section consists of lapilli of the black rock with smaller
felspars and augite-prisms, and of yellowish-green and brown lapilli
in a cement of crystalline calcite. The latter contain one fresh
olivino-crystal and some larger ones, replaced in part by a fibrous
brown substance. Tho augite is in very small prisms and in small
porphyritic crystals. The felspars are numerous and vary in size,
often having jagged ends. They are frequently grouped, and in some
lapilli they are bordered with magnetite. The groundmass is in
most cases isotropic, in some cases a slight action on polarized light is
observed, and there are a few circular spots which show a moro or less
regular black cross under crossed nicols. These were probably vesicles
originally. Sometimes the groundmass is cracked, and the cracks are
filled with magnetite. They do not run through the crystals, except
in very few cases ; the same crack is continued on opposite sides of
a felspar-crystal, or when it touches the end turns off at an angle.
There is no perlitic structure. In some lapilli a certain amount of
alteration appears to have taken place, and some have a dirty
colour which is probably due to iron oxide.
Lapilli of another specimen are of a brown colour. In ordinary
light they are differentiated into a darker brown portion and into
a lighter dusty one : the lighter part often forms what look like
cracks in the brown part. In polarized light the whole is iso-
tropic.
Knivelon, Outcrop 54. — This is a small outcrop in an inlier of
Mountain Limestone, exposed near the corner of a field a short
distance from the footpath which runs from Lea Cottage to Tissiugton
Wood Farm. The exposure is about 6 feet deep and 10 feet in length.
The rock is hard, and has a rough bedding along which it breaks
more easily than in any other direction. It is evidently a fragmental
rock, and does not contain spheroidal blocks such as those of
outcrop 56 (seo p. 638).
A large portion of a slide (sp. gr. 2*51) is occupied by one
lapillus, which is like the first block described from outcrop 56. It
is exactly similar in microscopical structure. In one amygdaloid
the felspar-like mosaic consists of separate portions large enough
to show a biaxial figure in convergent polarized light. The slide
contains several other similar large lapilli, with a more altered base,
and the amygdaloids in them contain smaller lapilli. Some of tho
smaller lapilli in the remainder of the slide contain no crystals, and
are often altered to the felspar-like material. The cement is
calcite.
Digitized by Google
638 MR. H. H. ARX0LD-BEMR08E ON THE MICROSCOPICAL [Nov. 1 894.
Another specimen of tuff (sp. gr. 2-54) is made up of lapilli in
a cement of crystalline caicite. The lapilli are of two kinds : — («)
{Similar to the blocks in outcrop 56, and (b) light green, almotrt
isotropic, containing globulites, or composed of the felspar-like
material. The vesicles are filled with caicite.
A third specimen (sp. gr. 2*50) is similar to the preceding
except that it contains lapilli of a yellowish-green glass with
crowds of globulites and a few felspars giving lath-shaped sections.
The globulites are often arranged in the form of a felspar-lath or
of a rhombic section. The vesicles are filled with caicite or the
felspar-like material with radio-fibrous structure.
Kniveton, Outcrop 56. — Lies between Woodcavcs Farm and Lea
Hall in a large field containing a limestone-quarry, and through
which the brook runs in a southerly direction. The field forms the
eastern side of the valley, and on the steep slopes the rock may be
seen in several places. In the upper part of the bed it is soft and
easily broken, and contains small pieces of limestone. There are also
included blocks of a very hard light-coloured rock, which is studded
with calcitic and dark green amygdaloids, and in this hard rock
minute felspars may be seen with a lens when the rock is wetted.
In the steep right-hand bank of the stream is a good exposure 10 or
12 feet high, without vegetation. It is almost entirely made up of
blocks more or less rounded, varying in size from lu inches to about
1 inch in diameter. They appear like spheroids embedded in a line ash.
When extracted, the ash adheres to their outer surface. In places
the ash predominates, and when broken up is found to contain smaller
spheroids of the harder and compact araygdaloidal rock. The ash
is made up of small lapilli, the amygdaloids in which are well seen
when the rock is wetted. Twenty feet higher in the series the ash is
exposed, and contains smaller and fewer amygdaloidal blocks. The
whole exposure is about 30 feet thick.
A section from one of the included blocks (sp. gr. 2*72) contains
olivine, altered partly to caicite, and partly to a fel6par-like mosaic
often containing pyrites. The felspar occurs in rhombic and in
lath-shaped sections. Some have parallol extinction and some are
not twinned. I have been unable to obtain twins with symmetrical
extinction. Three give the angles 23° and 27°, 20° and 30°, 25°
and 50°, referred to the trace of the plane of composition. The
ends are often indented, and some of the felspars contain globulites.
There are also microlites, which extinguish parallel to or at a small
angle with their length. They are sometimes curved. The base is
a very feebly-refracting fclspathic substance, sometimes brown with
globulites or magnetite, arranged parallel to the sides of tho oliviue-
pseudomorphs. The amygdaloids are large, numerous, and close
together. The felspars near them are often arranged tangentially
to tho almost circular amygdaloid boundary, and where the wall is
very narrow it is almost entirely formed of one or two felspars ;
see PI. XXV. fig. 6. Caicite generally fills the vesicles, and some-
times has an outer zone of feebly double-refracting grey material
whose fibres aro roughly parallel to the radii of the zone.
Digitized by Google
Y*L 50.] STRUCTURE OP CARBONIFEROUS DOLERITES AXD TUFFS. 639
Another block (sp. gr. 2-48) contains similar minerals, but the
base is often a dense black, sometimes a dark grey, and isotropic.
The vesicles are filled with calcite or with the felspar-like mosaic, or
both. Some vesicles contain lapilli without crystals, which are altered
to a mosaic in the inside, and bordered by a brown material which
contains globulites, is almost isotropic, and in roflected light has a
dirty porcellanic appearance. At one edgo of the slide is a large
group of these lapilli in a felspar-mosaic, which is probably an
amygdaloid.
A section from another block (sp. gr. 2'59) consists of a similar
rock bounded by a calcite-cement, which contains small glassy
lapilli without crystals, some of them altered to calcite. These
lapilli are probably portions of the ash adhering to the block.
In another block (sp. gr. 2*70) the felspars sometimes appear to
resemble twins, but both parts invariably extinguish together and are
separated by a portion of the base containing globulites. The smaller
felspars are often arranged in bundles and plumo-like forms,
radiating from a point so as to form a small sector of a circle.
There is very little base, consisting mainly of globulites in glass
(isotropic).
In a thin section of tuff (sp. gr. 2*40) tho lapilli vary from a
colourless, through a yellow to brown or dark-brown glass. A few
have a slight action on polarized light. The vesicles are of the
samo glassy substance, and are often surrounded by a border of
globulites or iron oxide, or both. One lurge lapillus only contains a
few felspars in lath -shaped sections altered to calcite.
Another thin section (sp. gr. 2*44) contains lapilli, very irregular
in shape and amygdaloidal. In some cases they are a mass of
amygdaloids with narrow walls. There aro a few probable pseudo-
morphs of olivine, but no felspar. A lapillus has a black base con-
taining pale yellow vesicles with a darker yellow border ; they have
a bright action on polarized light and a radio-fibrous structure.
Other lapilli are of dusty dark-brown or yellow glass, and others
more like tachyly te, with sometimes a slight action on polarized light.
Some lapilli are altered in part to calcite, and in part to a tine
felspar-like mosaic. When entirely altered to calcite, the lapillus is
traversed by cracks which are filled with iron oxide. Calcite
forms the cement between the lapilli.
A third specimen (sp. gr. 2*40) contains lapilli with olivine
altered to calcite, and felspar in small lath- shaped sections, crowded
together and often in bundles, in a base partly black and partly
transparent and isotropic. Other lapilli aro of clear and transparent
glass, containing strings and rods of globulites or longulites. Some
are altered to a felspar-like material which has very feeble action
on polarized light.
Ashover, Outcrop 59. — This occurs in a small inlier of Mountain
Limestone which has been brought up by au auticlinal. Exposures
are best seen in two cuttings which have been made to lime-kilus
on the right of tho road from Milltowu to Ashover. The rock is less
weathered in the cutting nearer Milltown. In a small cave on the
Digitized by Google
640 MB. H. H. ABHOLD-BBMBOSB 05 THE MICROSCOPICAL [Nov. 1 894,
right the layers are well seen. Those forming the roof become
detached, and fall to the floor by their own weight. They are about
1 inch thick. In the roof is a somewhat rounded block, measuring
7x5x4 inches, of decomposed dolerite. The olivine is replaced
by iron oxide, arid the felspars are much altered. Under the micro-
scope no augite is seen, though it cannot be said that it was never
present. 1 also found a nearly spherical block, 0 inches in diameter,
of a similar dolerite containing amygdaloids. 3Jany limestone-
pebbles ore found in this tuff.
In the cutting near Ashover the thickness of the exposed beds is
about 10 feet. Xear Fall Mill a shaft was sunk 70 yards through
this rock.' The rock dips east under the limestone ; for about
2 yard* below the junction it is powdery, and passes into a more
or less luniinated rock traversed by numerous veins of calcite and
containing fragments of chert, limestone, and dolerite. It is purple
and green in colour. The rock is so decomposed that it is difficult
to obtain a good piece for a thin section.
A specimen (sp. gr. 2'49) consists of dirty-looking green lapilli
in a cement of calcite and grey material. Under the microscope
the lapilli are light and dark brown or very pale green, all isotropic.
Some contain pseudomorphs of olivine, often in groups ; few contain
felspar-laths with parallel extinction. The vesicles are generally
tilled with calcite.
Another specimen (sp. gr. 2*46) consists of green lapilli with
dark green amygdaloids in a rod cement. Under the microscope
the lapilli are very light green. They contain no crystals, with the
exception of two which have a few felspars. In plane-polari/.ed
light the groundmass gives a lively play of colours, and sometimes
black brushes opening out into rude hyperbolae, not unlike those
seen in a biaxial crystal in convergent light.
Some are elongated and have elongated vesicles, which are filled
with a material similar to that of which the lapilli are composed,
and show a black cross due to radial arrangement of fibres. The
lapilli are often bordered with a black substance, and some are
entirely black throughout. The cement consists of smaller lapilli,
often isotropic, with a little calcite.
A third specimen (sp. gr. 2 35) contains lapilli which vary greatly
in size. The majority are very small and fantastic in shape, contain
no crystals, and are generally isotropic. Some are altered to calcite,
except on the outside border. (See PI. XXV. fig. 6.)
The fantastic outlines of the lapilli show that they cannot have
been formed by the trituration of a compact lava. They are differ-
entiated from the substance of the solid rock in the dolerites and
basalts of the district by their preponderating glassy base more or
less altered, the presence in it of a large number of skeleton-crystals
and crystallites, and by their numerous amygdaloids. Their" form
and structure prove that they arc true volcanic ejectamenta, and not
the product of broken-up lava-streams. They vary in magnitude
from very small fragments up to about the size of a pea.
' Geol. Surrey Mem., JJ. Derbyshire, 2nded. 1887, p. 154.
Digitized by Google
Vol. 50.] STRUCTURE OF CARBONIFEROUS DOLERITE8 AND TUFP8. 641
The thin sections containing lapilli may be divided into two
classes, olivine-bcaring and olivine-free. (The olivine is seldom
fresh.) Augitc occurs in very few cases of the former (mostly in
outcrop 53) and in none of the latter.
The lapilli of the first class are composed of a glassy base with
the addition of either : —
(a) Olivine, augitc, and plagioclase ; or
(6) Olivine and plagioclase ; or
(c) Olivine, plagioclase, and crystallites ; or
(d) Olivine.
The second class are composed of : —
(<?) Plagioclase in a glassy base ; or
(/) Plagioclase and crystallites in a glassy base ; or
(g) Glass only.
They sometimes contain magnetite in addition to the above mineral.
In some outcrops we have only a, o, c, rf, or g, as (a d g\ etc.,
whilst in others we have such combinations as (a d g), (b f g\ or
(defg)- Felspar is the prevailing mineral in them, and augitc
occurs the least frequently. Those results differ from those obtained
by Penck 1 for the crystalline secretions in basalt-tuff. He classes
them into (1) Plagioclase and olivine ; (2) Augite, olivine, and
magnetite ; aud (3) Olivine and magnetite.
The cement is crystalline calcite, or a paste consisting of smaller
lapilli (and probably their decomposition-products), or a limestone
paste. There is a very small admixture of uon-volcanic material.
This is almost entirely represented by the more or less rounded
lumps or pebbles of limestoue, which sometimes contain fossils. In
outcrops 46 and 59 blocks of olivine-dolcrite are found in the tuff.
In the remaining outcrops, except in 16, 18, 30, and 54, 1 have found
blocks with a more or less glassy base belonging to the olivine-bcar-
ing class, and, like the lapilli of that class, they may be divided into
a, o, c, and d. In outcrop 56 the blocks have a roughly spheroidal
shape.
The specific gravity of the blocks is greater than that of the lapilli-
tuff in which they are embedded, and if we compare blocks and
lapilli-tuff of similar microscopical structure from different outcrops,
we shall notice that the specific gravity of the blocks is always greater
than that of the tuff, and that the blocks in their turn have a iower
specific gravity than the doleritos of tho district.
It is interesting to compare the Derbyshire tuffs with those of
Carboniferous age in the Firth of Forth Basin, described by Sir
Archibald Gcikic.a In the Scottish tuffs no microlites wero found
such as those which are present in some modern volcanic tuffs. In
Derbyshire crystals of augite and felspar are found in the crystalline
cement of some of the tuffs. In the Scottish rocks the lapilli consist
1 'Ueber Palagonit- und Baaalt-tuffe,' Zeitschr. deutsch. geol. Goad lech,
vol. xxxi. (1K79) p. 571.
a Trans. Roy. feoc. Edin. vol. xxix. (1880) pp. 513-516.
Digitized by Google
642 MR. H. H. ARKOLD-BEMEOSE ON THE MICROSCOPICAL [XoV. 1S94,
chiefly of rounded or subangular fragments of the lava of the district
in which the tuff lies, and many of them do not differ in any respec t
from the substance of the solid rock as seen in sheets or dykes at
the surface. The Derbyshire lapilli are seldom rounded or subungulur
fragments, but answer rather to those of palagonite from Kilmundy
Hill and other localities, and like them have no counterpart amongst
the lavas erupted at the surface.
EXPLANATION OF PLATE8 XXIV. & XXV.
[The figures are all photographed from the microscope in ordinary light.
The first four are magnified 40 diameters, and the last eight 50 diameters.]
Plate XXIV.
Fig. I. Peak Forest pseudomorph ufter olivine, Outcrop 4. Near the top
of the figure is a small nucleus of fresh olivine, surrounded by a feebly
double-refracting substance, of which the nebulous patches are al«»
composed. The pteudomorph along the cracks is yellow and slightly
dicuroie ; the portions showing cleavage are yellow for rays vibrating
parallel to the short axis of the polarizer, and green for rays at right
angles to that axis. Both portions polarise in bright colours, and
extinguish parallel with the length of the origiual olivine.
Fig- 2. Potluck pseudomorph after olivine, Outcrop (JO, with cleavage parallel
to its length, and showing the position of the cracks in the original
olivine. It is enclosed in opbitio augite. It is yellow for rays
perpendicular to the short axis of the polarizer, and orange-brown
for those purallel to that axis.
Fig. 3. Potluck pseudomorph after olivine, Outcrop fiO. The greater portion
is yellow, with traces of cleavage parallel to its length. It is dichroic,
and polarizes in colours of the first and second orders. Two smaller
portions on the left are cut parallel to the cleavage-planes and show
an acute bisectrix (negative) with a very small axial angle. To the
right are plagioclase-latbs in ophitic augite.
Fig. 4. Potluck pseudomorph after olivine, Outcrop 30. The double refraction
is strong, and the polarization-colours are similar to those of biotite.
It is green for ray« \ibrating parallel to the short aiis of the polarizer,
aud pale yellow for those at right angles to that axis. The cracks
are filled with iron oxide. Above and below it are two similar, but
smaller pseudomorpbs.
Fig. 5. Portion of a large lapillus from Brook Bottom tuff, Outcrop 7. In the
left-hand portion the felspars are broken across. They are embedded
in a dense black groundmass, which contains several amygdaloid* of
calcite.
Fig. C. Lapillus from Grange Mill tuff, Outcrop 46. The internal portion has
a slight action on polarized light. The border is of a coffee-brown
colour and contains globulites. Smaller lapilli make up the greater
portion of the rock immediately surrounding it.
Plate XXV.
Fig. 1. Tuff, Monk's Dale, Outcrop 10. On the right is part of a lapillus with
an isotropic base. On the left is a fragment of limestone containing
organisms.
Fig. 2. Tuft*, Monk's Dale, Outcrop 1«. Amygdaloid lapillus with an isotropic
bate. Some of the crystallites have no action on polarized light,
others have a slight aciion and extinguish parallel to their length.
Fig. 3. Lapillus from Ca*ilcton tuff, Outcrop 1, containing several felspars.
It is of a black colour and cracked. The cracks are filled with, and
the lapillus is bordered by a light yellow material, probably an
alteration-product. The cement is crystalline calcite.
Digitized by Google
Quart Journ Geol Soc . Vol. L . Pl. XXIV.
H. AfiVOLO- BEMROSfc. PHOTO MICTO OCMROSE 4 SONS. f»0.. CCILO
CARfcOWIFEROUS DOLERITES AND TUFFS,
DERBVSHIRE
Digitized by Google
1
Digitized by Google
Quart Journ Geol Spa. Vol. L. Pl. XXV.
H. ARNOLD- BEMROSE. PHOTO-MICRO 0 E M ROSE A SONS. LTD , COUO.
Carboniferous Tuffs.
Derbyshire.
Digitized by Google
Digitized by Google
Vol. 50.] BTBTJCTVRB OF CARB0K1FEB0U8 DOLER1TE8 AHD TUFFS. 643
Fig. 4. Augite entirely embedded in the oalcite-cement of the Hopton tuff,
Outcrop 53. It extinguishes at an angle of 2tt° with the crack* which
run parallel to its length. On either side of it are yellow lapilli
which contain felspars, and are isotropic.
Fig. 5. Ashorer tuff, Outcrop 59. The lapilli contain no crystals. The tuff
is fine-grained, and the cement consists of smaller lapilli with a little
calcite.
Fig. 6. Part of a spheroidal block in Kniveton tuff, Outcrop 50, showing three
adjacent amygdaloid* separated by thin walla consisting of felspar,
magnetite, and interstitial matter. In the narrowest portions the
felspars are arranged tangentially to the boundary of the wall.
Discussion.
Sir Archibald Grixie, in complimenting the Author on the
completion of a laborious and valuable piece of work, alluded to
some of the striking points of resemblance between the microscopic
structures of the Derbyshire volcanic rocks and thoso of the Car-
boniferous series in Central Scotland. It appeared to him, however,
that the petrography of the region would not be adequately under-
stood until the history of the volcanic phenomena had been investi-
gated in the field with far more minuteness than had yet been
attempted. Having recently for the first time visited the • toadstone '
area, ho was able fully to confirm the suspicion which ho had
long entertained, that the story of these volcanic rocks was far
more varied and interesting than had been supposed. He had often
wondered why none of the vents of discharge had been detected in
a region so deeply trenched with valleys as Derbyshire. But in the
course of a few days he succeeded in discovering at least six of these
vents. They are filled with coarse unstratified agglomerate, and
are sometimes traversed by dykes or veins of dolerite or basalt.
As admirable examples, he described two such vents at Grange Mill,
west of Matlock Bath, where they rise through the limestones and
are flanked with a band of finely-bedded tuff, which may mark the
material ejected from them. Vents are found from the extreme
north to the extremo south of the limostone area, and even traverse
the Yoredale rocks.
While many of the toadstones are true lava-streams which, cither
with or without fragmental accompaniments, were poured out over
the floor of the Carboniferous Limestone sea, ho felt tolerably certain
that some of them are intrusive sills. In internal structure they
present a close resemblance to the usual type of Carboniferous sill in
the basin of the Firth of Forth. At one locality near Peak Forest he
found that the limestone overlying one of these sheets is marmorized
near the contact. Again, in Tideswoll Dale, as was well known, a
band of clay underlying another similar rock has been made
columnar to a depth of t) feet.
In his rapid traverses of the ground, the speaker had the great
advantage of the intimate local knowledge of the Author of the
paper, who had kindly guided him to the sections which he specially
selected as most likely to throw light on the volcanic history of the
region. He had urged Mr. Arnold-Bemrose to take up with the same
Q. J. G. S. No. 200. 2 y
Digitized by Google
644 CARBONIFEBOUS DOLERTTBS AND TUFFS. [Nov. 1 894,
patient and exhaustive industry the field-relations of the rocks.
He felt that it would probably be feasible to establish two distinct
petrographic types among the dolerites or diabases, one characteristic
of the contemporaneous flows, the other of the sills ; and that not
improbably some distinction might be made out, between the frag-
mental material which consolidated in the vents, and that which was
discharged over the sea-bottom. There were probably many dis-
tinct volcanic platforms in the district, but to determine their
succession accurately it would be necessary to work out in detail
the stratigraphy of the Carboniferous Limestone. Obviously an ex-
ceedingly interesting chapter in the volcanic history of this country
was recorded in Derbyshire, and ho trusted that the Author, living
as he did in the county, would undertake to decipher it.
Mr. W. W. Watts congratulated the Author both on the work he
had done and on the way in which he had presented it to the Society.
He thought that the perfect ophitic structure shown in some of the
sections would hardly be developed in a lava-stream, but only in a
sill. With regard to the identification of iddingsite, he had found
at least two varieties of brown pseudomorphs of olivine in similar
rocks, some of which were uniaxial while others were biaxial.
Br. Johnston-La. vis complimented the Author on working out so
thoroughly not only the massive rocks, but also the tuffs, which were
frequently neglected. Ho attributed the absence of olivine either to
the circumstance that the mineral has not individualized, or to the
facility with which it cracks and breaks up by a change of tem-
perature, so that the fine fragments might be easily overlooked in
old altered rocks like these. He would like to know whether the
calcareo-igneouB breccia was near the bottom of the deposits, as it
would most likely occur at the first explosive disruption at the
initiation of another cone. At any rate, he should expect it to be
associated with pumice, and he thought that one specimen shown
by the Author was undoubtedly an old altered pumice.
The Attthob thanked the speakers for the manner in which
they had received the paper. The interesting way in which Sir
Archibald Geikie had dealt with the subject would certainly induce
him to continue the work. In answer to Mr. Watts, the Teak Forest
rock referred to by Sir A. Geikie is an ophitic dolerite. In reply to
Dr. Johnston-Lavis, in one place at least, namely, in Ember Lane,
the tuff is more calcareous at the bottom of the exposed part of the
deposit than at the top. He did not think that the pseudomorph
of olivine was a surrounding of olivine by mica, as the alteration
proceeded along the cracks until the whole of the olivine was
replaced.
Digitized by Google
Vol . 50.] BANDED STRUCTURE OF SOME TERTIARY OADBR08. 645
40. On the Banded Structure of some Tertiary Gabbros in the
Isle of Skte. By Sir Archibald Geikie, D.Sc, LL.D., F.B.S.,
F.G.8., and J. J. H. Teall, Esq., M. A., F.R.S., Sec. G.S. (Read
June 6th, 1894.)
[Platks XXVI.-XXVIII.]
OoPfTENTS.
Pago
Introduction 645
I. General Arrangement and External Characters of the Books 646
II. Microscopical and Chemical Characters of the Bocks 650
III. General Deductions 055
(i) As regards the Conditions of the Protrusion of Igneous Magmas ;
(ii) As regards the Structure and Origin of Ancient Gneisses.
Introduction.
The dark basic rocks which stand out so prominently in the
geological structure and scenery of the Inner Hebrides have long
attracted notice and have been the subject of frequent description.
The writings of Macculloch,1 Von Oeynhausen and Von Dechen,'*
and J. D. Forbes3 in the earlier half of this century, and of
Prof. Zirkel4 and Prof. Judd5 in the later half, have made geologists
familiar with the general character and distribution of the Tertiary
gabbros. There is one feature, however, in these interesting masses
which has hardly received as yet the attention which it deserves.
We refer to the frequent bedding and banding which they present.
Even from a distance this structure may be distinctly recognized on
many of the great declivities. The northern hills of Hum, for
instance, can be readily seen to be built up of successive sheets, and
on the flanks of the Cuillin Hills in Skye a similar structure may be
observed. Macculloch has referred to what he calls the u obscurely
bedded disposition " of some of these rocks, and Prof. Judd has
stated that " the great masses of gabbro in Bum exhibit that pseudo-
stratification so often observed in igneous rocks." One of the
authors of the present paper has drawn particular attention to this
structure as evincing that the gabbro masses are not simple eruptive
bosses, but are composed of many sills and sheets, the result of
successive protrusions of material.6 He has also dwelt on the fact
that not only do these masses exhibit a bedded arrangement of
their materials, but that their individual beds sometimes display a
1 4 Western Islands,' 1819, toI. i.
a Karsten's Arcbiv, vol. i. p. 99.
3 Edinburgh New Phil. Journ. vol. xl. (1846) p. 85.
* ' Geologische Skizzen von der Westkiiste Schottlands,' Zeitechr. deutsoh.
geol. Gesellsch. vol. xxiii. (1871).
s Quart. Journ. Geol. Soc. vols. xxx. (1874) p. 220 ; xli. (1886) p. 354 ; xlii.
(1886) p. 49. See also the memoir by A. Geikie in Trans. Boy. Soc. Edin.
vol. xxxv. pt. i. (1888) p. 21.
• A. Geikie, Trans. Roy. Soc. Edin. vol. xxxv. pt. i. (1888) pp. 124-143.
Digitized by Google
646 SIR A. OEIKIE AND MB. J. J. H. TEA LL ON THE [Nov. I 894,
remarkable arrangement of the component minerals in separate
layers, which in their alternation and occasional puckerings recall
in a striking way the characters of many ancient gneisses.1
We propose on the present occasion to offer a more detailed
account than has yet been given of this banded structure among the
Tertiary gabbros. The investigation appears to us to have a two-
fold interest. In the first place, the structure in question occurs
among the deep-seated bosses of the latest volcanic series in Britain.
These bosses have undergone no deformation or sensible disturbance
since their production. The structures which they present may
therefore be accepted as belonging to the original conditions of
igneous eruption, and hence a careful study of the nature of this
remarkable banded separation of their component minerals may
throw somo light on the processes concerned in the protrusion and
consolidation of igneous magmas.
In the second place, this structure is so closely parallel to that
found in some of our oldest gneisses that there can be little doubt
that if its nature and origin can be explained, a distinct step will be
gained in the interpretation of the history of these ancient rocks.
We shall restrict our description to one locality in Skye — the
rugged ridge which strikes from the southern side of Harta Corry
and extends between Strath na Creitheach and Coire Riabhach to
Loch an Athain. This ridge has no name on the Ordnance six- inch
map, and we have been unable to ascertain how it is distinguished
by the inhabitants of the district. But the south-eastern part, which
is crossed by the tourist footpath to Loch Coruisk, is marked 1 Druim
an Eidhne ' on the map, and to avoid periphrasis we shall include
under this appellation the whole ridge up to tho crest overlooking
Harta Corry.
I. General Arrangement and External Characters
or the Rocks.
The ridge which we now describe forms a part of the gabbro
mass of the Cuillin Hills. This great region of basic rocks, evon if
we exclude Blaven and the eastern offshoots, covers an area of some
30 square miles. But as the gabbro can be traced continuously
into Blaven, save for the brief interruption of the alluvium of Strath
na Creitheach, the total area of this rock is probably not less than
40 square miles. It has been invaded by the granophyrc of the
Red Hills, which, sending a broad tongue into it as far south as
Loch an Athain, separates the Blaven hills from the rest of the
Cuillin group. Druim an Eidhne lies on the south-western side of this
invading tongue of ucid rock. But although in one sense the rocks
of this ridge lie at the very edge of the gabbro mass, yet, if we
disregard the presence of the younger granophyre, we see that they
really belong to the central portion of the gabbro.2 Hence, in
1 A Geikie, op. tit. p. 131 ; Rep. British Ajboc. (Nottingham) 1893, pp. 754-
766.
8 The evidence for the younger age of the granophyre has been ful for-
given from the name locality in thin Journal, May 1894, vol. 1. pp. 212-231.
Digitized by Google
Vol. 50.] BAWDED STRUCTURE OP 80ME TERTIARY OAR BROS. 647
discussing the various structures presented by the rocks of this
locality, we are brought face to face, not with marginal phenomena
of protrusion, but with the conditions under which the igneous
material was forced upward and consolidated in the deeper parts of
a great vent or duct.
No better example could be cited of the remarkably complex
nature of the great gabbro areas of the Inner Hebrides than is
furnished by Druim an Eidhne. This ridge, though forming part
of the central portion of one of these areas, does not consist of
merely one type of rock, belonging to one period of extrusion. It
is made up mainly of parallel beds, sills, or sheets, disposed in a
general N.N.W. direction with a prevalent easterly dip. These,
though presenting considerable differences in texture, minute
structure, and composition, may be classed under the common
designation of 4 gabbro.' Along their eastern edge a considerable
mass of coarse agglomerate may mark the position of one of the
older vents which served as passages for the uprise of the basic
eruptive rocks.
Four distinct varieties of material may be recognized among the
beds : (1) dark, fine-grained, granulitic gabbros which resemble
externally basalt-rocks; (2) well-banded gabbros, composed of
irregularly alternating bands and laminae of the several constituent
minerals ; (tf ) coarse massive gabbros destitute of any banding ;
and (4) pale felspathic veins.
The sequence of these varieties can to a certain extent bo
definitely established. It was not satisfactorily ascertained whether
the first-named series was anterior or posterior to the second. But
there can be no doubt that the coarse massive gabbros (3) have
sometimes been injected into both of them. It is equally certain
that the light-coloured veins are the latest of all, for they traverse
all the three other varieties.
1 . The, dark,fine-< trained Granulitic Gabbros. — These rocks play a
subordinate part in the structure of the ridge. In some parts they
weather with a smooth brown surface, on which their minute
reticulated veinings of epidote and calcite stand out prominently.
Below the outer skin a thin white crust may often be observed.
Occasionally small oval patches may be noticed, like half-effaced
amygdaloidal kernels.1 These external features of resemblance to
some of the altered conditions of the plateau-lavas are, however,
probably deceptive, for, as will be shown, the internal structure of
the rocks does not connect them with these lavas.
That these dark fine-grained sheets are older than much of the
rest of the gabbro of tho ridge is well shown by the way in which
the coarser varieties invade them and enclose lenticular patches and
blocks of them. But they run parallel with the banded sheets, and
though they might be presumed to be older than tho latter we were
nnable to obtain convincing proof of this relation.
1 Trans. Boy. Soc. Edin. vol. xxxv. pt. i. (1888) p. 169.
Digitized by Google
643 SIB A. GE1KIB AND MB. J. J. H. TBALL ON THE [NOV. 1894,
2. The Banded Gabbros. — It is in these rooks that the chief
interest of the series centres. Even from some distance their
remarkable structure is recognizable, owing to the striking contrasts
of colour which their weathered surfaces present. Parallel strips of
pale grey alternate with bars of dark brown, and, as the crags have
been intensely glaciated, the structure is revealed as distinctly as if
the rocks had been artificially cut and polished. The geologist who
is familiar with the aspect of the ice-worn hummocks of Lewisian
gneiss in the west of Sutherland, and who for the first time comes
upon these bare rocky knolls of Druim an Eidhne, may well be
pardoned if he for a moment should be inclined to insist that he
has before him another example of the same unmistakable outer
features and the same internal structures which characterize the most
venerable formation of the north-western Highlands. Nor is this
first impression immediately effaced by a closer examination. Not
until the whole mass of rock is considered and its relation to the
rest of the igneous masses is understood will the idea of an Archaean
age be definitely abandoned.
The banded gabbros occur in successive sheets or sills which vary
from a few feet to many yards in thickness. Indeed, their upper
and lower limits are not easily fixed, except when they are marked
by the intercalation of the dark, fine-grained sheets, or where they
are truncated by the massive gabbros. Each of these banded sheets
consists of many parallel layers of lighter and darker material,
which correspond in direct ion with the trend of the sheet itself, and
are usually inclined towards the east or south-east at angles ranging
from 20° to 30°. The component layers vary in thickness from
mere pasteboard-like laminae to beds a yard or more in thickness.
On a single exposed face of rock they may seem to be as parallel,
regular, and continuous as sedimentary deposits. But, as we trace
them along the strike, we observe that they are apt to vary in thick-
ness and even to die out. In this general parallelism and discon-
tinuity they present a strong resemblance to the arrangement of the
darker and lighter bands among the old banded gneisses.
In yet another particular the analogy with these ancient rocks is
sustained by the Tertiary gabbros. The parallelism of the bands
sometimes gives way to undulations or puckerings, and even to rapid
plications. A remarkable example of this structure is represented
in PI. XXVI., where a group of bands some 10 feet thick has been
doubly folded between parallel bands above and below.
Even before a minute examination of the banded structure is
made, the observer recognizes it to be due to an aggregation of the
several constituent minerals in distinct layers. The paler bands
are seen to be those wherein the felspar more especially pre-
dominates. The dark brown bands aro j>articularly rich in the
ferro-magnesian minerals and magnetite, which project from the
weathered surfaces as garnets do from the face of a crag of mica-
schist. The thin ribs of glistening black mark where the iron ore
is well developed.
A closer inspection reveals the fact that an intimate union exists
Digitized by Google
Vol. 50.J BANDED STRUCTURE OF SOME TERTIARY GABBROS. 049
between the materials of the successive bands. Instead of being
separated by any sharp line of demarcation, they are welded into
each other by the mutual penetration of their component minerals.
Thus the felspars of the pale bands project among the augites and
magnetites of the darker bands, while the latter in turn are
enclosed among the felspars.
No trace can be found here of any crushing and re-crystallization,
such as are familiar among the schistose rocks. The various
minerals, so far as can be judged by the eye, remain in their
original condition as they crystallized, savo with such alteration as
weathering may have effected in them. There are no * crush-
lines ' or * shear-planes,' nor any evidence of mechanical defor-
mation. Even the puckering and plication just referred to is not
attended with any sensible effect on the minerals.
In seeking among intrusive sheets of igneous rock for analogies
forms of what is known as flow-structure. Some of the gabbros of
the Inner Hebrides exhibit that structure in the most striking
manner. In the mountain Allival in tho Island of Bum, for
example, there lies near the base of the gabbros a sill of pale
troctolite, from 20 to 30 feet thick, in which the felspars are drawn
out parallel to the upper and under surfaces of the bed, in such a
manrier as to impart to the rock a lamination which might
cursorily be mistaken for that of some variety of schist.1 In the
banded gabbros of Druim an Eidhno, however, we havo not detected
any sensible lineation of the individual crystals in the direction of
banding. Whatever may have been the conditions under which
this banding was produced, they would therefore seem to have
differed in some measure from those in which ordinary flow-
structure was produced.
The occurrence of banded gabbros has already been described
from other regions, and further reference will be made to the
observations of previous authors in the second part of this paper.
But in these examples derived from rocks of great antiquity there
is often the difficulty of determining how far the banding has arisen
from some subsequent mechanical movement and re-crystallization.
The importance of the instances which we now cite from Skyo
appears to us to lie in the fact that they undoubtedly reveal original
structures.
No great terrestrial disturbances havo affected the region since
older Tertiary times, when the gabbros of the Western Isles were
extruded. We are thus enabled to study the direct results of the
protrusion and consolidation of igneous masses unencumbered with
any of the doubt and difficulty which often attend the investigation
of pre-Cambrian and even of Palaeozoic eruptions.
3. The Coarse Massive Gabbros. — These rocks, which form tho
familiar type of gabbro, have their minerals indefinitely aggregated
in a granitic texture. They are sometimes exceedingly coarse, with
with this banded
1 Trans. Roy. Soo. Edin. vol. xxzv. pt. i. (1888) p. 123.
Digitized by Google
650 S1K A. GKIKIE AND MR. J. J. H. TEALL 0» THE [Nov. 1 894,
crystals an inch or more in length. They occur as sheets, veins,
and more irregular masses, sometimes traversing and enclosing len-
ticles of fine-grained gran uli tic rock or cutting out parts of the
banding of the other gabbros. Their posteriority in such cases to
the two types of rock already described is thus made quite evident.
But where a bed of coarse massive gabbro lies between banded
sheets, with no visible evidence of transgression and no traceable
connexion with any mass which is transgressive, we are perhaps
hardly justified in shaking very positively as to its place in the
series of protrusions. All that can be definitely affirmed is that,
where the relative sequence of the rocks admits of determination,
the coarse massive forms are seen to have been protruded after the
first and second groups which have been here described.
4. The Pah Veins. — These rocks, from their abundance and
their conspicuous whiteness, aro prominent features all over Druim
an Eidhne, and indeed throughout the region of the Cuillin Hills.
They form irregular branching veins from several yards to less than
an inch in width, swelling out into thick aggregations and thinning
away into mere threads. Their whiteness is so much greater than
that of the pnle bands in the gabbros, as to show that they contain
a largo relative proportion of felspar with a smaller amount of
augite, olivine, and magnetite. That they belong to the gabbfos as
part of one complete series of protrusions is recognized in the field,
even before the microscope demonstrates t heir relation to those rocks.
Yet they cannot be regarded as mere 4 segregation-veins ' from the
rocks among which they rise. In the first place, the same vein may
be observed crossing successively examples of the dark hue-grained
sheets, the banded sheets, and the coarse massive gabbro. In the
next place, no sensible variation in com)>osition and structure can
be detected in these veins, as they strike from a rock rich in felspar
to one abounding in magnetite and the ferro-magnesian minerals.
They are undoubtedly intrusive where now visible, and, as they cross
all the other varieties of gubbro, they must be regarded as marking
the latest phase in the gabbro-protrusions of this locality.
II. Microscopical and Chemical Characters of the Rocks.
The Oranulitic Gahbros.—ln the fresh condition these are dark-
coloured, fine-grained, crystalline rocks composed of brown pyroxene,
water-clear felspar, green pseudomorphs, and magnetite.
the pyroxene occurs in grains of nearly equal dimensions in the
different directions (-1 to - miXVLmX \? is 8ometime8 {n the
T °*l'r*maV™^ but more frequently contains the inclu-
sions characteristic of diallage and pseudoihyperetheno.
i no grains of felspar resemble those of pyroxene in form and
size.
Ttrinninr, ;* ~ r- — « iuu*v ui pyroxene in form an
SL?on ^J^T?' bUt- the band* are few in number.
incLsionT f" ? 08 to a Vanet-V al,ied to labradorite. Minute
inclusions containing bubbles may be observed with a hiirh n Zr
The green pseudomorphs agree in form and size with ^he^grSna
Digitized by Google
Vol. 50.] BANDED STRUCTURE OP SOME TERTIARY GAB BROS.
651
of pyroxene : they are aggregates of minute prisms or fibres of
green hornblende, with which some chlorite is usually associated.
The prisms are not, as a rule, orientated in any definite direction,
bat cross each other in one and the same pseudomorph. Such
pseudomorphs are not uncommon in the coarser varieties of gabbro,
and they will be referred to in the following description as con-
sisting of pilitic hornblende. The magnetite occurs in smaller
individuals than the other constituents and occasionally shows traces
of crystalline form.
These rocks are remarkably uniform in composition (sp. gr. 3),
and their external resemblance to ordinary basalts has been already
referred to. Their typical granulitic structure, the absence of the
characteristic lath-shaped sections of felspar, and the frequent
occurrence of the diallagic modification of pyroxene are the features
which have led us to call them gabbros ; but it must be remembered
that they are sharply marked off from the rocks which remain to be
described by reason of the small size of the individual constituents.
The Banded Oabbros. — These are coarse-grained rocks composed
of pyroxene, plagioclase, olivine, and magnetite. Hornblende in
three forms, chlorite, and epidote occur as secondary or accessory
constituents.
The pyroxene is pale brown in colour, and, so far as our obser-
vations go, is in the condition of ordinary augite. The individuals
arc often elongated in the direction of the vertical axis, and cross-
sections occasionally show an approach to tho common eight-sided
form ; but the angles are always rounded. A tendency to ophitic
structure is not uncommon. Twinning of the ordinary type may
sometimes be observed. Grains of magnetite and pseudomorphs of
pilitic hornblende, similar to those already referred to in describing
tho granulitic gabbros, occur as inclusions. These pseudomorphs
may possibly represent olivine. The pyroxeno has not unfrequently
been partially replaced by uralitic hornblende, and in one caso this
change was seen to have taken place along cracks which could
be followed across the slide for a considerable distance. Where
these cracks traversed tho augite, the pale brown substance of that
mineral was replaced for a short distance on either side by green
uralitic hornblende.
Felspar occurs as grains, as irregular ophitic patches, and also in
forms which give broad rectangular sections; but these different
modes of occurrence are not as a rule found in one and the same
specimen. Twinning on the albite, pericline, and Carlsbad plans may
be observed. The perfection of crystalline form varies in different
rock-specimens. Where tho felspar is most abundant (PI. XXVIII.
fig. 1 ), there the idiomorphism is most pronounced, and where it is
least abundant (PI. XXVIII. fig. r>) it is moulded on the other
constituents and shows no trace of crystalline form. The extinction-
angles indicate a variety closely allied to labradorite. In a few
specimens the felspar has been rendered turbid by alteration, but
as a rule it is quite fresh and water-clear.
Digitized by Google
652 SIE A. GEDDE ASD MB. J. J. H. TEALL 05 THE [Nov. I 894,
Unaltered olivine has been recognized only in one specimen taken
from a black ultrabasic * schliere ' ; and although some of the
pseudomorphs of pilitic hornblende may represent this mineral in
other specimens, it is probable that it" did not play an important
part in the original constitution of the rocks. The" unaltered sub-
stance is nearly colourless in thin section, but the strings of magne-
tite and the yellow staining along cracks and at the edges of the
individual grains, described by Prof. Judd, are well developed.
The mineral is not idiomorphic ; but the other constituents have
been moulded on the rounded grains (PL XXV 111. figs. 5 & 6) in
such a way as to show that they must frequently be of later date.
No inclusions of augite in olivine have been observed.
Magnetite (titano-magnetite) is usually present, either in the
form of rounded grains or as large irregular masses. Cry stab are
rare. The mineral is found also, as we have already pointed out,
in the veins traversing the olivines : but this mode of occurrence is
quite distinct from that with which we are now more especially
concerned. There can be no doubt that magnetite entered largely
into the original composition of these rocks. The irregular masses
contain rounded grains of augite as inclusions, and these are some-
times so abundant that the magnetite is reduced to the condition
of thin strings separating the augite-grains (PL XXVUL fig. 4).
The analyses reveal the presence of titanic acid, and on this account
polished surfaces of a variety of rock composed of augite and mag-
netite were etched with hydrochloric acid, in order to ascertain
whether the iron ore was an intergrowth of magnetite and ilmenite.
No evidence of such intergrowth was obtained. A surface free from
cracks appeared to be uniformly attacked, and the solution contained
titanic acid.
Brown compact hornblende is very feebly represented in these
rocks. It has been observed only in a few "specimens, in the form
of small irregular patches in the augite. Green hornblende is
present, both in the fibrous or uralitic form and in the pilitic form.
Secondary hornblende and chlorite not only occur as pseudomorphs,
but also in narrow veins traversing the "other constituents. The
only other mineral which remains to be noticed is epidote. This
has been observed only in one or two of the slides ; it occurs as
irregular grains in the felspar.
The banding which forms so striking a feature of these gabbros is
due to a variation in the relative proportions of the four essential
constituents — labradorite, augite, olivine, and titano-magnetite.
The light-coloured bands are rich in felspar : the dark bands are rich
m the ferro-magnesian constituents and magnetite. Here and there
black * schliercn,' composed entirelv of augite and iron ore, occur.
The more basic portions are not limited to the margins of the masses
but alternate with the more felspathic portions to form the banded
complex. There is no essential difference between the different
bands as regards coarseness of grain, and the individual minerals
interlock with each other across a junction-line just as they do in
the central portion of a band. It seems impossible, therefore, to
Digitized by Google
Vol. 50.] BANDED STRUCTURE OF 80HK TERT1ART GAB BROS. 653
account for the banding on the supposition that magmas of varying
composition have been successively injected. The individual minerals
are optically perfect, and their mutual relations are such as occur in
igneous rocks. Cataclastic phenomena have not been observed in
any of the slides prepared from the banded series, and we therefore
conclude that the cause which produced the banding must have
operated before the crystallization of the minerals from an igneous
magma.
Some idea of the variability in composition of different layers
may be formed from the following analyses kindly made for us by
Mr. J. Hort Player in the Laboratory of the Survey at the Museum
II. III.
40-2 29-5
47 9-2
9-5 3-8
9-7 178
122 182
•4 -4
•4 3
131 10-0
8O 8-7
•8 -2
•2 1
•5 10
99-7 99-2
Sp.Gr 291 3-36 387
J. Hort Playeb, April 9tli, 1894.
I. (5373 l). A light-colourod band mainly composed of labradorite.
The other constituents are augite, uralitic hornblende, and
magnetite. (See PI. XXVIII. tig. 1.)
II. (5377). A dark band composed of augite, magnetite, and
labradorite. (See PI. XXVIII. fig. 3.)
III. (5370). A thin ultrabasic 4 schliere,' mainly composed of
augite and magnetite. (See PI. XXVIII. fig. 4.)
It is evident from those facts that rock-specimens varying greatly
in chemical and mineralogical oharacter may be obtained from the
banded gabbros of Druim an Eidhne. Some may bo termed normal
gabbros, others magnetitc-gabbros ; while others again consist of
magnetite and pyroxene, and may be called magnet ite-pyroxenites.
These last, however, so far as our observations go, are not developed
on any large scale.
Occurrences similar to these are known in many other localities
where gabbros, norites, and hyperitcs are developed on a large scale,
1 The numbers are those of the microscopic slides in the Collection of the
Geological Survey.
of Practical Geology, Jermyn Street : —
Analysis of I.
Silica 52-8
Titanio acid *5
Alumina 17*8
Ferric oxide 12
Ferrous oxide 4*8
Ferric sulphide
Oxide of manganese
Lime 12*9
Magnesia 4'8
Soda 3 0
Potash -5
Loss by ignition 1*2
99-5
Digitized by Google
654 SIB A. GEIkJE AND MB. J. J. H. TBALL 05 THE [Nov. 1 894,
especially in Scandinavia and North America.1 Here, as in most of
the other allied cases, the iron ores are titaniferous. The case
which comes nearest to the one under consideration is that described
by N. H. & H. V. Winchell in Bulletin VI. of the Geological Survey
of Minnesota, p. 126. Speaking of the gabbro of the Mesabi
Range, the authors say : — " Occasionally a gneissic (laminated)
structure is seen in it. Such occurs on the east shore of Birch
Lake where a conspicuous hill is marked by parallel weather-lines
sloping towards the south, the lines being due to the weathering-out
of the contained olivine, which is disseminated in alternating sheets
of greater and less prevalence throughout the hill. . . . This gneissic
structure is not due to shearing-pressure nor to sedimentation, but
to a varying abundance of the more easily decaying minerals, such
variation occurring in sheets, and on the weathered edges appearing
as depressed lines or grooves." The writings of other authors con-
tain references to gneissic structure in the gabbros and norites which
are associated with ore-deposits ; and Vogt figures such structures
in a dyke of ilmeuite-norite at Storgangen in Norway (Geol. Foren.
Forh. vol. xiii. 1801, p. 496).
The Coarse-grained Massive Gabbros. — The constituents of these
rocks are the same as those of the banded gabbros, except that olivine
has not been observed. The uralitization of the augite has often taken
place to a greater extent than in the members of the last group, and
with the change in the character of the ferro-magnesian constituents
is associated a change in the colour of the rocks. The normal
gabbros are brown or black ; the uralitized gabbros green. The
felspars in some of the uralitized gabbros show marked signs of
having been fractured and broken ; but this action has been local in
its character, and may possibly be connected with the molecular
changes in the augite. The rocks of this group are much more
uniform in composition than those of the banded scries. Neverthe-
less variations in the relative proportions of the different consti-
tuents do occur. The specific gravities of three specimens are
respectively 2-82, 2-97, and 3*06.
TJic later Gahbro-vnns. — These rocks are composed of the same
constituents as t hose of the last group ; but the felspar is, as a rule,
tar more abundant, so that they are lighter in colour. Inclusions of
the fine-grained granulitic gabbro occur in tho veins. Apatite,
which has not been noticed in the rocks of the other groups, is
easily recognizable in the veins. In the few specimens from which
microscopic sections have been prepared hornblende predominates
1 See A. Sjogren (Geol. Foren. F6rh. vol. iii. p. 42, I87*i. and rol. vi. p. 264,
1882); Tornebohm {ibid. vol. v. p. 610, 1881); Vogt (ibid. toL xiii. 1891);
Wadfeworth (Lithological Studies, Mem. Mus. Com p. Zool. Harvard, vol. xi.
1884) ; Winchell (Minnesota Geol. Surv. Bull. vi. 1891); Adam* (' Ueber das
Norian oder Ober-Laurentian,' Neues Jahrbuch, Beilage-Band viii. 1893). An
••re-deposit, consisting of magnetite and pyroxene associated with a peculiar
nepheline-pyroxene rock (jacupirangite), has been described by O. A. Derby,
Amer. Journ. »Sci. ser. 3. vol. xli. (1891) p. 311.
Digitized by Google
Vol. 50.] BANDED STRUCTURE OP 80ME TERTIARY GABBROS. 655
over the augite, and assumes in some cases a more compact character
than is the case in the other rocks. Taking the rocks of Draim an
Eidhne as a whole, the compact hornblende which forms so marked
a feature in the foliated gabbros of the Lizard is conspicuous by its
absence, and so also is the saussuritic modification of tho felspar.
The specific gravities of two specimens from tho veins were found
to be 2*78 and 2*85 respectively.
III. General Deductions.
From the facts which have been here described we may proceed
to indicate some of the conclusions which seem to us to be legiti-
mately deducible from them. There are two liues of enquiry on
which these facts may be made to throw some light. In the first
place we may enquire how far they serve to extend our knowledge
of the conditions under which igneous magmas may be protruded and
consolidated, and in the second place we may consider to what
extent the phenomena exhibited by these Tertiary gabbros serve to
elucidate the structure and origin of the oldest gneisses.
(i) We are accustomed to think of an igneous magma as fairly
uniform in its composition at the time of its intrusion into
surrounding rocks or extrusion at the surface ; and in the majority
of cases this view is probably correct, so far as the massive igneous
rocks are concerned. If samples equal in bulk to that of an average
hand-specimen could be taken from various portions of the molten
mass at the time of its rise to the place where the igneous rock is
now observed, they would probably be found to possess the same,
or very nearly the same, chemical composition. Crystals are no
doubt often present in the magma at the time of its intrusion or
extrusion, but they are usually distributed with approximate
uniformity through the still molten material, and do not, therefore,
affect the question we are now considering. As an illustration of
uniformity in the composition of one and the same mass of rock we
may refer to the Cleveland Dyke, which has been traced at intervals
for a distance of 90 miles across the North of England. It traverses
Jurassic, Triassic, and Carboniferous strata of the most diverse petro-
graphical characters without undergoing any marked change either
in composition or structure.1
Turning now to larger masses of rock which occur as sills, lacco-
lites, and bosses, we find that uniformity in composition is not so
marked a feature as it is in the majority of dykes.3 Such differences
as occur may, howover, in many cases be explained by differentiation
subsequent to intrusion— differentiation in situ as it may be termed —
1 4 Petrological Notes on some North-of-England Dykes,' by J. J. IT. Teall,
Quart. Journ. Geol. Soc. vol. xl. (18*4) p. 209.
a But dykes are not always uniform in composition. See A. Gcikie, ' The
Pitchstone of Eskdale,' Proc. Roy. Phys. Soc. Edin. ?ol. v. (1880) p. 219;
A. C. Lawson, 4 Petrographical Differentiation of certain Dvkes of the Rainy
Lake Region,' 4 American Geologist/ vol. vii. (1891) p. 153; Prof. J. W. Judd,
4 On Composite Dykes in Arran,' Quart. Journ. Geol. Soc. vol. xlix. (1893) p. MS/6.
Digitized by Google
*>56 SIR A. GKIKIE ASD MB. J. J. H. TEALL OK THE [Nov. 1 894,
and, so far as this is the case, they do not imply heterogeneity in
the magma at the time of intrusion.
Passing on to still larger areas, composed of typical plutonic rocks,
such as that of Garabal Hill and Meall Breac,1 we often find what
is evidently a connected series of intrusions exhibiting a wide range
in chemical and mineralogical composition, and certain definite,
though probably not very great, differences in age. Such a plutonic
area, taken as a whole, though forming a petrological complex, is a
geological unit. The complexity in such cases cannot wholly be
accounted for by differentiation in situ. The more abrupt changes ■
require the hypothesis of successive intrusions, which probably repre-
sent differentiation elsewhere of the same general character as that
which has taken place to a smaller extent in situ.
We recognize, therefore, two causes of petrological complexity in
plutonic areas of the same kind as those referred to by Prof. Judd
in his paper 'On Composite Dykes in Arran': (1) differentiation
in situ, and (2) successive intrusions. But the facts described in
this communication appear to point distinctly to yet another cause,
namely (3) the intrusion of a heterogeneous magma. That the
banding in the gabbros is not due to differentiation in situ is proved
by the fact that the succession of more basic and more acid material
bears no definite relation to the margins of the banded series, as is
the case with dykes of the Rainy Lake Region described by Prof.
Lawson.2 and with the Huk Dyke described by Prof. Vogt.3 And
even if we could suppose that some physical cause, acting independ-
ently of the margins, might determine a segregation into parallel
bands, we should still be unable to account for the folding described <
in the first part of this communication, which must have taken
place during intrusion and before consolidation. The hypothesis of
successive intrusions seems equally inapplicable, for, taking the
banded series as a whole, every intermediate type of rock between
the most basic and the most acid may be observed ; and where the
junctions between the dark and the light bands are fairly sharp, the
minerals, as we have already explained, interlock with each other
across the junction-line, just as they do in the interior of the bands.
These considerations have, therefore, led us to the conclusion that
the banding is the result of the intrusion of a heterogeneous magma.
We think that after reaching its present position, and before con-
solidation, the molten mass possessed those variations in composition
which are represented in Mr. Player's analyses (p. 653). According
to this view the heterogeneity must have been produced by causes
operating elsewhere, and probably at lower levels in the earth's
crust. We know nothing as to the original forms of the more or
less differentiated masses. Then came the intrusion of the hetero-
geneous magma as sills, and it was by the deformation of the molten
1 ■ On the Plutonic Rooks of Garabal Hill and Meall Breac.' by J. B,
Dakyns and J. J. H. Teall. Quart. Journ. G*ol. Soc. rol. xlnii. (1892) p. 104.
•. rol. vii. , 1S«>1 1 p.
mnelsen de vigtigrte Grupper Jernmalmforekomster,' Geol.
W**u. rVrh. vol. xm. (1891) p. 484.
Digitized by Google
Vol. 50.] BANDED STRUCTURE OF 80MB TERTIARY 0ABIIR08. 657
mass (luring intrusion that the handed structures were produced.
This is our hypothesis. We do not offer it as an original one, but
merely as that to which we have been led from a consideration of
the facts above described.
(ii) We pass on now to consider the extent to which the phe-
nomena exhibited by these Tertiary gabbros may serve to elucidate
the structure and origin of some of our oldest gneisses. The extra-
ordinary resemblance of these gabbros to the Norian (anorthosite)
rocks of the North American Continent was clearly recognized
by earlier observers. More detailed observation has served to
extend the points of resemblance. The deposits of titaniferous iron
ore and the gneissose structures of the Norian formation have their
analogues in the black masses, extremely rich in titano-magnetite,
and in the banded structures to which attention has been directed
in this paper. It seems impossible, therefore, to avoid the conclusion
that the cause, whatever it may have been, which produced the
phenomena in the one case operated in the other, and that the
pre-Cambrian anorthosite rocks of Canada originated under physical
conditions closely allied to, if not identical with, those which give
rise to the Tertiary gabbros of Skye.
It will be interesting, however, to compare these gabbros with
Archaean rocks nearer home. The Lewisian gneiss of the North-
west of Scotland is a petrographical complex, largely but not
entirely composed of gneisses having marked affinities with piutonic
igneous rocks. The area of this ancient formation already mapped
in detail by the Geological Survey forms a narrow border along the
coast, extending from Cape Wrath to Loch Torridon. In no portion
of this area do rocks of uniform character cover any large tract of
country, but extreme petrographical diversity may be said to
characterize the formation. Between Cape Wrath and Loch Laxford
hornblendic and micaceous gneisses predominate, and these are
often traversed by intrusive veins and sills of gneissose granite and
pegmatite. The area south of this district, extending from Scourie
to some distance beyond Loch Inver, is very largely composed of
augitic gneisses, with which banded rocks of ultrabasic composition
— peridotites, pyroxenites, and pyroxene-granulites — are associated.
Hornblendic and micaceous gneisses also occur. Another feature of
this area is the extraordinary abundance of basic dykes. South-
wards, in the neighbourhood of Gairloch and Loch Torridon, horn-
blendic and micaceous gneisses again predominate, and bands of
hornblende-schist, which appear to represent the dykes of what we
may refer to as the middle zone, are extremely numerous. In the
neighbourhood of Loch Maree limestone, garnetiferous mica-schists,
and graphite-schists occur. As these are probably metamorphosed
sediments, we need not further refer to them in the present com-
munication.
The petrographical changes are sometimes gradual and sometimes
abrupt. The mode of association of the different varieties, or the
architecture of the rock-masses, as Prof. Brogger would say, is
Digitized by Google
058 SIB A. GEIKTE AST) MB. J. J. H. TBAIX OS THE Nov. 1S94,
extremely diversified In some places no definite order of arrange-
ment can be made out ; in others we find veins of more acid material
penetrating masses of more basic material : and in others a kind of
breccia has been formed, in which lumps and fragments of basic rocks
lie in a matrix of acid rocks. Then, again, every possible kind of
parallel structure may be observed. In some cases this is only
faintly indicated in the arrangement of the minerals, or in the
forms and mutual relations of the more or less differentiated masses,
and from this condition every intermediate phase may be followed
to the most perfect parallel banding. Many causes have doubtless
operated in the production of the results which we now see, and
much work will have to be done before all these causes are clearly
recognized, and the effects of each accurately defined. One great
difficulty, with which the geologist has to contend in his attempt to
unravel the complicated story of the Lewisian gneiss, is that of
separating the effects due to causes operating before or during the
consolidation of igneous magmas from those due to dynamic action
operating upon the rocks after consolidation.
In the middle area — that is, in the district between Scourie and
Loch Inver, where innumerable basic and a few ultra basic dykes
clearly cut the fundamental gneiss — the existence of narrow belts of
country, * shear-zones/ as they have been termed, along which the
rocks have been affected by secondary dynamic action, can be clearly
demonstrated. Along these zones the granitic gneiss often becomes
granulitic, hornblende takes the place of augite, and quartz-veins
often make their appearance. The dolerite-dykes, where they abut
against the shear-zone, which is often also a line of fault, tail off
into hornblende-schist, and the ultrabasic dykes (in some cases at
least) into talc-gedrite-siderite-schist. Between these zones we find
areas which have certainly not suffered deformation since the dykes
were formed, and it is precisely in such areas that structures most
nearly allied to those of the banded gabbros are to be found.
The ultrabasic portions of Lewisian gneiss about Scourie and
Drumbeg may be especially referred to in this connexion, although
probably much of the banding in other localities and affecting other
kinds of rocks is of the same nature and origin. The separation of
the component minerals of these varieties of gneiss into definite
parallel bands presents so remarkable a resemblance to the structure
which we have described from the Tertiary basic rocks of Skye, that
it is difficult to believe that they cannot have arisen from the
same conditions.
Geologists now generally agree in regarding the older gneisses as
mainly rocks of igneous origin. And this view, as it seems to us,
is strengthened by the detection of so close an analogy between the
banding of these rocks and that of basic eruptive bosses. There
seems to be good reason to believe that this structure in the undis-
turbed igneous rocks is not a mere local accident, but that it occurs,
as at least an occasional phenomenon, among basic eruptions of
many different ages from Archaean to Tertiary time.
We suspect that much of the banding among the old gneisses, as
Digitized by Google
Quart. Journ. Geol. Soc. Vol. L. PI. XXVI.
■
Granulitic and Foliated Gabbro tra
Digitized by Google
Quart, Journ. Geol. Soc. Vol. L. PI. XXVII.
sed by later Veins of Felapathic Gabbro.
Digitized by Google
Quart Joum. Geol. Soc.Vol.L. PIXXVIIl
Vol. 50.] BANDED STRUCTURE OF BOMB TERTIARY OABBB08. 659
distinguished from mere foliation, which has been ascribed to late
mechanical deformation, may be an original structure due to the
conditions in which the igneous magma was erupted and con soli-
dated. In view, however, of the undoubted evidence of secondary
dynamic action in many regions, and in the absence at present of
any well-established criteria by which we can in all cases discrimi-
nate between original and secondary structures, we are not yet in
a position to define the exact limits within which the hypothesis of
the intrusion of heterogeneous magmas is applicable to the explana-
tion of the structures of the Lewisian gneiss.
EXPLANATION OP PLATES XXVI. -XXVIII.
Plate XXVI.
Folded and Banded Gabbros at Druim an Eidhne, 10 feet brood.
Plate XXVII.
Granulitic and foliated gabbro, traversed by later vein* of felspathic gabbro,
at Druim an Eidhne. The irregular white patches are the relics of veins
of felspathic gabbro.
Plate XXVIII.
Fig. 1 (5373 in Surv. Collect). From one of the light-coloured felspathic
bands. The minerals represented are plagioclase, uralitio hornblende,
and magnetite.
Fig. 2 (5377). From one of the dark bands rich in augite and magnetite.
The minerals present are plagioclase, augite, and magnetite. Some of
the augite-grains occur as inclusions in the interstitial magnetite.
Fig. 3 (5375). From a band of intermediate character. The minerals represented
are plagioclase, uralitic hornblende (scarce), and iron ore. The portion
of the slide selected for representation is exceptionally rich in magnetite,
which is seen to fill up the spaces between the felspars.
Fig. 4 (5376). From one of the black ultrabasic ' schlieren.' The only two
minerals present in the portion represented in this figure are augite
and magnetite.
Fig. 5 (5374). From one of the black ultrabasic ' schlieren.' Composed of
olivine, felspar, and magnetite. The magnetite occurs in veins tra-
versing the olivine, and also as grains independent of that mineral.
The plagioclase, which occupies the centre of the figure and fills up
the irregular space between the other minerals, belongs to one crys-
talline individual.
Fig. 6 (5374). Another portion of the same slide. The minerals here repre-
sented are olivine, augite, and magnetite.
Discussion.
Dr. Johuston-Lavis wished to know if there was any special
orientation of the crystals in the different bands, and also whether
the thinner bands were the raoro basic, as those facts would help to
elucidate their origin. He quite agreed with the Authors that the
differentiation of the magma was anterior to its taking up its
present position. He remarked that frequently effusive rocks
showed a banding of this nature due to differential shearing between
portions of the magma of different viscosity, and such might be the
Q. G. J. 8. No. 200. 2 z
■660 BAJTDBD STRUCTURE OP BOMB TERTIARY GAB BROS. [NOV. 1 894,
case also in injected rocks : hence the reason of the questions that
he had put
Prof. Blare remarked that one of the Authors, after paying
a visit to Anglesey, had described the general aspect and structure
of certain gneiss-like rocks in almost identical terms with those now
used for the gabbros of Skye, which the Authors regarded as
Tertiary ; yet, on the ground of such aspect and structure, the
Anglesey rocks were considered to be of the age of the Hebridean
gneisses. He hoped that it would now be admitted that the age of
rocks could not by these particulars alone be determined.
Dr. Hicks said that the facts stated by the Authors were very
interesting, as bearing on the possiblo cause of the banded structure
in some of the Lewisian gneisses. It was now generally admitted
that the more massive of the pre-Cambrian gneisses must have had
an igneous origin ; but the mode by which the banding had taken
place remained somewhat doubtful.
The point raised by Prof. Blake was easily disposed of, as it was
seldom necessary to rely upon petrological characters only ; and in
the case of the Anglesey gneisses there was good stratigraphical
evidence to show that they were of pre-Cambrian age.
Mr. Habiter found the paper of much interest from a purely
petrographical point of view, as well as for its bearing on the origin
of ancient gneisses. Banded structures are well known in many
basic plutonic masecs, but the examples described in this paper are
more striking than any hitherto recorded.
Mr. J. Hort Plates also spoke.
Sir Archibald Geixie stated in reply that, so far as he knew, no
relation was observable between the breadth of the bands in the
gabbro and their basicity, nor at the locality referred to in the
paper was there any marked orientation of the crystals parallel to
the planes of banding. Among some of the basic sills of the
Western Isles, however, such orientation was strongly developed,
and he particularly cited a troctolite sheet in the Island of Rum, in
which the laminar arrangement was so conspicuous that the rock
might at first be mistaken for a schist. The observations recorded
in the paper did not seem to him to have any bearing on the age of
the rocks in the centre of Anglesey, referred to by Mr. Blake,
regarding which his opinion remained unchanged.
Vol. 50.] 0LKNBLLUS-Z02TE OF THB KOBTH-WB8T HIGHLANDS. 661
41. Additions to the Fauna of the Olenbllvs-zone of the Nobth-
wbst Highlands. By B. N. Peach, Esq., F.R.S., F.G.S., of
the Geological Survey of Scotland. (Communicated by per-
mission of the Director-General of the Geological Survey.
Read June 20th, 1894.)
[Plates XXDL-XXXIL]
Pace
I. Introduction 6<>1
II. Description of a new Sub-genus and some new Species of Trilobitee ... 662
III. Theoretical Considerations based upon the Study of the Remains
described C71
I. Intboduction.
It is now two years since Mr. Home and I communicated to this
Society details of the discovery by the Geological Survey of OleneUus
in the * Fucoid Beds ' and Serpulite Grit of the west of Ross-Bhire,
which in our opinion proved the Lower Cambrian age of those strata.
The discovery has been followed up by the Survey, and through
the kindness of Major Robertson, the shooting tenant, and of
Mr. A. P. Purves, the agent for Mr. Mackenzie, the proprietor of
the Dundonnell Forest, facilities were afforded to Mr. A. Macconochie,
Fossil Collector of the Survey, which allowed him to make a more
exhaustive search of the localities mentioned in our paper. The
search resulted in his obtaining a considerable amount of new
material.
While the work of the Survey was advancing in the region around
the head of Loch Maree, prior to the discovery of OleneUus at
Dundonnell, certain outcrops of the ' Fucoid Beds ' were considered
fossiliferous, and were accordingly marked off to be further searched
by the collector. One of these, situated in Glen Cruchallie, more
commonly, though erroneously, known as Glen Logan, yielded
Mr. Macconochie specimens of Scdterella and Hyolithesf but no
recognizable fragments of trilobite. The other outcrop, noticed by
Mr. Greenly, occurs on the northern slopes of Meall a' Ghubhais at
a height of between 1200 and 1300 feet, just over the tree-line,
and about 4 miles north-west of Kenlochewe. As this locality iB
situated in the Sanctuary, or most carefully preserved part of the
Kenlochewe Deer Forest, it could not be searched when Mr. Mac-
conochie's services were available, owing to the approach of the
stalking season.
Early in the field-work of last year, Messrs. Home, Gunn, and
Clough had occasion to visit this locality, in order to study the
effects of movement on different members of the Torridonian Series,
which have there been thrust over the Cambrian rocks and left as
an outlier by denudation to form the upper part of Meall a' Ghubhais.
2z2
Digitized by Google
662
WK. B. N. PEACH ON THE FAUNA OF THE
[Nov. 1894,
At the same time, they made a short search at this exposure of the
' Fucoid Beds/ which, although they lie not far beneath the outcrop
of the * thrust-plane/ are comparatively free from disturbance.
Mr. Homo found a fine specimen of AcrotheU sutmdua, a small
brachiopod which is associated with the OfeneZ/i/^fauna in Utah
and Nevada. Mr. Macconochie was soon afterwards despatched
to Eenlochewe, and having bad every facility afforded him by
Mr. Cazalet, the tenant of the forest, soon struck upon the beds
which yield Olenellus, and made a fine collection. He likewise
returned to the outcrops in Glen Logan and proved the occurrence
of Olenellus in the * Fucoid ' Shales there ; but, in consequence of
the strata being much affected by post-Cambrian movements, the
specimens are too indistinct for description. The collections thus
secured were placed in my bands, as acting Palaeontologist to the
Geological Survey of Scotland, and, by permission of the Director-
General, I now beg to lay before this Society as a sequel to the
former paper 1 a description of the trilobite-remains.
II. Description of a new Sub-sen us and some new
Species of Tkilobites.
The trilobite-remains in this collection consist of sevoral hundred
fragments, chiefly head-shields, a few nearly complete individuals
with both head-shields and body-segments attached, several minor
fragments affording good material for study, and a large number of
pieces that may be called scraps. These various specimens enable
me to complete the account of the structure of Olenellu* Lapworthi,
described by me from head-shields alone, as well as to announce
tho existence of other species of tho genus. Moreovor, the specimens
include numerous head-shields and one almost complete individual
that appears to belong to a separate sub-genus.
Genus Olenellus, Hall.5
Olenblltts Lapworthi, Peach. (PI. XXIX. figs. 1, 2, 2 a ; PI. XXX.
% 7.)
Head-shield described in a former paper.' Body-segments,
fourteen in number, all free, with well-embossed axes divided from
the pleura by shallow axal furrows, and each bearing in the mid-
line near the posterior margin a small tubercle or short spine. The
pleura, which are wide, with thickened fulcral margins, well-marked
fulcral grooves, and thickened posterior margins, are bent back
suddenly upon themselves opposite the end of the fulcral groove,
and terminate in a more or less produced, recurved spine. The axes,
which, next to the head-shield, are nearly as wide as the occipital
ring itself, carry their breadth down to tho third segment ; thence
they diminish backward till the axis of the fourteenth segment
is a little less than one half the breadth of the first.
1 Quart. Journ. Geol. Soc. toI. xlviii. (1892) pp. 227-241.
3 The genus Olenellus is here used in the restricted sense explained in my
former paper, op. cit. s Ibid.
Vol. 50.] OLENBLLUS-ZONK OF THE NORTH-WEST HIGHLANDS. 663
The relation of depth to breadth is nearly the same in all the
axes, and varies in the proportion of 1 : 3 or 3 : 8. The pleura,
in consequence of overlapping each other, are a little deeper
than the corresponding axal portions. Those of segment No. 1
are directed slightly forward, and preserve their full breadth as far
as the pleural angles of the head-shield, where they are abruptly
truncated, their postero-lateral angles being each set with a short
spine. In segment No. 2 the pleura are set at right angles to the
general axis of the body, and extend to the tips of No. I ; but
they are not so sharply truncated as in that segment, being bent
back and ending in rather longer spines.
The pleura of segment No. 3 form a most conspicuous feature.
They gradually expand from the axis outward till they attain
double its breadth opposite the pleural spines of the preceding
segment, beyond which they suddenly bend off at almost right
angles, taper rapidly, and are continued into more or less flattened
spinos nearly as long as the ploura themselves. The fulcral ridges
and grooves are also more pronounced on this segment than on any
other.
In consequence of the great expansion of the pleura of segment
No. 3, those of No. 4 are directed slightly backward. They are
much narrower and shorter than the pleura of the former segment,
their fulcral points being well within its posterior curves. like
those of No. 1, they terminate abruptly, but their spines aro a little
longer than in that segment. In No. 5 the pleura are set more
distinctly backward, and are a little longer in proportion to the
size of the axis than those of No. 4 ; their terminal spines also are
somewhat longer.
In segment No. 6 there is a suddon increase in the size of the
pleura, especially in the spines, that reminds one of No. 3. The
succeeding four segments are all much like No. 6 in appearance,
though tho pleura of each are set at a smaller angle to the axis
than the immediately preceding ones, and the spines are each in
turn more bent inward towards their tips in order to prevent over-
lapping.
The hindermost four segments have their pleura set at an in-
creasingly acute angle to the axis, till the posterior margins of those
of the fourteenth segment almost coincide in direction with it, while
their spines rapidly and successively become smaller.
The telson has not been observed in place, but it is presumed
that it is styliform, precisely as in tho variety of this species which
will be subsequently described. The whole of the parts are more or
less marked by the peculiar reticulated pattern described in my
former paper (op. cit. p. 239, pi. v. fig. 2 6). This sculpture is
most conspicuous on the glabella and cheeks, and on the anterior
portion of the axes and the pleura of the body -segments. In this
species it is small, compared with the size of tho animal.
The chief character which distinguishes OhneUus Lapworthi from
664
MR. R. N. PEACH ON THE FAUNA OF THE
[Nov. 1894,
all the American species as yet described is that the posterior
angles of the eye-lobes are sot much farther out from the edge of
the glabella in this species — a character which it shares in common
with all the other species in the collection under review. From
Olendlus Thompsoni and 0. Gilberti, which it most nearly approaches,
it is further distinguished by the line of tubercles ranging from
the occiput, and extending down the axes of all the segments.
Table of Measurements of OUndlus Lapworthi.
M. 4085*.
PI. XXIX. fig. 1.
M. 4078*.
PL XXIX. figs. 2 & 2a.
Length of head-shield and Brat
Length of head •shield and body-
segments, exclusive of telson ...
in tn.
25
13
26
mm.
20
9
20
The figures at the top of the columns are the registered numbers of the
specimens in the books of the Geological Surrey of Scotland.
Oi.enellub Lapworthi, var. elongatus, nov. (PI. XXIX. figs. 3-6.)
This name is proposed to include the more elongated forms of
this species. Fig. 3, PL XXIX., represents a nearly complete
specimen enlarged two diameters. In general contour of the body,
it is somewhat more elongated than 0. Lapworthi. Its specially
distinguishing feature, however, is the unusually developed pleural
spines of the third body-segment, which not only extend much
farther backward than in that species, but are curved inward in
the same manner as in Ohnellus Gilberti, a species found on the
side of the Rocky Mountains opposite to that wherein 0. Thompsoni
has been found. Like the former, it appears to have terminated
in a long spear-like telson, portion of which is seen in fig. 3,
PL XXIX., which is too imperfect to show the details of its con-
figuration or to indicate its probable length.
Several fragments of the third body-segment of this form are
preserved in the collection under review. The test of this variety
is ornamented with a sculpturing similar to that of 0. Lapworthi.
A portion of a labrum which seems to belong to this variety is
reproduced in PL XXIX. fig. 5, magnified two diameters.
The specimen from which fig. 3, PI. XXIX., was taken gives the
following measurements : —
Full length without telaon 22 mm.
p. *ith , 25 „
Length of carapace 10 „
Breadth of do 19 „
n body across third segment ... 14 „
Digitized by Google
Vol. 50.] OLENELLUS-ZONE OF THE NORTH-WEST HIGHLANDS. 665
Olenellus rbttculattts, sp. nov. (PI. XXX. figs. 1-6, 8-14 J
PI. XXXI. figs. 1-7.)
In the collection under review there are numerous remains of an
Olenellus of much larger size than 0. Lapworthi, which in many-
other respects it greatly resembles. The reticulated ornament on
its test appears to be much larger in pattern (compared with its
size) than in that species, and this difference, which makes it con-
spicuously visible to the naked eye, has suggested the specific name
which I propose for the new form. In general aspect it much
resembles the elongated variety of 0. Lapworthi. It differs from
that chiefly in the head-shield, which is deeper in comparison with
its breadth. The glabella is longer in proportion to the size of the
head-shield, and the individual lobes are each more elongated, while
the angles made by the furrows with the general axis of the body
are more acute. The distal ends of the eye-lobes are not so far
removed from the edge of the glabella, nor do they extend so far
backwards, but end well in front of the fourth furrow, while those
of 0. Lapworthi extend beyond it. The raised margin that bounds
the cheeks is not so wide in proportion ; the genal spine is more
slender, and is placed a little more anteriorly, and the notch between
it and the pleural angle is deeper than in 0. Lapworthi.
The arrangement of the details of its body-segments is similar
to that of 0. Lapworthi, but the peculiarities of the pleura of the
third segment are even moro pronounced, the spines being longer
relatively, and sometimes more incurved. The spines on the pleura
of the sixth and three succeeding segments are longer and more
slender. Tubercles have been observed in the mid-line on the
occipital ring, on the axes of the first three free segments, and on
several of the posterior ones. They have not been observed on all
the intermediate segments, but this may be owing to bad preser-
vation or faulty observation, as it is probable that they once existed.
The telson is long and styliform, and tapers rapidly at first aud
then decreasingly. Its articulation with the last free segment is
well shown in tho specimen from which PL XXX. fig. 12 was taken.
Projecting from the posterior margin of the axis of the fourteenth
free segment, at about £ of its width from each side, are two small
protuberances. Corresponding projections proceed forwards from
the hinge-line of the telson, and interlock with them on their outside.
Beyond them the anterior edge of the telson is continued in nearly
the same line with the hinge, so that the anterior angles of the
telson appear to be overlapped by the pleura of the last free segment.
A * lock joint ' is thus formed which does not allow of the telson
folding downward beyond a certain anglo with the plane of the
last segment.
A detached labrum which may have belonged to an individual of
this species is shown, nat. size, in PI. XXX. fig. 13.
There appears to be a considerable range in the configuration ol
different individuals of this species. PI. XXXI. fig. 3 represents
an elongated form which appears to have been even further elon-
gated, and in fact distorted after having been embedded in the rock.
Digitized by Google
666 MR. B. N. PEACH ON THE FAUNA OF THE [Nov. 1 894,
PI. XXXI. figs. 1 and 2 show what appears to be a broader form,
but it has been distorted first by having tho first two free segments
4 telescoped ' into the head-shield, and by having the body folded
upon itself at the eighth free segment, the dorsal tubercle of which is
well seen against the matrix at the fold. By a fortunate breaking-
away of part of the test which adheres to the counterpart, the
pleura of the hindermost segments and tho greater portion of the
tel&on can bo observed at a lower level in the matrix. Since it has
been embedded, the specimen has been further broadened and dis-
torted by faulting of the matrix.
Table of Measurements of Olenellus rtticulatus.
M. 4104<.
M. 4161*.
M. 4142'.
M. 407M.
M. 4«W».
PI. XXX.
PI. XXX.
PI. XXX.
PI. XXXI.
PL XXXI.
PI. XXX.
flg. 1.
flg. 2.
i, a.
g.3.
flg. ft.
mm.
mm.
mm.
mm.
mm.
Full length of parts pro-
60
Length of head -shield ...
29
33
••••••
27
Breadth of do.
50
46
60
50
40
40
27
„ eight segment*
33
Breadth of third segment
40
36
24
Length of spine of do....
Length of telson risible. . .
22
20
20
15
Olenellus gioas, sp. nov. (fig. 1, p. 667).
Fragments of a large species of trilobite with a strong genal spine
and reticulated ornament were figured in a former paper (op. jam
ext. pi. v. figs. 12, 12 a, 126). In the present collection a specimen
occurs which gives most of the detail of the dorsal aspect of the
head-shield : this is much wider compared with its depth than in
0. Lapworthi and 0. rtticulatus. It is further distinguished from
the latter by its broad margin and strong genal spine. The orna-
mentation is readily seen, even with the unaided eye. As stated
in the former paper, the pattern of the reticulation is more elongated
on the margins and spines than on the general surface, but this
applies equally to all the species of Olenellus,
Portions of cheeks and genal spines of individuals nearly as large
as the above, on which the pattern of the ornamentation is much
smaller proportionally to their size, occur in the collection.
Measurements of carapaco of Olenellus gigag, M. 11544 : —
Length of head-shield 52 mm.
Breadth of do. 106 mm. =4^ inches.
Olenellus intermedius, sp. nov. (PI. XXXII. fig. 7.)
This species is founded on a single head-shield, preserved in relief
in a decomposing ochreous bed, and its counterpart. It is doubtfully
Digitized by Google
Vol. 50.] OLENELL178-ZONE OF THE NORTH-WEST HIGHLANDS. 667
placed in the genus Olenellut, As it combines several of the features
of the sub-genera of Olcuflliut, I have given it the specific name of
intermtiliug.
Fig. L — OUnellu* ;/igas, sp. nov. (Natural size.)
The head-shield is roughly hexagonal, the anterior and posterior
sides of the hexagon being much the longest, so that the shield is
wide compared with its depth. The anterior margin, which forms
three sides of the hexagon, is divided into a long median section,
which is slightly convex, bent round at obtuse angles and con-
tinued into the other two sides ; these are straight and produced
backwards into strong genal spines, the whole margin being
strengthened by a well-rounded ridge. The posterior margin makes
up the other three sides of the hexagon. The median portion,
made up of the margin of the occiput and the edge of the cheeks
as far as the pleural angles, is convex. At the pleural angles
arc placed two spines (Ford's ' interocular spines '). The margin
between these and the genal spines is defined by almost straight linos,
which form the remaining sides of the hexagon. It is thickened
in the same manner as the anterior margin.
The cheeks are tumid and divided from the raised margin, the
glabella, and the eye-lobes by a depression. A groove, continuous
with that of the occipital groove of the glabella, is produced out
towards the base of the spine upon the pleural angle. No free
cheek nor facial suture has been observed. Tho glabella, which is
highly embossed, extends from close upon the thickened anterior
66S
MR. B. N. PEACH ON THE FAUNA OF THE [Nov. 1894,
margin to the posterior margin, is rounded in front, broadest at the
base of the eye-lobes, and narrowest to just behind the second
furrow. It then increases in breadth backward. It is divided
into five lobes by furrows which are not so much bent backward in
the middle as in 0. LapwortfU. A small tubercle occurs on the
occipital ring. The eye-lobes are reniform, and set out at more
obtuse angles than in any of those already described ; they extend
back only so far as to be opposite to the second glabellar furrow.
The area in the angle made by the glabella with the eye-lobes is tumid.
The test is ornamented with the characteristic reticulate pattern.
Measurements : —
Length of head-shield 3 mm.
Breadth of do 7'5 „
Length of genal spine 25 „
Olenelloides, subgen. nov.
The collection of fossils from Meall a' Ghubhais contains numerous
head-shields, and one specimen and its counterpart with head-
shield and eight body-segments attached, of a peculiar, small, narrow
trilobite armed with long spines at regular intervals. It is evident
that it is nearly allied to Olencllus, in which genus I should prefer
to allow it to remain ; but though all the specimens may belong to
only one species, yet the individuality of that species is so strongly
marked that perhaps it would be better to place it in a separate
sub-genus taking rank with Jlolmia and Metonacis under Olencllus.
The name that I have proposed for it is intended to show its strong
likeness to some larval stages of other Olenellids.
Description. Small, elongated, and narrow in general outline, and
set with long spines at regular intervals.
Head-shield roughly hexagonal, produced into long and strong
spines at all the angles, and strengthened on all sides except the
posterior one by a strong, rounded, raised margin, which is widest at
the angles. Its greatest width is across from base to base of the
mid-pair of marginal spines. The glabella, which occupies about
half the area of the head-shield, is well embossed, almost cylindrical,
divided into five distinct lobes, and extends nearly the whole length
of the shield. It is rounded in front, slightly constricted near the
second furrow, and widest at the occipital ring, which bears a small
blunt tubercle in the mid-line. The eye-lobes are reniform, pro-
ceeding out from the frontal lobe just in front of the first furrow,
and with their distal ends well set out from the glabella. The visual
slits occupy nearly the whole length of the outward or convex
edges of the eye-lobes. No free cheeks nor facial suture.
Number of body-segments unknown. The characters of the eight
preserved show that the body was long and narrow, and that the
segments are well trilobed, with highly ombossed axes, which are
wide compared with the pleura. The latter are marked off from
the axal parts by a shallow furrow, have fulcral thickening in front,
wide fulcral grooves, and end in short spines at the postero-lateral
angles, except in the third and sixth segments, where the spines are
Digitized by Google
Vol. 50.] OLEXELLU8-Z0ITB OP THE NOBTH-WBBT H101UA5D8. 669
long and strong. The body suddenly narrows behind the sixth
segment, and the pleura of the seventh and eighth segments are
very small ; hence it is inferred that it would require only a very
few more segments to complete the body. Nature of telson
unknown.
The characteristic features of this sub-genus are the great size of
the axis of the body compared with the cheeks and pleura, the
hexagonal head-shield with its angles set with spines, and the
recurrence of larger pleura and highly elongated spines on the third
and sixth body-segments.
OLEIfBLLOrDE8 ABMATUS, Sp. nOV. (PI. XXXII. figS. 1-6.)
The head-shield, which is hexagonal and set with long spines at
the angles, is of about the same length as the first six body-segments
and varies in proportion in different individuals as 1 : 1 and 4 : 3.
It is bordered on five sides by a thickened, rounded margin, which
is widest at the angles. The anterior margin between the first
pair of spines is convex, and these spines are set forward at angles
of about 30° to 35c to the general axis of the body. The margins
between these and the lateral spines make almost straight lines,
the head-shield being at its widest opposite the bases of these lateral
spines, which are set backward at angles of about 50° to the axis
of the body. Behind these spines the shield tapers rapidly at first
and then more gradually, so that the margins between the lateral
spines and the posterior ones are concave. The posterior spines are
directed backward and set at an angle of about 30° to the long axis
of the body ; they are slightly curved inward towards their tips.
The posterior margin is convex, being made up of the posterior
margin of tho occiput, which constitutes f of the whole, the
remaining I being occupied by the margins of the cheeks, which
are marked off from the occipital part by deep notches. The
glabella, which is nearly cylindrical and rounded in front, extends
almost from end to end of the head-shield, and occupies the greater
part of the cephalic area. It is dividod into five lobes, wide in
front, narrowing somewhat at the lobe behind the first furrow, and
widest at tho occiput. The furrows are nearly M-ehaped, in con-
sequence of which the frontal lobe is pear-shaped and the others
are more or less cordate, the lobe immediately behind the first furrow
being tho smallest. The occipital lobe bears a small spine or
tubercle in the mid-line. The eye-lobes are reniform, proceed out
from the frontal lobe towards the outer margin, and terminate just
behind the bases of the lateral spines opposite tho third lobe of tho
axis, the ocular slit extending throughout the greater part of its
outer or convex margin. The cheeks in front of the eye- lobes and
glabella are hollow. A narrow ridge runs from the angle made by the
eye-lobe and the glabella as far back as to opposite the third furrow ;
another ridge runs from this furrow to the base of the posterior spine.
These ridges are separated from the glabella and eye-lobes by deep
furrows. No free cheeks nor facial suture observed.
Body-segments, number unknown, eight only being preserved.
Digitized by Google
670
Mil. B. N. PEACH ON THE FAUNA OF THE [Nov. 1894,
Each of these consists of a well-marked axis, very large in propor-
tion to the pleura, from which it is marked off by shallow axal
grooves, and bearing a tubercle or small spine in the mid-line near
the posterior edge. The axis of the first segment is of about the
same width as the occiput, and this width is maintained as far as
that of the third segment. From this point they taper gradually
backward to the aixth segment, behind which there is a compara-
tively sudden contraction, the seventh and eighth segments being
much smaller than any of the rest. The pleura, which are almost
quadrate in shape, have fulcral ridges and grooves, and spines
on their postero-lateral angles. These are small and insignificant,
except on the pleura of the third and sixth segments, which are
long and strong, and set backward at almost the same angle as the
posterior spines of the head-shield.
From the sudden tapering behind the sixth segment, and from the
nature of the pleura of the seventh and eighth segments, which are
especially small and set backward, it is inferred that the body
never bore many more than those exhibited. The nature of the
terminal segment or telson is unknown, though it was in all
probability styliform.
Some of the specimens show that the test was ornamented with
a reticulated pattern, as in Olendlus and other early trilobitee.
Table of Measurements of Oleneftaides armattui.
Length of head-Bhield and
eight segments, exclusive
of spines
Length of bead-shield, ex-
elusive of spines
Breadth of do
Breadth at anterior margin
„ „ posterior do.
Average length of emines on
head-shield
Average breadth of axis of
glabella
Breadt h of lstbodv-segment
„ of axis of do
Depth of do
Breadth of third segment .
of axis of do
Depth of do
Length of spine on do.
Breadth of sixth segment..
„ of axis of do
Depth of do
Length of spine on do
Breadth of seventh and
eighth segments ,
Depth of axis of do
M. 41 IK
M. 4116-.
M. 41 17*.
M. 4127*.
pl xxxn.
pl xxxn.
Pl. XXXII.
pl xxxn.
figs. 1-3.
fig. 4.
fig. 5.
fig. 6.
mm.
11
mm.
mm.
mm.
5
475
3
4
4
45
2-5
4
2
3
175
2-5
3
35
175
3
25
*5
25
175
35
175
1-25
175
1-75
1
375
1-75
1
226
2
1
•75
1-5
1
•4
Digitized by Google
Vol. 50.] OLENELLUS-ZONE OF THE FORTH- W EOT HIGHLANDS. 671
Genus Batbtnotus, Hall.
Bathtnotvs holoptoia? Hall.
Some fragments consisting of a portion of a glabella and fixed
cheeks, and several slender spines of trilobitos which cannot well
belong to any known species of OUiielltu, but which fairly auswer
to the description of parts belonging to Bathynotug holopi/f/ia, occur
in the collection under review, and have been provisionally earned
as above till such time as further evidence regarding their nature
is forthcoming.
III. Theoretical Considerations eased upon the Study of
the Remains described.
Having described these trilobites, I may now proceed to compare
them among themselves and with other known Olenollida, and
endeavour to correlate their homologous parts. In all the Olenellids
the glabella and eye-lobes are so similar, that no difficulty arises in
correlating part with part. It is not so with the marginal spines
of the head-shield. The spines upon the pleural angles of the
posterior margin in Olcncllus intermtditu, PL XXXII. fig. 7, and
so strongly pronounced in Oltnelloides, PI. XXXII. figs. 1-6, are
represented in the other forms in the collection by the rounded-off
pleural angles. They have been shown by ford and Walcott to be
present in young stages of the American Metonacit (Olenellus) asa-
phoides, PL XXXII. fig. 11, and to disappear into the rounded
pleural angles in the adult. They are present as spines in llolmia
(Oknellus) Kjerulfi, PL XXXII. fig. 12, and in tho other described
species of this genus. A study of fig. 12 (after Holm) reveals that
they are, in all probability, the pleural spines of a segment com-
parable with one of the freo body-segments, the traces of tho axis
and pleura of which have not been obliterated by its fusion with
tho other segments of the head-shield.
The genal spines of moBt Olenellids occupy the postero-lateral
angles of the head-shield. That this was not their original position
is made almost certain by the researches of 8. W. Ford and Walcott,
who have shown that in some of the young stages of Olencllu*
Gilf>erti, PL XXXII. fig. 9, these spines may be produced in a lino
with the anterior margin, and that they travel round as the animal
gets older, PL XXXII. fig. 10. In OUrulhides, PL XXX11.
figs. 1-6, we have an adult form which shows these spines placed
about halfway between the anterior and posterior margins. That
they have travelled back from a more anterior position is rendered
probable by the margin behind them being concave. If that be the
case, the notch between the genal spines and the pleural angles
in Olentllus, Holmia, and Mesotuicis represents what has once been
a lateral margin. This inference is supported by evidence gained
from the study of tho ornamentation on Olenellus. In the paper
read before this Society in 1892 I pointed out that the polygonal
pattern of the test becomes highly elongated on the thickened
672
MB. B. 5. PEACH ON THE FAUNA OP THE
[Nov. 1894,
I
margins, the elongation being more or less parallel with the outside
edge. In Olenellus reticulatus and 0. giyas this elongated pattern
is continued inward beyond the genal spines, but ceases at the
pleural angles, the pattern on the raised spaces between these latter
points and the Bides of the occiput being similar to that found on
the pleura of the first free body-ring. If it has been shown that
there is good reason to believe that what have once been lateral
margins have become posterior, the difference between those trilobites
whose facial sutures terminate upon the lateral and posterior margins
respectively may be more apparent than real.
No exact homologues of the anterior spines in Olenelloides have been
observed. It may be that the rounded anterior angles of Olenellus
intermedins, PI. XXXII. fig. 7, represent the places where such
spines have disappeared. As I have already shown, the elongated
spines recur at intervals of every third segment on the body of
Olenelloides, PI. XXXII. figs. 1-3, and there is a strong presumption
in favour of the posterior spines of the head-shield being the repre-
sentatives of the pleural spines. The idea suggests itself that the
genal and even the anterior spines may represent such elongated
pleural spines, in which case, if the intervals between them be the
same as in the body, the head-shield may represent at least seven
original segments. At first sight, it looks as if this arrangement
of more pronounced spines at regular intervals were confined to
Olenelloides, but there is a slight recurrence of the phenomenon in
Olenellus Lajnvorthi and 0. reticulatus, for while in them the pleura
of the fourth and fifth segments are short and like those of the
first and second, those of the sixth segment suddenly expand
and bear longer recurved spines. Behind this latter segment the
analogy ceases, for the sixth is followed by three or four similar
segments.
So far as dorsal spines are concerned, it is an easy matter to
correlate them, notwithstanding the fact that some are mere raised
tubercles and others enormously-produced spines like those on
Holmia Broygeri, Mesonacis asaj)hoides, M. vermontana, and M.
Mickwitziir. Keeping this in view, it is not difficult to see in the
hastate telson of Olenellus the homologuc of the small pygidium of
Holmia and Mesonacis, each being a single segment. In the former
case the dorsal spine has been enormously developed and the rest
of the structure dwarfed, while in tho latter case the corresponding
spine is rudimentary. (See fig. 2, p. 673.)
The question naturally arises as to what could be the function of
the spines. Concerning those that fringe the edge of the head and
body, it is highly probable that they served to prevent the bearers
from sinking into soft, flocculent sediment, and so being stifled. As
the genital organs in annelids and most arthropods open well
forward in the body, it may be that the function of the enormously-
expanded pleura of the third body-segment iu Olenellus was to pro-
vide space for enlarged genital glands about this region of the body,
and, as suggested in the former paper, the form of the pleura and
their spines may even denote sex.
le
Vol. 50.] OLEITELLU 8-ZON E OP THE NORTH-WEST HIGHLANDS. 673
The absence of faceted pleura shows that these Olenellids had
not acquired the habit of rolling up, so that dorsal spines such as
those found on MfsonaeU and Jlolmia were probably protective.
If so, one asks, what was the nature of the enemies from which
these creatures had to defend themselves? We may infer that
Fig. 2.
A = OlcneUut reticulatus, last two body-segments and telson.
B = Mesonacis Mickvoitzia, eighth body-segment. (After Schmidt)
C = Mesonaci* amphoidee, thirteenth body-segment (After Walcott)
they were large, for Holmia Brlkjgeri and Mesonacis amphoides are
of considerable size. That small enemies preyed upon them, living
or dead, is made certain by the occurrence in the collection under
review of Olenellus-syinee which have been bored by some annelid
or other animal before fossilization, PI. XXXII. figs. 13-15. The
strong spiniform telson may have been used by OleruUus for purposes
similar to that fulfilled by the telson in the recent Limulus.
The study of these Olenellids plainly shows them to have been
very primitive trilobites. They have all their body-segments free.
Their glabella is long and cylindrical, and divided into lobes by
well-marked furrows. Their eye-lobes are outgrowths from the
glabella, and have not wandered far from the primitive axis of the
body. There is good evidence for the belief that the occipital or
nuchal ring has been once a free segment, and the last to be added
to the head-shield, and that the genal spines have travelled back
from a more anterior position.
Of all the Olenellids yet described Holmia (Olenellus) Kjerulfi is
the most generalized. None of its body-segments are so specialized
as to make it conspicuous among its fellows, nor are any of its
spines, except the genal ones, more elongated than its neighbours.
Its nuchal or occipital segment is much like one of its free segments,
but it is fused to the preceding segment instead of being articulated
with it. Its genal spines are intermediate in position between
those of Olenelloides and Olenettus, in which respect it is not quite
so primitive as the former. From it all the other forms as yet
Digitized by Google
674 MR. B. N. PEACH ON THE FAUNA OF THE [Nov. 1 894,
described, except Olenelloides, could easily be produced by exagge-
ration or suppression of some of its spines, or by addition to or
diminution from the number of its body-rings. From Holmia (0.)
Kjerulfi (Linnarsson), as a central type, it would require a less
amount of modification to produce the H. (0.) Callavei (Lap worth)
of Shropshire than the II. (0.) Brbggeri (Walcott) of Newfoundland ;
and in like manner the Mesonacis (0.) Mickwitziar (Schmidt) of
Russia than the M. (0.) vermontana (Hall) or M. (0.) ataptioides
(Emmons) of America. Further, the species of Olenellus found in
the North-west Highlands of Scotland would require less modifi-
cation than the Olenellus Thompsoni (Hall) or 0. Gilherti (Walcott)
of America. The consideration of these points makes it probable
that the dispersal of the Olenellids was from the Old towards the
New World.
EXPLANATION OP PLATES XXIX.-XXXIL
Plate XXIX.
Fig. 1. Olenellus Lapworthi. Underside, with imperfect labrum in place. En-
larged 2 diameter*. From 4 Fucoid Beds,' Meall a' Ghubhais, Ken-
loci: tewe, Boss-shire. M. 408541.1
Fig. 2. 0. Lapworthi. Enlarged 2 diameters. Same locality and formation.
M. 4078d.
Fig. 2a. 0. Lapworthi. Counterpart of fig. 2. M. 4078*.
Fig. 3. 0. Lapworthi, var. elongatus. Enlarged 2 diameters. Same locality.
M. 4060*.
Fig. 4. 0. Lapworthi, var. elongatus. Enlarged 2 diameters. Same locality.
114089*.
Fig. 4a. 0. Lapworthi, var. elongatus. Counterpart of fig. 4. M. 408911*.
Fig. 5. 0. Lapworthi, var. elongatus. Enlarged 2 diameters. Labrum supposed
to belong to this variety. Same locality.
Fig. 6. 0. Lapworthi, var. elongatus. Enlarged 2 diameters. Pleuron of third
segment. Same locality.
Plate XXX.
Fig. 1. Olenellus reticulatus, nat. size. From * Fucoid Beds,' Meall a' Ghubhais,
Kenlochewe, Ross-shire. M. 407ft*.
Fig. 2. 0. reticulata, nat. sire. Underside of head-shield. Same locality.
M. 4104d.
Fig. 3. O. reticulatus. Portion of fig. 2, enlarged, to show nature of ornamen-
tation.
Fig. 4. O. reticulatus, nat. sire. Same locality. M. 4l61d.
Fig. h. 0. reticulatus, nat. sire. Fragment of head-shield. Same locality.
M. 4093d.
Fig. 6. 0. reticulatus, nat. sire. Underside of right pleuron of third body-
seguient. Same locality. M. 4103a.
Fig. 7. 0. Lapworthi. Enlarged 3 diameters. Third body -segment Same
locality.
Fig. 8. 0. reticulatus. Last four segments enlarged, to show pleura and
rudimentary spines on axes. Same locality. M. 4078d.
Fig. 9. 0. reticulatus. Last three segments magnified, to show pleura and
spines on axes. Same locality. M. 4109d.
Fig. 10. O. reticulatus. Body-segment* from the tenth to the thirteenth
inclusive, magnified to show pleura and spines on axes. Same locality.
M. 4102*.
1 These are the registered numbers of the specimens in the List-books of
the Geological Survey of Scotland. The M stands for Macconocbie.
Digitized by Google
Quart. Journ. Geo! .Soc.Vol.i. PI XXIX
S 11 Pe*cK del F H Michael l.ih. Minlsm Bro* »?np
01.FNFl.LUS I.APV/ORTH1.
Digitized by Google
Quarl.cJourri.GeoL. Soc.Vol. J . PI. XXX.
l.
Digitized by Google
Quarl.Joum.Geol Soc Voi L. PI. XXXI
Digitized by Google
Quart Joum.Geol. See Vol . L .Pi. XXXII
O LK M E I..LO IDH S , OLEN El .LU S ,
MESOMAC1S &.HOLMIA
Digitized by Google
Vol. 50,] OLEITBLLUS-ZONB OP THE HORTH-WBST HIGHLANDS. 675
Fig. 11. 0. reticulata*. Detached body segment from posterior part of body,
nat. size, to show rudimentary spine on axis.
Fig. 12. 0. reticulata, nat. size. Showing several body-segments and the
nature of the articulation of the telson. Same locality. M. 40774.
Fig. 13. 0. reticulata nat. size. Detached labrum, supposed to 'belong to
an individual of this species. ' Fucoid Beds,' AUt an Bigh Jan,
Dundonnell, Boss-shire.
Fig. 14. 0. reticulatus. Portion of largest individual observed.
Platb XXXI.
Fig. 1. Olenellus reticulatus, nat. size. Shows the first two body -segments tele-
scoped into the bead-sbield, the body being bent over at the eighth
segment. Telson seen where the pleura or the left side have broken
away, with counterpart. From 4 Fucoid Beds,' Meall a' Gbubhaia,
Kenlochewe, Boat-shire. M. 4142*.
Fig. 2. 0. reticulata , nat. size. Counterpart of fig. 1.
Fig. 3. 0. reticulatus, nat. size. Distorted by the glabella being driven obliquely
over the cheek. Same locality. M. 4078*.
Fig. 4. 0. reticulatus. Counterpart of fig. 3.
Fig. 5. 0. reticulatus, nat. size. Same locality. M. 409 1*.
Fig. 0. 0. reticulatus. Counterpart of part of fig. 5.
Fig. 7. 0. reticulatus, nat. size. Left pleuron of third body-segment. Snme
locality.
Platb XXXII.
Fig. 1. Olenelloides armatus. Enlarged 3 diameters, showing the outer side of
the right half. ' Fucoid Beds,' Meall a' Gthubhais, Kenlochewe, Eos*-
shire. M. 41 IK
Fig. 2. 0. armatus. Enlarged 3 diameters, showing the inside view of the
left side. Counterpart of fig. 1. M. 41 1 l-\
Fig. 3. 0. armatus. Enlarged 3 diameters. Dorsal view of 1 and 2 combined.
Fig. 4. 0. armatus. Enlarged 3 diameters. Brood head-shield. Same locality.
M.4116*.
Fig. 5. 0. armatus. Enlarged 3 diameters. View of inside of elongated bea<l-
shield. Same locality. M. 4117d.
Fig. 6. 0. armatus. Enlarged 3 diameters. Medium form of head-shield.
Same locality. M. 4127*.
Fig. 7. Olenellus intermcdius. Enlarged 3 diameters. Head-shield. Same
locality. M. 41494 and 4149".
Fig. 8. 0. Lapworthi, nat. size. Small head shield, to compare with figs. 4-7,
showing that in this species the genal spine is at the posterior angles
even in youn^ indi\iduals. Same locality.
Fig. 9. 0. Gilberti (Walcctt), after Ford and Walcott. Young stage, where
the genal spines are placed far in advance, and given off in almost
the same straight line as the anterior margin.
Fig. 10. 0. Gilberti (Walcott), after Ford and Walcott. Young stage, in which
the genal spines have travelled a little farther round than in fig. 9.
Fig. 11. Mesonacis (O.) asaphoides (Emmons), after Walcott. Y'oung stage, in
which the spines are still retained at the pleural angles.
Fig. 12. Holmia ( U.) Kjerulfi. (Linnarsson), after Hulm, showing the head-shield
and the first two free body-segments. Portion of the glabella is
removed, to show the labrum in position benoath.
Fig. 13. Spine of Olenellus gigas bored by annelid ? Nat. size. Meall a'
Ghubhais. Kenlochewe, Boss shire.
Fig. 14. Counterpart of fig. 13.
Fig. 15. Spine of Olenellus, bored by annelid ? Nat, size. Same locality.
Q.J.G.S. No. 200. 3 a.
Digitized by Google
676 OT.J»BLLr8-Z01?B OP THE NOBTH-WI8T BI6HLAND8. [Nov. 1 894,
DlSCUSSIOff.
Dr. Hicks said it was highly satisfactory to find that such
important additions had hecn made to the Ohtullus-iaxmA of the
North-west Highlands. He would have liked to hear further details
than could be given in the abstract just read, especially as to
whether the new species marked distinct zones or whether they
occurred together. In the Farad oxides-beds in South Wales, the
new species did not occur together, but were separated by various
thicknesses of beds. Where the deposits were sandstones the range
was much greater than where they were made up of finer materials.
The Olentllus-ione at St. David's was separated by over 800 feet of
sandstone beds from the lowest Paradoaidfs-zono, and the latter by
nearly 2000 feet of strata from the highest P«radoxide*-zone. There
were no less than five distinct zones, each marked by a new species.
He had found it necessary from the first, more than 30 years ago,
to mark the zones with great care, and it was by that means, when
working afterwards in North Wales, that Mr. Salter, Mr. Homfray,
and himself were able to correlate the various subdivisions with
those at St. David's. He further said that in 1875 he prepared
a map, which is published in the Quart. Journ. of the Society
(vol. xxxi. pi. xxvii.). In that map he gave the distribution of the
Cambrian and Lower Silurian faunas over the European area, and
he stated in the paper which it illustrated that he thought the
migrations were from the Atlantic in a north-easterly direction
over Europe, and in a north-westerly direction over America.
Dr. G. J. Hikde also spoke.
Digitized by Google
Vol. 50.] MB. P. CHAPMAN ON THE BABGATK BED8 OP SURREY.
677
42. The Baroate Beds of Surrey and their Microscopic Contents*
By Frederick Chapman, Esq., F.R.M.S. (Communicated by
Prof. T. Rupert Jones, F.R.8., F.G.S. Read June 20tb, 1894.)
[Plates XXXILL & XXXIV. ]
Contexts. Page
T. Introduction 077
II. The Bargnte Stone and Pebble-beds in Littleton-lane Quarry, near
Guildford 078
III. The Barbate Strata below St. Martha's Chapel (Chilworth) OS!
IV. Clay-eeuuis in the Bargate Pebble beds at Godnlming 087
V. Beds below the Folkestone Series in the Hornhani Road, south of
Dorking 087
VI. Oatmeoda and Foraminifera of the Lower Greensand 088
VII. Ostracoda from the Bargnte Pebble-bed» of Littleton and of
St. Martha's Hill (Chilworth) 088
VIII. Foraminifera from the Bargate Bed*, ortheirequivalents, nt Littleton, •
St. Martha's Hill (Chilworth), Godulnung, and Dorking 003
I. Introduction.
TnAT division of the Lower Greensand known as the Bargate Beds
is of especial interest on account of the varied character of its
organic and inorganic constituents, many of which are derived from
older rocks.
In 1856 1 R. A. C. Godwin-Austen wrote in reference to these heds :
" Whatever may have been the original range of the Oolitic group
over the area now covered by the Wealden and Cretaceous formations
of the S.E. of Kngland, there is evidence that it has been reduced
by the abrading action of the Lower Greensand sea along its coast-
line. The shingle-beds of the Lower Greensand of Surrey and
Kent contain, in addition to the materials already alluded to, a
considerable number of extraneous fossils, such as the bones and
teeth of Oolitic Saurians, Ammonite* Lamberti and A. crenatxig of
the Oxford Clay, in great abundance, together with Terebratula
fimbria and Rhynchontlla oolitica."
The correlation of these Bargate Beds, with others of Lower
Greensand age in the area east of that where the first-mentioned
occur, cannot be regarded as settled. The Bargate Beds have been
placed by the Geological Survey at the top of the Hythe series,*
whilst Mr. C. J. A. Meyer regards them as forming the basement
beds of the uppermost or Folkestone series.1
It is not my intention here to discuss at any length their strati -
graphical relations ; but a summary of the evidence gathered after
some detailed work in the Guildford and Dorking districts may be
of some use in correlating these strata. It has led me to regard
theso beds, which are intermediate between the Folkestone and
Hythe series, as fairly distinct from the upper and lower series
1 Quart. Journ. Geol. 8 00. vol. xii. p. 71.
2 W. Topley, Geol. Surv. Mem. ' The Geology of the Weald.' 1875, p. 121.
' ' On the Lower Orecniand of Godaluiing,' 1608, p. 10; in Suppl. to toI. i.
Proc. Geol. Aaeoc. (1870)
3a 2
t
678 MR. P. CHAPMAN 05 THP. BARGATE BEDS OP BURRET. [Nov. 1 894,
(though perhaps encroaching upon each) and possibly equivalent in
age to the Sandgate Btds.
Like the Sandgate Beds at Sand? ate and elsewhere, the Bargate
Beds are characterized hy much argillaceous material, which occurs
in them as numerous thin bands intercalated between the pebbly
and sandy deposits. Moreover, the Bargate Beds thin out and dis-
appear towards the area occupied by the Sandgate Beds.
Iu the Weald Memoir1 a reference is made by F. Drew to a
lane-section west of St. Martha's Chapel, near Guildford, noting
" apparently a representative of the Sandgate Beds." The beds
thus remarked upon consist of pebbly and sandy strata, with some
argillaceous material, and are without doubt referable to the top of
the Bargate series. They pass down with perfect sequence into the
Bargate Stone Beds.
At the base of the Folkestone Beds in some localities there are
well-marked bands of ochreous clay which, I am inclined to think,
are of the same age as the Bargate Beds. One section, in particular,
the first large exposure on the road from Dorking to Horsham,
shows clay seams, in some parts many inches in thickness, intcr-
htratified with the sand. In this clay numerous species of arenace-
ous foraminifera were found, to which reference will be made in the
sequel. But an examination of several samples of argillaceous
material from beds of undoubted Folkestone age gave no traces
of foraminifera, nor other organic remains. On the other hand,
a typical specimen of the Sandgate Beds from Sandgate, collected
by Mr. E. H. Schwarz, and kindly placed by him at my disposal,
contains a large assemblage both of foraminifera and ostracoda, with
many species equally characteristic of the Bargate Beds. This
specimen of Sandgate Clay also yielded many other organic particles,
such as siliceous replacements of spines of echinoderms, which had
hitherto been considered peculiar to the Bargate Stone and Pebble-
beds.
II. The Bargate Stone and Pebblb-beds in Littleton-lane
Quarry, near Guildford.
Detailed measurements of the beds in this quarry, about oie mile
8.W. of Guildford, previously given by C. J. A. Meyer2 differ
slightly from those now exposed in the quarry.
The following beds are seen in the section, in descending order : —
ft. in.
7. Snnd, with interbedded Bargate Stone 15 0
6. Brownish sand, with rolled (> sails 3 0
5. Whitish siliceous bed (with sponge-reinains) Gin. to 2 0
4. Pale sands, current-bedded 3 0
3. Laminated sanda and pebblj clays, passing into 0 9
2. Layer ot wbangular pebbles in clay (foraminil'era-bed) 0 3
1. Greenish sandy beds, wiih some eluy, and containing a Inrge pro-
ftortion of oolitic ironst one-grains ; coarsely current-bedded in the
ovrer half; and with carbonaceous bands and fucoid (?) marking* 3 0
Below this and down to the floor of quarry. Hythe Sands 12 U
1 Op. cii. p. 134, referring abso to p. 122. 2 Op. cit. p. II.
tale
Vol. 50.] MR. F. CHAPMAN 05 THR BAR© ATE BEDS QF 8TTRRKT, 679
Commencing above the ash-coloured sand (evidently of Hythe age,
which therefore does not here concern us), 12 feet of which is seen,
there is a bed of greenish sand, about 3 feet thick. In its lower
half this bed is coarsely current-bedded, and the lamination strongly
marked by carbonaceous bands, with argillaceous material, which
increases nearer the top. It contains many remanu- fossils and a
considerable proportion of oolitic ironstone-grains resembling those
of the iron-shot sand of Lincolnshire, with the difference, however,
that these Bargate grains appear somewhat flattened. There are
also occasional doubly-terminated crystals of quartz. Foraminifera
occur, but rarely, in the more argillaceous portions, amongst others
Textutaria pnthnga^ Keuss.
Next above is a band of variable thickness, usually about 3 inches,
of large and small subangular pebbles in clay, including clay -iron-
stone concretions, pieces of oolitic ironstone, fragments of lydite,
and waterworn pieces of ammonites and other fossils. From the
pale ochreous clay of this band a rich assemblage of mostly minute
foraminifera, ostracoda, and sponge-spicules was obtained. These
are not abundant, and are only found after careful search. For
the list of these and descriptions of new species, see p. 688.
Various minerals were obtained from the sand associated with this
clay ; and I am greatly indebted to Dr. W. Fraser Humo, F.G.S.,
for kindly supplying the following notes upon them : —
" The most numerous of the heavy minerals are undoubtedly the
zircons. These occur in two forms : (a) as crystals, (6) as rounded
grains. The largest crystal has a length of -178 mm. and a breadth
of 044 mm. The mineral possesses all the usual characters. The
rounded grains are far more numerous thau the crystals above
mentioned. These latter must have undergone considerable friction,
for, not only have perfect pebbles of zircon been formed, but these
have also been often fractured and sometimes apparently broken
completely across.
" HutiU. These are not so numerous as the zircons. Two different
kinds are observable. (1). Forms which at times show traces of a
prismatic habit, but are generally in a more or less rounded con-
dition. A typical specimen had a length of *1G5 mm. and a breadth
of -075 mm. (2). The second variety occurs in grains, of a clear
golden-yellow colour, and these are especially prominent owing to
their high refractivo index and strongly adamantine lustre
u Tourmaline. A few specimens of this mineral are present. They
are of distinct prismatic habit, bounded by rhombohedral faces,
these latter being generally only visible on one side.
" Kyanite. Cleavage-flakes of this mineral are by no means un-
common. These flakes are generally rectangular in shape, and
with an average length of * 134 mm., the cleavage being well-marked
parallel to the short axis. This mineral agrees with the kyanite
ligured from the Bagshot Sands of Hampstead Heath (Teall's
4 British Petrography,' pi. xliv. fig. 2).
" Quartz. Occurs in well-rounded grains, which are limpid, or at
most show minute lines due to the presence of gas-cavities.
Digitized by Google
680 MR. F. CHAPMA5 OK THE B ABO ATE BEDS 0? SUB BET. [Nov. 1 894,
** FtUpar. These grains are mostly kaolinized.
** A few ylauconite- grains also occur.
The minerals present here are of the same size as those from the
Bagshot Sands, and three times as large as those from the Chulk-
marl of the Isle of Wight."
Overlying the layer of clay-with-pebbles is a band of finely lami-
nated sand, with many small pebbles and occasional thin seams of
clay (also containing microzoa) ; the thickness of this band is about
9 inches. Together with the pebbles in clay below, it is conspicuous
in the quarry section, because of its greater resistance to weather-
ing. Above these comes in a bed of pale current-bedded sand,
averaging 3 feet in thickness.
This is overlain by a whitish siliceous bed of variable thickness,
consisting of sponge-remains, including fragments of Lit hist id
sponges, together with detached spicules of other types.
The higher beds in the Littleton Quarry consist of pebbly sand
with rolled fossil*, and sandy strata alternating with layers of com-
pact and generally ferruginous Bargatc limestone, amounting
altogether to about IS feet. The lower portion of these beds is
merely a loose calcareous grit, in the higher it is an exceedingly
compact limestone. The harder rock is of a dark reddish-brown
colour. On a fractured surface this rock shows numerous cleavage-
•urfaces of calcite, shell-fragments, and bright-green glaucouitic
particles.
Iu thin sections under the microscope the compact Bargate Stone
it) seen to consist of numerous rounded and subangular quartz-grains,
chalcedony, a few scattered grains of glauconite, many fragments of
shells such as Terebratultr and Exofj(jr<xy nearly all of which have
been silicified, also traces of polyzoa, portions of Lithistid and
llexactinellid sponges, nnd numerous spines aDd other parts of
echinoderms. These are all firmly cemented together by a ferrugino-
calcareous matrix. The molluscan shell-fragments are often perfo-
rated by apparently two distinct species of boring algse, one
consisting of fine interlacing filaments, and the other of coarser per-
forations with branches at short intervals. Moreover, in thin sections
of the limestone, teeth and bones of fish, etc., and occasionally the
tests of foraminifera can be distinguished. Amongst the latter
are Te-vtuUria trochu*, d'Orb., Gaudryina, sp^ and Lagena Uxvi*
(Mont.).
After dissolving this rock in weak hydrochloric acid, the residuum
amounts to bo per cent. The rock thus acted upon is, however,
still cemented together by ferruginous material; and this, when
removed by boiling in strong hydrochloric acid, is found to amount
to 12 per cent.
Some of the bodies in the siliceous residue resemble the spines of
certain species of Ifeniipedina and Cidarii from the Middle and
Upper Oolite, but the Bargate specimens are very minute.
The chalcedonized sponge-spicules are of a pale bluish-grey colour,
with a surface similar in appearance to ground-glass. There are
many examples of distortion amongst the casta of the axial canals of
Digitized by Google
Vol. 50.] MB. F. CHAPMAN 05 THE BARGATE BEDS OF SURREY. 681 .
spicules, which have been preserved in green chalcedony, generally
resembling the examples figured by Dr. Hinde.1
Among the casta of organisms preserved in green chalcedonic silica
are numerous pale-green threads, sinuous, branched, or bent, which
may be referred to the parasitic borings of minute plants in the
shell-fragments, etc. The perforations appear to have been filled
in with the chalcedony, the subsequent solution of the shell setting
free the delicate casts of the tubes. From the siliceous residue have
been obtained several fragments of shells which have themselves
been silicified, and, having lost their inner layer of shell-substance,
expose the interlacing filamentous casts still in place within the shell.
There are also some peculiar fasciculate and divergent masses of
pale green chalcedony, composed of cylindrical rods connected by
short bars or stolons. These objects are probably casts of polyzoa
(sec PI. XXXIII.fig.il).
One of the more remarkable specimens from the residue is what
appears to be a portion of a calcareous aljja allied to the Corallines
(see PI. XXXIII. fig. 9). It consists of three joints, each shorter
and more circular in section than in Corallina officinalis, but very
near that form. I submitted this specimen, with others of a more
doubtful nature and somewhat resembling the external form of
Lithothamnion (see PI. XXXIII. fig. 8), to Graf zu Solms-Laubach
of Strasburg, who remarks that " it is scarcely possible to be
absolutely certain of their affinities beyond placing these fragilo
fossils, at the best, in the AlgaB-group. Howover, I hold it very
probable that no. 4 represents a Corallina. The form of the joiuts
and the intermediate pieces agrees with it perfectly. No. 1 may
well bo one of the Diploporce" (see PI. XXXIII. fig. 10).
The arenaceous foraminifera in the residue are Uaplophragmium
emaciatum, Brady ; //. nonioninoides, Reuss ; H. dtprctsum, Jones ;
H. Humboldii, Reuss; U. irregulare (Rom.); Bulimina polystropha,
Reuss ; B. obliqua, d'Orbigny ; and B. pyrula, d'Orbigny.
III. The Baroatb Beds below St. Martha's Chapel (Chilworth).
The Bargate Stone and Pebble-beds are seen in, perhaps, greater
lithological variation (though not showing so great a development,
as westward and southward) in the lane leading to Great Halfpenny
Farm, on the west sido of St. Martha's Hill (Chilworth), than in any
other locality. The following are roughly approximate measure
meuts of the beds exposed in this lane : —
f Pebbly sand, underlying Folkestone Beds."] ft. in.
Bargate Limestone (much of it is oolitic).
Pebbly beds, with clay- seams. (Tbe \ 15 0
foraminifera were obtained from this
bed.) J
Soft sponge-bed, resting on bard sponge-
bed. (Just aboTe the Farm.) 8 0
Pebbly bed, resting on Hythe Sand with
ironstone 12 0
CO
M
<
•I
!!
{
Phil. Trans. Roy. Soc. vol. dxrri. (1886) p*. ii. pi. xlv. figs. 15a-«.
682 ME. J. CHAPMAN OH THE B ABO ATE BEDS OF 8UBBBT. [Nov. I 894,
At the lower end of the lane can he seen the yellow sand with
ironstone, evidently belonging to the Hythe series, following which
are pebbly beds about 12 feet thick, and with these the Bargate
series commenoes.
The Pebble-bed is replaced higher up by a hard siliceous rock, of
a whitish tint variegated with greenish-grey streaks. The rock
contains only a trace of calcareous matter, and consists almost
entirely of quartz-grains and sponge-spicules (the latter having the
axial canals usually filled in with mammillated chalcedony, though
occasionally with glauconite), with a few glauconite-grains (see fig. 1).
Fig. 1. — Thin section of siliceous rod' formed mainly of sponye-
spicuUs {teen in transverse section*), with ylauconite-yrains and
quartz. BanjaU series, Halfpenny Lane, ChUworlh. x2l.
A softer bed lies upon the hard rock containing sponge-spicules,
consisting apparently of brown sandy clay, and showing current-
1 edding when freshly broken down. This soft bed, upon washing
away the clay, yields a plentiful supply of sponge-epicules. These
spicule-beds amount to about 8 feet in thickness, and may be a
thicker development of the somewhat similar siliceous rock occurring
ai Littleton (see ante, p. 080). Dr. G. J. Hinde, V.P.G.S., has kindly
Vol. 50.] MB. F. CHAPMAN OH THE B AEG ATE BEDS OP 6UBBBT. 683
examined the spicules from this bed and also from that at Littleton,
and remarks upon them as follows: — "These beds with sponge-
remains are very similar to those in the same formation at Godalming,
Haslemere, Sevenoaks, and other places in Kent, Surrey, and Sussex.
Thin layers of the rock are mainly composed of detached spicules
of various forms, indiscriminately mingled together, and cemented
by a siliceous deposit one to the other. The spicules are usually
much fractured, and their original opal silica has been changed to
chalcedony and quartz. In places they are not cemented together,
and they can then be picked out from the sand-grains of the rock.
" The spicules belong to various forms of sponges. The styliform
and pin-shaped forms are like those of the existing mooactiuellid
genera AxintJla and Dirrhopalum (from St. Martha's). The most
numerous spicules are the trifid forms of the tetractinellid genus
Geodites, of which at least four species are present, O. robustus,
O. obtxisus, G. Gaudryi, Fischer, sp. (all from St. Martha's and
Littleton), and G. Carteri (from St. Martha's). There are also
caltrop spicules of Pachastrella (from St. Martha's and Littleton).
The Lithistida are represented by spicules of Mastosia (from St.
Martha's), Doryderma (from St. Marthas and Littleton), and
Khagadinia (from Littleton). There are likewise fragments of the
mesh and nodular masses of a hoxactinellid sponge (from Littleton J,
which has not yet been determined."
Above this sponge~depo»it, and on the west side of the road, is a
large exposure of pebbly beds with intercalated clay. seams, con-
taining many species of loramiuifera and a lew ostracoda.
Higher up the lane Bargate Stone begins to predominate, alter-
nating with pebble-beds and calcareous grit. In the siliceous
residue of the Bargate Stone from this spot Bulimina obtu$ay d'Orb.,
and Lagena globosa (Mont.), silicified, were found, and also two
speciroeus of a polyzoan, which have been determined by Dr. J. W.
Gregory, F.G.S., as a species of Ifeteropora.
The Margate Stone at this locality is extremely interesting, on
account of the occurrence of calcareous oolitic grains and brecciated
fragments of oolite in the rock (see fig. 2, p. 684). It seemed at
first probable that the oolitic grains might have been formed with
the rock in which they are found. Closer examination showed,
however, that they had been derived from an older rock, since
many exhibited signs of attrition, and had hard abrading particles
still adhering to or pressed into them. Moreover, some of the
grains were massed together, as they would appear in the original
rock ; and further, the quartz aud other grains in the rock are
perfectly free from calcareous deposit. These grains were evidently
derived from a calcareous oolitic rock of loose texture, resembling
some of the more friable ' roestones.' Other examples of Bargate
Stone were mainly composed of breccia, derived from a compact
oolitic limestone. One of the rock-specimens containing the
calcareous oolitic grains is of a pale reddish-brown colour, with
darker ferruginous streaks and veins ; the weathered surface of the
rock shows the oolitic grains quite distinctly. The rock is always
Digitized by Google
684 MR. F. CHAPMAN OW THK BAROATE BEDS OF SURREY. [XoV. 1 894
more or less gritty, the proportion of the oolitic grains in most
s|>cciniens being about one-third of the whole ; the other con-
stituents are the same aa in the normal Bargate Stone. The
oolitic grains under the microscope resemble those of the Bath and
other Oolites, and sometimes exhibit the same radially crystalline
structure.
Fig. 2. — Thin section of Bargate limestone with derived oolitic grains
and mucJi quartz. Halfpenny Lane, Chilworlh. x21.
At about the middle of tho series of exposures on the west side
of this lane a bed of gravel may be seen, overlying the Bargate Beds,
and containing large angular fragments of the Bargate limestone.
This gravel-bed occurs at a height of 30 feet above the Tillingbourne
stream, as stated by R. A. C. Godwin- Austen, and consists at this
spot of re-arrangcd Lower Greensand rock.1
From this gravel-bed I have collected many specimens of a
somewhat more purely calcareous oolitic rock. When examined
microscopically, this is seen to be composed of fragments of oolitic
limestone, forming a breccia, the pieces of limestone being very
1 'Along the saTeral branches of the valley [of the Guildford Gorge] the
proportion of materials from the Lower Greensand increases.' Godvria-
Austen, Quart. Jouru. Geol. Soc. toI. vii. (1851) p. 281.
le
Vol. 50.] 2IR. F. CHAPMAN ON THE BARQATE BEDS OF SURREY. 685
well preserved, and quartz-grains rarely occurring. Foraminifera,
such as Layena bxvis (Mont.) and Sodosaria radicula (Linn.), are
frequent in the fragments of oolite.
After a careful examination of those oolitic Bargate limestones
there remains no doubt whatever as to the detrital character of
the grains, especially as they occur associated with other rocks
evidently remnants of beds of the same age, possessing the brecciated
character. Moreover, the derived fragments and particles appear
to have been deposited gently, and quickly following their disin-
tegration, leaving the calcareous grains nearly as perfect as when
they formed part of the parent rock. The source of the derived
fragments was not, perhaps, very distant from the spot where these
beds are now found.
The occurrence of these detrital oolitic grains raises some question
as to the contemporaneity of the microscopic fossils found in the
clays of the Bargate series. Judging from the somewhat mixed
character of the facies, we probublv have, in the assemblage
collected, a few Jurassic forms (derivod), mingled with other species
indigenous to the Lower Greensand.
Prof. Judd, who has kindly examined my specimens, has called
my attention to the similarity of these rocks with those from the
Richmond well-boring, at a depth of between 1141' 6" and 1151' 6".
The material of the 10-ft. band at Richmond 1 is manifestly derived
from the disintegration of Great Oolite rocks, some of which were
found lower down in the boring. Since the 10-ft. baud contains
oolite grains and some ostracoda, which are common to this and the
Bargate Beds of Surrey, thore is good reason to suppose that we
have a thinned-out extension of the Bargate Beds represented in
the series beneath Richmond.
The sections of the Richmond rocks from the 10-ft. band all
more or less resemble those of the Bargate limestone, and especially
one slide, marked with the depth of 1151 ft. 6 in., which shows
great similarity to the Bargate oolitic rock, excepting that the colour
of the Richmond rock is grey-black instead of yellow or brown (see
iig. 3, p. G86).
It seems reasonable to conclude that the ridge of Great Oolite rocks
may have been situated immediately north of the Lower Greensand
outcrop in East Surrey, forming a subordinate axis, lying upon the
groat Palaeozoic axis which underlies London. To allow for this
proximity of the Jurassic Beds it would be necessary to beliove in
a sudden thinning-out in Surrey of the Wealden Beds, and also
of the members of the Lower Greensand older than the Bargate
Beds, to admit of the junction of the former with the Oolites ; or,
as Prof. Judd suggests, there is possibly a fault bringing up the
Oolitic rocks against the Lower Greensand.
Above the Bargate Stone Beds at St. Martha's Hill are some
pobble-beds passing upwards into true, reddish-coloured Folkestone
Sands with quartz-pebbles. Farther up the lane very good exposures
' * On the Nature and Relations of the Jurassic Deposits which underlie
London,' Quart. Journ. Geol. Soo. vol xl. (1884) p. 738.
Digitized by Google
686 MR. F. CHAPMAN Off THE BARGATE BEDS OF SURREY. [XoV. 1894,
of Folkestone Sands, with current-bedded strata and clay-galls, are
seen ; whilst higher still the Folkestone Sands are coloured variously
crimson, brown, yellow, and white.
Fig. 3. — Thin section of Neocomian limestone, with oolitic grains and
shell-j "ragments, from the depth of 1151' 6" t» the well-l>oring
at liirhmond, Surrey. For comparison with the specimens from
Chilworth. x 21.
In the Geol. Survey Memoir on the Weald (p. 122), the succession
of the beds in Halfpenny Lane is given as follows : —
Folkestone Beds ... Ferruginous sand.
San in; ate Beds \ ^ayy *«nd, with large pebbles and small patches of
I f uller's earth.
Brownish-grey sand, with ironstone.
Very coarse, dark sand, consistiug of grains of brown
ironstone.
IIytiie Beds J Brownish-grey sand.
Sand, with B trgale Stone and a few tbin layers of
fuller's earth. Some way lower down,
Ferruginous sands.
L Buff sands, not ferruginous.
The Bargate strata in this lane, so far as I have been able to
correlate them with the above data, commence with the beds
Vol. 50.] Mi:. P. CHAPMAN ON THE BARGATE BEDS OP SURREY. 687
marked * ferruginous sands (Hythe series),' and terminato most
probably in the clayey sands marked 4 Sandgute.'
I may mention incidentally the occurrence of pebbly beds
(current-bedded) in Sandy Lane (part of the Pilgrims' Way),
lending from Guildford t«» Complon. which are clearly the topMUDOfl
beds of the Bargate series, as, similarly with those underlying tho
Bargate Stone, they contain waterworn particles of organic origin.
Exposures of these beds are seen at the beginning of the lane at
the Guildford end, but where tho road rises they are overlain by
Folkestone Sands with Carstone ; and at Littleton Cross, where the
road again slopes down, the pebbly beds recur. At those places,
however, the beds with pebbles are seamed with very thin veins of
Carstone. Now this, at first sight, appears to conflict with the
idea of the Carstone representing the Folkestone Beds proper.
After many efforts to obtain a sight of the junction between tho
Folkestone Sands and the Bargate series (which latter, I consider,
are distinguished by the organic waterworn particles contained in
them), indications of a junction of the two series were found in tho
highest part of the lane lending from Sandy Lane to Compton
Common, where Carstone resembling that in the Folkestone Beds
was seen to run for severul feet below them into the Bargate Beds ;
and this is easily explained by the fact that the ferruginous veins
tend to till up all fissures in the beds beneath those which are their
source. The surface of the Bargate Beds at this place was much
eroded.
IV. CLAT-8EAM8 tx tbb Baroate Pebble-beds at Godalming.
In 1827 Dr. Fitton mentioned the occurrence of seams of ' tough
clay, like fuller's earth ' in the sand-beds below the Bargate Stone
beds at Hollo way Hill 1 ; and from these I have been able to collect
an interesting series of foraminifera (noted subsequently), all wry
minute, and mostly arenaceous forms. Many of the species are
common to both the Littleton and the St. Martha's faunas, from the
\\<->t and east of Guildford, No specimens of ostracoda WW met
with. The clay is of a cream-yellow colour, and occurs in seams
attaining sometimes as much as 3 or 4 inches in thickness.
V. Beds below tue Folkestone Skkies in the Horsham Boad,
south op Dorking.
The following are some details of the first large exposure of
Lower Greensand beds on the west side of tho Horsham Road,
within a mile of Dorking : — The lowest beds are ash-coloured sands ;
these are followed by sands with interst ratified seams of tough
day about 2£ feet in thickness. The elay on washing yielded a
remarkable series of very minute arenaceous foraminifera. The
strata with clay-seams are undoubtedly on the same horizon as the
Bargate Pebble-beds, and are succeeded by about 9 feet of sand
infiltrated and seamed with ferruginous material (Carstone).
