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THE Da Wesedttera

OF THE ge

GEOLOGICAL SOCIETY OF LONDON.

EDITED BY

THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY.

Quod si cui mortalium cordi et cure sit non tantum inventis hzrere, atque iis uti, sed ad ultenora
penetrare; atque non disputando adversarium, sed opere naturam vincere; denique non belle et probabiliter
opinari, sed certo et ostensive scire; tales, tanquam veri scientiarum filii, nobis (si videbitur) se adjungant.
—Novum Orgunum, Prefatio.

VOLUME THE PIFTY-SECOND.

on I aa

1896. fi aan mitigy

*% *

it Gil 1930 re)

~~ oe
“i Las
LONDON:

LONGMANS, GREEN, AND CO.

PARIS: FRIED. KLINCKSIECK, 11 RUE DE LILLE; F. SAVY, 77 BOULEVARD) ST. GERMAIN.
LEIPZIG: T. O. WEIGEL.

SOLD ALSO AT THE APARTMENTS OF THE SOCIETY.

MDCCCXCVI.

Ltst
OF THE

OF FICHIERS

OF THE

GEOLOGICAL SOCIETY OF LONDON.

Elected February 21st, 1896.

Weyvy—e—ew™®

BrestVent.
Henry Hicks, M.D., F.R.S.

Wice-PrestVents.
Prof. T. G. Bonney, D.Se., LL.D., F.R.S. | Lieut.-General C..A. M*Mahon.
R. Lydekker, Hsq., B.A., F.R.S.

Secretaries.
J. E. Marr, Esq., M.A., F.R.S. | J.J. H. Teall, Esq., M.A., F.R.S.

PForetqnu Secretary.
Sir John Evans, K.C.B.,.D.C.L., F.R.S., F.L.S.

Creasurer.
W. T. Blanford, LL.D., F.R.S8.

COUNECIL.
H. Bauerman, Esq. Rev. Edwin Hill, M.A.
W. T. Blanford, LL.D., F.R:S. T. V. Holmes, Esq.
Prof. T. G. Bonney, D.Sc., LL.D., F.R.S.| R. Lydekker, Esq., B.A., F.R.S.
Horace T. Brown, Hsq., F.R.S. Lieut.-General C. A. M.Mahon. .

Prof. W. Boyd Dawkins, M.A., F.R.S. J. E. Marr, Esq., M.A., F.R.S.
Sir John Evans, K.C.B., D.C.L., F.R.S., | Prof. H. A. Miers, M.A., F.R.S.

F.L.S. HK. T. Newton, Esq., F.R.S.
Sir Archibald Geikie, D.Sc., LL.D., F.R.S.| F. Rutley, Esq.
J. W. Gregory, D.Sc. A. Strahan, Esq., M.A.
F. W. Harmer, Esq. J.J. H. Teall, Hsq., M.A., F.R.S.
R. 8S. Herries, Esq., M.A. Henry Woodward, LL.D., F.R.S8.

Henry Hicks, M.D., F.R.S.

Assistant-Decretary, Clerk, Librartan, anv Curator.
L. L. Belinfante, B.Se.

Assistants in Office, Library, and Hiluseum.
W. Rupert Jones. | Clyde H. Black.

TABLE OF CONTENTS.

Page
ANDREWS, CHARLES W., Esq. On the Structure of the Plesiosauria
Resour ome tC NG ie tenn Stray erteuelea « cin aonese a + 4 af * 246

ARNOLD-BemrosF, H. H., Esq. Discovery of Mammalian Remains
in the old River-gravels of the Derwent, near Derby.—Part I.. 497

Aston, Miss E., and Prof. T. G. Bonney. On an Alpine Nickel-
beam, Serpentine, with Pulourites 2.50.3 0... ogee le a alin A52

Batyore, F. pz Montessts DE. Seismic Phenomena in the British
iraapyiter. WC lslahes / KKK, NO MOTE) 250) to apsis' sles dial die » eeteel 651

Bonney, Prof. T. G. The Serpentine, Gneissoid, and Hornblende
ecus of the Lizard District.) (Plate. .sioiec se ieee = A)

, and Miss E. Aston. On an Alpine Nickel-bearing Serpen-
ole eM EULE PEM UELUES Ait rales is Nat ea ty he kle vlog d ¢ Ute «fon ile las 452

BucxMay, S.8., Esq., and Epwarp Witson, Esq. Dundry Hill:
its Upper Portion, or the Beds marked as Interior Oolite (g 5)
im the. Maps of the Geological Survey ... 2.60. 2s0600ccneees 669

Cooxz, J. H., Esq. Contributions to the Stratigraphy and Paleeon-
tology of the Globigerina-limestones of the Maltese Islands.
(ANUS REELS Sie octet Sais a eb ah, aD ae nL SA ae wae eae any eae nie 461

CrosFIELD, Miss M. C., and Miss E. G. Skeat. On the Geology of
the Neighbourhood of Carmarthen. (Plates XXV. & XXVI.). 525

Davin, Prof. T. W. EnekwortH. Evidences of Glacial Action in
Australia in Permo-Carboniferous Time. (Plate XII.) ...... 289

Dretey, R. M., Esq. Discovery of Mammalian Remains in the
old River-gravels of the Derwent, near Derby.—Part IL....... 501

Exes, Miss G. L., and Miss E. M. R. Woop. On the Llandovery
and Associated Rocks of Conway (North Wales) ............ 273

1V TABLE OF CONTENTS.

Page
FEInpEN, Col. H. W. Notes on the Glacial Geology of Arctic
Europe and its Islands.—Part I. Kolguev Island. With an
Appendix by Prof. TG. BONNEY cic ost ca oes « ae oe 52

5 Part II. Arctic Norway, Russian Lapland,
Novaya Zemlya, and Spitsbergen. With an Appendix by
Prof. T, G. Bonnzy 72

GarvineRr, C. 1, Esq., and S. H. Reynotps, Esq. The Kildare
inilier.; “(Plate SX VU 2 i, oka denen ek oon ee 587

GEIKIEF, Sir ARcHIBALD. The Tertiarv B>salt-Plateaux of North-
western Murope: (Plates: XV -XUX) i)... ok en 2 os 33]

GREENLY, Epwarp, Esq. The Geology of the Eastern Corner of
PAM S ey Ea. oss caret Sauantnc leona Gre, oun es 8 Lwin (OES

, and J. Horne, Esq.. On Foliated Granites and their Rela-
tions to the Crystalline Schists in Eastern Sutherland ........ 633

GreEcory, Dr.J.W. The ‘Schistes lustrés’ of Mont Jovet (Savoy). 1

Harker, ALFRED, Esq. On certain Granophyres, modified by the
Incorporation of Gabbro-fragments, in Strath, Skye. (Plates
PTE SS NOU Site cae Ciel, ho neha eine ts fos 2 ots Cee 320

Harmer, F. W., Esq. On the Pliocene Deposits of Holland and
their Relation to the English and Belgian Crags, with a
Suggestion for the Establishment of a new Zone, ‘ Amstelien,’
and some Remarks on the Geographical Conditions of the
Pliocene Epoch in Northern Europe. (Plates XXXIV. &
OKA DE ihe Cae Valls ecb alee oe hee an alee 748

Hicks, Dr. Henry. On the Morte Slates and Associated Beds in
North Devon and West Somerset.—Part I. (Plates X.& XI.) 254

Hux, the Rev. Epwin. On Transported Boulder Clay .......... 302

Hii, Witzitam, Esq., and A. J. Juxres-BrownE, Esq. A De-
limitation of the Cenomanian:—being a Comparison of the
Corresponding Beds in South-western England and Western

ranice. (Plate V.) . s acccsaaievaneis seua tenes ae 99
Hinpez, Dr. G. J. Description of New Fossils from the Carboni-
ferous Limestone. I. On Pemmatites constipatus, sp. nov., a
Lithistid Sponge. II. On Paleacis humilis, sp. nov., a new
Perforate Coral, with Remarks on the Genus. III. On the
Jaw-apparatus of an Annelid, Eunicites Reidie, sp. nov.
(Plates: KGL i OR TIE) ss, eee RR. Ok 438

Horne, J., Esq., and EK. GREENLY, Esq. On Foliated Granites and
their Relations to the Crystalline Schists in Eastern Sutherland. 633

Huu, Prof. Epwarp. Observations on the Geology of the Nile
Valley, and on the Evidence of the Greater Volume of the River
dea HOMME CTO Gd « waists te Nene cite meore saat inne coe a coke 308

TABLE OF CONTENTS. Vv

Page
Ippines, Prof. J. P. Extrusive and Intrusive Igneous Rocks as
Products of Magmatic Diiterentiation. (Plate XXIX.) ...... 606

JuKxxs-Browne, A. J., Esq., and W. Hitt, Esq. A Delimitation
of the Cenomauian :—being a Comparison of the Correspouding
Beds in South-western England and Western France. (Plate V.) 99

Lake, Puiiip, Esq. The British Silurian Species of Acidaspis.
rretecemy esr NWN i ba cA ta atin oo eee ae. dS 5's! ah oral ealtoied 235

, and S. H. Reynoxps, Esq. The Lingula-Flags and Igneous
Rocks of the Neighbourhood of Dolgelly. (Plate XXIV.) .... d11

Lamp.iuen, G. W., Esq. On the Speeton Series in Yorkshire and _-
. - CLOUT NE he cach rn iene Mee eee ae amr ee i79

Marr, J. E., Esq. Additional Notes on the Tarns of Lakeland .. 12
MercatFE, A. T., Esq. The Gypsum Deposits of Nottinghamshire

seem Deu Dene: | CAUSETECL.)) oa chown ow sacle arse ne ane ho 0 ee 46]
Pavuiow, Prof. A. P. On the Classification of the Scrata between

the Kimeridgian and Aptian. (Plate XXVII.).............. 542

Prewuer, Dr. C.S.pu Ricus. Glacial Deposits, Preglacial Val-
leys, and Interglacial Lake-formations in Subaipine Switzerland. 556

REED, F. R. Cowrer, Esq. The Fauna of the Keisley Limestone.
Seeetimiem (de lates Nek, WAX TE Aris ie aun aup'ens eon ge ys 407

Rem, CLemMEnt, Esq. The Eocene Deposits of Dorset .......... 490

ReyNoxps, 8. H., Esq.,and Puiyip Laks, Esq. The Lingula-Flags
‘and Iyneous Rocks of the Neighbourhood of Dolgelly. (Plate

“EET SCE 2 SO Neal ae 511
, and C. I. Garprner, Esq. The Kildare Inlier. (Plate ~
TEES RCTUL) 2 fae Ce tere NII OER Deh IE 587

Rur ey, Franx, Esq. On the Alteration of Certain Basic Eruptive
iocks irom Brent Tor, Deyon, (Abstract) .........6c0 505% 66

SKEAT, Miss KE. G., and Miss M. C. CrosFietp. On the Geology
of the Neighbourhood of Carmarthen. (Plates XXV.& XXVL.) 523

STRAHAN, A., Esq. On a Phosphatic Chalk with Holaster planus
at Lewes. With an Appendix on the Foraminifera and Ostra-
eMeb ye Cr AP NIAING HISQ. isl asset's ayeie 9 sels «mievavstash ® fue 463

——., On Submerged Land-surfaces at Barry, Glamorganshire.
With Notes on the Fauna and Flora. By CLEMENT REID, Esq.
And an Appendix on the Microzoa. By Prof. T. R. Jonzs
pate eR EOMENVAIN s HISQ Ct. arr oda as ciete a's sie ej cress os wee doe e's A474

TatmaGe, Prof. J. E. Notes concerning certain Linear Marks in
perumientany Timi: CAUSE AC.) ie cade cieidss sclecseee vewees 461

Wutson, Epwarp, Esq., and S. S. Buckman, Esq. Dundry Hill:
its Upper Portion, or the Beds marked as Inferior Oolite (g 5)
in the Maps of the Geological Survey ........0-eseseeeees 669

V1 TABLE OF CONTENTS.

Page
Woop, Miss E. M. R., and Miss G. L. Erurs. On the Llandovery
and Associated Rocks of Conway (North Wales) ............ 273
Woops, Henry, Esq. The Mollusca of the Chalk Rock.—Part I.
Gelanes AV.) Wehia t rete cpiaciie as Ge ss c+ oe ss eee 68

Woopwarp, Dr. Henry. On some Podophthalmatous Crustacea
from the Cretaceous Formation of Vancouver and Queen Char-

Hobie lands thease week sek sa ak s+ 6 oss nn 221
——. Ona Fossil Octopus (Calais Newboldi, J. de C. Shy. MS.)

from the Cretaceous of the Lebanon. (Plate VI.) .......... 229

PROCEEDINGS.

Proceedings of the Meotings. sui shies siete was ence > is i, Cx1x
PRUMUPISBEPOFE 4. y. Sik owog curls e sits ss ebe vs os ee Vili
List of ingheve BO: LAUDER: t.5 chon eee pe eiees Goes Ones en X1V
List piworeion Members. sc. «as >) esos Sone Ope h +, ceehen eee XXKV
lnist or Moreien Correspondents, ....-.ieceras soaene se XXV1
ieisteon AV ollaston Medallists, .......+.00 000000» 01+ ene =p XXVil
Piston Murchison Medallists, «i. 000 eso «2 + >> oe XXIX
asimst Muyell Medallists)’ :c\5;sc:s% ae» eee 0s outs ses pees ee kk
ikiecoo: wissby Medallists ¢ oi... sauce evs aca cise er sles Roe 4.0.41
Applications of the Barlow-Jameson Fund ............0e+00e XXxl
CTL MEL: ieee sh. via p inks se 4s ais w oie e-waste oe XXXli
PAumeEU ROL Jee NUGO AIS, (GLE. {is i » iaje aid Bias (amg uts8)s (pcos b sleet, XXXIX
Anniversary Address ..... Rate i iw Pate GR eter oh xc isk Waa Se Alo eee hi
Bpecial General Meobine «2.04% e550.9 25.6 eee a oe cir 4 ok One CXX1V

Dawson, Sir Witittam. On Eozoon canadense ......0...05.. CXXVIl
Hicks, Dr. Hunry.. Announcement of decease of Sir Joseph
THES IaNCIN 5 Siete Outlet At SII Nu a CXXVi

Warts, W. W., Esq. On Specimens from the Olenellus-zone at
INTIMA VON A/es0s cea Sapa CAI ae eh. g Sy oe ae vi

LIST OF THE FOSSILS DESCRIBED AND FIGURED
IN THIS VOLUME.

[In this List, those Fossils the names of which are printed in Roman type
have been previously described. ]

Name of Species. | Formation. | Locality. | Page
PoRIFERA.
ete mee | Yoredale Beds . | Yorkshire ...... | 438
ANTHOZOA.
Paleacis cuneiformis. Pl. xxiii.) { St. Louis .
AEC MOND sacaescon sane sesesnane- { Group).2-522--- \ Tndiiamay <.>.2-22. 445
humilis, Pi. xxiii. figs. 1-| { Carboniferous
MRE is de jsieieole vaansewe enna { Limestone ... } Stonyhunst Pals cal
— obtusa. Pl. xxiii. figs. 17-| { Carboniferous
RUSTE eee suis cals asiaidaduisne seid { Limestone ... | Wexford qLane) Eee
TRILOBITA.
Acidaspis Barrandei. PI. viii. figs.| Wenlock Lime-
1-3 : Bee sctasty sclectci(u<caabrain wolsaivins.sni BLOM seate. \ Lonely ses ae
Bright. Pl. vii. fig. 5! ...... et ae Me } Do. & Malvern| 236
——convera, PI, xxi. fig. 6 ...... He a aa ' Keisley eooeree 425
coronata. PI. vii. fig. 6...... is me ee Various’: 2:22... 237
crenata. Pl. vii. figs. 1-2 ...) Wenlock Beds .| Dudley ......... 239
—— deflexa, PI. vii. fig. 7 ......... LS aie: LeU: } Do. & Walsall] 239
Hughesi. PI. viii. figs. 4,5 .| Silurian ......... Warious: c2s-.cc| 1242

De Ny dons] ne DOT a

Vill FOSSILS DESCRIBED AND FIGURED.

Name of Species. Formation. Locality. Page

TRILOBITA (continued).

Ampyzx binedulosus. Pl. xxi. fig. 1] ) ( 409

Cheirurus keisleyensis. Pl. xx.
MS WA EO NOCIO Pane ssn bs ee vansensan 417
(Pseudospherexochus) sub-
quadratus. Pl. xx. figs. 10 & 11. 421
— (?) Harknessi, Pl. xxi. fig. 2. 435
Cyphaspis ( Tornquistia) Nicholson.
PKR MES. Se OM, c.s.n0ndeesncins 433
Wonpes, spa. | Plixx, fig. 4 ...... 436 ©
PES TOnGes wee XA GOD rc cous : : 436
Fe oiaih var. brevicapita- pitereley nee Keisley \...2.288 {
ISS LENG OR CA SARE ee ee his cau eo | 412
, var. dongicapitatus. Pl.
SPT ee a cg Sosa Sabo w anleis @ vis Nictetgniciod | 412
gdleatus, Pl. xx. figs. 1-3 ... 414
50), Sele. Go 1p ee eae 416
Lichas bifurcatus. Pl. xxi. fig. 7 . 431
bulbiceps. Pl. xxi. figs. 8 &
PEE Soo vn coc tsde daaeosestabmees 428
— conformis, var. Keisleyensis. |
eRe LO scevcnivoneassarveenes J | 427
Ogygia marginata, Pl. xxvi. figs.| )
Mp AOPECE ED. avons sitsusarseductoaseds 538
MEDD co nce es] pEremadoe Slates] | Casrmarthen .. 537

Peltura punctata, Pl. xxvi. figs. 1-| |
10

Heinen eee creel ei ieeccstens | 535
Spherexochus latirugatus. Pl. xx.| Keisley Lime- :
Pai ee asc ecw tdsc ope denis owned stONa> .25E06.6 | Keisley ......... 423
Macrvra.
oo cai Whiteavesii. Figs. ‘|} Caeieentas Geil | here 293
BRACHYURA.
Hemolopsis Richardsom. Fig. 3... f Runes Charo 994
Paleocorystes Harveyi. Fig. 4 ...|\Cretaceous...4/)~ 225
Plagiolophus vancouverensis. Figs.| | | ee |
BREE O Bese sao: sabe snmateey-teteas: J f ea al Peay
ANNELIDA.
Eunicites Reidie. FP. xxii. figs. 2,) Lower Carboni-| Halkin ass |
OP AMAIG Sac las ntocees Rebelo ekler ferous. GBI cn nenaataed . 448

FOSSILS DESCRIBED AND FIGURED. 1X

Name of Species. Formation. Locality. Page
BRACHIOPODA.
Crania, sp. Pl. x. figs. 9 &10 ...| ) | Mullacott ...... 270
Lingula mortensis, P1.x. figs. 1-5. 266
Orthis rustica, Pl. xi. figs. 7-10... } North Devon . { 268
Rhynchonella Lewisii (?). Pl. xi.
Bog, Tol Se aed eer ete ie Barricane ...... 268
Stricklandi(?). Pl. xi. fig. 11.) } Morte Slates .{| Mullacott ...... 268
ia Hamlingii. Pl. xi. figs.
Me ee ere lita aacinodsleastetau Barricane ......| 268
Pe naniisia lirata. Fig. 3 & pl.
MR OO ro. ns ciste canoes suie L Ilfracombe ...... 266
sp. Pl) xi. figs. 12&13...... baes Mullacott ...... 270

LAMELLIBRANCHIATA,

Aucella Keyserlingi. Pl. xxvii.
JNES5 3) Cra AR Ae a Tealby Series...) Claxby..... ye. 560

volgensis. Pl. xxvii-figs. la—c.| | 549
3 , var. radiata. BL XXVii. ee eueels | onsiogton we

eS 255) Ber ee Saat iF 550
Waieuia, sp. Pl. xi. fig. 18 ...:..... \ (le ebarricationvere.cc 269
Cardiola interrupta (?). Pl. xi. fig.| | |

RE ae scthdvobadessieanneenn< Mullacott ...... 270
Modiolopsis barricanensis. Pl, xi.| + Morte Slates . +

BIO NOM or ciscicc cise scene csi net | North Devon ...| 269
Pteringa mortensis, Pl. xi. figs.

PESTS Ii cst eBbesaiphto tab 5. paoaioiren' sk ) (|. -Mullacott ...... 269

GASTEROPODA.

Avellana, sp. ef. Humboldti.’ Pl. \ (

PRUE UO loc os cninicnsidodeine cpaee xt 93
Cerithiwm cuckhamsliense. P. iv. |

HUMMER Osi ceicais i oeicisnenalsedeccns sive 92

Saundersi. Pl. iv. fig. 12 ... | 92

Lampusia (?) sp. Pl. iv. figs, 13 |

OTA CLEC DBD Re ee 93
Pleurotomaria (Leptomaria) per- |

spectiva. Pl. iii. figs. 13, 14, & \ Chalk Rock...... Warlous)...-.bs.2: 4

PES Md oe doce tbe caves veces | 86
Trochus berocscirense. Pl. iv. figs.

IM 2c e Sees nies einen cos oes 88
— Schliitert. PI. iii. figs. 11 & |

| iccAvctonscoe CEA nee ee 88
Turbo Geinitzi. PI. iv. figs. 5-8... 88

gemmatus. PI. iv. figs. 9 &
LUNES otic cea ) L 89

x FOSSILS DESCRIBED AND FIGURED.

Name of Species. Formation. | Locality. | Page
SCAPHOPODA.
DET ETL Ghali Rock......| Various «om | 96
CEPHALOPODA.
Ammonoidea.
Ammonites (Acanthoceras) hippo-| | f
castanum, var. compressus. Pl. v.| | |
A ia een tne Se cice cS uin aie din ‘ Cenomanian..{ | Devon............ 157
— (—) pentagonus. Pl. v.| | | '
HIS MOC IE Se wcinayee cane nce <2 cee) sinc J || Lyme Regis...... 156
Baculites bohemicus. Pl. ii. figs.) | (
RCM Oe ch Ree reels tecnica odisiein ee sie 76
Crioceras ellipticum. PI. iii. figs.
UD rect tena eke bounce cecnaten ve 84
Heteroceras Reussianum. Pl. ii.| | |
AUS Gee ae eee «Accu sa bates ensies . | 94
PHL dis eed S |. tou \ Chalk Rock...... Various ..:ceeeee 1 75
Prionocyclus Neptuni. PI. ii. fig.
A Gcedel. cies Ar v7
Ptychoceras Smith. Pl. ii. figs. 1) | :

Ri Ree cian Decaiies Ahir be ctacbeccen + | “4
Scaphites Geinitzi. Pl. iii. figs. 57,| J | 81
Octopoda.

Calais Newboldi. PI. vi. ...........- | Cretaceous ...... | Lebanon.......... | 229
Teuthide.
Plesioteuthis Fraasii. Fig. ......... | Cretaceous ...... | Webanon . eee | 283
PLESIOSAURIA.
Plesiosaurus dolichodeirus. Fig. 1 ? ? 248

macrocephalus. Pl. ix....... MAG aceon ore so-...| Lyme Regis...... 246

EXPLANATION OF THE PLATES.

SKULL OF PLESIOSAURUS MACROCEPHALUS, Buckland, to illus-
trate Mr. C. W. Andrews’s paper on the Structure of the
PE FERTOSAPIAE OMe ee eens cise rete cet sanemechitaneecens 246

IX.

PLATE PacE

Microscopic sections of Banpep SERPENTINE and PARTIALLY

Ue MELTED HoRNBLENDE-SCHIST, to illustrate Prof. T. G.
Bonney’s paper on those rocks in the Lizard district ...... 17

IL-IV CuaLk Rock Mo.uuvsca, to illustrate Mr. Henry Woods's
re Papers Oy HOSE LOssIIS) oo pinta coeaganes sia serirelndaisgeh jones desees 68

CENOMANIAN Ammonites, to illustrate Messrs. A. J. Jukes-

Vv. Browne and W. Hill’s paper on the Stratigraphy and Palx-
Ontology OF that TORMIA GION 6) aonsamce ca adaeneeqosaneesedeeese aa 99

VI Catais NewBo1piI, to illustrate Dr. Henry Woodward’s paper
; OUR CNA MOSS eta tnainfo'eictocsingseaspiajcigan dicina sieeaisain aisieddeeoaeae es 229

VII. & f Brrriso Acipaspis, to illustrate Mr. Philip Lake’s paper on
VIII. the British Silurian Species of that genus ..................+6- 235

Pauzozoric Mouuvusca or Nortu Devon, to illustrate Dr.
Henry Hicks’s paper on the Morte Slates and Associated
Beds in North Devon and West Somerset ..............0e0000: 254

X. & XI.

NIFEROUS GLACIAL Breps At Baccuus Marsa, to illustrate
Prof. T. W. Edgeworth David’s paper on Evidences of
Glacial Action in Australia in Permo-Carboniferous time. 289

Microscopie sections of GRANoPHYRES wiTH Forztcn Incuv-
stons, to illustrate Mr. Alfred Harker'’s paper on those
rocks, modified by the Incorporation of Gabbro-fragments,
in Strath GSisye)) et is ser Pie eter suited ciselclavins a docGondensesews 320

XIII.

wn. See AND VERTICAL SECTIONS OF THE PERMO-CARBO-
XIV. |

{ Voucanic Neck at Stromo (Faur0z); PART oF VOLCANIC
Necs, Canna; Dtn Mor, Sanpay; Don Brag, SANDAY,
XV_-XIX.4 seen FROM THE SOUTH-WEST and seen FROM THE NorTH, to
illustrate Sir Archibald Geikie’s paper on the Tertiary
\ Basalt-plateaux of North-western Hurope.................006 331

XX. & { Trrnoprres rrow THE KeisLey Limestons, to illustrate Mr. F.
XXI. | R. Cowper Reed’s paper on the Fauna of that horizon ... 407

xii EXPLANATION OF THE PLATES.

PLATE PAGE

PEMMATITES CONSTIPATUS, Sp. nov., and
XXII.
EKunicites REIDIz, sp. noy.; and

XXIII. { Pauzacts, to illustrate Dr. G. J. Hinde’s paper on those =
L

SOIT Esau AA SRR Gros ka At a EE

GrotocicAL Map or tae Nerigusournoop or DoLGELLy,
XXIV to illustrate Messrs. P. Lake and 8. H. Reynolds's

: paper on the Lingula-Flags and Igneous Rocks of that
: DISORICE | ooccywicnepencomeecateasnckdensecess-se0so0esssacr 511

XXV ( GroLocicAL SKETCH-MAP OF THE NEIGHBOURHOOD OF a
ak MARTHEN ; and

CARMARTHEN TRILOBITES, to illustrate Miss M. C. Crosfield 7528
XXVI. and Miss E. G. Skeat’s paper on the Geology of that |
GUBEGICLS eam ee ser tcc erences cn seascebcnnesmnueinener ios eaneee J

AUCELLA VOLGENSIS AND AUCELLA KEYSERLINGI, to illustrate
XXVII. Prof. A. P. Pavlow’s paper on the Classification of the
Strata between the Kimeridgian and the Aptian............ 542

Microscopic sections of LavAs AnD ASHES FROM THE KILDARE
XXVIII. InuteR, to illustrate Messrs. 8. H. Reynolds and C, I.
Gardiner’s paper on the above-mentioned Inlier ............ 587

‘GEOLOGICAL SKETCH-MAP OF PORTIONS OF IpAno, Montana,

AND WyominG, showing in part the Distribution of the

XXIX.{ Volcanic Rocks, to illustrate Prof. J. P. Iddings’s paper on
| Hxtrusive and Intrusive Igneous Rocks as Products of

\OP Mag mintie WimeremblatlOn ...-..0 0.00.00. ences. e+e coder eeeeeeee 606
SeismicaL Maps or THE Britisu Istes, tHE Inp‘An EMpiRe,
XXX.-— AFRICA, AND THE Lesser ANTILLES, to illustrate M. F. de
XXXIII. Montessus de Ballore’s paper on Seismic Phenomena in
Ge SUIS MAURO Soe cate mete celine) ob psieineikie nincinjee + wei Ee 651

Grotocican Mars or NortH-western Europe and the Crag

XXXIV. & District oF SuFFOLK AND Norro.k, to illustrate Mr. F.

XXXY. W. Harmer’s paper on the Pliocene Deposits of Holland,
(EL eet OS ic. eho, Le A ORE 748

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES

BESIDES THOSE IN THE PLATES.

FIG.

PAGE
1. Sketch-map of the north-western quadrant of Mont Jovet...... 5
9 Sketch of Dolomite-outlier at the foot of the western end of

WOE rt Gest A EMEA a aeaies Osis den ctcte cenafan ate sabe anidh tcsssrkaes 7
fee section near Watendlath: Varn io .oncedennasecesenuvenadss0nsacveee 13
Dome echion across Hard Warn 5.22.5 ).h ane-cctnascidcce< dana idecdsda.cece 14
ome eatte Onder e Wael odin te ac sacanietcuiravcauwiagaysteeasaicarsan cheviehends Se 14
1, { One of four ‘ eyes’ in hornblende-schist, north of Porthoustock .
: IME wanton sono jsut at Moca= «sloadueduidccamdeanyiakacnaesapeadesscuesecases, 19
Pam VerGh NOmABleMGtte, COA. oa. ducmcacaae napa t see encensks ddan sabe adhoc 20
3. Granulite included in serpentine, east of the Lion Rock......... 27
4 Serpentine adhering to a ‘step’ of granulite, in Polbarrow
; eee ck eet cats eae cutchss ce nlsng Seca sists vemenneriiessedeslactes 29
5. Banded granulite, south of Poltesco Cove ...............ceeceeseeees 29

6, 7. Serpentine and banded granulite, Enys Head ..................... 30
8. Do. Do... Polbarrow Cove) «.....5..:.. 30
9. Banded hornblende-schist in serpentine, Potstone Point......... 32

Intercalation of serpentine and hornblende-schist, gully north
10. ‘
PUL CIRC DI as Pe Re = Se ne eee 30
Gabbro included in granular dolerite, south of Porthoustock
Le
aA RS eR tee eet ecl sbi toes nee Sac ceuichele sac tceanbomctncecleveeecsens 43

Diagram showing the expansion of the Cenomanian of Devon
at Beer Head and Hooken Chiff

X1V PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.
FIG. PAGE
Tabular view of South-coast Sections ..............-2-00 facing 114
Section of the cliffs at La Héve, below the Cenomanian ......... 119

Sections of the Cenomanian at Brunval, St. Jouin, and La
MG VG 9 od ee cnhaseecaven-aoscisceeatiner esol Reuutcasscees saneasis facing 124

Comparison of English'and French Sections ............ facing 172
Sketch-map of the Yorkshire and Lincolnshire Wolds

Diagram showing the Correlation of the Speeton Series in

Workehire and Dincolmehire els. se ls.t 6 aces thes cesevee facing 212

aoa) Calhanassa WIMLEGUESIT, BD: NOV: cc 0c. nea sneoe+s vsannces eee 223
3: Aomolopsts Titehasgsont, 8. Ove 4 sis. .ee bec sleds -/0: <n0ceadcoede eee 224.
A.) Paleocorysces TArVEy1, Sp. WOVs A.ioenscdcestsscasncsesceasceot eee 226
5, 6. Plagiolophus vancowverensis, SP. NOV..0..2..0+0+00000s00soea0esseeenes 227
PIESiOTAULHAS ERGOST, (SP MOVE eectei<-qeeneece.-0s-p02+ + 0oe0o see 233

1. Palatal Surface of the Skull of Plesiosaurus dolichodeirus ...... 248
2. Diagrammatic figure of the Plesiosaurian palate .................. 251
Geological Map of a Portion of North Devon .................600 259

1. Section from near Morthoe to Woolacombe ..............sesseeeees 260
2. Section from Capstone Point, Ilfracombe, to West Down ...... 263

3. Impression of Stricklandinia lirata from Mullacott Quarry ... 267
Map of the District south of Conway...............cs.ssceessecesesee 274
Awe ea Seeisore aia, tS ADOVS WISHTICE. ccs aacsecoceve0 sien sadinbas onecclee eee 277

Glaciated Boulder from the Permo-Carboniferous of Dunbar,
near Bacchus Marsh (Victoria)

Coeeeeeorsceteeceesesteesesessesese

i2, Sections mart inf League Hole ......500....0.secnes.cseesasensar eee 303
3, Section in the little headland, near League Hole ...............--- 304
4. Patches of Chalky Boulder Clay in red clay, near Willow

Pride (OOCKHELG.. 6222s enssaewe ste sep vccueseningeeesn<osienreeen eenEeEEe 305
i Pterskereh at Gebel Adm. cc. ccn-saptieccesdanvtonescwonednedawaceer he eeemee 310
9 re unction of granite and Nubian Sandstone, near the barracks,
SO sob *ABSM AS. esa sd se olhen view » omewinwbioiasivisdlelel'n\ a6 n(e/=nie meee EEE
3s Se ChiOn ata larsiniit Ul wt USL SEE Secu cstedoinclsnatiless wcceesibe cee ot mene 313
4, Terrace of old Nile mud near Kom Ombo ............00.seeeceees 314
5. Section opposite the Island of Sehél at the First Cataract ...... 317
Geological Sketch-map of part of Strath (Skye) ...........-.....- 321
it heres: of scoriaceous and prismatic basalts at Camas Thar-
benmish se cocseeuscne eee Noe pene eet eects) asst tetera 334

——

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES. XV

FIG.

PAGE
2. Banded amygdaloidal basalt, Macleod’s Maidens (Skye)......... 336
3, 4,5. Lenticular lavas in Sando, Hesto, and Svino (Faeroe)............ 338
Gre, Section) at: Hrodbonypi(SuderG)\ vec cevcccocecesccueeesnesdoneseacconses 340
- Intercalated group of strata between basalts, An Ceannaich
; (BGO oases oataacs stata cues saat somes io Seiicddnies'ah tte eldaaaniryy somes 341
8. Section of volcanic neck at Strom (Vaagofjord) ................+ 344
9,10. Sections of volcanic rocks near the preceding ............... 345, 346
W Section of volcanic vent, Scorr, Camas Garbh, Portree Bay
Eye eesti a eee Cee a dat olardetiay whe amete wate dab dawos 347
2 Section of volcanic series at Ach na Hannait, south of Portree
; (Shaye ieee aut oon ssweateeenaorte buat ish ®. bi Ra laa ae 300
13 Columnar basalt invading agglomerate of volcanic vent,
3 Warcewonm Mor (Cama io. saen een tacagesqiet cones anita edathaeae 303

14, Columnar basalt invading conglomerate, Alman Islet (Canna).. 353

15. Section of cliffs below Compass Hill (Canna)

Pe AN eee eee 30D

i Gade cutting out conglomerate and shale, on shore below
Canna, POUSes sasaciscos 5.52/22. PEs Menge se nouns tan deen ava 361
17. Section of shales, tuffs, etc., Cul nam Marbh (Canna) ............ 362
fej section: of eastern front of Din Beag’ <...5..00. 12050. 62ssscdsene se: 367
19. Enlarged section on western side of same ...............s.eeeeceeeee 368

20. [Sian sill intrusive in Jurassic strata east of Kilmartin,
droptenmisiy (Slave) sence ges. occ tdaate Sine o won ccven odo gemet ean 374

91. a in cliff north of Ach na Hannait, between Portree Bay
aide Mock) Sueachany (SIGE) 0a. bceceusccunateecs -katinatsnacien se aloass se 375
22. Upper part of sill in Moonen Bay, Waternish (Skye) ............ 307
23. Dolerite-sill cut by another sill, Rudh’ an Iasgaich, Sleat (Skye) 380
24, Sill traversing bedded basalts, Strom6 (Vaagofjord)............... 380
25. View of the same, seen from channel opposite Kolter Island ... 381
Bow Ground-plan of dyke, ‘Torri! (Skye) (-..4-2s.0001-4-.- dene ersonace+on 382
27. Basalt-veins traversing granophyre, St. Kilda ..................... 383
28. Pale granophyre injected into dark basalt, St. Kilda ............ 392
29. Compound dyke, Market Stance, Broadford (Skye) ............... 394
30. Granophyre-sill resting on Lower Lias shales ..................465 395

31. Reversed fault, eastern side of Svind (FaerGe) .............0668 oe 402

xvi

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.

FIG. PAGE
32. Reversed fault, N.E. headland of Sando (FaerGe)...............06 402
Map of Barry Island and neighbourhood .................ssceeeeees 475
Section through Barry Extension Dock .............s.ceeseeeeeeeeees 478
1. | Vertical section at Allenton, Derby | j.00-2. <sic.<sliso0eene ae eeeeeeeee 498
2. Map of Allenton and neighbourhood .................0ee0e0 facing 502
3 hae through Allenton terrace, Sinfin Moor, and the River

‘ WRONG. ected bts op wie sle hate diabine siaeindcd ols nome'auewie se) deldstee eee 502
4, Interglacial river-gravel, Alvaston, Derby ...................c0ceeees 503
5. High-level river-gravel, Weston-on-Trent ..............c.cseceeeeees 507
1,2. Sections east and west of the Dolgelly Fault ....................008: 520
1. Map) of the Zirich Valley 1.005005. :s0.s0s0ssedunantesoe sane eee 558
2. Map of the Baden and Turei Basins ....0.-...ecesmseeeeeee ied ae 561
eS usection at Hichthal, Baden: ....-«csecc«ssesncecseemenee _ aut eee Renee 562
4. Section at Wettingen, near the upper viaduct ..................06+ 563
5. Section in the Kiissnacht ravine ......>..<n.0asneseeesmadeeee eee 566
BT USEEEGOMUGE GAM. dcx «aiBeais/ac.cds condom ene tehb rook somleeh aaae ene aaa 567
7 Section at Altschloss, near Wadenswil ............scsssssccnsseesens 569
8. Map of the Schindelleggi District. .......-..00--sa.ccassossheneeeeeee 570
9. Section at Kaltboden, near Schindellegei ...............ccceeee eee ee nis

10. Molasse-depression and moraine-wall between Etzel and Hohe .
FE WOMOM) wdc cas conscascessesacvadelesss eeo@e bias Sndseactieens Sea —eee eee 572
11. Transverse section of Sihl Valley at Schindelleggi ............... 573
12. Profile of the Ziirich Valley (Limmat and Linth) ............... 577
13-16. ‘Transverse sections of the Ziirich Valley ............seccecsesseesee 579
1) Manor the Kildare Inlier .........0.00¢..00..esseeeseeses ee 588
2. Map of central portion of Kildare Inlier ..................02seceeee 590
a esection across ‘Grange Hall .......1....0:00-ceossedeceeue eee eee eee 590
4.” Section. across the Chair of Kildare’ ..:.:./.:...J0.2+.s eee 591
5. Microscopic section of Hornblende-andesite, Hill of Allen ...... 602
13. Sections at, Carer Onen (Anglesey) ........<..+10aesswereonuctee eee 619
4, Holded bedding in'slafes, 202d. . 2.....-.04s.+-en-ssnnarthe eee eee eee 20
5. ape a section of grit with sponge-spicules, from Careg ae

RIOIN Le cece ica orce stat nisabaissiea lat “Ans tea tain s+ se er

PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES. XVil

FIG. PAGH
6. Slates underlying Ordovician shales at Oareg Onen ............... 621
7,8. Sections in the Baron Hill Group, Anglesey ....................0008 624
SIME AECL OMaC IIE OC ou Seat ea ane heat We act capella thes ds sae 625

10. Microscopic section of mylonitic seam in Tairffynnon breccia... 626

11. Section at northern end of Bryn Poeth Quarry..............sseee0 627
12. Were bee section of felspar-tuff below pisolitic ironstone,

rsyaw, AOOtI wanaennsattaneactece dete ete ceeie cate ed daca aston vuseh sa 627

1. Gneisso-granitic complex, Rudha Ghoiridh, Portskerry ......... 640

2. Part of base of great sill, Strathy Bay. ....../.......c0cseceesceenes 641

3 Foliated granite and biotite-gneiss, Allt Tom na Bradh, Kin-
: WU ACOprecasctan nica wees atenc cass hte tect eaiice ss seein Creve neanetatads 644

Inclusions of hornblende-schist in foliated granite, Altiphurst,
°| Strathy Point

PorslCeocaeeFSsaaevesHHGFSesanserGFe2ven2o20R2e 020 Ce8 es0020808

5.6 es of granite and pegmatite in hornblende-schist, N.B.

Conners Of Armadale: Bays ten isecs.cctecsicamecerseednsueeanddeessauhe: 647

i) Seismical map of the British Usleg 2.0.2.0 0.0... ccceseeeceecesceceee: 654

Pee scismical Map Ol Assay 6. usuteccecaateesses.tscesrdouweuctescvvacces 657

Soseismical map of New Zealand s..25.6..502 co. .oe.ccsececesceseeeses 660

4, Seismical map of Australia and Tasmania ..................c0eees 662

5, -Seismical map of British Columbia .............c.sesscceaseaceecees 663

6. Seismical map of Canada, New Brunswick, and Nova Scotia... 664

7,8. Seismical maps of Malta and Cyprus esteseertsesessseetessesees 666

9,10. Seismical maps of Jamaica and British Honduras .............. 667
11, 12, & { Seismical maps of British Guiana, Chatham Island, and the

13 { I SEriiUel ar lSlaROS Neen. se triercs.de ccenea ve senietustesvacudeeusncacOas: 668

Diagrammatic section of Dundry Hill .............. tices eee 695

Geological map of Dundry Hill .........6. 162 sceceeseeesessccncdeecees 715

Pee Oiaeram: of Promeodal terrace ..sc.0ce0ss ec .cencvacasrnesesssesees 722

2. Terraces across the mouth of the Gosina River .................. 725

3. View on the Ukanskoe River, Kola Peninsula ..................00. 727

4. General view of the boulder-covered area, Sviatoi Nos ......... 728

6 { Ukankoe River soning ee Mea ceediiscis aes Neer : ; 728

6 wee section of boulders in hollows, neighbourhood
See TAL OP NOSE (easier sicancnessceitseredssdaentesrtctevecwaders cos ens 729

VOL. LII. b

- Xvi PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES.

FIG. PAGE
7. Tundra, with boulders, neighbourhood of Ukanskoe River...... 730
8. Sketch of Gooseland, Novaya Zemlya ..........sscssccseccsccsccoecens 733 ~

g_ { Islands in Kostin Schar, connected by a glaciated ridge, covered
{ With Shinglo ......0:-0..e0ssecssceanecn ence eceaseee teehee eee 734

10. View on the Neckwatowa River, Novaya Zemlya

11. Diagrammatic section at the head of Green Harbour, Spitsbergen 739

1. Section from Sutton to Yarmouth ...............00. csccecccocscccees 751

2. Section from Norwich to Yarmouth ............ccccecccceccecceceees 7538

8. Section from Norwich to Greenlo ..........ccccseccccceccceececencecs 753

4, Section from Cassel to Amsterdam..... ......sccscsccccccecceccecsees 761
CORRIGENDA.

Page vi, lines 5-8 from top, insert a query after each of the species mentioned
as occurring in the Olenellus-zone at Nuneaton.

Page 201, top line, before ‘few’ cnsert ‘a.

Page 487, 12th line from bottom, read ‘ Dendrophrya’ for ‘ Dendrophyra.’

. Page 487, 14th line from bottom, read ‘? Dendrophrya’ for ‘ Dendrophora.’

No. 205.

GEOLOGICAL SOCIETY.

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THE GEOLOGICAL SOCIETY OF LONDON.

Vout. LILI.

1. The ‘ ScuistEs Lustris of Mont Jovet (Savoy).
By J. W. Gregory, D.Sc., F.G.S. (Read November 6th, 1895.)

Tue controversy as to the age and origin of the ‘ Schistes lustrés ’
of the Western Alps has passed through three distinct stages. At
the beginning of the century these schists were included among the
primitive rocks. ven in the first decade, however, this idea was
refuted in a paper by Brochant,' which may still be read with
interest, owing to its excellent description of the physical features of
the Tarentaise. In this work, all the rocks of which Mont Jovet is
composed, with the exception only of the gypsum, were referred to
a series of ‘ terrains de transition,’ intermediate between the crys-
talline primitive rocks and the normal, secondary, stratified deposits.
Fifteen years later, a further advance was made, which restricted
the ‘terrains primitifs’ within still narrower limits. Bakewell?
then showed that the gypsums of Mont Jovet were regularly inter-
stratified with the limestones; moreover, as he correlated the
anthracitic beds with the English Coal Measures, he included the
limestones in the ‘upper secondary strata,’ meaning thereby the
Permian and the Mesozoic. A second stage in the controversy was
entered upon with Elie de Beaumont’s * epoch-making discovery of
belemnites in the limestones of Petit-Cceur, a hamlet 5 miles north-

* A.J. M. Brochant, ‘ Observations géologiques sur des terrains de transition
qui se rencontrent dans la Tarentaise et autres parties de la chaine des Alpes,’
Journ. des Mines, vol. xxiii. (1808) pp. 321-380.

* R. Bakewell, ‘Travels...in the Tarentaise and various parts of the
Grecian and Pennine Alps in the years 1820-1822,’ London, 1823, vol. i.
pp- 295-300.

° Elie de Beaumont, ‘Notice sur un Gisement de Végétaux fossiles et de
Bélemmnites, situé a Petit-Ceur prés Moutiers, en Tarentaise,’ Ann. Sci. Nat.
vol. xiv. (1828) pp. 113-127.

Q.J.G.8. No. 205. B

2 DR. J. W. GREGORY ON THE ‘ SCHISTES [Feb. 1896,

west of Mont Jovet. In consequence of this, Fournet,’ in his map,
marked the whole of the rocks of the mountain as Jurassic ; while,
later on, Lory,’ who knew the locality well, identified the schists
and limestones of the summits as altered Trias. In spite of the
protests of the Italian geologists, who referred the ‘ Schistes lustrés”
either to the early Paleozoic * or to the Archean erystalline series,”
the weight of Lory’s influence gained general acceptance for his
view. It was not till 1887 and 1889 that Zaccagna’ and Bonney °
carried the controversy into the third phase by the independent
description of some sections across the Cottian Alps, which showed
a marked unconformity between the Trias and the ‘ schistes lustrés,’
and thus proved the pre-Mesozoic age of the latter.

These two papers both described areas which Lory had previously
mapped, and on which he rested his conclusions. In spite, there-
fore, of the clearness of the descriptions of the two authors, their
conclusions have not been generally accepted. The official map of
the French Geological Survey on the seale of 1:1000,000, issued
in 1889, is coloured in accordance with Lory’s views. Diener,’
though accepting most of the ‘ Kalkschiefer’ (or ‘ schistes lustrés ’)
as pre-Mesozoic, still includes part of them in the Trias. Kilian,”
in his lucid and judicious discussion of the question, holds that as
the presence of these schists seems to exclude that of the Carboni-
ferous, it is possible that they are the altered representatives of the
rocks of this system. Parona’s® discovery of radiolaria in the
schists in the typical sections near Cesana has thrown further doubt
on the Archean age of the beds ; while, still more recently, Marcel
Bertrand * has gone back unreservedly to the theory of the Mesozoic
age of the ‘ schistes lustrés.’

* J. Fournet, ‘ Mémoire sur la Géologie de la partie des Alpes comprise
entre le Valais et |’Oisans,’ Ann. Soc. roy. Agric. Lyon, ser. 2, vol. i. (1849)
pp. 201-202, pl. i.

2 ©. Lory, ‘ Description géologique du Dauphiné,’ Bull. Soc. Stat. Isére,
ser. 2, vol. vii. (1864) p. 16; ‘Carte géologique de la Maurienne et de la
Tarantaise (Savoie),’ Bull. Soc. géol. France, ser. 2, vol. xxiii. (1866) p. 481 ;
‘Sur la Constitution et la Structure des Massifs de Schistes cristallins des Alpes
occidentales,’ Compt. Rend. Congrés Géol. Internat. sess. 4 (Londres, 1888), p. 93.

° As, e. g., B. Gastaldi, ‘Studii geologici sulle Alpi occidentali, pt. i., Mem.
descriz. Carta geol. Italia, vol. i. (1871) pp. 16-19.

* As, e. g., M. Baretti, ‘Studi geologici sulle Alpi Graie settenttionali,’
Mem. R. Accad. Line. ser. 3, vol. iii. (1879) pp. 484-486, pl. i.

° D, Zaccagna, ‘Sulla Geologia delle Alpi occidentali,’ Boll. R. Com. geol.
Ital. vol. xviii. (1887) pp. 346-417, pls. ix.—xi.

6 T. G. Bonney, ‘ Notes on Two Traverses of the Crystalline Rocks of the -
Alps,’ Quart. Journ. Geol. Soc. vol. xlv. (1889) pp. 67-109.

7 Diener, ‘ Gebirgsbau der Westalpen’, Vienna, 1891, p. 103.

° W. Kilian, ‘ Notes sur Histoire et la Structure géologique des Chaines
alpines de la Maurienne, du Briangonnais et des Régions adjacentes,’ Bull.
Soc. géol. France, ser. 3, vol. xix. (1891) pp. 579-580.

° C. F. Parona, ‘ Sugli Schisti silicei e radiolarie di Cesana presso il Mon-
ginevra, Atti R. Accad. Sci. Torino, vol. xxvii. (1891-92) pp. 805-319.

10 Marcel Bertrand, ‘ Etudes dans les Alpes Frangaises.—Structure en Even-
tail, Massifs amygdaloides et Métamorphisme,’ Bull. Soe. géol. France, ser. 3,
vol. xxii. (1894) pp. 69-118, pls. iv.—vi.; ‘Schistes lustrés de la Zone centrale,’
ibid. pp. 119-162, pl. vii.

Vol. 52.] LUSTRES ’ OF MONT JOVET (SAVOY). 3

This divergence of view is doubtless due in part to the fact that
the ‘schistes lustrés’ cover a considerable extent of country, and
the different theories rest on the interpretation of different sections.
Fortunately, however, Zaccagna ‘ and Bertrand * have both recently
described Mont Jovet, and each claims that it supports the two
rival theories.”

Mont Jovet has long done service in geological controversy, as it
is situated close to Moutiers, where a school of mining flourished at
the beginning of the century. Its structure was investigated then,
and it has been repeatedly revisited. Fournet in 1849 claimed it
all as altered Jurassic; while Lory, who worked over it with care,
identified the rocks of the central group of peaks as part of his
‘schistes lustrés calcareo-talqueux du Queyras et des vallées
piémontaises,’ and therefore as Triassic. Favre," who briefly de-
scribed the mountain in 1867, suggested that the limestones of this
series might be Jurassic. Zaccagna, like Lory, accepted the central
rocks as * schistes lustrés,’ but he gave a section across the mountain,
showing a marked unconformity between these and both the Trias
and the Carboniferous. He therefore regarded the mountain as ‘an
isolated outskirt of the Upper Archzean zone which rises through
the stratified rocks between the Isére and the Doron, and which,
being constituted of calc-schists, has been hitherto united to the
Triassic formation. It was probably part of the eastern covering of
the zone of lower crystalline schists which passes to Cévins, being
united in a synclinal to the cale-schists, which ought also to cover
the western side of the nucleus of the Vanoise.’ ’

Bertrand, on the contrary, describes the mountain as having
exactly the opposite structure. According to him it is ‘un noyau
synclinal ouvert entre les deux branches étirées d'un méme pli
anticlinal’ (op. cit.p. 100). Or, as he concludes elsewhere (p. 125),
although there are some uncertainties, ‘there is no doubt that it is
impossible to claim that one can see there a Paleozoic island, for it
is in fact a paquet of Lias, perhaps with Triassic schists at the base,
placed on the summit of the fan.’

Practically the two observers simply invert the mountain. The
central rock which forms the summit, according to Zaccagna, is an
Archean schist; according to Bertrand, it is a Liassic limestone
identical, save for the absence of belemnites, with the adjoining
flags with Belemnites truncatus (op. cit. p. 124). According to
Zaccagna the rocks of the summit are an island, on the flanks of
which the Triassic and Carboniferous beds were unconformably
deposited; according to Bertrand the rocks of the summit were

' D. Zaccagna, ‘Riassunto di Osservazioni geologiche fatte sul versante
occidentale delle Alpi Graie, Boll. R. Com. geol. Ital. vol. xxiii. (1892)
pp. 229-231, 396-397. 2 M. Bertrand, op. jam eit.

3 For an abstract of these two papers, see J. W. Gregory, * Recent Contri-
butions to the Geology of the Western Alps,’ Science Progress, vol. iii. (1895)
pp. 147-174.

* A. Favre, ‘ Recherches géologiques dans les parties de la Savoie, du
Piémont et de la Suisse voisines du Mont Blane,’ vol. iii. (1867) pp. 280-231.

> Zaccagna, op. vit. (1892) p. 397, & pl. v. sect. 2.

B2

4 DR. J. W. GREGORY ON THE ‘ SCHISTES [Feb. 1896,

laid down later, and upon the others. In fact, what according to
Zaccagna is the oldest rock in the mountain, according to Bertrand
is the newest.

The differences, moreover, are as important as they are absolute.
According to Bertrand, the ‘ schistes lustrés’ pass laterally into the
Trias (see op. cit. fig. 2, p. 128, and fig. 9, p. 135). According to
Kilian the presence of the ‘ schistes lustrés’ seems to exclude the
presence of the Carboniferous, and he therefore suggests that the
‘schistes ’ may be Carboniferous; though he admits that this cannot
be definitely determined. If, however, Zaccagna and Lory be correct,
and the central rocks of Mont Jovet are ‘schistes lustrés, then these
occur surrounded by both Carboniferous and Triassic rocks. In
that case, it cannot be maintained that the ‘ schistes lustrés’ are
the eastern metamorphosed condition of the beds which farther
west have remained as non-foliated sediments.

The identification of any ‘ schistes lustrés’ in Mont Jovet would
therefore alone be fatal to the view that these rocks are Carboni-
ferous or post-Carboniferous in age. Having failed on previous
occasions to obtain definite proofs of the pre-Carboniferous age of
the ‘schistes lustrés’ in the Cottian Alps, I was the more im-
pressed by Bertrand’s reversion to Lory’s theory. The perusal of
Bertrand’s paper did not carry conviction ; but respect for the
care and ingenuity with which the author had solved the puzzling
problems of Provencal geology necessitated the careful consideration
of his views. I therefore resolved to visit Mont Jovet as soon as
the melting of the snow rendered geological work possible, and exa-
' mine the mountain independently in order to see whether it does
contain any ‘ schistes lustrés’; and, if so, to try to construct a more
detailed geological map than has yet been published... So much,
however, of the mountain is covered by pine-forest and talus, by
moraine and meadow, and so many of the important junction-lines
are thus hidden, that it was impossible to make a geological map
sufficiently complete to repay the time which it would occupy. I had
therefore to be content with a sketch-map based on the French
Ordnance survey on the scale of 1: 80,000}

Standing on the hills on the northern side of the Isére, at any
good point of view between Moutiers and Aime, the southern side
of the valley is seen to consist of three main divisions. The lowest
part is formed of steep cliffs of dark-coloured rocks, covered by
vineyards, meadows, and woods. Above this is a belt of pine-forest ;
in this occur at intervals cliffs of buff dolomite and white gypsum,
and occasional crags and pinnacles of the former rock. Above this
belt are the high-level pastures, formed of undulating meadow-land
passing up into irregular rock-strewn slopes, and a group of peaks,
of which the highest is Mont Jovet. Further examination of this
mountain-mass shows that these three zones are each formed by
different series of deposits. The lower slopes are occupied by Car-

1 Albertville, S.E. feuille 169 dis, type 1889,

Vol. 52.| LUSTRES ’ OF MONT JOVET (SAVOY). 5

boniferous; the cliffs above by Triassic dolomites and gypsums;
the highest meadows and the central peaks by the rocks whose
age is in dispute.

The area more especially examined was the north-western
quadrant of the mountain, which is included in the sketch-map, fig. 1.

Fig. 1.—Sketch-map of the north-western quadrant of Mont Jovet.

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| Heights in metres. » ede

| Zar rias. EEE Carboniferous. = pentine, fs sees praghivzestone Fen] Overtzttes &c

Lustrés. in Schistes in Schistes
| Lustrés, Lustres.

as: Dee : F
Seale : 30,000 792 inch to the mile.

The Carboniferous rocks are of the ordinary type of this series in
the Tarentaise ; good sections and exposures can be seen on the
banks of the Isere, and around the hamlets of Hauteville and Notre
Dame du Pré, at the height of 2500 feet above the floor of the
valley. The superposition of the Triassic rocks to these can be
clearly seen around the latter village, for the Carboniferous beds
there form a platform upon which the Triassic limestones rest.