1 Trans. Qeol. Soc. scr. 2, toI. iy. pt. ii. (1830) p. UC.
688 MB. F. CHAPMAN ON THE BARGATE BEDS OF SURREY. [Nov. 1894,
VI. OSTRACODA AND FoRAMIN TFERA OF THE LOWER GREENSAND.
The Lower Greensand strata of the S.E. of England are remark-
ahly poor in the actual tetts of forarainifera and other minute
fossils, the former being hitherto represented only by internal casts in
glauconite. Nevertheless, since glauconite-grains play so important
a part in the formation of these Greensand beds, foraminifera must
have existed in prodigious abundance at the time when these
deposits were laid down.
The Speeton Clay of Yorkshire, also the Hilsthon and other
Neocomian beds in North Germany and elsewhere, have already
yielded an abundant foraminiferal fauna.
It is interesting, therefore, to find the calcareous tests of fora-
minifera and the carapaces of ostracoda in the Bargato Beds of
Surrey. Whether this entire fauna was contemporaneous with the
beds in which it occurs has yet to be proved ; nevertheless, it is
noteworthy that among the species and varieties of foraminifera
found there are undoubted Lower Greensand forms.
VII. Ostracoda from the Bargate Pebble-beds of Littleton
and of St. Martha's Hill (Chilworth).
[These all belong to the Cytheridce.]
1. Cttherb vesiculosa, sp. nov. (PI. XXXIII. fig. 1 a, o, c.)
Valve quadrate, but rounded in front and bluntly pointed
posteriorly : the surfaco sloping away from the ventral margin to
the front and dorsal edges. Ventral face flat with the edges of the
valves forming a flanged bordor, which passes along the posterior
end of the valve. Dorsal edge short, locally swollen beyond the
anterior hinge and curving into the post orior edge behind. The
surface of the valve is irregularly swollen with rounded lumpy
prominences. There are four of these protuberances situated
towards the dorsal and central area, and a large and more pro-
minent one projecting from near the middle of the ventral edge of
the carapace ; the presence of this last process shows the species
to have a slight affinity towards the genus Cytheropteron. Length
-fa in. ('47 mm.).
This species somewhat resembles C. Cluthcey Brady, Crosskey, &
Robertson,1 and C. globulifera, Brady * ; but it differs from them
chiefly in the arrangement of the knobs.
Occurrence : one valve in clay of Bargate Pebble-beds, Littleton.
2. CTTHEREIS 0RNATIS81MA(ReU88).
Cytherina ornatixsimay Reuss, * Verstein. bohm. Kreidoform.,'
pt. ii. (1846) p. 104, pi. xxiv. figs. 12 & 18.
Cythereis omatissima^ Jones & Hinde, Mon. Cret. Entom.
Suppl., Pal. Soc. (1890) p. 21, pi. ii. figs. 1-7, 15, 16 ; pi. iv.
ti^s. 7, 8.
1 Mon. Poat-Tert. Entom., Pal. Soc. (1874) p. If 3, pi. liii. fijr§. 16. 17.
" Ibid. p. 153, pi. ix. figs. 18-20 i pi. xii. figs. 11, 12 ; pi. xv. figs. 19, i0.
Digitized by Google
Vol. SO.] MB. P. CHAPMAN ON THE BARS ATE BEDS OP SURREY. 689
There are some worn specimens of this species (from the clay of
the Bargate Pebble-beds at Juttleton) which, on careful examination,
show some faint reticulations of the test-surface, but are otherwise
more typical of the species than those mentioned below. It is a
common species in Upper Cretaceous strata.
Three valves only were found.
3. Cytherei8 orxatissima (Reuss), var. reticulata, Jones & Hinde.
Mon. Cret. Entom. Suppl., Pal. Soc. (1890) p. 24, pi. i. figs. 07,
68, 77 ; pi. iv. figs. 9-12.
The only specimen found is less than one-half the average
length of the specimens recorded in the Cretaceous Monograph,
this being only jfc in. (-42 mm.) in length. It is a characteristic
Upper Cretaceous variety.
From clay of Bargate Pebble-beds, Littleton.
4. Ctthereis Loxsdaleaxa, Jones.
Mon. Cret. Entom. Suppl., Pal. Soc. (1890) p. 27, pi. i. figs. 40-
42, 64-66.
This is a well-known form in Upper Chalk strata, and is also
recorded from the Upper Oolite of Ridgeway, Dorset.
One valve from clay of Bargate Pebble-beds, Littleton.
5. Cttheridea retorriba, Jonos & Shcrborn.
Proc. Bath. N. H. k Antiq. F.-Club, vol. vi. (1888) no. 3,
p. 260, pi. i. fig. 8a-c.
This species was first described from the FullerVEarth clay of
Midford, near Bath.
Four valves from clay of Bargate Pebble-beds, Littleton.
6. Ctthehibba subterporata, Jones.
Quart. Journ. Geol. Soc. vol. xl. (1S84) pp. 768 & 772,
pi. xxxiv. figs. 25, 26.
The Bargate specimens agree in all particulars with the descrip-
tion and figures of the above species, which was first found in the
junction-bed of tho Oolite and Neocomian (?), and also in the Great
Oolite, of the Richmond Well-boring in Surrey.
One valve from clay-seams in Bargate Pebble-beds, Littleton ;
and ono from the Pebble-beds in tho lane leading to Great Halfpenny
Farm, below St. Martha's Chapel, Chilworth.
7. Cttheridea rotubdata, Chapman & Sherborn.
Geol. Mag. (1893) p. 349, pi. xiv. fig. 11.
A solitary and fragmentary valve was found in the clay of the
Bargate series at Littleton, which possesses the peculiarly coarse
pittings on the surface of the test shown in the Gault specimen.
690 MB. P. CHAPMA1T OK THE BAR0ATK BEDS OF SURREY. [NOV. 1894,
8. CrrHERrDEA bicarixata, Jones & Sherborn.
Proc. Bath N. H. & Antiq. F.-Club, vol. vi. (1888) no. 3,
p. 270, pi. iv. fig. 5 a-c.
In this series there is only one specimen which can with some
certainty be referred to the above species ; this specimen, however,
is destitute of the tuberculations of the exterior of the hinge-line
such as are present on the specimens described from the Fuller's-
Earth clay of Midford, but probably not of specific value.
One valve from clay of Bargate Pebble-beds, Littleton.
9. Cttheridea BiCARiffATA, Jones & Sherborn, var. nod u lob a, nov.
(PL XXXIII. fig. 2 a, 6, c.)
This variety differs from the specific form, C. hicnrinata, in
having the two ventral carina? terminating posteriorly in a nodulous
prominence ; and it also has a median longitudinal, with a feebler
dorsal ridge ; these two ridges also end in a similar lumpy process in
the postero-dorsal region.
Six valves from clay-eeams in Bargate Pebble-beds, Littleton.
10. Cttheridea vellicata, sp. nov. (PL XXXIII. fig. 3 a, 6, c.)
Valve subovate, broad in front, tapering and blunt behind, with
a flanged posterior margin. Dorsal edge straight ; ventral margin
curved and steep, surmounted by a sharp keel running close to the
edge. The central area is occupied by a low ridge, and near the
postero-dorsal margin the surface is pinched up into a short keel
raised posteriorly into a blunt process. Length of valve -fa to in.
((H2 to 0-5 mm.).
Two valves from day-seams in Bargate Pebble-beds, Littleton.
11. Cttheridea fenestrata, sp. nov. (PL XXXIII. fig. 4.) '
Valve subovate, with a steep ventral margin sloping away to*
wards the front and back as in the above species C, vetticatay to
which, as to ridges and shape, it bears much affinity. The surface
is decorated on the dorsal side of the ventro-marginal ridge with
angular or square-shaped pittings arranged in two series. This
fenestrated surface of the test reminds one of Cytficropteron ferus-
tratuntj Brady 1 ; that species, however, has the fenestration con-
fined to one series of markings, besides being separated by generic
differences. Length of valve ^ in. (0*5 mm.).
One valve from clay of Bargate Pebble-beds, Littleton.
12. Cttheridea craticula, Jones & Sherborn.
Proc. Bath N. H. A Antiq. F.-Club, vol. vi. (1888) no. 3, p. 272,
pi. iv. figs. 9 a-c and 10 a-c.
The specimens originally described by the above authors were
from the Fuller's- Earth clay of Midford.
One valve from clay of Bargate Pebble-beds, Littleton.
> 'Challenger' Report, Zool., vol. i. (1880), G. S. Brady, Ortraooda, p. 130
pi. xxiiv. fig. 0, a-d.
Digitized by Google
Vol. 50.] KB. P. CHAPMAK ON THE B ABO ATE BEDS OF SURREY. 691
13. Ctthebibba bipaptxlata, sp. nov. (PI. XXXIII. fig. 5 a, 6, c.)
Valve suboblong ; the surface gently and almost equally convex.
The ventral edge is slightly steeper than tho dorsal edge. The
anterior margin rounded, with a flattened rim, narrow, but showing
a distinct fluting of the surface. The valve is decorated with some-
what irregular square or polygonal pittings. At the antero-dorsal
region aro situated two round and low papill®, placed close together.
Length of valve ^ in. (0*5 mm.).
One valve from olay of Bargate Pebble-beds, Littleton.
14. Cythbropterok concextricitm (Reuss).
Cytherina concentrica, Reuss, * Verstein. bohm. Kreidofo^n., pt. ii.
(1846) pp. 104 & 105, pi. xxiv. figs. 22 a-e.
CytJuropteron concentricum, Jones <fe Hinde, Hon. Cret. Entom.
Suppl., Pal. Soc. (1890) p. 31, pi. i. figs. 5-10, pi. iv. fig. 19.
This species has been recorded from Upper Cretaceous strata, from
the Neocomian of Haute Marne, and from the Upper Oolite (?) of
Dorset. The Bargate specimens still retain the delicate sculpturing
of the test-surface, and their excellent preservation leads me to
suppose that of these minute fossils some at least were living during
the deposition of these beds, and that, unlike the calcareous oolitic
grains found in the associated rocks, thoy may not have been derived
from older strata.
Two valves from clay-seams of Bargate Pebble-beds, Littleton ;
and two from Pebble-beds of Halfpenny Lane below St. Martha's
Hill, Chilworth.
15. Cythbroptebon cowcentricum (Reuss), var. virginea, Jones.
Cythere punctatula (non Rbmer), var. virginea, Jones, Mon. Cret.
Entom., Pal. Soc. (1849) p. 12, pi. i. fig. 2n.
Cytheropteron conccntricum, var. virginea, Jones & Hinde, Mon.
Cret. Entom. Suppl., Pal. Soc. (1890) p. 32, pi. i. figs. 14-17.
This variety is known from many Upper Cretaceous deposits
down to the Upper Greensand.
One fragmentary valve from clay of Pebble-beds, Littleton.
16. Cytheropteron subcokcbntricum (Jones).
Cythere gubconcentrica, Jones, Quart. Journ. Geol. Soc. vol. xL
(1884) p. 768, pi. xxxiv. figs. 28, 29.
This species was originally described from the Junction-bed of
the Oolite with tho Neocomian (?) from the Richmond Well-boring.
One valve from clay-seams of Pebble-beds, Littleton.
17. C ythbro pteron dbupacetth (Jones).
Cythere drupacea, Jones, Quart. Journ. Geol. Soc. vol. xl.
(1884) p. 772, pi. xxxiv. fig. 30.
This species was first described from the Great Oolite of the
Richmond Well-boring.
One valve from clay-seams of Pebble-beds, Littleton.
Q.J.G.S. No. 200. 3 b
1
p
692 HB. F. CHAPMAN OX THE B A BO ATE BEDS OP SURREY. [Nov. 1 894,
18. Cttheropteron laticristatum (Bosquet).
Cyihere Jaticrutata, Bosquet, Mem. Comm. Carte geol. Neerlande
vol. ii. (1854) p. 108, pi. vii. figs. 11 a-d.
This species appears to form a link between C. sphtnoides
(Reuss) and C. alatum (Bosquet), the postero-ventral wing of the
above species showing an intermediate stage of development.
Bosquet obtained his specimens from Upper Cretaceous and Tertiary
beds.
A very perfect and typical valve from clay of Pebble-beds,
Littleton.
19. Cttheropteron retict/losum, sp. nov. (PL XXXIII. fig. 6 a,
6, c.)
Valve subrhomboidal, with well-rounded anterior, and somewhat
oblique and slightly beaked posterior margin. The postero-ventral
process rises more anteriorly than in C. umbonatum (Will.) l, and is
less prominent. The area between this alar process and the antero-
dorsal margin is marked with interrupted surface-reticulations.
Length of valve -fa in. ('45 mm.).
One valve from clay of Pebble-beds, Littleton.
20. Cttheropteron costtjliperum, sp. nov. (PI. XXXIII. fig. 7 a,
0, c)
Side view of carapace, subovate, narrow, and rounded in front,
but bluntly pointed behind. Valve thickest at one-third from the
posterior end, sloping towards the antero-dorsal margins, and
highest in the middle of the dorsal edge. The ventral face is nearly
flat, hollowed slightly towards the ventral margins of the valves.
Dorsal margin bordered with a flange which continues less strongly
along the ventral margin. The ventral aspect shows the test-
surface striated longitudinally with about four low and narrow
costal ae on each valve ; and the surface of the carapace also has
several weak longitudinal ridges on each valve. The poetero-ventaral
swelling resembles that of C. concent ricum, var. virgineo, Jones.
Length of valve in. (0*45 mm.).
Two valves in conjunction, from clay-seams of Pebble-beds,
Littleton.
Of the twenty species and varieties just enumerated, seven are
apparently new ; nine have been previously noticed from Cretaceous
strata generally, whilst four are undoubted Jurassic forms.
» Mon. Cret Entom. fiuppl., Pal. Soc( 1890) p. 40, pi. i. 6gs. 21-26.
Digitized by Google
Vol 50.] MB. F. CHAPMAN OB THE B A HQ ATE BEDS OP SURREY. 693
■
VUI. Fobaminifera FROM the B a rg ate Beds, or their equivalents,
at Littleton, St. Martha's HiU (Chilworth), Godalming, and
Dorking.1
Family MILIOLID^.
Subfamily Miiiolisin^.
Milioliba, Williamson.
1. Miliolina agglutobabb (d'Orbigny).
Quinqueloculina agglutinans, d'Orbigny, * Foram. Cuba,' 1839,
p. 168, pi. xii. figs. 11-13.
Miliolina agghUinans, Brady, * Challenger' Rep. vol. ix. (1884)
p. 180, pi. viii. figs. 6, 7 ; Chapman, Journ. Roy. Micr. Soc. (1891)
p. 574, pi. ix. fig. 7.
Two specimens were met with, somewhat flatter on the broader
surfaces than in d'Orbigny's typical quinqueloculine form, but
closely resembling the variety found in the Gault (see last reference).
This occurrence in Neocomian strata is the earliest recorded appear-
ance of the species as a fossil.
From clay-seams in Bargate Beds at Holloway Hill, Godalming.
Subfamily Hauebiniit^.
Plabibpirina, Seguenza.
2. Plabispibiba obscura, sp. nov. (PI. XXXTV. fig. 1 a, 6, c.)
Test discoidal and nearly circular in outline ; compressed, slightly
convex on one face and concave on the other. The concave side in
the example found shows the first two or three whorls to be helicoid
and non-septate (?), while the last whorl is arrange 1 in the manner
of a Miliolina. Aperture a narrow slit placed terminally. Diameter
-fa in. (*45 mm.).
The genus Planispirina has hitherto been confined to the Tertiary
epoch, and is still represented in deep-sea deposits.
One specimen from clay-seams of Bargate Pebble-beds, Littleton.
Family LITUOLIDjE.
Subfamily Lituolibjs.
Haplophragmium, Reuss.
3. Haplophragmium agglutinabs (d'Orbigny).
Spirolina agglutinans, d'Orbigny, * Foram. Foss. Vienne," 1846,
p. 137, pi. vii. figs. 10-12.
1 The classification here employed is that given by the late H. B. Brady in
the ' Challenger ' Report on the Foraminifera, vol. ix. (1884), to which work I
am also indebted for general referenced.
3b 2
Digitized by Google
694 MB. F. CHAPMAN OK THE BARGATE BEDS OP SURREY. [NOV. 1S94,
Haplophragmium agglutinans, Brady, ' Challenger ' Eep. toL ix.
(1884) p. 301, pi. xxxii. figs. 19-26.
The example found is very characteristic, and exactly coincides
with d'Orbigny's figures of the Tertiary specimens ; it is easily dis-
tinguished from the other crosier-shaped species by the smallness
and compression of the spiral portion of the test. The occurrence
of this species in Neocomian beds helps to complete the record, from
its first appearance in Lower Carboniferous rocks, through all im-
portant fossiliferous strata to the present time.
One specimen from Bargate Beds, Holloway TTill.
4. Haplophragmtum Humboldti (Reuss).
Spirolina Humboldti, Reuss, Zeitschr. deutsch. geoL Oesellsch.
vol. iii. (1851) p. 65, pi. iii. figs. 17, 18.
Haplophragmium Humboldti, Reuss, Denkschr. Ak. Wiss. Wicn,
vol. xxv. (1865) p. 119, pi. i. figs. 1-4 ; Hantken, Jahrb. ungar.
geol. Anstalt, vol. iv. (1875) p. 11, pi. ii. figs. 3, 4.
This form is easily recognized by the cultration of the spiral portion
of the test, that feature distinguishing it from the closely-allied
form //. irregulare (Rbmer). It has previously been recorded from
various strata of Tertiary age.
One example in the siliceous residue from the Bargate limestone,
Littleton.
5. HaPLOPHBAGMITTM IRREGULARE (Romer).
Spirolina irregular*, Rbmer, 'Verst. nordd. Kreidegeb.' 1840,
p. 98, pi. xv. fig. 29.
Haplophragmium irregulare, Reuss, Sitzungsb. Ak. Wiss. Wien,
vol. xl. (1860) p. 219, pi. x. fig. 9, pL xL fig. 1.
This species has been noted from various Cretaceous beds in
North Germany and Bohemia.
One specimen in siliceous residue from Bargate limestone and
three in clay of Bargate series, Littleton.
6. Haplophragmium poliacbum, Brady.
H. foliaceum, Brady, ♦Challenger' Rep. vol. ix. (1884) p. 304,
pi. xxxiii. figs. 20-25.
The specimens met with in the Bargate Beds resemble the recent
specimens of Dr. Brady in the extremo transparency of the thin
arenaceous test ; but they are probably arrested forms of the species,
since the Neocomian specimens do not exhibit the crosier-shaped
form caused by the linear arrangement of the later chambers.
Two specimens from clay of Bargate series, Holloway Hill.
7. Haplophbagmixjm emaoiatttm, Brady.
H emaciatum, Brady, ' Challenger ' Rep. vol. ix. (1884) p. 305,
pi. xxxiii. figs. 26-28.
A single specimen was found which evidently must be referred
to the above species, since the coiling of the chambers is evolute ;
Digitized by Google
Vol. 50. J MR. F. CHAPMAN ON THE BABQATfi BED8 OP SURREY. 695
one face of the test is fractured, showing the spiral of chambers
filled up completely with glauconite.
From siliceous residue of Bargate limestone, Littleton.
8. Haplophragmium acutidorsatum, Hantken.
H. acutidorsatum, Hantken, Magyar Foldt. Tarsulat, vol. iv.
(1868) p. 82, pi. i. fig. 1 ; and Jahrb. ungar. geol. Anstalt, vol. iv.
(1875) p. 12, pi. i. fig. 1.
The specimen from the Bargate series is quite typical in form,
but not in size: Hantken's speoimens being from 1 to 2*5 mm.
in diameter, while the former is only 0*22 mm. The originally
described specimens were from the Hungarian Tertiaries.
From clay of Bargate Pebble-beds, Littleton.
9. Haplophragmium neocomiajtum, sp. nov. (PI. XXX1T. fig. 2 a, 6.)
Test arenaceous, thin, planospiral, and involute. The septation
is obscure, but usually about nine chambers appear on the test-
surface ; the last chamber is sometimes slightly produced at the
outer angle. The surface of the test, which is nearly always of a
brown colour, is undulated. Aperture an arched slit situated at
the base of the terminal chamber. Diameter -fa in. (0-5 mm.).
This species is nearly related to II. fontinense,1 but the latter
species is arranged on an evolute plan.
From clay-seams of Bargate Beds, Littleton (four specimens) ;
from clay of Pebble-beds, Halfpenny Lane, Chil worth (one speci-
men) ; and from clay-seams in Bargate Beds, Holloway Hill (thirteen
specimens).
10. Haplophragmium xontortnoides, Reuss.
27. nonioninoida, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xlvi. (1862) p. 30, pi. i. fig. 8.
Some of the specimens from the Bargate series of the above
species closely approach IT. canariense (A. d'Orbigny's Nonionina
eanariensis)2 in form — especially those which have the test con-
stricted at the sutures and the chambers well inflated. Dr. Reuss's
specimens of H, nonioninoides were obtained from the * Flammen-
mergel ' and the * Minimus-Thon * of North Germany, beds which
are nearly the equivalent of the Gault in this country. It is also
a well-known foraminifer in the English Gault.
One specimen from siliceous residue of Bargate limestone, and
nine from clay of Pebble-beds, Littleton ; one from Pebble-beds of
Halfpenny Lane, Chilworth; and three from Bargate Beds, Holloway
Hill.
11. Haplophragmium depressum, Jones.
H. deprtssum, Jones, Quart. Journ. Geol. Soc. vol. xl. (1884)
p. 765, pi. xxxiv. fig. 2.
This species waa described by Prof. T. Rupert Jones from the
3 D'Orbigny, « Foram. lies OanarieB,' 1839, p. 138, pi. ii. fig* 33, 34.
Digitized by Google
€96 MR. F. CHAPMAK ON THE BARQATE BEDS OF SURREY. [NoV. 1894,
Neocomian (10 ft.) band of the Richmond Well-boring. The con-
cavity of the sides of the teat and its general compression are
characters sufficient to enable one to place many specimens of
]Jai>loj>hrar/mium from the Bargate series with this species.
One specimen from siliceous residuo of Bargate limestone and
two from clay of Pebble-beds, Littleton ; one from clay in Bargate
Bods, Holloway Hill ; and ten from beds below Folkestone series,
Horsham Road-cutting, Dorking.
Subfamily Trochammihin^.
Ammodiscus, Re uas.
12. Ammodiscus lkcertus (d'Orbigny).
Ojvrculitia incerta, d'Orbigny, 1 Foram. Cuba,' 1839, p. 71, pL vi.
figs. 16, 17.
Trochammina squamata, var. incerta, Parker & Jones, in
Carpenter, ' Introd. Foram.' App. 1802, p. 312.
Ammodiscus incertus, Brady, 'Challenger' Rep. voL ix. (1854)
p. 330, pi. xxxviii. figs. 1-3.
This species, which is common in most of the fossiliferous strata
from the Carboniferous to the present time, is well represented in
the Bargate rocks. These particular specimens vary greatly in out-
line, some being elliptical — instead of circular as in the typical
examples, and in this variation bearing resemblance to specimens
from the Gault Clay of this country. The test of the Bargate
specimens is in nearly all cases white, with the exception of a few
which are ruddy-brown in colour as in recent specimens.
From Bargate Pebble-beds, Littleton (eight specimens); from
clay of Bargate Beds, Holloway Hill (two) : and from bods below
the Folkestone series, Horsham Road-cutting, Dorking (three).
13. Ammodiscus gordialis (Jones and Parker).
Trochammina squamata-yordiaUs, Jones & Parker, Quart. Journ.
Geol. Soc. vol. xvi. (1860) p. 304.
T. yordialis, Carpenter, 4 Introd. Foram.' 1862, p. 141, pi. xi.
fig. 4.
Ammodiscus yordialis, Brady, ' Challenger' Rep. vol. ix. (1884)
p. 333, pi. xxxiii. figs. 7-9.
Tho Bargate specimens of the above species arc precisely similar
to other fossil and recent examples. The occurrence of A. gordialis
as a fossil dates from the Carboniferous period.
From Pebble-beds, Littleton (three specimens) ; from Bargate
Beds, Holloway Hill (one); and from beds below Folkestone series,
Horsham Road, Dorking (one).
14. Ammodiscus charoides (Jones & Parker).
Trochammina squamata-charoides, Jones & Parker, Quart. Journ.
Oeol. Soo. vol. xvi. (I860) p. 304. '
Vol. 50.] MB. P. CHAPMAN OH THE BAROATB BEDS OF SURREY. 697
T. charoicUs, Carpenter, 'Introd. Foram.' 1862, p. 141, pi. xi.
fig. 3.
Ammodiseus charoides, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 334, pi. xxxviii. figs. 10-16.
The Bargate specimens of the above species are rather minute,
measuring only from to J5 inch (0*25 to 0*3 mm.). The test is
quite white and has a perfectly smooth surface. A, charoides is
known from the Swiss Jurassic, and also from Tertiary and recent
deposits.
In the Bargate series it was found at Littleton only, in the clay
of the Pebble-beds (three specimens).
15. Ammodiscus pleubotomabioidbs, sp. nov. (PI. XXXIV. fig. 3 r»,
Test coarsely arenaceous, consisting of a helicoid spiral of four
whorls. The basal aspect of the test is excavate, and the separate
whorls are not distinctly seen. The opposite face of the test is
convex. Diameter of test J% inch (0*63 mm.) ; height T^ inch
(0-21 mm.).
This species is perhaps more nearly allied to A. yordialis than to
any other species of Ammodiseus ; especially since some examples
of the latter species have an irregular helicoid method of growth,
with the flat side more or less excavate.1 It also appears to be
isomorphous with the perforate form Spirillina obconica, Brady.3
One specimen from Bargate Pebble-beds, Littleton.
Tkochammdta, Parker and Jones.
16. Trochammina squamata, Jones & Parker, var. ltkbata, nov.
(PI. XXXIV. fig. 4 a, b, c.)
Test finely arenaceous, whitish and translucent. This variety
differs from the type-form T. gqtiamata ' in having the margins of
the chambers composed of transparent test-material. The test
has usually fewer convolutions than the type form, there being, as
a rule, two, or at the most three, while there are in T. squamata
as many as four. Diameter of the test to ^ inch (0*1 to
0-5 mm.).
From Pebble-beds, Littleton (five specimens) ; from clay of Bar-
gate Beds, Holloway Hill (six) ; and from beds below Folkestone
series, Horsham Road, Dorking (thirty-eight).
1 See Burrows, Sherbora, & Bailey, Journ. Roy. Micr. Soo. 1800, p. 552,
pi. Tiii. fig. 7 ; also Chapman, Journ. Boy. Micr." Soc. 1892, p. 327, pi. vi.
fig. 13.
3 Quart. Journ. Micr. 8ei. vol. xix. n. s. (1879) p. 279, pL viii. fig. 27 a, b.
Also 4 Challenger * Rep. toI. ix. (1884) p. 630, pi. lxxxr. figs. 6, 7.
3 Jones & Parker, Quart. Journ* Geol. Soc. vol. xvi. (I860) p. 304;
Carpenter, « Introd. Foram.' 1862, p. 141, pi. xi. fig. 1 ; Brady, 4 Challenger'
Rep. vol ix. (1884) p. 337, pi. xli. fig. 3a-c.
Digitized by Google
698 US. P. CHAPMAN ON THE B ABO ATE BEDS OF 5TJRBEX. [Nov. 1894,
Family TEXTULARIIILE.
Subfamily Tbitclariisa
Textularia, Defrance.
17. Textularia sagittxtla, Defrance.
T. sagittula, Defrance, Diet. Sci. Nat. vol. xxxii. (1824) p. 177,
vol. liii. p. 344 ; Atlas Conch, pi. xiii. fig. 5 ; Brady, * Challenger '
Rep. vol. ix. (1884) p. 361, pi. xlii. figs. 17, 18.
To this species must be assigned some Bargate specimens which
are compressed, cuneiform, or sagittate, and with more or less sharp
edges. These Neocomian specimens are, however, about one-third
the usual size, their average length being only inch (0*25 mm.).
T. sagiitula has hitherto made its first appearance in Upper
Cretaceous beds (Gault and Chalk), and is fairly common in all
newer deposits up to the present time.
Eight specimens from beds below Folkestone series in Horsham
Road-cutting, Dorking.
18. Textularia oramen, d'Orbigny.
T. gramen, d'Orbigny, 4 Foram. Foss. Yienne,' 1846, p. 248, pi. xv.
figs. 4, 6 ; Brady, * Challenger ' Rep. vol. ix. (1884) p. 365, pi. xliii.
figs. 9, 10.
This species occurs in the Bargate series, but is smaller than
usual ; in some cases the specimens closely approach T. ylobulosa,
Ehrenberg,1 in the inflation of the last two chambers.
From Febble-b«ds, Littleton (six specimens) ; in Bargate Beds,
Holloway Hill (two) ; and in beds below Folkestone series, Horsham
Road, Dorking (two).
19. Textularia prolong a, Reuss.
T. pralonga, Reuss, 4 Vorstein. bohm. Kreid.' pt i. (1845) p. 39,
pi. xii. fig. 14.
This species is represented from the Bargate series by one speci-
men from the Littleton Pebble-beds, and one from the beds below
the Folkestone series, Horsham Road, Dorking.
20. Textularia minuta, Berthelin.
T. minuta, Berthelin, Mem. Soc. geol. France, ser. 3, vol. i.
(1880) no. 6, p. 26 a; Chapman, Journ. Roy. Micr. Soc. 1892,
p. 327, pL vi. fig. 15.
The examples found are similar to those from the Folkestone
Gault both in size and form.
Five specimens from Bargate Pebble-beds, Littleton.
4 Abhand. Ak. Wiss. Berlin (1838), 1839, p. 135 (no. 60), pi. iv. fig. (3.
* This species i« the same as that figured by Reuss under the name of
T. pygmaa, Siteungsb. Ak. Wise. Wien, vol. xlvi. (1862) p. 80, pL ix. fig 11 ;
the specifio term pygnuta having been previously used for another Textularian
typo by A. d'Orbigny, it was afterwards renamed by Berthelin to avoid con-
Digitized by Google
Vol. 50.] MR. F. CHAPMAN ON THE BARQATE BEDS OP 8URRKY. 699
21. Textularia aoolutinans, d'Orbigny.
T. agglutinins, d'Orbigny, * Foram. Cuba,' 1839, p. 136, pi. i.
figs. 17, 18, 32-34 ; Chapman, Journ. Roy. Micr. Soc. 1892, p. 329,
pLvi. fig. 21.
The specimens from the Bargate series are very small, but bear
all the characters of the above species. It is interesting to note
this form as occurring in the Neocomian beds, having been lately
found in the Gault, though previously unknown from beds older
than the Tertiaries.
Three specimens from Pebble-beds, Littleton.
22. Textularia trochus, d'Orbigny.
T. trochus, d'Orbigny, Mem. Soc. ge'oL France, vol. iv. (1840)
p. 45, pi. iv. figs. 25, 26.
This species is already known from Cretaceous and Tertiary strata.
The only isolated specimen found in the Bargate series is a replace-
ment of the test in green ohalcedonic silica ; but several examples
of the same species have been noted in thin sections of Bargate
limestone. All the specimens were from Littleton.
23. Textularia turris, d'Orbigny.
T. turrit^ d'Orbigny, Mem. Soc. geol. France, vol. iv. (1840)
p. 46, pi. iv. figs. 27, 28.
This species is also known from Cretaceous and newer strata.
Two rather small specimens from Bargate Pebble-beds, Littleton,
measuring -fa inch (0-3 mm.) in length.
Vkrneuilina, d'Orbigny.
24. Verneuilina triquetra (Munster).
Textularia triquetra, Munster (in Homer's paper), Neuee Jahrb.
1838, p. 384, pi. iii. fig. 19.
Verneuilina triquetra, Brady, 4 Challenger ' Rep. vol. ix. (1884)
p. 383, pi. xlvii. figs. 18-20.
The Bargate specimens are very minute, being only -Xr inch
(0*35 mm.) in length. The specimens which were found in the Gault 1
measured about -fa inch (0*75 mm.), whilst Dr. Brady's measure-
ments of the same species are ^ to | inch (1 to 4 mm.) in length.
Four specimens from Bargate Pebble-beds, Littleton.
Trttaxia, Reuse.
25. Tritaxia tricarinata, Reuse.
Tr. tricarinata, Reuss, 'Verstein. bohm. Kreid.' pt. i. (1845)
p. 39, pi. viii. fig. 60 ; Reuss, Sitzungsb. Akad. Wiss. Wien, vol. xl.
(I860) p. 228, pL xii. figs. 1, 2; Chapman, Journ. Roy. Mior. Soc.
1892, p. 749, pi. xi. fig. 1.
This species, like the preceding, is characteristic of Cretaceous
1 Chapman, Journ. Boy. Mior. Soc. 1892, p. 329, pL vi. fig. 24 a, b.
Digitized by Google
700 MR- F. CHAPMAN OH THB BAB9ATB BEDS OP SURKBT. [NOV. 1 894,
strata. The Bargate specimens resemble those from the Gault in
that they possess an inflated terminal chamber, probably indicative
of age.
From Bargate Pebble-beds, Littleton (two specimens) ; and from
Halfpenny Lane, Chilworth (one).
Spiroplecta, Ehrenberg.
26. Spiroplbcta ahhbctens (Parker & Jones).
Textularia annectens, Parker & Jones, Ann. & Mag. Nat. Hist,
ser. 3, vol. xi. (1863) p. 92, woodcut, fig. 1.
SpiropUcta annectens, Brady, 'Challenger' Rep. vol. ix. (1884)
p. 376, pi. xlv. figs. 22, 23.
Some minute specimens of the above species, which is not un-
common in the Gault, occur in the Bargate series.
Two specimens from clay of Pebble-beds, Littleton ; and one from
clay of Bargate Beds, Holloway Hill.
27. Spiroplbcta bipormis (Parker & Jones).
Textularia agglutinant, var. biformis, Parker & Jones, Phil.
Trans. Boy. Soc. vol. civ. (1865) p. 370, pi. xv. figs. 23, 24.
SpiropUcta biformi*, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 376, pi. xlv. figs. 25-27.
The specimens of the above species from the Bargate series are
quite typical, having a coarsely arenaceous test, inflated chambers,
and rounded edges to the test. It is known from Upper Cretaceous
strata, etc.
Two specimens from Pebble-beds, Littleton ; two from clay of
Bargate Beds, Holloway Hill ; and five from beds below Folkestone
series, Horsham Road, Dorking.
Gaudrtiha, d'Orbigny.
28. Gaudrtiha pupoides, d'Orbigny.
G. pupoidts, d'Orbigny, Mem. Soc. geol. France, voL iv. (1840)
p. 44, pi. iv. figs. 22-24.
This species is frequent in Cretaceous strata.
Six typical examples were found in the Bargate series in the
Pebble-bods at Littleton, and two in the Bargate Beds at Holloway
Hill.
29. Gaubryiba baccata, Schwager.
O. baccata, Schwager, 4 Novara' Exped., geol. Theil, vol. iL (1866)
p. 200, pi. iv. fig. 12.
Three specimens from Bargate Beds, Holloway Hill, Godalming.
Digitized by Google
Vol. 50.] MB. F. CHAPMAN OR THE BAHGATE BEDS OP SURREY. 701
30. Gaudryjka filiform is, Berthelin.
G. jWformis, Berthelin, Mem. 8oc. geol. France, se"r. 3, vol. i.
(1880) no. 5, p. 25, pi. i. fig. 8.
This form was first described from the Gault of France, and has
subsequently been found in the English Gault.
One specimen from clay of Bargate Pebble-beds, Littleton.
Valvuliwa, d'Orbigny.
31. Vaxvtjliha conica, Parker & Jones.
V. triangularis,, var. conica, Parker <fc Jones, Phil. Trans. Roy.
Soo. vol. civ. (1865) p. 406, pi. xv. fig. 27.
V. conica, Brady, 'Challenger' Kep. vol. ix. (1884) p. 392,
pi. xlix. figs. 15, 16.
This species has been recorded from the Gault, and is also found
living at the present time.
One specimen from Bargate Beds, Holloway Hill.
32. Valvtjluta fusca (Williamson).
Eotalina fusca, Williamson, 4 Rec. For. Gt. Br.' 1858, p. 55, pi. v.
figs. 114, 115.
ValvuUna fusca, Brady, 1 Challenger ' Rep. vol. ix. (1884) p. 392,
pi. xlix. figs. 13, 14.
V. fusca has been found in the Gault, otherwise, like the preced-
ing species, it was known only from recent gatherings.
Three specimens from Bargate Pebble-beds, Littleton ; they are
not attached, but they plainly show their adherent character.
Bulimina, d'Orbigny.
33. BUUMTNA POLTSTROPHA, RcUSS. (PI. XXXIV. fig. 5.)
B. polystropha, Reuss, ' Verstein. bohm. Kreid.' pt. ii. (1845)
p. 109, pi. xxiv. fig. 53 a, b.
This species is perhaps one of the most interesting and important
of the foraminifera found in the Bargate series, since it throws
some light on the actual position of the specimens found by Reuss
in the Chalk of Bohemia. The Bargate specimens are somewhat
coarsely arenaceous, with a rough surface, triserial, and they have
the aboral end distinctly twisted ns in Reuss's figure ; moreover,
the aperture is clearly that of a Bulimina, being comma-shaped.
The figure given by Reuss (loc. cit.) is misleading, since the
surface of the test is depicted as being smooth, although in the
description of the species it is stated to be rough. The form re-
ferred to in the Monographs of the Gault Foraminifera of Montcley 1
and Folkestone 3 as Bulimina polystropha, Ras., I am now inclined
1 Berthelin, Mem. Soc. geol. France, ser. 3, voL i. (1880) no. 5, p. 80, pL ii.
fig. 3 a, 6.
a Chapman, Jouro. Boy. Micr. Soc. 1892, p. 766, pL xii. fig. 11.
702 MB. P. CHAPMAN ON THE BABQATB BEDS OP 8UKBBI. [Nov. 1 894,
to refer to Vemmilina pygmaa, Egger, sp., the latter being a form
which has the test of fine arenaceous material, quite hyaline in
appearance, and with a Textularian aperture. It is worth noting
that an isomorphous and recent form which Dr. Brady connects
with Keuss's species, but which, because of the Textularian aperture,
is placed in the genus Verneuilina, lives in shallow water to the
depth of 50 fathoms, its place being apparently occupied below that
depth by tho larger and stronger variety Verneuilina propinqua,
Brady.
The Bargate specimens of Bulimina polystropha measure from
^ to -fr inch (0-42 to 0-56 mm.) in length, while Dr. Brady's
specimens were ^ inch (0#63 mm.) long.
One specimen from siliceous residue of Bargate limestone, Little-
ton ; three from clay in Pebble- beds, Littleton ; ono from Bargate
Beds, Holloway Hill ; and one from beds below Folkestone series,
Horsham Road, Dorking.
34. Bulimina pupoibes, d'Orbigny.
B. pupoides, d'Orbigny, 'Foram. Foss. Vienne,' 1846, p. 185,
pi. xi. figs. 11, 12 ; Brady, * Challenger ' Rep. vol. ix. (1884) p. 400,
pi. 1. tig. 15 a, 6.
Five specimens from Pebble-bods, Littleton ; and one from beds
below Folkestone series, Horsham Road, Dorking.
35. Bulimina appdos, d'Orbigny.
B. affinis, d'Orbigny, 4 Foram. Cuba,' 1839, p. 109, pi. ii. figs. 25, 26.
Five typically formed, but small, examples were found in the
Pebble-beds, Littleton; and two in the Bargate Beds, Holloway
Hill.
36. Bulimina ovata, d'Orbigny.
B. ovata, d'Orbigny, * Foram. Foss. Vienne,' 1846, p. 185, pi. xi.
figs. 13, 14.
Three specimens from Pebble-beds, Littleton ; and one from
Bargate Beds, Holloway Hill.
37. Bulimina ptbula, d'Orbigny.
B. caudigera, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826), p. 270,
no. 16: Modele no. 68.
B. pyrula, d'Orbigny, * Foram. Foss. Vienne,' 1846, p. 184, pL xi.
figs. 9, 10.
The occurrence of this species in the Bargate Beds is interesting,
since it has been before recorded by Messrs. Parker and Jones from
beds (probably Liassic) at Chellaston, and it also occurs in the Gault.
One specimen from siliceous residue of Bargate limestone, Little-
ton ; and five from Pebble-beds, Littleton.
38. Bulimina obliqua, d'Orbigny.
B. obliqua, d'Orbigny, Mom. Soc. geoL France, vol. iv. (1840)
Digitized by Google
Vol. 50.] MB. F. CHAPMAN OK THE BAEGATK BEDS OF SURREY. 703
p. 40, pi. iv. figs. 7, 8 ; Chapman, Journ. Roy. Micr. 800. 1892,
p. 754, pL xii. fig. 3.
The specimens from tho Bargato Bods closely resemble the Gault
specimens.
One specimen from siliceous residue of Bargate limestone, Little-
ton ; two from Bargate Pebble-bode, Littleton ; one from Pebble-
beds, Halfpenny Lane ; and one from Bargate Beds, Holloway Hill.
39. Bulimtna Prbbli, ReUBS.
B. Presli, Reuse, * Verstein. bohm. .Kreid/ pt. i. (1845) p. 39,
pi. xiii. fig. 72.
This species is the largest of the Bulitninat from the Bargate
series, the specimens measuring ^ inch (0*63 mm.) in length.
This form is also found in the Gault of Folkestone (where it attains
the same size) and in other Cretaceous strata.
Two specimens from Bargate Pebble-beds, Littleton.
40. Bflduna OBTT8A, d'Orbigny.
B. obtusa, d'Orbigny, Mem. 80c. geol. France, vol. iv. (1840)
p. 39, pi. iv. figs. 5, 6.
This species, which is already known from the Gault and Chalk,
was found in the Pebble-beds, Littleton (three specimens) ; in the
siliceous residue of the Bargate Stone, Halfpenny Lane, Chil worth
(one) ; and in the Bargate Beds, Holloway Hill (one).
41. Buijmina Mubchisoniaha, d'Orbigny.
B. Murchisoniana, d'Orbigny, Mem. See. geol. France, vol. iv.
(1840) p. 41, pL iv. figs. 15, 16.
Two specimens from the Pebble-beds, Littleton.
42. Bulimina BRKvis, d'Orbigny.
B. brevu, d'Orbigny, Mem. 80c. geol. France, vol. [iv. (1840)
p. 41, pi. iv. figs. 13, 14.
This species was previously known as peculiar to Cretaceous
strata, occurring in the Gault and Chalk.
Nine specimens from Bargate Pebble-beds, Littleton ; one from
Pebble-beds, Halfpenny Lane ; one from Bargate Beds, Holloway
Hill ; and two from beds below Folkestone series, Horsham Road,
Dorking.
Viroultna, d'Orbigny.
43. VlBOCLDIA 8UB8QU AMOS A , EggCr.
V. subsquamosa, Egger, Neues Jahrb. 1857, p. 295, pi. xii.
figs. 19-21.
Previously recorded from Miocene and later deposits, this form
occurs in the Bargate Pebble-beds, Littleton (three specimens) ; and
in the Bargate Beds, Holloway Hill (one).
704 MR. P. CHAPMAN ON THE BARGATE BEDS OP SURREY. [NOV. 1894,
44. ViBQULmA subdepressa, Brady.
V. tubdeprtsm, Brady, 1 Challenger' Rep. vol. ix. (1884) p. 416,
pi. Hi. figs. 14-17.
One specimen, agreeing minutely with Dr. Brady's description of
a form affecting deep waters (1850-2350 fathoms) of the South
Pacific and South Atlantic Oceans, was found in the Bargate
Pebble-beds at Littleton.
Bolivia, d'Orbigny.
45. BoLIVIKA TEXTILARI0IDE8, ReU88.
B. textilarioidet, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xlvi. (1862) p. 81, pi. x. fig. 1.
Three specimens of this species, which is a well-known Gault
fossil, were found in the Bargate Pebble-beds at Littleton. They
measure from T^ to ^ inch (0-21 to 0-42 mm.) in length.
46. (?) Bolivia a dilatata, Reuss.
B. dilatata, Reuss, Dcnkschr. Akad. Wissensch. Wien, vol. i.
(1849) p. 381, pi. xlviii. fig. 15.
The two specimens found in the Bargate Pebble-beds at Littleton
are doubtfully referred to the above species, since instead of having
narrow and oblique chambers they have them broad and less in-
clined, as in B. tcxtilarioides. The general form of the test is,
however, comparable with Reuss's species.
Subfamily Casbidulinin-e.
Cassidulina, d'Orbigny.
47. Cassidulina subglobosa, Brady.
O. suhjlolma, Brady, Quart. Journ. Micr. Sci. vol. xxi. (1881)
n. s. p. 60 ; and ' Challenger ' Rep. vol. ix. (1884) p. 430, pi. liv.
fig. 17 a-c.
This interesting species has been previously recorded as a fossil
from the London Clay.1 Dr. Brady's specimens wore found in deep-
sea deposits at from 435 to 2750 fathoms.
Two specimens from the Pebble-beds, Littleton.
Ehrenbergdta, Reuss.
48. Ehrenberoina pupa (d'Orbigny). (PI. XXXIV. fig. 6 a, 6.)
Cassidulina jmjxt, d'Orbigny, 'Forara. Amer. Merid.' 1839, p. 57,
pi. vii. figs. 21-23.
Ehrenbergina pupa, Brady, 'Challenger' Rep. vol. ix. (1884)
p. 433, pi. lv. fig. 1 a, b ; pi. cxiii. fig. 10 a-c.
The specimens of the above species which were found in the
1 Sherborn & Chapman, Journ. Roy. Micr. 8oc. aer. 2, vol. ri. (1886)
p. 744, pi. xri. fig. 2 a, 6.
Vol. 50.] MR. F. CHAPMA* ON THE BARGATE BEDS OF SURREY. 705
Bargate Beds are not quite typical, but the difference is so slight
that it appears to be worth no varietal distinction. In Ehrcnbcr-
gina pupa the conformation of the test can be compared with a
Bulimina which has been flattened or stretched out in its widest
direction, the two lateral margins folded together, and the test
coiled vertically upon itself. The Bargate specimens exhibit the
longitudinal folding, but not to so marked an extent as in recent
examples. The species has not been before recorded in the fossil
condition.
Three specimens from the Pebble-beds, Littleton.
Family LAGENID^E.
Subfamily Lagbnik e.
Lagena, Walker & Boys.
49. Lagena globosa (Montagu).
Vemiiculum globosum, Montagu, 4 Test. Brit.' 1803, p. 523.
Entosolenia globosa, Parker & Jones, Ann. & Mag. Nat. Hist,
ser. 2, vol. xix. (1857) p. 278, pi. xi. figs. 25-29.
Lagtna globosa, Brady, 4 Challenger ' Rep. vol. ix. (1884) p. 452,
pi. lvi. figs. 1-3.
L. globosa is known from beds of Jurassic age upwards. It is
represented in the present series by six specimens, one of which is
pyriform, whilst the remaining five are subglobular. Four were
found in the Pebble-beds, Littleton, one (silicified) in the siliceous
residue of Bargate limestone from Halfpenny Lane, and one in the
Pebble-beds, same locality.
50. Lagena apiculata, Reuss.
Oolina apiculata, Reuss, Haidinger's Naturw. Abhandl. vol. iv.
(1850) p. 22, pi. i. fig. 1.
Lagena apicuUta, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xlvi. (1862) p. 319, pi. i. figs. 4-8, 10, 11.
L. ai>iadata, Brady, •Challenger' Rep. vol. ix. (1884) p. 453,
pi. lvi. figs. 4, 15-18.
This species is known from the Lias and many fossiliferous beds
of later date. It is common in the English Gault, and is also found
in Cretaceous deposits of North Germany of about the same age.
The four specimens from the Pebble-beds, Littleton, are all sub-
globose in form.
51. Lagena lsvis (Montagu).
Vtrmiculum Ictve, Montagu, * Test. Brit.' 1803, p. 324.
Lagena Icevis, Williamson, Ann. & Mag. Nat. Hist. ser. 2, vol. i.
(1848) p. 12, pi. i. figs. 1, 2; Brady, * Challenger' Rep. vol. ix.
(1884) p. 455, pi. lvi. figs. 7-14, 30.
An example of this foraminifer was seen in a thin section of
Digitized by Google
706 MB. F. CHAPMAN ON TUB BARBATE BEDS OF SURREY. [Nov. 1 894,
Bargate limestone from Littleton ; it is distinguished by its lengthened
tubular (ectosolenian) neck.
52. Lagena ACCTIC08TA, Reuse.
L. acuticosta, Reu&s, Sitzungsb. Akad. Wissensch. Wien, voL xliv.
(1861) p. 305, pi. i. fig. 4; Brady, * Challenger ' Rep. vol. ix.
(1884) p. 464, pi lviii. fig. 21 ; Chapman, Journ. Roy. Micr. Soc.
1893, p. 583, pi. viii. fig. 12 a, 6.
This species has been recorded as a fossil from the Gault of
Folkestone, the Maestricht Chalk, and the 8eptarien-Thon of
Pietzpuhl.
A very neat but typical specimen comes from the Bargate
Pebble-beds, Littleton.
53. Lagena Meyeriana, sp. nov. (PI. XXXI V. fig. 7 a, 6.)
Test subpyriform and somewhat compressed on two Bides. The
flattened faces each bear a loop-shaped carina, which is slightly
bent inward towards the aboral end of the test. The oral end
gives a subroctangular section, with the carina? disposed diagonallv
and ending a little short of the aperture. The aperture is circular,
but the neck is entosolenian. Length y^0 inch (0-21 mm.) ; longer
diameter ^0 inch (0-14 mm.) ; shorter diameter yJUj inch (0-1 mm.).
I have much pleasure in naming this elegant little species after
Mr. C. J. A. Meyer, F.G.S., who has contributed so largely to our
knowledge of the Lower Greensand strata, and especially of tho
Bargate Pebble- and Stone-beds.
One specimen from clay of Pebble-beds, Littleton.
Subfamily IT 09 OS abii n JL
Nodosaria, Lamarck.
54. Nodosaria (Dentalina) brevis, d'Orbigny.
Dentalina brevi*, d'Orbigny, ■ Foram. Fobs. Vienne,' 1846, p. 49,
pi. ii. figs. 9, 10.
This form has been recorded as a fossil from the Upper Lias of
Northampton,1 from the Red Chalk of Specton,' and from many
Tertiary beds.
One specimen from Bargate Pebble-beds, Littleton.
55. Nodosaria (Dentalina) Roemeri, Neugeboren.
Dentalina Koemeri, Neugeboren, Denkschr. Akad. Wissensch.
Wien, vol arii. (1856) p. 82, pi. ii. figs. 13-17.
This form is characterized by a short, stout test, with obliquely-set
chambers.
Two small-sized specimens from the Pebble-beds, Littleton.
1 W. D. Crick & 0. D. Sherborn, Journ. Northampt. Nat. Hist. Soc
toI. Tii. (1892) p. 69, pi. ii fles. 6, 7.
J Burrows, Sherborn. & Bailey, Journ. Boy. Micr. Soc. 1890, p. 557,
pi. ix. fig. 28.
Vol. SO.] MR. P. CI1APMAN ON THE BARBATE BEDS OP SURREY. 707
56. Nodosaria (Dextalina) xiphtoides, Reuss.
N. (D.) xiphioide* , Reuss, Sitzungsb. Akad. Wiasensch. Wien,
vol. xlvi. (1862) p. 43, pi. iii. fig. 1.
This species has been hitherto apparently restricted to the Gault
formation, since it whs found in the ^/intmt/«-Thon of North
Germany, in the Gault of Montcley, and at Folkestone.
One specimen with three chambers, from the Pebble-beds,
Littleton.
57. Nodosaria (Dentalina) l[Mbata, d'Orbigny.
X. limbata, d'Orbigny, Mem. Soc. geol. Franco, vol. iv. (1840)
p. 12, pi. i. fig. 1.
JV. limbata is a characteristic Chalk fossil, and has also been found
in the lied Chalk of Hunstanton.1
The three fragmentary examples found in the Pebble-beds at
Littleton are not quite so deeply constricted between the chambers
as in the figures given by d'Orbigny, but they exhibit the test-
thickening between the segments.
58. Nodosaria (Dextalina) Fontannesi, Borthelin.
Dentaliaa Fontaanesi, Bcrthelin, Mem. Soc. geol. France, se"r. ii,
vol. i. (1SS0) no. 5, p. 42, pi. ii. fig. 14.
This form has been described from the French and English Gault.
Two specimens from the Pebble-beds, Littleton.
59. Nodosarta (De.ntalina) obsccra, Reuss.
N. oltscura, Reuss, ' Verstein. bohm. Kreid.' pt. i. (1845) p. 26,
pi. xiii. figs. 7-9.
A familiar Cretaceous species, two specimons of which, differing
greatly in eize (and the larger one fragmentary), were found in the
Bargato Pebble-beds at Littleton.
60. Nodosaria tex u i cost a, Reuss.
jV. tenuieosta, Reuss, ' Verstein. bohm. Kreid.' pt. i. (1845) p. 25,
pi. xiii. figs. 5, 6.
A Cretaceous form between N. rajihanvs (Linn.) and N. raphani-
stnon (Liun.), with thin platy costa). It has been found in beds
equivalent in age to the Lower Grecnsand in Germany, also in the
French and English Onult, and in the Pinner-Merge! of Bohemia.
Two spocimens from Pebble-beds, Littleton.
61. Nodosarta prismatic. \ , Reuss.
JV'. prisnvttira, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xl.
(I860) p. 180, pi. ii. fig. 2.
JV. pri&matku is already known from beds of Lower Greensand
1 Burrows. Sherbom. & Bailer, Journ. Roy. Micr. oc. 189(), p. f)57, pi. ix.
fig. 23.
Q. J. G. S. No. 200. 3 o
4 J
I
708 MB. P. CHAPMAN OK THE BARGATE BEDS OP SURREY. [Nov. 1 894,
age in North Germany, from the Gault, and other later Cretaceous
deposits.
One fragmentary specimen from Pebble-beds, Halfpenny Lane,
below St. Martha's Chapel, Chilworth.
Lingulina, d'Orbigny.
<32. Lingulina carinata, d'Orbigny.
L. carinata, d'Orbigny, Ann. Sci. Nat. vol. viL (1826) p. 257,
no. 1 : Modt-le no. 26.
This has been recorded from various fossiliferous deposits,
including the Lias, and many Cretaceous and Tertiary beds.
The form figured from the Red Chalk of Hunstanton 1 appears to
be a variety intermediate between L. carinata, d'Orbigny, and
L. nodomria, Reuss, and would therefore be represented by the form
L. bohemica, Reuss.
L. carinata from the Bargate series resembles the figures of recent
specimens in that they have a short and rather broad (ovate) test,
tending to become acuminate at the aboral end, with sharp sides,
and low and numerous chambers.
Three specimens from the Pebble-beds, Littleton.
63. LiNGULINA BE3O0HNATA, RoUSS.
L. semiornata, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 91, pi. xii. fig. 11.
The above species was described by Reuss from the Folkestone
Gault, and it is well distributed through that formation ; moreover,
it appears to be almost entirely restricted to those beds, since its
only occurrence out of the Gault (besides the present record), so far
as I am aware, has been noticed by myself, whilst examining some
Chalk-marl from East Wear Bay, Folkestone, for a comparative study
of the Cretaceous rhizopoda. The specimens from the Bargate
series are slightly worn on their surfaces, but the semistriate
character of the test is distinctly seen when moistened.
Two specimens from the Pebble-beds, Littleton.
64. Lino u lin a semiornata, Reuss, var. crassa, nov. (PI. XXXIV.
fig. 8 o, b.)
Associated with the specimens of L. semiornata from the Bargate
Pebble-bed, was a Lingulina singularly distinct from tho typical
form with a fragile and slender test, since it possesses a heavily-
made test, and much broader than that of the type form. The
semistriate character is also present in this example. The length
of the test is ^ inch (0-75 mm.), tho breadth -fa inch (0-3 mm.)
One specimen from the Pebble-beds, Littleton.
1 Burrows, Sherborn, & Bailey, Journ. Roy. Micr. 8oc. 1890, p. 658, pi. x.
fig. 3 o, b.
Digitized by Google
Vol. 50.] MB. P. CHAPMAN ON THR BABGATB BEDS OP 8UBBET. 709
Fbondiculabia, Defrance.
65. Fbondiculabia bbiz-spobmis, Bornemann. (PI. XXXIV.
fig. 9 a, 6).
F. brizaformis, Bornemann, * Liasformation von Gottingen,'
1854, p. 36, pi. iii. figs. 17 a-d, 18 cr-c, 20 a, b.
A perfect example of this very elegant Liassic species was found
in the Bargate Pebble-beds at Littleton. The Lower Greensand
specimen is much neater than those figured by Bornemann (loc. ext.).
Maboi5ULtna, d'Orbigny.
66. Mabginulina linearis, Keu8S.
M. linearis, Reuss, Sitzungsb. Akad. Wissensoh. Wien, vol. xlvi.
<1862) p. 60, pL v. fig. 15.
31. linearis has been found in the Minimus-Thon of North
Germany, and in the Gault of Folkestone.
Oue specimen from the Pebble-beds, Littleton.
67. Mabginulina debilis, Berthelin.
M. debilis, Berthelin, Mem. Soc. geoL France, ser. 3, vol. i.
(1880) no. 5, p. 35, pi. iii. fig. 28.
One fragmentary specimen of this Gault species, from the Pebble-
beds, Littleton.
68. Mabginulina compbessa, d'Orbigny.
M. compressa, d'Orbigny, Mem. Soc. geol. France, vol. iv. (1840)
p. 17, pL i. figs. 18, 19; Reuss, *Verstein. bbhm. Kreid.' pt. i.
(1845) p. 29, pi. xiii. fig, 33.
One example of this Upper Cretaceous species, from the Pebble-
beds, Littleton.
69. Mabginulina .equivoca, Reuss.
M. (equivoca, Reuss, Sitzungsb. Akad. Wissensoh. Wien, vol. xlvi.
(1862) p. 60, pi. v. fig. 17.
One specimen of this form, previously recorded from the Minimus-
Thon of North Germany and from the French and English Gault,
was found in the Pebble-beds, Littleton.
70. Mabginulina Jonesi, Reuss.
M. Jonesi, Reuss, Sitzungsb. Akad. Wissensch. Wieo, vol. xlvi.
(1862) p. 61, pl.v. fig. 19.
This species has previously been recorded from beds of Neocomian
age (Upper Hils-Thon) of North Germany, and from the Gault of
France and England.
One specimen from the Pebble-beds, Littleton, and three in
the Pebble-beds at Halfpenny Lane, below St. Martha's Chapel,
Chilworth.
3o2
Digitized by Google
710 KB. ». CHAPMAN ON THE BABGATS BEDS OP SUBSET. [Nov. 1894,
71. Mabginuxina stbiatocostata, Reuse.
M. striatoco»tata, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xlvi. (1862) p. 62, pi. vi. fig. 2.
Two specimens of a Marginulina, with well-rounded aboral ends,
occurred in the Pebble-beds, Littleton, and must be referred to the
above species. M. striatoemtata has been found in the Upper Hlls
formation near Brunswick.
72. Mabginulina Muniebi, Berthelin.
M. Munieri, Berthelin, Mem. Soc. geol. France, ser. 3, vol i.
(1880) no. 5, p. 33, pi. i. figs. 19 a, 6.
This species has been described from the French Gault, and it is
also found at Folkestone.
Two specimens from the Pebble-beds, Littleton.
Vaginalis a, d'Orbigny.
73. Vaginulina leoumen (Linne).
Nautilus Ugumtn, Linne, * Syst. Nat.' 10th ed. (1758) p. 711,
no. 248 ; 12th ed. (1707) p. 1164, no. 288.
Vaginulina legumen, Brady, * Challenger' Rep. vol. ix. (1884)
p. 530, pi. lxvi. figs. 13-15. '
This species makes its first appearance in beds of Liassic age, and
is also generally distributed through nearly all later fossiliferous
deposits.
Two specimens from the Pebble-beds, Littleton.
74. Vaginulina arguta, Reuss.
V. arguta, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xl.
(1860) p. 202, pi. viii. fig. 4 ; vol. xlvi. (1862) p. 47, pi. iii. fig. 13.
This species is known from the Gault and Neocomian beds of
North Germany, and from the Gault of England and France.
One specimen from the Pebble-beds, Littleton.
75. Vaginulina spabsicostata, Reuss.
V. sjwrsicostata, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xlvi. (1S62) p. 50, pi. iv. fig. 4.
This species was found by Reuss in the Upper Hils-Thon of North
Germany.
The Bargate specimens are both damaged, and the more perfect
one agrees with Reuss's figure, with the exception that the latter
has the primordial chamber quite minute, whilst in the former it is
large and inflated. This difference may, however, be referred to a
* dimorphic ' relation between the two examples of the same species,
Reuss's specimen belonging to form B, whilst the Bargate specimen
exemplifies form A of MM. Munier-Chalraas and Schluinberger.1
Two fragmentary specimens from the Pebble-beds, Littleton.
1 Cotnptce-rendus Acad. Sci. Paris, rol. xcvi. (1883) pp. 8C>2, lf>98 ; Ann. 4
Mag. Nat. Hut. »er. f>, vol. xi. (18^SS) p. 380. & toI. xii. (1883) p. 67.
Digitized by Google
VoL SO.] MR. P. CHAPMAN ON THE BARGATB BEDS OP SUBSET. 711
76. Vaginulina nbocomiana, sp. nov. (PI. XXXIV. figs. 10 a, 6,
11.)
Test elongate ; slightly inourved in the first third of the test, and
recurved from a third above the commencement to the terminal
chamber. Segments numerous (eight in the full-grown individual) ;
the primordial chamber circular and more or less inflated, following
which the chambers are compressed and typically Yaginuline ; but
later on they assume the character of Marginuline segments, since
they are subtriangular in section, and terminate in a marginal neck.
Towards the back of the test on each side is a marginal keel, whilst
the back itself is also sharp. Sutures well marked, especially in the
larger and well-grown examples, which have the later chambers
tending to separate one from the other. Surface of the test longi-
tudinally striated with fine cost®. Length of largest specimen
■fa inch (0*9 mm.).1
Seven specimens, some fragmentary, from the Pebble-beds,
Littleton.
Cbistellabia, Lamarck.
77. Cbistellabia tbicabinella, Reuss.
C. tricarinetta, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 68, pi. vii. fig. 9.
C. tiruncana, G umbel, Abhandl. bayer. Akad. Wissensch. 2te Gl.
vol. x. (1868) p. 639, pi. i. fig. 68 a, b.
C. tricarinella, Brady, 'Challenger' Rep. vol. ix. (1884) p. 540,
pi. lxviii. figs. 3, 4.
O. tricarirulla is somewhat closely related to certain forms of
Vaginulina, but although the sides of the test are nearly fiat, it
commences with a distinct spiral growth. Reuss records this species
from the Hils.Thon and Speeton Clay of North Germany, and
Giimbel obtained his specimens from the Nummulitic marl of the
.Kressenberg, Bavaria. Its occurrence as a recent form is noted
by Dr. Brady from the Pacific, at depths of from 95-155 fathoms.
One specimen from the Pebble-beds, Littleton, and one from the
Pebble-beds, Halfpenny Lane, Chilworth.
78. Cbistellabia vestita, Berthelin.
C. vettita, Berthelin, Mem. Soc. geol. France, se'r. 3, vol. i. (1880)
no. 5, p. 55, pi. iii. fig. 22.
This pretty costate form is allied to C. italica (Defrance) in out-
line, but diners in the ornamentation of the test. It was described
from the Gault of France, and is also known from Folkestone.*
Two specimens from the Pebble-beds, Littleton.
1 Several of Terquem's Jurassic species are somewhat related to this form,
especially Marginulina hybrida(' Foram. du Lias/ 5me Mem., Metz, 1866, p. 490,
pL xvii. figs. 9 a, b, c), except that the latter has a Cristellarian commencement.
Also Vaainulina linearis (Montagu) resembles the above form, but differs
materially in having no extreme form of Marginuline neck.
* Author's MS.
712 MR. F. CHAP* AH OK THE BARGATE BEDS OF 8CRBET. [Nov. 1 894,
79. Cristellaria italica (Defrance).
Saracenaria italica, Defrance, Diet. Sci. Nat. vol. xxxii. (1824)
p. 177, vol. xlvii. p. 344 ; Atlas Conch, pi. xiii. fig. 6.
Cristellaria (Saracenaria) italica, d'Orbigny, Ann. Sci. Nat.
vol. vii. (1826) p. 293, no. 26 : Modeles uoa. 19 & 85.
C. italica, Brady, * Challenger ' Rep. vol. ix. (1884) p. 544,
pi. lxviii. figs. 17, 18, 20-23.
This form is known from Upper Cretaceous and Tertiary strata,
and as a recent form it is never found in very deep water.
One specimen from the Pebble-beds, Littleton.
80. Cristellabia bulcifeba, Reuss.
C. sulcifera, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvL
(1862) p. 74, pL viii. fig. 9.
Previously known from the Minimttt-Thon of North Germany
And from the Gault at Folkestone (Reuss) ; three specimens were
found in the Bargato Pebble-beds, Littleton.
81. Cbibtellaria com plan at a, Reuss.
C. com plana ta, Reuss, * Verstein. bohm. Kreid.' pt. i. (1845) p. 33T
pi. xiii. fig. 54; Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 92, pi. xii. fig. 13.
This species has been recorded from the Chalk of Bohemia, and
from the Gault of Folkestone and Montcley.
One specimen from the Pebble-beds, Littleton.
82. Cribtellaria parallela, Reuss.
C. parallela, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 67, pi. vii. figs. 1, 2.
This species is known from the Upper Hils-Thon of North
Germany and from the Gault of France.
One specimen from the Pebble-beds, Littleton.
83. Cristellaria Schloenbaciii, Reuss.
C. Schloenbachi, Reuss, Sitzungsb. Akad. Wissensch. WienT
vol. xlvi. (1862) p. 65, pi. vi. figs. 14, 15.
This species was described by Reuss from the Upper Hils-Thon
and Specton Clay of North Germany. Dr. Brady records it from
deep-sea deposits at depths varying from 155 to 435 fathoms.
Two specimens from the Pebble- beds, Littleton, and one from the
Pebble-beds, Halfponny Lane, near St. Martha's Chapel, Chilworth.
84. Cristellaria crepidula (Fichtel & Moll).
Nautilus crepidula, F. & M., * Test. Micr.' 1803, p. 107, pi. xix.
tigs. g-i.
Cristellaria crepidula, d'Orbigny, 'Foram. Cuba/ 1839, p. 64,
pi. viii. figs. 17, 18; Brady, * Challenger' Rep. vol. ix. (1884)
p. 542, pi. lxvii. figs. 17, 19, 20, pi. lxviii. figs. 1, 2.
This species has been obtained from beds as old as the lias, and
Digitized by Google
Vol. 50.] ME. F. CHAPMAN ON TUB B ABO ATE BEDS OP 8TTBRBT. 713
it occurs in nearly all subsequently formed fossiliferous deposits, as
well as in those of tho present time. The recent forms are found
in shallow, to moderately doep, waters.
Four typical specimens from tho Pebble-beds, Littleton.
85. Cristellaria grata, Reuss.
C. ((rata, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 70, pi. Tii. fig. 4.
This form was originally described from the Neocomian bods of
North Germany.
One specimen from tho Pebble-beda, Littleton.
86. Cristellaria ctmboides, d'Orbigny.
C. qtmboides, d'Orbigny, * Foram. Foss. Vienne/ 1846, p. 85, pi. iii.
figs. 30, 31.
One very fine and perfect example of this Tertiary species was
found in the Bargate Pebble-beds, Littleton.
87. Cristellaria laevigata, Reuss.
C. hrvi</ata, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1802) p." 02, pi. xii. fig. 14.
Reuss described this species from the Gault at Folkestone.
Three specimens from tho Pebble-beds, Littleton.
88. Cristellaria acctaurictlaris (Fichtel & Moll).
Xuittilus acutauricularis, F. & M., 'Test. Micr.' 1803, p. 102,
pi. xviii. figs. <j-i.
C. (tcutauriciihtrit, Rrady, 'Challenger' Rep. vol. ix. (1884)
p. 543, pi. cxiv. fig. 17 a, b.
Five specimens of this form, which occurs in various Secondary
and Tertiary deposits, were found in the Pebble-beds, Littleton.
89. Cristellaria Bkonni (Roraer).
Plannlaria Broitni, Romcr, ' Verstcin. nordd. Kreidcgeb/
1840 41, p. 07, pi. xv. fig. 14.
Cristellaria Brunni, Reuss, Sitzungsb. Akad. Wissensch. Wion,
vol. xlvi. (1802) p. 70, pi. vii. fig. 13.
This species has been found in tho Spceton Clay of North
Germany.
One specimen from the Pebble-beds, Littleton, and one from the
Pebble-beds, Halfpenny Lane, Chil worth.
90. Cristellaria oligostegia, Reuss.
C. oliyostetfia, Heuss, Sitzungsb. Akad. Wissensch. Wion, vol. xl.
(1860) p. 213, pi. viii. fig. 8; and vol. xlvi. (1862) p. 03, pi. xiii.
fig- 2.
This species was found by Reuss in the detrital sand of the
Westphalian Chalk, and also in the Gault of Folkestone.
One young specimen from the Pebble-beds, Halfpenny Lane,
Chilworth.
M
714 MB. F. CHAPMAN OW THE BAROATB BEDS OF SURREY. [Nov. 1 894,
91. Cristellaria rotflata (Lamarck).
LentumlxUs rotukita, Lamarck, Ann. Museum, vol. v. (1804)
p. 188, no. 3 ; Tab. Encyd. Meth. pi. cccclxvi. fig. 5.
Cristellaria rotidata, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 547, pi. lxix. fig. 13 a, b.
This species makes its first appearance in beds of Ordovician age
(Ulrich), and is common in most fossiliferous deposits up to the
present time. As a recent form it occurs in shallow-water deposits
und also in those down to a depth of 2200 fathoms (Brady).
Twelve specimens from the Pebble-beds, Littleton, and two from
the Pebble-beds, Halfpenny Lane.
92. Cristellaria cultrata (Montfort).
Bobulus cultrattu, Montfort, 'Conchyl. System/ vol i. (1808)
p. 214, 54s genre.
Cristdlaria cultrata, Brady, * Challenger* Rep. vol. ix. (1884)
p. 650, pi. lxx. figs. 4-6.
This form is first met with in beds of Liassic age, and it is also
fairly common in Cretaceous and Tertiary strata. As a recent
organism it affects deeper water than the preceding species.
Nine specimens from the Pebble-beds, Littleton, and two from
the Pebble-beds, Halfpenny Lane.
93. Cristellaria oibba, d'Orbigny.
C.gibba, d'Orbigny, 'Foram. Cuba,' 1839, p. 63, pi. vii. figs. 20, 21.
C. jndchella, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) p. 71, pi. viii. fig. 1.
The fossil forms recorded by Reuss were from the Upper Hils-Thon
and the Minimus-Thon of North Germany. As a recent form it is
found in soundings down to 500 fathoms (Brady).
Eight specimens from the Pebble-beds, Littleton, and one from
the Pebble-beds in Halfpenny Lane.
94. Cristellaria convergers, Bornemann.
C. convergent, Bornemann, Zeitschr. deutsch. geol. Gesellsch.
vol. vii. (1855) p. 327, pi. xiii. figs. 16, 17.
As a fossil the above species has been recorded from Tertiary
strata. It is also found as a recent form, usually in deep water.
Two specimens from the Pebble-beds, Littleton.
95. Cristellaria promintjla, Reuss.
C. jtrominula, Reuss, Zeitschr. deutsch. geol. Gesellsch. vol. vii.
(1855) p. 271, pi. ix. fig. 3 a, 6.
One specimen of this Cretaceous species was found in tho Pebble-
bods, Littleton.
96. Cristellaria meoalopolitana (Reuss).
Robulina megalopolitana, Reuss, Zeitschr. deutsch. geol. Gesellsch.
vol. vii. ( 1855) p. 272, pi. ix. fig. 5 a, 6.
Digitized by Google
Vol. 50.] MB. F. CHAPMAN ON THE B IRQ ATE BEDS OF SURREY. 715
C. subalata, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi.
(1862) pp. 76 & 93, pi. viii. fig. 10, pi. ix. fig. 1.
C. megalopolitana, Sherborn & Chapman, Journ. Roy. Micr. Soc.
ser. 2, vol. vi. (1886) p. 755, pi. xv. fig. 30 a, 6.
This form has been found in Neocomian, Upper Cretaceous, and
Tertiary strata. It is separated from the foregoing species by the
inflation of the test, especially in the umbilical region, and by the
perfect cristation of the peripheral edge. C. tubalata was described
by Reuss from the Speeton Clay and Minimut-Thon of North
Germany, and from the Gault of Folkestone ; it has also been
found in the Gault of Montcley, France (Berthelin).
One specimen from the Pebble-beds, Littleton.
57. Cbistkl labia vabians, Bornemann.
C. variant, Bornemann, 4 Liasformation von Giittingen,' 1854,
p. 41, pi. iv. figs. 32-34; Tate & Blake (1876), p. 466, pi. xvii.
fig. 27; Crick & Sherborn, Journ. Northampt. Nat. Hist. Soc.
vol. vi. (1891) p. 213, pi. i. fig. 30, & vol. vii. (1892) p. 70, pi. ii.
figs. 15, 16.
Two specimens of this Liassic form were found in the Pebble-
beds, Littloton.
Subfamily Polymokphinina
Poltmobphina, d'Orbigny.
98. Poltmobphjna amtgdaloidbs, Reuss.
P. amygdaloidts, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. xviii. (1855) p. 250, pi. viii. fig. 84.
A very typical, though small, specimen of the above was found
in the Pebble-beds, Littleton.
99. Poltmobphina sobobia, Reuss, var. cuspidata, Brady.
P. sororia, var. cuspidata, Brady, * Challenger* Rep. vol. ix.
(1884) p. 563, pi. lxxi. figs. 17-19, pi. lxxii. fig. 4.
This variety was found in recent soundings by Dr. Brady, from
depths between 808 and 1443 fathoms.
One specimen from the Pebble-beds, Littleton.
100. Poltmobphina gutta, d'Orbigny.
P. (Pyrulina) gutta, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826)
p. 267, no. 28, p. 12, figs. 5, 6 : Modele no. 30.
This form has been recorded under the name of Pyrulina obtuta,
by Reuss, 1 from the Hils-Thon (Neocomian) of North Germany ;
and it is also met with in other fossiliferous deposits of later date.
Three specimens from the Pebble-beds, Littleton.
1 Sitiungsb. Akad. Wiwenach. Wien, toI. xlri. pt. i. (1862) p. 79, pi. ix. fig. 9.
716 KB. F. CHAPMAN OX THE BARGATE BEDS OF 8UBRBT. [NOV. 1894,
101. Polymobphtjta commit* is, d'Orbigny.
P. (Guttulina) communit, d'Orbigny, Ann. Sci. Nat. vol. vii.
(1826) p. 226, no. 15, pi. xii. figs. 1-4 : Modele no. 62.
This shallow-water form is represented here by one specimen
from the Pebble-beds, Littleton.
102. Polymorphic a compbessa, d'Orbigny.
P. compress, d'Orbigny, 4 Foram. Foss. Vienne/ 1846, p. 243,
pi. xii. figs. 32-34.
This species is also a shallow-water form, and makes its earliest
appearance as a fossil in the Lias of France and England.
Two specimens from the Pebble-beds, Littleton.
103. Polymobfhima obloxga, Williamson.
P. lactm, var. oblonya, Williamson, * Rec. For. Gr. Brit/ 1858,
p. 71, pi. vi. figs. 149, 149 a.
This species is easily distinguished from P. awjusta, Egger,1 by
its compressed outline in transverse section. The Bargate speci-
mens resemble P. angusta in the paucity of the chambers and the
well-marked segmentation ; but, since their whole test is com-
pressed, they more properly belong to Williamson's species. This
is, moreover, the first recorded occurrence of the species as a fossil.
Two specimens from the Pebble-beds, Littleton.
104. Polymobphhta rhabdogonioides, sp. nov. (PI. XXXiT.
fig. 12 a, 6.)
Test subpyramidal and quadrifacial ; bluntly pointed at the base
and rapidly increasing in width towards the oral extremity. The
test is smooth, and consists of a Polymorphine series of chambers
(slightly twisted as regards the commencement), the margins of
which are deeply sunken, and the chambers themselves, numbering
about five to seven on each face of the test, well inflated, especially
in the case of the more or less central one visible on each face.
The terminal chamber is large and embracing, subquadrangular in
section, but not regular. The aperturo is circular, and with the
margin pectinate. Length inch (0*36 mm.); width diagonally
yUinch (0-23 mm.).
The foregoing species is probably a dimorphous form, combining
Polymorphina with Rhabdogoinun^ and, in the event of other
varieties becoming known, it may be found necessary to form a
distinct genus for this type.
Two specimens from the Pebble-beds, Littleton.
105. Polymorphina frondiculabioides, sp. nov. (PI. XXX1T.
fig. 13 «, b.)
Test subpyriform, but somewhat compressed, tapering more
acutely towards the aboral extremity ; test rhomboidal in section.
Surface smooth, and swollen along the centre of each face. About
1 Neuea Jabrb. 1857, p. 290, pi. xiii. figs. 13-15.
Digitized by Google
1
Vol. 50.] MB. P. CHAPMAN ON THE BABOATE
717
six chambers are visible on each surface, slightly inflated, and
bordered by well-marked sutures. The last chamber is pinched up
towards the apex ; but it embraces the whole width of the test,
alter the manner of Frondicularia and Lingulina. Aperture slightly
elongate, with a stellate border. Length ^ inch (0*37 mm.) ; width
inch (0-19 mm.).
This form also appears to represent a new genus or subgenus,
combining two hitherto distinct generic types.
One specimen from the Pebble-beds, Littleton.
100. Polymorph in a rbgixa, Brady, Parker, & Jones.
P. regina, B., P., & J., Trans. Linn. Soc. Lond. vol. xxvii. (1870)
p. 241, pi. xli. figs. 32 a, b.
A somewhat imperfect specimen and having a compressed tost,
but otherwise referable to this species, was found in the Bargate
Beds, Holloway Hill.
107. Polymorph in a coxcava, Williamson, var. dextimargixata, nov.
(PI. XXXIV. fig. 14 «, />.)
Test adherent, flat on the attached and convex on the opposite
face. Subovate in outline, and sharply pointed at both ends. On
the upper and lower surfaces, in the central area of the test, is
exhibited a regular Polymorphine series, consisting of live chambers
ou the upper surface, and surrounding this is a secondary or later
growth of shell-material, depauperate and thin, which appears to
turn back upon the under surface, forming the adherent portion.
Tho thin, outer, flange-like portion of tho test shows the septation of
five flattened segments. The delicate margin of tho test is broken
up into a fine pectinate edge ; and, by careful observation, the sur-
face is seen to be studded sparsely with minuto prickles. Length
5l- inch (0*05 mm.) ; width inch (0*3 mm.).
Tho typo form P. cowava1 has the attached or lower surface
concave, and the margin of tho test ontire or simply waved ; the
lower surface would of course bo conformable in shape to the object
upon which it grew, so that concavity of surface is no truo distinctive
character in this species.
One specimen from the Pebble-beds, Littleton.
Subfamily It a m u l i n i » je.
Ramultxa, Jones.
108. It amtj lin a (iLOHCHPERA, Brady.
It. (/lobulifera, Brady, Quart. Juiirn. ilicr. Sci. n. s. vol. xix.
(1809) p. 58, pi. viii. figs. 32, 33; id. •Challenger' Rep. vol. ix.
(1884) p. 587, pi. lxxvi. figs. 22-28.
It appears desirable to associate the smooth or prickly, tubular-
and sometimes globular-chambered Iiamuliivt of Cretaceous strata
' Vohpnorphina laden. Tar. concaca, Williamson. ' Hoc. For. Gr. Brit.' 1858,
p. 72, pi. vi. fifTA. 151. 152.
i
718 MB. P. CHAPMAN ON THE BAB6ATE BED8 OF SURREY. [Nov. 1894,
with the recent forms found in moderately deep water, and figured
by Dr. Brady (he. cit.\ and to regard the Dentalina acxdtata of
d'Orbigny 1 as a true Nodosarian form.
A fragmentary specimen of the cylindrical portion of R. globulifera
was found in the Pebble-beds, Littleton ; and a similar one in the
Pebble-beds in Halfpenny Lane, Chilworth.
Family GLOBIGERINHLE.
Globigebtka, d'Orbigny.
109. Globioebjna buxloides, d'Orbigny.
O. buXloidety d'Orbigny, Ann. Sci. Nat. vol. vii. (1826) p. 277, no. 1,
Modeles nos. 17 and 76 ; Brady, ' Challenger ' Rep. vol. be. (1884)
p. 593, pis. lxxvii., lxxix. figs. 3-7.
This species is met with in various Cretaceous and Tertiary beds,
as well as in recent deposits.
The four specimens from the Bargate series are small, but are
distinguishable from the more typical O. crctacca by the turbinoid
form of the spire. Three come from the Pebble-beds, Littleton,
and one from the Pebble-beds, Halfpenny Lane, Chilworth.
110. GLOBioEBrwA cretacba, d'Orbigny.
O. cretarea, d'Orbigny, Mem. Soc. geol. France, vol. iv. (1840)
p. 34, pi. iii. figs. 12-14.
This well-known and common Cretaceous species is represented in
the Bargate series by three specimens, from the Pebble-beds,
Littleton.
Family ROTALIIDJ2.
Subfamily Rotalik^s.
Patellina, Williamson.
111. Patellina corrugata, Williamson.
P. corrugata, Williamson, 4 Rec. For. Gr. Brit.' 1858, p. 46,
pi. iii. figs. 86-89.
This interesting little species has hitherto been found in the
post-Tertiary beds of Scotland and Ireland, and, as a recent form,
usually affects shallow water.
It is somewhat remarkable to find this small and delicate species
in strata as old as the Neocomian, since the various species known
from fossiliferous beds of Cretaceous and early Tertiary ages are of
a stronger and larger build.
Five specimens from the Pebble-beds, Littleton ; and two from
the Bargate Beds, Holloway Hill.
112. Patellina antiqua, sp. nov. (PI. XXXIII. fig. 12 a, 6, c.)
Test nearly circular, superior face convex, and with about five
1 M6m. Soc. gcol. France, tol. it. pt i. (1840) p. 13, pi. i. figs. 2, 3.
Digitized by Google
Vol. 50.] MB. P. CHAPMAN ON THE B A EG ATE BEDS OP SUBSET. 719
whorls of semi-globular chambers arranged spirally ; inferior face
flat, the surface covered with papillae arranged somewhat concen-
trically. Peripheral edge obtuse. Diameter of test inch (0*31
mm.) ; height ff inch (0*1 mm.).
One specimen from the Bargate Beds, Holloway Hill.
Discobbina, Parker & Jones.
113. Discobbina tttbbo (d'Orbigny).
Rotalia (Trochulina) turbo, d'Orbigny, Ann. Sci. Nat. vol. vii.
(1826) p. 274, no. 29 : Modele no. 73.
Discorbina turbo, Brady, * Challenger ' Rep. vol. ix. (1884) p. 642,
pi. lxxxvii. fig. 8 a, 6, c.
This species has previously been found in the Chalk of Maestricht
and some strata of later age ; and as a recent form it is found iu
shallow water, and deeper to 420 fathoms.
One specimen from the Pebble-beds, Littleton.
114. Discobbina orbicularis (Terquem).
Rosalind orbicularis Terquem, * Anim. sur la Plage de Dunkerque,'
1876, p. 75, pi. ix. fig. 4 a, 6.
Discorbina orbicularis, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 647, pi. lxxxviii. figs. 4-8.
Four specimens of this shallow-water form, which also occurs in
Miocene and Pliocene strata, were found in the Pebble-beds,
Littleton.
115. Discobbina plleolus (d'Orbigny).
Valvulina jnleolus, d'Orbigny, « Foram. Amer. Mend.' 1839,
p. 47, pi. i. figs. 15-17.
Discorbina pUeolus, Brady, 'Challonger' Rep. vol. ix. (1884)
p. 649, pi. lxxxix. figs. 2-4.
D. pxleolus has been found fossil in various Tertiary deposits. As
a living form it affects shallow water down to 20 fathoms.
Two specimens from the Pebble-beds, Littleton.
116. Discobbina pabisiensib (d'Orbigny).
Rosalina parisiensis, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826)
p. 271, no. 1 : Modele no. 38.
Discorbina parisiensis, Brady, « Challenger ' Rep. vol. ix. (1884)
p. 648, pi. xc. figs. 5, 6, 9-12.
This species is found in shallow water to a depth of 50 fathoms,
and is recorded fossil from Tertiary strata.
Three specimens from the Pebble-beds, Littleton ; and two from
the Pebble-beds, Halfpenny Lane.
117. Discobbina rosacea (d'Orbigny).
Rotalia rosacea, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826) p. 273,
15 : Modele no. 39.
720 MR. F. CHAPMAN ON THE BABGATB BEDS OF SURREY. [Nov. 1 894,
Discorbina rosacea, Brady, * Challenger* Rep. vol. ix. (1884)
p. 644, pi. lxxxvii. figs. 1, 4.
This is also a shallow-water species, and it is found fossil in
various Tertiary beds.
One specimen from the Pebble-heds, Littleton.
118. Discorbina Bertheloti (d'Orbigny).
Rosalina Bertheloti, d'Orbigny, * Foram. Ilea Canaries/ 1839,
p. 135, pi. i. figs. 28-30.
Discorbina Bertheloti, Brady, « Challenger * Rep. vol. ix. (1884)
p. 650, pi. lxxxix. figs. 10-12.
This species is, in the recent condition, usually found at depths
of less than 500 fathoms.
The forty-two Bargate specimens vary from inch (0*14 mm.)
to -fa inch (0*42 mm.) in diameter. They were found in the
Pebble- beds, Littleton.
119. Discorbina Bertiieloti, var. Baconica (Hantken).
D. Baconica, Hautken, Mitthcil. Jahrb. ung. geol. Anstalt, vol. iv.
(1875) p. 76, pi. x. fig. 3 a, 6.
D. Bertheloti, var. Baconica, Brady, * Challenger ' Rep. vol. ix.
(1884) p. 651, pi. xc. fig. 1 a, b, c.
This variety was described from the Clavulina Szaboi-bcda (Ter-
tiary) of Hungary, and as a recent form is known from depths of
600 to 1180 fathoms.
One specimen from the Pebble-beds, Littleton.
120. Discorbina concinna, Brady.
D. concinna, Brady, 'Challenger* Rep. vol. ix. (1884) p. 646,
pi. xc. figs. 7, 8.
This species was recorded by Dr. Brady from depths of 15-620
fathoms.
Two specimens from the Pebble-beds, Littleton.
121. Dmcobbina buoosa (d'Orbigny).
Rosalina rugosa, d'Orbigny, * Foram. Amer. Merid.' 1839, p. 42,
pi. ii. tigs. 12-14.
Discorbina rugosa, Brady, * Challenger* Rep. vol. ix. (1884) p. 652,
pi. lxxxvii. fig. 3 a, b, c ; pi. xci. fig. 4 a, 6, c.
Seven specimens of this moderately shallow-water species were
found in the Pebble-beds, Littleton.
122. Discorbina obtusa (d'Orbigny).
Rosalina ohtusa, d'Orbigny, 4 Foram. Foss. Vienne,' 1846, p. 179,
pL xi. figs. 4-6.
Discorbina obtuta, Brady, ' Challenger ' Rep. vol. ix. (1884)
p. 644, pi. xci. fig. 9 a, b, c?
This species is represented in the Bargate series by one typical
specimen from the Pebble-beds, Halfpenny Lane, Chil worth.
Digitized by Google
Vol. 50.] Mil. P. CHAPMAN ON THE BABOATE BEDS OF BT7RRET. 721
123. Discobbina YiiABDBBoANA (d'Orbigny).
Rosalind Vilardcboana, d'Orbigny, ' Foram. Amer. Mdrid.' 1839,
p. 44, pi. vi. figs. 13-15.
Discorbina Vilardeboana, Brady, 4 Challenger' Rep. vol. ix. (1884)
p. 645, pi. lxxxvi. figs. 9, 12; pi. lxxxviii. fig. 2.
One specimen of this shallow-water species was found in the
Pebble-beds, Littleton.
124. Discobbina abaucana (d'Orbigny).
Kosalina araucana, d'Orbigny, « Foram. Amer. Merid.' 1839,
p. 44, pi. vi. figs. 16-18.
Discorbina araucana, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 645, pi. lxxxvi. figs. 10, 11.
Thirteen specimens of the above species, which is a shallow-water
form, were found in the Pebble-beds, Littleton ; and one in the
Pebble-beds, Halfpenny Lane, Chilworth.1
Tbuncatulina, d'Orbigny.
125. Tbuncatulina lobatula (Walker & Jacob).
Nautilus lobatulus, Walker & Jacob, Adams's Essays, Kan-
macher's ed. (1798) p. 642, pi. xiv. fig. 36.
Truncatulina lobatula, Brady, * Challenger ' Rep. vol ix. (1884)
p. 660, pi. xcii. fig. 10 ; pi. xciii. figs. 1, 4, 5 ; pi. cxv. figs. 4, 5.
Two specimens of this widely distributed species were found in
the Pebble-beds, Littleton.
126. Tbunoatclina vabiabilis, d'Orbigny.
Truncatulina variabilis, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826)
p. 279, no. 8; Brady, * Challenger' Rep. vol. ix. (1884) p. 661,
pi. xciii. figs. 6, 7.
This form has been noted from the Chalk of Taplow, and from
various Tertiary formations.
Four specimens from the Pebble-beds, Littleton.
127. Tbuncatulina falcata, Reuss. (PI. XXXIV. fig. 15 a, 6, c.)
Truncatulina falcata, Reuss, Sitzungsb. Akad. Wissensch. Wien,
vol. lix. (1869) pt. i. p. 461, pi. ii. fig. 1.
This species was described by Reuss from tho Oligoccne Beds
of Gaas in the South of France, in which deposit it appears to be
very rare.
T. falcata is by far the most abundant species of foraminifera in
the Bargate Beds of Surrey, and the specimens, moreover, agree very
nearly with the original description of the test. There arc, how-
ever, these unimportant differences between the Oligocene and the
1 The specimens of I), araucana, and nlao some of D. rugosa, exhibit a
tendency to become elongate in the plane of their discoid&l growth, somewhat
after the manner of Truncatttlina variabilw.
722 MB. P. CHAPMAN ON THE BAEGATB BEDS OP BUBBBT. [Nov. 1 894*
Neocomian specimens, that in the latter the superior face is perfectly
flat, whilst that of the Oligocene specimen was slightly inflated or
convex. The species is easily recognized by the strongly developed
central boss on the inferior face.
One hundred and fifty specimens of this species were found in the
Pebble-beds, Littleton ; twenty-three in the Pebble- beds, Halfpenny
Lane ; and one in tho Bargate Beds, Holloway Hill.
128. Tbuncatttlina Haidixgerii (d'Orbigny).
JRotaUna Uaidingerii, d'Orbigny, 4 Foram. Foss. Vienne,1 1846,
p. 154, pi. vii. figs. 7-9.
Truncatulina Uaidingerii, Brady, ' Challenger Rep. voL ix.
(1884) p. 063, pi. xcv. tig. 7 a-c.
One specimen of this species, which occurs in tolerably deep
water at the present day, and also as a Tertiary fossil, was found in
the Pebble-beds in Halfpenny Lane.
129. Truncatulina Wubllebstobpi (Schwager).
Anomalina Wuelhrstorfi, Schwager, ' Novara ' Exped., geol. TheiL,
vol. ii. (1866) p. 258, pi. vii. figs. 105, 107-
Truncatulina Wuelhrstor/i, Brady, 'Challenger* Rep. vol. ix.
(1884) p. 662, pi. xciii. figs. 8, 9.
This species is characteristic of deep water as a recent form. It
was originally described by Dr. Schwager from the Pliocene beds of
Kar-Nicobar. t • i j
Twenty-three specimens from the Pebble-beds, Littleton ; and
one from tho Pebble-beds, Halfpenny Lane.
Anomaltna, d'Orbigny.
130. Anomalina ARIMINEN8IS (d'Orbigny).
Planulina ariminensis, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826)
n 280 nl v. figs. 1-3 bis : Modele no. 49.
P* ILtiina Brady, • Challenger' Rep. vol. ix. (1884)
p. 674, pi. xciii. figs. 10, 11.
This species has hitherto been found in the Chalk and Tertiary
strata As a recent form it is chiefly confined to shallow or
moderately deep water. Two specimens were found in the Pebble-
oeds, Littleton.
131. Anomalina ammonoideb (Reuss).
Bosalina ammonoides, Reuss, < Verstein. bohm. Kreid.' pt. i. (1845)
p. 36, pi. viii. fig. 53, pi. xiii. fig. 66
Anomalina ammonoides, Brady, < Challenger Rep. vol. ix. (1884)
p. 672, pi. xciv. figs. 2, 3.
This species is a well-known Cretaceous and Tertiary fossil, and
is also found in recent deposits, from depths of 37 to 1 350 fathoms.
Two specimens were found in the Pebble-beds, Littleton.
Digitized by Google
VoL 50.] MB. F. CHAPMAN OK THE BARGATE BEDS OF SUBSET. 723
132. Anomaliwa gbossebugosa (Giimbel).
Truncatulim grotterugota, Giimbel, Abhandl. bayer. Akad.
Wissensch. 2te CI. vol. x. (1868) p. 660, pi. ii. fig. 104 a, b.
Anomalina groaserugota, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 673, pL xciv. figs. 4, 5.
This is a fairly deep-water species, and it also occurs fossil in
beds of Tertiary age.
One specimen from the Pebble-beds, Littleton.
PuLvnroxiKA, Parker & Jones.
133. PuLvnruxraA ptoctulata (d'Orbigny).
Botalina punctulata, d'Orbigny, Ann. Sci. Nat. vol. vii. (1826)
p. 273, no. 25 : Modele no. 12.
Pulvinulina punctuhita, Brady, ' Challenger ' Rep. vol. ix. (1884)
p. 685, pi. civ. fig. 17 a-c.
A small and not very typical example of this species was found in
the Pebble-beds, Littleton.
134. Pulvhtclih a Sen bei bebsii (d'Orbigny).
Botalina SehreibertU, d'Orbigny, 'Foram. Fobs. Vienne,' 1846,
p. 154, pi. viii. figs. 4-6.
Pulvinulina Schreibertii, Brady, ' Challenger ' Rep. vol. ix. (1884)
p. 697, pi. cxv. fig. 1 a-c.
This species appears to be restricted to shallow water. As a
fossil it had hitherto made its first appearance in Miocene strata.
One specimen from the Pebble-beds, Littleton.
135. Pulvihulina Kabsteni (Reuss).
Botalia Kartteni, Reuss, Zeitschr. deutsch. geol. Gesellflch. vol. vii.
(1855) p. 273, pi. ix. fig. 6.
Pulvinulina Kartteni, Brady, 4 Challenger' Sep. vol. ix. (1884)
p. 698, pi. cv. figs. 8, 9.
P. Kartteni has been recorded from beds of Upper Cretaceous
age, and also from later Tertiary formations. As a recent form it
appears to be restricted to shallow water, and it is usually found in
high latitudes.
Four specimens from the Pebble-beds, Littleton.
136. Pulvihuliha blboaks (d'Orbigny).
Botalina (Turbinulina) elegant, d'Orbigny, Ann. Sci. Nat.fol. vii.
(1826) p. 276, no. 54.
Pulvinulina elegant, Brady, 'Challenger' Rep. vol. ix. (1884)
p. 699, pi. cv. figs. 4-6.
P. elegant seems to make its earliest appearance in beds of
Liassic age, and it is found in most important formations of later
date. The species is closely allied to P. Parttchiana (d'Orbigny),
but the former represents the shallow-water type, and it is this
form which is present in the Bargate series of foraminifera.
One specimen from the Pebble-beds, Littleton.
Q. J. G. 8. No. 200. 3 d
724 MR. V. CHAPMAB OH TUB BA BOATS BEDS OF SURREY. [NoV. 1894,
Rotaija , Lamarck.
137. Rotalia Bbocarii (Linne).
Nautilus Beccarii, Linne, * Syst. Nat' 12th ed. (1767) p. 1162 ;
ibid. 13th (Gmelin's) ed. (1788) p. 3370, no. 4.
Rotalia Beccarii, Brady, * Challenger' Rep. vol. is. (1884) p. 704,
pi. cvii. figs. 2, 3.
This species has been noted from Upper Cretaceous strata, as well
as from beds of later age, and is well known as a shallow-water
form.
One specimen from the Pebble-beds, Littleton.
Family NtJMMULINID^E.
Subfamily Polystombllibj.
Noxiohtfa, d'Orbigny.
138. NoNioBTBA kapha (Fiohtel & Moll).
Nautilus scapha, F. ft K. ( Teat. Micr.' 1803, p. 105, pi. xbc.
tigs. d—f.
Nonionina scapha, Brady, * Challenger ' Rep. vol. ix. (1884)
p. 730, pL cix. figs. 14, 15, and 16?
This species has been noted from beds of Miocene age, and others
of later date.
One specimen was found in the Bargate Pebble-beds at Littleton,
which is not very typical, but somewhat closely resembles fig. 16 in
tho * Challenger ' Rep. (loe. tit.).
Poltbtomblla , Lamarck.
139. Polystoitella ACULEATA, d'Orbigny.
P. aculcata, d'Orbigny, 4 Foram. Foss. Vienne,' ] 846, p. 131, pL vi.
figs. 27, 28.
This species was originally described from the Miocene ; and it
occurs in the Bargate Pebble-beds at Littleton (two specimens).
In the foregoing notes upon the foraminifera of the Bargate Beds
of Surrey, 139 species and varieties are recorded.
Of these, 11 are described for the first time. There are, besides,
1 07 which have hitherto been unrecorded (so far as I am aware)
from beds of Ncocomian age.
The following 10 species and varieties have been known previously
from recent deposits only, namely, Ilaplophragmiumfolxaceumy Brady";
Virgulina suldepressa, Brady; Ehrenberyina pupa (d'Orbigny);
Polymorphina tororia, Reuss, var. cuspidata, Brady; P. oblonga
Williamson; P. regina, Brady, Parker, ft Jones; Discorbina
Berthelotx (d'Orbigny); D. eoneinna, Brady; D. Vilardeboana
<d*Orbigny) ; and D. araucana (d'Orbigny).
Vol. 50.] MR* P. CHAPMAN ON THE BAROATE BEDS OF SURREY. 725
The large number of forms new to the Neocomian fauna, as
known elsewhere, is undoubtedly duo to the circumstance that the
deposiU of the Bargate series belong almost exclusively to the
Laminarian and Coralline zones.
Taking into consideration the facts that 23 per cent, of the forms
here recorded are almost peculiarly Neocomian types, that these
added to knowu Cretaceous and Tertiary species amount to 122 or
87 per cent, (the latter additions probably being duo to the fact that
the Neocomian strata have not been so extensively examined in regard
to their llhizopodal fauna as might have been desired), it is extremely
probable that the microzoic fauna of the Bargate series is almost
entirely, though (since we have the presenco of a few Jurassio species)
not quite indigenous to the deposit.
In conclusion, I tender my sinoerest thanks to Prof. T. Rupert
Jones, F.R.S., and Prof. J. W. Judd, F.R.S., for much invaluable
aid and advice ; to Dr. G. J. Hinde, for his kindness in furnishing
the notes upon the sponge-spicules ; to Dr. W. Frasor Hume,
F.G.S., for the valuable notes on the denser minerals of the
sands f the Bargate series ; to Graf zu Solms-Laubach of Stras-
burg, a d G. Murray, Esq., of the Botanical Department of tho
British Museum of Natural History, for oxamining the alga-like
bodies of the Bargate limestone ; and to Dr. J. W. Gregory for his
kind assistance regarding some of the doubtful polyzoan remains.
Distribution op the Ostbacoda in toe Bargate Beds
op Surrey.
Littleton.
Chil worth.
1.
*
2.
*
i 3.
n
„ var. reticulata, J. if H.
4.
F>
*
r..
*
<•».
>'
*
*
7.
"
: 8.
>»
#
9.
M
*
10.
"
*
11.
l»
»
12.
>■
*
13.
n
btpapillata, ftp. nov
•
14.
•
#
15.
i)
„ var. virginea, Jones ...
#
10.
• »
•
17.
#
18.
»
•
19.
»»
«
»
»•
3d2
i
726 MB. P. CHAPMAN ON THE BABOATB BEDS OF SFRREr. [NOV. 1 894,
DlBTBIBUTION OP THE FOBAMTNTPERA IN THE BaBOATE BEDS
OP SUBSET.
1.
2.
3.
4.
5.
*».
7.
8.
9.
10.
11.
12.
13.
14.
15.
10.
17.
18.
10.
20.
21.
22.
23.
24.
25.
21 i.
27.
28.
20.
30.
31.
32.
33.
31.
35.
37.
38.
31).
40.
41.
42.
43.
44.
45.
4<».
47.
Miliolina agglutinins {if Orb.)
Pianispirina obseura, sp. nov
Haplophragitiiuin agglutinate (d'Orb.) .. .
„ llmnbuldti ( fi'russ)
,, irregulare (Horn.)
,, foliao'inn, Brady
einariatum, Brady
„ aouthlorsatum, itantkcn.
*
*
iit'uoonJKLntuii, fip. not' ! *
nouiimiuoidcs,
depresstmi, Jones ..
Aiomodi^ous incertus (d'Orb.)
„ gordiali* \J. 4" P.)
,, ehan>i(ii-s {■). 4' P.)
,, pleurotomarioides, *p. nov
Trochammin.-i squaumta. -/. $ P., var. limbata,
var, iwv.
Textularia sapthdii. Ihfr
granun, d Orb
pni'lunga. !!> ns.<
minuta, B< rthftin
agglutinins, d'Orb
t ro<-li it», d'Orb
turri*, d'Orb
Verneuilina triquetra {^\finist.)
Tritaxia tricarinaia. h'>
Spiroplccta uniurUns 1 t\ J.) ...
biformis ( I'. A J.)
Caudryma pupoidis, d'Orb
,, bamdn. S.;hwag< r
liliformiB, Btrthfliit-
Valvuliua fMiiii-a, 1'. \ d
„ fuwa { J >>//.)
Bulimina polystjoplia, h'russ
pop* »idos, '/"Orb
allinis, tl' f h-b
ovata, d'Orb
pyrulfi. d Orb
obliqua, d" Orb
Prosli, lb
obtusa, d'Orb
M urchin* m iann, d' Orb
brvviu, <f Orb
Virgulina subsquamo-a. t)/</- r
!( «<id>dt'pvr-sa, llrndij
Bolivina trxlilarioidt/*, lUasn
(?) ,, dilat.ata. };> ?'.v<
Cassidulina «ubglobosa, Brady
*
*
;
la
o
*
*
-
*
*
»
•«
■
f
*
«
<
*
*
*■
*
to
a
a
-a
o
1 S>
I ~
1 c
. Pi
>
*
*
*
-
*
*
>
»
*
Digitized by Google
Vol. SO.] MB. F. CHAPMAN ON THE B ARC ATE BEDS OF SURREY.
Distribution of the Fobamxnifbba (continued).
727
4S.
49.
50.
51.
52.
53.
54.
55.
50.
57.
58.
59.
(JO.
(51.
r»2.
03.
04.
65.
CC.
07.
OS.
09.
70.
71.
72.
73.
74.
75.
70.
i < .
78.
79.
80.
81.
«*J.
83.
84.
85.
H».
87.
h8.
89.
90.
91.
9_\
93.
94.
95.
90.
97.
...
Ehrenbergina pupa (cTOrb.)
Lageua globosa (Mont.) ,
,, apioulata. Rcuss ,
„ la'vifl (Mont.)
„ atnitioosta, Iteus*
,, Meveriana, .7*. fn>v
Nodosaria (l)ontalinn) brevis, (TOrb
,, (,.) Roemori, 2\ntf/.
,, („) xipliioidc.-, R' uss
limbata, (V(hh ,
Kontannesi. Berth. ...
(1).) obscura. Kchm ..
tonuieostii. lint?*
prisniatica, lirutv
Liugulina carinata, d Orh
„ Bomioniata, lit ass
„ „ vur. craa&a, var. nov
Frondicularia brizrcformis. Bom
Marginuliua linearis, h'ruf-s
debilis, Bert Jul in
„ compressa, d'Orb
a-quivocn, Iteuss
Jonesi, Hams
,, striatocostata, fimss
,, Munieri, Ikrthelin
Vaginulina legumen (Linne)
arguta, Iicum
sparsienstata, Heuw
,, uoorotniann, sp. vol'
Criatellaria tricarinolla, Iieuss
vt^Lita, BrrtMin
italiea (/>/>.)
sulcifcra, Iieuss
coniplanata, Kerns
parallela, Iieuss
Sclilopnbachi, AV//.s.s
orepidula (/•'. .y M-)
grata, I\di» ,
(!vnibi»id('s, dOrd
laevigata, Hcum
acutauricularie (F. .j" M) .. ..
lironni (Rom.)
oligoftfgia, JiCitsjf
rotubita (I,am.)
cultrata (Monff.)
gibba. d Orb
convergonn, Horn
prominula. Units
incgalopolitaiia (lieu**)
varians, Born
••
.1
M
•■
>»
>1
*4
ton.
V,
0
_£
! Litt
Chi:
#
*
#
#
•
#
*
*
*
#
•
#
*
*
*
#
1 #
1 *
1 »
»
*
#
*
*
»
#
*
«
*
«
*
*
*
»
*
*
*
*
#
#
»
#
«
*
1 *
»
•1 *
! *
1
*
bo
c
bp
'Sk
u
o
P
Digitized by Google
728
KB. F. CHAPMAN OX THE BARQATE BED8 OF SURREY. [Nov. 1894,
Distribution of tile Fouamin ifkra (continued).
98.
99.
100.
101.
102.
103.
104.
105.
L0&
107.
108.
109.
110.
111.
112.
1113.
114.
115.
116.
117.
lis.
111*.
120.
121.
122.
123.
124.
12."..
126.
127.
128.
129.
130.
131.
132.
133.
134.
135.
13fi.
137.
138.
139.
»>
w
>1
l>
>I
*t
tl
!
Polymorphina umygdaloides, Jiru*s
„ sororia, Ileitis, var. cuspidate, Brady
„ gutta, d Orb
communis, a* Orb
compreeaa, d Orb
oblonga, Will
rhabdogonioides, tp. nov
frondicularioides, »p. nov
rcgina, B„ P., £ J.
coucnva, Will., rar. deutimarginata,
tar. nov.
Ramulina globulifera, Brady
Globigerina bulloides, dOrb
„ cretaeea, dOrb
Patellina corrugata, Will
11 antiqua, »p. nov
Diacorbina turbo (dOrb.)
„ orbicularis Cl'erq.)
,. pileolus (d Orb.) ....] •
parisiensis {dOrb.) •
rosacea (dOrb.) I •
Bertheloti (d Orb.) J «
„ var. Baconica (Hani ken) ... •
condnna, Brady »
rugosa (dOrb.)
obt usa (dOrb.)
Vilardeboana (dOrb.) *
„ araucana (dOrb.) #
Truncatulina lobatula ( W. §f J.) *
11
* 1
99
11
11
variabilis, dOrb
falcata, Reuse
Haidingerii (dOrb.)
Anomalina Wuellerstorfi (Schio.)
„ arituinensis (d'Orb.) »
„ ammouoides (Iieu&s) •
„ grosserugosa (Giimbtl) #
Pulvinulina punctulata (d Orb.) 1 «
„ Schreibcrsii (dOrb.) »
,, Karstini (lieu**) | •
„ elegans (dOrb.) *
Botalia Beccaru (L.) 1 •
Nonionina scapba {F. $ M.) •
Polystomella aculeata, dOrb •
o
%
-=
s
o
*
«
Quart Journ Geo! Sec Vol L. PI. XXXIV
F.CKapmiiri del F H Mich*el hth Mint pits Brow imp
BARCiATE FORAMINIFERA
Digitized by Google
Vol. 50. j MR. P. CHAPMAN ON 1MB BARGATE BEDS OP SURREY. 729
EXPLANATION OF PLATES XXXIII. & XXXIV.
Plate XXXIIL
Fig. 1. Cythere venculota, sp. nov. ; a, right valve ; b, edge view ; c, end view.
X 40.
2. Cytheridea bicarinata, Jones 4 She r bom, var. noduloaa, var. nor. ; a,
left valve ; b, edge view ; c, end riew. X 76.
3. Cytheridea vellieata, ep. nor. ; a, left valve ; 0, edge view ; c, end view.
X 60.
4. Cytheridea fenestrafa, sp. nov. ; left valve. X 60.
5. Cytheridea bipapillata, sp. nov. ; a, left valve ; b, edge view ; c, end
view, x 60.
6. Cytheropteron rtticulosum, ep. nov. j a, left valve ; b, edge view; c, end
view, x 60.
7. Cytheropteron cottul\ferunx, Bp. nov. ; a, right valve ; b, edge view of
carapace ; c, end view, x 60.
8. One of the small objects obtained from the riliceous residue of the
Bargate limestone from Littleton, near Guildford, and somewhat
resembling in external form the calcareous alga Lithothamnion.
X 60.
9. A specimen obtained from the siliceous residue of the Bargate lime-
stone from Littleton, and which is probably a species of Corallina.
X 21.
10. A small object common in the siliceous residue of the Bargate lime-
stone from Littleton, composed of green chalcedony, and which may
possibly have some affinities with Diplopora (a calcareous alga). X 60.
11. (?) A replacement of a bryozoan, in green chalcedony, occurring
commonly in the siliceous residue of the Bargate limestone from
Littleton, x 60.
12 a, b, c. Patcllina antiqua, sp. nov. x 60.
Plate XXXIV.
Fig. 1 a, b, e. Planispirina obscura, sp. nov. X 45.
2 a, b. Haplophraymium neocomianum, sp. nov. X 50.
3 a, b, c. Ammodixus pleurotomarioides, sp. nor. X 35.
4 a, b, c. Trochammina gqtiamata, Jones & Parker, var. limbata, var. nov.
X 60.
5. Bulimina polystropha, Reuss. x 60.
6 a. b. Khrenberaina pupa, d'Orbigny, sp. x 60.
7 a, b. Lagena Meyeriana. sp. nov. X 60.
8 a, b. Linguiina semiornata, Reuss, var. cratta, var. nov. X 60.
9 a, b, Frondicularia bri*<rformis, Bornemann. X 60.
10 a, b, 11. Vagxnulina neocomiana, sp. nov. X 60.
12 a, b. Polymorphina rhabdogonundes, sp. nov. x 60.
13 a, b. Polymorphina frond icularioide*, sp. nov. X 70.
14 a, b. Polymorphina concava, Williamson, var. dentimarginata, var. nov.
X 60.
15 o, b, c. Truncatulina fakata, Reuss. x 60.
Discussion.
Mr. T. Leighton could not admit that thoro was any uncon-
formity between the Folkestone and Bargate Beds in this district ;
he thought that what was referred to as such would turn out to be
false bedding. He had recently described an interesting section of
this junction in Abinger Lane (Proc. Geol. Assoc. vol. xiii. p. 166)
with considerable detail, because the condition of things there shown
730 MB. F. CHAPMAN ON TITF. BABGATE BEDB OF 8T7BBBY. [Nov. 1 894,
was just such as in a smaller or less clearly exposed section
would be ascribed to an unconformity, but it was clearly false-
bedding. He thought that the Society was much indebted to the
Author of the paper for his microscopical work, which he hoped
would be continued, because it would be an advantage if certain
l>eds of the Lower Greensand could be correlated thereby ; for
instance, if the beds of the Horsham Road-cutting could be corre-
lated by means of the foraminifera, a great result would be obtained
by the examination of these small organisms.
Prof. Judd called attention to the great importance of the
Author's researches, not only in increasing our knowledge of the
Cretaceous microzoa, but in giving evidence of the existence in the
immediate neighbourhood of the district described by him of
Jurassic rocks, for he has found a Lower Greensand rock filled with
derived grains of oolite, like those occurring in the Richmond boring.
Mr. Whttaxeb, Dr. G. J. Hnn>E, Mr. Toplby, and Prof. T.
Ritpebt Jones also spoke.
[Note. — In the abstract of this paper — which was submitted to
the Secretary by the Author— an unconformity was inadvertently
mentioned as occurring between the Folkestone and the Bargate
Beds. As in the paper itself, it should have been referred to as an
eroded surface (contemporaneous erosion). — Sept. 7th, 1894.]
Digitized by Google
Vol. 50.]
CONE-IK-CONE IN THE * DEVONIAN ' SEKIKS.
731
43. Conb-in-cone : J low it occurs mi the ' Devonian ' Series in
Pennsylvania, U.S.A., with further Details of its Structurr,
Varieties, etc. By W. 8. Greeley, Esq., F.G.S. (Read
May 9th, 1894.)
[Abridged.]
[Plates XXXV. & XXXVI.]
The objects of this communication are : — (1) to clearly demonstrate
that cone-in-cone, in its normal condition, very frequently possesses
' inverted cones/ i. e. cones with their apices pointing upwards, aB AA,
as distinguished from what may be called ' ordinary ' cone-in-cone,
wherein the points of the cones face downwards, as W ; (2) to show
that Mr. John Young's explanation of the formation of both the
ordinary and the inverted cones is probably erroneous,1 because
it altogether fails to account for the phenomena observed; and
(3) to describe certain forms and inner structures of the rock, not
hitherto published ; concluding with a few suggestions regarding
the probable origin and mode of formation of the conic masses.
1. Inverted Cones.
Instances of layers of cone-in-cone forming portions of nodules
were referred to in 1820,a but, so far as I know, no trustworthy
illustrations of inverted cones appeared until those given in my own
paper in 1887.3 Now, these 4 finds ' seem to afford sufficient evidence
to prove that Mr. Youngs theory of cone-formation must be rejected,
provided (as it is natural and reasonable to suppose) that true cone-
in -cone can be produced in one way alone. But Mr. Young, having
come to the conclusion that the Scottish cone-in-cone, from which
he obtained his specimens and constructed his theory, was a forma-
tion resulting from the ebullition of gases passing upwards through
a plastic sediment during deposition in local areas, altogether
repudiated the idea of true conic layers having the bases of the
cones facing downwards. He endeavoured to account for the
existence of nodules upon whose upper surfaces cone-in-cone
occurred with the points in the direction of centre of the mass, and
upon whose under surfaces similar structures existed with their
apices facing in the same direction, .by employing the phenomenon. of
contraction. This he conceived had acted so powerfully on these
cone-in-cone-concretions as to cause them to curl up, hedgehog-like,
to such an extent that the conic layer on the top was stretched
and even carried round to, and presumably welded together upon,
the under side. The very aspect and structure of the nodules that
I had studied prevented me from accepting, even for a moment,
1 Trans. Oeol. 80c. Glasgow, vol. viii. (1885) p. 1.
a Trans. Oeol. 80c. ser. 1, toL t. pt. 2, p. 375.
* • Notes on Cono-in-oone Structure,' GeoL Mag. p. 17.
732 JIB. W. 8. GRESLEY 01T COKE-m-COWE Rf THB [Nov. 1894,
that explanation ; and as my illustrations of inverted cone-in-cone
were, in effect, slighted by Mr. Young, the next thing to be done,
in order to positively demonstrate the existence of inverted cones,
was, if possible, to discover such specimens of the formation as
could be photographed in situ. There could then be no possibility
of error of observation, nor any room left for doubt that the conic
masses were not bent or curled round so as to bring the originally
flat cone-in-cone upside down upon the under side of the containing
rock or nodule. Mr. Young wrote 1 : — " Since my paper was
printed in 1886, 1 have obtained many other illustrative specimens
from our Scottish coalfield. These clearly show that the radiation
and inversion of the cones, in nodular masses, was due to after-
secondary causes, the cone structure being first, the formation
of the nodules being second, and the amount of radiation, and
inversion of the cones, affords a measure of evidence as to the
amount of contraction that has taken place amongst these nodules
previous to complete solidification." Why Mr. Young did not supply
a good illustration of a typical sample of one of these curiously-
inverted cone-in-cone-bearing nodules we were not informed;
perhaps he will favour us with one after he has seen this paper, so
that they may be compared with the specimens herein described.
2. Typical Inverted or Double Cone-in-cone, in the Portage
Flags, Pennsylvania.
In 1890 the present writer came to reside at Erie, Pa., and it rather
curiously happened that this very locality, which is situated on Lower
Carboniferous or Devonian (?) strata, was a noted one for cone-in-
cone.3 Moreover, I was furnished with a copy of a paper on the
Erie cone-in-cone, written in 1880, by Dr. T. D. Ingersoll of that
city, whose valuable aid in discovering specimens and working up
the subject I have pleasure in acknowledging here. The cone-
structure is very prevalent in North-western Pennsylvania ; it
occurs on the horizon of a very persistent bed of limestone,
called the Ferriferous Limestone. This is a stratum usually several
feet thick ; but almost always, when and wherever it thins down
to about 4 inches or less, the cone-in-coue formation has been
developed in it and the limestone is quite earthy. But it is several
hundred feet deeper in the series that the formations which constitute
the subject of this paper are met with.
The typical cone-in-cono in the vicinity of Erie occurs at several
more or less definite horizons in the Portage series. These rocks
lie almost horizontally, cropping out boldly in cliffs of moderate
elevation all along the southern shore of Lake Erie for 80 or 90
miles, and as the coast is cut into every few miles by streams enter-
ing the lako through ravines, excellent opportunities are afforded of
1 Qeol. Mag. 1802, p. 279.
8 Pennejlv. 2nd Geol. Surv. Report, Q4 (1881), p. 291.
Vol. 50.]
' DEVONIAN ' SERIES IK FEXN81LVA3IA.
tracing and scrutinizing the various layers of shale, sandstone, etc,
and of gaining access to the innumerable and varied exposure*
of cone-in- cone which they enclose. The Portage strata here are
marvellously uniform in character and composition : thin, flaggy,
current-bedded, pale-grey sandstones are interbeddcd with laminated
shales of various shades of purple, grey, etc, the changes from
one layer to another being very frequent ; but horizontally, each
bed, band, or layer maintains its individuality in a marked degree.
The shales, as well as the surfaces of the more siliceous beds, reveal
abundant evidence of organic life — we find trails, tracks, and burrows
of worms and other creeping things by the myriad ; fucoids, etc. are
not uncommon ; mud-flows, rill and ripple-markings innumerable,
besides very numerous other markings of a puzzling nature.1 While
a few of the sandstone-layers become thick enough here and there
to quarry, the shales, though often containing alum and lime, are
never worked. Natural gas and a little petroleum pervade the
strata to some extent.
The cone-in-cone seems to occur on certain definite horizons and to
lie parallel with or interbedded in the shales, etc. It occurs in sepa-
rate patches, discs, aggregated or clustered layers or flattish cakes,
whose contour is round or irregular-curvilinear. Within a hori-
zontal distance of 100 feet one may come upon half a dozen or more
individual conic masses on the same plane, while in the next 100
or even 1000 feet none may be found. In general dimensions 20
feet across or long is the size of the largest single layer that the
author has seen ; and individual masses more than 0 or 6£ inches
in thickness are very scarce. In the separate layers or lenses the
heights of the cones never exceed about 4 inches and often run as
low as ^ inch : indeed, they taper or die out to nothing. Some
conic masses are composed of as many as six or eight separate heights
or zones of cone-in-cone layers one above another, no two layer*
being of uniform dimensions, and the apices of the cones of the
lower layers are direoted upwards, or rather towards the central
stratum of the mass. Very few of the layers of cone-in-cone occur
singly.
The cone-structure is harder than the surrounding strata, but in
coloration there is practically no difference. Both upper and lower
surfaces of the layers of cone-in-cone often present a wavy form, such
as is seen in most current-bedded fissile sandstones. PI. XXXV.
fig. 1 shows a naturally exposed and weatherworn transverse
section of a characteristic aggregate of individual and separated
layers of the cone-in-cone in *ttu, forming or constituting a typical
Portage conic mass : in this specimen there are three separate layers
of cones above the nucleus or central layer. This nucleal layer lies
just above the dark shadow to the right of the watch. In PI.
XXXV. fig. 2 this specimen is drawn in diagrammatic form, in
order to bring out more clearly the relative position and number of
conic cakes revealed in the mass : it also gives point to the nucleal
stratum — a current-bedded stone, and the leading features of the
1 Pennsylv. Geol. Suit., Summary Final Report, toI. ii. (1892) p. 1349.
Digitized by Google
734
M It. W. 8. GRL8LEY ON COKB-IX-COHE IN TUB [Nov. 1894,
surrounding shales. Upon the layer of stone are two separated
cakes of cones on the same plane— one above the watch, the other
over the dark cavity below the core or nucleus. Above and between
these two cone-patches is a layer of shale. Over this comes a well-
developed layer of cones, then another shale-layer, and above that the
third height of cones, which thins out before it reaches the edges of
the underlying conic layer. Just beneath the core or nucleus, and
level with the bottom of the watch, the inverted conic layer occurs,
as the figure more or less clearly shows.
No two conic masses appear to be alike ; not only do the size,
position, thickness, perfection, and number of the overlying and the
underlying (ordinary and inverted) conic cakes vary extremely, but
the entire structure — the tout ensemble of the formations — is very
curious, differentiation being a docided feature.
Wo find then that this cone-in-cone is characterized by its
sandwiched, or cake- above-cake, shale — or sandstone — interbedded
structure, and possesses an obvious and yet an indefinite nucleus-like
centre, towards which the cones and parts of cones radiate. But the
nucleus of these Portage masses is not usually a nodule 1 ; it is only
Section through a typical cane-in-cone-bearing nodule, Portage Series,
Pennsylvania.
[The oone-in-cone portions are confined to brood circular bands, tapering
away at their edges, upon both the upper and lower surfaces.]
a portion of what appears to be an ordinary layer of false-bedded
sandstone. Now, where the sandstone comes within the range or
confines of the conic masses it is decidedly calcareous. The cone-
in-cone invariably contains calcium carbonate, while the enveloping
layers of shale rarely show more than a trace of that salt.
It is important also to notice that cone-in-cone, although
associated and sometimes intricately intercalated with the thin
arenaceous laminae, is nevertheless confined to the more argillaceous
— the shaly layers. Another feature is that an individual layer or
lenticular cake of tho structure has not restricted itself in process of
formation to any one particular band of the shale, but, as shown in
PI. XXXV. fig. 5, incorporates portions of several different bands.1
That there exists any difference in any particular between the conic
1 When well-developed nodular masses carrying cone-in-cone do occur in
these beds, the upper and lower coatings of the cones, instead of being drawn
around the rims of the nodules (as Mr. Young appears to find them), ore
squeezed and somewhat derated into annular forms near the rims of the stone
on either side (see fig.).
3 Does not this fact alone prove that Mr. Young's idea of the origin, etc. of
the formation cannot stand ?
Vol. 50.] * DEVONIAN ' SERIES IN J'ENNSTLVANIA. 735
structures, normal and inverted, I have failed to perceive ; unless
one knows which is which, by actually seeing it and marking it
in ritu, it is not possible to tell whether a specimen is of inverted
cones or not. This remark applies to entire assemblages of conic
cakes (e. g. PL XXXV. fig. 1), as well as to separate layers of cones
(PI. XXaV. fig. 5). Dr. Ingersoll possesses specimens of cone-
in-cone from the Pacific coast, California. These the author has
examined, and he sees no material difference between thorn and the
Pennsylvanian Portage cones ; in fact, they are remarkably similar.
3. Detailed Description of the Cone Formation.
The largest, best developed, and most perfect individual cones of
any separate conic cake are usually found near the ceutre of the cake.
They are surrounded laterally by numerous, more or less scaly or
flaky segments of cones, generally arranged concentrically with the
larger cones, and wrap round or dovetail into each other, being
more and more obliquely inclined towards the bedding-planes as
they approach the rim of the disc (see PI. XXXV. figs. 2 & 5),
where they dwindle down to nothing. Viewed in the direction of
the axes of the cones, their apices have a minutely oolitic aspect ;
that is, the points of all the cones or parts thereof which occupy or
start from the apex-plane of the conic cakes resemble the spotted
surface of oolite, though in reality every apex is probably as fine as
a pin-point (PI. XXXVI. fig. 20). A characteristic feature of the
cone-structures is that the bases of the cones and 4 conic scales '
(PI. XXXV. fig. 3) in transverse section reveal a serrated surface
(PI. XXXV. fig. 5); the outer edges of separate conic scales pro-
ject a little beyond, as well as over the inner and lower margin of
the adjacent scales. But instead of asking the reader to follow
closely several pages descriptive of each important detail in the
structure of cone-in-cone (most of which details have been described
elsewhere by Sorby, Newberry, Dawson, Young, Colo, Dickinson,
Marsh, Mantell, and the author, and are probably more or less
well-known or easily accessible to Fellows of this Socioty), the
writer would ask them to carefully study the illustrations which
accompany this paper and the explanations annexed to them. With
regard to the * clayey * or * dark rings ' of Mr. Young, and the micro-
scopical structure of the formation (as the material of the walls of
the cones and conic scales may, for convenience, be termed), I
would draw the reader's particular attention to PI. XXXV. figs. 7,
8, 10 and 10 a, and PI. XXXVI. figs. 11, 12, 13 and 13 a, and 14.
Previously to the present writer's first paper on cone-in-cone,1 no
one appears to have studied or published anything relating to the
microscopical structure. Mr. Young's specimens do not seem to have
revoaled anything of it, beyond the clayey rings on the backs of the
cones. Prof. G. A. J. Cole, however,3 observed it and confirms my
1 Geol. Mag. 1887, p. 17.
3 Mineralog. Mag. vol. x. (1893) p. 136.
Digitized by Google
736 MB. W. S. 6RBBLET 03T COXE-IS-COXB IJT THE [Nov. 1 894,
notice of it, but the illustrations which accompany his paper do not
seem to be of specimens sufficiently well-developed to display the struc-
tures referred to, namely, those brought out in PI. XXXVI. figs. 1 1
and 12. I also venture to believe that my illustrations (PI. XXXV.
figs. 7 and 8), which show the curiously wrinkled or corrugated
surfaces of the bases of the cone-in-cone, are new in this connexion.
Assuming, then, that the all-important characteristics and sufficient
detail of the cone-material have been grasped and fairly under-
stood— for so complex a structure is by no means easy to describe,
however easy it may be to illustrate, — we may now proceed to
summarize the observed facts and draw deductions therefrom.
4. Conclusions.
(1) The perfectly normal and practically unchanged and undisturbed
condition of the cone-in-cone-bearing Portage Beds in North-
western Pennsylvania furnish conclusive evidence that this
cone-in-cone is there in place, and moreover that it was formed
since and not pari pasrn with the enclosing strata. It is there-
fore a secondary product, and a product of alteration.
(2) The nests or multiple-heights (one layer above another) of the
conic material, from their very position or lie in the strata,
show that they were formed simultaneously; but how long
the process took, at what depth it operated, and whether it is
going on still or not, we do not know.
(3) That each and every individual layer, as well as nest of cones,
has been formed from practically the same materials and in the
same manner is sufficiently obvious.
(4) The cone-forming conditions (whatever they were) evidently
had an affinity for certain horizons in the Portage series, and
were also such that the ooue-formations were originated more
in one place than another — they seem to be numerous in some
places, scarce or absent in others, on the same stratigraphical
horizon.
(5) The cone-in-cone avoids the harder and more sandy layers, but
does not occupy the whole thickness of the shaly layers inter-
bedded, in very frequent alternations, with the sandy ones.
The coro or nucleal layer of the conic masses certainly con-
tained the * germ,' so to say, of the structures (probably some
fossil) ; and, as it contains a considerable quantity of calcium
carbonate, which outside of the conic layers is absent, and
which also pervades other arenaceous lamine that have been
incorporated in the * unconed ' parts of the structure, it is evident
that lime was an essential agent in the phenomena.
(6) The swelling which occasionally accompanies cone-in-cone is
probably due to the acquisition of lime from without by the
cones as they were forming, — a process which resulted in a
thrusting-aside vertically of the enveloping layers, in a manner
often observable in connexion with Coal-Measure nodules, and
with nodules of marcasite and pyrites in coal.
Digitized by Google
Vol. 50.] * DBT05IA5 ' 8ERI~E8 IN PEOTT8TLYANIA
737
(7) The phenomena of the corrugated and wrinkled surfaces, both
upon the sides and the bases of the cones, the dark clayey
lateral ridges or rings encircling the cones, and the serrations
upon the bases of the cone-layers, all appear to indicate unmis-
takably the operation of lateral radial contraction, squeeze, or
pressure acting towards the centre of the formations.
(8) Further, an inspection of the minuto texture of the walls of the
cones reveals a semi-crystalline structure, — namoly, innumerable
aggregates of miniature or semi-microscopic cone-in-cone com-
parable with the main structure.
(9) Thus the conclusion is reached that cone-in-cone must be regarded
as a species of concretion, whose peculiar mineral and chemical
composition induced such pressure among the particles while
undergoing transformation as to produce the forms of cones
and (by differentiation) parts of cones all through the separate
layers, collectively and yet independently.
In other words, this cone-in-cone is a final product of the
concentration of calcium carbonate around certain nucleal
points within, or horizontal planes of original stratification of,
detrital sedimentary fossiliferous rocks; which accretionary
process involved the partial expulsion of the non-crystallizing
contained clayey material, and this material, seeking or
struggling, in obedience to the laws of crystallization, to
escape, was perforce (owing to close confinement all around,
with ever-increasing contractile inward and radial pressure
tending to keep it back) compelled to assume the form of
horizontal rings or ridges : and these were the weakest places
which the pressure-produced conic cleavage afforded. The cal-
careous semi-crystalline fabric of cones having completed its
mutations or gone through the requisite evolutions, with the
argillaceous rings of squeeze brought into equilibrium with
the rest of the structure, cone-in-cone was complete.
Finally, the observed structures in the typical Portage cone-
with the cone-in-cone of the Coal Measures in Great Britain
and in North America, impel the prosent writer to regard the
origin and formation of one and all as practically identical in
original composition— chemically and physically,1 and, in the
main, to accept the conclusions of other observers in this con-
nexion, who consider the formation to be a result of pressure
acting upon concretions.
1 Many examples of cone-in-cone, as they exist to-day, are unquestionably
what may be called re-altered products— that is, * tertiary ' formations ; for the
author's collection contains oone-in-cone composed of haematite, limonite, fer-
riferous quartxite, quartrite, pyrites or mareasite, and a variety of more or less
iron-impregnated siliceous rocks.
738 MR. W. 8. GRESLEY ON CONE-IN-CONE IN THB [Nov. 1894,
EXPLANATION OF PLATES XXXV. & XXXVI.
[All the specimen*, unless otherwise stated, are from the Portage Flags
(Devonian ?) of Erie, Pennsylvania.]
Platb XXXV.
Fig. 1. Photograph of an exposure of a typical mass of • cone-in-oone ' if* situ in
the cliffs of the southern shore of Lake Erie, 2 miles N.B. of the city
of Erie, exhibiting a transverse section of the formation occurring near
the middle of the Portage Flags.
Fig. 2. Diagram uiatio view of the conic mass in fig. 1, showing the chief charac-
teristic features (stratigraphical and structural) of the several layers
of cone-in-cone in relation to the central sandstone or nucleal band,
above and below which the cones point in opposite directions.