It is unnecessary to give any description of the characters of the
Carboniferous and Triassic rocks, but those of the third series
require more careful notice. For the question as to whether or no
these are part of the ‘ schistes lustrés’ can be determined by litho-
logical evidence alone.

The rocks in question consist of three main types: 1st. A series

6 THE ‘ SCHISTES LUSTRES’ OF MONT JOVET (SAVOY). [Feb. 1896.

of limestones sometimes massive, sometimes passing into calc-schists,
the beds of which are separated by beds of crushed phyllites ;
2nd, gritty quartzites and irregular quartzitic schists; and 3rd, talcose
lustrous schists. These three sets of rocks occupy the whole of the
central part of the mountain, including the summit of Mont
Jovet and the four subordinate peaks, namely, the Grande Cote
(2543 metres), La Cote (2058 m.), Mont des Arrhets (2440 m. and
2492 m.), and the ridge including the 2272 and 2370 metre-points
north of Mont Jovet, between the upper valleys of Nant de Thionet
and the Vallon des Frasses. The main problem is the relation
of this group of rocks to the Trias upon its margin.

The position of the junction of the Triassic limestones and the
ike of this central series, or, as we may at once, for convenience,
call them, the ‘schist series,’ can be easily determined to within a
few yards. The actual junctions, however, are hidden. I did not,
in fact, find a single case where, in a clear cliff-section, the actual
superposition of the two could be seen. In several points, as at the
junction of the gypsum and the schists in the hollow between the
2067 metre-point and the western end of the Mont des Arrhets, it
certainly appears as if the Trias underlay the schists; for the
apparent dip in the gypsum is to the south-east, and under the
schists, Itis not, however, certain that this bedding in the gypsum
is true stratification ; but even if this be so, the apparent super-
position can be explained as due to an overfold, or to the subsidence
of the limestones, owing to the solution of the gypsum along lines
of drainage. The latter cause has certainly rendered the apparent
dip in the gypsiferous beds very unreliable.

The most instructive case illustrating the relation of the two
series was found a little to the north-west of the western end of the
Mont des Arrhets. There occurs a hummock of the gypsiferous
part of the Trias, marked on the map as the 2067 metre-point. The
stratigraphical relations of this mass are clear, for the junction
between it and the schists can be traced all round, excepting for a
few yards on the north-eastern side. The evidence is sufficient to
show that this hillock is simply a mass of the Trias, left as an out-
lier on the flanks of a slope of schists.

The relations of this Trias are illustrated by the accompanying
sketch (fig. 2). ‘The fir-covered boss in the centre is the 2067 m.
point; the lower knoll to the left (the 1894 m. point) is the upper
termination of the main outcrop of the Trias. On the extreme
right is a low cliff of schist, which is part of the western end of the
Mont des Arrhets. The schists can also be seen in some low crags
on the eastern side of the valley, to the right of the 1894 m. hill.
They can moreover be traced over the whole of the grassy slope from
the end of the Mont des Arrhets, round the southern side of the
2067 metre-boss, to the valley to the west, and thence up the lower
part of the slope of the 1894 m. point. Fortunately, the ground
on the southern side of the 2067 m. point is moutonnée, and the
crests of the ridges either just reach the surface, or can be exposed
with but little trouble. It is thus possible to prove that the schists

Fig. 2.—Sketch of Dolomite-outlier at the foot of the western end of Mont des Arrhets (seen from the cow-chalets of
Notre Dame du Pré, looking northward),

Valley of Mont W. end of Mont
1894 metres. the Isere. Blane, 2057 metres. des Arrhets.

Trias, Schistes lustrés, Hummocek of Trias Schistes lustrés.
(schists in fore-
ground),

8 DR. J. W. GREGORY ON THE ‘ SCHISTES [ Feb. 1896,

are continuous from the end of the Mont des Arrhets, round the Trias
outlier, to the crags in the valley below, where they finally plunge
under the main sheet of Trias. On the northern side of this boss
of dolomite there is a very steep slope down to the Nant de Thionet.
The upper part of this slope is masked by pine-wood and talus, and
outcrops of rock im situ are very scarce. The complete isolation
of the limestone-boss cannot therefore be proved. The general
characters of the cliff to the north leave no doubt in my mind that
it is wholly formed of schists; all the exposures seen were of rocks
of this series, and these were sufficiently numerous to restrict the
possible connexions between the dolomite of the boss and that of
the cliffs below to a very narrow band. This band would run almost
at right angles to the strike of the schists, and thus can only have
been formed by deposition upon these. Its existence, therefore,
would strengthen the evidence in favour of the view that this
dolomite is an outlier from the limestones below, from which it has
been separated by denudation. In this case the sheet of limestone
of which it was once a part must have been deposited on the flanks
of the old schist series.

A second line of enquiry is as to the occurrence of fragments of
one formation in the other. It is natural to turn to this for assist-
ance, for one definite case would settle the question. In the schist
series there are some crushed grits which must formerly have been .
fine pebble-beds. I searched in these in vain for any fragments of
the dolomite. In the Trias there are bands of conglomerate,
crowded with included fragments, ‘The first of those examined was
at the Chalets du Préjordan; a small pit there yielded numerous
fragments of what appeared to be altered dolomitized specimens of
the limestones in the central schist series. I could not, however,
there find any unquestionable specimens of the ‘schistes lustrés’
themselves. At a point near Notre Dame du Pré more satisfactory
evidence was obtained. The Triassic dolomites there contain some
beds of pebbles, many of which appear to me to be unquestionable
fragments of the ‘ schistes lustrés.’ Some of these included frag-
ments may be matched exactly in the cliff of schists, just above the
bank of limestone in which the fragments occur.

A third line of argument may be based on the unaltered condition
of the Triassic rocks in contrast with those of the central schist series,
The Triassic dolomites show no sign whatever of foliation. Bertrand
has remarked the intensity of the puckering and folding of the rocks
of the centre of the massif, and admits that this is not easy of ex-
planation. Lory had previously recorded the occurrence of albite-
crystals in the limestones of the schist series, but regarded this as
only an illustration of the extent to which the Triassic rocks have
undergone alteration. If the metamorphism of the schists were
most strongly marked in the centre of the massif, and least so on
the margin, it might be explained as due to post-Triassic movements.
But this is not the case. The extent to which the rocks have been
rendered schistose depends on the character of the rocks and not on
their position. Some of the rocks in which the foliation is most marked
occur on the margin of the series within 10 yards of the dolomite.

Vol. 52.) | LUSTRES ’ OF MONT JOVET (SAVOY). 9

On the other hand, the member of the schist series which at first
sight appears least altered is the massive limestone of the Grande
Cote, nearly in the centre. Even between the least altered of the
limestones of the schist series and the Triassic dolomite there is a
great difference. Microscopic examination shows that the latter is
a normal dolomite, and does not contain any authigenous crystals
of albite. The limestones of the schist series, on the other hand,
are really calciphyres, show traces of intense crumpling, and con-
tain abundant crystals of plagioclase and epidote. If the schists be
really younger than the Trias, it appears inexplicable why these
should have been so intensely altered, while the dolomites in contact
with them should have escaped.

It is therefore contended that the evidence is conclusive that the
Triassic dolomites have been deposited unconformably on the edges
of an older series of schists. It remains now to consider what
evidence is available to determine with which member of the schist
series in the Western Alps these must be correlated. ‘The contorted,
lustrous, black, talecose schists which occur on the summit of Mont
Jovet remind one at once of the ‘schistes lustrés’ of the classical
area around Cesana, z. ¢. of the ‘ Kalkschiefer’ of Diener, the
‘Calcescisti’ of the Italian geologists, or the ‘Upper Archzean
schists’ of Prof. Bonney. Zaccagna—whose acquaintance with
these schists is intimate—has no hesitation in regarding these as
part of this series. Lory, who knew both series extremely well,
also unhesitatingly identified the Mont Jovet rocks as ‘schistes
lustrés.’

It must be admitted that in one respect these rocks are not typical
representatives of the ‘ schistes lustrés’ series, and that is the great
development of massive limestones and quartzitic beds. Bands of
the same character as these occur in the ‘ schistes lustrés ’ around
Cesana; but both the limestones and grits are there represented
by very thin layers and films, and the main mass of the formation
consists of black lustrous schists.

It is these massive limestones which Bertrand has assigned to
the Lias, and macroscopic examination of a specimen does not show
anything fatal to this view. Microscopic study, however, reveals
the fact that the rocks are entirely crystalline, and have undergone
intense alteration. Sections of specimens from a boss in the upper
part of the valley of the Nant Gelé, on the northern slope of the
Grande Cote, and from the summit of this peak, show that. they
consist in the main of crystalline, polysynthetically twinned calcite.
A black carbonaceous dust occurs in irregularly crumpled and broken
lines through the rock. Some small grains of plagioclase (deter-
mined by Lory as albite) are scattered in the calcite at irregular
intervals. Grains of epidote are fairly numerous. The rock is
therefore a calciphyre, and is very different in structure from the
Jurassic limestones of the neighbourhood.

' The black lustrous schists, with which these limestones are seen
to be interstratified both on the central peak of Mont Jovet and on
the flanks of the Grande Cote, are, however, thoroughly typical

10 DR. J. W. GREGORY ON THE ‘ SCHISTES [Feb. 1895,

‘schistes lustrés.’ A specimen collected on the western aréte of
Mont Jovet, just below the summit, agrees in its microscopic struc-
ture with the schists of the Cesana district. The microscope shows
that it consists of alternate layers of a black, indeterminate, and a
clear crystalline material. The rock is intensely crumpled, and the
black bands often thin out along lines of shear. A quarter-inch
objective resolves the black material into a very fine calcareous
and argillaceous dust, and the white clear layers into a mosaic of
quartz in which occur tiny crystals of white mica. There is no
sign of calcite in the rock, nor does it effervesce with acid. ‘The
rock, therefore, agrees exactly with one of the finer and non-
calcareous varieties of the ‘schistes lustrés’ of the Cottians.* It
appears to have been originally a fine-grained mudstone.

It may be suggested that possibly the ‘schistes lustrés’ and the
limestones are not part of the same series. But that they are so is
very clearly shown just below the summit of Mont Jovet. A few
yards along the ridge to the east a layer of limestone strikes right
across the ridge. Some rocky ribs run down the northern face at
this point, and in one of these, about 30 yards east of the summit,
the junction can be clearly seen. It could not be traced far, as
there was too much snow on this face of the mountain at the time
of my visit; but the exposures were sufficient to demonstrate the
interstratification of the limestones and the schists.

In spite, therefore, of the unusually extensive development in the
schist series of this massive non-foliated limestone, I feel bound to
admit that Lory and Zaccagna were right in identifying the central
rocks of Mont Jovet as ‘ schistes lustrés.’ There is nothing at all
improbable in the outcrop of these schists in Mont Jovet, if they be
pre-Carboniferous in age. This series is extensively developed 15
miles to the east and 20 miles to the south, and its extension thence
westward bclow the Carboniferous and Trias rocks, as suggested in
Zaccagna’s section,” is not in any way improbable.

Another feature which allies the rocks of Mont Jovet to the
erystalline schist series, is the occurrence in them of basic igneous
rocks of the ‘pietre verdi’ type. These have been recorded
on the mountain by Favre, as well as by Zaccagna and Bertrand.
A mass of serpentine occurs in the schists in the upper part of
the Vallon des Frasses: it appears almost identical with that
described by Bonney from the pass of Mont Genévre, which has been:
proved to be pre-Triassic.* I should be loth to use the characters
of intrusive igneous rocks as a proof of age, but the coincidence in
this case is significant.

1 It may be compared with Prof. Bonney's description of the microscopic
structure of the ‘schistes lustrés’ near Cesana, Quart. Journ. Geol. Soe. vol. xlv.
(1889) p. 103.

‘ 2 Zaccagna, ‘ Riassunto Osserv. Geol. Alpi Graie,’ Boll. R. Com. geol. Ital.
vol. xxiii. (1892) pl. v. sect. 2.

3 'T. G. Bonney, ‘Two Traverses, etc., Quart. Journ. Geol. Soc. vol. xlv.
(1889) p. 80; Cole and Gregory, ‘ Variolitic Rocks of Mont Genévre,’ 2bzd.
vol. xlvi. (1890) p. 805; Davies and Gregory, ‘ Geol. Monte Chaberton,’ zbid.
yol. 1. (1894) p. 307.

Vol. 52.] _ LUSTRES’ OF MONT JOVET (SAVOY)... 11

CoNCLUSIONS.

It is contended, on the evidence above cited, that Lory and Zaccagna
were right in identifying the central rocks of Mont Jovet as ‘ schistes
lustrés, for this conclusion is supported by their lithological cha--
racters and the nature of the igneous rocks associated with them,
and is not opposed to their stratigraphical relations.

It is further shown that the schists in question are older than
the Trias (1) by the occurrence of fragments of the schists in the
Trias; (2) by the discordance of strike between the two series;
(3) by the occurrence of masses of dolomite resting unconformably
on the flanks of the schists; and (4) by the fact. that the Trias
has escaped the metamorphism which the schists have undergone.

The probabilities are all in favour of the schists occupying the
same relation to the Carboniferous as they do to the Trias; while
the close approximation of the schists to the former show that the
schists are not the altered representatives of the Carboniferous,
We must therefore conclude that the ‘schistes lustrés’ are pre-
Carboniferous, but evidence by which finally to assign them to any
exact horizon before this date is still wanting.

Discussion,

Prof. Bonnry expressed his sense of the great value of Dr.
Gregory’s paper, which he regretted had been pushed into a corner
by the time which he had been obliged to take up for his own.
From his general knowledge of the district and intimate acquaintance
with other parts of the Alps, he had no doubt that Dr. Gregory was
quite right in his interpretation, and that the crystalline schists,
often called the ‘ schistes lustrés,’ were certainly pre-Carboniferous,
and probably much older.

Dr. Du Ricue Pretier fully agreed with Prof. Bonney’s remarks
as to the great importance of the subject dealt with in the paper,
and was gratified to see that the Author substantially endorsed the
views of Zaccagna, who had done so much excellent work in the
Western Alps from 1887 to 1889, and, by extending the survey on
the Italian side for fully 30 miles into the Vanoise district in
Savoy, as far as the valley of the Isére, had conclusively shown that
Lory’s views as to the Upper Triassic age of the calcareous schists,
or ‘ schistes lustrés,’ were utterly untenable, and, further, that the
bulk of the mica-schists referred to by Termier as Permian are also,
like the ‘schistes lustrés,’ pre-Carboniferous—indeed, of Archean
age. The speaker had visited the Savoy district some years ago, and,
in his opinion, the occurrence in the central mass of Mont Jovet of
serpentine, gabbro, and so-called green Alpine marble (as quarried
near the summit), under conditions strictly analogous to those on
the Italian side near Susa, and also in Liguria, affords a strong’
argument in favour of the Savoy ‘schistes lustrés’ being, like those
of the Italian localities, of Archean age.

The AvurHor replied, thanking the Fellows for their reception of
his paper.

12 MR. J. E, MARR ON THE TARNS OF LAKELAND. [Feb. 1896,

2. Avprtronat Notss on the Tarns of Laxetanp. By J. E. Marr,
Esq., M.A., F.R.S., Sec.G.8. (Read November 20th, 1895.)

Tue following notes form a supplement to a paper on ‘ The Tarns
of Lakeland’ read before the Society in 1894. I have had the
opportunity during the present summer of devoting more time to
the study of Watendlath Tarn, and have examined three other tarns
of some interest.

(a) Watendlath Tarn.

In my former paper, I stated that in the case of Watendlath
Tarn ‘a great mass of drift is plastered against the east side of the
valley, and may have filled the old valley. I. have since ascer-
tained that there is no old valley there, but that the solid rock runs
-all round the northern, eastern, and southern ends of the tarn:
I furthermore stated that ‘on mounting some way above the tarn
I saw indications of the possible existence of a moraine-filled
depression’ on the western side. J have now examined this de-
pression and satisfied myself that beneath it lies buried the old
valley, the stream from which ran down into Borrowdale near Ros-
thwaite—that is, about 3 miles south of the present junction of the
Watendlath valley with Rosthwaite, near Lowdore. ‘This moraine-
filled depression runs close to the path from Rosthwaite to Watendlath
Tarn. The watershed here is about 200 feet above the surface of
the tarn, and, as the tarn is 46 feet deep, it requires a barrier of
drift over 250 feet in thickness to account for the tarn; but, as the
valley is evidently a narrow one, and its course lay at right angles
to the direction of the ice, the occurrence of this somewhat thick
mass of drift presents no difficulty, and a much thicker mass has
been recorded in the neighbourhood filling up an old valley, as proved
by boring in Furness.

Proceeding from Rosthwaite towards the tarn, the path ascends
by the side of a stream running from Brund Fell to a spot called
Birkett’s Leap, where it leaves the main stream and is carried
parallel with a tributary descending from the lowest part of the
watershed. The stream from Brund Fell and the lower part of the
tributary stream have cut to a considerable depth between rock and
drift, the northern bank of the stream being composed of rock, and
the southern side of drift, so that the streams appear to be gradually
cutting out the old valley (see fig. 1). To the east of Birkett’s Leap,

* Quart. Journ. Geol. Soe. vol. li. (1895) p. 35. In this paper the following
errata occur :—

Page 39, last line, for ‘ Ask’ read ‘ Ark.’
, 42, line 7 from bottom, for ‘lower’ read ‘southern.’
» 42, line 8 from bottom, for ‘ upper’ read ‘ northern,’
» 44, line 7 from top, for ‘ east’ read ‘ west.’
», 40, line 5 from bottom, for ‘ east’ read ‘ west.’

Vol. 52.] MR. J. E. MARR ON THE TARNS OF LAKELAND. 13

the tributary crosses to the southern side of the drift-filled depression,
and east of this the rock lies on the southern, the drift on the northern
bank. At the top of the pass, the path is on the northern border of
the drift-filled depression, which is readily traceable towards the tarn.
Some way below the top of the pass on the Watendlath side, a stream
called Bowdergate Gill runs along the depression, and has cut a
ravine in it, which is well wooded towards the tarn. In some places
this ravine is about

50 feet deep, and is cut Fig. 1.

entirely through drift, w.
with drift forming the

bed of the stream.

It may be noted that ZY
on looking towards the gw
eastern side of Borrow- “ig
dale from below Ros-
thwaite, the col above-
mentioned is the only
place where solid rock is .
not visible against the Rea: Else
sky-line for a distance of about 2 miles, and it is also the lowest
portion of the sky-line in this space.

There are indications of an old terrace some way above the
present surface of the tarn, which are most clearly seen on the
eastern and southern sides. This probably marks the original
height of the old col between the former Watendlath and Lowdore
valleys, which would form the exit of the lake after the stoppage of
the narrow Watendlath-Rosthwaite gorge, the rocky ravine just below
the tarn having since been deepened to the extent indicated by the
difference of level between the present surface of the tarn and the
summit of the old terrace.

Stream
From Brund Fell
‘

;

et

(6) Hard Tarn, Helvellyn.

In his paper on ‘The Glaciation of the Southern Part: of the
Lake-District and the Glacial Origin of the Lake Basins of Cumber-
land and Westmoreland,’’ Clifton Ward remarks (p. 161) :—‘ Just
below and south of Nethermost Pike, Helvellyn, in Ruthwaite Cove,
is Hard Tarn, 150 feet by less than 100 in size; it is very shallow,
so that one can see the rocky nature of its bed and sides, and mark
how the ice-scratches pass beneath the water from one side to the
other.’ Owing to the above statement and to the small size of the
tarn, which might well be a rock-basin, even if the other tarns of
the district are only drift-dammed, I was particularly anxious to
see this lakelet, but was prevented by bad weather in former years.
This year I had an opportunity of examining it. The pond lies on
a dip-slope of some ash-beds having a gentle inclination towards a
steep escarpment-cliff above, which is surmounted by another dip-

? Quart, Journ. Geol. Soc. vol. xxxi. (1875) p. 152,

14 MR. J. E. MARR ON THE TARNS OF LAKELAND. [ Feb. 1896,
slope; this at one time evidently contained a lakelet similar to that

existing on the shelf below, though it is now almost entirely con-
verted into a peat-bog with a small pond in the middle (see fig. 2).

Fig. 2.—Section across Hard Tarn.

H.T.=Hard Tarn. | P=Pond.

B= Peat Bog. S =Screes.

Below the dip-slope of Hard Tarn is an escarpment; similar to that
seen above. The accompanying plan (fig. 3) shows the nature of

Fig. 3.—Plan of Hard Tarn. (Scale: 5 feet =1 mile.)

bare glaciated
rock below

, aN
HD

C Mie
x= Deepest point. d= Delta. E=Normal exit over screes.
CC= Cliffs. S=Swamp. W.E.=Wet-weather exit over
rock.

the tarn and its surroundings. The deepest part of the tarn at #
is only 3 feet, and the greater part of the northern side varies in

‘Vol. 52.] MR. J. E. MARR ON THE TARNS OF LAKELAND. 15

depth from 3 to 2 feet, the tarn gradually shallowing towards the
south. The normal exit is at the western end, by a stream running
through screes (#), and although these screes form so insignifi-
cant a feature in the landscape that they might readily be overlooked,
and the rest of the lake is surrounded by solid rock, actual measure-
ment revealed the fact that the shortest distance from rock to rock
‘near this exit was about 25 feet, so that there is little doubt that
this tarn owes its existence to the blocking of one end of a sloping
dip-slope between two escarpments by screes. A feature of particular
interest was noticeable at the time of my visit after heavy rains.
Another stream ran from the middle of the southern side of the tarn
from the abnormally high lake-level, over the lower escarpment,
along a shallow groove. As this groove must be gradually deepened
during wet periods, while the screes are increasing at the exit,
the time will arrive when this tarn ceases to be one having its
exit over loose material, and sends its surplus waters permanently
over the solid rock. We have here an intermediate stage in the
“process of formation of such tarns as Codale, described in my
former paper.

(c) Hayeswater.

I examined this large tarn lying below High Street, and south-
east of Patterdale, because, in the discussion upon my former paper,
it was cited by Dr. Mill as a possible connecting-link between the
tarns and the valley-lakes. It lies at an elevation of 1383 feet,
and the last rock seen in Hayeswater Beck, which issues from it, is
near the point where the 1250 feet contour-line crosses the beck.
The tarn might well be deeper than 133 feet, and still be drift-
dammed, for the hill on the left bank of the gill has a thick bank
of drift running far down Hayeswater Gill valley, and a buried
valley of great depth might well exist beneath this. In many
places, Hayeswater Beck seems to be cutting its way between rock
and drift, as described in the case of the stream from Brund Fell,
near Rosthwaite. Hayeswater therefore presents no indications of
lying in a rock-basin.

(dq) Angle Tarn, Patterdale.

This tarn lies on a plateau beneath Place Fell. It is evidently
- quite shallow, for numerous boulders project above its surface in
different parts, and it is hardly likely that anyone would claim it
as a rock-basin, with its numerous rocky bays, its two islands and
peninsula. It was formed by the stopping of a depression starting
from the northern end of the tarn, and running round the rocky
knoll north of the present exit, to join the beck proceeding from
this exit, a short distance west of the tarn.

16 MR. J. E. MARR ON THE TARNS OF LAKELAND. [Feb. 1896,

Discussion.

Dr. H. R. Mitt said that he was much interested in the Author’s
observations, especially those on Hayeswater. He wished that there
were facilities in the meeting-room for optically projecting photo-
graphs, as a photograph he had taken from the top of High Street
showed the glacial accumulations in the narrow valley very
distinctly. As Mr. Marr had found every tarn that he examined
to be held in by a barrier of drift, it seemed very likely that most,
if not all, of the larger lakes would be found to owe their origin to
the same cause. In this connexion it was worth mentioning that
Prof. W. M. Davis, of Harvard, considered, from the configuration
of the larger lake-basins in the district, that they were produced in
drift-blocked valleys.

The AvutHor thanked Dr. Mill for his remarks. He observed
that even if Hayeswater were abnormally deep for mountain-tarns,
there was sufficient drift to block it. He had already written
a paper on the origin of the larger lakes of Lakeland, and submitted
it to another Scciety.

Vol. 52.] THE ROCKS OF THE LIZARD DISTRICT, 17

3. The SERPENTINE, GNEISSOID, and HornBLENDE Rocks of the Lizarp
Disraict. By T. G. Bonnzy, D.Sc., LL.D., F.RS., F.GS.,
Professor of Geology in University College, London, and Fellow
of St. John’s College, Cambridge. (Read November 6th,

1895.)
[Puate I.]
ConTENTS. Page
BPPMIMOGICLOEY, Ff copacanonnsansocs aqrerencedasasennisine<brapie ainhivcidbih nlndaage since ar 17
TI. The Genesis of the Hornblende-schists ...............ssceeccecceccen ceescees 18
(a) Inclusions in the Hornblende-schist at Porthoustock Cove ...... 19
(6) Inclusions in the Hornblende-schist south of Kilcobben Cove... 20
(c) Quarry on the descent to Mullion Cove ..............ssseceeeeeseeees 20
Til. The Genesis of the ‘ Granulitic Group ’.........ccc..cececesececcseceeocsneces 22
IV. Relations of the Serpentine to (a) the ‘Granulitic Group,’ (0) the
PRWORE TECHS “SR IITSER ots cie een ape once wca cece mn cicnnin Uneise ven cin np eelte Aaleanates
NIC SaT EU SaGSOGSTES/ 0). PD oe ee as os eae ae cae Dac als cen eds deal adeesacesPlenedecine 40
MMMM RR RETAIS ps a8 n 2: Wogan ehioac- arn tnarnmansiessoceucnndmaeamiaht’ scdesbencenten 42
(a), Miscellaneous Notes... -c.2.21 is; .aasacneniescmncdaadeddcnde-acecareaneemes 42
(pee on Maer bizar’ HoCks fea .cn-tenadennanchndera-esensrep-edeperscGeniaee 47

I. IntrRopuctToRY.

Ty 1891 a communication on the rocks of the Lizard from General
M°Mahon and myself was honoured with a place in the Society’s
Journal.! As therein stated, we were of opinion, at the time of our
visit to Cornwall (August, 1890), that to regard the banded members
of ‘the hornblendic group’ as stratified basic tuffs, subsequently
metamorphosed, was ‘ the better working hypothesis.’* But, even in
that interval, as will be seen by a note appended to the paper,’ some
doubts as to the correctness of this conclusion had already arisen
in my mind, for a visit to Sark in the spring of 1891 had suggested
explanations of certain difficulties which hitherto had seemed in-
superable in an alternative hypothesis. Accordingly I became
anxious to see how the old puzzles looked in the new light, and
besides this a very important paper by my friends Messrs. Howard
Fox and J. J. H. Teall,* subsequently published in this Journal,
made it a necessity for me to study the sections of which they had
given so lucid a description. For, if their interpretation of these
were correct, the geology of the crystalline rocks of the Lizard
peninsula would be thrown (as it seemed to me) into hopeless con-
fusion. The authors, indeed, restricted their conclusions to the
sections which they had described ; but it appeared to me, for reasons
which will be given hereafter, that no such limitation was possible,
and that if they were right I must have misinterpreted the evidence
in other localities. I felt, indeed, so much confidence in the general

1 Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 464.

2 Op. cit. p. 480. 3 Op. cit. p. 479.

* Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 199.
Q.J.G.8. No. 205. c

18 PROF. T. G. BONNEY ON THE [Feb. 1896

accuracy of my observations that under ordinary circumstances I
should have deemed it needless to revisit the district; but when
two such critics, the one so keen an observer, the other so skilled a
petrologist, both entered the lists against me, though in the most

friendly contest, I felt compelled to take the first opportunity of

revising my work. This was done in the summer of 1894. Other
engagements unfortunately prevented Gen. M°Mahon from giving
me the pleasure and the benefit of his company, but I had the great.
advantage of the society and co-operation of the Rev. E. Hill, with
whom I have so often worked in this and other regions, and to whom
I tender my best thanks for constant aid. [He has kindly read a.
proof of this paper, and requests me to say (as I do most gladly):
that he can confirm all the statements as to what was seen in the
field. ]

Going first to St. Keverne, we succeeded, as we hope, in clearing up
a minor difficulty, which our former visit had failed to solve, and
we reviewed the hornblende-schists of this neighbourhood. Then,
in a fortnight’s hard work, from Lizard Town as a centre, we care-
fully studied all the sections, as far as Mullion Cove on the west
and Kennack Cove on the east, which seemed likely to throw light
on the problems specially before us: namely, the genesis of the
hornblende-schists and of the so-called ‘granulitic group,’ and the
relations of these rocks to the serpentine and to certain other rocks
of igneous origin, but less altered than it. The former problem
need not be discussed at any great length, though we accumulated
a large number of observations, bearing upon it. The latter one im
reality involves the whole question of the relations of the crystalline
rocks in the Lizard district, and so demands a rather full treatment.

Il. Tue Genesis oF THE HoRNBLENDE-SCHISTS.

It will suffice to refer to former papers for descriptions of the
petrography of this interesting group. As to the facts, I believe that
Messrs. Fox and Teall, Gen. M°Mahon, and myself are practically
in accord.’ From the neighbourhood of the lighthouses near Lizard
Town to Pollurian Cove on the west (a distance in a straight line
of about 5 miles) and to Porthallow Cove? on the east (93 miles),
this group, whenever it appears, exhibits substantially the same
characteristics. It varies from a dark rock, more or less speckled
with white, sometimes so little foliated as to be barely distinguishable
from a diorite, occasionally even retaining slight indications of an
ophitic or of a porphyritic structure, to one which is clearly foliated
and sometimes well banded: dark hornblendic layers alternating
with those of a whitish or of a yellow-green colour, the former
being rich in felspar, the latter in epidote. The more banded

varieties occasionally exhibit a structure which curiously resembles:

1 Quart. Journ. Geol. Soc. vol. xxxix. (1883) p.1, vol. xliv. (1888) p. 309,
vol. xlv. (1889) p. 519, vol. xlvii. (1891) p. 464.

2 [adopt the spelling of the 6-inch Ordnance map ; formerly it was Porthalla,
as in previous papers. Ai

4

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 19

false or current-bedding.’ This, as stated in our paper of 1891,
was difficult to explain on any other hypothesis than that of an
original stratification, which also accorded very well with the aspect
of the banded rock. Doubts, however, as mentioned in the paper
on Sark by Mr. Hill and myself,’ had arisen as to the validity of these
difficulties, and proof had been obtained that distinct mineral
banding might occur in a true igneous rock of like composition,’
so that the whole question was investigated de novo. Three locali-
ties appeared to supply evidence of special importance, which I shall
endeavour to describe.

(a) Inclusions in the Hornblende-schist at Porthoustock
Cove.

The hornblende-schist on the northern side of this cove is some-
times very dark in colour, sometimes rather conspicuously streaked
or banded with felspar: the more homogeneous and the more banded
rock alternating twice or thrice, in a vertical space of about as
many yards. Sometimes fairly well-formed crystals of white felspar
occur porphyritically in the dark rock, up to about 3 inch long,
sometimes the rock becomes coarser and recalls the structure of a
hornblendic gabbro. Now and then‘ the latter rock forms a kind
of ‘eye’ in the normal banded schists and presents a structure
resembling current-bedding (fig.1). But rather towards the western

Fig. 1.—One of four ‘eyes, consisting of a coarse, gabbro-like
material in the normal hornblende-schist. (North of Porthoustock
Cove.)

Case 202 hy Bo Et —
fe wae Seok eee eee aSSi ry — =. =o = et

a

————

a Let
= mS ~~
= i= SIS? SNS SLES
ne ee San ae
Rana S20 i a
Ss es —— a re = = ry
a-

y i =
=> ss SS SSS es a ae

end of the Cove we found an inclusion of nearly pure, rather
coarsely crystallized hornblende. It is about 6 or 7 inches thick in
the part drawn (fig. 2, p. 20): the ordinary hornblende-schist
bending round it, as-indicated, but it ‘trails out’ to the right and,
interruptedly (there are two layers), to the left. In this direction, at
about the same level, are two or three similar but smaller inclusions.
A slice from the largest inclusion ’ shows it to consist almost entirely

1 Quart. Journ. Geol. Soc. vol. xxxix. (1883) p. 4; see pl. i. fig. 2.
- ® Ibid. vol. xlviii. (1892) p. 122. ;

3 Op. cit. pp. 184-138, af. p. 124.
* 4 T saw about four instances —varieties of linear streaking were countless.

° The specific gravity of the specimen, as determined with a Walker’s balance,
is 3°124 ; the mean of two specimens of fairly normal hornblende-schist is 2°748.
I am indebted to Miss Raisin for these and other determinations in this paper.
T ensure accuracy, each of us read the balance.

c2

20 PROF. T. G. BONNEY ON THE [Feb. 1896,

of a dull green, rather strongly pleochroic hornblende, in somewhat
irregularly-formed crystals, commonly much speckled with minute
and elongated specks of iron oxide. Some larger granules of the
latter mineral occur, with a little rutile and possibly pseudobrookite.
Besides, there are a few isolated grains or granular patches of a clear

Fig. 2.—Eye of hornblendite, included in banded hornblende-schist.
(Northern side of Porthoustock Cove.)

LAY Rey
ap ess one (hy 2%
Gi
WA nia

a = banded hornblende-schist.
b = coarsely crystallized hornblende.

mineral : this has rather a high refractive index and low polarization-
tints for a felspar, an extinction, I think, oblique (it is difficult to get
any line from which to measure), and it may perhaps be a colourless
epidote. These inclusions, though on a much smaller scale, recall
to mind those which we found so common in Sark.*

(6) Inclusions in the Hornblende-schist south of Kilcobben
Cove.

Here also the rock is frequently streaked, and instances of
resemblances to current-bedding are by no meansrare. Near to the
northern side of the promontory we found long lenticular masses of
rather coarse hornblendic rock, such as is described above, lying with
their flat sides roughly parallel with the dominant banded structure,
They are seldom more than 2 or 3 inches thick, but are sometimes
2 or 3 feet long and almost as wide.’ From this size they may be
found down to little patches, almost streaks.

(c) Quarry on the descent to Mullion Cove.

This quarry, noticed in the paper of 1891,* was in a better con-
dition for study at the time of our visit in 1894. The rock here is
generally coarser in structure than any other mass known to us in
the Lizard peninsula. Most of it shows a banded structure, which,

1 Quart. Journ. Geol. Soe. vol. xlviii. (1892), p. 128, ete.; see also vol. xliii,
(1887) p. 324.

2 In aslice from one of these I find nothing but hornblende, like that described
above, and a little iron oxide.. But the rock was very difficult to cut, and the
slice is a rather thick one, > Op. jam cit. p. 479.

Vol. 5 Be ROCKS OF THE LIZARD DISTRICT.. 21

however, here and there disappears, for it passes into a ‘spotty’ one.
But the general condition of comparatively coarse crystallization is
replaced, locally and rapidly, by a finer one; the latter exactly
resembling the normal hornblende-schist, whether banded or
‘ dioritic,’ which occurs elsewhere at the Lizard. Fine-banded and
coarse-banded portions may be seen, one within a foot of the other.
Of the latter variety, bands, quite ; inch thick, consisting almost
wholly of felspar, can be traced frequently for more than a foot in
length ; bands also, both light and dark, sometimes quite 4 inch thick
and occasionally more, run continuously for 8 or 9 inches at least.
One part of the rock presented a curious resemblance to false bedding,
but a closer examination showed that this might be equally well
produced by a shearing movement in the mass. In another place
the bands were overfolded, and appeared to have become displaced by
a ‘strain-slip’ movement. The latter, no doubt, might be produced
after the solidification of the rock, but the general appearance of
the former structure and the absence of divisional planes suggested.
that it was due to a sliding movement, while the mass was still more
or less viscid, so that the ruptured surfaces had become cemented
during the last stage of crystallization. The irregular and sporadic
passage from the banded to the spotty condition also seemed difficult:
to explain if the former were due to an original stratification of
clastic materials, but seemed easily explicable on the hyp6thesis that
movements had taken place in a magma, after some constituents
had separated, but anterior to the complete crystallization of the mass;
this had caused the ordinary ‘ granitic’ structure of a holocrystalline
rock to be replaced in many parts by a banded one.

It has, however, been suggested that these linear structures are
due to a yielding—more or less local—in a coarse holocrystalline
rock when subjected to pressure. Apart from considerations which
I have elsewhere noticed,’ I had this hypothesis always before my
mind and found it inapplicable as a general explanation, though I
should admit the possibility of its accounting for a certain ‘slabbi-
ness’ occasionally perceptible.2 The effects of dynamo-metamorphic
processes, in the ordinary sense of that long word, can be studied
at the extreme south and in a more limited area at Porthallow,
as described in our former paper, and the conclusions then formed
were strengthened on the present occasion by tracing, especially in
the first-named district, the gradual change from the normal horn-
blende-schist to the pressure-modified ‘green schist.’ If then the
ordinary banded hornblende-schist of the Lizard owes its structure to
‘dynamo-metamorphism,’ recrystallization must have subsequently
occurred to such an extent as to destroy every characteristic of that
process. ‘T’o concede this, I may observe by the way, would be fatal
to every attempt to implicate the schist and the serpentine in an
‘igneous complex,’ for the latter rock, as a rule, exhibits no sign of

1 Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 94, and vol. 1. (1894) p. 279.

? But, even if this be due to a very slight shearing, its parallelism with the
banded structure and consequent low hade (universal features, so far as I know)
are by no means easy to explain.

22 _ PROF, T. G. BONNEY ON THE [Feb. 1896,

crushing or of recomposition, whether as serpentine or as peridotite.
The breadth and persistency of the bands in this hornblende-schist,
as I have more than once pointed out in similar cases, are further
difficulties in the dynamo-metamorphic hypothesis. In order to
obtain by crushing bands such as those described above, the original
rock would have had to be almost incredibly coarse ; yet such bands
are not infrequent both at the Lizard and in Sark.

As regards the ‘stratification’ hypothesis which I formerly ac-
cepted, I may mention a difficulty, the gravity of which has increased
with my experience. If the rock originally were a basic tuff
(and no other materials would give us the appropriate chemical com-
position), the conditions of deposit must have been very exceptional.
Undoubtedly, beds of fine-grained ash occasionally exhibit great
regularity of structure, but commonly this is speedily interrupted
by the setting in of coarse material, the rock becoming ‘ knubbly’
if not agglomeratic. But these hornblende-schists are singularly
free from blotching or irregular spotting’; the bands of different
mineral composition alternate just as the arenaceous and argillaceous
layers at Morlaix in Britanny or Port Erin in the Isle of Man.
This difficulty might, indeed, be eluded by supposing the materials
to have undergone metamorphism so extreme as to dissociate the
constituents of the bits of tachylyte and the lumps of scoria,
and that to have been followed by an orderly process of segre-
gation somewhat analogous to what occurs in the formation of
flint, converting ultimately the rather heterogeneous materials into
fairly uniform mixtures of minerals not at all minute. This
hypothesis, however, though obviously a possible one, obliges us,
as I feel more and more strongly, to assume conditions which are so
exceptional that they can hardly have prevailed over such large areas.
Hence I am forced to adopt the other hypothesis.”

III. Tas Genesis of tHE ‘ Granuxitic Grove.’

On this subject fewer words are needed. I may content myself
with saying that the result of this visit has been to strengthen my
confidence in the correctness of the explanation adopted in our last
paper,® namely, that these banded rocks have been produced, as
probably most banded gneisses have been produced, by fluxional
movements in a heterogeneous magma; the cause of heterogeneity
in this case being, as in the one described in Sark,* the intrusion
of an acid into a more basic rock, by which the latter has been

1 The nearest approach to this is the case near Mullion Cove, described above,
and even here there is nothing resembling the irregularity which is usual in
volcanic ashes.

* It also accords better with that which is now generally adopted for the
granulitic group. This is supposed to be almost in the condition which it
assumed on consolidation ; but its darker member is sometimes not very
different from corresponding parts of the hornblende-schist, so that one can
hardly assume the two rocks to have had totally diverse origins.

3 Op. cit, vol. xlvii. (1891) p. 477. 4 Op. cit. vol. xlviii. (1892) p. 132.

Vol. 52. | : ROCKS OF THE LIZARD DISTRICT. 23.

softened, drawn out, and even locally melted down and absorbed
by the former. One section, which I found on the southern side
of Kennack Cove, so well illustrates this process that it deserves,
perhaps, a brief description. A light-greyish granite is intrusive into
.a dark dioritie rock, which it has shattered into a breccia, but in
places one can see that the latter is locally melted by and incorporated
‘with the former, the result being a regular, rather fine-grained,
streaked or banded gneiss. I obtained specimens of all three rocks
and have examined them under the microscope. The granite consists
mainly of quartz and felspar, with a rather small amount of biotite
(somewhat bleached)? The structure is granular, only one or two
of the larger felspars showing any approach to a crystal-outline,
and the grains differ much in size. It exhibits the association of
‘this mineral and the quartz to which I have often called attention
as more characteristic of a gneiss than a normal granite,’ with a
‘very slight approach to a linear order in the constituents, The
dioritic rock consists of felspar, rather decomposed, apparently
plagioclastic, green hornblende, biotite (not much, and rather
sporadic), with a little sphene, etc. The structure is granular,
-with occasionally an approach to ophitic, and felspars, 4 or 5 times
the diameter of the rest, occur sparsely. The banded gneiss has a
general resemblance in structure to the granite, except that its
felspars are even more variable in form and size, the linear ordering
of the constituents is more marked, and grains with micropegmatitic
structure, which are rare in the other rock, are common here;
apatite is more conspicuous and two or three very small garnets
occur; there is a considerable amount of a rich brown biotite, but
hornblende is absent; at least I do not find a single scrap (there
are a few green flakes) that I can identify with certainty. On the
significance of this I have already written.*

Additional evidence, however, was obtained in regard to one
point of interest. I have always believed the granulitic group to
overlie the hornblendic, though I felt that the evidence in favour of
this was not very strong. The latter rock usually occurs in great
continuous masses, the former in more or less interrupted blocks,
which, though they may be sometimes traced with but little inter-
ruption for considerable distances, are associated (always so far as I
remember) with the serpentine, and occur in such a manner as to
give the impression that they are fragments of a mass which it has
shattered, and in some cases actually transported. In one place,
however, in the crags on the south side of Cadgwith Cove, as men-
tioned in our former paper,’ the granulitic rock appeared to be
superposed on the hornblendic schist. On the last occasion, favoured

1 The specific gravity of the granitic rock is 2°611, of the dioritic 2:917, of
the banded gneiss 2°628: intermediate, but,as we might expect from its appear-
ance, nearer to the first.

2 In these descriptions and throughout the paper, minor details of composition
and structure are suppressed, as being without significance for my main purpose,

8 Quart. Journ. Geol. Soc. vol. xxxvi. (1880) p. 97, ete.

4 Ibid. vol. xlviii. (1892) p. 132,

5 Ibid. vol. xlvii. (1891) p. 478.

94 PROF. T. G. BONNEY ON THE [Heb. 1896,

by a calm day, we closely examined, from a boat, the whole line of
cliffs from Church Cove to Cadgwith. We found that, after passing

the huge mass of hornblende-schist which forms the crags of Carn-

barrow and the gloomy portal of Dolor Hugo, the rock, on approaching
the archway leading into the ‘Frying Pan,’ continues, for some
distance above the sea-level, to-be a true hornblende-schist, but that:
there are, in the upper part of the cliff, several reddish granitic veins,
the direction of which appears to have a rough correspondence with
the structure of the former rock, while the cliff above these assumes
amore ‘granulitic’ aspect. On the southern side of the entrance
to the ‘ Frying Pan,’ a fault, or group of faults, brings serpentine
and typical ‘ granulite’ against hornblende-schist. But, immediately
beyond the archway, the headland between it and Cadgwith Cove
presents the following section. The upper part of the cliff, beyond.
all question, consists of the granulitic rock; while the lower part,
at the south-eastern corner, for a considerable height above the sea,
is no less typical hornblende-schist. The two rocks gently descend
in a northerly direction until, near the north-eastern angle, the
hornblende-schist gradually disappears beneath the water and the
mainland crags consist wholly of typical banded granulite; though
even here the hornblende-schist still appears in some skerries very
near to the shore. Passing round into the cove, we find that its
southern side, as we formerly stated, consists mainly of the ‘ granulitic
group, but that near the water’s edge the rock generally is a horn—
blende-schist.!_ No sharp line can be drawn between the two groups,
but between the well-banded and thoroughly typical representatives:
of each there is usually a zone from 7 to 10 yards in thickness,
rather neutral in character: veins of a reddish granitic rock,
breaking, on the whole in a horizontal direction, through a dark
rock which now and then resembles the basic member of the granu-
litic group more closely than the dark part of the hornblende-schist..
Obviously, if both these groups are igneous in origin, this super-
position cannot count for much. It may, however, have the signi-
ficance, that, on the assumption of the hornblendic rock being the
earlier extrusion, the upper part of its mass would offer less resist--
ance under ordinary circumstances to the passage of an intruder.
Hence the phenomenon may have a bathymetric significance, if it.
has no other. ,

LY. Renarions oF THE SERPENTINE TO THE ‘GRANULITE’ AND TO
THE HoRNBLENDE-SCHISTS.

Before discussing the group of sections near Ogo-dour and east:
of the Lion Rock, from which my friends have drawn certain con-
clusions,’ I must make a few remarks upon the general principle,
which, as it appears to me, is implied, if not actually enunciated in

1 Tt is regularly banded, the white felspar and dark hornblende showing 2
hypophitic structure, and differs only from the most normal hornblende-schists:
in becoming here and there slightly micaceous. x

2 Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 210.

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 25

their paper.1 It amounts to this: that in an extensive district,
where the rocks exhibit many difficulties and complications, each
section or limited group of sections can be regarded by itself and be
made the basis of induction, independently of all the others. But
here, unless I mistake, lurks a fallacy, the nature of which will be
readily perceived by considering a particular instance as an illustra-
tion. Suppose the question to be whether an igneous rock is intrusive
into or contemporaneous with a group of sedimentaries. Suppose,
further, that in 11 out of 12 sections the evidence is inconclusive, but
that the remaining one gives a decisive answer on the one side or the
other. Then there would be no room for furtherdoubt. The uncertain-
ties of the eleven would count for nothing against the positive evidence
of the one section. Suppose, however, that, of the 12 sections, the
evidence of four or five is rather more favourable to one conclusion ;
that of two makes any other highly improbable, while that of one
appears to accord better with the contrary conclusion; and the
remainder give no answer at all. We cannot regard the testimony
of this one unfavourable witness, as if the others were non-existent.
Certainly no judge, probably no jury, would act upon such a principle.
The apparent conflict of evidence undoubtedly calls for a careful
cross-examination of each witness, but in such a case as we have
mentioned it is surely far more probable that the one section
should have been misunderstood than that a contradiction should
exist. The more specious interpretation does not always turn out
to be the true one, and we must proceed in our attempts to learn
the secrets of Nature as men who are seeking to decipher inscriptions,
where the language is dead and the characters are obsolete.

It may be said, however, that the ordinary laws of inductive
reasoning do not apply to this particular case, because we are
dealing with an ‘igneous complex.’ The term undoubtedly is an
attractive one; there is a certain mystery about it, but there is also,
as in all mysteries, a certain vagueness. ‘Complex’ means a tangle,
and thus is a term which fails to explain anything ; to fall back upon
it, is a confession of defeat and an admission that when Nature
plays the Sphinx we decline to take the part of Cidipus. In the
case before us, however, the authors’ meaning may be inferred from
_ certain conclusions which they have formulated.? These, briefly stated,
amount to this: that in the cliff and on the adjoining shore, east of
the Lion Rock, the serpentine is traversed by basic dykes, which pass
locally into hornblende-schist, and besides this put on, in the thicker
portions, appearances which are characteristic of the ‘ granulitic
group’; also that there is a wedge-shaped mass of this granulitic
rock, which exhibits a structure incompatible with the hypothesis
that the serpentine was intruded after the mass itself became
solid.

In regard to these conclusions, I may venture at the outset to
make the old comment Dolus latet in generalibus. (a) ‘The dykes
pass locally into hornblende-schist.? Yes, but into what horn-

Op. cit. p. 200. 2 Ibid. p. 210.

26 PROF, T. G. BONNEY ON THE [ Feb. 1896,

blende-schist ? Is it the same as the rock which forms the great
cliffs of Carnbarrow and Hot Point, of Housel Bay, and Predannack
Head, not to mention other places? By no means, I should say.
True, the dominant minerals are the same in both, and these dykes
exhibit locally a trace of foliation. That is also true of other dykes
in this region’; nevertheless, the hornblende-schist proper, as a rule,
is a very different rock, even macroscopically. It iscommonly more
or less banded, almost always distinctly ‘linear’ in structure; only
rarely and only very locally would there be any difficulty in dis-
tinguishing the one from the other. I find that the same holds good
ef the microscopic structure of the two rocks; the differences can
hardly be expressed in words, but asa rule they exist. What, then,
does this prove? That sometimes, if we take two hand-specimens,
carefully selected from two groups of rocks, differing in age and
history, we may be unable to distinguish the one from the other,
because neither presents characters upon which we can fasten for
that purpose. We might as well affirm that the Greek and the Latin
uncial alphabets belong to the same language because certain letters in
the two are identical. Has any one of these dark pyroxenic dykes
in the Lizard region exhibited such a banded structure as that which
occurs again and again in the ‘hornblendic’ group? It would be,
in my opinion, just as reasonable to contend that the hornblende-
schist was only a modification of the gabbro,* because now and
again, though very locally, resemblances can be detected; or that
all the basalt dykes of Scotland were of one age, because it is not
always easy to say whether a particular one belongs to the Paleozoic
or to the Tertiary era. (6) ‘The dykes near the Lion Rock, in
their thicker parts, sometimes resemble the granulitic group.’ To
this we may reply in terms similar to those already used. Once or
twice a dyke may be found to exhibit some rather irregular fel-
spathic veins or seams. But this, so far as my experience goes, is
not a very uncommon feature in districts such as the Lizard. The
resemblance between the two rock-masses seems to me hardly closer
than the notorious one between Monmouth and Macedon. I have
found it difficult in other places to distinguish between veins of
infiltration and of intrusion, yet this does not prevent me from
believing that each really exists, and can be often identified. So
that im this case also, while I grant that certain resemblances may
be found, I deny that they are sufficient to warrant the conclusions
which have been drawn from them.

(a) Relations of the Serpentine to the Granulitic Rock.

But I pass from generalities to particulars, and first to ‘the
wedge-shaped mass of typical granulitic rock.’ There can be no
question that this—like the great masses which crop up on the

~ 1 Quart. Journ. Geol. Soc. vol. xxxix. (1883) p. 6 (reference).
2 Tf so, there should be no ‘complex,’ for the gabbro cuts the serpentine
again and again. .

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 27

shore some little distance to the south, belongs to the granulitic
group. The drawing which my friends have given is substantially
accurate!; the inference also which they draw is correct, but only
in an extremely limited sense—in other words, everything turns
upon the exact meaning at- ith

tached to the phrase ‘solid Fig. 3.—Projection from the

egranulitic rock.’ Taking that granulitic mass included wm
mass as a whole, its darker serpentine. (Hast of the Lion
bands indicate firstly, the for- Rock.)

mation of a banded or rather a
streaky structure, and secondly
the contortion of the same’;
but, so far as I could see, no
connexion exists between these
structures as a whole and the
external shape of the mass, and
there is nothing to difference
this block from those which
occur, as I have said, to the

In all these diagrams the serpentine is
ae one a ‘aa oe dotted, and the fine lines indicate the
os pine ee Me more micaceous bands in the granu-

only rather curiously con- litie rock.

torted, but this structure is not

very uncommon in the granulitic group, and I was unable to see
that any relation existed between either it or the shape of the
mass and the serpentine, or to find evidence either that the granu-
litic rock was intrusive in the serpentine or that the two had been
folded together, as the result of earth-movements while both were in
a plastic condition. As is stated above, there are two large masses
of the granulitic rock on the shore towards the south. These, how-
ever, are not wedge-shaped intrusions, but huge blocks; yet in places
they exhibit contortions, which are hardly less pronounced than
those in the other mass.* ‘The serpentine in their neighbourhood
exhibits a slight foliation, which dips at a high angle to a point a
little W. of W.N.W., but this neither makes the rock fissile, nor
produces any marked effect on its microscopic structure, nor stands
in any relation to that of the granulitic masses. :

I accordingly claim a verdict of ‘ not. proven’ here, and pass on
to other localities to see how far their evidence is ‘incompatible
with the theory that the serpentine was intruded into solid granu-
litic rock.’ At the first glance it seems possible to explain the

1 Op. cit. p. 209, fig.4. I venture to suggest two trifling emendations. At B
the obtuse angle should be replaced by a blunt thumb-like projection (see fig. 3,
above), and at D the serpentine occupies the wider, but not the narrower part of
the inlet in the granulitic mass: the latter rock being practicaily continuous at a
depth of 3 or 4 inches, as I could see in one place and feel with my fingers all
along. ‘To this point I shall return.

* These might be either successive stages in one process or separated by
some considerable interval of time (as I incline to think).

In these, however, the ‘dioritic’ rock predominates, so that it is granitic
(lighter-coloured) bands that wriggle about.

28 PROF. T. G. BONNEY ON THE [Feb. 1896,

relation of these two rocks by one of four hypotheses: (a) that the
two rocks have been brought together by faults; (6) that the two
have been folded together ; (c) that the two have flowed together ;
(d) that the serpentine is intrusive in the granulitic rock.’

As the relations of the two rocks have been described in former
papers, I shall not repeat what is already in print, but content
myself with remarking that though I have again examined all these
cases, I find no reason for altering my statements, and with describing
very briefly a few other instances. As a preliminary, 1 venture
to remind the reader that the granulitic rock commonly occurs as
blocks, which sometimes appear to be completely included in the
serpentine, but at others may be either projecting ridges or crags
attached to much larger masses below or behind the visible surface.
Where these exhibit a definite structure, this seems more or less to
determine their outline, so that well-banded varieties are often fairly
rectangular in shape; but as such a structure is not always present,
considerable variety of form is possible. Though small slips and
displacements are common in the serpentine, the faces of these
blocks do not appear, as a rule, to correspond with faults ; moreover,
the two rocks occasionally, though not commonly, are welded
together—in other words, the relations of the granulitic rock and
the serpentine appear to me, as a rule, incompatible with the first
or the second hypothesis. As for the third, it may be understood to
mean either that the two rocks have been simultaneously emitted as
parts of a magma already separated in accordance with Soret’s or
some other principle, or that the one material has been injected into
the other, and has so completely softened it, if it were already
solid, that the two have subsequently flowed on together. Now,
the granulitic mass itself exhibits irregularities in structure and
variations between the extremes of mineral composition, which
accord well enough with the one or the other of these interpreta-
tions; but between it and the serpentine no transitional condition
can be found, neither does it occur in lenticular or streak-like bands,
such as the third hypothesis would lead us to expect, but in blocks ;
while the fourth hypothesis, as I trust will be perceived from the
evidence which I am about to quote, accords better with the facts.

Time, however, may be saved by noticing at the outset a general
objection which might not unreasonably be raised, namely that, if the
serpentine be intrusive in the granulite, its relations to the latter
are rather unusual. It has formed neither dykes nor branching
veins in the ‘ granulite,’ nor has it shattered that rock and caught
up numerous small fragments. Yet all these are done by granite,
diorite, gabbro, and other deep-seated rocks, as well as by their
more compact representatives. The serpentine adopts the form,
as those holocrystalline rocks often do, of irregularly-rounded
bosses or somewhat elongated tongues, but it is not connected, as
they very commonly are, with peripheral dykes and veins. This,
however, appears to be the usual habit of peridotites and serpentines.

* T exclude that already mentioned, namely, that the granulite is the intruder,

because, in the cases which I am about to mention, I cannot conceive the possi~
bility of its being seriously entertained

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 29

I have probably examined in the field more of these rocks—espe-
cially the latter—than most geologists, yet I have never seen a
branching vein, and only two or three dykes." The mode in which
this rock occurs generally suggests that it was extruded in a rather
‘ pasty’ condition ; sometimes also that the temperature was not
very high.”