Fig. 3. A perfect or typical cone ' a,' encircling which are several portions of
cone-in-cone structure or conic scales, ' b,' • c,' ' d,' which shows the
relative position of the parts or structure of the formation, as revealed
in any one or all of the different layers of cones pervading the conic
masses in fig. 2.
Fig. 4. Portion of a conic cake in contact with, and having tongues or offshoots
of, the cone-formation running into the nucleal stratum.
Fig. 5. Portion of a cake or layer of inverted cone-in-cone, through which
posses a thiu stratum of dark argillaceous shale between two lighter-
coloured layers of similar material, the dark band being thicker where
it has become 4 cone-in-conixed.'
Fig. 6. Portion of an inverted layer of cones, next to a thin bed of calcareous
sandstone : this specimen, on weathering, hat split along the bedding-
plane separating the cones from the sandy layer.
Fig. 7. A small portion of the bases of cones and conic scales of a typical layer
of the formation, exhibiting the characteristic corrugated or differ-
entially wrinkled surfaces, as well as the curvilinear fines which are
the divisional planes of the cones. There is also seen a small conical
depression, and two or three little conical peaks.
Fig 8. Transverse suction of cone-material between well -developed cones (not
shown), illustrating the wrinkles of the bases of the cones, and the
continuation of the wrinkling down the surfaces of the conical
hollows in which the cones occur.
Fig 9 Perspective view of part of a conic cup (cone removed), showing the
differentially wrinkled surface referred to in flg. 8, increasing in sue
and strength towards the rim.
Figs. 10 & 10a. View of a good cone (fig. 10), showing how its surface is ringed
horizontally with irregular flounce-like appendages of fibrous cal-
careous material, which die away to mere streaks as the apex of the cone
is approached. Fig. 10 a shows two of these rings in cross section,
magnified about 5 times.
Fig. 24. One of the numerous dark specks (? an organism) promiscuously scat-
tered through the cone-in-cone layers, and seen outside them also
(see figs. 7, 15, & 21), magnified 10 ti
Platk XXXVI.
Fig. 11. Diagrammatic view through a complete cone, exhibiting the connexion
between, or the relative positions of, the corrugated surfaces shown in
figs. 7, 8, 9, & 10, and the intervening clayey material (black) en-
circling the cone.
Fur 12 Enlarged view of a portion of the right eide of the conic scales enclosing
' the cone of flg. 11, showing the feathery or splay-shaped arrangement
of coue-in-cone structures lapping around one another, and separated by
the calcareous and the non-caluireous rings (see PL XXXV. flg. 10a,
and the black portions of PI. XXXVI. flg. 11), magnified 4 times.
Figs. 13 & 13a. Diagrammatic view and plan of base, respectively, of a strong
cone, encompassed by typical structure (shown in figs. 7-12 inclusive),
Digitized by Google
Quart. Journ. Geol. Soc. Vol. L. PI. XXXV.
W. 8. Qrealcy deL et photogr.
CONE-IN-CONE.
Quart. Journ. Geol. Soc. Yol. L. PI. XXXVI.
W B. Orcalcy del. et photogr.
23
CONE-IN-CONE.
Google
Vol. 50.]
• DEVONIAN ' SERIES IN PE5KSYLTANIA.
739
but giving prominence to the curved ridges of clayey material stickiu*
out around the rim of the cone in a manner suggestive of vertica*
or lateral squeezes amongst the cones.
Fig. 14. Transverse section (polished surface) of an nbnormal development of
the horizontal dark clavey rings of figs. 11-13, showing a fibrous or
laminated structure. From the Lower Productive Coal Measures,
Beaver Falls, Western Pennsylvania.
Fig. 15. Slightly magnified portion of a micro-slide of Portage cone-in-cone
(inverted layer), exhibiting miniature faulting in a dark layer of sedi-
ment passing through the conic cake. The dark spots are various
portions of the same form as that shown in PI. XXX V. fig. 24. From
Northeast, Pennsylvania.
Fig. 10. Much reduced drawing of parts of three heights of inverted cone-in-
cone affected by a local swelling (a concretionary ridge?) of the
central or nucleul stratum of the conic mass of which they form a
portion. This also shows slight faulting of the cones, clearly a result
of lateral pressure in connexion with the swelling above. Reduced
about 8 times.
Fig. 17. Cone-in -cone, with truncated apices.
Fig. 18. Conic scales, somewhat distorted, with their apices bent backward and
disarranged.
Fig. 10. Horn shaped cone-in-cone, with slickensided surfaces.
Fig. 20. View of a complete cone, looking at its apex, showing the arrangement
of the pointed ends of the component conic scales forming the apex.
Fig. 21. Markings on the polished surface of a transferee section of a good
cone, about A inch from the base of the cone. This shows the compo-
nent conic structure and some of the dark specks (see PI. XXXV.
fig. 24).
Fig. 22. Perspective view of a bit of argillaceous shale, on one flat surface of
which a singular concentrically-arranged scalariform structure of the
Bfime shale was rerealed. This may poasibly represent the impression
of the base-surface of part of a layer of cone-in-cone.
Fig. 23. Reproduction from a photograph of part of two inverted conic cakes
s"en in cross fracture. The upper layer of cones is much confused,
crumpled and slieken«itled. A thin band of calcareous sandstone
separates the two layers of cones.
Q. J. G. S. No. 200. 3 e
Digitized by Google
GENERAL INDEX
ID
THE QUARTERLY JOURNAL
AND
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
[The Fossils of which tho names are printed in italics are figured.]
Abberlev Hill, Permian breccias of,
464, 4&L
Abbott. W. J. L.. on Qs^frrous Fis-
sures in Shode Valley no^r Igbt-
ham, 171 .
Additions to the Library. Pro**. 151.
Africa, Equatorial East, isobaric map,
520.
Africa, South, occurrence of dolomite
in, 501.
Africa, South-eastern, geology of, 548,
& pis. xxi.-xxii. (sections).
4 Akerites,' £L
Alaska, mammoth-remains in, L
Ahutda arvrnsis, 10J & pi. x.
Aleutian Islands, mammoth-remains
on tho, 4, 8, 2.
Alford, C. J., on auriferous rocks from
Mnshnnaland, Proc. JL
Alluvial deposits in Matto Orosso. 22.
Alps (CottiaiA Waldensian gnei.wes
etc. in the, 232 : (Lepontine), Me-
sozoic rooks and crystalline schists
in the, 23iL
Altkirche (Switzerland), marble of,
287 ; section at, 2X8,
Ammodiwnis cbaroides, 000 ; A. gor-
dialis. 000 : A. incertus, 000; A.
pleurofomarfoules, 007 & pi. xxxiv.
Ammonites (Stephanoceras) subar-
matus, Proc. ±.
Amphibolites near Porrero, etc., 254,
Anas boscas (?), 121 & pi. x.
Anderson, Sir J., obituary, Proc. 44.
Andesites near Builth, 510.
Andesitic ashes near Builth. 57 1 .
Andrews. Rev. W. R., & A. ,L Jukes-
Browne, on the Purbeck Beds of
the Vale ot Wardour, 44-
Angrogna Valley (Italy), 250.
Aiujuis frctf/ilis, UK) & pi. x.
Annual General Meeting, Pror. 12,
Anomalina ammonoides, 722 ; A. ari-
minensis, 722; A grosserugosu, 723.
Anthrjcomya arrnacea. 440 «fc pi. xx. ;
A. elmfiata, 44Q k pi. xx. : A. l/tois,
441 & pi. xx. ; A. oiyi/m. 441 <fc pi. xx.
Anthracoptera, name discarded for
Xaiadiies, I'.iS.
Anthracosia, later name than Car-
bon icoia, 441
Antu-lin.il folrls in Libyan Desert, iiv
relation to water-supply. 5.17.
Aplite in Gcrrardo Volley, etc. 247.
2"i0 ; aplite-veins in 'pietre verdi,'
257 & pi. xv.
Apus, structuro compared w. trilo-
bitic, 412 et seqq. ; diagram of eye,
42L
Apus (Ispiilurun) spifzbcrgensis, sec-
tions through, 427, 428_
Arnra Limestone, 01.
Archu^onisctis - limestone, diagram
showing variations of strata be-
tween it &. Cinder-bed, 57.
Arctic regions, suowdrift deposits in,
47JL
Argentina, fo3sil vertebrates from,
Prjc. 146.
3e2
742 GE5ERJ
Arkansas novaculites, 377 tt teqq.
A mold -Bern rose, H. 11., on Micro-
scopical Structure of Carboniferous
Doh-ntes k Tuffs of Derbyshire,
W3 pis. xxiv.-xxv.
Artesian boring near Windsor Forest,
152, 490.
Ash, vjleanic, metatnorphisra of, 356
Ct S(l/Q.
Ashover (Derbyshire), tuff, 639.
Ashpriufefon Volcauic Scries, Proc. 73
ct -"cqq.
Audit ore elected, Proc. 6.
Augite, causes of change into horn-
blende. 355, 359; in Derbyshire
lavas, 621.
Augite-diorite veins in pyroxenitc of
Brandberget, 32.
Augite-porphyrite dykes near Solvs-
berget, 34.
Augite-svcnite in Mntto Grosso, 100.
Austin, C. EM obitunry, Proc. 44.
Australia, Upper Carboniferous
boulder-beds of, 4(18.
Aveline. W. T.. Murchison Medal
awarded to, Proc. 35.
Babnria Oasis (Libyan Desert), 532,
535 ct «V7,
Banded gnbbros in Skye, 217 & pi.
xiii., 645 & pis. xxvi.-xxviii.
Barbate limestone in Culford boring,
495; Bargnte Beds of Surrey &
their microscopic contents, 077 &
plB. xxxiii -xxxiv.
Barge (Italy). 258.
Barlow-Jameson Fund, list of awards,
Pn>c. 25 ; award to C. Davison,
Proc. 39.
Barnton (Midlothian), picrite at, 30;
section along railway, 39.
Barrow, O., Murchison Fund award
to, Proc. 36.
Basalt near Bathurst (N.S.W.), 116
with analysis.
Basicity of gabbros. relative, tested by
specific gravities, 321.
Bathurst (N.S.W.), geology of, 105;
map & section, 108, 109.
Bathynotus holopygia (?), 671.
Beaufort Beds in S.E. Africa, 553.
Beeher, II. M., obituary, Proc. 51.
Beneden, P. J. van, obituary. Proc. 56.
Bernard, II. M.. on Systematic Posi-
tion of the Trilobites, 411.
Berrow Hill, Permian breccias, 465,
407.
Bigsby Medallists, list of, Proc. 25.
Bird Reef Series conglomerates,
Proc. 5.
INDEX. [NOV. 1894,
Birmingham, snowdrift deposits seen
at, 474.
Bison prisous from Twickenham, 456,
458.
Black-garnet schists in Lepontine
Alps. 298 ct *cqq.
Blomefield. Kev. L., obituarv 'Proc. 50.
Bolivina dilatata(?). 704; 'B. textila-
rioide*, 704.
Bolton. H., on a Goniatite from the
Lower Coal Measures, Proc. 145.
Bouncy, T. G., on Conversion of com-
pact 'Greenstones' into Sehitta,
279; on Mesozoic Rocks & Crystal-
line Schists in Lepontine Alps, 285 ;
& Mips C. A. Raisin, on Relations
of older Fragmental Rocks inS.W.
Caernarvonhhire, 578.
Bony sen E*tate (Witwaterarand),
boring on the, Proc. 5.
Borings, table of, in London Basin,
513.
Bos longifrons (?) from Twickenham,
456, 458, 461.
Boftonites in Gran district, 23 ; ana-
lyses, 2l>, 27.
Boulay Bay (Jersey), devitrified ob-
sidian, 12 «fc pi. i.
Boulders found in coal-seams, Proc.
63.
Boulder-beds, Upper Carboniferous,
of India and Australia, 4<>8.
Boulder Clay, at Barnton, 39 ; in
Romford dixtrict, 446 ct wjq. ; rela-
tions to Thames Valley Beds, 44S.
Brandberget (Norway ),olivine gabbro-
diabnse. analyses, 19, 20; pyroxenite,
analysis, 31.
Breccias, Permian, of England, 463.
Brent Tor (Devon) rocks. 360.
Brodie, Rev. P. B., on Discovery of
Molluscs in Upper Keuper at
Shrew ley. 170.
' Broken Beds ' (Purbeck) equivalent
in Wilts. 50.
Brook Bottom (Derbj-shire), 611 ;
tuff, 626.
Bryozoa. *ce Polyzoa.
Jiufo vulgaris, 190 & pi. x.
Builth (Radnorshire), igneous rocks
of neighbourhood, 566; geological
sketch-map of district, 5(>8.
Bulimina aflinis, 702 ; B. brevis, 703;
B. Murchisoniana, 703 ; B. obliqua,
702 ; B. obtiusa. 703 ; B. ovata. 7(>2 ;
IS. polyttropha, 701 & pi. xxxiv. ; B.
Presli, 703 ; B. pupoides, 702 ; B.
pyrula, 702.
Buschbad (Saxony), perlitic obsidian,
12 4 pi . i.
Bu^soleno (Italy), 245; map of
Digitized by Google
Vol. 50.]
GENERAL INDEX.
74.J
district, 240 ; Waldensian gneiss
from, pi. xv.
Bidto (?), im & p). x.
Caernarvonshire, Cambrian and pre-
Cumbrian in, Proc. oJJ et set/q. ; re-
lations of older fragmental rucks in
N.W., 578.
Calatnophyllia fenestrata, 305. 306.
Ca lea ire du Brianconnais, 3U4. 3 1 0.
Calymcnc Blumenbachii, pygidium,
424 ; C. senuria, sections through,
427,428.
Cambrian rocks, papers on, summa-
rised, Proc. 8z.
Cambridge, snowdrift deposit seen at,
im
Camptonites in Gran district, 23 ;
analyses, 26, 27.
Cants lagopus, 202 k pi. xii. ; C. vul/>es,
2U1 k pi. xii.
Capreolus caprea, 109.
Carbonicola (Antkracosia) angulata,
Ml & pi. xx.
Carboniferous (?) in Matto Grosso, 9_7_;
(Upper) boulder-beds of India and
Australia, 408; dolerites k tuffs
of Derbyshire, microscopical struc-
ture of, tMKi k pis. xxiv.-xxv.
Carboniferous Limestone, papers sum-
marized, Proc. 71.
Carrock Fell, gabbro of , 3J. 1 & pi. xvii.;
map, pi. xvi. ; section across, 3LL
Curyehiuiu minimum, 184.
Cassidulina subglobosa, 704.
Castleton (Derbyshire), tutf, 625.
Catherine Ford (Wilts) section de-
scribed, 61.
Cave-sandstone in S. Africa, 55 1 .
4 Central gneiss,' in Cottian sequence,
233 ei *eqq.
Cervus elaphus, LQiL
Chaberton, Monte, geology of, 3U'l ;
map of, 301) ; section through, 310.
Chalk, Lower, inCulford boring, 4ii3_;
M. Ln k U., in Wiukfield boring,
4'J7. iiilL
Chaunel Islands, papers on the, sum-
marized, Proc. 1 3S*
Chapada Sandstones, 115_,
Cliapman, F„ on Bargate Beds of
Surrey k their Microscopic Con-
tents, OH k pis. xxxiii.-xxxiv.
Charlesworth, E., obituary, Proc. f.
Cbeilo»tomnU>us polyzoa in Inf.
Oolite of Shipton Gorge, 12. k pis.
iu-iv. ; in Middle Lias of King's
Sutton, 7J1 & pl». v.-vii.
Chert, in Brazilian Limestones, 02 ;
compared with novae ulite, 376 crl
.vryr/. ; with sponge-spicules, from
Butlth, 573.
Chesbunt (Herts), boring near, 50-S ;
samples from, described, MKL
Chilmark (Wilts), section described,
48.
Ohilworth (Surrey), Bargate Beds
near, 681.
Chisone Valley (Italy), 25L
Christ iania (Norway), geological map
of district, liL
Church Hill, Permian breccias of,
464. 465.
Cinder-bed, diagram showing varia-
tions in strata between it k Archae-
oniscus-limestone, 57.
Cistemifera clausa, gen. et sp. now,
82 k pi. vii. ; C. inconstana, sp. nov.,
80 k pi. v. ; id. forma prima, SJJ k
pi. T.; id./or7«asfcti«rfa, 81& pi. vi.;
id. forma tertia, 82 & pis. v., vi. ;
id. forma quarta, 82 k pi. vi.
Clastic gneisses, 265. 206.
Clent Hills, Permian breccias of, 464.
466.
Clos des Morts Valley, sections, 305 ;
Clos des Morts Limestones, 304
et xeqq.
Coal in S.E. of England, Proc. 6JL
Coal Measures at Litbgow (X.S.W.),
115.
Coal Measures, Nova Scotian, Naia-
dites from, 435 k pi. xx.
Coal-seams, boulders found in, Proc.
63 ; wash-outs in, Proc. 64. ; for-
mation of, Proc. 65 ; marine fossils
in, Proc. 6^ 6j ; coal-seams in Mol-
teno Beds of S.E. Africa, 552.
Cock's Tor (Devon), volcanic ash, etc.
of, 35L25Z
Col de Vento (Cottian Alps), 240 ;
map of gneiss exposures, 251.
' Complementary rocks ' defined, 3.L
Composition-fee raised, Proc. 150.
Concentration-hypothesis of minerals
in gabbro, 327.
Cone-in-cone in Devonian (?) of Penn-
sylvania, 731 k pis. xxxv.-xxxvi. ;
cones, inverted, 731 ; double cone-
in-cone, I3JL
Coniact-metamorphism along boun-
dary of olivine-gabbro-diabases of
Gran, 21 ; produced by Bathurst
granite. 111, 117 ; in Cottian Alps,
261, 262 ; co 11 tact- rocks from Os-
tana, pi. xv. ; contact-phenomena
in Carrock Fell gabbro, 331.
Cordilleran Glacier, 5.
'Corduroy ' structure in metamor-
phosed tuff, 352i
GENERAL IN HEX.
[XoY. 1894,
* Corrie' glacier*, 515.
Corstorphine HiJl (Midlothian), dole-
rite, 42.
Corumbu Limestones, 91.
Cotham Marble, description of cha-
racter*, mode of occurrence, fc for-
mation, 31)3; theories » s to origin,
399 ; experiments' reproducing, 405.
Cutman's Ash (Kent), section to Shin-
gle Hill. 174; section along Shode
Valley to l'laxtol, 175.
Cottian* Alps, described, 232; the
Cotttan Sequence, 234.
Council, report for 1893, Proc. 10;
k officers elected, Vroc. 17-18.
Craeknowl House (Derbyshire), tuff,
032.
Cretaceous (?"> in Mntto Grosso. 98 ;
in Monte Chaberton area. .'00; in
Libvan Desert of Egvpt, 534.
Crissolo (Italy), 258.
Cris-tellaria acutauricularis, 713 ; C.
Bronni, 713; C. eomplanata, 712;
C. conTergene, 714 ; C. crepidula,
712; C. cultrata, 714; C. cvm-
boides, 713 ; C. gibha, 714 ;' C.
grata. 713 ; C. itilica, 712 ; C. laevi-
gata, 713; C. megalipolitona, 714 ;
C. oligostegia. 713; C. parallela,
712: C. prominula, 714; C. rotu-
lnta, 714; C. Schloenbacln, 712;
C. suleifcra, 712; C. tricarinella,
711 : C varians, 715; C. vestita, 71 1.
Crusskey, H. W., obituary, Pnr. 52.
Croxdale Colliery, dyke in coaK*eam
at, Vroc. 3.
Crystalline schists, papers on, mm-
marized, Proc. ic2 ; in the Lepon-
tinc Alp?, 285.
Cultord (Suffolk), deep borir.g at, 489 ;
description of samples, 491 ; classi-
fication of beds, 493.
CuyabA (brazil), section to Tapira-
punin Hills, SI).
Cuvabi Slates, 90.
•
Cvpris fasciculatn, determining base
'of Middle Purbeck, 54.
Cythcre rdicostata, sp. nov., 106 &
pi. ix. ; C. vctictilosti . ej>. nov., 088
& pi. xxxiii.; C. ll'ikoni, sp. nov.,
1«7 & pi. ix. ; C. sp.?, 107 & pi. ix.
Cyt hems Lomdaleana, 089; C.ornati*-
eima, 088; C o. var. reticulata, 089.
Cythcridta ellipsoid ra, 104 & pi. ix. ;
C. bicarinata, 090 ; C. b. var. v»du-
lorn, nov., 090 A pi. xxxiii. ; C. f'ipa-
jrtlfata, tip. nov., 091 & pi. xxxiii. ;
C. craticula, 090 ; C fcnentrata, pp.
nov., 090 <fc pi. xxxiii. ; C. Mooni,
sp. nov., 105 & pi. ix. ; C. retorrida,
689 ; C. rotundata, 0S9 ; C. *ubper-
forata, 089; C. vellicota. sp. nov.,
090 & pi. xxxiii. ; C. sp., 106 &
pi. ix.
Cythtropteron Brodiei, sp. nov., 107
& pi. ix. ; C. eoneentricuin. 091 ;
C. c. var. virginea, 1 11 » 1 ; C. co*t»li-
ferum, sp. nov., 092 L pi. xxxiii. ;
C. drupaceum, 091 ; C. laticruta-
tum, 092 ; ('. rrficufotuM, *p. nov.,
092 i.pl. xxxiii.; C.subconcentricuin,
091.
Dakhla Oasis (Libyan Desert), 533
et *rqq.
' Dark loam layer ' (Pleistocene) at
Twickenham, analysis, 457.
Dan moor granite, Proc. 127 et *rvq. ;
trachytes, metamorphosed tuffs, &
other rocks of igneous origin on
W. flank of, ,'!38.
Darwin ula ylulmsa, 103 & pi. ix. ; D.
yl. var. stricta, nov., 104 h, pi. ix. ;
D. /i<t.*sica, 102 & pi. ix. ; D. I. var.
mtijor, nov. 1<>3 & pi. ix.
DavicH, A. M.. & J. \V. Gregory on
geology of Monte Chaberton, 303.
Davis. J." W., obituary. Proc. 44.
Da\ison, C, Barlow-Jameson Fund
award to, Proc. 39; on Deposits
from Snowdrift, with especial refer-
ence to Origin of Loess & preserva-
tion of Mammoth-remains, 472.
Dawson. G. M., on the Occurrence of
Mammoth-remains in Yukon dis-
trict of Cannda and Alaska. 1.
D»«w>on. Sir J. W., on Xaiadite* in
Coal-forination of Nova Scotia, 435
& pi. xx.
Denton, J. B., obituary, Proc. 52.
Derbyshire, microscopical structure of
Carboniferous dolerites & tuffs,
Ot 13 A. pis. xxiv.-xxv.
' Detntal quart xites,' 380.
Devonian of Bsthurst (N.S.W.), 114 ;
('") of Pennsylvania, cone-in-cone in,
731 k pis. xxxv.-xxxvi. ; in Matto
G rosso, 95; the succession in S.
Devon, Proc. 74 et seqg.
Devonian Limestones of 8. Devon,
microscopic structure of, Pro?. 72.
Diabases of Carrock Fell, 313 ; of
Builth district, 574.
Dinbase-porphyrite of Builth district,
507.
Diantopora, ao-cailed, 83 & pi. v.
Differentiation of common magma
originating various eruptive rocks
in Gran district, 20, 31, 35; the
same contrasted with differentiation
described at Carrock Fell, 320;
differentiation in situ, 050.
Digitized by Google
Vol. 50.] GEXER
Dignues (Norway), olivine-gabbro-
di abase, analysis. 10, 20.
Dinton (Wilts ),8ectiond near.deseribed,
50, 58, 50 ; sections along railway,
1) orite, auriferous, Proc. 9.
Di^corbina araucana, 721 ; D. Berthe-
loti, 720 ; D. B. vur. Baeouica, 720;
I) concinna, 72^; D. obtusa, 720;
J), orbicularis. 7 1 i * ; 1). parUiensis,
710; D. pileolus, 710; D. rosacea,
710 : I), ruga*, 720 ; D. turbo, 710 ;
D. Yilardeboana, 721.
Pistliene-schists in Lepontine Alps,
2i»7 tt *rqq.
Ditch Cliff (Derbyshire), 610.
Dolerite-vein in Barn ton picritc, 42;
dolerite of Coratorphine Hill, 42;
of Tapirapuam (Brazil). 100; al-
tered, of Brent Tor, 301 ; dolerite
associated with Dwyka Conglome-
rate, 655; Carboniforous doleritcs
of Derbyshire, microscopical struc-
ture of, 603 & pis xxiv. xxv.
Dolomite, suggested replacement by
silica, 381, 380, 564 ; occurrence in
South Africa, 661 & pi. xxiii. (sec-
tions).
Dorking (Surrey), section on Horsham
Road described, 6S7.
D ive Holes (Derbvshire). 610; tuff,
620.
Dnikensberg range (S.E. Africa). 548;
diagrammatic section of, «t High
Veld plateau, 660 k pi. xxii. ; sec-
tion from Mont aux Sources to St.
Lucia Bay, pi. xxii.
Draper, ])., on Geology of S.E. Africa,
548 & pis. xxii. -xxiii. (sections) ; on
Occurrence of Dolomite in S. Africa,
561.
Drift near Bathurst (N. S. W.), 116.
Druim an Eidhne (Skye), relations of
gabbro and granophyrcs, 216 ct
M^y. ; banded structure of Tertiary
gabbros, (»46 A pis. xxvi.-xxviii.
Dust (of snowdrift deposits), origin
&. transportal, 477.
Dwvka Conglomerate in S.E. Africa,
554, 550.
Kartb-morements m the Cottians. 271 ;
of Monte Cliuberton, 308; at Wadi
Haifa, etc., 546 647.
Keen Beds in S.E. Africa, 554.
^Uards, D. T., on Boring on the
Booysen Estate (Witwatersrand),
1'roc. 5.
Egge (Norway), analyses of ca nip-
ton ite from. 26, 27.
Egypt, stratigraphy and physiography
INDEX. 745
of Libyan Desert, 531 & pi. xxi.
(map).
Ehrenbergina pupa, 704 & pi. xxxiv.
•Elephant-rock in Transvaal, 561,
502.
Elephos primigenius (?), 108.
Ember Line (Derbyshire), dolerite
& tuff. 632.
End»lcigh Street Beds, position dis-
cussed, 452.
Eo-ene in Libyan Desert of Egvpt,
534.
Epidiorite, porphvritie, of Sourtou
Tom, 340 ; of Cock's Tor, 368 : of
W. Dartmoor, origin discussed, 305.
Equus ciballus, 108.
E-tllieria Dawsoni, 437, 430.
Evans, J. \\\. on the Geology of M »tto
G rosso (Hrazil), 85&pl. viii. (map).
Exogyra Overwegi-series in Libyan
Desert, 534, 535.
Eveott group in Carrock Fell district,
"313, 315, 331.
Farafra Oasis (Libyan Desert), 535
540.
Fellows elected, Proc. 1,2, 3, 4, 5. 8,
141, 142, 143, 144, 145. 147, 14** ;
number of, Proc. 14 ; names read
out, Proc. 148.
Felsites of Sourton Tors. 313; in
N.W. Caernarvonshire, 570 ft *roy.
Felsilic dyke in gabbro, Druim an
Eidhne, 226.
Felspars in Derbyshire lavas, 622.
Financial report, Proc. 26.
Flint compared with Arkansas stone,
37H rt seqq. & pi. xix.
Fluxion-gneisses. 267.
Foraminil'era of Lower Greensand,
08*; from Bargate Beds, 603 &
pis. xxxiii. -xxxiv. 726
Foreign Correspondents elected, Pn>c.
1. 4, 143, 147 ; list of, Pr>>c. 20.
Foreign Members elected, Pw.4, 143,
1 48 ; list of. Prttc. 19.
Foresto di Susa (Italy), section to
Gerrardo Valley, 248.
Foxes' bones, measurements of. 202.
Frondicularia brizaformis, 700 &
pi. xxxiv.
1 Fundamental rocks/ papers on,
summarized, Proc. 93.
Furka Pass, section at summit, 205.
Gnbbro bosses in Western Isles (Scot-
land), 216 ; relations w. granophyre
in Skye, 216 et stqi/. ; banded. iW.,
2l7&*pl.xiii..645& pis. xxvi.-xxviii. ;
chemical analysis of same, 653 ;
coarse and massive variety, 6 10,
Digitized by Google
746
GENERAL INDEX.
[Nov. 1894,
Oil ; granulitic variety, 647. 650 ;
pale reins, 650. 054 ; gabbro of
Carrock Fell, Mi k pU. xvi.-xvii. ;
mineralogical characters of tame,
310. 319 ; orderly variation from
centre to margin, 320 ; chemical
analyses of aame, 323 ; causes of
variation, 324 ; lava-masses enclosed
in, 315, 33J. ; tnetamorpbism by
g ranophyre, 334.
Gaud ry ina bnccata, 7DQ ; G. filifortnis,
Uil ; G. pupoides, 700.
Gault in Winkfield boring, 499: in
Ware boring, 507.
Geikie, Sir A., on Relations of Basic
& Acid Rocks of Tertiary Volcanic
Series of Inner Hebrides, 2L£ k
£ls. xiii.-xiv. ; k J. J. IL Te«ll, on
anded Structure of Tertiar}- Gab-
bros in Skye, 645 k pis. xxvi.-xxviii.
Gerrardo Valley (Iialy), 240, 247;
section, 248.
Glacial origin of Carboniferous boul-
der-beds in India k Australia, k of
Permian breccias of England, 400 ;
glacial geology of Mount Kenya,
515;*glacial boulder-clay,' so-called,
in S.E. Africa, 554.
Glaciatiun, limit of, in N.W. America,
5; no evidence in S.E. Africa, 558.
Globigerina bulloides, 710.; G. cre-
tacea, 718.
Gneis8e8tWaldensian. 232. 239 ; sketch-
map of distribution of name, 238 ;
gneiss k limestone junction at Col
de Vento, 249 ; ' pietre verdi ' in-
clusions in, 242, 25J1; origin of
gneissic structure, 264; classification
proposed, 266 ; structure and origin
elucidated by banded gabbros, 657.
Gudalming (Surrey), clay-seams in
Bargate Beds at. 687.
Gold in the Witwatersrand Series,
origin of, Proc. 60^
Gold-bearing rocks from Mashonaland,
Proc. 8 ; quartzite from Nondweui,
38S, 389; dolomite of Malmani,
503, 5_Ga.
Gold-deposits in Matto Grosso, with
analysis of matrix-rock, 102. 103.
Goniatite from Lower Coal Measures,
Proc. 14;.
Gosau Beds of Gosau district, ' 1211 ;
map, 120 : paljeontology, 13_±; geo-
logical horizon, 13_7_ ; correlation w.
English Upper Cretaceous, 147 ;
physical history of, 147.
Gran (Norway), basic eruptive rocks
of, 15. ; map of district, II*
Grange Mill (Derbyshire), tuff1, 632,
Granite of Bathurst (N.S.W.), 107,
110; on South Down (Devon), 350;
hornblendic, of Jebel Abu Bayan,
532.
Granopbyre in Skye, relations with
gabbro, 21Q et seqq. ; granophyre-
dyke intersecting banded gabbros,
pi. xiv. ; granophyre of Carrock
Jell, 312 et *eqo. ; same metamor-
phosing gabbro, 334.
Granulitic gabbros of Druim an Eidhne,
047,
Graptolite-zones, Proc. 79.
Gravels near Bathurst (3i. S. W.), 110.
Greensand, Lower, in boring near
Windsor Forest, 152, 496 et seqq.;
in Culford boring.403. 495j (Upper)
in Winkfield boring, 498, 499 ; os-
tracoda k foraminifera of the, 088.
Greenstones, compact, conversion into
schists, 279.
Gregory, J. W., on Waldensian Gnei sses
k their place in the Cottian Sequence,
232 ; on Glacial Geology of Mount
Kenya, 515 ; k A. M. Da vies, on
Geologv of Monte Chaberton. 3< )3.
Greisen of Carrock Fell, 313, 314,
Gresley, W. S., on Cone-in -cone in
Devonian (?) of Pennsylvania. 731 k
pis. xxxv.-xxxvi.
1 Ground-ice ' formation in Alaska, 3,
fi.
Griim Alp (Engadine), 27JL
Guildford (Surrey), Bargate Beds near,
678.
Halfpenny Lane (Chilworth), sections
of Bargate rocks from, 682. 684.
• Hanging ' glaciers, 515.
Haplnphragmium acutidorsatum, ( 'P.~> ;
JEL agglutinans, Ollii ; LLdepressmn.
695 ; IL emaciatum, 694 , IL iolia-
ceum, 624 ; IL H u m bold ti. 694 ; IL
irregulare, 004 ; IL neoi'omianHm,
sp. nov., 695 k pL xxxiv. ; IL uonio-
ninoidce, 695.
Harker, A., on Gabbro of Carrock
Fell, 311 k_ pis. xvi.-xvii.
Hartebeest Fontein (Transvaal), sec-
tion to Vredefort, 560 k pi. xxiii.
Haslemere (Surrey ), section to Maiden-
head, 154.
Hnwksley, T., obituary, Proc. ±3.
Hebrides (Inner), relations of basic k
acid rocks of Tertiary volcanic
series, 212 k pis. xiii.-xiv.
' Herring-bone ' structure in pyroxene.
High Veld Plateau (S.E. Africa), 549j
section, 560 k pi. xxii.
Highlands, N.W., physical relations &
post-Cambrian metamorphism of
rocks in, Proc. 83 ; additions to fauna
Vol. 50.]
GENERAL INDEX.
747
of Ofmelltis-toae, GQ1 St pis. xxix.-
urn
XXX11.
Hill, W., Lyell Fund award to, Proc.
38.
Uippurite-limestone in Gosau district,
128. 132.
Hohnel, Mount & Lake (Equatorial
East Africa), MIL
Holloway Hill(Godalraing),clay-seams
in Bargate Beds at, 6-S7.
Holmes, T. V., on Sections on "Romford
& Upminster Kail way, & Relations
of Thames Valley beds to Boulder
Clay, 443.
Holmia Kjentlfi, 67_1 & pi. xxxii.
Hopton (Derbyshire), tuff, B3A
Hornblende in camptonites, 29.
Hornblende-schists of Lizard compared
with Cock's Tor rocks, 355 et aeqq.,
3f>4.
Hospenthal (Switzerland), section de-
scribed. 29-2.
ITospenthal schists, 287 et seqq.
Hudleston, W. H., addresses to Medal-
lists, Proc. ji et seqq. ; obitunries of
deceased Fellows, Proc. £i et seqq. ;
president ial address on Recent Work
of the Geological Society, pt, ii.,
Proc. <;8.
Huken (Norway), analysis of labrador-
porphyrite, 33.
Hull, £., on an artesian boring at New
Lodge (Windsor Forest), Berks. 152-
Hurst Wood (Kent), section to Shingle
Hill, 124.
Hyttna crocuta (?), 201 & pi. xii.
Hypersthene, analysis of, 22.
Ice- formation, underground, origin of,
4S5.
Iddingsite, differentiated from Potluck
pseudomorphs, 617_ et xeqq.
Ightluun (Kent), ossiferous fissures
near, 171 ; vertebrate fauna f rom
same, 1M & pis. x.-xii. ; table of
distribution of vertebrata, 203.
India, Upper Carboniferous boulder-
beds Of, 4(iM
* Infiltration (luartzitea,* 380.
Insect-bed in Vale of Wardour Pur-
becks, &L
Iron-ores in Matto G rosso, 98, 00,
103; near Wadi Haifa, 534.
Isobaric map of Equatorial East Africa,
52k
Isopods, in relation to trilobites, 4 .'32.
Jebel Ahmar Sandstone, 537, 541.
Johnston- Laris, IL J., Enclosures of
Quartz in Lara of Stromboli, etc., &
Changes in Composition produced
by them, Proc. 2,
Jones, T. R., on Rhrctic and some
Liassic Ostracoda of Britain, 15ii Jc
pi. ix.
Jukes-Browne, A. J., & Rev. W. R.
Andrews on the Purbeck Beds of
the Vale of Wardour, 44; & W.
Whitaker, on deep Borings at Cul-
ford aud Winkfleld, with Notes on
those at Ware and Cheshunt, 488.
Jurassic rocks in the Lepontine Alps,
2H5.
Karoo Beds in S.E. Africa, 553.
Kemp's Hill (Derbyshire), BIO.
Kenlochewe (Ross-shire), Olenelltts-
fauna from, Bill & pis. xxix.-xxxii.
Kentish Rag, equivalent, in Culford
boring, 4M.r>.
Kenya, Mount, glacial geology of,
.r> 1 ;> ; view of central peak, 5Ki ;
map of 8. W. slopes, 517 ; nature
Sc. age of glaciation, 52U ; causes
of glaciation, 522; climatic con-
ditions during period of maximum
glaciation, 527. .
'Kern' hypothesis of Rosenbusch,
3L3&
Keuper (Upper) at Shrewley, molluscs
in, 170.
Keyserling, A. Ton, obituary, Proc. £3.
Kharga Oasis (Libyan Desert), 532
et itcqq., 537.
King's Sutton (Northants), polyzoa
from Middle Lias of, 111 A. pis. v.-vii.
Kniveton (Derbyshire), tuff, 63L G3£L
Kotzebue Sound (Alaska), mammoth
& other remains, 3, 0_,
Kynaston, H^ on Gosau Beds of
Gosau district (Austrian Salzkatu-
inergut), I2LL
Labrador-porphyrite of Huken, ana-
lysis, 33.
Lady Down (Wilts), section described,
54.
Latran, G. B., & J. R. Leeson, on
Pleistocene deposits in Thames Val-
ley at Twickenham, 453.
Lagena acuticosta, 706; L. apiculata,
705 ; L. globosa, 705 ; L. laeri*.
7< >.r> ; L. Meyeriana, sp. nov., 7tMi &
pi. xxxiv.
Laaomt/9 pusillus, 104 & pi. xi.
Lake-basins, glaciated, of Mount
Kenya, ft 19.
Lake District, petrological papers on,
summarized, Proc. 119.
Landscape Marble, description of
characters, mode of occurrence, &
formation, 393.; theories as to
origin, 899; experiments repro-
ducing, 4115.
743
GEXEBAL INDEX.
[Nov. 1894,
Larus(?\ 192 A pi. x.
Li\a, quartz-enclosures in. Pro". 2 ;
perlitic A spheral itic structures in
vitreous and (If vitrified la^as, 11,
12. A pi. i. ; Carboniferous lavas in
Derbyshire, microscopical structure
or. t*»i l .
Lava-inasses enclosed in Carrock Fell
gtibbro. 315, 331.
Leeson, J. R., A G. B. Laffan, on
Pleistocene Deposits in Thames
Valley at Twickenham, 453.
Leigh Creek (S. Australia) Jurassio
coal -bearing beds. Proc. 6.
Lcpidodendrun in Devonian of Bath-
urst(X.S.\V.), 114.
Lepontine Alps, Mesozoio rocks A
crystalline schist*. 285.
Zscpus timidtts, 193 A pi. xi. ; L.
cunieulus (?), 104.
L.-wis Glacier (Kenya), 515; terminal
moraines of, 522 lig.
Lewisian gneiss, 057.
L'aa (Middle), cheilustomatouspolyzoa
from the, 79 A pis. v.-vii.
Liassic ostrncoda, 150 A pi. ix.
Library, additions to, Pruc. 151.
Library A Museum Committee Report,
Pruc. it.
Libyan Desert of Egypt, stratigraphy
& physiography, 531 A pi. xxi.
(map).
Li in burg (Baden) pyroxene, analysis,
HI.
Lingulina carinata, 708; L. scmi-
ornata, 708 ; L. g. var. cnussa, nov.,
708 A pi. xxxiv.
Littleton Lane (Guildford), Bargate
Stone A Pebble Beds in, 078.
Jyooas, origin of, 484, 480.
Litton (Derbyshire), 011; dolerite
A tuff, 027.
Lizard (Cornwall), papers on the,
summarized, Proc. 131 ; hornblende
schists compared with Cock's Tor
rocks, 355 tt acqy., 304.
Llandeilo, Lower, age of andesitic
ash near Builtb, 572.
Llyn Padarn (Caernarvonshire), suc-
cession W. of, 581, A section, 583;
succession E. of, 580; alleged un-
conformity, 588, A sections, 590,
592 ; geological sketch-map, 594.
London B
in. 513.
geologn
Basin,
table of deep borings
London Clay at Twickenham, 453,
450.
Long Sleddale (Westmoreland), de-
vit rifled obsidian, 12 & pi. i.
Lossen, K. A., obituary, Proc. 54,
Lutmooro, E. B., obituary, Proc.
43.
Lydekker. R , on Argentine fossil
vertebrates, Pntc. 146.
Lyell Fund award to W. Hill. Proc.
38.
Lyell Medal awarded to J. Milne,
Proc 37.
Lyell Medallists, list of, Proc. 24.
Lyons, H. G.,on Stratigraphy A Phy-
siography of Libyan Desert of
Egypt, 531 A pi. xxi.
M 'Mahon, C. A., on Trachytes, meta-
morphosed Tuffs, A other rocks
of Igneous Origin on \V. Flank of
Dartmoor, 338.
Mama. Lake (Norway), analyses of
camptouite A bostonite from, 20,
Magmas, igneous, protrusion A con-
solidation of, 055; differentiation
of common magma originating
various ro<*ks, 20, 31, 35.
Magnesiau Limestone showing rhoin-
bohedra, 3SI A pt. xiv.
Maidenhead (Berks), section to Hasle-
mere, 154.
Maluiani district (Transvaal), gold-
bearing dolomite, 503.
Malmesbury Schists in S.E. Africa,
550.
Malvern Ilills, rocks of the, Proc. 103
tt scqq.
Mammoth-remains, in Yukon district
A Alaska, 1 ; preservation of, 48-\
Manganese ore >n Matto G rosso. 99.
Manganiferous earth, associated wiLn
auriferous beds in S. Africa, 505.
Marble of Altkirche, 287.
Marginulina requivoca, 709; M. corn-
Jressa, 709 ; M. debilis, 70S) ; Af .
onesi, 709 ; M. linearis, 709 : M.
Munieri, 710; M. striatoeostata,
710.
Mashonaland, auriferous A other rocks
from, Proc. 8, 144.
Matto G rosso (Brazil), geology of,
85 ; map of, pi. viii.
Matto Shales, 93.
Meall a' Ghubhaie (Ross-shire) Olenel-
/uj~fauua from, 001 A pis. xxix.-
xxxii.
Meall Dearg (Skye) granophyre, 218.
Meano (Italy), 251.
Meldon ( Devon), tuffs etc of, 347.
Meles taxus(?), 201.
Meaonacis ataphoidcs, 073 flg. 2 A
pi. xxxii.; .V. MickwUsia, 073
fig. 2.
Meaozoic rocks in the Lepontine A Ids,
285.
Mctamorphisra, post-Cambrian, in
H.W. Highlands, Proc. 89.
Digitized by Google
Vol. 50.]
GEXIKAL IXDEX.
•49
* Metnpyrigen-gneisses,' 2r><>.
' MHas miatie quartziu-*,' 380.
Mtc i-tliorite 01 8011th Devon, 351.
Mich- like mineral replacing olivine,
0J0 et sffjq.
Microdot* Mreki, head-shield, 414.
Microtus ( = Arvicola) agrestis, 1V»7 ;
M. amnhibius, 11H> ; M. arvalis,
197 ; M. glareolus, 190 ; ,V. grc-
y«/w, 107 & pi. xi. ; A/, rattiltps,
197 & pi. xi.
Middleton (Derbyshire). Oil.
Milioliua agglutinans, 093.
Miller's Dale Station (Derbyshire)
dolerite & tuff, 631.
Milne, J., Lyell Medal awarded to,
J'ntc. 37.
Mmniaglow (Derbyshire), 610.
Mu>cene in Libyan Desert of Egypt,
535.
Moel Goronwy (Caernarvonshire), sec-
tion across, 51)7.
Moel Tryfaen (Caernarvonshire), suc-
cession at, 5S0.
Mokattam Beds in Libyan Desert,
535.
Molluscs in Upper Keuper at Shrew-
ley, 170 ; in lghthaui fissure, 182,
Molteno Bed* in S.E. Africa, 552.'
Monckton, II. W., on a Variety of
Ammonites (Stcphanoceras) sub-
armatus. Young, from the Upper
Lias of Whitby, Proc. 4 ; on Piei ite
& associated rocks at Burn ton, near
Edinburgh, 39.
Monks Dale ( Derbyshire) tuff, 020.
Moraines, old, on Mount Kenya, 518,
520 ; terminal moraines of Lewis
glacier, 522 fig.
Murehison Fundaward to G. Barrow,
Proc. 36.
MurchUon Medal awarded to W.
T. Aveline, Proc. 35.
Murchison Medallist*, list of, Proc.
Mt<* Ahbotti. sp. nov., 195 & pi. xi. ;
iV. *yhatit'UJt, 194 & pi. xi.
Mint tela rofnista, up. now, 200 6c pi.
xi. ; M. vulgaris, var. mimUa, 201
<fc pi. xi.
Mustione (Italy), 250.
Myalina. restrict ion of name, 438.
Af t/odes lemmus, 196 & pi. xi. ; Af.
torquatus, 193 & pi. xi.
Nics (Norway), bostonite-breccias. 25.
Saiaditcs in Coil-measures of Nova
Scotia, 435 & pi. xx. ; synonymy of,
439 ; X. curbowriu*, 440 & pi. xx.
Nam of Fellow* read out, Proc,
148.
Nerinrea-limeslone in Gosau district,
128, 132.
New Lodge (Berks), artesian boring
at, 152, 49!i.
Newton, E. T., on Vertebrate Fauna
from lghtliam fissure, 188 &. pis.
x.-xii.
Nile Valley, erosion of the, 541.
Nodosaria (Dentalina) brevis, 70,1;
N. Fontaunesi, 707 ; N. liiubnta,
707 ; N. obseurn, 707 ; N. prisma-
tic, 707 ; N. Ru-mori, 700; N. tenui-
cost'i, 707 ; N. xiphioides. 707.
Noudweui (Zululand), auriferous
quartzite from, 38^, 389, 504.
Nouionina scapha, 724.
Nova Scotia, Saiadites in Coal-forma-
tion of, 435 & pi. xx.
Novaculitos, origin of, 377 & pi. xix.
Nubian Sandstone in Libyan Disert,
533. 540.
Number of Fellows, etc , in 1893, Proc.
14.
Oberalp Pass (Switscrland), 287.
Obsidian, perhtic cracks, etc. in, 11,
12.
Oldham, R. D., on Comparison of
Permian Breccias of Midlands with
Upper Carboniferous Glacial De-
posits of India and Australia, 403.
Oknci/oiiuK, subgen. no v., 008 ; 0. ar-
tiuitit*, sp. nov., (109 & pi. xxxii.
Olt'tid/un-tone, additions to fauna in
N.W. Highlands, 001 & pis. xxix.-
xxxii.
OUnellua ataphnides, 415, 410, 42.3;
O. (/i(/tin, sp. nov., 0015, fig. 1 <fc
pi. xxxii. ; O.Gilberti,<M\ & pi. xxvii. ;
O. intermedins, »p. nov.. 000 Sc
pi. xxxii. ; O. L*ipuv»rfhi, 002 &
pis. xxix.. xxx., xxxii. ; O. L. var. * lon-
aatus, nov., 004 & pi. xxix. ; 0 reti-
culata, pp. nov., 005, 073, fig. 2, &
pis. xxx.-xxxi.
Ohviuo-crystals, perlitic cracks in,
374, 375 ; in Derbyshire lavas de-
scribed, 011 ; paeudoinorphs alter,
013,014.
Oliviue-dolerite of Jabel Burka, 533 ;
of Derbyshire. 024.
Olivine-gnbbro-diabase* of Gran dis-
trict, 18 ; analyses of same, 19, 20 ;
contact- metAtuorphisrn by, 21.
Oolito (Inferior) of Shipton Gorge,
polytoa from, 72 & pis. ii.-iv.
Oolite, siiicified, 93.
Ordoviciau rocks, papers on, summa-
rized, Proc. 78.
Ossiferous fissures near Ightham, 171 ;
plants and invertebrata in, 1M ;
\erteb.ate fauna from same, 188
Digitized
750
GENERAL INDEX
[Nov. 1894,
A pis. x.-xii.; table of distribution
of vertebrata, 203.
0*tana (Po Valley), 276.
Odtracoda, Rhretic and Liassic, of
Britain, 156 A pi. ix. ; of Lower
Greensand, 688; from Bargate Beds,
088 A pi. xxxiii.. 725.
Ouachita stone, 377 et $eqq.
Owen, R., portrait presented by
E. Swain, Proc. 14a.
Palnozoio reached at Culford, 490,
4D5 ; in Ware boring, 507.
Pale f Italy), 247.
pjradiso massif (Cottian Alps), 240 ;
gneiss from margin of, pi. xv.
Parkinson, J., ou Leigh Creek Jurassic
Coal-measures, Proc. 6 ; on Physical
A Chemical Geology of Interior of
Australia, Proc. 7.
Patetlina ant iff ua, sp. nor., 718 A
pi. xxxiii. ; P. corrugata, 71H.
Peach, B. N„ on Additions to Fauna
of OfcncUtu-zone in N.W. High-
lands, 6*31 A pis. xxix.-xxxii.
Peak Forest (Iierbyshire) pseudo-
morphs after olivine, 614.
Pellice Valley (Italy). 257.
Pen-ccrig Ilouse (Radnorshire), sec-
tion near, 575.
Pengelly, W., death announced, Proc.
143.
Pennsylvania, cone-in-cone in Devo-
nian (?) of, 7«U A pis. xxxv.-xxxvi.
Pcrgtntia amphorali$, gen. et sp. nov.,
75, 76, A pis. ii., iii. ; P. galcata, sp.
nov., 76 A pi. iii.; P.jugata, sp. nov.,
76 & pis. ii., iv. ; P. jugata, var. 61-
gibbosa, nov., 76 A pis. ii., iv. ;
P. major, sp. nov., 74 A pis. ii., iii. ;
P. minima, sp. nov., 74 A pis. ii.,
iii. ; P. nidulata, sp. nov., 73 A
pis. ii., iii. ; P. portfera, sp. nov., 75
A pis. ii., iv.
Perlitic and sphenilitic structures,
sequence of, 10; perlitic cracks in
quartz, 367 & pi. xviii.
Permian breccias of Midlands, com-
pared with Upper Carboniferous
glacial deposits of India A Aus-
tralia, 463.
Perosa (Italv), 251.
Perrero (Italy). 254.
Phthanitea, radiolarian, in Cottian
series, 268, 269.
Picrite at Bnrnton, 39.
* Pietro vcrdi' series in the Cottians,
233 et tcqq.; * pietre verdi' inclu-
sions in gneiss, 242, 250 ; veins of
aplito in ' p. v.,' 2571; 4 p. v.' in Monte
Chaberton area, 307.
Pitchstoue, porphyritic, of Sandy-
Braes. 368.
Planispirina obscura, sp. nor., 693 A
pi. xxxiv.
Plant, J., obituary, Proc. 51.
Plants in fissures at Ightham, 181.
Plaxtol (Kent), section across val!ey
at, 174: section to near Cutmans
Ash, 175.
Plecotus (Vespertilio) auritus (?),
193.
Pleistocene deposits at Twickenham.
453 ; mammalia, mollusca A plants,
458; (?)at Ightham, 171.
Pliocene in Libyan Desert of Egypt,
535.
Polymorphina amygdaloides, 715 ;
P. communis, 716; P. eompreesa,
716 ; P. concava var. dcntimarginata
nov., 717 A pi. xxxiv. ; P. frondicn-
larioulcs, sp. nov., 716 A pi. xxxiv.;
P. gutta, 715; P. oblonga, 716;
P. regina, 717 ; P. rhahdogonioidez,
sp. nov., 716 A pi. xxxiv. ; P. soro-
ria var. cuspidata, 715.
Polystomella aculeata, 724.
Folyzoa from Inferior Oolite of Ship-
ton Gorge. 72 A pis. ii.-iv. ; from
Middle Lias of Kings Sutton, 79 A
pis. v.-vii.
Portage Flags (Pennsylvania), cone-
in-cone in. 732.
Portland Beds, junction with Purbeck
at Chilmark, 4H ; at Wockley, 49.
Potluck (Derbyshire), 61 1 ; pseudo-
morphs after olivine, 613.
Pre- Devonian in Matto G rosso, 8**.
Prestwich, J., portrait presented by,
Proc. a.
Prilchard, Rev. C, obituary, Proc. 42.
Protocaris Manhi, 413.
Pseudomorphs after olivine, 613, 614.
Pulvinulina elegans, 723; P. Kar-
steni. 723 ; P. punctulata, 723 ; P.
Schreibersii, 723.
Purbeck Beds of t he Vale of Wardour,
44 ; diagram showing vertical suc-
ceiision, 64 ; comparison with those
of Dorset, 65 ; list of fossils. 68.
Purtiall (Deccan). siliceous pebble
from, 381 A pi. xix.
Pvroxene, rhombic, in Derbyshire
lavas, 620.
Pyroxenite of Brandberget, analysis,
31.
Quart i -enclosures in lava of Strom-
boli, Proc. 2 ; quartz in Carrock
Fell gabbro, 318 ; quartz-vein in
tuffs near Meldon. 349; perlitio
cracks in quartz, 367 A pi. xviii. ;
Digitized by Google
Vol. 50.]
GENERAL INDEX.
751
quartz-reefs in Silurian of Bathurst,
113.
Quartzites, origin of Mine, 377 &
pi. xix. ; classification of, 380 ;
auriferous, from Nondweni, 3 s*,
'ML
Quartzitic induration of surface-rocks,
Proc. 7.
Quaternary in Matto G rosso, OS.
Radiolarian phthanitet in Cottian
Alps. 268, 2tfiL
Rainfall in Equatorial East Africa,
529; in Pleistocene Egypt, 512.
' Rain-spot' breccia, near JJyn
Pndarn, ML
Raisin, Miss C. A., & T. O. Bonney,
on Relations ot Older Fragmental
Rocks in N.W. Caeriuirvonsbire,
f>78.
Ratnulina globtdifera, 717.
liana temporaria, 18i) &. pi. x.
Hauyifer ( = Ct rvus) taramttu, 1119 &
pi. xi.
Rauchwacke in Lepontine Alps, 288
et ficqq.
Rarensdale Cottage (Derbyshire), tuff,
Realp (Switzerland), section near,'
2U3.
Red Beds in S. Africa, 551.
Report of Council for 181)3, Proc. 10;
of Library & Museum Committee,
Proc. 1a ; financial, Proc. iiL
Rka-tic ostracoda of Brituiu, ibJl &
pi. ix.
Rhinoceros antiquitatit, 1H8 & pi. xi.
Rhyolites of Was Tor, 3li3_ ; of
Tardree, 363 ; of Builtb district,
573.
Richmond (8urrey) boring. Neocomian
limestone from, 68;). 6fS6.
Rid«e (Wilts) section described,
b±
Riebeckite in granophyre of Skye, 21iL
River-terraces, age of, 44'J.
Rizama Sandstone, U3.
, Romford (Essex) map of district,
444 ; section near, 445.
Ross, W. J. C, on the Geology of
Bathurst (N.8.W.), 105,
Rotalia Bcccarii, 724.
Rtisshachthal (Sulzkammergut), Gosau
Beds in, 128,
Rut ley, F., on the Sequence of Perlitic
& Snherulitic Structures, ill & pi. L;
on the Origin uncertain Novaculites
and Quartzitcs, 377 &. pi. xix.
Saiga antelope at Twickenham, 459,
460,4ii2,
Sand (Pleistocene) at Twickenham,
analysis, 457.
Sandy Braes (Antrim), perlitic pitch-
stone from, 367 & pi. xviii.
Sandy Dale (Derbyshire), 62L
Santa Cruz, Barrados Bugies (Brazil),
section near, ill,
Sao hirsuta, 417.
Sawyer. A. R., on rock-specimens from
South Africa, Proc. 144.
Saxicola (Eaanthe (?), iiU k pi. x.
Schists, conversion of compact green-
stones into, 27JL
Scotland, penological papers on,
summarized, Proc. 107.
Scotophilus pipistrell.is (?), 103.
Selitua Oasis (Libyan Desert), wells
in, 53U.
Serpentine, altered, in Cottian Alps,
244, 249 ; pre-Triasaic in Monte
Chaberton area, 3U7 ; aluminoun,
of Was Tor, 'ML
Shap granite, Pro: IU} rt geqj.
Shingle Hill (Kent), section to Cot-
man's Ash, 174 ; section to Hurst
Wood, 174.
Shipton Gorge (Dorset), polyzoa from
Inferior Oolite of, 12 & pis. ii.-iv.
Shode Valley, ossiferous fissures in,
1 7 1 ; sections, 174, 1 75 ; history of,
172.
Shrewley (Warwickshire), discovery
of molluscs in Upper Kmper, 170.
Shrubsole, G. W., obituary, Proc.
47-
Silicified wood in Libyan Desert, 534,
536 ; origin of, 545. 547 • in Red
Beds of 8.E. Africa, 552; silicitied
oolite, *J±
Silurian rocks, papers on, summarized,
Proc. 2% ; Silurian of Bathurst
(N.S.W.), LLL
Skve, relations of gnbbro Sl granophyre
in, 2U> et seqq. ; banded structure
of Tertiary gabbros in, 645 &
pis. xxvi.-xxviii.
Sligachan, Glen (Skye), 218 et ter/q.
Snow, disappearance by melting &
evaporation, 481.
Snow-drift, deposits from, 472: form-
ation of, 475 ; hardening of, 47(J ;
fine texture of deposits. 482 ; ab-
sence of stratification, 482.
Solvsberget (Norway), olivine-gabbro-
diabase, analyses, 19j 211 ; geol.
structure of the hill, 21 ; pyro-
xenites, etc. of, 33^ HL
Soret's principlo discussed, 326.
Sorrx pyymteus, H12 <& pi. xi. ; S. vul-
garis, 1112 & pi. xi.
Sourton Tors (Devon), tuffs, feleites,
etc. of, 338 ; map, 33JL
752 GENEB
South Down (Devon), mica-diorite of,
350; grnnitc-outcrop, 350.
South Joggin* (Nova Scotia), Coal-
measure shells from, 437 & pi. xx.
Special Geneml Meeting, Proc. I 50.
Specific gravities as a test of relative
basicity of gabbro, 321.
Spencer, J., obituary, Proc. 51.
Spermophilus, 194.
Spheroidal structure in rocks at
Grange Mill, 634.
Spherulites in Skye granophyre, 220,
221.
Spberulitic and perlitic structures,
sequence of, 10.
Spiroplecta annectens, 700 ; 8. bi for-
mic, 7W.
Sponge spicules, in Bargnte Stcn?,
(580, <>K3.
St. Lucia Bay (S.E. Africa) section to
Mont-aux-Sources, Draken&bcrg,
pi. xxii ; anthracite at, 553.
St. Martha's Chapel (Chilwortb),
Bargate Beds near, (581.
Staden Low (Derbyshire). 020.
Strahan, A., Wollaston Fuud award to,
Proc. 34.
Striated stones in Permian breccias,
400 ; rocks on Mount Kenya, 520.
Stromboli, quartz-enclosures in lava
of, Proc. %.
Stur, D.f obituary, Proo. 55.
Surface metamorphistn in 8. Aus-
tralia, Proc. 7.
Stis scrofa, 200.
Susa (Italy), 245.
Swain, K., presentation of R. Owen's
portrait, Prvc. 142.
Table Mountain Sandstone in S.E.
Africa, 555.
Taboleiros (Matto Grosso), sandstone
of the, 98.
Taddington Field (Derbyshire), 610.
Talpa europa?a, 192.
Tan-y-graig (Radnorshire), section
south of, 572.
Tapirapuam Hills (Brazil), section to
Cuyaba, 89.
Tardrco (Antrim), rhyolite of, 367,
aw.
Teall, J. .T. H.. & Sir A. Otikie, on
Banded Structure of Tertiary Gab-
bros in Skye, 645 & pis. xxvi.-xxviii.
TefTont Evias (Wilts), sections near,
described, 53, 55.
Terrace, the, E. of Drakentberg (S.
Africa), 549.
Terraces in Thames Valley, 448 ?t seqq.
Tertiary volcanic series of Inner He-
brides, relations of basic & acid
L IXDEX. [Xov. 1894,
rocks, 212 & pis. xiii.-xiv. ; Tertiary
gabbros in Skye, banded structure
of, 045 &pls. xxvi.-xxviit.
Textularia agglutinans, Cit>9; T. gra-
men, 698 ; T.minuta. 098 ; T. pr-.e-
longa, 698; T. sagittula, 698; T.
trochus. 699 ; T. turris, 699.
Thames Valley Beds, relation to
Boulder Clay, 448 rt veqq. ; Pleist*>-
cene deposits in Thames Valley at
Twickenham, 453.
Thompson, B., on Landscape Marble,
393.
Thrust-planes in the N.W. Highlands,
Proc. 90.
Tisaington (Derbyshire), 610.
Titaniferous iron-oxide* concentrated
in highly basic rocks, 318, 323. 324.
Toadstune, derivation of term, 604.
Torridon Sandstone, Proc. 94.
Trachytes of Sourton Tors, ,'i45.
* Trap-atnygdaloids' in S. Africa, 551.
7ruirtnnii lleckii, with antenna, 425,
426.
Trias (?) in Matto Grosso, 97.
Trilobites, systematic position of the,
411 ; formation of head-shield, 413.
417 ; bending-round of 1st cephalic
segment, 416; eyes in, 420; dorsal
organ in, 422 ; anus in, 424 ; limbs
of, 424 ; classification, 430.
Tritaxia tricarinata, 699.
Trochammina squamata, var. limbata
nov., 697 & pi. xxxiv.
Tropidonotus natrix, 190.
TntncatuUna falcata, 721 & pi. xxxir ;
T. Haidingerii, 722; T. lohutula,
721 ; T. variabilis, 721 ; T. Wuel-
lerstorfi, 722.
Tufa deposits in S. Africa, 564.
Tuffs, volcanic, of Sourton Tors. 340 ;
of Meldon, 347 ; of West Okement
River, 349, 351 ; ' corduroy ' struc-
ture in, 351 ; Carboniferous, of
Derbyshire, microscopical struc-
ture, (503 Apis, xxiv.-xxv.
Turn ford boring, i08.
Twickenham (Middlesex), Pleistocene
deposits at, 453 ; sections, 455, 456.
Tyndall, J., obituary, Proc. 41.
Unconformity, alleged, E. of Llyn
Padarn, 588 ; section. 592.
Underground-ice formation, origin of,
485.
Upminster (Essex), sections seen on
railway to Romford, 443.
Vi sits arcfos (?), 201 & pi. xii.
Urucum (Brazil), crystalline rocks at,
88 ; iron & manganese ores at, 99.
Digitized by Google
Vol. 50.]
GTXKRAL INDEX.
753
Vaginulina arguta, 710 ; V. legumen,
710 ; I', neocomiatia, sp. nov., 711
& pi. xxxiv. ; V. sparsicostnta, 710.
Val Bed ret to, rocks in the, 2112.
Val Canaria, rock* in the, 297.
Valley-glaciers, 5_liL
Valvulina conica, 201 ; V. fuses. 701.
Variolites, papers on, summarized,
Proc. 124.
Vectian Sand in Vale of Wnrdour, Qi
Verneuilina triquetra,
Vertebrates, fossil, from Argentina,
Proc. i^fi; vertebrate fauna from
Ightham fissure, 188 & pis. x.-xii.
Vefi/.irtifio Hattertri, 19.2 & pi. xi.
Vilanova y Piera, J., obituury, Proc*
r54-
Viper a (Petias) berus, 190 <fc pi. x.
Virgulina subdepressa, 704 ; V. sub-
equamosa, 703.
Volcanic series, Tertiary, in Inner
Hebrides, relations of basic and
acid rocks, 212 & pis. xiii.-xiv.
Vonzo (Cottian Alps), 2iL
Vredefort (Orange Free State), sec-
tion to Hartebeest-Fonlein, pi. xxiii.
Wadi Haifa (Egypt), 533. ef *cqq.
Wadi Natrun (Egypt), Miocene of,
530.
Wtddensian Gneisses, 232-239 ; sketch-
map of distribution, 2.S8.
Walford, E. A., on Bryozoa from In-
ferior Oolite of Shipton Gorge
(Dorset), 22 «fc pis. ii.-iv. ; on Chei-
lostomatous Bryozoa from the
Middle Lias, 19. Hi pis. r.-vii.
Wurdour, Vale of (Wilts), Purbeck
Beds, 4A. ; geological map of dis-
trict, 47_.
Ware (Herts), boring near, 501 ; de-
scription of samples from, 5l>3 ;
classification of beds, 500.
Was Tor (Devon), rhyolite, etc, of,
3(12.
* Wash-outs' in coal-seams, Proc. 64.
Water, from Winkfield boring, che-
mical analysis, 50 I .
Water-supply in Libyan Desert, in
relation to anticlinal folds, [i2H;
in Lower Greensand south of
Windsor, 153, 155.
Watts, W. WT., occurrence of perlitic
cracks in quartz. 30? & pi. xviii.
Wen lock Beds in Ware boring, 507.
West Okement River (Devon), tuffs,
etc., 347.
Whitaker, W., & A. J. Jukes-Browne,
on Deep Borings at Culford &
Winkfield, with Notes on those at
Ware & Cheshunt, 488.
Whitby (Yorks), Ammonites subar-
matus from, Proc. 4.
Windsor Forest (Berks), artesian
boring near, l.*>2. 490.
Winkfield (Berks) deep boring at,
4 '.Hi ; water from the, 499 ; chemical
analysis of same, 501 .
Wockley (Wilts), section described,
Wollaston Fund award to A. Strahan,
Proc. 24.
Wollaston Medal awarded to K. A.
von Zittel, Proc. 12.
Wollnston Medallists, list of, Proc. 1 1 ;
recipients of awards from fund,
Proc. za.
* Wonder Holes ' (water-holes) in
Malmuni dolomite, 5<>3.
Wood, silicified, in Libyan Desert,
534. 53i i ; origin of, 545 ; in Red
Beds of S.K. Africa, aii2.
Woodburr Hill, Permian breccias of,
41><>. 407.
Woods, II., on Igneous Rocks of
neighbourhood of Built h, 500.
Yellowstone Park (U.S.A.), perlitic &
spherulitic structures in rocks from,
11 & pi. L
Yukon district (Canada), mammoth-
remains in, L
Zittel, K. A. von, Wollaston Medal
awarded to, Proc. ]z.
END OF VOL. I..
Printed by Taylob asd Fkaxos, Red Lion Court, Fleet Street
PROCEEDINGS
or inE
GEOLOGICAL SOCIETY OF LONDON.
SESSION 1893-94.
November 8th, 1893.
W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.
Louis Honry Cooke, Esq., Assoc.R.S.M., Assistant to the Pro-
fessor of Mining at the Royal College of Science, Loddington, Ket-
tering, and Richard A. S. Redmayne, Esq., Harewood, Gateshead-
on-Tyne, were elected Fellows ; and Monsieur Ed. Rigaux, Boulognc-
sur-Mer, was elected a Foreign Correspondent of the Society.
The List of Donations to the Library was read.
Prof. J. W. J odd made a few remarks in explanation of the
specimen exhibited by him.
The following communications were read : —
1. 'The Geology of Bathurst, Now South Wales/ By W. J.
Clunies Ross, Esq., B.Sc, F.G.S.
2. 'The Geology of Matto Grosso (particularly of the Region
drained by the Upper Paraguay).' By J. W. Evans, D.Sc, LL.B.,
F.G.S.
3. * Notes on the Occurrence of Mammoth-remains in the Yukon
District of Canada and in Alaska.' By George M. Dawson, C.M.G.,
LL.D., F.R.S., F.G.S.
The following specimens were exhibited : —
Sections and rock-specimens from the District of Bathurst, New
South Wales, exhibited by J. T. Day, Esq., F.G.S. , in illustration of
Mr. W. J. Clunies Ross's paper.
Sections and rock-specimens from Matto Grosso, exhibited by
J. W. Evans, D.Sc, LL.B., F.G.S., in illustration of his paper.
Examples of Composite ' Contemporaneous ' Veins (Aplite) tra-
versing the Granite of Beinn Cruachan, Argyllshire, exhibited by
Prof. J. W. Judd, F.R.S., V.P.G.S.
vol. L. a
Digitized by Google
2 P BOOHED INOB OP THE GEOLOGICAL 80C1ETT. [Feb. 1894,
Specimens of Cassiterite, Antimonite, Zaratite, and Phacolite,
from Victoria, Australia, exhibited by F. Danvers Power, Esq.,
F.G.8.
Specimen from Goathnrst Common, near Ide Hill, Kent, exhibited
by the Rev. R. Ashington Bullen, B.A., F.G.S.
November 22nd, 1893.
W. H. Hudlbbton, Esq., M.A., F.R.S., President, in the Chair.
George Henry Hill, Esq., M.Inst.C.E., 3 Victoria Street, 8.W.,
and Albert Chambers, Albert Square, Manchester, was elected a
Fellow of the Sooiety.
The List of Donations to the Library was read.
The Secretary announced that Prof. J. Prestwich, D.C.L., F.R.S.,
had presented a large framed photograph of himself to the Society.
The following communications were read : —
1. «The Basic Eruptive Rocks of Gran/ By W. C. Brbgger,
Ord. Prof, of Min. and Geol. in the University of Chriatiania,
For. Memb. Geol. Soc.
2. 'On the Sequence of Perlitic and Spherulitic Structures (a
Rejoinder to Criticism)., By Frank Rutley, Esq., F.G.S.
3. 4 Enclosures of Quartz in Lava of Stromboli, etc., and the
Changes in Composition produced by them.'1 By Prof. H. J.
Johnston-Lavis, M.D., F.G.S.
[Abstract]
The Author describes the existence of enclosures of quartz in a
lava-stream at the Punta Petrazza on the east side of Stromboli,
and also in the rock of the neck of Strombolicchio. He describes the
effects of the rocks upon the enclosures, concluding that the quartz
has undergono fluxion but not fusion, and has supplied silica to the
containing lavas, thus causing an increase in the amount of pyroxene
and a diminution in the amount of magnetite in the portions of
those lavas that surround the inclusions and raising the percentage
of silica. He suggests that such a process at greater depths and
higher temperature may, under certain conditions, convert a basic
rock into a more acid one, so that possibly the andesite of Strombo-
licchio may have been of basaltic character at an earlier period of
its progress towards the surface. He offers the suggestion that
other rocks or minerals once associated with the quartz have been
assimilated by the magma.
1 This paper has boen withdrawn by permission of the Council
Digitized by Google
Vol. 50.]
PROCEEDINGS OP THE GEOLOOICAL SOCIETY.
3
Discussion.
The President and Prof. Judd spoke.
The following specimens were exhibited : —
Rock-specimens exhibited by Prof. W. C. Brogger, For.Memb.G.B.,
in illustration of his paper.
Specimens and microscope-sections, exhibited by Frank Rutley,
Esq., F.G.S., in illustration of his paper.
Specimens and microscope-sections, exhibited by Prof. H. J.
Johnston-Lavis, M.D., F.G.8., in illustration of his paper.
A new mineral found at Greenbushes, Bunbury, Western Aus-
tralia, associated with alluvial Cassiterite, exhibited (with analysis)
by F. Danvers Power, Esq., F.G.S.
December 6th, 1893.
W. H. Htjdleston, Esq., M.A., F.R.S., President, in the Chair.
Henry Dyke Acland, Esq., Great Malvern ; John Forbes Bryant,
Esq., B.A., Clare College, Cambridge ; David Draper, Esq., Lennox-
ton, Newcastle, Natal; Gavin H. Jack, Esq., 10 Pennel Square,
Pontypridd, South Wales ; Septimus Heslop, Esq., Asansol, E.I.R.,
India; James Henry Howarth, Esq., The Crescent, Newton Park,
Leeds; William Humble, Esq., Wickham, Newcastle, New South
Wales ; Arthur Walton Rowe, Esq., M.S., M.B., M.R.C.S., 1 Cecil
Street, Margate ; Joseph Scott, Esq., Newcastle Street, Stockton,
New South Wales ; William Simpson, Esq., Savile Mount, Halifax ;
Victor Streich, Esq., care of Messrs. Harrold Brothers, Adelaide',
South Australia; John James Turnbull, Esq., Giridih, E.I.R.,
Bengal, India ; and Albert Wilmore, Esq., Trawden, Colne, Lanca-
shire, were elected Fellows of the Society.
The List of Donations to the Library was read.
In explanation of a specimen exhibited by F. B. Du Pre, Esq.,
M.A., F.G.S., Mr. Horace W. Moncxton remarked that the
specimen came from a dyke in the Brockwell Seam at the Crox-
dale Collier}', about 2 miles south of Durham, depth 80 fathoms.
This is probably the dyke described by Mr. Teall as 2 miles north
of the Hett Dyke (' Brit. Petrography/ p. 202). The greater part
of the rock is composed of lath-shaped plagioclase-felspar ; the
remainder appears to be augite, or change-products after augite, and
iron oxide.
The following communications were read : —
1. « The Purbeck Beds of the Vale of Wardour.' By the Rev. W.
R. Andrews, M.A., F.G.S., and A. J. Jukes- Browne, Esq., B.A.I
F.G.S. ^
2. 4 On a Picrite and other associated Rocks at Barnton, near
Edinburgh.' By Horace W. Monckton, Esq., F.L.S., F.G.S.
Digitized by Google
4
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 1894,
3. 4 On a Variety of Ammonites (Stephanoceras) subarmatus,
Young, from the Upper Lias of Whitby.' By Horace W. Monckton,
Esq., F.L.S., F.G.8.
[Abstract]
The Author exhibited an ammonite found by himself in 1874
near Sandsend, 3 miles north-west of Whitby. He thinks it was
not actually in situ, but lying with a number of nodules on the
floor of an old alum-pit, although he has no doubt that it is from
the Alum Shale of the Upper Lias. A peculiar arrangement of the
costs® as they cross the siphonal area distinguishes the specimen
from other Whitby ammonites known to the Author. It bears a
strong resemblance to a shell figured as A. subarmatus by D'Orbigny,
4 Terr. Jurass.,' pi. lxxvii., but is unlike the figures of that species
given by other authors.
Discussion.
Prof. J. F. Blaxe said that the ammonite in question seemed
nothing unusual. It would be included in the varieties or mutations
of subarmatus, the genus of which was not Stephanocerxu.
Mr. George C. Crick also spoke.
The Author, in reply, pointed out that he only claimed his fossil
to be a variety, not a new species ; and if a variety, it must be a
variety of some species. He thought it was less unlike A. sub-
armatus than other Liassic species. In any case, it was, he thought,
the A. subarmatus of D'Orbigny, and in assigning that species to
Sttphanoa>ras he had simply followed Dr. Wright.
In addition to the specimen described on the preceding page, the
following were exhibited : —
Rock-specimens from Barnton, near Edinburgh ; and specimen
of Ammonites subarmatus, var., from the Lias of Whitby, exhibited
by Horace W. Monckton, Esq., F.L.S., F.G.8., in illustration of his
papers.
Specimens of Scottish Granite, exhibited by Horace W. Monckton,
Esq., F.L.S., F.G.S.
December 20th, 1893.
W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.
Arthur Hassam, Esq., Waverley House, Fenton, Stoke-on-Trent;
Robert Ludwig Mond, Esq., M.A., F.R.S.E., F.C.S., The Poplars,
20 Avenue Road, Regent's Park, N.W. ; and Llewellyn Treacher,
Esq., Somercroft, Twyford, Berkshire, were elected Fellows ; Dr. E.
Mojsisovics von Mojsvar, Vienna, and Dr. A. G. Nathorst, Stock-
holm, Foreign Members ; and Dr. 8. L. Tornquist, Lund, a Foreign
Correspondent of the Society.
The List of Donations to the Library was read.
The following communications were read : —
Digitized by Google
Vol. 50.J
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
5
1. 4 On the Stratigraphical, Lithological, and Paheontological
Features of the Gosau Beds of the Gosau District, in the Austrian
Salzkammergut.' By Herbert Kynaston, Esq., B.A. (Communicated
by J. E. Marr, Esq., M.A., F.R.S., Sec.G.S.)
2. * Artesian Boring at New Lodge, near Windsor Forest, Berks.'
By Prof. Edward Hull, M.A., LL.D., F.R.S., F.G.S.
3. * Boring on the Booyson Estate, WitwatersrandV By D.
Telford Edwards, Esq. (Communicated by the President.)
[Abstract.]
The borehole is situated about 2 miles from Johannesburg, and
about 5000 feet due south of the Wommer Gold Mining Company's
main hauling shaft. It was carried to a depth of 1020 feet. The
measures passed through were sandstones and quarUites, with banks
of conglomerates, the so-called * reefs.' A group of these conglo-
merates, known as the Bird Beef series, was cut between the dept hs
of 470 and 970 feet ; it contained eighteen beds of conglomerate,
two of which, at the respective depths of 536 and 636 feet, were
22 and 26 feet in thickness, and yielded no trace of gold. The
remainder varied from 2 feet to 5 inches in thickness ; in eight of
them traces of gold were detected, and all were mineralized with
iron pyrites. The dip varied from 32° to 35° down to a depth 0/
835 feet ; here it seemed to decrease for a while to 20°, but lower
down it increased to 32° and 33°.
[The lower part of the boring passed through country rock
(quartzite).— Feb. 5th, 1894.]
The following specimens were exhibited : —
Specimens of rocks from a deep boring and other workings in the
neighbourhood of Johannesburg, South African Republic, collected
by H. C. Simpson, Esq. Exhibited by W. J. Lewis Abbott, Esq.,
F.G.S.
January 10th, 1894.
W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.
Walter Cleeve Edwards, Esq., Assoc.M.Inst.C.E., Midland Rail-
way, Greymouth, New Zealand; Thomas Walker Fowler, Esq.,
Assoc.M.Inst.C.E., Modern Chambers, 317 Collius Street, Mel-
bourne, Victoria : Edmund William Janson, Esq., B.A., Trelo-
warren Street, Camborne ; and Thomas Escolme Storey, Esq.,
Weston Coyney Hall, Longton, Staffordshire, were elected Felluws
of the Society.
tol. l. b
6
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1894,
The following Fellows, nominated by the Council, were elected
Auditors of the Society's Accounts for the preceding year: —
H. W. Moxckton, Esq., F.L.S., and J. Hopkinson, Esq., F.L.S.
The List of Donations to the Library was read.
The following communications were read : —
1. 'On the Rhfletic and some Liassic Ostracoda of Britain/ By
Prof. T. Rupert Jones, F.R.S., F.G.S.
2. ' Leigh Creek Jurassic Coal-Measures of South Australia : their
Origin, Composition, Physical and Chemical Characters ; and Recent
Subaerial Metamorphism of Local Superficial Drift/ By James
Parkinson, Esq., F.G.S., F.C.S.
[Abstract.]
This paper contains an account of the lignitic coal of Leigh
Creek and associated rocks. Analyses are given, as illustrating
comparisons between the Leigh Creek coal and Jurassic and other
coal-bearing rocks found elsewhere. The Author discusses the
origin of the Leigh Creek deposits, and describes certain peculiarities
noticeable in the superficial materials, which he discusses in another
paper.
Discussion.
The President remarked that the meeting was taken at a disad-
vantage, since it was probable that no one knew the district, and,
moreover, there was no one present to demonstrate the miscellaneous
collection on the table which was supposed to illustrate the paper.
It would seem that the Author takes it for granted that the Leigh
Creek beds are of Jurassic age, and no one present could deny it,
although he (the President) was not aware that the paper contained
any paheontological evidence to that effect. The Author appears to
be attacking somebody — probably a Government surveyor. On the
whole, one would say that he was more of a chemist than a geolo-
gist. In concluding his remarks, the President called attention to
an analysis of South Australian crocidolite, as compared with speci-
mens from Africa.
Mr. A. R. Bbowne regretted that the Author had not given any
idea of the commercial value of the deposit, and pointed out that the
question was one of great importance in South Australia, as on it
depended, amongst other things, to a great extent the working of
many large mineral deposits in the vicinity. He had visited the
field and made analyses of the coal, which he found to be very
similar to that of the Tertiary deposits near Teplitz in Bohemia.
Digitized by Google
Vol. 50.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY
7
3. ' Physical and Chemical Geology of the Interior of Australia :
Recent Subaerial Metamorphism of Eolian Sand at ordinary
atmospheric temperature into Quartz, Quartzite, and other stones?
By James Parkinson, Esq., F.G.S., F.C.S.
[Abstract.]
South of the Flinders Range fragments of stone of all sizes a-e
found on the ground, the origin of which the Author discusses. Ho
maintains that they were formed by subaerial metamorphism of
Eolian deposits.
Discussion.
The President said that this was rather a startling communication,
though he was by no means prepared to say there was nothing in
it. He alluded to the well-known effects of hot climates in this
respect.
Mr. R. D. Oldham said that a quartzitic induration at the surface,
similar to that described by the Author, was noticeable in the more
arid parts of India. In the desort of Western Rajputana he had
found the soft Upper Jurassic sandstones locally indurated into hard
glassy quartzites, and the change appeared to be superficial. In
the diamond mines of Southern India the superficial nature of the
alteration was evident, for the miners, after penetrating the quartzitic
rock near the surface, found the deeper-seated portions to be soft
and easily worked. The cement was in every case siliceous.
Prof. T. Rupert Jones remarked, with regard to the rough,
cylindrical holes traversing some of the quartzitic rock in different
directions, that tboy reminded hira of similar cavities which he had
seen in septaria of the London Clay ; and were probably due to the
imbedment of tough, wrinkled stems of long seaweeds or other
rope-like plants.
Dr. Henry Woodward drew attention to the collection sent homo
by Mr. Parkinson, and suggested that the cavities in sandstone,
referred to by the Author, may have been formed by stems of plants
which havo since decayed, or they may be annelid tubes. He
pointed out certain casts of bodies resembling the so-called ' fucoid '
(Ifarlania Halli) from Niagara Falls, also met with on the Gold
Coast, W. Africa, and in the Mokattam Quarries, near Cairo.
These are probably all due to annelids.
Mr. Marr, Dr. G. J. Hinde, and Mr. E. T. NEwroN also spoke.
The following specimens were exhibited : —
Entomostraca from the Rhajtic and Lower Lias of Warwickshire,
Gloucestershire, etc., exhibited by the Rev. P. 13. Brodie, M.A.,
F.G.S., the Rev. H. H. Winwood, M.A., F.G.S., Edw. Wilson, Esq.,
F.G.S., W. Cunnington, Esq., F.G.S., and Prof. T. Rupert Jones,
F.R.S., F.G.S., in illustration of the paper read by the last-named.
Specimens exhibited by James Parkinson, Esq., F.G.S., F.C.S.,
in illustration of his papers.
12
Digitized by Google
8 PROCEEDINGS OF THE GEOLOGICAL SOCIETT. [^aJ * &94t
January 24th, 1894.
W. H. Hudlbstos, Esq,, MA., F.KS„ President, in the Chair.
Herbert Kynaston, Esq., B.A., The College, Durham ; James
Francis Markes, Esq., 31 Queen Street, Melbourne, Victoria;
Henry Preston, Esq., Hawthornden Villa, Grantham ; and George
Thurland Prior, Esq., MJL, 50 Munster Road, Fulham, 8.W., were
elected Fellows of the Society.
The List of Donations to the Library was read.
The following communications were read : —
1. 'The Ossiferous Fissures in the Valley of the Shode, near
Ightham, Kent.' By W. J. Lewis Abbott, Esq., F.G.S.
2. 4 The Vertebrate Fauna collected by Mr. Lewis Abbott from
the Fissure near Ightham, Kent.' By E. T. Newton, Esq., FJtJS.,
F.G.S.
The following specimens were exhibited : —
Specimens of the Vertebrate Fauna, etc., from the Fissure near
Ightham, Kent, exhibited by Messrs. W. J. Lewis Abbott, F.G.S.,
and E. T. Newton, F.B.S., F.G.S., in illustration of their papers.
February 7th, 1894.
W. H. Hudleston, Esq., M.A., F.B.S., President, in the Chair.
Alfred Alcock, M.B., Surgeon-Captain I.M.S., Superintendent of
the Indian Museum, Calcutta, and Professor of Zoology in the Uni-
versity of Calcutta, Calcutta, India ; William Wickham King, Esq.,
Pedmore House, near Stourbridge ; and Samuel Sydney Piatt, Esq.,
Assoc.M.Inst.CE., 14 King Street South, liochdale, were elected
Fellows of the Society.
The List of Donations to the Library was read.
Mr. C.J. Alfohd, F.G.S., in explanation of specimens of auriferous
rocks from Mashonaland exhibited by him, stated that several of
them were vein-quartz occurring as segregations in the slates,
generally forming veins between the cleavage-planes. Another
specimen was a mass of chromate of lead, with pyromorphite and
other lead minerals, occurring in masses in decomposed and dislo-
cated talcose slate in the Penhalonga Mine near Umtali, and probably
resulting from tho alteration of masses of galena by weathering,
Digitized by Google
Vol 50.] PR00EBDIKO8 OF THE GEOLOGICAL SOCIETY. 9
as a broken vein of galena was found in close proximity. This
crocoisite was supposed to be a somewhat rare mineral, but he
had found it and also the native red oxide, minium, in several places
in South Africa. The most interesting specimen was, however, a
mass of diorite showing visible gold throughout the rock, an assay
of which gave upwards of 130 ounces of gold per ton. From
information obtained from the prospector who made the discovery,
he gathered that the deposit was a dyke of diorite running for a
considerable distance, about 8 feet in width, flanked on one side
by granite and on the other by slates. There were extensivo
anciont workings extending to a depth of about 60 feet, and the
prospecting shafts had not gone much below that depth, so not
much information was obtainable at present. The diorite showed
a development of epidote, but little or no quartz; and the gold
appeared to enter in an extraordinary manner into all of the com-
posing minerals. Mr. Alford hoped, after his next visit to Mashona-
land, to be in a position to lay before the Society more definite
information regarding these interesting rocks.
The following communications were read : —
1. »On some cases of the Conversion of Compact Greenstones
into Schists.' By Prof. T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S.
2. 'The Waldensian Gneisses and their Place in the Cottian
Sequence.' By J. Walter Gregory, D.Sc, F.G.S.
In addition to the specimens described by Mr. C. J. Alford, the
following were exhibited: —
Hock-specimens and microscope-sections, exhibited by Prof. T. G.
Bonney, D.Sc., LLJ)., F.H.S., F.G.S., in illustration of hk paper.
Rock-specimens and microscope-sections, exhibited by Dr. J. W.
Gregory, F.G.S., in illustration of his paper.
A series of Flint Implements from Broom Ballast-Hole, Hawk-
church, Devon, exhibited by the Rev. R. Ashington Bullen, B.A.,
F.G.S.
Digitized by Google
ANNUAL GENERAL MEETING,
February 16th, 1894.
W. H. Hudleston, Esq., M.A., F.R.S., President, in the Chair.
Report op the Couucil for 1893.
Iy congratulating the Fellows on the prosperous condition of the
Society's finances, the Council desire at the same time to draw
attention to the fact that the decrease in the number of Fellows,
which began to make itself apparent in 1892, has continued during
1893.
The number of Fellows elected into the Society in that year was
42, of whom 33 paid their fees before the end of 1893, making,
with 6 previously elected Fellows who paid their fees in 1893, a
total accession in the course of the twelvemonth of 39 Fellows.
During the same period, however, there was a total loss of
85 Fellows — 42 by death, 16 by resignation, 16 removed from the
list for non-payment of their Annual Contributions, and 11 (9 of
whom were non-Contributors and 2 were Compounders) removed
from the list after having remained thereon for many years without
any known address.
The actual decrease in the number of Fellows is, therefore, 46.
Of the 42 Fellows deceased, 10 were Compounders, 24 were Con-
tributing Fellows, and 8 were non-Contributing Fellows.
On the other hand, in the twelvemonth under review, 6 Fellows
compounded for their Annual Contributions.
From the above figures it will be gathered that the actual
decrease in the number of Contributing Fellows is 23, making a
total of 873 Contributing Fellows, as compared with 896 at the
end of the previous year, and 904 at the end of 1891. In calcu-
lating this decrease, tho 11 removed from the list for want of
addresses are, of course, not included.
The total number of Fellows, Foreign Members, and Foreign
Correspondents, which at the end of 1891 was 1418, and at the
end of 1892 was 1400, stood at 1353 on December 31st, 1893.
Digitized by GoogDe
Vol. 50.]
ANNUAL KEFORT.
II
At the end of 1892 there was 1 vacancy in the list of Foreign
Members. During the year which has just elapsed the Society has
lost by death 3 Foreign Members and 3 Foreign Correspondents.
These vacancies were partly filled by the election of 4 Foreign
Members and 5 Foreign Correspondents, but at the end of 1893
there were still 2 vacancies in the list of Foreign Correspondents.
The Society's Income and Expenditure in the year under review
may be summarized as follows : —
The total Receipts amounted to £2750 18*. I0d., being
£205 4*. 6d. more than the estimated Income for 1893. On the
other hand, the total Expenditure during that year (leaving out of
account the sum of £502 15*. 3d. expended in the purchase of
£300 London, Brighton, and South Coast Railway 5°/0 Consolidated
Preference Stock) amounted to £2204 17*. (><?., being less by
.£258 4*. than the estimated Expenditure for 1893. The actual
excess of Receipts over current Expenditure in that year was
£546 1*. Ad.
The Council are glad to report that the Invested Funds of
the Society have now reached the sum of £10,729 11*., and they
feel that the time has arrived when the question of safeguarding
by investment the interests of Compounders may be reopened.
It may be mentioned here that the London and North-western
Railway Company, having obtained the necessary powers, converted
their 4C/C Debenture Stock (in which the Murchison Geological Fund
was invested) into a 3% similar stock, at the rate of £133 6*. S<f.
for every £100 of the former. A small amount was expended out
of the Society's general funds to make up an even £, and the amount
of Stock now held for the Murchison Trust Account is £1334.
The Council have pleasure in announcing the completion of
Volume XLIX. and the commencement of Volume L. of the
Society's Journal. In the preface to the first volume of the Journal,
issued in 1845, the hope was expressed that here was the com-
mencement of a series extending over many years. That hope has
been fulfilled, and it will be the endeavour, as it is the desire, of
the Council to maintain in the future the same high standard as
that which has distinguished the Society's Journal during its first
half-century.
The following awards of Medals and Memorial Funds have been
made by the Council : —
The Wollaston Medal is awarded to Geheimrath Professor Karl
Alfred von Zittel, For.Memb.G.S., in recognition of the important
services rendered by him to Geological Science, especially in the
department of Paleontology.
The Murchison Medal, together with a sum of Ten Guineas from
the Proceeds of the Fund, is awarded to Mr. "W. Talbot Aveline,
F.G.S., in recognition of the value of his work amongst the ancient
rocks of the British Isles.
The Lyell Medal, and a sum of Forty-six Pounds from the Proceeds
of the Fund, is awarded to Professor John Milne, F.R.S., in testimony
of appreciation of his investigations in Seismology.
Digitized by Google
12
PROCEEDINGS OF THE GEOLOGICAL SOCIETT
^May 1894,
The Balance of the Proceeds of the Wollaston Donation Fund is
awarded to Mr. Aubrey Straban, M.A., F.G.S., in token of appre-
ciation of bis work among the stratified rocks of England and
Wales, and for the purpose of assisting him in further researches.
The Balance of the Proceeds of the Murchison Geological Fund
is awarded to Mr. George Barrow, F.G.S., in recognition of the
value of his work among the older rocks of Scotland, and in order
to aid him in the further prosecution of his investigations.
The Balance of the Proceeds of the Lyell Geological Fond is
awarded to Mr. William Hill, F.G.S., as a testimony of the value
of his work among the Cretaceous rocks, and to aid him in further
researches.
From the Proceeds of the Barlow-Jameson Fund a sum of Tweuty-
fivo Pounds is awarded to Mr. Charles Davison, M.A., in token of
appreciation of his work in Seismology, and in order to aid him in
further investigations.
Report op the Library and Mrsrox Committee *or 1893.
Library.
Your Committee have great pleasure in announcing that many
valuable additions have been made to the Library during the past
year, both by donation and by purchase.
By Donation the Library has received about 183 Volumes of
separately published works and Survey Reports, 221 Pamphlets, and
248 Volumes and 31 detached Parts of the publications of various
Societies. Besides these, 16 Volumes of Newspapers have been
received. The total addition to the Society's Library by donation
amounts, therefore, to 447 Volumes, 31 Parts, and 221 Pamphlets.
Moreover, 15)9 Sheets of Maps and Sections have been presented to
the Library, and the Society may be congratulated on the fact that
its collection of the one-inch maps of H.M. Geological Survey is now
as nearly complete as possible.
The Books and Maps which have just been enumerated were the
gift of 114 Personal Donors, 23 Editors or Publishers of Periodicals,
216 Societies, and 36 Survey Departments and other Public Bodies
— the total number of Donors being 389.
By Purchase, on the recommendation of the Standing Library
Committee, the Society's Library has been enriched by the addition
of 84 Volumes of separately published works, 36 Volumes and
44 Parts of works published serially, and 31 Sheets of Maps.
It is a matter of satisfaction to your Committee that further
progress has been made during the twelvemonth under review
towards completing long-standing deficiencies in the sets of serials
in the Library.
Digitized by Google
Vol. 50.] A OTTO All BE PORT. 1 3
Among the sets which have heen completed by donation from
the respectire Institutions are the Transactions of the American
Institute of Mining Engineers, the Bulletin of the Essex Institute
and Memoirs of the Peabody Academy, and the Proceedings of the
Dorset Natural History and Antiquarian Field Club. Among the
sets which have been completed, or nearly completed, by purchase
are the Reports of the Arkansas and Illinois Geological Surveys,
and the Transactions of the Californian Academy of Science. More-
over, your Committee recommended the purchase of a fine copy of
Sowerby's 4 Mineral Conchology,' in seven volumes (as originally
issued).
The total amount expended on the Society's Library during 1893
is as follows : —
£ a. d.
Books, Periodicals, etc., purchased .... 108 18 2
Cost of Binding 15 1 7
Cards for Map Catalogue 1 0 0
Total £224 19 9
A new Manuscript Card Catalogue of the Geological Maps and
Sections in the Library has been commenced, and will probably be
completed early in the present year.
The Society's collection of the portraits of eminent geologists ha9
been enriched by the donation from Professor Preatwich of a large
framed photograph of himself.
Museum.
No additions have been made to the collections during the past
year. The work of labelling in a distinctive manner and regis-
tering the type- and other important specimens has been continued
by Mr. C. Davies Sherborn. During 1893 he went through 13b
drawers of specimens.
The expenditure on the Museum amounted to £16 9*. com-
prising the following items : —
£ 8. d.
Special work at the Museum 15 0 0
Sundries 1 9 3
£16 9 3
Digitized by Google
14 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Comparative Statement op the Number op the Society at the
CLOSE OP THE YEARS 1892 AND 1893.
Dec. 31, 1892. Dec 31, 1893.
Compounders 311 305
Contributing Fellows 896 873
Non-contributing Fellows . . 114 97
1321 1275
Foreign Members 39 40
Foreign Correspondents .... 40 38
1400 1353
Comparative Statement explanatory of the Alterations in the Number
of Fellows, Foreign Members, and Foreign Correspondents at the
clou of the years 1892 and 1893.
Number of Compounders, Contributing and Non-
contributing Fellows, December 31st, 1892 . .
Add Fellows elected during the former year and
paid in 1893
Add Fellows elected and paid in 1893
1360
Deduct Compounders deceased 10
Contributing Fellows deceased 24
Non-contributing Fellows deceased 8
Contributing Fellows resigned 16
Compounders removed 2
Contributing Fellows removed 16
Non-contributing Fellows removed 9
— 85
1275
Number of Foreign Members and Foreign ) ^
Correspondents, December 31st, 1892 . . j 4
Deduct Foreign Members deceased 3
Foreign Correspondents deceased . . 3
Foreign Correspondents elected 1 ^
Foreign Members J
— 10
69
Add Foreign Members elected 4
Foreign Correspondents elected 5
— 78
13T>3
Digitized by Google
Vol. 50.]
ANNUAL BEPORT.
Austin, C. E., Esq.
Becher, H. M., Esq.
Davis, J. W., Esq.
Leslie, A.t Esq.
Marshall, A., Esq.
Deceased Fellows.
Compounders (10).
Masey, T. A., Esq.
Potter, W. A., Esq.
St. Oswald, Lord.
Tyndall, Prof. J.
I Woodd, C. H. L., Esq.
Resident and other Contributing Fellows (24).
Anderson, Sir J.
Blanford, H. F., Esq.
Burnett, R. T., Esq.
Chaplin, J. C, Esq.
Cheetham, W., Esq.
Crosskcy, Rev. Dr. J.
Dahll, T., Esq.
Elliot, Sir G.
Hawksley, T., Esq.
Head, J. W., Esq.
Hewitt, J. R., Esq.
Hodges, E., Esq.
Homer, C. J., Esq.
Luxmoore, E. B., Esq.
Millie, J., Esq.
Northbourne, Lord.
Parry, T. S., Esq.
Paterson, J., Esq.
Shruhsole, O. W., Esq.
Smith, S. J., Esq.
Spencer, J., Esq.
Taunton, J. H., Esq.
Tremenheere, H. S., Est].
Yockney, S. H., Esq.
Non-contributing Fellows (8).
Blomefield, Rev. L.
Charlesworth, E., Esq.
Colquhoun, J., Esq.
Cooksey, J., Esq.
Denton, J. B., Esq.
Elphinstone, Sir H.
Fletcher, Col. T. \V.
Pritchard, Rev. C.
Foreign Members (3).
Keyserling, Count A. von. Stur, Dr. D.
Kokscharow, Mnj.-Gen. N. von. |
Foreign Correspondents (3).
Lossen, Prof. K. A. I Vilanova y Piera, Prof. J.
Seuft, Dr. F.
i6
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Bidder, P. B., Esq.
Collins, H. R., Esq.
Crimp, W. S., Esq.
Floyer, E. A., Esq.
Fordham, H. G., Esq.
Hardern, Rev. T. B.
Mackenzie, G. W., Esq.
Myhill, C, Esq.
Fellows Resigned (16).
North, S. W., Esq.
Price, T. J., Esq.
Sleeman, Rev. P. R.
Spencer, J. P., Esq.
Sugg, H., Esq.
Thomas, G. F., Esq.
Thompson, C. G., Esq.
Yeats, Dr. J.
Fellows Removed (27).
Butler, C. A. V., Esq.
Cairncs, E. M., Esq.
♦Calder, J., Esq.
Cheadle, R. W., Esq.
Clarke, A. W., Esq.
Couchman, Lieut.-Col. T.
♦Cunningham, G., Esq.
♦Dickson, J., Esq.
Diggens, J., Esq.
Dobson, A. D., Esq.
♦Even, J. B., Esq.
Griffiths, G. S., Esq.
♦Hare, J., Esq.
♦Holl, W., Esq.
* Removed from the list after having remained thereon for many years with-
out any known address.
♦Hunter, W. P., Esq.
Jones, D. W., Esq.
Kekewich, G. 0., Esq.
♦Laing, J. T., Esq.
M ay bury, Dr. A. C.
♦Mornay, A. F., Esq.
O'Donoghue, J., Esq.
•Robinson, A., Esq.
Skertchly, S. B. J., Esq.
♦Smith, H., Esq.
Stroud, Dr. J.
Thoreau, G. A. H., Esq,
Wonnacott, J., Esq.
The following Personages were elected from the List of Foreign Cor-
respondents to fill the vacancies in the List of Foreign Members
during the year 1893 : —
i
Professor Waldemar Christofer Brogger, of Christiania.
Monsieur Auguste Michel- L^vy, of Paris.
Doctor Edmund Mojsisovics von Mojsvar, of Vienna.
Doctor Alfred Gabriel Nathorst, of Stockholm.
The following Personages were elected Foreign Correspondents during
the year 1893 :—
Professor Marcel Bertrand, of Paris.
Professor Alexis Pavlow, of Moscow.
Monsieur Ed. Rigaux, of Boulogne -sur-Mer.
Doctor Sven Leonhard Tornquist, of Lund.
Doctor Charles Abiathar White, of Washington, D.C.
Digitized by Google
Vol. 50.]
ANNUAL REPORT.
After the Reports had been read, it was resolved : —
That they be received and entered on the Minutes of the Meeting,
and that such parts of thorn as the Council shall think fit be printed
and circulated among the Fellows.
It was afterwards resolved : —
That the thanks of the Society be given to W. H. Hudleston, Esq.,
retiring from the office of President.
That the thanks of the Society be given to Sir Archibald Geikie
and Dr. H. Woodward, rotiring from the office of Vice-Presidents.
That the thanks of the Society be given to Prof. J. F. Blake,
Prof. T. G. Bonney, K. Etheridge, Esq., Sir Archibald Geikie, and
Dr. H. Hicks, retiring from the Council.
After the Balloting-glasses had been duly closed, and the Lists
examined by the Scrutineers, the following gentlemen were declared
to have been duly elected as the Officers and Council for the ensuing
year : —
Digitized by Google
l8 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894.
OFFICERS.
PRESIDENT.
Henry Woodward, LL.D., F.R.S.
VICE-PRESIDENTS.
Prof. A. H. Green, M.A., F.R.S.
O. J. Hinde, Ph.D.
Prof. J. W. Judd, F.R.S.
It. Lydekker, Esq., B.A.
SECRETARIES.
J. E. Marr, Esq., M.A., F.R.S.
J. J. H. Teall, Esq., M.A., F.R.S.
FOREIGN SECRETARY.
J. W. Hulke, Esq., F.R.8.
TREASURER.
Prof. T. Wiltshire, M.A., F.L.S.
COUNCIL.
H. Bauerman, Esq.
W. T. Blanford, LL.D., F.R.S.
Sir John Evans, K.C.B., LL.D.,
F.R.S., F.L.S.
Prof. A. H. Green, M.A., F.R.S.
J. W. Gregory, D.Sc.
Alfred Harker, Esq., M.A.
G. J. Hinde, Ph.D.
T. V. Holmes, Esq.
W. H. Hudleston, Esq., M.A., F.R.S.,
F.L.S.
J. W. Hulke, Esq., F.R.S.
Prof. J. W. Judd, F.R.S.
Prof. C. Lapworth, M.A., F.R.S.
R. Lydekker, Esq., B.A.
Lieut.-Gene>al C. A. MeMahon.
J. E. Marr, Esq., M.A., F.R.S.
H. W. Monckton, Esq., F.L.S.
Clement Reid, Esq., F.L.S.
F. Rutlev, Esq.
J. J. H. Teall, Esq., M.A., F.R.S.
Prof. T. Wiltshire, M.A., F.L.S.
Rev. H. H. Winwood, M.A.
Henry Woodward, LL.D., F.R.S.
H. B. Woodward, Esq.
Digitized by Google
Vol. 50.] ANNUAL REPORT.
LIST OF
THE FOREIGN MEMBERS
OF THE GEOLOGICAL SOCIETY OF LONDON, in 1893.
Data of
flection.
1848. James Hall, Esq., Albany, Slate of New York, U.S.A.
1851. Professor James D.Dana, New Haven, Connected, U.S.A.
1863. Count Alexander von Keyserling, Raykiill, Russia. (Deceased.)
1866. Professor Robert Bunsen, For. Mem. RS., Heidelberg.
1857. Professor H. B. Geinitz, Dresden.
1867. Professor A. Daubree, For. Mem. U.S., Paris.
1871. Dr. Fr.inz Hitter von Hauer, Vienna.
1874. Professor Albert Gaudry, Paris.
1875. Professor Fridolin Sandberger, Wurzburg.
1876. Professor E. Beyrich, Berlin.
1877. Dr. Carl Wilhelm Giimbel, Munich.
1877. Dr. Eduard Suess, Vienna.
1879. Major-General N. von Kokscharow, St. Petersburg. (Deceased.)
1879. M. Jules Marcou, Cambridge, U.S.A.
1879. Dr. J. J. S. Steenstrup, For. Mem. R.S., Copenltagen.
1880. Professor Gusts ve Dewalque, Liige.
1880. Baron Adolf Erik Nordenskiold, Stockholm.
1880. Professor Ferdinand Zirkel, Leipzig.
1882. Professor Sven Love*n, Stockholm.
1882. Professor Ludwig Riitimeyer, Basel.
1883. Professor Otto Martin Torell, Stockholm.
1884. Professor G. Capellini, Bologna.
1884. Professor A. L. O. Des Cloizeaux, For. Mem. R.S., Paris.
1884. Professor J. Szabd, Pesth.
1885. Professor Jules Qosselet, Lille.
1886. Professor Gustav Tschermak, Vienna.
1887. Professor J. P. Lesley, Philadelphia, U.S^i.
1887. Professor J. 1). Whitney, Cambridge, U.S.A.
1888. Professor Pierre J. van Beneden, Louvain. (Deceased.)
1888. Professor Eugene Renevier, Lausanne.
1888. Baron Ferdinand von Richthofen, Berlin.
1889. Professor Ferdinand Fouque\ Paris.
1889. Marquis Gaston de Saporta, Aix-en- Provence.
1889. Geheimrath Professor Karl Alfred von Zittel, Munich.
1890. Professor Heinrich Rosenbusch, Heidelberg.
1890. Herr Dionys Stur, Vienna. (Deceased.)
1891. Dr. Charles Barrois, Lille.
1891. M. Gustave H. Cotteau, Auxerre.
1892. Professor Gustav Lindstrom, Stockholm.
1893. Professor Waldemar Chriatofer Brogger, Chrisfiania.
1893. M. Auguste Michel-Levy, Paris.
1893. Dr. Edmund Mojsisovics von Mojsvar, Vienna.
1893. Dr. Alfred Gabriel Nathorst, Stockholm.
Digitized by Google
20 PROCEEDINGS OV THE GEOLOGICAL BOCIETT. [May 1894,
LIST OF
THE FOREIGN CORRESPONDENTS
OF THE GEOLOGICAL SOCIETY OF LONDON, in 1893.
Date of
Election.
1863. Dr. F. Senft, Eisenach, {Deceased.)
1806. Professor Victor Raulin, Montfaucon <TArgonne.
1874. Professor Igino Cocchi, Florence.
1874. Dr. T. C. Winkler, Haarlem.
1877. Professor George J. Brush, New Haven, Connecticut, U.S.A.
1870. M. fidouard Dupont, Brussels.
1879. Dr. Etnile Sauvage, Boulogne-sur-Mer.
1880. Professor Alphonse Renard, Ghent.
1881. Professor E. D. Cope, Philadelphia, U.S.A.
1882. Professor Louis Lartet, Toulouse.
1882. Professor Alphonse Milne-Edwards, Paris.
1884. M. Alphonse Briart, Morlanwek.
1884. Professor Hermann Credner, Leipzig.
1884. Baron C. von Ettingshausen, Gratz.
1880. Professor J. Vilanova y Piera, Madrid. (Deceased.)
1887. Senhor J. F. N. Delgado, Lisbon.
1887. Professor A. Ileim, Zurich.
1887. Professor A. de Lapparent, Pans.
1888. M. Charles Brongniart, Paris.
1888. Professor Edward Salisbury Dana, New Haven, Connecticut, U.S.A.
1885. Professor Anton Fritsch, Prqgue.
1888. M. Ernest Van den Broeck, Brvxsrf*.
1880. Professor G. K. Gilbert, Washington, D.C., U.S.A.
1880. Dr. Hans Reusch, Chrittiania.
1889. M. R. D. M. Verbeek, Padang, Sumatra.
1890. M. Gustavo F. Dollfus, Paris.
1890. Herr Felix Karrer, Vienna.
1890. Professor Adolph von KOnen, Gottingen.
1890. M. Friedrich Schmidt, St. Petersburg.
1891. Senor Don Antonio del Castillo, Me.vico.
1891. Professor W. Dames, Berlin.
1891. Professor Emanuel Kayeer, Marburg.
1891. Professor Karl August Lossen, Berlin. (Deceased.)
1892. Professor Johann Lehmann, Kiel.
1892. Major John W. Powell, Washington, D.C., U.S.A.
1892. Professor George H. Williams, Baltimore, U.S.A.
1893. Professor Marcel Bertrand, Paris.
1893. Professor Alexis Pavlow, Moscow.
1893. M. Ed. Rigaux, Boulogne-sur-Mer.
1803. Dr. Sven Leonhsrd Tornquist, Lund.
1893. Dr. Charles Abiathar White, Washington, D.C., U.S.A.
Digitized by Google
Vol. 5o.]
ANNUAL REPORT,
21
AWARDS OF THE WOLLASTON MEDAL
UNDER THE CONDITIONS OP THE 'DONATION FUND '
ESTABLISHED BY
WILLIAM HYDE WOLLASTON, M.D., F.R.S., F.G.8., etc.
" To promote researches concerning the mineral structure of the earth,
and to enable the Council of the Geological Society to reward those
individuals of any country by whom such researches may hereafter be
made/' — "such individual not being a Member of the Council."
1831.
1835.
1836.
1837.
1838.
1839.
1840.
1841.
1842.
1843.
1844.
1845.
1846.
1847.
1848.
1849.
1860.
1861.
1852.
1853.
1854.
1855.
1856.
1857.
1858.
1859.
1860.
1861.
1862.
186;?.
Mr. William Smith.
Dr. G. A. Man tell.
M. Louis Agassiz.
i Capt. T. P. Cautley.
I Dr. H. Falconer.
Sir Richard Owen.
Professor C. G. Ehrenberg.
Professor A. H. Dumont.
M. Adolphe T. Brongniart
Baron L. von Buch.
I M. £lie de Beaumont.
I M. P. A. Dufrenoy.
Rev. W. D. Conybeare.
Professor John Phillips.
Mr. William Lonsdale.
Dr. Ami Boue\
Rev. Dr. W. Buckland.
Professor Joseph Prestwich.
Mr. William Hopkins.
Rev. Prof. A. Sedgwick.
Dr. W. II. Fitton.
I M. le Vicomte A. d'Archiac.
IM. E. de Verneuil.
Sir Richard Griffith.
Sir H. T. De la Beche.
Sir W. E. Logan.
M. Joachim Barrande.
1 Herr Hermann von Meyer.
I Mr. James Hall.
Mr. Charles Darwin.
Mr. Searles V. Wood.
Professor Dr. H. G. Bronn.
Mr. R. A. C. Godwin-Austen.
Professor Gustav Bischof.
1864. Sir R. I. Murchison.
1865. Dr. Thomas Davidson.
1866. Sir Charles Lyell.
1867. Mr. G. Poulett Scrope.
1868. Professor Carl F. Naumann.
1869. Dr. H. C. Sorby.
1870. Professor G. P. Deshayes.
1871. Sir A. C. Ramsay.
1872. Professor J. D. Dana.
1873. Sir P. de M. Grey Egerton.
1874. Professor Oswald Heer.
1875. Professor L. G. de Koninck.
1876. Professor T. H. Huxley.
1877. Mr. Robert Mallet.
1878. Dr. Thomas Wright.
1879. Professor Dernhard Studer.
1880. Professor Auguste Daubree.
1881. Professor P. Martin Duncan.
1882. Dr. Franz Ritter von Hauer.
1883. Dr. W. T. Blanford.
1884. Professor Albert Gaudry.
1885. Mr. George Busk.
1886. Professor A. L. O. Des
Cloizeaux.
1887. Mr. J. Whitaker Hulke.
1888. Mr. H. B. Medlicott.
1889. Professor T. G. Bonney.
1890. Professor W. C. Williamson.
1891. Professor J. W. Judd.
1892. Baron Ferdinand von
Richthofen.
1893. Professor N. S. Maskelyne.
1894. Gelieimrath Professor Karl
Alfred von Zittel.
VOL. L.
Digitized by Google
22
PROCEEDINGS OF THE 6BOLOOICAX BOCIETT. [May 1 894,
AWARDS
OF THK
BALANCE OF THE PROCEEDS OF THE WOLLASTON
'DONATION FUND.'
1831. Mr. William Smith.
1833. Mr. William Lonsdale.
ia34. M. Louia Agassiz.
1835. Dr. G. A. MantelL
1836. Professor G. P. Deshayea.
1838. Sir Richard Owen.
1839. Professor C. G. Ehrenberg.
1840. Mr. J. De Carle Sowerby.
1841. Professor Edward Forbes.
1842. Professor John Morris.
1843. Professor John Morris.
1844. Mr. William Lonsdale.
1845. Mr. Geddes Bain.
1846. Mr. William Lonsdale.
1847. M. Alcide d'Orbigny.
1848 \ ^aPeH)^00<^"^0Pe Fossils.
I M. Alcide d'Orbigny.
1849. Mr. William Lonsdale.
1850. Professor John Morris.
1851. M. Joachim Barrande.
1852. Professor John Morris.
1853. Professor L. G. de Koninck.
1854. Dr. S. P. Woodward.
1855. Drs. G. and F. Sandberger.
1856. Professor G. P. Deshayea.
1857. Dr. S. P. Woodward.
1858. Mr. James Hall.
1859. Mr. Charles Peach.
turn i Profe8801* T. Rupert Jones.
lt5W* ) Mr. W. K. Parker.
1861. Professor A. Daubree.
1862. Professor Oswald Heer.
1803. Professor Ferdinand Senft.
1864. Professor G. P. Deshayea.
1805. Mr. J. W. Salter.
1866. Dr. Henry Woodward.
1867. Mr. W. H. Baily.
1868. M. J. Bosquet "
1869. Mr. W. Carru there.
1870. M. Marie Rouault.
1871. Mr. R. Etheridge.
1872. Dr. James Croll.
1873. Professor J. W. Judd.
1874. Dr. Henri Nyst
1875. Mr. L. C. Miall.
1876. Professor Giuseppe Seguenza.
1877. Mr. R. Etheridge, Jun.
1878. Professor W. J. Sollas.
1879. Mr. Samuel Allport.
1880. Mr. Thomas Davies.
1881. Dr. R. H. Traquair.
1882. Dr. G. J. Hinde.
1883. Professor John Milne.
1884. Mr. E. Tulley Newton.
1885. Dr. Charles Callaway.
1886. Mr. J. S. Gardner.
1887. Mr. B. N. Peach.
1888. Mr. J. Home.
1889. Mr. A. Smith Woodward.
1890. Mr. W. A. E. Uasher.
1891. Mr. R. Lydekker.
1892. Mr. O. A. Derby.
1893. Mr. J. G. GoodchUd.
1894. Mr. Aubrey Strahan.
Digitized by Google
Vol. 50.]
ANNUAL REPORT
AWARDS OF THE MURCHISON MEDAL
AND OF THK
PROCEEDS OF THE * MURCHISON GEOLOGICAL FUND/
ESTABLISHED UNDER THE WILL OF THE LATE
SIB RODERICK IMPEY MURCHISON, Bart., F.R.S., F.G.S.
" To be applied in every consecutive year in such manner as the Council
of the Society may deem moat useful in advancing Geological Science,
whether by granting sums of money to travellers in pursuit of know-
ledge, to authors of memoirs, or to persons actually employed in any
inquiries bearing upon the science of Geology, or in rewarding any
such travellers, authors, or other persons, and the Medal to be given
to some person to whom such Council shall grant any sum of money
or recompense in respect of Geological Science."
1873. Mr. William Davies. Medal.
1873. Professor Oswald Heer.
1874. Dr. J. J. Bigsby. Medal.
1874. Mr. Alfred Bell.
1874. Professor Ralph Tate.
1875. Mr.W. J. Hen wood. Medal.
1875. Professor H. G. Seeley.
1876. Mr. A. R. C. Selwyn.
Medal.
1876. Dr. James Croll.
1877. Rev. W. B. Clarke. Medal.
1877. Professor J. F. Blake.
1878. Dr. H. B. Geinitx. Medal.
1878. Professor Charles Lapworth.
1879. Professor F. M'Coy. Medal.
1879. Mr. J.W. Kirkby.
1880. Mr. R. Etheridge. Medal.
1881. Sir Archibald Geikie. Medal
1881. Mr. F. Rutley.
1882. Professor J. Gosselet. Medal.
1882. Professor T. Rupert Jones.
1883. Professor H. R. Goppert.
Medal.
1883. Mr. John Young.
1884. Dr. H. Woodward. Medal.
1884. Mr. Martin Simpson.
1885. Dr. Ferdinand von Romer.
Medal.
1885. Mr. Horace B. Woodward.
1886. Mr. W. Whitaker. Medal.
1886. Mr. Clement Reid.
1887. Rev. P. B. Brodie. Medal.
1887. Mr. Robert Kidston.
1888. Professor J. S. Newberry.
Medal.
1888. Mr. Edward Wilson.
1889. Professor James Geikie.
Medal.
1889. Professor G. A. J. Cole.
1890. Professor Edward Hull.
Medal.
1890. Mr. E. Wethered.
1891. Professor W. C. Brogger.
Medal.
1891. Rev. R. Baron.
1892. Professor A. H. Green.
Medal.
1892. Mr. Beeby Thompson.
1893. Rev. 0. Fisher. Medal.
1893. Mr. G. J. Williams.
1894. Mr. W. T. Aveline. Medal.
1894. Mr. George Barrow.
c 2
Digitized by Google
24
PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
AWARDS OF THE LYELL MEDAL
A5D OF
PROCEEDS OF THE 'LYELL GEOLOGICAL FUND/
ESTABLISHED UNDER THE WILL AND CODICIL OF THE LATE
BIB CHAKLKS LYELL, Ba»t., F.R.S., F.G.8.
The Medal " to be given annually " (or from time to time) " as a mark of
honorary distinction and as an expression on the part of the governing
body of the Society that the Medallist (who may be of any country
or either sex) has deserved well of the Science/* — "not less than
one third of the Annual interest [of the fund] to accompany the
Medal, the remaining interest to be given in one or more portions at
the discretion of the Council for the encouragement of Geology or
of any of the allied sciences by which they shall consider Geology
to have been most materially advanced, either for travelling expenses
or for a memoir or paper published, or in progress, and without refer-
ence to the sex or nationality of the author, or the language in which
any such memoir or paper may be written."
1876. Professor John Morris. 1886.
Medal. 1886.
1877. Dr. James Hector. Medal. 1887.
1877. Mr. W. Pengelly. 1887.
1878. Mr. G. Busk. Medal. 1888.
1878. Professor W. Waapeu.
1879. Professor Edmond Hubert. 1888.
Medal. 1888.
1879. Professor H. A. Nicholson. I 1889.
1879. Dr. Henry Woodward.
1880. Sir John Evans. Medal. 1889.
1880. Professor F. A. von Quen- 1890.
stedt.
1881. Sir J. W. Dawson. Medal. 1890.
1881. Dr. Anton Fritsch. 1891.
1881. Mr. G. R. Vine.
1882. Dr. J. Lycett. Medal. 1891.
1882. Rev. Norman Glass. N 1891.
1882. Professor Charles Lapworth. • 1892.
1883. Dr. W. B. Carpenter. Medal. 1892.
1883. Mr. P. H. Carpenter. 1892.
1883. M. E. Rigaux. 1893.
1884. Dr. Joseph Leidy. Medal. 1893.
1884. Professor Charles Lapworth. 1893.
1886. Professor H. G. Seeley. 1894.
Medal.
1885. Mr. A. J. Jukes-Browne. 1894.
Mr. W. Pengelly Medal.
Mr. D. Mackintosh.
Mr. Samuel Allport Medal,
Rev. Osmond Fisher.
Professor IL A. Nicholson.
Medal.
Mr. A. H. Foord.
Mr. Thomas Roberts.
Professor W. Boyd Dawkina.
Medal.
M. Louis Dollo.
Professor T. Rupert Jones.
Medal.
Mr. C. Davies Sherborn.
Professor T. MeKenny
Hughes. Medal.
Dr. C. J. Forsyth-Major.
Mr. G. W. Lamplugh.
Mr. G. II. Morton. Medal.
Dr. J. W. Gregory.
Mr. E. A. Walford.
Mr. E. T. Newton. Medal.
Miss C. A. Raisin.
Mr. A. N. Leeds.
Professor John Milne.
Medal.
Mr. William Hill.
■ Digitized by Google
Vol. So.]
ANNUAL REPORT,
25
AWARDS OP THE BIGSBY MEDAL,
POUNDED BY THE LATE
Dr. J. J. BTGSBY, F.B.S., P.GJ3.
To be awarded biennially "as an acknowledgment of eminent services
in any department of Geology, irrespective of the receiver's country ;
but he must not be older than 45 years at his last birthday, thus
probably not too old for further work, and not too young to have done
much."
1877. Professor O. C. Marsh.
1879. Professor E. D. Cope.
1881. Dr. Charles Barrois.
1883. Dr. Henry Hicks.
1886. Professor Alphonse Renard.
1887. Professor Charles Lapworth.
1889. Mr. J. J. Harris Teall.
1891. Dr. George M. Dawaon.
1893. Professor W. J. Sollas.
AWARDS OF THE PROCEEDS OP THE BARLOW-
JAMESON FUND,
ESTABLISHED UNDER THE WILL OP THB LATE
Dr. H. C. BARLOW, F.G.S.
" The perpetual interest to be applied every two or three years, as may
be approved by the Council, to or for the advancement of
1880. Purchase of microscope.
1881. Purchase of microscope lamps.
1882. Baron 0. von Ettingshausen.
1884. Dr. James Croll.
1884. Professor Leo Lesquereux.
1886. Dr. H. J. Johnston-Lavis.
1888. Museum.
1890.
1892.
1893.
1894.
Mr. W. Jerome Ilarriaon.
Professor Charles Mayer-
Kymar.
Purchase of Scientific In-
struments for Capt. F. E.
Younghusband.
Mr. Charles
s
Digitized by Google
26 PROCEEDINGS OF THE GEOLOGICAL BOCTETT. [May 1 894,
Estimates for
INCOME EXPECTED.
£ s. d. £ ». d.
Compositions 106 0 0
Due for Arrears of Admission-fees 81 10 0
Admission-fees, 1894 157 10 0
180 0 0
Due for Arrears of Annual Contributions 84 0 0
Annual Contributions, 1894, from Resident Fellows, and
Non-residents, 1869 to 1801 1640 0 0
Annual Contributions in advance 35 0 0
Dividends on Consolidated 2| per Cents 100 13 0
Dividends on London and North-Western Railway 4 per
cent Consolidated Preference Stock 87 11 2
Dividends on London and South- Western Railway 4 per
cent. Preference Stock 108 19 4
Dividends on London, Brighton, and South Coast Railway
6 per cent. Consolidated Preference Stock 14 12 0
Sale of Quarterly Journal, including Longman's
account 165 0 0
Sale of Geological Map, including Stanford's
account 12 0 0
Sale of Transactions, Library-catalogue, Orme-
rod's Index, Hochstetter's ' New Zealand,' and
list of Fellows 5 0 0
182 0 0
£2646 15 6
THOMAS WILTSHIRE, Tbeasuheb.
January 24<ft, 1894.
Digitized by Google
Vol. 50.] FINANCIAL BEPORT. 2]
the Year 1894.
EXPENDITURE ESTIMATED.
£ a. d. £ i. d.
House Expenditure:
Taxes 5 8 4
Fire-insurance 15 0 0
Gas 30 0 0
Fuel 30 0 0
Furniture and Repairs 35 0 0
House-repairs and Maintenance 30 0 0
Annual Cleaning 15 0 0
Washing and Sundries 25 0 0
Tea at Meetings 15 0 0
200 8 4
Salaries and Wages, etc. :
Assistant Secretary 250 0 0
„ Half premium of life Insurance 10 15 0
Assistant Librarian and Aslant Clerk 270 0 0
House Porter and Upper-Housemaid, includ- j ^ ^ q
ing Uniform and Allowance for Washing... J
Under-Houseraaid, including Allowance to*"]^ 12 0
Washing /
Errand Boy 26 0 0
Charwoman and Occasional Assistance 12 0 0
Accountant's Fee 10 10 0
713 9 0
Official Expenditure :
Stationery 25 0 0
Miscellaneous Printing 30 0 0
Postages and other Expenses 90 0 0
145 0 0
Library (Books and Binding) 225 0 0
Museum 50 0 0
Publications:
Geological Map 6 0 0
Quarterly Journal 900 0 0
„ „ Commission, Postage,
and Addressing 100 0 0
List of Fellows 35 0 0
Abstracts, including Postage 110 0 0
1151 0 0
Balance in favour of the Society 61 18 2
£2546 15 6
N.B. — An expenditure of a sum of .£450 ha* been sanctioned for preparing
an Index to the Quarterly Journal. It is unlikely that any of this amount will
be expended during the present year, but if required, the balance brought
forward from 1893 will be available for the purpose.
Digitized by Google
28 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Income and Expenditure during the
RECEIPTS.
£ «. d. £ $. d.
Balance in Bankers' hands, 1 January, 1893. 311 1 9
Balance in Clerk's hands, 1 January, 1893 . 16 18 1
327 19 10
Compositions 186 18 0
Arrears of Admission-fees 37 16 0
Admission-fees, 1893 207 18 0
245 14 0
Arrears of Annual Contributions 105 13 11
Annual Contributions for 1893, viz. :
Resident Fellows 1645 17 6
Non-Resident Fellows ... 14 3 6
1660 1 0
Annual Contributions in advance 49 17 6
Dividends on 2 J p. c. Consolidated Stock. . 100 17 3
„ L. & N. W. Railway Stock . . 87 13 1
„ L. & S. W. Railway Stock . . 109 1 8
„ L. B. & 8. C. Railway Stock . . 3 13 0
301 5 0
Taylor & Francis : Advertisements in Journal, Vol. 48 . . 15 4
Publications :
Sale of Journal, Vols. 1-48 95 10 3
Vol.49* 74 4 11
Journal Subscription in advance 16 4
Sale of Library Catalogue 1 5 0
Sale of Geological Map t 15 10 10
Sale of Orraerod's Index 2 2 0
Sale of Hoobstetter's ' New Zealand ' 6 0
Sale of Transactions 3 3 6
Sale of List of Fellows 6 6
193 5 4
Repayment of Income Tax under
Schedule C for the year 1892-93 7 8 9
*Due from Messrs. Longmans, in addition to the
above, on Journal, Vol. 49, etc 64 16 0
tDue from Stanford on account of Geological Map. .. 10 8 7
We have compared this statement
with the Books and Accounts presented
to us, and find them to agree.
(Signed) HORACE W. MONCKTON, } .
JOHN HOPKINSON, J Attd«°r'-
January 27th, 1894.
£3078 18 8
Digitized by Google
Vol. 50.] FINANCIAL EEPOBT. 20
Year ending December 31*/, 1893.
EXPENDITURE.
House Expenditure: £ s. d. £ s. d.
Taxes 4 4 6
Fire-insurance 15 0 0
Gas 24 4 7
Fuel 22 9 0
Furniture and Repairs 36 18 7
House-repairs 11 8 0
Annual Gleaning 9 11 0
Washing and Sundries ., 18 14 1
Tea at Meetings 14 3 5
156 8 2
Salaries and Wages, etc. :
Assistant Secretary 260 0 0
„ Half premium of Life Insuranoe 10 15 0
Assistant Librarian and Assistant Clerk ...270 0 0
House Porter and Upper-Housemaid, includ-
ing Uniform and Allowance for Washing
Under- Housemaid, including Allowance for '
Washing
Errand Boy 24 2 0
Charwoman and Occasional Assistance 6 13 0
Accountant's Fee 10 10 0
91 11 9
42 12 0
Official Expenditure :
Stationery 18 8 3
Miscellaneous Printing 31 7 1
Postages and other Expenses 66 16 11
706 3 9
116 12 3
Library 224 19 9
Museum 16 9 3
Publications :
Geological Map 5 15 10
Journal Vols. 1-48 8 4 9
., VoL 49 743 19 8
„ „ Commission,
Postage, and Addressing . 83 4 0
————— 827 3 8
List of Fellows 35 1 2
Abstracts, including Postage 107 18 11
Investment in £150 L. B. & S. C. Rail-
way 5 per cent. Consolidated Pref.
Stock, @ 166| 252 19 0
Investment in £150 L. B. <fe S. C. Railway
5 per cent. Consolidated Pref. Stock,
© 164| 249 16 3
Balance in Bankers' hands, 31 Dec. 1893 . . 356 1 2
Balance in Clerk's hands, 31 Dec. 1893 .. 15 4 9
984 4 4
502 15 3
371 5 11
THOMAS WILTSHIRE, Treasurer.
£3078 18 8
3<>
PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
* OX©
f— 1 1-*
C *
u
o
I
EH
ft
2
P
•<
O ^
P
z
o
I
a
1
It
2
O
c
CO
.8
a •*
<71
O C5
8 8
a
o
I
m
00
5 ^
S >
£ 2
©
©
(8
©
H
H
g
I— t
a
©
a
X g
— * Z-
CO
CD
^ © © © <N
te O 00 ©
-3
o
o
o
<J
H
00
p
at
fi
•J
««J
s
o
H
o
R
o
p
a
9 ',
it
o
•-9
O
©
<— r£
- 0 c
51
^2
P CN O
o cr. o
1
tr.
H
O
[JO
C ^ ©
■ ci .5 5
a o
S3 «
»-r-r ■ ©
it ® S a>
* "ill
o
o
o
o
c
i
eo
a)
'1
i 1
J
J3
^ o OS CO o
•JO«OCOi-hph
iJ lO T*l (— « CO
CN lO
1
fi
— T3
00
00
(N0»
1—1
<^
i
®
o
CO
o
p4
*.
6
.'•2
D
o
u
o
^ 5 _
X)
il
S
o
o
s>
CO
■S «» * a
©a . a
c5 ^ M
8 ©IB
— •
35 «
Digitized by Google
Vol 50.] FINANCIAL REPORT. 3!
Digitized by Google
32
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Award of the Wollaston Medal.
In handing the Wollaston Medal (awarded to Geheimrath
Professor Karl Alfred von Zittel, Por.Memb.G.8.) to Dr. Hewrt
Woodward, F.R.S., for transmission to the recipient, the President
addressed him as follows : —
Dr. Woodward, —
The Council of the Geological Society have this year awarded the
Wollaston Medal to Geheimrath Dr. Karl Alfred von Zittel, Pro-
fessor of Geology and Paleontology in the University of Munich, in
recognition of the important services which he has rendered to
paleontologies! science during a long period of time. Without
alluding in detail to his early work on Austrian geology, much
of which was published at Vienna, I wish to point out that, as
Oppel'8 successor at Munich, he has continued to advance our
knowledge of the Mesozoic fauna of Central Europe, and more
especially of the interesting passage-beds betwixt the Jurassic
and the Cretaceous ; whilst the memoirs which he has published
on these subjects derive additional value from their excellent
illustrations.
Twenty years have now elapsed since K. A. von Zittel joined the
expedition of Gerhard Bohlfs to the Libyan Desert, and his con-
tributions to the geology of that region are probably the most
important that have as yet appeared in relation to Egypt and the
adjacent countries. It was on his return from this expedition that
he commenced his magnum opus, * The Handbook of Palaeontology/
the first part of which was published in 1876 and the last part,
relating to the Mammalia, in 1893, thus occupying an interval
of 17 years of continuous labour. If proof were needed of
the thoroughness of his work, we obtain it in his treatment of
the fossil sponges, which he found in so chaotic a state that he
applied himself to working out their relations independently, and,
having discovered the key in the microscopic structure of their
skeletons, was thus enabled to establish a system of classification
which has been found equally applicable to recent forms.
It is scarcely necessary to remind you that our Wollaston
Medallist has occupied the Chair of Palaeontology at Munich
for 28 years, during which time he has not only perfected the
collections at the museum, but his personal teaching has attracted
to his lectures students from almost all parts of the civilized world.