But though the serpentine does not send veins into the ‘ granu-
lite,” its relations to that rock appear to me generally to suggest
and sometimes to prove intrusion. Take, for example, this instance
from Polbarrow Cove (fig. 4), where a fragment of serpentine about
14 inches long, 3 to 5inches

wide, and seemingly about Fig. 4,— Serpentine adhering to a

3 inches thick, still adheres ‘ step’ of granulite, in Polbarrow
to the granulite, which is Cove.

particularly evenly-bedded
(reddish grey with dark-
coloured) for about half a
yard above and a yard
below. Some two or three
yards behind the top of
the craglet is another and
longer mass of serpentine
which appears to occur in
asimilar fashion. Or this
case from the same cove (fig. 5), where the junction-surface is ir-
regular, the granulite for a short distance is disturbed, and two or
three small fragments

of it occur in the ser- Fig. 5.—Banded granulite (with fragments
pentine. Or this one in serpentine), south of Poltesco Cove.
from Enys Head,
where the serpentine
seems to have forced
open the granulite
along the lines of
banding, rumpling
those in its imme-
diate neighbourhood
(fig. 6, p. 30). Orthis
other one from the
same locality, where
the junction-surface is
puckered and squeezed up, while in one case (as shown in fig. 7,
p- 30) the bands of the granulite are cut off by the serpentine.
We found another, and a very marked instance of the same kind,

1 T do not forget the case in Forfarshire described by Sir Charles Lyell, but
I have not been in that part of Scotland.

2 I may add that in districts where the rocks have undergone much mechani-
cal disturbance, the junctions, as a rule, are spoiled. Serpentine is a brittle
rock, and commonly ‘yields to strains before its neighbours, so that a line of
junction is generally a line of fracture, and often of complete ‘smash.’ This
rule is almost universal in the Alps.

30 PROF. T. G. BONNEY ON THE [Feb. 1896,

near the White Rock, a little above sea-level, and the projection with
bent bands (fig. 8)

occurred, like those Fig, 6.—Serpentine and banded granulite,

above, in Polbarrow Enys Head.

Cove. I have, in-
deed, sketches and
notes of not a few
Similar cases in my
journal, but forbear
to multiply like figures
and statements. I
must, however, once
more refer* to the
remarkable mass in
the quarry at Kildown
Point, which again
has been most care-
fully studied. Before the excavation was made, it must have been
wholly or almost wholly enclosed in the serpentine. That rock
still rests in places on the top; ,
it forms one or two small tongues Fig. 7.—Serpentine and banded
between the bands of granulite, granulite, Enys Head.
and a blunt lobe at the base of
the southern side, where some of
these bands are bent and inter-
cepted. Yet in the immediate
neighbourhood of this mass the
serpentine does not show the
slightest sign of crushing ; it is in
a perfectly normal condition, while

that in the lobe, though rotten,
exhibits a slightly streaked or foliated structure, which, however,

makes a high angle with the horizon, though the bands in the granu-
lite are inclined at a low angle to

the same. But this is not all Fig, 8.—Serpentine and banded
the evidence. Masses of granu- granulite, Polbarrow Cove.
lite appear to crop out from the
serpentine on the almost pre-
cipitous slope below the quarry.
The descent of this would be so
hazardous that I have never made
the attempt; but this year I
managed to land from a boat in
a little cove at the base of the
cliff. Here we find granulite

1 Compare also the projecting mass of granulite in the included mass east of
the Lion Rock (fig. 3, p. 27), and note the outlines of the granulitic part and of

the micaceous bands.
2 Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 469; see also vol. xxxiii.

(1877) p. 899.

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 31

forming the southern, and serpentine the northern side of the
cove, and in the middle part a mass of granulite through which in
more than one place serpentine ‘ breaks irregularly, exactly as it
would break through a rather hard sedimentary rock, in places
forcing back and crumpling up some of the bands.’* One mass of
serpentine, of which I made rough sketches, was about 4 yards long
and2wide. That also showeda slight foliation or fluxional structure,
and this too was nearly at right angles to the bands in the granulite.
All the way up the crags above this place we see outcrops both of
the one rock and of the other.

I submit then, that these instances (and it would be easy te go on
multiplying them) show that the serpentine is really intrusive in
the ‘granulite.’ The former rock, however, must have been at this
time only in a semi-fluid condition—viscid and tough—so that it
was not able to do more than force its way occasionally along planes
of weakness in the ‘ granulite’ (blocks of which it often included
and perhaps tore away), softening the latter rock locally and
squeezing -it about, though the effect which it produced generally
extended only for a few inches away from the actual junction-
surface.

(b) Relations of the Serpentine to the Hornblende-schists.

The best sections for studying these relations, so far as I know,
are at ‘ Potstone Point,’ on the cliffs north of Ogo-dour, and at Hen-
scath, on the west coast; at Carnbarrow and in Porthallow Cove on
the east. Except the first, these were well known to me, and of it
I had a general knowledge. All, however, have been carefully
examined. First, with regard to the Potstone Point sections, of
which Messrs. Fox and Teall have given so admirable an account.”
These lead, in their opinion, to sundry conclusions, of which I quote
three,® as the rest need no further discussion :—

‘(1) The hornblende-schist and serpentine of the Ogo-dour district
form together a banded complex of crystalline foliated rocks.

‘(2) The relative ages of hornblende-schist and serpentine cannot.
be satisfactorily determined, but the occurrence of lenticles of
serpentine in hornblende-schist points to the conclusion that, if
there be any difference in age, the serpentine is the earlier.

‘(3) The complex of schist and serpentine has been folded after
the banding was produced, and before the dykes were intruded.
Some, if not all, of this folding probably took place when the com-
plex was formed.’

Of these the second and third alone are important, because without
them the first, so far as I understand the word ‘ complex,’ commits
us to very little.

In this locality also the question between us is one of interpreta-
tion rather than of facts. I gladly avail myself of the opportunity

* Quoted from notes written on the spot.

? Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 200.
3 Ibid. p. 210.

32 PROF. T. G. BONNEY ON THE [Feb. 1896,
of expressing my admiration of the map published in Messrs. Fox
and Teall’s paper.! The making of it must have been no easy task,
for the slope is very irregular, broken, and sometimes not the place
for an unpractised climber. So accurate are both it and their descrip-
tion that I had no difficulty in following them step by step in going
over the ground. This, then, is how I interpret the sections.
Nowhere in the serpentine can I find any of those symptoms, so
familiar to me, which indicate that after solidification it has
been subjected to severe mechanical disturbances (dynamo-meta-
morphism. The two cases, figured by my friends * (and the number of
such is small), appeared to me due to a different cause. The intru-
sion of a hot viscid mass into one already solid suffices sometimes
to bend either the latter locally or pieces of it which have been torn
off. Here there is no sign of the two rocks being folded as solids.
Furthermore, here and there, the serpentine includes slabs of
hornblende-schist of normal aspect, or the junction of the two rocks
may be often seen (as will be presently described), to be perfectly
welded and yet distinct. In one case (fig. 9) the serpentine runs up to
the broken edges of a wedge-
like projection of the horn-
blende-schist. In the latter
rock the banding is regular,
only a little rumpling and
flexure being perceptible at
two places, which are respec-
tively 2 feet and 4 feet in a
line from the point of the
former rock, while the mass as
a whole is not affected. The
disturbance, in short, reminds
one of the crumpling which
might be produced by thrusting
the thicker end of a flat paper-
knife between the pages of a

Fig. 9.—Banded hornblende-schist
in serpentine, Potstone Point.

The dotted rock represents serpentine,

tightly-closed book. The ser-
pentine in parts of this ‘ com-
plex’ appears to be sometimes

the lines indicate diagrammatically
the banding of the hornblende-
schist.

impure and harder than it
ought to be; often it is streaked like a brownish slag, while here and
there a thin band can be discovered, which resembles hornblende-

1 Quart. Journ. Geol. Soc. vol. xlix. (1€93) p. 203 (I had it with me as I
worked). Once or twice I felt doubtful about the small faults, and should have
made a slight change as to a dyke; but these are insignificant details, and I,
not they, may be wrong. * Op. cit. p. 212,

8 Which explains figs. 1 and 2, op. cit. p. 202. Under these circumstances the
junction-surface of the two rocks might be ‘ wavy,’ and ‘for every tongue of
serpentine into schist [there would be]....a corresponding tongue of schist
into serpentine.’ In such cases also the two rocks would probably exhibit a
parallel foliation. This does not appear to have occurred to my friends, and I
find no evidence that they minutely investigated the structure of the serpentine,
in which, however, the key of the position is to be found.

Vol. 520] ROCKS OF THE LIZARD DISTRICT, 33

schist, and seems to pass rapidly into the adjoining serpentine.’ In
the field I came to the conclusion that the latter rock had intruded
into the former, occasionally breaking off pieces of it and even locally
melting them, wholly or in part. Let us then see how far this con-
clusion is supported by study with the microscope. Taking first a
slice cut from a specimen which showed (as I supposed) a junction of
the serpentine and hornblende-schist, I find that the greater part
consists of a serpentine (mineral) of a brownish or greenish-orange
colour, exhibiting a structure which, if this were an acid rock, I
should not hesitate to claim as fluxional. In this groundmass are
scattered clear grains of a mineral without definite external form or
any well-marked cleavage, which, however, I think may be identified
as a hornblende, together with one crystal of a serpentinized bastite,
including rods of a monoclinic pyroxene. Besides these are numerous
granules, often aggregated, of a fairly translucent brown mineral;
some, doubtless, are picotite, but others, which exhibit double refrac-
tion, are probably hematite. This part is succeeded by a streak rich
in pyroxenic grains, many of them light brown in colour; and the
latter rock (sometimes after an intervening film of the former one)
changes to a band (slightly irregular in outline) consisting of felspar,
in a very decomposed condition,” of hornblende, warm brown in colour,
and of a moderate number of grains, which probably are a white augite,
though the mineral is rather ‘ dirty’ and sometimes serpentinized.
This band is about 1 inch wide, and the slice then is ended by a
serpentine like that already described. But on examining the hand-
specimen, this serpentine appears to be little more than a film, for
in not more than one-fifth of an inch we find fairly normal horn-
plende-schist. Next let us take two specimens from a part of my
friends’ section * near the porphyritic dyke. It is thus described in
my notes :—‘ A curiously banded and streaked rock, exhibiting fine
eompact bands and coarser-looking brown bands, in parts much
wrinkled and once or twice slightly brecciated, somewhat resembling
serpentine, but rather harder than is usual with that rock. I havea
strong suspicion that this is a mixture of serpentine and horn-
blende-schist, the latter being partly melted down by and carried
along with the former.’ Of one specimen, cut where the streaky
structure is much curved, one would claim part, without hesitation,
for hornblende-schist. It exhibits (Pl. I. fig. 5) the usual rather
granular structure, and consists mainly of a felspar, somewhat de-
composed, and hornblende, which, however, is brown instead of the
ordinary strong green colour. In other parts (streaks) we find the
grains of brown hornblende in a ‘matrix’ of composite microgranular

1 I suppose, of course, that the serpentine was a peridotite at the time of
the intrusion. This must be understood throughout.

2 It is whitish by reflected light, earthy brown by transmitted, and shows
specks of brightest colour with crossed nicols.

° Op. cit. p. 203 (map). I think it is from the part S and Sch below the
eo marked ¢. Whether this be the top of a ‘dome’ or not, I believe it to

an included mass, or, at any rate, to indicate intrusion on the part of the

serpentine.

Q. J.G.8. No. 205. D

34 PROF, T. G. BONNEY ON THE [ Feb. 1896,

minerals; in others this ‘ matrix’ is the orange-coloured serpentine

already mentioned. Other streaks consist of this serpentine with

rather small pyroxenic grains. All these varieties are associated in a

slag-like fashion (PI. I. fig. 6). A slice from another specimen, rather’
more serpentinous in aspect, exhibits a junction of two kinds of rock..
One presents the general structure of a hornblende-schist, but the

grains of that mineral are brown, while the others, instead of being”
felspar, are commonly a brownish-orange or greenish serpentinous:
mineral, which in some cases, when examined with crossed nicols,

resembles a bastite, in others prove to be a granular aggregate. The

other kind of rock exhibits a very marked fluxional structure in a

matrix (if one may so call it) which seems to be composed of minute:
doubly-refracting minerals, and its bands are darkest when parallel.

with the vibration-planes of the crossed nicols. Thisis spotted with

-a brown hornblende, which occurs both in granules and in grains of .
the usual size, and the above-named structure is almost at right

angles to a very slight parallel ordering of the grains in the other
part (Pl. I. figs. 3 and 4).

This, however, is not all. Let us examine a piece of hornblende-
schist which was included in the porphyritic dyke.’ It is a fairly
well-banded variety, thoroughly typical, except that it is a little
duller or of a more ‘greasy’ aspect than is usual.? Under the
microscope we find a rather marked difference between the bands.
Those which are lighter coloured in the hand-specimen, and are
spotted with white in reflected light, consist of a very decomposed
felspathic mineral, and of pyroxenic minerals, some (the less nume-
rous) brown hornblende, others a pale green rather fibrous hornblende,
and yet others consisting of aggregates of minute minerals. In
certain bands the brown hornblende dominates, and some felspar still
remains, while in yet another band the granular structure has.
wholly disappeared, and the rock consists of numerous colourless
flakes or prisms (about :02 inch long), which have the extinction of
actinolite, and are set in a mass of smaller flakes, probably, in part
at least, a white chlorite. Here then a specimen of hornblende-
schist, once normal, which has been affected by ‘ contact-metamorph-
ism,’ unites the characteristics to which I have just called attention
and those mentioned in our last paper,’ as belonging to supposed

1 A specimen of this dyke, taken from close to the included hornblende-schist,
has been examined with the microscope. In one part of the slide there are
indications of mechanical disturbance. This, however, is almost certainly due
to some accidental cause, such as a slight faulting, which escaped notice in the
field; for the porphyritic felspars are uninjured, and the other parts exhibit a
hypophitic structure. The felspar is generally decomposed, and the augite has
been replaced by a dirty-looking secondary product, which shows a composite
structure with crossed nicols. The rock is readily distinguishable from the horn-
blende-schist.

2 Its specific gravity is 2°917, that of a speckled variety from 8S. of Kileobben:
Cove 2°986, that of a banded (epidotic) variety from Church Cove 3:074. The
specific gravity of the serpentine in this district is 2°730 (pit between Mullion
and Lower Predannack) and 2°766. The specific gravity of two of the specimens:
of the streaky rock described above is 2-935 and 2'954. This is significant.

§ Quart. Journ. Geol. Soc. vol. xlvii. (1891) pp. 472-783.

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 35

cases of contact-metamorphism produced in hornblende-schist by
serpentine.

But before quitting this subject I must again refer to the locality
near Pare Bean Cove, north of Ogo-dour,' where I have already
asserted the serpentine to exhibit true intrusive junctions. Again,
perhaps for the fifth time, I studied this rocky slope with scrupulous
care. Here the serpentine has forced itself in a rather irregular
fashion through hornblende-schist, though it conforms on the
whole to the banded structure in the latter rock, slabs of which
appear occasionally to be broken off by and caught up in the
serpentine.” In this part the serpentine, which is sometimes
streaked, and in which the bands occasionally present some resem-
blance to hornblende-schist, is very rotten, but at a short distance
the rock is in better condition. A few yards to the west of this
complicated area,’ a gully exhibits the junction of the principal
masses of serpentine and of hornblende-schist. Here, as shown in
the annexed figure (10), a slab of hornblende-schist is separated
from the main mass by a ,

‘sill’ ofserpentine. Thisslab, Fig. 10.—Gully north of Ogo-dour.
where it was drawn, was about Intercalation of serpentine and
32 inches thick, and it tapers hornblende-schist.

away in a yard or so to less
thaniZinch. That the horn-
blende-schist about here is
the ordinary rock cannot be
doubted; it exhibits both the
‘dioritic’ and the ‘banded’
varieties. The serpentine,
generally more or less decom-
posed, is a little ‘platy’ in
the direction of and parallel
with the junction-surfaces, but
this structure is in no way
suggestive of crushing. The
serpentine also is occasionally

harder than is usual and looks 1=Hornblende-schist (more or less
impure. It is locally streaked, 4 _p spe ently ze

alternately warm brown and Serpentine dotted.
brown-black in colour. When

the included hornblende-schist becomes very thin—say not more
than an inch in thickness,—it is sometimes difficult to fix upon the
exact line of junction, but where it is thicker, this is generally
sharply defined, and the weld between the two rocks is perfect.

I have examined a specimen of this streaky serpentine (obtained
from near a weld) under the microscope (PI. I. fig. 1). The darker

* Quart. Journ. Geol. Soc. vol. xxxix. (1883) p. 22, and vol. xlvii. (1891)
p. 470 (with General M*Mahon).
2 The bands occasionally are cut across by the serpentine.
° It could only be accurately mapped on a very large scale-map, and the
trouble of doing it would not be repaid by the result. :
D

36 PROF. T. @. BONNEY ON THE [Feb. 1896,

bands consist of a very pale green serpentine thickly speckled with
opacite or streaked with clusters of the same substance ; the lighter
of the orange-coloured serpentinous mineral, mentioned above, of a
colourless, but rather ‘dirty’ pyroxene,' and of barely translucent
brown granules, in part at least iron oxides, more or less hydrous.
In short, this rock in parts closely resembles the serpentinous
portions of the Potstone Point specimen.” I have also examined a
specimen of the hornblende-schist in contact with the serpentine.
The fragment—from the face of the mass on the left hand of the
figure—is about an inch thick. Beginning with the part farthest
from the other rock, we find a band from 7 to 3 inch broad, which
exhibits a granalar structure like that of an ordinary hornblende-
schist, the hornblende being roundish in outline and brown in
colour, and the other grains composed of an ‘ earthy’ material, no
doubt replacing felspar, which, indeed, here and there can be
recognized. A thin lighter-coloured band succeeds, still containing
grains of brown hornblende, but with a more fibrous structure in
the intervening material. This is followed by a generally similar
layer, in which, however, the hornblende-grains are paler in
colour, though, with the polarizer, they exhibit a brown pleo-
chroism. In the remaining part of the slide (about 4 inch) the brown
colour of the hornblende-grains is less conspicuous, and they are
sometimes embedded in a pale-green fibrous mineral. The interval,
in short, between the grains everywhere appears to be a variable
mixture of minute minerals, of a more or less fibrous habit, among
which I think actinolite and serpentine may be recognized, and
near the very edge, where the grains of hornblende become less
frequent, are dull orange-coloured patches, perhaps only staining, and
the rock becomes more definitely fibrous. Granules of iron oxide,
as might be expected, occur here and there in the slice.

Another specimen, from a part of the adjacent hillside, where
the serpentine appears to have forced its way between two slabs of
hornblende-schist and to include a little streak of the latter, is very
interesting. This streak is about an inch thick, and the slice has
been cut through it (Pl. I. fig. 2). Beginning on one side we find
a greenish, orange-coloured serpentinous mineral, in which are
scattered more or less acicular microliths of a colourless hornblende.
As these microliths increase in number,'the former mineral is re-
placed by a more or less distinctly fibrous one, though the transition
between the two kinds of rock is rather abrupt, as in the case of
fluxional streaking ; then comes a brownish hornblende, rather more
granular in habit, associated with a colourless mica-like mineral,
probably a chlorite. Lastly, the hornblende-grains, still generally
composite in structure, but becoming larger and more definite, are
parted by earthy spots like the residue of felspar, and from this

1 Probably white hornblende, for the mineral occurs in all the serpentine of
this neighbourhood. .

2 The specific gravity is 2°539, that of the Predannack serpentine, as
already stated, being 2°766, but the difference is probably due to decom-
position,

Vol. 52. ] ROCKS OF THE LIZARD DISTRICT. 37

condition, as we approach the other edge of the slice, we pass back,
speaking in general terms, through the conditions already described.

I have again examined the sections at Henscath, Carnbarrow, and
in Porthallow Cove. As regards the first and second, I could fill a page
with minute descriptions, but may coutent myself with saying that
I found it impossible to explain what I saw, either by displacements
due to earth-movements, or by the flowing together of differentiated
magmas, or by anything else than the intrusive action of the
serpentine on the hornblende-schist, after the latter had become
solid. As for the Porthallow sections, it may suffice (except in
regard to one interesting detail) to refer to what has been already
published, and to copy the words which I wrote on the last occasion
in my journal :—‘‘ Some of the cases here are inexplicable to me on
any hypothesis other than that of an intrusion of the serpentine into
the schist. It may be said that ‘ the two have flowed together,’ but
the serpentine sometimes cuts across the edges of bands in the other
rock in a way which suggests direct fracture and not the result of a
strain-slip. The serpentine may indeed sometimes bend with the
bands, but that proves no more than that the schist (like the included
fragments of gabbro near Manacle Point) has been somewhat softened
and made flexible. The bending cannot be attributed to subsequent
earth-movements, because the serpentine does not show the slightest.
sign of crushing, and the weld between the two rocks is often perfecs.”

But an examination of the specimens collected on this occasion has
enabled me, as the result of the whole work, to clear up a difficulty
which this Porthallow serpentine hitherto had presented. We find
here and there in it, close to junctions with the hornblende-schist, grey
bands, which are intermediate in aspect and hardness, Is this a less
pure variety of serpentine, a streak of picrite, which, as indicated by
the analysis, is present in the rock ? and, if so, how can we explain
its presence?* I had hitherto vaguely referred it to some
differentiation in the magma, but can now offer a more precise
explanation, in accordance with the cases already described. I
brought away a few specimens for further investigation. One of
these, about 43 inches long, consists mostly of the ordinary
Porthallow serpentine (a little redder in colour than usual) ; the
remainder, a band about an inch thick, is of a greenish-grey colour,
and this was in contact with, though here not welded to, a dark-
grey, minutely speckled rock, which in hardness and general aspect
agreed with a hornblende-schist. The latter, on examination with
the microscope, exhibits traces of a banded structure; in some
bands are residual grains of felspar, and with them grains of brown
hornblende, but the greater part of the rock consists of flakes or
longish prisms of actinolite in a felted mass of the same or of a
colourless chlorite. The red part of the other specimen is a fairly
normal serpentine (Porthallow type). It consists chiefly of the
peculiar orange-coloured granular serpentine (mineral), often much
stained with hematite, the latter also occurring in minute rods,

* See paper by Gen. MtMahon and myself, op. cit. pp. 471-475, and table
of analyses (facing p. 466).

38 PROF, T. G. BONNEY ON THE [ Feb. 1896,

and of small elongated prisms of colourless hornblende. It contains,
however, a number of small ‘ inclusions,’ consisting almost wholly
of clustered ferrite, surrounded by a clear zone, not quite so broad
as they, of actinolite; and two larger inclusions (?), much ferrite-
stained, recall the structure of a fluxion-breccia. This part of the
slice is separated from the grey band by a rather sharply defined
border. The latter affords indications of a banded structure in the
presence of ill-defined lines of brown hornblende-grains (not
numerous), of felspar(?)-grains, and (chiefly) of a felted mass of
flaky or acicular actinolite, with which probably a colourless chlorite
is also associated. These specimens, with that from Pare Bean Cove
described. above, lead me to the conclusion that their adjacent faces
indicate the junction-surface of the two rocks, but that here also
the outer part of the serpentine has been rendered impure by some
superficial melting of the hornblende-schist.*

The facts cited above, it may be worth while to repeat, seem to
indicate that the brownness of the hornblende’® is one indication
of contact-metamorphism, while a more extreme result of the
latter is the production of a rather fibrous, somewhat minute
actinolitic hornblende and of sundry flaky minerals (representing
the aluminous constituents of the rock), probably light-coloured
chlorite or mica.

Here I may refer to a section which has been mentioned more
than once in former papers,* namely, that exhibited in a low crag
at the foot of the main cliffs, north of Kynance Cove. On each
visit I have spent some time in studying it, without, however,
feeling much more certain as to its exact interpretation. As
described on the first occasion, serpentine occurs on either side, and
in the cliff above, the craglet in question, which exhibits, apparently
in vertical bands, “ (2) a mass of grey, rather sandy, ‘ hornblende-
schist,’ about 8 feet thick, with apparently many thin lamine of
red serpentine; (3) red serpentine, rather fissile in structure,
23 feet; (4) a dark brownish-grey rock with crystals rather
resembling diallage, 2 feet; (5) red serpentine, 42 feet, divided by
a thin [rather wedge-shaped] band of the schist, then bedded
schist like (2), with the apparent layers of serpentine, for about
6 feet.” *

1 It may be well to remark that the serpentine of the Lizard is generally
very uniform in structure, and only departs from this rule (and that by no
ene always) in the immediate neighbourhood of a junction with hornblende-
schist.

2 I have more than once called attention to the fact that in hornblende a
brown colour often precedes the green ; the latter may indicate an early stage
in the process of hydration, affecting the ultra-microscopic grains of iron oxide
or some constituent to which the colour is due.

5 Quart. Journ. Geol. Soc. vol. xxxiii. (1877) pp. 888, 920; vol. xxxix.
(1883) p. 28.

4 «Rather more than 7 feet’ was my note in 1894; the measurements then
were a little more precise than on former occasions, but the differences are 80
slight that I leave the passage as it stands. Between the last-named ‘schist’
and the serpentine (5) is a thin darkish dyke, which I had supposed to be part
of the schist, and there may be another in the latter.

Wol. 52.] ROCKS OF THE LIZARD DISTRICT. 39

Afterwards I described the microscopic structure of the rocks,
pointing out that the serpentine is an unusually compact variety, and
stating that I regarded the mass as representing a block of horn-
blende-schist, caught up by the serpentine, altered thereby, and
probably since then further changed by the action of water. In
‘the 18 years which have elapsed since I wrote these descriptions,
my experience has been considerably enlarged, yet I still find the
rock numbered (4) a very perplexing affair. I note that it is
sporadically porphyritic, that the larger crystals under the micro-
scope appear to exhibit traces of ‘ lustre-mottling,’ that the
wedge-shaped piece included in the serpentine (5) is almost
certainly a more compact variety of the same rock, and that this
may have been a picrite ; also that the serpentine is probably the
intruder. But I can now throw a little light on the banded
structures, which are among the perplexities of the section. On
examining the dyke-like serpentine (3) I found that towards the
edges it gradually became banded. This structure on the right-
hand side began to be indicated about 2 inches from the exterior,
but only became very marked in the outer inch, where a grey tint
predominated. The red part, on microscopic examination, is found
to owe its colour to hematite-staining, and to consist of a
serpentine (mineral) thickly crowded with minute flakes of a clear
mineral, many of which give oblique extinction, and resemble actino-
lite, but others give straight extinction, being probably a chlorite.
The last inch, however, is practically colourless (only spotted with a
few grains of iron oxide), consisting of matted flakes, quite double
the length of those in the other part, but the same minerals. The
edge of the serpentine (5), where it is in contact with the small dyke,
exhibits a band about } inch wide. The red part resembles that
described above, except that it seems to be a rather purer serpentine,
and it contains one or two ill-preserved grains of bastite, while the
band itself consists of a streak of fairly clear orange-coloured
serpentine, followed by the matted minerals just mentioned, in
which a kind of bandlet is formed by some small grains of brown
hornblende, with a little streaking of serpentine. I have also
examined a piece of the dyke, which is in contact with this face of
the serpentine. Probably it was once a basalt; it has consisted
mainly of two minerals, each of which has been replaced by
secondary microliths: the clearer patches probably representing a
felspar, the others almost certainly a pyroxene. But attached to
this is a zone, which in the field I thought might represent a
junction. This bears a considerable resemblance to part of the
border in the other specimen, for it consists of a matted mass of
acicular minerals, some being considerably larger than the rest
and distinctly actinolitic, in which one or two grains suggest the
possibility of having been bastite. Besides these I have examined
‘a piece of the striped red-and-grey rock (the supposed schist) in the
left-hand part of the crag, where the bands locally are sharply
folded. The red rock is a serpentine, like that already described ;
the grey one is a mass of microliths, generally too minute for iden-

40 PROF. T. G. BONNEY ON THE [Feb. 1896,

tification, but here and there in it are zones of larger flakes, in part:
at least actinolitic, spotted with grains of hematite and of a
pyroxene, in some cases certainly hornblende.

Whether the whole of these two masses, which I formerly
supposed to be mainly altered and decomposing hornblende-schists,.
consists of serpentine streaked with bands, which are more nearly
picrites in composition, it would be impossible to say without
another and yet more minute examination, and this, perhaps, after
all would hardly repay one for the trouble ; for it is now clear that:
this section affords a conspicuous instance of a banding in the
serpentine itself. As to the two larger, apparently included, masses.
of ‘ brownish-grey ’ rock, I incline to regard them as pieces of a
picrite, rather than as exceptionally altered fragments of the horn-
blende-schist, but in the present state of my knowledge cannot:
venture to speak more positively.

V. CoNncLuUsIoNs.

I submit, then, that the facts described in this paper justify the
following conclusions :—

(a) Mechanical forces, due to earth-movements, have only rather
locally produced important effects on the crystalline rocks of the
Lizard: namely, in a very limited area at Porthallow, near the
great boundary-fault, and over a larger one in the south, approxi-
mately bounded by a line drawn from a little east of Polpeor to
rather south of Caerthillian Cove.’

(6) Elsewhere the results of such forces are of very secondary
importance, being restricted to the neighbourhood of faults, and
even there producing commonly very limited effects.

(c) The slightly foliated or linear structure rather common in the
serpentine, its occasional distinct banding, together with rather
similar structures in the gabbro and a faint approach to them in
certain basic dykes, as has been more fully shown in the paper by
General M*Mahon and myself, have nothing to do with ‘ dynamo-
metamorphism, but have been produced by fluxion-movements
anterior to the complete consolidation of the rock.

(ad) The serpentine is intrusive in the ‘ granulitic group,’ which,
however (though it may have torn off large blocks), it has
only locally softened and indented. It is also intrusive in the
hornblende-schist, but this it has sometimes riven, and occasionally
melted down, in certain cases partially, in others perhaps wholly,
thus producing the streaks of a less pure character, with some
resemblance to the former rock: these phenomena, as might be
expected, being restricted to the exterior of the mass, the rest of it
generally exhibiting an uniform character for considerable distances.

In short, though the effect of twelve years’ work in the field and
with the microscope has caused me to change my views as to the

1 An area very nearly correspondent with that assigned to the ‘mica-slate
series’ of Sir H. De la Beche. The line, if it runs straight (I have not attempted
to trace it), would be roughly from N.W. to S.E.

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 41

genesis of the ‘granulitic group’ and the hornblende-schists, I adhere
(except in regard to a few matters of detail) to the conclusions
which were expressed in my paper published in 1877, and more
emphatically than ever to those expressed in the first three of the
above paragraphs—namely, that I can find no ground for attributing
the foliated or banded structures, whether in the granulitic and the
hornblendic groups or in the serpentine, gabbro, and a few basic
dykes, to dynamo-metamorphism. As regards the banding of the
granulitic and hornblendic rocks, I can only say that if it be due to
any kind of shearing in solid heterogeneous materials—it is not easy
to follow mentally the steps of the process—recrystallization has been
so complete that the usual indications of such action have vanished.
Hence the structure must have been produced anterior to the incoming
of the serpentine and the gabbro. Yet, if the serpentine were folded
together with the granulitic rock so as to distort its bands, traces of
crushing and shearing should be found in the latter. Even if we
assume these to have disappeared (which I could not admit) and
claim the foliated and banded structure occasionally exhibited by the
gabbro as a result of dynamo-metamorphism, what is the testimony
of the serpentine? It is sometimes welded to the granulite, often
to the hornblende-schist ; it is constantly cut intrusively (every-
body, I believe, grants this) by dykes or veins of gabbro. But the
serpentine almost invariably shows no signs of crushing. Strain and
pressure might destroy a weld, but I never knew them produce one
between rocks of this kind; hence the foliation and banding of the
serpentine cannot be due to any such cause.’

- But serpentine is a much more brittle rock than granite, horn~-
blende-schist, or gabbro; the last, as one quickly learns in the
Alps, being a very obdurate material. Hence earth-movements, which
would affect these rocks, would leave their marks distinctly enough
on the serpentine. This is a brief summary of my observations in
regard toit. Under strain, perhaps under moderate pressure, serpen-
tine simply brecciates*; when the pressure becomes more severe
the rock breaks into pieces, which are generally rather lenticular
in shape, with a ‘glaze’ on the outside,’ and, as a final stage of the
‘peine forte et dure,’ the serpentine becomes so slaty that it might
be sometimes used for roofing purposes.* The Alps afford many

1 On this point I am not afraid of being accused of speaking dogmatically.
My first visit to the Lizard was in the autumn of 1873, and I speedily fell a
victim to the fascinations of serpentine, probably because I found it to bea
subject where quot homines tot sententie held good. I have never felt strongly
attracted to beaten paths. Since then I have studied serpentine (including
peridotite) in the field on an average once ina year. I have returned five times
to the Lizard, I have been thrice to Anglesey, I have examined the rock in
three districts in Scotland, in at least a dozen separate localities in the Alps (in
some cases not only as a passing traveller), in two districts of the Apennines,
and in the Pyrenees, besides studying with the microscope specimens collected
expressly by myself, with many others acquired by gift or by purchase. The
effects of earth-movements also are not novel to me, since for more than a
dozen years I have been studying these in the Alps and elsewhere.

? Geol. Mag. 1879, p. 365.

3 Ibid. 1880, p. 588, and elsewhere. 4 Ibid, 1890, p. 533.

AQ PROF. T. G. BONNEY ON THE [ Feb. 1896;

opportunities of studying these changes. Towards the outside of a
large mass, in a region which has undergone severe pressure, one may
find the ‘lenticular’ structure, and it is vain to hope for a decent
specimen, but as we pass inward the rock often becomes less |
brecciated, so that at last fairly normal specimens may be obtained.
Even the slaty structure may not affect the whole of a large mass ;
now and again portions of it escape comparatively uninjured. Of
this, however, we may be sure, that if a force had acted sufficient
to produce a marked effect on either the granulite, the hornblende-
schist, or the gabbro, the serpentine would have been almost invari-
ably torn apart from the weld, and would have been crushed, perhaps
to a slate, for at least a considerable distance from the junction.’
If, then, the relations of the serpentine with the granulites and
the hornblende-schists indicate an ‘ igneous complex,’ if its structures
and those of the gabbro are the results of dynamo-metamorphic
action on the rocks when they were solid, the Lizard district
flatly contradicts everything which I have learnt about rock-struc-
tures during more than twenty years of work in the field and of
studying under the microscope specimens collected with my own
hands.

VI. APPENDIX.
(a) Miscellaneous Notes.

It would be a very long task to examine every rock in such a
. district as the Lizard, so that even in going over ground compara-
tively familiar one picks up ‘crumbs’ of information, some of
which may. be worth a brief record.

Dykes.—A porphyritic diabase, as described by Messrs. Fox and
Teall, and by Gen. M°Mahon and myself, is occasionally found,
usually in rather thin dykes. Those hitherto recorded, if not actually
confined to the hornblende-schist, are closely associated with it, as
near Potstone Point,” but we came upon one cutting through ser-
pentine (the variety with small crystals of colourless hornblende)
near the path* leading from Mullion Village to Predannack
Wartha. The hornblende-schist, near the western end of the cliffs on
the northern side of Porthoustock Cove, is cut obliquely by a yel-
lowish rock, generally rather decomposed, which, though only a few
inches thick, is more like a dyke than an infiltration-vein. I find
this on microscopic examination to exhibit a finely granular struc-
ture not resembling any of those usual in veins, and to consist of
epidote. This mineral no doubt readily forms as a secondary
product in rocks of suitable composition, but the uniformity in
composition is a little strange. Such an epidosite would come most
readily from arock composed of a lime-felspar with some minutely

1 The effects of pressure are never more conspicuous than in the weaker of
two rocks near the junction-surface. y

212, 3)

3 It is about 350 yards, in a line drawn rather N. of E., from Oreggian
‘Mill; in the same direction are two other shallow pits in serpentine.

Vol. 52.] ROCKS OF THE LIZARD DISTRICT. 43

disseminated iron oxide. Two or three dykes of coarse gabbro,
very poor in the ferro-magnesian silicates, have indeed been
observed on the coast farther south; can this epidosite have been
a very compact variety of the same rock?

Manacle Point and Porthoustock Cove-—We can add a few notes
to the description given by Gen. M*Mahon and myself... The
ordinary gabbro (which forms the Crousa Down massif) when
followed along the shore towards Manacle Point, passes occasionally
into a very coarse variety, in which the constituent crystals some-
times even exceed 2 inches in length. This forms patches in the
ordinary rock, with ill-defined boundaries, suggestive of an imperfect
mixture of heterogeneous materials in different stages of consolida-
tion. Other parts of the gabbro are foliated, and these occur in
like manner, so as to suggest local movements anterior to complete
consolidation. The ‘warm grey’ or brownish rock intrusive in
the gabbro,” especially as Manacle Point is approached, would
repay a closer study than our arrangements allowed us to give it.
It pierces and rips up the ordinary gabbro in a very curious fashion,
and pieces of the latter sometimes assume singular shapes, as if they
had been slightly softened and bent (fig. 11). Frequently, also, it

Fig. 11.—Strip of moderately coarse gabbro included in granular
dolerite (or gabbro), south of Porthoustock Point.

The unmarked part indicates the latter rock. The sketch is diagrammatic.
The inclusion represented measures nearly 2 feet from end to end.

includes flake-like fragments of the foliated variety.? Besides this,
it rather often exhibits a porphyritic structure, the mineral being
commonly felspar, but sometimes a variety of pyroxene, which
forms green spots. The felspar-crystals are a dead-white colour,
like that in the gabbro, ranging up to about half-an-inch in length.
They are ‘ sporadic’ in habit, occurring in small ‘ swarms,’ some-
times more or less scattered. Sometimes, also, they are actually in
contact, and it becomes difficult to distinguish them from the smaller
rock-fragments. Occasionally a felspar, as it appears at first, proves
on examination to contain a speck of diallage. In short, the

* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 491.

* It is noticed on pp. 491 and 494 in the paper by Gen. MeMahon and
myself. As there stated, it is a kind of dolerite or fine-grained gabbro.

* The bearing of these observations on some of the reasoning in the earlier
part of this paper will, I presume, be obvious.

44 PROF. T. G. BONNEY ON THE [Feb. 1896,

intrusive finer-grained rock seems to have softened, bent or drawn
out some fragments of the coarser gabbro, and even to have partly
melted down others, destroying the pyroxenic rather than the
felspathic constituents, so that the latter are scattered sporadically
in the newer rock.’ Prof. Sollas, it will be remembered, has
described a somewhat similar occurrence in the Carlingford district.”
This intrusive rock is less abundant than the ordinary gabbro, but
more so than the ‘ greenstone’ * dykes, which cut them both, and
usually do not exceed 4 or 5 feet in thickness.

A low spring tide enabled us to make a more complete examina-
tion of the southern side of Porthoustock Cove. As mentioned in our
paper (p. 491), General M*Mahon and myself felt uncertain as to
the nature of the rocks forming the shore and adjacent cliffs. They
presented, as we remarked, some resemblance to the more dioritic
members of the ‘granulitic group,’ and were cut by ‘ greenstone’
dykes, like those mentioned above, the gabbro being near at hand;
for we traced it on the slopes above the cliff almost to the head of
the cove.* This time we managed to get along the shore eastward,
to a point where the ordinary gabbro was exposed in the face of the
cliff. Here the rocks on which we stood consisted beyond question
of the fine-grained gabbro or dolerite, becoming, as usual, sporadic-
ally porphyritic in the neighbourhood of the coarser rock, and from
this point we succeeded in following it westward, and convincing
ourselves that, though somewhat disguised by the effects of faulting
and weathering, it is the dominant rock on this side of the cove.
It is cut, as has been said, by ‘ greenstone’ dykes, and traversed.
not unfrequently by reddish veins. Some of these appeared due vo
infiltration, but others resembled a rather felspathic gabbro, by no
means identical with that forming the principal massif. Thus
Porthoustock Cove marks the position of a fault or group of faults,’
which brings together the Crousa Down gabbro, with its associated
inirusives, and the hornblende-schist.

Serpentine.— We examined the mass at Porthkerris ° more care-
fully than on former occasions. It is represented in the geological

1 Microscopic examination. confirms the statements made above, and
discloses one or two other facts of general interest. In the granular ground-
mass the felspars are generally fairly well preserved ; the pyroxenic constituent
was originally an augite, very pale brown in thin sections, which now, without
change of external form, is replaced by a brown, strongly pleochroic hornblende
(brownish straw-colour to rich brown). The felspar of the included fragments
is almost wholly replaced by secondary and mostly earthy material ; the augite
by fibrous, often felted, aggregates of a greenish actinolitic hornblende. Here
and there the included fragments are so minute that one can hardly identify
them with certainty.

? Trans. Roy. Irish Acad. vol. xxx. (1894) p. 477. The changes, however, in
this instance are different—probably owing to local cireumstances—from those
observed by him.

3 I use this vague term designedly, for they may be anything from a fine-
grained dolerite or basalt to a hornblendic diabase.

4 Still cut by the fine-grained gabbro or dolerite and by the ‘ greenstone.’

° The coves in the Lizard almost invariably correspond with one or more
dislocations.

6 Polkerris in earlier papers. In this I have followed the nomenclature of —

the 6-inch Ordnance map.

Vol. 52. ] ROCKS OF THE LIZARD DISTRICT, 45

map as coming down to the shore on the northern side of the cove;
but if there be an outcrop here, it was concealed on this occasion.
At any rate, I think it must be isolated from the main mass of the
serpentine; this crops out in many places on the moorland which
rises on the northern side of the little valley, being seen over an
area measuring about 200 yards from east to west, and not more
than this in a transverse direction, hornblende-schist cropping out
south, east, and north of it. Whether this mass of serpentine is
continuous with the one at Porthallow we could not determine, the
two being separated by rather more than a furlong of covered ground.
Macroscopically it agrees fairly well with one variety of that rock,
but it is perhaps a little smoother in aspect and brighter in colour.
It has been much cracked and then cemented by yellowish
steatite, so that it is apt to break up under the hammer. The two
rocks agree fairly well in microscopic structure, each resulting from
the alteration of a fine-grained peridotite, which appears to have
consisted simply of olivine and iron oxide (7. ¢. a kind of dunite).’
We ascertained that at Porthallow the serpentine not only runs
up the cliff in a dyke-like fashion, but also does this at each end, so
that the shape of the mass might be compared—very roughly—to a
flattish crescent with its back to the water.” The quarry afforded
better sections than it had done for some years. I can understand
doubts arising about the interpretation of particular sections, but
not as to the general fact that the serpentine is intrusive in the
hornblende-schist.

We again paid much attention to the structure in the serpentine
resembling a foliation, which may be observed in many places,
more distinctly on the western than on the eastern coast, though on
the latter also, as from Kildown Point to Kennack Cove, it is often
to be found. Frequently it is barely perceptible on a perfectly fresh
face of the rock, becomes visible on wave-worn surfaces, and is
quite distinct on weathered crags. It obviously proceeds from a
slight alignment of the constituents in the original peridotite, and in
the case of bastite-serpentine seems more especially determined by
that mineral. While it is not seldom fairly persistent in orientation
over considerable areas, marked changes in direction may be
observed; and while in the neighbourhood of included masses of
granulite it is sometimes parallel with the junction-surfaces, cases
not unfrequently occur where it makes a high angle with them.
In other words, we have failed to discover any necessary relation
between the structures in the two rocks. The serpentines in which
this ‘foliation’ exists do not exhibit, macroscopically or micro-
scopically, any indications of strain or crushing, and I adhere to the
opinion expressed by Gen. M°Mahon and myself,* that the structure
was produced while the original peridotite was consolidating.

1 [refer to the ordinary serpentine of Porthallow, regarding the banded
variety as exceptional,

2 The slopes here are steep, rough, and much overgrown with brambles and
coarse herbage, so that it is not easy to map the outcrops, and we have not
attempted to do this very precisely.

3 Quart. Journ. Geol. Soc. vol. xlvii. (1891) pp. 447, 476.

46 PROF. T. G. BONNEY ON THE [Feb. 1896,

We have already pointed out’ that the Lizard affords two fairly
distinct types of serpentine — one, that more generally known,
containing distinct. grains of bastite (¢. g. Kennack Cove), and
sometimes augite in addition (¢. g. Coverack Cove); the other, in
which the bastite, if present, is inconspicuous, while small crystals
of white hornblende are abundant (¢. g. south of Mullion Cove); the
former being most abundant on the eastern, the latter on the western
coast.” But we find the bastite-serpentine on the west coast to the
south of Kynance Cove,’ and again on the actual headland of the
Rill. Here, also, within a short distance, the peculiar variety
of serpentine occurs which has been said to contain felspar,* but I
could not discover how they were related. From north of Kynance
to Gue Graze the dominant serpentine is a rather compact, slightly
streaked rock, which on the whole seems more nearly related to the
hornblendic than to the bastite-serpentine. The hornblendic ser-
pentine also occurs, though not abundantly, on the east coast ; that
at Porthallow ° on the whole more nearly agrees with it than with
the other ; we find it on the shore for some little distance south of
Poltesco Cove and from Cadgwith to Carnbarrow. But the most
curious instance is at Kildown Point. In the quarry at the top we
find the bastite-serpentine, while the mass at the foot of the cliff ®
is a very typical hornblende-serpentine. I regret that I have not
from the first recorded the variety of serpentine in each quarry or
outcrop examined; but, so far as I remember or have noticed, the
serpentine, at places within a curved line drawn from Coverack to
Kynance Cove, roughly symmetrical with the eastern coast, is
generally the bastite variety, and that outside this line is the horn-
blendic variety, including with it the dull compact type already
mentioned. .

Green Schists of the Southern Coast.—We paid special attention
to the relations of these schists with the normal hornblende-schists,
and are more than ever satisfied that, as stated by Gen. M°Mahon
and myself, they are only the latter rocks modified by extreme
pressure.” In more than one place we were able to trace a gradual

1 Quart. Journ. Geol. Soc. vol. xxxix. (1883) p. 23, and vol. xlvii. (1891)
pp- 466-468.

2 Sp. gr. (mean) of four specimens of the former (two determined for this
paper) soe Sp. gr. of three specimens of the latter (two determined for this

aper) 2°755.

E P <u in the sections near the Lion Rock, described by Messrs. Fox and Teall.

4 I remain sceptical as to the identification of this mineral with felspar,
though I believe it to be an aluminous silicate.

5 Its sp. gr. ranges from 2°545 to 2°644 (J. H. Collins); that of the Rill is
heavier, 2°74; that of Gue Graze heaviest of all, 2°85 (M. W. Travers),

6 See p. 30. The sp. gr. of a serpentine such as that at the top is 2°653, of
that at the bottom is 2-698, which is very nearly that of the west coast serpentine.

7 In regard to this my work in the Alps during the last few years has been
very helpful; see Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 94, and vol. 1.
(1894) p. 279. [As this admission was quoted by a speaker in the debate to
justify the extension of ‘dynamo-metamorphism’ to the whole region, I must
point out that, by admitting a certain cause to have produced marked modi-
fications in two very limited parts of a district, we, in effect, exclude it from the

Vol. 52. ] ROCKS OF THE LIZARD DISTRICT. AT

change from the normal to the abnormal type. Still, the mass as a
whole exhibits a little more variety in composition than is usual in
the hornblende-schists. Gneissoid rocks occur in it, as near Old
Lizard Head and on the south side of Holseer Cove, and masses of
a brownish mica-schist at Polledan Cove (discovered by Mr. Fox),
Polpeor Cove, and in the headland south of Holseer Cove. This
last I bad not before observed. It is seen, under the microscope,
to consist of quartz and mica, mostly biotite, which, as in the
similar rock in Polpeor Cove, has evidently suffered from pressure,
and it contains grains, not very regular in shape, of a water-clear
mineral, evidently of secondary origin. This may be felspar, but
the refraction-index seems a little high for that mineral, and one or
two grains show a slight pleochroism (reddish), so I think it more
probably andalusite.

On the northern side also of Holseer Cove are two rather peculiar
rocks. One is a slaty, purplish-coloured rock, which is found, on
microscopic examination, to consist of grains of a clear mineral,
much of which is isotropic (? opal) with a greenish mineral,
extinguishing obliquely (probably a chlorite), ferrite, and opacite.
The mede of occurrence in the field suggested the possibility of an
intrusive origin, but I cannot say that the microscopic examination
throws any light on this question. Nor does it help us with a
purplish, slightly-streaked rock at the head of the Cove, which still
more resembles an intrusive mass. It consists of grains of the
above-named clear mineral, flakes of biotite, more or less altered, a
little white mica, grains of iron oxide, and a few very small garnets.
Both these rocks, whatever may have been their origin, are now
schists, and with that group we must leave them.

(6) Age of the Lizard Rocks.

Though I now think it more probable that the hornblendic as
well as the granulitic groups are not altered sedimentaries, but
peculiar forms of igneous rocks, 1 am more than ever convinced
that they are older, perhaps very much older, than the serpentine
and the other rocks intrusive in it—that is, I still consider them
to be Archean. It is needless to recapitulate arguments which
have been more than once stated in print, but I may say that
the resemblance of some of the gneissoid rocks of Sark and Britanny
to those at the Lizard, and the practical identity of the hornblende-
schists in the first and last localities, make it highly probable
that they do not differ materially in age. Now, the gneissoid rocks
of Britanny are older than the Cambrian, older even than the
‘Schistes de St. L6’; while it is almost certain that the hornblende-

remainder. This, I may add, is not the only instance in which a like incorrect
appeal has been made to the evidence of ‘dynamo-metamorphism’ at the
northern and the southern boundary of the district.—January, 1896.]

48 PROF, T. G. BONNEY ON THE [Feb. 1896,

schists of Sark, with many of the larger masses of crystalline rock
in the Channel Islands, are pre-Cambrian, so that my estimate of
the age of these rocks at the Lizard is not affected by any change of
opinion as to their origin. But what is the age of the serpentine?
It is older than the troctolite, the two varieties of gabbro, the
granite, and the various ‘greenstone’ dykes. The last-named,
indeed, may be very much younger than it; for some of them must
have cooled quickly, and occasionally seem to be very fresh. Rather
similar rocks, and the granite, elsewhere in Cornwall are certainly,
at least in many cases, post-Carboniferous.' So possibly may be the
“dyke-rocks’ at the Lizard. JI think that the serpentine, the
troctolite, and at any rate the coarse gabbro, must have followed
one another rather quickly; the finer gabbro, however, which
sometimes seems to become rather more compact near a junction,
may be separated from the others by a longer interval, for reasons
which I presume will be sufficiently obvious. But what is the date
of the others? The picrite at Menheniot, which presents resem-
blances to some varieties of the Lizard serpentine, is intrusive in
Devonian sedimentaries. This question, however, may be ultimately
solved by a careful study of the rocks at the Nare Head between
Gerran and Veryan Bays. I am indebted to Mr. Fox for my first
sight of this most interesting district, of which, however, owing to
unfavourable weather, I could only examine a very small part
(at Pennare Wallas). Here, going southward up the slope of a hill,
we found, first a slaty rock, then serpentine, then outcrops of gabbro.
The serpentine, in which a shallow pit has been opened, is much
crushed, so that it is difficult to obtain good specimens. It is, how-
ever, a dark bastite-serpentine,” very like that in Kildown and
Kennack Coves, allowing for the effects of pressure. But on the
northern side of this pit we find some of the sedimentary rock,
which, though much crushed, is evidently a slaty mudstone with
coarser bands, formed of materials which seem to have been derived
from crystalline schists. The gabbro is identical with that of the
Lizard, when the one constituent has become a kind of saussurite,
and the other hornblende. The sedimentary rock is doubtless
Paleozoic, although its exact age cannot be determined. The
junction here very probably is a faulted one, but so far as I
can learn, the crystalline schists do not appear in this district.
Thus it looks as if the serpentine had broken through the Paleozoic
sedimentaries. If this, on further examination, prove to be true,
then it will be highly probable that the Lizard serpentine also is
post-Archeean in age.

1 Or at any rate later than any Carboniferous rocks in that region. But they
are older than the rocks now generally regarded as Permian.

2 Its specific gravity is 2.579; that of a specimen from the above-named
locality is 2°647.

lel

Mintern Bros .imp.

3x12

Quart.Journ.Geol.Soc.Vol.LII .PI1.L

BANDED SERPENTINE AND PARTIALLY MELTED

oa

ao ae Se a

EH Michael. del.et lih.

HORNBLENDE-SCHIST.

Vol. 52. | ROCKS OF THE LIZARD DISTRICT. 49

EXPLANATION OF PLATE I.

Fig. 1. Intrusive serpentine, streaked brownish and blackish, from near Pare
Bean Cove (see fig. 10 and description in text, p. 35). @ is a band
of the orange-coloured serpentinous mineral ; the other bands (0) are
lighter in colour, but often speckled with a light puce-brown and with
opacite. The large dark grain is of a deep brown tint. (x 8.)

2. From a band of serpentine, intrusive in hornblende-schist, and including
a thin ‘ streak’ of the same, from the section described near Parc Bean
Cove (see description, p. 36). The part drawn represents the junc-
tion of the serpentine with the included streak of schist. a, film of
true serpentine, forming outer part of specimen; 2, fibrous minerals
—brownish hornblende, chlorite (?), ete. ; ¢, more granular brown horn-
blende, and dark ‘ earthy’ spots (decomposed felspar). (xX 8.)

3, 4. Junction of serpentine and hornblende-schist near ‘ Potstone Point.’
The two rocks, as described in the text, are ‘fused’ together. In order
to represent this better, 4 is in part a repetition of 3, the lower por-
tion of the former corresponding with the upper portion of the latter.
a represents the serpentine with a fluxional structure. It contains
grains of brown hornblende, which are more conspicuous near the
junction 0; ¢ is hornblende-schist (with brown hornblende), between
which is a greenish mineral, often serpentinous in aspect, as described
in the text (p. 33). (x 12.)

5. Serpentine interstreaked with hornblende-schist, which it has partly
fused, from Potstone Point (see p. 33). a, mostly a rather fawn-
or orange-coloured serpentine, including brownish hornblende, etc. ;
6, hornblende-schist with brown hornblende and earthy material
(the part dark in the drawing) representing the felspar. (x 9.)

6. Another specimen from the same locality, showing a more complete
interstreaking of serpentinous (a) and hornblendic (0) layers, as if the
two rocks had flowed together like aslag. (x 9.)

Discussion.

Mr. Tear said that, although he had visited the Lizard several
times, he had been unable to form any general theory as to the
structure of the district. He was glad to find that, so far as the
facts were concerned, there was no serious difference of opinion.
The question of the relation of the granulitic series to the serpentine
was complicated by the occurrence of veins and dykes of both acid
and basic rocks cutting serpentine and gabbro. He could not, in
all cases, separate these from the corresponding rocks of the granu-
litic series. He called attention to photographs and clay models
illustrating his theory that the granulitic rocks were of igneous
origin, and that many of the peculiar structures were the result
of deformation. The Author had accepted the igneous origin of the
granulitic rocks, and considered that the deformation took place
when the acid rock was intruded.

The main object of the joint paper by himself and Mr. Fox, so
far as it related to the section near Ogo-dour, was to call attention
to the interbanding of the serpentine and schist, and to the folding
which had affected the banded series. He thought that infolds had
sometimes been mistaken for intrusive tongues, and he pointed out
that transgressive junctions might be produced in connexion with
folding. He preferred the interpretation which he and Mr. Fox
had arrived at to that proposed by the Author.

Q.J.G.8. No. 205. E

50 , PROF. T. G. BONNEY ON THE [Feb. 1896,

Speaking as to the origin of hornblende-schists, he reaffirmed his
belief in the theory that both gabbros and basic dykes had been
converted into rocks of this character by dynamic metamorphism.
He pointed out that in 1887 he had called attention to the existence
of a zone of intense mechanical disturbance in the south-western
portion of the Lizard, and to the fact that this had been accepted by
the Author. The main mass of hornblende-schist lay to the east of
this zone: in the same position relative to a zone of disturbance as
the Moine Schists of Sutherland. There was a close resemblance in
structural features between the main mass of hornblende-schist and
the Moine Schist, and he thought it highly probable that this
resemblance would be found to be due to dynamic metamorphism.

The Rev. Epw1n Hitt said that Messrs. Fox and Teall seemed to
imply that granulite had been thrust into serpentine at the Lion
Rock, but it appeared to him that the opposite was the case. At
Potstone Point he saw no such folding as they seemed to speak of.
As for the fact that the bands of included masses of granulite
usually follow the external boundaries of the masses, it was most
natural to expect that the masses when ripped should yield along
the banding as lines of least resistance.

Gen. McManon said that, if he understood the Author aright,
the latter now believed that no part of the hornblende-schists had
originally been ash-beds; if so, he reserved his judgment on that
point. In all other respects he was in cordial agreement with the
Author. He had not visited the whole area covered by Messrs. Teall
and Fox’s paper alluded to, and could only speak to the parts of the
Lizard actually visited by him. He thought that there had been
granitic eruptions at different periods in the Lizard area, and that the
intrusion of the granite which had been injected into what is known
as the granulitic series was of earlier date than the granite which
had invaded the serpentine. As regards the question of the intrusion
of the serpentine into the schists, and the granulitic series, his mind
was at rest. He had seen several sections which had convinced him as
to the correctness of Prof. Bonney’s original discovery of the relations
of these rocks; and he mentioned, in particular, the section to be
seen in the Flagstaff Quarry, Cadgwith, which could not be explained
on the hypothesis of the serpentine being caught up in the folds of
the granulitic beds.