Digitized by Google
Vol. 50.J AlWIVKBSABY MEETING WOLLA8TOK MEDAL. 33
I feel confident, therefore, that the selection of the Council will be
cordially endorsed both by the Fellows of our own Society and
by all, whether at home or abroad, who are interested in the
brilliant record of one of the foremost palaeontologists of the age.
Dr. Woodward, in reply, said : —
Mr. President, —
I feel sure that no award of the Wollaston Medal made by the
Council of this Society has ever been moro popular than that made
to Geheimrath K. A. von Zittel, and I only regret that his duties
as Dean of the Faculty in his University, and his daily lectures,
have prevented him from being present to receive the Medal in
person. I shall, however, be happy to convey to him your kind
expressions of appreciation for his work ; and I beg permission to
read to you, from a letter which I have received, the following
message addressed to yourself: —
" With respectful thanks I acknowledge the unexpected honour
with which the Council of the Geological Society has favoured me,
in awarding to me the Wollaston Medal. I need scarcely say how
highly I appreciate this distinction, conferred upon me by the most
competent of scientific juries. I am really proud to have reached
this highest aim for the ambition of every geologist, and I feel
particularly pleased to find among the late and present possessors of
the Wollaston Medal the name of H. G. Bronn, my first teacher in
palaeontology, and of Franz von Hauer, who directed my first steps
in geological field-work.
u If, through conscientious labour, I have been fortunate enough
to contribute somewhat to the promotion of our knowledge of
Palaeontology and Geology, I feel by your kindly recognition amply
rewarded for all the pains that I may have taken in my scientific
researches.
" I deeply regret that I am unable to thank you personally,
Mr. President ; but you may be sure that the honour which you
have bestowed upon me will be a strong incentive to make myself
more worthy of your confidence by further investigations in the
wide field of Palaeontology and Geology."
Digitized by Google
34
PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Award of the Wollaston Donation Finn).
The Peesident then presented the Balance of the Proceeds of the
Wollaston Donation Fund to Mr. Aubrey Strahan, M.A., F.G.S.,
addressing him in the following words : —
Mr. Strahan, —
The Council have this year awarded to you the Balance of the
Proceeds of the Wollaston Donation Fund, in token of appreciation
of your geological work in several parts of England and on the
Welsh Border. In solid geology you have especially distinguished
yourself amongst the Carboniferous rocks of the Pennine Chain and
of North Wales, whilst your contributions to our own Journal, on
more than one subject in connexion with the Mosozoic rocks, have
evinced the interest that you take in questions arising within your
own professional experience. The Glacial Drifts of the Welsh Border
and the Glaciation of South Lancashire have also come under
your notico in dealing with the difficult subject of Superficial
Deposits. Beyond any mere assistance which the Balance of the
Fund might render towards further research, the Council, by this
Award, desire to express their sense of the value of the work which
you have already accomplished.
Mr. Strahan replied as follows : —
Mr. President, —
In thanking you and the Council of the Geological Society for
this Award, I wish to express my deep gratification at being
honoured by your selection.
During my connexion with the Geological Survoy I have, from
the nature of the work, been engaged in so many different parts of
the country that I have been unable to concentrate my attention on
any one formation as closely as might have been the case, and have
been led to consider some of the wider problems of geology. I
trust, however, that my work has not been without service to those
engaged upon the more minute zonal divisions of strata.
In every district in which I have been occupied, geologists with
local knowledge have generously placed their observations at my
disposal. The only return I could make lay in producing the
results of my work as expeditiously and in as useful a form as
possible. I take this Award as an indication that I havo not been
wholly unsuccessful.
Digitized by Google
Vol. 50.] ANNIVERSARY MEETING — MURCHISON MEDAL.
35
A WARD OP THE MURCHISON MEDAL.
In presenting the Murchison Medal to Mr. William Talbot
Avblinb, F.G.S., the President addressed him as follows : —
Mr. Ave line, —
The Council have this year awarded to yon the Murohison Medal,
together with a sum of Ten Guineas, in recognition of the import'
anoe of your work as a geological surveyor. Nearly half a century
has elapsed since your first communication to this Society, in
conjunction with the late Sir Andrew Ramsay, on the structure of
portions of Wales. Later on, we find you engaged in mapping and
describing some of the Mesozoic Rocks of Central England, and it is
now rather more than thirty years since you commenced your work
on the Permian and Carboniferous of Nottinghamshire and Derby-
shire. Still more recently you were engaged, as district surveyor,
on the borders of the Lake Country, being associated with Prof.
Hughes, Mr. Tiddeman, and other well-known geologists. That
your supervision of the work then progressing has yielded excellent
results in relation to the survey of that difficult region is a matter
of notoriety.
Although it is some time since you retired from active employ-
ment, I feel sure that you will be gratified to find that the record
of former years is not overlooked by a generation of geologists, who
recognize the value of the work in which you had so large a
share.
Mr. Avblinb, in reply, said : —
Mr. President, —
It is with feelings of great gratification that I receive this Medal,
founded by my former chief, Sir Roderick Murchison, whoso friend-
ship and kindness I experienced during the time he was Director-
General of the Geological Survey, and in whose company I made some
very pleasant geological explorations.
I am very much pleased to think that my work on the Geological
Survey has been appreciated by the Council of this Society, and
that they should have thought me worthy of receiving this Medal.
Mr. President, I cannot let this opportunity pass without saying
a word as to another Director-General of the Geological Survey, the
distinguished successor of Sir Roderick Murchison — Sir Andrew
Digitized by Google
36 PROCEEDINGS OF THE GEOLOGICAL 80CIETT. [11 ay 1 894,
Kamsay, who for over forty years was a sincere friend of mine, and
to whom I owe so much for his ready assistance and advice when
ho was Director of the Geological Survey ; we have together worked
out many a knotty point in the geology of Wales and elsewhere,
tramping together many a mile of mountain and valley. I am sure,
if he were living now, he would have rejoiced at tho honour this
day conferred on me.
1 must add that among tho most pleasing results of receiving this
Medal are the kind congratulations which I have received from
my former colleagues.
Award op the Murchison Geological Fund.
The President then handed the Balance of the Proceeds of the
Murchison Geological Fund to Mr. George Barrow, F.G.S., address-
ing him as follows : —
Mr. Barrow, —
The Balance of the Proceeds of the Murchison Geological Fund
has been awarded to you by the Council as a testimony of the value
of your geological work both in Yorkshire and in Scotland. As
regards the former district, I would draw especial attention to your
description of the geology of North Cleveland. Since your transier
to tho Survey of tho South-east Highlands you have evinced a
remarkable aptitude for petrologies! studies, whilst your recent
paper in the 4 Quarterly Journal ' on the Muscovito-biotite Gneiss
of Glen Clova bids fair to rank high in that category. The
Council hope that this mark of appreciation may not only aid but
encourage you to further research in the same direction.
Mr. Barrow repliod in the following words : —
Mr. President, —
I beg to thank the Council for the unexpected honour that they
have done me in conferring this Award. In receiving it at your
hands, Sir, pleasant memories are revived of my early geological
days in East Yorkshire, when your writings were of much assist-
ance to me. In those happy times we had no difficulty in deciding
which way up the succession lay. But now, in working on the
Digitized by Google
Vol. 50.] ANNIVERSARY MEETING — LYELL MEDAL. 37
Highland Series, it is often difficult, if not impossible, to decide
this very elementary point, and ony kindly encouragement in such
work is most welcome. It is the more welcome as in this case it
is a recognition that my efforts so far are not entirely without
value.
Award of the Lvell Medal.
In handing the Lycll Medal (awarded to Prof. John Milne,
F.R.S.) to Prof. J. W. Judd, F.R.S., V.P.G.S., for transmission to
the recipient, the President addressed him as follows : —
Professor Judd, —
The Lyell Medal, with the sum of Forty-six Pounds, has been
awarded to Prof. John Milne, F.R.S., of the Imperial College of
Engineering, Tokio, Japan, in testimony of appreciation of his in-
vestigations in Seismology. It must ever be regarded as a fortunate
event, in the interests of science, when Prof. Milne went to reside
in Japan. Undoubtedly his opportunities in that oscillating region
have been great, but he has been fully equal to the occasion, and
may with justice be regarded as the founder of seismic science in
that country. His efforts in this direction are in part recorded in
the annual volumes of the Seismological Society of Japan, to which
he has always been one of the most important contributors. Stimu-
lated no doubt by this good example, the Government of Japan has
taken up the study of earthquakes by establishing some 700 stations
for observations, so that, to use Prof. Milne's own words, 44 pheno-
mena, which were formerly matters of hypothesis, are now no longer
unexplained."
It is indeed the eminently practical turn given by Prof. Milne to
the study of earthquakes which commends his work so effectually
to geologists, and ever since his seismic experiments, in conjunction
with Mr. Gray, and the reports published by the British Association
on the investigation of the Earthquake Phenomena of Japan,
Prof. Milne has been recognized as one of the leading authorities
in this branch of science. Bearing in view, also, the delicate and
costly nature of seismological apparatus, the Council feel justified
in awarding a considerable sum of money, out of the Fund, to
accompany this Medal.
vol. l. d
Digitized by Google
3«
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
[May 1894,
Prof. Judd, in reply, said: —
Mr. President, —
Although I rise at short notice, it is with extreme satisfaction
that I receivo at your hands this Award to Prof. Milne. It was
my good fortune to he acquainted with the recipient of this Medal
and Fund before he loft this country for Japan ; and during his
long residence in that distant land I have had the privilege of fre-
quent correspondence with him. The choerful courage with which
he has faced unpromising surroundings, the resourceful tact with
which he has met every difficulty, and the unconquerable energy
with which he has surmounted the greatest obstacles, are known to
all of us. You, Sir, have referred to the admirable work done
by the Seismological Society of Japan, and it is not too much to
say that during a long period Prof. Milne might have justly
asserted "I am the Seismologies! Society." The foundation of
that Society and the Seismologies! Magazine was due to the wise
foresight and the unflagging energy of Prof. Milne himself, and
to the efforts of the pupils whom he has instructed, and whose
enthusiasm he has fired. I feel assured that the Fund which you
have asked mo to place in his hands will be administered in the
best interests of Geological Science. It was my good fortune to
know, very intimately, the founder of this Medal and Fund, and I
am persuaded that the Council of this Society never more truly
fulfilled his wishes and never more fully conformed to the terms of
his bequest — both in their letter and spirit — than when they
decided to make this Award to Prof. John Milne.
AWABD OP THE LyELL GEOLOGICAL FUND.
The President then presented the Balance of the Proceeds of the
Lyell Geological Fund to Mr. William Hill, F.G.S., and addressed
him in the following words :—
Mr. William Hill, —
The Balance of the Proceeds of the Lyell Geological Fund has
been awarded to you in testimony of the value of your work
amongst the Cretaceous rocks of this country during the last eight
years. In collaboration with Mr. Jukes-Browne, you have made
Digitized by Google
Vol. 50.] ANNIVERSARY MEETING BARLOW-JAMESON FUND. 39
communications to this Society on the Upper Cretaceous strata of
East Anglia, which are recognized as being of the highest importance.
Similar investigations, moreover, were prosecuted by yourself alone
with equal success in Lincolnshire and Yorkshire. Your intimate
acquaintance with the lithologioal characters of the various
members of the series has materially aided your stratigraphical
and palfflontological knowledge in arriving at correct results. It is
hoped that this acknowledgment of your services to Geological
Science may encourage you to continue your researches.
Mr. Hill replied as follows : —
Mr. President, —
f. desire to convey my heartiest thanks to the Council of this
Society for the Award which you have just placed in my hands.
My geological work has been undertaken chiefly to fill my spare
time, and I feel my reward ample in the pleasure which geological
study has given me, and in the kindly reception of my papers at
the hands of this Society. The unexpected honour you confer is to
me more gratifying than I can well express.
You have spoken of the value of my work, but I must not forget
that this is much enhanced by the help which I have received from
many Fellows of the Society, and especially from one who is not often
with us. I take this opportunity of thanking them most heartily. I
need hardly say, Sir, that the Award will stimulate me to further
efforts in the cause of Geological Science.
Award op the Barlow-Jameson Fund.
In handing a portion of the Proceeds of the Barlow-Jameson
Fund to Mr. Charles Davison, M.A., the President addressed him
as follows : —
Mr. Davison, —
A sum of Twenty-five Pounds from the Proceeds of the Barlow-
Jameson Fund has been awarded to you in token of appreciation of
your work in geological dynamics — including under that term the
study of earthquakes. In this connexion I would more especially
d2
Digitized by Google
40 PROCEEDINGS OP THE 6E0L06ICAL SOCIETT. [May l894T
allude to your valuable notice of the Inverness earthquakes of 1890.
wherein your conclusions with reference to the Great Glen of Scotland
open out views of the utmost importance in relation to the Highland
faults. We are also indebted to you for calculations on the
movement of scree-material, baaed on the expansion of the stones
through heat.
Geologists, I may Bay, are always glad to receive assistance from
mathematicians, and it is to be hoped that this acknowledgment on
the part of the Council of the value of your work may have the
effect of stimulating you to further study in that direction.
Mr. Davison, in reply, said : —
Mr. President, —
If anything could add to the welcome and gratifying character of
this Award, it would be the words of kindness and encouragement
that have accompanied it. For both I beg to tender my sincere
and hearty thanks. I have been told, Sir, and in my own case I
feel sure it must be so, that the Council in awarding these Fund*
look not so much to the past as to the future. I wish I could do
more than assure the Council that my best efforts will be used to
prevent their kindly hopes from being disappointed.
Digitized by Google
Tol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
41
THE ANNIVERSARY ADDRESS OF THE PRESIDENT,
W. H. Hudleston, Esq., M.A., F.R.S., F.L.S.
Gentlemen, —
Our losses through death have again been very considerable, and
although few of those whom we deplore were at any time actively
engaged in the work of the Sooiety, yeb the number of Fellows,
deceased since the last Anniversary, who had achieved distinction
in other branches of science must be regarded as noteworthy.
John Thrall, F.R.S., Honorary Professor of Natural Philosophy
at the Royal Institution, was born near Carlow on the 21st August,
1820, being descended from an old English family of that name, a
branch of which had migrated to Ireland in the days of the Stuarts.
At 19 years of age he joined the Ordnance Survey under Col. Owen
Wynne, and was afterwards employed as a surveyor during the
press of railway construction in England. In 1847, when the
railway mania had somewhat abated, he accepted an educational
post at Queenswood College in Hampshire. The following year, in
company with Dr. Frankland, Mr. Tyndall went to the University
of Marburg, where he enjoyed the advantage of the instruction and
co-operation of such men as Bunsen and Knoblauch. About 1853
ho joined the staff at the Royal Institution, having been elected a
Fellow of the Royal Society a year previously. His career at the
Royal Institution is too well known to need repetition here. It is
enough to indicate that, on the proposal of Faraday, Tyndall was
appointed Professor of Physics, and he held the post until 1887,
having been throughout that long interval one of tho most popular
and effective of lecturers.
On his retirement from this chair a complimentary dinner was
given to Prof. Tyndall, which was attended by a large number of
distinguished men. Since that date he withdrew to a very great
extent from public scientific work, having rotired to his chosen
abode on Hind Head, where, but for the encroachments of his
neighbours, he was content to pass a quiet time. Here it was, that
owing to the results of an unfortunate mistake, he died on the 4th
December, 1893, in the 74th year of his age. On the 15th of the
same month a special general meeting of the Members of the Royal
Institution was held for the purpose of passing a vote of sympathy
Digitized by Google
42 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1894,.
and condolence "with Mrs. Tyndall on the occasion of her husband's
death.
It is not for us to consider the work of Tyndall as a physicist,
though it will be readily conceded that his powers as a scientific
expositor have hardly ever been equalled. Although he joined this
Society in 1868, it cannot be said that he ever took any active part
in the study of geology, nor has he ever contributed a paper to our
publications. But there havo been certain problems more or less
connected with geological science to which he turned his ever active
mind, and to which brief allusion may be made, though these relate
to work achieved long ago. A notice of Tyndall's ideas on the
subject of slaty cleavage may be found in the introduction to his
famous work, ' The Glaciers of the Alps/ first published in 1860.
Well-nigh forty years have elapsed since that memorable visit to the
Penrhyn Slate Quarries, where his interest was aroused by what he
saw of the phenomena of slaty cleavage. He tells us he there found,
on enquiry, that the subject had already attracted the attention
of three English writers, Prof. Sedgwick, Mr. Daniel Sharpe, and
Mr. Sorby. Through Sedgwick he learned that cleavage and strati-
fication were things totally distinct from each other, but he was
obliged to disagree with his learned preceptor on the point that
slaty cleavage is of the same nature as crystalline cleavage. Tyndall
was not long in giving his adhesion to the mechanical theory,
and he justly remarked that science was indebted to Sharpe and
Sorby for the prime facts on which that theory rests. In another
department Tyndall's glacier work has been of great service to
geologists for the last five and thirty years, though not in itself
devoted, to any considerable extent, to the solution of geological
problems. He is credited with a belief that glaciers were possessed
of considerable excavating power, contrary to doctrines which have of
late prevailed. Nevertheless the whirligig of time brings old fashions
back again, and thus it comes to pass that the lake-basin theory has
lately had some able advocates. Tyndall also took an interest in
the subject of the Parallel Beads of Glen Boy, and was a supporter of
Jamieson's glacier-dam theory, though he never took any trouble
to ventilate these opinions in the geological literature of the day.
The Bev. Charles Pritchabd, F.B.S., Professor of Astronomy in
the University of Oxford, was born about the year 1810. He
graduated at St. John's College, Cambridge, where he took his degree
as fourth wrangler, being also a Fellow of his College. For many
Digitized by Google
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
43
years he was head master of the Clapham Grammar School, and in
1870 was elected to the Savilian Chair at Oxford. His contributions
to astronomical science aro well known, and in 1886 he was awarded
the gold medal of the Royal Astronomical Society for his Uranometria
If ova Oxoniensis. Ho became a Fellow of this Society in 1852, but
does not appear to have contributed papers or taken any active part
in its work. Dr. Pritchard died at his house in Oxford on the 28th
May, ] 893, in his 84th year.
Thomas Hawksley, F.R.S., M.InstC.E., was born in 1807 at
Nottingham, for which town he was appointed to construct water-
works about the year 1830. Subsequently he became so famous in
this line of business that he is said to have constructed above one
hundred and fifty, many of them large undertakings. To his
ingenuity we owe the system of * constant service ' water-supply.
He also rendered great help to Sir Joseph Bazalgette in connexion
with the main drainage of London, and gave on more than one
occasion important ovidence with reference to the water-supply
of the metropolis. Mr. Hawksley was elected a Fellow of this
Society in 1870, though he never contributed a paper or took any
activo part in our Proceedings. Yet it may well be supposed that
he frequently encountered questions essontially geological, when
deciding on the sites of storage-reservoirs, and especially in deter-
mining how deep to carry the puddle- walls below the valley-bottom.
In such cases he usually availed himself of the advice of skilled
geologists, and, as a result of the sinking of trial-shafts, was some-
times able to detect slight errors in the published maps, which he
was always ready to notify to the proper quarter.
Mr. Hawksley, who was President of the Institute of Civil
Engineers in 1872-1873, must ever be regarded as one of the most
eminent engineers of this country. He died in London on the 23rd
September, 1893, at the age of 86.
Edward Bouvbrie Luxmoore, M.A., was born about 1829 at
March wiel, in Denbighshire, and was educated at Eton and Trinity
College, Cambridge. For many years he resided at Bryn Asaph,
near St. Asaph, and was a Justice of the Peace for Flintshire.
Although Mr. Luxmoore does not appear to have written any-
thing on geology himself, he took a great interest in the science.
His hospitable mansion was well known to geologists visiting the
neighbourhood, and he was well informed on the geology of
Digitized by Google
44 PROCEEDINGS OF THE 6 KG LOGICAL SOCIETY. [May 1 894,
Denbighshire and Flintshire. In 1883-84 Mr. Luxmoore began 011
his own account the exploration of the Caves at Ff ynnon Beuno and
Cae Gwyn, and during the exhaustive work carried on under grants
from the Royal Society and the British Association, from 1885-87,
he rendered great assistance, and was one of the committee. In
1887 he was elected a Fellow of this Society. He died very
suddenly at Locarno, in Italy, on March 27th, 1893, at the age of
63.
Charles Edward Austin, AssocM.InstCE., was born at Wotton-
under-Edgo on the 22nd June, 1819. As a young man he was
engaged under Brunei in the construction of the Great Western
Railway, which was opened through to Bristol in 1841. After-
wards he resided in Russia, devoting his attention to the steam-
navigation of the Volga. He was elected a Fellow of this Society
in 1858, and four years later communicated some notes 'On
a locality in Siberia where Fossil Fish and Esthtria have been
found.' For many years he was enframed in the construction of
foreign railways, especially in Eastern Europe and Asia Minor. In
the latter country, about ten years ago, he worked a mining con-
cession at a considerable loss of time and money. He was also
engaged in enterprises for dealing with the sewage of towns, and
published treatises on the subject.
Mr. Austin died on the 8th April, 1893, aged 74 years.
Sir James Anderson was born at Dumfries in the year 1824.
Having received his early education in his native town, he entered
the mercantile marine at the age of 16, and ultimately rose to the
command of one of the Cunard line of steamships. His chief
scientific work was in connexion with the laying of the Atlantic
cable, when he was in command of the 4 Great Eastern.' In
November 1866 ho received the honour of knighthood on the
successful completion of that undertaking. About four years after-
wards he joined this Society, though I am not aware that he ever
took any active part in its work. Sir James Anderson died in
London on the 7th May, 1893, in his 69th year.
James William Davis, F.L.S., F.S.A., was born in the neigh-
bourhood of Leeds on the 15th April, 1846, and received his early
education at the grammar school of that town. When about
18 years old he accompanied his father's family to Halifax, where he
Digitized by Google
Vol. 50.]
ANNIVERSKKY ADDRESS OF THE PRESIDENT.
45
was one of tho successful stud on te at the Haley Hill College, having
taken the Society of Arts' silver medal for chemistry. This kind
of training was eminently suitable for the dyeing business, in
which his family was engaged ; but these matters did not absorb
the whole of young Davis's attention. When quite a schoolboy he
began collecting objects of natural history, and at a very early age
was elected secretary of the Leeds Naturalists' Society. And thus it
was that, throughout the whole of his most active life, business and
science were always combined, and he gonerally managed to do
ample justice to both.
Mr. Davis was about 27 years of age when, after having devoted
some time to archaeological and antiquarian pursuits, he joined this
Society in 1873. He had now become a confirmed geologist and
paleontologist, and during the twenty years that he was a Fellow
of the Geological Society contributed at least nine papers to its
* Proceedings,' — the first, in 1870, having been on a " Bone-bed in the
Lower Coal-measures, with an Enumeration of the Fish-remains of
which it is principally composed." His contributions to our own
publications, in fact, related chiefly to fishes of Carboniferous age,
which he had made his especial study.
Among his contributions on fossil ichthyology to various other
scientific societies may be mentioned the monographs published by
the Royal Dublin Society — ' On the Fossil Fishes of the Mountain
Limestone of Great Britain ' (1883) ; * On the Fossil Fishes of the
Chalk of Mount Lebanon and Syria' (1887); and 1 On the Fossil
Fishes of the Tertiary and Cretaceo-Tertiary Formations of New
Zealand' (1888). In order to bring out such works as these
their Author, besides drawing on the resources of his own splendid
collection and on those of the museums of this country, was in the
habit of travelling extensively abroad, visiting museums, it may be
said, almost all over Europe. Of his energy and enthusiasm in the
cause there can be no doubt whatever, but if palaeontology is year
by year getting more into the hands of the trained specialist, this is
emphatically the case with such obscure and difficult subjects as are
presented by the fossil vertebrata of the older formations.
We must now consider Davis as a geologist, more especially
in connexion with his native county. It was owing to his exertions
that the Yorkshire Geological and Polytechnic Society became an
important and useful body. Some twenty years ago that Society
was on the verge of dissolution. The advent of Mr. Davis to the
secretaryship changed this state of affairs, and, by dint of enthusiasm
A
46 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
and perseverance, he raised it to a prosperous and useful condition,
whilst the number of its members was nearly quadrupled. At the
jubilee meeting of the Society, held in Ripon in 1888, the oppor-
tunity was seized to present Mr. Davis with some mark of the
esteem in which he was personally held by the members, and also
in part recognition of his great services as honorary secretary and
editor of the ' Proceedings: It is scarcoly necessary to add that
Mr. Davis himself was a large contributor to those ' Proceedings ' ;
and in 1889 he wrote the history of the Society, constituting the
bulk of the tenth volume. He was also an active momber of the
Yorkshire Naturalists' Union, nor must his work on tho Geology of
West Yorkshire, in conjunction with Mr. Lees, be forgotten.
Mr. Davis became a member of the British Association in 1873,
and was a permanent member of their General Committee. His
communication on the Exploration of a Fissure in the Mountain
Limestone of Raygill was published in the Report for 1881, a fuller
account being given in the Proceedings of his own Society. It was
about this time that I had the pleasure of making Mr. Davis's
acquaintance, which speedily led to our undertaking the joint
directorship of the midsummer excursion of the Geologists' Asso-
ciation of London to the West Riding, where the Raygill fissure
was to be one of the objects of investigation. This was in 18S!2,
when I first learnt to appreciate Mr. Davis's methods and his
knowledge of the geology of the Craven district. At that time he
was especially interested in the group of erratics near Norber.
That Mr. Davis was not idle as a scientific writer may be inferred
from the fact that a list of 56 memoirs and papers of his is given in
the last volume of the * Geological Magazine ' (1893), several of them
having appeared originally in its numbers. But this is only one
side of the picture ; for Mr. Davis had a civic career such as few
subjects of Her Majesty ever attain to. For many years he was
distinguished as a public man, and especially as an advocate of
technical education ; and not content with promoting Mechanics'
Institutes and Halls, he oven commenced an agitation to form a York-
shire Fine Art Society, of which for some years he was secretary.
His house at Chovinedge, near Halifax, is said to have been rich in
the treasures both of science and art, and he had also got together
a considerable library. Anything rare or novel he was ready
to lend to the Halifax Museum or other local exhibitions : and
it is almost unnecessary to say that ho took great interest in the
Scientific Society of that town, of which society he was at one time
President.
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 47
Not to dwell too long upon his career as a citizen, it may be
sufficient to say that Mr. Davis was installed Mayor of Halifax in
November 1890, and it was in the following February that he
entered the Council of the Geological Society, serving on it for two
years. So pleased were his fellow-townsmen with their Mayor that
they elected him three times in succession to fill that office, and well
might it have been for him if his friends had been less exacting :
for the Nemesis which attends over-exertion had already cast a
shadow upon him, as nearly two years have now elapsed since
he first began to suffer from insomnia. Change of scene, so far as
his engagements would allow, was tried on different occasions with
partial success, and few would have conjectured when Mr. Davis was
with us at our last Anuiversary Meeting that his end was so near.
Later in the spring he went on a visit to Paris, and, not benefiting
much by the change, tried some rural districts in Yorkshire, finally
settling at his old quarters in Bridlington, where he died very
suddenly on July 21st, 1893, at the early age of 47.
Georob William Shrubsole was born at Favereham, in Kent, in
1827, and when a young man made his way to Chester, where he
resided for the past forty years in business as a chemist. He was
well known to his fellow-citizens in connexion with the Chester
Society of Natural Science, of which, along with the late Canon
KingBley, he was one of the founders. He was appointed first
Chairman of the Geological Section of that society, a post ho held
for twenty years, and was, moreover, their first Honorary Curator.
During this period he arranged and largely added to their collection
of Lower Silurian fossils from the Glyn Ceiriog district, in addition
to other work. He was also well known for the interest he took in
archaeological research.
Mr. Shrubsole becamo a Follow of this Society in 1873, and has
been in correspondence with the officers on more than one occasion,
notably when he succeeded in recovering some specimens of fossil
fishes belonging to our museum from tho waters of the Dee. In
biology and palaeontology he has principally worked among the
mollusca and some of the lowor invertebrates.
Mr. G. W. Shrubsole was one of three brothers, all of whom have
made communications to this Society in their capacity as Fellows.
He died at Chester on July 21st, 1893, at the age of 66.
Edward Charlesworth was born at Clapham, in Surrey, on the
13th September, 1813, being the eldest son of the Rev. John
Charlesworth, rector of St. Mildred, Bread Street, London. Much
48 PROCEKDDCGB OP THB GEOLOGICAL SOCIETY. [May 1 894,
of young Edward s early life was spent in Suffolk, where his father
was at that time rector of Flowton, near Ipswich, and he enjoyed
exceptional advantages in being able to visit the numerous Crag
pits and other excavations in that neighbourhood. On these
occasions the father encouraged his children to observe and collect
fossils, and thus they all more or less imbibed a love of geology,
which became especially strong in the eldest.
Cbarlesworth was educated at the private school of the Rev. W.
Kinchin, afterwards rector of St. Stephen's, Ipswich ; and the
medical profession having been chosen for his career, he was articled
to an eminent London physician and became a pupil attached to
Guy's Hospital. But his love of geology was stronger than his
liking for medicine, and the 6tudy of fossil bones had more
attractions for him than that of mere human anatomy. And thus
it came to pass that after his articles had expired he turned
to geology, and especially to palaeontology, with all his heart.
In 1835 he joined this Society, being then 22 years of age, and
about the same time gave proof of his excellent knowledge of the East
Anglian Crag in a paper published in the ' Philosophical Magazine,'
wherein the divisions now established were for the first time clearly
indicated. It was at this period likewise that he became connected
with the Zoological Society and the British Museum, where he held
responsible posts, besides being the proprietor and editor of
Loudon's « Magazine of Natural History.' He was also appointed
Honorary Curator of the Ipswich Museum, where some of his early
collections of Crag fossils are still preserved. But all these engage-
ments were unfortunately relinquished on his accepting an offer to
go out to Central America in 1840, under circumstances which
promised to be of great interest and importance in opening to him
a wide sphere for studying the geology of that region. The indis-
position of his fellow-traveller shortened that tour to a few months'
duration, and Mr. Charlesworth returned to resume his researches
in England.
His intimate acquaintance with the Crag now enabled him to
assume the position of chief authority in matters connected with
that formation, and his love of fossils, added to his undoubted
biological and palaeontologies! knowledge, caused him to extend his
interest to the splendid shells of the older Tertiaries in Hampshire
and the Isle of Wight. Probably no one rivalled him in arranging
and classifying geological collections in museums — a work he was
often called upon to undertake in addition to his literary labours.
Digitized by Google
Vol. 50.] AWNIVEB8ABT ADDRESS OF THE PRESIDENT.
49
Mr. Cbarlesworth in those days was never idle, though his some-
what contentious disposition, as evinced at the British Association
and elsewhere, not seldom involved him in disputes. Whon in this
mood he was quite as ready to attack men such as Owen and Lyell as
to fly at smaller game. Although at one time a prolific writer, his
communications to thiB Society were not numerous ; yet it is worthy
of record that he contributed a note on the genus Physeter (or
sperm-whale) in the Red Crag of Felixstowe to the first volume of
the Quarterly Journal, just half a century ago.
In the same year, viz. in 1844, Mr. Charlesworth was appointed
successor to Prof. John Phillips as curator to the museum of the
Yorkshire Philosophical Society at York. There he continued to
reside for 14 years, during which time he obtained a considerable
insight into the Jurassic and Carboniferous fossils for which York-
shire is so famous. Ho also spread throughout the county an
intorest in collecting, and was instrumental in keeping alive a taste
for geology. But, as his opinions on certain points wero too ad-
vanced for the more orthodox inhabitants of the ancient city, he
found it advisable to give up his post in 1858, returning once more
to London.
As a man of science, in the stricter acceptation of the term,
Charlesworth's career may be almost said to have terminated when
he threw up this appointment 36 years ago. He was still ablo to
utilize his unique knowledge of Crag and other Tertiary fossils, and
to this he added a curious interest in flints and their history ; but
on the whole his views may be said to have crystallized early, and
he took but little part in modern geological development. From
this time forth his energies were principally devoted to the buying
and selling of fossils. Not that he was a dealer in the ordinary
sense of the term, for he thoroughly understood the pakeontological
history of his wares, and could arrange and name a collection better
perhaps than any roan. Not unmindful of his former connexion
with the British Museum, he was ever anxious to supply that
establishment with the choicest things. But he generally had some
exquisite specimen, temptingly displayed on pink cotton wool in a
glass-topped box, for his private customers, of whom Mr. Reed, of
York, must always be deemed the chief.
The last 20 years of his life were greatly clouded by long and
severe illness, frequently confining him to his bed-room, and almost
entirely preventing him from doing anything in the way of searching
for fossils. During this interval he occasionally appeared at the
Digitized by Google
5o
TR0C
GS OP TIIE GEOLOGICAL SOCIETY.
[May 1894,
meetings of Societies, where his original fluency as a speaker never
deserted him, and where he would propound geological puzzles, or
descant on the origin of flint, as was lately the case at the Victoria
Institute. Quite recently, indeed, he was in the habit of attending
the meetings of that Socioty and participating in their discussions.
By this time he had retired to Saffron Walden, only occasionally
coming to London ; and when a prisoner through illness, his boxes
of fossils and his pamphlets and manuscripts of all descriptions used
to be heaped around his bed, almost filling up the room. A friend
estimated that there was a ton and a half of flint fossils in that
apartment at the time of his death. This event occurred at Saffron
Walden on the 28th July, 1893, when Mr. Charlesworth only
wanted a few weeks of completing his 80th year.
The Rev. Leonard Blomefield (originally Jenyns) was born in
London on the 2oth May, 1S00. being the son of the Rev. George
Leonard Jeuyns, of Bottisham Hall, near Cambridge. He received
his education at Putney, at Eton, and at St. John's College, Cam-
bridge, graduating in 1822. Young Jenyns was at all times an
ardent naturalist, and used, when a boy, to have rare birds sent to
him in London from the family estate at Bottisham. He was Charles
Darwin's senior by ten years when they hunted butterflies together
in the adjacent fen, and his early collections are in the museum of
the Cambridge Philosophical Society. He held the living of
Swaffham Bulbeck, in the same county, for at least thirty years.
Mr. Blomefield was elected a Fellow of the Linnean Society in
1822, and for many years distinguished himself in botany and
zoology. The * Fishes of the Voyage of the 4 Beagle,' * written at the
express request of his friend Darwin, was one of the works which
gave him the most satisfaction. He was also interested in meteoro-
logy, and one of the founders of the Entomological Society. There
is no record of his having paid any special attention to geology,
but he was elected a Fellow of this Society in December 1S35, the
certificate being signed by A. Sedgwick, J. S. Henslow, R. Mur-
chison, and W. Clift. He wrote a memoir of Prof. Henslow some
years afterwards. In 1871 the surname and property of Francis
Blomefield, the celebrated historian of Norfolk," devolved upon
Mr. Jenyns, who made Bath his residence during the later years of
his life. He was the founder and first President of the Bath
Natural History and Antiquarian Field Club, and the donor of the
Jenyns Library, a gift including his Herbarium of British Plants,
Vol. 50.]
ANNIVERSARY ADDRESS OP THE PRESIDENT.
51
the result of his life-work as a botanical collector. At the time of
his death Mr. Blomefield was the father of the Linn can Society,
having been a Fellow for over 70 years, and for nearly 59 years a
Fellow of this Society. He died at Bath on September 1st, 1893,
in his 94th year.
Harry Macdonald Becker, A.R.S.M., was born at Simla in 1855,
and educated at private schools in England until he reached the age
of 13, when ho was sent to Dresden. His education as a mining
engineer was commenced at Freiberg and completed at the Royal
School of Mines in Jermyn Street, where he became an Associate in
1875, and was the same year elected a Fellow of this Society.
Originally engaged by tho Borneo Company, Mr. Bechcr spent
many years in the Malay Peninsula and other parts of the far East,
during which he visited China and Japan and even Siberia, reporting
on coal-deposits in those regions. In 1883 he returned to China
for the purpose of investigating the mineral resources of Korea, and
subsequently established the first Chinese gold-mine and quartz-mill
in Chantung. The Christmas of 1887 found him in the jungles of
North-eastern Siam reporting on gold-mines there, and in the
following year he was engaged at the Pahang gold-mines, near
Singapore.
Mr. Becher several years ago contributed a note on some cupri-
ferous shales in the province of Hon-peh, China, to the Quarterly
Journal, and about a year ago he gave us a short paper on the gold-
quartz deposits of Pahang. He also read a paper on ' Mining in the
Malay Peninsula ' before the Institution of Mining and Metallurgy
when he was last in England.
Shortly after his return to the East Mr. Becher was unfortunately
drowned in fording one of the Malayan rivers, the news being
received in England with the most profound regret by a largo circle
of attached friends. This event took place on the 16th September,
1893, when he was only 38 years of age.
John Spencer was born in tho year 1821. He was by profession
a mining engineer, and about 25 years ago became a Fellow of this
Society. There is a short note of his in tho Quarterly Journal on
Boulders found in Coal-seams, and on the evidence of Ice-action in
Carboniferous times. He resided at Manchester, and died there on
September 20th, 1893, at the age of 72.
Digitized by Google
52 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
The Kev. H. W. Crosskey, LL.D., was born at Lewes, in Sussex,
on the 7th December, 1826. After some experience as a minister
in the Midlands, he accepted in 1852 the charge of an Unitarian
congregation at Glasgow, where he remained for 17 years. During
the whole of that period he evinced much interest in scientific
matters, being actively connected with the Philosophical and Geo-
logical Societies of that city. Subsequently he returned to Birming-
ham, where he resided for the last 24 years, always evincing an interest
in science and education. He was well known as an authority on
Glacial Geology, and the author of a valuable series of Reports on
the Erratic Blocks of this country, communicated during the past
20 years to the British Association. He became a Fellow of this
Society in 1868, and occasionally contributed papers on post-Tertiary
fossils. He also co-operated with Robertson and Brady in describing
the post-Tertiary Entomostraca in the Palteontographical Society's
volume for 1874.
Dr. Crosskey died at Edgbaston, near Birmingham, on the 1st
October, 1893, having nearly completed his 67th year.
John Bailey Denton, M.Inst.C.E., was born in November 1814.
In early manhood he was associated with Brassey and Locke in the
construction of the Great Northern and many other railways.
More than half a century ago he acquired celebrity by the enquiry —
still a very pertinent one — * What can be dono for British agri-
culture?' His fame as a drainer of soils is well known, and it
was, in all probability, the interest that he took in this branch
of practical Bcienco which induced him to join the Geological
Society. This step was taken in 1854, but Mr. Denton never made
any contribution to our Proceedings, nor participated in any way.
so far as I know, in the active work of the Society. Still there can
be little doubt that our publications were useful to an engineer
who devoted his attention for so many years to the storage of water,
and the methods of purifying sewage by means of percolation through
soil. Mr. Denton had been a Hertfordshire magistrate for upwards
of a quarter of a century, and died at Stevenage, in that county,
on November 10th, 1803, in the 79th year of his age.
John Plant, Major of Volunteers, was born in Leicester about
1820. Early in life he evinced a love of natural history, and assisted
in forming the local museum in his native town. In 1849 he was
selected by the Corporation of Salford as their librarian and curator
of the borough museum, duties which he discharged with great
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. 53
satisfaction to all for over 40 years. During this period he paid
considerable attention to geology, and wrote several papers, chiefly
for the Manchester Geological Society. He died early in January
1894, at the age of 74, and was buried at Rhosneigr, on the coast
of Anglesey.
Count Alexander ton Ketserling, Foreign Member of the
Geological Society, was born on the 15th August, 1815, at Kabellen,
in Courland. In early life he studied at the University of Berlin
under Humboldt, Von Buch, and other distinguished men of that
period. It was for this reason that, in 1841, he was selected
along with Lieut. Kokscharow to accompany Murchison and Do
Verneuil on their second tour in Rush i a, when geological obser-
vations were made in tho governments of Wilna, Courland, Livonia,
and Esthonia. He also remained with Murchison's party during the
special geological survey which was made by order of the Emperor
Nicholas, and the results of which were given to the world in * The
Geology of Russia and the Ural Mountains,' published in 1845.
In the year 1842 Yon Keyserling visited England and Prance
for the purpose of comparing the rocks of these countries, in the
field, with the rocks of Russia, and also to collect specimens for
the Institute of Mines at St. Petersburg. With this object he and
Murchison started from London and practically made the tour of
Great Britain in their endeavour to gather materials for the illus-
tration of their Russian work ; visiting amongst other places the
county of Durham, in order to compare the rocks and fossils of
that region with those of the Russian province of Perm. It was
in this year also, when Murchison was President of the Society,
that a joint paper by himself, De Verneuil, and Von Keyserling,
' On the Geological Structure of the Central and Southern Regions
of Russia and the Ural Mountains,' occupied three successive
meetings in its delivery.
In 1844 Von Keyserling was again with Murchison, who had been
charged to convey to the Emperor Nicholas a gold medal struck in
honour of his visit to the Queen of England. Further information
was then given by him to Sir Roderick for their great work on
the geology of Russia and the maps illustrating it. The subsequent
career of Von Keyserling is less directly connected with that of
English geologists ; but we find that he continued to be honoured
in his own country, where he was for some time connected with
the Imperial Corps of Mines, and, in 1859, was appointed Assistant
State Geologist. Between 1862 and 1869 he waa Dean of the
University of Dorpat, returning in the latter year to Raykiill, in
VOL. L. €
Digitized by Google
54 PB0CEE DINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
Esthonia, where he spent the remainder of his life, much respected
hy all. On December 27th, 1887, the Geological Committee of the
Institute of Mines at St. Petersburg, with many other societies
and friends, celebrated the jubilee of his scientific work. On this
occasion a congratulatory letter was sent to him from the Council
of this Society.
Yon Keyserling died at Raykiill on the 8th May, 1891, in the
76th year of his age. For some reason this obituary notice has
been delayed.
Prof. Juan Vilanova t Pi era, Foreign Correspondent, was born
at Valencia in 1822. He was originally brought up to the medical
profession, obtaining his degree of licenoiate in 1845, but hardly ever
practised, as in early life he devoted himself to geological pursuits.
About the year 1853 the Spanish Government gave him a com-
mission to study geology in different European countries, and he
travelled accordingly for a considerable number of years. On his
return to Spain he was promoted to the Chair of Geology in the
Natural History Museum at Madrid, a post which he held till 1873,
vrhon he became the first occupant of the new Chair of Palaeontology.
About this period he also brought out a text-book of geology, for a
li>ng time the only one in the Spanish language.
As a member of the national Survey he studied the geology of
the provinces of Teruel, Castellon, and Valencia, and published
geological maps and memoirs relating to them. Of late years he
was much interested in prehistoric subjects, and besides his publi-
cations ho endeavoured to popularize this branch of study by
frequent lectures in Madrid and the provinces. Agriculture also, in
its relations to geological science, was one of his favourite themes.
Vilanova diod at Madrid on the 7th June, 1893, having just
completed his 71st year.
Kabl August Losses, Foreign Correspondent, Professor of Petro-
graphy and Geology in the University and Mining Academy, Berlin,
was born on the 5th January, 1841, at Kreuznach, in Khenish
Prussia, where his father was in the medical profession. After
leaving school young Lossen chose mining — a career which he after-
wards gave up in order to turn his attention to geology and more
especially petrography. In 1869, he took his degree in the philo-
sophical faculty of the University of Halle with his thesis 4 Dt Tauni
montis parte trantrhenand,' having also obtained much geological
experience under Beyrich in the Harz. In 1872, on his admission
to the Prussian Geological Survey, he was commissioned by the
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 55
Directors with the investigation of that district, and the admirable
map of the Harz, subsequently published by the Survey, was mainly
his work.
Lossen's researches in the Harz caused a new departure in petro-
graphy, and he is regarded as the founder of 4 dynamo-metu-
morphisra,' which treats of the effects of mechanical force on the
structure of rocks. He supplied evidence of differentiation in rock-
magmas, being particular in the determination of rocks according
to their structural and chemical characters with reference to their
mode of occurrence, whilst he studied the various results of the
consolidation of one and the same magma under various conditions.
He was not a voluminous writer, but his communications were
careful and elaborate. Most of his publications are to be found in
the * Jahrbuch der konigl. Preussischen geologischen Landesanstalt
und Bergakademie,' in the volumes of the German Geological
Society, and in the Proceedings of the 1 Gesellschaft der natur-
forschenden Freunde.' Though terribly afflicted with deafness,
which precluded him from general conversation, Prof. Lossen was
well able, through his exceptional command of language, to carry all
before him when a suitable occasion arose.
Ho died at Berlin, after a long and painful illness, on the 24th
February, 1893, at the ago of 52.
Dionts Stfr, Foreign Member, was born on April 5th, 1827,
at Beczko, in Upper Hungary, at which place his father was
schoolmaster. After completing his classical studies at the
Gymnasium ( = Grammar School) at Modern, and his course of
philosophy at the Protestant Collego at Pressburg, Stur attended
the mathematical and physical classes at the Vienna Polytech-
nikum, and subsequently the public lectures on mineralogy
and geognosy, which were delivered in the later 'forties at the
Imperial-Royal Museum of Mines by Hen-en von Haidingcr, von
Hauer, etc. He perfected his professional training at the Imperial-
Royal Mining Academy in Schemnitz.
Thoroughly prepared in this wise for the calling of a field-
geologist, and well endowed in body as in mind, Stur joined, in
April 1850, the then newly-established Imperial-Royal Geological
Survey, on the staff of which he served uninterruptedly for well-
nigh 43 years, during the last seven of which he was Director,
being further honoured with the title aud office of Councillor of the
Imperial-Royal Court.
For twenty-five years Stur took a very prominent share in the
c2
56 PBOCKEDIXGS OK THE GEOLOGICAL SOCIETY". [May 1 894,
field-work of the Imperial-Royal Geological Survey, and was busied
with geological surveys in almost every district of the Austro-
Hungarian monarchy. From that period dates a long series of
scientitic papers, mostly published in the Annuals (Jahrbiicher) of
the Survey, and many of these may be regarded as establishing the
bases of the geological exploration of the Empire.
In addition to his geological acquirements, Stur possessed ex-
cellent training in and good knowledge of botany ; and so we may
easily conceivo that, next to his geological field-work, paleobotany
should form his favourite study ; and later, when, owing to his
promotion to the post of Vice-Director, he had bidden farewell to
work in the field, he devoted himself entirely to the investigation
of fossil floras, in particular those of the Culm and Carboniferous
formations. An eloquent testimony of his unceasing activity in
this direction is afforded by the exhaustive papers on the * Culm
Flora' and the * Carboniferous Flora of the Schatzlar Beds/
published by him in tho Transactions ( Abhandlungen) of the
Imperial-Royal Geological Survey (vols. viii. & xi.).
When, in the year 1885, Fr. von Hauer was appointed Curator of
the Imperial-Royal Museum of Natural History, Stur succeeded
him in the Directorship of the Imperial-Royal Geological Survey,
and fulfilled with zeal and self-sacrificing devotion the duties of this
post for very nearly eight years, until a rapidly developing malady
of the heart compelled him to request his transfer to the retired
list. This request was granted on the 21st October, 1S92, together
with a flattering distinction in the shape of the Knight's Cross of
the Order of Leopold. But retirement did not bring tranquillity to
Stur, now become grievously ill, and death released him from his
sufferings on the 9th October, 1S93, in the 67th year of his age.
Pierbe J. Van Benedbn, Foreign Member, was born at Malines
on the 19th December, 1809, and received his early education there.
Subsequently he studied with a chemist, M. Stoffels, who strongly
imbued his pupil with a taste for zoology in addition to other
scientitic pursuits. In 1831 Van Benoden went to Louvain to
pass his examination in Natural Science, obtaining the title of
doctor after a year and a half at the University, during which
period ho continued to occupy himself with zoology, in virtue of
his office as Curator of the Univorsity collections, which he arranged
most thoroughly.
In order to complete his education Van Beneden spent the years
1834 and 1833 in Taris, where he established relations with those
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
5?
who cultivated zoological science, and about this period he travelled
in many parts of France and also in Italy for the purpose of gaining
experience, being especially interested in marine biology. On
returning to Belgium, after an appointment at Ghent which led
to nothing, he was installed Professor of Zoology and Comparative
Anatomy in the University of Louvain. This was in 1836, and
he held that post, as a teacher of science, without interruption, to
the day of his death, a period of 57 years. In 1865 he undertook
to teach palaeontology, and continued to give lectures in that branch
of science until the end of his life.
Essentially a zoologist, Van Beneden was an indefatigable worker,
including most branches of the animal kingdom within the range
of his studies. His Academic publicat ions, which were exceedingly
numerous, do not often deal with palreontological subjects; but
he would occasionally write on fossil Cetaceans from the Antwerp
basin, or on the tooth of a fossil seal from the Crag of that district,
sometimes extending his notices of fossil Cetaceans as far as
Croatia. Amongst his non-Academic work may be mentioned his
Report on the palaeontological collections of the University of
Louvain, published in 1867 ; a note on tho Bats of the Mammoth
period as compared with those of the present, in the British Asso-
ciation Reports for 1871 ; and on a new fossil bird from the caverns
of New Zealand. His most important paheontological work probably
was his description of the fossil bones of the neighbourhood of
Antwerp, with copious illustrations. This appeared in four parts
in the * Annals of the Royal Museum of Natural History of Brussels/
the first having been published in 1877 and the fourth in 1885.
In the following year was celebrated the jubilee of Van Beneden's
professorship under the honorary presidency of De la Valldo Poussin,
whose admirable address on the occasion did no more than justice
to the attainments and career of his illustrious colleague. In 1888
Van Beneden was elected a Foreign Member of this Society, being
at that time also an honorary LL.D. of the University of Edinburgh.
But the honours and acknowledgments which were bestowed so
freely on this veteran zoologist in no wise caused him to relax his
educational efforts, as we find him giving his latest lecture on the
20th December, 1893, or less than three weeks before his death,
which occurred at Louvain, on the 8th January last, at the age of 84.
58 PROCEEDINGS OP THE 0EOLOO1CAL SOCIETY. [May 1894,
ON SOME RECENT WORK OF THE GEOLOGICAL SOCIETY.
Past II.
Is continuation of the subject of the preceding Anniversary
Address it becomes my duty, on the present occasion, to attempt
some notice of a portion, at least, of the numerous papers con-
tributed within the septennial limits, which were left untouched
last year. These I would roughly divide into two groups.
In the fint group are placed papers relating to the Newer Palaeozoic
Rocks, the Older Palaeozoic Rocks, and the Fundamental Rocks,
which bear upon the geology of the British Isles or their immediate
vicinity. With these will be associated a large series of papers on
General Petrology, dealing chiefly with igneous and metamorphic
rocks, though I shall not attempt to touch upon matters which are,
in the main, petrographical.
In the second group are numerous papers which may be roughly clas-
sified under the following headings : Miscellaneous Geology, Foreign
and Colonial; Miscellaneous Invertebrate Palaeontology ; Paleobotany;
and lastly Dynamical Problems. This group of subjects is so varied
and so large that it would be impossible, within the limits of an
address, to deal with it in anything like a comprehensive manner.
Nevertheless, many of the papers are of great value ; as, for instance,
* The Contribution to the Geology and Physical Geography of the
Cape Colony,' by Prof. Green ; 1 The Geology of the Wengen and
St. Cassian Strata/ by Miss Ogilvie ; 4 The Leaf-beds and Gravels
of Ardtun in Mull/ by Mr. Starkie Gardner ; not to mention others
of equal interest. Before proceeding, therefore, to a more detailed
consideration of the first group of papers, I submit a kind of synopsis
of the second group under the headings above indicated.
Miscellaneous Geology, Foreign and Colonial. — This is of course a
somewhat exhaustive division, comprising about a score of papers,
which deal with many subjects in different parts of the world.
Thus, we have had several communications respecting Africa. Indeed
it is scarcely too much to say that the outlines of the geology of the
■ Dark Continent 9 are by degrees being made known ; and we may
hope that, when Mr. Gregory has time to tell us the story of Mount
Kenia, the Geological Society will be in possession of further details
respecting a region which is now attracting so much attention.
I have already alluded to Prof. Green's paper, where he gives a
Vol. 50.] AKKIYERSART ADDRESS OF THE PRESIDENT. 59
summary of his views as to the probable geological history of Sooth
Africa, concluding that, since the great uplift of the country took
place, that region has probably continued dry land to the present
day, " for the scrape of Jurassic, Cretaceous, and Tertiary formations
that it possesses lie close to the coast and were apparently formed
at no great distance from the shore."
These words bring us to the consideration of Mr. Baron's paper
on Madagascar, where the author tells us that sedimentary rocks
occur mainly on the western and southern sides of the island. The
relation of these to each other has not yet been determined ; but
judging from the fossils it would seem that the following formations
are represented, viz. : — Lias, Lower Oolites, Oxfordian, Neocomian,
Upper Cretaceous, and Eocene, whilst Recent Deposits fringe the
coast and are largely developed on the southern part of the island.
That portion of Madagascar which faces the Indian Ocean is
represented as consisting of crystalline rocks with some volcanic
ones. Hence, all the Neozoic beds above detailed must have been
deposited within the area of the Mozambique Channel; nor do
the eastern shores of the island furnish us with any evidence of
what kind of rocks the fabled Lemuria consisted.
Beverting once more to South Africa, I may remind you that
Mr. Penning, in a * Contribution to the Geology of the Southern
Transvaal/ directed attention more especially to the relation of the
Gold-fields to eaoh other, and to the high-level Coal-field of that
region. He at the same time submitted a classification of the
sedimentary rocks, dividing the high-level Coal-field into the Kim-
berley Beds and the High Veldt Beds, both of which he conceived
to be of Oolitic age : upon this point it must be admitted there
is considerable difference of opinion. The Witwatersrandt Series
and associated beds he considered to be of Devonian ago. More-
over, he expressed his opinion that the region had been under
glacial influences during the long period which intervened between
their deposition and that of the coal-bearing rocks of the High
Veldt. These latter he considers to be of fluviatile origin, and he
concludes that there has been a continuity of eubaerial denudation
from the close of the Oolitic period until the present time.
Some of the details of this paper were criticized, especially by
Mr. Walcot Gibson and Mr. Alford. The former of these gentle-
men subsequently communicated a paper on the ' Geology of the
Gold-bearing Districts of the Southern Transvaal,' wherein he
concludes that the gold-bearing conglomerates of the Witwaters-
Digitized by Google
6o
PROCEEDINGS OF THE GEOLOGICAL SOCIETY,
[May 1894,
randt district, with their associated quartz and shales, form one
series, which has undergone a considerable amount of metamorph-
ism. This series is much newer than the crystalline rocks on
which it rests, since the gold-bearing conglomerates hare been
formed mainly at the expense of the underlying granites and
gneisses, which are largely threaded with auriferous quartz-veins.
As regards stratigraphical arrangement, the entire series associated
with these gold-bearing beds has been thrust over the gneisses.
Consequently, the beds do not seem to be contained in a simple
basin ; but, as was pointed out by Prof. Lapworth, it is probable
there has been overthrusting and shearing along the edges of the
basin, and possibly repetition in its interior, so that the actual
thickness of the beds may not be very great. Mr. Gibson observes
that subsequent to these movements the strata were injected
with basic igneous material, and much of the country was flooded
with lavas of a similar character.
Mr. Attwood, who has had considerable experience in gold-fields
and their surroundings, stated that this district bore no resemblance,
geologically Bpeaking, to anything hitherto discovered and was
therefore of special interest. He did not think that the gold in
the quartzites and conglomerates could be called alluvial gold, as
suggested by Prof. Green, because the metal is reported to be found
in a fine state of division, whilst in all true alluvial deposits it
is found of various forms and sizes. On tho whole, Mr. Waleofc
Gibson was somewhat reticent as to the origin and method
of deposit of the gold, but Mr. Alford stated his opinions on these
points rather more freely, whilst allowing that the subject was
an intricate one. The gold, he said, occurred in the matrix of the
conglomerate and seldom in the quartz- pebbles, and, although the
conglomerate-reefs were by no means regular in gold-bearing
value, that value appeared to be greater where the beds had a high
angle of dip and were in proximity te intrusive igneous rocks.
Por a further expression of Mr. Alford's views on this curious forma-"
tion reference may be made to a work of his which has been lately
published.1 As it is admitted on all sides that the Witwaters-
randt Series is one of exceptional character, I may be pardoned for
having dwelt upon the subject at some length.
African geology has been further enriched by an interesting
communication from Prof. Valentine Ball * On some eroded Agate-
pebbles from the 8oudan,' which were collected by Surgeon-Major
* 'Geological Features of the Transvaal,' London: Stanford, 18»1.
Digitized by Google
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
Greene. To the British occupation of Egypt we likewise owe some
* Notes on the Geology of the Northern Etbai or Eastern Desert of
Egypt, with an account of the Emerald Mines/ by Mr. Ernest
Fioyer. This gentleman enjoyed exceptional advantages in the
examination of a highly interesting district, which is difficult of
access tinder ordinary circumstances. His conclusions as to the
relations of the crystalline to the sedimentary series are somewhat
at variance with those of the majority of previous authors, who
have described adjacent districts in Egypt aud the Sinaitic peninsula.
As regards the matrix of the emerald in these ancient and now
abandoned mines, we have tho authority of Mr. Rudler that it
appears to be a biotitc-schist, more or less talcose, the mode of
occurrence being somewhat similar to that of tho emeralds of
Siberia, where the mineral is associated with mica-schist. In
' Notes from the Nile Valley,' by Messrs. Johnson and Richmond,
the information concerning the region south of Assouan is of con-
siderable interest, though the intrusion of the granite into the
sandstone, like a similar statement by Mr. Fioyer, opens up new
views as to the geology of these regions. In reference to this and
other questions, we have tho conclusions of Prof. Hull on the
geological features of Arabia Petnca and Palestine, an outline of
which was lately offered to the Society.
Under the heading ' Miscellaneous Geology 'I would further draw
attention to several interesting papers on Metalliferous Deposits —
such as a paper by Mr. Attwood on the Auriferous Tracts of Mysore,
a paper by the late Mr. Becher on the Gold-quartz Deposits of
Pahang, one by Mr. Power on the Pambula Gold Deposits, and two
papers by Mr. Collins on the Sudbury Copper Deposits and on the
Geology of the Bridgwater District — both localities in Canada.
Furthermore, there is a paper by Messrs. Hughes and Bonney on
the Obermittweida Conglomerate, one by Mr. Lister on the Geology
of the Tonga Islands, and one by Prof. Hull on the Physical Geology
of Tennessee Mr. Cooke tells us about the Marls and Clays of the
M altese Islands, Lieut. Frederick writes of certain islands in the New
Hebrides, and finally there is the admirable papor, to which I have
already alluded, by Miss Ogilvie on the Geology of the Wengen
and St. Cassian Strata.
Miscellaneous Invertebrate Pdkeontology. — There are a score of
papers which may be thus classified, dealing with siliceous organisms,
with corals, crinoidea, bryozoa, ostracoda, and cephalopoda.
62 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
Messrs. Duncan, Hinde, Bather, Gregory, Shannan, Newton,
Waters, Rupert Jones, Shrubsole, and Buckman have all been con-
tributors to this branch of science. Most of these matters are for
the consideration of specialists, and would come more directly under
the cognizance of a President who was himself a general palaeonto-
logist. I venture, however, to draw your attention to the valuable
work of Prof. Rupert Jones amongst the Entomostraca. He has
described and illustrated in two papers Palaeozoic ostracoda from
North America, Wales, Ireland, France, and the Bosphorus, showing
in particular the wide distribution of some of the species. Two
more well-illustrated papers have been devoted to Palaeozoic ostra-
coda from Westmoreland and the Girvan district, and on this
occasion the Senior Secretary expressed his obligations for the
trouble which the Author had taken in studying these obscure fossils
from the Cross Fell inlier. During the present session, as you will
remember, Prof. Rupert Jones assisted Messrs. Andrews and Jukes-
Browne in determining certain ostracoda from the Vale of Wardour
with results which might almost be deemed revolutionary. We
hope, also, to see his latest contribution 4 On the Rhsetic and some
Liassic Ostracoda of Britain ' published in the May number of the
Quarterly Journal.
•
Paleobotany. — Although there are a few short notices by other
authors, the only contribution of any magnitude under this heading
is one by Mr. Starkie Gardner * On the Leaf-beds and Gravels of
Ardtun in Mull/ with notes by Mr. Cole. This paper is, in the main,
a redescription of the beds which were discovered by the Duke of
Argyll about 43 years ago, and of their contents. One of the
Author's objects was to prove that instead of belonging to the
Miocene these floras are of Eocene age, and in fact older than the
Thanet Beds. Summarizing their contents, it appears that only
two vascular cryptogams are known, whilst among the gymno-
sperms Ginkgo is exceedingly abundant, associated with Podocarpu*
and Taxua. There are no monocotyledons beyond a liliaceous-
looking leaf and a few reed-like stems. The dicotyledons are
abundant, the collections being said to include more than 30 dis-
tinct species, most of them so adequately represented that the range
of variation in the leaf is practically ascertained. Some remarkably
well-preserved specimens from the Limestone of Ardtun are figured
in the accompanying plates, which were executed by Mr. Gardner
himself.
Digitized by Google
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
It remains for the students of fossil botany to determine how far
this analysis, which was extended to the plant-bed at Atanekerdluk
in Greenland, can be substantiated. Meanwhile, the Author con-
tended that the identification of the above flora with the Miocene
plants of Europe was groundless, or only applicable to such pre-
vailing types of leaves as are common to widely distinct genera, and
which occur in floras recent as well as fossil. He held that the
resemblance and even identity of the best characterized forms with
the older Eocene plants had been ignored. The most strongly
marked types of Greenland, which also recur in Antrim, are met
with in the Heersian of Gelinden and on no other horizon. These
amply suffice to fix the date of the Antrim flora, whilst that of
Mull is regarded as somewhat older. Independently of positive
evidence, the absence of any late Tertiary types, even of the Legu-
minosffi which abound as low down as the Heading Beds, is held by
Mr. Gardner to indicate their antiquity.
Dynamical Problems. — There have been two papers by Mr. Charles
Davison * On the Movement of Scree Material,' one by Mr. Oldham
4 On the Law that Limits the Action of Flowing Streams/ one by
Mr. Barlow 4 On the Horizontal Movements of Rocks,' and possibly
some other papers which might come under this heading, such as
Mr Davison's notice of the Inverness Earthquake. A valuable
communication from Prof. Spencer 4 On the Origin of the Basins of
the Great Lakes of America ' would seem also to find a place here.
It is now time to call your attention to the four principal subjects
constituting the first group— which I propose to consider somewhat
in detail. These are The Newer Palctozoic Rocks, The Older Pahxo-
zoic Rocks, The Fundamental Rock*, and General Petrology,
The Newbb Palaeozoic Bocks.
Coal-measures, — The Carboniferous System has not yielded ns
any important stratigraphical papers of late years ; consequently
such matters as have been brought to the notice of the Society
relate to details of varied character.
Thus, for instance, the question of boulders found in scams of
coal has been raised by two Authors, viz. Mr. James Ratcliffe and
3Xr. John Spencer. The former indicated a series of boulders,
rafcnging from 4 to 166 lbs. in weight, which hod been embedded in
tlm^e roof of a coal-seam in the Manchester district, similar boulders
64 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
having been described from other English coal-fields. Those noted
by Mr. Ratcliffe were principally of quartzite, but boulders of
granite have also been found. The principal facts to notice are,
that the rocks are foreign to the district, that the boulders are
isolated, and occasionally even striated (?), and that they seem to be
waterworn and rounded. Sometimes they occur in the bed of coal,
but more frequently at its junction with the overlying rock. Some
importance attaches to these boulders, both on account of the general
rarity of pebbles throughout the Coal-measures and also because of
the speculations as to the possible transporting agent.
It is certainly a curious fact that, if a few hundredweights of
rock are found in an isolated position in any of the sedimentary
series, the action of ice is sure to be invoked to account for the pheno-
menon. This, for instance, is what Mr. Spencer did in his short
notice * On Boulders found in Seams of Coal/ though we may well
believe that transport by the roots of trees or floating vegetation of
some sort is an equally good, if not, indeed, a more probable expla-
nation. It has been suggested that, in the case mentioned by
Mr. Katcliffe, the boulders may have come from some of the pre-
Carboniferous conglomerates of the North of England or of Scotland.
As the boulders have all the appearance of having been dropped
quietly upon the top of the coal, this would imply some depth of
water overhead, whatever may have been the agent of transportation.
In the Carboniferous Limestone of the neighbourhood of Dublin,
Prof. Ball has lately pointed out that angular fragment* of granite
and other hard rocks have been found. Whilst rejecting the view
that they had been transported by ice, he maintained that they need
not necessarily have been carried by land plants, but that they
might have been torn from the sea-floor by marine algae. He cited
the case of a saudy beach at Youghal, where the shore is strewn
with limestone-fragments which had been conveyed by seaweeds
thrown up after storms from submarine banks. Attention was also
drawn to Anson's mention of the occurrence of sea weeds loaded with
stones far out at sea.
Some interesting facts in connexion with coal-seams were
recorded by Mr. Hendy in his short paper on a ' wash-out ' in one
of the Derbyshire collieries, the nature of the phenomena being
aptly illustrated by a series of sections drawn to scale. It has fre-
quently been suggested that such 1 wash-oats ' are due to faulting,
but in this instance, at least, such can hardly have been the case,
since the underclay and underlying sandstone are undisturbed,
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. 65
although in one instance tho underclay is seen to have been cut
through by the denuding agent. The space of the 4 wash-out ' is
filled up by sandstone. This is clearly an instance of contempora-
neous erosion, and the 4 wash-out 1 may actually represent one of
the river-beds of the fen in which the coal accumulated. In this
case one third to one half of the coal is said to have been re-deposited
in different places on the sides, the remainder having evidently been
carried away, thus pointing to a kind of intermittent action of the
water.
In a paper on tho Formation of Coal-seams, Mr. Gresley, from
evidence gathered chiefly in the Leicestershire and South Derbyshire
coal-fields, is disposed to contest the orthodox view of growth in
situ. Without myself venturing to express an opinion upon this
point, it seems to me that the experience of mining engineers and
others connected with the working of coal is of great importance.
It sometimes happens that professional men of this sort, though
possessed of valuable information, are unable to put it into a
geological form, and require, as it were, an interpreter. But such is
not Mr. Gresley's case, and I venture to think that an abstract of
his arguments is worthy of attention.
In considering the relations of the fire-clays to the coal-seams,
he points out that such fire-clays, containing Stigmaria and root-
like fossils, occur in other positions than that of an underclay to
coal; that the thickness of an underclay bears no proportion to
that of the coal-seam resting upon it ; and that the underclay is
usually divided off from the coal-seam by a true bedding-plane,
nor is there any merging of one formation into the other. Secondly,
when considering the behaviour of Stigmaria-Toots, he points out
that a considerable proportion of the underclays do not contain
Stigmaria-ioots at all, though they seldom fail to reveal the
presence of thin, grass-like, fossil markings. But when Stigmarim
do occur in the underclays, they do not, as a rule, pass upwards
into the coal. Moreover, when erect fossil stems or stools of trees
are met with, they arc generally either resting upon or at no great
distance from the tops of coal-beds ; though the best examples, such
as the fossil trees at Clayton and Bradford, have occurred in beds far
removed from coal. He concludes that the general absence of erect
fossil tree-stems in underclays is an argument against a growth in
gitu of coal, at all events from trees. Thirdly, in considering the
question of lamination, he asserts that the laminated character of
coal affords no evidence that the coal- forming plants grew upon the
Digitized by Google
66 PROCEEDINGS OF THE SEOLOGICiX SOCIETY. [May 1 894,
spot. If there had been any great number of upright trees they would
have interfered with the parallel structure of the coal, nor is it
probable that this interference would have been obliterated by
pressure or by metamorphism. Where are the trees from which the
macrospores of spore-coal were shed ? The partings of coal in seams
have yet, he thinks, to be explained.
Some other considerations were advanced by Mr. Gresley of
a more general nature, such as the presence of boulders and other
foreign bodies in the undnrclay and coal-beds ; whilst aquatic
mollusca and fishes are found in the coal itself. He points out
likewise that marine conditions prevailed, if not during the accu-
mulation of many of our coal-beds, vet without doubt immediately
afterwards, as may be inferred from the presence of marine fossils
and brine in the coal.
Let us now turn to a paper by Mr. Kirkby on the occurrence of
marine fossils in the Coal-measures of Fife. These are divided into
two series, viz. the Lower Beds with workable coals (t/6 of the
Geol. Survey) and the Upper Red Beds (dy of the Geol. Survey).
The mariixe bed lios almost at the top of the former series, having
been proved at two localities. Together with the remains of some
of the ordinary Coal-measure fishes there occur, in a dark-coloured
shale, specimens of Disci tes and Ortliocera*, of BtUerophon and
Murchisonut) and of Productus, Disci tiay and Lingula. One of these
latter, viz. Lingula mytiloides^ is also found along with Discina
nitida in the Lower Permian limestone of Durham and Northumber-
land.
This author likewise proceeds to enumerate the occurrence of
marine fossils in the Coal-measures cf the West of Scotland, where
they have been noted on no less than four horizons. He further
illustrates his views by quoting Phillips's notice of the occurrence
of Aviculoptcten, Fosidonomya, Goniatite*, and Orthoceras in the
roof of one of the Ganister Coals in the West Riding of Yorkshire,
and alludes to the occurrence of brine both in the Lancashire and
Staffordshire coal-fields.
In speculating on the conclusions which may be adduced from the
above facts, Mr. Kirkby speaks of inroads of the sea bringing back
species of shells and even crinoids, such as had existed in the
Carboniferous Limcstono ocean of an earlier period, and thus infers
that the sea itself could not have been far off during the deposition
of the Coal-measures. These intercalated marine beds, he save,
6cem easier of explanation when the formation is looked upon
Digitized by Google
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
67
as deltaic ; tinder such conditions everything observed in the
palaeontology of the strata can be accounted for, whether the
indications be of dense vegetable growth or of vegetable drift,
and also whether the animal life presents a freshwater, brackish-
water, or marine f octet. On the whole, he strongly questions the
merely lacustrine origin of the Coal-measures.
On these points, again, we have the very recent testimony of
Dr. Wheelton Hind, whose paper, though mainly palseontological,
is eminently suggestive. In writing of the affinities of Anthraco-
ptera 1 and Anthracomya this author concludes to place the former
genus in the family Mytilidte, whilst Anthracomya is classed with
the Unionidce. The paleeontological details are fully worked out,
and present points of considerable interest There is no evidence
that the shells of Anthracomya represent burrowing species, since
they are never found lying at right angles to the lines of stratification.
The shells approximate closely to Anodon, but they lack the
eroded obsolete beaks, the supplementary anterior-adductor muscle-
scar, and the equal valves of this form.
Salter, he observes, believed that the beds in which Anthracosia,
Anthracoptera, and Anthracomya occur were of marine or of highly
brackish-water origin. Doubtless, remarks Dr. Wheelton Hind,
there are truly marine beds in the Coal-measures, and these
contain a characteristic marine fauna, yielding Productus, Spirifcr,
Lingula, Discina, AviculojMCten, Potidonia, Edmondia, Sanguinolitet,
Orthoceras, Ooniatites, and Nautilus, not only towards the base as
in the Ganister beds, but also much higher up in the series as
developed in North Staffordshire. In none of such beds do
Anthracosia, Anthracoptera, and Anthracomya occur; but, on the
other hand, these genera are found associated with a peculiar fauna
of fishes and reptiles, annelids and crustaceans, which have a close
affinity with recent forms inhabiting fresh water, together with a
flora of ferns, Sigillaria, Catamites, and Lepidodendron. The fact
of typical marine fossils being found in a few beds of small extent,
intercalated in the coal strata, seems to Dr. Hind to afford strong
evidence that the rest of the beds were not marine. The general
affinities of Anthracoptera and Anthracomya with recent freshwater
shells afford strong presumptive evidence of the freshwater origin of
the greater part of the Coal-measures, nor has any mixture of
fluviatile and marine forms in the same bed come to his knowledge.
1 It seems probable that Salter's genus Anthracoptera will here to give wny
to A'aiadifes, Dawson.
68 PROCEEDINGS OF THE QEOLOGICAL SOCIETY". [May 1 894,
If wo endeavour to draw any practical conclusions from the
above-quoted papers as to the mode of formation of coal-seams, and
also as regards the origin of the Coal-measures generally, we can
scarcely do better, in the first instance, than accept the suggestion
of Mr. Kirkby that the Coal-measures both in Scotland and the
North of England represent, in the main, deltaic formations rather
than lacustrine ones. There is but little novelty in the recognition
of marine fossils in the Coal-measures, but the facta required to be
brought forward more prominently, and especially to be sifted
as they have been by Dr. Wheelton Hind. When we read of
incursions of the sea we are reminded of what occurs from time to
time in all deltaic or estuarine deposits ; and these facts may to a
certain extent be paralleled in the Jurassic coal-field of Yorkshire,
and even in the Purbecks, though in the latter case without coal.
Of course, in such areas there would be plenty of freshwater lagoons
or lakelets, with their peculiar fauna ; and Mr. Oresley need not be
surprised at fish-remains occurring in coal, even on the supposition
that a large portion of it representa local growths. The fens which
border the Wash consist very largely of peat formed from local
growth, and shallow basins in this peat, such as Whittlesea Mere,
used to be full of fish. There must be many a pike buried in the
peat of that now-drained fen ready to be converted into a « fossil
fish in coaT under the requisite conditions. Again, it is not
unlikely that the old Carboniferous fens were occasionally per-
meated by channels, which would in times of flood have connexion
with a bigger river. This view might help to explain the flotation
of Bpore-cases, and even the transport of boulders from afar, which,
having journeyed for some distance on floating vegetation, were
quietly dropped from the surface of some calm and shallow pool
upon the peat beneath. In conclusion, we may feel sure that just
as the nature of coal varies so did the methods by which it was
produced.
Coal in the South-east of England.
Just about seven years ago Mr. Whitaker contributed some
further notes on the results of deep borings in Kent. This supple-
mentary paper was brought before the Society owing to the fresh
light which a boring at Dover at that time seemed to throw on the
underground geology of the London Basin. The boring in question
was made at the convict prison, and, having been abandoned at
931 feet from the surface, failed to reach the Palaeozoic rocks.
Digitized by Google
Vol. 50.J
ANMVKRSARY ADDBB88 OF THE PRKS1DL.NT
69
Mr. Whitaker, however, concluded his paper with some valuable
remarks on the best site for additional borings at Dover in the hope
of piercing the Coal-measures. Ho mentioned with especial satis-
faction the accounts of the trial-boring then being made at the foot
of Shakespeare's Cliff, being even then animated by the conviction
that the day would come when coal would be worked in the South-
east of England.
Since this paper was read no further communication has been
made to the Society with reference to boring at Dover, though you
are well aware that considerable progress has been made in this
direction through tho exertions of Mr. Francis Brady, Chief Resident
Engineer of the South Eastern Railway, and his able coadjutors.
That gentleman, in June 1892, published an interesting report of
the Dover Coal-boring,1 at which date the depth attained was about
1875 feet. In December of the same year he had the satisfaction of
being able to forward a telegram to Sir Edward Watkin to the
effect that a 4-foot seam of good bituminous coal had been proved
at a depth of 2180 feet (the telegram says 2222 feet). As this
report deals with a question which had already been raised by
Mr. Whitaker in the Quarterly Journal, we are justified in con-
sidering the evidence which it affords of tho development of the
Coal-measures in the South-east of England.
To the Report is appended a vertical section giving full par-
ticulars as known up to December 1892, since which date, I am
given to understand, no greater depths have been proved. The
boring, it will be remembered, starts in the Grey Chalk, and
passes through 250 feet moro of Upper Cretaceous rocks, inclusive
of the Gault. The Lower Cretaceous rocks, including the Lower
Greensand, tho Wealden and Hastings Beds, are estimated at no
more than 241 feet, whilst tho Jurassic rocks, including Upper.
Middle, and Lower Oolites, with Lias at the base, are held to account
for 613 feet. The total thickness of Mesozoic rocks, or 4 dead beds/
bored through is 1113 feet, at which point the Coal-measures arc
struck.
As we are not dealing with tho Mesozoic rocks on tho present
occasion, the above estimates may pass without criticism, our atten-
tion being fixed on the details of tho 1068 feet of Coal-measure*
revealed by the boring-rod. In this series there arc about 12
seams of coal, ranging from 1 to 4 feet in thickness, and terminating
• * Dover Coal-boring. — Observations on the Correlation of tho Franco-
Belgian, Dorer, and Somerset Coal-fields.' (?) London, 1892.
VOL. L. /
70
PROCEEDINGS OP THE GEOLOGICAL 80CIETT. [May I 894,
in the 4 feet of good bituminous coal, which has so raised the ex-
pectations of the explorers. The beds are believed to be nearly
horizontal, and, as they contain 1 foot of coal to about 50 feet of
measures, they compare favourably with those in the Radstock field,
where the proportion is 1 foot of coal to about 80 feet of measures.
The seams proved are stated generally to have the same quality as
the rich bituminous coals of Mons and Bruay, and do not resemble
the dry coal of Marquise, which is supposed to be of earlier
date. Messrs. Zeiller and Breton, having studied the fossil plants
found in these Dover Coal-measures, are of opinion that the Dover
coal belongs to the upper portion of the Nord and Pas-de-Calais
coal-basins. Mr. Brady maintains, therefore, that not only is the
quality of the Dover coal likely to be found equal to some of the
best Belgian coals, but that the beds of the Pas-de-Calais increase
in thickness to the westward, both conclusions being contrary to
the views maintained before the Coal Commission in 1869.
A shaft is now being sunk, but this, according to Mr. Etheridge,
has not yet progressed beyond the Cretaceous beds ; hence no
further information rolative to the Coal-measures has, so far as
I know, been forthcoming from this quarter. We are, however,
naturally led to speculate on the general question of coal in the
South-east of England from the facts recently ascertained. Prof.
Prestwich, it will be remembered, in his Report of 1871 to the
Coal Commission, in the first place spoke of the original coal-trough
as having been broken up into separate basins ; and, secondly, in
forecasting the probable direction of the underground (sub-Mesozoic)
axis, he suggested two alternatives, roughly north or south of the
Thames. Each view probably has its respective advocates. The
Eastern counties have formed a * Coal-boring and Development
Association,' and although the prospects of finding coal in the East
Anglian Palaeozoic area are not very bright, it is just possible that
the adventurers may strike the Coal-measures in one or other of
the narrow synclinal troughs running east and west in Essex,
Suffolk, and Norfolk. For my own part I am disposed to agree
with Mr. Brady that, in further explorations for coal beneath the
Secondary rocks, the southern alternative of Prestwich is the one
which holds out the greatest hopes. It will be tolerably safe to
assumo that future operations should follow a nearly direct westerly
course from Dover towards Bristol. These conclusions are mainly in
accord with those lately expressed by Prof. Boyd Dawkins 1 at the
1 Friday evening lecture at the Royal Institution, June 1890. ' Nature,'
toI. xlii. p. 319.
Digitized by Google
Tol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 7 1
Royal Institution, where he commented on the accaracy of Godwin-
Austen's views as to the range of the Coal-measures along the line
of the North Downs. It might not, perhaps, ho an unmixed ad-
vantage to bring more coal to London than finds its way there
already ; but if something in the nature of a coal-basin exists
within hail of the metropolis, it is quite as likely to be found
between Croydon and Reigate as anywhere else. If the Board of
Trade could be persuaded to bore at suitable intervals along a line
connecting those two towns, geological science would certainly be
a gainer, and Surrey as well as Kent might be proved to have its
coal-field.
Carboniferous Limestone. — There are no stratigraphical papers
dealing with this formation, but we have a series of palaeontologies!
papers by Miss Donald ; whilst Mr. Wethored gives us the results
of the examination of tho insoluble residues obtained from the
Carboniferous Limestone of Clifton.
In her first paper Miss Donald discusses the genetic relations of
the shells hitherto grouped under Murchisonia, more especially in
connexion with the sinuated genus Pleurotomaria, and the pos-
sibly, in somo cases, sinuated Turritella. The second paper is mainly
occupied in discussing some of the genera or sections into which
Murchisonia has been broken up, with more especial reference to
Ooniostropha. In the third paper the Author goes a step further
by founding the section Hypergonia, to include such forms as Mur-
ehisonia qwulricarinata, and other well-known species, where the
sinus is situated above tho angle. In this paper she likewise notes
the sections Ctdocaulus and Cerithioides, giving a full description
with figures of Cerithioides telescqrium, a fossil so named by
Haughton under the impression that it was a Pyramidellid, closely
related to the recent Cerithium telescopium. Miss Donald proposes
to retain the name Cerithioides for a section of Murchisonia, in
which this species might bo placed until more is known of its
affinities.
Beyond the fact that it relates to the Carboniferous Limestone,
Mr. Wethercd's papor covers entirely different ground. Incidentally
the Author classifies the series at Clifton, which has a thickness
of 2700 feet, for purposes of reference, but it is the microscopic
examination of the insoluble residues and of rock-sections to which
I must direct attention. Rocks with from 1 to 80 per cent, of
matter insoluble in hydrochloric acid were examined, the impurities
consisting mainly of detrital quartz, with here and there a few
f'2
Digitized by Google
72 PROCEEDINGS OF THE 6E0L06ICAL BOCIETT. [May l894r
grains of felspar, tourmaline, and zircon. In the main mass of
the calcareous rock there is, of course, a less amount of detrital
quartz, but the presence of micro-crystals of quartz, as also of
amorphous and chalcedonic silica and of sponge-spicules, was in-
dicated. The nature of the amorphous and chalcedonic silica in
the limestone, and the relations of this silica to the small quartz-
crystals, were also discussed. The latter were shown in Borne in-
stances to possess nuclei of detrital quartz, and, where this is not
the case, to have resulted from the crystallization of amorphous
silica. The chief interest in this portion of the paper, as was-
remarked at the time, lay in tho indications of a gradual passage
from amorphous silica into chalcedony, and so into quartz, it being
further observed that silica, in the rooks, has a tendency to pass-
towards the stable condition of that mineral
Devonian. — In direct continuation of the last subject, I have to
refer to another suggestive paper by Mr. Wethered on tho Devonian
Limestones of South Devon. In drawing conclusions from the
examination of the insoluble residues of examples collected in the
neighbourhood of Torquay and elsewhere, he observes that, whilst
well-rounded grains of detrital quartz were found in the Carboni-
ferous Limestone of Clifton, no such detrital grains can be discovered
in tho Devonian Limestone residues examined by him. Further, in
discussing the occurrence of micro- crystals of quartz he refers to
an observation by Prof. Sollas that such cnstals are left on dis-
solving Devonian Limestone, containing the so-called Strotnatopora
concentrica, from Kingstoignton. Yet Mr. Wethered doubts the
orgauic (spongc-spicule) oiigin of these micro-crystals of quartz in
the Dovonian Limestones, since he has not met with any siliceous
organisms, nor noticed ony such piocess as that described in his
previous paper. He is inclined to believe that these micro-crystals
of quartz have originated from the silica of decomposing silicates,
and, as a case in point, he notes that tho crystals of quartz are the
most numerous in those limestones which have undergone the
greatest amount of alteration through crystallization.
Mr. Wethered allows that the conclusions drawn from the micro-
scopic examination of the Devonian Limestones are not very satis-
factory, so far as structure is concerned. Yet ho has obtained
ample evidence that these limestones have been built up by the
remains of calcareous organisms, though the outlines of structure
have, for the most part, been obliterated by molecular changes. It
Digitized by Google
Vol. 50.J
AN VI VERS ART ADDRESS OF THE PRESIDENT.
73
is well known, he observes, that in more recent limestones the
interstices of the constituent organisms are generally occupied by a
quantity of calcite. In this case the original calcite of the lime-
stone can easily be recognized by its large clear crystals ; whilst,
on the other hand, the altered portion of the limestone is repre-
sented by small crystals in aggregates, and these are usually stained
by iron oxides. So far, he says, as the evidence warrants a con-
elusion being drawn, the Devonian Limestones of South Devon
appear to have chiefly originated from corals, crinoids, ostracoda,
stromatoporoids, and fragments of shell ; some limestones even
representing coral-reofs, others coralline debris ; the Goniatite
Limestone alone contains foraminifera. There is little, perhaps, in
this which has not previously been indicated by macroscopic evi-
dence, but it is satisfactory to find that evidence confirmed by the
microscope.
In discussing the more distinctly mineralogical questions, the
Author alludes to the occasional occurrence of rhombohedra of dolo-
mite. The micas, he thinks, may be of detrital origin, but this is
by no means certain. Minute crystals, referred to as 4 microlithic
needles/ resemble 4 clay-slate needles,' but are not always straight;
they occur in every fine residue, and as inclusions in siliceous and
micaceous flakes. The siliceous fragments which enclose them
frequently contain many liquid inclusions. These points were well
illustrated, and the investigations generally were regarded as of great
value in illustrating the history of mineral growth and develop-
ment. Dr. Sorby, who was present at the discussion, referred to
the fact that he had himself been led to study the Devonian Lime-
stones of Devonshire chiefly on account of the valuable evidence
they afford in connexion with the cause of slaty cleavage. He
thought that, taken as a whole, no group of limestones presents a
greater range of character ; for not only must their original nature
have varied extremely, but the amount of change due to chemical
reactions and to pressure had, in many cases, been considerable.
The South Devon rocks have, in addition to this paper by
Mr. Wethered, formed the subject of two extremely interesting
communications to the Society. In the first place, there was the
late Mr. Champernowno's notice of the Ashprington volcanic series
on the banks of the Dart below Totnes. This was a posthumous
paper, which we owe, in a great measure, to the care and solicitude
of Sir Archibald Geikie, and as he has dealt with the subject
fully in one of his Presidential Addresses, there is no need on the
Digitized by Google
74 PEOCBRDIN08 OF THE GEOLOGICAL SOCIETY. [May 1894,
present occasion to go into farther details. Mr. TJssher, who is the
author of the other paper referred to on the Devonian rocks of
South Devon, in alluding to Mr. Champernowne's work, writes as
follows : — " The existence of contemporaneous volcanic action — the
definition of the Ashprington series and of sporadic evidences of
local vulcanicity outside its borders — the correlation of the Ashburton
limestone with that of Newton and Ipplepen, — and palaeontologies!
contributions, adding to our knowledge of the Middle and Lower
Devonian, stand prominently forth amongst the labours of my de-
ceased friend So the present communication must be taken
as the outcome of my friend's life-work in Devonian geology, and
will, I trust, form not an unfitting tribute to his memory."
There can be no doubt that it has required in the past, and will yet
require in (he future, an immense amount of detailed observation
to put together the pieces of that geological puzzle which exists in
tho region between Dartmoor and the English Channel. As re-
marked by the Director-General of tho Geological Survey, dip and
strike go for littlo in such plicated and dislocated countries. Indeed,
we may say that without a palaeontologies! key the history of the
region could never have been deciphered. Unfortunately, in North
Devon, where the stratigraphy of the Devonian rocks is less com-
plicated, the differences of development are so considerable, more
especially in the rarity of calcareous beds resulting from coral-reefs,
and in the almost complete absence of contemporaneous volcanic rocks,
that the requisite information can hardly be obtained. It is in less
disturbed regions on the Continent, where the original development
is similar to that of South Devon, that we must seek for comparisons,
as Mr. Champernowne was in the habit of doing. Since his day an
important event has occurred ; I refer to the autumn excursion of
a party of the International Geological Congress of London, including
Messrs. Gosselet, Kayser, and others, conducted by Mr. Ussher.
Dr. Kayser embodied the results of his observations in a pamphlet,1 to
which I drew attention in my address to the Devonshire Association
in July, 1889.a The following is an extract : — " Herr Kayser finds in
South Devon a development which intimately approaches the West
German. In the Upper Devonian of that region he recognizes
nodular limestones with* Clymenia (more typically developed at
South Petherwin), 4 Cypridinen-Schiefer,' Adorf Goniatite-limestone.
1 'Ueber das Devon in Devonshire und im Boulonnais,* Neues Jabrb
1889, Band i. p. 179.
2 Trans. Devoneli. Assoc. rol. xxi. p. 44.
Vol. 50.]
AN5IVEUPAKT ADDRESS OF THK PRESIDENT.
75
Biidesheim-shales, and Ibcrg coral- and brachiopod-limestone. In
the Middle Devonian he recognizes Stringoctyhulw-limestoiiCi Cal-
ciofa-limestone, Calceola-shsiieB, and possibly also Goslar-beds. In the
Lower Devonian he finds the Upper and Lower Coblenz stages, and
* Siegen Grauwacke,' especially represented by a small but typical
fauna at Looe* This general agreement is further increased by the
appearance of numerous * greenstones/ which, just as in Nassau and
the Harz, are accompanied by schalsteins."
Mr. Usshcr'a paper relates more particularly to the area north of
the Dart and east of Dartmoor, and it is satisfactory to find that
his views aro fairly in agreement with those of Herr Kayser, the
value of whose identifications he readily acknowledges. Although
the lithological constituents of the Upper, Middle, and Lower
Devonian beds are broadly distinguishable, yet there is no definite
lithological boundary between the groups. The Lower Devonian is
mainly indicated by the occurrence of sandstone and grit ; but the
upper beds are slatos or shales passing without distinction upward
into the Middle Devonian slates. In no part of the Lower Devo-
nian of this district have igneous rocks been found. The Lowe r
Devonian of the Torquay [and Paignton areas is described with
especial attention to the fossils, and the Author embraces the oppor-
tunity of correcting a mistake into which he, and latterly also
Mr. Champcrnowne, fell with regard to the position of the Cocking-
ton Grits, which may, he says, be placed in the Lower Devonian on
paheontological evidence quite as strong as any furnished by the
Torquay promontory. He considers that at present the evidence is
not sufficient to justify the subdivision of these beds into Upper
and Lower Coblenzian.
The Middle Devonian is, of course, the most interesting series ;
and here I would remark that, in the Abstract of this paper, the
sequence differs from that given in the Quarterly Journal. Assuming
the latter to represent Mr. Ussher s final views, he makes the Ash-
prington volcanic series underlie the Middle Devonian Limestones
(vol. xlvi. p. 493), thereby apparently endorsing the opinion ex-
pressed by Mr. Worth that, in the Plymouth district, the volcanic
rocks were mainly below the limestone. Further on, however, he
remarks that the Ashprington series may represent continuous or
intermittent activity up to the middlo of the Frasnian. In ascend-
ing sequence, then, the following is now held to be the development
of Middle Devonian rocks in this area. At the base are the Eifeliau
slates, characteristically developed in Berry Park, bounded on the
Digitized by Google
76
r ROCKED I NGS OF TIIF. GEOLOGICAL SOCIETY.
[May 1894,
south by the Ashprington volcanic series, and on the east by the
Lower Devonian of Beacon Hill and Windmill Hill (Cockington Grits).
The shaly * Calceolen-kalk/ or Eifelian Limestone, which gradually
comes on in the upper part of the series is frequently brought up in
the limestone masses of Torquay and elsewhere by contortion.
Fossils common in the Eifelian slates are Atrypa reticularis, Strepto-
rhynchu* ertnistria, and Spirifcr speciosut. Both by fossil and
stratigraphical evidence the position of certain limestone patches in
connexion with the Ashprington volcanic series is proved to coincide
with the Eifelian Limestone, and we are thus supplied with a reliable
date for the commencement of this phaso of volcanic activity, viz.,
the later stages of the Eifelian deposition. This is also borne out
by the absence of volcanic materials in the Lower Devonian and
Eifelian Slate areas. How long it continued is not equally clear,
but there seems, ho says, to be evidence of vnlcanicity in other
areas in connexion with a great development of Middle Devonian
Limestone.
Continuing the Middle Devonian sequence, we have now to con-
sider the main mass of Devonian Limestone. Mr. Usshersays there
is absolutely no line of demarcation between the upper horizon of
the 4 Calceolen-kalk ' and the bedded limestones above, which are
held to be on the Strinyoctphalus-horizoTi ; hence their separate
treatment is purely arbitrary. It would take up too much time
to follow the interesting evidence, chiefly palajontological, adduced
by the Author in connexion with the Torquay, Dartin^ton, and
Newton Abbot districts. In his summary he infers, generally,
that the bedded limestones which succeeded the shelly and coralline
bands, representing the Eifelian Limestone, became in places the
bases for more uninterrupted coralline growth. This growth, he
considers, was locally continuous to the earlier stages of the Upper
Devonian period. In the meantime, proofs are not wanting that
the accumulation of Middle Devonian Limestone took place contem-
poraneously with the Ashprington volcanic outbursts ; so that, in the
words of Mr. Champernowne with reference to the stratigraphical
difliculties presented by that series : — " All these anomalous ap-
pearances are at the same time quite capable of being accounted
for, if we consider what might take place in a reef district which
was at the same time the arena of volcanic disturbance." That
gentleman's experience, moreover, fully endorsed De la Beetle's
view that certain of the limestones are laterally replaced by
slates.
ized by Goo<
Vol. 50.]
AKSl VERSA RY ADDRB8S OF TUB PKKSlDEflT.
77
With few exceptions, it is only of late years that Upper Devonian
rocks have boon demonstrated in this district, and even now
Mr. Ussher does not think it possible to draw an arbitrary boundary
in South Devon between Middle and Upper Devonian below the
nhaly Goniatite-limestonos. Consequently, his generalized sequence
in asconding order is : — Massive limestones, Goniatite-limestones
and slates, Cypridinen-Schiefer (AVomia-slates). Speaking of
the lower portions of the series (massive limestone), he states
that Dr. Kaysers list from Lower Dunscombe quarry, below the
Goniatite-beds, included lihynchondla aihoides and other well-
known brachiopods, such as might be held to infer a lower Frasnian
horizon. As regards the Goniatite-beds themselves, it is interesting
to note that there are traces of this fauna in the direction of Brix-
ham ; this is at Silver Cove, where the junction is said to be in-
verted, the thin beds of limestone occurring in their natural position
at Galmpton Point. It would savour too much of local geology to
enumerate the places where this horizon has been detected, and
yet their number is likely to be increased, if we may credit
Mr. Ussher that certain * unfossiliferous ' slates would reveal to a
patient searcher traces of the Goniatitc-fauna. Lastly, in the map
of the distribution of the Devonian rocks between the river Teign
and the Haldon Hills we notice, in the midst of a puzzling
geological complex, a considerable development of the Cypridinen-
Schiefer on both sides of the Teigu, but more especially on the
north. With the exception of the nodular limestones with Clymenia,
mentioned by Dr. Kayser, this completes the Devonian succession
in South Devon.
To sum up, we may say that if there is one point made clearer
than another by the study of this region, it is that stratigraphy
alone is inadequate to put together a geological puzzle such as South
Devon presents : where bods, which were irregularly developed in
the first instance, have been squeezed between granite-masses on
the north and an axis of upheaval on the south. If I remember
Mr. Charapernowne's words correctly, matters are still worse on
the other side of the Dart, while the difficul ties about Tavistock and
on the west side of Dartmoor generally are notorious. Mr. Ussher is
quite correct in saying that the facts established in his paper have a
much wider application than to the district described, since the
identification of the Cockington beds as Lower Devonian relates
to a large area between the Dart and Plymouth. It is significant
that in a geological map of the south-western counties recently
Digitized by Google
78 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1894,
constructed by Mr. ITsBher 1 the whole of the great triangle which
constitutes the southern lobe of Devon is coloured as Lower
Devonian. Apart from the somewhat fanciful idea of including the
Start rocks in this category, it is very much what we should expect
from indications already made known before Mr. Ussher had seen
lit to change his mind on the subject of the Cockington Grits. The
great development of Lower Devonian beds in this maritime area,
continued in a westerly direction through Looe and thence right
across the heart of Cornwall, adds to the completeness of the broad
synclinal which is the leading physical feature of the south-western
peninsula.
The Older Palaeozoic Rocks.
Silurian and Ordovkian. — I presume that it is right to include
the Aronig scries with the Ordovician, these two systems or sub-
systems thus constituting the upper division of the Older Palaeozoic.
We have had about half a dozen papers in this category. Of these,
two by Messrs. Marr and Nicholson have reference to the North-
west of England ; there is a stratigraphical paper on the Llandovery
rocks of the neighbourhood of Corwen by Messrs. Lake and Groom,
and papers on special subjects by Prof. Rupert Jones and
Mr. Wethered. There is also a note on the geology of the district
west of Caermarthen from the pen of the late Thos. Roberts,
wherein he records the discovery of the Tetrayraptus-bedB of
Arenig age, which had not hitherto been detected south of the
St. David's district.
Messrs. Marr and Nicholson's first paper relates to the Stockdale
Shales, which extend across the main part of the southern half of
the Lake District, parallel with the underlying Coniston Limestone
aeries and the overlying Coniston Flags, with both of which they are
conformable ; i. e. they are conformable to the Ordovician beds below
and to the Wenlock beds above, thus represent ing the two Dandoveiy
subdivisions and tho Tarannon Shales of the Welsh Border area.
The Authors also correlate the Graptolite- zones with those of the
Birkhill and Gala groups in the South of Scotland. Although the
wholo group, in the area examined, attains to no more than 400 feet
as a maximum thickness, the Authors indicato something like
seventeen zones or horizons, many of them distinguished by a
particular graptolite. These Stockdale Shales are regarded as being
divisible into a Lower group, viz., the Skelgill Beds, consisting
1 Prop. Somerset. Archosol. Sop. toI. xxx?iti. 1892.
Digitized by Google
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
79
mainly of dark graptolite-bearing shales, which alternate with
lighter-coloured mudstonos entirely devoid of graptolites except
where they pass into the adjacent graptolitic shales. The Upper
group (Browgill Beds) is nearly three times as thick as the lower
one, having probably been formed muc!\ more rapidly, and conse-
quently of less importance ; it consists chiefly of green and purple
shales with intcrstratified grit-bands and a few insignificant seams
of dark graptolite-bearing shales. Although there is absolute
conformity between the lowest beds of the Stockdale Shales and the
highest beds of the Ashgill Shales, the palaeontologies! break is
complete, and it is at this point that the Authors draw the line of
division between the Ordovician and Silurian systems.
One very singular fact in connexion with this enquiry, having a
wide bearing on stratigraphical palaeontology in general, is the
remarkable recurrence of graptolitic and non-graptolitic beds so
characteristic of the lower series. The subject of recurrent faunas
is well-known in several formations, and in some cases is more or
less due to changes, which partly indicate their nature by a differ-
ence in the character of the sediment. The Authors, and especially
one of them, who has ably discussed this subject before the Cam-
bridge Philosophical Society, are disposed to consider it due to
climatic changes in the present case, which is certainly one of the
most remarkable to which the attention of palaeontologists has been
drawn. There is anothor question in connexion with these beds to
which they also draw attention, viz. Are the graptolites wholly
absent from the trilobite-bearing mudstonos, and vice versa ? The
usual difficulty which attaches to the proving of a negative is
naturally felt, though they conclude that there was, possibly, com-
plete migration in some cases, whilst in others the forms may have
lingered on in diminished numbers during the period that was
unfavourable to their existence. In this latter case, they suggest
that such a lingering on would be admirably qualified to bring about
that variation in the creatures which would account for the marked
contrast between the fossil contents of beds separated by only a few
feet of intervening rock.
The Authors claim that the most important result of their
researches is the additional evidence they have furnished of the
value of graptolite- zones as a means of comparison of Lower Palaeo-
zoic rocks of distant areas. It is true that a suggestion was made
to> the effect that possibly the application of graptolitic as against
trdlobitic verniers might not produce the same results in the way of
8o PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894.
correlation. Prof. Lapworth, as might have been expected, strongly
endorsed the viows expressed by the Authors. He looked forward
(o the day when the existence of these Graptolite-zones in the
Lower Paleozoic rocks would be generally acknowledged, and that
they would be employed as a basis for classification and mapping.
He further remarked that the thin Moffat series of the South of
Scotland represented the whole of the Llandeilo, Bala, and Llan-
dovery formations in other regions. Although the general position
of the Stockdale Shales with reference to other formations above
and below was known previously, the Authors had now fixed their
horizon from internal evidence. The zones they had detailed in tbe
Lake District agreed with zones already established in the South of
Scotland, Wales, and other countries. He commented on the small
thickness of these Stockdale beds, but pointed out that they were
represented by very great thicknesses of deposit elsewhere. Thus
the Browgill or Upper Stockdale scries had their equivalent in
thousands of feet in the Gala group and the Tarannon ; whilst the
Skclgill, or Lower series, were represented by enormous thicknesses
in Girvan and Central Wales. He considered that the Authors had
accomplished a piece of work of the highest systematic- importance,
but further zone-work was required, and he predicted that it would
be followed by a re-mapping of many areas.
The same Authors have made a further contribution to our know-
ledge of the Older Palaeozoics in their paper on the Cross Fell Inlier,
which is one of the stratigraphical features of the Eden Valley-
representing a tract of Ordovician and Silurian rocks lying between
tho Carboniferous of the Cross Fell range, on the east, and the New-
Red Sandstone of the valley, on the west. This tract is about
16 miles in length, with an average breadth of rather over a mile;
and it is divided along its entire length by a fault, which separates
the Skiddaw Slates from the higher beds composing the Inlier on
the west. The district is very interesting to those who are desirous
of tracing the character and relations of the Lake District rocks in
their easterly development, after their eclipse by newer formations
in the central portion of the Eden Valley. But tho main object of
the Authors has been to fix the ages of the various formations of
the Lower Palaeozoic rocks in the Inlier, to determine their organic
contents, and to compare them with the corresponding rocks of
other areas. Even the Skiddaw rocks arc not treated in any detail :
and, although there are petrographical notices of certain sedimentary
and volcanic rocks in that series, and also of the volcanic rocks of
Digitized by Google
Vol. 50.J
ANNIVERSARY ADDRESS OF THE PRESIDENT.
8r
the Eycott and Khyolitic groups and of the principal varieties of
intrusive rocks, yet the chief interest of the paper, for my present
purpose, centres in the beds that lie above the Khyolitic group.
Succeeding the rhyolite of Knock Pike, which may be regarded
as representing the higher portions of the Volcanic Series within
the area, are some layers of fine, apparently unfossiliferous ashos,
which pass up into calcareous shales with nodular masses of lime-
stone crowded with fossils, some of the calcareous bands being
composed exclusively of the valves of Beyrichia. One bed of the
series having previously been spoken of as tho DUcina (Trematit)
corona-bed, the Authors propose to name tho whole the Corona-scries.
This is interesting from the fact that it seems to bo older than,
anything which has been referred to the Coniston Limestono group in
the Lake District proper. The fauna is a very marked one, entirely
different from that of the ordinary Coniston Limestone, nor has any
similar fuuna been hitherto recorded from tho British Islands.
The next beds in ascending order are the Dufton Shales and
Keisley Limestone, which are held to be referable to the same sub-
division, notwithstanding their lithological dissimilarity. Most of
the Dufton Shale fossils aro said to be common in tho Coniston
Limestone, the Bala Limestono, and the Trinvcleus-BhaXeH of
Sweden; and the Authors hold that the Dufton Shalos, if not
actual representatives of the Coniston Limestone, are far more
closely allied to it than to the underlying Corona-beds with which
they have hitherto been associated. The group of fossils in the
Keisley Limestone is essentially that of the Coniston Limestone, but
there are some curious differences. Tho Stau rocep Art?«*-limcstonc
and the Ashgill Shales complete the column of the Coniston Lime-
stone series, and, as we have already seen, are regarded by the
Authors as constituting the summit of the Ordovician system. The
whole, including the lihyolitic group, is regarded as of Bala age,
the term being used as synonymous with Curadoc, so that the
lx>wer Bala of that district in the sense used by tho Authors is not
Llandoilo.
Turning our attention now to North Wales, we have lately had
a paper on the Llandovery and associated rocks of the neighbour-
hood of Corwi n by Messrs. Lake and Groom. It seems to have
been for some time a doubtful point whether true Llandovery rocks
are represented in tho northern part of Wales ; but in 1877 Prof.
Hughes concluded that the grit at Corwen is of Llandovery age,
and that it forms the base of the Silurian in this area, which include**
Digitized by Google
82 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
a part of the northern slope of the Berwyn Hills stretching along
the southern bank of the Dee. The stratigraphy of this slope is
worked out with much care. No fossils have as yet been found in
the Corwen Grit, but there is a grit at Glyn Ceiriog, occupying a
similar position, which has yielded many. The Authors conclude
that the Corwen Grit clearly forms the base of the Llandovery in
this area, whilst between it and the Tarannon Beds are black shales
containing numerous graptolites of the Monograptus gregarius-zone.
Their researches were still insufficient to show whether Upper Bala
rocks are absent or not from the region, though the evidence at
Corwen itself seemed distinctly in favour of a break.
Cambrian. — We are now approaching the lower limits of the
pahcontological column, and there is a corresponding difficulty in
the arrangement of the subjects, owing to the existence of beds
which some authors regard as Cambrian and others as pre-
Cambrian. So long as there are any remains of a fauna to guide
us we are on tolerably safe ground, and it thus seems advisable to
separate papers which contain references to paheontologieal evidence
from those entirely based on stratigraphy and petrology. Under
the description of palseoutological evidence one would be disposed to
exclude for present purposes most of those enigmatical markings
which have been noted, from timo to time, in beds presumably
underlying the fossiliferous Cambrians. Such beds may ultimately
yield to research a distinctive fauna, but at present they must be
regarded as mere aspirants to rank in the palseontological column,
and are for that reason best placed in the category of 4 Fundamental
Rocks.' An exception may be made in tho case of the Pipe-rock of
Assynt, which, although below the lowest recognized Cambrian fauna,
must certainly be included with that system, and this also may carry,
as hinted by Prof. Sollas, certain rocks in the neighbourhood of
Dublin which were once claimed by Prof. Blako as Upper Monian.
The papers dealing with the fossiliferous Cambrian arc not
numerous. If we exclude those which treat of the Longmynd and
the volcanic series from a Btratigraphioal and petrological point
of view, there aro not more than half a dozen. North Wales
receives notice from Dr. Woodward in his paper on < Trilobites in
the Cambrian green slates of the Penrhyn Quarries.' The papers
by Sir J. W. Dawson on the Eozoic and Palaeozoic rocks of the
Atlantic coast of Canada refor to the whole of the Palaeozoic series
and include likewise ample notices of the Fundamental Rocks. It
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT.
is, however, in respect of the f ossiferous Cambrians and correla-
tions of these with European strata that I am desirous of quoting
them. This veteran Author alludes to the fact that, of 43 papers
contributed by him to the Journal of the Society since 1845, 10
relate to Eozoic and older Paheozoic, 29 to Devonian and Carboni-
ferous, and 4 to Mesozoic and Modern. The Cambrian geology of
Scotland has received considerable attention of late years. The
paper by Sir Archibald Geikie on the 4 Ago of the Altered Lime-
stone of Strath in Skye ' may be included under this head. Then
there is a considerable portion of the wonderful memoir by Messrs.
Peach and Home, which was justly described as three or four
paj)ers rolled into one, and lastly the paper by the same Authors
on the Olenelhts-zone in the North-west Highlands.
Beginning with a very low horizon of fossiliferous Cambrian
in North Wales, I may remark that some time has now elapsed
since Prof. Dobbie forwarded to Dr. Woodward specimens of a trilo-
bite from the Penrhyn slate-quarry which the latter, on comparing
with Parad oxides, Angelina, Oyygia, and Olemts, concluded to placo
in tho genus ConocoryjJw, naming the species C. viola. This fossil
is interesting from the fact that, so far as I know, it is the lowest
fossil belonging to an undoubted Cambrian facies which has
hitherto been discovered in North Wales, although, according to
the remarks of Dr. Hicks at the time, the lowest fossiliferous
horizon at St. David's is yet older. Subsequently he observed that
Mr. Walcott, in his recent memoir on the Olenellus-fauno,, said that
the Conocoryphe viola-zone of the Penrhyn quarry must be included
in the Lowest Cambrian. As a matter of fact tho specimens of
Conocoryphe viola wore obtained from the upper green bed of the
quarry, which immediately underlies the grits forming the brow of
Bronllwyd, and consequently above the Purple Slates. Speaking at
the timo when the paper was read, Dr. Hicks said that the position
of the fossils seemed to be above the Llauberis Slates, but at the
'>ase of the Harlech Grit series. In view of tho questions raised by
Prof. Blake, to which I shall have to call your attention presently,
it is of some importance to bear these things in mind.
It will be necessary now to refer to Sir J. W. Dawson's papers,
*o far as he correlates American with P^uropcan Cambrians : one
chief object of the Author being to compare the Cambrians of the
Acadian provinces with those of the interior of America on the
one hand, and of Western' Europe on the other. It may bo that
Palaeozoic geologists are by no moans unanimous in accepting all
84
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
[May 1894,
these correlations, and there is one error of some consequence which
Dawsoo, at the time the papers were written, shared with other
Transatlantic authors, viz., in placing the Ok/ieJ/wa-fauna above
that associated with Paradoxidet. This mistake was corrected by
Brbgger, who demonstrated that in Scandinavia the Olencllus-zone
was at the base of the Cambrian, being succeeded above by the
Paradoxides-zone ; and, according to Dr. Hinde, Mr. Walcott has
lately verified this sequence in America.
It would appear from a perusal of Sir J. W. Dawson's first paper
that he was there disposed roughly to divide the Cambrian System
into three great series, distinguished respectively by Paradoxidef.
Olendlus, and Dikclocephalus. The former fauna, he remarked, is
unknown over the great continental plateau of America, whilst
the second, or Olenellus-group, slenderly represented on the coast,
appears in forco immediately within the great Laurentian axis
of Newfoundland, being likewise known in the valley of the
St. Lawrence by the great masses of limestone full of fragments of
Olenellugy Solcnopleura, l/yolithes, etc., found in the conglomerates
of the Quebec group. Of the upper members of the Cambrian, the
Dikelocephalue-gToup, or Potsdam Sandstone, is apparently altogether
absent in the Acadian provinces. It seems doubtful if any good
equivalent of the Potsdam exists in England or Wales. For a long
time this same Potsdam Sandstone was regarded by the geologists of
America as constituting the baso of the Palaeozoic column, since over
great areas of Canada and the United States it lies unconformably
and directly on the Laurentian. The marginal areas of the Con-
tinent have since afforded a great series parallel to the Cambrian of
Wales and Scandinavia. In further illustration of this we find at
Alatane and Cape Hosier true Trcmadocs (regarded as a passage-
series between Cambrian and Ordovician) filled with Dictyonctna
socuilt and containing fragments of characteristic trilobites. Farther
inland, on the main American plateau, these beds are not fouod,
but are represented by the peculiar 4 Calciferous ' formation, a
dolomite formed apparently in an inland sea and having a charac-
teristic fauna of its own. The Author then observes that in the
sandstone and limestone series of Durness a group of fossils was
long ago recognized by Salter as being of this interior-American
type, which docs not exist either in Wales or on the American
coast. He concludes that the trilobitio and graptolitic faunas of
the coast mainly belonged to cold northern currents ; whilo the
• Plateau faunas ' — richer in cephalopods, gasteropods, and corals
Digitized by Google
Vol. 50.J
ANNIVERSARY ADDRESS OK THE PRESIDENT.
85
— belonged to the superficial warm currents passing over shallow
plateaux, or to the tepid waters accumulated in closed basins,
though we may imagine that theso latter might not especially favour
the growth of reef-corals.
We must now consider tho report of Messrs. Peach and Home on
the recent work of the Geological Survey in the North-west High-
lands, in so far as it refers to tho development of bods of Cambrian
age within that area. It has long been known that there is a
marked discordance between these and the underlying formations ;
so that the base of the system is well-donned, and there is not
that obscurity about it which obtains in other areas and notably in
North Wales. Tho lowest beds of the whole series are false-bedded
grits and quartzites with brocciated conglomerates at the base. The
total thickness of the arenaceous or quartzito series is about 500 feet,
the upper half being distinguished as the 4 Pipe-rock,' owing to the
number of vertical pipes of Scolitfws with which it is permeated.
Tho middle group is limited in thickness. The lower portion
of it, from 40 to 50 feet thick, is known as the 4 Fucoid '-beds, a
very mixed series, often a matted network of the flattened excrement
of worms — an appearance misleading the old observers, who re-
garded them as the remains of seaweeds. Above this is the
curious formation known as the Serpulite-, or more correctly SalU-
rcZta-grit, about 30 feet thick, passing upwards into the * calcareous
scries.' Here, again, the old observers were mistaken, SalttreUa
being a pteropod, tubular in shape and consisting of several hollow
cones placed one within the other. The 1 calcareous ' series has a
thickness of 300 or 400 feet, and is divided into seven groups, all of
which are developed at Durness, and it is the highest but one of
these groups which has yielded the bulk of tho fossils. In the line
of complex structure, south of Durness, it is only tho lower,
generally the lowest group, which occurs ; and thus the unfossili-
forous character of the Cambrian Limestones in Assynt and other
localities is, to a certain extent, explained.
A brief notice of Mr. Peach's excellent summary of the physical
conditions of deposit and horizon of theso North-west Highland
Cambrians seems appropriate at this stage. In the case of the basal
quartzites, he says, where there is a passage from a land-surface
to a sea-bottom, little or no organic matter was mingled with the
coarse siliceous sand ; consequently there was no food for the
support of tho annelids, which became so numerous in tho upper
beds of the quartzite. Hence the * Pipe-rock ' indicates slower
vol. l. g
Google
86 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
accumulation, affording time for the fertilization of the sand hy the
shower of minute pelagic organisms. Truly this was the age of
worms, that continued masters of the situation through the period
represented by the * Fucoid '-beds. The * Serpulite '-grit is evidence
of coarser sediment, but after its deposition hardly any material
derived from the land entered into the composition of the overlying
limestones. Eventually, he continues, nothing seems to have fallen
on the sea-floor but the remains of minute organisms, whose calca-
reous and siliceous skeletons have slowly built up the great mass of
limestono and chert so conspicuously developed at Durness. Worms
were still in the ascendant, since most of the beds are traversed by
worm-casts in such a manner that nearly every particle must have
passed through their intestines. Indeed, he considers that the
prevalence of these annelid-traces indicates that the limestones
cannot be due to coral-reefs. Moreover, only one undoubted speci-
men of a coral, resembling a Michclinia, has been observed. Neither
had shell-banks much to do with the accumulation of the limestone,
as may be seen from the mode in which the shells occur. The most
abundant forms are chambered shells, such as Nautilus, Lituitcsy and
genera of the Orthoceratid®. Next in order are the gasteropoda,
chiefly Madurea (heteropod), and Pleurotomaria, whilst the lamelli-
branchs and brachiopods rank last in point of numbers. Sponges
of the genera Archceocyathus and Calaihium occur at intervals in the
muddy matrix. However, the larger masses of chert in the lime-
stone do not seem to be derived from sponges, but more probably
from the siliceous skeletons of diatoms. No undoubted remains of
foraminifera have been discovered, and he thinks it unlikely that
minute organisms would bo preserved, owing to the fact that the lime-
stones are crystalline and that many of them are more or loss
4 dolomitized.' This latter word is the only one to which I would
take exception. If we substitute « dolomitic/ it will leave open the
question of origin, which I think may be important in this case.
Mr. Peach endorses the views of Salter that the fossils are of an
American type. So far as the order of succession of the beds is
concerned, we have, he says, an almost exact counterpart of the
strata exposed along the axis of older Paheozoic rocks, stretching
from Canada through the Eastern States of the Union. His
inferential correlation of the * Pipe-rock ' of Sutherland with the
Potsdam Sandstone, based on the prevalence of Scolithut, will
scarcely hold good in view of the later researches of the Survey.
Tho correlation of the Durness Limestone with the 'Calciferous
Digitized by Google
Yol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
Group ' is probably nearer the mark. The subsequent discovery of
the Olenellus-zojie in the ' Fucoid -beds may perhaps induce Mr. Peach
to regard the Durness fauna as probably an Upper Cambrian one.
We should now seek for a parallel to the Durness Limestone in
other parts of Scotland, outside the area technically known as the
North-west Highlands. This may be found, according to Sir
Archibald Geikie, in the Altered Limestone of Strath in Skye,
which had been regarded by great authorities as an instance of
contact-metamorphism in a rock of Liassic age. Many years ago
the Author expressed a suspicion that this rock might turn out to be
of the age of the Durness Limestone, and recent investigation has con-
vinced him that such is tho case. In lithological characters the rock
differs from the Lias of the district, consisting in its lower part of
dark limestones full of black cherts, and comprising a higher group of
white limestone with little or no chert. Moreover, white quartzite
is found in association with the limestone at several places in
Strath ; also representatives of the well-known 4 Fucoid '-bods at
Ord in Sleat. These latter strata form a persistent band which
may be traced from Sutherland into Skye. The pakeontological
evidence is also favourable. It would seem that the Lias rests upon
this Cambrian limestone unconformably, and actually contains at
its base a coarse breccia largely composed of pieces of tho older
limestone along with fragments of chert and quartzite. Tho most
singular thing is that the metamorphism is stated to be confined to
the Cambrian limestone and to have been produced by large bosses
of granophyre (syenite) of Tertiary age. Mr. Marr considered that
the recognition of the Durness Limestone in Skye might be expected,
and referred to the Stinchar Limestone of the Girvan district as
being of the same age, viz., that of the Orthocercu-limestono of
Sweden.
A further advance has been made in tho survey of the Cambrian
;irea of the North-west Highlands by tho discovery of Olendlus in
the « Fucoid '-beds and * Serpulite '-grit of the Dundonnell Forest in
Ross-shire. Particulars are given by Messrs. Peach and Horn© in a
recent communication to the Society, wherein they comment upon the
remarkable persistence of the sub-zones already identified in Assynt
and at Loch Eriboll. The basal quartzites are, for the moat part,
destitute of those worm-casts so characteristic of the overlying zone,
but in the Ben Eay forest, south of Loch Maroe, certain dark grey
shales, which may probably yield organic remains at some future
time, occur near the base of the series. The five sub-zones in the
92
Digitized by Google
88 PROCEEDINGS OF THE GEOLOGICAL 80CIETT. [May 1804,
overlying * Pipe-rock/ based on the peculiar features of the vertical
burrows in the quartzite, are also found to hold good, having been
traced even south of Loch Maree. In the third sub-zone SaUerdla
lias been noted on Ben Arkle (Sutherland) in a massive quartzite
free from vertical worm-burrows, and a similar band without the
4 serpulite ' has been noticed in the Loch Maree district.
We now come to the details of the discovery of Olewllu*. The
1 Fucoid '-beds, it would seem, preserve their character as brown
dolomitic shales with bands of rusty dolomite ; and it is in the
upper portion of this series that fragments of this early trilobite
were first found. A mountain-stream has cut a natural section,
and the attention of the observer, wo are told, is at once arrested
by two prominent bands of dark blue shale, intercalated in the
normal dolomitic beds of the zone. The upper band is about 3 feet
and the lower one about 9 feet from the top of the 4 Fucoid '-beds,
and it was in the lower band that the fragments were found, the
best specimens being confined to a seam less than an inch thick*
It would also appear that dark blue shales, near the top of the
' Fucoid '-beds, have been observed in various localities, evidently
occupying the same horizon as the Olenellus-sh&les in the I>undonnelI
Forest. The Authors were sanguine at the time that these shales
would be traced continuously through a great part of Ross-shire.
The locality where the trilobites were found in the zone of the
4 Serpulite '-grit is about 8 miles N.N.E. of Loch Mareo. At thi»
spot a small escarpment gives a full section of the zone, here
about 36 feet thick, consisting of quartzite and quartzose grits with
a little shaly matter here and there, especially in the lower half.
In a band of dark blue shale in the lower part of this formation a
head-shield and other fragments of Olcnellus were found, the specie*
being apparently the same {0. Lapworthi) as that occurring in the
'Fucoid '-beds.
Of the organic remains obtained from the dark shale-t and* frag-
ments of trilobites are the most abundant, but with these are
associated the remains of ptcropods, among which a $<ilier»U<i like
S. jmlcJulIa occurs. Several species of Uyolithm also are found,
besides one specimen of a large entomostracan. The asKO«ia'i°n ^
Salterdla with Olcnellus, say Messrs. Peach and Home, induces a
hope that traces of this trilobite maybe found wherever the 'Serpu-
lite'' has been shown to abound, possibly even in thelcwrst potipof
limestone. After these discoveries it could no longer le donated that
the Quartzite, 4 Fucoid '-beds, and 4 Serpulite '-grit belong to a very
Digitized by Google
"Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 89
low horizon in the Cambrian System, and the authors even intimate
that the lowest beds of the limestone may belong to the same category.
As regards correlation of this horizon with other areas, it has been
stated by Dr. Hicks that no definite Ol&iellus-fauna, hud been dis-
covered at St. David's, but he believed that the horizon was indicated
by the Lingulella prinurva-zone, which occurs near the base of the
Cambrian and several hundred feet below the lowest Paradoxides-
beds. Subsequently he remarked that he had found fragments of
Olcnellus at St. Davids associated with a species of Conocoryphc.
Amongst other facts of interest connected with the palaeontology of
this horizon, the probable association of Olenellus with SaltercUa, as
pointed out by Dr. Woodward, from beds at Kimberley in Western
Australia, seemed to indicate the existence of Lower Cambrian in
that continent also.
Physical Relations ami Post-Cambrian Metamorphism of the Rocks
in the North-west Highlands. — With the account of the discovery of
the Olenellus-fauna. in this region the study of the fossiliferous
Cambrian terminates. Henceforth we havo no further concern
with a definite palaeontology, and must consequently fall back upon
such other indications as may be available. Before venturing on
the wide subject of the Fundamental Rocks, or the yet wider one of
the Miscellaneous Rocks, I am reminded by a glance at Messrs.
Peach and Home's sections, in North-west Ross-shire, how greatly
our knowledge of the whole region from Loch Eriboll to the neigh-
bourhood of Loch Mareo has been increased of late years. The
history of these investigations is well known to most of you, and
part of the story was well told by Prof. Bertrand in the Geological
Magazino about a year ago.1 Now, we have it on record that
.Messrs. Peach and Home's first communication to the Society re-
sembled several papers rolled into one. It treats, in fact, of a
variety of subjects in connexion with the geology of the North-west.
Amongst these subjects are the physical relations and post- Cambrian
metamorphism of the various rocks which make up the district.
As the events in which the Cambrian rocks were involved are held
to have taken place previous to the deposition of the Old Red Sand-
stone, they clearly belong to some portion of Older Palaeozoic time,
and may therefore be considered in connexion with the rocks of
that period.
The remarkable series of sections which the Authors exhibit in
' Geoi. Mag. 1893, pp. 118 seqq.
90 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,.
illustration of the physical relations of the strata cannot fail to call
to our minds some of the efforts of previous authors, who, without
the key, were vainly endeavouring to explain on ordinary strati-
graphical principles the remarkable phenomena along the line of
chief disturbance. It is claimed for Prof. Lapworth, and perhaps
not unjustly, that he, working with tools forged by himself, has
given the key to the geology of two great provinces of Scotland.1
At least in this district we may allow that he materially assisted in
opening the eyes of the officers of the Survey and others to the possi-
bilities of the case, and that the former have not been slow to profit
by his teaching. Nine years have now elapsed since the close of the
Highland Controversy, and the interval has been one of steady pro-
gress in recognizing the true, but nevertheless extraordinary, struc-
ture of the country. Well indeed might Prof. Lapworth comment
on the descriptive character of this portion of Messrs. Peach and
Home's paper, whilst allowing that the general conclusions arrived
at were very similar to those which he had himself indicated. Such
sections are, to a certain extent, astounding, yet they do occur.
The subject of Thrust-planes has been pretty well grasped by this
time, and some people have been looking for them where probably
they do not exist. The three chief thrust-planes of this region in
order from west to east are — (1) the Glencoul Thrust; (2) the
Ben More Thrust ; (3) the Moine Thrust. A series of horizontal
sections drawn across the general strike of the district exhibits the
effects of one or more of these in combination with the results of
minor thrusts. Nothing but the most intimate acquaintance with
each particular rock could ever have enabled the authors to put
together the pieces of such an extraordinary jumble, though when
once the idea is grasped there seems to be a certain amount of
system in the displacements. One of tho more northern sections,
about five miles in length, exhibits the wonderful manner in which
a swirl of the Cambrian beds, from quartzite to dolomite all told, is
caught up, as a kind of inlay, into the flanks of the Archaean gneiss.
It was the re-appearance of this Archaean gneiss, far to the eastward
of its accepted position, which so puzzled the older geologists, often
figuring as the * igneous rock ' of Murchison or the 4 Logan rock ' of
Heddle. Such, within certain limits, is the structure of Coniveall,
the southern peak of Ben More of Assynt. This structure, at the
Stack of Glencoul, is further complicated by an outlier of the eastern
or Moino Schists, brought forward several miles to the westward of
1 Bertrand, op. cit. p. 121. f
Digitized by Google
Vol. 50.] ANNIVKBSABY ADDRESS OF THE PRESIDENT. 9 1
their original position by the effect of the Moino thrust-plane — that
most terrible of all deceivers. The horizontal section from the
Knockan Clifb to the Cromalt Hills is another edition of the same
story. It is needless to say that such classical sections as Cnoc an
drein, Coniveall, Ben More, and Breabag, with all that wonderful
slicing and plication which each exhibits more or less, are dealt with
in a fashion that leaves no doubt, when once the key has been obtained,
as to the true structure of those remarkable localities. The section
across Ben More shows at a glance what a large proportion of this
mountain-range consists of Archaean gneiss with its characteristic
basic dykes. To use, with a slight modification, the words of the
Authors, the slice of Archaean rocks, bearing the thin capping of
Torridon Sandstone and Cambrian strata which constitute the actual
summit, is of large dimensions. Here the Archaean gneiss with its
basic dykes is exhibited in a grand cliff about 1500 feet high over-
looking Dubh Loch More, whence it sweeps across the lofty peaks
separating the Oykel from the Gorm Lochs. Though still recognizable
as a part of the old Archaean platform, the rocks are stated to have
undergone important changes due to the movements which have
affected them. It was these changes which formerly prevented
geologists, Nicol in most instances excepted, from recognizing an
old friend under such altered circumstances.
We must now proceed to consider the nature of the metamorphism
resulting from these post-Cambrian movements. The Authors observe
that with each successive maximum thrust there is a progressive
alteration in the displaced materials. Por instance, the great slice
of Archaean rocks brought forward by the Glencoul Thrust does not
present any striking evidence of deformation, except close to the
lines of disruption. The alteration of the Archaean rocks is more
pronounced above the horizon of the Ben More Thrust in Assynt,
but it is in the belt of sheared gneiss and green schist underlying
the Moine thrust-piano that we have the most remarkable evidence
relating to this kind of metamorphism.
In the basal conglomerate, or 4 Button-stone/ of the Torridon
Sandstone the softer pebbles of gneiss and the fragments of the
basic Archaean dykes have been crushed, flattened, and elongated in
the direction of movement. Indeed, in some cases, they have been
drawn out to such an extent as to form thin lenticular bands of
micaceous or hornblende-schist flowing round the harder pebbles of
quartz- rock. The original gritty matrix has been converted into a
Digitized by Google
92 PROCEEDINGS OP THE GEOLOGICAL 80CrETT. [May 1894,
fine, micaceous, chloritic schist showing exquisite * flow-structure,*
winding round the elongated pebbles in wavy lines — in fact the
matrix has been converted into a fine crystalline schist. In the
grits, etc., of this formation cleavage-planes have been developed,
dipping in a direction opposite to that of the original bedding, and
more or less parallel with the plane of the maximum thrust. As
the materials differ in their powers of resistance the planes of
schi8tosity,in some cases, form a series of sigmoidal curves. Lenti-
cular veins of pegmatite occur more or less parallel with the new
schistose planes, whilst sericite is found to be abundant in the finer
bands.
The various members of the Cambrian series underlying the
Glencoul thrust-plane show little alteration, oven when they have
been piled on each other by minor and major thrusts, but above the
Ben More thrust-plane a greater amount of alteration takes place,
the steps in which may be traced until such a bed as the 4 Serpulite-
grit ' becomes a quartz-schist in which ' serpulitcs ' are no longer
visible : meanwhile the limestone becomes crystalline. As regards
the post-Cambrian metamorphism of the intrusive igneous rocks,
there is a certain progressive change from west to east. Thus,
shoots of felsite injected along the bedding-planes of the basal
quartzites have been converted into soft sericite-schists ; and in
another place a felsite-dyke on the same horizon has had cleava^v
developed parallel to the plane of the princi]>al thrust, whilst but
little alteration is noticed in the quartzite itself. Where the altera-
tion is extensive, as in the neighbourhood of the Moine thrust-plane,
the various igneous bands lose their distinctive characters : the
fino-grained diorites in the limestones are represented by green
hornblende-schists and chlorite-schists ; the noncrystalline rocks
with porphyritic felspars appear as bands of ' augen-gneiss ' and
* augen-schist ' ; and finally, along a line of powerful thrust in the
great granitoid sheet east of Loch Borolan, there is a belt of * augen-
gneiss' with pyroxenes, which, existing originally as porphyritic
crystals, now appear as ' eyes ' in the foliated rock.
As rightly pointed out by Messrs. Peach and Home, there is much
valuable information to be gathered from a study of this progressive
metamorphism. Amongst other inductions it is obvious that the
crystalline rocks, where they occur in thin sheets, become schistose
more readily than the ordinary clastic rocks. As might be expected,
too, the Torridonian sandstones and shales are more easily cleaved
than the Cambrian quartzites. In fact, whon we bear in mind
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRE8IDENT. 93
that much of the Torridon Sandstone is of the nature of an arkose,
whero the felspar has suffered very little from leaching — where,
indeed, the rock is chemically unexhausted — it is not surprising
that such a rock lends itself to metamorphism of any kind much
more than one whose composition is simpler. As to the Archaean
rocks, the thicker slices successfully resisted the extremity of
metamorphic action. Not, they say, until we reach the point
where powerful thrusts follow each other in rapid succession, re-
peating thinner slices of the old Archaean platform in the overlying
quartzites, is the post-Cambrian shearing strongly marked in the
Archaean rocks. At length, in the zone of green schist and sheared
gneiss underlying the Moine Thrust, each divisional plane or folia-
tion-surface is a shear-plane developed by these post-Cambrian
movements.
For my own part, I am disposed to believe that this wonderful
piece of dynamic metamorphism has no great depth in it. We may,
however, agree in a general sense with the Authors, in their claim
that these facts furnish a large amount of ovidenco in support of
the theory that regional metamorphism is due to the dynamical and
chemical effects of mechanical movements acting alike on crystalline
and clastic rocks. But, although we may admit likewise that, in a
certain sense, regional metamorphism need not be confined to any
particular geological period, yet there are degrees in these matters,
and surely, when it comes to a question of amount, the balance of
result will be largely on the side of the Archaean metamorphic
forces. In making this calculation I must confess that I never had
much faith in an attempted explanation of the origin of the Moine
Schists, whose crystalline character, notwithstanding their inclusion
of Cambrian fragments, is probably of much older date than the
movements which brought them into their present position. Never-
theless t he Moine Schists make a very hard nut to crack, and possibly
Prof. Bertrand's suggestion, that they are more or less to be likened
to the micaceous schists and phylladcs which in Franco form the
top of the crystalline series, may not be very far from the mark.
The Fundamental Rocks.
These may roughly be divided into three categories, viz. the sedi-
mentary series, the volcanic series, and the crystalline schists. The
first includes the unfossiliforous * Cambrian' of Wales, the Longmynd
rocks, the Torridon Sandstone, etc. The volcanic series may perhaps
include the Pebidian of Wales, the Uriconian of the West Midlands,
etc. ; but as the entire volcanic series of Britain has already been
PROC KKDIN08 OF THE GEOLOGICAL SOCIETY. [M*y 1894,
very folly treated from this Chair, it is not my purpose to deal with
pre-Cambrian volcanic rocks on the present occasion, except in part
as to their possible relations with the sedimentary series.