Sir ARcHTBALD GEIKIE sald that he had had the advantage of
being conducted over part of the Lizard district by Mr. Fox and
Mr. Teall, and though he would not venture to offer an opinion upon
most of the disputed questions in the geological structure of that
area, he had seen evidence sufficient to convince him that in the
Potstone Point part of the coast the serpentine and hornblende-
schist formed, as Mr. Teall maintained, a great complex which
presented a marked coincidence of banding and had been plicated by
one common series of movements. He could see no indication of
the serpentine being intrusive in the schists. Without expressing
any judgment as to their relative date or mode of origin, he could
not doubt that both groups of rock had been simultaneously exposed

Wels say 4 ROCKS OF THE LIZARD DISTRICT. ol

to the pressure which had resulted in the marked plication which
they both now exhibited.

Mr. J. H. Cottrys said that he had not visited the district referred
to by the Author for a dozen years or more, so that his recollection
of the facts upon which his opinion was based was rather hazy. He
had, of course, read the able papers which had been presented to the
Society by several eminent geologists in that period, but had not felt
ealled upon to alter in any important particulars the opinions which
he had expressed in 1885 in the ‘ Geological Magazine.’ It was
remarkable that so small an area should afford grounds for so great
a diversity of opinion : there were almost as many opinions as parties
of observers. There were, indeed, some indications of approximation
of divergent views; but the approximation was so small during
the eighteen years which had elapsed since the reading of Prof.
Bonney’s first paper, that he feared no one then present would live to
witness the general acceptance of the one and only right view which
would embrace all the facts.

The AvrHor said in reply to Mr. Teall that, from the remarks of
the latter, it appeared that he still adhered too much to the principle
which he (the speaker) thought likely to mislead—namely, restricting
the attention to single sections, and dwelling on the minor difficulties
presented by them, without regard to the evidence in other parts of
the district. Of this the speaker pointed out instances. He thought
that Mr. Teall had overstated the amount of banding visible in the
serpentines of the Mullion—Ogo-dour district ; as a rule (except in
the cases mentioned by the Author—what he considered to form a
mixture of the two rocks), it was only foliation. As for the
Norway peridotites, certain things had been asserted of them,
but not proved. Such bending as there was of the rocks about
Potstone Point could not be the result of flexure by ordinary
mechanical forces ; nor could this cause the ‘ flaser’ structure in the
gabbros of the east coast. In the former case the weld of the ser-
pentine and hornblende-schist would have been destroyed; in both
the serpentine would have been much broken, in the latter crushed,
for gabbro is one of the toughest of rocks. On this point his
experience in the Alps enabled him to speak with confidence.

E2

52 COL. H. W, FEILDEN ON KOLGUEV ISLAND. [Feb. 1896,

4, Norzs on the Guactan Grotoey of Arctic Kvropx and its Istanps.
Part I.: Kotevev Istanp. By Colonel H. W. Frrixpen, F.G.S8.
With an Apprnpix by Prof. T. G. Bonnzy, D.Sc., F.R.S. (Read
November 20th, 1895.)

Durine the month of July 1895, after two ineffectual attempts
to reach Novaya Zemlya, owing to the great accumulation of ice
in Barents Sea, we ran down the edge of the ice-pack, which ex-
tended intact from Novaya Zemlya to the northern end of the
island of Kolguev. We were fortunate enough to meet with a day
so fine and a sea so smooth that our party of five persons landed
without difficulty at the mouth of the Gobista River, on the south-
western side of Kolguey. Our yacht was sent back to Vardo for
coal, and we remained on Kolguev for ten days, encountering very
inclement weather. A most opportune break in an almost con-
_ tinuous series of gales and fogs enabled us to leave Kolguev on the
return of our vessel, without difficulty or danger.

The island of Kolguev lies in Barents Sea, distant some 50 miles
from the mainland of Arctic Russia, and about 130 miles south-
west from the nearest part of Novaya Zemlva. Its greatest breadth
is about 50 miles, and its extreme length 40 miles; the general
shape is oval. The superficial area may be roughly estimated at
2000 square miles. As a familiar comparison, we might liken it
in extent to our Kast Anglian county of Norfolk.

The soundings between Kolguey and the mainland of Europe do
not exceed 30 fathoms, while, in all probability, 70 fathoms is the
extreme depth between it and Novaya Zemlya. Kolguev, how-
ever, differs completely in geological structure from the mountainous
islands of Novaya Zemlya, and equally so from the ice-worn rock-
area of Russian Lapland, as throughout its entire extent no ex-
posure of basement-rock has been anywhere observed. It is wholly
and entirely a vast accumulation of glacio-marine beds.

Let us take a glance at the only geographical map of the island
of Kolguev we possess, namely that published by Mr. Trevor-Battye
in his valuable book.’ His stay on the island during 1894 was ten
times as long as mine in 1895, and his opportunities of travelling
about with the aid of the Samoyeds and their reindeer far
exceeded my rambles on foot. He traversed the greater part of the
island, while my experiences were confined to its western coast-
line. JI am pleased, however, to find that my observations agree
in the main with Mr. Trevor-Battye’s remarks on the geological
structure of Kolguev; and though I hope to add somewhat to our
information regarding the geology of this little-known island, his
valuable researches have greatly aided me in verifying my own.
Since my return to England I have had the further advantage of con-
sulting Mr. Trevor-Battye on certain points regarding the structure

1 «Tcebound on Kolguev,’ Constable & Co., London, 1895.

Vol. 52.] COL. H. W. FEILDEN ON KOLGUEV ISLAND. 53

of the higher lands of Kolguev; his information, note-book, and
sketches were generously placed at my disposal, so that I am able
to write with confidence on certain points which otherwise would
have partaken more or less of the nature of surmise.

As a general description of Kolguey, that given by Mr. Trevor-
Battye cannot be bettered in accuracy or terseness. He writes :—
«The superficial area of the island is sharply divisible into two
portions. Speaking generally, the northern two-thirds are high
ground, which consists of peat-covered or of bare ridges intersected
by gullies, and enclosing small lakes and swamps, and the re-
maining portion to the south is a dead flat of grass, bog, and peat-
levels reaching to the sea.’ He estimates the highest elevations of
Kolguev at 250 feet.

In the neighbourhood of the mouth of the Gobista River, where
we made our camp, and a mile inland, we found the highest spots
about 90 feet above sea-level; and when the atmosphere was clear
we could distinctly see the more elevated portion of the island,
Tising apparently some 10 or 15 miles to the eastward of our
station, Mount Sowandeyi and the remarkable, isolated, rounded
mass of Mount Bolvana being easily determined. The difference in
level between the summit of the clay-cliffs of the western coast
and the elevated plateau of the interior cannot be less than 200 feet,
consequently the elevated-plateau portion of the island must have
been the latest in deposition and the first part to emerge from the
sea. It is, therefore, a matter of satisfaction to me that I have
obtained from Mr. Trevor-Battye some fuller particulars regarding
the formation of Mount Sowandeyi, Mount Bolvana, and the highest
points that he visited in the northern plateau, than he has already
published (op. cit. pp. 392-395). At the highest point that he
traversed in the northern portion of the island, and not far from
the head-waters of the Pesanka, he found an elevation of 250 feet.
At this spot a good section showed from the surface about 80 feet of
sand-beds, charged with erratic boulders: these beds of sand rest
on clay. At Mount Sowandeyi, some 20 miles directly south, the
same formation shows again: the summit of Sowandeyi for a depth
of about 80 feet being composed of sand with boulders, imme-
diately underneath which comes the clay. Mount Bolvana, some
5 miles to the south-west, is similarly constructed.

From these observations of Mr. Trevor-Battye, made along a
line embracing the greater part of the high plateau of Kolguev,
‘we may reasonably infer that the entire elevated region of the
island is composed of beds of sand containing erratic boulders
to a depth of not less than 80 feet, and that these sandy beds rest
on the Kolguey Clays. Mount Sowandeyi and Mount Bolvana,
in my opinion, point toa great marine erosion which must have
taken place at the period of their emergence from the sea, for it is
hardly possible to doubt that they must have formed at one time a
continuous part of the northern plateau. The profile of Mount
Bolvana is very singular: it rises as a symmetrical cone above the

54 COL. H. W. FEILDEN ON KOLGUEV ISLAND. [Feb. 1896,

tundra, quite detached from the other hills to the northward, like
an islet in the sea.

The contour-shading of the elevated plateau in the map attached
to Mr. Trevor-Battye’s book is drawn rather too abruptly, and is
made to extend rather too much to the southward. From what I
saw, the elevated region does not extend south of Mount Bolvana,
but terminates with Mount Sowandeyi and Mount Lodka. When
the highland of Kolguev emerged from the sea, and the island was
then about two-thirds of its present size, in all probability Mount
Bolvana was its southern apex, and it is easy to understand, if
the elevatory process was slow, that the destruction of the soft
material of which it is composed might have been effected without
difficulty by marine erosion. I think this explanation satisfactorily
accounts for the present peculiar shape of Mount Bolvana, and that.
it was at one time an integral portion of the highland of Kolguev.

The appearance of the western side of Kolguev, though we coasted
along it in favourable weather and bright sunshine, is dismal and
uninteresting in the extreme. Low, dreary-looking bluffs of clay,
of a mournful bluish-grey colour and some 60 to 70 feet high,
stretch from the mouth of the Gosena River, at the north-western
end of the island, to the mouth of the Gobista; but there is a gentle
though perceptible lowering of the coast-line from north to south.
At the mouth of the Gobista River the height of the shore-bluffs.
has dwindled to about 40 feet. From the Gobista to the Kriva,
some 6 miles south, the land sinks more rapidly, and at the extreme
south-western corner of the island merges with the sea, a consider-
able portion of the island near the sea-shore being overlain with
recent sea-sand.

The margin of the bluffs that form the western shore of Kolguev
is not usually a vertical wall of clay, but is generally hidden under
a slope or talus which has fallen from above. The destruction of
the coast-line would be still more rapid, but for the protection given
by the snow-foot which forms upon the sloping talus. This snow-
foot is merely an immense accumulation which gathers in the ravines.
or collects upon the slopes. By the combined action of the sun’s
rays and the wash of the sea, this snow becomes of an ice-like
character, and gives effective aid in protecting the cliffs. Though
there are no rivers navigable by the smallest sea-going craft,
yet there are three streams of considerable size that discharge on
the western side of Kolguevy. These are the Gosena, Gobista, and.
Kriva rivers. I have visited only the last two. In addition there:
are many smaller rivulets that help to drain this supersaturated
island, and as they have cut out for themselves deep ravines, far
out of proportion to the volume of water that is carried off by them,
they give to the clay-cliffs a varied character, and in passing along
the coast we see ravine, and dell, and steep-sided watercourse, which
to a certain extent relieve the dreary monotony. ‘These minor
ravines, as a rule, are not of any great length. Originating as runnels
in the peat of the flat tundra, they act as drains for carrying off the

Vol. 52.] COL. H. W. FEILDEN ON KOLGUEV ISLAND. 55

melted snow and rain-water, but when they approach the shore-
bluffs their erosive powers are greatly increased. Not only is there
a wearing-out action, but there is an actual eating-back force, so that
in the last few hundred yards of their course the stream drops, say,
50 to 60 feet, and cuts out a broad ravine with very steep banks on
either side. It was in ravines of this nature that I obtained the
chief facilities for examining sections. We find that all these
streams in the last part of their course, and when almost on a level
with the beach, run over stones and boulders which have been
washed out of the surrounding mud-beds. An examination of these
stones, which are of every shape and form from angular fragments
to rounded and polished blocks, shows that a large proportion are
ice-scratched. The medley of rocks represented is remarkable,
granites and gneisses, limestones Silurian and Carboniferous, grits,
quartzites, porphyries, a variety indeed so great that it would take
a trained petrologist to enumerate them. Even the ordinary
observer cannot fail to perceive that an immense land-surface has
been put under contribution to supply such a diversity of rocks.
These boulders vary in size from that of a walnut to large di-
mensions. One that lay in a stream-bed a few miles north of the
Gobista River was a huge block of very hard yellow sandstone,
polished, scored, and striated. Along its major axis it had deep
flutings cut into it, and in addition it was transversely scratched.
It measured 15 feet in length, 9 feet in breadth, and 6 feet in
height. When we look around to the mud-and-clay cliffs we see here
and there stones and boulders of the same character as those that
strew the stream-bed sticking out of the banks, or resting on the talus
ready to slide down and join the others below ; we also observe that
these erratics do not exhibit the slightest tendency to form lines of
horizontal deposit in the beds. My opinion is that all have been
dropped from floating ice intermittently and tranquilly. The
matrix of clay around them shows no signs of disturbance; on
falling from the ice-rafts they have sunk gently into the yielding
mass, and now they lie throughout the beds looking like currants in
a cut loaf.

J have no altogether satisfactory explanation to advance for the
presence of such immense numbers of ice-scratched stones as occur
in these sedimentary beds of Kolguev. The action of an ice-
sheet cannot be invoked at Kolguev; yet, seeing that the ice-
scratched stones throughout the Kolguev Beds must in the aggre-
gate amount to millions, one naturally asks, where were they
manufactured? Undoubtedly stones frozen into the bottom of
floating ice become scratched and polished when stranded on shores
where there is sufficient rise and fall to admit of the ice-rafts
grating. Ihave seen this process of manufacture going on.’ It
is, however, diffieult to conceive a train of circumstances which
admitted of erratics being transported in floe-ice to some rocky

+ Quart, Journ. Geol. Soc. vol. xxxiv. (1878) p. 566.

56 COL. H. W. FEILDEN ON KOLGUEV ISLAND. [Feb. 1896,

coast, there to be scratched and then carried out to sea, and
‘deposited on the floor of the ocean. It seems more reasonable to
suppose that this great aggregation of ice-scratched erratics came
from glaciers, but the difficulty we have to face is, how do ice-scratched
stones get from the glacier to the ice-raft? That ice-scratched
stones do find their way into the subaqueous mud-moraines of
recent glaciers I can testify, but that is a subject upon which I
must not enlarge in this paper. If we admit that the Kolguev
erratics came from glaciers, where do we suppose those glaciers
to have existed during the period when the Kolguev Beds were
deposited ?

I should have brought away, had circumstances permitted, a larger
number of these erratics from the Kolguev Beds, but our landing
and embarcation had to be effected in great haste and in a row-
boat. I secured, however, several which I submitted to Prof.
Bonney, who has most kindly drawn up a valuable and exhaustive
report on the specimens, which appears as an Appendix to this

paper (p. 58).

The Kolguev Beds in the vicinity of the Gobista River may be
divided into clays and sands, but their differences of composition
merge into one another. Not infrequently the clays pass into
horizons of a more sandy composition, although so insensibly that
it is difficult to determine exactly where the change takes place.
The cliffs are so homogeneous in character, and the passage of the
clay-stratum into sand isso gradual, that the alteration is evidenced
more by the change of colour in the sections than by any definite
lines of demarcation. It is evident that no break has occurred in
the continuous deposition of these sedimentary beds. In general
colour, the Gobista beds remind me of our English Gault. No-
where did I notice layers of gravel traversing the beds, and in this
respect’ those of Kolguev differ from the glacio-marine beds of
Grinnell Land and Smith’s Sound. There the horizons of clay, sand,
and gravel are often distinctly defined. This arises from their
deposition close to land in shallow water. The Kolguev Beds were
evidently deposited in the sea, farther from shore than the Grinnell
Land beds, and every piece of rock larger than the constituent
particles of the beds themselves is, I am convinced, an ice-trans-
ported erratic.

The fossils included in the Kolguev Beds (I am not referring to
those which have been transported as erratics, but to the fossils con-
temporaneous with the beds themselves) are all mollusca, and well-
known boreal forms, existing at the present time. Though in
various sections fragments of Saaicava arctica, Mya, etc., appeared
to be dispersed from top to bottom, yet they were certainly rare, and
I obtained but few entire examples. Very likely I was unfortunate
in the localities that I investigated ; moreover, my stay on the
island was brief, and I had necessarily many other duties to occupy
my time besides searching for fossils. Still, I submit that these
molluscan remains, found in various localities and through the whole

~

Wort 52] COL. H. W. FEILDEN ON KOLGUEV ISLAND. 57

exposed thickness of some of the beds, all of which are (in my
opinion) sedimentary, afford proof of their marine origin.

Mr. Edgar Smith has been good enough to carefully examine and
name the specimens which I collected, with the following result :—
Natica affinis (Gmelin) or N. groenlandica, Beck; fragments of
gasteropod (Stpho?sp.); Saxwava arctica (Linn.); Astarte com-

essa (Montagu); Astarte borealis (Chemn.); Mya arenaria, Linn. ;
fragments of Mya, sp.

I am unable to advance any satisfactory theory, either for the
paucity of the molluscan remains in the Kolguev Beds, or for the
greater part of what I found being fragmentary. I was un-
successful in finding the remains of any marine vertebrate and
equally so in discovering drift-wood in the beds; the latter, it
will be remembered, is pend aut in the glacio- marine deposits of
Grinnell Land.

It may be interesting to compare, and contrast if need be, the
Kolguev boulder-clays with the deposits which bear the same name
in England and Scotland. To a certain extent all those that we have
at home are fragmentary when compared with the boulder-bearing
‘beds of Kolguev, which we may safely assume are 50 miles in
length by 40 in width, with a thickness of not less than 250
‘feet, probably far more, all lying in one undisturbed mass, without
the slightest sign of a basement or interrupting rock. Moreover, I
met with no deposit in Kolguev precisely similar to what is called
‘till’ in Scotland. I mean by ‘till’ a firm, tough, tenacious,
strong clay; in the words of Prof. James Geikie, ‘so tough indeed
does it often become that engineers would much rather excavate
the most obdurate rocks. ... But till has neither crack nor joint—it
will not blast, and to pick it to pieces is a very slow and laborious
process.’”* On the other hand, there are many deposits in Britain
called ‘ Boulder Clays’ which are in no degree superior in toughness
to those of Kolguev, for instance those of the Yorkshire coast ; the
Chalky Boulder Clays of Norfolk may be also cited as another
example. I am inclined to think that the tenacity or the reverse
of Boulder Clays depends greatly on the nature of the rocks from
which they have been derived. By these remarks I do not wish
to imply the impossibility of Till or Boulder Clay being formed as a
moraine profonde under an ice-sheet; I merely suggest that many
Boulder Clays in this country and in other parts of the world may
have been deposited under water, and that the transport of their
included ice-scratched stones may be due to floating ice. It is sugges-
tive that all the glacial deposits which I have met with in Arctic and
Polar lands, with the exception of terminal moraines now forming
above sea-level, in areas so widely separated as Smith’s Sound,
Grinnell Land, Northern Greenland, Spitzbergen, Novaya Zemlya,
and Arctic Norway, should be glacio-marine beds. Throughout this
broad expanse of the Arctic regions I have come across no beds
that could be satisfactorily assigned to the direct action of land-

1 James Geikie, ‘Great Ice Age,’ p. 10, London, 1874.

58 PROF. T. G. BONNEY ON THE ERRATIC [Feb. 1896,

ice: that is to say, beds formed in setu by the grinding force
and pressure of an ice-sheet. On the contrary, so far as I can judge,
the glacial beds which I have traced over the extensive area
mentioned above have all been deposited subaqueously and re-
elevated.

Nowhere have these facts been more strikingly confirmed than by
the investigation of the geological structure of Kolguey. There we
find a large island emerging from Barents Sea, showing to my mind
evidence, by its sedimentary glacio-marine beds, of the absence of an
ice-sheet from the area when these beds were deposited, and its:
formation under conditions similar to those which at present exist.
in Barents Sea.

APPENDIX.

Report on the Exraric Bounpers from the Kotevev Bens.
By Prof. T. G. Bonnry, D.Sc., LL.D., F.R.S.

(1)? A granitoid rock, with reddish felspar, which, under the micro-
scope, is found to consist of grains, rather fragmental in
aspect, of quartz and felspar, and of clustered flakes of biotite.
These are cemented by a mosaic, partly of smaller quartz-
grains, occurring in patches, which at times also suggest that
they may possibly be fragmental, partly of quartz and felspar.
These smaller quartz-grains contain a large number of hair-like
microliths. The felspar, where distinguishable, is either ortho-
clase, plagioclase, or (rarely) microcline. The larger grains
contain enclosures of quartz or felspar, or a flake or two of
biotite. One or two of the smaller crystals are fairly idiomor-
phic, but as arule their outline is rather irregular, and they
are sometimes bordered by a micropegmatitic zone, of irregular
form, which seems to invade the mineral as though it had been
the result of a corrosive process acting from without. The
biotite occurs in rather small, irregularly-shaped flakes, of
which the larger sometimes contain granules of quartz or
felspar. These flakes are clustered in a way that suggests the
possibility of their representing an original flake of larger size,
which has been broken up and subsequently in part recon-
structed. There is a little apatite and zircon. I think that
the rock has been subjected to a certain amount of mechanical
disturbance, which has been followed by reconsolidation. So
far as I can form any opinion as to its age, I should judge it
to be Archean.

(11) A gneissic rock, not strongly banded, consisting chiefly of
quartz, a pale reddish felspar, and a dark hornblende. It is
very like an Archean gneiss, such as some of those occurring
in Canada, Greenland, ete.

(13) A rock with a darkish microcrystalline groundmass in which
are roundish felspar-crystals, up to about 3 inch in diameter.

1 The numbers within parentheses are those placed by Col. Feilden on the
specimens.

Vol. 52.] BOULDERS FROM THE KOLGUEV BEDS. 59

Under the microscope it is found to consist of an almost micro-
crystalline groundmass, in which are scattered larger crystalline
grains. This groundmass is composed mainly of quartz and
felspar, exhibiting occasionally an approach to a pegmatitic
structure, but generally forming a rather irregular mosaic, as if
the two minerals had simultaneously crystallized. Interspersed
with these, with a rather ‘clustered’ habit, are numerous
needles, apparently of a darkish actinolite, and occasional
flakelets of biotite. The larger (porphyritic) crystals are both
quartz and felspar ; the former mineral is not abundant, but it
occasionally includes a small grain of felspar or flake of biotite,
is sometimes corroded by the groundmass, and is often cracked.
The latter mineral, however, exhibits a structure which is not

-a@ common one. It contains numerous enclosed grains, often
rather rectangular in outline, of another felspar, and sometimes
of quartz, like a ‘lustre-mottling.’ These enclosures occur
somewhat sporadically, 2. ¢. they occupy only a part of a crystal.
This also, in one or two cases, has evidently increased in size
during the last stage of consolidation. We have found, for
instance, two planes (perhaps a basal and a clinodome) outlined
by minute flakes of biotite, and marking a change in structure,
though not in optical continuity. The outer zone, about +, inch
in maximum breadth, contains a larger number of quartz-
enclosures, and these are ranged as if they had grown from the
original surface of the crystal, somewhat as the crystals in a
granite occasionally group themselves at a junction with

another rock. This particular crystal also shows an approach
to a micropegmatitic structure, which, however, sometimes
passes beyond the boundary. These larger felspars, as a rule,
do not exhibit the oscillatory twinning of plagioclase; one or
two are orthoclase, twinned on the Carlsbad type, a few pro-
bably are microcline. One or two small zircons are present.
The rock would be called by some a quartz-felsite or quartz-
porphyry, by others a microgranulite. The general structure
(except for the peculiarities of the felspar) resembles that of
the rock figured by Fouqué and Lévy, ‘ Minéralogie Micro-
graphique,’ pl. x. fig. 1).

(21) A darkish, purple-spotted grit, which, under the microscope,
proves to be composed of fragments, subangular to fairly
rounded, of minerals and rocks. Among the former are quartz
and felspar, which in one or two cases are associated as if they
came from a holocrystalline rock. Among the latter are many
fragments of volcanic rocks. These are now devitrified and
often rather decomposed, but they evidently were once in a
glassy or slaggy condition. Occasionally they are blackened
with opacite ; felspar-microliths are present in some. Appa-
rently they represent some of the less acid trachytes—probably
andesites ; possibly, in one or two cases, even basalts. These
exhibit considerable variety, so that they hardly can have come
from a single volcano, but nothing worthy of detailed descrip-

60 PROF. T. G. BONNEY ON THE ERRATIC [Feb. 1896,

tion. A fragment or two of a volcanic grit is also found, and
the groundmass contains a little of a carbonate. The rock re-
sembles some of the volcanic grits, which in Britain occur just
below (or, as others would say, at) the base of the Cambrian
system.

(2) A rock, apparently similar to the last, but containing two or
three pebbles up to 2 inch in diameter. Two are probably a
reddish quartz, a third is green in colour, with colour-zoning,
possibly a fine-grained quartzite.

ey A fine-grained blackish grit, with several little flakes of mica.
Under the microscope it is found to be composed of angular
fragments of quartz, felspar, and a mudstone or phyllite, with
some flakes of white mica, and, more rarely, of biotite. The
felspar is often rather decomposed, and full of tiny flakelets of
colourless mica, but plagioclase can be recognized. There is a
good deal of a brown staining, some of which may be a hydro-
carbon ; possibly also a trace of a cleavage making a high
angle with the bedding. I cannot say more than that I should
conjecture the rock from its general appearance to be Paleozoic.

A rough vein-specimen, quartz and calcite, apparently from a ‘ dark
slaty rock.’

(16) A very pale cream-coloured subcrystalline limestone. Under
the microscope it is seen to be slightly dolomitic, and composed
of irregularly-shaped grains, differing considerably in size.
Evidently it once contained rather numerous organisms, but
these are too much altered for exact identification. I recognize,
however, traces of fragments of lamellibranchs, perhaps one
or two small gasteropods, and several foraminifera, not impro-
bably representing Globigerina, Orbulina, and a Rotaline form.
I think the rock very likely to be Mesozoic in age. It re-
sembles some of the purer limestones in the Alps, where they
have had a sharp ‘nip’ between the crystallines, and I believe
that it has been affected by earth-movements, followed by
reconsolidation.

(6) A piece of purplish-red chert. Under the microscope clear
spots or veins appear in a brown-speckled ground. On ap-
plying the nicols, the clear constituent throughout the slide is
found to be chalcedonic quartz, which here and there in the
untinted part (where the granules run larger) shows an approach
to a spherulitic structure. The tinting material may be called
ferrite, but while some of the larger grains can be recognized
as brown iron-oxide, others are pyrite. In this part of the slide
small cylindrical bodies can be frequently identified, which,
though badly preserved, I believe to be sponge-spicules, and
there are possibly indications of other organisms. The rock
undoubtedly is a chert, but I cannot determine its age.

(17) *Half of a rather large dome-shaped Favosites gothlandica

* As I was anxious that the identification of the fossils should rest on better
authority than mine, I submitted the specimens marked with an asterisk to
E. T. Newton, Esq., F.R.S., who has kindly named and commented on them.—
iG. B.

Vol. 52.] BOULDERS FROM THE KOLGUEV BEDS. 61

(syn. F. Goldfussi). As this species ranges from the Silurian
into the Devonian, the age is uncertain.

(3) *A darkish fossiliferous limestone. ‘The greater part of this is
made up of Amphipora (Caunopora) ramosa, a Stromatoporid
peculiarly Devonian ;’ with it a coral, which may be a Dibuno-
phyllum, and probably a piece of Monticulipora.

(14) * Piece of grey limestone containing Diphyphyllum.

* Hight smallish specimens, very full of fragmental organic remains,
seemingly to some extent etched out by action of water. One
specimen, measuring about 2 inches by 14 inch, contains the
spiral arm of a brachiopod (? Spzrzfera), a crinoid stem, and
piece of a lamellibranch. In one of the others we find Polypora,
with fragments, large and small, of Monticuliporids. Similar

organisms occur in the rest, one possibly containing Fenestella,
‘if it be not Polypora. May be Carboniferous in age, possibly
older.

(22) * A fragment, about 13 inch long and not quite ?inch wide at
the narrower end, of a belemnite, with an excentric alveolus,
extending to within 1 inch of the bottom. [This has since
been determined by Mr. G. C. Crick as almost certainly
Belemnites subquadratus, a species recorded from the Upper
Portlandian of the coast opposite Kolguev Island. ]

The specimens of an olive-grey fine-grained sandy mudstone, with
plant-remains, and of lignite, were submitted to A. C. Seward, Esq.,
M.A., F.G.S., who has kindly furnished the following notes :—

*(12) In this specimen, a microscopical examination of the surface
reveals the existence of a structure which is probably that of
imperfectly silicified coniferous wood. The cavities of the
trachez appear to have been filled with silica, and present the
appearance of delicate and regularly-arranged rods; here and
there the series of longitudinally-running rods are crossed by
others at right angles, suggesting medullary rays seen in
radial view. J am unable to make out any character which
will enable me to pronounce a definite opinion as to the geo-
logical age of the rock.

(4) Preservation similar to that in specimen No. 12. Impressions
of coniferous wood. ‘The irregularly pitted portions are also,
I believe, weathered pieces of wood ; a very similar appearance
is presented by undoubted specimens of coniferous wood in my

_- possession.

(5) Fragments of coniferous wood.

(17) Fragments of carbonized coniferous wood. Sections of a
small piece of this wood show fairly well the tracheids and
medullary-ray cells characteristic of the Conifer, but the
preservation is not sufficiently good to enable one to offer an
opinion as to the precise nature of the plant.

Ingnite (A).—A piece of coniferous wood with distinct annual
rings. There appear to be large resin-ducts traversing the
spring wood longitudinally. Possibly a more complete exami-

62 PROF. T. G. BONNEY ON THE ERRATIC (Feb. 1896,

nation of thin sections may lead to a generic or even a specific
determination.

Ingnite (B).—A naked-eye examination of this smaller piece of
lignite brings out the features of coniferous wood. The annual
rings are fairly well marked. In thin slices the tracheids and
medullary rays are clearly seen, but the preservation is not
sufficiently good for one to recognize the manner of occurrence
of the bordered pits. In one slide there are a number of fungal
hyphe distinctly preserved, running irregularly through the
woody tissues.

The general impression arrived at from an examination of the
specimens is that the rocks are probably Mesozoic in age, and either
Jurassic or Wealden. But, without further evidence, it would be
rash to offer a more definite opinion as to the geological horizon.’

Ice-worn Stones.

These are all striated, and in form resemble the ice-worn specimens
from a till or boulder-clay. Though I have not used an acid, and
scarcely employed the knife, I think the following determinations
are correct.

(2) A fine-grained dark grit, probably identical with (19).

(9) A slate-grey limestone, apparently a piece of Carboniferous —
Limestone.

(18) A dark grey limestone, Carboniferous, or possibly Devonian,
not unlike the matrix of (3).

(15) An almost black compact limestone (? traces of small organisms);
very like some of the darker Carboniferous Limestone of
Britain.

(10) A heavy compact brown rock, probably a piece of ironstone
(? Carboniferous).

In addition to the above-mentioned specimens are five glass —
tubes, containing samples of the glacial deposits, described by
Col. Feilden; in four cases clay, in the other sand. Small portions
of each have been studied under the microscope. In those from the
clay [have identified the following minerals:—Fairly common: quartz
and felspar (plagioclase and microcline recognized); much more
sparingly, a colourless mica, hornblende and augite—both green-
coloured, garnet, zircon, iron oxides, and rounded grains of glau-
conite, some certainly the casts of foraminifera.

The tube marked A was filled with lumps of a rather hard, dark,
brownish-grey clay, and in the preparations from it I also found a
sponge-spicule. B contained a mixture of a more earthy deposit,
nearly the same colour as the clay, with a little grey sand. Here I
identified the speckled filmy substance frequently seen in muds
and the colourless mica was more abundant. There wasalsoa little
biotite and one or two sponge-spicules. © contained a material
like A, but a little darker in colour and not quite so coherent.
Here too was the filmy substance, as before; also chlorite or a
greenish biotite, a sponge-spicule, and one possibly belonging to

Vol. 52.] BOULDERS FROM THE KOLGUEYV BEDS. 63

some other organism. JD contained a rather light grey silty clay ;
fragments of garnet were rather commoner in this, and one or two
rounded prisms of a slightly ferruginous rutile. E contained a fine-
grained quartzose sand. This proved to be wholly composed of
mineral fragments, mainly quartz; possibly a few chips were from
flint. Garnet, colourless mica, glauconite, iron oxide, and sponge- |
spicules were fairly common. Im all these samples the fragments
are mostly angular or subangular, a rounded grain, which some-
times is rather larger in size than the rest, only occasionally being
found. The materials bear a genera] resemblance to those forming
the Glacial drift of East Anglia.

Discussion.

Mr. Marr asked the Author whether there was distinct strati-
fication of the Kolguev Clays. The glacio-marine clays at the end
of the Malaspina glacier, and those upraised in the Chaix Hills
through that glacier, were well stratified and contained well-
preserved shells, as described by I. C. Russel. He called attention
to a paper by Torell (‘ Sveriges Geologiska Undersokning,’ 1878),
in which the termination of the Scandinavian ice-sheet was carried
to Tcheskaya Bay. If it were continued north in the same direction,
' the ice passing over Lapland, the White Sea, and the Kaninskaia

Peninsula might carry eastward Archean, Devonian, and Car-
boniferous fragments, such as were stated by Prof. Bonney to occur
in the Kolguev Clays.

Mr. Trevor-BartyEe remarked that he was naturally very glad to
find that Col. Feilden’s recent observations supported the views
which he had himself expressed in the Geological Appendix to his
lately published work, ‘ Ice-bound on Kolgueyv.’ Actual obser-

yation on the spot was worth much theory at a distance; and he
ventured to believe that no one in that room, if he had had similar
opportunities of investigating the Kolguev deposits—the absence of
any continuity of rock in situ, the astonishing variety of ice-scratched
erratics, the composition and relations of sand and clay, the indefinite
lines of strata between these, the presence of immense isolated
spherical and striated boulders, and the presence of mollusca—could
hesitate to believe that these all had been dropped from floating ice,
or that the symmetrically conical shape of those isolated hills which he
had described in his book was due to later erosion by the sea. The
secondary elevation of the island above the waves was interestingly
emphasized by (i) the absence from the island of the Arctic hare and
the lemming; by (ii) the absence of Saxifraga oppositifolia, Mertensia
maritima—animals and plants of wide Arctic distribution; and,
further, by the absence of Ledum palustre, a striking feature of the
opposite mainland.

Mr. Bovuxerr pointed out the contrast offered by the deposits on
the islands of Solovetsk and Anzersk to those described by the Author
in that in the former islands there is nothing but a granitoid gneiss,
apparently of Scandinavian origin, in boulders embedded, with some

64 COL. H. We FEILDEN ON KOLGUEV ISLAND. [Feb. 1896,

signs of stratification, in sand of the same composition. If, then,
the Kolguev rocks are derived from the Kanin Peninsula, they do
not seem to come from the south of east. The raised beaches of
Anzersk confirm the indications of recent elevation afforded by
Kolguev.

Dr. G. J. Hivpe considered that the distinctly striated boulders
and the other specimens brought by the Author from Kolguey, indi-
cated that the clays in which they were embedded were of the
nature of genuine boulder clay (with which, indeed, the Author
had compared them) formed beneath a glacier. It did not seem
possible that such an enormous amount of ice-marked material
should have been deposited from floating ice. The presence of
Arctic mollusca in the clays would not invalidate this conclusion, for
similar shells occurred in deposits generally recognized as Till or
Boulder Clay.

Dr. Greeory said that all geologists would welcome the Author’s
return to the subject of Arctic geology, to which he had already
made most important contributions. He thought it necessary, in
order to interpret the geology of Kolguev, to consider it in relation
to the general problems of North Russian glacial geology. It was
generally agreed that there were two centres of glaciation in that
region—the Scandinavian, which spread eastward over the Kola
Peninsula, and the Tomain-Ural, which flowed westward. These
broke up into local glacial centres, and then followed a marine trans-
gression from the north. Russian geologists now attached less
importance to sea-borne ice than they formerly did. The erratics
described by Prof. Bonney seemed to show that the Kolguev area
was within the range of the Scandinavian ice. He referred to
several points in Col. Feilden’s description, which suggested doubts
as to whether Kolguev is wholly composed of marine glacial beds,
and to the paper by Tchernychev and Nikitin on the glacial geology
and erratics of the adjacent Kanin Peninsula.

The Rey. Epwin Hitt noted the novelty of ice as a protective agent.
The East Anglian clays in area and thickness are comparable to
those of Kolguev, and not unlike the Author’s descriptions ; their
stones are scratched just as those shown. He asked what were the
criteria by which the beds were proved to be marine, for it seemed
hard to find any criteria generally admitted by advocates of land-ice.
He called attention to the greater value of erratics whose home was
near for determining the direction of transport.

The AurHor begged to thank the Fellows for the favourable re-
ception of his paper. He was still more obliged for the useful
criticisms of Mr. Marr, Dr. Gregory, Dr. Hinde, and the Rev. E.
Hill, as in replying to them he could clinch his arguments.
Mr. Marr evidently hesitated to accept the Author’s determination
that Kolguev Island was made up of a vast series of marine beds,
laid down without the visible extrusion of a basement-rock, and
quoted Prof. Torell’s views on the extension of the Scandinavian
ice-cap, so as to include the Kanin Peninsula. But this in no way
affected the Author’s determinations of the Kolguev Beds, for Torell

Vol. 52. ] COL. H. W. FEILDEN ON KOLGUEV ISLAND. 65

never visited Kolguev, nor, as far as he was aware, ever propounded
any opinion as to the formation of Kolguev, nor as to an extension of
the Scandinavian ice-sheet over Barents Sea; consequently Torell’s
views and those of the Author did not come into conflict. Dr.
Gregory and Dr. Hinde apparently thought that the product of an
ice-sheet ought to be where the marine beds of Kolguev now are,
and questioned the correctness of the Author’s determination of the
Kolguev Beds. He could assure the Fellows that the Kolgueyv
Beds are as certainly sedimentary beds as the Thanet Sands, or the
Thalassic ooze of Barbados. In reply to the Rev. E. Hill, he ad-
mitted that he ought, when comparing the extent of the Boulder
Clay deposits of England and the glacio-marine beds of Kolguev, to
have made it clearer that the comparison was with areas of continuous
Boulder Clay without any exposure of a base-rock.

Prof. Bonney disputed the statement that the ice-scratched stones
from Kolguev resembled those of moraines, and said it was an
assumption that the glacial beds of Kast Anglia were the product
of land-ice. It was not yet proved that shell-bearing beds were
or could be produced by land-ice, and we ought to explain British
deposits by those of Arctic regions rather than to follow the reverse
process.

Q.J.G.8. No. 205. F

66 MR. F. RUTLEY ON THE ALTERATION OF _—[ Feb. 1896,

5. On the Atreration of certain Basic EruptiveE Rocks from
Brent Tor, Devon. By Franx Rorzy, Esq., F.G.S. (Read
December 4th, 1895.)

[ Abstract. ]

Two microscopic sections of rocks occurring on the north side of
Brent Tor were examined, and a cursory glance suggested at once the
idea that they might originally have consisted to a greater or less
extent of extremely vesicular basalt-glass. No unaltered vitreous
matter, except perhaps mere traces, can now be detected in these
specimens, the interest of which lies in the assemblage of alteration-
products which they contain. A third section cut from a small chip
collected at the southern side of the base of the Tor consists of a highly
vesicular lava of a hyalopilitic character, which may be regarded as
an amygdaloidal glassy basalt.

The Author gives a detailed account of the microscopic characters
of the three sections, and discusses the history of the rocks, com-
paring them with Tertiary basic glass, and with the Devonian
rocks of Cant Hill, which he described previously. He brings
forward evidence in favour of the view that the original alteration
of both the Brent Tor and Cant Hill rocks was palagonitic, and
that while in the Brent Tor rocks the subsequent alteration of the
palagonite into felsitic matter, magnetite, secondary felspar, epidote,
and probably kaolin, and some serpentine and chlorite was com-
plete, it was only partial in the case of the Cant Hill rocks. We
may therefore assume that palagonite is not the ultimate phase of
alteration in basic igneous rocks.

Discussion.

Gen. McManon enquired whether the Author had worked out in
detail the chemical changes involved in the conversion of palagonite
into ‘ felsitic matter’ and ‘ secondary felspar.’ He understood the
Author to state, and the illustrations exhibited seemed to imply, that
palagonite was changed in situ into ‘ felsitic matter’ without the
addition of any extraneous material ; but as the chemical composition
of palagonite, as seen in the table on the wall, only showed a total of
8-60 per cent. of aluminium oxide, some explanation as to how this
change could be brought about seemed necessary.

Prof. Bonney said that he thought most of the Author’s con-
clusions would not be disputed, for the changes which had been
described had many precedents, though he doubted whether it was
possible to trace the mineral alteration of palagonite until it was
more precisely defined what is Balegpmite. But he agreed with
Gen. McMahon in thinking that ‘felsitic matter’ could not be
formed from an ordinary palagonite, unless we assumed chemical
changes which were not probable.

Vol 52.1 BASIC ROCKS FROM BRENT TOR. 67

Mr. W. W. Warts enquired for further particulars concerning the
rock which contained what might possibly be pseudomorphs after
leucite. He was interested in this rock, because he had discovered
a phonolite with some affinities to that of the Wolf Rock at Black-
‘ball Head in Cork. He also asked whether the age of the Brent
Tor rocks was definitely known, as the Irish rocks referred to were
clearly post-Carboniferous and yet had no affinities with the products
of Permian voleanos. Were there any Tertiary volcanic rocks in
Devon ?

Col. Burton-Brown would like the Author to express an opinion
of the probable temperature under which these interesting changes
in the palagonite were supposed to be taking place.

Dr. Hicxs said that some years ago he visited Brent Tor and
examined some of the surrounding rocks, and he wished to ask the
Author whether he considered the volcanic rocks as of Lower
Carboniferous or as of post-Carboniferous age.

Prof. Hutt also spoke.

The AvrHor, in replying to Gen. McMahon’s question, stated that
basalt-tuffs were very variable in constitution, and in some cases
conversion into palagonite might only be partial. One analysis of
basalt-glass from Kilauea gave nearly 14 per cent. of alumina. He
thanked Prof. Bonney for the kind terms in which he had spoken
of the paper, and in reply to his criticism concerning the presence
of felsitic matter in the tuffs and lavas of Cant Hill, he pointed
out that the amount was comparatively small, and that reserve
was entertained about it in the paper, since some of the micro-
crystalline matter might be chalcedonic. In answer to Mr. Watts,
he stated his belief that the approximately circular sections in some
of the Cant Hill rocks were infilled vesicles, although they certainly
did bear a general resemblance to the rounded crystals in the
leucitites of Monte Albano and of the Capo di Bove, as indicated in
the drawings to which Mr. Watts referred. The question of
Dr. Hicks with reference to the precise age of the eruptive rocks of
Brent Tor was difficult to answer, since the boundary between the
Devonian rocks and the Culm was considered very doubtful by Sir
Henry De la Beche and had not yet been definitely settled. It was
a question for paleontologists to decide. He thought that these
eruptive rocks were of Carboniferous age at latest.

F2

68 MR, H. WOODS ON THE MOLLUSCA [Feb. 1896,

6. The Motusca of the CHatk Rock: PartI. By Henry Woops,
M.A., F.G.S. (Read December 4th, 1895.)

| Puates IT.-IV.]

CoNnTENTS.
Page
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Ty Odphalopodas 3.2.2 ...0..00..c0ccseeccseeeseecesreceesnreserscasa sannmasoeecsen 73
Nautilus. Prionocyclus.
Ptychoceras. ~ Pachydiseus.
Hamites. Scaphites.
Heteroceras. Crioceras.
Baculites.
AME GARECKO POUR) vocee eda -ce sees oecceseesencasssnseres-ssnaeneuneeceense steam 85
Emarginula. Natica.
Pleurotomaria. Cerithium.
Trochus. Aporrhais.
Turbo. Lampusia?
Crepidula. Avellana.
TY, Scaphopoda .............0000-00 us in Suaieniganiides ands ats\cechs eanehe eee 96:
Dentalium.
Mie Pa DIGS OF MDIGLT IDUGION .ciccccsnsqccesarensccceaactccndsgenseacanaetteneeee 94, 95

I. Intrropuction AND LITERATURE.

Tue Chalk Rock is a bed of hard, usually cream-coloured limestone,
occurring at the top of the Middle Chalk ; it succeeds the zone of
Holaster planus and is followed by the zone of Micraster cor-testudt-
narium. Noticeable features in the bed are the presence of grains:
of glauconite and numerous green-coated nodules of phosphatic
chalk. Under the microscope it is characterized by the abundance
of foraminifera, especially Globigerina, and by numerous fragments.
of the tests of mollusks and echinoids ; the bright green grains of
glauconite are also conspicuous. The insoluble residue, obtained by
treating with hydrochloric acid, was found by Dr. W. F. Hume to
consist mainly of quartz and glauconite; augite, hornblende, and
tourmaline occur very rarely. Frequently the Chalk Rock is not:
hard throughout, but contains irregular cavities filled with soft
mealy chalk or with red sandy clay. Analyses of the rock have
been made by M. Duvillier,’ Dr. Frankland,* Mr. C. W. Meanwell:
and Mr. P. G. Sandford,* and they show from -20 to :718 per cent.

1 In this paper I have adopted the zones given by Mr, Jukes-Browne in:
Whitaker’s ‘Geology of London’ etc., vol. i. (1889) p. 58 (Mem. Geol.
Survey).

a an ‘Description géologique de la Craie de l’Ile de Wight,’ Ann..
Sciences Géol. vol. vi. (1875) p. 19.

8 Penning and Jukes-Browne, ‘Geol. of the Neighbourhood of Cambridge,.
Mem. Geol. Surv. (1881) p. 66.

4 ‘Handbook of the London Geol. Field Class’ (1892), pp. 120, 121.

Vol. 52.] OF THE CHALK ROCK, 69

of phosphoric acid—a large amount compared with that usually
found in chalk.

The best development of the Chalk Rock occurs in Berkshire,
Oxfordshire, Buckinghamshire, and Bedfordshire; its average thick-
ness is about 3 feet. In the Isle of Wight it varies from 8 inches
to 2 feet 7 inches. In Dorset and Devon it consists of a layer of
green-coated nodules only. Near Winchester (at Twyford) the zone
ean be traced by means of the characteristic fossils, but the rock is not
hard and does not contain nodules. South-south-west of Marlborough
the thickness, according to Mr. Whitaker, is 12 feet. Near Cuck-
hamsley, on the Berkshire Downs, there are several good exposures
of the Chalk Rock, showing a thickness of from 7 to 10 feet, which
have yielded numerous fossils. The thickness of the bed at Harts
Old Lock (north-west of Pangbourn) is 6 feet, at Aston Rowtant
A feet, and in Buckinghamshire it varies from 4 feet at Medmenham
to 9 feet 10 inches at Prince’s Risborough. At Aston Rowtant (and
:apparently throughout Buckinghamshire and Bedfordshire) there is,
at about 20 feet above the Chalk Rock, and separated from it by
halk containing many Micrasters, another bed of hard limestone,
somewhat similar to the Chalk Rock, but not so thick, and contain-
‘ing fewer fossils. In the cutting on the Midland Railway south of
Zuton there is an excellent section showing the Chalk Rock and the
shard bed above it. The former has a thickness of 2 feet, and is
separated from the higher bed by 10 feet of soft chalk. There is a
good exposure in a quarry near the station at Boxmoor (Herts)
where the rock has a thickness of 14 feet; numerous other sections
‘in Hertfordshire occur in the neighbourhood of Hitchin, Baldock,
ete. In Cambridgeshire it is seen south of Abington, having a
thickness of from 2 to 5 feet, north-west of Westley Waterless 2 to
3 feet thick, and also near Stetchworth. The Chalk Rock is not
exposed in Suffolk, and in Norfolk there is one section only, namely,
on the railway-cutting west of Little Friars Thorn, where its thick-
ness is 1 foot. Around the Weald the Chalk Rock has been recog-
mized at various places: at Dover it was identified by Mr. W. Hill;
near Beachy Head and Lewes it is also present, according to
Dr. Barrois; while on the northern side of the Weald it is seen at
Guildford, Burham, and elsewhere. In the deep boring at Richmond
the Chalk Rock, 5 feet thick, was met with at a depth of 553 feet
from the surface. In Lincolnshire and Yorkshire the bed has not
‘been found.

The most striking and interesting feature of the Chalk Rock is
its paleontology ; in the first place, fossils are very much more
abundant in it than in the overlying and underlying beds, and,
secondly, the general facies of the fauna is peculiar, owing to the
presence of genera and species not found in the other zones of the
Upper and Middle Chalk, and also to the abundance of certain
groups, especially the cephalopoda and gasteropoda, which are com-
‘paratively rare in the beds just above and below. As a whole, the
fauna presents a much greater resemblance to that of the Lower

70 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

Cenomanian than to any which occur in the divisions of the
Senonian and Turonian above and below it; and whereas the latter’
are of a deep-water type, that found in the Chalk Rock is certainly
of a comparatively shallow-water character.

The first mention of the Chalk Rock was made by Mr. D. Sharpe:
in his monograph on the ‘ Mollusca found in the Chalk of England”
(1855, p. 52), where he speaks of it as a ‘ bed of rather hard chalk,.
which occurs near the bottom of the Chalk with Flints, and contains
A. peramplus, Scaphites, and several other species of Mollusca.
hitherto undescribed, and only known in this bed.’ But the Chalk
Rock was first noticed under that name in the ‘ Catalogue of the
Rock-specimens in the Museum of Practical Geology’ published in
1860. A little later a much fuller description appeared in the
‘ Quarterly Journal’ by Mr. Whitaker, who recognized its occurrence
in Wiltshire, Berkshire, Buckinghamshire, and Hertfordshire. This:
author, however, regarded it as occurring between the Upper and
Lower Chalk ; later writers have taken it to be either the upper-
most bed of the Middle Chalk or the lowest of the Upper Chalk.

The Chalk Rock fauna has been recognized at various localities:
on the Continent. In France it occurs in the Angoumien division.
In North-western Germany (Westphalia, etc.) the bed is represented
by the zone of Heteroceras Reussianwm; and in Saxony by the:
Scaphites-beds, and by part of the Inoceramus Brongniarti-beds.
(Pliner-Kalk). In Silesia the Kalk-Mergel of Oppeln belongs to
this zone, as do the Teplitz Beds in Bohemia, or at any rate part of
them. Lastly, in Bavaria the Pulverthurm Beds (the middle division:
of the Kagerhoh Beds) are on the same horizon.

On account of the wide distribution of this fauna, and its contrast:
with that found in the adjacent zones, the Chalk "Rock should, I.
think, receive a separate zonal designation = its palzontological
characters are quite as striking, and far more constant than its:
lithological. Thus for example, at Twyford, near Winchester, as.
already mentioned, the zone can only be recognized by means of its-
fossils. Moreover, so far as lithological characters are concerned,
the hard bed which occurs above the Chalk Rock in Buckinghamshire:
and Bedfordshire might with equal propriety be termed ‘ chalk rock.”
If the adoption of a zonal name meet with approval, I would venture
to suggest the introduction of the term employed by Prof. Schliiter
for the same zone in North-western Germany, viz. ‘ zone of Hetero-
ceras Reussianum, which for the sake of brevity might be spoken of
as simply the ‘ Reussianwm-zone.’ In England Scaphites Geinitzi is
more abundant than H. Reussianuwm, and would have been prefer-
able for use as a zonal term, but it is not quite confined to the
Chalk Rock.

Although several authors [¢. g. 17, 21, 26, 27, 29 of the biblio-
graphical list, p. 72] have given sia of fossils, no detailed study of
the paleontology of the bed has yet been made. In this and the
following paper I propose to consider the mollusca, giving an account
of the synonymy and distribution of all the species, and also figures.
and descriptions of the new or not well-known forms. In the

Vol. 52.] OF THE CHALK ROCK. 71

synonymy I shall not, except in a few cases, include references to
works in which the species are simply recorded, but only to those
in which some description occurs.

The preservation of the fossils in the Chalk Rock is moderately
good, but the cephalopoda have scarcely ever the shell preserved.
The gasteropoda also occur most frequently as casts, but in nearly
every species at least one or two specimens have been found with
the shell remaining; and much information has been obtained by
taking wax or gutta-percha casts of the external moulds. In Ostrea
and Spondylus (Dianchora) the shell is present, but in most of the
other lamellibranchs it has disappeared. The brachiopoda and
echinoidea have nearly always, as might be expected, the shell pre-
served. The corals are in the form of casts in almost every case.

My work is based to a large extent on the collection from Cuck-
hamsley (Berks) made by the late Mr. Montagu Smith, of Trinity
College, and presented by his friends to the Woodwardian Museum ;
but for the loan of many specimens, which have been of much
service, [ am greatly indebted to several friends and correspondents,
of whom I would especially mention Mr. W. Hill, of Hitchin,
Dr. J. Morison, of St. Albans, Mr. C. Griffith, of Winchester, and
Mr. R. M. Brydone, of New College, Oxford. I have also to thank
Dr. A. W. Rowe, of Margate, and Mr. James Saunders, of Luton, for
allowing me to examine their collections and for other valuable
help ; while, in the British Museum and the Museum of Practical
Geology, Mr. G. C. Crick and Mr. KE. T. Newton have generously
helped me in examining the specimens under their charge. Mr.
Jukes-Browne has also kindly given me advice concerning the range
of some of the species.

In order to study more carefully the species described by Con-
tinental paleontologists, I have visited the Museums of Prague,
Dresden, Berlin, Hildesheim, Hanover, Brussels, and Paris; and I
would here express my gratitude to the authorities of those institu-
tions for the facilities given me.

Interature.

The following is a list of works in which descriptions of the Chalk
Rock have appeared :—

1. A.C. Ramsay, H. W. Bristow, H. Baverman, and A. Gerx1zr.— A Descrip-
tive Catalogue of the Rock Specimens in the Museum of Practical Geology.’
Second edition (1860), p. 296.

. W. Wu1TaKxer.— On the “ Chalk Rock,” the topmost bed of the Lower Chalk,
in Berkshire, Oxfordshire, Buckinghamshire, etc.’ Quart. Journ. Geol. Soc.
vol. xvii. (1861) p. 166.

. E. Hurt and W. WuiraxEer.— The Geology of Parts of Oxfordshire and Berk-
shire ’ (1861), p. 20. Mem. Geol. Survey.

4, W. WuiTakEeR.—‘ The Geology of Parts of Middlesex, Hertfordshire, Bucking-

hamshire, Berkshire, and Surrey ’ (1864), pp. 5-8. Mem. Geol. Survey.

5. W. WuiTaker.— On the Chalk of Buckinghamshire and on the Totternhoe

Stone.’ Quart. Journ. Geol. Soc. vol. xxi. (1865) p. 398.

bo

iv\)

32.
33.

MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

6. W. WuiTaKkER.—‘ On the Chalk of the Isle of Wight.’ Quart. Journ. Geol.
Soe. vol. xxi. (1865) p. 400.

7. J. SAUNDERS.—‘ Notes on the Geology of South Bedfordshire (No. IT.).’ Geol.
Mag. vol. iv. (1867) p. 543.

8. geet On some Sections of the Chalk between Croydon and Oxstead,’
1870.

9. W. WHITAKER.—‘ On the Chalk of the Southern Part of Dorset and Devon.’

Quart. Journ. Geol. Soc. vol. xxvii. (1871) p. 98.

. W. WuHITAKER.— The Geology of the London Basin. Part I.’ (1872), pp. 46,

572. Mem. Geol. Surv. vol. iv.

. C. Barrois.— Description géologique de la Craie de I’Ile de Wight.’ Ann,

Sciences Géol. vol. vi. (1875) p. 20.

. C. Barrors.—‘ Recherches sur le Terrain Crétacé Supérieur de Angleterre et

de l’Irlande ’ (1876), pp. 17, 30, 59, 64, 107, 146.

. E. C. Davey.—‘ Catalogue of Fossils from the Cretaceous Beds of Berkshire’

(1877), p. 14.

. Excursion to Wantage. Report by E. C. Davey and W. H. Hupizston,

Proc. Geol. Assoc. vol. v. (1877) p. 189 (also ‘ Records of Excursions,’ p. 285).

. W. Waitaker, W. H. Pennine, W. H. Datton, and F. J. Bennett.—The

Geology of the N.W. Part of Essex and the N.E. Part of Herts, etc. (1878),
pp. 7-9. Mem. Geol. Survey.

. A. J. JUKES-BrownE.—‘ The Subdivisions of the Chalk.’ Geol. Mag. dec. 2,

vol. vii. (1880) p. 253.

. W. H. Pennine and A. J. JuKEs-Brownze.— The Geology of the Neighbour-

hood of Cambridge’ (1881), pp. 22, 66, 130. Mem. Geol. Survey.