When we bear in mind that the pre-Cambrian volcanic series is
of considerable importance, its elimination materially diminishes
the amount of matter which has to be dealt with. Practically we
are limited to the sedimentary series and to a portion of the crys-
talline schists. There have, of course, during the past seven years
been a very great number of papers of a more or less penological
nature, where the rocks described may or may not belong to the
Fundamental group. The following authors, however, have written
papers on rock-groups whose position below the fossiliferous Cam-
brian cannot be doubted. These are Messrs. Peach and Home.
Blake, Callaway, and ltutley, and Miss Raisin. The bulk of this
literature relates to Wales and Anglesey, but Shropshire and the
Malveras come in for a fair share.
Oddly enough, the best defined pre-Cambrian, or Fundamental
sedimentary series, is to be found in the North-west Highlands, a
district which only a few years ago was an enigma, but which we
hope may now supply a clue to regions apparently more obscure.
At length geologists have discovered a pre-Cambrian system which
has a well-defined base and an equally distinct summit. It may be
said that this is no discovery, after all, since the Torridon Sandstone
has attracted attention ever since the days of Nicol and Murchison.
But we owe to Messrs. Peach and Home, in the first place, the clearest
proofs that the Torridon Sandstone is unconformable to the overlying
system, a fact which was disputed in tho * Quarterly Journal * not very
many years ago. Secondly, the same authors having demonstrated
on pala3ontological grounds the Lower Cambrian age of the over-
lying series, it follows that the Torridon Sandstone, though entirely
sedimentary and unmetamorphosed, is of pre-Cambrian age, and
there seems no reason why it should not prove to be fossiliferous.
Indeed, hopes have been expressed that a fauna might be discovered,
but as yet I have not heard of these hopes having been realized.
It would appear that there is a considerable amount of variety,
within the area, in the formation known as the Torridon Sandstone.
As far as I myself remember it, the grits partake very much of the
nature of an arkose, showing that tho felspar-fragments had not
suffered extremely from kaolinization,and thus pointing to rapid accu-
mulation. Much of the material appears to have been derived from
rocks similar to the underlying Lewisian gneiss. In the far North-
Digitized by Google
Vol. 50.J
ANNIVERSARY ADDRESS OF THE PRESIDENT.
95
west, according to Messrs. Fcach and Home, the formation has a
maximum thickness of about 1800 feet, in which they recognize
four subdivisions, including an angular basal breccia, which occurs
at any horizon where the domes of the generally level gneissic plat-
form project through the Torridonian deposits. Above this is a
conglomerate which presents features of special interest, as the com-
ponent pebbles have not been derived from the underlying gneiss.
These pebbles point to the existence of an older series of sedimentary
deposits and volcanic rocks (slaggy diabase-porphyrite), no trace of
which has yet been met with throughout the Archaean (in this case
Lewisian) area. Dr. Hicks, who generally has an eye to possible
Pebidians, noticed the occurrence of rocks foreign to the district in
the Torridonian conglomerate of Koss-shirc some years ago. The
formation thickens towards the south, attaining about 4000 feet in
Assynt, and even 8000 feet in the Loch Broom district, but the
distinctions observable in the north cannot hero be made out.
Amidst masses of coarse sandstones, grits, and occasional bands
of conglomerate, are, in places, both high and low in the series,
shaly beds with indications of organisms. Worm-casts are also
noticed in the upper beds, and quite low down in the series are
calcareous rods of an enigmatical character.
I have been somewhat particular in giving the details of the
Torridon Sandstone, because of its well-denned position as a local
series, which may some day give rise to an independent system ;
though this, perhaps, is expecting too much, when we bear in mind
how numerous are the claimants for the obscure and barren territory
between the Archaean and the fossiliferous Cambrian. The rocks
of Howth Hill and Bray Head, for instance, despite the claims of
Prof. Blake to place them in his Upper Monian, aro still regarded by
Prof. So 11; is as possibly of Cambrian age.1 Referring to the occurrence
of organic remains in the quartzite of that district, he says that their
appearance so forcibly recalls that of the Cambrian in Sutherland,
that one instinctively looks for the worm-tubes of that region, and
though repeated search in the thick massive quartzite has failed to
reveal them, yet in certain of the thinner beds similar markings
are far from rare. He refers to the discovery in a greenish quartzite,
a little south of Bray, of a number of largo burrows with an ex-
panded trumpet-like opening 3 inches in diameter, and singularly
resembling the * trumpet-pipes ' of Assynt. This is the Histioderma
hibernicum of Kinahan. Again, as Prof. Hollas observes, near the
1 Proa QeoL Assoc. toL xiii. (1893) p. 04.
•96 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
Needles of Howth,in pinkish-coloured beds of sandstono, innumerable
small worm-tubes, about £ inch in diameter, occur running trans-
versely to the planes of bedding, and these seem equally to recall
the * small pipes ' which occur on the lowest annelid-horizon of
Sutherland. We must not forget, however, that worm-casts have
been noticed in the upper beds of the Torridon Sandstone.
Crossing St. George's Channel, we find ourselves in Anglesey, a
land of pre-Cambrian mysteries, which I scarce venture even to
glance upon. The older rocks of the island have been described
with tho most careful detail by Prof. Blake in his comprehensive
paper on the Monian System ; but since that author's conclusions
have already been discussed in a previous Presidential Address, it
would seem like a work of supererogation to dwell on this topic at
any length on the present occasion. It will be remembered Prof.
Blake desired to show that the whole of the rocks which, under
various names, had been described as pre-Cambrian constitute a single
well-characterized system, of which the various divisions hitherto
described are integral and inseparable parts. These rocks are found
in six districts of Anglesey. The Lower Monian is represented by
grey gneiss and mica-schists, quartzites, chloritoid and chloritic
schists ; the Middle Monian is represented by a volcanic facies and by
a slaty facies. The South Stack series also belongs here, but in the
map showing the distribution of the Monian rocks in Anglesey no part
is assigned to the Upper Monian, although it would appear that the
Howth Hill and Bray Head rocks, previously mentioned, are regarded
as possibly tJpper Monian. Of course it is well known t hat the authors
and originators of the other pre-Cambrian systems do not look with
favour upon tho Monian system, which, like Aaron's rod, seemed
likely to swallow up the rods of the other magicians. Into this
controversy I must not enter, the more so as it would involve the
consideration of points already discussed by Sir Archibald Geikie.
It is enough to indicate that the Director-General of the Geological
Survey has still more recently given his opinion that the coarse
gneisses of Anglesey present some striking external or scenic resem-
blance to portions of the Lewisian rocks, whilst the schists, quartz-
ites, and limestones of that island present a close resemblance to the
Dalradian of Scotland and Ireland ; the quartzites, like those of the
Highlands, containing worm-burrows.1 Dr. Hicks still more
recently quotes these opinions as practically endorsing his own
views : names apart, where Sir Archibald sees Dalradian, he mainly
1 4 Journal of Geology/ voL i. pp. 12, 13.
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT* 97
- sees Arvonian — that is all the difference 1 ; whilst Prof. Blake,
writing in 1890. stated that, at that time, none of the pre-Cambrian
or Monian rocks of Anglesey had been definitely identified with rocks
elsewhere.3
The Monian controversy now transfers itself to Shropshire. Prof.
Blake, it would seem, had suggested that the Longmynd rocks were
referable to the Upper Monian. Writing in the spring of 1890, he
* : finds that they are divisible into two groups, of which the lower
only can be thus referred. The upper of these two groups, accord-
ing to Prof. Blako, represents the true Cambrian, and the junction
between the two groups is unconformable. Moreover, the volcanic
rocks on the east, associated with Caer Caradoc, are not Middle
Monian as formerly supposed by him, but represent the interval
between Monian and Cambrian, or, in other words, they are above
the lower Longmynd group, and may possibly be on the horizon of
the Bangor scries, which for him is part of the unfossiliferous
Cambrian. It is alleged that this position is supported by detailed
stratigraphy. On the other hand, there followed a rejoinder from
Dr. Callaway in his paper * On the Unconformity between the Bock-
systems underlying the Cambrian Quartzite in Shropshire;
This paper resolves itself into a series of negations as to Blake's
position. Thus, the ielsites regarded by himself as Archaean have
not been shown to be intrusive in the Longmynd rocks ; neither
has it been proved that the Longmynd series is divisible into two
groups separated by an unconformity. Also, the conglomerates and
grits associated with the Uriconian (Caer Caradoc series) are an
integral part of that system, and are not of Cambrian age ; neither
are the granitic rocks of Shropshire intrusive in the Uriconian.
As regards the relations between the Uriconian and Longmyndian,
he allowed that it was premature at that dato (January 1891) to'
assign a pre-Cambrian age to the Longmyndian, but he was disposed
to favour the idea of a break between it and the Uriconian, which
was essentially a volcanic formation, whilst the Longmyndians were
characterized by their even sedimentation. He thought that such
a chango of conditions must indicate a break in time, though the
unconformity need not necessarily be very great. Ho also took
the opportunity of pointing out that the occurrence of Malvernian
granites and schists in the Uriconian conglomerates indicates the
existence of an unconformity between the noncrystalline and the
1 Geol. Mag. 1893, p. 306.
2 Ibid. 1890, pp. 313, 314.
Digitized by Google
98 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 894,
volcanic scries. On this occasion, although Blake continued to
maintain his unconformable overlap, he does not appear to have had
any supporter. Dr. Hicks even went so far as to assert that the
Caer Caradoc volcanic group had constituted a source of supply for
the Longmynd series, in which there were no indications of volcanic
rocks. At that time he saw no reason for separating the Long-
mynds from tho Cambrian. It may be that he has modified his
opinion, since it has been shown that the Cowley Sandstone, which
is the associate of the quartzite, contains the oldest-known Cambrian
fauna, and must therefore be very near the base. This would seem
to leave but little room in the Cambrian system for the Longmynd
rocks, which may be regarded for the present as occupying a high
position in the Fundamental Rocks, somewhat analogous to those of
Howth and Bray Head, though not of necessity occupying precisely
the same horizon.
Onco more we find Prof. Blake busy with the unfossiliferous sedi-
mentary 8eries,and this time with the rocks mapped as Cambrian in
Caernarvonshire. In his first contribution to this very thorny sub-
ject, written some years ago, the Author alludes to the triangular
duel which had for some time been going on between Messrs. Hicks
and Hughes, as representing the most uncompromising pre-Cam-
brianism, of the one part, Prof. Bonney of the second part, and the
officers of the Survey, as defenders of Ramsay, of the third part.
Not that Prof. Hughes and Dr. Hicks have been at all times agreed
in their respective interpretations of this troublesome district, nor
that the officers of the Survey have undertaken to maintain the
vi»?w8 of Sir Andrew Ramsay in their entirety. The Author tells us
that he was led to study tho area from its relations to the rocks of
Anglesey, with tho result that the evidence on the ground is not
sufficient to justify the conclusion that pre-Cambrian rocks can be
said to occur, although, in his map, the igneous mass between Caer-
narvon and Bangor is represented as pre-Cambrian of two distinct
types. In his opinion the views of the Survey, except as regards
metaraorphism, most nearly approximated to the natural interpre-
tation of the facts that were known at the time, although new facts
now necessitate a modification.
He altogether disputed the notion of a basal Cambrian conglome-
rate in North Wales, alleging that in the Bangor and Caernarvon
area three different conglomerates had been confounded. He further
a11eg( d that the only conglomerate in tho district which showed
distinct unconformity upon the underlying rock was of Arenig age.
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 99
Whilst apparently regarding the great igneous mass between Caer-
narvon and Bangor as pro-Cumbrian, he held that the quartz-felsites
of Llyn Padarn and Moel Tryfaen are contemporaneous lava-flows
in the midst of the Cambrian series, the overlying conglomerates
being derived from them and from the sedimentary Cambrian rocks
to the westward. These views were supported by detailed sections.
It is worth while noticing that Prof. Blake still had faith in the
1 true basal Cambrian conglomerate ' in the St. David's district, since
the underlying beds in that area do not bear sufficient resemblance
to the series in North-west Caernarvonshire to admit of their
correlation.
This paper was presently followed by one from Miss Raisin on the
lower limit of the Cambrian series in North-west Caernarvonshire.
After discussing the position of the Bangor Beds, she allows that the
age of the northern beds must depend to a great extent upon the
classification adopted for the Llyn Padarn rocks, remarking that it
has recently been proposed to regard the quartz-felsitc of this dis-
trict as a lava-flow of Mid-Cambrian age, and tho beds to the north
as lower strata included in the same great series. It was very
clearly shown on this occasion that a part, at least, of the evidence
for the former view was based on a misapprehension, and the Author
pointed out other difficulties in accepting Prof. Blake's interpreta-
tion, viz. the enormous thickness of beds which must be cut out by
the supposed Arenig unconformity at Caernarvon ; the difficulty of
assigning two felsitc masses lithologically similar to two distinct
periods, and the occurrence of conglomerates similar to those which
are elsewhere admitted to be basal Cambrian.
Quite lately Prof. Blake has returned to the charge, having
favoured the Society with two papers containing an immense
amount of detailed stratigraphy in support of his general conten-
tion qs to tho absence of pre-Cambrian rocks in North-west Caer-
narvonshire. He now ventures upon a definite succession in his
Cambrians, commencing with the Pale or Green Slates, which have
attracted attention as lying at tho top of tho series in tho great
quarries of Penrhyn and Llanberis, and terminating with the
Brithdir quartz-felsite grit, which may or may not be a true base in
accordance with the age assigned to the Dinorwic felsite. A triple
subdivision is assigned to the entire scries, the highest including the
Purple Slates with some associated grits, the middle subdivision
consisting of Pale-banded Slates and Halleflintas, whilst the lowest
subdivision is made up of Laminated Grits and Conglomerates.
IOO PROCEEDINGS OF THK GE0L06ICAL SOCIETY. [May 1 894.
The general succession is argued to be the same in the isolated
portion south-cast of Bangor, as in the main mass. Not having
been able to make things fit in with the existing Surrey map, he
offers one of his own, which he does not bring forward as absolutely
correct ; doubts may affect the surface-distribution, but of the vertical
succession, he claims, there can be no doubt whatever. The presence
of the summit-beds of Blake's Cambrian would seem to depend on
whether the Bronllwyd Grit, which he regards as belonging to the
overlying group, rests conformably or unconformably on the under-
lying rocks. Amongst his conclusions he regarded it as proved that
the rocks to the west of the fclsite belong to the lower part of the
series, and those to the east to the upper, both being determined in
areas where the felsite is absent, and hence it appears probable that
the fclsite mass is a volcanic complex belonging to the middle of the
Cambrian period.
In his last paper 4 On the Felsites and Conglomerates between
Bethesda and lianllyfni/ Prof. Blake, in support of his previous
argument, asserts that tho felsites occur on so many horizons that
they could only be one mass if they were intrusive. He regards it
as having been abundantly shown that the conglomerates, derived
from these felsites — at all events on the east side of the faulted
Silurian strip— do not lie at the base of the Cambrian series. He
allows, however, that it is another thing to demonstrate that any
of them are of later age than the workable slates — and to this he
now limits himself. Such a contention cannot bo demonstrated
off-hand ; the proofs as to the relations of the conglomerates to the
felsites require, he says, a careful consideration of tho whole
obtainable evidence, and this is so interwoven that it is necessary
to take the localities in geographical order and exhaust the evidence
in each. Of course we cannot follow Prof. Blake, on the present
occasion, across country generally, but his reading of the Moel
Tryfaen section presents features of considerable novelty. He
evidently expects that this will give the coup de grdce to the idea of
pre- Cambrians occurring in this district. It is clear that previous
observers have been hasty in assuming that the great crags of con-
glomerate on the summit are really represented in the interior of that
mountain. For the first time we have something like a section as
afforded by the adit : the length is a little over a quarter of a mile ;
the average dip of the beds about 60°. The Author shows that,
next the Purple Slates, there is a conglomerate of quartz-pebbles in a
gritty green matrix, say 4 feet thick, and that all the rest consists
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. IOI
of a series of Banded Slates and Laminated Grits, with some inter-
calated bands of felsite or felsitic matter — this sequence being
unbroken until the great mass of felsite on the "west side is reached.
He correlates the adit conglomerate with the Rhiw-wen Grit of his
previous paper, and the rest of the sedimentary beds with the
middle and lower series of his Caernarvonshire Cambrians, after
making due allowance for local changes. There are at least four
bands of felsite in various parts of the series, clearly not intrusive,
and usually associated with tuffs ; whilst most of the grits are
obviously composed of their debris. They are not at all meta-
morphosed, but only cleaved. He further describes the outcrops
as generally corresponding to the indications in the section, and
argues that the conglomerate and grit on the summit have no
connexion with the thin quartz-conglomerate in the adit. As theso
have to be provided for, he suggests that they may possibly be an
extension of the Bronllwyd Grit and overlying rocks.
It can hardly be supposed that the great Cambrian controversy
in North-west Caernarvonshire has been definitely settled by the
series of papers to which I have just drawn your attention. We
perceive, it is true, that other gladiators have entered the arena,
and that the fight waxeth hotter even than before. But who can
tell what the end may be ; or rather, who shall attempt to estimate
the value of a name ? If we refer to page 83 of this Address, it
will be found that the green slates at the top of the Penrhyn quarry
contain that Conocoryphe viola which, we are told, must be included
in the lowest Cambrian. Thus we are at once brought to recognize
the fact that the lowest Cambrian of the palaeontologists forms the
summit of Prof. Blake's Cambrian. Hence there are two Cambrians,
a fossiliferous and an unfossiliferous series, which may indeed belong
to one system, though at present that must not be taken for granted.
Where there is any doubt we shall naturally be guided by palaeonto-
logy, since any other method of ascertaining the age of beds, except
where the stratigraphy is indisputable — and no one will say that of
North-west Caernarvonshire, — is liable to serious error. A point in
favour of Prof. Blake's viow is that the Penrhyn slates seem to
constitute one series, so much so that nobody would ever think of
separating the Upper Green Slates from the Purple Slates and associated
grits. The unfossiliferous beds then may be regarded as possibly
Cambrian — down to what line shall we say ? Here conies the
difficulty. The middle and lower subdivisions of Blake's Cambrian,
so far as one can judge by description, do not seem yery promising
vol. l. h
102 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
ground, such as might yield a fauna. Hence there is little to be
hoped from the possible discovery of fossils. So long, therefore, as
the matter has to be decided by stratigraphy, aided sometimes by
lithological considerations, the fight is apt to be prolonged.
Now, as regards the latter method, Prof. Bonney, we are told,
has often insisted on the slight degree of difference between some of
the later Pebidian and the earlier Cambrian rocks. This is the view-
that I have myself always maintained with regard to the beds in South
Wales. Consequently, where palaeontology, as at present, gives us
no clue and where lithological distinctions fail, if we wwh to draw
a line at all we are bound to fall back on stratigraphy. It rests,
then, with those who are desirous of establishing the existence of
pre-Cambrian rocks in North-west Caernarvonshire to draw tbat line.
Do they still believe in the existenco of a basal Cambrian conglome-
rate along the eastern margin of the great felsite mass which
terminates at Llanllyfni ? Prof. Blake alleges that conglomerates
and felsite9 are apt to wait upon each other without Bpecial refer-
ence to period, while Dr. Hicks but lately spoke of a pre-Cambrian
ridge in the neighbourhood of the Penrhyn slate-quarries, on both
sides of which the Cambrian succession is shown, the basal Cambrian
conglomerate being traceable on an irregular pre-Cambrian floor.
At this stage the controversy rests for the present. If an impartial
jury were empannelled and the evidence now available placed before
them, it is probable that they would take refuge from their perplexity
in a verdict of * Not Proven ' to each of the various contentions.
To this subdivision of the Fundamental Hocks also belongs Prof.
Lloyd Morgan's paper on the Pebidian volcanic series of St. David's,
which, for reasons already mentioned, I am precluded from noticing
on the present occasion. The clastic rocks of Charnwood Forest,
too, as decided in their recent paper by Messrs. Hill and Bonney,
are likewise referred to the latest epoch in the pre-Cambrian series —
the Pebidian.
The CnjstalHne Schists, etc. — The term Archcean is by some
restricted to the lower subdivision of the Fundamental Rocks. Be
this as it may, the Crystalline Schists and Gneisses are sufficiently
distinct from the rocks of the upper subdivision to be considered
under a separate section. Again, then, we seem bound to turn to
Messrs. Peach and Home's exhaustive memoir for an account not
only of the original types of Lewisian Gneiss, but also of the
subsequent changes which these have undergone. This subject has,
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT* 10$
however, been already dealt with by Sir A. Geikio in his first
Presidential Address. Perhaps one of the most valuable lessons
which a study of these rocks, and of the pre-Torridonian movements
by which they have been affected, conveys, is to be sought in the
evidence thus afforded that the foliation of eruptive rocks is one of
the possible and even probable modes of the formation of gneiss.
So thought Prof. Bertrand, after his recent visit to the North-west
Highlands, which he regards as a district that everyone must study
who wishes to comprehend such matters. At this view of the caso
British geologists are not likely to be surprised, since the history of
petrology for the last seven years yields abundant proof of the
change which has come over men's minds with reference to the
origin of foliated and schistose rocks.
There is no region, perhaps, where these views have received
stronger confirmation than in the limited yet classic region of the
Malverns. It will be convenient to consider the subject under the
heading * Fundamental Hocks/ since there can be little doubt that
the main mass of schistose crystalline rocks in this area may be
regarded as of Archscan age ; although it is just possible that some
of the rocks subsequently placed in the 1 Miscellaneous ' group
have as much title to bo considered Archaean as those of
Malvern. There havo been two principal competitors in this field,
viz., Mr. Rutley and Dr. Callaway, the former of whom has written
two and the latter three papers on the district. It is true that
Mr. Rutley has also contributed a third paper on Perlitic Felsitcs,
probably of Archa?an age,from the flanks of the Herefordshire Beacon ;
but as the main interest of this paper relates to decomposition-
products, chiefly epidote with possibly a little kaolin, which have
been formed within the minute fissures and perlitic cracks, it need
not further be quoted in reference to the possible origin of the
Malvern crystalline rocks.
Mr. Rutley broke ground some years ago with his duplicate paper
on the Metamorphio Rocks of the Malvern Hills. He first recited
the endeavours of Holl to demonstrate that the rocks which had
hitherto been regarded as * syenite ' and supposed to form the axis
of the hills wero in reality of metamorphic origin and pre-Cambrian
age. The Author restricted his observations to the old ridge of
gneissic 1 syenite/ granite, etc., which he considered might bo
divided into three series. The lower series, occupying the northern
part of the range, consists of coarsely crystalline gneissic rocks,
granite, * syenite/ etc. ; the middle series of gneissic, granitic,
h2
104 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1 894,
and 'sycnitic' rocks of medium and fine texture. The central
block of the range, from the Wych to the fault in Swinyard's Hill,
consists chiefly of the lower and upper middle series, but with a
portion of the lower series at the south end. The upper series
consists of mica-schist and finely crystalline gneiss. He had little
doubt that the fine-grained schists were sedimentary, as they even
contained beds of quartzite. He further discusses how far the
foliation of these rocks and their main divisional planes represent
original stratification, leaving this point an open question. He
observes that, in the Malverns, the strike of foliation is not parallel
to the axis of elevation. Although Mr. Rutley was inclined to
believe that the divisional planes may be planes of original stratifi-
cation, ho cannot say more than that they are original planes of
some sort, between which the rocks exhibit diverse lithological
characters.
In the second portion of his paper this Author gave the results of
the microscopic examination of these rocks, which tended to show
that those of a truly eruptive origin are more plentiful in the range
than he at first supposed. He admitted there was no reason to
believe that the alteration of any ordinary sedimentary rocks could
have resulted in such a vast amount of hornblende as is found in
these gneisses, and he suggested a pyroclastic origin for some of the
beds. It is evident that he could not free himself from the idea
that some at least of the structural planes in these rocks indicate
planes of stratification ; and that the foliation, in many cases if not
in all, denotes lamination due to deposition, either in water or on
land-surfaces, possibly accentuated by subsequent movements. We
plainly perceive that Mr. Rutley, at that time, regarded the main
mass as consisting of ordinary sediments metamorphosed into schists
and intruded upon after their formation by igneous masses. Although
he could not exactly make out the relations of foliation to sedimen-
tation, he felt sure that there had been deposition of some sort.
Nor has he very much altered that position in more recent years.
Speaking, for instance, when Dr. Callaway's second paper was read,
he allowed that a certain number of rocks were eruptive, although
he considered that a large portion consisted of the detritus of erup-
tive rocks, while towards the south they were mainly micaceous
schists and bedded quartzites, which he regarded as altered sedi-
ment aries. When Dr. Callaway's third paper was read, Mr. Rutley
went so far as to allow that the schists of the Malvern Hills had
been formed, to some extent, from plutonic rocks. This we must
Digitized by Google
Vol. 50.] AH5IYBB8ABT ADDRESS OF THE PRESIDENT* 10$
regard as a concession to modern opinion with reference to the
origin of many gneissic rocks, not only in the Malverns, but else-
where.
Turning now to the consideration of Dr. Callaway's triple
memoir on the Malvern Hills, we find that his first paper offers the
results of a preliminary enquiry into the genesis of the crystalline
schists. Dr. Callaway expressed his belief that many of the
Malvern schists had been formed out of igneous rocks, but he limited
his observations, in the present instance, to certain varieties, such
as diorite, granite, and felsite. The products of metamorphism
were divided into two groups. Simple schists are those derived
from the alteration of one kind of rock — thus, hornblende-gneiss
from diorite ; mica-gneiss from granite ; and mica-schist from felsite,
which latter rock is seen gradually to acquire a parallel structure.
Accompanying this mechanical alteration in the felsite is a mineral
change ; mica at first appears in very small quantity, either filling
cracks or accentuating the parallelism ; in a more advanced stage
the mica lies in imperfect folia, and sometimes forms a partial
coating to grains of quartz ; finally there is little left but quartz
and mica, the latter in folia and enveloping individual quartz-
granules. Injection- schists are those formed by the intrusion of
veins which had acquired parallelism by pressure ; this group being
afterwards subdivided into Schists of primary injection, in which
one rock was injected by another, and Schists of secondary injection,
formed by the infiltration of secondary minerals along shear-planes.
It was further noted that, in the majority of cases, particular
varieties of schist occurred in the vicinity of the igneous masses to
which they were most nearly related in mineral composition ; and
that the mineral banding of rocks in the field was more like voin-
structure than stratification. The metamorphism, he states, had
been brought about by lateral pressure, evidence of which was to
be seen in the intense contortion of granite-veins and in the effects
of crushing as observed under the microscope.
The conclusions to which the Author pointed in this paper were,
on the whole, well received ; and it may be said that the belief has
continued to gain ground that the Malvern rocks are mainly igneous
rocks rendered gneissoid from pressure. There may be a few ex-
ceptions, such as the rocks described as quartzite, and certain fine-
grained schists not obviously in connexion with igneous masses.
It is by no means clear, however, that the views so ingeniously put
forward in his two latest papers by Dr. Callaway will meet with
Digitized by Google
106 PBOCEEDUfOS OP THE GEOLOGICAL SOCIETY. [May 1894,
such general acceptance. These papers are too exclusively minera-
logies! to be noticed at any length on the present occasion, relating,
as they do, principally to the production of secondary minerals at
shear-zones, and discussing difficult problems in connexion with
change of substance on a large scale in rock-masses (metasomatosis).
The chief chemical and mineral changes, he says, have taken place
in bands of rock which have been subjected to a shearing movement,
so that the metamorphism may be described as « zonal/ The maxi-
mum of alteration has been produced in diorite where it has been
sheared in proximity to granite- veins. It is considered that contact
effects are here combined with dynamic metamorphism. Amongst
the most important chemical changes are the removal of bases and
the combination of potash with some of the constituents of diorite.
The chief mineral changes are stated to be the reconstruction of
felspar, and the production of biotite through chlorite from horn-
blende ; of white mica from orthoclaso, plagioclase, black mica, and
chlorite ; also of granular quartz, sphene, and actinolite. Dr. Cal-
laway is likewise prepared to go a long way in the direction of
wholesale substitution. The appearance of sedimentary rocks
towards the south end of the chain, so often urged by Mr. Butley,
is quite delusive ; all this is the result of more intense shearing.
The more highly quartzose the rock, the more intense has been the
metamorphism. Even a diorite may have all the bases squeezed or
dissolved out of it, and thus figure in the end as an acidic schist.
The gradual elimination of the magnesia, a necessary accompani-
ment of this operation, is one of the points to which attention is
drawn in the last paper. It would have been more to the purpose
if the Author could have shown us how to get rid of the alumina.
Reverting to the main question, I am not aware that there is any
good field-evidence as to the existence of shear-zones at all in this
region, though mere shear-planes, where the parallelism is more or
less accidental, are stated by Dr. Irving to be conspicuous structural
features of the rock-masses exposed to view in extensive quarries
at North Malvern and elsewhere.1 It has been hinted that the
crushed material in the so-called shear-zone at "West Malvern may
perhaps be a * friction breccia,' and the possibility of other supposed
zones being mere dislocations has also been indicated. Altogether
we must admit that Dr. Callaway, by his three papers in the
Quarterly Journal, has made a material contribution to our know-
ledge of the origin of the Malvern crystallines, besides having raised
1 GeoL Mag. 1892, p. 461,
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. IO7
some theoretical questions of extreme interest ; but it still remains
to be seen how far the methods which he suggests are precisely
those which have actually been in operation.
General Petrology.
In bidding farewell to the Archaean rocks we may be said to have
reached the base of the stratigraphical column, and at this point I
might, perhaps, have brought my address to a conclusion. There
remains, to be sure, a large amount of matter yet to be dealt with.
In addition to the papers relating more especially to the Funda-
mental Rocks — papers which are themselves largely based on
petrological considerations — we have had a number of communica-
tions in which petrology may be regarded as the chief factor.
Indoed, as the Fellows of the Society know very well, a 4 petrological
night ' has been no uncommon feature at our meetings for some years
past. These papers may roughly be divided into two primary
classes, according as they relate to the British Isles or to foreign
countries. In the former class are papers dealing with Scotland,
the Lake District, Wales, Devonshire, the Lizard, and, lastly, the
Channel Islands, including notices of Britanny. The papers on
foreign subjects relate to Switzerland and the Alps, and to countries
so distant as Brazil and New Zealand, besides a host of papers on
a variety of subjects ranging from Piedmontite-schist in Japan to
the Tudor specimen of Eozoon and the Dwindling and Disappearance
of Limestones. The total number of these petrological papers exceeds
sixty. In order to bring the present address within a reasonable
compass, I must limit my remarks to papers on the British Isles
and their immediate vicinity, and even in this case those papers
which are in the main petrographic or mineralogical will be
omitted. Of course it is obvious that, in dealing with a subject
which has so many technical issues, none but a specialist could
hope fully to grapple with the details. It is for this reason also
that; instead of basing the subdivisions on philosophical grounds,
I have adopted, as the more simple plan, a topographical arrange-
ment, although this has the disadvantage of mixing the subjects in
an inconvenient manner. The rocks considered under this heading
may be of any age from Archaean upwards.
Scotland. — There have been four papers by Prof. Judd, one by
Miss Gardiner, and three by the officers of the Survey.
Trof. Judd's first two papers, on the Tertiary Volcanoes and on
I08 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. l8°4»
the Propylites of the Western Isles, relate to matters which have
been more or less touched upon by Sir A. Geikie in his second
Presidential Address, and consequently I need not bring them
prominently forward on the present occasion. The second of these
papoVs was mainly written for the purpose of showing that the
* felstonos,' described by the Author in his first paper as const itoting
the oldest series of the Tertiary volcanic rocks of the Western
Isles, belong to that variety of the andesites known as propylites.
These rocks, when found in an unaltered state, present remarkable
analogies with the andesites of Iceland and the Faroe Islands,
whilst in the altered condition in which they usually occur the
propylites of Scotland resemble those of Eastern Europe and other
regions. A detailed description ensues, and the Author states that
these rocks exhibit every gradation in minute structure from holo-
crystalline forms (diorites) through various 1 granophyric ' types
into true vitreous rocks such as pi tens tones ; whilst, by carefully
following in the field tho much-altered rocks to points where they
retain some of their original characters, the propylites can be
shown to represent various interesting types of andesite and diorite.
The chief agent in producing change in these rocks he considers
to have been solfataric action, and this waa shown to have
accompanied the intrusion into the andesites of masses of igneous
material, acid in composition, such as granites and felsites.
Forming a very striking contrast with the older Tertiary
andesites (propylites) are the numerous scattered and generally
small masses of rock, which belong to a late epoch in the Tertiary
volcanic period, and constitute the youngest eruptive rocks of the
British Isles. One interesting example is afforded by the Scuir of
Eigg. These rocks have the mineralogical constitution of the
augite-andesites, but differ from the older series in the relative
proportion of crystalline and glassy constituents. Thus, holocrys-
talline aggregates of basic composition are found passing, as the
quantity of acid glass increases, through various phases until they
finally assume the vitrophyric form of pitchstone-porphyries. The
rocks of the Tertiary dykes in the South of Scotland and the North
of England were shown to agree with these later Tertiary andesites,
both in their mineralogical constitution and in the peculiar phases
which they exhibit.
In his paper on Composite Dykes in Arran, read at the close of
last session, Prof. Judd has further supplied us with valuable
information on this very subject, the analogues of the Arran dykes
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 1O0
being, as he observes, found likewise over an area extending from
Yorkshire on the east to Donegal on the west. He does not
hesitate to apply the term * volcanic ' to a series of infilled fissures,
whose subaerial products have been so insignificant that conspicu-
ous traces of them are only known to exist at a few points, such
as Ben Hiant in Ardnamurchan and the Scuir of Eigg. The
chief types of these late ejections are represented by a series of
rocks, such as the Cleveland dyke and similar eruptive masses,
ranging from augite-andesites to dolerites ; in these there is not
much glass, as a rule, but occasionally this may be present in such
quantity as to produce a pitchstone-porphyry. The other type of
rock is represented by the various * pitchstones ' of the Western Isles
of Scotland. These rocks are of much more acid composition than
the before-mentioned augite-andesites, and their silica-percentage
ranges from 65 to 75, the vitreous groundmass being usually in
excess ; by devitrification they pass into various forms of felsite
and quartz-felsite.
In the study of these dykes Prof. Judd considers that there is
abundant evidence of the process of differentiation of lavas. Those
of Arran are especially instructive, as affording proofs of the
re-opening of the fissure after its first injection and the introduction
of materials of a totally different composition. Hence the differ-
entiation in these cases must have taken place previously. One of
the most interesting examples of the union of the two types of late
Tertiary lavas, viz. the basic augite-andesite and the acid pitch-
stone, in a single dyke, occurs in the great mass of Tertiary granite
occupying the northern half of the Island of Arran. This is known
as the Cir Mhor dyke, which has a felsite-and-pitchstone centre,
whilst the sides are composed of a porphyritic augite-andesite, the
acid and basic rocks being always completely distinct, though
varying in relative width. They are also strongly contrasted with
each other, alike in the characters of all their porphyritic crystals
and of their vitreous bases. The acid rocks, however, contain a
few crystals evidently derived from the basic rock, which in this
case must have been the first to come up. The microscopical
characters of the rocks composing the Cir Mhor dyke are described
with considerable detail, and mention is also made of hyalite as a
constituent of the acid portion of the dyke.
On the shore and in the cliffs at Tormore, on the west coast of
Arran, there occurs a remarkable plexus of dykes, many of which,
according to Prof. Judd, supply striking illustrations of that class
Digitized by Google
110 PBOCEEDINGS OP THE 6E0L0GICAL SOCIETY* [May 1 894,
of composite dyke where the fissure has been reopened. In sorae
cases, he says, the acid rock was clearly introduced after the basic, in
others the order of ejection of the two materials was reversed. In
some instances the line of weakness, along which the opening and
re-injection of the dyke took place, lies towards the centre, at other
times it is at the side of the dyke, and occasionally it traverses the
dyke-mass in a sinuous manner. He consequently claims that the
interval between the first and second injection of these dykes must
have been sufficiently long to allow of the complete consolidation of
the older rock. As regards the respective ages of tho acid and
basic rocks in these dykes, if position has anything to do with
it, I would point out that, out of five diagrammatic plans of these
dykes or of portions of them, in every case, whether the containing
rock be granite or sandstone, the augite-andesite or basic material
is represented as lining the sides, whilst a centre of varying width
is occupied by quartz-felaite, pitchstone-porpbyry, pitchstone, dacite,
or some such rock.
In his summary, it will be observed that the Author especially
guards against any suggestion as to the accidental association of
the augite-andesite and 4 pitchstone ' in theso composite dykes
of Arran. All the facts, he says, point to the conclusion that the
fissures were injected from the same subterranean reservoir, but that
this reservoir contained two magmas of totally different chemical
composition. Rejecting in the case of the dykes of Arran the idea
of selective crystallization and liquation in the already injected
material, he says that we are compelled to fall back upon the riew
that an actual separation takes place amongst the materials of a
molten magma before the work of crystallization has commenced.
How this may have been effected has exercised the minds of experi-
mentalists and others for a long period of time.
Before quitting this part of Scotland I must draw your attention,
though very briefly, to another matter in connexion with then?
Tertiary volcanic rocks. Prof. Judd, who had the good fortune to
make some of the most remarkable discoveries in the Western Isle*
of Scotland which have been placed to the score of a British
geologist, has long been at issue, as you all well know, with an
equally distinguished authority as to the order of appearance of
certain Tertiary eruptives. Quite lately, in speaking of the fi«
great centres of volcanic outburst in the West of Scotland, Prof.
Judd again affirmed the sequence in time of the three kinds of
igneous material to have been, firstly the rocks of intermediate
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ill
composition (propylites), secondly the acid series, and thirdly tho
basic series. By way of incidental confirmation of the priority in
time of the acid over the basic series, he read a paper, about a year
ago, on Inclusions of Tertiary Granite in the Gabbro of the Cuillin
Hills in Sk ye. This kind of granite in its more central parts is de-
scribed as a true biotite-granite, but there is a constant tendency for
the biotite to be replaced wholly or in part by hornblende. When the
quantity of plagioclase increases in amount the rock passes into a
common granitite or hornblende-granitite. Towards the peripheral
portions of the intrusive masses a marked change takes place in tho
characters of the rock, the mica and hornblende are gradually
replaced by augite, magnetite becomes a prominent constituent,
whilst a remarkable drusy structure is developed. It is this variety
of rock which has been called granophyre, and it passes in turn into
ordinary quartz-felsite. The gabbros are typical, exhibiting every
gradation from augite-gabbro to common or diaUage-gabbro ; and
the monoclinic pyroxene is to a greater or less extent liable to be
replaced by bronzite or hypersthene.
Prof. Judd then proceeds to describe an interesting junction of
granitic rock with gabbro along a ridge, some 1000 feet above sea-
level, on the north-east side of the far-famed Loch Coruisk. At this
place inclusions of the granitic rock, sometimes haviug an area of
several square yards, are found to be completely enveloped in the
mass of the gabbro, which here exhibits all its ordinary characters.
Indeed, tho inclusions may be said to occur near to the line of one
of the largest and most typical junctions of gabbro and granite iu
the whole region.
Some doubt, in the course of the discussion on this paper, was
thrown on the actual relations of these acid fragments to the
encasing rock. But setting such doubts and others of a similar
nature aside, and admitting that the inclusions are portions of some
of the acid masses of the Tertiary volcanic series in the Hebrides,
the question arises as to whether the Author is entitled to say that
he has, in this way, brought forward any valid proof of the relative
ages of the basic and acid bosses of the West of Scotland. Sir
Archibald Geikie thinks not. That geologist referred to traces of
acid protrusions at an early part of the volcanic history of the
region, and suggested that the inclusions might belong to this early
series of acid rocks, of which only ejected fragments had yet been
found. He further alluded to a remarkable portion of the junction-
line between the granite and the gabbro, in the same neighbourhood
112
PROCEEDINGS OF THK GEOLOGICAL 80CIETT.
[May 1894,
as that where the inclusions are said to be found. At this place he
had on a former occasion described the occurrence of numerous veins
proceeding from the mass of granite there and traversing the gabbro,
and if these observations were correct they afforded a complete
demonstration that Prof. Judd had reversed the order of appearance
of the two rocks ; moreover, he considered that his own view of the
case received corroboration at many other localities in the Western
Isles. With reference to the case mentioned by Sir A. Oeikie in
the Cuillin Hills, Prof. Judd alleged that earlier writers had failed
to discover any veins proceeding from the granite into the gabbro.
whilst he had himself searched for such evidence without being able
to find anything of the kind. It is fortunate that we are not on the
present occasion called upon to decide on the merits of this case,
which, in its narrower issues, resolves itself very much into a
matter of field-geology. The general question as to whether the
great acid eruptions of the Hebrides preceded or succeeded the basic
ones is probably too large to be decided by the evidence of a single
locality. Indeed, when we have to deal, not with one, but with a
multiplicity of volcanic complexes, it is just possible that one section
may tell a story which another section contradicts.
Once more the venue shifts to the North-west Highlands — to the
mainland of Sutherland and Ross — and we are again led to consult
Messrs. Peach and Horne as to the igneous rocks in theTorridon and
Cambrian formations. These occur as intrusive masses on several
horizons. Tho famous Loch Borolan porphyry finds a place here,
and this rock may bo further studied in a recent contribution to the
Transactions of the Royal Society of Edinburgh 1 by Messrs. Horne
and TeaD, where those authors describe * Borolanite ' as an igneous
rock intrusive in the Cambrian Limestone of Assynt and theTorridon
Sandstone of Western Ross. The proofs of the intrusive nature of
these masses are said to be conclusive, more especially in the alter-
ation produced by them in the Led beg marbles. They have been
injected along the bedding-planes, and in some cases so regularly
that it was at one time thought they were contemporaneous lava-
flows. On the western face of Canisp a mass of porpbyritic felsite
rises from the old platform of Archaean gneiss, passing upwards into
the overlying Torridon Sandstone and eventually spreading along
the bedding-planes. Detailed mapping indicates the positions
occupied by these igneous masses throughout the Torridon and
Cambrian beds. It is considered that the outbreak of plutonic
1 Vol. zxxvii. (1691) part i. p. 163.
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. U3
activity in these ancient sedimentary systems must have been com-
paratively local. In the area lying to the west of the post-Cambrian
movements these igneous rocks extend over a distance of about 9
miles from north to south, but in the region affected by those
movements the distance is stated to be 24 miles. Originally they
must have penetrated far to the eastward, for they are carried in a
westerly direction with the associated sedimentary strata along the
higher thrust-planes, indicating that the period of activity to which
they belong is later than the Cambrian limestone of Durness and
earlier than the post-Cambrian movements.
With few exceptions the rocks intrusive in the limestones are
more basic than those in the quartzites, although hornblende-bearing
rocks are common to both series. The Loch Borolan porphyry is
described as an intrusive mass; the greater portion is highly
granitoid, the prevalent type in the west being a coarse granitic
rock consisting mainly of orthoclase with a little quartz, occasionally
porphyritic with some mica ; the Becond type, cast of Loch Borolan,
is characterized by dark garnets associated with orthoclase and a
blue mineral, and may be foliated or non-foliated. This, I presume,
is the rock described as * Borolanite,' a group especially characterized
by the association of orthoclase and melanite, and which naturally
falls into the elaeolite-syenite group, though in this case melanite is
raised to the rank of an essential constituent. The action of the
various intrusive masses and especially of the Loch Borolan porphyry
upon the limestones is highly interesting ; whilst the evidence of
their physical relations to each other is brought forward in such a
way as to leave little doubt that recognizable bands of Durness
limestone have been converted into marble such as that of Led beg
by contact with the eruptive rock.
It would be interesting to follow this subject further, more
especially when one remembers what has been written about the
Ledbeg marbles and the curious rocks associated with them, but
the claims of other papers must be recognized, and there are yet
three on Scottish matters, two of them relating more or less to the
subject of contact-metamorphism. Taking these in the order of
their appearance, the first is by Miss Gardiner on contact-alteration
near New Galloway. It is, in the main, a microscopic paper and
relates the changes produced in an alternatingseries of grits and shales
towards the north-east of a granite-mass known as the Cnirnsmore
of Fleet. The Author notices the extreme variation in the degree
of alteration undergone in different places at the same distance
Digitized by Google
114 PROCEEDIXGS OP THE GEOLOGICAL SOCIETY. [May I 894.
from the granite, as for instance where grits are highly altered and
shales but little affected. This certainly is just the reverse of what
we should expect, unless the word * grit ' in this case implies some-
thing more than an assemblage of quartz-grains. She was, on the
whole, disposed to believe that the variation in the amount of altera-
tion at the same distances, the mode of alteration of the grits, and
the transference of material might be accounted for by the passage
of highly heated waters, and it was to the action of these that she
mainly attributed the contact effect. It is just possible that this
view may receive some countenance from the observation of Prof.
Brogger that the chemical nature of the intrusive rock does, in
certain cases, produce an influence on the character of the meta-
morphism. It is not easy to perceive how this could happen other-
wise than through the convection of solvents. Mr. Barrow believes
that Miss Gardiner's investigations have an important bearing on
the origin of the crystallization of the Highland schists.
We have now to consider two papers, contributed by officers of
the 8urvey, dealing with the subject of certain igneous rocks io the
schists of the Highland border. The first of these, by Messrs. Dakyns
and Teall, on the Plutonic Bocks of Garabal Hill and Meall Breae,
is devoted to the description of some rocks which occur in a complex
forming a belt of high ground almost immediately to the west of
the lower end of Glonfalloch, on the confines of the counties of
Perth, Argyll, and Dumbarton. These rocks are stated to vary
considerably in chemical and mineralogical composition, and, although
gradual passages are found between more or less acid varieties, in
other cases the junction is sharply defined. The more acid are
always found to out through the less acid rocks, when the two are
found in juxtaposition, and the fragments occurring in a rock are
observed to be less acid than the rock itself. Although thus shown
to be of different ages, they must clearly be referred to one geological
period. This period was not defined by the Authors, but, to judge
from the remarks of Mr. Barrow, the igneous mass is probably older
than the Old Red Conglomerate, yet more recent than the general
metamorphism of the Central Highlands. Basic rocks, mainly of the
diorite type, but containing two notable bodies of peridotite, form a
sort of fringe on the south-east side of the mass, which is, in this
direction, considerably mixed up with the country schist owing to
faulting ; next comes an area of tonalite and non-porphyritic granite,
and lastly, on the west side, a relatively largo area of porphyritic
granite of ordinary structure ; in one locality only a gneissose struc-
ture may be observed, the planes of foliation curving round included
Digitized by Google
Vol. 50.] AtfSIVEBSABT ADDRES8 OF THE PRESIDENT. X 1 5
fragments. Since there is no evidence of any portion of the plntonic
rock having been affected by earth-movements, in this case the
Authors are disposed to attribute foliation to movements anterior
to final consolidation.
The Authors conclude that in this area is the record of a series of
events connected with the consolidation of a vast subterranean
reservoir of molten rock, and the nature of the resulting complex
they proceed to describe. The first rocks to be formed were pcrido-
tites ; then followed diorito, tonalite, granite, and eurite (felsite)
in order of increasing acidity. The most acid rock known occurs in
narrow veins in the granite and tonalite, and is almost entirely
devoid of ferro-magnesian constituents. Probably Mr. Barrow-
would suggest that this last rock represented the remains of the
mother-liquor in which the granite, etc., had consolidated. The
Authors further describe the physical features of many of the rocks,
giving at the same time a detailed account of the constituent minerals.
A comparison of the general distribution of these shows that, in
this area (where it so happens that ordinary gabbros are absent),
in proportion as the olivine dies out pyroxenes increase in importance,
and these, in turn, are replaced by hornblende and biotite. Next
the hornblende decreases relatively to the biotite, and finally, in the
eurite-veins, the ferro-magnesian silicates have ontircly disappeared.
Turning to the quartzo-felspathic constituents and considering their
distribution in the same way, it is observed that plagioclase first
makes its appearance, then follows orthoclase and lastly microcline ;
quartz comes in with the orthoclase. It is instructive, they say, to
note that when the minerals pyroxene, hornblende, biotite, plagio-
clase, microcline, and quartz make their first appearance, they play
the role of groundmass ; in other words, they are allotriomorphic or
ophitic with respect to the other constituents. It is only when a
mineral has established itself as an important constituent that it
begins to show traces of idiomorphism. Thus in the order of for-
mation of minerals a certain amount of overlapping takes place, and
this overlapping is stated to reach its maximum in the pi u tonic
rooks. The following order of occurrence, deduced from these
investigations, accords on the whole with previous experience : —
Iron-ores, olivine, pyroxene, hornblende, biotite, plagioclase, ortho-
clase, microcline, and quartz. Accessory minerals are singularly
absent in the ultra-basic rocks.
Much attention has been paid by the Authors to the chemical
composition of these rocks, and very interesting generalizations thus
deduced. In accordance with precedent, a kind of chemico-minera-
Digitized by Google
1 1 6 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1804,
logical scale is suggested, where we may imagine absolute basicity to
be represented at one end by magnetite, and absolute acidity at the
other end by free silica. The scale actually presented to us by
Messrs. Dakyns and Teall, for the illustration of this particular group
of rocks, does not reach the extreme possibilities at either end,
though the range is very considerable. In the case now before us, it
is found that, as the silica increases in a rock, magnesia — after iron-
ores the most basic oxide— falls from a high position in the peridotites
to almost nothing in the eurite-veins. Out of seven kinds of rocks
selected to show the chemical sequence there is only a slight devia-
tion from this law in one instance. Lime first rises and then falls,
attaining its maximum in the biotite-diorite ; after the fall has set
in, it acts in sympathy with magnesia, whilst the iron -oxides follow
suit. Alumina rises rather rapidly from a low position in tbe
peridotites to a nearly level position in the diorites and granitites,
falling somewhat in the eurite vein-rock. Of the alkalies, soda
continues to rise for the most part, but with a somewhat marked
fall in the eurite vein-rock. Potash rises throughout the series,
except at the point where, as previously stated, there is a slight
check in the otherwise uuiform descent of magnesia. In the eurite
vein-rock, which here represents the acidic termination of the
sequence, potash is three or four times in excess of soda.
That somewhat similar views to those put forward by Dakyns
and Teall are entertained by other petrologists may be perceived
from a recent paper on the Basic Eruptive Rocks of Gran, in Xorwsy,
by Prof. Brogger. That Author confirms statements previously
expressed to the effect that the different masses of eruptive rock,
which occur within the sunken tract of country between Lake
Mjbsen and the Langesundsfjord, are genetically connected and have
succeeded each other in regular order. In this particular case the
oldest rocks are said to bo the most basic, and the youngest (with
immaterial exceptions) the most acid, whilst between the two
extremes Prof. Brogger has found a continuous series. Several
bosses of basic plutonic rock lie along a north-and-south fissure-line :
the prevailing form is a medium or coarse-grained olivine-gabbro*
diabase; but pyroxenites, hornblendites, camptonites, labrador-
porphyrites, and augite-diorites also occur. Analyses of the typical
rocks from three localities on the north-and-south line are given,
and the conclusion is reached that the average basicity of the rocks
forming different bosses decreases from north to south.
Of course, it is easy to see that the two cases are not exactly
Digitized by Google
Vol.50.] ANNIVERSARY. ADDRESS OF TUX PRESIDENT. II7
parallel, since iu the Norwegian case the rocks are all more or less
basic, nor do we know the amount of field-evidence on which the
genetic connexion between these several bosses is established.
With regard to the rocks on the west side of Glenfalloch, we
seem to have an assurance that such a sequence as the Authors have
narrated actually exists within the area in question, and conse-
quently that tho important deductions which follow do not wholly
depend upon penological considerations. It is all very well to
determine the order of crystallization of minorals in tho cabinet,
but if this philosophy is to be applied to large areas the evidence in
the field must be above suspicion.
Very much the same views, as to the effects resulting from the
order of crystallization, are expressed by Mr. Harrow in his paper
on an Intrusion of Muscovite-biotite Gneiss in the South-eastern
Highlands. The normal condition of the intrusive rock is that of a
slightly foliated granite with two micas. The masses observed
vary in size, and the larger ones are more or less fringed with
pegmatite - veins, which cut the metamorphic schists in every
direction, tho foliation in the larger masses being rudely parallel to
that of the surrounding schists. In tho north-western portion of
the area the intrusive rock is always a gneiss, and occurs in thin
tongues which permeate the surrounding rocks. Towards the south-
east these tongues amalgamate, and form large masses in which the
foliation is less marked. Whero the rock is a gneiss, it is composed
of oligoclase, muscovite, biotite, and quartz, but contains no
microcline. As the gneissic character becomes less marked, the
oligoclaso diminishes in amount, and microcline begins to appear,
especially towards the margin of tho masses, and in the most
south-easterly of these microcline is greatly in excess of oligoclase.
The differences in structure and composition are believed by the
Author to be due to the straining off of the crystals of earlier
consolidation during intrusion under great pressure. The still
liquid potash-bearing portion of tho magma was squeezed out and
forced into every plane of weakness in the surrounding rocks ;
and that portion of it which contained tho highest percentage of
potash finally consolidated as pegmatite.
The phenomena of thermo-metamorphism, accompanying this
intrusion of plutonic rock, are next considered. The rocks into
which these igneous masses have been intruded are in a highly
crystalline condition, and their grain is coarse, the micas being
especially of large size. The general aspect of the north-western
vol. l. *
Digitized by Google
1 1 8 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1894,
portion of the district is gnoissose, but as we proceed in a south-
easterly direction towards the Highland border the rocks become
finer in grain and more like the ordinary schists, finally assuming
the phase of phyllites and of more or less crystalline arkose grits.
This variation in the character of the rocks is accompanied by a
change of the constituent minerals, more especially the aluminous
silicates. It has been observed, for instance, that sillimanite,
cyanite, and staurolite characterize three more or less distinct zones,
which seem to be dependent on relative proximity to the igneous
masses, since the zones do not necessarily coincide with the strike
of the rocks. Thus, a thin bed of quartzite, which retains its
character in consequence of the simplicity of its chemical com-
position, may be followed through all the zones, whereas the bed
adjacent to it is : — in the outer zone a staurolite-schist, in the
intermediate zone a cyanite-gneiss, and near the contact with the
igneous rock a coarse silliraanite-gneiss. With regard to the two
latter minerals, both of which have essentially the composition of
andalusito, it may well be that the accession of heat alone, as
pointed out by Mr. Teall, would be likely to convert cyanite into
sillimanite, and thus the line separating these two minerals in that
area might, to a certain extent, be regarded as an isothermal.
With respect tc staurolite, the Author allows that the zone of this
mineral very nearly corresponds with the actual outcrop of a
particular bed. In this case the original composition of the rock
may have had something to do with its development. On in-
specting the map which accompanies this paper, one cannot fail to
observe that those three zones present a marked parallelism with
the great mass of ' newer granite ' on the confines of the counties
of Forfar and Aberdeen ; but the Author is of opinion that the
metamorphism produced by these later granites can be easily
distinguished from that which he has described, its effect having
been to destroy many of the characters due to the earlier action.
Mr. Barrow considers that the sedimentary character of the rocks,
as a whole, is established by their chemical composition. Lime-
stones, shales, quartzites, and coarse grits may all be recognized in
the metamorphic area. The lowest rocks, the quartzites of the
North Esk Valley, are highly siliceous, though containing a certain
amount of felspar, which both in the grits and gneisses is stated to
be almost exclusively oligoclase. Even of those rocks whose origin
may bo regarded as more obscure there is nothing, ho says, to
mggest that they have been formed of crushed igneous material.
Digitized by G(
Yol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. II9
This may be so, yet the large amount of alkali which analysis
reveals in such rocks as the phyllite and staurolite-schist would
seem to indicate that, even if fragmcntal, the materials had not
been leached to any extent. There is certainly something curious
in the composition of these two rocks. The intensity of the meta-
morphism he considers to have been due to the great depth to which
the rocks had been lowered when affected by the intrusion, and he
thus explains the occurrence of sillimanite and coarsely crystalline
gneisses, concluding that the special features noticed may have
resulted from action at great depths rather than from any physical
conditions duo to early geological time. If there is a certain
amount of speculation in Mr. Barrow's paper, it may, perhaps, be
justified by the uncertainty which yet overhangs the Dalradian
schists and all that they contain.
The Lake District. — An important communication by Messrs.
Harker and Marr on the Shap Granite and tho associated igneous
and metamorphic rocks again raises tho question of contact- or
thcrmo-metamorphi8m in another part of tho country and under
conditions which, though more limited in extent than the district
about Glen Clova described by Mr. Barrow, are, perhaps, on the
whole, loss difficult of interpretation. Thus, for, instance, the date
of the intrusion of the Shap granito can be fixed as having taken
place after the deposition of the Lower Ludlow rocks and before
that of the basal Carboniferous Conglomerate. The aureole of rocks
affected has a width of about three-quarters of a mile measured
from the granite-mass, and this width is pretty nearly tho same for
all the rocks invaded. But although there is, within this range, a
progressive metamorphism, nothing like distinct rings or zones can
be made out in the Shap Fell district.
Before considering the main subject of this elaborate paper, viz.
the contact-metamorphism of the surrounding rocks, it will be con-
venient to notice what the Authors say about the granite itself, and
also about certain dykes and sills in their relations to it. The Shap
granite is less acid than tho Skiddaw and Eskdale granites, whilst
the soda and potash are almost exactly equal in the bulk analysis.
On tho other hand, the orthoclase of the first consolidation, which
gives to the rock its well-known porphyritic appearance, contains 5
times as much potash as soda. It follows from this that the ground-
mass of the Shap granite is considerably richer in soda than in
potash. Mineralogical and petrographic details are given, and
120 PROCEEDINGS OP THB GEOLOGICAL SOCIETY. [May i8q4-
among other noteworthy features they record the abundant occur-
rence of andalusite, in idiomorphic crystals, usually coated with
little flakes of yellowish- or greenish-brown mica.
The study of the adjacent dykes and sills has led to some yen'
interesting conclusions. Viewed as a whole, the neighbouring
intrusions, while they have characters which seem to connect them,
on the one hand, with the Shap Fell granite, and particularly with
its darker patches, are unmistakably linked with the normal type
of mica-traps found at greater distances. None of the various
intrusions alluded to can be traced as continuous with the granite
at the present surface, and the Authors suggest that, if they are
light in regarding them as apophyses, these are in connexion, not
with the visible granite-mass, but with a deep-seated extension of
it. When these apophyses are considered in conjunction with the
patches of darker rock caught up in the granite, they appear to
throw light upon several of the dykes penetrating the Lower Palaeo-
zoic rocks of the district, which abound within a radius of 15 miles
of the Shap granite. Numerous dykes, it is true, are found round
the other granite areas of the Lake District, but these are usually
felsitic, whilst the dykes more immediately in the neighbourhood of
the Shap granite consist both of felsites and mica-traps — the latter
chiefly on the east side, and especially in the region between Shap,
Eendal, and Sedbergh. In the neighbourhood of the Shap granite
both the felsitic and micaceous dykes have abundant porpbyritic
felspars, which imply a relationship to the granite itself, and such
felspars arc found to become rare at a distance from that outburst.
As explanatory of these and other facts the Authors suggest that a
magma occurred beneath the Shap granite of more basic character
than the granite itself, and that from this the micaceous dykes*
were sent out, whilst some of this basic material also was carried up
as * clots ' in the fluid granite. These, it is presumed, constitute the
dark patches which attracted the attention of the late J. A. Phillip
and other observers.
The nature of the Shap intrusion is further discussed, and it i.«
argued that the abnormal alteration of the rocks around a mas?
with so small a diameter would suggest the passage of molten
matter for a considerable period through the channel which is now
filled with granite. In all probability such molten matter was for
a long time forced from the underlying magma through this channel,
though whether it terminated in a laccolite or in a volcanic out-
burst there is no present evidence to show. The rocks seen to be
in contact with this old pipe are the Brathay Flags and other division.*
Digitized by Google
Vol. 50. J ANNI VERS ART ADDRESS OF THE PRESIDENT. 121
of the Upper Silurian, whilst the Coniston Limestone completes
the sedimentary scries. Tho volcanic rocks in contact belong to the
upper part of the * Borrowdale Series ' and are represented by the
rhyolitic and andesitic groups ; the rocks on the north of the granite
being subsequently described as basic andesites.
Thermo-metamorphism in andesitic rocks has hitherto, Messrs.
Harkcr and Marr say, received but little attention, although Prof. Judd
has adverted to some changes of this kind in the andesites or
4 propylites ' of the Western Isles of Scotland. Tho andesitic group
is in contact with the Shap granite round one half of its circumference,
and the andesitic lavas are stated to afford sorao of the most instructive
examples of thermo-metamorphism in the district, tho process of
transformation being traceable in all its stages. What those pro-
cesses are can bo gathered only from a careful perusal of the paper
itself. Tho production of biotite, hornblende, and augite is narrated
with especial precision, and in addition to these the following
minerals of metamorphic origin are quoted from tho andesites and
andesitic ashes, viz. quartz, orthoclase, several kinds of plagioolase,
colourless mica (muscovite), sphene, apatite, magnetite, and pyrites.
The mctamorphisra of the rhyolitic rocks, of the Coniston Limc-
tone series, and of the Silurian rocks is very fully treated ; but it
will be sufficient on the present occasion to notice one or two points
only with reference to the mctamorphism of the Shap Fell rocks
generally. Thus, in estimating facilities for contact-metamorphism
in different rocks, it is observed that the substances resulting from
the 4 weathering 1 of the rocks were more susceptible to change
than minerals of direct igneous origin, and, as may be readily
supposed, the original quartz-sand in the flags proved especially re-
fractory. The several minerals detected in the various metamor-
phosed rocks, as products of the motamorphism, are summarized in a
table. Tho absence or rarity of some characteristic 4 contact-
minerals * of other districts is rather striking. Some of these, they
say, are products which probably require special * mineralizing
agents,' such as the compounds containing fluorine ; but the almost
complete absence of andalusito (chiastolite), staurolite, and garnets
(other than lime-garnets in connexion with the Coniston Limestone)
is certainly remarkable. This view of the case is somewhat modified
in tho list of metamorphic minerals appended to their second paper;
since andalusite, cyanite, and sillimanito are all quoted from the
metamorphosed acid lavas and ashes, though possibly these are ex-
ceptional instances which serve to prove the general rule.
In their Supplementary Notes on tho metamorphic rocks round
122
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
[May 1894^
the Shap granite, these Authors state they have since learnt that
basic lavas are very widely distributed ovor the Lake District, and
that the rocks on the north side of the intrusion must bo placed in
this division. Such rocks might with propriety be termed basalts,
although, on account of the absence of olivine, some petrographers
would prefer to call them basic andesites. The Authors again refer
to the action of ' weatheriug ' in connexion with this group, where
some secondary products have remained as pseudomorphs of the
minerals which generated them, while others, more soluble, have
become disseminated through the mass of tho rock, and especially
collected in small fissures and in the vesicles with which the lavas
abound. The basic lava of Low Fell contains 51 per cent, of silica
as against 60 per cent, in the ordinary andesite, but nearly 3 times
the amount of lime. Accordingly in the metamorphosed rock we
find green hornblende more common than mica in the mass as well
as in the contents of the vesicles. The ashes associated with the
basic lavas, however, contain brown mica far more abundantly than
hornblende, and the reason for this is seen iu their low percentage
of lime. Another principal difference is noticed in the abundance of
epidote. Special attention is also devoted to the metamorphism of
the infilled vesicles, and some important deductions are drawn irom
the phenomena observed.
After touching on some other points, the Authors conclude by
stating their belief that thermo-metamorphism is not accompanied
in general by any change in the chemical composition of the rocks
affected. The exceptions arc the partial loss of water and the
expulsion, under certain conditions, of carbonic acid. In some
districts it might be necossary to allow for the introduction of boric
and hydrofluoric acids, but that does not apply here. Innumerable
facts, they say, point to the conclusion that no transference of
material has taken place except between closely adjacent points, and
they are led to enquire what is the radius of the sphero of influence.
This must to a certain extent vary according to the nature of the
substance, and wc must expect to find it greater at higher tempera-
tures. As a test-case, they take the production of lime-silicates at
the expense of calcite, and conclude that somewhere about Jjj inch
would indicate the distance to which the interchange of lime and
silica has demonstrably taken place. Tho impression produced by
the study of other metamorphic minerals is in general accord with
tho above conclusion. Moreover, the dependence of the range
of transfer of material upon temperature is well illustrated in the
Digitized by G(
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. I 23
case of the calcareous ashes of the Shap district, since, on the outer
edge of the metamorphic aureole, it is only the most finely-divided
calcite which has been decomposed.
In addition to the ahove, the Lake District has yielded three
short papers which relate to the Skiddaw region. The first of these,
by Mr. Groom, is on a tachylyte associated with the gabbro of
Carrock Fell, and occurring in a vein about one inch thick. The
rock to which the Carrock Fell tachylyte most nearly approaches
appears to be the typical variolite of the Durance. It agrees with
this rock in the nature and behaviour of the varioles (spherulites),
in the character of the pyroxene-granules, and in the presence of
a green groundmass. The tachylyte is regarded as of Ordovician
age.
Mr. Postlethwaite has contributed two papers, which relate to
eruptive rocks on the north-west side of Skiddaw. In Hauso Gill,
which lies nearly due north of the summit of that mountain, are
two small exposures of a 'dioritic picrite' about £ mile apart,
though probably forming one mass. This rock is described as being
of a dark olive-green colour, and consisting of several varieties of
hornblende with some felspar, serpentine, calcite, and other mine-
rals. The Author remarks that it is still more remote from a
typical picrite than the Little Knott rock, at no great distance, and
it may be regarded as one of the transitional forms between normal
picrite and normal diorite. He intimates that these eruptives may
all have been derived from the same magma, since the differences
are little more than have been shown to exist between different por-
tions of the exposuro at Little Knott itself. The chief interest in
Mr. Postlethwaitc's second paper centres in a comparison instituted
between a sheet of diabase, intrusive in the Skiddaw series near
Bassenthwaite, and a parallel bed of fine-grained grit. Half a
century ago a considerable quantity of antimony was obtained from
the locality. From the attendant circumstances ho concludes that
the deposition of the metalliferous vein-stuff has been the result of
thermal action following the intrusion of the diabase.
Wales. — With respect to the Principality, there have been papers
by Mr. Harker, Messrs. Cole and Jennings, and Prof. Lloyd Morgan,
dealing with subjects which have been more or less touched upon by
Sir Archibald Geikie in his first Presidential Address. On the
present occasion we have to consider two papers by Miss Raisin
and one by Messrs. Jennings and Williams.
I
1
I
124 PB0CKKD1>08 OF THE GEOLOGICAL SOCIETY. [May 1 894,
The first of Miss Raisin's papers relates to the Nodular Felstone*
of the Lleyn. Not far from Afonwen Junction, on the south coast
of this extreme promontory of Caernarvonshire, is a mass of igneous
rock marked on the Geological Survey map * Felspar-porphyry
(intrusive) with agate-nodules.' The Author considers that the
character of the rocks clearly negatives the theory of intrusion;
they are old lava-flows, once glassy, now devitrified, and at Pen-y-
chain are associated with interbedded agglomeratic and ashy strata.
The mass of felstone near Pwllheli also contains similar nodular
inclusions. These rocks must be classed as pctrosiliceous, many
structures being probably duo to secondary devitrification. Every-
thing, says Miss Raisin, points to subsequent silicification with
attendant radialization in some cases. She suggests the percolation
of heated waters carrying silica in connexion with the declining
vulcanicity or solfatara-stage of the district.
These so-called * agate-nodules ' have long ago attracted attention.
The large spherulites seem to havo been developed either along
certain strata or within masses of flow-brecciation, those near to-
gether being fairly equal in size. The spherulite seoms to be the
most durable part of the rock, which usually exhibits an originally
vesicular character. The matrix surrounding the nodular spheru-
lites consists for the most part of what must have been a compact,
laminated, glassy lava, now devitrified, generally perlitic, and often
spherulitic. The interior of the nodule is in many cases filled with
chalcedony, and is not distinguishable in form from an original
vesicle of the lava. These nodular structures are classed under the
following groups :— contraction-spheroids, or magnified perlitic
structure ; masses resulting from flow-brccciation ; solid spherulites
or pyromerides; agate-nodules with an outer spherulitic crust:
quartzose amygdaloids ; and lastly spheroidal formations developed
round a nucleus, such as an agate-nodule, a group of crystals, or an
original vesicle of the lava.
With regard to the second of Miss Raisin's papers, I would
remark that the subject of Variolite has latterly assumed consider-
able interest and importance amongst British geologists, both from
the fact that this remarkable rock has been discovered at more than
one point in the United Kingdom, and also because it has formed
tho basis of some important communications to the Society. A very
brief allusion to two papers relating to foreign localities may not be
altogether out of place in this connexion.
Thus, in their paper on the Variolitic Rocks of Mont Genevre,
Digitized by GoogK
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. 1 25
Messrs. Cole and Gregory tell us that the variolito of the Durance
occurs in situ as a selvage on the surface of certain diabases, also
■is blocks in the associated fragmental rocks which are apparently
tuffs, and occasionally as a selvage to diabase-dykes. This product
of rapid cooling was originally a spherulitic tachylyte, and has
become devi trifled by slow secondary action. In fact, they say that
variolite stands in the same relation to basic lavas as pyromeride
does to those of an acid character. These eruptive rocks are
probably of post-Carboniferous age, and there are several other
areas of similar variolitic rocks both in the Alps and the Apennines.
The best modern representative of the conditions that produced
such rocks is to be found in tho great volcanoes of Hawaii.
In the succeeding volume of the Quarterly Journal Mr. Gregory
gave the results of his examination of the variolitic diabase of the
Fichtclgebirge as deduced from the neighbourhood of Berneck. This,
he concludes, is intrusive into rocks of Devonian age. The variolitic
structure is found to occur in two different arrangements, viz. : —
on the surface of spheroidal masses of compact diabase ; and, secondly,
as a true contact-product on the selvage of the diabase, the varioles
being true spherulites. He also concluded that, although the
varioles aro tho product of rapid cooling, too sudden a solidification
of the diabase may prevent their formation.
Returning now to the consideration of Miss Raisin's paper on the
Variolite of the Lleyn, it would appear that the first discovery of
this rock in Britain was made by Prof. Blake at Careg Gwladys in
Anglesey, as announced at the meeting of the British Association in
1888.1 Subsequently Prof. Cole described a rock of this description
from Annalong, in the county Down.2 According to the statement
of Prof. Bonneyt Miss Raisins discovery of Variolite at the Lleyn
affords the third example of this kind of rock in the British Isles.
The specimens described by that lady occur at Aberdaron, and also
ut one or two localities on the west coast of the Lleyn in a district
which was marked on the Survey Map as 1 Metamorphosed Cam-
brian.' Amongst tho rock-specimens not hitherto described, Miss
Raisin includes forms of variolite, a spherulitic, somewhat basic
rock. Tho igneous masses which contain these are stated to belong
to the class of rather basic andesites, or not very basic basalts :
corresponding to these two types of rock arc two forms of variolite.
Their general microscopic structure and development are described
1 Brit Assoc. Rep. 1833 (Bath Meeting), p. 411, pi. t. fig. 22.
2 Sci. Proc. Roy. Dub. Soc. vol. vii. (1892) p. 513.
126 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1894.
with considerable detail, the Author observing that variolite ba>
oeen defined as a * devitrified spherulitic tachylyte, typically ooane
in structure,' though she is disposed to place her own interpretation
upon the last phrase. The phenomena observed correspond in many
respects with those of the Durance and the Fichtelgebirge, as noted
by the Authors quoted on the preceding page. As regards the age
and associations of these variolite-bearing rocks of the Lleyn, there
are volcanic rocks including lava-flows, and fragmental masses
both of fine ash and coarse agglomerate. These are found in com-
pany with limestones, grits, and other rocks, which are possibly
of sedimentary origin. Without suggesting any particular agf.
Miss Raisin considers these variolite-bearing rocks to be of high
antiquity.
The neighbourhood of Ffestiniog is so well known to tourists
and especially to artists, from the picturosqueness of its scenery,
that somo account of its geological structure might seem to posses*
a popular as well as a scientific interest. The paper by Messrs.
Jennings and Williams on Manod and the Moclwyns is a contri-
bution in this direction. The area described by these Author*
forms part of the northorn ring of the Merionethshire anticlinal : the
Upper Cambrian strata dip under the mountains which give the title
to this paper, and are there overlain by ashes and slates of Arenig
age. Apart from the palscontological and stratigraphical evidence
offered by the Authors with respect to the Lower Palaeozoic rocks of
this district, they show the intrusive nature of the great crystalline
mass known as the syenite or granitite of Tan-y-Orisiau, and to its
intrusion they attribute the metamorphism of the surrounding
rocks. This, then, is another case of contact-metamorphism, though
it does not appear that any of the characteristic minerals are
largely developed. Round the junctions the sedimentary rock 1*
altered into a compact hornfeh, and in some places it is very diffi-
cult to distinguish the altered rock from the finely crystalline edge of
the granitite. Judging from the map which illustrates this paper,
the surface-exposure of the granitite lies wholly within Tremadoc
rocks ; but, in spite of what the Authors call the intensity of the
metamorphism, there is a striking absence of distinct crystals. The
brown mica so common in areas of contact-alteration is absent
throughout. In some cases, where spots are developed, these have a
tendency to quadrilateral form, and may, in the Authors' opinion, be
embryo crystals of andalusite ; but there is nothing resembling
rocks of the altered region about Skiddaw. This deficiency may be
Digitized by GoogI
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. 12 J
due, amongst other possible causes, to the original nature of the
containing rocks, of which, they say, it is difficult to speak with
certainty. An alternative but less probable supposition is, that it
may in part have been due to some peculiarity in the nature of the
intrusive rock. This is an acid granite with potash considerably in
excess of soda, very poor in ferro-magnesian silicates and abounding
in quartz. It has been subjected to considerable strain and
crushing, a circumstance which has suggested a comparison with
the rock of Bryn-y-Garn near St. Davids. An analysis of this
granitite compared with that of the eurite of Cader Idris shows
that this is slightly the more acid rock of the two, whilst the pro-
portion of the alkalies is nearly reversed.
Devonshire. — About half a dozen papers relate more or less to
petrological questions connected with this county, but as those
especially dealing with the volcanic history of the region have
already been noticed, it would be superfluous to allude to such
matters again. In his paper on the elvans and volcanic rocks of
Dartmoor, Mr. Worth has described two elvanito- dykes in the
neighbourhood of Tavistock for the purposo of demonstrating the
structural changes which they exhibit. One of these shows a
centre composed of quartz -felspar- porphyry passing laterally
through numerous varieties into * claystone '-porphyry. The other
dyke, when traced for some distance, exhibits a change from a fine-
grained porphyritic granite to a rock with a compact semivitreous
ground mass, in which felspar, quartz, and mica are porphyritically
developed.
Mr. Bernard Hobson has lately contributed a paper on the
Basalts and Andesites of Devonshire, known as 4 felspathic traps/
According to this writer it would seem that all but one of the
specimens examined are olivine-basalts. He feels no doubt of the
contemporaneous nature of the lavas exposed in all the localities
visited. This conclusion is in accordance with the views of
De la Beche, and contrary to the statement of Mr. Vicary that "they
commonly appear as dykes filling fissures in the earlier rocks." In
some places the basalt, as he calls it, may be seen to intervene
between the underlying Carboniferous and the overlying Permian (or
Triassic) rocks. Mr. Hobson doubts the connexion of these lavas in
any way with the Dartmoor granite, since the so-called 4 felspathic
traps,' being really olivine-basalts, are not likely to be the effusive
equivalents of the granite. Ho also doubts the intrusion of quartz-
128 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 1S94.
porphyries into the * felspathic traps/ The presence of quartz-
inclusions misled De la Beche into terming these rocks 'quartziferou*
porphyries.'
It would hardly be possible to broach the subject of Devonian
geology without some allusion to the Dartmoor granite. Why the
igneous origin of this particular granite should have been attacked
any more than that of any other is, perhaps, difficult to explain.
It is bigger and more accessible than most of our English granite-
masses, and having become, as it wore, a stock subject, is exhibited
from time to time by the demonstrators in different attitudes to
please the fancy of various audiences. The latest difficulty, it would
seem, arises from the supposed want of a satisfactory explanation
of the structural relations of the granite to the surrounding rocks.
Thus Mr. Ussher has recently announced that " from the relations of
the stratified rocks to the granites of Devon and Cornwall there is
no obtainable evidence as to the upheaval of the latter." 1 Con-
sequently the view is advanced that the granite of Dartmoor
resulted from the metaraorphism of pre-existing rocks which had.
in a rigid state, oxcrcised an obstructive influence on the north-and-
south movements, and had thereby produced great mechanical
effect* on the surrounding strata.
These views of Mr. Ussher were criticized by General M'Mahon.
in a papor entitled ' Notes on Dartmoor/ read before the Society
towards the close of last session. The Author gave some of the
results of a visit to the western borders of Dartmoor, detailing
certain cases of eruptive granite-veins intruding into the Culm-
moasurcs in the immediate vicinity of the main mass of granite.
Tho latter, in the locality described, is porphyritic down to its
boundary, and the veins are also jwrphyritic. All the circumstances
led the Author to believe that theso veins are real apophyses from
the main mass, and that tho viow adopted by De la Beche regarding
the origin of the Dartmoor granite is the true one. He further
commented on the improbability that a tremendous squeeze,
sufficient to fuse such a mass of pre-Dcvonian rock into granite,
should have left the Culm-measures, outside the zone of marginal
contact-metamorphism, almost untouched. It may be that Mr.
Ussher's views on this subject have been somewhat misunderstood,
and an attempt was made to show that this was so. But whatever
they may be, there is such a touch of vagueness about * pro-Devonian '
rock that we may hope for a further revelation on this score.
1 Geol. Mag. 1892, p. 4tf7.
Digitized by Google
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 12<)
Doubtless wo have not heard the last of Dartmoor, but meanwhile
geologists may take comfort in the reflection that the latest writer
on the subject sees good reason to endorse the views of De la Beche.
There is yet one more burning question in connexion with the
county of Devon, viz. the age and character of the Start (or Bolt)
Schists — a problem which, is perhaps, more difficult of solution
than that of tho Dartmoor granite. Supplementary to Prof.
Bonney's well-known paper, written ten years ago, are some notes
on the Metamorphic Rocks of South Devon by Miss Raisin, who
endeavoured to show that the slaty beds to the northward do not
pass into the mica- and chlorite-schi^ts, but are separatod'from the
latter by a line of faults. Some pctrographical details were given,
and an attempt was made to determine the succession of chlorite-
mica- and micaceo-chloritic schists around the Salcombe estuary.
It is nearly seven years since Miss Raisin's paper was read, and
the subject has not again been mooted in the Quarterly Journal,
but papers have been published in tho Transactions of the Devon-
shire Association bearing upon this mattor, and lately Mr. Hunt has
taken up the cudgels against the views of Prof. Bonney and Miss
Raisin. On the whole, there is at present a reaction against the
notion that the metamorphic rocks of South Devon are of Archaean
ago or even older than the adjacent Devonian. Mr. Ussher, indeed, in
his Geological Map of West Somerset, Devon, and Cornwall, issued
in 1892,1 boldly colours the whole as Lower Devonian — a plan
which at least saves the trouble of having to trace a boundary-line.
It would be exceeding my prescribed limits to notice at any
length Mr. Hunt's paper published about a year and a half ago in
the Geological Magazine.3 His object was to endeavour to ascer-
tain what affinities can be detected between the metamorphic rocks
of South Devon and the slates, grits, and volcanic rocks which lie
to the northward of them ; the green rocks being compared with
the volcanics, the mica-schists with the slates, and the quartz-
echists with the fine grits or sandstones. Commencing with the
latter, he observes that the undoubted Devonian sandstones may
be traced into the undoubted metamorphic quartz-schists by four
independent lines of enquiry, viz. by way of iron-ores, tourmalino,
mica, and quartz. In making these comparisons he ['suggests
t hat, with some exceptions, the mica in both the] Devonian and
metamorphic rocks is, or was originally, detrital, the* deposition of
1 Proc. Somerset. Archied. Soc. vol. xxxviiL
3 Vol. for 1892, p. 241. This paper was published in three^ successive
nuroberfl. vi/,. those for June, July, and August.
130 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 1894,
micaceous sediment being much more general in the southern area
than farther north. The comparison between the mica-schists of
the Start region and the Devonian slates is scarcely attempted ;
but much stress is laid upon the analogy between the green rock?
of the me tarn orphic area and what he calls Devonian volcanioj.
As regards the character of the metamorphosis generally, he
discusses certain chemical questions, not forgetting hydrotbermal
action, and proceeds to state that with magnesia and carbonic acid
available from an outside source the process of metamorphism
seems easy. Lastly, he concludes that there is evidence in sopport
of the hypothesis that the metamorphic rocks of South Devon
are Lower Devonian, and of about the same age as the sandstones
and slates with Phurodictyuin probhmaticum of the northern shore
of Torbay.
The notion of the Devonian age of the Start Schists has generally
found favour at Torquay, and recently, as we perceive, authors
have so far grappled with the details that they venture to specify
the Lower Devonians as the beds whose metamorphism has produced
the rocks in question. Now, we have learnt from Mr. Usshers
paper, already quoted under 4 Devonian,' that the Lower Devonians
on the north side of the Dart are devoid- of interbedded igneous
rocks, and that they are essentially a gritty series with some slates
towards the top. But it would seem that the presumed Lower
Devonians on the south-west side of the Dart do contain inter-
bodded sheets of igneous rock, and it is the supposed metamorphism
of these which it is thought may have given rise to the * green
rocks ' of the Start. Admitting, then, for the sake of argument,
that a diabase might, under certain circumstances, become a
" felspathic green rock of gnoissoid character, containing compact
hornblende, much fibrous hornblende, and chlorite," is there any-
thing like a proportionate development of the diabase-rocks of the
presumed Lower Devonian of the Torcross district and the ' green
rocks ' of the metamorphic area ?
This question, of course, can only be answered by geologists who
have made the locality their special study. But apart from Lower
Devonian diabases, which in some districts are not by any means in
evidence, it would seem that the arenaceous Lower Devonians
in general require a considerable amount of bolstering up before
they could bo made to yield rocks like the general type of the
South Devon Metamorphics. Thus, for instance, Mr. Hunt is
obliged to postulate an excess of micaceous sediment for the
Digitized by Google
Vol. 50.J ANNIVER8ABY ADDRESS OF THE PRESIDENT. I 3 I
southern, t. e. for the metamorphic area over and above that of the
beds farther north, t. t. for the unmetamorphosed Devonians. But
perhaps the most unsatisfactory feature in his argument is exhibited
by his calling in the aid of magnesia and carbonic acid from out-
side sources in order to account for these processes of mctamorphism
which seem to him so easy. Meantime, Prof. Bonney expresses
himself yet more confidently than in his original paper as to the dis-
tinction in lithological characters and age between the two groups
of rocks, viz. the metamorphic schists and the slaty Devonian system.
Judging, however, from statements in one of his Channel Island
papers, it would seem that he regards the Start Schists as belonging
to the group of metamorphosed sediments rather thau to that of
schistose igneous rocks. But whatever his views may be, we can
confidently predict that the schists of the Start, liko the granite of
Dartmoor, will still continue to exercise the critical functions of
the Devonshire geologists, unless some indisputable stratigraphical
evidence should happily settle the controversy.
The Lizard. — There have been four papers from well-known
authors dealing with this much-debated peninsula. In the first
paper Mr. Howard Fox described the gneissic rocks which lie off
the Lizard. There are three groups, he observed, apparently
forming a sort of gradation from the outermost coarse gneisses,
through light, banded, granulitic gneisses to the transition micaceous
rocks of the inner reefs, which still more nearly approach the
mainland schists. The inclination of the divisional planes appears
onformablc with that of the rocks of the mainland. Tho gneisses
and granulites are traversed by numerous dykes of porphyritic basic
rock. There are some valuable pctrographic notes to this paper by
Mr. Teall. It was held that the period of dynamic mctamorphism,
of which tho most striking results are seen in the south-western
portion of the Lizard peninsula, was posterior to the formation of
the basic dykes, and that there is no evidence of igneous action in
the district since the period of metamorphisra.
General M°Mahon next contributed some notes on the Horn-
blende Schists and Banded Crystalline Rocks of the Lizard. In
conformity with the views of De la Beche, J. A. Phillips, and
others, he considered that microscopic study proved the schists to
have had a volcanic origin, and to consist principally of ash-beds ;
and he further maintained that there is no evidence that the
foliation of these rocks is due to dynamic deformation. The Author
132 PROCEEDINGS OF Tilt GEOLOGICAL SOCIETY'. [May 1 894.
suggested that the banding of the hornblende-schists was produced
by the action of water, such as circulates about the roots of
volcanoes, leaching out unstable minerals, like pyroxene, from the
spaces between the planes of lamination, and the formation of com-
paratively stable minerals, such as hornblende, along those planes.
The Lizard rocks he regarded as containing good examples of the
formation of hornblende in the wet way, that mineral having been
deposited in cracks so as to join together the ends of hornblende
crystals. The Author considered the * granulitic ' group as in part the
result of converted ash-beds, whilst other portions are composed of
intrusive diorites of later date, the quasi-bedded appearance of both
being due to the injection of granite. In some places the intrusive
character of the granitic veins is undoubted. On the whole, it
would seem that this paper was written at a time when the Author
wished to protest against every case of foliation being quoted as
an instance of dynamic deformation, though ou several points be
was content to suspend his judgment for the present.
The next paper on the Lizard Rocks was a joint contribution from
Prof. Bonney and General McMahon, being the results of a visit in
August 1800. The Authors maintained that tho peridotite, from
which the serpentine is derived, was introduced into the hornblende-
schist and banded granulitic rocks, after these had assumed their
present condition. They assert that there are no signs of any
marked pressure-metamorphism in this rock either prior or posterior
to serpentinization. The streaky or banded structure they have failed
to connect with any foliation or possible pressu restructure in the
schists, and they arc disposed to regard it as resulting from move-
ments while the mass was still in a molten or partially molten
condition. The occasionally banded structure in the gabbro they
also regard as resulting from a kind of fluxional structure. They
now held that the 1 granulitic ' group consists of at least two distinct
rocks— one acid, the other basic, — of which the former was intrusive
in the latter, and that, certain fluxional movements ensuing, the
uniform and stratified aspect of the two varieties was thus produced ;
this movement being followed by crystallization, or completion of
crystallization, in the constituents. The hornblende-schists they
were content to leave a somewhat open question ; and, lastly, they
held that earth-movements have produced marked effects only st the
extreme north and the extreme south of this district, those on the
northmodifying the rocks for a very limited distance.
The latest communication to the Society on the subject of the
Digitized by Google
Vol. 50.] AITOIVERSABY ADDKBS8 OF THE PRESIDENT. t$$
Lizard Rocks was furnished last session by Messrs. Fox and Teall,
who gave a very close description of two limited districts, viz. that
of Ogo Dour and that of the Lion Rock near Kynance. In the
former district they conclude that the hornblende-schist and ser-
pentine form together a banded complex of crystalline foliated
rocks, and that if there is any material difference in age the
serpentine is likely to be the earlier of the two. This, it should be
stated, is an olivine-hornblende serpentine, markedly different from
the common variety. The complex of schist and serpentine has been
folded after the banding was produced, and before the dykes were
intruded, whilst some, if not all, of this folding probably took place
when the complex was formed. The schist and the serpentine are
traversed by dolerito-dykos, which have themselves been converted
into schists, macroscopically indistinguishable from portions of the
normal hornblende-schist of the Lizard peninsula ; faulting has
taken place after the dykes had reached their present condition.
In the Lion Rock district the relations between the serpentine
and the * granulitic ' group are considered. Tho main mass of the
cliff here is formed of serpentine, of which the common variety
weathers red and contains numerous crystals of bastite. Basic
dykes and a gabbro-vein are observed to traverse this, and these
dykes pass occasionally into hornblende-schist. Moreover, they
vary in thickness, and in some of the thicker portions put on
appearances which are characteristic of the 'granulitio' group.
In the section a wedge-shaped mass of typical ' granulitic ' rock is
seen surrounded by serpentine, and tho structure of this mass
appears to be incompatible with the theory that the serpentine was
intruded into it when solid.
As an interesting appendage to this paper the same Authors gave
an account of a Radiolarian Chert from Mullion Island, with the
addition of critical notes by Dr. Hinde. This paper might indeed
have been included in the Pakeontological division, but as a matter
of convenience it is placed along with the rost of the communications
relating to the Lizard. The stratified rocks, which form only a
small portion of the island, consist of chert, shales, and lime-
stone, occurring as thin strips or sheets and sometimes as detached
lenticles within tho prevailing mass of * greenstone,' possibly repre-
senting a subaqueous lava. The chert is of radiolarian origin,
and the radiolaria are often recognizable on the weathered surface
of the beds. Dr. Hinde gave a technical description of the re-
cognizable forms, the genera being included under the suborders
vol. l. k
1 34 MMKJKRDlHes OF THE GEOLOGICAL BOCIBTT. [May 1 894,
Sphieroidea and Prunoidea. Without distinctly stating the age,
he went so far as to remark that, in their general condition of
preservation, the radiolaria in this Cornish chert strongly resemble
those in the Ordovician chert of Scotland. Messrs. Fox and Teal]
regard Mullion Island as belonging to the sedimentary scries which,
on the mainland, is faulted against the Lizard rocks, although they
failed to find the particular beds of the island in any part of the
immediate neighbourhood.
To judge from the foregoing extracts it cannot be doubted that
considerable progress has of late been made towards a recognition
of the true character of the Lizard rocks, which, for the extent of
territory they occupy, are perhaps without equal in point of interest
throughout the British Isles. Prof. Bonney may be said to hare re-
discovered these rocks about seventeen years ago, and his recognition
of the true origin of the serpentine laid the foundation for the correct
diagnosis of the entire peninsula, whilst it put an end to a considerable
amount of crude speculation. Another phase in the history of the
Lizard dates from the publication of Mr. Toall's instructive paper on
the Origin of certain Banded Gneisses,1 wherein he contended that a
series of rocks, hitherto regarded as sedimentary, are really of igneous
origin, and that the parallel structure which characterizes many of
them has nothing to do with stratification in the ordinary sense of
the word, but is a consequence of the deformation to which the
original rock-masses have been subjected.
Practically there is now no dispute, one may .say, as to the cha-
racter of these banded gneisses, which present an appearance so
curiously imitative of sedimentation ; and although there may be a
slight reserve in some quarters as to the possibly pyroclastic origin
of a portion of the hornblende-schist, the rocks of the Iiiard
peninsula, as a whole, are regarded by all as truly igneous.
Amongst the more important issues which yet remain for decision
is the question as to how far the peculiar structure of the banded
gneisses is due to deformation, or to some congenital peculiarity as
suggested by General McMahon. The next question seems likely to
prove a thorny one, viz. the determination of the order of succession
in the several igneous masses. This latter point is really not one of
prime importance, since practically the Lizard rocks, for the most
part, are of one age, and constitute an igneous — possibly a plutonic
— complex, portions of which have been folded, and the whole thrown
into such confusion that the story told by one section may perhaps
1 Geol. Mag. 1887, p. 484.
Digitized by Googfe
Vol. 50.]
ANNIVERSARY ADDRESS OF THE PRESIDENT.
135
be contradicted by tbe next. It is interesting to bear in mind
certain points of resemblance between the Lizard district and the
North-west Highlands indicated by Mr. Teal], more especially as
regards foliated crystalline rocks being cnt by basic dykes, which
themselves pass into schists. So far as it goes, this evidence is in
favour of the generally accepted view that the Lizard rocks are of
Arehscan age. Whether the whole mass segregated from a homo-
geneous magma as held by Mr. Somervail,1 or whether the relations
of the several rook- masses are those of intrusion, is perhaps a
question which cannot be very easily answered. Should the former
view be the correct one, in that case, according to the accepted
determination of the order of crystallization, which we have seen
applied by Messrs. Dakyns and Teall, and quite lately by Prof.
Brogger, the now serpentinized peridotite must have been the earliest
rock to consolidate.
Britanny and the Channel Islands. — A study of the older rocks of
this region may be expected to throw some light on the problems
suggested by the Lizard, and for this reason I venture to cross the
English Channel. The principal authors in this field have been
Prof. Bonney and the Rev. Edwin Hill. It is now nearly eight
years since the excursion of the Geological Society of France
to Britanny drew the attention of geologists to that peninsula.
Dr. Charles Barrois, of Lille, prepared on that occasion an excellent
summary of the geological constitution of Finisttre for the use
of the excursionists, amongst whom was Mr. Hill. Prof. Bonney
acknowledges his obligations to both these gentlemen in the
preparation of his notes on the structure and relations of some
of the older rocks of Britanny. He expressly says that he did
not go there to criticize but to compare, and to ascertain the bearing
of the rocks of Britanny upon general questions of metnmorphism and
the genesis of crystalline schists. He noticed certain glaucophane-
amphibolites and associated schists, which he considered as undoubt-
edly of igneous origin, but subsequently modified by pressure.
The banded gneiss at the embouchure of the Pouldu and at RoscofF,
especially the latter, constantly reminded him of the more typical
members of the ' granulitic ' series at the Lizard, the structures of
which are very difficult to explain on any theory of a ' rolling-out '
of a complicated association of igneous rocks. At that time he
concluded that, while the structures of some foliated rocks may be
» Geol. Mag. 1892, p. 864.
I36 PBOCBEDHTOS OP THE GEOLOGICAL SOCIETY. l&94»
regarded as primarily due to pressure operating upon suitable
materials, the structure of others seemed opposed to this explanation ;
hut, whatever the genesis of these rocks, they are rightly called
Archaean gneisses and schists.
Simultaneously with the last paper appeared one by Mr. Hill
on the Rocks of Sark, Herm, and Jethou. The greater part of the
island of Sark consists of dark hornhlendic banded rocks, which
closely resemble those of the Lizard. Owing to certain appear-
ances, which he describes, the Author at that time concluded that
these rocks originated through some kind of successive deposition,
if not actually from aqueous sedimentation. He thus sums up what
appears to have been the order of geological events : — A mass of
Archaean rock of uncertain origin (the Creux-Harbour gneiss) had
deposited on it a thick series of beds of alternating materials,
principally hornblendic, possibly of volcanic origin. Over these a
mass of granitic or syenitic igneous rock subsequently flowed,
After the solidification of this, but still probably at a very earl}
period, came a great east-and-west nip. Except certain intrusive
dykes there are no later materials with which to continue the history
of Sark. Mr. Hill further insists upon the Archsean age of these
rocks being analogous to rocks elsewhere admittedly pre-Cambrian.
They seem distinctly older, he says, than the unfossiliferous urgilhtes
of Jersey, themselves of extreme antiquity. Some of the views
expressed in this paper have been materially modified quite recently,
but before considering these matters it will be convenient to pro-
ceed with Mr. Hill's next paper on the Channel Islands.
This relates to the rocks of Alderney and the Casquets. Alderney
itself consists for the most part of crystalline igneous rocks, to
which the name of granite may he applied. The general appear-
ance of this is said to recall the diorites and syenites of Guernsey,
but the abundance of mica and the smaller amount of hornblende
connect it rather with the granites of Jethou and Sark. The
minor intrusives are next described, one of the most interesting
being a dark noncrystalline rock of high specific gravity, approaching
somewhat near to a picrite — the first instance known to Mr. Hill in
these islands of an olivine-bearing rock.
The grits constitute an important formation, which may be traced
at intervals from the Casquets on the extreme west to a point cast
of Cherbourg — a distance of 30 miles. The Author remarks that
the current-bedding, arkose materials, and sporadic pebbles, point
to the immediate neighbourhood of a coast similar to the present
Digitized by
Vol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 1 37
one, and at a spot on the southern cliffs of Alderney the grits may
be seen to rest on the crystalline igneous mass. In estimating their
age, it is important to notice that they are seen to be cut by a mica-
trap dyke, related to the korsantons of Britanny, which Dr. Barrois
assigns to the close of the Carboniferous period. On the other
hand, they contain pebbles of the dykes which cut the granites.
From evidence obtained by M. Bigot on the neighbouring mainland,
and corroborated by the Author, it would seem that this series under-
lies the 4 Ores Armoricain,' and may actually be Torridonian in age
as it seems to be in character, though Mr. Hill appears to have
regarded it as belonging to the Upper Cambrian of Lapworth. The
Jersey conglomerates were regarded as probably of the same age
as the Alderney grits, though the external differences are great.
Moreover, the presence of pebbles proceeding from the rhyolites,
which occupy so large an area in the eastern part of Jersey, in the
grits of Alderney and Omonville, is alone sufficient to show that
these rhyolites are not of Permian age, and cannot be placed later
than Cambrian times. Subsequently M. de Lapparent wrote a
short notice in the Quarterly Journal, withdrawing his previously
expressed views as to the Permian age of these porphyritic rocks or
rhyolites.
Tho latest communication respecting tho Channel Islands is the
joint work of Mr. Hill and Prof. Bonney, and again refers to Sark,
which the Authors were led to examine in the hope that its rocks
might afford some clue to the genesis of the hornblende-schists of
the Lizard. Mr. Hill's previous conclusions are summarized, and
amongst other matters it is stated that the planes of foliation of the
gneisses and hornblende-schists generally dip at moderate angles
and outwards from the middle part of the island. This structure
is said to have no connexion with faults, nor does it give any indi-
cation of being a result of crushing, since it has no real resemblance
to the pressure-structure of the Alps or of the North-west High-
lands ; it is, they say, a 4 stratification-foliation,' not a 4 cleavage-
foliation.'
Three kinds of foliated rocks are described and their mutual
relations duly considered. Mr. Hill's Creux-Harbour gneiss, a
reddish biotite-gneiss, moderately foliated, but not banded, is the
lowest in position and apparently the oldest, though there would
seem to be reasons for believing that the rock is really intrusive into
the series which succeeds. This series is represented as consisting
of hornblende-schists, almost identical with those of the Lizard :
l3*
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
[May 1894,
and associated with these are banded gneisses characterized, as a
"whole, by more micaceous bands, some being fairly rich in biotite.
Certain of these gneisses resemble the 4 granulitic ' gToup of the
Lizard, and they are spoken of as being occasionally much 'gnarled'
by subsequent earth-movements after the characteristic structure
had been assumed. But the most remarkable petrologies! feature
of the island is the occurrence of masses of hornblendite, which
are not restricted to any very definite horizon, though they are most
common either just above the basement-gneiss or at no great height
up in the overlying series.
In some places largo masses of this dark-green hornblende-rock
are broken up and traversed by a pale red vein-granite or aplite.
The former rock is drawn out into irregular lenticles, elongated
lumps, and finally streaks, and hss been melted down locally into
the aplite, the result being a well-banded biotite-gneiss, agreeing
with types which are common amongst the Archecan rocks. The
Authors believe, therefore, that Sark presents an example of the
genesis of such a gneiss, and they, moreover, are of opinion that
probably all the above-named rocks are of igneous origin, hut
became solid ultimately under somewhat abnormal conditions, to
which the peculiar structures (which distinguish them from ordinary
igneous rocks) are due. They attribute the banding to fluxienal
movements, anterior to final consolidation, in a mass to some extent
heterogeneous. This hypothesis, they consider, may be applied to
all gneitses or schists which exhibit similar structures — that is, to a
considerable number of the ATchfean rocks.
Apart even from the important change of front exhibited in the
last paper with respect to rocks showing * stratification-foliation/
these communications on the Channel Islands and adjacent main-
land are replete with interest to the British geologist. Seen in the
light of modern research, there could have been no objection to
grouping the several crystalline formations of the Channel Islands
under the heading * Fundamental Rocks/ But when it is remem-
bered that the Jersey conglomerates were once thought to he of
Triassic and the Jersey rhyolites of Permian age, it seemed safer
to consider the whole matter under the heading * Petrology,' rather
than beg the question, as it were, by grouping them with the Fun-
damental Rocks. Nevertheless, there can no longer be any doubt
as to the Archa?an age of most of these crystalline masses, though
perhaps all are not agreed as to the precise interpretation of the word
* Archffian.' We seem, indeed, here to recognize a Lower and an
Digitized by
Vol. 50.] ANNIVERSARY ADDRESS OP THE PRESIDENT. 1 39
Upper Archaean, the latter being represented by the Jersey rhyolites
and Boulay Bay rocks, which may have their analogues in the
Uriconian of the West Midlands, and possibly in the Arvonian or
Pebidian of Wales. But the chief interest centres in the basic
schistose rocks, underlying these, which belong to the Lower, or, as
some would say, to the Archaean proper, and whose origin is now
universally admitted to be igneous. They lie amongst the very
lowest 1 foundation-stones ' of the Earth's crust, whilst the peculiar
structures exhibited by them, and, above all, their markedly basic
character, cannot fail to provoke speculation as to the physical con-
ditions under which they originated. It is not at all likely that
we have heard the last word about the rocks of the Lizard and of
Sark.
Where there is so much to choose from, my difficulty has ever
been to keep the Address within reasonable limits, and this must be
my apology for many omissions. It would, for instance, have been
very interesting to follow Prof. Bonney in his studies of the crys-
talline rocks of the Alps — the more so as these papers of his
embrace a subject provocative of widely different views. The
Society has likewise been indebted to Mr. Rutley for many beauti-
fully illustrated papers, and we have had other excellent peno-
logical work from such well-known authors as Prof. Cole and
Dr. Hatch, not to mention contributions by Captain Hut t on. Prof.
Ulrich, Mr. 0. A. Derby, Dr. Johnston-Lavis, Mr. Emmons, and
other writers who have dealt with foreign petrology.
On the other hand, I must apologize to the Society for the length
of the Address, or rather of the two Addresses, in which I have
endeavoured to remind the Fellows of what they have been doing
and thinking about during the last few yean. You will readily
believe that my object has not been to provide a synopsis of geo-
logical information, but rather to demonstrate the lines on which the
work of the Society has been conducted within the limited period.
.Moreover, the scope of this second Address especially has been retro-
spective rather than critical, although I have not scrupled at times
to add a few remarks, somewhat after the fashion of the Greek
Chorus, to the contentions of the respective authors. The Geological
Society, as we havo seen, is still a pugnacious body, though the
matters over which it fights are, perhaps, less understanded of the
ople than was formerly the case, and for the same reason may
ssibly afcjMBt less general interest, although the work is none the
146 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1894.
less valuable because it requires a certain amount of special training
in order that it may bo appreciated.
And this reflection serves to remind me of the immense amount
of work that has been accomplished in England since the Fathers
of Geology laid the foundations of the science. Without alluding
especially to the valuable Memoirs of the Geological Survey, I may
venture to call your attention to the circumstance that, in December
last, the Geological Magazine saw the end of its third decade,
and has now entered upon its 31st year. The value of this im-
portant auxiliary has long been recognized by geologists, who cannot
be too conscious of the debt they owe to its truly independent
Editor, now, I am happy to say, your President-elect. Nor must we
forget that this year will mark the Jubilee of our own Quarterly
Journal, and that for this solid work of half a century a suitable
Index is in course of preparation. It has at times occurred to me
that, unless some modification is made in the rules which require
entire originality in papers intended for publication, there may be
difficulty at a future date in obtaining a sufficiency of matter to
interest the Fellows in the work which is going forward. How-
ever, the future does not so much concern an outgoing President
as the past ; and glancing at this once more, I may safely assert
that if a student wishes to keep in touch with modern geological
research he should diligently study the recent volumes of our
Quarterly Journal.
Digitized by Google
VoL 50.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. I4I
February 21st, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
Thomas Hargreaves, Esq., Secretary of the Institute of Mines and
Forests of British Guiana, Georgetown, British Guiana ; "William
Maynard Hutchings, Esq., 99 Osborne Road, Ncwcastle-on-Tyne ;
Alfred Edouard Lardeur, Esq., 64 Stamford Street, Blackfriars,
S.E. ; John Nevin, Esq., Littlemoor, Mirfield, Yorkshire ; and the
Rev. James Thomas Pinfold, Mornington, Dunedin, New Zealand,
were elected Fellows of the Society.
The List of Donations to the Library was read.
The President announced that the Sixth Session of the In-
ternational Geological Congress will be held at Zurich from
August 29th to September 2nd, 1894. The meetings are to be
divided iuto three sections : —
1st. General Goology, etc.
2nd. Stratigraphy and Palaeontology.
3rd. Mineralogy and Petrography.
Goologists having papers to present at the Meetings are requested
to notify the same to the Committee, and to send a short abstract
of the subject with which they propose to deal. The Circular is
suspended on the Notice- Board at the Apartments of the Society
for the convenience of those Fellows who may desire further
information.
The following communications were read : —
1 . * On the Relations of the Basic and Acid Rocks of the Tertiary
Volcanic Series of the Inner Hebrides/ By Sir Archibald Geikie,
D.Sc., LL.D., F.R.S., F.G.S.
2. 'Note on the Genus Naiadites, as occurring in the Coal
Formation of Nova Scotia/ By Sir J. William Dawson, C.M.G.,
LL.D., F.R.S., F.G.S. With an Appendix by Dr. Wheelton Hind,
B.S., F.R.C.S., F.G.S.
The following specimens were exhibited
Photographs and rock-specimens from near the head of Glen
Sligachan, Skye, exhibited by Sir Archibald Geikie, D.Sc., LL.D.,
F.R.S., F.G.S., in illustration of his paper.
Specimens exhibited by Sir J. William Dawson, C.M.G., LL.D.,
vol. l. ;
Digitized by Google
1 42 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Aug. 1 894,
F.R.8., F.G.S., and Dr. Wheelton Hind, B.S., F.R.C.S., F.G.S., in
illustration of their paper on the Genus Naiadites.
Specimen of Cave-sandstone (Jurassic) from the Harrismith
District, Orange Free State, exhibited by David Draper, Esq..
F.G.S.
March 7th, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
James W. Bradley, Esq., AssocM.In8t.CE., Oulton Villa, Kelson ;
J. A. Foote, Esq., Ceres, Cupar-Fife; Thomas Edward Knightley,
Esq., Cleve House, Tulse Hill, S.W. ; and Leonard James Spencer,
Esq., B.A., 16 Barclay Road, Walham Green, S.W., were elected
Fellows of the Society.
The List of Donations to the Library was read.
The Secretary announced that a portrait of the late Sir Richani
Owen, K.C.B., F.R.S., F.G.S., had been presented to the Society by
Ernest Swain, Esq., F.G.S.
The following communications wort* read : —
1. ' The Systematic Position of the Trilobites.' By H. M. Bernard,
Esq., M.A., F.L.S., F.Z.S. (Communicated by Dr. Henry Woodward,
F.R.S., P.G.S.)
2. 'Landscape Marble.' By Beeby Thompson, Esq., F.G.S,
F.C.S.
3. * On the Discovery of Molluscs in the Upper Keuper at
Shrew ley, in Warwickshire.' By the Rev. P. B. Brodie, M.A.,
F.G.S.
The following specimens were exhibited : —
Specimens exhibited by Beeby Thompson, Esq., F.G.S., F.C.S., in
illustration of his paj>er.
Arborescent Limestone and Cotham Marble, exhibited by the
Director-General of the Geological Survey.
Arborescent Dendritic Markings on a specimen of Lithographic
Stone from Solenhofen, exhibited by the President.
Molluscan Impressions (Lamellibranch Shells) from the Upper
Keuper Sandstone of Shrewley, Warwick, exhibited by the Rev. P.
B. Brodie, M.A., F.G.S., in illustration of his paper.
Digitized by Google
Vol. 50.J
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
143
March 21st, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
The List of Donations to the Library was read.
The President gave expression to the feelings of regret with
which the Society had received the announcement of the death of
Mi. William Pengelly, F.R.8., of Torquay. He had been a
Follow since 1850, and had taken a leading part in the exploration
of Kent's Cavorn and Brixham Cave.
The following communications were read : —
1. * On the Origin of certain Novaculites and Quartzites.' By
Frank Rutley, Esq., F.G.S., Lecturer on Mineralogy in the Royal
College of Science, London.
2. 1 Note on the Occurrence of Perlitic Cracks in Quartz.' By
W. W. Watts, Esq., M.A., F.G.S.
The following specimens were exhibited : —
Specimens of Ptychoparia Kingi, Meek, from the Cambrian of
South-eastern Nevada, and Triarthnut Becki, Green, from tho Lower
Silurian, near Rome, New York, U.S.A., exhibited by the President.
Specimens and microscope-sections of Novaculites, etc., exhibited
by Frank Rutloy, Esq., F.G.S., in illustration of his paper.
Rock-specimens, microscopic sections, and photographs, exhibited
by W. W. Watts, Esq., M.A., F.G.S., in illustration of his paper.
These and other sections were shown on tho screen by means of a
lantern and lantern-microscope which Messrs. F. Newton & Co. lent
and worked for the occasion.
Microscope-sections of Carboniferous Chert showing Sponge-
spicules and Crystals of Calcite, exhibited by Dr. G. J. Hinde,
V.P.G.S.
April 11th, 1894.
Dr. Hejjry Woodward, F.R.S., President, in the Chair.
Charles William Andrews, Esq., B.A., B.Sc., 68 Edith Road,
West Kensington, W. ; and Charles William Fcnnell, Esq., West-
gate, Wakefield, were elected Fellows ; Prof. E. S. Dana, New
Haven, Conn., U.S.A., a Foreign Member ; Prof. J. P. Iddings,
Chicago, U.S.A., and Prof. J. H. L. Vogt, Christianin, Foreign
Correspondents of the Society.
!
144 PROCEEDINGS OF THE GEOLOGICAL SOCTKTT. [Aug. 1 894.
The List of Donations to the Library was read.
The following communications were read : —
1. 'Mesozoic Rocks and Crystalline Schists in the Lepontinc
Alps.' By T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S., Professor of
Geology in University College, London, and Fellow of St. John's
College, Cambridge.
2. ' Notes on some Trachytes, Metamorphosed Tuffs, and other
Rocks of Igneous Origin, on the Western Flank of Dartmoor.' By
Lieutenant-General C. A. McMahon, F.G.S.
The following specimens were exhibited :■ —
Rock-specimens and microscope-sections, exhibited by Prof. T.G.
Bonney, D.Sc, LL.D., F.R.S., F.G.S., in illustration of his paper.
Rock-specimens and microscope-sections, exhibited by Lieut.-
General C. A. McMahon, F.G.S., in illustration of his paper.
Specimen of Ecca Conglomerate from near Grahamstown, Cape
Colony, exhibited by Dr. J. \V. Gregory, F.G.S.
April 25th, 1S94.
Dr. Henby Woodward, F.R.S., President, in the Chair.
John Charles Burrow, Esq., Trelowarren Street, Camborne,
Cornwall ; and Charles Davison, Esq., M.A., 373 Gillott Road,
Birmingham, were elocted Fellows of the Society.
The List of Donations to the Library was read.
Mr. A. R. Sawyeb, referring to specimens exhibited' by him from
the Transvaal, Orange Free State, Cape Colony, Mashonaland, and
Matabeleland (the last mentioned collected during the recent war),
remarked that gneisses and gneissose granites cover a large portion
of Mashonaland, together with patches of schistose rocks and
a few stratified rocks. Ho drew attention to the fantastic shapes
assumed on weathering by the granitic gneiss, which he considered
solely due to atmospheric agencies, and not to ice-action or to the
effects of submersion.
The schistose rocks are, for the most part, sheared and altered
igneous masses. There are numerous examples of dolerites and
epidiorites passing into hornblende-schists, and of more acid fgm'ons
rocks. Masses of magnetite occur in various parts of Mashonaland,
and serpentinous rocks (which probably owe their origin to the
alteration of peridotites) in the N.W. corner of the Victoria Gold-
field.
* Digitized by Google
Vol. 50.I
PROCEEDINGS OP THE GEOLOGICAL SOCIETY.
Extremely auriferous veins occur amongst the sheared acid
igneous rocks of the Umhungwo Valley in the Manica district, and
gold occurs in the kaolin produced by the disintegration of these
rocks.
The following communications were read : —
1. 4 Further Notes on some Sections on the Now Kail way from
Romford to Upminster, and on the Relations of the Thames Valley
Beds to tho Boulder Clay.' By T. V. Holmes, Esq., F.G.S.
2. 1 On the Geology of the Pleistocene Deposits in the Valley of
the Thames at Twickenham, with Contributions to the Flora and
Fauna of the Period.' By J. R. Leeson, M.D., F.L.S., F.G.S., and
G. B. Laffan, Esq., B.Sc., F.G.8.
3. 4 On a Goniatito from the Lower Coal Measures.' By Herbert
Bolton, Esq., F.R.S.E. (Communicated by George C. Crick, Esq.,
F.G.S.)1
In addition to the specimens mentioned on p. 144, the following
were exhibited : —
Specimens from the new Railway from Romford |to Upminster,
exhibited by T. V. Holmes, Esq., F.G.S., in illustration of his
paper.
Specimens of the Fauna and Flora from the Pleistocene Deposits
at Twickenham, exhibited by Dr. J. R. Leeson, F.L.S., F.G.S., in
illustration of the paper by himself and G. B. Latfan, Esq., B.Sc,
F.G.S.
Specimens of Goniatites, exhibited by Herbert Bolton, Esq.,
F.R. S.E., in illustration of his paper.
Palaeolithic Flint-implement, found in Gravel at the corner of
Jcrmyn Street and Eagle Place, S.W., April 4th, 1894, exhibited
by the Director of tho Museum of Practical Geology.
May 9th, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
Colonel Frederic Taylor Hobson, 83 Queen's Gate, S.W., was
elected a Fellow of the Society.
Tho List of Donations to tho Library was road.
1 This paper has been withdrawn by permission of the Council.
I46 PBOCEEDINGS OF THE GEOLOGICAL SOCIETY. [Aug. 1S94.
Mr. Lydekkek exhibited some specimens from a collection of
Argentine fossil Vertebrates which he bad been allowed to select
from the La Plata Museum for presentation by Dr. Moreno to the
British Museum. Many of these belonged to types previously
quite unrepresented in the collection of the latter. He also drew
attention to his recently published monograph on Argentine Verte-
brates, and stated that he hoped these results of his journey to La
Plata under the auspices of the Royal Society would be regarded as
satisfactory. The difficulty he himself had laboured under, id
endeavouring to understand what had been previously written in
regard to the extinct mammals of Argentina, was largely due to the
absence of satisfactory figures ; and his object had, therefore, been
to figure as many specimens as possible on a large scale, in order
that others might have an opportunity of judging for themselves,
quite apart from his own descriptions and conclusions.
He had undertaken his journey to Argentina somewhat un-
willingly, at the wish of Sir W. H. Flower and Mr. Sdater ; but he
had been so interested in what he had seen, that he hoped means
might be afforded him of repeating his visit this year.
The following communications were read : —
1. 'Carrock Fell: a Study in the Variation of Igneous Bock-
masses.— Part I. The Gabbro/ By Alfred Harker, Esq., MA.,
F.G.S.
2. ' The Geology of Monte Chaberton.' By A. M. Davies, Esq.,
B.Sc., F.G.S., and J. W. Gregory, D.Sc, F.G.S.
3. 4 Cone-in-Cone. How it occurs in the Devonian (?) Series
in Pennsylvania, U.S.A., with further details of its Structure,
Varieties, etc' By W. 8. Gresley, Esq., F.G.S.
In addition to the specimens described by Mr. Lydekker (see
above) the following were exhibited: —
Rock-specimens and microscope-sections, exhibited by Alfred
Harker, Esq., M.A., F.G.S., in illustration of his paper.
Specimens and microscope-sections, exhibited by A. M. Davies,
Esq., B.Sc, F.G.S., and Dr. J. W. Gregory, F.G.S., in illustration
of their paper.
Flint-implements, etc, from Bournemouth, Christchurch, Wells
(Norfolk), and Shoreham (Kent), exhibited by the Rev. R. Ashing-
ton Bullen, B.A., F.G.S.
Specimen of Lazulite from Madagascar, exhibited on behalf of th«
Rev. Richard Baron by W. W. Watts, Esq., M.A., F.G.S.
i
■
i
i
9
i
Digitized by Googl
Vol. 50.] PROCEEDINGS OF THE GEOLOGICAL 80CIETT.
147
May 23rd, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
Adolphus Eugene Walton, Esq., Henley Cottage, Hendon, N.W. ;
and Arthur Prangley Wilson, Esq., Assoc.M.Inst.CE., Rodwold,
Chialehuret, were elected Fellows of the Society.
The List of Donations to the Library was read.
The following communications were read : —
1. 'On the Stratigraphy and the Physiography of the Libyan
Desert of Egypt.' By Captain H. 0. Lyons, K.E., F.G.8.
2. ' Notes on the Geology of South-eastern Africa.' By David
Draper, Esq., F.G.S.
3. * The Occurrence of Dolomite in South Africa.' By David
Draper, Esq., F.G.S.
4. 4 Contributions to the Geology of British East Africa. — Part I.
The Glacial Geology of Mount Kenya.' By J. W. Gregory, D.Sc.,
F.G.S.
The following specimens were exhibited : —
Specimens of Rocks, Fossil Wood, Flint-implements, etc., and
also Microscope-sections, exhibited by Capt. H. G. Lyons, R.E.,
F.G.S., in illustration of his paper.
Specimens of Conglomerate, from the Table Mountain Series,
Znluland, and a specimen of Anthracito from the Molteno Beds.
St. Lucia Bay, exhibited by D. Draper, Esq., F.G.S., in illustration
of his papers.
Rock-specimens and Gold Nuggets from Pilgrim's Rest, etc.,
Lydenburg District, Transvaal, exhibited by Nicol Brown, Esq.,
F.G.S.
Microscope-section of a specimen from the Cave Sandstone of the
Harrismith District, Orange Free State, exhibited by the President.
A Quartzite-boulder found in the Chalk of West Thurrock, ex-
hibited by J. J. H. Teall, Esq., M.A., F.R.S., Seo.G.S., on behalf of
W. Martin Leake, Esq.
June 6th, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
Finlay Loriraer Kitchin, Esq., B.A., St. John's College, Cambridge,
was elected a Fellow ; and Monsieur P. de Loriol-Lcfort, of Goneva,
a Foreign Correspondent of the Society.
r48
PROCEEDINGS OP TIIE GEOLOGICAL SOCIETY. [^US' ^9+.
The names of certain Fellows were read out for the first time, in
conformity with the Bye-laws, Section VI. Article 5, in consequence
of the non-payment of arrears of contributions.
The List of Donations to the Library waa read.
The following communications were read : —
1 . ' On the Banded Structure of some Tertiary Gabbros in the
Isle of Skye.' By Sir Archibald Geikie, LL.D., D.Sc., F.R.S., F.G.S.,
and J. J. H. Teall, Esq., M.A., F.R.8., Sec.G.S.
2. 'On the Microscopical Structure of the Derbyshire Car-
boniferous Dolerites and Tuffs.' By H. H. Arnold-Bemrose, Esq.,
M.A., F.G.S.
3. 4 A Comparison of the Permian Breccias of the Midlands with
the Upper Carboniferous Glacial Deposits of India and Australia."
By R. D. Oldham, Esq., F.G.S.
The following specimens were exhibited : —
Rock-specimens, microscope-sections, and lantern-photographs,
exhibited bv Sir Archibald Geikie, LL.D., D.Sc., F.R.S., F.G.S., and
J. J. H. Teall, Esq., M.A., F.R.S., Sec.G.S., in illustration of their
paper.
Specimens, microscope-sections, and lantern -photographs of sec-
tions of Derbyshire Carboniferous Dolerites and Tuffs, exhibited by
H. H. Arnold-Bemrose, Esq., M.A., F.G.S., in illustration of his
paper.
Specimens exhibited by the Geological Survey of England and
Wales, to illustrate the paper by R. D. Oldham, Esq., F.G.S.
Scratched fragments of Permian Breccia from Abberley, and a
Facetted Pebble from the Carboniferous Boulder-bed of the Salt
Range, India, exhibited by R. D. Oldham, Esq., F.G.S., in illustra-
tion of his paper.
Kantengcrollo from Copitz near Dresden, exhibited by R. D.
Oldham, Esq., F.G.S.
June 20th, 1894.
Dr. Henry Woodward, F.R.S., President, in the Chair.
James Knight, Esq., M.A., B.Sc, 121 Kenmure Street, Pollok-
shield9, Glasgow, was elected a Fellow ; and Professor Alphonse
Renard, of Ghent, a Foreign Member of the Society.
The following names of Fellows of the Society were read out for
the second time, in conformity with the Bye-laws, Section VI.
Article 5, in consequence of the non-payment of arrears of con-
Digitized by Google
Vol. 50. j PROCEEDINGS OK THE GEOLOGICAL SOCIETY. 1 49
tributions: — W. J. R. Cowell, Esq.; T. A. Dash, Esq.; F. J.
A. Matthews, Esq.; C. Parker, Esq.; E. M. Richards, Esq.;
Rev. J. C. Roberts ; S. Rogers, Esq. ; J. Ruscoe, Esq. ; U. P.
Swinburne, Esq. ; Dr. J. E. Taylor ; T. C. Townsend, Esq. ; C. H.
T rinks, Est]. ; and S. J. Truscott, Esq.
The List of Donations to the Library was read.
The following communications were read: —
1. 'On Deep Borings at Culford and Winkfield, with Notes on
those at Ware and Cheshunt., By W. Whitaker, Esq., B.A., F.R.S.,
F.G.S., and A. J. Jukes-Browne, Esq., B.A., F.O.S.
2. * The Bargate Beds of Surrey, and their Microscopic Contents.'
By Frederick Chapman, Esq., F.R.M.S. (Communicated by Prof.
T. Rupert Jones, F.R.S., F.O.S.)
3. 4 On Deposits from Snowdrift, with Especial Reference to the
Origin of the Loess and the Preservation of Mammoth-remains/
By Charles Davison, Esq., M.A., F.G.S.
4. * Additions to the Fauna of the Olenell W-zone of the North-
west Highlands.' By B. N. Peach, Esq., F.R.S., F.G.S. (Com-
municated by permission of the Director- General of the Geological
Survey.)
5. k Questions relating to the Formation of Coal-Seams, including
a New Theory of them : suggested by Field and other Observations
made during the past decade on both sides of the Atlantic.' By
W. S. Gresley, Esq., F.G.S.
6. 4 Observations regarding the Occurrence of Anthracite generally,
with a new Theory as to its Origin/ By W. S. Gresley, Esq.,
F.G.S.
7. ' The Igneous Rocks of the Neighbourhood of Builth.' By
Henry Woods, Esq., M.A., F.G.S.
8. 4 On the Relations of some of the Older Fragmental Rocks in
North-west Caernarvonshire.' By Prof. T. G. Bonney, D.Sc, LL.D.,
F.R.S., F.G.S., and Miss Catherine A. Raisin, B.Sc.
The following specimens were exhibited
Specimens from the Deep Borings at Culford, Ware, and Turn-
ford, exhibited by W. Whitaker, Esq., B.A., F.R.S., F.G.S., and
A. J. Jukes-Browne, Esq., B.A., F.G.S., in illustration of their paper.
Rock-specimens and microscope-sections from the Bargate Beds
of Surrey, exhibited by F. Chapman, Esq., in illustration of his
paper.
vol. l. m
I5O PROCEEDINGS OF THE GEOLOGICAL SOCIETY* [Aug. 1 894.
Specimen of Deposit from the surface of a Snowdrift, exhibited
by Charles Davison, Esq., M.A., F.G.S., in illustration of his paper.
Specimens exhibited by the Geological Survey in illustration of
the paper on the Olendhis-zone Fauna by B. N. Peach, Esq.,
F.R.S., F.G.S.
Microscope-sections and rock-specimens from the neighbourhood
of Builth, exhibited by Henry Woods, Esq., M.A., F.G.S., in illus-
tration of his paper.
Rock-specimens and microscope-sections, exhibited in illustration
of their paper by Prof. T. G. Bonney, D.Sc, LL.D., F.R.S., F.G.S.,
and Miss Catherine A. Raisin, B.Sc.
A Special General Meeting was held at 7.45 p.m., before the
Ordinary General Meeting, for the purpose of altering and re-enact-
ing Article 6\ Section VI. of the Bye-laws, which, as now altered,
reads as follows : —
A Fellow may at any time compound for future Annual Contri-
butions, that of the current year inclusive, by payment of Thirty-
five pounds, or if elected before the 1st November, 1894, by «
payment of Thirty-one pounds Ten shillings, or if elected before tie
1st November, 1877, by a payment of Twenty-one pounds. If be
has already paid the Contribution for the current year, or any part
of it, such payment shall be reckoned as forming a portion of tk
Composition.
N.B.— As to the Composition-fee for Non-llesident Fellows elected
between November 2nd, 1859, and March 1st, 1862, see Appendix 4
to Bye-Laws.
Digitized by Google
ADDITIONS
TO THE
LIBRARY AND MUSEUM OF THE GEOLOGICAL SOCIETY.
Session 1893-94.
ADDITIONS TO THE LIBRARY.
1. Periodicals and Publications op Learned Societies.
Presented by the respective Societies and Editors, if not otherwise
stated.
Adelaide. Royal Society of South Australia. Transactions. Vol. xvi.
Part 2. 1893.
V. Streich. Scientific Results of the Elder Exploring Expedition :
Geology, 74. — R. Tate. List of Rock-specimens from east of Mure hi sod
Goldheld, 113.
. . . Vol. xvii. Parts 1 & 2. 1893.
G. A. Goyder. On a new Mineral (Stihiotantalite), 127. — R. Tate and
J. Dennant. Correlation of Marine Tertiaries of Australia, 203. — R. Tate.
The Gastropods of the Older Tertiary of Australia, 316. — W. Howchin.
Tarkaninna and Mirrabuckinna Borings, with special reference to the
Foraminifera observed therein, 346.
Albany. University of the State of New York. New York State
Museum. Forty-fifth Annual Report of the Regents for the
year 1891. 1892.
. . . Forty-sixth Annual Report of the Regents
for the year 1892. 1893.
. . . Bulletin. Vol. iii. No. 11. 1893.
F. J. H. Merrill. Salt and Gypsum Industries of New York, 1.
Alnwick. Berwickshire Naturalists' Club. History of the Ber-
wickshire Naturalists' Club, instituted September 22, 1831.
Vol. xiv. Part 1. 1892.
VOL. L.
n
ADDITIONS TO THE LIBRARY.
[Not. 1894,
Amsterdam. Jaarboek van het Mijnwezen in Nederlandsch Oost-
Indie. Jaargang 22*. 1893. Technisch en Administratief en
Wetenschappelijk Gedeelte. 1893. And Atlas. Presented}^
His Excellency the Netherlands Minister for the Colonies.
A. Hooze. Topografische, Geologische, Mineralogiache en Mijnbouw-
kundige Beachrijving van een gedeelte der afdeeling Martapoera in de
reaidentie Zuider- en Oosterafdooling van Borneo, 1.
Baltimore. U. S. Department of Agriculture. Weather Bureau.
See Books. United States.
Barnsley (Newcastle-upon-Tyne). Midland Institute of Mining,
Civil, and Mechanical Engineers. Proceedings. Vol. xiii.
Parts 120-122. 1893.
BaseL Schweizerische naturforschende Gesellschaft. Verhand-
lungen, 1892. 1892.
Bericht der geologiachen Kommiaaion fur das Jahr 1891-92, 99.
. Schweizerische palaontologische Gesellschaft. Abhand-
lungen. Vol. xx. 1893. 1894. Purchased.
E. Greppin. fitude sur lea mollusques des couches coralligenes d'Ober-
buchaitten. — II. Haas. Kritische Beitrage zur Kenntnisa der juraasischen
Brachiopodenfauna dea Juragebirges, III. Theil.— Ii. Haeualer. Die
Lagenidenfauna der Pholadomyenmergel von St. Sulpice. — P. de Loriol.
Description dea molluaquea des couches sequaniennea de Tonnerre, avec
une e"tude stratigraphique par J. Lambert
Bath. Bath Natural History and Antiquarian Field Club. Pro-
ceedings. Vol. viii. No. 1, 1894. 1894.
Report of Excursion to Brockley Combe and Congreabury, 68.
Belfast. Natural History and Philosophical Society. Report and
Proceedings for the Session 1892-93. 1894.
Berlin. Deutsche geologische Gesellschaft. Zeitschrift Band
xliv. Heft 4 (1892). 1893.
C. Schluter. Protospongia rhenana, 615. — O. Jaekel. Ueber Plicflto-
criniden, Hyocrinus und Sacoocomaf 619. — P. Oppenheim. Ueber einige
Brackwaaser- und Binnenmolluaken aua der Kreide und dem Eocan
Ungarna, 697. — R. Kramata. Strudelloch im Lomnitzthal, 819.— Lem*
berg. Zum mikrochemischen Nachweis dea Eisens, 823. — A. Andreae.
Ueber Hornblendekeraantit und den Quarzmelapbyr von Albersweilar
R.-Pf., 824. — J. Bohm. Ueber das Rhat(P) am Antelao, 836.— Schu-
macher. Ueber die Gliederung der pliocanen und pleiatocanen Ablage-
rungen im Elaaaa, 828.
. . . Bandxlv. Hofte 1-3. 1893.
E. Fraas. Die Irpfelhohle im* Brenzthale ( Wiirttemberg), L— E. W.
flilgard. Die Bodenverhaltnisae Californiens, 15. — W. Daniea. Ueber
das vorkommen von Ichthyopterygiern im Tithon Argentinians, 23."
A. Hoaius. Ueber marine Scnichten im Walderthon von Gronau (West'
falen) und die mit denselben vorkommenden Bildungen {liAizocoralliv™
Mohendahli, aog. Dreibeine), 84. — C. Sapper. Bemerkun^en iiber die
raumliche Vertneilung una morphologiscnen Eigenthumhchkeiten der
Vulcane Guatemalan, 54. — W. Muller. Kunstliche Bildung von Ei*?n-
glanz und Magnetit in den Eisenruckatanden der Anilinfabriken, 68.—
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 1 53
E. Kalkowsky. Ueber Geroll-Thonschieferglacialen Ursprungs im Kulm
des Frankenwaldes, 69. — K. A. Philippi. Vorlautige Nachricht iiber
fossile Saugethierkuochen von Ulloma, Bolivia, 87. — H. Potonie\ Eine
gewohnliche Art der Erhaltung von Stigmaria als Beweis fiir die Autoch-
thonie von Carbon-Pflanzen, 07. — J. von Sieiuiradzki. Der obere Jura
in Polen und seine Fauna, 103. — P. Oppenheim. Die Melanien der
brasilianiscken Kreide, 145. — P. Oppenheim. Neue (pliocane) Melano-
steiren aus Epirus, 145. — F. Schrodt Weitere Beitrage zur Neogenfauna
Sud spaniens, 162. — G. Dewalque. Dreis&cnsia, nicht Dreyssensia, 157. —
G. Bohm. Ueber fossile Ophiuren, 158. — 0. Lang. Die vulcanischen
Herde am Golfe von Neapel, 177. — R. Michael. Cenoman und Turon in
der Gegend von Cudowa in Schlesien, 195. — W. Deecke. Der ober
Dogger vom Karziirer Ufer auf der Insel Wollin, 245. — F. Klockinann.