. J. W. Jupp.—‘ The Nature and Relations of the Jurassic Deposits which

underlie London.’ Quart. Journ. Geol. Soc. vol. xl. (1884) p. 725. [Chalk
Rock, p. 733. |

. EF. J. Bennett and J. H. Buaxzt.— The Geology of the Country between and

south of Bury St. Edmund’s and Newmarket’ (1886), p. 8. Mem. Geol.
Survey.

. W. Hiti.—‘ On the Beds between the Upper and Lower Chalk of Dover, and

their comparison with the Middle Chalk of Cambridgeshire.’ Quart. Journ.
Geol. Soc. vol. xli. (1886) p. 232.

W. WuiTakeER.—‘ The Geology of London and of Part of the Thames Valley,’
vol. i. (1889) p. 67. Mem. Geol. Survey.

. Excursion to Boxmoor and Nash Mills. Report by J. Hopxinson. Proc.

Geol. Assoc. vol. xi. (1889) p. lviii.

. Excursion to Upton and Chilton. Report by W. WuitaKEeR. Proc. Geol.

Assoc. vol. xi. (1889) p. Ixxxvili.

. A. J. JuKES-BrownE.—‘ The Geology of Upton and Chilton in Berks.’ Proc.

Geol. Assoc. vol. xi. (1889) p. 198.

. H. W. Bristow.—‘ The Geology of the Isle of Wight.’ Second edition, by

C. Rerp and A. Strawan (1889) p. 73. Mem. Geol. Survey.

. J. Morison.— Notes on the Chalk Rock.’ Trans. Herts. Nat. Hist. and Field

Club, vol. v. (1889) p. 199.

. J. SAUNDERS.— Notes on the Geology of South Bedfordshire.’ Geol. Mag.

dec. 3, vol. vii. (1890) pp. 121, 124.

. Excursion to Henley-on-Thames and Nettlebed. Report by J. H. Buaxks.

Proc. Geol. Assoc. vol. xii. (1891) p. 204.

. Winchester College Natural History Society. Geological Section [List of Chalk

Fossils |, 1891.

. A. J. JuKEs-Browne.—‘ The Geology of Devizes.’ Proc. Geol. Assoc. vol. xii.

(1892) p. 261, pl. v. f. 2, 4.

. W. Wuiraxker, S. B. J. Sxertronty, and A. J. JuxEs-Brownze.— The

Geology of South-western Norfolk and of Northern Cambridgeshire’ (1898),
p. 39. Mem. Geol. Survey.

W. F. Hume.—‘ Chemical and Micro-mineralogical Researches on the Upper
Cretaceous Zones of the South of England’ (1898), p. 53.

W. F. Hume.— The Genesis of the Chalk.’ Proc. Geo] Assoc vol. xiii. (1894)
p. 233.

Vol. 52.] OF THE CHALK ROCK. 73

II, Class CEPHALOPODA.
Order Nautiloidea.
Family Nautilide, Owen.
Genus Navritvus (Breynius, 1732), Linneeus, 1758.

NavriLus susLavieatus, d’Orbigny, 1850,

1840. Nautilus levigatus, A. d’Orbigny, ‘Paléont. Frang. Terr. Crét.’ vol. 1.
p. 84, pl. xvii.; 1850. H. B. Geinitz, ‘Das Quadersandsteingebirge oder Kreide-
gebirgein Deutschland,’ p. 110, pl. iii. f. 2 a, 6; 1853. D. Sharpe, ‘ Foss.Mollusca in
the Chalk of England,’ pt. i. (Ceph.) p. 11, pl. ii. f. la, b, 2a, b; 1854. J. Morris,
* Cat. Brit. Foss.’ ed. 2, p. 307; 1863. A. von Strombeck, Zeitschr. der deutsch.
geol. Gesellsch. vol. xv. p. 136 (pars).

1850. Nautilus sublevigatus, A. d’Orbigny, ‘ Prodrome de Paléont.’ vol. 11. p. 189 ;
1859. F. J. Pictet and G. Campiche, ‘ Descript. des Foss. du Terr. Crét. de Sainte-
Croix ’ (Pal. Suisse, ser.i. pt. i.), p. 140; 1869. E. Favre, ‘ Descript. des Mollusques
Foss. de la Craie des Environs de Lemberg,’ p. 9; 1872. A. Fritsch and U. Schlonbach,
£Ceph. bohm. Kreideformat.’ p. 21, pl. xii. f. 1; 1872. H. B. Geinitz, ‘ Das Elbthal-
gebirge in Sachsen’ (Palaeontographica, vol. xx.), pt. ii. p. 182, pl. xxxii. f. 1,1 a, 2,3;
1873. ? A. Redtenbacher, ‘Die Ceph. der Gosauschichten’ (Abhandl. d.k. k. geol.
Reichsanstalt, vol. v.), p. 95, pl. xxii. f. la, 6; 1877. A. Fritsch, ‘ Stud. im Gebiete
der bohm. Kreideformat. II. Die Weissenberger und Malnitzer Schichten,’ p. 101;
1883. A. Fritsch, ibid. III. ‘ Die Iserschichten,’ p. 90; 1889. A. Fritsch, ibid. IV.
‘Die Teplitzer Schichten,’ p. 70; 1891. A. H. Foord, ‘Cat. Foss. Ceph. Brit. Mus.’
part i. p. 242; 1893. A. Fritsch, op. cit. V. ‘ Priesener Schichten,’ p. 73.

1852. Nautilus cretaceus, C. G. Giebel, ‘Fauna der Vorwelt,’ vol. iii. p. 149;
1858. W. A. Ooster, ‘Cat. Céph. Foss. des Alpes Suisses,’ pt. iii. p. 14.

_ Remarks.—This species was well described by Sharpe in his
monograph on the Mollusca of the Chalk (1853); it is more closely
allied to Nautilus Bouchardianus, d’Orbigny, than to any other
species, but is easily distinguished from it by the absence of an
umbilicus. The largest specimen that I have seen from the Chalk
Rock was collected by Dr. Morison from the Luton cutting, and has
a diameter of 37 inches. A mandible, which probably belongs to
this species, was obtained by Mr. R. M. Brydone from the Chalk
Rock of Winchester.

Distribution — British Isles: Lower Greensand; Upper, Middle,
and Lower Chalk. Chalk Rock of Oldborough Castle, Cuckhamsley,
Luton cutting, Boxmoor, Hitchin, Reed near Royston, and Under-
wood Hall near Dullingham. White Limestone of the North of
Ireland. France: zone of Epiuster brevis at Fontaine-les-Vervins,
zone of Inoceramus labiatus east of the Paris basin, and Middle
Turonian of Loir-et-Cher. D’Orbigny records it from the Chalk
of Martou near Rochfort, and Royan (Charente-Inférieure). Switzer-
land: Alpes d’Appenzell and Alpes de Schwytz. Belgiwm: Maes-
trichtian of Limbourg (according to Mourlon). Sawony: noc.
labiatus beds of Leutewitz and Briessnitz. Planer-Kalk of Strehlen
and Weinbohla; and the Scaphites-beds of Zatzschke. Bohemia:
Turonian* and Priesen Beds of various localities, ¢. g. Raudnitz,
Teplitz, Bavaria: Kagerhéh Beds of Winzerberg, near Regens-
burg. Galicia: Chalk of Nagozany.

1 In this paper I include in the Turonian the Weissenberg, Malnitz, and
Teplitz Beds.

74. MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

Order Ammonoidea.

Family Lytoceratid, Neumayr.
Genus Prycuoceras, d’Orbigny,* 1840.
PrycHoceras SmirHi, sp. nov. (Pl. II. figs. 1, 2.)

Description.—Shell circular in section, ornamented with simple
continuous ribs, which become oblique where the shell is recurved.
Suture-line imperfectly known; siphonal lobe large; siphonal.
saddle broad, bifid.

Affinities.—Ptychoceras gaultinus of Pictet (‘Moll. Foss. des
Grés Verts des Envir. de Genéve,’ 1847, p. 139, pl. xv. f. 5, 6) is
near to this species, but differs in that the ribs suddenly become
much more prominent and distant where the shell is recurved.

Remarks.—The type of this species is in the Woodwardian
Museum ; it is named in memory of the late Montagu Smith.

Distribution.—Chalk Rock of Cuckhamsley, and Winchester.

Genus Hamirss, Parkinson, 1811.

A fragment of a shell, apparently belonging to this genus, is in
the Montagu Smith collection from Cuckhamsley; it has a length of
21 millim., and is provided with ten broad ribs, but is not sufficiently
perfect for specific determination.

Genus Hrrrroceras, d’Orbigny,” 1850.

Herrroceras Revssianum (d’Orbigny), 1850. (Pl. II. figs. 3-5.)

1841. ? Hamites plicatilis, ¥. A, Roemer (non Sowerby), ‘ Verstein. norddeutsch.
Kreidegeb.’ p. 94, a xiv. f.7; 1843. H. B. Geinitz, ‘Die Verstein. von Kieslings-
walda,’ p 8, pl. v. f.2; 1845. A. E. Reuss, ‘ Verstein. béhm. Kreideformat.’ p. 23,
pl. vu. f. 5, 6,

1843. Turrilites polyplocus, var., H. B. Geinitz, ‘Die Verstein. von Kieslings-
walda,’ p. 8, pl. v. f. 4.

1845. ? Turrilites Astierianus, A. KE. Reuss, ‘ Verstein. bohm. Kreideformat.’ p. 24,
pl. vii. f. 7; 1852. C. G. Giebel, ‘Fauna der Vorwelt,’ vol. ii. p. 845 (partim).

1846. Hamites armatus, H. B. Geinitz, ‘Grundriss der Versteinerungskunde,”

p. 304, pl. xii. f. 3; 1850. H. B. Geinitz, ‘Das Quadersandst. oder Kreidegeb. in
Teaieeuiatd® p- 192 (partim) ; 1852. C. G. Giebel, ‘Fauna der Vorwelt,’ vol. iii.
p. 296 ( partim).

1850. Hamites Astierianus, H. B. Geinitz, ibid. p. 120 ( partim).

1850. Hamites Reussianus, A. d’Orbigny, * Prodr. de Paléont.’ vol. ii. p. 216.

1850. ? Turrilites Reussii, A. d@’Orbigny, zbid. p. 216.

1850. ? Turrilites plicatilis, A. d’Orbigny, ibid. p. 216.

1850. Helicoceras polyplocus, A. d’Orbigny, ibid. p. 216.

1861. Anisoceras Reussianus, ¥. J. Pictet and G. Campiche, ‘ Descript. des Foss.
du Terr. Crét. des Envir. de Ste. Croix’ (Paléont. Suisse, ser. 3, part 2), p. 76.

1870. Helicoceras annulifer, F. Romer, ‘Geol. von Oberschlesien,’ p. 320,
pl. xxxvi. £ 2.

1871. Heteroceras Reussianum, C. Schliiter, ‘Ceph. oberen deutsch. Kreide,’
p. 109, pl. xxxu. f. 18-21, pl. XXxiil, f.1; 1878. C. Barrois, Ann. Soc. Géol. du Nord,
vol. v. p. 404; 1887. A. Peron, ‘Notes pour servir 4 l’Hist. du Terr. de Craie,’ Bull.
Soc. Sci. hist. et nat. de VYonne, ser. 3, vol. xii. p. 138.

1 ¢Pal. France. Terr. Crét.’ vol. i. p. 554.
* Prodr. de Pal. vol. ii. p. 102.

Vol. 52. | OF THE CHALK ROCK. 75

1872. Helicoceras armatus, A. Fritsch and U. Schlonbach, ‘Ceph. d. bohm.
Kreideformat.’ p. 47, pl. xiii. f. 16?, pl. xiv. f. 14-19 (? 14, 15, 16, 181), pl. xvi. f. 9?

1874. Helicoceras Reussianum, H. B. Geinitz, ‘Das Elbthalgebirge in Sachsen ’
(Palaeontographica, vol. xx.), part ii. p. 193, pl. xxxv. f. 11, 12; 1883. P A. Fritsch,
* Studien im Gebiete der bohm. Kreideformat. III. Die Iserschichten,’ p. 92; 1889.
A. Fritsch, ibid. IV. ‘ Die Teplitzer Schichten,’ p. 71, f. 44; 1893. A. Fritsch, ibid.
V. ‘ Priesener Schichten,’ p. 79, f. 62.

Description.—Shell spiral, the first few (? 5 or 6) whorls in con-
tact, the later ones free. Whorls circular or slightly elliptical in
section, ornamented with distant, oblique, prominent ribs (or
varices), each of which is produced at the same levels into four
short spines. Between these large ribs are smaller ones, commonly
four, but sometimes three, five, or six. All the ribs, particularly
the large ones, become less distinct on the inner (anti-siphonal)
margin of the whorls.

The suture-line is much divided. Siphonal lobe of moderate size,
divided by a median saddle. Superior-lateral lobe larger than the
inferior-lateral lobe; superior-lateral saddle a little larger than
the siphonal saddle, both narrow-stemmed: these lobes and saddles
deeply but not symmetrically bipartite, the divisions also bifid and
not symmetrical. Inferior-lateral saddle small, narrow, bipartite.
Internal lobe narrow and deep.

Remarks.—The specimens found in the Chalk Rock consist in
most cases of portions of some of the later whorls only; but one
example from S.W. of Dunstable in the Museum of Practical
Geology (No. J R 2193) shows two of the earlier whorls in contact.
This species has been placed by Schliter in the genus Heteroceras,
but by Geinitz, Romer, and Fritsch in Helicoceras.

Distribution.—England: Chalk Rock of Cuckhamsley, Hitchin,
Luton cutting, and 17 mile 8.W. of Dunstable Church. France:
zone of Epiaster brevis at Fontaine-les-Vervins, and east of the
Paris basin. North-western Germany: confined to the zone of Het. |
Reussianum, found at Salzgitter in Hanover, and Oerlinghausen in
the Teutoburger Wald. Sawony: Planer-Kalk of Strehlen, and
Weinbohla. Silesta: Scaphites-beds of Oppeln. Bohemia: Turo-
nian and Priesen Beds of numerous localities, ¢. g. Priesen, Kistra,
Hundorf.

Hereroceras, sp. (PI. II. figs. 6-8.)

Deseription.—Shell dextral or sinistral. Whorls elliptical in sec-
tion, crossed by deep oblique furrows (two or three on each whorl),
and ornamented with transverse, simple, oblique ribs; on some of
the earlier whorls the direction of the obliquity changes, so that the
ribs of one whorl make with those of the next an angle of about
120°; the change takes place at one of the furrows. Umbilicus
very wide.

Suture-line much ramified ; siphonal lobe of moderate size, with
a median saddle. Superior-lateral lobe twice as large as the

* Figures 14, 15, and 16 are referred by Schliiter to Helicoceras reflexwiz
(Quenstedt).

76 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

inferior-lateral lobe, both deeply divided, the divisions bifid and.
not quite symmetrical. Siphonal saddle a little larger than the
superior-lateral saddle, both narrow-stemmed and deeply and un-
symmetrically divided.

Affinities—This species is near to Astierianus of d’Orbigny * from
the Upper Gault of Escagnolle, but it is distinguished by the wider
umbilicus and by the change in direction of the ribs on some of the
whorls. It is also allied to Helicoceras indicum, Stoliczka,” from the
Arrialoor Group of Vegahoor, with which it may prove to be iden-
tical when that form is better known. HH. Reussianum differs in
having the varices continued on the spire, just as on the free
whorls.°

Distribution.—Chalk Rock of Winchester, Lichfield (Hants),
Cuckhamsley, Luton cutting, and Hitchin.

Genus Bacunires, Lamarck, 1801.

BacuLitEs BoHEMICcUS, Fritsch and Schlonbach, 1872. (Pl. IL.
figs. 9, 10.)

1843. Baculites anceps, H. B. Geinitz, ‘ Die Verstein. von Kieslingswalda,’ p. 9.

1850. Baculites baculoides, H. B. Geinitz, ‘ Das Quadersandst. oder Kreidegebirge
in Deutschland,’ p. 122; 1874. H. B. Geinitz, ‘Das Elbthalgebirge in Sachsen’
(Palaeontographica, vol. xx.), part ii. p. 195, pl. xxxv. f. 17-21.

1872. Baculites Fauwjassi, Lamarck, var. bohemica, A. Fritsch and U. Schlonbach,
*Ceph. der béhm. Kreideformat.’ p. 49, pl. xiii. f. 23-25, 29, 80; 1893. A. Fritsch,
‘Stud. im Gebiete der bohm. Kreideformat. V. Priesener Schichten,’ p. 80, f. 63;
1895. J. J. Jahn, Jahrb. der k. k. geol. Reichsanst. vol. xlv. p. 133, pl. vii. f. 8.

1875. Baculites bohemicus, C. Barrois, Ann. Soc. Géol. du Nord, vol. v. p. 403.

1876. Baculites cf. bohemicus, C. Schliiter, ‘ Ceph. oberen deutsch. Kreide,’ p. 140,
pl. xxxix. f. 1-5.

Description.—Shell increasing in diameter very slowly, section
elliptical, siphonal margin rounded; last chamber with a curved
projecting portion on the siphonal side. Surface of shell with
faintly marked ribs or undulations, which pass over the siphonal
margin, where they are strongest, and curve posteriorly on the
lateral areas, becoming indistinct or altogether disappearing on the
anti-siphonal margin. There are also at intervals broad furrows,
which run parallel to the ribs and become less distinct on the anti-
siphonal margin (these, however, are not seen on all specimens).

Suture-line:—siphonal lobe rather broad, divided by a median
saddle; superior-lateral lobe rather deep, bifid, larger than the
inferior-lateral ; internal (anti-siphonal) lobe small; siphonal saddle ~
broad, deeply bifurcate, each part being also bifid; lateral saddles
similarly bifurcate, the superior-lateral being about half the size
of the siphonal saddle.

Affinities.—This species is related to Baculites vertebralis, Lamk.
(=Fawasi, Lamk.), and to B. baculoides, Mant. It differs from
B, vertebralis in having the siphonal saddle nearly twice as broad as
the superior-lateral saddle, and the ribs and grooves appear to be

1 «Pal. Frang. Terr. Orét.’ vol. i. (1840) p. 578, pl. exl. f. 8-11.
2 «Foss. Ceph. Cret. Rock. S. India’ (1866), p. 184, pl. Ixxxvi. f. 1-2.
3 See Schliiter, ‘Ceph. oberen deutsch. Kreide’ (1871), pl. xxxii. f. 14-16, 20,

Vol. 52.] OF THE CHALK ROCK. rin

better marked. The suture-line of B. baculoides has not been
observed in English specimens ; but the figure given by d’Orbigny
from a French example differs from B. bohemicus in the greater
length of the lobes and saddles, and in having the siphonal saddle
and the superior-lateral saddle of about the same size.

Remarks.—Geinitz considers that B. bohemicus is identical with
B. baculoides of Mantell, which is found in the Lower Chalk of
Sussex, etc., and he regards the forms figured under the same name
by d’Orbigny from the French Cenomanian as distinct, proposing to
place them in his species sub-baculoides ; he takes as his types speci-
mens found on the same horizon in Saxony. The specimen from
the Priesen Beds of Bohemia figured by Fritsch (1893) is of great
interest, as it shows the earliest part of the shell with the initial
chamber. The examples of B. bohemicus found in the Chalk Rock
are far from perfect, and the mode of preservation often leaves much
to be desired; the longest portion that I have seen measured
87 mm., with a thickness of 9 mm. and a height of 12 mm.

Localities—England : Chalk Rock of Winchester, Lichfield
(Hants), Cuckhamsley, Boxmoor, and Luton. France: zone of
Terebratulina gracilis east of the Paris basin, zone of Epiaster brevis
at Fontaine-les-Vervins. North-western Germany: zone of Hetero-
ceras Reussianum at Oerlinghausen, Langelsheim, Heiningen, etc.,
and rarely in the zones of Inoceramus Brongniartt and I. Cuviert.
Saxony: Pliner-Kalk (zone of J. Brongniartc) of Strehlen and
Weinbohla. Bohemia: Turonian and Priesen Beds of Priesen,
Waldeck, Bohmisch-Kamnitz, and Leneschitz.

Family Prionotropide, Zittel.
Genus Prionocyctus, Meek,’ 1872.

Prionocyctus Neprunt (Geinitz), 1849. (PI. II. fig. 11, and Pl. III.
figs. 1-4.)

1842. Ammonites falcatus, H. B. Geinitz (non Mantell), ‘Char. der Schichten u-
Petrefacten der sachs.-béhm. Kreidegeb.’ (Heft 3), p. 67.

1850. Ammonites Neptuni, H. B. Geinitz, ‘ Das Quadersandst. oder Kreidegebirge
in Deutschland, p. 114, pl. ii. f. 3; 1872. C. Schliiter, ‘Ceph. oberen deutsch.
Kreide,’ p. 36, pl. xi. f. 1-7; 1872. A. Fritsch and U. Schlonbach, ‘Ceph. bohm.~
Kreideformat.’ p. 30, pl. ii. f. 4, pl. xiv. f. 3; 1874-5. H. B. Geinitz, ‘Das Elbthal-
gebirge’ (Palaeontographica, vol. xx.), pt. 1, p. 280, pl. Ixil. f. 4; pt. 2, p. 185,
pl. xxxvi. f. 4; 1877. A. Fritsch, ‘Stud. im Gebiete der bohm. Kreideformat. II. Die
Weissenberger und Malnitzer Schichten,’ p. 101; 1887. A. Peron, ‘ Notes pour servir
a ’Hist. du Terr. de Craie,’ Bull. Soc. Sci. hist. et nat. de Yonne, ser. 3, vol. xii.

. 136.
‘ 1855. ? Ammonites Bravaisianus, D. Sharpe, ‘Foss. Mollusca in the Chalk of
England’ (Ceph.), p. 52, pl. xxii. f. 8, 9.

_ Deseription.—Shell discoidal, carinate, with a wide umbilicus.
Whorls rather more than one-third enclosing, subquadrangular in
section, ornamented with very strong and slightly oblique ribs, each
of which bears near the siphonal margin two tubercles, the inner

1 F, B. Meek, in Hayden’s Ann. Rep. U.S. Geol. Survey of the Territories:
(1872), p. 298 (footnote), and ibid. vol. ix. (1876) p. 452.

78 MR. H. WOODS ON THE MOLLUSCA [ Feb. 1896,

being a little the smaller. After passing the inner tubercle the
ribs bend forward to the outer, and again forward to the carina.
The carina is strongly dentate, one tooth corresponding to each rib.
The ribs are of two sizes!; the longer ones start from the umbilical
margin and bear there a small tubercle, but the smaller ones, which
alternate with these, begin a short distance from the margin and
do not bear at the starting-point a tubercle.

Suture-line: the lobes and saddles not much divided, the saddles
much larger than the lobes. Siphonal saddle larger than the
superior-lateral and unsymmetrically bipartite. Siphonal lobe
rather deep, divided by a saddle; superior-lateral lobe larger than
the preceding and with unsymmetrical lobules; inferior-lateral lobe
about half the size of the superior-lateral.

Affinities.—This species is related to Ammonites Germari of
Reuss,” but is distinguished from it by the dentation of the carina
being much coarser. <A. dentato-carinatus of Romer * differs from
this in having only one row of tubercles near the siphonal margin.
P. Neptuni is distinguished from the young forms of Ammonites
Woolgari, Mantell, by the greater breadth of the ribs. Sharpe
described and figured as Ammonites Bravaisianus, d’Orbigny, two
specimens from the Middle Chalk (probably Chalk Rock) of Dover,
which are probably identical with the species under consideration ;
the originals were in the collections of Mr. J. W. Flower and
Mr. 8S. J. Mackie, but I have not been able to see them.

D’Orbigny’s Ammonites Bravaisianus, from the ‘ grés vert supé-
rieur’ of Uchaux and Mondragon (Vaucluse), resembles P. Neptuni
in the form of the shell and the ribs, but the carina is entire.
D’Orbigny’s types are preserved in the Paleontological Laboratory
of the Paris Museum; the largest has a diameter of 17 mm. The
figures given in the ‘ Paléontologie Francaise’ do not convey quite
a correct idea of the form of the ribs.

Localities.—England: Chalk Rock of Oldborough Castle, Cuck-
hamsley, Prince’s Risborough, Luton cutting, Dunstable, and Hitchin.
France: zone of Holaster planus in the Yonne, zone of Hpiaster brevis
of Saint-Clément, zone of Terebratulina gracilis east of the Paris basin,
Senonian (F of M. Lambert) of Armeau. North-western Germany:
confined to the zone of Het. Reussianum, found at Bielefeld, Ringe-
berge, Heiningen, and Windmiihlenberge near Salzgitter. Saxony:
in the Mergelschichten (I. Brongniarti-beds) of Walkmiihle near
Pirna ; Geinitz records one specimen from the Pliner (Cenomanian)
of Plauen, near Dresden. Bohemia: Malnitz Beds, near Laun.

1 In some specimens (¢. g. Pl. III. fig. 3) the difference in size of the ribs is
very slight.

2 A. E. Reuss, ‘ Die Verstein. d. bohm. Kreideformat.’ 1845, p. 22, pl. vii.
f.10. See also A. Fritsch and U. Schlonbach, ‘Ceph. bohm. Kreideformat.’
p- 29, pl. xiv. f. 1, 2, pl. xvi. f. 7; and C. Schliiter, ‘Ceph. oberen deutsch.
Kreide,’ p. 41, pl. xi. f. 15-17.

3 KF, Romer, ‘ Die Kreidebild. v. Texas,’ 1852, p. 33, pl, i. f. 2.

Vol) 52.] OF THE CHALK ROCK. 79

Family Desmoceratide, Zittel.
Genus Pacuyniscus, Zittel, 1884.

PacHYDIscUS PERAMPLUS (Mantell), 1822.

1822. Ammonites peramplus, G. Mantell, ‘ Foss. S. Downs,’ p. 200 1822. J.
Sowerby, ‘ Min. Conch.’ vol. iv. p. 79, pl. ccclvii.; 1840. A. d’Orbigny, ‘ Paléont.
Frang. Terr. Crét.’ vol. i. p. 333, pl. c. f. 1,2; 1841. F. A. Romer, ‘ Die Verstein.
des norddeutsch. Kreidegeb.’ p. 87; 1842. H. B. Geinitz, ‘ Char. der Schichten u.
Petrefacten des sachsisch.-béhm. Kreidegeb.’ Heft 3, p. 67, pl. xi. f.2; 1845. A. E.
Reuss, ‘ Die Verstein. d. bdhm. Kreideformat.’ p. 21; 1846. H. B. Geinitz, ‘ Grundr.
der Verstein.’ p. 297 I(partim); 1846. F. v. Quenstedt, ‘ Petrefact. Deutschlands,’
vol. i. Ceph. p. 216; 1850. A. d’Orbigny, ‘ Prodr. de Paléont.’ vol. ii. p. 189; 1850.
H. B. Geinitz, ‘ Quadersandstein. oder Kreidegeb. in Deutschland,’ p. 116, pl. v. f. 1,
2, 3; 1852. C. G. Giebel, ‘Fauna der Vorwelt,’ vol. ili. p. 423; 1853. D. Sharpe,
* Foss. Mollusca in the Chalk of England’ (Ceph.), p. 26, pl. x. f. 1-3; 1854.
J. Morris, ‘ Cat. Brit. Foss.’ ed. 2, p. 298; 1859. A. v. Strombeck, Zeitschr. der
deutsch. geol. Gesellsch. vol. xi. p. 44; 1860. W. A. Ooster, ‘Cat. Céph. Foss. des
Alpes suisses,’ part iv. p. 150; 1860. F. J. Pictet and G. Campiche, ‘ Foss. du Terr.
Crét. de Ste-Croix,’ Pal. Suisse, pt. i. p. 354; 1865. ? EF. Stoliczka, ‘ Foss. Ceph. Cret.
Rocks S. India,’ p. 180, pl. Ixv. f. 1, 2; 1866. C. Schliiter, Zeitschr. der deutsch.
geol. Gesellsch. vol. xviii. p. 71; 1870. F. Romer, ‘ Geol. von Oberschlesien,’ p. 319,
pl. xxxv. f. 5; 1870. C. Schliiter, Neues Jahrb. fiir Min. etc. p. 945; 1872. C.
Schliiter, ‘Ceph. ober. deutsch. Kreide,’ p. 31, pl. x. f. 7-14; 1872. A. Fritsch and
U. Schloénbach, ‘ Ceph. der bohm. Kreideformat.’ p. 38, pl. viii. f. 1-4, pl. xiv. f. 4, 5;
1874. H. B. Geinitz, ‘ Das Elbthalgebirge in Sachsen’ (Palaeontographica, vol. xx.),
part ii. p. 189, pl. xxxiv. f. 4-7 ; 1877. A. Fritsch, ‘ Studien im Gebiete der bohm.
Kreideformat. II. Die Weissenberger und Malnitzer Schichten,’ p. 102; 1883.
Fritsch, ibid. ‘III. Die Iserschichten,’ p. 91; 1878. F. Dixon, ‘Geol. Sussex,’ ed. 2,
p- 386, pl. xxvii. f. 22; 1878. C. Barrois, Ann. Soc. Géol. du Nord, vol. v. p. 403.

1840. Ammonites Prosperianus, A. @Orbigny, ‘ Paléont. Frang. Terr. Crét.’ vol. i.
p- 335, pl. c. f. 3,4; 1850. F. Dixon, ‘Geol. Sussex,’ p. 359, pl. xxvii. f. 22; 1852.
€. G. Giebel, ‘Fauna der Vorwelt,’ vol. i. p. 424.

1840. Ammonites lewesiensis, H. B. Geinitz, ‘Char. der Schichten u. Petrefacten
des sachs. Kreidegeb.’ Heft 2, p. 39, pl. xii. f. 2 (partim).

1842. Ammonites Decheni, H. B. Geinitz, ‘ Char. der Schichten u. Petrefacten des
sachsisch.-béhm. Kreidegeb.’ Heft 3, p. 66 (partim); 1846. H. B. Geinitz, ‘ Grundr.
der Verstein.’ p. 297 (partim).

1852. ? Ammonites flaccidicostata, F. Romer, ‘ Die Kreidebildungen von Texas,’
p. 33, pli. f. 1a, b.

1865. ? Ammonites Vaju, F. Stoliczka, ‘ Foss. Ceph. Cret. Rocks 8. India,’ p. 132,

]. Ixv. f. 3.
F 1869. (?) Ammonites fraternus, W. M. Gabb, Geol. Survey of California: Palzon-
tology, vol. ii. p. 137, pl. xxiii. f. 15, 154, bd.

1873. ? Ammonites Draschei, A. Redtenbacher, ‘ Die Ceph. der Gosauschichten,’
Abhandl. d. k. k. geol. Reichsanstalt, vol. v. p. 123, pl. xxx.fila,b. :

1889. Ammonites (Pachydiscus) peramplus, A. Fritsch, ‘Studien im Gebiete der
bohm. Kreideformat. IV. Die Teplitzer Schichten,’ p. 70, f. 41; 1893. Fritsch, ibid.
‘ V. Die Priesener Schichten,’ p. 76.

Description.—Shell discoidal, whorls very convex, about two-
thirds enclosed, siphonal area rounded. Umbilicus deep, walls
almost vertical. Ribs well-marked, rounded, curving forwards, and
continuous on the siphonal area. At the umbilical margin of each
whorl there are six or seven prominent sharp tubercles, each of
which gives rise to one, or occasionally two, primary ribs ; between
these there are usually three (but sometimes more or fewer) smaller
ribs which start from the middle of the lateral area of the whorl.

The suture-line is figured by Sharpe (pl. x. f. 2a) and by Geinitz
(1874, vol. ii. pl. xxxiv. f. 7); the superior-lateral lobe is trifurcate,
a little larger than the inferior-lateral, which is also trifurcate ;
siphonal and lateral saddles bipartite, superior-lateral a little larger

30 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

than the siphonal saddle, inferior-lateral about two-thirds the size
of the superior-lateral saddle.

In older individuals the whorls become more flattened, and the
tubercles and ribs (11 to 14 on the last whorl) less distinct; the
latter are less curved and all start from the tubercles at the margin
of the umbilicus and often disappear on the siphonal area. In
senile forms the shell is quite smooth.

Rtemarks.—The average diameter of this species in the Chalk
Rock is 14 inch; Dr. Morison has a specimen 8 inches in diameter —
from the Luton cutting. In the zones of the Middle Chalk below
the Chalk Rock it is often much larger, being sometimes more than
a foot in diameter. In one or two cases only have I seen portions
of the shell preserved.

The specimens described by Mantell came from near Lewes and
Eastbourne; and, although he gave no figures, there can be no
doubt whatever about the identity of the species. Had there been
any, it would be removed by the fact that the specimen figured by
Sowerby a year later in the ‘ Mineral Conchology’ was presented
to him by Mantell himself. Sowerby gave only one figure, that of
a rather old individual 9 inches in diameter. D’Orbigny figured in
the ‘ Paléontologie Francaise’ the adult and young forms under
the names of Ammonites peramplus and Ammonites Prospertanus
respectively ; at the same time, he stated that the latter might be a
young individual of the former, but not having been able to observe
a passage between the two, he would regard them as distinct species.
However, almost all later authors, except Dixon (‘Geol. Sussex,’
1850), have considered Prospertanus as a synonym of peramplus.
Good figures of this species, showing examples of different ages, are
given by Sharpe; his specimens came from the Middle Chalk
(probably Chalk Rock) of Hertfordshire and Wiltshire.

Specimens from the Trichinopoly Group of the north-west of
Anaupaudy referred to this species are described and figured by
Stoliczka ; but these differ from the European examples in the smaller
ribs forming a tubercle ‘at the point where they are curved
forward.’ Stoliczka remarks (p. 131), ‘ D’Orbigny’s Am. peramplus
seems to differ very considerably from the original English figures,
while his Am. Prosperianus is identical with them.’ ‘This is
certainly an erroneous observation, for Sowerby’s figure agrees very
closely with d’Orbigny’s peramplus. Stoliczka also figures under
the name of Ammonites Vaju a specimen from the Trichinopoly
Group of the north-west of Anaupaudy, which, if not identical with
peramplus, is certainly its representative form.

Ammonites flaccidicostata, described by Romer from Guadalupe in
Texas, is near to peramplus, but it has only one small rib between
the larger ones.

Ammonites fraternus of Gabb, from the Martinez group of
Benicia, California, differs only in the form of the suture-line—the
siphonal saddle is more divided than in peramplus, and is larger
than the superior-lateral saddle.

The form described by Redtenbacher under the name of Ammonites

Vol. 52. | OF THE CHALK ROCKg - 81

Draschei, from the Gosau Beds, is probably identical with peramplus,
but the suture-line is rather different.

The older individuals of P. peramplus resemble closely Mantell’s
Am. lewesiensis ; but, according to Sharpe,* ‘the young of the two
species have no resemblance, A. lewesiensis being nearly smooth,
and the other ornamented with numerous ribs.’

The types of Pachydiscus peramplus cannot be identified with
certainty, since Mantell gave no figures; but specimens in his
collection in the British Museum agree well with his description.
Sowerby’s specimen is not in the British Museum, nor is the one
figured by Dixon. One of the examples figured by Sharpe is in the
Museum of the Geological Society; and of the others, which were
collected by Mr. W. Cunnington, one (fig. 3) is in the British
Museum.

Distribution.—England: Middle Chalk. Chalk Rock of Win-
chester, Arn Hill near Warminster, Aston Rowtant, Prince’s Ris-
borough, Berkhampstead, Boxmoor, Luton railway-cutting, Dun-
stable, Hitchin, Barkway, Reed near Royston, and Underwood Hall
near Dullingham.

France: zones of Rh. Cuviert and P. peramplus in the Loir-et-Cher,
zone of Ter. gracilis east of the Paris. basin, zone of Epiaster brevis
at Fontaine-les-Vervins, zone of Micr. breviporus in the Yonne.
Switzerland: Alps of Appenzell. North-western Germany : common
in the zone of Het. Reussianum and found near Salzgitter, at
Heinigen near Bérsum, Klein-Dohren near Liebenburg, and Rheine
in Westphalia. Rare in the zone of Jnoc. Brongniarti, at Buren in
Westphalia, etc. Also rare in the zone of Inoc. Cuviert of Rothen-
felde, and Windmihlebergen near Salzgitter. Sawvony: Planer-
Kalk of Strehlen and Weinbohla. noc. labiatus-beds of Rottwerns-
dorf and Leutewitz. Stlesia: Scaphites-beds of Oppeln. Bohemia:
Ranges through the Turonian and the Priesen Beds, found at
Teplitz, Lenesic, Lobositz, Popelz, etc. Bavaria: Kagerhoh Beds
of Galgenberg, Winzerberg, and Kagerhoh.

[Systematic position’ uncertain. |

Genus Scaruites, Parkinson, 1811.

Scapuires Gernirzi, D’Orbigny, 1850. (PI. III. figs. 5-7.)

1840. Scaphites equalis, H. B. Geinitz, ‘Charakt. der Schichten u. Petrefacten
der sachsischen Kreidegeb.’ Heft 2, p. 40; 1845. A. E. Reuss, ‘ Verstein. bohm.
Kreideformat.’ p. 23; 1846. H. B. Geinitz, ‘Grundriss der Versteinerungskunde,’
p. 301, pl. xii. f. 1 (partim) ; 1850. H. B. Geinitz, ‘Das Quadersandsteingebirge
oder Kreidegeb. in Deutschland, p. 116 (partim); 1852. C. G. Giebel, ‘Fauna der
Vorwelt,’ vol. iil. p. 331 (partim).

1841. Scaphites costatus, F. A. Romer, ‘ Verstein. norddeutsch. Kreidegeb.’ p. 90 ;
1842. H. B. Geinitz, ‘Charakt. der Schichten u. Petrefacten der sdchsisch.-béhm. -
Kreidegeb.’ Heft 3, p. 67; 1865. F. A. Romer, ‘Die Quadraten-Kreide des Sub-
merberges bei Goslar,’ Palaeontographica, vol. xiii. p. 198.

1841. Ammonites Cotte, F. A. Romer, ‘ Verstein. norddeutsch. Kreidegeb.’ p. 86,
pl. xiii. f. 4; 1845, A. E. Reuss, ‘ Verstein. béhm. Kreidef.’ p. 21, pl. vii. f. 11.

1850. Scaphites Geimitzi, A. d’Orbigny, ‘ Prodrome de Paléont.’ vol. ii. p. 214;

* Sharpe, ‘Foss. Moll. in Chalk of England (Ceph.),’ p. 46.
Q.J.G.S. No. 205. | P

82 MR. H, WOODS ON THE MOLLUSCA [Feb. 1896,

1861. F. J, Pictet and G. Campiche, ‘Descript. des Foss. du Terr. Crét. des Envir.
de Sainte-Croix,’ Paléont. Suisse, ser. 3, pt. ii. p. 21; 1865. F. A. Romer, ‘Die
Quadraten-Kreide des Submerberges bei Goslar,’ Palaeontographica, vol. xiii. p. 198;
1866. C. Schliiter, Zeitschr. d. deutsch. geol. Gesellsch. vol. xviii. p. 73; 1868. C. G.
Giimbel, ‘Geogn. Beschreib. des Kénigreichs Bayern,’ vol. ii. p. 764; 1870. F. Romer,
‘Geol. von Oberschlesien,’ p. 320, pl. xxxv. f. 6; 1872. C. Schliiter, ‘Ceph. d.

ober. deutsch. Kreide,’ p. 75, pl. xxiii. f. 12-22, pl. xxvii. f. 9; 1872. A. Fritsch’

and U. Schlénbach, ‘Ceph. bohm. Kreideformat.’ p. 42, pl. xiii. f. 7, 8, 10, 12, pl. xiv.
f. 11; 1874. H. B. Geinitz, ‘Das Elbthalgebirge in Sachsen’ (Palaeontographica,
vol. xx.), part ii. p. 191, pl. xxxv. f. 1-4; 1877. A. Fritsch, ‘Stud. im Gebiete der
béhm. Kreideformat. II. Die Weissenberger und Malnitzer Schichten,’ p. 102; 1883.

Fritsch, 2béd. ‘III. Die Iserschichten,’ p. 92, f. 53; 1889. Fritsch, ibid. ‘IV. Die:

Teplitzer Schichten,’ p. 71, f. 43; 1893. Fritsch, ibid. ‘V. Die Priesener Schichten,’

p-76; 1895. J. J. Jahn, Jahrb. der k. k. geol. Reichsanst. vol. xlv. p. 133, pl. viii. f. 3.

1855. Ammonites wiltonensis, D. Sharpe, ‘ Foss. Moll. in the Chalk of England,’
(Ceph.) pt. i. p. 53, pl. xxiii. f. 10 a-e.

1865. Scaphites striatus, F. A. Romer, ‘Die Quadraten-Kreide des Submerberges
bei Goslar,’ Palaeontographica, vol. xiii. p. 198. ,

1868. Scaphites Cottai, C. G. Giimbel, ‘Geogn. Beschreib. des Konigreichs
Bayern,’ vol. i. p. 764.

Description.—Shell flattened, or sometimes rather convex;

siphonal margin rounded. The greatest width is attained in the
straight part of the shell, midway between the involute part and
the recurved portion; the inner margin of this part is nearly

straight, the siphonal margin is regularly convex. The surface of |

the shell is ornamented with numerous ribs which are continuous
across the siphonal margin; the number and proximity of these
vary somewhat in different specimens. On the involute portion
of the shell there are between two and three times as many on the
siphonal area as on the lateral area; this is due partly to the fact
that the ribs in many cases bifurcate before the siphonal area is
reached, and partly to the intercalation of new ribs. On the
lateral area of the evolute part, and slightly nearer the siphonal
than the internal margin, is a row of from seven to nine rather
blunt tubercles, which commences at about the middle of the
straight part and ends before the aperture is reached. Each
tubercle gives rise on the inner side to a single rib, and on the
siphonal side to a pair of ribs, and between these pairs one, or some-
times more, ribs are intercalated. Between the last tubercle and
the aperture of the shell, the ribs originate from the inner margin
of the whorl, sometimes bifurcating, sometimes remaining single.
In a few specimens the row of tubercles is rather indistinct.

In one small specimen the aperture of the shell has a projecting
lip. The body-chamber commences where the shell becomes evolute.

Suture-line: saddles much broader than the lobes. Siphonal
lobe large and deep, about twice the size of the superior-lateral
lobe, which is bifid, inferior-lateral lobe small, trifurcate. Siphonal
saddle broad, bipartite, the outer division larger than the inner.
Superior-lateral saddle about half the size of the siphonal saddle,
bipartite and not quite symmetrical. Inferior-lateral saddle smaller,
slightly bifid.

Remarks.—The largest example that I have seen has a length of
45mm. There are two forms of this species, a thick and a thin
one, and these can be distinguished in individuals of all sizes; it is
possible that the difference may be due to sex.

This form was first described by Geinitz, who, however, referred

Wal? 52.) | OF THE CHALK ROOK. 83

it to S. equalis of Sowerby. D’Orbigny recognized it as being
‘distinct, and gave it the name Grevnitz, but it was first figured as
‘such by Romer (1870). Later figures and descriptions have been
given by Schliiter, Fritsch, and Geinitz.

Ammonites Cotte of Romer (1841) has been shown to be simply
‘the involute part of Scaphites Geinatzi. The same, I believe, is the
case with Sharpe’s Ammonites wiltonensis ; the type of this species
was collected by Mr. W. Cunnington from the Chalk Rock of
Oldbury Hill, 73 miles E.S.E. of Warminster, and is now in the
British Museum ; the form of the shell, as well as its ornamentation
and suture-line, agrees perfectly with Scaphites Gentz.

By some authors this species has been recorded from the Chalk
Rock as S. equalis—a form which is not found in the Turonian.

In the Survey Memoir on Cambridge,’ Scaphites equalis(?) is
‘recorded from the zone of Holaster planus of Ickleton: the specimen
ds now in the Jermyn Street Museum, and is, I believe, referable to
S. Geinitzi, but it is not sufficiently perfect to be determined with
certainty. Whitaker* records Scaphites sp. from the Upper Chalk
-of Marlow, but the specimen has apparently been lost.

Affinities —Scaphites obliquus, Sowerby, from the Cenomanian, is
allied to the species under consideration, but differs from it in being
‘thicker and in having the tubercles indistinct or faintly marked.

S. equalis, Sowerby, from the Cenomanian, is also a thicker form,
especially in the hamus, the outer border of which is less rounded
than in S. Geinitzi, and the tubercles are costzform.

In S. inflatus, Romer, from the Senonian (zone of S. benodosus)
of Westphalia, the row of tubercles is found on the involute as well as"
-on the evolute part, and extends to the aperture. The hamus is rela-
tively shorter than in S. Geenitzi, and the suture-line more divided.

In S. hippocrepis (Dekay) = Cuviert, Morton, from the argillo-
ferruginous sand of the Chesapeake and Delaware Canal, the row of
‘tubercles is similar to that in S. Geinitzi, but extends to the
-aperture.

Distribution.—England: Chalk Rock of Dover, Winchester, Old-
‘borough Castle, Cuckhamsley, Prince’s Risborough, Boxmoor, Luton
cutting, Hitchin, and Underwood Hall near Dullingham. Perhaps
-also in the zone of Holaster planus and in the Upper Chalk (? zone of
Micr. cor-testudinarium). France: zone of Epiaster brevis at Fontaine-
‘les-Vervins, zone of Mier. breviporus of Cambrai, zones of Hol.
planus and Hp. brevis east of the Paris basin, zone of Spondylus
truncatus of the Loir-et-Cher, and ‘Craie de Villedieu.’ North-western
Germany : common in the zone of Heteroceras Reussianum throughout
‘North-western Germany, rare in the zones of Inoc. Cuvieri and
Inoc. Brongniarti. Saxony: Planer-Kalk of Strehlen and Weinbohla,
-and Scaphites-beds of Zatzschke. Silesia: Scaphites-beds of Oppeln.
Bohemia: through the Turonian and in the Priesen Beds; found
at Priesen, Teplitz, Bohmisch-Kamnitz, Waldeck, etc. Bavaria:
Kagerhoh Beds of the Buchleitner Bruch, near Passau.

eee and Jukes-Browne, ‘Geol. Neighbourhood of Cambridge ’ (1881),
yp. 65.
2 *Geol, London, ete.’ vol. i. (1889) p. 81.
@2

84. MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

Genus Crioceras, Leveillé, 1836.

CRIOCERAS ELLIPTICUM (Mantell), 1822. (PI. III. figs. 8-10.)

1822. Hamites ellipticus, G. A. Mantell, ‘ Foss. S. Downs,’ p. 122, pl. xxiii. f. 9 5:
1840. H. B. Geinitz, ‘ Charakt. d. Schichten u. Petrefacten d. sachsischen Kreidegeb. 3
Heft 2, p.41; 1841. F. A. Romer, ‘ Verstein. d. norddeutsch. Kreidegeb.’ p. 93,,

pl xiv. £15; 1843. H. B. Geinitz, ‘ Die Verstein. von Kieslingswalda,’ p. 9, pl. 1. f. 7;
1846. AB. ’Geinitz, ‘ Grundr. der Verstein.’ p. 304; 1852. C. G. Giebel, ‘Fauna der
Vorwelt,’ vol. iii. p. 302 ; 1854. ? J. Morris, ‘ Cat. Brit. Foss.’ 2nd ed. p. 305.

1822. Hamites alternatus, G.A. Mantell, ‘ Foss. S. Downs,’ p. 122, pl. xxii. f. 10, 11;.
1840. H. B. Geinitz, ‘ Charakt. d. Schichten u. Petrefacten d. sichsischen Kreidegeb.
Heft 2, p. 41 ; 1841. F. A. Romer, ‘ Verstein. d. porddeutsch. Kreidegeb.’ p. 93.

1842. Hamites alternans, H. B. Geinitz, ‘Charakt. d. Schichten u. Petref. d.
sichsischen-bohm. Kreidegeb.’ Heft 3, p. 68, pl. xvii. f. 36; 1861. F. J. Pictet and.
J. Campiche, ‘ Foss. des Terr. Crét. de "Ste. -Croix,’ Pal. Suisse, ser. 3, pt. li. p. 938.

1850. Hamites angustus, J. de C. Sowerby, in F. Dixon’s ‘Geology of Sussex,’
p. 346 (p. 385 of 2nd ed. 1878), pl. xxix. f. 12; 1876. C. Barrois, ‘ Recherches sur le
Terr. Crét. Sup. de I’ Angleterre et de l Irlande, p . 29 (footnote 4).

1850. Ancyloceras ellipticus, A. @Orbigny, ‘ Prd, de Paléont.’ vol. ii. p. 147;
1861. F. J. Pictet and G. Campiche, ‘Foss. du Terr. Crét. de Ste.-Croix,’ Pal.
Suisse, ser. 3, pt. ii. p. 41.

1850. Hamites Geinitzii, A. V POrbigny, ‘Prodr. de Paléont.’ vol. ii. p. 215 ; 1872.
? A. Fritsch and U. Schlénbach, ‘ Ceph. bohm. Kreideformat.’ p. 46, pl. xvi. f. 16.

1852. Hamites armatus, C. G. Giebel, ‘ Fauna der Vorwelt,’ vol. ili. p. 297 (partim) ;
1854. var., J. Morris, ‘Cat. Brit. Foss.’ ed. 2, p. 305.

1861. Anisoceras alternatus, F. J. Pictet and oe Campiche, ‘ Foss. des Terr. Crét.
de Ste.-Croix,’ Pal. Suisse, ser. 3, pt. ii. p. 71, p

1872. Crioceras ellipticum, C. Schlatter, 2 Goole oberen deutsch. Kreide,’ p. 100,
pioxxx. t..11, 12, pl. xii. f. 1, 2.

1872. PP Hamites cf. angustus, C. Schliiter, ibid. p. 106, pl. xxxii. f. 6, 7.

1874. Hamites ellipticum, H. B. Geinitz, * ‘Das Elbthalgebirge in Sachsen ’ (Palae-
ontographica, vol. xx.), pt. il. p. 194, pl. xxxv. f. 138-15, ? 16.

Description.—Shell elliptical in section, ornamented with strong
ribs, which become less prominent on the inner margin, and are
slightly flexuous in the older specimens. Lach rib bears a pair of
tubercles, one on each side of the siphonal line; the pairs are
alternately large and small, but the relative size varies in different
specimens, in some the two sets are of nearly equal size, in others
one set is very much smaller ; occasionally the alternation in size is
somewhat irregular.

Suture-line: siphonal lobe small, superior-lateral lobe deep, bifid,
not quite symmetrical, inferior-lateral lobe similar to the last, but
not so deep, internal lobe smaller, not quite symmetrical; saddles
much broader than the lobes, siphonal saddle bipartite, larger than
the superior-lateral saddle, inferior-lateral saddle of about the same
width but not so deep as the superior-lateral.

Remarks.—The type of Mantell’s Hamites ellipticus (fig. 9) is in
the British Museum, but that of Hamites alternatus cannot be
traced. Both of Mantell’s specimens came from the Chalk Marl of
Middleham.

Distribution —England: Lower and Middle Chalk. Chalk Rock
of Winchester, Cuckhamsley, Luton cutting, Hitchin, and Under-
wood Hall near Dullingham. france: zone of Terebratulina gracilis
east of the Paris basin. North-western Germany: confined to the
zone of Het. Reussianum, found at Heiningen, Windmihlebergen
near Salzgitter, Neue Wallmoden, etc. Saxony: Planer-Kalk of
Strehlen and Weinbohla.

Vol. 52.] OF THE CHALK ROCK. 85

Ill. Class GASTEROPODA.
Order Prosobranchia.

Family Fissurellide, Risso.
Genus Emarernvuta, Lamarck, 1801.

Emareinvia Sancta-CatHarin”, Passy.

1832. Emarginula Sancte-Catharine, Ae Passy, ° Descr. Géol. de la Seine-In-
férieure,’ p. 335, pl. xvi. f.1; 1843. A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. ii.
p. 395, pl. cexxxv. f. 4-6 ; 1877. J.S. Gardner, Quart. Journ. Geol. Soc. vol. xxxiii.
p. 198, pl. vil. f. 21, 22.

1850. Emarginula affinis, J. de C. Sowerby, in F. Dixon’s ‘ Geol. Sussex,’ p. 348
{p. 383 of ed. 2), pl. xxvii. f. 20, 25; 1854. J. Morris, “Cat. Brit. Foss.’ ed. 2, p. 246 ;
1877. J. S. Gardner, Quart. Journ. Geol. Soc. vol. xxxiii. p. 200.

Affinities. —This is a species with cancellated ornament produced
by longitudinal ribs of two sizes crossed by transverse ribs. It is
distinguished from H. unicostata, Gardner (Upper Chalk of Norwich),
by its more elevated form; from Z£. loculata, de Ryckholt (Ceno-
manian of Tournay and Montignies-sur-Roc), by possessing ribs of
two sizes; and from #. Desori, Pictet and Campiche (Upper Gault
of Ste.-Croix), by having more numerous ribs.

Remarks.—The specimens from the Chalk Rock agree in every
respect with Sowerby’s £. affinis, and this, as suggested by
Mr. Gardner, is, 1 think, without doubt identical with EL. Sancte-
Catharine.

The figure given by Passy is very unsatisfactory, and is not
accompanied by a description of any kind, so that one is almost
obliged to rely on d’Orbigny’s figures and diagnosis. The type
comes from the Cenomanian of Rouen.

I have not been able to find Sowerby’s type; the specimen
figured by Gardner, which comes from the Chloritic Marl of White
Nore, is in the Museum of Practical Geology, No. 35%.

Localities.—England: Chloritic Marl of Wiltshire and Dorset ;
Lower Chalk of Kent and Sussex; Chalk Rock of Cuckhamsley and
Luton cutting. France: Cenomanian of Rouen,

EMARGINULA aff. DivisrensIs, Gardner.

1877. E. divisiensis, J. S. Gardner, Quart. Journ. Geol. Soc. vol. xxxiii. p. 198,
pl. viii. f. 19, 20.

A cast from Cuckhamsley in the Montagu Smith collection is
allied to this species, but is hardly sufficiently well-preserved for
definite determination ; it is more ovate than FH. divisiensis. The
type of E. divisiensis comes from the Upper Greensand of Devizes,
and is preserved in the British Museum.

EMARGINULA sp.

A single specimen from the Chalk Rock of Cuckhamsley is
apparently new. It has a subcircular form, with a much elevated
and nearly central apex; it is in the form of a cast, and the
ornamentation is unknown.

86 MR, H. WOODS ON THE MOLLUSCA [Feb. 1896,

Family Pleurotomariide, d’Orbigny.
Genus Prevroromaria, Defrance, 1821.
Sub-genus Lrepromarra, Kudes-Deslongchamps, 1865.

PLEVROTOMARIA (LEPTOMARIA) PERSPECTIVA (Mantell), (Pl. III.
figs. 13, 14, & Pl. LV. fig. 1.)

1822. Cirrus perspectivus,.G. A. Mantell, ‘Foss. S. Downs,’ p. 194, pl. xviii.
f. 12, 21; 1823. J. Sowerby, ‘ Min. Conch.’ vol. v. p. 35, pl. eccexxviti. f. 1, 2.

1822. Trochus linearis, Mantell, ibid. p. 110, pl. xviii. f. 16, 17.
_ 1822. Cirrus depressus, Mantell, ibid. p. 195, pl. xviii. f. 18, 22; 1823. Sowerby,
‘Min. Conch.’ vol. v. p. 38, pl. cecexxviii. f. 3.

1835. Pleurotomaria distincta?, F. Dujardin, Mém. Soc. géol. de France, vol. ii.
p. 231, pl. xvii. f. 6; 1840. A. Goldfuss, ‘ Petref. Germ.’ pt. 3, p. 75, pl. clxxxvii. f. 1 5.
1841. F. A. Romer, ‘ Die Verstein. des norddeutsch. Kreidegeb.’ p. 82 (partim).

1840. Trochus linearis, H. B. Geinitz, ‘Char. d. Schicht. u. Petref. des sachs..
Kreidegeb.’ Heft 2, p. 46, pl. xiii. f. 6, 8, pl. xv. f. 18, 19.