Uebersicht iiber die Geologie des nordwestlichen Oberharzes, 253. —
F. \\ ahnschaffe. Ergebnisse einer Tiefbobrung in Niederschonweide bei
Berlin, 288. — M. Koch. Mittheilung iiber einen Fundpunkt von Unter-
carbon-Fauna in der Grauwackenzone der Nordalpen, 294. — A. \V. Stelz-
ner. Ueber eigenthiimliche Obsidian-Bomben aus Australien, 299. —
E. Koken. Beitrage zur Kenntniss der Gattung Nathosaurus, 337. —
M. Fiebelkorn. Die norddeutschen Geschiebe der oberen Juraforniation,
378. — C. A. Tenne. Ueber Gesteine der uthiopischen Vulkanreihe, 461.
— 0. Futterer. Ueber Hippuriten von Nahresina, 477. — A. von Strom-
beck. Ueber den angebhchen (tault bei Liineberg, 489. — A. Hal far.
Geologische Ferienreise im Nordwestharz, 498. — R. Michael. Encrinxu
sp. von Chorulla,Ober-Schlesien, 500. — E. Keilhack. Fossile Characeen
von Klinge, 503.
Berlin. Gesellschaft naturforschender Freundc. Sitzungsberichte.
Jahrgang 1892. 1892.
A. Nehring. Notizen iiber Cervits megaceros, var. Rujfi, Nhrg., und iiber
das diiuviale Torflager von Klinge bei Cottbus, 3, 27. — Schaff. Ueber
Insektenreste aus dem Torflager von Klinge, 8. — O. Jaekel. Ueber
Ctedodu* und seine Bedeutung fur die Phylogenie der Extremitaten, 80.
— H. Potonie\ Ueber die den Wasserspalten physiologisch entsprech-
enden Organe bei fossilen und recenten Farnarten, 117. — A. Nehring.
Ueber Atlas und Epistropheus des Bos primigenius, 129.— 0. Jaekel.
Ueber Chalcodus permianus, 156. — A. Nehring. Bemerkungen zu Cred-
ner's Arbeit iiber die geologische Stellung der Klinger Schichten, 158. —
F. Wahn.schaffe. Ueber die Entstehung und Altersstellung des Klinger
Torrlagers, 195. — H. Potonie\ Ueber die f Rathselfrucht ' {Paradoxo-
carptts carinatusy A. Nehring) aus dem diluvialen Torflager von Klinge
bei Kottbus, 199. — A. Nehring. Ueber die Vertheilung der Pflanzenreste
innerhalb bes diluvialen Torflagers von Klinge, 212.
— . Koniglich preussisch© Akademie der WissenBchaften.
Sitzungsberichte, 1893. Nos. 1-58. 1893.
F. Rinne. Ueber norddeutsche Basal te, 41. — G. Linck. Ueber Her-
cynit aus dem Veltlin, 47. — K. Futterer. Die Gliederung der oberen
Kreide in Friaul, 847. — H. Biicking. Sulfoborit, ein neues krystallisirtes
Borat von Westeregeln, 967. — W. Dames. Ueber die Gliederung der
Fliitzformationen Helgolands, 1019.
. Koniglich proussische geologische Landesanstalt und Berg-
akademie. Jahrbuch fiir das Jahr 1889. Band x. 1892.
Mittheilungen aus der Anstalt, ix.
Abhandlungen rxm Mitarbeitem,
H. Proescholdt. Ueber Thalbildung im oberen Werragebiet, 1.—
n2
■
i54
ADDITIONS TO THE LIBRARY.
[Not. 1894.
H. Potonie\ Ueber einige Carbon fame, 21.— H. Bucking. Das Gmud-
gebirge des Spessarts, 28. — H. Grebe. Ueber Tertiar-VorkommeD 10
beiden Seiten des Rheines zwischen Bingen und Lahnstein und Weiteiw
iiber Thalbildung am Rhein, an der Saar und Mosel, 99. — K. A. Lo&en
und F. Wahnschaffe. Beitrage zur Beurtheilung der Frage nach einer
eiiiatigen Vergletscherung des Brocken-Gebietes, 124. — G. Miiller. Die
Rudisten der oberen Kreide am nordlichen Harzrande, 1S7. — K. Keilhack.
Der baltische Hohenriicken in Hinterpommern und Westpreussen, 149.—
r. Ebert, Preshcichia (Euproops) Scheeleana, n. sp., 215. — H. Loretz.
Der Zechstein in der Gegend Ton Blankenburg und Konigsee am Thu-
ringer Walde, 221. — H. Potonie\ Der im Lichthof der Konigl. geolo-
c-iachen Landesanstalt und Bergakademie aufgestellte Baumstumpf mil
Wurzeln aus dem Carbon des Piesberges, 246. — K. A. Lessen. Ver-
Sleicbende Studien iiber die Gesteine des Spiemonts und des Bosenberp
ei St. Wendel und verwandte benachbarte Eruptivtypen aus Zeit des
Rothliegendcn, 258. — £. Zimniermann. Ein neuer Nautilus aus dem
Grenzdolomit des thiiringischen Keupers ( Trematodiscus jugatonodom),
822.— F. Wahnscbaffe. Be it rag zur Loasfrage, 328. — G. Berendt. Die
Soolbohrungen im Weichbilde der Stadt Berlm, 347.
Abhandlungm von atuserhalb.
W. Ule. Die Tiefenverhaltnisse der Masuriscben Seen, 3. — C. Struck-
mann. Die Grenzscbicbten zwischen Hilsthon und Wealden bei Bar-
singbausen am Deister, 65. — J. Kiesow. Beitrag zur Kenntnisa der in
weatpreussiscben Silurgescbieben gefundenen Ostracoden, 80. — W.
Langsdorff. Beitrage zur geologischen Kenntnisa des nordwestlicbeo
Oberharzes, insbesondere in der Umgebung Ton I>autentbal und im Inner-
ate thai, 104. — W. Branco. Ueber das Gebiss von Lepidotu* Koewni,
Br., und Hauchccornei, Br., 124. — A. Martin. Untersuchungeo eines
OliTingabbroa aus der Gegend von Harzberg, 129.
Berlin. Kbuiglich preussische geologische Landesanstalt und Berg-
akademie. Jahrbuch fur das Jahr 1890. Band xi. 1892.
Mittheilungen aus der Anatalt, vii.
Abhandlungm. von Mitarbeitern.
L. Beuahausen. Amnigenia rhenana, n. sp., ein Anodonta ahnlicher
Zweischaler aus dem rheiniachen Mitteldevon, 1. — II. Potonie\ Leber
einige Carbonfarne, 11. — A. Leppla. Ueber die Zechsteinformation und
den unteren Buntsandstein im Waldeckischen, 40.— G. Berendt. Erboh-
rung rurassischer Schichten unter dem Tertiar in Hermsdorf bei Berlin,
83. — E. K ayser. Ueber einige Versteinerungen der Siegener Grauwacke,
95. — E. Kayser. Zur Frage der Vergletscherung des Brockengebietef,
108.— F. rUockniann. Ueber den geologischen Bau des sogenannten
Magdeburger Uferrandes, 118. — A. von koenen. Ueber Paleocan an*
einem Bohrloch bei Licbterfelde, 267.— F. Wahnschaffe. Ueber einen
Grandriicken bei Lubaaz, 277.
Abhandlungm von auuerhalb.
R. Wedel. Ueber den Dolerit der Breitfirst und ihrer Nachbar^rmft.
I. — Von Rosenberg-Lipinsky. Die Verbreitung der Braunkoblenfanna-
tion in der Provinz Poaen, 38. — F. Kuchenbucn. Das Lias-VorkoDlnl«',
bei Volkmarsen, 74.— W. UJe. Die Tiefenverhaltnisse der Osthobwin-
ischen Seen, 102.
. . Jahrbuch fur das Jahr 1891. Band xii. 1893.
Mittheilungen aus der Anatalt, vii.
Abhandlungen von Mitarbeitern.
H. Potonie", Ueber einige Carbonfarne, III. Theil, 1.— G. Berendt
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
Spuren einer Ver^letscherunff des Riesengebirgea, 37. — R. Scheibe.
Ueber Ilauchecornit, ein Nickelwismuthsulhd von der Grube Friedrich
(Revier Hamm a. d. Sieg), 91. — J. H. Kloos. Die geognostiachen Ver-
haltnisse am nordwestlichen Harzrande zwischen Seesen und Habausen
unter specieller Beriickaichtigung der Zechateinformation, 126. — L. Beus-
hausen. Ueber Hypos tome von Homalonoten, 164. — F. Wahnschafle.
Bericht iiber den von der geologischen Gesellschaft in Lille veranstal-
teten Ausflug in das Quartargebiot des nordlichen Frankreich und siid-
lichen Belgien, 167. — W. Frantzen. Bemerkungen iiber die Schicbten
des Oberen Muschelkalks und Unteren Keupers in dem Bereiche der
Messtichblatter Eisenach, Creuzburg und Berka, 179. — E. Dathe. Die
Strahlsteinschiefer des Eulengebirges, 193. — A. Denckmann. Die Frank-
enberger Permbildungen, 234. — T. Wolfer. Bericht iiber einen Grand-
riicken bei dem Dorfe Krschywagura siidlich Wreschen, 268.
Abhandlungen von ausserhalb.
W. Hocks. Der Froschberg im Siebengebirge, 1. — R. Althaus.
Riegelbildungen im Waldenburger Steinkohlengebirge, 18. — R. Althaus.
Die Erzformation des Muschelkalks in Oberschlesien, 37. — A. Dannen-
berg. Der Leilenkopf, ein Aschenvulkan des Laacher-See-Gebietes, 99.
— C. Diitting. Beitrage zur Kenntniss der Geologic der Gegend von
Borgloh una Wellingholzhausen, 124. — H. Eck. Zur Literatur von
Riidersdorf und Umgegend, 156. — Von Rosenberg-Lipinsky. Die Ver-
breituug der Braunkohlenforraation im nordlichen Theil der Proving
Schlesien, 162. — K. Schumann. Untersuchungen iiber die Rhizocaloen,
226. — J. P. Smith. Die Jurabildungen des Kahlberges bei Echte, 288.
Berlin. Koniglich preussischo goologischo Landesanstalt und Berg-
akademie. Jahrbuch fiir das Jahr 1892. Band xiii. 1893.
Mittheilungen aus der Anstalt, vii.
Abhandlungen von Mitarbeitern.
H. Potonie\ Ueber einige Carbonfarne, 1. — A. Denckmann. Schwarze
Goniatiten-Kalke ira Mitteldevon des Kellerwaldgebirges, 12. — G. Muller.
Ueber das Vorkommen von Ancylocera* ^<w-Schichten bei Mellendorf
nordlvch Hannover, 16. — A. Leppla. Ueber den Bau der pfalzischen
Nordvogesen und des triadischen Weatriches, 23. — L. Beushausen. Ueber
den Bau des Schlosses bei Mecunodus, nebst Bemerkungen iiber die
Synonymik einiger Zweischaler des rheinischen Devon, 91. — A. Denck-
mann. Studien im Deutschen Lias, 98. — II. Loretz. Bemerkungen iiber
die Lagerung des Rothliegenden aiidlich von llmenau in Thiiringen, 115.
— H. Loretz. Bemerkungen iiber den 11 Paramelaphyr," 129. — W.
Frantzen. Untersuchungen iiber die Diagonalstructur verschiedner
Schichten mit Riicksicht auf die Entstehung derselben im Buntsandstein
und iiber die Bewegungen zwiachen Landfeste und Meer zur Zeit der
Ablagerung des Buntsandstein^ und des Muschelkalks in Deutschland,
138— K. Keilhack. Der Koschenberg bei Senftenberg, 177.— A. Halfar.
Die erste Asteride aus den palaozoischen Schichten des Harzes, 186.
Abhandlungen von ausserhalb.
F. Rinne. Ueber norddeutsche Basalte aus dem Gebiete der Weser
und den angrenzenden Gebieten der Werra und Fulda, 3. — L. Souheur.
Die Lagerstatte der Zink-, Blei-, und Kupfererzgrube "Gute Hoffnung"
bei Werlau am Rhein, 96.
I56 ADDITI0K8 TO THE LIBRAE*. [NOV. 1 894,
Berlin. Zoitschrift fiir das Berg-, Hiitten- und Salinenwesen im
preussischen Staate. Band xli Hefte 2-4. 1893.
Abhandlungen.
Juan Pie* y AUue\ Ueber die Eisenerz- und Bleiera-Lagerstatten im
bstlichen Spanien, 73.
. . . Atlas, Hefte 2-4. 1893.
. . . Statistische Lieferung. Hefte 1-3.
1893.
. . Band xlii. Hefte 1 & 2. 1894.
A bhnyi dlu ngen .
Jasper. Der Silbererz-Bergbau in Markirch (Elsass), 68. — E. Ilarber.
Per Blei- und Zinkerzbergbau bei Ramsbeck im Berjrrevier Brilon,
unter besonderer Beriicksicbtigung der geoguoatiachen und minenlo-
gischen Verhaltnisse der Erzlagerstatten, 77.
. . . Atlas, Hefte 1 & 2. 1894.
. Zeit8chrift fiir praktische Geologic. 1893. Hefte 1-12.
1893. Purchased.
F. Beyschlag. Geologische Specielaumahmen, 2, 89. — J. H. L. Vogt
Bildung von Erzlagerstatten durch Difierentiationsprocesse in basiscben
Eruptivmagma, 4, 125, 257. — F. Wahnschafie. Geologie und Ackerbau,
11. — T. Breidenbach. Das Goldvorkommen im nbrdlichen Spanien, 16,
49.— P. Groth. Ueber neuere Untersuchungen ostalpiner Erzl^r-
statten, 20. — R. Beck. Das Steinkohlenbecken des Plauen'schen Grunde*
bei Dresden, 24. — H. Helmhacker. Die Mineralkohlen in Russisch-AsieD,
32, 54, 148. — C. Ochsenius. Ueber unterirdische WasseraufcammJuflgeD,
36.— C. Ochsenius. Die Bildung des Kalisalpeter* aus Mutterlaugen-
palzen, 60. — A. Brunlechner. Das Grundwasser im Becken von Klagvn-
furt. 68. — E. Diekmann. Zur Entstehung des sog. Fichteieees, 75.—
A. Goldberg. Ueber Entstehung der Mineralquellen, insbesondere iiber
die dabei stattfindenden chemischen Processe, 92. — A. Leppla. Uebei
das Vorkommen natiirlicher Quellen in den pfalzischen kord-Vop**n
(Hartgebirge), 100. — A. Denkmann. Ueber das Vorkommen von Mergel
in den mesozoischen Schichten einigor Gegenden Nordwest- und Mittel-
Deutschlands, 112. — E. Geinitz. Die Grossherzoglich Meddenburgifcbe
geologische Landesanstalt zu Rostock, 173.— L. Litschauer. Die Ver-
theilung der Erze in den Lagerstatten der metallischen Mineralien, 174.—
F. M. Stanflf. Taraspit, 182. — A. Hofmann. Einiges iiber die Aufetel-
lung von Lagerstattensammlungen, 186. — C. Ochsenius. Bedeutung des
orographischen Elementes "Barre" in Hinsicht auf Bildungen und
Veranderungen von Lagerstatten und Gesteinen, 189, 217. — W. Aloricke.
Betrachtungen und Beobnchtungen iiber die Entstehung von Goldlager-
statten, 143. — J. H. Kloos. Die Tropfsteinhohlen bei Rubeland im Ha«
und ihre Entstehung durch unterirdische Wasserwirkung, 167.— C. T«r-
nuzzer. Die Manganerze bei Roflha im Oberhalbstein, Graubiinden,
— H. Credner. Die geoloeische Landesuntersuchung des Konigreichea
Sachsen, 253. — A. Brunlechner. Die Form der Eisenerzlagerstatten in
Hiittenberg (Karnten), 801.— J. Haberfelner. Das Erzvorkommen ron
Cinque-valle bei Roncegno in Siidtirol, 307. — M. Lodin. Die Engin?8
von Pontgibaud, 310. — A. Sauer. Die neue geologische Landesaufiisbm*
des Grosah. Baden, 333. — F. Beyschlag. Geologische Kartenaufbabnw0
Digitized by Googl
Vol. 50.]
ADDITIONS TO THE LIBRARY,
157
Ton Oesterreich-Ungarn und einiger Nachbarlander, 336. — W. Ule.
Ueber die Beziehungen zwischen den Monsfelder Seeen und den Mans-
felder Bergbau, 339. — C. Blbmeke. Erzlagerstatten im Odenwald, 340.
— A. Jentzsch. Ueber den artesischen Brunnen in Schneidemiihl, 347. —
K. Endriss. Die geognostische Specialkarte und die geognostische Ueber-
sichtskarte des Konigreichs Wurttemberg, 366. — G. Giirich. Die Kup-
fererzlagerstatte von Wernersdorf bei Iiadowenz in Bohmen, 370. —
B. Lot ti. Die geologiscben Verhaltnisse der Thermalquellen im toscan-
iachen Erzgebirge, 372. — L. Rosenthal. Die metamorphosirende Ein-
wirkung der Basalte auf die Braunkohlenlager bei Cassel, 378. — F. M.
Stapff. Ein paar Worte iiber Bodentemperature und artesische Stromung,
881. — F. Klockmann. Beitrage zur Lrzlagerstattenkunde des Harzes,
385, 466. — R. Lepsius. Die geologische Landesaufnahmen des Grosa-
herzogthuma Hesse, 413. — L. Litschauer. System der ber^baugeolo-
gischen Aufnahmen in Ungarn, 414. — Huyssen. Lagerstattenbilder, 424.
— F. M. Stapff. Was kann das Studium der dynamischen Geologie im
praktischen Leben niitzen, bcsonders in der Berufsthatigkeit des Bauin-
genieura P, 445. — R. Zuber. Die wahrschoinlichen Resultate einer Tief-
bohrung in Lemberg, 471.
Berlin. Zeitschrift fiir praktiache Goologie. 1894. Hefte 1-6.
1894. Purchased.
A. Leppla. Dio geologische Untersuchung des Konigreichs Bayern, 1.
— L. van Werveke. Die geologische Landesuntersuchung von Elsass-
Lothringen, 3. — A. Schraufc Aphorismen iiber Zinnober, 10. — B. Lotti.
Die Kupfererzlagerstatten der Serpentingesteine Toscanaa und deren
Bildung dim- h Diflerentiationsprocesae in Dasischen Eruptivmagmen, 18.
— W. Krebs. Die Bodensenkungen in Schneidemiihl, 19. — R. Wabner.
Die Bodensenkungen in Schneidemiihl und die daraus zu ziehende Nutzen-
wendung, 25. — J# H. L. Vo^t. Ueber die Kieslagerstatten vom Typus
Roros, Vigsnas, Sulitelraa in Norwegen und Rammelsberg in Deutsch-
land, 41, 117, 173. — W. Riemann. Das Vorkommen der devonischen
Eisen- und Mancunerze in Nassau, 50. — A. Stella. Geologische Special-
aufhahme von Italien, 77. — R. Rosenlecher. Die Zink- und Bleierz-
bergbaue bei Rubland in Unter-Karnten, 80. — L. Rosenthal. Setzt die
Saarbriicker Steinkohlenformation unter dem pfalzischen Deckgebirge
fort?, 88. — Hans Reusch. Die geologische Landesuntersuchung Nor-
wegens, 113. — J. Haberfelner. Geologische Verhaltnisse des Erzreviers
von Cinque valli und Umgebungv 134. — F. M. Stapff. Ueber die vor-
geschlagene Entlastung des Schneidemiihler Bohrlocns durch neue Bohr-
locher, 142. — L. Buchrucker. Die Montanindustrie im Grossherzogthum
Baden, 169. — F. M. Stapff. Gold in Schweden, 181.— A. Schrauf. Zur
Erinnerung an Georg Agricola, 218. — A. Gottin^. Die Erzgange zu
Punitaqui in Chile, mit besonderer Beriicksichtigung der Zinnober-
fuhrenden Lagerstatten? 224. — P. Groth. Die Zinkerzlagerstatten von
New Jersey, 230. — G. Schneiders. Borneo in berg-technischer Bezieh-
ung, 233.
Bern (Basel, Geneva, Zurich, &e.). Allgemeine Schweizeriache
Gefiell8chaft fiir dio gesammten Naturwiasenschaften. (Socidto
Helvetiquo dea Sciencea Naturellea.) Vorhandlungen (Actea &c.),
1860-89. 1861-90.
( ). . ( .) ( ), 1890. 1891.
Compte-rendu de la Soci^te* g^ologique Suisae, 125. — E. Bruckner. Daa
Klima der Eiszeit, 141.— A. Penck. Ueber Die Glarner Doppelfalte,
170.
I
I58 ADDITIONS TO THE LIBRARY. [Nov. 1894,
Bern (Basel, Geneva, Zurich, &c). Allgemeine Schweizerische
GeseUschaft fur diegesammten Naturwissenschaften. (Soriete
Helvetique dee Sciences Naturelles.) Verhandluugen (Actes&c),
• 1891. 1892.
M. Musy. Le Canton de Fribourg, 1. — Exotische Blocke im Flysch der
Alpen, 92. — Compte-rendu de la Soci6te* geologique Suisse, 129.
( ). . ( .) ( ),1892. 1892.
Compte-rendu de la Societe* geologique Suisse, 145.
( ). . ( .) ( ), 1893. 1893.
E. Renevier. Geologic des rr<5alpes de la Savoie, 1. — Compte-rendu
de la SociCte* geologique Suisse, 129.
( ). . ( .) Gcschichte der Sohweizerischen
natorforschenden GeseUschaft zur Erinnerung an den Stifr-
ungstag den 6. October 1815 und zur Feier des 50-jtfirigtti
Jubilaums in Gonf, am 21.-23. Augustmonat 1865. (4to,
Zurich.) 1865.
( ). . ( .) Die naturforschende GeseUschaft
in Bern von 18. December 1786 bis 18. Dezember 1886. Bin
RUckblick anf die Gcschichte dieses Vereins bei Anlass der
Feier des 100-jahrigen Bestehons. Von J. H. Graf. (8to,
Bern.) 1886.
( ). . ( .) Neue Denkschriften (Noaveaux
Mdmoirea). Bande xx.-xxix. 1864-85.
( ). . ( .) ( ). Band xxx. 1888-90.
J. J. Frtih. Beitrage zur Kenntniss der Nagelfluh der Schweiz, 1.
( ). . ( .) ( ). Bandxxxi. 1890.
( ). . ( .) ( ). Band xxxiL 1891.
( ). . ( .) ( ). Bandxxxiii.Abth.l.
1893.
R. Emden. Ueber das Gletscherkorn, 1.
( ). . ( .) Comptes-rendus, 1861. 1861.
( ). . ( .) [Archives des 8ci. Fhjs. «*
Nat. Geneve], 1881-90. 1881-90.
(-7-)' • ( •) [: 1 1891. 1891.
Geologie, 76. — H. Schardt. Les Excursions de la Socitlttf g-^ologiq116
Suisse dans les Prealpes Fribourgeoises et Vaudoises, 97.
( ). . ( .) [ ], 1892. 1892.
Minlralogie et Geologie, 62.
( ). . ( .) [ ], 1893. 1893.
Geologie, 66.
. Naturforschende GeseUschaft. Mittheilungen, 1854-S9.
1854-90.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIB BART.
*59
Bern. Naturforschende Gesellschaft. Mittheilungon, 1890. 1891.
J. B. Thiessingf. Notizen iiber den Lias von Lyme Regis, 1. — A.
Baltzer und £. Fischer. Fossile Pflanzen vom Comersee, 139.
-, 1891. 1892.
L. Rollier. Bericht iiber die palaontologischen Sammlungen dee
Naturhistorbchen Museums in Bern, 56. — A. Baltzer. Beitrage zur
Interglaeialzeit auf der Siidseite der Alpen, 88. — A. Baltzer. Der Loss
des St Gallischen Rheinthals, 89. — A. Baltzer. Zur Ilerkunft der
bernlschen bunten Nagelfluh, 91.
, 1892. 1893.
A. Baltzer. Glacialgeologisches von der Siidseite der Alpen, 77. —
T. Studer. Zwei grosse Hunderassen aus der Steinzeit der Pfahlbauten,
87. — L. Rollier. Bericht iiber die palaontologischen Sammlungen des
naturhiatorischen Museums in Bern, 173.
, 1893. 1894.
E. Fischer. Einige Bemerkungen iiber die Oalamarieen-Gattung
Cingtdaria, 1. — E. Kisaling. Nachweis der obern Siisswassermolasse
im Seeland, 15.
. Schweizer Alpenclub. Jahrbuch. 26r Jahrgang. 1892
bis 1893. 1893. Purchased.
S. Simon. Alpine Gipfel-Charaktere, 264. — F. A. Forel. Les varia-
tions pe*riodiques des glaciers des Alpes, 285.
Birmingham. Mason College. Calendar for the Session 1893-94.
1893.
. Midland Naturalist. Vols, xi.-xv. 1888-92. Purchased.
Vol. xvi. 1893. Purchased.
W. H. Painter. The Devonian Hocks of Ilfracombe and Barnstaple,
84, 102.— T. H. Waller. Note on a Rock from Glyn Ceiriog, 201.—
W . J. Harrison. On the Discovery of Molluscan Remains in the
Warwickshire Trias, 227.
. Philosophical Society. Proceedings. VoL viii. Part 2.
1893.
Bombay. Bombay Branch of the Royal Asiatic Society. Journal.
Vol. xviii. No. 49. 1892. 1893.
. . . . No. 49 a (Extra Number). 1894.
. . . . No. 50. 1894.
Bonn. Naturhistori8cher Verein der preussischen Rheinlande, West-
falens und des Regierungsbezirks Osnabruck. Verhandlungen.
49" Jahrgang. Halfte 1 & 4. 1892. Purchased.
Verhandlungen.
Das Ober-Senon von Irnich am Nordrand der Eifel, 1. —
nn. Verzeichniss der im Eisenstein des Lias y von Rittorf
Helmstedt bislang gefundenen Versteinerungen, 107. —
Beitrage zur Kenntniss der Foraminiferen-Fauna des
. — F. T ' inn. Die Lamellibranchiaten des Miocans von
)8. /
Google
i6o
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
KorrespondenzbUitt Iiogen.
V. Ifagens. Das Neanderthal in naturgeschichtlicher Hinsicht, 29.—
K. Konen. Ueber das relative Alter der Ablagerungen im Neanderthal,
31. — Heulsler. Ueber die Kohlensauren-Quellen bei Burgbrohl, 40.--
Fabricius. Geologische Karte der Rheinprovinz Weatfalens etc in
Massst. ^ino, 48. — H. Rauff. Fosailisationsprozess gewisser verkieaelter
Spongien, 61. — H. Rauff. Ueber falschlich fur Fossilien c-ehaltene auf
innere Gesteinsstauchungen zuriickzufuhrende Gesteiusbild unpen, 57. —
E. Lienenklaus. Ostracoden des nordwestdeutschen Tertdars, 58.
Sitzungsberkhte.
H. Pohlig. Ueber das Karbonkonglomerat von Valosine bei Chamounix,
41. — H. Ponlig. Ueber den DryopUheciu, 42. — Heu9ler. Durchbruchdea
Basalts durch die Coblenzschichten des Unterdevons am Scheidskopf, 44.
— H. Pohlig. Fossilien des Devons Australiens, 45. — H. Pohlig. Zinnolxr-
rhomboeder und andere Zinnoberkrystalle von Almaden, 46, 48. — H. Poh-
lig. Bunt angelaufener Saphirkrystall aus dem Basalt des Oelberges, 54. —
H. Pohlig. Fossilien dos Kheinischen Devons, 64. — F. K. Rauff. Ueber
die Organisation und systematische Stellung der Receptaculiten, 59, 74.—
A. Phillippson. Ueber die Kustenforni der Insel Riigen, 63. — H. Pohlig.
DieCemdendesthiiringischen Diluvial travertins, 91. — H. Pohlig. Ueber
den diesiiihrigen Aetna-ausbruch, 91. — S. Stein. Erdbeben in Japan,
94— H. Pohlig. Altpermische Fische, Saurierfahrten u. Medusen der
Gegend von Friedrichrode in Thuringen, 105.— II. Pohlig. JW< syliwtn*
im thiiringischen Travertin, 105.
Bonn. Naturhistorischer Verein der preussischen Rheinlaode, West-
falens und des Regierungabezirks Osnabriick. Verhandlungen.
Jahrgang 50. 1893. Purchased.
Verhandlungen.
B. Sturtz. Ueber versteinerte und lebende Seesterne, 1 . — A. Hosius.
Beitrage zur Kenntniss der Foraminiferen- Fauna des Miocens, 93.—
H. Laspeyres. Das Vorkommen und die Verbreitung des Nickels un
rheinischen Schiefergebirge, 143, 375. — F. Lehmann. Die Lamslh-
branchiaten des Miocens von Dingden, 273. — L. Schulte. Geologised
und petrographische Untersuchung der Umipbung der Dauner Maare,
295. — E. Konigs. Verzeichniss von Petretakten des marinen Ober-
oUgocans aus der Umgegend von Crefeld, 519. — O. Miigge und A. Hosiua
Ueber geschrammte Geschiebe der oberen Kreideformation im Diluvium
bei Miinster i. W., 624.
Korrepjymdvnzbla tt.
Follenius. Ueber die Kohlenf unde in der Eifel, 40.— H. Pohlig. Be-
merkungen uberdie Pflanzenabdrucken dieser Kohlen, 44. — H. Laspeyres.
Einbrucn von alten Eruptivgesteinen in die Flotze der Steinkohlen-
formationen, 47.
Bordeaux. Society Linncenne de Bordeaux. Actes. Vol. xl*«
(Serie 6, Tome v.) 1891-92. 1893.
MSmoires.
H. Arnaud. Profil geologique du chemin de fer, d'Angouleme »
Marmande, region cre"tacee, 11 . — A. Degrange-Touzin. Etude sur la fauna
terrestre, lacustre et fluviatile de l'Oligocene superieur et du Miocene dan*
le Sud-Ouest de la France et principalement dans la Gironde, 125.
Digitized by (j
Vol. 50.]
ADDITIONS TO THE LIBRARY.
l6l
Comptes-rendiu.
A. Degrange-Touzin. Compte-rendu de l'excuraion trimestrielle du
12 avril 1891 a Saint-Me'dard-en-Jalle, xvi. — A. Degrange-Touzin.
Nouveaux fosailea recueillia a Itaton-Durand (commune de Saint-Selve),
xxix. — A. Degrange-Touzin. Corapte-rendu geologique de Texcuraiou tn-
meatrielle du 31 mai 1891, a Monsegur, xli. — E. Benoiat. Compte-rendu
g^ologique de l'excursion faite a l'ooctfliOD de la soixante-treizieme fete
linneenne, liii. — A. Degrange-Touzin. Compte-rendu d'une excuraon
faite dana lea environs du Porfc-Sainte-Marie et d'Aiguillon, cxxii. — A.
Degrange-Touzin. La Catastrophe de Saint-Gervaia (Savoie), sea effeta
et sea causes, cxcvi.
Boston. American Academy of Arts and Sciences. Proceedings.
N. S. Vol. xix. 1891-92. 1893.
. . . N. S. Vol. xx. 1892-93. 1893.
W. Gibbs. Notes on the Oxides contained in Cerite, Samarakite,
Gadolinite, and Fergusonite, 260.
. Boston Society of Natural History. Memoirs. Vol. iv.
No. 11. 1893.
. . Proceedings. Vol. xxvi. Part 1. 1893.
W. Upham. The Origin of Drumlina, 2. — L. S. Griswold. On some
Indian Quarries in Arkansas, 25. — W. Upham. Deflected Glacial Striae
in Somerville, 33.— J. B. Woodworth. On Traces of a Fauna in the
Cambridge Slates, 125.
. . Occasional Papers. IV. Geology of the Boston
Basin, by W. 0. Crosby. Vol. i. Part 1. Nantasket and
Cohasset. 8vo. 1893.
Brunswick. Verein fur Naturwissenschaften. 7er. Jabresbericht,
1889-90 und 1890-91. 1893.
Brussels. Academic Royalo des Sciences, des Lcttres et des Beaux-
Arts de Belgique. Annuairo 1892. 1892.
. . 1893. 1893.
. . Bulletins. Serie 3. Tome xxii. 1891. 1891.
M. Mourlon. Sur la predominance et l'extension des depots de l'^Iocene
suponeur asschien, dana la region comprise entre la Senne et la Dyle, 95.
— M. Mourlon. Sur la position stratigraphique des gites foaailit'eres de
l'Eocene aupSrieur au nord de Glabaia, pr&a de Genappe, 387. — G. Vincent
et J. Couturieaux. Sur lea dtipota de 1 Eocene moyen et supeneur de la
region comprise entre la Dyle et le chemin de fer de Nivelles a Bruxelles,
521.
. . . . Tome xxiii. 1892. 1892.
C. Malaise. De"couverte de la faune fraanienne dans le ba^in de
Nam" 70. — C. Malaise. Sur lea calcaires dtSvoniena do Sonibreffo,
-. . . Tome xxiv. 1892. 1892.
t. Sur de nouveaux gToupea d'osaementa fosailea inatalles
series e royal d'histoire naturelle, 162.
I
l62 .ADDITIONS TO THE LIBRARY. [Nov. 1894,
Brussels. Academie Royale des Sciences, des Lettres et des Beaux-
Arts de Belgique. Bulletins. Serie3. Tome xxv. 1893. 189a
. . Memoires. Tome xlviii. 1892.
. . . Tomel. l^partie. 1891.
. . Memoires Couronne's. (4to.) Tome lii. 1893.
. . . (8v0.) Tomexhd. 1892.
. Societe Beige de Geologie, de Paleontologie et d'Hydrologie.
Bulletin. Tome iv. Fasc. 2 & 3. 1891 & 1892.
B. Dokoutchaief. Notes sur l\5tude scientifique du sol en Ruwie an
point de vue de ragronomie et de la cartographie agricole, 113.—
F. Loewinson-Lessing. Revue bibliographique des nouvelles publi-
cations gtfologiques et paleontologiques russes, 117. — E. Dupont Sur
les principalea donnees que la geologie peut fournir a Pa^culture, 13U.
— A. Rutot et E. de Munck. Piisentation de spongiaires de YiUft
landenien, 151. — A. Rutot. I^es depots phosphates de la Hesbaye, 158.
— A. Issel. Sur le calcaire porphvnque de Rovegno dans la Vallee de la
Trebbia, 160. — A. Petermann. L'exploration cbimique de la terre arable
beige, 167. — E. Dupont. Les pluies dans leurs relations avec des dep't<
g&uogiques bien agfinis, 170. — E. Van den Broeck. Les sources de
Modave et le projet du Hoyoux considdres aux points de vue geologique
et hydrologique, 180. — E. Dupont. Sur rhvdrographie eouterraine dsns
les terrains calcaires, 201. — J. Gosselet. Compte-rendu des excursion*
des 7 et 8 septembre, dans les valines de la Meuse et de la Houille, 216,
221. — V. Dormal. Observations sur une faille du terrain cre'tace' mettant
en contact la craie phosphate avec le tufeau, 240. — L. Dollo. Sur le
Lepidost&us Suesnoniensis, 342. — A. Rutot. Une application de la gt<olo£W
a l'archeologie, 248. — A. Rutot. La constitution de l\5tage paniselien
dans la Flandre occidental, 252.
Mtmoires.
A. Rutot et E. Van den Broeck. Materia ux pour servir a la con-
naipsnnce de la composition chimique des eaux artesiennes du sous-sol de
la Belgique dans leurs rapports avec les couches geologiques qui le*
renferment, 170.— F. Loewinson-Lessing. £tude sur la composition
chimique des roches ^ruptives, 221. — A. Rutot. Les eaux brunes dW
les pints artesiens de Ninove, 227. — J. Felix. Des eaux thermales de
Chaudfontaine (Belgique) et de leur action physiologique et tb£r»-
peutique, 243. — E. de Munck. Note sur les formations quaternaires et
foliennes des environs de Mons, 258. — J. Macpherson. Contribution •
l'e'tude des mouvements mol£culaires dans les roches solides, 26A —
E. Pergens. Nouveaux bryozoaires cyclostomes du cre'tad, 237.—
Rapport au sujet de la Salle de Geologie au Palais du Peuple, 292.
. . . Tome v. Fasc. 1-2. 1891. 1891-92.
Procks-verbaux.
Stanislas Meunier. Sources minerales de l'Australasie, 8. — A. Rutot.
I«e puits artesien de Zulte, 12. — E. Van den Broeck. Afiaissement du
sol de la France, 13. — C. de Vogdt et F. Loewinson-Lessing. Revue
bibliographique des nouvelles publications geologiques et paleontolo*
giques russes, 21, 54.— V. Dormal. Revendication de la priori^
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
163
de la decouverte de poissons dans le caicaire d'Alvaux, 36. — E.
Pergens. Bryozoaires du miocene du Gard, 40. — H. van Cappelle.
Sur les rapports du diluvium entremele' avec le diluvium scanuinave
de Staring et sur un diluvium entremele' dans la Drenthe centmle
(province de Hollande), 69. — E. Dupont. Observations sur l'origine
des rocb.es, 77. — P. Choffat. Comparaison de deux projets de cbemins
de fer a Lisbonne, 84. — V. Dormal. Observations sur l'analogie
que presente la constitution du quaternaire avec les roches sous-
jacentes, 87. — A. Rutot. Sur l'extension des sediments diestiens au
sud de Bruxelles, 88. — C. Malaise. Les Graptolithes de Belgique et
l'6chelle stratigraphique du Silurien, 00. — E. Dupont. La chronologie
geologique dans ses rapports avec les origines des terrains, 97. —
F. Ameghino. L'Homme ibssile Sud-AimSricain, 100. — R. Storms.
Notes sur l'lchthyologie Fossile, 114, 142. — E. Dupont. Re'surae' des
excursions de Mariembourg et do Bomal, 131. — A. Rutot. Note sur un
cas d'application de la GSoiogie aux Travaux Publics, 136, 142 — E. Van
den Broeck. Sur Porigine purement hydro-chimique des minerais de
plomb argentiferes du district de LeadviUe, Colorado, 139. — E. Dupont.
bur l'excursion de la Socidt<$ dans le caicaire carbonifere en 1891,
164, 180. — E. de Munck. Essai sur la concordance probable entre les
difftSrentes assises du terrain quaternaire des environs de Mons et
celles du quaternaire du Nord de la France, 105. — L. Dollo. Les
Pterosauriens, 174. — F. Sacco. Sur l'age des formations ophiolitiques
reoentes, 175. — E. de Munck. Compte-rendu de l'excursion de la
Socie^te" le long du nouveau Canal du Centre a Ville-sur-Haine, Thieu,
Bracquegnies et IIoudeng-Aimeries, 187. — H. O. Lang. Note resumee
sur les quantites relatives du calcium, du sodium et du potassium
comme point de comparaison et moyen de classification des roches
e'ruptives, 192. — C. Bommer. Sur le gite wealdien a v6g6taux de
Bracquegnies, I lain ant , 196. — E. de Munck. Compte rendu de l'excur-
sion faite avec M. Ladriere pour l'Stude du Quaternaire de Ville-sur-
Haine, Thieu, Bracquegnies et Houdeng-Aimeriea, 198.
M&moires.
F. Loewinson-Lessing. Deuxiemo note sur la structure des roches
Gruptives, 3. — A. Erens. Rechorehes sur les formations diluviennes
du oud des Pays-Bas, 14. — C. Bommer. Essai de reconstitution phvsio-
gnomique de quelques types de la tlore houillere, 43. — A. Rutot. Note
sur quelques puits artesiens creuses a Bruxelles, 40. — F. Sacco. L'age
das formations ophiolitiques rdceutes, 60. — F. Beclard. Fossiles nouveaux
du DSvonien inftfrieur de la Belgique, 96. — F. Loewinson-Lessing. Note
sur les taxitea et sur les roches clastiques volcaniques, 103. — F. Standfest.
Les ormes a l'6tat fossile, 109. — O. Lang. Das Mengenverhaltniss von
Calcium, Natrium und Kalium als Vergleichungspunkt und Orduungs-
mittel der Kruptivgesteine, 123. — L. Dollo. Nouvelle note sur le
Champsosaure Rhynchoc6phalien adapts a la vie fluviatile, 147.
Brussels. Socie'tc Beige do Geologic, de Paleontologio et d'Hydro-
logie. Bulletin. Tome vi. Faac. 1-^3. 1893-94.
Procks-verbaux.
E. Dupont. Sur Texcursion de la Soci^te* dans le caicaire carbonifere
en 1891, 7. — L. Dollo. Sur un nouveau type de Dinosaurien, 10. —
M. Bertrand. Les regents progres de nos connaissances orog«5niques,
13. — A. Daimeries. Notes icnthyologiques, 29. — E. Dupont. Les
caraeteres de Involution de la faune quaternaire, 32. — L. Dollo.
L'origine des Kangurous, 37. — A. Rutot. Observations au sujet de
164
ALDin05s 10 IhE LlBEAiT
[Nov. 1894,
la note de M. Ladrifce inthnlee Esaai sur la constitution g^olo^ae da
Terrain Quaternaire de* environs de Mans, 41. — A. Ratot. A proper dee
nouvelles observations fai tea par M. Raevmaekers car le sous-sol de la
Ville de Routers, 43. — A. Rutot et E.' Van den Broeck. K&aliaa
geologiques de* Bondages executes entre BruxeUes et le Rapel par la
Commiasion dee Installations Maritimes de Bruxellea, 53, — £. Dupont.
Un acbe'ina orogenique de la Belgique, 74. — V. DonnaL Sor le de~vocrieai
darts le Baasin de Namur. 70 — E. Dupont. Le giaement des IguanocL^Gf
de Berniss&rt. 86. — L. Dollo. La paleontologie et la theorie de revolu-
tion, 93. — B. DokoutchaierT. Note sur le Loess, 97.— J. L. C. Schroeder
ran der Kolk. Note sur une etude du DiluTium faite aux environs
de Marhelo, pres de Zutphen, 101. — E. de Munek. Observations noo-
velles sur le Quaternaire de la region de Mons, St-SymphorienT
Spiennear 102. — F. Loewinaon-Lesaing. Revue bibliograpbiqoe des
nouvelles publicationa geologiques et paleontologiques russes, 103. —
E. Cuvelier. Compte-rendu d'une excursion dans le calcaire carboniiere
a Pierre-Petru, pres dllastieres, et aux Fosses, sur la Lease, 122. —
E. Dupont. Sur lee concordances cbronologiques entre It* Faunes
Quaternaires et les mceurs des Troglodytes en Perigord et dans la
Province de Namur, 144. — L. Dollo. Sur le baasin du Cbampeoeaure,
158. — L. Dollo. Quest-ce que la geologie?, 159. — C. Bommer. Sur un
noufeau gite de vegetaux decouvert dans largile wealdienne de
Bracquegniea (Hainaut), 100. — L. Dollo. Sur lorigine de la nacreoire
caudale des Ichthyosaurea, 167. — L. Dollo. A quelle epoque geolosriqoe
les profondeurs de l'Ocean ont-elles commence a etre nabitees ?, 1 75. —
E. de Munck. Sur la presence aux environs de Bruxeiles et de Reniiv
de couches Quaternaires, 176. — V. Dornial. Sur les Sables de Li erne ux,
178 — L. Dollo. Premiere note sur les Teleosteens du Cretace superieur
de la Belgique, 180.— F. Sacco. Le Trias dans l'Apennin de l'Emilie,
11*4. — R. Storms. Note sur le Cybium (Enchodut) Bleekeri du terrain
bruxellien, 199. — E. Pergens. Bryozoaires du Senonien de Sainte-
Paterne, de Lavardin et de la Ribochere, 200. — Legende de la Carte
Geologique de la Belgique dressee par ordre du Gouvernement a 1 echelle
du 217.— E. Dupont. LTlomme consider comme force geologique
propre, 241.— L. Dollo. Deuxieme note sur les Mosasauriens de Mesvin,
262.— C. Ubaghs. Origine des vallees de la region du Limbourg, 263. —
A Rutot. Compte-rendu de la Session AnnueUe Extraordinaire de 1892
duns la region volcanique de l'Eifel, 273.
MStnoirea.
R. Storms. Sur le Cybium (Enchodus) Bleekeri du terrain bruxellien,
3. — F. Loewinson-Lessing. Les Ammonees de la zone a Sporadocertu
Munsteri, 15. — C. Ubaghs. Le Megalosaurus dans la Craie Supeneure
du Limbourg, 26. — A. Rutot. Compte-rendu de rexcursion dans le
Quaternaire du Nord de la France et du Sud de la Belgique, 30. — J. L. C.
Schroeder van der Kolk. Note sur une etude du Diluvium faite dans la
region de Marhelo, prea de Zutphen, 73. — E. Van den Broeck. Materiaux
pour la connaisaance des depots Pliocenes supeneurs rencontres dans lea
derniers travaux de creusement des Bassins Maritimes d'Anvers, Bass in
Africa (ou Lefebvre) et Baasin America, 86. — C. Ubaghs. Sur lorigine des
vallees du Limbourg hollandais, 150.— E. Dupont. Les calcaires et
achistes fraaniens dans la region de Frasne, 171.— L. Dollo. Nouvelle
note but l'osteologie des Mosasauriens, 219.
Brussels. Society Beige de Geologic, de Paleontologie et d'Hydro-
logie. Bulletin. Tome vii. Fasc. 1-3. 189&-94.
Proch-verbaux.
E. Van den Broeck. fitude sur le Dimorphiame dea Forainiiiiferes et
Vol. 50.J
ADDITIONS TO THE LIBRARY
des Nummulites en particulier, 6. — E. Lagrange. Les Terrains Calcaires
et les explorations des Cavernes, 42, 82. — A. Rutot. Le gisement des
Ores de Gobertange, 67. — L. Luyckx. Note sur le gres calcareux blanc
du Luxembourg, gisement de Montourdons (Ethe), 71. — F. Sacco. Con-
tribution a la connaissance paleontologique des argiles ecailleuses et des
schistes ophiolitiques de 1 Apennin septentrional, 78. — L. Dollo. Sup-
pression du genre Leiodon, 79. — L. Dollo. Champsosaurus et Pareia-
saurus, 79.— L. Dollo. Le Dante et la connaissance de la Terre, 79. —
A. Rutot Les puits artesiens do la region N.O. de Bruxelles, 80. —
L. Dollo. Nouvelle note sur les Poiasons de la ( 'rnie phosphatide, 93. —
L. Dollo. Les ancetres des Mosasaures, 93. — A. Rutot Note sur la
decouverte d'une deTense de Mammouth dans les alluvions anciennes de
la Meuse, a Smeermaas, 94. — A. J. Bourdariat. Esquisse geologique et
mine'ralogique du district aurifere de Santa-Cruz (Honduras), 111. —
X. Stainier. De la presence du sel marin dans quelques types de limon,
118.— E. Van den Broeck. Recherche d'eaux souterraines a Anvers,
124. — T. C. Moulan. Observations sur les relations pouvant exiater entre
la composition chimique des eaux et leur temperature d'une part et leur
mode de circulation souterraine d'autre part, 131. — C. Francois. Le
regime des eaux de la region de Dombasile-sur-Meurthe, notaniment dans
les calcaires marneux du terrain secondaire, 132. — E. Van den Broeck.
Le puits artesien du peignage de laines d'Hoboken, 143. — X. Stainier.
L'hydrologie envisaged au point de vue de ragriculture, 148. — A. Rutot.
Note sur l'extension dutongrien superieur vers Bruxelles, 159. — X. Stainier.
Note sur une breche phtaniteuse et sur des gres Wanes du Ilouiller
infemeur, 173. — X. Stainier. Marbre rouge a Cnnoides dans le famennien
de 3a Lesse, 177. — X. Stainier. Notes sur le Ilouiller de Belgique, 178.
— )w. Stainier. Age de quelques argiles des environs de Fleurus, 182. —
X. Stainier. Le bruxellien de la Province de Namur, 180. — E. Lagrange.
Lea terrains calcaires et les explorations des cavernes, 189. — C. Reid.
Etude sur la geologie neo-tertiaire, 193. — X. Stainier. Note sur les
Sauriens jurassiques beiges, 201. — F. Sacco. Sur quelques Tinoporina du
mioeene de Turin, 204. — E. Van den Broeck. Observations dans la
region oligocene des environs de Louvain, 207.
M&moires,
F. Sacco. Contribution a la connaissance paleontologique des Argiles
ecailleuses et des Schistes ophiolitiques do 1' Apennin septentrional, 3. —
A. J. Bourdariat. Esquisse geologique et mine'ralogique du district
aurifere de Santa-Cruz, Honduras (Amerique Centrale), 35. — II. Pohlig.
Le premier crane complet du Rhinoceros ( Camopus) occidentalism Leidy,
41. — C. E. Bertrand. Conferences sur les charbons de terre, 45. —
A. Daubree. Report on Deep-sea Deposits, bv John Murrav and
A. F. Renard, 83. — John Murray et A. If, Renara. Notice explicative
de la carte des sediments de mer profonde, 109. — X. Stainier. Materiaux
pour la faune du houiller de Belgique, 135.
Brussels. Societo Beige do Geologie, de Paleontologio efc d'Hydro-
logio. Bulletin. Tome viii. Fasc. 1. 1894.
Procte-verbaux.
E. Putzeys. Les sources des Vallees de TOurthe, du Hoyoux et
du Bocq, 0. — A. Rutot. Compte-rendu de la course faite le 21 janvier
dans la Vallee du Bocq, 43. — L. Dollo. L'Origino du Chameau, 49. —
X. Stainier. Un Spiraxis nouveau du DtSvonien de la Belgique, 52. —
A. Rutot. Resultats d'observations g6ologiques le long du littoral, 53. —
A. Rutot. Sur rechelle stratigraphique du Landeuien, 53. — L. Dollo.
L'lchthyosaure d'Arlon, 75. — A. Lechien. Sur la decouverte d'un
Ichthyoaaure de grande taille a Arlon, 76. — Walin. Etude sur le Regime
1 66 AUDITIONS TO THE LIBRARY. [NoV. 1 894,
hydrologique, sur l'importance et la nature des eaux dans les terrains
calcaires du Uondroz et de rEntre-Sambre-et-Meuse, 90.
Mfanoire*.
X. Stainier. litude aur le Baasin Houiller d'Andenne, 3. — X. Stainier.
Un Spirtucis nouveau du Devonien Beige, 23. — A. Rutot. Apercu sur la
geologie de la Cote Beige, 29.
Brussels. Society Malacologique de Belgique. Aiinales. Tome
xv. 1880. Fasc. 2. 1880. 1891.
. . . Tomexxvi. 1891. 1892.
M. Cossmann. Catalogue illustre* des coquilles fossilas de l'eocene de*
environs de Paris, 6e fascicule et supplement, 3. — E. Vincent. Con-
tribution a la paleontologie de l'eoc5ne beige, 162.
Bulletin.
D. Raemaekers. Note sur la faune malacologique des depots modern*
observes a Bruxelles, vii. — G. Vincent. Observations relatives a l'ap
accorde' aux sables ferrugineux des -collines des Flandres, xix. — Af.
Mourlon. La derniere butte de sable de l'avenue Louise (Bruxelles),
xxiii. — X. Stainier. Decouverte de la faune givetienne a Emines, xxxiii.
— J. Couturieux. Note sur le quaternaire ancien du nord-ouest de Is
Belgique, xxxvi. — G. Vincent. Rectification relative a une prttendue
comparaison de la faune du systeme ledien avec celle du calcaire grosser
nioyen du bassin de Paris, xlii. — E. Vincent. Observations sur u Gti-
bertia iiwpinata, Mor.," lii. — M. Cossmann. Reponse aux observations de
M. E. Vincent sur le 44 Gilbertia inopinata, Morlet," lxiv. — A. Daimeries.
Notes Ichthyologiques, lxxii.— M. Mourlon. Les dernieres buttes de
sables du \V ijngaerd Beig a Test de Bruxelles, lxxx. — E. Vincent. A
propos de l'origine du limon supeneur, lxxxiv. -E. Vincent Description
d'une couvelle espece de " PholadicUe " des environs d'Anvers, lxxxn.
— Al. Mourlon. Sur le classement stratigraphique des dopSts de l'^tage
asschien dans la sene tertiaire, a propos d'un mtiinoire de MM. G. Vincent
et Couturieux, xci.
Buckhurst Hill. Essex Field Club. Essex Naturalist. Vol vii.
Nos. 6-12. 1893.
H. W. Monckton. Geological Notes in the Neighbourhood of Onpar,
Essex, 87.— H. W. Monckton. On the Gravels near Barking Side,
"Wanstead, and Walthamstov*, Essex, 115.
Budapest. Magyar Foldtani Tarsulat. (Ungarische geologische
Gesellschaft.) Foldtani Kozlony. Kotet xxii. Fiizet 1-12.
1892.
K. von Murakozy. A nagymihalyi rhyolith-trachytok elmallasa, L—
S. Gesell. Bamaszen es tdzeg Arvamegz6b«n, 17. — K. v. Murakozy.
Ueber die Verwitterung der Rhyoiith-Trachyte von Nagy-Mihaly, oU—
A. Franzenau. A bradi aranglelet, 80.— G. Teglas. A vulkoii
banzaszat bsiniveletei, 82.— A. Franzenau. Ueber den grossen Freigold-
fund aus der Umgebung von Brad, 119. — G. Teglas. Die alten Gewerke
des Bergbaues von Vulkoj, 122.— Festsitzung der ungariscben ceolo-
gischen Gesellschaft vom 6. April 1892 zur Feier des 70. Geburte-
tages ihres Prasidenten Prof. Dr. J. von Szabo, 137, 187. — F. Schafarok.
Szabo Jozsef es a magyar geologia, 139.— B. von Inkey. Szabo Joaef
Digitized by Google
Vol 50.]
ADDITIONS TO THE LIBRARY.
167
munkdja Selmeczrol, 147. — G. Petho. Ctiatlkea Szabtii, uj kagylo faj a
p^tervardi hegyseg hypersenon r^tegeibbl, 15.'?. — G. Halavats. A hercze-
ghalnii arte"zi kiit, lfili. — F. Schafarzik. Josef v. Szabd und die ungarische
Geologie, 188. — B. von Inkey. Szabo's Werk iiber Selmecz, 190. — J.
Petho. Cucull<?a Szab6if eine neue Muschelart aus den hypersenonen
Sehichten des Gebirges von P^tervdrad, HML — K. Zimanyi. Asvanytani
kozlenienyek, 22a. — L. Litschauer. A femes dsvanyok telepeinek ercze-
sedes viszonyai, 284. — M. Urbdn. Tapasztalatijegyzetek a liegygerincz-
vonalak 6s a telerek csapdsdrol, 24o. — K. Ziinanyi. Mineralogische
Mittheilung, 267- — L. Litschauer. Vertheilung der Erze in den Lager-
statten metallischer Mineralien, 222. — M. Urban. Erfahrungsdaten
iiber das Streichen der Gebirgsriicken und der Erzganjye, 2!lIL — G.
Szddeczky. Adatok az erd«51yi Erczhegyseg eruptiv kozeteinek ismerte-
tlselit'z, 2&L=F. Schafarzik. Az 1887. ds 1888. evi magvarorszagi fol-
drengesekol, SQL — J. von Szadeczky. Zur Kenntniss der EJruptivgesteine
des siebenbiirgischen Erzgebirges, 323. — F. Schafarzik. Bcricht iiber die
ungarischen Erdbeben in den Jabren 1887 und 1888, 33L.— J. Loczka.
Adatok a pyrit chemiai constitutiojanak ismeretchez, 868. — A. Koch.
Az 1888. en erdelvi foldrengesekrbl, :fci8.— M Kispatic. Az 1887. es
1888. 6vi horvat-szlavondalmatorszdgi, valatnint a bosnydkherczegovinai
foldrengesek, 868.- — S. Kalecsinszky. Egyszerii, foldrengtfstjelzo k^szii-
16krcil, 377.— -J. Loczka. Beitrage zur Kenntniss der cnemischen Con-
stitution des Pyrits, 88'.). — A. Koch Ueber die siebenbiirgischen Erd-
beben ira Jahre 1888, 394. — M. Kispatic. Bericht iiber die Kroatisch-
slavonisch-dalmatinischen, sowie iiber die bosnisch-herzegovinischen
Erdbeben in den Jahren 1887 u. 1888, 400. — A. von Kalecsinszky. Ueber
ein einfaches Quecksilber-Seismonieter, 415.
Budapest. Magyar Foldtani Tarsulat. (Ungarische geologische
Gesellschaft.) Foldtani Kozlony. Kotet xxiii. Fiizot 1-12.
1893.
R. Franze\ A ganoczi mesztufdbau talalt Confervites mikroszkopos
vizs^alata, 4, — G. Teglds. A roniaiak kobdnyaszata Potaissa vagyis a
mai Torda kozeleben, 13. — R. Franze\ Die mikroskopische Untersuchung
der u Conferviten * aus dem Kalktufte von Gdn6cz, 7_L — G. Te"glas. Die
romischen Steinbriiche in der Nahe von Potaissa oder des heutigen Torda,
79. — E. Schmidt. Kristalytani vizsgdlatok, 97. — T. Posewitz. A.
szentgali cseppkobarlang, 104. — A. Schmidt. Krystallograohische Unter-
suchungen, laBL — M. Staub. A ganoczi mesztufalerakodas flordja, 1G2.
— M. Staub. Die Flora des Kalktuffes von Ganocz, 21flL — B. Lengyel.
A kolopi k«mes forrds, 2iiL — J. Nuricsdn. A tordai sosforrasok chemiai
elernzese, 2114. — G. Teglas. A Fejer-Korbsvidrik ielentose'ge a romaiak
bdnya-administratiojaban, 222. — B. von Lengyel. Die Schwefelquelle von
Kolop, 2113. — J. Nuricsdn. Die chemische Analyse der Salzquellen von
Torda, 29J1 — G. Tdglas. Die Bedeutung der Umgebung der Fejer-
Koriis in der Bergadministration der Romer, 298, — S. Schmidt. Czin-
kota geolojriai viszonyai, 329.— M. Staub. Adalek a Bacillariaceak
stratigiaphiai jelentoseg^hez, 348. — 0. Schmidt. Die geologischen
Verhaltnisse von Czinkota, 875. — M. Staub. Kin Beitrag zur strati-
graphischen Bedeutung der Bacillarien, 390.
. . ( .) . Kbtet xxiv. Fiizet 1=5. 1894.
L Lorenthey. Kurd tolnamegyei helys^g pontusi faunaja, 2. — G.
Halavats. Miskolcz varosa fiildtani viszonyai, 18. — A. Franzenau.
Markusevec (Zagrab kornydki) i-fosszil foramikiferak, 23. — E. Lbrenthey.
Die pontische Fauna von Kurd im Comitate Tolna, 73, 148. — J. Halavdts.
Die geologischen Verhaltnisse der Stadt Miskolcz, 88. — A. Franzenau.
vol. L
0
1 68 ADDITIONS TO THE LIBRARY. [Nov. 1 894,
Fossile Forarainiferen von Markusevec aus der Umgebung Agram?, 92.—
A. Koch. Uj adotok a gyalui havasok foldtani szerkeset£nek ponto^abb
ismeretdhez, {j8* — R. Francd. A. Balaton iszapjarol, 111. — I. Lbrenthej.
Kurd Tolnamegyei helyse*g pontuei faunaja, UiL — A. Koch. Neae
Beitriige zur genaueren geologischen Kenntniss dee Gyaluer Hochge-
birges, 135. — H. France. Ueber den Schlamm dee Plattensees, 142.
Budapest. Magyar Kirrilyi. Foldtani Interzet. (Kon. Unga-
rische geologische Anstalt.) Jahresbericht fiir 1891. 1S93.
( .) Mittheilungen aus dem Jahrbnch.
Bandx. Heft© 1^5, 1892.
G. Primics. Die Torfla^er der Siebenburgtechen Landestheile, 1.—
J. Halavats. Palaeontologische Daten zur Kenntniss der Fauna der
siidungarischen Neogen-Ablagerungen, 25, — B. von Inkey. Geologiscb-
ajjronomische Kartirung der Umgebung von Puszta-Szt.-Lorincz, 4" —
E. Lorenthey. Die oberen pontischen Sedimente und deren Fauna ba
Szegzard, Nagv-Manyok und Arpad, ZL — T. Fuchs. TertiarfosBilien
aus den kohlenfiihrenden Miocanablagerungen der Umgebung yon
Krapina und Hadoboj, und Uber die Stellung der sogenanuten u Aquita-
niscben Stufe," 16L
( .) Dritter Nachtrag zum Katalog der
Bibliothek. 1889-1891. 1892.
Buenos Aires. Instituto Geogrdfico Argentino. Bole tin. Tomosiii.
Cuadernos 10-12. 1892.
. . . Tomo xiv. Cuadernos 1-12. 1893-94.
C. Albert. Neuquen, ISA— J. B. Ambrosetti. Viaje a la Pampa Central,
!292. — J. B. Ambrosetti. Contribucion al estudio de las tortugaa fluvialt*
oligocenas de los terrenos terciarios antiguos del Parana, 489.
. Sociedad Cientffica Argentina. Anales. 1893. Tomo
xxxv. Entregas 2 & fL 1893.
V. Novarese. Ix>e vacimientoa aurfferos de la Puna de Jujuy,
J. C. Thierry. Combustibles Minerales, 1 IS— J, C. Thierry. X^ta
sobre la formacion del Carbon de Piedra, 123. — M. Senoret La Region
Aurifera en la Tierra del Fuego, 243.
. . . 1893. Tomoxxxvi. Entregas 1_& 2. l^3-
A. Mercerat. Contribucion a la geologia de la Patagonia, 6&
Caen. Societe Linncenne de Normandie. Bulletin. Serie i
Vol. vi. Annee 1892. Fasc. 4. 1893.
A. Bigot. Sur la feuille d'Alencon de la Carte Geologique de France,
285.
SerioiL Vol. vii. 1893. Fasc. 1 & 2, 18i&
A. Bigot. Sur les buttes de Montraye\ 2Q.— L. Lecornu. Sur le Mineral
de Fer de Feuraerolles-Sai nt- Andre , 37.— L. Brasil. Note sur le 1^
sup<Srieur du Calvados,
Memoires. Vol. xvii. Fasc 2 & 3, 1893.
A. Bicrot. Contributions a l'dtude de la Faune Jurassique de ^or"
maudie, IE Memoire. Sur les Trigonies, 259.
by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
169
Calcutta. Asiatic Society of Bengal. Journal. New Series.
Vol. lxi. Part 2, No. & 1892. 1893.
. . . . Vol. lxii. Part 2. Nos. 1-4.
1893. 1893 -94.
T. H. Holland. The Petrology of Job Charnock's Tombstone, —
T. IL Holland. On a slab of Chinese agglomerate-lava bearing a Chinese
inscription, discovered in St. John's Churchyard, Calcutta, 1(14.
. . Proceedings. 1892. No. HL 1893.
. . . 1893. Nos. 1-10. 1893-94.
W. King. Note on flaked and chipped stones from Kon in the
M irzapur District, 52,
. . . 1894. No. L 1894.
. . Annual Address by the President (Sir C. A. Elliott).
1894.
Cambridge. Cambridge Philosophical Society. Proceedings. Vol.
viii. Part 2. 1894.
A. C. Seward. On a new Fern from the Coal Measures, 4L — F. 11.
Cowper Reed. Abnormal Forms of Spiri/era lincata (Martin) from the
Carboniferous Limestone, dL
. . Transactions. Vol. xv. Part 4, 1894.
Cambridge, Mass. American Academy of Arts and Sciences.
Memoirs. Vol. xii. No. L 1893.
. Museum of Comparative Zoology at Harvard College.
Annual Report of the Curator for 1892-93. 1893.
. . Bulletin. Vol. xvi. Nos. 13 & LL 1893.
G. P. Merrill. Report upon rocks collected from the Galapagos
Wands, 235. — L. S. Griswold. A Basic Dvke in the Connecticut Triassic,
2119.
. . . Vol. xxiv. Nos. 4-7. 1893.
. . . Vol. xxv. Nos. 1=1L 1S93-94.
. . Memoirs. Vol. xiv. No. 3. 1893.
Cardiff. South Wales Institute of Engineers. Proceedings. Vol.
xviii. No. iL (See also Swansea.)
Cfa icago. Journal of Geology. Vol. L Nos. 3-8. 1893.
L C. Russell. Malaspina Glacier, 219. — G. IL Stone. The Osar
Gravels of the Coast of Maine, 240. — T. C. Chamberlin. The horizon of
Drumlin, Oscar and Kame Formation, 255. — 11. L. Smyth. A contact
between the Lower Huronian and the underlying Granite in the Republic
Trough, near Republic, Michigan, R. A*. F. Penrose, Jun. A Pleis-
tocene Manganese Deposit, near Golconda, Nevada, 215. — 11. S. "Williams.
o2
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
The elements of the geological time-scale, 283. — F. D. Adams. On the
typical Laurentian Area of Canada, 325. — A. Osano. Melilite-Nephe-
line-Basalt and Nepheline-Basanite from Southern Texas, 341. — C. R-
Van Hise. Some Dynamic Phenomena shown by the Bamboo Quartxite
Ranges of Central Wisconsin, 347. — R. A. F. Penrose, Jun.— The
chemical relation of Iron and Manganese in Sedimentary Rocks. 3oC —
H. B. Kummel. Some Rivers of Connecticut, 371. — I. C. Russell
Geological history of the Laurentian Basin, 394. — \V. S. Bayley. The
Basic Mjissive Rocks of the Lake Superior Region, 433. — R. A. F.
Penrose, Jun. Notes on the State exhibits in the Mines and Mining
Building at the World's Columbian Exposition, Chicago, 457.— G. H.
Stone. The Las Animas Glacier, 471. — B. Willis. Conditions of Sedi-
mentary Deposition, 476. — J. Le Conte. Theory of the Origin of
Mountain Ranges, 642. — A. Harker. On the Migration of Material
during the Metamorphism of Rock-Masses, 574. — A. C. Lawson. The
CordiUeran Mesozoic Revolution, 579. — W. S. Bavley. Sketch of the
f resent state of knowledge concerning the Basic Massive Rocks of the
<ake Superior Region, 587, 688. — O. A. Derby. A study in consanguinity
of Eruptive Rocks, 597. -J. P. Iddings. A Dissected Volcano of
CrandaU Basin, Wyoming, 606. — A. VVinslow. Notes on the Lead and
Zinc Deposits of the Mississippi Valley and the Origin of the Ores, 61 2.—
C. D. W alcott. Geologic Time, as indicated by the Sedimentary Kocks
of North America, 639.^J. J. Stevenson. "On the Origin* of the
Pennsylvania Anthracite, 677.— W. II. Hobbs. On the Geological
Structure of the Mount Washington Mass of the Taconic Range, 717. —
J. C. Branner. The supposed Glaciation of Brazil, 763. — IL Backstrom.
Causes of Magraatic Differentiation, 773.— W. H. Hobbs. The Geo-
logical Structure of the Housatonic Valley lying east of Mount Washing-
ton, 780.— F. P. Gulliver. The Newtonville Sand-plain, 80S— F
Brascom. The Structures, Origin, and Nomenclature 01 the Acid Vol-
canic Rocks of South Mountain, 813.— J. P. Iddings. Genetic Relation-
ships among Igneous Rocks, 813.
Chicago. Journal of Geology. Vol. ii. Noa. 1-3. 1894.
G. H. Williams. The Distribution of Ancient Volcanic Rocks along
the Eastern Border of North America, 1. — J. S. Diller. Revolution in
the Topography of the Pacific Coast since the Auriferous Gravel Period,
32. — G. K. Gilbert and B. S. Lyman. The name " Newark " in American
Stratigraphy, 55. — C. S. Beachler. An abandoned Pleistocene River
Channel in Eastern Indiana, 62.— W. M. Davis. Physical Geography »
the University, 66. — A. M. Hansen. The Glacial Succession in Norway,
123.— H. S. Williams. Dual Nomenclature in Geological Classification,
145, — W. B. Clark. Origin and Classification of the Greensands of New
Jersey, 161.— C. R. Keyes. The Nature of Coal Horizons, 178.-J-.f-
Smitn. The Arkansas Coal Measures in their relation to the Pacibc
Carboniferous Province, 187.— T. C. Chamberlin. Pseudo-Cols, 20<>.—
W. H. Hobbs. Note on the English equivalent of Schunoenstruktur,
206. — W. Window. Geological Surveys in Missouri, 207.— H. M.
Cadell. The Oil-Shales of the Scottish Carboniferous System, 243.-
L. F. Ward. The Cretaceous Rim of the Black Hills, 250.— C. Wiman.
On Diployraptid*, Lapworth, 267.— E. A. Smith. Geological Survey in
Alabama, 276— R A. F. Penrose, Jun. The Superficial Alteration of
Ore Deposits, 288.— J. A. Udden. Erosion, Transportation, and Sedi-
mentation performed by the Atmosphere, 318.
.••
Christiania. Nyt Magazin for Naturvidenskaberne. Vol.
Nos. 4 & 5. 1893.
Digitized by Go< |
Vol. 50.]
ADDITIONS TO THE LIBRARY.
Christiania. Nyt Magazin for Natunridenskaberne. Vol. xxxiv.
Nos. 1 & 2. 1893.
O. E. Schiatz. Nogle lagttagelser over Isens Bevaegelse i Fieldstrsek-
ningen ostenfor Stoisjoen i Rendalen, L — O. E. Schi0tz. Om Oiegneisen
i Sparagmitfjeldet, 7. — P. A. Oyen. Isbraestudier i Jotunheimen, 12. —
A. M. Hansen. Om beliggenheten av braeskillt t og forskellen mellem
kyst- og kontinental-siden hos den skandinaviske storbrae, 112.
Cincinnati. Society of Natural History. Journal. Vol. xv.
Nos. 1&2. 1892.
J. F. James. The Preservation of Plants as Fossils, 75. — S. A. Miller
and C. Faber. Some new Species and new Structural Parts of Fossils,
79. — J. F. James. Manual of the Palaeontology of the Cincinnati Group,
Part III., 88. — D. T. D. Dyche. Remarks on the Stems and Roots of
Crinoids from near Lebanon, Ohio, 101.
. . . Vol. xvi. Nos. 1-4. 1893-94.
J. F. James. Studies in Problematical Organisms : No. II. The Genus
Fucoides, 02. — J. F. James. Remarks on the Genus Arthrophycus, Hall,
82. — J. F. James. Fossil Fungi, 94.— G. P. Grimsley, Mineral Synthesis^
157. — J. F. James. Manual of the Palaeontology of the Cincinnati
Group, 178.
Colombo. Cevlon Branch of the Royal Asiatic Society. Journal.
Vol. xi. "No. 41. 1890. 1894.
. . . Vol. xiii. No. 44. 1893. 1894.
. . Proceedings, 1888-90. 1894.
Copenhagen. Kongelige Danske Videnskabernes Selskab. Over-
sigt 1892. No. 3. 1893.
. . Oversigt 1893. Nos. 1-3. 1893-94.
. . 1894. No. 1. 1894.
. . Naturvidenskabclige og Mathematiske Afhandlinger.
Serie 6. Tome vii. No. 7-9. 1892-93.
. Universitet8 Zoologiske Museum. E Museo Lundii.
Band ii. FoTste Halvbind. 1893.
Cordova. [Buenos Aires.] Academia Nacional de Ciencias en
Cordoba, Republica Argentina. Bolotin. 1890. Tomo x.
Entrega 4. 1890.
J. 13. Ambrosetti. Observaciones sobre los Reptiles fosiles oligocenes
de los terrenos terciarios del Paranfi, 409. — L. Harperath. Sobre la com-
posicion quimica de las sales de las salinas del interior de la Republica
Argentina, 427. — R. Zuber. Informe sobre el petroleo de la Laguna de
la Brea, 442.— R. Zuber. Estudio geologico del Cerro de Cacneuta y
sus contornos, 448.
Cracow. Akadcmja Umiejetosci. Rosprawy. Wydziat matema-
tyczno-przynodniczy. Serya 2. Tom. iv. 1893.
. . . . Serya 2. Tom. v. 1893.
— . . . Tomcvi. 1893.
M. Raciborski. Cycadeoidea Niedzwiedzkii, no v. sp., 301.
172
ADDITIONS TO THE LIBRARY,
[Nov. 1894,
Darmstadt. Verein fur Erdkundo und der Grossheasischen geo-
logischen Landesanstalt. Notizblatt. IV. Folge. Heft 14.
1893.
C. Chelius. Analysen der geologischen Landesanstalt zu Darmstadt,
1. — C. Chelius. Geologiecher Aufnahme-bericht iiber Blatt Neunkirchen
i 0., 3. — G. Klemm. Gletscherspuren im Spessart und ostlichen Oden-
wald, 9.
. See Books : Hesse.
Davenport, Iowa. Davenport Academy of Natural Science. Pro-
ceedings. Vol. v. Part 2. 1885-89. 1893.
Dijon. Academic des Sciences, Arts ct Belles-Lettres. Me'moires.
Serie4. Tome Hi. 1892. 1892.
J. Martin. Des Eaux de la ville de Dijon et des moyens d'en aug<-
menter considdrablement le dSbit, 493.
Dorchester. See Sherborne.
Douglas. See Ramsey.
Dresden. Naturwissenschaftliche Gesellschaft Isis. Sitsungs-
bericht und Abhandlungen, Jahrgang 1893. Januar bis JunL
1893.
Abhandlungen.
A. B. Meyer. Wurde Bernstein von Ilinterindien nach dem Wcsten
exportirt ?, 63.
. Verein fur Erdkunde. XXIII. Jahresbericht. 1893.
Dublin. Royal Dublin Society. Scientific Proceedings. X. S.
Vol. viii. Parts 1 & 2. 1893.
A. Harker. The Use of the Protractor in Field-Geology, 12. — W. J.
Sollas. On Pitchstone and Andesite from Tertiary Dykes in Donegal, 87.
— W. J. Sollas. On the Variolite and associated Igneous Rocks of
Roundwood, Co. Wicklow, 94. — G. A. J. Cole. On Hemitrypa hibernic<i,
M'Coy, 132. — R. J. Moss. On a Graphitic Schist from Co. Donegal, 200.
. . Scientific Transactions. Series 2. Vol. v. Nos.
1-4. 1893.
. Royal Irish Academy. Proceedings. Series 3. Vol. ii.
Nos. 4 & 5. 1893.
A. Bell. Notes on the Correlation of the Later and Post-Pliocene
Tertiaries 011 either side of the Irish Sea ; with a Reference to the Fauna
of the St. Erth Valley, Cornwall, 620.— J. Thomson. On the Genera
CalophyUum and Camjwphyllum, 667.
. . . . Vol. iii. Nos. 1 & 2. 1893-94.
V. Bali. On the Volcanoes and Hot Springs of India, and the Folk-
Lore connected therewith, 151.— J. P. A. O'Reilly. Notes on Litho-
thamnion met with in Deep Cuttings at the mouth of the River Lifley,
223.
. Transactions. Vol. xxx. Parts 5-12. 1893-94.
A. 0. Haddon, W. J. Sollas, and G. A. J. Cole. On the Geologv of
Torres Straits, 419.— W. J . Sollas. On the Volcanic District of Carling-
ford and Slieve Gullion : Part I., 477.
Digitized by
Vol. 50.]
ADDITIONS TO THE LIBRARY.
173
Dublin. Irish Naturalist. Vol. i. 1892. Purchased.
G. A. J. Cole. County Dublin, Past and Present, 9, 31, 53, 73, 90.—
R. F. Scharff. Perforations in Carboniferous Limestone, 118. — R. Lloyd
Praeger. The Irish Post-Glacial Estuarine Deposit, 138. — G. H. Kinahan.
Quartzite9 and Quartz-rocks, 102, 184.
. . Vol. ii. Nos. 1-12. 1893. Purchased.
Mary K. Andrews. Denudation at Cultra, Co. Down, 16, 47. —
W. Swanston. The Silicified Wood of Lough Neagh, 63, 102. — T. Far-
rington. The Magnesian Limestone of the Cork District, 135. — G. A. J.
Cole. The Beauty and Use of Irish Building-Stones, 168, 179. — J. Porter.
Magnesian Limestone in the Neighbourhood of Cork, 221. — G. II. Kina-
han. The Scalp, Co. Dublin, 241.
. . Vol. iii. Nos. 1-6. 1894. PurcJutsed.
W. J. Sollas. A walk along the Glacial Cliffs of Killiney Bay, 13.—
R. L. Praeger. Palaeontological Notes on the Glacial Deposits of Killiney
Bay, 17.— S. M. Thompson. A Plea for Irish Glaciology, 30— W. H.
Patterson. Shell-mounds at Rosapenna, North Donegal, 49. — James
Bennie. Possible Arctic Plant-Beds in Ireland, 72. — R. M. Young. On
a recent find of Irish Elk-bones, &c. in Belfast, 81. — Mary K. Andrews.
Dykes in Antrim and Down, 93. — T. Mellard Reade. The High and
Low-lovel Shelly Drifts around Dublin and Bray, 117.
Easton, Pa. (New York). American Institute of Mining Engineers.
Transactions. Vol. viii. 1879-80. 1880.
. . . Vol. xi. 1882-83. 1883.
. . . Vols, xiii.-xix. 1884-91. 1885-91.
. . . Vol. xx. 1891. 1892.
C. E. Hall. Geological Notes on the Manganese Ore-Deposit of Cri-
mora, Virginia, 46. — C. M. Rolker. The Alluvial Tin-Deposits of Siak,
Sumatra, 50. — T. A. Rickard. The Mount Morgan Mine, Queensland,
133.— T. D. Ledyard. Some Ontario Magnetites, 172.— H. B. 0. Nitze.
Notes on some of the Magnetites of South-western Virginia and the con-
tiguous territory of North Carolina, 174. — 11. H. Stock. Notes on the Iron-
ores of Danville, Pennsylvania, with a description of the Longwall method
of Mining used in working them, 369. — \V. A. Thacher. Mining in
Honduras, 394.— G. H. Eldridge. The Florence Oil Field, Colorado, 442.
— T. A. Rickard. The Bendigo Gold Field, 463.
. . . Vol. xxi. 1892-93. 1893.
C Heinrich. Zinc-blende Mines and Mining near Webb Citv, Mo., 3.
— S. F. Emmons. Fluorspar- Deposits of Southern Illinois, 3i. — T. A.
Rickard. La Gardette: The Historv of a French Gold Mine, 79. —
E. C. Moxham. The < Great Gossan Lead » of Virginia, 133.— W. B. M.
Davidson. Notes on the Geological Origin of Phosphate of Lime in the
United States and Canada, 139. — \V. P. Blake. Contribution to the
Early History of the Industry of Phosphate of Lime in the United States,
157. — W. P. Blake. Association of Apatite with Beds ot Magnetite, 155).
— T. M. Chatard. Phosphate Chemistry as it concerns the miner, 160. —
J. Stewart. Laurentian Low Grade Phosphate-ores, 176. — W. B. Phil-
lips. A List of Minerals containing at least one per cent, of Phosphoric
Acid, 188. — G. H. Eldridge. A Preliminarv Sketch of the Phosphates
of Florida, 196.— T. Ulke. A new Tin Mineral in the Black Hills, 240.
— G. F. Kunz. Bohemian Garnets, 241. — N. L. Britton. Note on a
174
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
Collection of Tertiary Foeail Plants from Pototf, Bolivia, 250 — H. B. C.
Nitze. The Magnetic Iron-ores of Ashe County, N.C., 2G0. — C. H. Snow.
Copper Crystallization at the Copper Glance and Potosf Mine, New
Mexico, 308.— T. A. Rickard. The Gold Fields of Otago, 411.— T. A
Rickard.— Alluvial Mining in Otaso, 442.— W. H. Hoffmann. The late
Discovery of large quantities of Magnetic and Non-Magnetic Pyrite* in
the Croton Magnetic Iron-Mines, 613. — B. Willis. Studies in Structural
Geologv, 651.— J. Mali A Geological Map of the State of New York, 566.
— J. Sahlin. The Talc Industry of the G ouverneur District, St. Lawrence
County, New York, 683. — E. T. Durable. Note on the Occurrence of
Grahamite in Texas, 601 . — H. V. Winchell. The Mesabi Iron-Range, 644.
— T. A. Rickard. The Bendigo Gold Field, 686. — B. S. Lyman. An Occur-
rence of Coarse Conglomerate above the Mammoth Anthracite Bed, 713.—
H. B. Small. The Phosphate Mines of Canada, 774. — J. A. Church.
The Cause of Faulting, 782.— G. W. Garside. The Mineral Resource*
of South-east Alaska, 815. — W. S. Gresley. Note on Anthracite 'Coal
Apples ' from Pennsylvania, 824. — E. Wiltsee. Notes on the Geologv of
the Half-Moon, Pioche, Nevada, 867.— J. W. Powell. The Geological
Map of the United States, 877.— J. M. Hodge. The Big Stone Gap Coal-
Field, 922.— II. V. Winchell and J. T. Jones. The Biwabik Mine, 951.
—P. H. Griffin. The Manufacture of Charcoal-Iron from the Bog- and
Lake-Ores of Three Rivers District, Province of Quebec, Canada, 974.
Edinburgh. Edinburgh Geological Society. Transactions. Vol. vl
Part 5. 1893.
H. M. CadelL On Geological Chan pes wrot ight by Man within the
Forth Basin, 275. — H. M. Cadell. On the Old Lakes of Edinburgh, 1*7.
— J. Henderson. On Sections exposed on the Barnton Railway, 297.—
J. G. Goodchild. On the Minerals at Barnton, 301. — B. N. Peach and
J. Home. Notes on a Shell Mound, 303. — B. N. Peach and J. Home.
On the Occurrence of Shelly Boulder Clay in North Ronald shay, Orkney,
309. — H. J. Johnston-Lavis. On the Ejected Blocks of Monte Somtua,
314.
. Royal Scottish Geographical Society. Scottish Geographical
Magazine. Vol. ix. Nos. 7-12. 1893.
[Th. Thoroddsen.] The Wilds of Iceland, 411.— [— Hettner.] The
Andes of Western Colombia, 467. — H. Seebohm. Address to the Geo-
graphical Section of the British Association, Nottingham, 1893, 505.—
J. B. Don. Notes of a Journey in South Africa, 524.— C. It Markharn.
The Limits between Geology and Physical Geography, 633.
. . . Vol. x. Nos. 1-6. 1894.
J. Murray. Notes on an important geographical discovery in ^e
Antarctic Regions, 195. — V. Din^elstedt. A quiet corner of the Alp8»
242. — D. R. Urquhart. The Bolivian Altiplanicie, 302.
. Royal Society. Proceedings. Session 1892-93. Vol. xx-
(Pp. 1-160). 1893.
R. Munro. On a remarkable Glacier-Lake, formed bv a branch of
the Hardanger-Jokul, near Eidfiord, Norway, 53.— H. A Stocks. On
certain Concretions from the Lower Coal-Measures, and the Fossil Plsnts
which they contain, 69.
. . Transactions. Vol. xxxvii. Parts 1 & 2. 1893.
F. H. Hatch. The Lower Carboniferous Volcanic Rocks of Eft8*
Lothian (Garlton Hills), 115.— James Geikie. On the Glacial Succession
Digitized by
Vol.50.] ADDITIONS TO THB LIBRARY. 1 75
in Europe, 127. — M. Laurie. On some Eurypterid Remains from the
Upper Silurian Rocks of the Pentland Hills, 151. — J. Home and J. J. H.
Teall. On Borolanite — an Igneous Rock intrusive in the Cambrian Lime-
stone of Assynt, Sutherlandshire, and the Torridon Sandstone of Ross-
shire, 163. — R. Kidston. On the Fossil Plants of the Kilmarnock,
Galston, and Kilwinning Coal Fields, 307.
Ekaterinburg. Societe Ouralienne d'Amateurs des Sciences Natu-
relles. Bulletin. Tome xiii. Livr. 1. 1891-92.
Falmouth. Royal Cornwall Polytechnic Society. 60th Annual
Report, 1892. 1893.
. . 61st Annual Report, 1893. 1894.
F. J. Stephens. Notes on the Marazion and Perranuthnoe Mining
Districts, 113.
Frankfurt a. M. Senckcnbergische naturforschende Gesellschaft.
Abhandlungen. Band xviii. Heft 1. 1892.
. . . . Heft 2. 1894.
H. Engelhardt. Flora aus den unteren Paludinenschichten des Capla-
gTabens Dei Podvin in der Nahe von Brood (Slavonien), 169. — C. R.
Thost. Mikroskopische Studien an Gesteinen des Karabagh-Gaus (Ar-
menieches Hochland), 211.
. . Bericht, 1892-93. 1893.
Abhan d lutujen.
A. Andreae. Acrosawus Frischmanni, H. v. Mey. Ein dem Wasser-
leben an^epasster Rhynchocephale von Solenhofen, 21. — F. Schrodt. Die
Foramimferenfauna des miocanen Molassesandsteins von Michelsberg
unweit Hermannstadt (Siebenbiirgen), 155.
. . Katalog der Batracbier-Sammlung im Museum der,
von O. Boettgcr. (Svo.) 1892.
. . Katalog der Reptilien-Sammlung im Museum der,
I. Teil, von 0. Boettger. (8vo.) 1893.
Freiberg im Sachsen. Jahrbuch fiir das Berg- und Hiittenwesen
im Konigreiche Sachsen auf das Jahr 1893. 1894. Purcliased.
Freiburg i. B. Naturforschender Gesellschaft. Berichte. Band vi.
Hefte 1-4. 1891-92.
G. Boehm. Lithiotis problematica, Giimbel, 65. — W. Moericke. Ver-
gleichende Studien iiber Eruptivgesteine und Erzfuhrung in Chile und
Ungarn, 121. — G. Boehm. Ein Beitrag zur Kenntniss der Kreide in den
Venetianer Alpen, 134. — G. Steinmann. Bemerkungen iiber die tekto-
nische Beziehung der ober-rheinischen Tiefebene zu dem nordschweizer-
ischen Kettenjura, 150.
. . . Band vii. Hefte 1 & 2. 1893.
R. Herrmann. Das Kulmgebiet von Lenzkirch im Schwarzwald, 1.
— Fr. Pfaff. Untersuchungen iiber die geologischen Verhaltnisse zwischen
Kandern und Lbrrach im oadischen Oberlande, 117. — G. Bohm. Ccekts-
tarte und Het<>ro}>si*} 169.
. . . Band viii. 1894.
ADDITIONS TO TDTE LIBKART.
[Nov. 1894.
Geneva. Societe de Physique et d'Histoire Naturelle. Mcmoires.
Tome xxxi. Partie 2. 1892-93.
J. Brun. Diatomees, especes nouvelles marines, foasiles ou pelagiques,
No. 1.
Giessen. Oberhcssische Gesellschaft fiir Natur- und Heilkunde.
29" Bericht. lt>93.
F. Roth. Die Tuffe der Unigegend von Giessen, 41. — A. Streng.
Ueber die basaltischen Kraterbildungen nordlich und nordostlich tod
Giessen, 97. — A. Strong. Eine Reise in das Land der Mormonen, 112.
Gloucester. Cotteswold Naturalists' Field Club. Proceedings for
1892-93. VoLxi. Parti. 1893.
W. C. Lucy. Annual Address of the President, 1. — R. Etheridse.
On the Rivers of the Cotteswold Hills, within the Watershed of the
Thames, and their importance as supply to the Main River and the
Metropolis, 49.
. . for 1893-94. Vols. xi. Part 2. 1894.
Gotha. Pctcrmann's Mitteilungen. Band xxxix. 1893. Hefte
1-12. 1893. Purchased.
A. Supan. Ergebnisso der japanischen Erdbebenstatiitik, 16.— B.
Mierisch. Eine Reise nach den Goldgebieten im Osten von Nicaragua?
26. — F. Lowl. Die Tonalitkerne der Reiserferner in Tirol, 73, 113.—
A. Hettner. Die Anden des westlichen Eolumbiens, 129.-—C. Mitzo
pulos. Das grosse Erdbeben auf der Insel Zante im Jahre 1893, 166.—
E. von Rebeur-Raschwitz. Ueber die Aufzeichnung der Fernewirkungvn
von Erdbeben, 201. — A. Wichmann. Die Binnenseen von Celebes, 22o.
— W. Bodenbender. Die Pampa-Ebene im Osten der Sierra vou Cordoba
in Argeutinien, 231.— F. T. Koppen. Vorkommen des Bernsteins in
Rus^land, 249.
. . Band xl. 1894. Nos. 1-6. Purchased.
G. Schneiders. Die Sudostabteilung von Borneo, 27. — K. Hassert-
Die Landschaftsformen von Montenegro, 34. — F. ImmanueL Die Insel
Sachalin, 49.— J. Urafen Pfeil. Neu Mecklenburg, 73.— C. Sappor.
Kratertvpen inMexiko und Guatemala, 82. — J. Cornet. Die geologiscben
Ergebnisse der Katanga-Expedition, 121.— W. Moericke. 1st der Ceno
del Tupungata ein Vulkan ?, 142.
. . Erganzungs-Heft. No. 104. 1892. Purchased.
A. Hettner. Die Kordillere von Bogota, 1.
. . . No. 105. 1892. Purchased.
II. Mohn und F. Nansen. Wissenschaftliche Ergebnisse von Dr. r-
Nansens Durchquerung von Grbnland 1888, 1.
. . . No. 106. 1892. Purchased.
S. Ruge. Die Entwickelung der Kartographie von Amerika bis
1570, 1.
. . . No. 107. 1893. PurcJiased.
. . . No. 108. 1893. Purchased.
E. Naumann. Neue Beitrage zur Geologie und Geographie Japans 1-
. . . No. 109. 1893. Purchased.
G. Schott. Wissenschaftliche Ergebnisse einer Forschungsreise zur
See, ausgefiihrt in den Jahren 1891 und 1892, 1.
Digitized by Googl
Vol. 50.]
ADDITION'S TO THK LIBRARY
177
Gotha. Petermann's Mitteilungen. Erganzungs-Heft. No. 110.
1894.
Haarlem. Societe Hollandaise dee Sciences. Archives Ne'erlan-
daises. Tome xxvii. Livr. 1-6. 1893-94.
H. Behrens. Experiences sur la formation de fissures, de cavites et
noyaux pierreux dans les c6nes de debris. 149.
. . . Tome xxviii. Livr. 1. 1894.
Halifax (N. S.). Nova Scotian Institute of Science. Pro-
ceedings and Transactions. Series 2. Vol. i. Part 2. 1892.
H. S. McKay. Nova Scotia Gold Districts, xxxix. — T. C. Weston.
Notes on concretionary structure in various rock-formations in Canada.
137. — W. H. Prest. Evidence of the Post-glacial extension of the
southern coast of Nova Scotia, 143.— T. McCulloch. List of localities
for Trap minerals in Nova Scotia, 160. — E. Gilpin. The Geology of Cape
Breton, 167. — H. M. Ami. Catalogue of Silurian Fossils from Arisaig,
Nova Scotia, 185.
Halle. Naturforschende Gesellschaft. Abhandlungen. Band
xviii. Heftc2-4. 1894. Purchased.
F. Freeh. Die Karnischen Alpen, 161.
. . . Band xix. Hefte 1 & 2. 1893. Purchased.
Halle a.-d. Saale. Eaisorliche Leopoldinisch-Carolinische Dcutocho
Akademie der Naturforscher. Verhandlungen. (Nova Acta.)
Band lvii. 1892.
H. Engelhardt. Ueber die Flora der iiber den Braunkohlen befind-
lichen Tertiarschichten von Dux, 130. — H. Pohlig. Dentition und
Kranologie des Elephas antiquum, Falc, mit Beitragen iiber Elephas pri-
migenius, Blum., und Elephas tneridionalis, Nesti, 207.
. . . ( .) Bandlviii. 1893.
. . . ( .) Band lix. 1893.
. . . ( .) Bandlx. 1894.
. . Katalog der Bibliothek. lief. 4. (Band ii. Heft 1.)
1893.
Havre. Societe Ge'ologique de Normandie. Bulletin. Tome xiv.
1890. 1892.
G. Lennier. Note sur le Pterocera incerta de d'Orbigny,6. — G. Lionnet.
Note sur une Pierre a Polissoirs 4 La Koche au Diablo,' j>re9 de Nemours,
dont le moulage est depose" au Museum du Havre, 9. — E. Savalle. Coup
d'oeil sur Vdtat des falaises,de Cauville a Sainte-Adresse, 15. — E. Savalle.
La Sociele" Linneenne de Normandie au Havre,compte-rendu sommaire des
journe*es des 27, 28 et 29 Juin 1890, 18. — H. E. Sauvage. Description de
deux Especes nouvelles de Poissons du Terrain Kimmeridgien du Cap de
la Heve, 26.— G. Lennier. Etudes paleontologiques. Description des
Fossiles du Cap do la Heve, 31. — G. Lennier. Etudes sur un sondage
faite au Havre, rue Louis-Philippe, en 1887, 42. — E. Savalle. Le Havre
et ses environs aux temps pre'historiques, 61.
Digitized by Google
178 ADDITIONS TO THE LIBBAXY. [NOV. 1894.
Helsingfors. Geogranska Foreningen in Finland. Vetenskapliga
Meddelanden. I. 1892-93. 1893.
J. £. Rosberg. Nfigra sjobacken med deltabildninger i tinska Lapp-
marken, 1.— A. Tigerstedt. Om Finlanda malmforekoinster, 79.
. Suomen Maantietellinen Seura. (Societe de Geographic de
Finlande.) Fennia. Vol. viii. 1893.
J. J. Sederholm. Ueber den Rerggrund des sudlichen Finnlands,
No. 3, 1 and 165. — H. Berghell. Beobachtungen iiber den Baa und die
Configuration der Randmoranen im ostlicben Finnlande, No. 5, 1.
Hermannstadt. Siebenbiirgischer Verein fiir Naturwissenschaftexu
Verbandlungen und Mittheilungen. xlii. Jahrgang. 1S92.
Hertford. Hertfordshire Natural History Society and Field Club.
Transactions. Vol. vii. Parts 5-9. 1893-94.
J. Morison. Ice and its Work, 147.
Hobart. Royal Society of Tasmania. Papers and Proceedings
for 1892. 1893.
A. B. Biggs. Remarks on Sir Robert Ball's paper entitled "The
Astronomical Explanation of a Glacial Period," xvi, 21. — T. Stephens.
Specimen of an Orthoceratite belonging to the genus Actinocertu, from
the Silurian limestone at Railton, xvii.
Jena. Palaontologische Abbandlungen. Neue Folge. Band u
Heft 5. 1894. Purchased.
W. Dames. Ueber Zeuglodonten aus Aegynten und die Beziehungen
der Archaeoceten zu den iibrigen Cetaceen, 189.
. . . Bandii. Heft 3. 1894. Purchased.
Kotora Jimbo. Beitrage zur Kenntniss der Fauna der Kreideformation
von Hokkaido, 149.
Kiel. Naturwissenschaftlicher Verein fiir Schleswig-Holstein.
Schriften. Band ix. Heft 2. 1892.
. . Band x. Heft 1. 1893.
Kingston (Canada). Queen's College and University. Calendar
for the year 1894-95. 1894.
Konigsberg in Pr. Physikalisch-dkonomische Gesollschaf t. Schriften.
Jahrgang 33, 1892. 1892. Purchased.
Siizungsberichte.
Koken. Ueber Wirbeltierreste der samlandischen Bernsteinerde, 42.
Lansing, Mich. Michigan Mining School. Reports of the Director
for 1890-92. (8vo.) 1893.
La Plata. Museo de La Plata. Anales. Primera Parte. 1890-
1891. (Fol.)
Paleontologia Argentina. I. Catalogo de I09 Pajaros Fosiles
do la Republica Argentina, conservados en el Museo de La
Plata, por Francisco P. Moreno y Alcides Mercerat. 1891.
Digitized by Google
?o\. 50.]
ADDITIONS TO THE LIBRARY.
179
.a Plata. Museo de La Plata. An ales. Segunda Parte. 1S92.
Seccion Geologica y Mineralogica. I. Provincia de Mendoza.
Observaciones sobre el Mapa del departamento de Las Heras por
German Ave Lallemant. 1892.
. . . Tercera Parte. 1892 & 1893.
Paleontologi'a Argentina. II. Contribuciones al Conocimiento de
los Vertebrados Fosiles de la Argentina por R. Lydekker. 1893.
. . Re vista. Tomo i. 1890-91.
A. Mercerat. Notas sobre la Paleontologi'a de la Repiiblica Argentina.
!. Sinopsis de la familia de los Attrapotheridee, etc., 23/ ; II. Protoxodon-
ida • , etc., 379 ; III. Bunudontheridce, etc., 445.
. . . Tomoii. 1891.
A. Mercerat. Datos sobre restos de niamiferos fosiles, 5. — A.
Mercerat. Caracteres diagnosticos de algunas especies del ge"n. Theo-
todon, 47. — A. Mercerat. Caractdres diagnosticos de algunas especies
le Creodonta, 51. — F. P. Morenzo y A. Mercerat. Notas sobre algunas
?species de un genero aberrante de los Daswoda, 57. — F. P. Moreno.
Onohippidium Munizi, 65. — A. Mercerat. Formula dcntaria del gen.
Lietriotherium, 72. — A. Mercerat. Sobre la presencia de Restos de
Monos en el Eocene de Patagonia, 73. — A. Mercerat. Apuntes sobre
3I genero Typothtrium, 74. — A. Mercerat. Sobre un niaxilarde Creodonta,
SO. — A. Mercerat. Observacion relativa a Mephitis fossittis, 82. — A. Mer-
cerat. Sobre el maxilar inferior de un Perro, 82. — C. V. Burmeister.
Breves datos sobre una escursion a Patagonia, 275.
. . . Tomoiii. 1893.
R. Hauthal. La Sierra de la Ventana, 3. — T. Bridges. Datos sobre
Tierra del Fuego, 19, 313. — J. de Sieiniradgki. Apuntes sobre la Region .
Sud-Andina del Alto Limay v sus afluentes, 30-3. — F. P. Moreno, hoti-
cias sobre algunos cetaceos fosiles v actuales de la Repiiblica Argentina,
381.
. . . Tomoiv. 1893.
R. Hauthal. Informe sobre el Descubrimiento de Carbon de Piedra
de San Rafael (Provincia de Mendoza J, 101. — R. Hauthal. Nota
sobre un nuevo genero de Filiceos de la Formacion Rhetica del Challos
(Provincia de Mendoza), 221. — C. V. Burmeister. Nuevos datos sobre el
Territorio Patag<mico de Santa Cruz, 225, 337.
Lausanne. Societe Ge'ologiquo Suisse. Eclogse. Vol. iii. Nos. 4
& 5. 1893.
E. Favre et H. Schardt. Revue Gdologique Suisse pour l'annee 1892,
299.— F. Miihlberg. Exkursion von 1892 im Nord-Jura, 413.
. . . Vol. iv. Nos. 1-2. 1893-94.
L. Rollier. Etude stratigraphique sur les Terrains tertiaires du Jura
Bernois. (Partie septentrionale), 1. — II. Schardt. Coup d'ceil sur la struc-
ture geologique des environs de Montreaux, 29. — E. Renevier et M.
Lugeon. Excursion dans le Chablais, 50. — E. Renevier. G6ologie des
Prealpes de la Savoie, 53. — F. Lang. Jahresbericht iiber die geologische
Karte der Schweiz, 81. — II. Schardt. Sur Torigine des Prealpes Ro-
mandes (Zone du Chablais et du Stockhorn), 129. — E. Favre et H. Schardt.
Revue geologique pour 1893, 145.
l8o ADDITT058 TO THE LI BEAR Y. [NOV. 1894.
Lausanne. Societe Vaudoise des Sciences Naturelles. Bulletin.
Ser. 3*. Vol. xxix. Nos. Ill & 112. 1893.
H. Schardt. Coup d'ceil sur la structure geologique des environs <k
Monteraux, 241.
. . . . Vol. xxix. No. 113. 1893.
L. Gauthier. Premiere contribution a l'histoire naturelle des lacs de 1*
Valine de Joux, 294.
. . . . Vol. xxx. No. 114. 1894.
Lawrence, Kansas. The Kansas University Quarterly. VoL i.
No. 1. 1892.
S. W. Willieton. Kansas Pterodactyles, Part I., 1.— S. W. Williston
and E. 1). Cope. Kansas Mosasaurs, Part L, 14.
Leeds Philosophical and Literary Society. Annual Report for
1892-93. 1893.
Leicester. Leicester Literary and Philosophical Society. Transac-
tions. New Quarterly Series. Vol. iii. Parts 4-6. 1893-
94.
Montagu Browne. A Contribution to the History of the Geology of
the Borough of Leicester, 123. — J. D. Paul. St. John's Stone, 203.
Leiden. Geologisches Beichs-Mnseum. Sammlungen. NeueFolge.
(4to.) Bandi. Heft 1. 1891. Purchased.
K. Martin. Die Fossilien von Java, lstes Heft Die Foraminiferen-
fuhrenden Gesteine, 1.
Leipzig. Naturwissenschaftlicher Verein fur Sachsen und Tbiirin-
gen. Zeitschrift fur Naturwissenschaften. Band lxvi. Hefte
1-6. 1893-94.
. Zeitschrift fiir Krystallographie und Mineralogie. Band xxi.
Hefte 5 & 6. 1893.
H. Vater. Ueber den Einfluss der Losun*rs'ronossen auf die Krystal-
lisation des Calciuracarbonates, 433.— E. von Fedorow. Universal- (Theo-
dolith-) Methode in der Mineralogie und Petrographie, 574.
. . Band xxii. Hefte 1-6. 1893-94.
A. J. Moses. Ettringit und Alabandin von Tombstone, Arizona. 16.—
L. J. Igelstrom. Chondrostibian, ein neues Mineral von der Mangan-
erzgrube Sibgrufvan, Kirchspiel Grythyttan, Gouv. Oerebro, Schweaen,
43. — II. Rlieineck. Die chemitschen Grundfornieln des Turmalins, 52.—
F. Scherer. Arsenkies von Weiler im Ekass, 61.— A. C. Gill. Beitritfe
zur Kenntniss des Quarzes, 97.— G. A. F. Molengraaff. Ueber einig*
Erz- und Mineralvorkommen in der sudafrikanischen Kepublik Trans-
vaal, 150. — H. Vater. Ueber den Einfluss der Lbsunffsgenossen auf die
Krystallisation des Calciuuicarbonates, 209. — E. von Fedorow. Universal"
(Theodolith-) Methode in der Mineralogie und Petrographie, 229.— vt-**
Giimbel. Bei dem Bleihuttenprocess in Freyhung erzeugte MonticelJit-
artige Krystalle, 269.— J. W. lletaers. Ueber da9 Krvstallsystem des
Zinniodids, 270. — K. Oebbeke. Topas ira Fichtelffei)irge, ' 273.--H-
Ilheineck. Die chemische Natur des Axinit, 275. — II. Zimanyi. V®
Hauptbrechungsexponenten der wichtigeren gesteinsbildenden Minera-
lien bei Na-Licht, 321. -T. Gissinger. Ueber Caltitkrystalle von
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
l8l
Feldkirch, 359 .— T. Gissinger. Neue Fliichen am Euchroit, 367.— R.
Scharizer. Zur Frage der Structurformeln der metasomatischen Zersetz-
unirsproducte, 369. — H. A. Miers. Ueber Xanthokon uud Hittingerit,
nebst Bemerkungen iiber die Rothgiltigerze, 433. — G. A. Konig and
L. L. Hubbard. Ueber Powellit von einem neuen Fundorte, 463. — L. J.
Igelstrora. Neue Mineralien aus der Sjogrube, Gouv. Oerebro, Schweden,
467.— M. Pinere. Ueber Topazolith uud Melanit, 478.— W. E. Hidden.
Zwei neue Fundorte fiir Tiirkis, 582. — E. Weinschenk. Topazolith aus
dem Cipitbach, Seisser Alpe, 553.
Leipzig. Zeitechrift fiir KrystaUographie uud Mineralogie. Band
xxiii. Hefte 1 & 2. 1894.
W. Barlow. Ueber die geometrischen Eigenschaften homogener
starrer Structuren und ihre Anwendung auf Krystalle, L — S. L. Penlield
und J. II. Pratt. Ueber die chemische Zusanimensotzung des Stauroliths
und die regelmassige Anordnung der kohligen Einschliisse seiner Krvs-
talle, 64. — 8. L. Penlield. Beitrage zur KrvstaUisation des Willeimts,
73.— S. L. Penfield und W. T. H. Howe. Ueber die chemische Zusam-
mensetzung des Chondrodits, H umits, und Klinohuniits, 78. — E. von
Fedorow. Das Grundgesetz dor Krvstallographie, 99. — L. V. Pirsson.
Ueber die Krvstallform des Enargit, 114. — S. L. Penfield. Ueber die
KrystaJlforni des Herderit, 118. — V. Goldschniidt. Pbosgenit vou Mon-
teponi, 139.
. . Repertoriutn der Mineralogischen und Krystallo-
graphischen Literatur vom Anfang d. J. 1885 bis Anfang d. J.
1891 und Generalregister der Zeitechrift fiir Krystallographie
und Mineralogie. Bando xi.-xx. Von P. Groth und F.
Grunting. II. Theil. (Generalregister von F. Griinling.)
8vo. 1893. Purchased.
liege. Societe Geologique de Belgique. Annales. Tome xviii.
Livr. 1. 1891.
Bulk tin.
C. Malaise. Sur la position probable de quelques roches cristallines du
Brabant dans la sene stratigraphique, xvi. — M. Lohest. Sur la position
geologique des couches qui ont contribue" a la formation des depots de
phosphate de chaux do la Hesbaye, xix. — G. Cesaro. Etude des crista ux
de cinabre obtenus par M. L.-L. de Koninck pnr Taction de l'air sur une
solution do sulfure inercurique dans le sulfure sodique, xxviii. — G. Cesaro.
Observation sur la mdthode employee par M. de Koninck pour la repro-
duction du cinabre, xxix. — G. Cesaro. Idees sur le mode de formation de
la barytinede Rumelange, xxx. — G. Cesaro. Sur le modede formation de
la barytine, xxxviii. — G. Cesaro. Sur un mineral, provenant de Quenast,
qui est probablement de l'adulaire, xl. — V. Dormal. Observations au
aujet du compte-rendu de l'excursion de la SociCte" dans la vallee de
rOrneau en 1889, xlviii. — G. Dewalque. Deux fossiles nouveaux du
d^vonien de l'Orneau, lii. — X. Stainier. Ddcouverte du cinabre en Bel-
gique, Hi. — X. Stainier. Concretions ferrugineuses des psammites du
Condroz, lv. — G. Cesaro. Adulaire de Quenast, lvii. — G. Cesaro. La
prehnite de (Quenast, lviii. — G. Dewalque. Sur quelques fossiles dea
ardoises de Warmifontaine (Xeufchateau), lxi. — X. Staiuier. Les car-
rieres de calcaire devonien de Rhisnes, lxiii. — X. Stainier. Anthracite
et blende dans les calcaires devoniens de Rhisnes et de Bovesse, lxviii. —
H. Forir. Relation entre l'etage landenien beige et les couches inferieures
du svsteme eocene du bassin de Paris, d'apres MM. von Koeuen et Gosse-
ADDITIONS TO TIIF. LI BRAKY.
[Nov. 1S94,
let, lxxi. — G. Cesaro. Cristaux de Vanadinite presentant nettement le?
caracteres du groupe dihexaGdrique anormal, Ixxix. — G. Cesaro. Obser-
vations sur le prisme primitif des mineraux du groupe de l'apatdte, LrxxL
— G. Cesaro. La Hatchettine et l'Ozocente, Ixxxviii. — E. Delvaux.
Decouverte d'une molaire ftElephas antiqum et de restes d'espeoee
quaternaires dteintes dans les alluvions stratifies de la colline de Mesvin.
xc. — E. Delvaux. Sur un caillou erratique, originaire du Si. Gothard,
recueilli pres de Beverst, dans la valine du Demer, xcv.
Mhnoire*.
C. de la "Vallee Poussin. Notes sur les rapports des e'tage tournaisien
et viseen de M. E. Dupont avec son e*tage waulsortien, 3. — H. Forir.
Quelques particularitcs remarquables de la planchette de Herve. Roches
cr^tacees, argiles a silex, phospnate de chaux, sable et argile tertiaires, 15.
— X. Stainier. Etude sur Passise de Rouillon, 25. — X. Stainier. Li mite
de l'Ahrien et du Burnotien sur le littoral du Condroz, 43. — X. Stainier.
Le poudingue do Naninne a Strud et a Dave, 47. — X. Stainier. Les
failles de Samson, 53. — X. Stainier. Le terrain houiller a Salzinne-les-
Moulins, 59. — X. Stainier. Le gres blanc de Maizeroul, 6L — G. Cesaro.
Sur les notations compliquees des cristaux de calcite, 63. — E. Delvaux.
Sur un terme nouveau du quaternaire inferieur observe en Belgique, 75.
— E. Delvaux. Etude stratigraphique et paleontologique du sous-sol de
la Campine, 107. — E. Delvaux. Les puits art^siens du Hainaut occi-
dental, 105. — E. Delvaux. Les cailloux de silex roules coustituant la
base de l'^tage ypresien sous la ville de Renaix, 161. — M. Lohest. Sur
la signification oes conglomerats a noyaux schisteux des psamniites du
Condroz, 195. — C. de Stefani. Les terrains tertiaires superieurs du
bassin de la Me\literranee, 201.
Liege. Societe Gcologique de Belgique. Aunales. Tome xix.
Livr. 2. 1892.
Bulletin.
G. Schmitz. Le rfile de lTiumidite* dans l'«5tude et la recherche des
fossiles, 38. — A. Collon. Sur un cristal de Zircon, a1 gl bx a„, 39. — G.
Cesaro. Orientation de cristaux de quartz par un cristal de "calcite a
Chokier, 43. — M. Lohest. Sur les analogies de gisement du gaz nature!
aux Etats-Unis et du grisou en Belgique, 44. — AI. Lohest. Sur le recul
des chutes du Niagara, 51. — E. Delvaux. Un mot de reponse a la reven-
dication de priorite" de M. J. Ladriere, 62. — X. Stainier. Note sur les
terrains cr^taces et tertiaires de Vezin, 72. — G. Cesaro. Sur la forme
cristAlline de loxyde de zinc, 74. — G. Cesaro. Clivage octa£drique dans
une galene de Nil-St.-Vincent, 76. — G. Cesaro. Le mispickel de Laifour
(Ardennes), 76. — G. Fournier. Note proliminaire sur Texistence de la
faune de Waulsort dans les Stages viseen et tournaisien du calcaire
carbonifere, 77.
M&moires.
X. Stainier. Contribution a l\5tude du frasnien, 99. — C. de la Vallee
Poussin. Rapport sur le memoire precedent, 107. — G. Dewalque. Obser-
vations sur la correlation des diverses bandes consid^rees comme fras-
niennes par M. X. Stainier, 109.— II . de Dorlodot. Rapport sur le
memoire precedent, 119.— C. Mnlaise. Quelques observations relatives
au devonien du bassin de Namur, 131. — C. Gillet. De la formation des
depots de phosphate de chaux dans la province de Liege, 133. — M. Lohest
Sur une analogic de formation d'une varigte" de phosphate de chaux de
Hesbaye et des phosphates de Curacao et de la Floride, 143.— X. Stainier.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LI BRAKY.
183
Response aux observations presentees a l'occasion de mon travail sur le
frasnien, 147. — G. Dewalque. Re"plique a la re"ponse de M. Stainier,
155.— E. G. Detienne. Distribution d'eau de Bruxelles. Capitation par
drainage dans rEntre-Sambre-et-Meuse, 159.
Liege. Societe Gcologique de Belgique. Annales. Tome xx.
Livr. 1 & 2. 1893.
Bulletin.
X. Stainier. Presence du soufre dans le calcairo carbonifere de Spy,
xxiv. — X. Stainier. Aragonite de Lovegnee, xxv. — X. Stainier. Exten-
sion du Hervien jusque Onoz-Spy, xxv. — X. Stainier. Gal^ne dans le
irres taunusien de Ben-Ahin, xxvi. — II. de Dorlodot. D6couverte du
Waulsortien dans le baasin de Namur, xxxiii. — G. Dewalque. Sur les
cannelures des quartzites cambriens de Challes (Stavelot), hi. — C. de la
Vallee Poussin. Extension du givetien au sud de Rochefort, liv. — M.
Loheat. Rapport sur une note de M. Stainier relatif au houiller de Gives,
lxi. — G. Dewalque. Sur la presence pretendue de la houille dans l'Eifel,
lxii. — L. Bayet. Sur l'existence de schistes noire dans le coblencien de
l'Entre-Sanibre-et-Meuse, lxvii. — V. Dornial. Sur la presence des sables
dans l'Ardenne, lxix. — V. Dormal. Sur le puits artesien de Lasoye, lxxii.
— G. Dewalque. Sur le calcaire carbonifere de la carriere de Paire
(Clavier), lxxiii. — T. Rupert Jones et J. W. Kirkby. Sur une Leperditia
nouvelle, du calcaire carbonilere de la Belgique, lxxviii.— C. de la Vallee
Poussin. (Discours de M. le President), lxxxi. — P. Destinez. Sur quel-
ques fossilesdu houiller de Bois-Jk)reu, xciv. — G. Dewalque. Surquelques
fossiles carboniferes du niveau Yb a Sprimont, xcv. — H. de Dorlodot.
Quelques reflexions a propos de la faune de Paire (Clavier), xcvi. —
E. Nihoul. A propos de l'origine des phosphates de chaux de la Hesbaye,
cvi. — A. Peterniann. A propos de l'origine des phosphates. — H. Forir.
Sur le prolongement occidental du bassin de Tneux, ex. — V. Dormal.
Un nouveau gite de sable, stratifie, tertiaire, en Ardenne, cxi. — L. Bayet.
Le calcaire carbonifere de Beaumont, cxii.
M&moires.
X. Stainier. Decouverte du Receptaculites neptuni dans la bande de
Rhisnes, 8. — A. Firket. L'eau minerale et le captage de Harre, 7. —
X. Stainier. Materiaux pour la faune du houiller de Belgique, 43. —
J. Libert. Sur la temperature des roches et la nature des eaux des mines
de houille prolbndes, 59. — L. L. de Koninck. Sols alcalins dans les eaux
de charbonnages, 69. — E. Renault. La calcite de Landelies, 75. — G.
Cesaro. Sur deux propridtes geonnStriques du scale"no<klre dl dans la
calcite, 81. — G. Cesaro. Determination du signe optique des lames cris-
tallines, 87. — A. Firket. Sur quelques roches combustibles beiges,
assimileesou assimilables au 'Cannel coal1 anglais, 107.— II. Forir. Sur la
bande devonienne de la Vesdre, 111. — M. Mourlon. Sur le gisement de la
Rhynchonella? Gosseleti, Mourlon, decrite par M. D. G^hlert, 119. —
D.-P. (Ehlert. Description de la Khynchonella? Qosseleti, Mourlon, 125.
— X. Stainier. Le terrain houiller de Bouge et de Lives, 133. — A.
Foniakof. Etude geologique des gites auriferes de la Siberie, 141.
Bibliographic
X. Stainier. Bibliographie gonerale des gisements de phosphates de
chaux, 3.
. . . Tome xxi. Livr. 1 & 2. 1893-94. 1894.
Bulletin.
M . Lohest. Sur 1 age du calcaire de Lens et de la dolomie de Cambron,
VOL. L. p
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
xxiv. — C. Malaise. Sur des fragments de rhyolithe de Monstreux, xxviii.
— H. de Dorlodot. Cartes geologiques de la planch ette de Din ant, xxxi.
— X. Stainier. Sur la bande deVonienne de la Vesdre, xxxvii.— M. Lohest
Sur un ravinement contemporain de la sedimentation dans les psammites
du Condroz de Villers-le-Temple, xzxix. — V. Dormal. Quelaues mots
sur le calcaire carbonifere dans la vallee de la Me"haigne, xlv. — V. Dormal
Sur la limite entre le coblencien et le gedinnien longeant le massif cambrien
de Givonne, xlviii. — V. Dormal. Le mineral de fer des plateaux de
PArdenne, lii. — J. Dupont. Note sur des ossements humains trouv£s dans
les mines du Djebel Sidi Ahmed, lvi. — M. Lohest. Sur les cailloux roules
de quartzite recontres au mur de la coucho Grande Moisa du charbonnage
de La Haye, a Liege, lviii. — P. Tabary. Magnetite (aimant) dans la
limonite de Mont-St.-Martin, lxi. — G. Schmitz. A propos des cailloux
roules du houiller, lxxi. — V. Dormal. Re'ponse a M. de Dorlodot a propoa
de ses observations sur ma note intitule*e u Sur la limite entre le Coblen-
cien et le Gedinnien longeant le massif cambrien de Givonne, lxxv. —
M. Lohest. — Sur les blocs landeniens d'Ellemelle, lxxviii, lxxxv. —
G. Dewalque. — Un nouveau giseroent de fossiles siluriena a Ombre t,
lxxx. — G. Cesaro. La dolomie de Prayon, lxxxix. — M. Lohest. Sur un
echantillon de halite decouvert au charbonnage de La Haye, a Liege,
xciii. — M. Lohest. De"couverte de fossiles dans le Rhenan du bord nurd
du bassin meridional, xciv. — C. Malaise. Sur la decouverte de Beyrichia
dans le Silurien beige, xcv. — H. de Dorlodot et C. Malaise. Nouvelles
observations relatives a la discordance du poudingue d'Onibret sur le
Silurien, xcvi.
II. de Dorlodot. Sur le niveau stratigraphique des Cardiola retrostriata
de Olaminforge, 3. — H. de Dorlodot. Note sur Topportunit^ des le*gendes
speciales, 13. — H. de Dorlodot. Un dernier mot sur la coupe de Pierre-
P6tru, 23. — A. Briart. Geologie des environs de Fontaine-PEveqae et
de Landelies, 35. — G. Cesaro. Sur la matiere colorante des psammites
rouges du Condroz, 105. — G. Cesaro. Barytine et Aragonite en end nits
cristallins sur des schistes au contact des psammites du Condroz, 111. —
G. Cesaro. Le Mica des psammites du Condroz, 117.— A. Briart
£tude sur la structure du Bassin Houiller du Hainault, 125.
Lille. Societe Geologique du Nord. Annales. Tome xxi. 1893.
Livr. 2-4. 1893-94.
H. Parent. Notes suppl^mentaires sur les Plis du Nord de PArtois,
93. — H. Parent. Les Gres primaires de PArtois, 104. — C. Barrois. Sur
le Rouvilloqraptus Richardsoni de Cabrieres, 107. — J. Gosselet. Compte-
rendu de PExcursion a Audruick et a Pont d'Ardes, le 23 Avril, 1?*98,
114. — J. Gosselet. Compte-rendu de PExcursion geologique aFre*vent et
a Buire, le 30 Avril, 1893, 116.— »-J. Gosselet Geographic physique du
Nord de la France et de la Belgique: La Plaine maritime, 119. —
J. Gosselet et J. Ladriere. Note sur la coupe du canal d'Audruick et sur
le tuf calcaire de Saint-Pierre, 139— H. Spe"tebroot. Excursion geolo-
gique a Aire, 146. — J. Gosselet. Gites de Phosphate de Chaux aux
environs de Fresnoz-le-Grand, 149. — C. Helson. Note sur les Pyrenees
Orientales, 159. — J. Gosselet L'Argile a Silex a Werchain, 173. —
J. Gosselet. Cours de Geographic physique, 176. — C. Duron. Excursion
au Caillou-qui-Bique, 197. — Ii. Parent. Sur Pexistence du Gault entre
les Ardennes et le Bas-Boulonnais, 206. — C. Helson. Sur le gisement
de Phosphate de Chaux dans le Tarn-et-Garonne et le Tarn, 246. —
H. Parent. Sur une nouvelle espece d'Ammonite du Gault, 265. —
V. Vaillant. Esquisse pre*liminaire sur les Phosphates de la Floride,
271.— C. Maurice. Compte-rendu sur PExcursion du 22 Octobre, 1893,
Digitized by Google
ol. 50.]
ADDITIONS TO THE LIBRARY.
185
Mons-en-Pevele, 328. — G. F. Dollfus. Considerations sur la limite
ud du Bassin Houiller du Nord de la France, 332. — Rabelle. Quelques
bservations geologiques faites aux environs de Ribemont, rive gauche
3 rOise, 344. — J. Gosselet. Lecon d'ouverture du Cours de G6ologie
rofessi a la Faculte des Sciences de Lille, le 25 Novembre, 1893, 349. —
ivien. Sur l'eau de la source du Grosnard alimentant la ville de
t. Quentin, 371. — C. Barrois. Legende de la Feuille de Plouguerneau
Ouessant, 382.
ille. Societe Ge'ologique du Nord. Annales. Tome xxii. 1894.
Livr. 1. 1894.
H. Parent Notes sur les terrains tertiaires du Pays de Caux, L —
Tisser. Note sur la de*couverte, par M. Veillerot.de Silex mouateViens
la Goulaine (Saone-et- Loire), 10. — J. Roussel. Etude strati graphique
a Pyrenees, 18. — C. Barrois. L£gende de la Feuille de Rennes, 21. —
Gosselet. Cours de Geographic physique du Nord de la France et de
Belgique, 38. — C. Jannel. Alluvions des plateaux et essai sur la
nese des valines, 50.
shon. Socicdade de Geographia. Boletim. Serie 12a. Nos. 1-
12. 1892 ft 1893.
C. J. Alford. De Durban a Beira, 105.
— . . . Serie 13. Nos. 1 & 2. 1894.
verpool. Geological Society. Proceedings. Session 1892-93.
Vol. vii. Part 1. 1893.
\V. Hewitt. The Phvsical Conditions of the Aralo-Caspian Region,
bearing on the Conditions under which the Triassic Rocks were formed,
.— T. Mellard Reade. The Drift-beds of the Moel Tryfaen area of the
>rth Wales Coast, 36. — J. Lomas and A. R. Dwerryhouse. The Glacial
•posits on the Shore of the Mersey, between Hale Head and Decoy
irsh, 80. — L. dimming. Some Observations on Mountain Debris, 87.
U. Ricketts. On some Conditions existing during the Formation of
1 Older Carboniferous Rocks, 94. — E. Dickson. Note on Section at
illaw Clough, near Parbold, 100. — P. Holland and E. Dickson,
marks on the Formation of Clay, 108. — J. Lomas and A. R. Dwerry-
use. On some Faults in Arno Quarry, 118.
ndon. Annals and Magazine of Natural History. Series 6.
Vol. xii. Nos. 67-72. 1893. Purchased.
I. G. Seeley. On a Reptilian Tooth with two Roots, 227, 274.—
Smith Woodward. Further Notes on Fossil Fishes from the Karoo
nuation of South Africa, 393. — A. Smith Woodward. On some
tish Upper-Jurassic Fish-Remains of the Genera Caturus, Gyrodus,
I Notidanus, 398.
— . . . Vol. xiii. Nos. 73-78. 1894. Purchased.
>. Da vies Sherborn. On the Dates of Sowerbv's ' Genera of Recent
I Fossil Shells,' 370.— H. G. Seeley. Research es on the Structure
ranization, and Classification of the Fossil Reptilia, 374, 451, 452. —
L). Dana. Observations on the Derivation and Homologies of some
;iculates, 502. — A. Smith Woodward. On the Affinities of the
taceous Fish Proto*phyrcenay 510.
-. Annals of British Geology, 1892. By J. F. Blake. 8vo.
1893. Purchased.
p2
ADDITIONS TO TEE LIBRARY.
[Nov. 1894,
London. Athenaeum. (Journal.) Parts 787 -792. 1893.
. . ( .) Parts 793-798. 1894.
. British Association for the Advancement of Science. Report
of the Sixty-third Meeting, held at Nottingham in September
1893. 1894.
John Milne. Investigation of the Earthquake and Volcanic Phenomena
of Japan : Thirteenth Report of the Committee, 214. — C. Davison.
Report of the Committee on Earth Tremors, 287— C. E. De Ranee,
Nineteenth Report of the Committee on the Circulation of Underground
Waters, 463. — T. Rupert Jones. Tenth Report of the Committee on
Fossil Phyllopoda of tne Palaeozoic Rocks, 4(55. — Malcolm Laurie. The
Eurypterid-bearing Deposits of the Pentland Hills, 470.— 11. J. Johnstor*-
Lavis. The Volcanic Phenomena of Vesuvius and its Neighbourhood,
471. — 0. W. Jetfs. Fourth Report of the Committee on the Collection,
Preservation, and Systematic Registration of Photographs of Geological
Interest in the United Kingdom, 473. — A. Smith Woodward. The Regis-
tration of the Type Specimens of British Fossils, 482. — Dugald Bell. The
Character of the High-level Shell-bearing Deposits at Clava, ChapelhalL
and other Localities, 483. — P. F. Kendall Twenty-first Report of the
Committee on Erratic Blocks of England, Wales, and Ireland, 514. —
F. Clowes. On a Nottingham Sandstone containing Barium Sulphate
as a Cementing Material, 732. — J. J. H. Teall. Address to Section C :
Geology, 733. — E. Hull. Notes on the Water-bearing Capacity of the
New Ked Sandstone of Nottingham, 743. — E. Hull On tne Ijiscovery
of a Concealed Ridge of pre-Carboniferous Rocks under the Trias of
Netherseal, Leicestershire, 745. — J. L. Myres. On the Geology of the
Coastland of Caria, 746. — R. H. Traquair. On the Discovery of Ccpha-
Itutpis in the Caithness Flags, 747. — Montague Browne. On some Verte-
brate Remains not hitherto recorded from the Rhtetic Beds of Britain,
748.— G. Fowler. Note on a Fault at Cinder Hill, 749. — H. Hicks.
On the Base of the Cambrian in Wales, 750. — E. T. Newton. On the
Keptilia of the British Trias, 752. — J. P. Iddings. The Dissected Volcano
of CrandaU Basin, Wyoming, 753. — Sir Archibald Geikie. On Structures
in Eruptive Bosses which resemble those of Ancient Gneisses, 754. —
W. J. Sollas. On the Pittings in Pebbles from the Trias, 755.— V. Ball.
On Bones and Antlers of Cervtu giganteus incised and marked by Mutual
Attrition while buried in Bogs or Marl, 756. — R. D. Oldham. * Note to
accompany the Exhibition of a Geological Map of India, 756.— H. J.
Johnston-Lavis. On Quartz Enclosures in Lavas of Stromboli and
Strombolicchio, and their Effect on the Composition of the Rock, 759. —
A. T. Metcalfe. On the Gypsum Deposits of Nottinghamshire and
Derbyshire, 760.— H. B. Woodward. On a Bed of Oolitic Iron-ore in
the Lias of Raasay, 760. — A. C. G. Cameron. Note on a Transported
Mass of Chalk in the Boulder Clay at Catworth in Huntingdonshire, 760.
— J. G. Goodchild. Augen Structure in Relation to the Origin of Eruptive
Rocks and Gneiss, 761. — W. C. Brogger. The Genetic Relations of the
Basic Eruptive Rocks of Gran (Kristiania Rerion), 762.— J. P. Iddings.
Petrological Features of the Dissected Volcano of Crandall Basin,
Wyoming, 763. — A. Harker. Berthelot's Principle applied to Magmatic
Concentration, 765. — W. J. Sollas. On the Origin of Intermediate
Varieties of Igneous Rocks by Intrusion and Admixture, as observed at
Barnavave, Carlingford, 765. — W. J. Sollas. On the Transformation of
an Amphibolite into Quarta-mica-diorite, 765. — F. T. Howard and E. W.
Small. On some Igneous Rocks of South Pembrokeshire, with a Note
on the Rocks of the Isle of Grassholme, 766. — W. W. Watts. Notes on
Digitized by Google
(37. — A. 1
dan and '
Occurrei
ingrham,
n, 769.-
Triansie
luscan R«
Obsen
770.— fl
3. A. J.
On Geol<
i Glaciat
lacial Ge
in and E
bott and
-W. J. :
fell. On
78.— C.
jancashii
initio Bo
the Dert
uaxtz Gri
of the Sk
gs of A)
ions of G i
t of So
rchased.
iisive.
1893.
TO.— The
ie Iron Dc
.merican
6, 499, i
[oselle, F
with Abn
urgh Cot
orthumtx
is. Geol
atterson.
a, 1023.
Ida of F
>3.— The
eld, 304.
-The Cu
ler. Th<
irginia, A
Digitized by Google
jgg ADDITIONS TO THE LIBBAUT. [NOV. 1S9+.
The Forest of Wyre Coalfield, 497.— G. E. J. McMurtrie. The Yorkshire
Coalfield, 510.— The Lancashire Coalfield, 640, 689, 761, 785, 848. —
C E Willis The Asbestos Fields of Port au Port, Newfoundland. 641.
—The Rhenish-Westphalian Coalfield, 688, 736, 880, 929, 975. — F. L.
Nason. The Franklinite Deposits of Mine Hill, Sussex County, New
Jersey 706. A. Firket. Some Belgian combustible Bocks assimilated
or assimilable to Cannel Coal, 848.— J. G. Summons. The Pembroke-
shire Coalfield, 941.— The Coal Deposits of Siberia, 943. — J. C. I'Anson.
Oalifornian Coal, 1041.— Coal Measures of Alabama, 1072. — F. Laur.
The Bauxites : A Study of a New Mineralogical Family, 1090— The
Shropshire Coalfield, 1119— J. Randall. The {Shropshire Coalfields and
their Surroundings, 1071.— A. Firket. The Origin and the Mode of tho
Formation of Coal, 1181.— Deahayes. Sosnowice Collieries, Dombrova
Coalfield, Russian Poland, 1214.
London. East India Association. Journal. Vol. xxt. Nos. 7 & 8-
1893.
. . . Vol. xxvi. Nos. 1-4. 1893-94.
4 Geological Magazine. Decade 3. Vol. x. Nos. 6-12.
1893.
V. Ball. The Volcanoes of Barren Island and Narcondam in the Bay
of Bengal) 289.— C. Davison. On the British Earthquakes of 1892, 291.
—Sir Henry H. Howorth. The Condition of the Glacial Lands in the
so-called Glacial Age, 302— P. Lake. The Growth of the Indian
Peninsula, 309. — A. J. Jukes Browne. The Relative Age of Flints, 316.
Agnes Crane. New Classifications of the Brachiopoda, 318. — AY . Shone,
The Cause of the Crateriform Sand Dunes and Cwms, 323.— G. A. J. Cole.
The Rocks of the Volcano of Rhobell Fawr, 337.— F. Chapman and
C. Davies Sherborn. On the Ostracoda of the Gault at Folkestone, 346.
—Marshall Hall. Glacier Observation, more especially Colonial, 349.—
Sir Henry II. Howorth. The True Horizon of the Mammoth, etc., 353.—
C. Davison. Note on the Quetta Earthquake of December 20tb, 1892,
356 T. Rupert Jones. On some Fossil Ostracoda from S.VV. Wyoming,
and' from Utah, U.S.A., 385— C. Earle. The Evolution of the American
Tapir, 391.— H. Hicks. The pre-Cambrian Rocks of Wales, 396. — K. A.
von Zittel. The Geological Development, Descent, and Distribution of
the Mammalia, 401, 456, 501.— A. Smith Woodward. Some Cretaceous
Pycnodont Fishes, 433, 487.— Catherine A. Raisin. Contributions to the
Geology of Africa, 436. — E. W. Claypole. The Upper Devonian Fishes
of Ohio, 443.— C. S. Du Riche Preller. On the Origin of the Engadine
Lakes, 448. C. Davison. Note on the Growth of the Lake of Geneva,
454. — O. C. Marsh. Restoration of Coryphodon, 481. — H. B. Woodward.
On a Bed of Oolitic Iron-ore in the Lias of Raasay, 493.— Sir Henry H.
Howorth. The Recent Geological History of the Arctic Lands, 495.—
Wheelton Hind. Note on Myalina crassa (Fleming), 614— T. Rupert
Jones and Henry Woodward. The Fossil Phyllopoda of the Palaeozoic
Rocks, 528.— C. Callaway. On the Conversion ot Chlorite into Biotite
in Rock-metamorphism, 535— P. B. Brodie. Notes on the Eocene
Tertiary Insects of the Isle of Wight, 538.— Wheelton Ilind. Descrip-
tion of a Slab from the Shale above the Kinder Scout Grit, Rabchester.
Lancashire, 540.— A. J. Jukes Browne. The amount of disseminated
Silica in Chalk considered in Relation to Flints, 541.— A. Harker. Ber-
thelot's Principle applied to Magnetic Concentration, 546.
. . . Purchased.
Digitized by Google
Vol. 50.]
ADDITION8 TO THE LIBRARY.
London. Geological Magazine. Decade 4. Vol. i. Nos. 1-G.
1894.
Maria M. Ogilvie. Coral in the ' Dolomites ' of South Tyrol, 1, 49. —
A. H. Foord and G. C. Crick. On the Identity of EUipsolites compresm*,
J. Sowerby, with Ammonites Henslowi, J. Sowerby, 11. — C. W. Andrews
Note on a new Species of ALpyomis (AZ. titan), 18. — J. G. Goodchild.
Augen-structure in Relation to the Origin of the Eruptive Rocks and
Gneiss, 20. — C. S. Du Riche Preller. On the Three Glaciations in
Switzerland, 27. — W. M. Hutchings. Notes on the Composition of Clays,
Slates, etc., and on some Points in their Contact-metamorphism, 36, 04.
— J. W. Gregory. On some Jurassic Species of Cheilostomata, 61. —
A. Smith Woodward. On a Tooth of Oxyrhina, from the Red Crag, 75.
— T. Mellard Reade. An Ancient Glacial Shore, 76.— W. Shone. Post-
Glacial Man in Britain, 78. — Mark Stirrup. The True Horizon of the
Mammoth, 80. — A. R. Hunt. Four Theories of the Age and Origin of
the Dartmoor Granites, 97. — S. H. Reynolds. Fossils from the Lower
Palroozoic Rocks of Yorkshire, 108. — C. A. McMahon. The Rape of the
Chlorites, 111. — T. G. Bonney. Some Notes on Gneiss, 114. — J. E. Marr.
Notes on the Skiddaw Slates, 122. — A. Brown. On the Structures and
Affinities of the Genus Solenopora, 145, 195. — F. M. StapfF. On the
Sand-grains in Micaceous Gneiss from the St. Gothard Tunnel, and on
some other Difficulties raised by Prof. Bonney, 152. — Sir Henry H.
Howorth. The Mammoth Age was Contemporary with the Age of
Great Glaciers, 161. — P. B. Brodie. Further Remarks on the Tertiary
(Eocene) Insects from the Isle of Wight, and on others from the Lias and
Coal-Measures, 167. — A. Harker. Cordierite in the Lake District, 1(59.
— S. S. Buckman. Jurassic Ammonites : Notes on a Pamphlet by Dr.
Emile Haug, 170. — O. C. Marsh. Restoration of Camviosaurus, 193. —
T. Mellard Reade. On the Results of Unsymmetrical Cooling and Re-
distribution of Temperature in a Shrinking Globe as applied to the Origin
of Mountain Ranges, 203. — A. Smith Woodward. On a Second British
Species of the Jurassic Fish Eurycormtu, 214. — C. Callaway. On Chlorite
as a Source of Biotite, 217.— -G. A. J. Cole. On Variolite and other
Tachylytes at Dun more Head, Co. Down, 220. — J. Lomas. An Ancient
Glacial Shore, 222. — J. K. Creighton. On the Occurrence of Pigotite in
the Caves near Porthcurnow, St. Levan, Cornwall, 223. — F. R. C. Reed.
Woodwardian Notes (Phacojts Marri), 241. — C. D. Walcott. Note on
some Appendages of the Tnlobites, 246. — H. J. Johnston-Lavis. The
Basic Eruptive Rocks of Gran (Norwav) and their Interpretation, 252. —
K. EL Traquair. On a New Species of Diplacanthus, with Remarks on
the Acanthodian Shoulder-girdle, 254.— Sir Henry H. Howorth. The
most recent changes of Level and their Teachings. Part I. The Raised
Beaches, 257.
. . . PurcJutsed.
. Geologists' Association. Proceedings. Supplement to Vol. i.,
containing Papers published separately between the years 1859
and 1870. 1870.
. . . Vol. xiii. Parts 3-7. 1893-94.
S. Boulger. Report on the Visit to the British Museum (Natural
,>artment of Botany, 50. — F. C. J. Spurrell. Excursion to
-H. B. Woodward, C. Reid, and J. F. Blake. Excursion to
Bure Vallev, Cromer, and Lowestoft, 54. — F. C. J. Spurrell.
u to Dartford Heath, 70.— J. F. Blake. Excursion to Brill, 71.
. Monckton and H. A. Mangles. Excursion to Famham, 74. —
190
ADDITIONS TO THE LIBRARY.
[Nov. 1S94,
W. J. Lewis Abbott. A new Reading of the Highgate Archway Section,
84. — VV. J. Sollas. The Geology of Dublin and its Neighbourhood, QL.
— W. Topley. Excursion to Amwell and Chadwell Springs, 123. — H. B.
Woodward, IL H. VVinwood, W. H. Wickes,andE. Wilson. Excursion
to Bath, Midford, and Dundry Ilill, in Somerset, and to Bradford-on-
Avon and Westbury, in Wiltsnire, 125. — F. G. H. Price and T. Leighton.
Excursion to Hytne, Sandgate, and Folkestone, 143» — T. V. Holmes-
Excursion along the New Railway from Blackheath to Bexley Heath,
15JL — W. J. Lewis Abbott. Excursion to Basted and Ightham, 157. —
T. Leighton. Excursion to Abinger, 103. — G. A.J. Cole. Excursion to
the Counties of Dublin and Wicklow, 168. — T. V. Holmes. Excursion
to the Deneholes of Hangman's Wood, near Grays Thurrock, Essex, ITS.
— T. Leighton. On a Discovery of Fossils on a New Horizon in the
Lower Green sand at Little Stairs Point, Sandown Bay, Isle of Wight,
li^L=A. Smith Woodward. Notes on the Sharks' Teeth from British
Cretaceous Formations, 190. — H. W. Monckton. On a Specimen of
Eryma eUgana from the. Inferior Oolite of Dundry Hill, 21iL — W. F.
Hume. On the Genesis of Chalk, 911— H. B. Woodward. Geology in
the Field and in the Study, 24L
London. Glacialists' Association. See London. Glacialists' Magazine.
. Glacialists' Magazine. Vol. L No. 1-10. 1893-94.
Purchased.
C. E. De Ranee. Presidential Address to the Glacialists' Association,
1893,2. — A. R. Dwerryhouse. On an Intrusive Mass of Boulder Clay,
SL — K. Grossmann. Observations on the Glaciation of Iceland, £L —
Dugald Bell. The Granite Boulders of the Clyde Valley, 45.— E. HulL
The Great Submergence, QL — J. Lomas. On a Glacier Mill at Arno
Quarry, Birkenhead, (ML — P. F. Kendall. On a Moraine-like Mound
near Snowdon, 68* — W. Upham. American Notes, 73, 100. 121, 1
lZiL — G.H.Morton. Intrusive Boulder Clay, ZL=K. Grossmann. The
Crater Hverljall, 85. — H. W. Feilden. Mild Arctic Climates, 91. — A. C.
G. Cameron. Notes on a Transported Mass of Chalk in the Boulder
Clay at Catworth, in Huntingdonshire, 26. — P. F. Kendall. Supposed
Erratics on the Cotteswolds, 9_L — Elizabeth Dale. On the Glaciation of
the Country round Buxton, HL — C. E. De Ranee. On the Glacial Sands
and Gravels at Heck Station, Yorkshire, 13L — J. Lomas. The Great
Submergence, 134, 185. — F. Barke. Sections in the Drift at Shelton,
Hanley, lM^=N7lL Winchell. Pebbles of Clay in Stratified Gravel and
Sand, 171.- E. Dubois. The Cause of the Ice Age, 175, 21Z— H. Hicks.
The Evidence of Ice-action in North-west Pembrokeshire, 191. — Warren
Upham. The Epeirogenic Theory of the Ice Age, 21L
. Institution of Civil Engineers. Minutes of Proceedinsrs.
Vol. cxii. 1893.
. . . Vol. cxiii. 1893.
G. E. Cruttwell. The Foundations of the River-Piers of the Tower
Bridge, 117.
. . . Vol. cxiv. 1893.
M. B. Jamieson and James Howell. Mining and Ore-treatment at
Broken Hill, N.S.W., 11&
. . . Brief Subject-Index. Vols, lix.-cxiv. Sessions
1879-80 to 1892-93. 1893.
— . . Vol. cxv. 1894.
C. R. Parkes. Surface Tin-Mining in the Malay Archipelago, 352.
Vol. 50.] ADDITIONS TO THE LIBRARY.
London. Iron and Steel Institute. Transactions. Sessi
VoL i. Nos. 1, 3, 5, & 6. 1869.
1870. Vol.ii. No. 7. IK
Journal. 1879. Nos. 1 & 2. 1879.
. 1881. Nos. 1 & 2. 1881.
. 1883. No. 2. 1883.
. 1884. No. 1&2. 1884.
. 1892. Nos. 1 & 2. 1892.
. 1893. No. 1. 1893.
. 1893. No. 2. 1894.
Special Volume of " Proceedings." The
Steel Institute in America in 1890.
Section V. The Iron Ores of the United States, 6a— Section
the Geological Distribution of the Iron Ores of America ai
United Kingdom, 91.— Section VIII. On the Fuel of the Unit
128.— Section X. Limestone, 160.
Subject-matter Index to Proceedings, 18(
,1882-1889. 1891.
Catalogue of the Library, 1884.
Notes on Northern Industries by J. S. Jear
1883.
1876?
Linnean Society. Journal. Vol. xxvi. Botany.
1894.
. Vol. xxx. Botany. Nos. i
1893-94.
-. . . Vol. xxiv. Zoology. Nos. 155 & 15
-. . Proceedings. From November 1890 to Ju
1893.
-. . . From November 1892 to June 1893
-. . Transactions. Series 2. Botany. Vol. iii.
1893.
*
-. . . Series 2. Zoology. Vol. v. Par
1892-93.
-. London, Edinburgh, and Dublin Philosophical Maga
Journal of Science. Scries 5. Vol. xxxvi. Nos. i
1893. Presented by Dr. W. Francis, F.QJ3.
-. . Vol. xxxvii. Nos. 224-229. 1894. Pr&
Dr. W. Francis, F.G.S.
Digitized by Google
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
London. Mineralogical Society. Mineralogical Magazine. VoL x.
Nos. 47. 1893.
H. A. Miers and G. T. Prior. Xanthoconite and Rittincerite, with
remarks on tho Red Silvers, 185. — G. H. F. Ulrich. On a discovery of
' Oriental Ruby ' and * Margarite ' in the Province of Wcstland, 5>ew
Zealand, 217. — C. O. Trechmann. Binnite fromlnifeld in the Binnen-
thal, 220.— C. A. McMahon. Kotos on the optical characters of the
Globules and Spherulites of Lithium Phosphate and some other salts,
229. — G. T. Prior. Fersrusonit© from Ceylon, 234. — A. Marker. Extinc-
tion-angles in Cleavage-Flakes, 239. — II. Louis. On the mode of occur-
rence of Gold, 241. — M. F. Heddle. On the " Skin " of Agates, 248.
. Natural Science. Vol. iii. Nos. 17-22. 1893. Pverchated.
H. O. Forbes. Antarctica: a supposed former Southern Continent,
54.— A. Irving. On the work of Glaciers, 58. — F. E. Beddard. Earth-
worms and the Earth's History, 111. — A. Smith Woodward. Supposed
Fossil Lampreys, 128. — S. Bucknian. The Recapitulation Theory in
Biology, 138. — H. J. Johnston-La vis. Notes on the Pipernoid Structure
of Igneous Rocks, 218.— G. W. Bulman. The Effect of the Glacial
Period on the Fauna and Flora of the British Isles, 201.— -The British
Association Addresses, 1893, 293. — G. A. J. Cole. Geology in Secondary
Education, 332. — Clement Reid. Desert or Steppe Conditions in Britain,
867. — T. Mellard Reade. The Genesis of Mountain ltanges, 371. — T.
Mellard Reade. High-level Shelly-Sands and Gravels, 423. — A. Smith
Woodward. Note on the Evolution of the Scales of Fishes, 44S. —
Recent Explorations of the Maltese and Sicilian Caverns, 455.
. . Vol. iv. Nos. 23-28. 1894. Purchased.
R. Lydekker. The La Plata Museum, 27, 117. — J. Hornell. The
Influence of Volcanic Dykes upon Littoral Life and Scenery, 112. —
H. J. Johnston-Lavis. The Causes of Variation in the Composition o
Igneous Rocks, 134. — Sir J. W. Dawson. The Fossil Plants of Canada as
Tests of Climate and Age, 177. — G. Barrow. Thermo-metamorphism
in the South-eastern Highlands of Scotland, 198.— W. J. L. Aobott.
Plateau Man in Kent, 257. — T. M. Reade. Continental Growth and
Geological Periods, 290, 337.— S. S. Buckman and F. A. Bather. Can the
Sexes in Ammonites be distinguished ?, 427.— F. Finn. The Significance
of the Bird's Foot, 453.
. Nature. Vol. xlix. Nos. 1253-1278. 1893-94.
J. W. Gregory. The Natural History- of East Equatorial Africa, 12.
— J. W. Judd. On a Meteorite which fell near Jarferabad in India on
April 28, 185)3, 32. — T. D. La Touche. The Erosion of Rock-basins, 39.
—A. J. Evans. The Man of Mentone, 42.— W. J. Sollas. On a Method
of separating the Mineral Components of a Rock, 211. — Anon. Neolithic
Discoveries 111 Belgium, 227.— II. F. Osborn. The Rise of the Mammalia
in North America, 235, 257. -J. W. Gregory. Mt. Kenia, 276.— Ralph
Tate. The Geology of Australia, 277. — John Milne. Earth Movements,
301. — Anon. Precious Stones, 319. — II. C. Russell. On a Meteorite
from Gilgoin Station, 325. — T. G. Bonney. Recent Publications of the
American Geological Survey, 434. — Sir Archibald Geikie. Geological
Survey of the United Kingdom, 495, 518. — Anon. The liar Dalam
Cavern and its Ossiferous contents, 514.— C. Lapworth. The Face of
the Earth, 014.
. . Vol. 1. Nos. 1279-1287. 1894.
H. J. Johnston-Lavis. The Science of Vulcanology, 66. — E. C. Stir-
ling. The Recent Discovery of Fossil Remains at Lake Calabonna,
South Australia, 184, 206.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY.
London. Palaaontographical Society. Monographs. Vol.
1893. 1893. (Two copies.)
G. J. Hinde. The Fossil Sponges. Part 3.— W. Percy Sladec
Cretaceous Echinodermata (Asteroidea). Vol ii. Part 2.— S. S,
man. The Inferior Oolite Ammonites. Part 8. — G. F. Whidborn
I>evonian Fauna of the South of England. Vol. ii. Part 3.
Photographic Society of Great Britain. Journal and
actions. N. S. Vol. xviii. Nos. 1-10. 1893-94.
Physical Society. Proceedings. Vol. xii. Parts
1893.
Boyal Agricultural Society. Journal. Ser. 3. \
Parts 2 to 4. 1893.
W. Fream. Peat and its Products, 751.
. Vol. v. Parti. 1894.
-. Royal Asiatic Society of Groat Britain and Ireland. J
Vol. xvi. Parts 1& 3. 1884.
Vol. xx. Parts 1, 3, 4. 1888.
Vol. xxi. 1889.
Vol. xxii. 1890.
Vol. xxiii. 1891.
. . . Vol. xxiv. 1892.
E. A. Floyer. The Mines of the Northern Etbai or of N
^Ethiopia, 811.
- . Vol. xxv. 1893.
— . Vol. xxvi. January and April,
-. Royal College of Surgeons of England. Calendar,
1893.
Royal Institution of Great Britain. Procc
Volxiv. Parti. (No. 87.) 1894.
Royal Geographical Society. Geographical Journal.
Nos. 1-6. 1893.
Joachim Count PfeLL South-west Africa, English and Germ
— E. Delmar Morgan. The Pevtsof Expedition and M. Bogdanc
Surveys, 65. — Th. Thoroddsen's Explorations in Iceland, 154. — Dr.
radzki s Explorations in Patagonia, 158. — F. Jeppe. The Zoutpa
Goldfielda in the South-African Republic, 213. — J. W. Gregory,
dition to Mount Kenia, 320. — Earl of Dunmore. Journeyinga
Pamirs and Central Asia, 385. — C. R. Markham. The Present
point of Geography, 481. — C. R. Markham. The Limits between G
and Physical Geography, 519.
. . . Vol. iii. Nos. 1-6. 1894.
R. D. Oldham. The Evolution of Indian Geography, 169.—
Dawson. Geographical Work in Canada in 1893, 206. — J. W. R<
194 ADDITIONS TO THE LIBRARY. [Nov. 1 894*
The Treeless Plains of the United States, 200.— B. Koto. The Great
Earthquake of Japan, 213. — D. W. Freshfield. Mountains, 228. —
K. Grossmann. Across Iceland, 261.— H. Lake. Johore, 281. — F.
von Richthofen. Count Szechenvi's Travels( in Eastern Asia, 311. —
P. Kropotkin. The Pampas, 3l6. — J. Cvijic. On the Phenomena of
Limestone Regions, 321. — A. Philippson. Northern Greece, 323. — Baron
Toll's Expedition to Arctic Siberia and the New Siberia Islands, 400.
London. Royal Meteorological Society. Quarterly Journal. VoL
xix. Nos. 87&88. 1893.
. . . Vol. xx. Nos. 89 & 90. 1894.
. Royal Microscopical Society. Journal. 1893. Parts 3-6.
1893.
F. Chapman. The Foraminifera of the Gault of Folkestone, 579.
. . . 1894. Parts 1-3. 1894.
F. Chapman. The Foraminifera of the Gault of Folkestone, 153.
. Royal Society. Catalogue of Scientific Papers (1 874-1883).
Vol.x. GIS — PET. 4to. 1894.
. . Proceedings. Vol. Mi. Nos. 323-325. 1893.
. . . Vol. liv. Nos. 326-330. 1893.
H. G. Seeley. Further Observations on the Shoulder-Girdle and
Clavicular Arch in the Ichthyosauria and Sattropterygia, 149. — H. G.
Seeley. Researches on the Structure, Organisation, and Classification of
the Fossil Reptilia. Part VIII. On further Evidences of Deuteroxiurtu
and Bhopalodon from the Permian Rocks of Russia, 168.— C. J. Forsyth
Major. On Megalodapis madagascariensis, an Extinct Gigantic Lemuroid
from Madagascar, 17G. — J. H. Cooke. The Har Dalam Cavern, Malta,
and its Fossiliferous Contents : with a Report on the Organic Remains,
274.— E. T. Newton. Reptiles from the Elgin Sandstone, 436.
• — T: ' Vol-lv- Nos. 331-333. 1894.
W. C. Williamson. Further Observations on the Organisation of the
Fossil Plants of the Coal-Measuree : Part I., 117. — C. Davison. On the
Straining of the Earth, resulting from Secular Cooling, 141— L. Fletcher.
Chemical Analysis of the Meteoric Stone found at Makariwa, near Inver-
cargill, New Zealand, in the year 1886, 142. — H. G. Seeley. Researches
on the Structure, Organisation, and Classification of the Fossil Reptilia.
Part IX. Sections 1-3, 224 & 227.
. . Philosophical Transactions for the year 18$3.
Vol. clxxxiv. A. 1894.
J. Prestwich. On the Evidences of a Submergence of Western Europe,
and of the Mediterranean Coasts, at the Close of the Glacial or so-called
Post-glacial Period, and immediately preceding the Neolithic or Recent
Period, 903.
. . . . B. 1894.
W. C. Williamson. On the Organization of the Fossil Plants of the
Coal-Measures : Part XIX., 1.— E. T. Newton. On some New Reptiles
from the Elgin Sandstones, 431.
Digitized by Google
Vol. 50.]
ADDITI0N8 TO THE LIBRAE Y.
195
London. Sanitary Institute. Transactions. Vol. xiii. 1893.
W. W hi taker. Maps showing the Area of Chalk available for Water
Supply in the Central and East parts of the London Basin, 243. — W.
Whitaker. Local Geology from a Sanitary Standpoint, 266.
. . . Vol. xiv. 1893. 1894.
. . . Vol. xv. Part 1. 1894. 1894.
. Science Progress. Vol. i. Nos. 1-4. 1894. Purchased.
A. C. Seward. Fossil Plants, 42. — A. Harker. The Evolution of
Igneous Rocks, 152. — H. A. Miers. Experiment in Mineralogy, 249. —
P. Lake. Mesozoic and Kainozoic Geology in Europe, 320.— J. E. Marr.
Recent Additions to our knowledge of the Ancient Sediments, 3/56.
Society of Arts. Journal. Nos. 2120-2145. 1893.
. . . Nos. 2146-2171. 1894.
-. Society of Biblical Archaeology. Proceedings. Vol. xv.
Part 8. 1893.
% . . Vol. xvi. Parts 1-7. 1893-94.
— — . . Transactions. Vol. ix. Part 2. 1893.
. Society of Public Analysts. Analyst. Vol. xviii. Nos. 208-
213. 1893.
. . . Vol. xix. Nos. 214-219. 1894.
. University College. Calendar. Session 1893-94. 1893.
. Victoria Institute. Journal of the Transactions. Vol. xxvi.
Nos. 104 & 105. 1893.
J. Geikie. On the Glacial Period and the Earth-movement Hypo-
thesis, 221. — Sir J. W. Dawson. Notes on Useful and Ornamental
Stones of Ancient Egypt, 265.
. Year-book of the Scientific and Learned Societies of Great
Britain and Ireland. 1893. 11th Annual Issuo. 1894.
Presented by H. Bauerman, Esq., F.O.S.
. Zoological Record. Vol. xxix. 1892. 1893. PurcJiased.
. Zoological Society. Proceedings. 1893. Parts 2-4.
1893.
C. J. Forsyth Major. On a tooth of an Ant-bear (Orycteropus) from
the Upper Miocene of Maragha (Persia), 239. — R. Lydekker. On some
Bird-bones from the Miocene of Grive-St.-Alban, Department of Isere,
France, 517. — C. J. Forsyth Major. Remarks upon a subfossil Lemuroid
skull from Madagascar, 532. — A. Smith Woodward. On the Dentition
of a Gigantic Extinct Species of Muliobatis from the Lower Tertiary
Formation of Egypt, 558. — A. Smith Woodward. On the Cranial Osteo-
logy of the Mesozoic Ganoid Fishes, Lepidotus and Dapedius, 569.
. . . 1894. Parti. 1894.
C. W. Andrews. On some Remains of JEpyorms in the British
Museum (Nat. Hist.), 108.— J. T. Last. On the Bones of the AZpyomis,
and on the Localities and Conditions in which they are found, 123.
icj6
AD LITI 053 TO THE LIBEJLBT.
[Nov. 1894,
London. Zoological Society. Transactions. VoL xiii. Part? j_ i
fc. 1893-94.
Sir E. Newton and Had* Gadow. On additional Booea of the Dodo
and other Extinct Bird* of Mauritius obtained by Han* Gadow, 2*L
— A. G. Boulenger. On Remains of an Extinct Gigantic Tortoise from
Madagascar ( Ttttudo yramdidUru, Vailknt^ 3Q£L=Rana Gadow. On
the Remain* <>( some Gigantic Land-Tortoises, and of an Extinct Lixard,
recently discovered in Mauritius, 213.
Madison. Wisconsin Academy of Sciences, Arts, and Letters.
Transactions. Vol. ix. Parts 1=2. 1892.
W. IL Hobbs. Notes on a Trip to the Li pari Islands in 1889, 2L —
W. P. Blake. The Progress of Geological Survevs in the State ol
Wiscv n^in, J^l — Ira M. IkielL Geology of the Waterloo Quartzite
AreaT 2->5.
Manchester. Literary and Philosophical Society. Memoirs and
Proceedings. Series 4. VoL vii. Nos. 2 & 3. 1S92-93.
1^3.
\V. C. Williamson. General, Morphological, and Histological Index
to the Authors Collective Memtjirs on the Fossil Plants of the Coal
Measures : Part LI^ OL
. . . -. VoL viii. Nos. 1 & 2* 1893-94.
1S94.
T. Hick. On a new S poriferous Spike from the Lancashire Coal
Measures, 2L — W. C. Williamson. General, Morphological, and Histo-
l<»trical Index to the Author's Collective Memoirs on the Fossil Plants of
the Measures : Part HL, &L
. Geol*xrical Society. Transactions. VoL xxii. Parts 9-15.
lSl'3-94.
C. E. IK* Ranee. On the Results of the Salt Union Boring at Marston,
near Northwich, "2^9. — Mark Stirrup. Further Notes on Boulders from
the Coal' Measures. 3*21 - — Mark Stirrup. Report of the Delegate to the
Brit lib Association Meeting at Nottingham, September lc©3, 4f>3- —
W. S. Gresley. Notes on Outbursts of Soft Coal and Gas, 42P.~W
Warts, Singular Nodules and Ice-worn Stones found in the Boulder
Clay of Hethorn Valley, 436.— C. E. De Ranee. On the Boring for Coal
in the Frvrb -lders' Estate at Hazel Grove, 452.— G. IL Kinahan. On
the Iron Ore Measures of Countv Antrim, 4T>8.
Melbourne. Roval Society of Victoria. Proceedings. New Series.
Vol. iv. Part ± 1892.
. . . . Vol. v. 1893.
A. W. Cresswell. Notes on the Lilydale Limestone, 3fL — G. Officer
and L. Balfour. Preliminary Account of the Glacial Deposits of Bacchus
Marsh, 45. — T. S. Hall. On two new Tertiary Stylasterids, 112.
. . . . Vol. vi. 1894.
T. S. Hall and G. B. Pritchard. Notes on the Eocene Strata of the
Bellarine Peninsula, with brief references to other deposits, L — E. J.
Dunn. Glaciation of the Western Highlands, Tasmania, 133,— -G. Officer
and L. Balfour. Further Note on the Glacial Deposits of Bacchus Mar>b,
130. — R. Etheridge, J un. An Operculum from the Lilydale Limestone,
150. — A. W. Cresswell. Additional Notes on the Lilydale Limestone
l"j<i— R. Etheridge, Jun. The largest Australian Trilobite hitherto dis^
covered, 189.
VoL 50.]
ADDITIONS TO THE LIBRARY.
197
Mexico. Sociedad Mexicans de Historia Natural. La Naturaleza.
Serie 2. Tomo i. Nos. 1-10. 1887-91. Presented by C.
Dairies Sherborn, Esq., F.G.S.
A. Duges. Platygonw Aletnanii, nobis. Fosil cuaternario, 16. — M.
M. Villada. Resumen de una parte del estudio de los Sres. A. Dollfus
y E. de Montserrat, 36. — G. B. ruga. Resena de una exploracion geo-
logica en el Estado de Veracruz, 49. — M. M. Villada. La Caverna de
Ojo de Agua, 81. — M. M. Villada. Relacidn de un viaje a la Caverna de
Cacahuamilpa, 148. — G. R. Puga. Resena geoMgica de la Sierra de Guada-
lupe, Valle ae Mexico, 107. — M. Barcena. Informe sobre el estado actual
del Volcan de Colima, 249. — A. del Castillo. Catalogo descriptivo de
los Meteoritos (Tierras y Piedras Meteoricas) de Mexico, 378. — W. E.
Hidden. Ampliaciones al Catalogo Anterior. 384. — G. F. Kunz. Meteo-
rito de Catorce San Luis Potosi, 392. — E. D. Cope. Informe sobre los
criaderos de carbon de piedra de Zacualipam, Estado de Hidalgo, 393. —
E. D. Cope. Hippotherium peninsulatum, sp. nov., y Protohijtpus Cas-
tilli, sp. nov., 895. — M. Herrera y Gutierrez. La Dolomia del Distrito
de Uruapam, 397. — M. M. Villada. Apuntes de geologia y de botanica
relativos a Mexico, 419, 493. — G. B. Puga. El Cerro de la Estrella 6 de
Ixtapalapa, 488. — M. M. Villada. La variedad mas notable de Granate
Mexicano, 500— E. Ordonez. El Pedregal de San Angel, 502.--N. T.
Lupton and C. U. Shepard. Informes sobre Meteoritos de Mexico to-
rnados de publicacionew Norteamerieanas, 504, 505.
-. . . . Tomo ii. Nos. 1-4. 1891 and
1892. Presented by C. Davies Sherbomy Esq., F.Q.S.
G. B. Puga. Apuntes para la geologia del Valle de Mexico, 86. —
M. Barcena. Apuntes relativos a la geologia del Estado de Jalisco, 198.
Milan. Giornale di Mineralogia, Cristallografia e Potrografia.
Vols, i.-iii. 1890-92.
. . Vol. iv. Fasc. 1-4. 1893.
C. Somigliana. Intorno da un problema del Signor Voigt, 1. — E.
Artini. Appunti petrografici sopra alcune roccie italiane, 7. — F. Sansoni.
Sulla serpentina d'Oira (Lago d'Orta) 0 sopra alcune roccie ad essa
associate, 16. — A. Ricco e G. Mercalli. Sopra il periodo eruttivo dello
Stromboli cominciato il 24 Giugno 1891, 25. — C. Kiva. Studio cristal-
loarafico di alcune sostanze organiche, 29. — J. Chelussi. Alcune roccie
dell' isola di Samos, 33. — G. Melzi. llicerche geologiche e petrografiche
sulla valle del Masino, 89. — G. Casella. Diabase uralitizzata od epidio-
rite della Torre del Romito nei Monti Livornesi, 137. — G. Bartalini.
Sulla determinazione delle proprieta ottiche dei cristalli mediante tre
prismi di orientaziono qualunque, 145. — P. Franco. Sull' Aftalosa del
Vesuvio, 151. — C. Viola. Sopra un problema relativo alle lamine sottili
anisotrope, 173. — P. Franco. Studi sull' Idocrasia del Vesuvio, 185. —
C. Riva. Sopra alcune rocce deJla Val Sabbia, 195. — G. Gianotti.
Nuovi appunti petrografici sopra alcune Roccie del Hano del Re (Monte
Viso), 211.— A. Verri ed E. Artini. Le formazioni con ofioliti nell*
Umbria e nella Valdichiana, 244. — J. Chelussi. Studio petrografico di
alcune arenarie della provincia di Aquila, 277. — J. Chelussi. Appunti
petrografici sopra alcune roccie della provincia di Parma, 283.
-. Society Italiana di Scienze Naturali. Atti. Vol. xxxiii.
Fasc. 1 & 2. 1890 and 1891.
L. Ricciardi. Ricerche sulle sabbie delle coste Adriatiche e sulle
cause dell' interrimento del porto di Bari, 41. — C. F. Parona. I fossili
del Lias inferiore di Saltria in Lombardia, 91.
198
ADDITIONS TO TDK LIBRARY.
[Nov. 1894,
Minneapolis. American Geologist. Vol. xii. Nos. 1-6. 1893.
F. L. Nason. Notes on some of the Iron-bearing Rocks of the Adi-
rondack Mountains, 26. — A. S. Eakle. On some Dykes occurring near
Lyon Mt., Clinton Co., N.Y.. 81.— VV. Upham. Englacial Drift, 30.—
S. S. Buckman and F. A. Bather. The Terms of Auxology, 43. — R. R.
Rowley. Range of Chouteau Fossils, 49. — C. S. Beacher. Erosions of
small Basins in North-western Indiana during the time preceding the
Pleistocene Period, 62. — S. Calvin. On the Structure and probable
Affinities of Cerionite* Dactylioides, Owen, 63. — J. Moore. The recently
found Castoroides in Randolph County, Indiana, 07. — G. C. Broadhead.
A critical notice of the Stratigraphy of the Wisconsin Paleozoic, 74. —
E. W. Claypole. The three Great Placodenns of Ohio, 89. — C. R.
Keyes. The Unconformity of the Coal Measures and the St. Louis Lime-
stone in Iowa, 99.— S. Calvin. Notes on some Fossil Corals described by
D. D. Owen in his Report of work done in the Autumn of 1859, with
Observations on the Devonian Species PhiUipastrea gigas of later Authors,
108.-^1. M. Clarke. The Protoconch of Orlhoceras, 112. — A. F. Foerste,
An Examination of Glyptodcndron, Claypole, and of the other so-called
Silurian land-plants of Ohio, 133. — F. L. Nason. " The co rrect succes-
sion of the Ozark series " : a renew reviewed, 141.— R. S. Tarr. Glacier
Erosion, 147. — S. II. Perry. A Classification of Topographic Forms, 153.
— J. Eyerman. On a collection of Tertiary Mammals from Southern
France and Italy; with brief descriptions thereof, 159.— Pleistocene
papers at the Madison Meetings [(Geological Society of America and
American Association for the Advancement of Science], 165. — Leo
Lesquereux. The Genus WincheUia, 200. — A. Lindenkohl. Mount St.
Elias in Alaska and Mount Orizaba in Mexico, 213.— W. H. Hobla.
New occurrences of parallel intergrowths of the minerals Allanite an 1
Epidote, 218.— H. V. Winchell. Note on Cretaceous in Northern Min-
nesota, 220.— Reviews of the Ice Age at the World's Congress on
Geology, 223.— F. G. Plummer. A diagonal Moraine, 231. — A. F.
Foe rate. Remarks on specific characters of OrtAoctrcu, 232. — W. P.
Blake. The mineral deposit* of South-west Wisconsin, 237. — T. H.
Macbride. A new Cycad {Bennettites dacotetutis, Macbride), 248. —
E. W. Claypole. On three new Species of Dinichthys, 275. — J. B.
Woodworth. An attempt to estimate the thickness of the Ice-blocks
which gave rise to Lakelets and Kettle-holes, 279. — E. H. Mudge.
Observations along the Valley of Grand River, Michigan, 284. — H.
Ilerzer. A new Fungus from the Coal Measures, 289. — A. Hyatt The
Terms of Bioplaatology, 290. — R. Rowley. Description of "some new
Species of Crinoids, Blastoids, and Branchiopods from the Devonian and
Sub-Carboniferous Rocks of Missouri, 303.— E. T. Dumble and W. F.
Cummins. The Kent section and Gryphaa Tucumcarii, Marcou, 309. —
O. II. Hershev. The Pleistocene rock-gorges of North-western Illinois,
314. — C. D. Walcott. Geologic Time ; as indicated by the Sedimentary
Rocks of North America, 343.— W. O. Crosby. The Origin of Parallel
and Intersecting Joints, 368.
Montreal. Natural History Society. Canadian Record of Science.
Vol. v. Nos. 6 and 7. 1893.
J. F. Whiteaves. Notes on the Gasteropoda of the Trenton Limestone
of Manitoba, etc., 317. — J. T. Donald. Some Misconceptions concerning
Asbestos, 329. — Coleman. The Rocks of Clear I>ake, near Sudbury,
843. — W. L. Goodwin. Notes from the Laboratory, Queen's University,
347. — G. F. Matthew. On some New Discoveries in the Cambrian Be<ls
of Sweden, 361. — R. Helmhacker. Discovery of Platinum in Place in
the Ural Mountains, 366.— Sir J. W. Dawson. Geological Notes, 386.—
W. A. Carlyle. Notes on a Great Silver Camp, 403.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
199
Moscow. Socie*te Impe'riale des Naturalistes. Bulletin. 1893.
N.S. Tomevii. Nos. 2-4. 1893-94.
0. Retowski. Die tithonischen Ablagerungen von Theodosia. Ein
Beitrag zur Palaontologie der Krim, 206. — A. P. Ivanoff. PalflRonto-
logical contributions on the Surmatian of Southern Podolia from Vertical
Sections, 303 [In Russian]. — W. Stchirowaky. Ueber Ammoniten der
Genera Oxynoticeras und Hoplites aus dem nord-simbirsk'schen Neocom,
309.
. . . 1894. N.S. Tomeviii. No. 1. 1894.
Munich. Koniglich-bayerische Akademie der Wissenschaften.
Abhandlungeu der mathematisch-physikalischen Classe. Band
xvii. Abth. 3. 1892.
. . . Band xviii. Abth. 1 & 2. 1893.
II. Pohlig. Eine Elephantenhohle Siciliens und der erste Nachweis
des Craninldomes von Elephas antiquus, 73. — J. G. Egger. Foramini-
feren aus Meeresgrundproben, gelothet von 1874 bis 1876 von S. M. Sch.
« Gazelle/ 193.
. . Sitzungsberichte der mathematisch-physikalischen
Classe. 1893. Hefte 2-3. lJ?93-94.
K. A. von Zittel. Die geologische Entwickelung, Herkunft und Ver-
breitung der Saugethiere, 137. — F. v. Sandberger. Das Erzvorkommen
von Cinque valle bei Roncegno im Val Sugana ca. 30 km ostlich von
Trient, 109. — W. von Giimbel. Die Amberger Eisenerzformation, 293.
. . . 1894. Heftl. 1894.
. See Books : Bavaria.
Nancy. Academic do Stanislas. Memoires, 1892. Serie 5.
Tome x. 1893.
Newcastle-under-Lymo (Stoke-npon-Trent). North Staffordshire
Institute of Mining and Mechanical Engineers. Proceedings.
Vol. xii. Parts 4 & 5. 1893.
Newcastle-upon-Tyne. Durham College of Science. Calendar.
Session 1893-94. 1893.
. North of England Institute of Mining and Mechanical
Engineers. Annual Report for the Year 1892-93. 1893.
. . Transactions. Vol. xlii. Parts 4 & 5. 1893-94.
E. Halse. The Gold-bearing Veins of the Organos District, Tolima,
U.S. Colombia, 259.
. . . Vol. xliii. Part t. 1893.
E. liaise. Note on the occurrence of Mercury at Quindice, Tolima,
U.S. Colombia, 27.
. . . Vol. xliii. Part 2. 1893.
E. Halse. Note on the Antimony Deposit of El Altar, Sonora,
Mexico, 98.
T0L. L. 2
200 ADDITIONS TO THE LIBBART. [Nov. 1894,
Newcastlo-upon-Tyne. North of England Institute of Mining and
Mechanical Engineers. Transactions. Vol. xliii. Part 3.
lsy3. 18<J4.
J. P. Kirkup. Singareni Coal-field, Hyderabad, India, 179. — A. L.
Collins. The Ghorband Lead-mines, Afghanistan, 207.
, . Vol. xliii. Part 4. 1893.
. . An account of the Strata of Northumberland and
Durham as proved by Borings and Sinkings. S-T. 8vo.
1894.
. See Barnsley.
New Haven, Conn. American Journal of Science. Series 3. Vol. xliv.
No. 262. 1892. Purchased.
C. L. Whittle. On an Ottrelite-bearing phase of Metamorphic Conglo-
merate in the Green Mountains, 270. — J. S. Diller. Mica-peridotii*
from Kentucky, 286.— D. F. Lincoln. Glaciation in the Fingwr-Lato
Region of New York, 290. — O. C. Marsh. Restoration of Ciaaosanrw
and Crratomurv*, 342. — O. C. Marsh. Restoration of Mastodon anwri-
canu*, Cuvier, 350.
— . . Vol. xlvi. Nos. 271-276. 1893.
W. P. Headden. Kehoeite, a new Phosphate from Galena, Lawrence
Co., S.D., 22.— E. T. Dumble and G. D. Harris. The Galveston Deep
Well, 88. — G. H. Williams. Piedmontite and Scheelite from the
Ancient Rhvolite of South Mountain, Pennsylvania, 50. — G. C. Broad-
head. Cambrian and. Ozark Series, 67.— E. E. Howell. Cross Roads
Meteorite, 67.— W. E. Hidden and W. F. Hillebrand. Mackintosh/te, a
new Thorium and Uranium Mineral, 98. — C. H. Smyth, Jun. Alnoite
containing an uncommon Variety of Melilite, 104. — S. L. Penfield. Cau-
fieldite, a new Germanium Mineral, and on the Chemical Composition of
Argyrodite, 107.— W. Upham. Epeirogenic Movements associated with
Glaciation, 114. — W. D. Matthew. Antennae and other Appendages of
Trutrthrus Beckii, 121. — G. F. Becker. Fisher's New Hvpothesis, 1J*7. —
C. Barus. Criticism of Mr. Fisher's Remarks on Rock Fusion, 140. —
C. E. Beecher. Larval forms of Trilobites from the Lower Helderburg
Group, 142.— W. S. Bavley. Actinolit»»-Magnetite Schists from the
Mesa to Iron Range, in North-eastern Minnesota, 176. — W. Lindgren.
The Auriferous Veins of Meadow Lake, California, 201.— W. E. Hidden
and W. E. Hillebrand. Description of Rowlandite, 208.— C. S. Pros**-
The Upper Hamilton and Portage Stages of Central and Eastern New
York, 212. — A. F. Foerste. Studies on the Chipola Miocene of Bwn-
orre-
e umpc
bridge, Georgia, and of Alum Bluff, Florida, with an attempt at corre-
lation of certain Grand Gulf group beds with marine Miocene Ms
eastward, 244.— W. E. Hidden. Mineralogieal Notes, 254. — B. Willis and
C. W. Hayes. Conditions of Appalachian Faulting, 257. — L. G. Eakina.
— A New Meteorite from Hambien County, Tennessee, 283. — H. 8.
Williams. On the Ventral Plates of the Carapace of the genus Solon***
of Newberrv, 285.— S. L. Penfield. Minerals from the Manganese Mines
of St. Marcel, in Piedmont, Italy, 288.— O. C. Marsh. Restoration of 0*T.
phodon, 320. — J. D. Dana On New England and the Upper Mississippi
basin in the Glacial period, 827. — J. J. Stevenson. On tne Use of the
Name " Catskill," 330. — G. F. Becker. The Finite Elastic Stress-Strain
Function, 337.— G. A. Koenig and L. L. Hubbard. On Powellite from
n now Locality, 357.— L. V. Pirsson. On the Geolojry and Petropapnj
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
201
of Conanicut Island, R.T., 363. — C. E. Beecher. A Larval Form of
Triarthrus, 378. — II. P. Osborn. The Rise of the Mammalia in North
America, 379. — O. C. Marsh. Description of Miocene Mammalia, 40(5. —
Carey Lea. On Endothermic Decompositions obtained by Pressure,
Part II., 413. — II. A. Miers. Quartz from the Emerald and Hiddenite
Mine, North Carolina, 420. — A. F. Foerste. New fossil localities in the
early Palaeozoics of Pennsylvania, New Jersey, and Vermont, with
remarks on the close similarity of the lithologic features of these Palneo-
zoics, 435. — R. Pumpelly. An apparent Time-break between the Eocene
and Chattahoochee Miocene in South-western Georgia, 445. — II. F.
Osborn. Rise of the Mammalia in North America, 448.— -C. E. Beecher.
On the Thoracic Legs of TrUirthnu, 407. — G. F. Kunz and O. W. Hun-
tingdon. On the Diamond in the Canon Diablo Meteoric Iron and on
the hardness of Carborundum, 470.
New Haven, Conn. American Journal of Science. Series 3.
Vol. xlvii. Nos. 277-282. 1894.
S. F. Peckham. Petroleum in its relations to Asphaltic Pavement,
29. — E. H. Williams, Jun. The Age of the extra-moraine fringe in
Eastern Pennsylvania, 34. — C. D. Walcott Notes on the Camorian
Rocks of Pennsylvania, from the Susquehanna to the Delaware, 37. —
J. B. Woodwoirth. Post-Glacial /Eolian Action in Southern New
England, «>3.— S. II. Scudder. The Carboniferous Insects of Comraentrv,
France, 90. — H. B. Bashore. The Harrisburg Terraces, 98. — R. t.
Dodge. Additional Species of Pleistocene Fossils from Winthrop, Mass.,
100. — D. F. Lincoln. The amount of Glacial Erosion in the Finger-
Lake Region of New York, 105. — II. S. Washington. On the Basalts of
Kulu, 114. — W. Upbam. The Fishing Banks between Cape Cod and
Newfoundland, 123. — G. F. Wright Continuity of the Glacial Period,
101. — S. L. lVntield and W. T. II. Howe. Chemical Composition of
Chondrodite, Ilumite, and Clinohumite, 188. — J. W. Spencer. Defor-
mation of the Lundy Beach and Birth of Lake Erie, 207. — L. V. Pirssou.
Crystallization of Enargite, 212. — II. L. Smyth. Relations of the Lower
Menominee aud Lower Marguette Series in Michigan, 216. — O. C.
Marsh. Restoration of Camptotaums, 245. — T. C. Chamberlin and F.
Leverett. Further Studies of the Drainage Features of the Upper
Ohio Basin, 247. — E. A. Smith. Post-Eocene Formations of the Coastal
Plain of Alabama, 285. — R. L. Packard. Variscite from Utah, 297. —
C. E. Beecher. Appendages of the Pygidium of Triarthrwt, 24)8. —
G. D. Harris. Geological Position of the Eocene Deposits of Maryland
and Virginia, 301. — S. L. Penh'eld. Contributions to the Crystallization
of Willemite, 305. — C. D. Walcott. Occurrence of OlencUw in the
Gn?en Pond Mountain Series of Northern New Jersey, with a Note on
the Conglomerates, 30$). — T. L. Walker. Notes on Nickeliferous Pyrite
from Murray Mine, Sudbury, Ont, 312. — S. L. Penfield. On the Crys-
tallization of Herderite, 329. — J. F. Kemp. Additional Note on Leucite
in Sussex Co., 339. — L. V. Pirsson. On some Phonolitic Rocks from the
Black Hills, 341.— C. L. Whittle. The General Structure of the Main
Axis of the Green Mountains, 847. — J. E. Wolff. Notes on Apparatus
for the Geological Laboratory, 355. — W. Upham. Diversity of the
Glacial Drift along its Boundary, 358. — W. Libbey, Jun. Gases in
Kilauea, 371.— S. L. Pentield and J. C. Minor, Jun. On the Chemical
Composition and Related Physical Properties of Topaz, 387. — O. C.
Marsn. Restoration of Efotherium, 400.— O. C. Marsh. A New Miocene
Mammal, 409. — A. Agassiz. Notes from the Bermudas, 411. — J. S.
Diller and C. Schuchert. Discovery of Devonian Rocks in California,
410.— E. E. Howell. Beaver Creek* Meteorite, 430.— A. S. Eakle. Al-
92
202
ADDITT053 TO THE LIBRARY.
[Nov. 1894,
lanite Crystals from Franklin Furnace, N.J., 436.— S. L. Penfield.
Argvrodite and a new Sulphoatannate of Silver from Bolivia, 451.—
H. \V. Turner. Notes on the Gold Ores of California, 467.— A. H.
Phillips. Recent analysis of Pele's Hair and a Stalagmite from the lata
Caves of Kilauea, 473.
New York. American Institution of Mining Engineers,
actions. tSu Easton, Pa.
. American Museum of Natural History. Annual Report for
the Year 1891. 1892.
. . Annual Report for the Year 1892. 1893.
. . Bulletin. Vol. v. 1893.
J. L. Wortman. On the Divisions of the White River or Lower
Miocene of Dakota, 96. — J. L. Wortman and C. Earle. Ancestors of
the Tapir from the Lower Miocene of Dakota, 169. — H. F. Osborn.
Fossil Mammals of the Upper Cretaceous Beds, 311.
. . Memoirs. Vol. i. Part 1. 1893.
R. P. Whitfield. Republication of descriptions of Lower Carboni-
ferous Crinoidea from the Hall Collection now in the American Museum
of Natural History, with illustrations of the original Type Specimens
not heretofore figured, 1.
. Academy of Sciences. Annals. Vol. vii. Nos. 1-12.
1893-94.
J. F. Kemp and A. Hollick. The Granite at Mounts Adam and Eve,
Warwick, Orange Co., N.Y., and its Contact Phenomena, 6H8.
. . . Vol. viii. Nos. 1-3. 1893.
A. A. Julien. A Study of the New York Obelisk as a Decayed
Boulder, 93.
. . Transactions. Vol. xii. 1892-93. 1893.
J. F. Kemp. A. Review of work hitherto done on the Geology of the
Adirondacks, 19. — A. Hollick. Additions to the Paleobotany" of the
Cretaceous Formation on Staten Island, 28. — H. Ries. Notes on the
Clays of New York State and their Economic Value, 40.— G. S. Hun-
tington. On the Ileo-colic Junction in Procyon lotor and Allied Forms,
60. — J. F. Kemp. On an occurrence of Gabbro (Norite), near Van
Artedalen's Quarry, Bucks County, Pennsylvania, 71. — C. H. Smyth. A
Geological Reconnoissance in the vicinity of Gouverneur, N.Y., 97. —
W. D. Matthew. On Phosphate Nodules from the Cambrian of Southern
New Brunswick, 108.— B. Dean. Note on the Mode of Origin of the
Paired Fins, 121. — H. F. Osborn. The Evolution of Teeth in Mammalia
in its bearing upon the Problem of Phylogeny, 187. — A. Hollick. Plant
Distribution as a Factor in the Interpretation of Geological Phenomena,
with t-pecial reference to Long Island and Vicinity, 189. — C. H. Smyth,
Jun. Petrography of the Gneisses of the Town of Gouverneur, N.Y„ 203.
C. F. Cox. On recently discovered Deposit* of Diatomaceous Earth in
the Adirondacks, 210. — A. Hollick. Preliminary Contribution to our
Knowledge of the Cretaceous Formation on Long Island and Eastward
. Science. Vol. xxi. Nos. 518-S43. 1893. PremUd bu
tU Ktv. J. F. Blakt, F.G£. 9
. — • Vol ixii. Nos. 545-569. 1S93. PrtttnUd by
th< R<v. J. F Blake, F.GJS. 9
Vol. 50.]
ADDITIONS TO THE LIBRARY.
Northampton. Northamptonshire Natural History Society. Journal.
Vol. vii. Nob. 53-56. 1893.
B. Thompson. Geological Notes, 254.
Oporto. Sociedade Carlos Ribeiro. Revista de Sciencias Naturaes
e Sociaes. Vol. ii. No. 8. 1893.
A. Bensaude. 0 diamante, 159.
. . - — . Vol. iii. No. 9. 1894.
Wenceslau de Lima. Sobre uma especie critica do Rothliegendes, 1.
Ottawa. Royal Society of Canada. Proceedings and Transactions
for the year 1892. Vol. x. 1893.
Section III.
E. J. Chapman. On the Mexican Type in the Crystallization of the
Topaz, 25.
Section IV.
G. F. Matthew. On the Diffusion and Sequence of the Cambrian
Faunas, 8. — E. J. Chapman. On the Corals and Coralliform Types of
Palneozoic Strata, 39. — Sir J. William Dawson. On the Correlation of
Early Cretaceous Floras in Canada and the United States, 79. — G. F.
Matthew. Illustrations of the. Fauna of the St. John Group, No. VII.,
95. — J. F. Whiteaves. Notes on the Ammonites of the Cretaceous
Rocks of the District of Athabasca, with Descriptions of Four New
Species, 111.
Pudua. Reale Accademia di Scienze, Lettere ed Arti. At ti e Memorie.
Anno cclxxxix. 1887-88. Nuova Serie. Vol. iv. 1888.
A. Keller. Ancora sui Fosfati, 370.
. . . Anno ccxciv. Nuova Serie. Vol. ix.
1892-93. 1893.
. Rivista di Mineralogia e Cristallografia Italiana. Vol. xii.
Fasc. 1-6. 1892-93. Purchased.
G. B. Negri. Sopra le forme cristalline della Baritina di Monte-
vecchio (Sardegna) e di Millesimo (Liguria), 3. — L. Bucca. Studio
petrografico sulle trachiti leucitiche del lago di Bolsena, 18. — G. Struever.
Sui minerali del granito di Alzo, 49. — E. Billows. Su d'un vistoso cris-
tallo di Vesuvianite, 65. — A. Bartoli. Sui calore specitico fino ad alta
temperature di alcune roccie della Sicilia, 56. — A. Bartoli. Sulla tempe-
rature delle lave dell' attuale eruzione dell' Etna, 61.— >G. Struever.
Sopra alcune miche del Lazio, 81. — G. Vacca. Sopra un note vole
cristallo di Vesuvianite, 88.
. . Vol. xiii. 1893. Purchased.
G. La Valle. Sulla Marcasite rinvenuta al Capo Schina preaso Gioiosa
Marea in Sicilia, 3. — L. Bucca. Riproduzione artificinle della pint*
magnetica, 10. — L. Bucca. Sopra una nuova localita di ferro ohgisto
dell' Etna, 12. — L. Busatti. Alcune rocce delle pendici Nord-Occidentnli
della Sila (Calabria), 17. — G. Piolti. II calcare del Gran Roc (Alta
vnlle di Su*a), 24. — L. Busatti I Porfidi della Miniera di Tuviois nel
Sarrabus (Sardegna), 33. — L. Busatti. Contribuzioni chimico-minera-
logiche e petrogratiche, 51.
■ . . Vol. xiv. Fasc. 1 & 2. 1894. Purchased.
F. Graff a R. Brauns. Contribuzioni alia conoscenza delle rocce
eruttive granulari di Cin^olina sugli Euganei preaso Padova, 17. —
G. Boeris. Sopra la calcocite di Montecatini, 26.
204
ADDITIONS TO THE LIBRARY.
[Nov. i $94,
Palermo. Annates do Geologic et do Paleontologie. lle livraison.
1803.
March. Antonio de Gregorio. Iconografia Conchiologica Mediterranea
vivente e Terziaria. III. Fascicolo, 1.
Paris. Academic des Sciences. Comptes-rendus. Tome cxvii.
1893.
E. Bureau. Sur les pr&endues Fougeres fossiles du calcaire grassier
parisien, 201. — A. Julien. Sur l'origine glaciaire des brechea des wissin*
houillers de la France centrale, 256. — S. Meunier. Sur deux me^oritt*
turqnes recemment parrenues au Museum d'Histoire natui-elle, 257.—
A. Daubree. Couches a pdtrole des environs de Pechelbronn (Basse-
Alsace) ; temperatures exceptionnellement dlevdes qui s'y nianifestent, 26o.
— A. Julien. Sur la gtfoge'me et la stratigraphie des bassins houillers de la
France centrale, 344. — P. De Rouville, A. Delage, et J. Miguel. Cambrien
de l'Herault, 346.— Bateau. Hypothese des cloches sous-continentals,
370. — M. Lugeon. Sur une dislocation en forme de champignon, dana
les Alpes de la Haute-Savoie, 564. — A. E. Nogues. Fractures des ter-
rains a charbons du sud du Chili, 592.— C. E. Bertrand et B. Renault.
Caracteres gene*raux des ' bogheads' a Algues, 593.— G. de Saporta. Sur
une couche a Nymphelne'es, reremnient explore et comprise aans l'aqui-
tanien de Manosque, 607. — M. Boule et P. Glangeau. Le CallibracMo*%
nouveau reptile du permien d'Autun, 646. — A. F. Nogues. Les pheno-
menes glaciaires et erratioues dans le vallon du Cachapoal (Cordillere des
Andes du Chili), 648. — W. Kilian. Secousse de trembleraent de terre a
Grenoble, 650. — L. Duparc et L. Mrazeo, Sur rextrdmite' nord-est du
massif du Mont Blanc, 705. — H. Sehardt. Sur 1'oriffine des Alpes du
Chablais et du Stockhorn, en Savoie et en Suisse, ^07. — P. Girod et
E. Massenat. Decouverte (Tun nouveau depot pr^historique magdalenien
dans la valine de la Vezere, 709. — A Badoureau. Preuves et cause du
mouvement lent actuel de la Scandinavie, 767. — Stanislas Meunier. " Ob-
servations sur le calcaire oolithique supexieur au gypse de Villejuif, pre*
Paris, 769. — P. de Rouville, A. Delage, et J. Miquel. Sur les terrains
primaires de rarrondiasemeut de Saint-Pons (H6rault), 818. — H. Nolan.
Sur les terrains trinsicjue et jurassiquedesilesBaie'arc8,821. — F. Gonnard.
Sur l'olivine de Maillarques, pies d'Allanche (Cantal), 864. — A. E.
Nogues. Eruption du volcan Calbuco, 866.— O. Lienier. BenHtitet
Morierei, fruit fossile presentant un nouveau tvpe d'innorescence gymiio-
sperme, 867.— G. F. Dollfus. Sur les lite oolithiques du tertiaire
parisien, 1113.
. . . Tome cxviii. Nos. 1-26. 1894.
P. W. Stuart-Menteath. Sur les ophites des Pyrenees occidentale*,
32. — A. Milne-Edwards et A. Grandidier. Observations sur les A'/f
amis de Madagascar, 122. — A. Julien. Sur le synchronisme des baasins
houillers de Commentry et de Saint-Etienne, et sur les consequences qui
en decoulent, 155. — O. Lignier. Sur l'^piderme des pldoncules senuni-
feres et des grains chez le BenneUite* Morierei (Sap. et Mar.), 158.—
Marcel Bertrand. Sur la structure des Alpes francaises, 21 2. — P. Zurcber.
Sur les lois des plissements de l'ecorce terrestre, 215.— Marcel Bertrand.
Lignes directrices de la geologie de la France, 258. — H. Le Chatelier.
Sur la constitution des calcaires marneux, 262. — A. lnostranzeff. Sur
les formes du platine dans sa roche mere de l'Oural, 264. — P. Girod et
P. Gautier. Sur l'age du squelette humain decouvert dans les formations
eruptivea de Gravenoire (Puy-de-D6me), 265. — A. de Grossouvre. Sur
les relations entre les transgressions marines et les mouvements du sol,
301.— G. Holland. Sur les chances d'obtenir des eaux artesiennes le Ion?
Digitized by Googl
<
iTol. 50.] ADDITIONS TO THE LIBRARY 205
le l'oued Igharghar et de l'oued Mya, 303. — H. Moissan. Nouvelles ex-
>eYiences sur la reproduction du dianiant, 320. — B. Renault. Sur
luelques parasites des L^pidodendrons du Culm, 3(55. — Stanislas Meunier.
)bservations sur la constitution de la roche mere du platine, 3(38. —
Li, Gentil. Sur un giseuieut d'apophyllite des environs de Collo (Algene),
U59. — A. F. Nogues. Eruption du volcan Calbuco, 372. — A. Issel.
liemarques sur les tremblements de terre subis par Tile de Zante pendant
'annee 1893, 374. — A. Lacroix. Sur quelques inmeraux de la Xouvelle-
1'aleclonie, 551. — L. Duparc et A. Delebecque. Sur les gabbros et les
miphibolites du massif de Belledonne, 673. — £. Haug. J^es zones tecto-
liques des Alpes de Suisse et de Savoie, 675. — A. de Gramont. Sur les
uectres d'tStincelle de quelques mindraux, 746. — C. Deperet. Sur un
risenient siderolithique de Mammiferes de l'eocene moyen, a Lissieu,
>r6s Lyon, 822. — K. Harle\ Decouverte d'ossements dllyenes raye"es
lans la grotte de Montsaunes (Haute-Garonne), 824. — Bleicber. Sur la
•tructure de certaines rouilles; leur analogic avec celle des minerals de
er sddimentaires do Lorraine, 887. — P. Fliche. Sur des fruits de
'almiers trouvfo dans le cCnoinanien aux environs de Sainte-Menehould,
*89. — Stanislas Meunier. Recherches sur un mode de striage des roches
nde"pendant des ph«§nomenes giaciaires, 890. — A. Gaudry. Sur les
bssiles recueillis a Montsaunes, 907. — A. Grandidier. Du sol et du climat
le Tile de Madagascar au point de vue de l'agriculture, 952. — A. Caruot.
Sur la composition chimique des waveilites et des turquoises, 995. —
L. Gentil. Sur la microstru^ture de la melilite, 998. — Stauislas Meunier.
UemarquB relative a une recente Communication de M. Issel sur les
remblements de terre de Tile de Zante, 1011. — £. Ficheur. Le bassin
iacustre de Constantine et les formations oligocenes en Algerie, 1066. —
3. Brongniart. Les insectes de 1'tSpoque carbonifere, 1128. — G. Holland.
Sur l'accroissement de temperature des couches terrestres avec la pro-
fondeur dans le bas Sahara algerien, 1164. — C. Friedel. Sur la compo-
sition de l'apophyllite, 1232. — A. Pomel. Decouverte de Champsosauriens
lans les gisements de phosphorite du suessionien de l'Alge>ie, 1309. —
P. W. Stuart-Menteath. Sur les li<?nes geologiques des environs de
I'observatoire d'Abbadia (Basses-Pyrenees), 1363.— A. Pomel. Sur le
Dyrosauru* theveslensis, 1396. — L. Cayeux. Sur la presence de restes de
Foraminiferes dans les terrains pre'canibriens de Bretagne, 1433.
Paris. Annolcs des Mines. Serie 9. Tome iii. 6" livraison de
1893.
Memoires.
G. Chesneau. LTndustrie des Iluiles de Schiste en France et en
lieosse, 617.
. . . Tome iv. 7'-12* livraisons de 1893.
Mimoire*.
A. Carnot. Minerals de manganese analyses au bureau d'essai de
l'Ecole des mines de 1845 a 1893, 189.
Bulletin.
L. de Launav. Decouverte de nouveaux gisements d'or a Coolgardie
(Australie Occidentale), 595.
. . . Tomov. lw-5e livrasions de 1894. 1894.
MS moires,
A. Gautier. Sur un gisement de phosphates de chaux et d'alumine
contenant des especes rares ou nouvelles et sur la genese des phosphates
206 ADDITIONS TO THE LIBRARY. [NOV. 1894,
et nitres naturels, 5. — Riche et Roume. L'industrie du p^Strole »ui
Etate-Unis d'Amenque, 67.— L. de Launay. Lea eaux minexales de
Pfaefers-Rajratz (Canton de Saint-Gall, Suisse), 188.— L. de Launay. L<&
richesses minerales de la Nouvelle-Zglande, 523.
Bulletin.
Wiener. Lee Mines d'Argent d'Oruro (Bolivie), 611.
Paris. Annales des Sciences Naturelles. Zoologie et Faleon-
tologie. Bene 7. Tome xiv. Nos. 1-3. 1892. Purchased.
. . . Tome xv. Nob. 2 & 3. 1893.
Purchased.
M. Boule. Description de YHyana brtvirostris du Pliocene de Sain-
relles, pres le Puy, Haute-Loire, 85.
. . . . . Nos. 4-6. 1893. Pur-
chased.
. . . Tome xvi. Nos. 1-3. 1893. Purchased.
H. Filhol. Observations concernant quelques mammiferes fossiles
nouveaux du Quercy, 129. — A. Grandidier et H. Filhol. Observations
relatives aux ossements d'Hippopotaxues trouves dans le marais d'Ambo-
lisatra a Madagascar, 151.
Nos. 4-6. 1894. Purchased.
— . Tome xvii. Nos. 1-3.
1894. Purchased.
. Annuaire Geologique UniverseL Annee 1892. Tome ix
Pasc. 1-4. 1893-94.
— . Association Francuse pour l'avancement des Sciences.
Compte-rendu de la 19me Session. Limoges, 1890. ln Partie*
Documents Ofiiciels et Proces-verbaux. 1890. Purchased.
. . . . 2* Partie. Notes et Memoires.
1890.
Y. Wada. Activity aismique recente du Japon, 828. — G. Cotteau.
Note sur le genre Echinolampas, 887.— P. de Loriol. Note sur les
Echinodennes Jurassiques du Portugal, 841. — A. Caraven-Cachin. De
Vage des Conglomerate tertiaires du Tarn et de l'Aude, 344. — A. Caraven-
Cacbin. Description des Argiles RutilantesBartoniennes du Tarn, 347. —
Nicolas. Faune malacolojrique du Danien (Saint-Remy et Lee Baux\
351. — Collot. Coup d'oeil general sur la geologic des Bouches-du
Rh6ne et de la partie contigue du Var, 368.— -E. t. flonnorat-Bastide.
Sur une forme nouvelle ou peu connue de c£phalopodes du crgtare*
inferieur des Basses-Alpes, 867. — Mme. et E. F. Honnorat-Bastide. Sur
les couches indecises du Lias et du bajocien a Digue, 369. — E. Riviere.
La grotte de la Coquille, dite de Minerve, 876. — E. Riviere. Gisements
?uatern aires d'Eragny et de Cergy (Seine-et-Oise), 880. — A. Donnezan.
lecouvertes de fossiles dans le pliocene de Perpignan, 888. — Le Verrier.
Roches eruptives et terrains anciens de la Corse, 388.— E. Ficheur. Sur
la constitution ffeologique du Djebel Chenoua (Alger), 897.— F. Reg-
nault. 1° Fouilles dans le terrain miocene moven de Saint-Gaudens
(Haute Garonne), 2° Fouilles dans les grottes de Gargas et de Malarnaud,
408. — C. BroDgniart. Insectes fossiles du terrain bouiller pourvus de six
ailes, 497.
Digitized by Google
Vol. 50.]
APDITI0X8 TO THE LIBRARY.
207
Paris. Association Franchise pour Tavancement des Sciences.
Compte- Rendu de la 20DW Session. Marseille, 1891. 1" Partie.
Documents Officiels et Proces-verbaux. 1891. Purchased.
M . Boule. Les Grands Animaux Fossiles de l'Amenque, 18.
. . . 2* Partie. Notes et Extraits.
1892.
A. Fournier. Monographies jr6ologiquea des communes du departement
des Deux-Sevres, 370. — E. Riviere. Nouvelle station quaternaire sur les
bords de la Verere. L'abri sous roche de Pageyral, 372. — Matheron.
Sur les series cretacees d'eau douce et d'eau saumatre du midi de la
France, 378. — Matheron. Sur les animaux verte'brea dans les couches
d'eau douce cr£tacees du midi de la France, 382. — P. Pallarv. Lef« faunes
malacologiques pliocene et quaternaire des environs d'Oran, 383. — J.
Leotard. La diminution du relief terrestre et l'accroissement de la
surface continental, 387. — G. Cotteau. Note sur le groupe des clvpeas-
troi'des, 390. — E. Riviere. Nouvelles recherches dans l'Hdrault, &96. —
Mdlle. B. Sinard. Sur la presence du pentacrinus dans le miocene des
Angles (Gard ), 402. — Viguier. Pliocene des environs de Montpellier, 405.
— L. Fournier. Allure geu6rale des niouvements oroge"niques dans les
environs de Marseille, 410. — E. Riviere. Decouverte d'ossements quater-
n aires dans une sabliere de Draveil, 422. — Nicolas. Insectes fossiles
d'Aix (Provence), 425. — A. Caraven-Cachin. Nouvelles recherches sur
les mines et les mineurs gaulois dans le Tarn, 439. — Nicolas. £tude
paleontologique compl£mentaire sur la faune malacologique du danien
des environs de Saint-Remy et les Baux (Provence), 448. — S. Julia.
Sur les calcaires cre"tac68 de la Bedoule, 457.— G. Chauvet. Sur la classi-
fication des temps quaternaires dans la Charente, 613. — Fauvelle. Quelle
est la valeur aes objets de l'industrie humaine comnie elements de
classification des terrains quaternaires a des epoques prehistoriques, 618.
. - Compte-rendu de la 21e Session. Pau, 1892.
1' Partie. Documents Officiels et Proces-verbaux. 1892.
Purchased.
Chaper. Les Mines de diamant de 1'Afriaue Australe, 6. — A. de
I^pparent. L'origine de la houille, 94. — E. Thutat. Les Pyrenees,
. . . . 2* Partie. Notes et Extraits.
1892.
G. Cotteau. La famille des cidaridees k l'epoque eocene, 843. — E.
Riviere. Sur Tage des squelettes humains des grottes des Baoxust-Rovstf,
en Italie, dites grottes de Menton, 347. — E. Belloc. Etude sur l'origine,
la formation et le corableraent des lacs dans les Pyrenees, 358. — E. Riviere.
Determination par l'analyse chimique de la contemporaneity ou de la
non-contemporaneite des ossements humains et des ossements d'animaux
trouves dans un mdme gisement, 377. — Reyt et Dubalen. Sur la pro-
tuberance cretacee de Saint-Sever, 382. — J. Roussel. Sur le primaire
de Campagna-de-Sault, 388. — M. Gourdon. Le Musee pyrentfen de
Bagneres-de-Luchon, 390. — A. Bigot. Sur les trigonies jurassiques de
Norman die, 392.
. Bibliotheque de Tf)cole des Hautes fltudca. Section des
Sciences Naturcllcs. Tome xxxvii. 1890. Purchased.
II. Filhol. Etudes sur les mam mi feres fossiles de Sansan, 1.
. Club Alpin Francais. Annuaire. l'-16me Annees. 1874—
1889. 1876-1890." Purchased.
208
ADDITIONS TO THE LIBRARY.
[Nov.
Paris. Depot <U la Marine. Ann ales Hydrographiques, Serie 2*.
1" et 2" volumes de 1893. 3893.
. Journal de Conchyliologie. Vol. xli. Nos. 1-3. IS 93.
Purchased.
. E. Meyer-Eymar. Description de Coquilles fossil** des terrains
infSrieurs, 51.
. Museum dUistoire Naturelle. Nouvelles Archives. Serie 3.
Tome v. 1893.
. . Centen aire de la Fondation du Museum d'Histoire
Naturelle. 10 Juin, 1793-10 Juin, 1893. Volume Com-
memoratif publid par les Prof esseurs du Museum. 1 893.
A. Gaudry. L'Elephant de Durfort, 325. — E. Bureau. Les collec-
tions de botanique fossile du Museum d'histoire naturelle, 349. — Stanislas
Meunier. Notice historique sur la collection de meteorites du Museum
d'hiatoire naturelle, 399. — A. Lacroix. Apercu des developpementa de
la mineralogie pendant le siecle qui vient de s'ecouler et contribution des
Prolesseurs du Museum a ce progres, 449.
. Revue Scientifiquo. Tome lii. 1893.
H. Moissan. Le Diamant, 193. — II. de Varigny. Le grand recif-barriere
d'Australie, 715.
. . Serie 4. Tome i. 1894.
M. Baudouin. Le Yellowstone National Park, 235, 272.— D. Bellet.
L'industrie eoufriere en Sicile, 432. — M. Boule. Conference de Paleon-
tologie. Cours Speciaux des Voyage urs, 737. — Stanislas Meunisr. Les
Tremblements de terre, a propos des recentes catastrophes de la Grece
et du Venezuela, 760.
. Societe Francaise de Mineralogie. Bulletin. Tome xr.
Nos. 5-9. 1892.
A. Michel-Levy. Sur un nouveau gisement d'Andalousite dans les
schistes carboniferes du Beaujolais, 121. — C. Friedel. Sur des cristaux
de soufre contenus dans une pyrite epigene, 123. — A. Damour. Sur
l'emploi des iodures alcalins dans ^'analyse de quelques matieres mineralea,
124. — E. Jannettaz. Note sur le grenat pyrtnelte, 127. — K Jannettaz.
Note sur le calcaire noir renferniant les 6meraudes de Muso (Nouvelle-
Grenade), 131. — E. Jannettaz. Note sur la propagation de la chaleur
dans les corps cristallises, 133. — L. Bombicci. Keponse a M. Georges
Friedel, 144. — A. Michel-L6vy et Munier-Ch almas. Memoirs sur diverges
formes affectees par le reseau elementaire du quartz, 159. — A. Duboin.
Reproduction de la leucite, de la cryolithe potas^ique et de la n^pheline
potassique, 191. — L. Bourgeois. Reproductions minerales, 194. — L.
Michel Sur quelques mine'raux provenant des environs de Thiviers
(Dordogne), 196. — F. Fouqu£. Sur un mica fonce* a axes ecartes du
Mont^Dore, 196. — E. Porcher. Sur l'epidote, 197.— H. Dufet Notices
cristallographiques, 206. F. Gonnard. Note crystallographique sur la
m6sotype du Puy-de-Dome, 221.— F. Gonnard. Sur l'association de la
fibrolfte et de l'andalousite dans les gneiss de la Haute-Loira, 228.—
F. Gonnard. Sur un nouveau gisement de duniortiente dans le Rhone,
230. — F. Gonnard. Sur la zeolite du domaine de Prat, a Gergovia,
231. — F. Gonnard. Sur l'existence de ranalcime dans le porphyre
dioritique d'Agay ( Var), 231— F. Gonnard. Sur la pyroxenite de Duerne
(Rhone), 232.— E. Jannettaz. Sur un diamant a eclat d'anrent natif,
237. — E. Porcher. Comptes-rendus de mineral ogue, 245. — L. Michel.
Sur la reproduction du grenat nuSlanite et du splume, 254. — C. Friedel.
Sur une pierre de fronde caoaque, en peridot, 256.— C. Friedel. Sur
1 existence du diamant dans le for mtHeorique de Canon Diablo, 258.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY*.
209
Paris. Society Franchise de Mineralogio. Bulletin. Tome xvi.
Xos. 3-8. 1893.
L. Michel. Sur la reproduction du rutile, 37. — L. Michel. Sur une
nouvelle eaj.ece minerale de Bamle, Norvege, 38.— F. Gonnard. Addi-
tion aux mme'raux de la mine du cap Garonne, Var, 40. — F. Gonnard.
Observations a propos d'une note de M. Alfred Lacroix, sur des roches
basiques a nSphtSline du plateau central de la France, 42. — E. Porcher.
Compte-rendu des publications etrangeres, 44. — F. Gonnard. Note
sur let zeolites des basaltes de Coirons, 53. — A. Damour. Nouveaux
essais sur la chloromelanite, 57. — F. Gonnard et A. Oifret. Note cris-
tallographique sur l'axinite de l'Oisans, 75. — A. Gorgeu. Sur lea oxydes
de manganese naturels (nolianites et pyrolusites), 96. — E. Porcher.
Compte-rendu des publications 6tranjferes, 104. — A do Gramont. Sur
les anomalies optiques de la wulftmite, 127. — II. Backstroni. Sur la
reproduction artilicielle de Tajgyrine, 130. — A Gorgeu. Sur les oxydes
de mangane.se naturels, 3e partie, 133. — II. Dufet. Sur les indices de
refraction du spath d'Islande, 149. — G. Wyroubolf. Quelques mots a
propos d'une note de M. G. Woulf, 179. — E. Mallard. Sur la bolelte, la
cumeng^ite et la percylite, 184. — L. Michel Sur une me'lanUSrie
zincifere du Laurium, en Grece, 204. — J. A. da Costa-Sena. Note sur
un gisement d'actinolite aux environs d'Ouro-Proto, a Minas-Geraes
(Br6sil), 206. — F. Gonnard. Notes pour la niineralogie du Plateau
central (France), 208. — L. Duparc et L Mrazec. Note sur la serpentine
de la vallee de Binnen ( Valais), 210. — A. Des Cloizeaux. Nouvelle Note
sur les proprietes crystallographiques et optiques de la p«Srowakite, 218. —
A. Lacroix. Sur deux giaenients de pe>owskite, 227. — A de Gramont.
Compte-rendu des Publications 6trangeres, 231.
. . . Tome xvii Nos. 1-5. 1894.
C. Friedal. Sur la boleite artilicielle, 6 — A. Gorgeu. Sur la pro-
duction artilicielle du gypee, 9. — L Gentil. Sur un cisement d'apo-
phyllite des environs de Collo, 11. — F. Gonnard. Sur l'existence d<> la
gisinondine dans les geodes du basalte de Chabane, pres de Saint-Agreve,
28. — A. Des Cloizeaux et A Lacroix. Phenacite de Saint-Christophe-
en-Oisans, 33. — A. Lacroix. Note pre'liminaire sur les mine>aux des
mines de la valine du Diahot (Nouvelle-Cale"donie), 49. — P. Gaubert.
Comptes-rendus des publications (Strangeres, 57, 98. — L. Bourgeois. Note
rectincative sur la reproduction par voie humide des carbonates cristal-
lises, 79. — L. Gentil. Sur l'existence de la hornblende dans les tufs
yolcaniques du Monte Vulture (basilicate), 81. — L. Gentil. Sur un
giseinent de datolite en Alg^rie, 85. — L. Gentil. Sur la niicrostructure
ae la nielilite, 103. — A. Lacroix. Epidote de Madagascar, 119. — A.
Lacroix. Note additionelle sur la pyroiuorphite de la Xouvelle-Caleclonie,
120. — P. Gaubert. Utilisation du polychroisme produit artificiellement
pour l'6tude des anomalies optiques dans les substances pseudocubiques,
121. — E. Porcher et P. Gaubert Comptes-rendus des publications
e'trangeres, 124.
. Societe Gc'ologique de France. Bulletin. Ser. 3. Tome xx.
1892. No. 6-8. 1893.
Comptes-rendus sommaires de* Siances.
C. Deperet. Note sur la classification et le parallelisme du Systeme
Miocene, clxv. — Munier-Chalmas. £tude pre'liminaire des terrains
jurassiques de Normandie, clxi. — Munier-Chalmas. Sur la possibility
d'admettre un dimorphisme sexuel chez les Amnionitides, clxx. — E. Haug.
Sur l'e'tage Aalenien, clxxiv. — W. Kilian et E. Haug. Sur la constitution
I
210 ADDITIONS TO THE LIBBABT. [XoV. 1 894,
peolojrique de lft vnllee de TUbave (Basses- Alpes), clxxviii. — P. Lory,
femissions {rranulitiques dans le Massif du Pelvoux, clxxx. — E. Haug.
Sur In continuation vers le sud des plis de la Dent du Midi, dxxxiv.—
A. Toucas. Sur le Senonien des Corbieres, cxc.
Notes et Mtmoire*.
C. Gorceix. Notes sur la Geologic des environs de Bayonne, 337.—
P. W. Stuart-Menteath. Sur l'age du granite des Pyrenees occidental**,
.34 5. — E. Fallot. Quelques observations sur le Crtftace' superieur da:.?
Tint^rieur du bassin de l'Aquitaine et ses relations avec les terrains ter-
tiaires, 860. — P. \V. Stuart-Menteath. Sur la geologrie des envirow
d'Eaux-Bonnes, 371. — M. Mieg, Bleicher, et P. Fliche. Contribution &
l'&ude des terrains tertiaires d'Alsace, 375. — E. Lippman et G. Dollfus.
Un forage a Dives (Calvados), 386.— E. Ficheur. Sur les terrains
cretares du massif du Bou-Thaleb (Constantine), 393. — H. F. Oebora.
Sur la decouverte du PaUzonicti* en Amerique, 434. — E. Belloc. Sur 2e
comblement des lacs pyre*n£ens, 437. — J. VVelscb. Sur les plissementa
des couches s«5dimentaires dans les environs de Poitiers, 440. — L. Caret.
Reunion extraordinaire dans les Corbieres et les parties adjacentes de#
Pyrenees, Septembre 1892, 404-635. — L. Carez. Liste des principalei
publications geologiques, 464. — A. De Grossouvre. Cretace- de la region
sous-pyr6neenne, 467. — P. Ziircher. Existence d'une masse de recourre-
ment dans les environs de Toulon, 510. — J. Roussel. Note sur le
Primaire de Campagna-de-Sault, 536.
Paris. Societe* Geologique de France. Bulletin. Ser. 3. Tome
nl 1893. Nos. 1-5. 1893-94.
Notes et MSmoires.
C. Meyer-Eymar. Le Ligurien et le Ton^rien en Egypte, 7. — P. Chofiat.
Coup d'ceil sur les eaux therniales des regions mesozoiques du Portugal,
44. — P. Ziircher. Note sur les phenomenes de recouvrement des environs
de Toulon, 65. — M. Hovelacque. Recherches sur le Lepidodendron selapi'
noides, Sternb., 78. — A. Peron. Sur le Tertiaire supe'rieur de l'Alge'rie,
84. — A. Michel-Levy. Allocution presidentielle, 93. — M. Chaper. Note
sur un gite cuivreux d'origine volcanique du Caucase meridional, 101.—
G. Baron. Notice geologique sur les environs de Menton, 110.— C.
Schluniberger. Note sur les genres Trillina et Linderina, 118. — Tennier.
Sur le Permien du massif de la Vanoise, 124.— Tardy. Sur le Quater-
naire du Mas d'Azil, 134.— C. Sarasin. fetude sur les 'Oppelia du groups
du Nisvs et les Sonneratia du groups du Bicurvatus et du Jtaresukatw^
149. — F. Sacco. Le genre Bathysiphon a l'etat fossile, 165. — C. Deperet.
Sur la classification et le parallelisme du systems mioc&ne, 170.—
Bourgeat. Quelques mots sur l'Oxfordien et le Corallien des bords de Is
Serre, 267. — P. Tennier et W. Kilian. Sur un gisement d'Ammonites
dans le Lias calcaire de l'Oisans, 273. — A. de Grossouvre. Sur la geo-
logie des environs de Bugarach et la Craie des Corbieres, 278. — Boistel.
La Faune de Pikermi a Amberieu (Ain), 996.— P. W. Stuart-Menteath.
Sur le gisement et la signification des fossiles albiens des Pyrenees occi-
den tales, 305. — P. G. de Rouville. Note sur le Cambrien de l'Herault
(Cambrian anglais), 325. — J. Bergeron. Notes paleontologiques : Cru*-
taces, 333. — V. Leinoine. Etude sur les os du pied des Mammiferes de Is
fnune cernaysienne et sur quelques pieces osseuses nouvelles de ret
horizon paltantologique, 353. — D. Sidorenko. Les formations mio-
plioceniques en Russie, 369. — C. Gorceix. Note sur le bassin salifere de
Bayonne et de Briscons, 376. — Jousseaume. Examen d'une serie de
foseiks provenant de Tisthme do Corinthe, 394.— S. Bertolio. Note sur
que'ques roches des collines euganeennes, 406.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIB BABY* 2 1 1
Paris. Society Geologique de France. Bulletin. Ser. 3. Tomo
xxii. 1894. No. 1. 1894.
Rapelin. Sur la constitution ge*ologique du massif des Soumata et
d'Hammam Rirha (Algene), 7. — A. Bnve. Terrains miocenes de la
region de Carnot (Afy^rie), 17. — 0. de SteTani. Decouverte d'une faune
paleozoique a Hie d'Elhe, 30. — P. Marty. Le Thalweg geologique de la
moyenne vallee de la Cere, 84.— P. Zurcher. Note sur le mode de forma*
tion dea plis de l'ecorce terrestre, 64.
. . Memoires. Paleontologie. Tome iii. Fasc. 4. 1893.
H. Douville*. £tudes sur les Rudistes. No. 6.
. . . . Tome iv. Fasc. 1. 1893.
C. Dep£ret et A. Donnezan. Les animaux pliocenes du Roussillon.
No. 3. — R. Zeiller. Etude sur la constitution de l'appareil fructificateur
des Splienophyllitm, No. 11.
Penzance. Royal Geological Society of Cornwall. Transactions.
VoLxi. Part 8. 1894.
Howard Fox. Anniversary Address, 495. — J. D. Enys. On the
Action of Wind and Sand in cutting Stone, 533. — A. Somervail. The
Origin and Relations of the Lizard Rocks, 536. — F. J. Stephens. On
some remarkable Contortions of Rocks at Rosemullion Head, 544. — •
F. J. Stephens. On some Manilla Andesites, 651. — J. H. Collins.
Illustrations of Cornish Fossils. 552.— J. J. H. Teall. On Greenstones
associated with Radiolarian Cherts, 660.
Philadelphia. Academy of Natural Sciences. Journal. Series 2.
Vol. x. Part 1. 1894.
. . . Proceedings. 1893. Parts 1-3. 1893.
E. D. Cope. A new extinct Species of Cyprinidn, 19. — E. Goldsmith.
Notes on some Minerals and Rocks, 174. — A. Meyer. Notes on the
Occurrence of Quartz and other Minerals in the Chemung Measures, near
the line of Lycoming and Tioga Counties, Pennsylvania, 194. — A. Meyer.
Pyrophyllite Slates in Northern Pennsylvania, 197. — E. D. Cope. De-
scription of a Lower Jaw of Tetrabelodon Shepardi, 202. — L. Woolman.
Cretaceous Ammonites and other Fossils near Moorestown, N.J., 219. —
R. S. Tarr. Notes on the Physical Geography of Texas, 313. — E. Gold-
smith. A Tempered Steel Meteorite, 373.— E. D. Cope. Fossil Fishes
from British Columbia, 401.
. American Philosophical Society. Proceedings. Vol. xxxi.
Nos. 140-142. 1893.
B. S. Lyman. The Great Mesozoic Fault in New Jersey, 314.— E. D.
Cope. On the Genus Tomwpsis, 317.
— . . . Vol. xxxiii. No. 144. 1894.
B. Smith Lyman. Age of the Newark Brownstone, 6. — E. D. Cope*
On the Structure of the Skull in the Plesiosaurian Reptilia, and Two
New Species from the Upper Cretaceous, 109.
. . Transactions, N.S., Vol. xvii. Part 3. 1893.
. . . VoLxviii. Parti. 1893.
Digitized by Google
212
ADDITIONS TO THE LIBBABT.
[Nov. 1894,
Pisa. Society To scan a di Scienze Naturali. Atti. Memorie.
Vol. vi. fasc. 3. 1892.
. . . . Vol. xii. 1893.
L. Busatti. Anpunti etratigrafici e paleontologici sopra Vallebbidia,
commune di Fauglia in provincia di Pisa, 75. — A. d'Achiardi. Le roccv
del verrucano nelle valli d'Asciano e d'Agnano nei Monti Pisani, 139.—
L. Busatti. I portidi della miniera di Tuvioia nel Sarrabus, Sardegna,
162. — A. Fucini. Alcuni fossili del Lias inferiore delle Alpi Apuane e
dell' Appenino di Lunigiana, 293.
. . . . Vol. xiii. 1894.
L. Busatti. Contribuzioni chimico-mineralogiche e petrogTaficbe, 3.
— B Greco. II Lias inferiore nel Circondario di Rossano Calabro, 55.—
O. Trabucco. Sulla vera po*izione dei terreni terziari del bacino Pie-
montese, Parte 1*, 181.— -G. d'Acbiardi. Le Tormaline del granito
Elbano, 229.
. . . Processi Verbali. Vol. ix. pp. 1-62. 1894.
P. E. Vinassa <te Regny. Un' escursione nelle Alpi venete, 33.—
M. Canavari. Ancora su l'eocenicita della parte superior© della Scag'is
nell' Appenino centrale, 43. — M. Canavari. Sul preteso Dogger infe-
riore di Monte Gemmo presso Camerino, 44. — A. Fucini. L' Unio sinuatw,
Larak., nelle antiche alluvioni del Tevere presso Citta di Castelio
(Umbria), 69.
Plymouth. Devonshire Association for the Advancement of Science,
Literature, and Art. Report and Transactions. Vol. xxv.
1893.
. Plymouth Institution. Annual Report and Transactions.
Vol. xi. Part 3. 1*92-93. 1893.
Port-of-Spain. Victoria Institute of Trinidad. Proceedings. PartL
1894.
Prague. See Books : Bohemia.
Ramsey, Isle of Man (and Douglas). Isle of Man Natural
History and Antiquarian Society. * Vannin Lioar ' : afterwards
k Yn Lioar Manninagh.' Vol. i. Nos. 1-11. 1889-92.
W. Boyd Dawkins. On the Geology of the Isle of Man: Part I. On
the Conglomerates of the South of the Island, 10. — A. Haviland. The
Aspects of the " Craigs " of the Manx Mountains in relation to th*
Glaciation of the Island, (77), (81).— P. M. C. Kermonde. Fossil Stella
from the Boulder Clay and Sand, North Ramsey, 96. — P. M. C. Ker-
monde. Flints from the Brooghs, North Ramsey, 131. — J. W. Brown.
Flints from the West Craig, Andreas, 174.— S. Gasking. On the Geolojry
of the South of the Island, (119).— S. Gasking. The so-called Old Red
Sandstone of the Isle of Man, (136). — S. N. Harrison. Boulders around
the Manghold Coast, 208. — B. Hobson. On the Igneous Rocks of the
South of the Isle of Man, 337.
[Numbers of pages in ( ) refer to " back Transactions
of the Society.*']
1
Digitized by Googl
Vol. 50.]
ADDITIONS TO THE LIBRARY.
Beading. Reading Literary and Scientific Society. Report and
Proceedings, 1890. 1890.
J. H. Blake. Geological Excursion to Norcot Kiln nnd Tilehurst, 23.
— J. H. Blake. Geological Excursion to Nettlebed, 23. — O. A. Shrub-
sole. Geological Excursion to Twyford and Kuscombe, 25. — J. II. Blake.
Geological Excursion to Henley, 25.
. , 1891. 1891.
O. A. Shrubsole. Geological Excursion to Moulsford, 20. — J. II. Blake.
Geological Excursion to Wargrave and Bowsey Hill, 28.
. , 1892. 1892.
O. A. Shrubsole. The Story of the Great Ice Age, 20.— O. A. Shrub-
sole. Geological Excursion to " Hungry Hill.'' Aldershot, 25. — O. A.
Shrubsole. Geological Excursion to Streatley, 20.
. , 1893. 1893.
J. E. Marr. " Greenland's Icy Mountains," 23. — J. H. Blake. Geolo-
gical Excursion to Medmenbam, 37.
Rio de Janeiro. Museu National do Rio de Janeiro. Archivos.
Vol. viii. 1892.
Rochester, N.Y. Geological Society of America. Bulletin. Vol. iv.
1893.
C. H. Hitchcock. Studies of the Connecticut Valley Glacier, 3. — ■
James Hall. The Oneonta Sandstone and its Relations to the Portage,
Chemung, and Catskill Groups, 8. — Warren Upham. Conditions of
Accumulation of Drumlins, 9. — A. S. Tiffany. Ancient Waterways, 10.
— G. F. Becker. Finite Homogeneous Strain, Flow, and Rupture of
Rocks, 13. — C. S. Prosser. The Thickness of the Devonian and Silurian
Rocks of Central New York, 91. — D. White. A new Tteniopteroid
Fern and its Allies, 119. — L. E. Hicks. Some Elements ot Land
Sculpture, 133. — C. L. Whittle. Some Dynamic and Metasomatic
Phenomena in a Metamorphic Conglomerate in the Green Mountains,
147. — H. Hobbs. Phases in the Metamorphism of the Schists of
Southern Berkshire, 107. — Warren Upham. Comparison of Pleistocene
and present Ice-sheets, 191. — J. S. Diller. Cretaceous and early Tertiary
of Northern California and Oregon, 205, — H. P. II. Brumell. On the
Geology of Natural Gas and Petroleum in South-western Oregon, 225. —
H. P. ft. Brumell. Notes on the Occurrence of Petroleum in Gasped,
Quebec, 241. — T. W. Stanton. The Faunas of the Shasta and Clnco
Formations, 245. — W. Lindgren. Two Neocene Rivers of California,
257. — C. R. Keyes. Epidote as a primary Component of Eruptive Rocks,
305. — A. E. Barlow. Relations of the "Laurentian and Huronian Rocks
north of Lake Huron, 313. — W. II. C. Smith. The Archaean Rocks
west of Lake Superior, 333. — R. W. Ells. The Laurentian of the
Ottawa District, 349. — R. Chalmers. Height of the Bay of Fundv coast
in the Glacial Period relative to Sea-level, as evidenced by Marine "Fossils
in the Bculder-clay at SaintJohn, New Brunswick, 361. — H. P. II.
Brumell. On the Geology of Natural Gas and Petroleum in South-
western Ontario. 408. — J. W. Dawson. Note on Fossil Sponges from
the Quebec Group (Lower Cambro-Silurian) at Little Metis, Canada,
409.— W.J. McGee. A Fossil Earthquake. 411.— A. P. Low. Notes
on the Glacial Geology of Western Labrador and Northern Quebec, 419.
— G. F. Wright. The supposed post-Glacial Outlet of the Great Lakes
214
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
through Lake Nipissing and the Mattawa River, 423.— G. M. Daw*on.
Notes on the Geology of Middleton Island, Alaska, 427. — C. R. \*n
Hise. The Huronian Volcanica south of Lake Superior, 436. — N. H,
Darton. On two Overthrusta in Eastern New York, 436.
Rochester, N.Y. Rochester Academy of Science. Proceeding.
VoL ii. Brochure 2. 1893.
E. \V. Dafert and 0. A. Derhy. The Separation of Minerals of Hi*rh
Specific Gravity, 122. — H. I/. Preston. Preliminary Note on a new
Meteorite from Kenton County, Kentucky, 151. — H. A. Ward. Pr*?-
liminary Notice of a new Meteorite from Japan, 171.
Rome. R. Accademia dei Lincei. Atti. Serie 5. ReodiconrL
1893. Vol. ii. l°Semestre. Fasc. 10-12. 1893.
G. Agamennone. I terremoti e le perturbazioni magnetiche, 479.
. . . . 1893. Vol. ii. 2° Semestre.
Fasc. 1-12. 1893.
F. Bassani. U pliocene alia base dei Monti Cornicolani e Lucani, 58.—
F. Bassani. La fauna hentho-nektonica della pietra leccese (miocene
medio), 91. — G. de Lorenzo. La fauna bentho-nektonica della pietra
leccese (miocene medio), 119.— G. de Lorenzo. II postpliocene morenico
nel gruppo montuoso del Sirino in Basilicata, 317.— G. Agamennone,
Velocita di propagazione delle principali scosse di terremoto di Zante nel
recente periodo sismico del 1893, 393.
. . . . 1894. Vol.iii. 1° Semestre.
Fasc. 1-11. 1894.
D. Lovipato. Sulla Senarmontite di Nieddoris in Sardegna e sai
minerali che l'accompagnano in quella miniera, 82. — E. Clerici. Notixie
rntorno ai tufi vulcanici della via Flaminia dalla valle del Vescovo a
Prima Parta, 89. — D. Lovisato. H Devoniano nel Gerrei (Sardegnrt), 131,
G. do Lorenzo. Sulla geologia dei dintorni di La^onegro, 135, 309, 351.
D. Lovisato. Avanzidi Squilla nel miocene medio di Sardegna, 205. —
A. Ricco. Velocita di propagazione delle principali scosse del terremoto
di Zante a Catania, 246.— G. Boeris. Sopra la Calcocite di Montecatini,
304.— A. Cancani. Sopra i microfoni nella sismologia, 328. — E. Clerici.
Considerazioni sopra i tufi vulcanici al nord di Roma, fra il fosso delU
Crescenza e quello della Torraccia, 343.— G. de Agostini e O. Marinelli.
La comunicazione sotterranea fra il canale d'Arni e la Pollaccia nelle
Alpi Apuane, 354. — G. Agamennone. Alcune considerazioni sulla
velocita di propagazione delle principali scosse del terremoto di Zante
nel 1898, 383.— G. Agamennone. Velocita di propagazione super-
ficiale dei due terremoti della Grecia del 19 e 20 settembre 1867,
889, 443.— A. Cancani. Sopra alcune notevoli roccie magnetiche trovate
nell'e vicinanze di Rocca di Papa, 890.— E. Clerici. Sulla origine dei
tufi vulcanici al nord di Roma, 407. — G. Agamennone. I terremoti di
lontana provenienza registrati al Collegio Romano, 494.
R. Comitate Geologico dltalia. Bollettino. 1892. VoLxxiii.
1892.
L. Mazzuoli. Nuove osservazioni sulle formazioni ofiolitiche della
Riviera di Levante in Liguria, 12.— B. Lotti. Considerazioni sintelicbe
sulla orografia e sulla geologia della catena metallifera in Toecana, 55. —
C. Viola. Nota prelinnnare sulla regione dei gabbri e delle serpentina
Digitized by Google
Vol. 50.J
ADD1TION8 TO THE LIBRARY.
nell' alta valle del Sinni in Basilicata, 105. — G. Di Stefano e C. Viola.
L' eta dei tufi calcarei di Matera e di Gravina e il sottopiano " Materino ,r
M.£.,l2o. — D. Zaccagna. Riassunto di osservazioni geologiche fatte
sul versante occidentals delle Alpi Graie, 175. — C. Viola. Communi-
cazione prelirainare sopra un terreno cristallino in Basilicata, 244. — D.
Zaccagua. Riassunto di osservazioni geologiche fatte sul versaute occi-
dentale delle Alpi Graie, 311.
Rome. Societa Geologica Italiana. Bollettino. Vol. xi. 1892.
Fasc. 2. 1893.
E. Clerici. L'Ursus spelaeus nei dintorni di Roma, 105. — B. Cord
Osservazioni stratigTafiche paleontologiche sulla regione compresa fra i
due rami del lago di Como e limitata a sud dai laghi della Brianza, 111.
— G. Trabucco. Risposta ad alcune osservazioni alia Nota u L'isola di
Lampedusa," studio geo-paleontologico, 209. — A. Neviani. Sulla Ophio-
glypna (Acroura) pranulata, Benecke sp., del Muschelkalk di Recoaro,
214. — B. Oorti. Foraminiferi e diatomee fossili delle sabbie gialle plio-
ceniche della Folia d'Induno, 223. — G. Di Stefano. Sulla estenzione del
Trias superiore nella provincia di Salerno, 231. — E. Dervieux. Le
FrondicuUirie terziarie del Piemonte, 230. — P. Franco. Studi sull*
idocrasia del Monte Somma. 245.
. . . Vol. xii. 1893. Fasc. 2 & 3. 1893.
A. Neviani. Seconda contribuzione alia conoscenza dei briozoi fossili
Italiani, 109. — E. Clerici. Sopra alcune imprente di foglie nei tufi
granulari di Roma, 137. — L. Botto-Micca. Fossili degli " strati a Lio-
ceras opalinum, Rein., e Ludwigia Murchisonte, Sow.," della Croce di
Valpore (M. Grapa) provincia di Treviso, 143. — G. Bonarelli. Osser-
vazioni sul taorciano e 1' aleniano dell' Appennino centrale, 195. — A.
Issel. Appnnti geologici sui colli di Balaissero (Canavese), 255. — S.
Traverso. Appunti petrogTafici su alcune rocce di Balissero (Piemonte),
281. — G. A. de Amicis. Contribuzione alia conoscenza dei foraminiferi
pliocenici : I foraminiferi del pliocene inferiore di Trinity- Victor (Niz-
zardo), 293. — V. Novarese. Relazione sulT escursione del 18 settembre
rivrea], 530. — G. Tuccimei. Escursione alia Val d' Aosta e ai ghiacciai
del Monte Bianco eseguita li 21 e 22 settembre, 549. — V. Simonelli. Le
sabbie fossilifere di Selenitza in Albania, 552. — A. Verri. Note per la
storia del Vnlcano Laziale (Gruppo dei crateri), 559. — C. De Stefani,
Granulite, granitite in massa ed in filoni e trachite quarzifera eocenica
dell' isola oVElba, 587.
Rugby School Natural History Society. Report for the year 1893.
1894.
St. John, N.B. Natural History Society of New Brunswick.
Bulletin. No. 11. 1893.
G. F. Matthew. The Climate of Acadia in the Earliest Times, 3. —
G. Stead. Notes on the Geography and Natural History of the Tobique,
19. — S. \V. Kain. Sand Cove and Manawagonis, 46.
St. Petersburg. Acadcmie Imperiale des Scienoea. Me'moirea.
Tome xli. No. 5. 1893.
J. V. Rohon. Die obersilurischen Fische von Oesel, ii. Theil, 1.
San Francisco. California Academy of Sciences. Proceedings.
Series 2. Vol. iii. 1890-92. 1893. Purchased.
A. W. Vogdes. Geological Surveys in the State of California, 325.
vol. L. r
2l6 ADDITIONS TO THE LIBRABT. [Nov. 1 894,
San Francisco. California Academy of Sciences. Occasional Papers.
III. 8vo. 1893. Purchased.
. . . IV. A Classed and Annotated Bibliography
of the Palaeozoic Crustacea, 1698-1892 ; to which is added a
Catalogue of North American Species, by A. W. Vogdes. Svo.
1893. Purchased.
Santiago de Chile. Deutscher wissenschaftlicher Yerein. Verband-
lungen. Band ii. Hefte 5 & 6. 1893.
A. Pohlmann. Das Vorkommen und die Bildtmg- des sog. Glocken-
eteins (Magnesit) auf Juan Fernandez, 320. — K. Pbhlniann. Ueber da^
falschhcher Weise Leucit-Lava genannte Qestein des Vulkans von Chil-
ian, 326.
. Socie'te' Scientifique du Chili. Actes. Tome iii. 1893.
Livr. 1-3. 1893.
J. van Holten. Sources de pe*trole en Bolivie lvii.
Mimoires.
A. F. Nojrues. Note sur les fractures des terrains a Lignites du sud
du Chili, 129.— A. F. Nogues. Note sur les gisements de charbon de
Quilacoya, 137 — A. F. Nogues. Note sur un voyage geologique des
Themes de Cauquenes au glacier des Cipres, 148.
. . . Tome IV. 1894. Livr. 1. 1894.
Proces-verbaux.
F. Servat, Sobre la composicion de la olivina de Juan Fernandez,
zlix.
Shanghai. China Branch of the Royal Asiatic Society. Journal.
N.S. Vol. xxv. 1890-91. 1893.
Sherborne [Dorchester]. Dorset Natural History and Antiquarian
Field Club. Proceedings. VoL vi. 1885.
J. C. Mansel-PleydelL Geological Notes on the Isle of Portland, 68.
— J. C. Mansel-PleydelL A Fossil Chelonian Reptile from tho Middle
Purbecks, 66.
■ . . Vol. vii. 1886.
J. C. Mansel-PleydelL On Volcanoes and Earthquakes, 6. — O. H.
West Geology of Bournemouth, 28. — M. G. Stuart. On the Punfield
Beds of Punfield Cove, 43.— J. C. Mansel-Pleydell. On a Tufaceous
Deposit at Blnshenwell, Isle of Purbeck, 109.
. . . VoLviii. 1887.
T. B. Groves. The Ahbotshury Iron Deposits, 64.
. . . Vol. ix. 1888.
J. C. Mansel-PleydelL Fossil Reptiles of Dorset, 1.
. . . VoL x. 1889.
J. C. Mansel-PlevdelL Note on El&phaA meridionals, found at
Dewhsh, 1.— M. G. Stuart. The Ridgway Fault, 65. — J. C. Mansel-
PleydelL Bos pritniffenius, with relation to Paleolithic and Neolithic
•
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
217
Man, 81. — J. C. Mansel-Pleydell. Cimoliosaurus richardsoni, Lydekker
(n. sp.), 171.— T. B. Groves. The Erosion of the Coast near Weymouth
by the Action of the Sea, 180.
Sherborne [Dorchester]. Dorset Natural History and Antiquarian
Field Club. Proceedings. Vol. xii. 1891.
A. M. VVallis. The Portland Stone Quarries, 187.
. . . Vol. xiii. 1892.
J. C. Mansel-Pleydell. Kimineridge Coal-Money and other Manufac-
tured Articles from the Kimmeridge Shale, 178.
Springfield, Illinois. Illinois State Museum of Natural History.
Bulletin. No. 3. 1893. 1894.
S. A. Miller and W. F. Gurley. Description of some New Species
of Invertebrates from the Palaeozoic Rocks of Illinois and Adjacent
States, 1.
Stockholm. Geologiska Forening. Forhandlingar. Band xiv.
Hafto 5-7. 1892.
J. C. Moberg. Om den af Trinucleus coscinorrhinus Ang. karakter-
iserade kalkens geologiska ftlder, 379. — II. Sjogren. Preliminara meddel-
anden frftn de Kaukasiska naftafalten, II., 383. — H. Sjogren. Bidragtill
Sveriges mineralogi, 423. — J. II. L. Vogt. Om verdens nikkelproduktion
og om konkurrance-betingelserne mellem de norske og de udenlandske
nikkelforekomster, 433.— G. Lofstrand. Basiska utabndringar och
crSngformiga bildningar af ^ernmalm i sura uruptiva bergarter inbm
Norbottens lan, 476.— K. J. \. Steenstrup. Endnu et Par Ord om Flyve-
sandets indvirkning paa rullestenes form, 493. — G. C. von Schmalensee.
Om lagerfbljden inom Dalarnes siluromrfiden, 497. — L. J. Igelstrom.
Mineralogiska meddelanden, 504, 583. — G. Andersson. Om slamning af
torf, 506. — G. Andersson. Om de vhixtgeografiska stoden for antagandet
af klimatvaxlingar under kvartartiden, 509. — A. G. Hogbom. Om
miirken efter isdiimda sjoar i Jemtlands fjelltrakter, 561. — V. Madsen.
Om Iiissoa parva Da Costa, og andre postglaciale mollusker pS Aland,
585.
. . . Band xv. Hafte 3-7. 1893-94.
G. de Geer. Om i.*opachyter eller maktighetokurvor, 130. — H. Sjog-
ren. Om vatskeinneslutningar i gips fr&n Sicilien, 130. — H. Sjogren
Ytterligare om Ruotivare jernmalm, 140. — A. G. Kell^ren. Om gran-
gransen i Lule Lappmark, 144. — G. Nordenskiold. Preliminart meddelande
rorande en undersokning af snokristaller, 146. — H. Hedstrdm. Om den
senglaciala marina gransen i Dalarne, 169. — O. Nordenskjold. Om de
poriyriska gfingl)ergarterna i ostra Smftland, 169. — G. Flink. Om nagra
mineral frfin Grbnland, 195. — A. G. Hogbom. Om postarkaiska erup-
tiver inom det svensk-n'nska urberget, 209. — A. G. Hogbom. Om de s. k.
urgraniterna i Upland, 241. — B. Frosterius. Om en diabas i Foglo i den
Slandska skargfirden, 275. — II. Hedstrom. Om hasselns forntida och
nutida utbredning i Sverige, 291. — II. Lundbohm. Om berggrunden i
Vesternorrlands kusttrakter, 321. — G. Ilallberg. Apophvllit frfin Gran-
gesberg, 327. — L. J. Igelstrbm. Mineralogiska meddelanden, xix., 343. —
K. Sernander. Om Litorinatidens klimat ocn vegetation, 345. — G. De Geer.
Om strandliniena forskjutning vid vara insjoar, 378. — O. A. Sjostrbm.
Mineralanalytiskt meddelande, 393. — A. E. Nordenskiold. Om stoflfallen
i Sverige och angransande lander den 3:dje majl892, 417. — G. Norden-
skiold. Spondiosit fran Nordmarken, 4G0. — G. Flink. Tillagg till upp-
2l8 ADDITIONS TO THE LIB BART. [NOT. I SO-f-
eatsen " Om nftgra mineral fr&n Gronland," 471. — J. L. Igelstrom.
Mineralogiska meddelanden, 471. — H. Sjogren. N&gra jemfoivls^r
melland Sveriges och utlandets jernraalrnslager iued hansyn till deras
genesis, 473. — A. Hamberg. Cm en profil frSn akredet i Vferdalen, oil.
—A. G. Nathorst. Om en fossilforande leraflagriug vid Skattmansui
Upland, 539.— P. J. Holmquist. PyTOchlor frSn Alnon, 568.— S. Rud-
beck. Ora en kromhalti^ veauvion frSn Ural, 007. — A. E. Tornebobm.
Oni Falu grufvas geologi, 009.— K. O. Segerberg. Meddelanden itin
Lunds Geologiska Faltklubb, 691.
Stockholm. Geologiska Forcning. Forhandlingar. Band xvi.
Hiifte 1-4. 1894.
H. Munthe. Om biologisk undersokning af leror, o. s. v., 17.— -P.
Dusem Om nordvastra Kamerunomrficlets geologi, 29. — P. J. Holmquist
Knopit, ett perowskit niirstfiende nytt mineral frSn Alnon, 73. — V. Oberg.
Flottholmen i sjiin RalSngen, 96. — H. Backstrom. Tvanne nvupptakta
evenska klotgraniter. 107. — G. Lofstrand. Gl&ngforruiga inalmbildningsir
i Norbotten, 131.— G. Nordenskiold. Kentrolit och melanotekit, 151.—
P. J. Holmquist. Om diabasenpS Ottfjallet i Jemtland, 175. — E. 8red-
mark. Meddelanden om jordstotar i Sverige, 193. — F. de Montessu<de
Ballore. Le monde scandinave sismique, 225. — R. Sieger. Flott-
holmen i sjiin Ral&ngeu och vattenstfindets oscillationer, 231.— J. C.
Moberg. Dictyograptus contra Dictyonema, 236. — H. Hed>trom.
Studier ofver bergarter frSn moriin vid A lsby, 2 17. — J. H. L. Vogt.
lagformigt optnedende jernmalmforekomster af typus Dunderland, Xor-
berg, Griingesberg, Persberg, Arendal, Dannemora, 275. — J. Wallerius.
Geologiska studier i Vestergbtland, 298. — A. Hamberg. Mineralogist
Studien, 307. — G. Lindstrom. Mineralanalvser, 330. — G. Xordenski«>ld.
Om n&gra sallsynta mineral frfin Igaliko i Gronland, 330. — E. Svedmark.
Ytterligare om flottholmen i sjcin IialSngen, 347. — E. Svedmark. MeAfe-
landen om jordstotar i Sverige, 357. — A. G. Nathorst. En vaxtiorande
lera frSn Viborg i Finlann, 361. — A. G. Nathorst. Om albladen i ancv-
lusleran vid Skattmanso, 370.— A. G. Kellgren. En ny konstruktion at
mossborr, 372.
. Kongliga Svenska Vetenskaps Akademi. Handlingar. NX
Bandet xxii. Hiiftet 1 & 2. 1886 och 18S7. 1890.
J. C. Moberg. Om Lias i sydostra SkSne, No. 6. — L. Ilolmstrum.
Om strandlinens forskjutning 8 Sveriges kuster. No. 9.
. . . Bandet xxiii. Hiiftet 1 & 2. 1SSS-18^
1891.
C. W. S. Aurivillius. Der Wal Svendenborgs (Bal&na Sveden-
borffii).—Q. Lindstrom. The Ascoceratidte and tbe Lituitida of the Upper
Silurian formation of Gotland. No. 12.
. . . Bandet xxiv. Hiiftet 1 & 2. 1S90 och
1891. 1891.
A. G. Nathorst. Ueber die Reste eines Brotfiuchtbaums, Artocarjm
JXcksoni, n. sp., aus den cenomanen Kreideablagerungen GruDlands,
No. 1. — C. W. S. Aurivillius. Ueber Symbiose als Grund accessorised
Bildungen bei marinen Gastropodenhausen, No. 9. — H. Conwentt.
Untersuchungen iiber fossile Holzer Schwedens, No. 13.
. . . Bihang till Bandet xiv. 1889.
H. Backstrom. Ueber den Rhombenporphyr aus dem Brumunthale
in Norwegen. Afd. ii. No. 3. — T. Thoroddsen. Vulkaner i det nordost-
Digitized by Googl
Vol. so.]
ADDITIONS TO TIIE LIBRARY.
219
lige Island. Afd. ii. No. 4. —A. Schenk. Fossile Iliilzer aus Ostasien
und .Egypten. Afd. iii. No. 2.
Stockholm. Kongliga Svenska Vetenskaps Akademi. Handlingar.
Bihang till Bandet xv. 1890.
W. 1'etersson. Om naturliga etsfigurer och andra liisningsfenomen p8
beryll frfin Mursinsk. Afd. ii. No. 1. — II. Backstrcini. Kemisk undersoK-
niug af nigra mineral fr&n trakten af Langesund. Afd. ii. No. 3.
. . . . Bandet xvi. 1891.
H. Backstriim. Ueber fremde Gesteinseiuschlusse in einigen skandi-
navischen Piabasen. Afd. ii. No. 1. — M. Weibull. Studier iifver arsenik-
lrisens kristallform och saminansattning, Afd. ii. No. 2. — G. Flink.
Mineralogische Notizen. III. Afd. ii. No. 4. — H. Backstriim. Ueber
angeschwemmte Bimsteine und Schlacken der nordeurojjriischen Kusten.
Afd. ii. No. 5. — G. Holm. Gotland's graptoliter. Afd. iv. No. 7.
. . . Bandet xvii. 1892.
A. E. Nordenskiold. Ytterligare om gadolinitjordens molekylarvigt.
Afd. ii. No. 1. — P. Thoroddsen. Geologiske iajrttagelser paa Snoefellsnes
og i Omecnen af Taxebugten i Island. Afd. ii. No. 2. — G. Nordenskiold.
Kedogoreise for den svenska expeditionen till Spetsborgeo, 1890. Afd. ii.
No. 3. — K. Johansson. Studier iifver enstatit och dess omvandlings-
Srodukter. Afd. ii. No. 4. — A. G. Nathorst. Ueber den ge<renwarti£en
tandpunkt unserer Kenntniss von dem Vorkommen fossiler Glacial-
pflanzen. Afd. iii. No. 5.
. . . Bandet xviii. 1892-1893. 1893.
Afdclning I. (Mathcmatik, Sfc.)
Afdebting II.
H. Munthe. Studier iifver Baltiaka hafvets q uartara historia. I.
Baltiska historia fr&n och med den pra)glaciala till och med den nyare
glaciala epoken, No. 1.
Afdelning III.
G. Andersson. Vaxlpaleontologiska undersiikningar af svenska
torfmossar, Nos. 2 and 8.
Adfelning IV.
C. W. S. Aurivillius. Ueber einige obersilurische Cirripeden aus Got-
land, No. 3.
. . Ofversigt af Fiirhandlingar. 46e ArgSngen.
Ar 1889. 1890.
G. Flink. Mineralogische Notizen, II. 6. — N. V. Ussing. Under-
sogelse af mineraler fra Fiskernais i Griinland, 15.
. . . 47e Argitngen. Ar 1890. 1891.
A. Schenk. Jurassische Hiilzer von Green Harbour auf Spitzbergen,
6. — A. G. Nathorst Om forekomsten af Dictyophyllum NiUsoni Brongn.
ep., i Kinas Kolfiirande bildningar, 409.
. . . 48e ArgSngen. Ar 1891. 1S92.
It. Lundgren. SmSnotiser om de liisa jordlagren, 75.
. . . 49" ArgSngen. Ar 1892. 1893.
A. G. Nathorst. Om nSgra mollusker och ostrakoder frSn quartara
sotvattensaflagringar i Ryssland och Tyskland, 425. — A. G. Nathorst.
Om nfigra till ltiksmuseets vaxlpaleontologiska afdelning inkomna torf-
mossefynd, 429.
220
ADDITION"? TO TILE LIBRARY.
[Nov. 1S94,
Stockholm. Kongliga Svenska Vetenskaps Akademi. Overaigt
af Forbandlingar. 50* Argangen. Ar 1893. 1894.
J. G. Andersson. Ueber das Alter des IsochHina canaUcttlata-Y&xm*,
Vio. — J. G. Andersson. Ueber Blocke a us dem j iingeren Untersilur auf
der Insel Oland vorkommend, 5r?1.
. . Lefnadsteckningar. Band iii. Hafte L 1S91.
Carl von Linnets Brefvexling. 8vo. I880.
Stuttgart. Xcues Jahrbuch fiir Mineralogie, Geologie und Palaon-
toiogie. 1S93. Band ii. Hpfto »2&3. 1S93.
A. I.iebrich. Ueber eine ei«renartige Kalksteinbildung in doleritUcben
Verwitterungsproducten, 75.— F. Toula. Ein A mmonitenfund (AcantAo-
ccras Mantelli, Sow.) im Wienersandstein des Kahlengebirges bei Wien,
79. — H. Potonie". Folliculites Kaltennordheimensi*, Zenker, und Follicu-
lites carina t u* (Xehring), Pot., 8iL — A. W. Stelzner. Ueber Franckeit,
ein ueues Era aus Bolivia, 114. — A. Frenzel. Ueber den Kylindrit, 125.
— F. von Sandberger. Ueber einijre Conchy lien aus pleistocanen Kalktufien
Schwedens, 129.— Q. Biihm. I eber Cornucaprina, 122. — J. W. Retgers.
Der Phosphor als stark lichtbrechendes Medium zu petrographiaehen
Zwecken, 130. — E. Stolley. Ueber silurische Siphoneen, 135. — G. Bod-
lander. Versucbe iiber iSuspensionen, I., 147. — F. Toula, Die Kalke
der Grebenze im Westen des Neumarkter Sattels in Steiermark, 100. —
B. Hecht. Bemerkung zu dem Satze, nach welchem Svmmetrieaxea
immer mogliche Krystallkanten sein sollen, 17-'l — H. A. Miers. St ango-
lith von Cornwall, 174. — A. Wichmann. Ueber Glaukophan-Epidot-
Glimmerschiefer von Celebes, 17ft.
. . Jahrgang 1894. Band L Hefte 1=3, 1894.
F. Rinne. Vergleich von Metallen mit ihren Oxyden, Sulfiden, Hy-
droxyden und Halogenverbindungen beziiglich der Krystallfomi, L —
E. von Fedorow. Minimumproblem in der Lehre von Symmetrie, 5G. —
G. A. F. Molengraaff. Cordierit in einem Eruptivgestein aus Siidafrika,
Z8. — B. Minnigerode. Ueber die Symmetrieverhaltnisse der Krystalle,
82. — A. Weisbach. Ueber den Argyrodit, 88. — K. Dalmer. Ueber das
Alter der Granit- und Porphyrgesteine der Insel Elba, OH — E. Stolley.
Ueber die Verbreitung Algen-funrender Silurgeschiebe, 108. — T. Fuchs.
Geologische Studien in den j iingeren Tertiarbildungen Rumanieu?, ILL
— H. Traube. Ueber die Krystallform einiger Lithiumsalze, 171. —
• H. Traube. Ueber die Isomorphic von Sulfaten, Selenaten, Chroniaten,
Molybdaten und Wolframaten, 185. — F. von Sandberger. Zinckenit von
Cinque valle im Val Sugana, Siidtvrol, 19fi. — E. Hess. Bemerkungen
zu L. v. Fedorow's Elementen der destaltenlehre, 197. — E. von Fedorow.
Noch ein Wort iiber den Satz, nach welchem Symmetrieaxen immer
mogliche Krystallkanten eein sollen, 199. — J. Bohm. Ueber Capulus
myoma, Sow. sp„ 200. — F. von Sandberger. Zanclodon im obersten Reuper
Untertrankens, 203. — R. Brauns. Betrachtungen iiber die chemische
Zusammensetzung der Mineralien der Serpentin-, Chlorit- und Glimmer-
gruppe, 205- — H. Traube. Ueber die Doppelsalze des weinsauren Anti-
monoxyd-Bleis und -Baryums mit salpetersaurem Kalium, 245. — A. G.
Hogbom. Ueber Dolomitbildung und dolomitische Kalkorganismen,
269 — II. Traube. Ueber die kiinstliche Darstellung des Berylls, 215. —
G. Steinmann. Ueber Thecospira im rhatischen Sandstein von Niirtingen,
2IfL — A. Wichmann. Ueber das Vorkommen fossiler Holzer im Feuer-
etein, 277. — B. Hecht. Zweite Bemerkung zu dem Satze, nach welchem
Symmetrieaxen immer mogliche Krystallkanten sein sollen, 2I&
Vol. 50.]
ADDITIONS TO THE LIBRARY.
221
Stuttgart. Neues Jahrbuch fiir Mineralogie, Geologie and Paliion-
tologie. Jahrgang 1894. Band ii. Heft L 1894.
V. Wohrmann. Alpine und ausseralpine Trias, L — F. Rinnie. Beitrag
«ur Kenntniss des Skolezits, 5L — J. C. Moberg. Ueber schwedische
Kreidebelemniten, CO. — G. Steinmann. Ueber das Ambulacralfeld von
Pentremites, Z1L — E. yon Fedorow. Erwiderung auf die Bemerkungen zu
E. von Fedorow's Elementen der Gestaltenlehre von E. llesa, 8& — E. Hess.
Weitere Bemerkungen zu E. von Fedorow's Elementen der Gestaltenlehre,
88. — F. von Sandberger. Spfuerium pseudocorneum, Reuss sp., im vulcan-
ischen Tuff der Eifel, 9£L=0. Behrendsen. Bemerkung zu der Abhand-
lung des Herrn Moricke : " Versteinerungen des Lias und Unteronliths
Ton Chile," £LL — F. von Sandberger. Ueber die Gerbllo des Bunteand-
steins, besonders jenes des nordlichen Schwarzwaldes und deren Herkunft,
tifL — M. Schlosser. Bemerkunpen zu Riitimeyer's 1 Die eocane Sauge-
thierwelt von Ecerkingen,' JjUtL — F. von Sandberger. Ueber Dolerit
von Djedda bei Mekka, ML
. . Beilage-Band viii. Heft IL 1893.
F. D. Adams. Ueber das Norian oder Ober-Laurentian von Canada,
419. — II. Traube. Ueber die Krystallforin einiger weinsaurer Salze, 499,
62'J. — II. Traube. Ueber die Krystallforin optisch einaxiger Subatanzen ,
deren Losungen ein optisehes Drehungsvermbgen besitzen, ft 10. — O.
Miigge. Untcrsuchunpen iiber die u Lenneporphvre " in Westfalen und
den an«m?nzenden Gebieten, /)-?"> — W. Ramsay, tlebcr Eudialyt von der
Halbinsel Kola, 722.
. . Beilage-Band ix. Heft L 1894.
W. Mbricke. Versteinerungen des Lias und Unteroolith von Chile, L.
— L. Milch. Beitrage zur Lehre von der R*»gionalmetamorphorto, 1Q1 .
— L. Milch. Zur Classification der anorganogenen Gesteine, LEL —
II. Traube. Ueber die pyroelektrischen Eigenschaften und die Krystall-
form des Prehnits, 1.*U. — II. Traube. Ueber die chemische Zusammen-
setzung und die Krystallform des kunstliehen Zinkoxyds und Wurtzits,
147. — H. Behrens. Versuche iiber Bildung von Spalten, Ilohlrtiuraen
und Steinkernen in Schuttkegeln, 1'>1. — G. A. F. Molengraaff. Beitrag
zur Oeologie der Umgegend der Goldfelder auf dem Hoogeveld in der
siidafrikanischen Republik, 174.
. Palaeontographica. Band xL Lief. 5 & fiL 1894.
Purchased.
1L Rauff. Palaeospongiologie, 232.
. . Band xli. Lief. 1 & 2. 1894. Purchased.
J. C. Merriam. Ueber die Pythonomorphen der Kansas-Kreide, L —
W. von der Marck. Vierter Nachtrag zu die fossilen Fische der west-
fhlischen Kreide, 41.— E. Bbse. Monographie des Genus Rhynchonellina,
Gemm., 4iL
. Verein fiir vaterliindische Naturkunde in "NVurttemberg.
Jahreshcfte. Jahrgang 41L 1893.
E. Fraas. Neues und altes iiber die Ichthyosaurier, xxxix. — J. E.
Pombeckj. Palaeontologische Beziehungen zwischen den untersten
Liaszonen der Alpen und Schwabens, xlii. — W. Branco. Neue Beobacht-
ungen iiber die Natur. der vulkaniscbcn Tuflfriinge in der schwabischen
Alb und ihrem nijrdlichen Vorlande, L — J. P. Pompeckj. Beitrage zu
einer Revision der Ammonitendes schwabischen Jura, 1&L — A. Schmidt.
Erdbebenberichte aus Wiirttemberg und Hohenzollern fur die Zeit vom
L Miirz 1892, bis L Miirz 1893, 249.
222
ADDITIONS TO TTIK I.IBBAKV.
[Nov. 1894,
Swansea. South Wales Institute of Engineers. Proceedings.
Vol. xviii. Nos. a=4* 1893.
. . . See also Cardiff.
Switzerland. See Bern.
Sydney. Australasian Association for the Advancement of Science.
Report of the 4th Meeting, held at Hobart, Tasmania, 1 S&2.
1893.
T. W. E. David. Address to Section C, Geology and Palaeontology,
64.— A. B. Biggs. Tasmanian Earth Tremors, ¥58. — J. B. Kirklani
Occurrence of Gallium and Indium in a Blende from Peel wood, New
South Wales, 2iMI — A. W. Craig. Note on an Examination of Water
from Lake Carangamite, Victoria, 270. — A. J. Sach and N. T. W. Wils-
more. The Jarvisfield Mineral Water from Lake Carangamite, Victoria,
21^L — J. C. LLMingayle. Notes on some of the Mineral Waters of New
South Wales, 277. — D. Clark. Minerals of Eastern Gippsland, 285.—
A. Liversidge. On the presence of Magnetite in Certain Minerals and
Rocks, 2QfL — A. Montgomery and W. F. Ward. Notes on a Carbonaceous
Deposit in Silurian Strata at Beaconsfield, Tasmania, 321- — A. J. Sach.
On a sample of Cone-in-Cone Structure found at Picton, N.S.AV., 327.—
W. C. Ross. On the Occurrence of Lepidodendron near Bathurst,
N.S.W., 33->— F. D. Power. Notes on the late Landslip iu the Dande-
nong Ranges, Victoria, 337. — J. IL Harvey. The Application of Photo-
Saphy in Geological Work, '340. — F. Kayser. Mount Bischolf, 342.—
. Tate. On the Age of Mammaliferous Deposits in Australia, Ariel—
W. C. Ross. Notes on the Theory of Coral Reefs, 359. — J. C. Corlette.
Some alleged Indications of Catastrophe, 3(10. — T. W. E. David. Notes
on the Permo-Carboniferous Rocks ot New South Wales, 3t>4. — J. B. W.
Woollnough. Icelandic Notes, 412* — W. U. Moore. Magnetic Shoal
near Cossack, Western Australia, 410. — J. P. Thomson. Explorations
and Discoveries in British New Guinea, 419. — J. Eraser. Volcanic Phe-
nomena in Samoa in 1866, 440.
. Australian Museum. See Books. New South Wales.
. Linnean Society of New South Wales. Proceedings.
Series 2. Vol. vii. Part 4, 1893.
. . . . Vol. viii. Parts L=& 1893-94.
F. W. Hutton. On Dinoruu (?) Queensland*'*, L— C. W. De Vis.
Note on the Upper Incisor of Phascdomus, ]_L — T. W. E. David. Note
on the Occurrence of the Mineral Sphene in granite from Bathurst, 44*—
E. F. Pittinan and T. W. E. David. Note on the Occurrence of Lepido-
dendron in Upper Devonian Rucks at Mount Lanltoie, near Rydal. New
South Wales, 12L— J. Mitchell. Note on the Discovery of a Bone-
deposit in the Parish and Count v of Sandon, N.S.W., 127. — R. Ethe-
ridge, Jun., and J. Mitchell. Tne Silurian Trilobites of New ^o»th
Wales, with References to those of other Parts of Australia : Part JU
169. — R. Helms. On the recently observed Evidences of an extensive
Glacier Action at Mount Kosciusko Plateau, 349.
Taunton. Somersetshire Archaeological and Natural-History So-
ciety. Proceedings. Vols, i.-vi. 1849-55. 1851-56.
Purchased.
. . . Vols, viii.-xviii. 1858-72. 1859-74.
Vol. 50.]
ADDITIONS TO THE LIBRARY.
223
Taunton. Somersetshire Archaeological and Natural-History So-
ciety. Proceedings. Vols, xx.-xxxvi. 1874-90. 1875-91.
. . . Vols, xxxviu.-xxxix. 1892-93. 1892-93.
. . . General Index. Vols, i.-xx. 1876.
Tokio. College of Science, Imperial University. Journal. Vol. v.
Tart 4. 1893.
B. Koto. On the Cause of the Great Earthquake in Central Japan,
1891, 295.
. . . Vol. vi. Parts 2 & 3. 1893.
. Imperial University of Japan. (Teikoku Daigaku.)
Tho Calendar for the year XXV.-XXVI. Meiji. (1892-93.)
1893.
. See Yokohama.
Topeka. Kansas Academy of Science. Transactions. Vol. xiii.
1891-92. 1893.
R. Hay. Notes on some new species of fossil Cephalopoda, 37. — E. B.
Knerr. Notes on u Mountain Leather," from Red liock Uauon, Colorado,
70. — R. Hay. Additional note on the Brenham Meteorite, 75. — R. Hay.
Note on the occurrence of Granite in a Deep Boring in Eastern Kansas,
75. — E. B. Knerr. Notes on a pink Barite from Atchison Limestone,
76. — E. H. S. Bailey and E. (5. Case. On the composition of some
Kansas Building-Stones, 78. — R. Hay. Some characteristics of the
Glaciated Area of North-eastern Kansas, 104. — S. \V. "VVilliston. The
Niobrata Cretaceous of Western Kansas, 107. — S. W. Williston. An
interesting Food Habit of the Plesiosaurs, 121.
Toronto. Canadian Institute. Seventh Annual Report. Session
1893-94. 1894.
. . Transactions. Vol. iii. Part 2. 1893.
. . . Vol. iv. Part 1. 1894.
Turin. Reale Accademia delle Scienze. Atti. Vol. xxviii. Nos.
9-15. 1892-93. 1893.
F. Sacco. Sopra alcuni Asteroidei fossili, 739.
. . . Vol. xxix. Disp. 1-10. 1893-94.
G. Piolti. Contribuzioni alio studio della variolite del Mt. Giraont
(alta Valledi Susa), 118. — L. Colomba. Sulla Glaucofane della Beaume
(alta Vallo della Dora Riparia), 404.
. . Memorie. Serio 2. Tomo xliii. 1893.
C. F. Parona. Revisione della Fauna liasica di Gozzano in Piemonte, 1.
Vienna. Kaiserliche Akademie der Wissenschaften. Sitzungs-
berichte. Mathematisch-naturwissenschaftliche Classo. Band
ci. Hefte 7-10. 1892.
J. J. Jahn. Vorlaufiger Boricht iiber die Dendroiden des bohmischen
Silur, 642. — E. Mojsisovics. Die Hallstatter Entwicklung der Trias, 769
Digitized by Google
224
ADDITIONS TO THE LIMURY.
[Nor. 1894,
Vienna. Kaiserliche Akademie der Wissenschaften. Sitzungs-
berichte. Mathematisch-naturwissenschaitliche Classe. Band
cii. Abth. i. Hefte 1-7. 1893. 1893.
A. Bittner. Decapoden des pannonischen Tertiare, 10. — C. von Etiinga-
hausen. Ueber fosaile Pflanzenreste aus der Kreideformation Australiem,
126. — A. von Koenen. Ueber die Unter-oligocane Fauna der Mergel von
Burgas, 179.— F. Toula. Der Jura im Balkan nbrdlich von Sofia, 191.—
F. Becke. Ueber die Bestimmbarkeit der Gesteinsgemengtheile, beeondera
der Plagioklase, auf Grund ihres Lichtbrechungs-vermbgens, 358.
. . Dctikscbriften. Mathematisch-naturwisseiischaft-
licbe Classe. Band lix. 1892.
M. Neumayr und V. Uhlig. Ueber die von H. Abich im Kaukasus
gjsammelten Jurafo&silien, 1. — Franz Ritter von Hauer. Beitrage zur
enntnissder Cephalopoden aus der Trias von Bosnien, I., 251. — F. Toula.
Geologische Untersuchungen im ostlichen Balkan und in anderen Theiien
von Bulgarien und Ostrumelien, II., 409.— R. von Wettstein. Die fossile
Flora der Hbttinger Breccie, 479.
. Kaiserlich-konigliche Bergakademie zu Leoben und Pribram
und die Kbniglich-ungarische Bergakademie zu Schemnitx.
Berg- und Huttenmannischee Jahrbuch. Band xli. Hefte 2-4.
1893.
. . . Bandxlii. Heft 1. 1894.
F. Kupelwiesser. Einige Worte iiber die Regulirungsarbeiten an den
Katarakten der unteren Donau, 29. — J. Schnablegger. Verfahren Torf,
Lignit und Braunkohle zu vercoken, 45. — A. Tachebull. Kara tens Stein-
und Braunkohlenformation in nationalokonomischer Beziehung, 51.—
F. Poseimy. Ueber die Entstehung der Blei- und Zinklagerstatten in
auflbslichen Gesteinen, 77.