1840. Pleurotomaria velata, A. Goldfuss, ‘ Petref. Germ.’ p. 76, pl. clxxxvii. f. 2.

1840. Pleurotomaria granulifera, Goldfuss, ibid. p. 76, pl. clxxxvii. f. 3.

1842. Pleurotomaria perspectiva, A. d’Orbigny, ‘ Pal. Frang. Terr. Crét.’ vol. it.
p- 255, pl. excvi. f. 1-5 ; 1850. J. de C. Sowerby, in F. Dixon’s ‘Geol. Sussex,’ p. 349
(p. 384, ed. 2), pl. xxvii. f. 27; 1854. J. Morris, ‘Cat. Brit. Foss.’ ed. 2, p. 271; 1863.
F. J. Pictet and G. Campiche, ‘ Foss. Terr. Crét. Ste.-Croix,’ ser. 3, pt. 11., Pal. Suisse,
p. 454; 1874. H. B. Geinitz, ‘Das Elbthalgeb. in Sachsen’ (Palaeontographica,
vol. xx.), part ii. p. 166 (? pl. xxix. f.11); 1889. A. Fritsch, ‘ Stud. im Geb. der bohm..
_Kreidet. 1V. Die Teplitzer Schichten,’ p. 74, £.49.

1845. Pleurotomaria linearis, A. KE. Reuss, ‘Die Verstein. bbhm. Kreideformat.’
p. 47; 1850. H. B. Geinitz, ‘Das Quadersandst. oder Kreidegeb. in Deutschland,”
p. 134 (partim) ; 1870. F. A. Romer, ‘Geol. von Oberschlesien,’ p. 318, pl. xxxv. f. 1,
2; 1874. H. B. Geinitz, ‘ Das Elbthalgeb. in Sachsen ’ (Palaeontographica, vol. xx.),
pt. 1. p. 165, pl. xxix. f. 10; 1883. A. Fritsch, ‘Stud. im Gebiete der bohm. Kreide-
format. III. Die Iserschichten,’ p. 95, f. 57; 1889. Fritsch, ibid. ‘IV. Die Teplitzer
Schichten,’ p. 74, f. 48. ,

1846. Plewrotomaria (Trochus) linearis, H. B. Geinitz, ‘ Grundriss der Verstein.”
p. 355, pl. xv. f. 1.

Description.—Shell heliciform, depressed, composed of 7 whorls,.
which are obtusely angular, the parts above and below the angle
being flat or nearly flat. Base of last whorl rounded. Sinus-band
narrow, prominent, smooth (apparently), placed at the angle,
slightly posterior to the middle of the whorl. Umbilicus large,
deep. Sutures shallow. Ornamentation consisting of numerous
longitudinal ribs, which, on the earlier whorls, are markedly
granular, the granules having a transverse arrangement also.
Growth-lines curving backwards to the sinus-band are seen on
some of the later whorls. Base with numerous close-set longi-
tudinal (spiral) ribs. Aperture broad, outer lip rounded. Size of.
a large specimen: length 44 mm., width 82 mm. '

Remarks.—The appearance of this species varies considerably,
according to the state of preservation and the age of the specimens.
The granular character of the ornamentation is seen best in young
individuals; on the later whorls of large specimens the ribs are
often nearly smooth, but this is probably due to abrasion. When
the shell is much worn, the surface appears to be striated rather
than ribbed. The sides of the spire are convex, except in young,

Vol. 52.] OF THE CHALK ROCK. 87

forms, in which, in the apical part at any rate, they are flat or
concave.

P. perspectwa is almost the only gasteropod of the Chalk Rock in
which the shell is generally preserved. It is also one of the com-
monest species; in the Woodwardian Museum there are no less
than 65 specimens from a single locality—namely, Cuckhamsley.

Mantell does not give any exact locality for his Cirrus perspectivus,
but simply states ‘Upper and Lower Chalk of the South Downs;
rare in the latter deposit.’ The forms described by Mantell as
Trochus linearis (from the Chalk Marl of Hamsey) and Cirrus
depressus (from the Upper Chalk of Lewes) have been considered by
d’Orbigny, Morris, and others to be identical with perspectivus: the
apparent differences being due merely to conditions of preservation.
The examination of a large series of specimens which I have made
confirms this view. Geinitz and Fritsch, however, regard P. per-
spectiva and P. linearis as distinct species.

The types of Mantell’s Cirrus perspectivus (except fig. 12), C. de-
pressus, and T'rochus linearis are preserved in the British Museum ;
so also are the originals of Sowerby’s figures of Cirrus perspectivus
and C. depressus, and of Dixon’s figure of P. perspectiva. Both
Mantell’s and Sowerby’s specimens are badly preserved, and hence
it is very difficult to make out the real characters of the species.

Affinities.—P. neocomiensis of d’Orbigny, from the Lower Cre-
taceous of France, is distinguished from P. perspectiwa by the
smaller spiral angle, the ornamentation consisting of striz instead
‘of ribs, and by the sinus-band being sunk.

The absence of longitudinal ribs and the presence of strong
growth-lines on the base of the shell separate P. plauensis, Geinitz
(Cenomanian of Plauen, etc.), from this species.

P. seriato-granulata, Goldfuss, from the Turonian of Saxony and
Bohemia, is near to P. perspectiva, but the shell is more depressed
and the base of the whorl is angular.

Barrois’s P. Merceyi, from the zone of Micr. cor-anguinum of
Lezennes, etc., is related to P. perspectwa, but the figure given by
that author is not sufficiently clear to allow of any detailed com-
parison being made.

Distribution.—England: Chalk Marl of Folkestone and Hamsey ;
Lower Chalk of the Isle of Wight; Upper Chalk of Norwich,
Northfleet, and Lewes. Chalk Rock of Dover, Winchester, Old-
borough Castle, Cuckhamsley, Aston Rowtant, Prince’s Risborough,
Luton, Hitchin, Underwood Hall near Dullingham, and Carleton
Grange. Jreland: Hibernian Greensand. France: Cenomanian of
Rouen. Westphalia: Senonian of Haldem, Coesfeld, and Lemforde.
Sawony: Pliner-Kalk of Strehlen and Weinbéhla, rarely in older
beds. Silesia: Scaphites-beds of Oppeln. Bohemia: Iser, Teplitz,

and Priesen Beds. Bavaria: Regensburg Beds of Galgenburg,
-Reinhausen, ete.

1 Ann. Soc. géol. du Nord, vol. vi. (1879) p. 450, pl. xii. f. 2a, 5.

88 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

Family Trochide, Adams.
Genus Trocuvs, Linneeus, 1758.
Trocuvs Scuiirert, sp. nov. (PI. III. figs. 11 & 12.)

Deseription.—Shell conical, without an umbilicus. Whorls flat,
six (or seven) in number, with a deep depression at the suture:
surface ornamented with fine longitudinal rows of tubercles, the
marginal rows being a little larger than the three inner rows.
Tubercles connected by faintly-marked longitudinal and transverse
ribs, the latter crossing the whorls obliquely and parallel to the
margin of the aperture. In the sutural depression just above the
middle is a row of smaller tubercles. The spire is about 4ths the
entire length of the shell. Base a little convex, with eight or nine
longitudinal (spiral) ribs bearing close-set tubercles. Aperture not
well seen.

Affinities. —The ornamentation of this species is very similar to
that in 7. amatus, d’Orbigny* (from Haldem, Strehlen, etc.), but
in that form the whorls are rounded.

Distribution.—Chalk Rock of Dover, Oldborough Castle, Cuck-
hamsley, Luton cutting, Hitchin, Reed near Royston, and Under-
wood Hall near Dullingham.

TROCHUS BEROCSCIRENSE, Sp. nov. (PI. IV. figs. 2-4.)

Description.—Shell conical, composed of six flat whorls, spiral
angle 58°; spire about 3ths the entire length; sutures deep.
Whorls ornamented with fine longitudinal rows of tubercles, the
top and two bottom rows being much larger than the others. Base
a little convex, with a depression at the centre; ornamented with
curved growth-lines and a row of small tubercles near the periphery.
Aperture sub-rhomboidal.

Affinities.—This species resembles 7’. Engelhardti, Geinitz,? from
the Pliner-Kalk of Strehlen ; but in that form the sutures are not
so deep, and the ornamentation consists of a row of large tubercles
at the top and at the bottom of each whorl, with three or four
smaller rows between.

Remarks.—I.have only seen five specimens of this species, all of
which are in the Montagu Smith Collection.

Disiribution.—Chalk Rock of Cuckhamsley.

Family Turbinide, Chenu. ,
Genus Turso, Linnzus, 1758.
Turso Grrnirzi, sp. nov. (Pl. IV. figs. 5-8.)

Description.—Shell turbinate, turrited, sutures deep, spiral angle

1 «Prodr. de Pal.’ vol. ii. (1850) p. 224. For figure see Goldfuss, ‘ Petref.
Deutschl.’ pt. 11. (1840) p. 58, pl. elxxxi. f. 7, and Geinitz, ‘Das Elbthalgeb. in
Sachsen’ (Palaeontographica, vol. xx.), pt. ii. (1874) p. 164, pl. xxix. f. 7.

2 ‘Das Elbthalgeb. in Sachsen’ (Palaeontographica, vol. xx.), pt. ii. (1874)
p. 163, pl. xxix. f. 5,

Vol. 52.' OF THE CHALK ROCK. 89

about 39°. Whorls 4 or 5 in number, convex, rather angular, the
posterior part of each is flat and ornamented with four longitudinal
rows of tubercles; at the keel is a row of large and prominent
tubercles, anterior to which is a nearly flat band with faint ribbing,
and then three or four more longitudinal rows of tubercles. Base
convex, rounded, with numerous close-set longitudinal (spiral) ribs
bearing small tubercles. Umbilicus of moderate size. Aperture
sub-circular.

Affinities—The general form of the shell is similar to fig. 5 of
Roémer’s* Delphinula tricarimata, but in that species there is
apparently only one row of tubercles ; the other specimens figured
by the same author (figs. 3, 4, and 6) are quite unlike our species.

Portlock * in 1848 gave under the name of Turbo? bicarinatus
[Sowerby MS.] a brief description, without figures, of a very
imperfect specimen from the White Limestone of Tamlaght, co.
Derry, which is probably allied to 7. Geinitzi. The name,
however, was already occupied, and was changed by Tate? in 1865
to Thomsoni, he at the same time referring it to the genus Pleuroto-
maria. The type is preserved in the Museum of Practical Geology,
Jermyn Street, no. 22. It consists of three whorls; over a con-
siderable part of the specimen the inner layer only of the shell is
present ; this gives some idea of the original form of the whorls,
justifying Portlock’s statement that they have ‘two slight parallel,
rather distant ridges winding up below their middle.’ Adjoining
the suture of the last preserved whorl is a very small fragment of
the outer layer of the shell showing the ornamentation: this is
much less coarse than in the Chalk Rock species. I have not been
able to obtain another specimen from the White Limestone; and
until this is done the characters of the Irish species and its relation
to 7’. Geinitzi cannot be made out.

Distribution.—Chalk Rock of Dover, Cuckhamsley, Hitchin, and

Luton.

Turso gemmatus, Sowerby. (PI. IV. figs. 9 & 10.)

1850. Turbo gemmatus, J. de C. Sowerby, in F. Dixon’s ‘Geol. Sussex,’ p. 349
(p. 385, ed. 2, 1878), pl. xxvil. f. 26, 33; 1854. J. Morris, ‘ Cat. Brit. Foss.’ ed. 2,
283

p. 283.

1878. Turbo Heberti, C. Barrois and J. de Guerne, Ann. Soc. géol. du Nord,
vol. v. p. 58, pl. ii. f. 11; 1887. A. Peron, ‘Notes pour servir 4 VHist. du Terr. de
Craie,’ Bull. Soc. Sci. hist. et nat. de ’Yonne, ser. 3, vol. xii. p. 142, pl. i. f. 5-8.

[Non T. gemmatus, Lycett, Quart. Journ. Geol. Soc. vol. xiv. (1853) p. 342,
pl. xiv. f. 7, from the Inferior Oolite. |

Description.—Shell conical, slightly longer than broad, composed
of six whorls which are a little convex, and ornamented with
several (generally seven) longitudinal ribs bearing granules—those
on the upper rib being larger than the others. Sutures well marked.
Margin of the last whorl rounded ; base slightly convex ; umbilicus
large with a ridged margin. Aperture subquadrangular or rounded.

1 F. A. Romer, ‘Die Verstein. des norddeutsch. Kreidegeb.’ 1841, p. 81,
pl. xii. f. 3-6.

2 «Report on the Geology of Londonderry, etc.’ p. 421.

3 Quart. Journ. Geol. Soc. vol. xxi. p. 37.

90 MR. H, WOODS ON THE MOLLUSCA [Feb. 1896,

Remarks.—Sowerby’s types, which come from the Lower Chalk
of Kent, are in the British Museum. Barrois states that 7’. Heberta
differs from TZ. gemmatus by the ridges on the margin of the
umbilicus, but in the specimens figured by Sowerby the umbilicus
cannot be seen; in examples from the Chalk Rock, however, the
ridges are present, so that there seems to be no reason for sepa-
rating 7’. Heberti from the English species.

T. Guerangeri, d’Orbigny, can be distinguished from this species
by the more angular whorls, whilst in 7’. Goupilianus of the same
author the whorls are much more convex.

Distribution. England ; Lower Chalk of Kent and Sussex (fide
Morris and Dixon). Chalk Rock of Dover, Winchester, Oldborough
Castle, Cuckhamsley, Luton cutting, Hitchin, Reed near Royston,
Barkway, and Underwood Hall near Dullingham. Northern France:
Cenomanian of Ste. Parres-aux-Tertres, near Troyes, and Vitry-le-
Francois; zone of Bel. plenus at Neuville-au-Pont, Charontelles
(Marne), etc.; Turonian of Villecien, near Joigny (Yonne).

TURBO GEMMATUS, Var. a.

There are several specimens in the Montagu Smith Collection
which agree with 7’. gemmatus, except in being much longer; the
shell is almost twice as long as broad and consists of 9 whorls. It
will, I think, be best to regard this form simply as a variety of
T. gemmatus.

Distribution.—Chalk Rock of Cuckhamsley.

Family Capulide, Fleming.

Genus Crepipuna, Lamarck, 1799.
CREPIDULA, sp.

Remarks.—Some specimens of a Crepidula closely resemble C.
Cooksonic, Seeley,: from the Cambridge Greensand (= Calypireea
Sancte-Crucis, Pictet and Campiche, from the Upper Gault of Ste.-
Croix), except that the internal plate is relatively smaller. There
is a good deal of variation in the form of the shell, some examples
being much elevated, others depressed; in the former the cast of
the septum has the appearance of an inverted U, but in the latter
the limbs of the U diverge widely.

All the specimens are in the form of internal casts, and con-
sequently I refrain from giving a specific name.

Distribution.—Chalk Rock of Cuckhamsley (Montagu Smith Col-
lection).

1 H. G. Seeley, Ann. Mag. Nat. Hist. ser. 3, vol. vii. (1861) p. 291, pl. xi.
f.18. See also A. J. Jukes-Browne, Quart. Journ. Geol. Soc. vol. xxxi. (1875)
p. 294; J. S. Gardner, zbid. vol. xxxiii. (1877) p. 201, and Geol. Mag. 1877,
pl. xvi. f. 19, p.556. For C. Sancte-Crucis, see Pictet and Campiche, ‘ Foss.
du Terr. Crét. de Ste.-Croix,’ 1864, p. 696, pl. xcvii. figs. 5-8. Mr. Gardner
considers that these species, and perhaps also Galericulus altus, Seeley, are
identical with Crepidula gaultina, Buvignier. :

Vol. 52.] OF THE CHALK ROCK. 91

Family Naticidz, Guilding.
Genus Natrca, Adanson, 1757.

Natica (Naticruva ') vutearts, Reuss.

1840. Littorina rotundata, H. B. Geinitz (non Sowerby sp.), ‘Char. der Schichten
und Petrefacten des sachs. Kreidegeb.’ Heft 2, p. 45, pl. xiii. f. 7, pl. xv. f. 16
(? pl. xiv. f. 10, pl. xv. f. 17).

1844, Natica vulgaris, A. E. Reuss, ‘Die Kreidegeb. des westlichen Bohmens,’
vol. ii. p. 209 ; ? 1843. H. B. Geinitz, ‘ Die Verstein. von Kieslingswalda,’ p, 10, pl. i.
f. 21 (non figs. 22-23) ; 1845. A. E. Reuss, ‘ Die Verstein. der bohm. Kreideformat.’
p- 50, pl. x. f. 22; 1846. H. B. Geinitz, ‘Grundriss der Verstein.’ p. 339, pl. xv. f. 18 ;
1850. id. ‘Das Quadersandst. oder Kreidegeb. in Deutschland,’ p. 128 (partim) ;
1889. A. Fritsch, ‘Stud. im Geb. der béhm. Kreidef. IV. Die Teplitzer Schichten,’
p- 73; 1893. Fritsch, ibid. ‘ V. Die Priesener Schichten,’ p. 82, fig. 67.

1875. Natica lamellosa, H. B. Geinitz, ‘ Das Elbthalgebirge in Sachsen’ (Palaeonto-
graphica, vol. xx.), pt. i. p. 243, pl. liv. f. 17; 1877. A. Fritsch, ‘Stud. im Gebiete
der bohm. Kreideformat. II. Die Weissenberger und Malnitzer Schichten,’ p. 105,
woodcut 43 ; 1883. Fritsch, ibid. ‘ III. Die Iserschichten,’ p. 94.

Description.—Shell a little longer than wide. Spire more than
half the last whorl in length. Whorls 5, rounded and very convex,
especially the last. Surface with lines of growth and also distant
faintly-marked rings (varices) ; the lines of growth are crossed by
fine longitudinal striz. Umbilicus rather small. Aperture elongate-
oval,

Affinities. —Geinitz considers this species to be identical with JV.
lamellosa, of Romer,’ from Kieslingswalda; but Fritsch apparently
regards it as distinct. This, however, is a point which can hardly
be settled by the aid of Romer’s figure.

NV. cretacea, Goldfuss,* from the Aachen Greensand, differs from
NV. vulgaris in having a much wider aperture.

NV. exaltata, Goldfuss,* also from the Aachen Greensand, is dis-
tinguished by the greater length of the shell.

NV. lyrata, Sowerby,’ from Gosau, is allied to N.. vulgaris, but
possesses a shorter spire.

Stoliczka ° considers that Huspira pagoda (Forbes), from the
Arrialoor Group, is closely related to this species, but the whorls in
that form are more numerous and the spire more acute.

Remarks.—1 have seen 23 examples of this species from the
Chalk Rock, but most of them are in the condition of casts; a few
show portions of the shell with the lines of growth and longitudinal
strie. The varices are indicated on the casts by slight depressions.

The type figured by Reuss came from the Pliner-Mergel of
Priesen, Bohemia.

1 Naticina of Guilding, 1834.

2 ‘Die Verstein. des norddeutsch. Kreidegeb.’ (1841) p. 83, pl. xii. f. 13.

° ‘ Petref. Germ.’ (1840) p. 119, pl. excix, f. 12. See also Binkhorst, ‘Mon.
des Gast. et Céph. de la Craie Supér. du Limbourg’ (1861), p. 21.

4 Ibid. (1840) p. 111, pl. excix. f. 12.

° Sowerby, Trans. Geol. Soc. ser. 2, vol. iii. (1835) pl. xxxviii. f. 11. See

also d’Orbigny, ‘ Terr. Crét.’ vol. ii. (1842) p. 161, pl. clxxii. f. 5; Zekeli, ‘ Die

Gastr. d. Gosaugeb.’ Abh. d. k. k. geol. Reichsanst. vol. i. (1852) p. 46, pl. viii-
f. 5; and Stoliczka, ‘Cret. Fauna S. India,’ vol. ii. (1868) p. 303, pl. xxii. f. 2
(Palzont. Indica). .8 Op, cit. p. 301.

92 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

Distribution.—England : Chalk Rock of Cuckhamsley, and Under-
wood Hall near Dullingham ; Saxony: Pliner-Kalk of Strehlen,
Planer-Mergel of Walkmiihle near Pirna, ete.; Bohemia: through-
out the Turonian and in the Priesen and Korycan Beds of numerous
localities; Bavaria: Grossberg Beds.

Family Cerithiide (Férussac), Menke.

Genus Crrtratum, Adanson, 1757.
CERITHIUM CUCKHAMSLIENSE, sp.nov. (Pl. IV. fig. 11.)

Description.—Shell elongate, composed of about twelve whorls.
Spiral angle 21°. Whorls flat or very slightly convex, with a
narrow anterior part sloping steeply to the suture; surface smooth
or with growth-lines. Aperture imperfectly known. Length (ap-
proximative) 38 mm., width 14 mm.

Affinities.—This species resembles C. eacavatum of Brongniart,’
from the Gault, but in that form the whorls are more concave, and
the sutures are bordered by two ridges.

Distribution.—Chalk Rock of Cuckhamsley and Luton.

Crriruium SaunpeErs!, sp. nov. (Pl. IV. fig. 12.)

Description.—Shell elongate, turrited, composed of twelve whorls.
Spiral angle 18°-19°. Whorls nearly flat; sutures fairly distinct.
Ornamentation consists of round tubercles having a transverse and
longitudinal arrangement ; there are four longitudinal rows of equal
size, and about sixteen transverse rows on each whorl. The longi-
tudinal rows are separated by less than the diameter of a tubercle;
the transverse are more distant. Between the longitudinal rows
there are three or four fine ribs. Immediately posterior to the suture
is a fifth row of smaller and more numerous tubercles. Base with
spiral strie. Aperture not well seen. Length (approximative)
37 mm., width 11 mm.

Affinities—This species is easily distinguished from C. pustu-
losum, Sowerby * (Gosau Beds), by its smaller spiral angle and fewer
tubercles. C. pustulosum of d’Orbigny * (non Sowerby) is near to
C. Saundersi, but the sutures are much deeper. |

C. pseudoclathratum, d’Orbigny,* differs from this by its greater
sutural angle, and by the posterior rows of tubercles being smaller
than the anterior.

Nstribution.—Chalk Rock of Cuckhamsley and Hitchin.

1 ¢ Envir. de Paris,’ in Cuvier’s ‘ Oss. Foss.’ vol. ii. (1822) p. 614, pl. ix. f.10;
dOrbigny, ‘Pal. Franc. Terr. Crét.’ vol. ii. (1843) p. 371, pl. ccexxx. f. 12;
Picetet and Roux, ‘ Moll. Foss. d. Grés Verts des Env. de Genéve’ (1849), p. 279,
pl. xxvii. f. 7 a-c.

_ ? Sowerby, Trans. Geol. Soe. ser. 2, vol. iii. (1835) pl. xxxix. f. 19. See also
Zekeli, ‘Die Gasterop. d. Gosaugeb.’ Abh. der k. k. geol. Reichsanst. vol. i.
(1852) p. 100, pl. xix. f. 4,5.

° «Paléont. Franc. Terr. Crét.’ vol. ii. (1848) p. 381, pl. cexxxiii. f. 4.

* Geinitz, ‘Das Elbthalgeb. in Sachsen ’ (Palaeontographica, vol. xx.), pt. ii.
(1874) p.175, pl. xxxi. f. 5.

Vol. 52.| OF THE CHALK ROCK. 93

Family Aporrhaide, Philippi.
Genus AporRHAIS, Da Costa, 1778.

Subgenus LispoprstHes, White, 1875.

AporRHAIs (LispopEstHES) Manretii, Gardner.

1822. Rostellaria Parkinsoni, G. A. Mantell, ‘ Foss. S. Downs,’ p. 108, pl. xviii.
f. 1, 2, 4-6, 10.

1850. Aporrhais stenopterus, F. Dixon, ‘Geol. Sussex,’ p. 358 (p. 386, ed. 2),
pl. xxvii. f. 31, 36; 1854. J. Morris, “Cat. Brit. Foss.’ ed. 2, p. 235.

1867. Aporrhais (Perissoptera) Parkinsoni, R. Tate, ‘Geol. & Nat. Hist. Repert.’
vol. i. p. 99.

1875. Aporrhais Mantelli, J. S. Gardner, Geol. Mag. dec. 2, vol. ii. p. 202, pl. vi.

f. 8, 9.

Remarks.—The originals of Mantell’s figures 1, 5, 6, and 10 are
in the British Museum. The specimens from the Chalk Rock are
in the form of casts only.

Distribution—Grey Chalk of Dover, Chalk Marl of Hamsey.
Chalk Rock of Cuckhamsley, and Luton cutting.

APORRHAIS, Sp.

Another species occurs in the Chalk Rock of Cuckhamsley
(Montagu Smith Collection), but is not sufficiently well represented
for determination. The spiral angle is about 20°. The whorls are
angular and provided with an almost median keel; midway between
this and the anterior suture is a rib. No other ornamentation is
visible.

Family Lampusidz, Newton.

Genus Lampusia, Schumacher, 1817.

Lampusia?, sp. (Pl. IV. figs. 13, 14.)

There are five specimens in the Montagu Smith Collection which
apparently belong to this genus—three are internal casts, one is an
external cast, and one has a small portion of the shell preserved.
The shell consists of five or six rather convex whorls, each with
about twelve prominent transverse ridges, and with numerous
longitudinal ribs of two sizes. The casts show the crenulation of
the outer lip. Spiral angle about 30°.

Order Opisthobranchia.
Family Ringiculidz, Meek.

Genus Avetiana, d Orbigny, 1842 (sensu stricto).

AVELLANA, Sp., cf. Humpoxpri, Muller. (Pl. IV. fig. 15.)

1851. Avellana Humboldti, J. Miller, ‘Mon. der Petref. der Aachener Kreide-
format.’ part ii. p. 12, pl. iii. f. 15.

1888. Cinulia Humboldti, E. Holzapfel, ‘Die Mollusken der Aachener Kreide’
(Palaeontographica, vol. xxxiv.), p. 84, pl. vi. f.19-21.

Description.—Shell globose, a little longer than broad, composed

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96 MR. H. WOODS ON THE MOLLUSCA [Feb. 1896,

of four or five whorls; outer lip thickened, with the inner margin
coarsely crenulated. Columella with two or three strong folds.
Ornamentation consisting of fine spiral grooves (about 24 on the
last whorl) with pits in the grooves. Size of an average specimen—
height 18 mm., height of last whorl 16 mm., diameter 14 mm.

Remarks.—A. Archiaciana is found in the Aachen Greensand ;
the Chalk Rock species is very near to this, but without seeing
specimens of the Aachen form I cannot be quite sure of their
identity. Most of the specimens from the Chalk Rock are in the
form of casts, but a few have part of the shell preserved; the
character of the ornamentation is seen in the wax models taken
from the external casts.

Distribution.—Chalk Rock of Winchester, Cuckhamsley, Eases
cutting, Hitchin, and Underwood Hall near Dullingham.

In addition to the species described above there are a few others
which are too imperfect for determination." The most interesting
of these is one which belongs to the Volutide or Mitridz ; it is
represented by four imperfect casts from Cuckhamsley (Montagu
Smith Collection) and one from Hitchin (coll. Mr. W. Hill). There
are three well-marked folds on the columella; the spire of the shell
was long. Length of the two last whorls 27 mm., width 10 mm.

IV. Class SCAPHOPODA.
Family Dentaliide, Gray.
Genus Drntazium, Linneus, 1758.

DENTALIUM TURONIENSE, sp. nov. (Pl. IV. figs. 16 & 17.)

Deseription.—Shell slender, elongate, tapering very gradually,
circular in section. Ornamentation consisting of twenty-five to
twenty-eight straight longitudinal ribs, crossed by smaller trans-
verse ribs. Length about 47 mm.

Affinities.—D. planicostatum, Hébert,’ from Meudon, is similar to
this species, but is distinguished by the absence of transverse ribs
and by the more rapid tapering of the shell.

Distribution.—Chalk Rock of Winchester, Cuckhamsley, and
Luton cutting.

1 Solarium has been recorded from the Chalk Rock, but I have seen no ex-
ample of this genus; the determinations were probably based on the internal

casts of Plewrotomaria. .
? Mém. Soe, géol. France, ser. 2, vol. v. (1855) p. 374, pl. xxix. f. 11.

Vol. 52.] OF THE CHALK ROCK. 97

EXPLANATION OF PLATES II.-IV.
[All specimens from the Chalk Rock. ]

Prats II.

Figs. 1, 2. Ptychoceras Smithi, sp. nov. Cuckhamsley. Montagu Smith Col-
lection, Woodwardian Museum. 1. X3. 2. Suture-line, x about 6.

3-5. Heteroceras Reussianum (dOrbigny). 3. Portion of one of the later
whorls. Luton cutting. Coll. Dr. Morison. Nat. size.

8a. Section of whorl of the same.

4. Base of later whorl. Cuckhamsley. Montagu Smith Collection. Nat.
size.

5. Suture-line of a specimen in the collection of Dr. Morison. Luton
cutting. xX 4.

6-8. Heteroceras, sp. 6. Luton cutting. Coll. Dr. Morison. Nat. size.

7a, b,c. Cuckhamsley. Montagu Smith Collection. Nat. size.

8. Suture-line of specimen, fig.7. x 4.

9-10. Baculites bohemicus, Fritsch and Schlonbach. Cuckhamsley.
Montagu Smith Collection. 9a, siphonal side ; 96, lateral; 9c, lateral ;
9d, section, nat. size. 10. Suture-line, x 4.

11. Prionocyclus Neptunt (Geinitz). Suture-line. Dunstable. Museum
of Practical Geology, Jermyn Street. Enlarged.

Puate III.

Figs. 1-4. Prionocyclus Neptuni (Geinitz). 1. Portion of last whorl. Cuck-
hamsley. Montagu Smith Collection. Nat. size.

2. Dunstable. Museum of Practical Geology. Nat. size.

3, 3a. Cuckhamsley. Montagu Smith Collection. Nat. size.

4. Section of whorl. Luton cutting. Coll. Dr. Morison. Nat. size.

5-7. Scaphites Geinitzi (d’Orbigny). Cuckhamsley. Montagu Smith
Collection. 5, 5 a, small specimen with projecting lip, nat. size;
6, 6 a, medium-size specimen, nat. size; 7, suture-line, x 5.

8-10. Crioceras ellipticum (Mantell). 8. Cuckhamsley, Montagu Smith
Collection ; 8a. Section, nat.size. 9. Luton cutting, coll. Dr. Mori-
son, nat. size; 9a. Section. 10. Suture-line, Luton cutting, Museum
of Practical Geology (J. R. 2270), x 3.

11,12. Trochus Schliteri, sp. nov. Cuckhamsley. Montagu Smith Col-
lection. 11. Drawn froma wax mould, x 14. 12. Base of an imperfect
specimen, X 1}.

13, 14. Plewrotomaria (Leptomaria) perspectiva, Mantell. Cuckhamsley.
Montagu Smith Collection. 13. Portion of a whorl seen from above,
x 2. 14. Base of a small specimen, nat. size.

Puate LY.

Fig. 1. Plewrotomaria (Leptomaria) perspectiva, Mantell. Cuckhamsley. Mon-
tagu Smith Collection. The largest specimen seen in the Chalk Rock.
Nat. size.

2-4. Trochus berocscirense, sp. nov. Cuckhamsley. Montagu Smith Col-
lection. 2. Drawn from a wax mould, X 134. 3. Outline of a specimen,
nat. size. 4. Base of a specimen, X 1}.

5-8. Turbo Geinitzi, sp.nov. Cuckhamsley. Montagu Smith Collection.
5. Nat. size; the ornamentation is taken from awax mould. 6. Speci-
men showing aperture, nat. size. 7. Base, nat. size. 8. Ornamen-
tation of base, x 23.

9,10. Turbo gemmatus, Sowerby. Cuckhamsley. Montagu Smith Col-
lection. 9, x 2; 10, x 14.

11. Cerithiwm cuckhamsliense, sp. nov. Cuckhamsley. Montagu Smith
Collection. Nat. size.

Q.J.G.8. No. 205. H

98 THE MOLLUSCA OF THE CHALK ROCK. [Feb. 1896.

Fig. 12. Cerithium Saundersi, sp.nov. Cuckhamsley. Montagu Smith Col-

lection. Nat. size. 12a. Whorl, x 14. Drawn from a wax mould.

13, 14. Lampusia(?), sp. Cuckhamsley. Montagu Smith Collection,

13. Drawn from a wax mould, x 14. 14. Internal mould, nat. size.

15. Avellana, sp. (cf. Humboldti, Miller). Ouckhamsley. Montagu
Smith Collection. Drawn from a wax mould. x 14.

16, 17. Dentalium turoniense, sp. nov. Cuckhamsley. Montagu Smith

Collection. 16. Internal mould, nat. size. 17. Ornamentation, X 4,

Discussion.

Dr. W. F. Home pointed out, in connexion with the zonal name
applied by Mr. Woods, that the horizon in question has already
received the name of the Holaster planus-zone, that fossil being
fairly abundant in England. The Author holds that the fauna is
shallow-water in character, but Trochus, Natica, and Dentalium
occur not uncommonly at over 1000 fathoms, while, with the ex-
ception of Cerithiwm and Emarginulina (the range of Crepidula
and Cinulia had not been studied by the speaker), the others have all
been found to range over 500 fathoms. Finally, the interesting com-
parison with the Lower Chalk fauna is one of the highest importance,
and will prove helpful in determining the physical conditions of
this disturbed period.

Mr. R. 8. Herrims was very glad that the Author was working
out so interesting a fauna as that of the Chalk Rock. He wished,
however, to protest against the invention of a new name for a
horizon for which a very good one was already in existence; the
_ More so as, if the proposed new name was persisted in, from what
the previous speaker had said, there would be three names to signify
the same bed.

Prof. Hut, on the other hand, thought it desirable that a less
‘insular’ name should be substituted for that of ‘ Chalk Rock,’
originally adopted by Mr. Whitaker. Now that it had been shown
by the Author of the paper and others, such as M. C. Barrois, that
this band was so rich in organic forms, and had so wide a range,
not only in the British Isles but in Europe, he considered it desirable
that some name of wider significance should be accepted, and one
which would be recognized on the Continent; and as the name
‘Zone of Holaster planus’ had been suggested by M. Barrois, he
hoped that it would be generally adopted by geologists.

Prof. H. G. Szrzzy and Mr. J. E. Marr also spoke.

Edwin Wilson Cambridge

Quart. Journ Geol.Soc Vol. LI PLT.

CHALK ROCK MOLLUSCA

NUM MU

7
——

eer ney WS
edsbebubbbbat UT LL

Quart. Journ.Geol.Soc. Vol. LIL. Pl. Ill.

Edwin Wilson. Cambridg ley.

CHALK ROCK MOLLUSCA

Quart. Journ.Geol.Soc.Vol. LIT Pl. IV.

Akaka abe

(DOONAN)

JonooANonADAD

JnoAANoAMOAN NN

Edwin Wilson Cambridge

CHALK ROCK MOLLUSCA

Hy

irae Candidate for admission as a Fellow must be tesa by three or more Fellows,
Res who must sign a Certificate in his favour. The Proposer whose name stands first upon
a i the Certificate must have a personal knowledge of the Candidate.

va

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Proceedings of the Geological Society ........cssscenccseceeentereccseseerseesecneeerssenee i-ly
PAPERS READ.

1. Dr. J. W. Gregory on the ‘Schistes lustrés’ of Mount Jovet (Savoy) ........++.- if
2. Mr. J. E. Marr on the Tarns of Lakeland..............ccssceccoscscteceeetees Seo 12
3. Prof. T. G. Bonney on the Serpentine, Gneissoid, and Hornblende Rocks of

pitexiuizaed so (PIRLO D>) sac... cccvecs ads vae os dqs she bd tee Sas owes see een ee 17
4, Col. H. W. Feilden on the Geology of Kolguev Island, with an Appendix on

the Erratic Boulders by Prof. T. G. Bonnoey...........-c..scscerscse-taheeeseeeaae 52
5. Mr. Frank Rutley on the Alteration of certain Basic Eruptive Rocks from

brent Tor, Devon. —[Abstract.] <.....cc0.f.ivcce<tasense@ «eptdeeeeeiwen see 66
6. Mr. Henry Woods on the Mollusca of the Chalk Rock. (Plates II.-IV.) ...... 68

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Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 99

7. A Dettmitation of the CenomManian :—being a Comparison of the
Corresponvine Bens in Soura-weEsteRN EneLanp and WustEeRN
France. By A. J. Juxes-Browne, Esq., B.A., F.G.S., and
Wittam Hitt, Esq., F.G.S. (Read January 8th, 1896.)

[Puate V.]
ConTENTS.
Page
Meer anical UEOUNCEIOID \c.-sccsccecens: cueccs fes0ssatsevatssnentenes 99
II. A brief Description of some Sections on the South Coast of
1S 1g) TN SS SS nee eee Seca eee Ree ee Deere pe MEST 103

III. A Study of the. Cliffs between Cape La Héve and Brunval... 115
IV. A Correlation of the Cenomanian Deposits in the Calvados,

UTE RRINVGL TS 2) 1G) | Bee de ee nee Ree ee a 126
VY. The Minute Structure of some of the Beds in England and
LPT ES aD Oe as Roe 2 oR eee ee a pee ee 136
VI. Critical Remarks on some of the Fossils .............eeceeceeees 142
VII. Lists of Cenomanian Fossils found in Devon and. in
ENUM AN Wales et Sasa ened eae cidePincsne daelsicSinuies amopineaee Sces.nckne 158
SeOHe Summary and Conclusions .....;..-000sssasscrssessseasacernveoases 170
eR TACIT «ace cpsiacenscicsinsaeiiorisine de 113, 114, 118, 124, 172

I. HisroricaL INTRODUCTION.

Tux object of this paper is to compare the beds which form the
lower part of the Upper Cretaceous series in those parts of Western
France and Western England which are nearest to one another.
In England these beds are known by the names of Gault, Upper
Greensand, and Lower Chalk; in France they are classed under
d’Orbigny’s ‘ Albien’ and ‘Cénomanien’ stages. It is well known
that in both countries the depcsits referable to these groups change
their lithological character so greatly, in passing towards the west
and south-west, that different observers have formed different
opinions in their attempts to correlate one area with another.
Further, no geologist has yet endeavoured to make a careful com-
parison of the French and English types; but it is only by such a
comparison that the true stratigraphical position of d’Orbigny’s
Cénomanien stage can be determined, and that the limits of this
stage in areas outside the typical Cenomanian district can be fixed.

The name ‘Cénomanien’ was introduced by d’Orbigny in 1847
to designate the lower part of the series which he had previously
called ‘ Turonien,’ when he found that this lower portion contained
a fauna essentially distinct from that of the upper part... He
then proposed to retain the name ‘Turonien’ for the upper part,
and to adopt the name ‘ Cénomanien’ for the lower part, taking the
name from Le Mans, in the Sarthe, the Cenomanum of the Romans,and

1 «Paléont. Frangaise: Terr. Crétacé, vol. iv. p. 270. See also his ‘ Cours
ere de Paléontologie et de Géologie stratigraphiques,’ 1852, vol. ii.
p. 631.

Q.J.G.8. No. 206. I

100 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

regarding that district as the typical area of his new stage, because
the deposits there were of considerable thickness and were rich in.
well-preserved fossils. oh |

Unfortunately d’Orbigny himself fell into error regarding the
deposits which should be included in his Cenomanian stage in the
West of France. In the Sarthe there are no Lower Cretaceous
strata, neither are there any beds containing a typical Albien fauna,
so it is not surprising that d’Orbigny included the basal clays and
greensands in his Cenomanian; but he also believed that his Albien
stage was wanting near Havre, and that everything seen there
above the Kimmeridge Clay was of Cenomanian age.’

This belief of d’Orbigny’s was doubtless one cause which retarded
the progress of opinion respecting the limits and components of the
Cenomanian stage. Another cause is certainly to be found in the
local and exceptional nature of the beds in the district which was
chosen as the type, both as regards their lithological characters and
the assemblage of fossils that they contain.

A study of what has been written by French geologists con-
cerning the Cenomanian shows us that they have constantly found
a difficulty in determining what beds in other parts of the country
Should rightly be regarded as the equivalents of the Cenomanian of
the Sarthe.

In perusing the Vicomte d’Archiac’s ‘Etudes sur la Formation
Crétacée’* we have been struck by the general accuracy of his
correlations. He evidently had a masterly grasp of the subject and
a keen eye for the structure of a country, and for tracing definite
horizons in a changeful group of beds. He anticipates d’Orbigny
in separating the ‘groupe de la craie tufau’ of Touraine and Anjou
from his ‘ groupe du grés vert,’ and he divides each of these groups
into three stages. It is possible that he made some mistakes in the
determination of his fossils, but the grouping of his beds appears
to be more correct, stratigraphically, than the grouping adopted
by @’Orbigny in his ‘Cours élémentaire de Pal. et de Geéol. strati-
graphiques’ of 1852. Certainly the comparisons made in his rapid
traverse of the Sarthe, Orne, and Calvados are very correct, and we
think that he laid a sufficiently accurate basis for a more detailed
correlation of the Cenomanian deposits, if his successors had only
worked along the same lines, and had not depended so entirely on
the minutiz of paleontological evidence.

Unfortunately the late Prof. Hébert, influenced probably by the
statements of d’Orbigny, and struck by the differences between the
Cenomanian faunas of Havre and of Le Mans, propounded the
hypothesis that the greater part of the Cenomanian of the Sarthe,
or Gres du Maine, as he called it, was newer than the ‘ craie
glauconieuse’ of Havre, and that the former was a local deposit
which was not represented by anything on the northern coast.
This was combated and disproved by M. Guillier and M. G. Bizet,
who showed that chalky beds containing Rotomagian fossils occurred

1 ‘Cours élémentaire, etc.’ vol. ii. pp. 619 & 635.
2 Mém. Soc, Géol. France, ser. 2, vol. ii. pp. 1-148 (1846), published 1847.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 101

in the midst of the Gres du Maine, and that the ‘ Rotomagien’ or
Rouen Chalk is merely the chalky facies of the upper part of the
Cenomanian of the Orne and Sarthe. This view has been accepted
by Prof. A. de Lapparent and by the officers of the Service de Ja
Carte géologique de France.

French geologists, however, have not reached the end of the
difficulties and controversies to which the local and isolated facies
of their typical Cenomanian has given rise. They are even now at
variance with regard to the line of separation between the Albien
and Cenomanian stages. The Albien fauna of d’Orbigny was mainly
that of the Lower Gault; the fauna of what we know as the Upper
Gault and Blackdown Beds was by d’Orbigny included partly in
the Albien and partly in the Cenomanian, under the mistaken
impression that our Blackdown Beds represented a part of his
Cenomanian.

Gradually, however, it became known that between the typical
Albien and Cenomanian faunas there was a distinct zonal assemblage
in the Upper Gault of Wissant, in the Gaize of the Ardennes, and in
the Vraconnien of the Jura. The question then arose as to whether
this zone of Ammonites inflatus should be included in the Albien
or in the Cenomanian, and on this question French geologists differ
to the present day, some thinking with Prof. de Lapparent that it
should be classed as part of the Albien, others agreeing with Prof.
Hébert and Dr. Barrois in regarding it as Cenomanian.

Further, Dr. Barrois’s researches in England and in the North-
east of France disclosed the existence of beds containing Pecten
asper between the zone of Ammonites inflatus and the base of the
Chalk in those regions. Now Pecten asper is a common shell in the
Cenomanian of the Sarthe, and consequently French geologists are all
of opinion that the true Cenomanian contains an equivalent of this
zone of Pecten asper.

In England, as Dr. Barrois has shown, the Upper Greensand of
Wiltshire, Hampshire, and Dorset may be divided into two zones,
the lower being his zone of Ammonites inflatus, the upper being his
zone of Pecten asper, which includes the chert-beds and green sands
of Warminster and other places. The result of French investi-
gation, therefore, has been to tell us that our subdivisions into
Gault, Upper Greensand, and Lower Chalk do not tally in any way
with their Albien and Cenomanian stages, and that if we wished
to adopt the French nomenclature we should have to draw a hard-
and-fast line in the middle of our Upper Greensand.

Having thus briefly indicated the history of French opinion, and
mentioned the difficulties which have arisen in comparing the
sections on each side of the Channel with the beds in the area
which was selected as the typical facies of the Cenomanian stage,
let us now as briefly indicate the progress of English studies in the
same field.

It is to William Smith that we owe the nomenciature and
primary classification of the English Cretaceous strata: he found
in Wiltshire and elsewhere a succession of (1) clay, (2) and,

12

102 MESSRS, A.J. JUKES-BROWNE AND W. HILL: [May 1896,

and (3) chalk, to which he gave the simple names of (1) The Gault,
(2) The Greensand, and (3) The Chalk. His Chalk was subsequently
divided first into Lower and Upper, and more recently into Lower,
Middle, and Upper. For a long time the Gault and Upper Green-
sand were regarded as distinct formations or stages, but the
tendency of modern opinion has been to consider them as different
lithological phases of one formation or stage, and we have no doubt.
that a new name will have to be found for this combined Gault-and-
Greensand stage.

The work of English geologists has therefore tended to consolidate
the Gault and Greensand, and to separate them as a whole from the
overlying Lower Chalk, which has generally a bed of glauconitic
marl at its base, and is often marked off from the Upper Greensand
by a very clear plane of division. The fossil assemblages agree
with this method of classification, and no modern English geologist
would imagine that a more natural division could be made by
grouping a part of the Upper Greensand with the Lower Chalk.

This being so, it has for some time seemed odd to us that a
different line of division should be taken by French geologists, and
the question occurred to one of us whether they were fully justified
in correlating the beds which they group as Cenomanian. This idea
was greatly strengthened by a recent examination of the Devon
coast-sections where the Upper Greensand is well developed, but
the Lower Chalk is represented by a peculiar set of arenaceous beds
which differ from anything else in England. The fauna of these
beds is also peculiar. Itincludes Pecten asper, and many species which
in England are only found in the Upper Greensand? others which are
proper to the Lower Chalk, and some which have only hitherto
been found in France. Both of us were struck with the similarity
of this fauna to that of the French Cenomanian.

Having thus obtained what promised to be a key to the difficulty—
for if Paster asper occurred in a representative of the Lower Chalk
in England, it might do so also in France—we proceeded to enquire
how far this occurrence of P. asper might be responsible for the
supposed necessity of grouping the Greensand zone of P. asper in the
Cenomanian stage. We found that the succession of beds in the
department of the Sarthe had been carefully worked out,’ that the
similar series in the Orne had been examined and described by
M. Bizet, of Belléme, and that the Havre and Rouen sections had
been described by Prof. Hébert, M. Lennier, and others, but that
little or nothing was known about the intervening area in the
Calvados. So far as we could learn, no one had published any
detailed comparison of the succession in the Orne and Sarthe with
the sections near Havre, and consequently it was uncertain how far
south the Gault extended, and whether the base of the Cenomanian
in the Orne and Sarthe corresponded with any definite horizon at
Cape La Heve. This want of continuous stratigraphical information
certainly seemed to leave much to be desired in the way of evidence,

1 See Guillier’s ‘ Géologie de la Sarthe.’

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 103

and suggested that more accurate views might be obtained by an
investigation of some of the principal exposures along a traverse
from the coast in the direction of Lisieux, Vimoutiers, and Mortagne.

In planning out the route of this traverse we owe thanks to
M. G. F. Dolltus, of Paris, and M. Bizet, of Belléme, for advice
and information regarding the best localities to visit. The cliffs
between Cape La Heve and Etretat were first studied in detail, and
subsequently two excursions were made to localities in the Calvados
and Orne, between Honfleur and Mortagne.

[Note.—It should be mentioned that the examination of the
French sections was accomplished entirely by Mr. Hill, and that the
exposures in the Calvados had to be discovered without guidance,
exvept so far as the outcrops were shown on the sheets of the Carte
géologique détaillée de la France. The Devon coast-sections were
worked out by myself in 1894 for the Geological Survey, and the
Director-General kindly permits us to publish some of the infor-
mation then obtained.—A. J. J.-B. |

In arranging our descriptive notes for comparison we have thought
it best to place the English sections first, because this part of the
Cretaceous series is much more complete, more frequently exposed
in coast-sections, and more clearly divisible into two distinct portions
or stages than it is in France. Consequently we feel justified in
taking the English succession as a standard, and in endeavouring to
bring the French succession into accord with ours. We believe
that we have succeeded in doing this, and that as a result we shall
have supplied French geologists with a better and more definite base-
line for their Cenomanian stage. We think that the present state
of confusion has arisen from their having adopted an opposite course,
for they have taken a local and incomplete set cf beds as a standard,
and have tried to fit the more normal and complete succession
with this unsuitable type. It is just as if we had taken the Devon
type of these two stages as a standard, and had endeavoured to
correlate the Gault and Lower Chalk of Folkestone with that local
and peculiar type—without studying the intervening exposures,

II. A BRIEF DESCRIPTION OF SOME SECTIONS ON THE SoUTH
Coast oF ENGLAND.

The sections which most clearly exhibit the relationship of the
Gault, Upper Greensand, and Lower Chalk are those on the coasts
of the Isle of Wight, Dorset, and Devon.

1. Isle of Wight.

The stratigraphic succession of these groups in the Isle of Wight
is fairly well known on both sides of the Channel, to the French
from the writings of Dr. Barrois, and to us from those and from
the second edition of the Geological Survey memoir on the island ;
so that we need only call attention to such points as have a
special bearing on our present purpose. |

x

104 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

In the first place, it is worthy of note that all the component
members of the Cretaceous system are thicker here than at any
other place along the south coast. Taking the Gault and Upper
Greensand together, they have a thickness of 270 feet at Gore Cliff
and of about 230 at Compton Bay, while the Lower Chalk is 200
feet thick near Culver Point, and is probably but little less at
Compton Bay.

In the next place, no hard-and-fast line can possibly be drawn
between the Gault and Upper Greensand; there are a set of passage-
beds, sandy micaceous clays, which have been referred to the Gault
by some authors and to the Greensand by others. As Ammonites
rostratus was obtained from these sandy clays by the Survey fossil-
collector, it would appear that they belong to the same zone as the
overlying micaceous sands, and should not be referred to the Lower
Gault.

Whether these passage-beds be included in Gault or in Greensand,
it is equally impossible to take a definite base-line for the zone of
Ammonites rostratus, There is the same'kind of passage in other
parts of England, and so long as the Amm. rostratus-beds are
regarded merely as a zonal subdivision of the Gault-and-Greensand
group there is nothing surprising init. Dr. Barrois has taken the base
of the yellow sands near Ventnor as the base of the Cenomanian stage
in England,’ but the bed of sandstone which there forms a convenient
base-line has not been detected in other parts of the island. His
endeavour to fix the base of the zone of Amm. rostratus and to make
it the base of an English Cenomanian is no doubt a logical application
of the classification which he had adopted for the beds in the East of
France, but we think that arrangement was founded on a mistaken
view of the chronological value of the typical Cenomanian of
Maine and Normandy, a view which may be traced to the erroneous
correlations of Prof. Hébert.

The next point for consideration is the junction of the zone
of Ammonites rostratus with that of Pecten asper. This is of
importance because some French geologists, notably Prof. de Lapparent,
are prepared to throw the former into the Albien and to take the
latter as commencing the Cenomanian. In the Isle of Wight,
however, there is no break or great change of fauna at this horizon:
the chert-beds are mere local deposits of organic silica (sponge-
spicules), and Pecten asper occurs below as well as above them.
No English geologist would think it natural to detach these beds
from the Greensand and to group them with the Lower Chalk.

When we come to the junction of Chalk and Greensand, however,
the case is different. Even here there is a passage and no sharp
line of demarcation, but the passage is very rapid and it coincides
with a great change in the fauna. Above the highest layer of
cherts there are two beds which we should group with the Upper
Greensand, and the uppermost of these passes into what we regard
as the true Chloritic Marl or basement-bed of the Chalk. The

1 © Recherches sur le Terrain Crét. Sup. de l’Angleterre et de l’Irlande,’ Lille,
1876.

Vol. 52.] - A DELIMITATION OF THE CENOMANIAN. ~ ‘105

following section was taken by one of us in 1880 from the slipped
mass at Collins Point, near Ventnor :—
Feet.
6. Chalk Marl with scattered glauconitic grains near the
base, Ammonites varians and Pecten Beavert.. ......++-
5. Greenish-buff glauconitic marl full of fossils and phos-
phatic nodules, Ammonites varians, etc. .......0.seeeee
(4. Compact, dark green, sandy marl, with quartz and
glauconite, but few fossils or phosphatic nodules ..... 23
| 3. A layer enclosing lumps of calcareous sandstone partially
Bi cue phosphatized, irregular pieces of dark phosphate and
DEOKOM EL COLCMAS PCT oe ina paagcasacancebardcce=talsincas about 0%
2. Yellowish-green sand mottled with darker green ; yields
fh Pecten orbicularis, Ostrea vesiculosa, and Pecten asper. 2
1, Continuous layer of dark-grey cherty stone with compact
\ Breen samc below, SCCM LOM vescnccnscncssienseceenancnpenes 4)

The material of 2 passes into that of 4 between the lumps of
phosphatized stone in 3. At Niton 3 and 4 form a kind of boulder-
bed full of such lumps, with phosphatized sponges, Cardiaster fossarius,
Pecten asper, Terebratella pectita, and other fossils, but without any
Ammonites. The Chloritic Marl (5), on the other hand, might be
called a ‘Cephalopoda Bed,’ so abundant are ammonites of the
species varians, Coupet, and Mantel, with Turriltes tuberculatus
and Morristi. It is also characterized by the remarkable siliceous
sponge Stawronema Carteri (Sollas), which has not yet been found
below this horizon, nor far above it.

As one of us spent a week in 1880 for the purpose of examining
these beds at the base of the Chalk, and afterwards engaged the
services of Mr. M. Norman, of Ventnor, in collecting carefully from
them, it seems desirable to give the list of fossils then obtained,
in order to show the difference of the faunas. In this list the
numbers above the columns indicate the beds as numbered in the
section just described :—

CHALK.

GREENSAND.

2 3, 4 5
Porirera (SPONGES).
Halirrhoa agariciformis (phosphatized)......... oka * ree
Plocoscyphia labrosa, Smith (phosphatized) .. a Soe *
BCR ICU SECO ei crtac gD. co tiewise nae sees sainscereaeoverers ci * aes
Siphonia (phosphatized) .........c.cecscsccseeeoare * on
Stauronema Carter, Sollas .......cccccecceeseeeees ot x
ACTINOZOA.
Micrabacia coronula, Goldf, ..........0see00e sons ie *
EcuinoperMata and ANNELIDA.

Cardiaster fossarius, Benett .........seccecseeees x * =a
Discoidea SUG CUA, LESKO .....<csseveeescenensees *
Hemiaster Morristi, Forbes ...........0secceeseeees as oe *
Holaster levis, var. CATINAtUS .....c.cceceeeceeees * x *
ICRP APs TAT ay eet Melange cans Je Sp ial dendni.d a bn wwneinibe *
Vermicularia wmbonata, Sow. sscccerssceceeeees %

106 MESSRS, A.J. JUKES-BROWNE AND W. HILL: [May 1896,

TABLE continued.

2 3, 4. 5
BRACHIOPODA.
Megerlia (Kingena) lima, Defr. ............ Passel (usin eee *
Dercbratell @ Pectala «NOW, 0. -.4.sacsensncearaeacnai: ses * *
Terebratulina striata, Wahl. ............. Beau cee ate *
Terebratula biplicata, SOW. .......csceceessecsoeees Saas alae x
= semiglobosa (?), Sow. ....s.seeceeees oe biel *
Rhynchonella Grasiana, A’ Orb, .........0.00000+ acs ick *
a3 Manitelliana, Sow. ...-..seimers- aa ae *
LAMELLIBRANCHIATA.
PAN OTST: yo acecen ens omepinas ose cele Sx anicien ens ae tV si 590 ae *
Ostrea vesicularis, Lam. ....... Fee ee iret | ee * é *
33) westerlosn, [SOW itis. Sockccon eden pte sae: * * %
» carinata, var. frons, Patk, ...qecs0-00+ .0: ate ane *
Plicatula pectenoides, Sow. ........ Eee oe awed * * *
. DIATE AON oe ena eC o scene Nee: aehiere * *
BR ECUCI ASPET, AGAIN, “haa vaetocenssowsaeeeest ow aven-: * ® ase
» Galliennti, d’Orb.......... SOME te tacitat % Exe
Bb WAORUECILUTIS AO OM... oddiaivendonasagaeacssdraed * * *
| 4, sp. nov. (allied to jissicosta, Eth.) ...... is * Ee
Janira quadricostata, SOW. .........0. . seaseeees x pe ae:
9 —« QUINGUueCOSTATA, SOW. .......0,00--008 Beret. es * *
Tima globosd, SOW. .s..dvce.tebee nave sSogsnoobsuide * *
Cardium hillanwm (?), Sow. ...2..seseecececeeees bat 3s *
Anca Matlleanad, COxD: ..daseusa0isvonmeseverndsad divs be *
Bon 1eUES@ (2), Pick. CC AROUK sa.. caemasteace es ee at *
Crassatella, 8p. (Casts) ..0.....asecscercrsarsecereses Se yes *
Cardita tenwicosta(?), SOW. ........0sscescceesenee: oes ? ca
Cyprina quadrata, dOrb. ...... ah deb ner nas Bee %
GASTEROPODA.
LLANE OTIS ISS a @ Yr: eo So neo * hice
9 sp. slaieie’=iatatalaiolalotuistelelele Oosdoc slolaleleleleveictaleiateleleietets sre *
Pleurotomaria Rhodani, VOrb, .............0000- % *
Solarium ornatum (?), SOW.......ceseecseeees scndao * %
CEPHALOPODA.
Ammonites Mantelli, SOW. ......ceserececsosecsone : *
se navecniaris: Mant. . Ubeasencere ascent. ee = *
a4 VAMGIS, SOW. Ghee onneeepeeeaneeres ace os *
= » | var. Cowper, Brong, .....-... ae *
Turrilites Morrisit, Sharpe ..........c.c0s0+s00 Sa : *
oe tuberculatus, BOSe .......ccsesessesse *
FAQHULES GTINALUS (2), SOW. 2.00. decteecsisvsssoeesa% aoe *
Nautilus subradiatus, VOrbd. ......esecceeveceves: fi *
ots HELP ATISUS. SOW. (an 24/0 aceeeennee es mses ‘ . *

This list appears to show that it is Bed 5 only which contains the
characteristic fossils of the Chloritic Marl, and that in passing from
4 to 5 we cross the plane of division which separates two important
faunas and two primary subdivisions or stages of the Upper Ore-
taceous Series. There are of course some species, particularly of

Vol. '52.] A DELIMITATION OF THE CENOMANIAN. 107

Jamellibranchiata, which pass from one stage to the other, but the
sudden incoming of a new and varied set of cephalopoda is sufficient
to mark off one fauna from the other.

With respect to the Chalk Marl little need be said; it consists of
alternating soft and hard beds, and the most abundant cephalopods
are Ammonites Mantelli, Amm. navicularis, Amm. varians, Turrilites
costatus, I’. Scheuchzerianus, T. tuberculatus, Baculites baculoides,

and Scaphites equalis.

The higher part of the Lower Chalk is massive, white, and

comparatively unfossiliferous, ‘but at the top is a band of grey marl

(zone of Belemnitella plena).

2. Dorset.
In Dorset both the stages above described—1. ¢. (1) the combined

Gault and Greensand, (2) the Lower Chalk—are much thinner than

in the Isle of Wight. The Gault-and-Greensand stage averages
from 140 to 160 feet thick, but, instead of becoming steadily thinner

to the west, the minimum thickness seems to be at Whitenose, near

Weymouth, and in the extreme west of the county it swells out by
the addition of sandy matter to about 200 feet. The Lower Chalk
is about 140 feet thick near Swanage, but thins to less than 40 at
Lulworth and Whitenose ; whether it continues to thin towards the
west is not known, as it is faulted out for a considerable distance
and does not appear in the cliffs of West Dorset.

The most easterly cliff-section is at Ballard Hole or Punfield
Cove near Swanage. This was well described in 1876+ by Mr. H. G.
Fordham, and, checking his account by Mr. Strahan’s more recent
measurements,” we have the following sequence :—

Section at Ballard Hole.

Feet.

Buff-coloured marl (zone of Belemnitella plena) ......0006+ 6

Alternations of hard whitish chalk and layers of grey marl. 84

; Yellowish sandy chalk with phosphate-nodules............ (2?) 6
| Whiter chalk with a hard bed at the base full of Bra-

Lower Cinaux } chiolites (Plocoscyphia) and some phosphates ......... 13
143 feet. { Marly chalk, in alternating white and grey beds passing

down amtodtihe ext .s..tasqaassdictseasdadecasezecennscnaes 30

Glauconitic marl with fossils and phosphate- -nodules,
Ammonites varians, Scaphites equalis, Holaster sub-
Glovosus, eve. (Ciloritic MAN)... ..<-..cecceceseneacsoensces 4

(Nodular sandstone, consisting of irregular lumps of cal-
| careous sandstone embedded in greenish sand, Pecten

asper, P. orbicularis, Ostrea vesiculosd ........s.eseeeees 5
Greenish sand with occasional calcareous concretions ...... 4
‘ Uprrr Green sand without calcareous nodules, but with scattered
GREENSAND,’ ¢ fragments of brown phosphate, Amm. rostratus......... 17
71 feet Two layers of greenish sandstone with dark green sand
Pea EM HORAN 2e garecianas enc deedemamnnneasevieed ccsiiwewehicewat we 5
Bluish sandy clay with three stone-beds, one at the base ;
Ammonites rostratus, Cucullea glabra, Thetis Sowerbyt,
Ly Arca carinata, and Vermicularia concava .........0+004+ 40
Gav.tt.—Blue sandy clay passing down into stiffer clay ............ (?) 84

1 Proc. Geol. Assoc. vol. iv. p. 506.
2 Geol. Surv. Mem. ‘ Geology of the Isle of Wight,’ 2nd ed. 1889, p. 66.

108 MESSRS. A, J. JUKES-BROWNE AND W. HILL: [May 1896,

How much of the Lower Chalk should be regarded as belonging
to the zone of Ammonites varians is doubtful, but it probably
includes the sandy chalk with phosphates, and this would make a
thickness of 53 feet.

It is especially noteworthy that there can be no doubt where the
line between Chalk and Greensand should be drawn in this section.
Here everyone has taken the same horizon, for there is no passage
as in the Isle of Wight, but an abrupt change or break at the base
of the Chloritic Marl, which rests on an irregular surface of the
underlying sandstone as if a certain amount of current-erosion had
taken place before its deposition.

The nodular sandstone is clearly the equivalent of the beds which
contain similar concretions and the same fossils in the Isle of Wight,
but the chert-beds are absent; as, however, they are only 13 feet
thick at Compton Bay according to Mr. Strahan, it is not surprising
to find them absent here. ‘They are in fact a local and ‘variable set
of beds, and are absent over a large part of Dorset, though where
present they always come in at the same horizon, and, as we shall
presently see, they set in again a little farther west.

At Ballard Hole Pecten asper has only been found in the nodular
sandstone, but as the sandy material of this bed passes down into
the greensand below it is impossible to say how much should be
included in this zone. There is in fact a complete passage down
into sand that contains Ammonites rostratus. .

As in the Isle of Wight, different observers have drawn the line
between Greensand and Gault at different horizons. Mr. Fordham
takes the Upper Greensand down to the lowest stone-bed and thus
gives a thickness of 71 feet to this division. Mr. Strahan draws
the line higher up, assigning only 45 feet to the Greensand and

110 to the Gault: Neither have attempted a division into zones, and
we do not yet know how much of this thickness should be assigned
to the zone of Ammonites rostratus, and how much to those of
A. lautus and A. interruptus; it is not probable, however, that
the division into zones would coincide with either of the lines taken
to separate Gault from Greensand.

The next fairly complete and accessible section is at Lulworth.
The Lower Chalk was measured here by one of us in 1892, and
found to be only 38 feet thick, a remarkable diminution of thickness.
Dr. Barrois gave a detailed account of the Greensand portion in
1876,’ and Mr. Meyer has kindly supplied us with a note on the
beds at the junction of the Chalk and Greensand. Combining these
sources of information, we have the following sequence :—

1 «Recherches sur le Terr. Crit. Supérieur, etc.,’ p. 89.

Vol. 52.] _ A DELIMITATION OF THE CENOMANIAN, 109

Section at Lulworth Cove.

(Soft, greenish, buff-coloured marl (zone of Bel. plena)...... 6
| White chalk in regular beds, divided by thin seams of marl 16
Lower CuA.k. { Soft, whitish chalk, blocky and not bedded, enclosing
siliceous nodules or flints..........scs.sscccssceceeeseeseeees 12
| Glauconitic chalk with phosphatic nodules .................. 4
(Hard, nodular, calcareous sandstone (1 foot), passing
down into similar but more sandy and evenly-bedded
ZONE OF FUNG AMAEEEN, HOSSEER eng nS cseScdac onen hs snvansnsaeneess tn

PECTEN ASPER. Sand with two or more RAEN ON CMEUU Sosccansecse bee dea s6eel D
| Marly greensand with small phosphatic nodules, Pecten
y) asper andy miamy, other fossils .45523.<s2sheetisndennsdescs ven
( Greensand with beds of calcareous sandstone ............... 14
z, A Greenish sand with an oyster-bed 10 feet down anda layer
: Seleliaaa j of fossiliferous concretions at the base .................. 16
ROSTRATUS. | Grey micaceous sands with two layers of grey sandstone :
L PCRIICMAPIE CONCHIIE aasciiswinanapacsesddistwanissedas ck’ 44
Black dandy Clay SGOR HOT 211i js aona ne cnistcarsesasucemeadeoccnes 1d
GAULT
i Backes LCN CLAS sede, cass denbansediwincadacessnaaVedcuosea: ads (?) 45

In this section a noteworthy point is the occurrence of flints in
the Lower Chalk. These flints do not disengage themselves like
ordinary chalk-flints, but have more resemblance to the siliceous
concretions which occur in the Lower Chalk of Wiltshire! They
are enveloped in a thick coat of white siliceous chalk, which often
seems to pass inward into grey or black flint and outward into the
pure chalk. The amount of completely silicified matter or flint
varies greatly, being sometimes a fairly large mass and sometimes
a mere nucleus, and some concretions have none at all.

These flints also occur at Whitenose and in many other parts of
West Dorset, and we call especial attention to them, both because
the idea that real flints do not occur in Lower Chalk is still current
in some quarters, and because siliceous concretions of the nature of
cherts occur in the Cenomanian of Normandy.

Lithologically there is nothing at Lulworth which can be called
Chalk Marl, but, as Dr. Barrois records Ammonites varians and
Eth ynchonella Mantelliana from these beds at Ringstead Bay, they
may represent part of the Chalk Marl. Whether the basement-bed
with its phosphate-nodules represents the true Chloritic Marl or
Stauronema-bed we think very doubttul; more probably it should
be regarded as a condensed equivalent of the lower part of the
Chalk Marl.

The junction of Chalk and Greensand is even more abrupt and
well marked than at Punfield, the base of the glauconitic chalk
resting on an uneven and current-washed surface of the underlying
sandstone. ‘The uppermost foot of this sandstone, moreover, is
rough, nodular, and more calcified than the part below, as if it had
been exposed to some alterative influences before the deposition
of the overlying chalk.

The zone of Pecten asper is well marked; the chert-beds are
coming in again, and, with a marly greensand below, in which
Dr. Barrois also found P. asper, give the zone a thickness of 20 feet.

1 See Quart. Journ. Geol. Soc, vol. xlv. (1889) p. 403.

110 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

But, with the exception of a rare specimen of Ammonites Mantelli,
the Chalk Marl cephalopoda do not descend below the base of the
Chalk.

The section at Whitenose appears to be similar to that at Lul-
worth, but thence westward there is no cliff-section of Cretaceous
rocks for a long distance. Inland exposures as far west as Brid-
port show a sequence like that of Lulworth; the Lower Chalk is as
thick or thicker, and has the same fossiliferous nodule-bed at the
base.

Between this district and Pinhay, near Lyme Regis, a distance
of about 14 miles, the whole of the Chalk has been removed by
Tertiary erosion, but sections of the Gault and Greensand show
that this lower stage attained a thickness of nearly 200 feet in the
extreme east of Dorset.

3. Devon.

We now come to Devon, where the Greensand attains a great
thickness, and the representative of the Lower Chalk differs as
much from the ordinary English type as that does from the French
Cenomanian. We have seen that in West Dorset the Lower Chalk
is still chalk with a definite basal nodule-bed. Where the Chalk
comes in again below Pinhay, west of Lyme, the succession at the
junction of Chalk and Upper Greensand is as follows :—

Section below Pinhay.

Feet. In.
(7. Hard, rough, nodular chalk, with Jnoceramus mytiloides,
| Cardiaster pygmeus, and Cidaris hirudo ....6.cccscceeesevens di. A9
TT { 6. Hard glauconitic chalk, with Juoceramus mytiloides and
; OUI ATIS HUM O Nias vin soos pea amer ada haaa cana apie otc eee eee 19
5. Softer chalk, full of quartz and glauconite, with many
L phosphate-nodules and derived fossils at the base............ 0 9
4, Hard, rough, quartziferous limestone with large green-coated
( lumps, fossils not abundant. About..............:eeseeeeeeees 1 0

M.4 3. Hard, compact, shelly limestone, fine-grained above, but
| coarse and quartzose at the base, which rests on an eroded
a surfate Of-the bed below fo. sceds.vosesscesecaste Sc oddae od aveatene 1 6
2. Calcareous sandstone with few fossils, indurated and calcified
G in the upper part, softer below ..... jana hs wdpaius + tenoPacenociaae 8 0
*) 1. Chert-beds, fine sandstone with irregular Poneretione of
EHELE PSCC LOM ccs sans sas meme eee emer saaeatscwacsstelet cacscnmeceeaeee 22 0

These beds fall into three natural groups as bracketed, which we
may tor the present call G, M, T.

Group G is clearly the higher part of the Upper Greensand, and
the calcareous sandstone occupies the place of the similar bed in
Dorset. Pecten asper has not been found in it, but the fossils which
do occur are those of its Dorset equivalent.

Group M.—All the beds above the calcareous sandstone are very
variable in thickness. Nos. 3 and 4 are in one place less than a
foot thick, but expand in a shurt distance to more than 3 feet.
The lower bed contains a mixture of fossils which are elsewhere
characteristic of separate zones; some of the so-called ‘zone of

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 1fl

Pecten asper, such as P. asper itself, P. Galliennei, and Catopygus
carinatus; some of the Lower Chalk, such as Ammonites varians,
A, Mantelli, and Scaphites equals; near the base, too, a peculiar
large coralloid polyzoan (Ceriopora ramulosa) is not uncommon,
The upper bed has fewer fossils, but the same ammonites occur
with, occasionally, Scaphites wqualis. These two beds are well
marked off from those above and below, and may be called the zone
of Ammonites Mantelli.

The upper surface of No. 4 is always a layer of brown phosphatic
nodules; these are now ‘ welded’ on to this bed, but the interstices
between them are filled with the material of the overlying bed.
This bed, No. 5, is full of large grains of quartz and glauconite, but
has a chalky matrix, and is much more friable than the bed below.
Setting aside the derived phosphatic fossils, of which there are
many, the commonest fossil in bed 5 is Rhynchonella Wiestit, a
species which is closely allied to RA. Cuvieri. With it are
found Belemnitella plena and Discoidea cylindrica, so that, looking
to the fossils, the bed would seem to be the equivalent of the
Belemmitella-marls of Dorset and other counties. Physically, how-
ever, it is the base of the Middle Chalk or Turonian, for it passes
up into the hard glauconitic chalk which contains only Turonian
species.

Phe to the succeeding yellowish nodular chalk, there can be no
doubt regarding its age; it has some resemblance to the Melbourn
Rock, and may be regarded as its equivalent. We think, therefore,
that the Middle Chalk has here a basement-bed of gritty glauconitic
chalk, containing derived fossils, which bears the same relation to
the Melbourn Rock as the basement-bed in Dorset does to the
Chalk Marl.

If the above inferences are correct, the only beds which can be
regarded as the equivalents of the Lower Chalk in this section are
Nos.3 and 4. Mr. C.J. A. Meyer saw these beds in 1895, and at
once recognized No. 3 as a union of the 10 and 11 of his Beer
Head section,’ No. 4 as his bed 12, and the overlying beds as his
13 and 14. He is now, however, prepared to agree with our cor-
relation of these beds.

Group M, the zone of Ammonites Mantelli, can be followed above
the landslips of the coast-line between Lyme Regis and Axmouth
running out near the top of Haven Hill, above the mouth of the Axe.

West of Seaton the Greensand and Chalk are brought in again
by a fault and a syncline, an excellent section being exposed along
the face of Whitecliff. The details of this will be given in the
Survey Memoir, and it is only necessary to notice here that the
glauconitic chalk (No. 5) is absent, the hard nodular yellowish
chalk (No. 6) resting directly on the zone of A. Mantelli. The
latter, moreover, forms one massive bed from 2 to 3 fect thick,
though careful examination shows that beds 2 and 4 enter into its
composition,

The Upper Greensand is about 160 feet thick, including a sandy

* Quart. Journ, Geol. Soc. vol. xxx. (1874) p. 369.

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Vol. 52. | A DELIMITATION OF THE CENOMANIAN, 113.

representative of the Gault. The following is a condensed view of
the beds which compose this stage in Whitecliff:—

Feet.
Hard calcareous sandstone, few fossils ..........c.cssceccescescecceeees 8
Yellowish sand and sandstone, with numerous layers of chert ... 56
Dark green sand and hard glauconitic stone...............ceccecseeeee 4
Green, grey, and purple sand, with layers and concretions of hard
PpERECOIS SHURSUONO a oecahee ts een tcjen stood ones cue-nseossesaes cocne 70
Dark green argillaceous sand seen for .........scceeeecseceecseseceees 15
153

The beds at the junction of the Chalk and Greensand may be fol-
lowed along the foot of the magnificent range of cliffs which extends
from Beer Harbour to Beer Head, and near that headland the zone of
Ammonites Mantelli can be seen to thicken out rapidly, the thicken-
ing being chiefly produced by the addition of material to its lower
bed, till at Beer Head the whole is about 14 feet thick, and is very
clearly divisible into two parts or beds. The upper bed, 23 feet
thick, is a rough quartziferous limestone with layers of green-coated
nodules, and in it Holaster subglobosus is common ; the lower bed is
in its higher part a hard shelly and gritty limestone, with Pecten
subinterstriatus, P. asper, Ammonites Mantelli, Rhynchonella
dimidiata, Pseudodiadema variolare, and many other fossils; in
this higher part the grains of quartz and glauconite are small, but
in the lower 5 feet the former are large and the rock becomes a
rough and coarse calcareous grit, in which the most abundant fossil
is the large, branching, coral-like Ceriopora ramulosa. The plane of
division between its base and the Upper Greensand below is well
marked.

These two beds include Mr. Meyer’s beds 10, 11, 12, but there is
no clear representative of his 13, the glauconitic chalk or marly
greensand, though there are patches and nests of such sand at the
base of the overlying chalky limestone (Turonian).

We now come to the place where these beds attain their greatest
development ; this is in the great Southern-down landslip, and in
the cliff from which it was detached, known as Hooken Cliff. Here
the zone of Ammonites Mantelli is 24 feet thick, and the succession
is as follows :—

Feet.
6. Hard, rough, nodular chalk, glauconitic at base... 7
5. Greenish, sandy, glauconitic marl, with a few brown
phosphate-nodules in the lower part ; Rhyncho-
nella Wiestii, Belemnitella plena, etc..........06.00- 6
(4. Layer of brownish green-coated nodules at top of
hard, rough, nodular limestone, passing down into
| white gritty limestone with Holaster subglobosus. 6
| 3. Hard, rough, nodular layer with phosphatic matter,
4 passing down into hard shelly and sandy lime-
stone with Pecten asper and many other fossils;
| the quartz-grains getting larger in the lower part,
| and the rock passing into a coarse calcareous
be BAM shoMes With) COFAIS | Wy heen ddexdcencsicnaneasee setae LS

TURONIAN.

ZONE OF
Ammo. ManrTe..i.

Uprrr GRrEEN-
SAND,

2, Even-grained calcareous sandstone with few or no

REBUN Se eet tn y. caseih SecaRNMMe Es eas od ce anvovecocecsocces ?

114 MESSRS, A. J, JUKES-BROWNE AND W. HILL: [May 1896,

The numbers above given correspond with those of the Pinhay
section, and the whole is, in fact, an expanded counterpart of that
section (see p. 112). The upper surfaces both of 3 and 4 are more
clearly marked, while the glauconitic chalk (No. 5), as near Lyme
Regis, passes up into the hard rough nodular chalk above, which
contains Echinoconus subrotundus. It is a remarkable instance of
the rapid changes which take place in these beds that this No. 5
should be here 6 feet thick, though at Beer Head, only 400 yards
away, it is represented merely by small nests of sand.

We are able to state that, as a result of revisiting this section in
company with one of us, Mr. Meyer no longer maintains his corre-
lation of his beds 10, 11, 12 (our zone of Amm. Mantelli) with the.
Warminster Greensand or with the Chloritic Marl, nor of his 13
and 14 with the Chalk Marl. He had in 1874 perceived the clear
lines of demarcation which exist at the top of his No. 9 and at the
top of No. 12, and he now agrees with us that the beds so limited
must represent either the whole or a part of the Lower Chalk.

It is quite possible that only a part of the Lower Chalk is here repre-
sented ; for, whether we take bed 5 of our section to be the zone of
Belemmitella plena or the base of the Middle Chalk. there is clearly
a break between it and the bed below, so that we may assume that
there is nothing to represent that part of the Lower Chalk which
lies between the zone of Ammonites varians and that of Belemni-
tella plena.

Whether material was deposited here and afterwards washed
away by current-erosion, or whether no deposition took place in the
interval, it is at present impossible to say, but for our present
purpose it is sufficient that there is here an arenaceous representa-
tive of the Chalk Marl containing most of the characteristic fossils
of that marl mixed with a number of other species which are
evidently shallow-water forms, and these species are, as we shall
see, almost all found in the Cenomanian of the Sarthe.

Confirmation of our reference of these beds to the lower part of
the Lower Chalk is found in the neighbourhood of Chard and Chard-
stock, the latter place being only 9 miles north of Lyme Regis.
The succession here has been accurately given by Mr. H. B. Wood-
ward, and so far as the Upper Greensand is concerned it resembles.
that of the coast-section. The upper surface of the Greensand is a
well-marked plane, and upon it rests a hard quartziferous and glau-
conitic chalk crowded with fossils; this passes up into softer
glauconitic chalk, which rapidly graduates into chalk with few
fossils. Of this white chalk there is probably 30 or 40 feet, and
there is some thickness of yellowish marl above it, all belonging to
the Lower Chalk.

The basement of this Lower Chalk has been called Chloritic
Marl, and it has long been celebrated for the abundance and good
preservation of its fossils. The assemblage, however, is rather that
of the whole Chalk Marl than that of the Chloritic Marl of the Isle
of Wight, and it also includes some of the rare and peculiar species

1 «Geology of England and Wales, 2nd ed. 1887, p. 392.

|
|

Quart. Journ [To face p. 114.

/
Ise or W}. Feet. Beer Haan.

Limestones. an

NX
|
ww
(=)
ie)

o

Re
= OMe i ee
=
e

64| Chert Beds. |
Tied tear. |g
Sa Oe SNe ces ered =
S | +
= PC renaare «| 5g, _ Grey and ~
Se | Buff Sands, | 3
ica) |
S| ot ll ee ees eA rea Oe
= | Argillaceous |
Chalk y 35 Sands.
\ —
Chert H
Grey :
g || Yellow
Zz |
Zz |
nm
A |
: | |
2 = |
wb |
a 4
Z,
< |
: |
= /
q |
oo) Sandy (

and Gé

Quart. Journ. Geol. Soc. Vol. LIT.

Lower CHuaAuk.

GAULT AND GREENSAND.

(

Istz or Wriaut.

Blocky Chalk.

Chalk Marl.

Chert Beds.

Grey and
Yellow Sands.

Sandy Clays
and Gault.

2

Feet.

120

TABULAR VIEW OF SOUTH-COAST SECTIONS,
(Scale: 1 inch = 100 feet.)

SWANAGE.

Feet.
Blocky Chalk. |84
Chalk Marl. |48
, 40
7
Green and |...
Grey Sands. ee
Sandy Clays |g4

and Gault.

ge

--\Chalk with flints.

Luiworrtn.

Blocky Chalk.

Chert Beds.

Grey Sands
and Sandstones.

and Gault.

Sandy Clay ley

Feet,
Cae CEE (,

[To face p. 114.

_ Beer Heap.

Limestones.

Chert Beds.

Grey and
Butf Sands.

Argillaceous
Sands.

|
|
|
|

{Cenomanian,

GNYSNAAUH ,

Vol. 52.] ‘A DELIMITATION OF THE CENOMANIAN. 115

which occur in the quartziferous limestones of the coast. It is
especially rich in ammonites, and nearly all the species occurring
at Chard are found also in our coast-zone of Ammonites Mantelli, as
will be seen from the list given on p. 159.

The relative thickness of the beds in the principal sections above
described is shown in the accompanying ‘ Tabular View.’

Ill. A Srupy or THE CLIFFS BETWEEN Care La HEvVE anp BRUNVAL.

The bold and almost unbroken line of cliffs which form the
French coast from Cape d’ Antifer to Cape La Héve present a section
of the Cretaceous series from the higher zones of the Upper Chalk
seen at the first-named promontory to the yellow sands which
form the basement-bed, and which can be seen overlying the
Jurassic rocks at Cape La Heéve.

The general trend of these cliffs is about N.N.E. and 8.8.W.,
but at the mouth of the Seine, after passing the lighthouses at
Cape La Heve, the cliff turns to the south, making an obtuse angle
to the general coast-line.

Between Cape La Héve and St. Jouin, a distance of some 11
miles, the strata are nearly horizontal, and the series seen are the
beds from the base of the Cretaceous series to an horizon equivalent
to our Grey Chalk; but at St. Jouin the beds dip gradually to the
eastward, and the whole series is brought down to sea-level.

The section has been well studied by many French geologists,
notably by MM. Lesueur,* le Vicomte d’Archiac,” Hébert,’ de
Lapparent,* and Lennier,’ but even their descriptions do not
furnish a complete account of the whole section, nor do they give
full lists of the fossils found in the various beds.

Moreover, since De la Beche’s visit in 1821,° and Mr. Pratt’s’
notice in 1837, no English geologist seems to have studied this fine
section. Those who have described English Cretaceous fossils seem
to have taken it for granted that the Cenomanian of Normandy
included representatives of both our Upper Greensand and Lower
Chalk ; but, so far as we can ascertain, no one has hitherto attempted
to ascertain how much of this Cenomanian would be regarded as
the equivalent of the Lower Chalk. This has been our endeavour,
but before entering into details we give the general succession of
the series below the Turonian, as seen in the cliffs. This is as
follows in descending order, the grouping being that of M. Lennier
and Prof. de Lapparent :—

1 «Vues et Coupes des Environs du Havre,’ Paris, 1843.

We Etudes sur la Formation Crétacée,’ Mém. Soe. Géol. France, ser. 2, vol. ii.
p- 95.

* Bull. Soe. Géol. France, ser. 2, vol. xxix. (1872), p. 446; «bid. ser. 3,
vol. iii. (1875) p. 512.

+ «Traité de Géologie,’ 2nd ed. 1885, p. 1074.

° Bull. Soc. Géol. Normandie, vol. vi. p. 380, and vol. ix. p. 56 (1880 & 1884).

® Trans. Geol. Soc. ser. 2, vol. i. pt. i. (1822) p. 73.

7 Proc. Geol. Soc. vol. ii. p. 546.

Q. J. G. 8. No. 206. K

116 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

Feet.

(8. Firm greyish-white chalk, with layers of chert-

HOGUIEBN...hacsees cachet eset eee tee enlace nen ete oe 30 to 40
7. Greyish glauconitic chalk, with cherts and hard
caleareous concretions and many brown

phosphatic nodules in the lower part ......... 10 to 11
CrnoMANIAN. 4 6. Greyish-white or yellowish chalk, with many
layers of greyish-black chert. A bed of hard,
grey, shelly, glauconitic chalk occurs in the

middle at St. Jouin, but dies out westward... 70 to 80

| 5. Bluish-grey, sandy. and very glauconitic marl
\ with many black phosphatic nodules ......... 34 to 6
4, Bluish-grey, sandy, glauconitic marl with layers
GAIzE AND of hard siliceous concretions .................++68 23 to 26
Gaunt. }|3. Dark grey, nearly black, sandy, glauconitic
clay with phosphatic nodules at the base...... 10 to 11
p. Aarne 17 Coarse, brown, pebbly sandstone .................. 15 to 16
. 1, Fine, yellow, micaceous sand...........-.sceeeeceeee 70

Upper Neocomian Sands—Aptien.

The sands which form the base of the Cretaceous series at La
Heéve are yellowish, fine, and micaceous, easily dug with the fingers,
and veined or streaked with red-brown iron oxide, which frequently
cements the grains together in thin platy pieces. Near the top are
some concretionary masses of ironstone.

Immediately overlying these sands, and sharply divided from them,
is a bed of brown, pebbly, sandy grit, closely resembling uncon-
solidated Carstone. Many fragments of fossil wood occur in it ; other
fossil remains are rare, but M. Lennier has obtained Ostrea aquila
and Ammonites Milletianus.’ Like all the beds of the lower part of
the Cretaceous series, 1t thins to the southward ; its thickness nearly
a mile east of Cape La Héve is 16 feet, while at Ste. Adresse, south-
west of the headland, its thickness has diminished to 11 feet.

The sequence of these beds has been differently classified by
French geologists at different times.

The yellow micaceous sands and the brown pebble-bed above
them, Nos. 1 and 2 in our section, were first regarded by Prof.
Hébert in 1872° as ‘ Néocomien supérieur,’ which was his name for
the Aptien of d’Orbigny. In 1875, however, he was inclined to
range these sands with the Gault, because he had found fragments
of Ammonites Milletianus in the sands near Octeville, and because
M. Lennier had obtained fossils identified as Ammonites Deluci,
Trigoma Fitton, and Nautilus Bouchardianus from these sands at
Havre. The two beds are so exactly the counterpart of those at the
summit of the Lower Greensand in the Isle of Wight, and described
in the Survey Memoir under the name of ‘Sand Rock Series’ and
‘Carstone, that we cannot help thinking that Prof. Hébert’s first
opinion was the correct one. Certainly it would be strange for
the species above mentioned to occur in an Aptien sand, but
M. Lennier informs us that he is by no means certain of the
identification of these fossils.

* Recorded by Prof. Hébert, Bull. Soc. Géol. France, ser. 3, vol. iii. (1875)
p. 516. ? Op. cit. ser. 2, vol. xxix. p. 449,

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 117

The Gault and Upper Greensand—The Albien of
M. de Lapparent.

Above the coarse pebbly grit comes a dark, sandy, glauconitic
clay, almost black when wet, which passes up into a sandy
and glauconitic marl. This is the equivalent of our Gault and
Greensand, the Gault and Gaize of French geologists ; there is no
plane of division between them, the one gradually passing up into the
other.

The lower part of this division can be conveniently seen near
Ste. Adresse, 3 mile south-west of the lighthouses, where the fol-
lowing section was taken, in descending order :—

( Dark bluish-grey, sandy, micaceous, and glauconitic

Clay Aten fOr heeded, oe aes Sofi Ee own dlad ci «nclunigwiei 7 feet.
Dark bluish-grey (almost black), sandy, and very glau-

conitic clay, containing a few light-coloured phos-

a. phates (dark internally) 20.6 ces dostticaoblddnes delacdes 4 feet.
Bed of phosphatic nodules, contained in a mixture of
the underlying coarse sand and the glauconitic
BANA VAC ey) AISOMG Meteo ias cacloeaile av coi sein pw nena a's op'eien 6 inches,
Coarse, brown, sandy grit, containing pebbles as large
MS HE DEAL ater tces cease dosed convo det aeecuscitesVadadecsvien 3 feet.
risen. « Coarse, brown; sandy grit: 2.2. .c0.is.ics ead enteessavedsse 8 feet.
Soft greyish-yellow sand was seen below this; the
junction-bed, however, was not attainable ......... 15-18 feet.

The bed of light-coloured phosphate-nodules intermingled with
the bed below, the nodules often including small quartz and lydian-
stone pebbles.

The micaceous clay of the Gault passes up into a sandy, glauconitic,
micaceous, and slightly calcareous marl containing small dogger-like
concretions, and as one follows it upward these concretions increase
in importance and number, and finally divide the deposit into courses.
At the top of the division the doggers give place to definite beds in
which silica seems to saturate the deposit, forming hard courses,
which alternate with courses of softer marl.

The following is a detailed section through the Gaize and Gault
at a point nearly 1 mile east of the lighthouses on Cape La Héve :—

Feet. Inches,
Chioritic Marl (see IVS) 212 ae Gn *G
- { Alternating beds of blue-grey mar! and beds of hard
BIICOO MASE CIG ei! ou «mega des vewaupieees Dhavclt oIaceddews 3 6

Dark blue-grey, sandy, glauconitic marl, containing
doggers of hard siliceous stone, arranged more or

GaIzE | HES aN El, EAVOCS MMe Cnate eM rands. tor seemien cat wasaaace ce ot i 0
or A double line of doggers, separated by blue-grey,
UppPER BOM TIVAEL ). .Abirct ssatiadan-o es Solsder tangs es cdendenehaies 1 9
GREENSAND. | Blue-grey, softish, sandy marl ...................0.008 1 3
Dark blue-grey marl, with a line of large and well-
| BUPA AUAUMOOMBOTS es. cecccnche sa saticcessecseatpoenss 1 9
Dark blue-grey marl, with small scattered doggers,
{arranged more or less in lines ...........05...00005 11 0
Guns { Very dark, almost black, marly, glauconitie clay ; a
ee { layer of phosphatic nodules at the base ......... 10 0
Rent § { Coarse pebbly brown sand —.........cecceecveseseceees 16 0
; Mellowitiicgceous sad) /5.....0-.ceserdecveonsresecsveas 10h 20

“118 A DELIMITATION OF THE CENOMANIAN, [May 1896.

Like the pebbly sand, these beds diminish westward; for
just south of the lighthouses the thickness of Gault and Gaize is
28 feet. M. Lennier gives the thickness of the Gault at Canville,
some 6 or 7 miles north-east of Cape La Héve, as 22-23 feet, and he
divides it into three beds." Here therefore the combined thickness
of Gault and Gaize is probably about 50 feet.

Prof. Hébert’ was of opinion that no actual representative of the
Gault occurs at La Héve. He refers to its existence at Cauville,
and states that common Gault fossils were there abundant and well-
-preserved. He also admits its occurrence near Octeville, where
‘the bed of conglomerate is covered by a blue clay without glau-
conite, but containing many small pebbles of quartz and septaria,
with Gault fossils.’

‘At Cape La Heéve,’ he says, ‘this bed is only represented by a
layer of septaria, of pebbles, of vegetable fragments, or of fossils
of the Gault, washed by the waters which brought the glauconite,
and remaniés in the midst, and especially at the bottom of this
deposit, in contact with the conglomerate.’ This appears to be a
description of the basal nodule-bed; these ‘septaria’ are doubt-
less what we have called phosphate-nodules.

He continues as follows :—‘ Je range dans cette derniére assise
(Craie glauconieuse) les argiles noiratres, trés glauconieuses, avec lits
siliceux intercalés, qui, au Cap La Heéve, reposent immédiatement sur
le poudingue a Ostrea aquila ;’ and he gives the thickness of these
beds as from 16 to 20 metres (7.¢., 52 to 66 feet). This great
thickness suggests to us that Prof. Hébert may have included in
this division of the Craie glauconieuse all the beds which have a
blue-grey colour, for our measurements make them 52 to 55 feet.
This view receives some confirmation from his further remarks,
which are:—‘It is true that there occur in this series a certain
number of Gault species, whose existence 1 do not deny, but these
beds also yield a good number of the more characteristic species of
the Craie glauconieuse: among Echinoderms, Epiaster crassissimus,
Epiaster distinctus, Holaster suborbicularis, Cardiaster bicarinatus,
which abound, the last especially, in one of the siliceous beds ;
among the Acephala, Panopea mandibula, Ostrea conica, ete. It is
this lower series that I have designated by the names of the zone
of Holaster suborbicularis and Ammonites inflatus.’

Of the echinodermata mentioned above we found only Epzaster
crassissimus, and that is common above bed 5. We did not find
any below, and even if they did occur we cannot regard that fact as
very significant. There is no doubt that our bed 4 belongs to the
zone of Ammonites inflatus, but both M. Lennier and Prof. de
Lapparent exclude that zone from the Cenomanian; and we are
entirely of their opinion on this point.

Being familiar with the lithological change which our Gault
exhibits as it is traced westward, we see no reason for consider-
ing the Gault to be absent because the clay which occupies its

1 Bull. Soe. Géol. Norm. vol. vi. (1880) p. 358,
* Bull. Soc, Géol. France, ser. 3, vol, iii. (1875) p. 516, —

Section oF THE Cuirrs AT La Hives, BELow tHE CENoMANIAN.
(Taken nearly a mile east of the Lighthouses.—Scale: 1 inch = 10 feet.)

ft. in,

7, “yy

CENOMANIAN 4.6 Cys
oes LEG LE Sy
eb Liga

A ay hy
LOGI, ges ‘a4

CHLORITIC MARL.

UPPER
GREENSAND 1.
1,
w=) 38
fo" 5
GAIZE. Y)
11.0
YY
yy,
vf/ Li
Gavi YW) fs
Yi
| 10-0 Ly
or Yi
Ups
Ys
ALBIEN. “yyy
16.0
APTIAN.

SE ————

about
70.0

A Ge

Glauconitic, sandy, bluish-grey marl, full
of siliceous concretionary masses; afew
black phosphates.

Bluish-grey, very glauconitic, sandy marl,
full of hard siliceous concretions; many
black phosphates.

Softish, blue-grey, glauconitic marl.

Blue-grey marl, with a marked line of
doggers at the base.

Darker blue-grey, sandy, glauconitic marl,
es doggers arranged more or less in
nes. ;

Dark blue-grey sandy marl, with two
marked lines of doggers.

Dark blue-grey, softish, sandy marl.

Line of large doggers in blue-grey marl.

Blue-grey, sandy, and rather glauconitic
marl, with small dogger-like concre-
tions.

Very dark, blue-grey, sandy marl; ex-
tremely glauconitic and almost black
at the base. a

Layer of light-grey phosphates.

Coarse, pebbly, sandy grit, similar to un-
consolidated Carstone.

Soft, yellow, micaceous sand.

120 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

place is full of glauconite. The lower 10 feet of this series is a
material which resembles the Gault at Black Ven, near Lyme Regis ;
it is doubtless from this 10 feet and from the overlying 23 feet of
less dark and slightly micaceous marl that the Gault species have
been obtained. We have, indeed, obtained Ammonites rostratus (var.)
and Ammonites auritus from the upper beds in a large fallen mass
at Cape La Héve. These higher beds we regard as the Gaize or
zone of Ammonites inflatus, the representative ot the Cowstone beds
at Black Ven, of the Malmstone, and of the grey micaceous sands
~ which form the lower part of the Upper Greensand in Wiltshire and
North Dorset.

The Gault is poor in fossils, but we have found Pecten orbicularis
and Hwogyra conica just above the phosphates near Cape La Heve.
The following is a list of the fossils which we found in the upper
beds (Gaize) at Cape La Heéve and St. Jouin :—AHolaster levis, Ostrea
lateralis, O. vesicularis, Avicula (near to Rauliniana, d'Orb.),
Lucina Dupinana, Thetis Sowerby, Avellana incrassata(?), Grbbula
levistriata (?), Ammonites auritus (typical form), A. Raulinianus (?)
small, and A. rostratus (a form resembling one common in the Gaize
of Devizes). In the very highest layer, just below the Chloritic
Marl, Rhynchonella convexa and Rh. Schloenbachi occur.

The section on the preceding page shows the succession of the
beds below the Cenomanian which form the headland of Cape
La Heve.

The Cenomanian (Bed 5).

We dissent entirely from Prof. Hébert’s classification of beds 4
and 5, and agree with that of M. Lennier and Prof. de Lapparent,
for there can be no question as to the exact horizon where the dis-
tinctive Cenomanian fauna sets in. |

M. Lennier gives the total thickness of this division at Cape La
Heve as 32°75 metres (108 feet). Our measurements give only
about 90 feet from the base upwards, and although more chalk is
to be seen above this, it is not well shown or easily examined.
With regard to detailed measurements, our own do not quite tally
with those of M. Lennier, but we differ-only in such manner as may
occur between persons who measure a somewhat variable set of beds
at different times and at different points in a long cliff-section.

M. Tennier* has given a complete section of the Cenomanian of
Cape La Heéve; he divides it into 11 beds, 10 of which are seen
at La Heéve, the uppermost only coming in between Brunval and
St. Jouin. He describes the basement-bed as a soft sandy glauconite,
sometimes containing hard blocks (‘roches’), with nodules of
phosphate of lime perforated by lithodomous mollusca, from 1 to 2
metres thick. This bed is very rich in fossils, the commonest being
Ammomtes Mantel, A. varians, Pleurotomaria perspectiva, Pl.
Mailleana, Ostrea conica, O. serrata, O. Lesueuri, Spondylus striatus,
thynchonella compressa, ete,

From this description there can be no doubt that he takes the

1 Bull. Soc. Géol. de Normandie, vol. vi. (1880) p. 380.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 121
base of the Cenomanian at the bed of sandy glauconitic marl, which
contains black phosphates (see p. 119), and in this we entirely
agree. There is here a well-marked plane of division, for the phos-
phate-bed is separated from the marl below by a seam of sand, full of
glauconitic grains, a rich brown in the centre, from 2 to 3 inches
thick. This brown sand was noticed in all the sections between
Cape La Héve and St. Jouin, except at one place, about a mile east
of the lighthouses. The soft marl forming the bed itself is full
of glauconite, the grains being large as well as abundant; small
quartz-pebbles are not uncommon, and the black phosphatic nodules
are not unlike those of the Cambridge Greensand; indeed, an analysis
by Berthier quoted by M. Lennier shows that they contain 57 per
cent. of phosphate of lime. The following is a list of the fossils
collected by one of us from this nodule-bed; a few marked L are
given on the authority of M. Lennier, and we are indebted to
Dr. G. J. Hinde, F.G.S., for naming the sponges and polyzoa:—

Porirera.

Trematocystia siphonioides, Mich.
@ Orbignyi, Hinde.
Corynella rugosa, Hinde,

, Sp.

ay Aviornn consobrinum, d’Orb.
—— plicatum, Hindle.

Jerea, sp. (= Siphonia).
Pachypoterion compactum, Hinde.
Stauronema Carteri, Sollas.
Plocoscyphia (?) fragments.

Hyprozoa.
_ Porosphera urceolata, Phil.

ANNELIDA.

Ditrupa difformis, Lam.
Galeolaria plexus, Sow.

EcuHINODERMATA,
Cidaris vesiculosa, Goldf.

, Sp.
Discvidea subucula, Klein.
Goniophorus, sp.

Salenia, sp.

Pseudodiadema ornatum, Goldf.
Benettie, Forbes.
variolare, Brongn.

‘L Holaster subglobosus, Leske.

Pouyzoa.

Ceriopora (Ceriocava) mammillaris,
d’Orb.

Diastopora, sp.

— -, 8p.

Alecto, sp.

Melicertes compressa, d'Orb.

Sparsicava irregularis, d’Orb.

FRadiopora (Domopora) tuberculata,
d’Orb,

Potyzoa (continued),

Radiopora ornata, d’Orb.
Micrvpora, three species.

BRACHIOPODA.

Rhynchonella dimidiata, Sow.

convera, Sow.

Grasiana, d’Orb.
Megerlia lima, Detr.

L Terebratula biplicata, Sow.
Terebratella pectita, Sow.

L Terebrirostra lyra, Sow.

LAMELLIBRANCHIATA,

Exogyra conica, Sow.
Rauliniana, d’Orb.
Ostrea canaliculata, Sow.
Lesueuri, Sow.
carinata, Sow.

Pecten asper, Sow.
Duiempliana, VOr»b.
Neithea quadricostata, Sow.
Spondylus striatus, Sow.
Trigonia spinosa, Ag. (non Park),
Cyprina, sp.

GASTEROPODA.

Avellana cassis (?), d’Orb.
Natica (like gaultina).
L Pleurotomaria Mailleana, d’Orb.
perspectiva, Sow.
Turboidea, sp.

CEPHALOPODA.

Ammonites Mantellz, Sow.
navicularis, Mont.
varians, Sow.
Scaphites equalis (a fragment).
L Nautilus subradiatus, d’Orb,
Turrilites, sp.

122 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

It will be seen that the contrast between this fauna and that of
the beds below is very great. It is the incoming of an entirely
new set of fossils, and the presence of Stawronema Carteri is a strong
confirmation of the view which at once impressed itself upon us that
the bed corresponds to the Chloritic Marl of the Isle of Wight.
Almost all the brachiopoda and mollusca occur in our Chloritie
Marl, though most of them occur also in the highest bed of the
Upper Greensand near Warminster, which is part of the so-called
*zone of Pecten asper.’ The relations of this zone in England to the
French Cenomanian will be discussed in the sequel.

What we desire to point out in the present connexion is that in
the cliffs near Havre there can be no question where the Cenomanian
fauna commences: that it comes in suddenly with a bed which
resembles our Chloritic Marl, both in its mineral composition and in
its fossil contents, and in its included phosphatic nodules. Above
this bed there is no break whatever, and, though the material of the
overlying beds is different from that of our Chalk Marl, these beds
pass up gradually into a true chalk near the top of the formation,

Bed 6.

At and near Cape La Heve the phosphate-bed is succeeded by beds
of soft marly and glauconitice chalk, divided by layers of a peculiar
kind of siliceous stone. Examination of this stone proves it to be
permeated and indurated with colloid silica, the condition of the
material being in every stage from merely hardened chalk to a blue-
grey siliceous mass, like the immature chert occurring in the Chalk
Marl of Wiltshire, and described by us,’ while here and there it is
concentrated into nuclei of pure crystalline silica. The result at
this horizon is not definite chert or flint, but ramifying masses of
siliceous material, passing in places to clear black or grey-coloured
chert or flint, without any definite rind.

These beds are discontinuous, and there is a good deal] of variation
in the succession of chalk and chert, even in sections a short dis-
tance apart.

Between these hard beds the chalk is soft and marly, sometimes
firm, but it always contains much glauconite in grains of rather
small size compared with those of the Chloritic Marl. The hard
beds gradually become less marked, and separated nodules or beds
of chert begin to appear.

The incoming of the cherts at La Heéve is marked by five courses
of exceptionally massive character, and these form a striking feature
in-the cliff-face. A little east of the lighthouses the lowest line is
34 feet above the base of the Chloritic Marl, but nearer Havre it is
only 27 feet 6 inches above it. |

Above and between these cherts to the top of Bed 6 the chalk is
of a pale yellowish-white colour, firm in character, and rather

1 Quart. Journ, Geol. Soc, vol. xlv. (1889) p. 403.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 123

rough or gritty to the touch, and it contains less glauconite than
that below.

Grey or black cherts in separated nodules continue to occur either
scattered through the chalk or in lines at irregular intervals.

The bluish colour, probably due to argillaceous matter deposited
with the chalk, gives place very irregularly to the yellowish-grey
which is the characteristic tint of the French Cenomanian. Some-
times it extends up for 12 or 14 feet above the basement-bed, some-
times only 3 or 4 feet, and in one section near Havre the colour does
not reach the Chloritic Marl.

St. Jouin.

In going to the eastward some of the features just described as
occurring at the base of the Cenomanian become lost, and the section
seen at St. Jouin is somewhat different from that at La Heve. The
- Chloritic Marl, with the brown sandy seam and phosphates, is the
same, but the succeeding siliceous beds have died out and are re-
placed by yellowish-white chalk containing comparatively little
glauconite, and in this are lines of thin-skinned black cherts, Above
this the rock for a short distance has a bluish cast.

Near the top of Bed 6 there comes in a course of grey gritty
limestone, with green-coated nodules, much resembling the Tot-
ternhoe Stone of Norfolk and Suffolk. Still farther east, at Brunval,
this bed thickens and is divided into two layers, separated by
grey, glauconitic, gritty chalk. A marked bed of massive chert
immediately beneath this can be followed by the eye from St. Jouin
to Brunval.

This hard bed thins to the westward and is lost before Cape
La Héve is reached. We believe, however, that the massive chert-
bed which just underlies it is at about the same horizon as the
five massive chert-beds at La Heéve.

M. Lennier has minutely described the section seen at St. Jouin
in an account published in 1884 of an excursion of the Société
Géologique de Normandie to St. Jouin, Brunval, and Antifer. He
~makes the thickness of the Cenomanian at this point to be 118 feet
7 inches, which nearly coincides with our own measurement of
119 feet 6 inches. But his section does not appear to include the
basement-bed, so that, if this be added, his estimate will be somewhat
greater than ours. We here tabulate for comparison the section of
St. Jouin as taken by M. Lennier and ourselves, some of Lennier’s
beds being grouped to save space.

124 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

Hitt, 1895. | Lennier, 1884.

Feet. Feet.
Firm whitish chalk with layers Compact grey chalk with nodules
of chert nodules, about......... 20 of bluish chert in layers ...... 113
Bed 8. { Greyish-white chalk divided into Yellow or grey chalk, sandy,
| beds by layers of chert-nodules, with layers of chert and black
| bluish-grey in colour............ 15 AIM asses = see eeteeeeeneensonsecees 26
Grey glauconitic chalk, with hard Grey chalk with layers of cherts
Bed 7 calcareous masses and some and many brown nodules ; this
eee cherts—many brown phos- bed is very fossiliferous ...... 10
qoliatic miodmles) [5-2 seseconnat sent 10 a :
( Greyish-white chalk, slightly Grey glauconitic chalk with
glauconitic, with layers of grey chert-nodules and layers of :
or black cherts ..........0...0005 24-30 black flint ... 022 .cessaeeee ae teeees 32
Hard, grey, shelly, glauconitic Hard, grey, sandy chalk in two
chalk, with hard erystalline beds with a course of sandy
lumps. and _— green - coated glauconitic marl between ...... 10
THOME ere eeee ae ctia sien sinks ewes 8-10 Thick band ofmammillated flint. 1
Bed 6. < Conspicuous layer of cherts.... 3% Yellowish chalk, with irregular
Yellowish-grey chalk divided layers of chert and beds of grey
- into beds by courses of chert- sandy chalk ...... ett eeeeeeesees 2 6
nodules, bands of bluish-grey Bed of large black fli ES) Weawen es 9 in,
chalk at intervals ............... 28 Grey glauconitic chalk............ 9 in,
Bluish-grey glauconitic chalk ... 3 Siliceous bed ............... veveeveee Qin,
Yellowish-grey chalk with four Sandy glauconitic marl with sili-
{layers of black cherts ......... 5 ceous concretions, thickness
Bed 5 Bluish-grey, glauconitic, sandy unknown,
‘Blew marl, with black phosphate-
Marl nodules at the base ............ 3S
* | Thin seam of brown sand, about 2 in.
Bed 4.
The } Bluish-grey sandy marl, seen for 6 or 8 feet.
Gaize.

We were unable to see the marly seam which is taken by
M. Lennier as the summit of the Cenomanian at St. Jouin; our
measurements were taken to the base of a nodular bed having the
unmistakable character of Melbourn Rock. There was apparently
no representative of the marl with Belemnitella plena at Brunval.

It will be seen, on looking at the diagram facing this page, that
above the hard bed at St. Jouin, and above the massive cherts at
Cape La Héve, the Chalk has the same general facies, and the same
description will apply to both.

Bed 7.

About 35 to 40 feet above the massive and conspicuous layers of
chert at La Héve, and about. the same distance above the marked
hard bed described in the section at St. Jouin, there is a band of
chalk containing many scattered phosphatic nodules of a brownish
colour. These are most numerous between the chert-beds, and the
chalk between them is often very glauconitic, rough and gritty to
the touch. The phosphates do not occur with much regularity, and
are more conspicuous at some points than at others. Beyond the
fact of their occurrence there is no lithological break; they come
in with chalk containing more glauconite than usual and pass away
again in about 15 feet. Many fossils occur in this bed, but there

[To fuce p. 124.

Quar
La Hivr.
Ft. In.
beds.
30 to {
MELBO
Roci
0 dey or Greyish- white chalk, with scattered cherts
A jrown and brown phosphatic nodules.
1 (ering
oa
huous
hert-
3 Ghos-
2 | Whitish-grey, slightly glauconitie chalk,
1 (reous eee ei courses by grey aeepe
ear the top are two marke eds of
2 \ ze 00 black cherts. :
>
5 ¢ erts
1 thert-
oncre-
B.. (
hard
herts. Yellowish-grey, slightly glauconitie chalk,
o EBrey: 13 0 wage Le divided into courses by chert-beds.
1 cps. ODoS0 9p
2 yer of S0oDScoO
4
herts, : ie =e
re Yellowish-grey glauconitie chalk, divided
8 0 into courses by five beds of massive
5 ¢ cherts.
lvided :
Yellowish-grey, slightly glauconitic chalk,
9 0 with scattered cherts, divided irregu-
larly into courses by hard siliceous
layers or beds.
Ban Beds of chalky material, indurated with
silica, separated by courses of marly,
14 9 very glauconitic yellowish-grey chalk.
& yi grey
elow, Firm yellowish-grey glauconitic chalk,
5 0 with hard siliceous masses like imma-
lines ture cherts.
! Wh Bluish-grey, very glauconitic, sandy marl,
black 6 0 CHANGE ADESSO with hard masses and many black phos-
AGRO tp phate-nodules.
UPP \\ Sandy seam.
ER Bluish- , sandy, gl iti 1.
Gaatka ben \ uish-grey, sandy, glauconitic mar

(GaIZE).

Quart. Journ, Geol. Soc. Vol. LIL.
[To fuce p. 124.

SrcTions or THE CENOMANIAN AT Bronvat, Sr. Journ, anp La Hive.

(Scale: 1 inch = 20 feet.)

Bau Sr. Journ. Ta Thivr,
Abit, © 00°00 \ Ft. In.
ee eee ‘Ft. In.
S2200K5 F
Om C2006 oo 534
Seraccos . .
Greyish-white firm chalk, divided into courses by la iti ividedi
ee Ssceese of separated, thick-skinned, bluish-grey cherts, rl baya ye Whitish-grey chalk, divided into courses by chert-beds.
Rock. 9e20304 this.
2S9a02000
10 Grey marly chalk.
09 qioueunitie marly chalk. Grevishawhite jalightivel itio chalk, with Gravion h
re auconitic chalk, with reyish-white, slightly glauconitic chalk, wi or reyish-white chalk, wi 5 :
Pa bra eioaihater Seman, sHentieredeberta eae wk black cherts roared and in lines, nestorn and brown phosphalg nent nee
1 0 Marked line of cherts. phosphatic nodules.
70 Grey glauconitic chalk, with hard masses and separate ess Grey chalk, with hard concretionary masses weathering
cherts, large and small. Brown phosphates. 20 out.
3 6 Whitish-grey glauconitie chalk, with hard concre- Greyish-white glauconitic chalk, with discontinuous OO OTOTO CS
tionary masses. Theo beds of black cherts, the chalk separating the chert- eee
26 Grey, slightly glauconitic chalk, with scattered cherts, beds being grey and more glauconitic. few phos-
phates at top. Thigh .
1 6 Line of large cherts with black centres. ; ¢ Whitish-grey, slightly glauconitio chalk,
23 Firm glauconitic chalk, with hard concretionary masses, 26 Yellowish-grey fmlenconiits chalk, with hard calcareous guided ants sae by Brey cherta,
5 . 2 op ar vi rke
5 6 Hoan Brey Blsuconitie chalk, divided into courses by ae tk ae erts iehiwrl ‘ao dhalk= here ot black crores ti dares s1S CH EH
eds of prey cherts. irm yellowish-grey, slightly glauconitic chalk; cherts
Cua 5 6 scattered amiga lines,
10 Hard chalk, weathering prominently in the cliff-face.
Yellowish-grey glauconitic chalk, with marked chert-
8 6 Whitish-grey, firm glauconitic chalk, divided into 7 3 bed, scattered blue-grey cherts, and hard concre-
courses by layers of black-centred cherts. tionary masses.
Hard bed, composed of crystalline lumps cemented to- ae see ee naosbovehals, Perea ct,
gether in ashelly matrix; green-coated nodulesattop, Firm greyich-white chalk, with scattered blue-prey 13 0 rt einme d T ca e

Grey, gritty, shelly glauconitic chalk.

Hard grey crystalline lumps, cemented by shelly
matrix; green-coated nodules at top.

Whitish-grey chalk, with line of scattered cherts,

Massive cherts.

Smooth whitish-grey chalk, with lines of small cherts.

Firm, grey shelly chalk, with hard crystalline lumps.

Hard, irregularly crystalline chalk, with a layer of
green-coated nodules at the top.

Firm grey glauconitic chalk, with two lines of cherts,
the lower very massive. 8 0

oe wht ow ww
On IS On esac

Yellowish-grey glauconitie chalk, divided
into courses by five beds of massive
cherts,

Yellowish-white, slightly glauconitic chalk, divided
into courses by chert-beds.