. Kaiserlich-konigliche geologische Reichsanstalt. Abhand-
lungen. Band vi. 2 HiUfte. (Text and Plates.) 1893.
E. Mojsisovics von Mojsvar. Die Cephalopoden der Hallstatter Kallre,
Abth. i., 1.
. . . Band xv. Heft 4. 1893.
G. Geyer. Die mittelliasische Cephalopoden-Fauna des Hinter-Schaf-
berges in Oberbsterreich, 1.
. . . . Heft 5. 1893.
T. G. Skupbos. Ueber Partanosaurw Zitteli, Skuphos, und MtcroUp'
tcomurus Schlos$eri, nov. gen., nov. spec, aus den Vorarlberger Partnach-
schicbten, 1.
. . . . HeftG. 1893.
A. nofinann. Die Fauna von Gbriach, 1.
. . . Bandxvii. Heft 3. 1893.
A. Kornhuber. Carsosaurus Marchesettii, ein neuer fossiler Lacertilier
aus den Kreideschichten des Karstes bei Komen, 1.
. . Jahrbuch. Jahrgang 1893. Bandxliii. Hefte 1-4.
1893-94.
S. Frh. von Wbhrmann. Ueber die systematische Stellung der Trigon-
iden und die Abstammung der Nayaden, 1. — E. Tietze. Zur Geologie
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
225
der Gegend von Ostrau, 29. — A. Rosiwal. Zur Fauna der Pbtzleindorfer
Sande, 8_L — E. Tietze. Beitrage zur Geologic von Galizien, 89. — V. J.
Prochazka. Ueber die Fauna der durch das Bohrloch nachst Gross-
Onatovice durchteuften Neogengebilde, 125. — A. Bittuer. Neue Koninck-
iniden des alpinen Lias, 133. — T. G. Skuphos. Ueber die Entwicklung
und Verbreitung der Partnachschicliten in Vorarlberg und iui Fiirsten-
thum Liechtenstein, 145. — A. Nehring. Ueber pleistocane Ilanister-
Reste aus Mittel- und Westeuropa, 179. — C. M. Paul. Das Siidwest-
Ende der Karpathen-Sandsteinzone (Marsgebirge und Steinitzer Waldin
Mahren), 109. — L. von Tausch. Resultate der geologischen Aufnahinen
des nbrdlichen Theiles des Blattes Austcrlitz nebst Bemerkungen iiber
angebliche Kohlenvorkonimnisse im untersuchten Culmgebiete, 25Z. —
IL Dietrich. Chemische Analyse der Klebelsbergquelle ira Salzberge
von Ischl, 215. — V. Hiiber. Das Tertiiirgebiet um Graz, Kbflach und
Gleisdorf, 28L — S. Brusina. Die fossile Fauna von Dubovac bei Karl-
stadt in Kroatien, SflB. — F. Karrer. Geologische Studien in den tertiiiren
und jiingeren Bildungen des Wiener BecKens, 377. — E. Tietze. Dio
geognostischen Yerhaltnisse der Gegend von Olinutz, 399. — K. A. Penecke.
I)as Grazer Devon, 567.— S. von AVohrinann. Die Raibler Schichten,
nebst kritischer Zusanimenstellung ihrer Fauna, G17.
Vienna. Kaiserlich-koniglicho geologische Reichsanstalt. Ver-
handlungen. 1893. Nos. 0-18. 1893.
A. Bittner. Ueber die Gattung Oncophora, 14_L — L. von Tausch. Be-
richt iiber die geologische Aufnahnie des nbrdlichen Theiles des Blattes
Austerlitz (Kartenblatt Zone 9^ Col. xvi.), 145. — A. Rosiwal. Aus deni
krystallinischen Gebiete zwischen Schwarzawa und Zwittawa, 14ii. —
A. Bittner. Partnachschicliten mit Koninckina Leonhardi im Thale von
Kaltenleutgeben nachst Wien, LfiL — A. Kornhuber. Ueber einen neuen
fossilen Saurier von Komen auf dem Karate, 105. — F. Teller. Ueber den
sogenannten Granit des Bachergebirges in Siidsteiennark, Lflfl. — M.
Scnlosser. Geologische Notizen nus dem bayrischen Alpenvorlande und
dem Innthale, 188. — F. Katzer. Fine Entgegnung an Ilerrn Dr. J. J.
Jahn, 198. — F. Eichleiter. Ueber die chemische Zusammensetzung
einiger Gesteine von der Halbinsel Kola, 217. — F. Wiesbaur. Das Vor-
kommen von Pyropen um Krendorf bei Laun, 219. — A. Bittner. Ueber
die Nothwendigkeit, den Terminus " norisch fiir die Hallstatter Kalke
aufrecht zu erhalten, 220. — A. Rzehak. Geographische Bemerkungen
iiber einige Fossilienfundorte des Wiener Beckens, 23Z. — C. Moser.
Bericht iiber den Stand des Queeksilber-Bergbaues im Wippachthale in
Innerkrain, 23ii — E. Bbse und H. Finkelstein. Nochmals die mittel-
jurassischen Brachiopodenschichten Lei Castel Tesino, 239. — M. Kispatic".
Meerschaum aus Ljubic-planina bei Prujavor in Bosnien, 241. — F. von
Kerner. Ueber die Aufnahmsthatigkeit im Gebiete von Dernis in
Dalmatien, 242» — A. Bittner. Aus der Unitrebung von Schwarzau im
Gebirge, 245. — G. von Bukowski. Reisebericht aus dem siidlichen
Dalmatien, 247. — A. Bittner. Berichtigung zu R. Hoernes' neuester Mit-
theilung iiber die u Solzkaschichten," 252. — A. Bittner. Einige Bemer-
kungen zu Gauthier's Besprechung meiner Mittheilung" " Ueber Para-
brums und einige andere alttertiare Echinideniyattungen,' 258. — E. Tietze.
Aus der Gegend von I^andskron in Bbhmen, 2G3. — J. J. Jahn. Ueber
das Tejrovicer Cambrium (Bbhmen), 207. — E. Tietze. Ein neues Neo-
genvorkommen bei Odrau in Schlesien, 27.'t. — J. J. Jahn. Bericht iiber
die Aufnahmsarbeiten im Gebiete von Hohennitfutb-Leitoniischl (Karten-
blatt Zone 0^ Col. xiv.). — A. Rzehak. Beitrag zur Kenntniss der dilu-
vialen Conchy lienfauna Mahrens, 2&L — T. Fuchs. Berichtigung zu
Rzehak's " Geographische Bemerkungen iiber einige FossUienfunaorte
226
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
des Wiener Beckens," 285. — A. Bittner. Bemerkung zu der letzten
Mittheilung von E. Bose und II. Finkelstein iiber Brachiopodenschichteo
von Castel Tesino, 28JL. — J. Dreger. Notiz iiber ein Petroleum-Var-
koramen in Sudsteiermark, 287. — A. Rosiwal. Aus dem krystallinbchen
Gebiete des Oberlaufes der Schwarzawa, 28L — A. Bittner. Aus dem
Unigebungen von Nasswald und von Rohr im Gebirge, 295. — K. Redlica,
Eine neue Fundstelle miocaener Fo&silien in Mahren, 309. — E. Doll
L Quarz nach Amphibol, eine neue Pseudomorphose. II. Ein neuer
Fundort von Katzenaugen. III. Quarz pseudomorph nach Kalkspath.
IV. Avanturisirender Glasquarz, 318. — A. Bittner. Aus dem Schwara-
und dem Hallbachthale, 32& — J. J. Jahn. Ueber die sogenannte Riicken-
lippe bei den Scaphifcen und iiber Gvilfordia acanthochila, Weinz. sp^
34iL — A. Rosiwal. Aus dem krystallinischen Gebiete des Oberlaufes der
Schwarzawa, 847. — E. Tietze. Ueber das Verhaltnias von Culm und
Devon in Mahren und Schlesien, 355. — A. Rosiwal. PetrogTaphieche
sowie Quarzite aus der Umgebung des Radstadter Tauern, 865. — J. J.
Jahn. Einige Bemerkungen iiber das bohmische Silur und iiber die
Bildung des Erdbls, 322. — E. Kittl. Das Gosauvorkomraen in der Einod
ihre Umgebung, 382. — F. von Sandberger. Die Gattung Oncophora Rzeb.,
401 . — M. Vacek. Einige Bemerkungen iiber das Magnesitvorkomraeu
am Sattlerkogel in der Veitsch und die Auffindung einer Carbonfaun*
daselbst, 401. — G. Geyer. Ueber die Stellung der altpnlaeozoischen
Kalke der Grebenze in Steiermark zu den Griinschiefern und PbylkteD
von Neumarkt und St. Lambrecht, 400.
Vienna. Kaiserlich-konigliche geologischo Reichsanstalt. Ver-
handlungen. 1804. Xos. L=fL 1894.
G. Stache. Jahresbericht des Directors, L — A. Bittner. Entgeguung
an Herrn A. Rothpletz in Miinchen,61. — J. Dreger. Geologische Bescnreib-
ung der Umgebung der Stadtf Pettau und Friedau und des ostlichen
Theiles des Kollosgebirges in Siidsteicrmark, &L — F. von Kerner. Ueber
die geologischen Verhaltnisse der Gegend von Dernis in Dalmatien, 75 —
A. Bittner. Einige Bemerkungen zu A. Rothpletz's " Ein geologiscber
Querschnitt durch die Ostalpen, 8L — G. Geyer. Zur Stratigraphie der
palaeozoischeu Schichten in den Karnischen Alpen, 102. — G. Bukow?ki.
Geologische Mittheilungen aus den Gebieten l'astrovicchio und Spiza
in Siiddalmatien, 120. — J. N. Woldrich. Eigenthiimliche Concretionen
im sarmatischen Sand bei "Wien, 131 . — C. von John. Noritporphyrit
(Enstatitporphyrit) aus den Gebieten Spizza und Pastrovicchio in Siid-
dalmatien, 133. — A. Rosiwal . Aus dem krystallinischen Gebiete des
Oberlaufes der Schwarzawa, 1 30. — J. J. Jahn.* Ueber bemerkenswerthe
Fossilientypen aus dem biihmischen Cambrium, 148.
. Kaiserlich-koniglicbes naturhistorisches Hofmuseum. An-
nalen. Band viii. Xos. 2=4. 1893.
F. Toula. Die Miociinablagerungen von Kralitz in Mahren, 283.—
F. Berwerth. Ueber Alnoit von .Vino, 440.
*
. Kaiserlich-konigliche zoologisch-botanische Gesellschaft.
V^rhandlungen. Jahrgang 1893. Band xliii. Quartal l-3«
— . Mineralogische und petrographische Mittheilungen. Nene
Folge. Band xiii. Hefte 1=(L 1893. Purchased.
H. Lechleitner. Neue Beitrage zur Kenntniss der dioritischen Gesteio©
Notizen iiber einige krystallinische
1893.
"Vol. 50.]
ADDITIONS TO THE LIBRARY.
227
Tirols, 1. — H. P. Cushing und E. Weinschenk. Zur genauen Kenntniss
der Phonolitho des Ilegaus, 18. — P. Grosser. Die Trachyte und Ande-
site des Siebengebirges, 30. — O. Lang. Beitriige zur Systematik der
Eruptivgesteine, 1 15. — B. Frosterus. Ueber ein neues Vorkommnis von
Kugelgranit unf'ern Wirvik bei Borga in Finland, nebst Bemerkungen
iiber iihnliche Bildungen, 177. — E. 0. Hovey. Ueber Gangdiabase der
Gegend von Rio de Janeiro und iiber Salit von Sala in Schweden, 211. —
J. v. Szadeczky. Der Granit der llohen Tatra, 222. — O. Beyer.
"Weitere Mittbeilungen iiber granitisehe Einschliisise in Basalten der
Oberlausitz, 231. — J. Blumrich. Ueber die sogenannte Sanduhrform der
Augite, 239. — S. Kniittel. Bericht iiber die vulcanischen Ereignisse ira
engeren Sinne wahrend des Jahres 1892, 266. — R. Beck. Die Contact-
hofe df»r Granite und Syenite im Schiefergebiete des Elbthalgebirges,
290. — R, Herz. Ueber die Zonarstructure der Plagioklase, 343. — H.
Pfahler. Ueber den Meteoriten von Barbotan, 24 Juli, 1790 : Ueber den
Meteoritcn von l'Aigle, 26 April 1803, 353.— F. Hornung. Beitrng zur
Kenntniss der Ostharzer Eruptivgesteine, 373. — F. Becke. Petro-
fraphische Studien am Tonalitder Reiserferner, 379, 433. — J. Blunireicb.
)ie Phonolithe des Friedliinder Bezirkes in Nordbohmen, 465. — O. Lang.
Beitriige zur Systematik der Eruptivgesteine, 496. — A. Model. Molybdan-
verbindungen im Serpentin des Rotheukopfs, Zillerthal, 532.
Vienna. Mineralogische und pctrographischo Mittheilungen.
Neue Folge. Band xiv. Hefte 1 & 2. 1894. Purchased.
A. Pelikan. Ueber Gothit, Limonit und rotben Glaskopf, 1. — G. C.
Laube. Ueber das Vorkoramen von Baryt und Hornstein in Gangen im
Porphyr von Teplitz, 13. — A. Dannenberg. Studien an Einscliliissen in
den vulcanischen Gesteinen des Siebengebirges, 17. — E. v. Fedorow.
Mineralogisches aus dem niirdlichen UraF, 85. — J. E. Ilihsch. Beitriige
zur Geologie des bdhmischen Mittelgebirges, 95. — J. A. Ippen. Ueber
synthetische Bildung von Zinnoberkrvstallen, 114. — A. Frenzel. Mine-
ralogisches, 121. — V. Goldschmidt. Iteber Wiisten^toine und Meteoriten,
131. — E. von Fedorow. Mineralogisches aus dem niirdlichen Ural, 143. —
P. Kretschnier. Die Mineralfundatatten von Zciptnu und Umgebung,
166.
Washington. Congrea G<5ologique International. See Books.
Congres Geologique International.
. Smithsonian Institution. Annual Report of the Board of
llegents showing the Operations, Expenditures, and Condition
of the Institution to July 1891. 1893.
C. Chree. Some Applications of Physics and Mathematics to Geolopy,
127. — E. Orton. Origin of the Rock-pressure of Natural Gas, 155. — W.
H. Weed. Geysers, 163.
. . Smithsonian Contributions to Knowledge. Vol.
xxix. No. 842. 4to. 1892.
. . . [Vol.—.] No. 884. 4to. 1893.
. . Smithsonian Miscellaneous Collections. Vol. xxxi.
8vo. 1893.
. . . Vol. xxx vi. 8vo. 1893.
. . ■ . No. 844. Smithsonian Meteorological Tables.
(Based on Guyot's Meteorological and Physical Tables.) 8vo.
1893.
2 28 ADDITIONS TO THE LIBRARY. [Nov. 1894.
Washington. Smithsonian Institution. See Books : STurborn,
C. Davits.
. . Bureau of Ethnology. Eighth Annual Report.
1836-87, by J. W. Powell, Director. 1891.
. . . Ninth Annual Report of the Bureau of
Ethnology to the Secretary of the Smithsonian Institution,
by J. W. Powell, Director. 1886-87. 1892.
. . . Bibliography of the Chinookan Languages,
by J. C. Pilling. 8vo. 1893.
. . . Bibliography of the Salishan Languages, by
J. C. PUling. 8vo. 1893.
. . Annual Report of the Board of Regents for the year
ending June 30, 1890. Report of the United States National
Museum. 8vo. 1891.
G. P. Merrill. Handbook for the Department of Geology in the U.S.
National Museum. — Part I. Geognosy. The Materials of the EartA'a
Crust, 503.
. . United States National Museum. Annual Report
of the, for the year ending June 30, 1891. 8vo. 1S92.
. . . Bulletin. No. 40. 1892.
. . . . No. 43. 1894.
. . . . Nos. 44, 45, 46. 1893.
. . . Proceedings. Vol. xiv. 1891. 1892.
E. D. Cope. On the character of some Palaeozoic Fishes, 447.
. . . . Vol. xv. 1892. 1893.
W. M. Fontaine. Description of some Fossil Plants from the Great
Falls Coalfield of Montana, 487.
. . . Directions for collecting Birds, by R. Ridg-
way. 8vo. 1891.
. . . Directions for collecting Recent and Fossil
Plants, by F. H. Knowlton. 8vo. 1891.
— . . . Directions for collecting Reptiles and Batra-
chians, by L. Stejneger. 8vo. 1891.
. . . Directions for collecting and preserving
Insects, by C. V. Riley. 8vo. 1892.
. . . Instructions for collecting Mollusks and
other useful hints for Conchologists, bv W. H. Dall. 8vo.
1892.
Wellington College. Wellington College Natural Science Society.
24th Annual Report, 1893. 1894. Presented by Horace W.
Monckton, Esq., F.GJS.
Digitized by Googl
Vo*- 5°0 ADDITIONS TO THE LIBRAE F.
WeU^d^ Z°' * Books: New
^iwirv^.1!^ Actions and Proceedings.
Pinimithi^ l'-T°j PwSf"8??^ ind Mut°!a Nations of the
certain Species of Moa 3 F w S^F*""!" of a Creat of Feathers
w. ifutton. ^i^^^^^fr of Mom,
The Moas and the Moa-huntew a -l A^e 9uatrefaff*.
and Caves at the Castle Ss a ■ J*00' 0n the Fissures
IWainsof Existing f ^ a Deacription of the
Artesian-water lC! TVx^Ct Blrd* found 111 the«n, 88.-H. Hill
Hill XrtesianV™;
SujpTy, Ruataniwhn Plain aw - J Sa n*?^ °f Artesian Water"
ana Gneissic Rocks in thf \^ ^:£^\K?D %e °c<™™nce of Granite
quake of the 4th 8&£-a. -Hogben. The Earth-
Andeeite of Banks Pen insu £ ■ S ' ^rf' Spei£ht 2? « Se-
near Pakaraka, Bay of" Sandf Z V^t* 5V Matom ^P08*
nature of Stinkstone ( Ant & \Vu?-Iand£, 8p-W- ^J- On the
of the Moa,41^-T^ The Extinction
— G. Mair On t^ iJZ -t 9* Remains of Moa in the Forest. 504
• mair. Un the Antiquity of the Moa, 634 h
2jF. von Sandberger. Zur Geobgie der Gegend von Homburg v. d. Hohe,
J. Conder a!a jJ'*, A Vol. xvm. 1893.
l.^oWMiWChl^Nfott 0Vhe S^f^rthqpato of October
03.-E. Rebeur Pa £h wit^nJ £ * <5*P * the Brftiflh ^^tion,
Wares at -eat d^lTf^^tS^^ °f Great Earthq.iake
Great Earthquake Tl^ T^T*^ Relation to the
the Overtu Jng, of «£S^ Jdy ^ 1889,Vll.-F. Omori. On
TOrki893Nat,lral **** Jouraal- ™* Nos. 150-153.
"Fw^iifl Y°l'x™' Nos. 154-158. 1894.
seum, South TL^m™^^™** tJe Natural History Mu-
^^ffton, H. W.Jones. A Visit to Wairakei, 72.
~1893.°r Mosophical 8ociety. Annual Report for 1802.
flfcire Oolites, &47 -Sr*!?? J""5 Wopoda recently discovered in the York-
\.ML Notes on eZ t^' ^ Omo^n« PA^„; Seeley, 62.-
8i ost-Tertiary Deposit in Sussex, 58.
^Annual Report for 1893. 1894.
V* of the Juraasil ^'bourhaod of York 56.-J. W. Gregory.
^ -°r.ro2oa m the York Museum, 58.
Digitized by Google
230
ADDITIONS TO THE LIBRAKY.
[Not. 1894.
2. Books.
Names of Donors in Italics.
Abbott, W. J. Lewis. The Ossiferous Fissures in the Valley of the
Shodo, near Ightham, Kent. 8vo. London, 1894.
. See Newton, E. T.
Adan do Yarza, Ramon. See Spain.
Aguilera, J. G., y E. Ordonez. Datos para la Gcologia de Mexico.
8vo. Tacubaya, 1893.
Alabama. Geological Survey. (E. A.Smitli, State Geologist.) Ik-
port on the Coal Measures of Blount Mountain, by A. M. Gibson.
8vo. Montgomery, Ala., 1893.
. . ( .) Report on the Geological Structure of
Murphrce's Valley and its Minerals and other materials of
economic value, by A. M. Gibson. 8vo. Montgomery, 1893.
Allen, R. Allen's Illustrated Guide to Nottingham and the Neigh-
bourhood. 8vo. Nottingham, 1893. Presented by L. L. Belin-
fante, Esq., B.Sc.
Almera, J. See Spain.
Althaus, R. Die Erzformation des Muschelkalks in Oberechlesien.
(Festschrift zu dem V. Allgemeinen Deutschen Bergmannstag ii>
Breslau, 1892.) 8vo. Berlin, 1892. Presented by H. Bauer-
man, Esq., F.O.S.
. Riegelbildungen im Waldenburger Steinkohlengebirge.
Festschrift zu dem V. Allgemeinen Deutschen Bergmannstag in
Breslau, 1892.) 8vo. Berlin, 1892. Presented by H. Bauer-
man, Esq., F.O.S.
Ammon, L. von. See Bavaria.
Anderson, "W. See New South Wales.
Andersson, J. O. Uober Blocke aus dem jiingeren Untersilur auf
der Insel Oland vorkommend. 8vo. Stockholm, 1893.
Andra, C. J. Lehrbuch der Oryktognosie. 8vo. Brunswick, 1864.
Purchased.
Andreac, A. See Baden.
Ansted, D. T. The Ionian Islands in the year 1863. 8vo. h>*
don, 1863. Purchased.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
Arkansas Geological Survey. (J. C. Branner, State Geologist.)
Annual Report for 1888. (In four volumes.) Vols, i.-iv. by
J. C. Branner. 8vo. Little Rock. Vols. i. & ii., 1888 ; Vol. iii.,
1891 ; Vol. iv., 1888. Purchased.
. . ( .) Annual Report for 1889. VoL ii. Geology
of Crowley's Ridge, by R. E. Call. 8vo. Little Rock, 1891.
Purchased.
. . ( .) Annual Report for 1890. Vol. i. Man-
ganese, by R. A. F. Penrose, jun. 8vo. Little Rock, 1891.
Purchased.
. . ( .) -. Vol. ii. The Igneous Rocks of
Arkansas, by J. F. Williams. 8vo. Little Rock, 1891. Pur-
chased,
. . ( .) . Vol. iii. Whetstones and Novacu-
lites of Arkansas, by L. S. Griswold. 8vo. Littlo Rock, 1892.
Purchased.
. . ( .) . Vol. iv. Marbles and other Lime-
stones, by T. C. Hopkins. Text, and Atlas. 8vo. Little Rock,
1893. Presented by the State Geologist.
. . ( .) Annual Report for 1891. Vol. i. Mineral
Waters of Arkansas, by J. C. Branner. 8vo. Little Rock, 1892.
Presented by the State Geologist.
. . ( .) Annual Report for 1892. Vol. i. Iron
Deposits of Arkansas, by R. A. F. Penrose, jun. 8vo. Little
Rock, 1892. Presented by the State Geologist.
Army Medical Department. Report for the year 1891. Vol. xxxiii.
8vo. London, 1893.
1
1892. Vol. xxxiv. 8vo. London, 1894.
Arnould, G. Bassin Houiller du Couchant de Mons. 4to. Mons,
1878. Purchased.
Aubert, F. Explication de la Carte Gdologique Provisoire de la
Tunisie. 8vo. Paris, 1893. Purchased.
. See Maps.
Australasia. Report of the Committee on Seismologies! Phenomena
in Australasia. See ffogben, G.
Austria. Kaiserlich-kbnigliche geologische Reichsanstalt. See
Periodicals. Vienna.
Baden. Ministerium des Innern. Mitthoilungen der Grossherzoglich
Badischcn geologischen Landesanstalt. Band ii. Heft 4. 8vo.
Heidelberg, 1803. Purchased.
C. Lent. Der westliche Schwarzwaldrand zwischen Staufen und
vol. L.
I
232 ADDITIONS TO THE LIBRARY. [NOV. 1 894,
Badenweiler, 645.— A. Andreae und A. Osann. Loss und Lbsslehm be
Heidelberg, ihre Hohenlage und die darin Torkommenden Mineralien,
733. — G. Steinmann. Ueber die Gliederung dee Pleistocan im badi&chen
Oberlande, 743.— A. Sauer. Porphyretudien, 793. — P. Plata. Die
G lacialbildungen des Schwarzwaldes, 837.
Baden. Ministerium dee Innern. Mittheilungen der Groesherzoglich
Badischen Geologischen Landeaanstalt. 1. Erganznng zum
I. Band. 8vo. Heidelberg, 1893. Purchased.
H. Eck. Verzeichniss der mineralogischen, geognostischen ur-(Yor-)
geschichtlichen und balneo^raphiacheij Literatur von Badeu, Wurttem-
Eerg, HohenzoUern und eimgen angrenzenden Gegenden. Nachtrage und
late Forsetzung.
Bain, T. C. J. See Jones, T. Rupert.
Barbour, E. H. Notes on a new Order of Gigantic Fossils. 8vo.
1892.
Baretti, M. Geologia della Provincia di Torino. Text, 8vo. Atlas,
fol. 1893. Purchased.
Barlow, W. Ueber die geometrischen Eigenschaften homogener
starrer Structuren und ihre Anwendung auf Krystalle. Sw.
Leipzig, 1894.
Barris, W. H. See Illinois.
Barrois, C. See Spain.
Barns, C. See United States.
Bather, F. A. The Crinoidea of Gotland.—- Part I. The Crinoidea
Inadnnata. 4to. Stockholm, 1893.
Bauerman, H. Iron and Steel at the Chicago Exhibition. 8vo-
London, 1894.
Bavaria. Koniglich Bayerischcs Oberbergami. Geognostische Ab-
theilung. Geognostische Jahreshefte. 5ter Jahrgang. 1892.
8vo. Munich (Cassel). 1893.
H. Thiirach. Ueber die Gliederung des Urgebirges im Spossart, 1.—
L. von Ammon. Die Gastropodenfauna des Hochfellen-Kalkes und
iiber Gastropoden-Keste aus Ablagerungen von Adnet, vom Monte Not*
und den Raibler Schichten, 161.
Bavhini, Caspari. Be Lapidis Bezaar. 12mo. Basle. 1613.
Purchased.
Bayley, W. S. Eleolite-syenite of Litchfield, Maine, and Hawee'
Hornblende-syenite from Red Hill, New Hampshire. Svo,
Rochester, N.Y., 1892.
. A Summary of Progress in Mineralogy and Petrography in
1893. 8vo. Waterville, Me., 1894.
Digitized by Googl
Vol. 50.] ADDITION8 TO THE LIB BAB T. 233
Beecher, O. E. A Larval Form of Triarthrus. 8vo. Now Haven,
1893.
. Larval Forms of Trilobites from the Lower Helderberg
Group. 8vo. New Haven, 1893.
. On the Thoracio Legs of Triarthrus. 8vo. New Haven,
1893.
. Some Correlations of Ontogeny and Phylogeny in the Bra-
chiopoda. 8vo. Philadelphia, 1893.
. On the mode of Occurrence, and the Structure and Develop-
ment of Triarthrus Bechi. 8vo. Rochester, N.Y., 1894.
. The Appendages of the Pygidium of Triarthrus. 8vo.
Rochester, N.Y., 1894.
Behrens, H. Beitrage zur Petrographio des Indischen Archipels.
Hefte 1 & 2. Amsterdam, 1880 & 1883. Purchased.
. Mikrochemische Methoden zur Mineral-Analyse. 8vo.
Amsterdam, 1882. Purchased.
. Uebereigenthuemliche Krystallgebilde in einem vulkanischen
Gestein von der Insel Timor. 8vo. Amsterdam, 1883. Pur-
chased.
Berghell, H. See Finland.
Bertrandy C. E., et B. Renault. Reinschia australis et premieres
remarques sur le Kerosene Shale de la Nouvello Galles du Sud.
8vo. Autun, 1894.
Bertrand, Marcel. Lignes directrices de la geologie de la France.
4to. Paris, 1894.
. Sur la Structure des Alpcs fran^aises. 4to. Paris, 1894.
Bigot, A. Contributions a l'dtudo de la Faune Jurassique de Nor-
mandie. lp Meraoire sur les Trigonies. 4to. Caen, 1893.
Bittner, A, Zur neueren Literatur der alpinen Trias. 8vo.
Vienna, 1894.
Blake, J. F. See Pebiodicals. London. Annals of Geology.
Blake, W. P. The Existence of Faults and Dislocations in the
Lead and Zinc Regions of the Mississippi Valley, with Observa-
tions upon the Genesis of the Ores. 8vo. New York, 1893.
. The Mineral Deposits of South-west Wisconsin. 8vo.
New York, 1893.
. The Progress of Geological Surveys in the State of Wisconsin.
8vo. Madison, 1893.
s2
2 J4 ADDITIONS TO THE LIBRARY. [Nov. 1 894.
Kale*, W. P. The Separation of Blende from Pyrites : a new Metal-
lurgical Industry. Sto. New York, 1893.
. Wisconsin Lead and Zinc Deposits. Svo. Rochester, N.Y.,
1893.
. The Zinc-Ore-Deposits of South-western New Mexico. 8vo.
New York, 1894.
Blanckenhorn, Max. Die Strnkturlinien Syriens nnd des Roten
Meeres. (F. Fr. von Richthofen, Festschrift, 115.) 8vo. Ber-
lin, 1893. Purchased.
Blomberg, A. See Sweden.
Blondeau, — . Manual de Mineralogia. 2** edicion, traducido al
Castellano por M. G. Vara. 8vo. Madrid, 1831. Purchased.
Bo fill, A. See Spain.
Bohemia. Landesdurchforschungs-Comite. Archiv der naturwissen-
schaftliche Landesdurchforschung. Band ix. No. 1. (Geologische
Abtheilung.) 8vo. Prague, 1893.
A. Fric. Studien im Gebiete der bohmischen Kreideformation.
Palaontologische Untersuchungen der einzelnen Schichten : V. Prieeener
Schichten, 1.
Bombicci-Porta, L. Riven dicazione della priorita degli studj e delle
conclusioni sul sollevamento delT Appennino Emiliano per via di
scorrimento e di prcssioni laterali e la diretta azione della graviti.
8vo. Bologna, 1893.
Bonney, T. G. The Story of our Planet. 8vo. London, 1S93.
Bose, P. N. See India.
Branner, J. C. See Arkansas.
Briart, A. Geologic des environs de Fontaine-l'Eveque et de Lan-
delies. 8vo. Liege, 1894.
British Museum (Natural History). Catalogue of the Mesoxoic
Plants in the Department of Geology. The Wealden Flora.
Part I. Thallophyta-Pteridophyta, by A. C. Seward. 8vo.
London, 1894. Presented bu the Trustees.
Brodie, P. B. Notes on the Eocene Tertiary Insects of the Isle of
Wight. Svo. London, IS 93.
. Notice of a Section in the Lower Lias at the Cement Works,
near Rugby. Svo. Warwick, 1S»4.
. Notice of a Section in the Middle Lias at Naptoo. Svo.
Warwick, 1S94.
. On additional remains of Cestraoont and other Fishes in the
Green Mark immediately overlying the Red Maris of the Upper
Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
235
Keuper in Warwickshire, with an account of the equivalent Beds
in Germany and the Tyrol. 8vo. Warwick, 1894.
Brodie, P. B. President's Address to the Warwickshire Naturalists*
and Archaeologists' Field Club. 8vo. Warwick, 1894.
Brown, II. T. L. Catalogue of South Australian Minerals, with the
Mines and other Localities where found ; and Brief Remarks on
the Mode of Occurrence of some of the principal Metals and Ores.
8vo. Adelaide, 1893.
Brown, T. See Periodicals. Wellington, N. Z.
Browne, Montague. A Contribution to the History of the Borough
of Leicester. 8vo. Leicester, 1893.
■
Bucking, H. See Maps. Attica.
Bucktnan, S. S. u The Top of the Inferior Oolite ■ and a Correla-
tion of " Inferior-Oolite " Deposits. 8vo. Dorchester, 1893.
Bukow&ki, Oejza v. Die levantinische Molluskenfauna der Insel
Rhodus. L Theil. 4to. Vienna, 1893.
. Reisebericht aus dem siidlichen Dalmatien. 8vo. Vienna,
1893.
. Ueber den Ban der siidlichen Sudeten auslaufer ostlich von
der March. 8vo. Vienna, 1893.
Burst, Amedee. M6moire sur les relations des Roches Trappeennes
avec les Minerais de Cuivre ct de Fer, et sur l'Assimilation des
Schalsteins du Dillenburg, des Blattersteins du Harz et des
Gabbros de la Toscane. 8vo. Saint-Etienne, 1848. Purchased.
. Mineralogie Appliquee. 8vo. Paris, 1864. Purchased.
-. Traite du Gisement et de la Recherche des Mineraux Utiles.
5me edition. Parties ln et 2me. 8vo. Paris, 1870. Purchased.
Burkhardt, C. See Switzerland.
Cabanas, L. See Maps. Mexico.
Calderon, S., y F. Quiroga. Estudio petrogrdfico del Meteorito de
Guarena, Badajoz. 8vo. Madrid, 1893.
California State Mining Bureau [J. J. Crawford, State Mineralogist].
Eleventh Report of the State Mineralogist (Wm. Ireland, jun.,
late State Mineralogist). Two years ending September 15, 1892.
(First Biennial.) 8vo. Sacramento, 1893.
Call, R. E. See Arkansas.
Cameron, A. C. 0. Geology, Mining, and Economic Uses of Fullers'
Earth. 8vo. Newcastle-upon-Tyne, 1893.
236
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
Canada. Geological Survey. Annual Report. New series. 1S9U -91.
VoL v. Parts 1 and 2, and accompanying Maps. 8to. Ottawa,
1893.
. . Catalogue of Section I. of the Museum of the
Geological Surrey, embracing the Systematic Collection of Minerals
and the Collection of Economic Minerals and Rocks and Specimens
illustrative of Structural Geology, by G. C. Hoffman. Svo.
Ottawa, 1893.
. . Catalogue of a Stratigraphical Collection of Canadian
Rocks prepared for the World's Columbian Exposition, Chicago,
1893, by W. F. Ferrier. 8vo. Ottawa, 1893.
Cape of Good Hope. Department of Lands, Mines, and Agriculture.
Report upon the Geology and Mineral Resources of the Division
of Prince Albert and surrounding districts, by A. B. Sawyer.
4to. Cape Town, 1S93.
Card, G. W. See New South Wales.
Carez, L. France. [Extrait de l'Annuaire Geologique Universe!,
1891.] 8vo. Paris, 1892-93.
. lies Britanniques. [Extrait de l'Annuaire Geologique
Universel, 1891.] 8vo. Paris, 1892-93.
. Systeme Jurassique. [Extrait de l'Annuaire Geologique
Universel, 1891.] 8vo. Paris, 1892-93.
. Reunion Extraordinaire [Societe Geologique de France] dans
les Corbieres et les parties adjacentes des Pyrenees du Dimanche
11 au Lundi 19 Septembre, 1892. 8vo. Paris, 1892.
Carpenter, W. B. The Microscope and its revelations. Seventh
Edition, by the Rev. W. H. Daliingcr. 8vo. London, 1S91.
Purchased.
Carr, J. W. A Contribution to the Geology and Natural History
of Nottinghamshire. 8vo. Nottingham, 1893.
Castillo, Antonio del. See Maps. Mexico.
Chabas, F. Les Silex de Volgu (Saone-et- Loire). 4to. Chalon-sur-
Saone, 1874. Purchased.
. Les Silex de Volgu au Musee de Chalon-sur-Saone. 8vo.
Chalon-sur-Saone, 1874. Purchased.
. Les Fouilleurs de Solutre. 8vo. Chalon-sur-Saone, 1875.
Purchased.
. See Loriol, P. de, and Meray, C.
Chewings, C. Beitrage zur Kenntniss der Geologie Siid- und Central-
Australiens, nebst einer Uebersicht des Lake-Eyre Pteckens und
seiner Randgebirge. 8vo. Heidelberg, 1894.
Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 237
Choffat, P. Sec Portugal.
Clark, W. B. See United States and Williams, Q. H.
Clarke, F. W. See United States.
Claypole, E. The Cladodont Sharks of the Cleveland Shale. 8vo.
Minneapolis, 1893.
Collins, J. H. Illustrations of Cornish Fossils. 8vo. Penzance,
1894.
Congres Geologique International. Compte-Rendu do la 5me
Session, Washington. 8vo. Washington, 1893. Presented by
the Secretary, S. P. Emmons, Esq.
Conrad, T. A. See Harris, G. D.
, and W. H. Dall. Republication of [T. A.] Conrad's Fossils of
the Medial Tertiary of the United States, with Introduction by
W. H. Dall. 8vo. Philadelphia, 1893. Purchased.
Conwentz, H. See Sweden.
Cooke, G. H. See Maps. New Jersey.
Cope, E. D. See Texas.
Cotteau, G. Sec France. Paleontologie Francaisc.
Crawford, J. J. See California.
Credncr, H. Die geologische Landesuntersuchung des Konigreiches
Sacbsen. 8vo. Berlin, 1893.
. Zur Histologic der Faltenzahne palaozoischer Stcgocephalen.
8vo. Leipzig, 1893.
. Die Stegocephalen und Saurier aus dem Rothliegenden des
Plauen'schen Grundes bei Dresden. X. Theil. 8vo. Berlin, 1894.
Crosskey, H. W. Sec Lewis, H. Carvill.
Dall, W. H. Sec Conrad, T. A.
. See Periodicals. Washington. Smithsonian Institution.
. Sec United States.
Dall, W. H., and J. Stanley-Brown. Cenozoic Geology along the
Apalachicola River. 8vo. Rochester, N.Y., 1894.
Dallinger, W. H. See Carpenter, W. B.
Dames, W. Ueber das Vorkommen von Ichthyopterygiern im
Tithon Argentiniens. 8vo. Berlin, 1893.
. Ueber die Gliedcrung der Flotzfonnationen Helgolands.
8vo. Berlin, 1893.
. Ueber Zeuglodonten aus Aegypten und die Beziehungen der
Archaeocetcn zu den ubrigen Cetaceen. 4to. Jena, 1894.
1
238 ADDITIONS TO THE LIB BART. [NOV. 1 894,
Barton, N. H. See United States.
Dathe, E. Geologische Beschreibung der Umgebung von Salzbrunn.
(Festschrift zu dem V. Allgemeinen Deutschen Bergman nstag in
Breslau, 1892.) 8vo. Berlin, 1892. Presented by II. Bauerman,
Esq., F.O.S.
David, T. W. Edgeworth. See New South Wales.
Davis, W. M. Physical Geography in the University. 8vo.
Chicago, 1894.
Dawson, O. M. Geological Notes on some of the Coasts and Islands
of Bering Sea and vicinity. 8vo. Rochester, N.Y., 1894.
Dawson, Sir J. William. New Species of Cretaceous Plants from
Vancouver Island. 4to. Montreal, 1893.
. Some Salient Points in the Science of the Earth. Svo.
London, 1893.
. The Canadian Ice Age: being Notes on the Pleistocene
Geology of Canada, with especial reference to the Life of the
Period and its Climatal Conditions, and Lists of the Specimens in
the Museum. (Peter Redpath Museum, McGill University,
Montreal.) 8vo. Montreal, 1893.
. Some recent Discussions in Geology. 8vo. Rochester, NX,
1894.
Day, D. T. See United States.
De Geer, G. See Sweden.
Delafond, — . See Loriol, P. de.
Delebecque, A., et L. Dupare. Sur les changements survenus an
glacier de la Te*te Rousse depuis la catastrophe de Saint-Gervais,
du 12 juillet, 1892. 4to. Paris, 1893.
De*midoff, Anatole de. Voyage dans la Russie meridionale et Is
Crimeo, par la Hongrie, la Valachie et la Moldavie. Vol. ii.
Text, 8vo. ; Atlas, fol. Paris, 1842. Purchased.
. . . Vol. iv. Text, 8vo ; Atlas, fol. Paris, 1842.
Purchased.
Dent, H. C. A Year in Brazil. 8vo. London, 1886. Purchased.
Des Cloizeaux, A. Manuel de Mineralogie. Tome ii. Fasc
8vo. Paris, 1893. Purchased.
Desor, E. Aus Sahara und Atlas. 8vo. Wiesbaden, 1865.
Purchased.
Diener, C. Der Gebirgsbau der Westalpen. 8vo. Vienna, 1891.
Purchased.
Digitized by Google
Vol. 50.] ADDITIONS TO TUB LIBRARY. 239
Diller, J. S. Cretaceous and Early Tertiary of Northern California
and Oregon. 8vo. Rochester, N.Y., 1893.
. lie volution in the Topography of the Pacific Coast since the
Auriferous Gravel Period. 8vo. Chicago, 1894.
, and C. Schuchert. Discovery of Devonian Rocks in California.
Part I. 8vo. New Haven, Conn., 1894.
, and T. \V. Stanton. The Shasta-Chico Series. 8vo. Rochester,
N.Y., 1894.
Dollfus, O. F. Animaux Inferieurs. [Extrait de l'Annuaire
Geologique Universel, 1891.] 8vo. Paris, 1892-93.
. Bryozoaires. [Extrait de l'Annuaire Geologique Universel,
1891.] 8vo. Paris, 1892-93.
. Crostaces inferieurs. [Extrait de l'Annuaire Geologique
Universel, 1891.] 8vo. Paris, 1892-93.
. Quaternaire. [Extrait de l'Annuaire Geologique Universel,
1891.J 8vo. Paris, 1892-93.
. Considerations sur la limito sud du Bassin KouUler du Nord
do la Prance. 8vo. Iille, 1893.
. Recherches gcologiques sur les Environs do Vichy (Allier).
8vo. Paris, 1894.
. See Lippmann, E.
Drayson, A. W. Remarks by, on Mr. Warren Upham's paper,
read 4th June, 1894, at the Victoria Institute, London. 8vo.
London, 1894.
Drygalski, E. von. Ein typisches Fjordthal. (F. Fr. von Richt-
hofen. Fostschrift, 41.) 8vo. Berlin, 1893. Purchased.
Dublin Science and Art Museum. The Mineralogical, Geological,
and PalxBontological Collections in the. [Extraot from the
General Guide to the Museum.] 8vo. Dublin, 1893. Presented
by T. Leighton, Esq., F.Q.S.
Dumble, E. T. See Texas.
Dun, W. S. Set New South Wales.
Dunn, E. J. Glaciation of the Western Highlands, Tasmania. 8vo.
Melbourne, 1893.
. See Maps.
Duparc, L. Le Lac d'Annecy. 8vo. Geneva, 1894.
, et L. Mrazec. Sur l'extrdmite nord-est du Mont-Blanc. 4to.
Paris, 1893.
, — 1 — . Note sur les roches amphiboliques du Monfc-Blano.
8vo. Geneva, 1893.
, . Sur les eologites du Mont-Blanc. 4to. Paris, 1893.
24O ADDITIONS TO THE LIBBABT. [NOV. 1S94,
Duparc, L., et E. Hitter. Formation Quaternaire d'£boulis an
Mont Saleve. 8vo. Geneva, 1893.
, . Lea Massifs Cristallins de Beanfort et Cevins. 8vo.
Geneva, 1893.
, . Les Formations du Carbonifere et les Quartzites du
Trias dans la region N.-O. de la premiere zone Alpine. Etude
pdtrographique. 4to. Geneva, 1894.
, . Carbonifere Alpin. 8vo. Geneva, 1894.
. See DeUbecque, A.
Dusen, P. See Sweden.
Eck, H. See Baden.
Egger, J. O. Foraminiferen aus Meeresgmndproben, gelothet von
1874 bis 1876 von S.M.Sch. * Gazelle/ 4to. Munich, 1893.
Egypt. Ministry of Public Works. Report on Perennial Irrigation
and Flood Protection for Egypt, by W. Willcocks, with a note by
W. E. Garstin. 4to. Cairo, 1894. With Atlas.
Elicb, E. See Reiss, W.
Elliott, Sir C. A. See Periodicals. Calcutta. Asiatic Society of
Bengal.
England and Wales. See Great Britain.
Etheridge, R., Jun. See New South Wales.
. See South Australia.
, and R. L. Jack. Catalogue of Works, Papers, Reports, and
Maps on the Geology, Palaeontology, Mineralogy, Mining, and
Metallurgy, etc. of the Australian Continent and Tasmania. 8vo.
London, 1881. Purchased.
Ettingshausen, C. Freiherr von. Ueber fossile BanJcsxa-A rten una
ihre Beziehung zu den lebenden. 8vo. Vienna, 1890.
. Die fossile Flora von Schoenegg bei Wies in Steiennark.
I. und II. Theil. 4to. Vienna, 1890 & 1891.
. Ueber tertiare i^a^rti^Arten der siidlichen Hemisphare.
8vo. Vienna, 1891.
. Ueber fossile Pflanzenreste aus der Kreideformation Aus-
traliens. 8vo. Vienna, 1893.
. Ueber neue Pflanzenfossilen aus den Tertiarschichten Steier-
marks. 8vo. Vienna, 1893.
Everett, 0. See Illinois.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 24I
Favre, Ernest, et Hans Schardt. Revue Goologique Suisse pour
l'annee 1893. Tome xxiv. 8vo. Geneva, 1894.
Fedden, F. See India.
Feistmantel, 0. See India.
. See New South Wales.
Felix, J., und H. Lenk. Beitrage zur Geologic und Palaontologie
der Republik Mexico. II. Theil, Heft L 4to. Leipzig, 1893.
Purchased.
Fellenberg, E. von. See Switzerland.
Ferrier, W. F. Notes on the Microscopical Character of some
Hocks from the Counties of Quebec and Montmorency. 8vo.
Ottawa, 1893.
. See Canada.
Festenberg-Packisch, H. Die Entwickelung des Niederschlesischen
Steinkohlenbergbaues. (Den Theilnehmern am V. AUgemoinen
Deutschen Bergmannstage gewidmet, 1892.) 4to. Waldenburg,
1892. Presented by H. Bauerman, Esq., F.OJS.
Finland. Finlands Oeologiska Under sokning. Beskrifning till
. » >
Kartbladet Nos. 22, 23 & 24, af J. J. Sederholm och H. Berghell.
8vo. Helsingfors, 1892.
. See Maps.
Fischer, Hans. Ost-Asien. (F. Fr. von Richthofen, Festschrift,
363.) 8vo. Berlin, 1893. Purchased.
Fisher, 0. Rigidity not to bo relied upon in estimating the Earth's
Age. 8vo. New Haven, Conn., 1893.
. Densities in the Earth's Crust. 8vo. London, 1894.
Floyer, E. A. Etude sur le Nord-Etbai, entre le Nil et la Mer
Rouge. 8vo. Cairo, 1893.
Follman, 0. Die unterdevonische Schichten von Olkenbach. 8vo.
Bonn, 1882. Purchased.
Foster, C. Le Neve. See Great Britain.
Fox, Howard. The Making of Flints and Cherts. -8vo. Truro,
1894.
France. MinisUre des Travaux Publics. Etudes des Gites Mineraux
de la France. Bassin Houiller et Permien d'Autun et d'£pinac.
Fasc. iv. Flore Fossile. 2me Partie, par B. Renault. Atlas.
4to. Paris, 1893.
242
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
France. Miniature des Travaux Publios. Services de la Carte Geo-
logique de la France et des Topographies Souterraines. Bulletin.
Tome iii. 1891. No. 21. Les Chatnes subalpines entre Gap et
Digne, par E. Haug. 8vo. Paris, 1891. Purchased.
. . . . Tome iv. 1892-93. No. 34. Note
sur la geologic de la Haute Vallee d'Aspe, Basses -Pyrenees, par
J. Seunes. 8vo. Paris, 1893. Purchased.
. See Maps.
. Paleontologie Francaise, ou Description des Fossiles de la
France. lre 86*116. Animaux Fossiles. Livraisons 28-4£5.
Terrains Tertiaires. Eocene. Ecbinides, Tome ii., par G. Cot-
teau. 8vo. Paris, 1892-94. Purclxased.
. . 2* Serie. Vege*taux Fossiles. Livraison 47.
Terrain Jurassiqne. Types Proangiospermiqucs et Supplement
final, par G. de Saporta. 8vo. Paris, 1891.
Fraser, M. A. C. Western Australian Year-Book for 1892-93.
8vo. Perth, 1893. Presented by the Agent-Qeneral for Western
Australia.
Freeh, F. Die Tribulaungruppe am BrenDer in ihrer Bedeutung
fur den Gebirgsbau. (F. Fr. von Richthofen, Festschrift, 77.)
8vo. Berlin, 1893. Purchased.
Fredholm, K. A. See Sweden.
Fric, A. See Bohemia.
Fuchs, E., et L. de Launay. Traite des Gites Mineraux et Metalli-
feres. 2 vols. 8vo. Paris, 1893. Purchased.
Garstin, W. E. See Egypt.
Geer, G. de. See Sweden.
Geikie, Sir Archibald. Text-book of Geology. 8vo. London,
1893. Purchased.
Geikie, James. Fragments of Earth-Lore, Sketches and Addresses,
Geological and Geographical. 8vo. Edinburgh, 1893. Pur-
chased.
Georgia. Geological Survey. The Paleozoic Group. The Geology
of Ten Counties of North-western Georgia and Resources, by
J. W. Spencer, State Geologist. 8vo. Atlanta, Geo., 1893.
Geological Congress, International. See Congres.
Gibson, A. M. See Alabama.
Gilbert, O. K., and B. S. Lyman. The Name Newark » in
American Stratigraphy. 8vo. Chicago, 1894.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
243
Gilpin, E., Jun. Notes on an Occurrence of Manganese and Zino
Oro in Nova Scotia. 8vo. Halifax, N.S., 1893.
• . The Use of Safe Explosives in Mines. 8vo. (Can. Soc.
C.E.) 1893.
. See Nova Scotia.
Gobi, W. Geologisch-bergmannische Karten mit Profilen von
Jdria, nebst Bildern von den Quecksilber-Lagersttitten in Idria.
8vo. Vienna, 1894. Purdiased.
Gosselet, J. Gites de phosphate de chaux de Templeux-Belli court
et de Buire. 8vo. Lille, 1893.
. Gres a silex de Beuzeville. 8vo. Lille, 1 893.
. Les Collines do l'Artois. 8vo. Lille, 1893.
•. See Horion, C.
Graf, J. H. See Periodicals. Bern.
Grand'Eury, C. Geologic et Palcontologie du Bassin Houiller du
Gard. Text, 8vo ; Atlas, Fol. Saint-Etienne, 1890. Pur-
chased.
Graydon, G. On the Fish enclosed in Stone of Monte Bolca. 4to.
Dublin, 1794. Purchased.
Great Britain and Ireland. Geological Survey. Annual Report
by the Director General of the Geological Survey and Museum of
Practical Geology for the year ending December 31st, 1892. 8vo.
London, 1893.
Great Britain. Geological Survey. Memoirs. The Jurassic Rocks
of Britain. Vol. iii. The Lias of England and Wales (Yorkshire
excepted). By Horace B. Woodward. 8vo. London, 1893.
. . . . Vol. iv. The Lower Oolitic Rocks
of England (Yorkshire excepted). By Horace B. Woodward.
8vo. London, 1894. «
. . England and Wales. Memoirs. The Geology
of South- western Norfolk and Northern Cambridgeshire.
(Expiation of Sheet 65.) By W. Whitaker, S. B. J. Skertchlcy,
and A. J. Jukos-Browne. 8vo. London, 1893.
. . See Maps.
. Home Department. Minos. Reports, 1892. Summaries
of the Statistical Portion of the Reports of Her Majesty's
Inspectors of Mines. 4to. London, 1893. Presented by Prof. C.
Le Neve Foster, F.G.S.
and Ireland. Home Office. Mines. List of Mines worked
in the year 1893. 4to. London, 1894. Presented by Prof. C.
Le Neve Foster, F.G.S.
. . . List of Plans of abandoned Mines deposited
in the Home Office. Corrected to 31st December, 1893. 4to.
London, 1894. Presented by Prof. C. Le Neve Foster, F.GJS.
I
244 ADDITIONS TO THE LIBRARY. [NOV. 1 894,
Great Britain. Mines. Report of Arthur H. Stokes, Esq., H.M. In-
spector of Mines for the Midland District (No. 8), to Her Majesty's
Secretary of State, for the year 1892. 4to. London, 1893.
. Parliamentary Report of the Royal Commission appointed
to inquire into the Water Supply of the Metropolis. 4to.
London, 1893.
. . Minutes of Evidence. 4to. London, 1893.
. . Appendices to Minutes of Evidence. 4to. London,
1893.
. . General Index to the Report, Miuutes of Evidence,
and Appendices. 4to. London, 1893. Presented by Sir Henry
II. Howorth, F.G.S.
. . . . Purchased,
Greenland. Meddelelser om Grtfnland, udgivno af Commissionen
for Ledelsen af de gcologieke og geographiske Undersdgelser
i Gr0nland. Hefte 3. Fortsaettelse 3 & 4. 8vo. Copenhagen,
1892-94. Purchased.
-. . Hefte 7. 8vo. Copenhagen, 1893. Purchased.
Gregory, J. W. See India.
Greeley, W. S. Geological History of the Rawdon and the Boo-
thorpe Faults in the Leicestershire Coal-field. 8vo. Newcastle-
upon-Tyne, 1892.
Grieg, J. A. See Norwegian North-Atlantic Expedition.
Griesbach, G. L. See India.
Griswold, L. S. See Arkansas.
Gruner, E. Atlas du Comite Central des Houilleres de France.
Cartes des Bassins Houillers de la France, de la Grande-Bretagne,
do la Belgique et de l'Allemagne, accompagnees d'une Description
technique gencrale et de renseignements statistiques et com-
merciaux. Fol. Paris, 1893. Purchased.
Guettard, J. E. Memoires sur la Mincralogie du Dauphine. 2 vols.
4to. Paris, 1779. Purchased.
Gueymard, Emile. Sur la Min6ralogie, la Geologie et la Me'tallurgie
du Departement de Tlsere. 8vo. Grenoble, 1831. Purchased.
Giimbel, K. W. von. Geologie von Bayern. Band ii. Lief. 1-12.
8vo. Cassel, 1892-93. Purchased.
Guppy, R. J. Lechmere. The Microzoa of the Tertiary and other
Rocks of Trinidad and the West Indies. 8vo. Port-of-Spain.
1893.
Hack, Maria. Geological Sketches and Glimpses of the Ancient
Earth. 3rd Edition. 8vo. London, 1839. Purchased.
Digitized by Google
Vol.50.] ADDITIONS TO THE LIB RAM".
245
Hague, A. See United States.
Ha^.n,v^* „Zur wirtschaftlichen StelW dee Nepers (F PV ™
Richthofen, Festschrift, 371.) S^S^fSS
#arJ*r, ^Z/m£ Notes on North of England Rocks T TT fi„
Huddersfield, 1889 & 1890. n* 8vo'
— ^ Notes on the Physics of Motamorphism. 8vo. London,
"london? I88r ' °f Pyrite8 °ther Minerak iD Slate' 8to.
~Iondon° S! Thi°k^ °f Dyke8 and Bed8 * 8vo.
^^P?^0l05^al,NuOtO8 °n 60me Boulders from the Boulder-
Clays of East Yorkshire. 8vo. Halifax, 1889. ™"<"»-
"^o. B*J 189ClOUeCti0n °f R°Ck8 *™ ^ands.
-. On various Crystalline Rocks. 8v0. London, 1891.
^OStt^-SX RfcBJ5SR.- th0
"Tudd^MdS.1"™ °f th<! 8vo.
_^is,^9rmetam<>lplli9m 'm 18000,18 ^ 8to- Minnoa-
'uJSliSt7** ^ h Bflsi0 ^"us Rocks. 8vo.
"TondonSt Ge°l0gy " ^ °f th° ^»d0. 8vo.
— -a Some North-Country Quarbitee. 8vo. Huddersfield,
— .^TheUmprophyresef the North of England. 8vo. London,
1™. Son' ISuf ^ aPpHed 40 Conoentration.
— . a Extinetion-Angles in Cleavage Flakes. 8to. London,
w-^^ij^^ th° M0ta^- of
—.^ Norwegian Boulders in Holdernoss. 8vo. Huddersfield,
246 ADDITIONS TO THE LIBRARY. [Nov. 1 894.
Barker, Alfred. Tho Use of the Protractor in Field-Geology. 8vo.
Dublin, 1893.
Harle, E. Rcstes d' Elephants dn sud-ouest de la France. 8vo.
Toulouse, 1893.
. Succession de diverges faunes, a la fin du quaternaire, dan?
le sud-ouest de la France. 8vo. Toulouse, 1893.
. Decouverte d'ossements d'Hyenes rayees dans la grotte de
Montsaunes (Haute-Garonne.) 4to. Paris, 1894.
Harris, G. D. Republication of Conrad's Fossil Shells of the
Tertiary Formations of North America. 8vo. Washington,
1893. Purchased.
Harris, O. F. See Newton, R. Bullen,
Harrison, W. Jerome. On the Search for Coal in the South-east of
England ; with special Reference to the Probability of the
Existence of a Coal-field beneath Essex. 8vo. Birmingham.
1894.
Hart, Francis. Western Australia in 1893. 8vo. London, 1893.
Presented by the Agent- General for Westtrn Australia.
Hatch, F. H. Notes on the De Kaap Gold Fields, Transvaal
Republic. [Newspaper extract.] Johannesburg, 1894.
" Hauchs." Det Videnskabelige Udby tte af Kanonbaaden " Hauchs *
togter in de Danske Have Indenfor Skagen i Aarene 1883-56, red
C. O. J. Petersen. Text & Atlas. 4to. Copenhagen, 1893.
Haughton, Samuel. Set Johnston-Lavis, H. J.
Hausse, R. See Saxony.
Haynes, H. W. See G. F. Wright.
Hedstrom, H. See Sweden.
Hcer, 0. Untersuchungen iiber das Elima und die Vegetations-
verhaltnisso des Tertiurlandes. Fol. Winterthur, 1860. Pur-
chased.
Helm, 0. See India.
Hesse. Grossherzogliches Ministerium des Innem. Geologisehe
Landesanstalt zu Darmstadt. Abhandlungen. Band ii. Heft 1.
No. 3. Die Marmorlager von Auerbach an der Bcrgstrasse in
geologischer, mineralogischer und technischer Beziehung, von L
Hoffmann. 8vo. Darmstadt, 1894.
. . . . Band ii. Heft 2. Die Alten
Neckarbetten in der Rheinebene, von A. Mangold. 8vo. Darm-
stadt, 1892.
. . . See Periodicals. Darmstadt.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 247
Hettner, A. Regenverteilung, Pflanzendecke und Besiedelung dor
tropischen Anden. (F. Fr. von Richthofen, Festschrift, 197.)
8vo. Berlin, 1893. Purchased.
Hides, Henry. Further Proofs of the Pre-Cambrian Age of certain
Granitoid, Felsitic, and other Rocks in N.W. Pembrokeshire.
8vo. London, 1886.
. On the Ffynnon Beuno and Cao Gwyn Caves. 8vo. London,
1886.
. Results of recent Researches in some Bone-caves in North
Wales (Ffynnon Beuno and Cae Gwyn). 8vo. London, 1886.
. The Cambrian Rocks of North America. 8vo. London,
1887.
. The Faunas of the Ffynnon Beuno Caves and of tho Norfolk
Forest Bed. 8vo. London, 1887.
. La Geologie du Nord du Pays do Galles. 8vo. London,
1888.
. On tho Cao Gwyn Cave, North Wales. 8vo. London,
1888.
. Pro-historic Man in Britain. 8vo. Hertford, 1889.
. On Pre-Cambrian Rocks occurring as Fragments in the
Cambrian Conglomerates in Britain. 8vo. London, 1890.
. The Effects produced by Earth-movements on Pre-Cambrian
and Lower Palajozoic Rocks in some Sections in Wales and
Shropshire. 8vo. London, 1890.
. The Rocks of St. Davids. 8vo. London, 1890.
. On borne Recently Exposed Sections in the Glacial Deposits
at Hendon. 8vo. London, 1891.
— — . Excursion to Henley and Finchley. 8vo. London, 1892.
. Fauna of the Olenellus-Zone in Wales. 8vo. London,
1892.
. On the Discovery of Mammoth and other Remains in
Endsleigh Street, and on Sections exposed in Endsleigh Gardens,
Gordon Street, Gordon Square, and Tavistock Square, London.
8vo. Loudon, 1892.
. On the "Grampian Series" (Pre-Cambrian Rocks) of the
Central Highlands. 8vo. London, 1892.
. Some Examples of Folds and Faults in the Devonian Rocks
at and near llfracombe, North Devon. 8vo. London, 1893.
. The Pre-Cambrian Rocks of Wales. 8vo. London, 1893.
vol. l. t
248 jLDDITIOXS TO THE LJBBJLET. [Nov. I S94,
Hill, R. T. Clay-materials of the United States. 8vo. Washington,
1893.
. Palaeontology of the Cretaceous Formations of Texas. — The
Invertebrate Palaeontology of the Trinity Division. 8vo. Wash-
ington, 1893.
. The Invertebrate Fossils of the Capri na-Limestone Beds.
8vo. Washington, lb93.
. The Palaeontology of the Cretaceous Formations of Texas.
8vo. Washington, 1893.
Hise, C. R. van. See United States.
Hoffman, G. C. See Canada.
Hoffmann, L. See Hesse.
Hogben, G. Notes on the Earthquake of the 24th June, 1891.
8vo. Wellington, 1892.
. The Earthquake of the 4th December, 1891, with Notes
thereon. 8vo. Wellington, 1893.
. Australasian Association for the Advancement of Science.
Report of the Committee (No. 1). Seismological Phenomena in
Australasia. G. Hogben, Secretary. 8vo. Hobart, 1892.
Hogbom, A. G. See Sweden.
Holden, E. S. See United States.
Holland, T. H. See India.
Holm, G. See Sweden.
Hoist, N. 0. See Sweden.
Hopkins, T. C. See Arkansas.
Uorion, C, tt J. Gosselet. Lee Calcaires de Vise. 1™ Partie.
Etude Stratigraphique. 8vo. Lille, 1892.
Houorth, Sir Henry H. The Glacial Nightmare and the Flood.
2 vols. 8vo. London, 1893.
Hughes, Herbert W. A Text-book of Coal-Mining, for the use of
Colliery Managers and others. 8vo. London, 1892. Presented
by H. Bauerman, Esq., F.G.S.
Hull, E. The Coal-fields of Great Britain. 8vo. London, 1861.
Purchased.
Hull, E. The Great Submergence. 8vo. Leeds, 1893.
Hume, W. F. Chemical and Micro-mineralogical Researches on the
Upper Cretaceous Zones of the South of England. 8vo. London,
1893.
. The Genesis of the Chalk. 8vo. London, 1894.
by Googl
Vol. 50.]
ADDITIONS TO THE LIBRARY
249
Hutchinson, H. N, Creatures of other Days. 8vo. London, 1894.
Illinois Geological Survey. (A. H. Worthen, Director.) Vol. vii.
Geology and Palaeontology. Geology, by A. H. Worthen. Paloe-
ontology, by A. H. Worthen, 0. St. John, S. A. Miller, C. Wachs-
muth, and W. H. Barris. 8vo. Springfield, 111. 1883. Pur-
chased,
. . ( .) VoL viii. Geology and Palaeontology.
Edited by Joshua Lindahl, State Geologist. Geology, by A. H.
Worthen. Palaeontology, by A. H. Worthen, C. Wachsmuth,
F. Springer, E. 0. Ulrich, and 0. Everett. Text and Plates.
8vo. Springfield, 111. 1S90. Purchased.
. . See Periodicals. Springfield, 111. Illinois State
Museum of Natural History.
India. Geological Survey. A Manual of the Geology of India.
Stratigraphical and Structural Geology. Second Edition, revised
and largely rewritten by It. D. Oldham. 8vo. Calcutta. 1893.
. ■. . Presented by R. D. Oldliam, Esq., F.OJS.
. . Memoirs. Palaeontologia Indica. Series ix. The
Jurassic Fauna of Cutch. Vol. ii. Part 1. The Echinoidea of
Cutch, by J. W. Gregory. 4to. Calcutta, 1893.
. . Records. Vol. xxvi. Parts 2-4. 1893.
G. L. Griesbach. Notes on the Earthquake in Baluchistan on the
20th December, 1892, 57.— P. Helm. Further Note on Burmite, a
new amber-like fossil resin from Upper Burma, 61. — R. D. Oldham.
Note on the Alluvial Deposits and Subterranean Water-supply of
Rangoon, 64. — T. D. la Touche. Geology' of the Sherani Hills, 77. —
F. Noetling. Carboniferous Fossils from Tenasserim, 96. — R. D.
Oldham. On a deep Boring at Chandernagore, 100. — P. N. Bose.
Note on Granite in tne districts of Tavoy and Mergui, 102. — C. L.
Griesbach. On the Geology of the country between the Chappar
Rift and Harnai in Baluchistan, 113. — P. N. Bose. Notes on the
Geology of a part of the Tenasserim Valley, with special reference
to the Tendau-Kamapying Coal-field, 148. — T. H. Holland. On a
Magnetite from the Madras Presidency containing Manganese and
Alumina, 164.— T. H. Holland. On Hislopite, 166.
. . . Vol. xxvii. Part 1. 1894.
T. D. la Touche. Report on the Bhaganwala Coal-field, Salt
Range, Punjab, 16.
— . — . Indian Museum, Calcutta. Popular Guide to the
Geological Collections. No. 1. Tertiary Vertebrate Animals, by
R. Lydekker. 8vo. Calcutta, 1879.
. . . . No. 2. Minerals, by F. R. Mallet.
8vo. Calcutta, 1879.
. . . . No. 3, Meteorites, by F. Fedden.
8vo. Calcutta, 1880.
t2
250 ADDITIONS TO THE LIBRABT. [Nov. 1894,
India. Geological Survey. Indian Museum, Calcutta. Popular !
Guide to the Geological Collections. No. 4. Palaeontological
Collections, by 0. Fcistmantel. Svo. Calcutta, 1881. '
. . . . No. 5. Economic Mineral Products, |
by F. R. Mallet. 8vo. Calcutta, 1883.
International Geological Congress. See Congres.
Ireland, W., Jun. See California.
Issel, A. Liguria, Geologica e Preistorica. Vols, i., ii., and Atlas.
8vo. Genoa, 1892. Purchased.
Jaccard, A. See Switzerland.
Jack,, R. L. Report on Mount Morgan Gold Deposits. (Reprint.)
4to. Brisbane, 1893.
. See Etheridge, R., Jun.
. See Queensland and Maps : Queensland.
Jaekel, 0. Die eociinen Solachier vom Monte Bolca. Ein Beitrag
zur Morphogenie der Wirbelthiere. 8vo. Berlin, 1894. Pur-
chased.
Japan. Imperial Geological Survey. Report on the, with a cata-
logue of articles exhibited by the Geological Survey at the World's
Columbian Exposition. 8vo. Tokyo, 1893.
Jeans, J. S. See Periodicals. London. Iron and Steel Institute.
■
Jelly, E. C. A Synonymic Catalogue of the Recent Marine Bryo-
zoa, including Fossil Synonyms. 8vo. London, 1889. Pur-
chased.
Jentzschf A. Bericht iiber die Verwaltung des Provinzialmuseums
im Jahre 1892. 4to. Konigsberg in Pr., 1892.
Johnston, Ii. M. Reference List of various Books and Memoirs on
Scientific, Social, and Economic Subjects [on Tasmania], written
and published since the year 1873. 8vo. Hobart, 1893.
. The Glacial Epoch of Australia. 8vo. Hobart-, 1893.
Johnston -Lav is, H. J. Monograph of the Earthquakes of Ischia,
a memoir dealing with the Seismic Disturbances in that Island
from remotest times, with special observations of those of 1881
and 1883 ; and some calculations by the Rev. Prof. Samuel
Haughton. 4to. London & Naples, 1885. Purchased.
Johnston-Lavis, II. J. II Pozzo ArtesiaDO di Ponticelli, 1886.
4to. Naples. 1889.
. Notes on the Ponza Islands. 8vo. London, 1889.
Vol. 50.]
ADDITIONS TO THE LIBRARY".
Johnston-Lavis, H. J. On a Remarkable Sodalite Trachyte lately
discovered in Naples, Italy. 8vo. London, 1889.
. Report of the [British Association] Committee appointed
for the investigation of the Volcanic Phenomena of Vesuvius and
its neighbourhood. 8vo. London, 1890.
. . . 1893.
. Notes on the Pipernoid Structure of Igneous Rocks. 8vo.
London, 1893.
. Osservazioni geologiche lungo il tracciato del grand' Emis-
sario-Fognone di Napoli dalla Pietra sino a Pozzuoli. 8vo.
Rome, 1890.
. Volcans et Tremblements de Terre. 8vo. Paris, 1889.
. . . 1890.
. Fifty conclusions relating to the Eruptive Phenomena of
Monte Somma, Vesuvius, and Volcanic Action in general. 8vo.
Naples, 1890.
. Su una Roccia continente Leucite trovata sulT Etna. 8vo.
Acireale, 1889.
. The Extension of the Mellard Reade and C. Davison Theory
of Secular Straining of the Earth to the Explanation of the Deep
Phenomena of Volcanic Action. 8vo. London, 1890.
. The State of the Active Sicilian Volcanoes in September
1889. 8vo. Edinburgh, 1890.
Jones, Daniel. The Structure of the Forest of Wyre Coalfield.
8vo. Newcastle-upon-Tyne, 1894.
Jones, T. Rupert. Note on a Fossil Cypridinad from the South of
the Lleyn. 8vo. London, 1893.
. Mr. T. C. J. Bain, of the Cape Colony. 8vo. London,
1894.
. On some Fossil Ostracoda from S.W. Wyoming and from
Utah, U.S.A. 8vo. London, 1893.
. The Fossil Phyllopoda of the Palooozoic Rocks. — Tenth
Report of the Committee [British Association, Section CJ, con-
sisting of Professor T. Wiltshire, Dr. Henry Woodward, and
Professor T. Rupert Jones (Secretary). 8vo. London, 1893.
. On the Rhajtic and some Liassic Ostracoda of Britain. 8vo.
London, 1894.
— , et J. W. Kirl-by. Sur uno Leperditia nouvelle, du calcaire
carbonifere de la Belgique. 8vo. liege, 1893.
252 ADDITIONS TO THE LIBRARY. [NOV. 1894,
Jones, T. Rupert, and Henry Woodward. On some Palaeozoic
Phyllopodous and other Fossils. 8vo. London, 1893.
, . The Fossil Phyllopoda of the Palaeozoic Rocks. 8m
London, 1893.
Jbnsson, J. See Sweden.
Jukes-Browne, A. J. The Geographical Evolution of the North Sea.
8vo. London, 1893.
Jukes-Browne, A. J. See Great Britain.
Earpinsky, A. See Russia and Maps : Russia.
Karrer, F. Geologische Studien in den tertiaren und jiingeren
Bildungen des Wiener Beckens. 8vo. Vienna, 1893.
Kayser, E. Lehrbuch der Geologic. Erster TheiL AHgcmeine
Geologie. 8vo. Stuttgart, 1893.
Kellgren, A. G. See Sweden.
Kemp, J. F. The Ore Deposits of the United States. 8vo. New
York, 1893. Purchased.
Kendall, J. D. The Iron Ores of Great Britain and Ireland. 8vo.
London, 1893. Purchased.
Kilian, W. See Spain.
Kirl-by, J. W. See Jones, T. Rupert.
Klautzsch, A. See Reiss, W.
Klemm, G. See Hesse.
Knowlton, F. H. See United States.
. See Periodicals. Washington. Smithsonian Institution.
Koken, E. Die Vorwelt und ihro Entwickelungsgeschichte. 8vo.
Leipzig, 1893. Purchased.
Koenen, A. von. Das Norddeutsche Unter-Oligocan und seine Mol-
lusken-Fauna. Lief. v. & vi. 8vo. BerHn, 1893 & 1894.
Kretschmar, K. Die Kosmographie des Petrus Candidus Decem-
brius (F. Fr. von Richthofen, Festschrift, 267). 8vo. Berlin,
1893. Purchased.
Krustschoff, K. von. Ueber holokrystalline makrovariolithische
Gesteine. 4to. St. Petersburg, 1894.
Kurtz, F. Eine neue Nymphoeacca aus dem unteren Miocan von
Sieblos in der Rhon. 8vo. Berlin, 1894.
. Ueber Pflanzen aus dem norddeutschen Diluvium. 8vo.
Berlin, 1894.
Lablanne, L. Sur les terrains d'une partie de a vallee du Donetz.
8vo. Paris, 1839. Purchased.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 253
Langsdorff, W. Ueber don Zusammenhang der Gangsystome von
Clausthal und St. Andreasberg. 8vo. Clausthal, 1884. Pur-
chased.
. Gang- und Schist en-St udien aus dom wostliohen Oberharz.
8vo. Clausthal, 1885. Purchased.
Lapjxirent, A. de. Les Causes de l'Ancienno Extension des
Glaciers. 8vo. Brussels, 1893.
. Traite de Geologie. Troisieme Edition. Partie 1™ et 2me.
8vo. Paris, 1893.
. . . Deuxieme Partie. Geologie proprement
dite. Fasc. 5. 8vo. Paris, 1893. Purchased.
La Toucho, T. D. See India.
Launay, L. do. See Fuchs, E.
Lawson, A. C. See Minnesota.
Leigh, W. 8. See New South Wales.
Lent, C. See Baden.
Lepsius, Richard. Geologie von Attika. Ein Beitrag zur Lehre
von Metamorphismus der Gesteine. 4to. Berlin, 1893. Pur-
chased.
. . See Maps : Attica.
. Geologie von Deutschland und den angrenzenden Gebieten.
Band i. Lief. 3. 8vo. Stuttgart, 1892. Purchased.
Lesquereux, Leo. See United States.
Lesslin, Adolphe. Liste des Mineraux efc des Roches de la Vallee
de Liepvre (Canton do Sainte-Marie-aux-Mines). 8vo. Colmar,
1865. Purchased.
Lewis, H. Carvill. Papers and Notes on the Glacial Geology of
Great Britain and Ireland. Edited from his unpublished MSS.
with an Introduction by H. W. Crosskey. 8vo. London, 1894.
Presented by Mrs. Carvill Lewis.
Libert, — , ot Miciol, — . Cataloguo Mineralogique et Pdtrologique
du Finistere. 8vo. Morlaix, 1885. Purchased.
iindahl, J. See Illinois.
Linne, Carl von. See Periodicals &c. Stockholm.
Lippmann, E., et G. F. Dollfus. Un forago a Divers (Calvados).
8vo. Paris, 1893.
Liversidge, A. On the Origin of Moss Gold. 8vo. Sydney, 1893.
. On the Condition of Gold in Quartz and Calcite Veins.
8vo. Sydney, 1893.
254 ADDITIONS TO THE LIBRA BT. [Nov. 1 894,
IAversidge, A. On the Origin of Gold Nuggets. 8vo. Sydner,
1893.
. On the Crystallization of Gold in Hexagonal Forms. 8to-
Sydney, 1893. "
. Gold Moire*-Metallique. 8vo. Sydney, 1893.
. A combination Laboratory Lamp, Retort, and Filter Stand.
8vo. Sydney, 1893.
Lobley, J. Logan. The Genesis of Gold. 8vo. London, 1893.
Lodin, M. Etude sur les Gites Metalliferes de Pontgibaud. 8vo.
Paris, 1892. Purchased.
Loewinson-Lessing, F. Petrographisches Lexikon. I. Theil. 8vo.
Jurjew (Dorpat), 1893. Purchased.
Loriol, P. de. Notice sur le Pentacrinus de Sennecey-le-Grand ;
avec un Travail sur la Couche Calcaire qui le contient par if. Dela-
fond, et un Preambule par F. Chabas. 8vo. Chalon-sur-Saone,
1878. Purchased.
Lobs en, K. A. See Maps.
Lundbohm, H. See Sweden.
Lydekker, R. See India.
Lyman, B. S. See Gilbert, G. K.
. Age of the Newark Brownstone. 8vo. Philadelphia, 1894.
. The Great Mesozoic Fault in New Jersey. 8vo. Phila-
delphia, 1894.
Maitland, A. G. See Maps : Queensland.
Mallet, F. R. See India.
Mangles, H. A. See Monckton, H. W.
Mangold, A. See Hesse.
Mantell, G. A. Medals of Creation ; or First Lessons in Geology
and in the Study of Organic Remains. 1st edition. 2 vols.
8vo. London, 1844. Purchased.
Marcou, Jules. Lettres sur les Roches du Jura ot leur distribution
geographique dans les deux hemispheres. 8vo. Paris, 1860.
PurcJiased.
Marck, W. von der. Die Diluvial- und Alluvial- Ablagerungen im
Innern des Kreidebeckens von Munster. 8vo. Bonn, 1858.
Purchased.
Marsh, 0. C. Notes on Mesozoic Vertebrate Fossils. 8vo. New
Haven, Conn., 1892.
Digitized by
Vol. 50.]
ADDITIONS TO THE LIBRARY
255
Jtfarsh, 0. C. Description of Miocene Mammalia. 8vo. New
Haven, Conn., 1893.
. Restoration of Coryphodon. 8vo. New Haven, Conn.,
1893.
. Restoration of Camptosaurus. 8vo. New Haven, Conn.,
1894.
. Restoration of Elotherium. 8vo. New Haven, Conn., 1894.
Maryland State Weather Service. See United States Department
of Agriculture, Weather Bureau.
Melt, R. Sulla presensa dell' Iherus (subsect. Murelld) Signatus,
Fer. (Helicopena), nei Monti Ernici e nei dintorni di Terracina in
Provincia di Roma. 8vo. Siena, 1894.
Meray, C. Compte-rendu des Fouilles de la Caverne do Germolles ;
et Notes Additionnelles par F. Chabas. 4to. Chalon-sur-Saone,
1876. PurcJiased.
Micfiel-Levy, A. £tude sur la determination des Feldspaths dans
les Plaques Minces au point de vuc de la Classification des Roches.
8vo. Paris, 1894.
Miciol, — . See Libert, — .
Mikhalsky, A. See Russia and Maps : Russia.
Millar, C. C. B. Florida, South Carolina, and Canadian Phos-
phates ; giving a complete account of their occurrence, methods
and cost of production, quantities raised, and commercial import-
ance. 8vo. London, 1892.
Miller, S. A. See Illinois.
Milne-Edwards, A. See * Travailleur.'
Mingaye, J. C. H. See New South Wales.
Minnesota. Geological and Natural History Survey. (N. H,
Winchell, State Geologist.) Bulletin No. 8. I. The Anortho-
sytes of the Minnesota Coast of Lake Superior. II. The Laccolitio
Sills of the North-west Coast of Lako Superior. By A. C. Law-
son. With a prefatory note on the Norian of the North-west, by
N. H. Winchell. 8vo. Minneapolis, 1893.
Moberg, J. C. See Sweden.
Moesch, C. See Switzerland.
MojsUovics von Mojsvdr, E. Das Gebirge um Hallstatt. I. Abth.
Die Cephalopoden der Hallstatter Kalke. II. Hiilfte. 4to.
Vienna, 1893. Text and Atlas.
— — . Faunistische Ergebnisse aus der Untersuchung der
Ammoneen-Faunen der Meditcrranen Trias. 8vo. Vienna,
1893. Presented by J. W. Uulke, Esq., For.Sec.Q.S.
256 ADDITIONS TO THE LIBRARY. [Nov. 1 894,
Monclcton, Horace W. Geological Notes in the Neighbourhood of
Ongar, Essex. 8vo. Buckhurst Hill, 1893.
. On the Gravels near Barking side, Wanstead and Walt h am -
stow, Essex. 8vo. Buckhurst Hill, 1893.
. On the Occurrence of Boulders and Pebbles from the Glacial
Drift in Gravels south of the Thames. 8vo. London, 1893.
. Short Papers. 8vo. Edinburgh, 1893.
, und H. A. Mangles. Excursion to Faraham. 8vo. London,
1893.
Norton, G. If. Museums of the Past, the Present, and the Future,
particularly thoBe of Liverpool. 8vo. Liverpool, 1894.
Mrazec, L. See Duparc, L.
Miiller, C. F. L. R. Uebcr eioige menschliche Ueberreste aus der
Steinperiode. 8vo. Marburg, 1894. Purchased.
Munby, A. E. Notes on Polarized Light. 8vo. Newcastle-upon-
Tyne, 1894.
Naihorst, A. Q. Om en fossilforande leraflagring vid Skattmanad i
Upland. 8vo. Stockholm, 1893.
. Om orsakerna till det stora jordskalfvet i mellersta Japan
1891. 8vo. Stockholm, 1894.
. Ueber die palaeozoische Flora der arktischen Zone. 8vo.
Vienna, 1894.
. Zur fossilen Flora der Polarlaudor. Erster Theil. Erete
Lieferuog : Zur palaoroischen Flora der arktischen Zone. 4to.
Stockholm, 1894.
Nehring, A. Ueber Tundren und Steppen der Jetzt- und Vorxeit,
mit besonderer Beriicksichtigung ihrer Fauna. 8vo. Berlin,
1890. Purchased.
New South Wales. Australian Museum. Report of Trustees for
the year 1892. 4to. Sydney, 1893.
. Department of Lands. Thirteenth Annual Report, being
for the year 1892. 4to. Sydney, 1893. Presented by the
Afj ent- General for New South Wales.
. Department of Mines and Ayriadture. Annual Report for
the year 1891. 4to. Sydney, 1892.
— . . Annual Report for the year 1892. 4to. Sydney,
1893.
. .. Annual Report for tho year 1893. 4to. Sydney,
1894.
Digitized by Google
Vol. 50.]
ADDITIONS TO THE LIBRARY.
257
a New South Wales. Department of Mines and Agriculture. Geolo-
gical Survey. Memoirs. Palaeontology. No. 3. Geological
and Paheontological Iterations of the Coal and Plant-bearing Beds
of Palaeozoic and Mesozoic Age in Eastern Australia and Tas-
mania ; with special reference to the Fossil Flora. By 0.
Feistmantel. 4to. Sydney, 1890.
— . . . . . No. 4. The Fossil Fishes
of the Hawkesbury Series at Gosford. By A. Smith Woodward.
4to. Sydney, 1890.
— . . . . . No. 5. Parts 1 & 2. A
Monograph of the Carboniferous and Permo-Carboniferous Inver-
tebrate of New South Wales. By R. Etheridge, Jun. 4to.
Sydney, 1891 & 1892.
— . . . . . No. 7. The Mesozoic and
Tertiary Insects of New South Wales. By R. Etheridge, Jun.,
and A. S. Olliff. 4to. Sydney, 1890.
— . . . . . No. 8. Parts 1 & 2. Con-
tributions to a Catalogue of Works, Reports, and Papers on the
Anthropology, Ethnology, and Geological History of the Austra-
lian and Tasmanian Aborigines. By R. Etheridge, Jun. 4to.
Sydney, 1890.
— . . . Records. Vol. ii. Parts 1-4. 1890-92.
T. W. Edgeworth David. Proposed Petrological Classification
of the Rocks of New South Wales, 1. — R. Etheridge, Jun. On the
Occurrence of the Genus Tryplasma, Lonsdale (= PhoHdophyUum,
Lindstrbm), and another Coral apparently referable to Diphyphyllum,
Lonsdale, in the Upper Silurian and Devonian rocks of New South
Wales respectively, 15. — W. Anderson. Notes on the Tertiary Deep
Lead at Tumbarutnba, 21. — R. Etheridge, Jun. Note on Dromomts
aitxtralis, Owen, 36. — T. W. Edgeworth David and R. Etheridge,
Jun. The Raised Beaches of the Hunter River Delta, 37. — W.
Anderson. Notes on the Shell-heaps, or Kitchen-middens, accu-
mulated bv the Aborigines of the Southern Coastal District, 52. —
R. Etheridge, Jun. On some beautifully formed Stone Spearheads
from Kimberley, North-west Australia, 61. — G. A. Stonier. Notes
on the Gunnedal Coal-field, 06. — R. Etheridge, Jun. Note on the
Occurrence of Fish Remains in the Rocks of tne Drummond Range,
Central Queensland, 71. — W. Anderson. Descriptions of some Stone
W eapons and Implements used by the Aborigines of N.S. Wales, 73.
— 11: Etheridge, Jun. Description of Two U ndescribed Univalves
from the Lower Carboniferous Rocks of New South Wales, 82. —
T. W. Edgeworth David and W. Anderson. Notes on a Collection
of Rock* and Minerals from Mount Morgan, near Rockhampton,
Queensland, collected by and with Introduction by C. S. Wilkinson,
85. — J. C. II. Mingaye. Laboratory Notes on some New South
Wales Minerals, 93. — R. Etheridge, Jun. On the Occurrence of
Microscopic Fungi, allied to the Genus Palaachlya, Duncan, in the
Permo-Carboniferous Rocks of New South Wales and Queensland,
95. — T. W. Edgeworth David. The Associated Minerals and Vola-
tility of Gold, 100.— J. C. II. Mingaye. Analysis of samples of Coal
and Coke, manufactured from the various Coke-producing Coals in
the Northern, Southern, and Western Coal Districts of New South
WTales, 109.— T. W. Edgeworth David. Note on Mr. J. C. H.
<
»$8
ADDITIONS TO THE LIBRARY.
[Nov. 1894,
Mingaye's Analysis of New South Wales Coals and Coke, 117. —
R. Etheridge, Jim. Lepidodendron amtrale, McCoy : its Synonyms
and Range in Eastern Australia, 119. — W. Anderson. On the
General Geology of the South Coast, with Petrological Notes on
the Intrusive Granites and their Associated Rocks, around Moruva,
Mount Dromedary, and Cobargo, 141. — R. Etheridge, Jun. de-
scriptions of Four Madreporaria Rugosa: Species of the Genera
PhiUipMttrtta, Heliophyllum, and Cyathophylium, from the Palaeo-
zoic Rocks of New South Wales, 174.
New South Wales. Department of Mines and Agriculture. Geolo-
gical Survey. Records. Vol. iii. Parts 2-4. 1892 & 1893.
E. F. Pittnian. On the Geological Occurrence of the Broken
Hill Ore-deposits, 45. — R. Etheridge, Jun. The Pentameridsa of
New South Wales, 49. — G. A. Stonier. Geological Notes on the
Swamp Oak and Niancala Gold-fields, 60. — R. Etheridge, Jun.
Report on a Visit to the Narrangullen, or Cavan Cave, Taemas,
Murrumbidgee River, 68. — G. A. Stonier. On the Occurrence of
Leucite-Basalt at Lake Cudgellico (Cargelligo), 71. — R. Etheridge,
Jun. On the Occurrence of a Plant allied to Schizoneura, in the
Hawke8bury Sandstone, 74. — W. S. Leigh. Notes on the Rose-
brook Caves, near Cooma, 77. — R. Etheridge, Jun., and W. S. Dun.
The Australian Geological Record for the vear 1891, 86. — G. W.
Card. On a Sand from Bingera, 111. — R. Eftheridge, Jun. On the
Occurrence of Trigonia semiundulata, McCoy, in New South Wales,
and its significance, 116. — G. A. Stonier. On the Occurrence of
Basalt-glass (Tachylvte) at Bulladelah, 118.— W. S. Dun. On Palatal
Remains of Palorcnestes Azael, Owen, from the Wellington Caves
Bone-deposit, 120. — G. W. Card. Mineralogical and Petrological
Notes, 124. — R. Etheridge, Jun., and W. S. Dun. The Australian
Geological Record for the year 1892, with Addenda for the year
1891, 132.— W. S. Dun. A Locality Index to the Reports of" the
Geological Survev of New South Wales, from 1875 to 1892 inclu-
sive, 154. — T. W. E. David and E. F. Pittman. On the Occurrence
of Lrpidodendron australe(?) in the Devonian Rocks of New South
Wales, 194. — G. W. Card. On Celestine from the Neighbourhood of
Bourke, 201.
. Department of Public Works. Report for the year 1892.
4to. Sydney, 1893.
Newton, E. T. On some New Reptiles from the Elgin Sandstone.
4to. London, 1893.
. Reptiles from the Elgin Sandstone : Description of Two
New Genera. 8vo. London, 1893.
. The Vertebrate Fauna collected by Mr. Lewis Abbott from
the Fissure near Ightham, Kent. Svo. London, 1894. (See
Abbott, W. J. L.)
Newton, R. Bullcn, and G. F. Harris. A Revision of the British
Eocene Cephalopoda. Svo. London, 1894.
, . A Revision of the British Eocene Scaphopoda, with
Descriptions of some New Species. 8vo. London, 1894.
, . Descriptions of some new or little-known Shells of
Pulmonate Mollusca from the Oligocene and Eocene Formations
of England. Svo. London, 1894.
»
Tol. 50.] ADDITIONS TO TILE LIBRARY. 259
INew Zealand. Colonial Museum and Geological Survey. Twenty-
seventh Annual Report on the Colonial Museum and Laboratory.
1891-92. 8vo. Wellington, N.Z., 1893.
. Mines Department. The Mines Statement (1893) by the
Hon. R. J. Seddon, Minister of Mine*, and Report on the Gold-
fields of New Zealand. 4to. Wellington, 1893.
tfikitin, 8. See Russia and Maps : Russia.
Noetling, F. See India.
Xdggerath, J. Ueber aufrecht im Gcbirgsgestein eingeschlossenc
fossile Baumstiimme und andere Vegetabilien. 8vo. Bonn, 1819.
Purchased.
Nordenskjold, 0. See Sweden.
Norwegian North-Atlantic Expedition. (Den Norske Nordhavs-Ex-
pedition.) 1870-78. xxii. Zoologi, Ophiuroidea. Ved J. A.
Grieg. 4to. Christiania, 1893. Presented hy the Editorial Com-
Nottingham (British Association Meeting). See Carr, J. W., and
Allen, R.
Nova 8cotia. Department of Mines. (E. Oilpin, Esq., F.Q.S.,
Inspector of Mines.) Report for the nine months ending Sep-
tember 30, 1893. 8vo. Halifax, N.S., 1894.
Oldham, H. Y. The discovery of the Cape Verde Islands. (F. Fr.
von Richthofen, Festschrift, 181.) 8vo. Berlin, 1893. Pur-
cJuised.
Oldham, X. D. A Manual of the Geology of India. Stratigra-
phical and Structural Geology. Second Edition. 8vo. Calcutta,
1893.
. The Evolution of Indian Geography. 8vo. London, 1894.
The River Valleys of the Himalayas. 8vo. Manchester,
1894.
See India.
OUiff, A. 8. See New South Wales.
Omboni, Q. Discorso di apertura della Riunione nel Vicentino della
SocietA Geologica Italiana nel settembre 1892. 8vo. Rome,
1893.
Ordonez, E. See Aguilera, J. 0., and Maps : Mexico.
Osann, A, See Baden.
f'age, D. Economic Geology, or Geology in its relations to the
^rts and Manufactures. 8vo. Edinburgh, 1874. l\irchased.
V
Digitized by Google
26o ADDITIONS TO THE LIBRABY. [NOV. I 894,
Palacios, P. See Spain.
Palmberg, T. See Sweden.
Pamely, Caleb. The Colliery Manager's Handbook. 8vo. London,
1891. Presented by H. Bauerman, Esq., F.O.S.
Parent, H. Sur Pexistence du Gault entre lea Ardennes et le Bas-
Bonlonnais. 8vo. Lille, 1893.
. Sur une nouvelle espece d* Ammonite du Gault. 8vo. Lille,
1893.
. Notes sur lea Terrains Tertiaires du Pays de Caux. 8vo.
Lille, 1894.
Parona, C. F. Studio Monograflco della Fauna Raibliana di Lom-
bardia. 8vo. Pavia, 1889. Purchased.
Payot, Venance. Geologie et Mineralogie des environs du Mont-
Blanc. 8vo. Geneva, 1873. Purchased.
Pennington, R. Notes on the Barrows and Bone-caves of Derby-
shire. 8vo. London, 1877. Purchased.
Penrose, Jun., R. A. F. See Arkansas.
Perak Museum. See Wray, L., Jun.
Perrier, E. See < Travailleur.'
Peter, Bruno. See Reiss, W.
Peterson, C. G. J. See " Hauchs."
Philippson, A. Ueber die Typen der Kustenformen, insbesondere
der Schwemmlandskiisten. (F. Fr. von Richthofen, Festschrift,
1.) 8vo. Berlin, 1893. Purchased.
Pilling, J. C. See Periodicals : Washington.
Pittman, E. F. See New South Wales ; and Maps. New South
Wales.
Platz, Ph. See Baden.
Pdhlmann, R. See Steffen, H.
Poole, H. S. The Pictou Coal-Field ; a Geological Revision. 8vo.
Halifax, N.S., 1893.
Portugal. Direction des Travaux Oeologiques du Portugal. De-
scription de la Faune Jurassique du Portugal. Classe des Cepha-
lopodes par Paul Choffat. Premiere se'rie: Ammonites du
Lusitanien de la Contree de Torres- Vedras. 8vo. Lisbon, 1893.
Powell, J. W. See Periodicals : Washington.
Power, F. Banners. The Classification of Valuable Mineral Deposits.
8vo. Melbourne?, 1892.
Digitized by Google
Vol. 50.] ADDITIONS TO THE LIBRARY. 26 1
PreUer, 0. S. Du Richc. On the Origin of the Engadine Lakes.
8vo. London, 1893.
. On the Three Glaciations in Switzerland. 8vo. London,
1894.
Prestwich, J. On the evidences of a Submergence of Western
Europe, and of the Mediterranean Coasts, at the close of the
Glacial or so-called Post^Glacial Period, and immediately pre-
ceding the Neolithic or Recent Period. 4to. London, 1893.
Prussia. Kaniglich PreussiscJie gedogisclie Landesanstalt. See
Periodicals : Berlin.
Abhandlungen. Biinde 1-3, 5-10, Hefte 1-6. 8vo
& 4to. Berlin, 1872-94. Purchased.
. . . Neue Folge, Hefte 1-3, 5-8, 11-15. 8vo
& 4to. Berlin, 1889-94. Purchased.
Queensland. Geological Survey. (R. L. Jack; Government Geo-
logist.) Annual Progress Report of the Geological Survey for the
year 1891. 4to. Brisbane, 1892.
( .) for the year 1892. 4to. Brisbane,
( .) Report on the Kangaroo Hills Silver and
Tin Mines, by R. L. Jack. 4to. Brisbane, 1892.
( .) Geological Observations in the Cooktown
District, by W. H. Rands. 4to. Brisbane, 1893.
( .). Report on the Grass-Tree Gold Field, near
Mackay, by R. L. Jack. 4to. Brisbane, 1893.
Queustedt, F. A. Die Mastodonsaurier im GrUnen Keupersandsteino
'Wurttemberg'ssind Batrachier. FoL Tubingen, 1850. Purchased*
Quiroga, F. El profesor D. Juan Vilanova y Piera. 8vo. Madrid,
1893.
Sobre la existencia de la humita en algunas calizas arcaicas
de la Sierra de Guadarrama. 8vo. Madrid, 1893.
— . See Calderon, S.
Rands, W. H. See Queensland and Maps : Queensland.
Ruxde, T. Mellard. High-level Shelly-sands and Gravels. 8vo.
London, 1893.
The Drift Beds of the Moel Tryfaen Area of the North
Wales Coast. 8vo. Liverpool, 1893.
— . TThc Genesis of Mountain Ranges. 8vo. London, 1893.
262
ADDITIONS TO THE LIBKART.
[Nov. 1894,
Reade, T. Mellaril. Continental Growth and Geological Periods.
8vo. London, 1894.
. On the Results of Unsymmetrical Cooling and Redistribu-
tion of Temperature in a Shrinking Globe, as applied to the
Origin of Mountain Ranges. 8vo. London, 1894.
Reid, Clement. A fossiliferous Pleistocene Deposit at Stone, on the
Hampshire Coast. 8vo. London, 1893.
. Desert or Steppe Conditions in Britain : A Study of Newer
Tertiary Geology. 8vo. London, 1893.
. On Paradoxocarpus carinatus, Nehring, an extinct fossil
plant from the Cromer Forest-bed. 8vo. Norwich, 1893.
. See Woodward, U. B.
Reiss, W., und A. Stiibel. Reisen in Sud-Amerika. Das Hochge-
birge der Republik Ecuador. I. Petrographische Untersuchungen.
1. West-Cordillere. Lieferung 2. Atacatzo bis Iliniza, von
Ernst Elich, III. ; Rio Hatuncama bis Cordillera de Llangagua,
von A. Klautzsch, IV. 4to. Berlin, 1893. Purchased.
, . Reisen in Sud-Amerika. Geologische Studien in der
Republik Colombia. III. Astronomische Ortsbestimmungen, bear-
beitet von Bruno Peter. 4to. Berlin, 1893. Purchased.
Renault, B. See Bertrand, C. E., and France.
Renevier, E. Geologie des Prealpes de la Savoie. 8vo. Lausanne,
1893.
Reports, Parliamentary. See Great Britain.
Ricciardi, Leonardo. La recente eruzione dello Stromboli in re-
lazione alia frattura Capo Passero-Vulture e sulla influenza luni-
solare. 8vo. Reggio Calabria, ? 1893.
Richards, Sir G. H. Report on the present state of the Navigation
of the River Mersey (1893) to the Right Honourable the Com-
missioners for the Conservancy of the Mersey. 8vo. London,
1894.
Richthofen, F. Fr. von, Festschrift. See Blanckenhorn, Max ; Dry-
galski, E. von ; Fischer, Hans ; Freeh, F. ; Hahn, E. ; Hettner,
A. ; Kretschner, K. ; Oldham, H. Y. ; Philippson, A. ; Pohlmann,
R ; Rohrbach, C. E. M. ; Schott, G. ; Sieger, R. ; Steffen, H. ;
and Wegener, G.
Ricletts, C. On some conditions existing during the formation of
the older Carboniferous Rocks. 8vo. Liverpool, 1893.
Ridgway, R. See Periodicals : Washington. Smithsonian Insti-
tution.
Riley, C. V. See Periodicals : Washington. Smithsonian Insti-
tution.
Vol. 50.] ADDITIONS TO THE LIBRARY. 263
Hitter, E. Les Massifs de Beaufort et du Grand-Mont. 8vo.
Geneva, 1894.
. See Duparc, L.
Rogers, S. The Diamond Prospecting Core Drill. 8vo. Truro,
1892.
Kohrbach, C. E. M. Zur mathematischen Behandlung geograph-
ischer Problcme. (F. Fr. von Kichthofen, Festschrift, 345.) bvo.
Berlin, 1893. Purchased.
Ross, C. R. See Woodward, H. B.
Roth, Justus. AUgemeine und chemische Geologic. Band iii -
Abtheilung 1 & 2. 8vo. Berlin, 1890 & 1892. Purchased.
i
Rothpletz, A. Ein geologiscbcr Querschnitt durch die Ost-Alpen,
nebst Anhang iiber die sogenannte Glarner Doppelfalte. 8vo.
Stuttgart, 1894. Purchased.
Roziere, De. Description do l'-figypte, recueil des observations et
des rechcrches qui ont etc faitcs en £gypte pendant l'expedition
de l'Arme'e Fran^aise. Seconde Edition. Tome xxi. Histoire
Katurelle. Mineralogie. 8vo. Paris, 1826. (With Atlas of
15 plates.) Purchased.
Russell, J. C. See Uuited States.
Russia. Comiti Geologique. Carte Geologique de la Russie d'Europe,
e'chellel : 520,000, par A.Karpinsky,S. Nikitin,Th.Tschernyschev,
N. Sokolov, A. Mikhalsky, etc. Note Explicative. 8vo. St.
Petersburg, 1893.
. . See Maps : Russia.
Rylands, T. O. The Geography of Ptolemy elucidated. 4to.
Dublin, 1893.
St. John, O. See Elinois.
Samuels, L. A. Origin of the Bendigo (Victoria) Saddle Reefs and
the Cause of their Golden Wealth. 8vo. Bendigo, 1893.
Sandbcrger, F. von. Das Erzvorkommen von Cinque valle bei
Roncegno im Val Sugana ca. 30 km. dstlich von Xrient. 8vo.
Munich, 1893.
. Ueber einigc Conchylien aus pleistociinen Kalktuffen Schwe-
dens. 8vo. Stuttgart, 1893.
. Zur Geologie der Gegond von Homburg vor der Hohe. 8vo.
Wiesbaden, 1893.
Saporta, G. do. See France. Paleontologie Franchise.
Sauer, A. See Baden.
vol. l w
Digitized by Google
264 ADDITIONS TO THB LIBRARY. [Nov. 1 894,
Sauvage, IL E. Bassin Houiller et Permien d'Autun et d'£pinac
Fasc. v. Poissons Fossiles. 4to. Paris, 1893.
— . Description de deux espoces nouvelles de Poissons du Ter-
rain Kimmeridgien du Cap de la Here. 8vo. Havre, 1893.
■ -. Note sur quelques Poissons du Calcaire Bitumineox d'Or-
bagnoux (Ain). 8vo. Autun, 1893 ?
Sawyer > A. R. The Goldfields of Mashonaland. 8vo. Manchester,
1894.
. See Cape of Good Hope and Maps.
Saxony. Die geologi&che Lande&u ntersu ch u ng des Konigrtich* Sarh-
sen. Erlauterungen zur geologische Specialkarte des Konigreichs
Sachsen. Blatter 21, 22, 23 & 38, 30, 37, 9S & 24, 47, 49, 50.
53, 66, 07, 08, 70, 82, SJi Svo. Leipzig, 1891-93.
. . Profile durch das Steinkohlcnbecken des Plan-
en'schen Grundes (das Dohlener Becken) bei Dresden, von
R. Hausse. 8vo. Leipzig, 1892.
. See Maps.
Sc?iencl"t A. Gebirgsbau und Bodengestaltung von D cuts ch-sud west -
Afrika. 8vo. 1893.
Schirmcr, IL Le Sahara. 8vo. Paris, 1893. Purchased.
Schmidt, C. See Switzerland.
Schott, G. Ueber die Dimensionen der Meereswellen. (F. Fr. von
llichthofen, Festschrift, 235.) 8vo. Berlin, 1893. Purchased.
Schuchert, C. 8ee Diller^ J. S.
Schulz, A. Grundziige einer Entwickelungsgeschichte der Pflanzen-
welt Mitteleuropas seit dem Ausgang der Tertiorzeit. 8vo. Jena,
1894. Purchased,
Schiitze, A. Geognostisohe-bergmannische Beschreibung der beiden
W alden burger Berg- Iteviere. (Den Theilnehmern am V. allgemei-
nen Deutschen Bergmannstage gewidmet, 1892.) 4to. Walden-
burg, 1892. Presented by IL Bauerman, Esq., F.O.S.
Scudder, S. IL Contributions to Canadian Palaeontology. Vol. ii.
Canadian Fossil Insects. 2* The Coleoptera hitherto found fossil
in Canada. 8vo. Ottawa, 1892?
. Tertiary Tip\did&% with special reference to those of Floris-
sant, Colorado. 8vo. Philsdelphia, 1894.
The American Tertiary Aphidee. 4to. Washington, 1894.
— — . See United States.
Seddon, B. J, See New Zealand.
V
Vol. 50.]
ADDITIONS TO THE LIBRARY.
265
Sederholm, J. J. See Finland.
Serbin, A. Bemerkungen Strabos iiber den Yulkanismus und
Beschreibung der den Griecben bekannten vulkanischen Gebiete.
8vo. Berlin, 1893. Purchased.
Seunes, J. See France.
Seward, A. C. See British Museum.
Sherborn, C. Davie*. An Index to the Genera and Species of the
Foraminifera. Part I. A to NON. (Smithsonian Institution.)
8vo. Washington, 1893. {Library copy.)
, and B. B. Woodward. On the Dates of the 4 Encyclopedic
Methodique ' (Zoology). 8vo. London, 1893.
Shone, W. Subterranean Erosion, and some of its effects 8vo
Chester, 1893.
. The Cause of Crateriform Sand Dunes and Cwms. 8vo
Chester, 1893.
. Note of tho Submerged Forest at Rhyl. 8vo Chester
1893.
Sieger, R. Zur Entstehungsgeschichto des Bodensees. (F. Fr. von
Richthofen, Festschrift, 55.) 8vo. Berlin, 1893. Purchased.
Skertchly, S. B. J. See Great Britain.
Smith, E. A. Undorthrust Folds and Faults. 8vo. New Haven
Conn., 1893.
. See Alabama.
Smith, William. Observations on the utility, form, and manage-
ment of Water Meadows, and the draining and irrigating of Teat
Bogs, with an account of Prisley Bog. 8vo. Norwich, 1806.
Presented by Frank Jiutley, Esq., F.G.S.
Smith, Worthington G. Man : the Primeval Savage. His Haunts
and Relics from the Hill-tops of Bedfordshire to Blackwall. 8vo
London, 1894. Purchased.
Sokolov, N. See Russia and Maps : Russia.
South Australia. Geological Survey. (£/. Y. L. Brown, Government
Geologist.) On Additional Silurian and Mesozoic Fossils from
Central Australia, by R. Etheridge, Jun. A Supplement to
Parliamentary Papers, No. 158, 1891 ; No. 23, 1892. 4to
Adelaide, 1893.
. See Brown, If. Y. L,
Spain. Comision del Mapa Oeoldfjico. Boletin. Tomo xix. (A no
1892.) 8vo. Madrid, 1893.
P. Palacios. Resena geologica de la region meridional de la provincia
de Zaragoza, 1. — J. Alniera y A. BofilL Aloluscos foailes de los terreuos
266 ADDITIONS TO THE LIBRABT. [NOV. 1894,
terciariog superiores de Cat&luna, 115. — C. Barrois. Ohservacionea pobre
el terreno siluriano de log alrededores de Barcelona, 245.— W. Kilian.
Estudios paleontologicos acerca de loe terrenos secundaria y terciario^ de
Andalucia, 663.
Spain. Common del Mapa Geoldgico de Expafia. Hemoriaa. De-
scripcion Fisica y Geologic* de la Provincia de Vizcaya por Bamon
Adan de Yarza. 8vo. Madrid, 1892.
Spencer, J. W. The Iroquois shore north of the Adirondack*.
8vo. Kochestert N.Y., 1891.
. Terrestrial Submergence south-east of the American Con-
tinent. 8vo. Rochester, N.Y., 1893.
. Deformation of the Lundy Beach and Birth of Lake Erie.
8vo. New Haven, Conn., 1894.
. See Georgia.
Springer, F. See Illinois.
Stanton, T. W. See Diller, J. S.
Steffen, H. Beit rage zur Topographic und Geologic der andinen
Region von Llanquihue. Mit einem petrographiscben Anhang
von R. Pbhlraann : Bemerkungen iiber Gesteine aus Llanquihue.
(F. Fr. von Richthofen, Festschrift, 407.) 8vo. Berlin, 1893.
Purchased.
Steinmann, G. See Baden.
Stejneger, L. See Periodicals : Washington. Smithsonian Insti-
tution.
Sterzel, J. T. Die Flora dos Rothliegenden im Plauenschen Grunde
bei Dresden. 8vo. Leipzig, 1893. Purchased.
Stevenson, J.J. On the Use of the Name " CatskiU." 8vo. New
Haven, 1893.
. Origin of the Pennsylvania Anthracite. 8vo. Rochester,
N.Y., 1893.
Stirling, James. See Victoria.
Stokes, Arthur H. See Great Britain.
Stonier, G. A. See New South Wales.
Stubel, A. See ReiBS, W.
Suess, E. Ueber neuere Ziele der Geologie. 8vo. Gdrlitzv 1893.
Purchased.
Svedmark, E. See Sweden.
Svenonius, F. Set Sweden.
Digitized by Google
Vol. SO.] ADDITIONS TO THE LI BRAKY. 267
Sweden. Sverigft GeologUht Undersohning.
Ser. A a. Beskrifning till Kartblad. Skalen 1 : 50,000. No. 108,
Glimakra and No. 109, Simrishamn. 8vo. Stockholm, 1892.
Scr. A b. Beskrifning till Kartblad. Skalen 1 : 200,000. No. 13,
Yarberg; No. 14, Nvdala ; and No. 15, Lenhofda. 8vo.
Stockholm, 1892 and 1893.
Scr. B b. No. 7. Beskrifning till agronomiskt geologisk Karta
bfver Torresby. Skala 1 : 15,000. 1892.
Ser. C. Afhandlingar.
No. 112. Sveriges kambrisk-siluriska Hyolithidao och Conu-
lariidie, af G. Holm. 4to. Stockholm, 1893.
No. 116. Om Kvartsit-sparagmitonra'det i Sveriges sydliga
fjelltrakter, af A. G. Hogbom. 8vo. Stockholm, 1891.
No. 117. Bidrag till Kiinnedomen om de glaciale fbreteelserna i
Norrbotten, af K. A. Fredholm. 8vo. Stockholm, 1892.
No. 118. Skotska byggnadssatt for naturlig sten, af H. Lund-
bohm. 8vo. Stockholm, 1891.
No. 119. Agronomiskt-botaniska studier i norra Dalarne, af
A. G. Kellgren. 8vo. Stockholm, 1892.
No. 120. Untersuchungen iiber fossile Holzer Schwedens, af
H. Conwentz. 4to. Stockholm, 1892.
No. 121. Om mynningen hos Lituites, af G. Holm. 8vo.
Stockholm, 1892.
No. 122. Meddelandcn om jordstbtar i STerige, II., af E.Sved-
mark. 8vo. Stockholm, 1892.
No. 123. Anteckningar Mn en i praktiskt syfte fbretagen
geologisk resa i Vesterbottens lan, af A. Blomberg. 8vo.
Stockholm, 1892.
No. 124. Studier bfver de glaciala aflagringarna i Upland, af
A. G. Hogbom. 8vo. Stockholm, 1892.
No. 125. Om skiffern med Clonograptus tinellui, &c., &c, af
J. C. Moberg. 8vo. Stockholm, 1892.
No. 126. Om berggrunden i Norrbottens lan och utsigterna
till brytvarda altitfbrekomster dcrstades, af P. Svenonius.
8vo. Stockholm, 1892.
No. 127. Apatitfbrekomster i Norrbottens malmberg, af H.
Lundbohra. 8vo. Stockholm, 1892.
No. 128. Om marken efter isdamda sjbar i Jemtlands fjelltrakter,
&c, af A. G. Hogbom. 8vo. Stockholm, 1893.
No. 129. Om stenindu8trien i Fdronta staterna, af H. Lundbohm.
8vo. Stockholm, 1893.
No. 130. Bidrag till Kiinnedomen om logerfoljden inom den
kambriska sandstenon, af N. O. Hoist. 8vo. Stockholm,
1893.
No. 131. Praktiskt geologiska undcrsbkningar inom Hallands
lan, af G. De Geer, J. Jbnsson, P. Dusen, T. Palmberg, och
E. Svedmark. 4to. Stockholm, 1893.
No. 132. Om berggrunden i Vesternorrlands kusttrakter, af
H. Lundbohm ; Om postarkaiska eruptiver inom det svensk-
finska urberget, &c, af A. G. Hogbom. 8vo. Stockholm, 1893.
263
ADDITIONS TO THE LIBRART.
[Nov. 1894,
No. 133. Om de porfyriska gSngbergarterna i ostra Smaland,
af 0. Nordcnskjold. 8vo. Stockholm, 1893.
No. 134. Ora hasselns forntida och nutida utbredning i Sverige,
af H. Hodstrdm. 8vo. Stockholm, 1893.
Sweden. Set Maps.
Switzerland. Commission der geologischen Katie der Schweiz. Beitrage.
7* Lieferung. Deuxieme supplement a la Description geologique
du Jura Neuchatelois, Vaudois, des Districts adjacents du Jura
Fram-ais et do la Plaine Suisse, par August© Jaccard. 4to.
Berne, 1893.
. . . 21' Lieferung. Geologische Beschreibung
des Westlichen Theils der Aarmassive. enthalton auf dem nordlich
der Rhone gelegenen Theilo des Blattes xviii. der Dufour-Karte,
von Edmund von Fellenberg und Casimir Moesch ; mit petro-
graphischen Beitragen von Carl Schmidt. 4to. Bern, 1893.
With obi. 4to. Atlas.
. . . 32* Lieferung. Die Kontaktzone von Kreide
und Tertiiir am Nordrande der Schweizeralpen vom Bodensee bis
zum Thunersee, von Carl Burckhardt. 4to. Bern, 1893.
. See Maps.
4 Talisman.' See 4 Travailleur.'
Tarr, R. S. Economic Geology of the United States. 8vo. Xe*
York, 1894. Purchased.
Tate, Ralph. Correlation of the Marine Tertiaries of Australia.
8vo. Adelaide, 1893.
. Critical Remarks on A. Bittners 1 Eohiniden des Tertiars
von Australien.' 8vo. Adelaide, 1893.
. Inaugural Address, read at the Adelaide Meeting of the
Association for the Advancement of Science, September 26th, 1893.
8vo. Adelaide, 1893.
. The Cambrian Fossils of South Australia, 8vo. Adelaide,
1893.
. The Gastropods of the Older Tertiary of Australia. Part W.
8vo. Adelaide, 1893.
. Unrecorded Genera of the Older Tertiary Fauna of Australia,
including Diagnoses of some New Genera and Species. 8vo.
Adelaide, 1893.
Tale, Thomas. The Sources of the River Aire, and Note on an
Intermittent Spring at Malham. 8vo. Halifax, 1879.
. Yorkshire Petrology. Parts 1 & 2. 8vo. Halifax, 1887
and 1889.
. On the so-called Ingleton Granite. 8vo. Halifax, 1890.
Vol. 50.]
ADDITIONS TO THE LIBRARY.
269
Tate, Thomas. Lake Country Rocks. 8vo. Le3ds, 1892.
. Notes on Recent Borings for Salt and Coal in the Tees
District. 8vo. London, 1892.
. The Yorkshire Boulder Committee and its Fifth Year's Work.
8vo. Leeds, 1892.
The Glacial Deposits of the Bradford Basin. 8vo. Leeds,
1875.
Texas. Geological Survey. (E. T. Dumble, State Geologist.)
A Preliminary Report on the Vertebrate Palaeontology of the
Llano Estacado, by E. D. Cope. 8vo. Austin, 1893.
Thompson, W. See Maps: Queensland.
Thomson, J. P. The Geographical "Work of. 8vo. Brisbane, 1893.
Presented by tits Royal Geographical Society of Australasia.
Thiirach, H. See Bavaria.
Tolstopiatow, M. Recherches Mine'ralogiques. Edition posthume.
8vo. Moscow, 1893. Purchased.
Touche, T. D. la. See India.
Trabucco, O. Sulla vera posizione dei Terreni Terziari del Bacino
Piemontese. Parte 1\ 8vo. Pisa, 1893.
* Travailleur 1 et ' Talisman/ Expeditions Scientifiques du * Tra-
vailleur ' et du * Talisman' pendant les annees 1880, 1881,
1882, 1883. Ouvrage public sous les auspices du Ministre de
l'lnstruction publiquo sous la direction de A. Milne-Edwards.
Echinodermes, par E. Perrier. 4to. Paris, 1894. Purchased.
Tschermak, G. Lehrbuch der Mineralogie. 4a Auflage. 8vo.
Vienna, 1894. Purchased.
Tschernyschev, Th. Sec Russia and Maps : Russia.
Ulrich, E. 0. See Illinois.
Ulrichy 0. H. F. On a Meteoric Stone found at Makariwa near
Invercargiil, New Zealand. 8vo. London, 1893.
United Kingdom. See Groat Britain.
United States. Department of Agriculture. "Weather Bureau. First
Biennial Report of the Maryland State Weather Service for the
years 1892 and 1893. ( W. B. Clark, Director.) The Climatology
and Physical Features of Maryland. 8vo. Baltimore, 1893.
. Department of the Interior. United States Geological Survey.
Eleventh Annual Report, 1889-90. Parts 1 & 2. bvo. Wash-
ington, 1891.
Bulletin. No. 82. Correlation Papers:
Cretaceous, by C. A. White. 8vo. Washington, 1891.
2 70 ADDITIONS TO TffB LIBRAKT. [Nov. 1 894,
United States. Department of the Interior. UmUed Statee Geological
Survey. Bulletin. No. 83. Correlation Papers: Eocene, by
W. B. Clark. 8vo. Washington, 1891.
i . . . . No. 84. Correlation Papers: Neo-
cene, by W. H. Dall and G. D. Harris. 8vo. Washington, 139&
No. 85. Correlation Papers: The
Newark System, by J. C. Russell. 8vo. Washington, 1892.
No. 86. Correlation Papers: Archaean
and Algonkian, by R. C. Van Hise. 8vo. Washington, 1892.
— . . . . No. 90. Report of Work done in
the Division of Chemistry and Physics, mainlv during the Fiscal
Year 1890-91, by F. W. Clarke. £vo. Washington, 1892.
— . . . . No. 91. Record of North- American
Geology for 1890, by N. H. Darton. 8vo. Washington, 1&91.
No. 92. The Compressibility of
Liquids, by C. Barus. 8vo. Washington, 1892.
— . » . . No. 93. Some Insects of special
interest from Florissant, Colorado, and other points in the Tertiaries
of Colorado and Utah, by S. H. Scudder. 8vo. Washington, 1892.
— . . . . No. 94. The Mechanism of Solid
Viscosity, by C. Barus. 8vo. Washington, 1892.
— . . . . No. 95. Earthquakes in California
in 1890 and 1891, by E. S. Holden. 8vo. Washington, 180ft
— . . . . No. 96. The Volume Thermo-
dynamics of Liquids, by C. Barus. 8vo. Washington, 1892.
— . . . Mineral Resources of the United States,
Calendar year 1891, by D. T. Day. 8vo. Washington, 1893.
Monographs. Vol. xvii The Flora of the
Dakota Group, by the late Leo Lesquereux, edited by F. H.
K now 1 ton. 4to. Washington, 1891.
Vol. xviii. Gasteropoda and Cephalo-
poda of the Raritan Clays and Greensand Marls of New Jersey,
by R. P. Whitfield. 8vo. Washington, 1892.
Vol. xx. Geology of the Eureka
District, Nevada, by Arnold Hague. 4to. Washington, 1892.
Atlas to accompany the Monograph on the
Eureka District, Nevada, by Arnold Hague. FoL Washington,
1883.
Van Hise, C. R. See United States.
Vara, M. G. See Blondeau.
Digitized by Google
Vol. 50.]
ADDITIONS TO TITE LIBRARY.
271
Victoria. Department of Mines. Annual Report of the Secretary
for Mines for the year 1892. 4to. Melbourne, 1S93.
. . Special Reports. Reports on the Victorian Coal-
fields (No. 2), by James Stirling. 4to. Melbourne, 1893.
Vilanova y Piera, J. See Quiroga, F.
Voltz, II. Die Bergwerks- nnd Huttenverwaltungen des Ofccr-
echlesischen Industrie- Bezirks. (Den Theilnehraern am V. All-
gemeineo Deutschen Bergmannstage in Breslau gcwidmct, 1892.)
8vo. Kottowitz, 1892. Presented by H. Bauerman, Esq., F.G.S.
"Wachsmuth, C. See Illinois.
Wadsworth, M. E. A paper on the Michigan Mining School. 8vo.
Lansing, 1891.
"Wallace, A. R. Island Life : or, the Phenomena and Causes of
Insular Fauna9 and Floras, including a revision and attempted
solution of Geological Climates. 8vo. London, 1880. Pur-
chased.
Wrallis, A. if. The Portland Stone Quarries. 8vo. Dorchester,
1891.
"NValther, J. Einleitung in die Geologie als historische Wissen-
schaft. Zweiter Theil. Die Lebensweise der Meeresthicre.
8vo. Jena, 1893. Purchased.
T>Yardh, Tlwmas. On Sewage Treatment and Disposal : for Cities,
Towns, Villsges, Private Dwellings, and Public Institutions.
8vo. London, 1893.
WaicrJiouse, F. If. Index Generum Avium. A list of the Genera
and Subgenera of Birds. 8vo. London, 1889.
"Wegener, G. Die Entschleierung dor unbekanntcsten Theile von
Tibet und die tibetische Centralkctte. (F. Fr. von Richthofen,
Festschrift, 385.) 8vo. Berlin, 1893. Purchased.
"Werner, A. G. Neue Theorie von der Entstehung der Giinge, mit
Anwendung auf den Bergbau, besondcrsden freibergischen. 8vo.
Freiberg, 1791. Purchased.
"Western Australia. See Hart, F., and Fraser, M. A. C.
"Whitakcr, "W. See Great Britain.
"White, C. A. See United States.
Whitfield, R. P. See United States.
Wickes, W. H. See Woodward, H. B.
Wilkinson, C. S. See New South Wales.
Willcocks, W. See Egypt.
VOL. L.
272 ADDITIONS TO THE LIBRARY. [Nov. 1 894,
Williams, O. IT. A new Machine for Cutting and Grinding Thin
Sections of Rocks and Minerals. 8vo. New Haven, Conn., 1S93.
. On the use of the terms Poikilitic and Micropoikilitic in
Petrography. 8vo. Chicago, 1893.
. Piedmontite and Scheelite from the Ancient Rhyolite of
South Mountain, Pennsylvania. 8vo. New Haven, Conn., 1693.
. The Distribution of the Ancient Volcanic Rocks along the
Eastern Border of North America. 8vo. Chicago, 1 894.
, and W. B. Clark. Outline of the Geology and Physical
Features of Maryland. 4to. Baltimore, 1S93.
Williams, J. F. See Arkansas.
Wfl*on, E. Guide to the Bristol Museum. 3rd edition. 8vo.
Bristol, 1893.
Wilson, E. See Woodward, H. B.
Wiltshire, Thomas. See Jones, T. Rupert.
Winchell, N. U. See Minnesota.
Win wood, H. H. See Woodward, H. B.
Woods, Henry. Elementary Palaeontology for Geological Students.
8vo. Cambridge, 1893.
. Woodwardian Museum, Cambridge. Catalogue of the
Fossils in the Students' Stratigraphical Series. 8vo. Cambridge,
1893.
Woodward, A. Smith. Further Notes on Fossil Fishes from the
Karoo Formation of South Africa. 8vo. London, 1893. Pre-
sented by David Draper, Esq., F.O.S.
. See New South Wales.
Woodward, B. B. See Sherborn, C. Davies.
Woodward, Henry. See Jones, T. Rupert.
Woodward, H. B. A Memoir of Caleb R. Rose, F.R.C.S., F.G.8.
8vo. Norwich, 1893.
. On a Bed of Oolitic Iron-ore in the Lias of Raasay. 8vo.
London, 1893.
— . President's Address read to the Members of the Norfolk
and Norwich Naturalists' Society, March 28th, 1893. 8yo.
Norwich, 1893.
■ . Geology in the Field and in the Study. 8vo. London, 1894.
Vol. 50.]
ADDITIONS TO THE L1BRART.
273
Woodward, H. B. See Great Britain.
, Clement Reid, and J. H. Blake. Excursion to Norwich, the
Bure Valley, Cromer, and Lowestoft. 8vo. London, 1893.
, H. H. Winwood, W. H. Wickes, and E. Wilson. Excursion
to Bath, Midford, and Dundry Hill, in Somerset, and to Bradford-
on-Avon and Westbury, in Wiltshire. 8vo. London, 1S93.
Woodward, Harry Page. See Maps : Western Australia.
AVoodwardian Museum, Cambridge. See Woods, Henri/.
Worthen, A. H. See Illinois.
Wray, L., Jun. Alluvial Tin Prospecting (Perak Museum Notes,
No. 2). 8vo. Taiping, 1893.
Wright, G. F. Man and the Glacial Period ; with an Appendix on
Tertiary Man, by H. W. Haynes. 8vo. London, 1892. Pur-
chased.
"Wyatt, F. The Phosphates of America. Fifth Revised Edition.
8vo. New York, 1894. Purchased.
Zirkel, F. Lehrbuch der Petrographie. 2* Auflage. Band ii
8vo. Leipzig, 1894.
Zittel, K. A. Handbuch der Pakeontologie. Abth. 1. Palaeo-
zoologie. Band iv. Lief. 1-3. 1892. Purchased.
3. Maps, &c.
Names of Donors in Italics.
Attica. Geologische Karte von Attika, begonnen von It. Lepsius
und H. Bucking, fortgefiihrt und herausgegeben von R. Lepsius.
Fol. Berlin, 1891. Purcliased.
. See Books : Lepsius, R.
Aubert, F. Carte Geologiquo provisoire de la Tunisie. Scale
dm- Purchased, 1892.
. See Books.
Bucking, H. See Attica.
Cabanas, L. See Mexico.
Castillo, Antonio del. See Mexico.
Cooke, G. H. See New Jersey.
274 ADDITIONS TO THE LIBRARY. [XoV. 1S94,
Dunn, E. J. Geological Sketch Map of the Stormberg Coal Fields.
Scale 1 mile to an inch. 1893 ?
England and Wales. See Great Britain.
Finland. Finland* Geologuka Undersokning. Kartbladet Nos. 22
and 23 and 24. Scale ^J^-
Prance. Dep6t de la Marine. 1 Charts and Plans of various
Coasts and Ports.
. Ministvre des Travanx Publics. Carte Geologique detaillee
-*
de la France. Nos. 40. & 56, 45, OH, 62, 85, 127, 141, 147,
158, 223. Scale Purchated.
Germany. See Lepsius, R.
Great Britain and Ireland. Geological Survey. England and
Wales. 1-inch Maps. (Solid.) Sheets (X.S.) 330-334. Quarter-
sheets 4fi N.E ; 51 N.E. ; SI N.W. ; 101 S.W.„ N.E. ; 1M
X.W. ; IQ1 N.E. ; 110. S.E. N.S. Isle of Wight flO].
. . . 1-inch Maps. (Drift.) Sheets CN.S.) 330-
334. Quarter-sheets 46 N.E. ; 4S, S.E. ; SO N.E. : >i» X.W., S. W. ;
OS S.E.; lill N.E. ; 1115 S.W. N.S. Isle of Wight flO;.
. . . Index of Colours and Signs. 1874.
. . Ireland. Index of Colours and Signs. 1S74.
. . Scotland. 1-inch Maps. Sheet ILL
Presented by the Director-General.
. Ordnance Survey.
One-inch General Maps. England and Wales. New Series.
;> Quarter-sheets.
. Scotland. 5 Sheets.
. Ireland. 3 Sheets.
. Indexes, L
Greece. See Attica.
Harz. See Lossen, K. A.
Ireland. See Great Britain.
Jack-, R. L. See Queensland.
Karpinsky, A. See Russia.
Uoogle
Vol. 50.] ADDITIONS TO THE LIBRARY. 275
Lepsius, R. Geologische Karte des Deutschen Reichs. Lieferung i.
Blatt 22, Strassburg ; Blatt 25, Miilhausen. Scale iaA^ Gotha,
1894. Purchased.
. . Lief. ii. Blatt 17, Koln; Blatt 23, Stuttgart. Scale
fioo^iio- Gotha, 1894. Purcliased.
— . See Attica.
Lossen, K. A. Geognostische Uebersichtskarte des Harzgebirges.
Scale louIu00. Berlin. Purchased.
Mexico. Comision Geologica Mexicans. (Antonio del Castillo,
F.C.GJS., Director.)
Bosquejo de una Carta Geologica de la Republics Mexicana, por
Antonio del Castillo. Scale [jmmy Mexico, 1893.
Carta de los Meteoritos de Mexico, 6 Regiones de la Republica
en que ban caido fierros y piedras meteoricas, por Antonio del
Castillo. Scale Mexico, 1893.
Carta Minera de la Republica Mexicana, por Antonio del Castillo.
Scale 5^00- Mexico, 1893.
Cortes Geologicos de Pozos Artesianos abiertos en la Gran Cuenca
de Mexico, por Antonio del Castillo. Mexico, 1893.
Piano Geol6gico de las Minas de Fierro de la Ferriera de la En-
carnacion y del Distretto Minero de S. Jose del Oro, por Antonio
del CastiUo, L. Cabanas y E. Ordonez. Scale jq-^. Mexioo,
1893.
Piano Geologico del Penon de los Baiios, por Antonio del Castillo.
Scale ±. Mexico, 1893.
Piano Geologico Minero del Real de San Antonio y el Triunfo, de
la Baja California, por Antonio del Castillo. Scale
Mexico, 1889.
Piano Geologico y Pctrografico de la Cuenca de Mexico, Region
S.W., por Antonio del Castillo. Scale 200000' Mexico, 1893.
New Jersey. Geological Survey. Atlas. Sheets Nos. 2, 3, 4, 6, 7,
and 16. Scale 1 mile to an inch. Presented by O. II. Cooke,
State Geologist.
New South Wales. Department of Mines and Agriculture. Geo-
logical Map of New South Wales. Scale about 16 miles to
1 inch. Prepared under the direction of E. F. Pittman, A.R.S.M.,
Government Geologist. Sydney, 1893.
Ordonez, E. Am Mexico.
vol. L. y
276 ADDITIONS TO THE LIBRARY. [Nov. iSoi.
Queensland. Geological Surrey. Geological Map of Charter*
Towers Goldfield, Queensland, by R. L. Jack, \V. IL Rands, and
A. G. Maitland. Topography by W. Thompson. Scale ± chains
to an inch. In six sheets. 1894.
Russia. Comite Geologique. Carte Geologique de la Russie d'Europe,
par A. Karpinsky (Directeur), S. Nikitin, Th. Tschernyschev,
N. Sokolov, A. Mikhalsky, etc. Scale -^ooo' ^ 8^ieets-)
Sawyer, A. R. Sketch Map showing the relative position of the
most important Mashonaland Goldfields as at present known.
Scale 1 inch=42 miles. 1894.
. Geological Sketch Map of part of the Manica or Umtali
Goldficld. Scale 1 inch = 0u0 yards. 1894.
-. Geological Sketch Map of the Victoria Goldfield [Mashona-
land]. Scale 1 inch =2 miles. 1894.
. See Books.
Saxony. Geologische Landesuntersuchung des Kbnigreichs Sach&m.
Geologische Specialkarte. Blatt 23 und 38, Welka-Lippitsch ;
39 und 24, Baruth-Neudorf ; 50j Moritzburg-Klotzsche ; 66,
Dresden ; 70, Schirgiswalde-Schluckenau ; 82, Kreiseha-Hanichcn,
Scale 2o!ooo-
Scotland. See Great Britain.
Spain. Comision del Mapa GeoUgico de Espana. Nos. 1, 3, 4, 5,
7, 9, 11, 13, 14, and 15, Scale
Sweden. Sveriges Geohgislca Undersbhning. Karta.
Ser. Aa. i skalan 1 : 50,000. Bladet 1118 «fc
Ser. A6. i skalan 1 : 200,000. Bladet 13, 14, 15.
Ser. Bo. No. 1± Agronomiskt geologisk karta ofver Torreby.
Scale ^ 1892.
Switzerland. Commission der geohgischen Karte der Schweiz.
Blatt xi. Scale j^—. 1893.
Tunis. See Albert, F.
Western Australia. Geological Sketch Map. Scale 8JKJ-O00-. Harry
Page Woodward^ Government Geologist. Perth, 1894. Presented
through the Agent General for Western Australia,
15 Photographs of Fellows of the Society. Presented by Messrs.
Maull and Fox.
Digitized by Google
3'
Digitized by Google
Live Music
Archive
Librivox
Free Audio
Metropolitan Museum
Cleveland
Museum of Art
Internet
Arcade
Console Living Room
Open Library
American
Libraries
TV News
Understanding
9/11