Blue-grey marly chalk, just seen above beach.
Yellowish-grey, slightly glauconitic chalk,

13 0
9 0 with scattered cherts, divided irregu-
larly into courses by hard giliceous
layers or beds.
10 f=———=ss) Blue-grey marly chalk, weathering in thin lamine.
Oo Vco 20)
ibe eo ae =)
Perse (eta | F pan . i Beds of chalky material, indurated with
’ ; Yellowish-grey chalk, divided into courses by lines of ds y \
10 0 linia acd i) cherts, ae broadly streaked with bluish-grey. 14 9 Sree Separated by course ot mr
IPRA AUTH eh
SOD O0 Ss
NU aL

Firm yellowish gray glauconitic chalk,
with hard siliceous masses like imma-

cu } Bluish-grey marly chalk, more glauconitic than below, Aen
1

{alll
3 6 i
ny ith hard eretionary masses.
oe with hard con ‘vy with hard

l

Sigisin soe . .
e o a
5 0 aeteeraeer Mellons ted alia civided inte pourgoaiby toby lings ean Blnleh- ray, very glauconitic, sandy marl,
Blue-grey, very glauconitic, soft sandy marl, with black Mistetednihe ses and many black phos-
oe phosphatic nodules. P .
UPPER Sandy seam. Ae Sandy seam, F
GREENSAND Bluish-grey, sandy, glauconitic marl. UPPER Bluish-grey, sandy, glauconitic marl.
(GArzE) GREENSAND
: (Gaize).

: Yo oe, :
Fee Pe CMT RO ui RT

‘
A e ‘ ie cme |
\ ay Se 7
i i
; i
o 4
/
‘
Uae f yal ‘
¥! ' '
i
ae m 4 *
Rare ANY Lite ens 1] ‘
“y a i
~! — 4
; TW cine
! F é
Beer eas het weve t
ms tg ty
’ sg ae yee es
WP BD S Atte se aed 7h !
MN ;
dn eS Fins: a
+ -
Whi ays, 4
Tet hia: Pe Ran eng het
, t j
ne ort a4 hm & A ‘

of \ car rh ; , wel ere

. je j , ne i ar , ¥ hiya x
; nce) ee } eg CAL x
: ) 4 4 : Ce eae 4)

+

fy
fa ER aaaRmREIAE 6)

? yen oe Ce

~
he
6

; Ses rea ’
+e f ee ah a 7 ‘
\
‘
i
*
h
|
a f
}
' u
‘
5
i Ls

Wol. 5am ‘A DELIMITATION OF THE CENOMANIAN, 125
is little difference between its fauna and that of the beds below.
Cephalopoda are rather more abundant, but are of the same species ;
Holaster subglobosus becomes common ‘about 8 feet below this bed
and ranges above it, at the same time Epiaster crassissimus and
Catopygus carinatus either die out or become rare. The following
is a list of the commoner fossils occurring in this central part
of the Cenomanian, the first column showing those in Bed 6, and
the second those in Bed 7. The letter L indicates species which are
given on the authority of M. Lennier :—

o | CIS
ro \o ro |
eal fas 3 |e
SEEROS PVE, Sep aicdnyinaene «cine anns * Ostrea canaliculata (lateralis) ...| x | *
9% UG COWOLE, a ndisssessae * DEC CLO MES Clay ahs sewipivcianecn dy sreaoos * | *
Rhynchonella convexd .......0004. * | * el MON COUT owe Se eo dase recon *
ua dimidiata ......... % | x ig PM GrrOTORUS Wocsksiecwcnn tees *
se GTAStANA ...c00ee. * | % Ral Y EGC OSIOWUS (ysis wbigbetsee celal *
TOHGEND WME 5... ocvcousenstesven« % of CLONGOTUS'. & wtqcrgarogad cent *
Terebratula arcuata .......0.e000. % SANTE, CQUWICOSLALA ...nacevevcaene|aoe *
COPUIGIE, “cipcntanene= * 39 (WINUCCOSEALA «2.00. 00000: % | %
Terebratella Menardi .........00.)++- * || Lima clypetformis..........cececee- L
Caratomus rostratus .......eeee000. L| x || Spondylus striatus ............00- x
Catopygus COTINAtUS ......000.0000 % Pleurotomaria Archiact ......... L
Cid aris VesiculOsa, .......secevsecees 1% || AVCHANA CASSIS cas.cebaceaseres coast leae L
Hlolaster Carinatus. .cccccccccccocses ¥ ADOTFNGIS) SP; CASb. .scceesneeods|ace *
dp), , SUPGIOBOSUS 2). caisese cate *|%|| Ammonites falcatus .......c.0.000e lee. L
Epiaster Crassisstmus ..s000-.00+- * DNGREM) . nv ssnscnds *|L
Pe GUSTINCLUS). “FS. .c den osaak L i COT UUNS. ett snadaeads es % | %
Pseudodiadema ornatum ........- % | % kf COUP CH. ksh cedacecbenas * | *
Benetti@é ......... x VUPTIUECS COSLATUS ... occeoesenn * | %
Discoidea SuoUCIG 2S SI! * | * uF tubercwlatus ......00000. % | *
Glyphocyphus radiatus..........+.|..+ * || Scaphites equalis .........s.ce0eee- cite
Salenia petaliferd .....ccs.cecsecees iG SAS ELA MORES SOON ctsa «02s oh can ac aoe neal 12. %
is BW, ssueces sates seed sialeses's * INGUIDUUS ISS fa chocnnenskseaicivanda~vs|'ans *
EDOGYTE CONCH 5 s0.6sccidcineseesses % |
Bed 8.

Above the phosphates the chalk is featureless. It is, however,
distinctly whiter and more free from glauconite; flint-like cherts
continue to divide it into courses. Fossils are comparatively rare-;
we collected none from it,

The Turonian.

The base of the Turonian is well marked between St. Jouin and
Brunval by a bed of hard nodular chalk, like that which we
recognize in England as the Melbourn Rock. In fallen blocks on
the shore fossils common to the base of the Middle Chalk occur
plentifully, such as: Jnoceramus labiatus, Rhynchonella Cuviert ,
Cardiaster pygmeus.

126 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

LY. A CoRgrELATION OF THE CENOMANIAN DEPOSITS IN THE
CaLvapos, ORNE, AND SARTHE.

1. Calvados.

Having studied in detail the sections of the cliffs at and west of
Cape La Héve, and having satisfied ourselves how much of the series
corresponded to our Gault and Upper Greensand, and how much to
our Lower Chalk, we desired to ascertain the stratigraphic relations
of this combined Albien and Cenomanian series and that of the
typical Cenomanian in the Orne and Sarthe.

This was a more difficult task, because no French geologist had
explored the ground for this ‘special purpose, consequently the
exposures had to be sought for. Sections in the middle and upper
part of the Cenomanian, such as occur near Honfleur, were of no use
to us: what we required were exposures of the basement-beds, in
order to judge how far the Havre equivalent of the Upper Green-
sand extended to the southward, and whether the base of the
Cenomanian continued to present the same character as that ex-
hibited by it at Havre.

We soon found that it did not, for the following section was seen
at Moulineaux, about 2 miles 8.S.W. of Honfleur, in a pit which
had been recently dug in the side of a hill for the formation of a
washing-place or reservoir. Descending order :—

; Feet. Ins.
Soil, chalk-rubble, fragments of chert and
brownish Clay access «micas nisiene eaRuneeecs 8 0
(3. Yellowish-grey, soft, marly chalk, very glau-
| conitic, and containing hard siliceous concre-
tions, also many fossils: Rhynchonella dimi-
CENOMANIAN. 4 diata, Rh. Grasiana, Megerlia lima, Ostrea
vesiculosa, spines of Cidaris vesiculosa ...... 4 0
2. A bed of hard masses in soft grey and very
glauconitic marl, with Ph. dimidiata, Cato-

PYGUS COLUNGUUS OUCH seas ema saeennnee 2a s6/ae-ce Ke 3. 38
UPPER 1. Dark grey, exceedingly glauconitic, calcareous
G-REENSAND. marl, seen fore reeceee reece ence cee cieteaes 23 0

The material of Bed 2 resembles that of the Chloritic Marl of
La Heve without the phosphates, the glauconite-grains being large,
but the cementing-material of the hard masses proves to be calcite.

The overlying chalk is similar to that occupying the same
position near Havre, its glauconitic grains being small, and we
think there can be no doubt that the base of the Cenomanian was
here exposed.

Passing to the valley of the Touques and proceeding by the
high road leading from Pont l’Evéque to Lisieux, the next exposure
noted was about 200 yards east of Les Forges, on the road leading
to Blangy. Here a strong spring is thrown out, and yellowish-grey
glauconitic chalk was shown just above it, while on the other side
of the road a freshly-cut ditch showed grey and very glauconitic
marl, but without hard lumps similar to those of the beeen
near "Honfleur. : :

Vol. 52.] ‘A DELIMITATION OF THE CENOMANIAN. 127

Blangy lies in a branch of the main Touques Valley. On the
southern side of this valley, along the high road leading to the
village, the outcrop of the Upper Greensand was evident in many
places, but no good section was seen.

On the northern side of the valley the hills are more precipitous,
and there occur several small pits in the basal part of the Ceno-
manian. In one of these yellowish-white glauconitic chalk was
seen passing down into yellowish-grey marly chalk containing much
glauconite, and in a small exposure 30 yards to the west this was
seen to be underlain by grey calcareous marl containing much
glauconite in large grains. Farther on, several small exposures in
the bank showed this calcareous marl passing down into a green-
sand. There was no complete section, and no hard lumps were
found, but it was evident that the Cenomanian passed down through
a bed of marly glauconitic chalk to the greensand. Returning to
the main road, the grey marl and glauconitic junction-bed were again
seen in a ditch about 3 miles north of Lisieux.

At the village of Hermival, which lies in another minor branch of
the Touques Valley, the Upper Greensand was well seen, by following
a newly-cleared ditch by the side of the roadway, passing up into a
grey glauconitic marl, at the top of which was a bed of hard
crystalline lumps between 1 and 2 feet thick; this was overlain
abruptly by yellowish-grey glauconitic chalk. A small spring
seemed to issue from the junction of the two beds.

About 13 mile south of Lisieux, just before coming to the
village of St. Martin de Liette, is an interesting exposure in a large
sandpit, which shows that the Carstone-like bed at the base of the
Gault, to which we have drawn attention in the section of the cliffs
of La Héve, persists thus far, though somewhat attenuated. The
section is as follows :—

Feet. Ins.
Rubble of grey chert and sandy soil ...............46. 2 0
Very glauconitic and rather marly sand ............ 2 6
Wark: preys precast Clay, sit cash on dain seigaeeaoninejnam setint Soe Qh nD
Coarse brown pebbly grit, with much fossil wood
and many light-coloured phosphates ............ 7 0
White micaceous sand ..............scceseseceees about 40 0

The white micaceous sand is part of the ‘Sables de Glos’ (Corallian),
On this rests the coarse brown grit, which is succeeded abruptly
by the clay. We found no fossils in either, except the cast of
a Natica in the brown grit, about 18 inches from the top; but
M. Bigot, of Caen, informed us that he had found others in the
same bed, and kindly sent them to us for inspection. Most of
them showed a matrix of very glauconitic material, and we think
that they have come from the very top of the grit (or Carstone) at its
junction with the clay. Among them we could identify Ammonites
interruptus (vars. Deluc and dentatus), Pecten orbicularis, Cucullea
fibrosa?, and a large Cyprina or Cucullea. There was also a
Natica in a brown matrix, like that of our own specimen, The

128 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

ammonites are sufficient to prove the bed which yielded them to be
of Lower Gault or Albien age.

From Lisieux, acting under the advice kindly given us by M. Bigot,
the country south-east of the valley of the Touques, in the neigh-
bourhood of St. Paul de Courtonne and Orbeec, was next explored.

At La Haute Roche, about 3 mile 8.8.H. of Courtonne du Murdrac,
the following section was seen :—

Feet. Ins.

Yellowish-grey chalk, slightly glauconitic, scattered grey
cherts and ramifying siliceous concretions in discon-

LIMO MER DEA Se LEI secs. ck SERRE Stee vac ceive oak denn th ocd Boke’ 4 0
Chalk similar to the above, with two beds of massive chert... 2 6
Yellowish-grey chalk, glauconitic, with scattered cherty or

BinGe@uUs COMCKELOMSS ates caer. aetrentcrne. ie secie oilers ace’ siemens 9
Yellowish-grey chalk, firm, slightly glauconitic, with large

cherts arranged in discontinuous lines ................cec0e 10 tae
Mealy, yellowish-grey, very glauconitic chalk, seen for ...... 1 6

This exposure occurs in a low cliff capping the summit of a hill,
and is not far from the base of the Cenomanian, which was estimated
to be 12 or 15 feet lower than the bottom of this exposure. About
this vertical distance glauconitic sand was well shown in the hedge-
row and in the field below, the base of the Gaize being probably
indicated by a spring and the boggy nature of the ground ; if this
surmise is correct, the Gaize and Gault cannot be much less than
30 feet thick at this point, and may be more.

The section can be followed for some little distance, but the
junction-beds were not noticed.

About 300 yards 8.S.E. of the church of St. Paul de Courtonne,
13 feet of whitish-grey, slightly glauconitic chalk was seen, with
discontinuous lines of grey chert, and 30 yards farther on there
was a course of hard, grey, lumpy chalk with many fossils, about
2 feet thick, making with the other a continuous section. The
ground then dropped suddenly, forming a steep pitch, a feature
constantly noticed at this horizon in many localities in Calvados,
and below this it sloped gently to the banks of a brook some
50 yards away.

The soil was full of large glauconitic grains, evidently Greensand.
A little farther S.E.,in the next field, along the steep pitch of
the ground already noticed, were many hard calcareous masses
full of glauconite and of the same character as those of the junction-
beds at Honfleur and Hermival, but the glauconitic grains were
smaller. About 2 mile farther S.E., opposite the turning of the
road to Orbec, many specimens of Pecten asper occurred in lumps of
hard chalk scattered along the top of the pitch, the material
adhering to them being yellowish-white, slightly glauconitic chalk,
not like the basement-bed which was seen in the banks of the brook
4 or 5 feet lower. | |

The basal beds of the Cenomanian were again shown about
300 yards east of the Chapel of St. Julien de Mailloc, in a small pit
in a field, The section was as follows :—

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 129

; Feet. Ins

Henbbly Brokemehallk and. sOW. ......: coin. s0o0scorccasarsoesene 6-7 0
Smooth glauconitic chalk in two massive beds, weathering

with a peculiar mealy touch when handled ............... GH

Rough, lumpy, grey, glauconitic chalk, hardly nodular, but
lumpy, the lumps being hard, with soft mealy chalk
BEINEEO. VOrY SOSSLILCTOUS .(o cmnasee cc socsnecanaedednncaes cess 6 6

At or near Orbec are several large pits at this horizon showing
the lowest part of the Cenomanian, but without exposing the actual
base. The most important is a quarry close to the railway, halfway
between the stations of Orbiquet and St. Martin de Bienfaite.
Nearly 40 feet of chalk is here exposed and its general character
may be understood by the following section. Descending order :—

Feet. Ins.
Smooth, yellowish-grey, mealy chalk, rather glauconitic... 2
Rough chalk, lumpy, the lumps being in a mealy matrix . 2
Soft, yellowish-grey, mealy chalk with grey cherts ......... 7
Rough, glauconitic, yellowish-grey chalk with hard lumps
in a softer mealy matrix ........ Ash asecaacbw th mete sade a aakite
Firm, glauconitic, yellowish-grey chalk..................0.000
Firm, glauconitic, yellowish-grey chalk, with hard silicified
MAS ES == TIOL CHEN Dees eraser ce one sec an cca emon vc noaduideece sce ce
Softer glauconitic chalk, weathering in platy pieces......... 2
Bed of large separated! chert) 10-2 ..6..00d.ohiscesesasteewse-adece 0
Firm, yellowish-grey, glauconitie chalk, smooth, without
BUTS eee eee a ators sara seins =v ew sia aime ela sc aoajs aaiceiwniseleiwe deen basicmes
A course of hard, lumpy, glauconitic chalk .................. 3
Smooth, whitish-grey, glauconitic chalk...............cec.cc00e 1

OOo One OO COS

Although the general character of the chalk seen in this quarry
agrees with that at the same horizon in this and other localities, we
are unable to correlate the various beds, and it would appear that
minor peculiarities do not persist in the way that frequently happens
in the English Chalk. The rock at this horizon is usually yellowish,
or ochreous white, or grey in colour, slightly but irregularly glauco-
nitic, some beds containing more glauconite than others, the grains
being small. It weathers down and gives off a dust which has a
somewhat gritty, mealy texture, and is not the impalpable powder
which results from the handling of English chalk.

It contains many concretions of a siliceous nature, sometimes
merely silicified chalk; but often there is a nucleus of clear black or
grey silica, which merges through the silicified chalk into the calea-
reous matrix which surrounds it, there being norind. Well-defined
chert-nodules are, of course, also common.

2. Northern Orne.

Continuing the exploration of the Touques Valley, evidence of the
outcrop of the Greensand was met with in several localities, but no
section was seen until Fauvaque was reached. Here a small quarry
showed Greensand still underlain by a thin bed of clay, which in
its turn rested directly on the Corallian—the Carstone-like bed being
absent,

130 MESSRS. A. J. JUKES-BROWNS! AND W. HILL: [May 1896,

A mile north of Notre Dame de Cou’son a new section in a road-
cutting was fortunately seen, showing about 9 feet of soft, exceedingly
glauconitic sand, and about 100 yards north of this the section was
carried higher in the bank of a short cutting in a lane. Here there
occurred about 2 or 3 feet of greyish calcareous and rather marly
sand with rusty markings. It contained many fragments of Pecten
asper, and the material was very similar to that found at the summit
of the Greensand at Vimoutiers, 6 miles southward. No hard cal-
’ careous masses were seen, but we think that this grey calcareous
marl was undoubtedly the top of the Greensand.

Vimoutiers was the next place of interest, and we have heartily
to thank M. Lecceur, of this town, for his kindness in accompanying
one of us to the principal sections in the neighbourhood, and also for
his generosity in adding some named specimens to our collection of
fossils. Nowhere else was the whole Cenomanian so well shown as
in the large quarries near here, which give almost a complete section
from the Greensand below to the Craie marneuse at the top. Besides
this, continuous railway-cuttings enable one, armed with proper
authority, to study the upper part of the Cretaceous series far above
the beds in which we had especial interest, and one could not help
regretting that time allowed the study of the basal portion only. The
following section was taken at a very large quarry, nearly a mile
north-east of the church :—

Feet. Ins,
( Soil, eb, .ccseeseeeececseseeeseeseeesaeeeeseseeeeesees 1 Lv)
Greyish, glauconitic, sandy chalk weathering

to mealy dust, rather harder rough rock

alternating with smoother layers, cherts

scattered or in discontinuous lines ......... 37 0

Yellowish-grey, glauconitic, sandy chalk,
rough, with hard irregular lumps (not

nodules), softer chalk between .............5- 6 0
Massive grey cherts, apparently a continuous
DOG occas cnc eee eetee Remnant Selene oisc rerteinrster 1 0

Yellowish-grey, glauconitic, sandy chalk, rough
Crnomanian. { and lumpy, softer mealy chalk between the
TRUIADS |. bcos. a eeemamneeeeete eps ceeuradeteie tere anlar 1 6
A line ah separate@seherts . 0. ...-.2-caccseonssaese OF ae
Yellowish-grey sandy chalk, rather glauconitic,
with lighter patches, massive cherts irre-
gularly scattered—passing down to ......... GO i
Yellowish-grey, rather soft, mealy, and very
glauconitie sandy chalk containing hard
SiliceOUs CONCEELIONS) (7 .q.cccns.-s50+-ecs0nences 6 60
A bed of detached, hard, calcareous masses,
very glauconitic, forming a marked hard
) MaYeY ...-2..c0secemecnsacndenesnronertsesconseceeoees 1 0
Greyish-green, very glauconitic, calcareous,
sandy marl with rusty markings, passing
down to dark green glauconitic sand, which
gradually became darker and was almost
black at the baseiy..6.cs.scesetess oe dvedtat otek 10s, a8

UprEr
GREENSAND.

The Corallian immediately underlies the Greensand, but the actual
junction is not seen in this quarry.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 131

The line of separation between the Cenomanian and the Greensand
is sharply marked, and the lithological difference between the two is
striking. The one is a yellowish-grey, slightly glauconitic chalk,
the other is a green marly sand in which large grains of glauconite
preponderate, and even at the top, which is most calcareous, they
give a distinct greenish tint to the deposit. This green sand is so
soft that it can be dug with the fingers.

No fossils of any kind rewarded a search in the Greensand, nor
was the base of the Cenomanian very fossiliferous. Many of the
cherts and siliceous masses were evidently sponges, too bulky to
carry away.

Most of the section given above is in the zone of Ammonites
Mantelli; the highest part of this zone, with the overlying Craie de
Rouen, or zone of Ammonites rotomagensis, and the Craie marneuse
is seen at the quarry at Lisores, about a mile north-west of the
railway-station at Vimoutiers. About 40 feet of fine-grained, glau-
conitic, sandy chalk of the upper part of the zone of Ammonites
Mantel: was here exposed, with courses of rough lumpy chalk,
and cherts, some scattered and some in layers.

The base of the zone of Ammonites rotomagensis is marked by a
bed of intensely hard, creamy-yellow, crystalline, and glauconitic
chalk, containing the usual hard siliceous masses of partly-formed
chert. A series of small pits showed similar hard beds alternating
with layers of soft grey and very glauconitic marly chalk, so soft in
places that it could be almost dug with the fingers. These beds
were in turn overlain by the Craie marneuse, a whitish-grey, slightly
glauconitic, marly chalk not unlike in texture to the top of our own
Grey Chalk.

Thus the whole succession of the Cenomanian seen at Vimoutiers
is as follows, the thicknesses given being supplied to us by
M. Lecceur :—

Feet.
onus ac). Oraile MALNGUSE 525. .c.- pss sdedsceecties-sewmgie ssa «vaso 10-14 ©
ee Craie de Rouen or Zone of Ammonites rotomagensis _ 33
q "| Zone of Ammonites Mantellt 2... .ccsscscacecosssesonoes 113-115
Wipers Greensand x io. Fessdncsetace st tainatasciogelastalce'eneis’ 10

Corallian,

Many of the fossils found in the Craie de Rouen are in light
brown phosphate. We recognize in this Craie de Rouen Beds 7 and
8 of the section at Cape La Heve.

M. Lecceur, of Vimoutiers, has sent us the following list of fossils
collected by him from the Craie de Rouen of that locality and
permits us to publish it :—

Q. J.G. 8. No. 206. L

132 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

List of Fossils from the Craie de Rouen.

Catopygus carinatus. Trigonia spinosa.
Discoidea subucula. Avellana cassis.
Epiaster crassissimus., Fusus Espaillact.
Pseudodiadema variolare. Pleurotomaria, 2 species.
Terebratula biplicata. Ammonites varians.
lacrymosa (ovata). rotomagensts.
Rhynchonella alata (=dimidiata, Scaphites equalis.
Sow.). Baculites anceps ?
Lamarckii. Turrilites costatus.
Ostrea pseudo-vesiculosa. Hamites simplex.
Inoceramus cuneiformis. Nautilus elegans.
Corbis rotundata. carinatus.
In addition to these we have obtained :—
Ostrea canaliculata. Cardium, sp.
carinata. Ammonites cenomanensis.
Janira equicostata. . Turrilites tuberculatus.

The fauna really differs very little from that of the zone of
Ammonites Mantelli, except that in this locality some of the cepha-
lopoda, such as Ammonites rotomagensis and cenomanensis and
Scaphites equalis, do not occur in the lower zone. Elsewhere, how-
ever—for instance, near Havre and in England—Scaphites equals
ranges to the very base of the Cenomanian.

About 1} mile 8.W. of Gacé there isa large quarry where the
Corallian has been dug; a lane leads round its southern extremity,
and here there occurred a complete section through the Greensand
to the zone of Ammonites Mantelli as follows :—

Feet.
Rubble of chalk, cherts, and soil.
Yellowish-gr ey, ‘sandy, micaceous, glauconitic, siliceous
‘chalk’ (more than usually rusty-coloured, probably
CENOMANIAN: 4---- manch-weathered) vsicccc.sse.cercececececactedecreceewesenbes 6-8
A layer of hard, very glauconitic, siliceous, partly
crystalline imassestqeb. mel ce eee ih eatecssonmeemear

Weean | Exceedingly glauconitic, green-grey, sandy marl, passing

ese Gants: dewn to very dark, marly, glauconitic sand, almost

black atthe basemecscntcen ci vccecs. 5 aly scecice Soon 9
CoRALLIAN. aoe

Ammonites Mantelli and A. navicularts occurred in the yellowish
* chalk,’

Near Mortagne, along a field-path leading from Mortagne to
Villers, the Greensand was seen in several places as one passed over
the outcrop, but no section was found.

Near the railway-station at Villers, in a ditch by the roadside
along the road towards Fiengs, it was constantly exposed. Returning
from Villers by the road which joins the high road from Paris to
Brest at La Jarreticre, Greensand was seen in the fields adjoining
the road, and at one point the plough had turned up many pieces
of the hard crystalline bed at its summit.

Vol. 52.] ° A DELIMITATION OF THE CENOMANIAN. 133

Turning towards Mortagne, along the high road, about 3 mile
from the village of La Jarreticre, the Greensand is exposed in a lane
to the left much as it is at Gacé. Its character is the same,—a
light, calcareous, marly sand, passing down to a deposit almost black
in colour. The top is hidden; a wide dark band, visible for
some distance away, betrays its outcrop in the arable fields, over
which are scattered fragments of the hard bed. The estimated
thickness of the Greensand here is 15 feet.

The yellowish ‘chalk’ with Ammonites Mantelli was seen to
immediately overlie the Greensand in the cutting of the road to
‘St. Hilaire les Montagne, about 100 yards nearer La Jarretiére.

From the evidence gained by this traverse we think that after
leaving Cape La Heve a lateral change takes place at the base of the
Cenomanian ; that the bed with black phosphates dies out before
reaching Moulineaux, near Honfleur, and gives place to a bed con-
taining hard crystalline masses; that between Lisieux and Vimoutiers
this bed becomes condensed, as it were, until it forms a small and
well-marked hard layer at the base of the ‘Chalk.’ If we are
correct in this opinion, this hard layer is the true base of the Ceno-
manian, and the beds below ought to be excluded from this stage.

We have seen that the Gault at Lisieux is at the point of disap-
‘pearance, and consequently we take the mass of the glauconitic
sand south of that place to be the equivalent of the Gaize; but, as
Pecten asper occurs in the sandy marls at the top of these, it would
appear that a local or lenticular deposit representing the English
zone of Pecten asper is present for some distance. Whether this
enters into the 10 feet of glauconite at Vimoutiers we will not
undertake to say, but we have no doubt that this 10-foot bed is
the attenuated representative of our Upper Greensand, and that
the beds above it are the equivalent of our Lower Chalk.

[ Note. November 7th, 1895.—Since the above was written we
find that Prof. de Lapparent has expressly separated this ‘ glauconie
4 Ostrea vesiculosa’ of the Eure, Orne, and Maine from the Cénoma-
nien (‘ Traité de Géologie,’ 2nd ed. 1885, pp. 1041 and 1075). He
classes it with the Albien, and considers it to be the equivalent
of the Gaize of the Havre district; speaking of the Cenomanian of
the Orne on p. 1075, he describes it as ‘resting on the glauconie a
O. vesiculosa.’ This was a new departure, MM. Guillier, Bizet, and
other French geologists having always regarded it as the basement-
bed of the Cenomanian Series. It is satisfactory to find that we
had independently arrived at the same conclusion as M. de Lapparent,
-and that, so far as Western France is concerned, we are in complete
accord with his definition of the Cénomanien stage.

He does not venture upon any correlation of the western Céno-
manien with English deposits, but includes the Warminster Green-
‘sand in his table of English equivalents. If, in his next edition,
he were to omit this greensand, his table would express precisely

our view of the subject. ]
| L2

134 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

38. The Cenomanian Sands of the Southern Orne and
Sarthe.

We now come to a region which has been well explored by
Messrs. Paul Bizet and Albert Guillier. The great change from a
chalky to an arenaceous facies begins to set in between Gacé and
Mortagne, and, curiously enough, this occurs at the very top of the
formation, beds of sand coming in above the ‘Craie & Ammonites
rotomagensis. These are the ‘Sables du Perche,’ and it is interest-
ing to find that they contain fossils which we are accustomed to
associate with much older deposits (Chalk Marl and Upper Green-
sand). M. Bizet mentions, as common fossils, Ammonites navicu-
laris, Ostrea carinata, Rhynchonella compressa, with many shells.
of Exogyra conica and EF. columba.

Near Mortagne the sequence is given by M. Bizet’* as follows:—

4, Sables du Perche 4 Ammonites navicularis.

3. Craie de Rouen a Ammonites rotomagensis.

2. Craie glauconieuse 4 Ammonites Mantelli.

1, Glauconie et argile glauconieuse a Ostrea vesiculosa.

The Craie de Rouen is a thick mass of chalk which is divisible
into two parts or zones: (1) an upper zone of Scaphites wequalis,
which consists of alternating beds of firm chalk and greyish marl ;
(2) a lower zone to which he does not assign any particular fossil,
but which consists of chalk with nodules of greyish flint.

The Craie glauconieuse is evidently like that which we have
described at Vimoutiers and elsewhere, but M. Bizet seems to
include in it what we regard as the uppermost beds of the ‘ glau-
conie’ or Greensand. ‘Thus, in his excellent paper on the ‘ Profil
géologique du Chemin de fer de Mamers 4 Mortagne,’ he writes :—
‘Above the greensand come more or less argillaceous marls and
sands, then alternations of glauconitic sand and beds of a kind of
greenish or yellowish chalk, always containing many green grains.”
He classes both these in the zone of Ammonites Mantelli, but we
did not find that fossil in the argillaceous marl, and, as already stated,
for us the base of the Cénomanien is at the top of this marl and
at the base of the yellowish chalk.

Near Mortagne and Belléme the lowest Cretaceous deposit is the
‘Glauconie a O. vesiculosa.’ This is a sandy marl or clay, which in
some places, and especially in the east of the department, contains
phosphatic nodules; its thickness is only from 3 to 10 feet, and
Ostrea vesiculosa is the sole fossil found in it. At Ceton, however,
on the eastern border of the Orne, a representative of the Upper Gault
or Gaize comes in below this ‘ glauconie —a glauconitic clay with
phosphatic nodules and casts of fossils, among which are Ammonites
inflatus, A. auritus, and Arca carimata. Ammonites splendens has
also been found in the same bed at Souancé, near Nogent-le-Rotrou.

It is clear, therefore, that. the Upper Cretaceous sequence in the
east of the Orne is nearly as complete as in the Calvados, and that
it is merely a question as to where the line for the base of the
Cénomanien should be drawn.

1 Bull. Soc, Géol. Normandie, vol. viii. (1881) p. 40, and vol. xi. (1885) p. 58..

vol. 5 2,’| ’ A DELIMITATION OF THE CENOMANIAN. 135

4. Sarthe.

Proceeding still southward, we find that the next change takes place
in the lower portion of the Craie de Rouen, which becomes sandy
and passes into grey sands with blocks of calcareous sandstone.
Thus in the communes of Théligny and Lamnay a mass of such
sand is intercalated between the ‘ Craie a Scaphites’ and the ‘ Craie
glauconieuse 4 Ammonites Mantelli.’ The researches of M. Bizet in
this district have established the following succession :—

Feet,

5. Sables du Perche a Rhynchonella compressa, with Ammonites
PACU ISAM LAG OWIG cyanate ociias sian xenie~ogeeiqnabdaesdaaness +20
4, Craie 4 Scaphites equalis, with Ammonites varians, Turri-
Lites COSIGTUS, BOA PECLEN GSPER...sncsciasecsecsanseseccsanconce 60 to 70
3. Sables et grés a Perna lanceolata et Anorthopygus orbicularis 1380
2. Craie glauconieuse a4 Ammonites Mantelli, Turrilites tuber-

CROSSE COLCINOS POT MEUCH | arPnd te Se med. sad deoaoehateaaueteens hx 80
Poe ATICONTIC, & OSTEO. VESLCULOST, 05a. saautsond eatcacenedesiaesssdes ve 25
+325

Finally, towards the south-west, in the direction of Le Mans, the
«Oraie a Scaphites’ also undergoes a lateral change; beds of sand and
sandstone set in, and the chalky marls thin out, till the whole is
replaced by sands of various colours, grey, green, and yellow,
enclosing large blocks of calcareous sandstone. These sands have
yielded a large number of fossils, the numbers known to M. Guillier
in 1886 being, of mollusca 200 species, of echinodermata 30, of
bryozoa, corals, foraminifera, and sponges over 130 species. The
larger number of d’Orbigny’s types were in fact obtained from this
portion of the Cenomanian series.

The ‘Sables a Anorthopygus orbicularis’ maintain their characters
and thickness below the ‘Sables a Scaphites,’ and have also yielded
many of the same fossils.

The Craie glauconiense, however, partakes in the prevalent
change, losing its calcareous ingredient, and passing into beds of
fine micaceous sand and ferruginous clay, so different in appearance
from Craie glauconieuse that they might have been referred to a
lower horizon, were it not that they contain in places some of the
characteristic fossils of the zone of Ammonites Mantelli, such as
Ammonites Vibrayeanus, A. falcatus, and A. rotomagensis.

As regards the ‘Glauconie 4 Ostrea vesiculosa’ M. Guillier
remarks :—‘In the west of the department there exist beds of
glauconitic material which seem to be the prolongation of these, but,
as they do not contain fossils and are intimately united with the
overlying beds (argile glauconieuse 4 minerai de fer), we have not
separated them.’ Clearly some further investigation of these beds is
required, and we may hope that the survey of the Sarthe on which :
M. Bizet is now engaged will enable him to determine whether the
O. vesiculosa-beds die out entirely, as we should think most probable,
or whether some representative of them really does occur at the
base of the ferruginous clays.

136 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

From the above description it will be seen that the Cenomanian,.
which in the Calvados and in the north of the Orne consists chiefly of
calcareous and micaceous material, is, near Le Mans, wholly repre-
sented by sands with a base of glauconitic clay. M. Guillier does:
not give the complete sequence at Le Mans in one view, but from:
his account it appears to be as follows :—

Feet.
Sables supérieurs a Rhynchonella compressa .............0.00- about 54
Sables et grés ferrugineux a Scaphites equalis 930
Sables et grés a T’rigonies et Perna lanceolata {********" %
Arcile glauconieuse aminerai de ter o.oo... .-apesec nese s-nse- ene 30 to 50
About .2-.2: 330

All these sands, and part, at any rate, of the basal glauconitic
clay, are without doubt the correlatives of the Cenomanian of Cape
La Heéve, as defined by M. Lennier and ourselves. In other words,.
we do not believe that the ‘Gres du Maine,’ as the central group of
sands has been called, includes any representative of our Upper
Greensand, but that it is merely a littoral deposit of the age of our
Lower Chalk. The palzontological questions raised by this con-
clusion remain to be discussed. Our view of the correlation of the
Cenomanian deposits in the West of France and South of England.
is shown in the Table facing p. 172.

V. Tue MInvTE SreuctuReE OF SOME OF THE BEDs IN ENGLAND
AND FRANCE.

The Cenomanian of Devon.

In hand-specimens the gritty limestone which forms the base of
our zone of Ammonites Mantelli in the Devon series, and which is.
known as Bed 10 of Mr. Meyer, presents on its fractured surface a
coarse, granular texture, sparkling with broken quartz-grains, often
as large as apea, and with calcitic crystals; not unfrequently, how-
ever, it is smoother and more compact, and sometimes seems to:
include pebbles of a finer material. When thin sections are
examined under the microscope the rough, coarse-grained specimens:
are seen to be a sand composed of shelly fragments, minute portions.
of what seems to have been a previously consolidated deposit,
foraminifera, and a few sponge-spicules. Large quartz-grains,.
some angular and some well rounded, are plentifully scattered
through this sand, with here and there a grain of glauconite. The
whole is cemented together by a clear crystalline calcite into a
gritty limestone. In other parts of the rock the matrix seems to
‘ have been formerly a fine calcareous paste, which is now in the
condition of a finely granular crystalline limestone.

As a whole, the structure of the shelly fragments is obliterated in
the general crystallization, and their derivation is uncertain : their
general outline does not suggest the prisms of Jnoceramus-shells,

Wel. 52.3 A DELIMITATION OF THE CENOMANIAN. 137

but rather pieces of Pecten, fragments of the tests or spines of
echinodermata, polyzoa, and perhaps coral.

Foraminifera are not uncommon, the genera represented being
chiefly Tevtularia, Cristellaria, and Rotalia; Globigerina is rare
or absent, and calcareous ‘spheres’ do not occur at all. Although
free sponge-spicules are uncommon, there is much sponge-structure
(? of calcisponges).

Bed 11.

Bed 11 resembles the finer and more shelly portions of Bed 10,
and specimens from Hooken Cliff, Beer Head, and elsewhere present
the same character. Like Bed 10, it consists of calcareous particles
derived from various sources, foraminifera, sponge-spicules, with
many quartz- and glauconite-grains, the latter being more common
than in Bed 10. The whole is cemented together by crystalline
calcite.

Bed 12.

This bed is a dense, hard, crystalline limestone, with smooth
fracture, containing many grains of quartz and glauconite, those of
glauconite being still more abundant than in Beds 10 and 11.

Examination of thin slices proves it to be a true chalk, having a
matrix of fine, amorphous, calcareous matter, now converted into
granular calcite, in which are scattered a few shelly fragments,
foraminifera, and some sponge-spicules. Spheres are common—
the general aspect being that of certain specimens of Chalk Marl or
Grey Chalk. But the rock in other parts contains many coarse
shelly fragments and large glauconitic grains; these areas, though
well defined, are not sharply marked off, and seem to be integral
portions of the rock.

Bed 13. Hooken Cliff.

The structure of Bed 13 seems to vary at different places, but
more examples are necessary to make sure of this point. The type
may be taken as the marked zone of Belemnitella plena at Hooken.
Here the matrix consists of fine amorphous calcareous matter and
minute calcitic crystals. A few coarse fragments occur which can
be identified as shell, and spheres and small-sized foraminifera are
common. ‘The feature of the rock is the abundance of large angular
and rounded quartz-grains, and large grains of glauconite. The
whole is loosely compacted, and forms a friable gritty stone.

The lower part of this bed has a somewhat different aspect. It
is a compact glauconitic chalk, full of quartz-grains and coarse
shelly fragments; variety of structure in the latter indicates deri-
vation from various sources. A specimen supposed to be 13, from
between Lyme Regis and Pinhay, shows a structure which ap-
proximates to that of Bed 14—the glauconitic base of the Middle
Chalk

138 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

Base of the Middle Chalk.

Specimens from Lyme Regis, Bindon, Beer Head, and Branscombe
show that the usual change takes place, and that the compact
glauconitic chalk at this horizon consists chiefly of spheres thickly
packed in the fine calcareous material of the matrix. Globigerine
are among the most common foraminifera, but are not very abun-
dant, and the shelly fragments consist chiefly of Jnoceramus-prisms.
Large quartz- and glauconite-grains still characterize the deposit,
but they pass away in about 3 feet, and the rock has then the
usual characters of Middle Chalk.

The Upper Greensand (or Gaize).
Cape La Héve.

For the purposes of this paper it is only necessary to describe
the minute structure of the upper part of the Upper Greensand
(the Gaize) in order to show that the material of which this
division is composed differs considerably from that of the overlying
Cenomanian.

Viewed under the microscope in thin sections, the matrix of the
Greensand is seen to consist largely of fine, amorphous, siliceous
matter, probably silicate of alumina, intermingled with which are
minute calcareous particles. There are very few foraminifera, and
not many shell-fragments or sponge-spicules. Globules of colloid
silica are present, but not abundant. The proportion of quartz-
sand is large, but the grains are small and angular; mica-flakes may
be recognized. Rather large grains of glauconite are common, but
not abundant. The rock compares well with a specimen of the
upper part of the Upper Greensand of the Isle of Wight, taken
from Culver Cliff, except that the grains of quartz and glauconite
are distinctly larger.

Isle of Wight.

At the top of the Upper Greensand grains of glauconite become
very abundant, and these and the quartz-grains are coarser, and the
rock more calcareous. Specimens from Beds 2, 4, and 5 (see p. 105)
from Collins Point show distinctly the commencement of a transition
from Upper Greensand conditions to those of Chalk Marl.

The Cenomanian of France.
The Chloritic Marl of Cape La Héve.

The bed containing many black phosphates, which we take as
the equivalent of the Chloritic Marl, will not compare in its minute
structure with that of the Isle of Wight. It is a less calcareous
deposit, it contains more fine inorganic material, and the grains of
quartz and glauconite are more numerous and larger; indeed, as
already mentioned on p. 121, some of the former are small pebbles.
There is a little colloid silica, but few sponge-spicules, shell-frag-
ments, or foraminifera.

Nol. 52: | A DELIMITATION OF THE CENOMANIAN. 139

The rock, as a whole, when viewed in thin section under the
microscope, ‘resembles more nearly the Cambridge Greensand than
any of our specimens of Chloritic Marl.

Bed 6.

Seen from a short distance, the yellowish-white chalk into which
the Chloritic Marl quickly passes, and which forms the major part
of the Cenomanian in the cliffs between St. Jouin and Cape La Heéve,
looks like the rock we are accustomed to see on this side of the
Channel; but a striking difference is seen in the lines of massive
cherts which occur at irregular intervals from near the base to the
summit.

A more critical examination shows that the lower part of the
Cenomanian, all that included in Bed 6, possesses peculiarities not
found in the Chalk of England. These are comparative lightness in
the hand, a certain amount of gritty mealiness to the touch; and
it is everywhere speckled by glauconitic grains, and a few minute
mica-flakes sparkle on its fracture.

These peculiarities extend through Bed 6, and then there is a
gradual passage to that white pulverulent limestone with which we
are familiar.

When a thin section of Bed 6 is examined under the microscope,
the matrix is found to be made up partly of fine, amorphous, cal- ©
careous matter, mixed probably with a small proportion of fine
inorganic material, and partly of calcite in the condition of definite
though minute crystals. The rock is full of shelly fragments, the
derivation of the larger part of which is uncertain, but prisms of
Inoceramus-shell are clearly less numerous than in shelly English
chalk ; such fragments as show structure are more frequently those
of Pecten or portions of the spines or tests of echinodermata.

Foraminifera are present, but are not very numerous, the forms
most in evidence being Textularia, Cristellaria, and Rotalia ; G'lobi-
gerina is rare, and spheres do not occur at all.

Intermingling with these calcareous elements are many sponge-
spicules whose silica is invariably in the colloid state. These are
sometimes closely packed, sometimes widely separate, but they are
always present in greater number than in any English Chalk,
except, perhaps, selected specimens of siliceous Chalk Marl.

Permeating the whole mass in single globules or ag sregations of
globules, is a “large amount of colloid silica.

Glauconitic grains of large size, compared with those of our Lower
Chalk, are seen in all specimens, sometimes in great abundance, and
glauconite may also be seen infilling the spicular canals and the
chambers of foraminifera.

Quartz-grains are common, but the quantity varies much in
different specimens; they are everywhere more numerous and larger
than in the English Chalk Marl, and some are angular.

This general description will apply to the whole of Bed 6 between
St. Jouin and Cape La Héve. Sometimes the fine material prepon-
derates, there are fewer quartz- and glauconite-grains, and the

140 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,.

chalk has a correspondingly denser texture. In other specimens,
especially where sponge-spicules are numerous and there is much
colloid silica, the fine and denser material seems to be in isolated
grains or patches, and the rock has a granular aspect on its fractured
surface. These grains seem to consist of fine calcareous material
cemented by colloid silica or amorphous siliceous material.

The structure of the rock, then, somewhat resembles that seen
in Beds 10 and 11 of the Devon Cenomanian, namely, separated.
calcareous fragments cemented together. The similarity is even
carried further by the absence of Gilobigerinw and ‘spheres,’ and
by the comparative rarity of Inoceramus- prisms, while shelly
particles, whose derivation is uncertain, abound in both deposits.

The differences between Bed 6 of La Héve and Bed 11 of the
Devon series are the abundance of sponge-spicules and colloid silica
in the former, and the greatly superior size of the glauconite- and
quartz-grains in the latter. Moreover, the rock of Bed 6 never
becomes a crystalline limestone, and is usually in a condition which
admits of its particles becoming readily detached.

Hard beds and semi-crystalline lumps do occur, especially at
St. Jouin, but nothing in the specimens we brought home, either
from this locality or La Héve, completely parallels the granular
structure of Beds 10 and 11 of Devon; in one from Vimoutiers,
_ however, this structure is almost exactly reduplicated.

The presence of so much quartz and glauconite, the abundance of
sponge-spicules, and the absence of Globigerine and spheres seem to
show that this part of the Cenomanian was laid down in shallower
water and nearer a coast-line than the English Chalk Marl.

Beds 7 and 8.

From near the base of Bed 7 the rock passes to a deposit which:
we may compare with our Grey Chalk. It consists of the usual
amorphous calcareous matter, in which are scattered small shell-
fragments, a few calcareous spheres and foraminifera. Globigerine
continue rare. Sponge-spicules occur, but are less numerous, and
there is little or no colloid silica. The Chalk at this horizon differs.
from its English equivalent in the presence of sponge-spicules, and
in the occurrence of grains of glauconite and quartz. It is true
that minute particies of both these minerals are to be seen far up-
in the Grey Chalk in the neighbourhood of Warminster and Devizes,
but neither are found commonly in the Chalk of the Isle of Wight,
which approaches most closely (so far as distance is concerned) to:
that of Cape La Heéve.

Specimens taken from the base of the Turonian at Brunval show
that the Chalk at this horizon is full of ‘spheres’ and Jnoceramus-
prisms, and is similar to that at the base of our Middle Chalk.

Vol. 52. | A DELIMITATION OF THE CENOMANIAN. 141

Calvados and Orne.

South of the Seine we confined our examination of the litho-
logical characters of the Cenomanian to Beds 5 and 6. In this
direction we saw nothing corresponding to the ‘ Gaize,’ and where
the top of Bed 4 was exposed the material was a soft and exceed-
ingly glauconitic sand. A specimen from Bed 5, near Honfleur,
compares with the base of Bed 6 at La Héve rather than the Chloritic
Marl (Bed 5), except that it contains so many large glauconitic
grains, quartz-grains being in rather small quantity. Neither do
sponge-spicules or colloid silica occur commonly in this specimen.
The cementing-material of the hard lumps found in this bed is
crystalline calcite.

Southward of Honfleur we find a steady increase in the amount
of quartz-sand and organic silica in Beds 5 and 6.

Thus, at Blangy, the matrix of a specimen from 10 or 12 feet
from the base of the Cenomanian consists—judging by the eye—
of at least 50 °/, of globular colloid silica, and the amount of sand-
grains (quartz) mingled with this is greater than in any specimen from
La Héve. Mica-flakes can also be recognized, and among the sand
are grains other than those of quartz. Glauconite is present as usual,
there are a few shell-fragments and much amorphous calcareous
matter ; sponge-spicules are common.

Specimens from Orbiquet taken at a higher horizon, one about
20 feet and another from about 45 feet above the base of Bed 6, show
a similar increase in the amount of colloid silica and terrigenous
material, the relative proportion of this decreasing upwards.

We regret that we omitted to secure a series of specimens from
Bed 6 at Vimoutiers. Our knowledge of the minute structure of
the Chalk here is obtained from that adhering to our fossil speci-
mens, their height from the base of the bed being uncertain. . Such
specimens show that the conditions noted at Orbiquet continue to
this point without much alteration.

One specimen showing a structure somewhat similar to that of
Bed 11 has already been alluded to.

Still farther south we find that the base of Bed 6 has completely
changed from a calcareous to a siliceous rock, comparable with the
Malm of our Upper Greensand.

At Gacé, in the hard bed at the base of the Cenomanian, the
equivalent of Bed 5 at Cape La Héve, the cementing-material is not
calcite but silica, derived probably from the abundant spicules in
the deposit, and much of this silica has passed from the colloid to
the chalcedonic condition. The so-called ‘Craie’ which overlies
the basement-bed is so completely siliceous that the reaction in
acid is of the slightest, while at still higher horizons the deposit is
not a chalk at all, but a sandy, micaceous, glauconitic, calcareous
silt, with many sponge-spicules, amongst which the reniform
spicules of Geodia* are common.

1 Identified by Dr. G. J. Hinde.

142 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

Hence it is not surprising that the fauna of the French Ceno-
manian should differ considerably from the fauna of the Lower Chalk,
although we firmly believe that they existed contemporaneously.

VI. Criticat RemMARKs ON SOME OF THE Fosstts.°

The preparation of the following lists of fossils has involved a
considerable amount of critical work, in which we have been greatly
assisted by Mr. C. J. A. Meyer, F.G.S., and Dr. G. J. Hinde, F.G.S.
Mr. Meyer has collected and studied the fossils of the Devon cliffs
for the last twenty-five years, and has bestowed much time and
care upon the identification of the various species of echinoidea and
mollusca. The differences between the lists of these classes of
animals now given and those in his paper on the Beer Head sections
(Quart. Journ. Geol. Soc. vol. xxx. 1874) are chiefly due to his own
researches, the results of which he has generously communicated
tous. They have resulted in some corrections and in many fresh
identifications among the fossils in his unequalled collection. Some
of the specimens in this collection have already been figured by
Lycett and Davidson in the publications of the Paleontographical
Society, and many others are awaiting the preparation of other
special monographs. |

To Dr. Hinde we are indebted for examining, and naming so far
as possible, all the sponges, hydrozoa, and polyzoa collected by
ourselves in Devon and in France.

In order to explain the appearance of certain names in the lists
of fossils, we have thought it desirable to set forth the results of
these combined investigations and to make some critical remarks on
those species which are interesting, either from their being unknown
in England or from our having found a difficulty in identifying
them. In several cases also we have been able to determine the
identity of English and French species which had previously borne
different names, aud we think that such rapprochements will be
welcomed on both sides of the Channel.

Sponges.

Stavronema Carrert, Sollas, Ann. Mag. Nat. Hist. ser. 4, vol. xix.
(1877) pls. i.-v.

This fossil was first found by one of us in the so-called ‘ Upper
Greensand’ above the Gault at Folkestone in 1876, and was recog-
nized by Prof. Sollas as a new and peculiar form. In describing it,
however, he stated that it occurred in Gault and Upper Greensand,
having understood that the original specimens came from the
Folkestone Gault, and possessing a specimen from the Isle of Wight
which he believed to have come from the Upper Greensand.

We think that the latter must have come from the Chloritic Marl
of the Isle of Wight, in which the fossil is common, while we have
mever seen one from the Upper Greensand. We agree with

? Mr. Jukes-Browne is responsible for this section of the paper.

Vol, 525] A DELIMITATION OF THE CENOMANIAN. 143

Mr. F. G. H. Price in regarding the glauconitic sand above the
Gault at Folkestone as Chloritic Marl, not Upper Greensand.
We have also found St. Carteri in the Chloritic Marl with phosphatic
nodules near Devizes and Warminster, and Dr. Hinde informs us
that it occurs at the same horizon at Eastbourne and Selborne.
It is clearly, therefore, a fossil especially characteristic of this
horizon, though it may possibly range a few feet up into the Chalk
Marl.

We are also informed by Dr. Hinde that there are specimens in
the British Museum from La Heéve, and we are now able to say that
it is common there in what we regard as the equivalent of the
Chloritic Marl, namely the basal bed of the Cenomanian, and in the
bottom of the overlying bed, but at no higher horizon.

Echinodermata.
GoNIOPHORTS, Sp.

A small specimen from the Chloritic Marl, which has all the
characters of this genus, but differs from Gt‘. lunulatus in several
respects. The apical disc, instead of being in low relief with a
large aperture or periprocte, has its edges raised into rough tuber-
cular ridges, which, with the similarly raised edges of the periprocte
and a set of transverse bars or carine, make a curious pentangular
pattern in five compartments surrounding the periprocte. These
ridges are not plain and straight, as in G. dunulatus, but curved, so
that the outline of the pentagon is irregular.

The test is less elevated than in G. lunulatus ; there are only four
tubercles in a row on the interambulacral areas, and the iower
tubercles are very small, there being only three large ones on each
area. The ambulacral areas are very prominent, and swell out
towards the mouth.

Whether this is more than a very aberrant variety of G'. lunulatus
must depend on the discovery of others with the same characters ;
but it differs so much from the types figured by Cotteau and Wright
that we felt the desirability of calling attention to it.

Copiopsis poma, Ag.

This sea-urchin has not previously been found in England, and,
as it is specially characteristic of the Cenomanian of the Sarthe, its
occurrence in Devon is interesting. ‘The determination is due to
Mr. C. J. A. Meyer, in whose cabinet the only known English
specimens are. M. Bizet having kindly sent us two specimens
of the large inflated form of the species, we forwarded these to
Mr. Meyer, who reports that his are quite small in comparison.
Probably they belong to the variety C. piswm of Desor.

HEMIASTER BUFO, Desor, in d’Orb. ‘ Pal. Fr. Terr. Crét.’ vol. vi.
p. 227, pl. 873.

This is a common species in the North-west of France. It is

especially abundant at Blangy, Vimoutiers, and Villers-sur-Mer, but

144 MESSRS. A, J. JUKES-BROWNE AND W. HILL: [May 138096,

no specimen came to hand from Cape La Heéve, though d’Orbigny
quotes it from there. It is a well-marked species, much more
elevated than H. minimus, the anal area being very high and rising
almost vertically from the base.

We have not seen anything like this species in England, and
Mr. Meyer informs us that the Spatangus bufo of his Devon list in
1874 was a mistake, a better specimen having enabled him to
identify it as Hemiaster Morrisii. Mr. Sharman, to whom we sent.
specimens, compared them with all the Cretaceous Hemiasters in the
Jermyn Street Museum, and did not find any resembling them.

HotastER sUBORBICULARIS, Brongn., figured by d’Orbigny, ‘ Pal. Fr.
Terr. Crét.’ vol. vi. p. 93, pls. 814 and 815. Hol. suborbicularis,
Wright, ‘ Brit. Cret. Echin.’ Pal. Soc. Monogr. p. 314, pl. Ixxiv.
fig. 1

We do not think that the figures above referred to represent the
same species. D’Orbigny’s figure is that of a rather large cordiform
urchin, much resembling Cardiaster fossartus. He describes it as
specially characterized by the bulging out of the under surface in
the hinder part, so that its greatest height is in this posterior
region. Moreover it has a depressed anal area, and the vent is
small and placed in the upper part of this area. The anteal sulcus
is rather deep. .

Dr. Wright’s figure does not show these characters ; there is no
such marked anal area; the vent is large and not very high up.
There is no such prominent basal protuberance. The test is very
different in shape, and is very much smaller. He himself says that
‘the English specimens are small and resemble the urchin described
as Holaster cenomanensis, d’Orb., which, however, is only a small
variety of Hol. suborbicularis.’ He also states that it occurs plen-
tifully in the Chalk Marl and in its glauconitic basement-bed.

This last statement is incomprehensi! le to us, as we have col-
lected largely from these beds, but have seen very few specimens -
that will compare with Wright’s figure of Holaster suborbicularis,
and none like d’Orbigny’s figure. Moreover, in Dr. Barrois’s well-
known ‘ Researches in the Cretaceous Formation of England’ we
find only one mention of Holaster suborbicularis(?), and this is
from the Upper Greensand.

Mr. Meyer informs us that he has some specimens from Bed 11
in Devon which agree with Wright’s figure and a few which come
near to that of d’Orbigny. We have therefore admitted both forms
into our list.

HotastTER, sp.

One of the commonest echinoderms in the zone of Ammonites Man-
telli on the Devon coast is a form which differs from any yet described.
A single specimen might be taken fora small elevated and oval variety
of Holaster subg globosus’ but, as that species occurs in the same beds
and exhibits individuals of ‘all ages, this form is either a different

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 145

species or a well-marked and unusual variety of that species. It
is generally rather over an inch long and rather less than an inch
broad, and about +2 inch high. It is inflated below, and the vent
is placed high. The anteal sulcus is bounded on each side by a
ridge, which swells out near the top and gives a peaky character
to this part of the test.

Mr. Sharman informs us that it comes nearest to a specimen in
the Museum at Jermyn Street from the Middle Chalk of Dover, to
which Prof. Forbes attached the MS. name of Cardiaster Cockburni.

Pyevurvs tampas, De la Beche, Wright, ‘ Cretaceous Echinodermata,’
p- 258, pl. lviii. fig. 1.

The original specimen of this sea-urchin was found by Sir H. De
la Beche near Lyme Regis in what he took to be Upper Greensand ;
‘but as it has never been found again in the Upper Greensand of
Devon, and as Mr. Meyer has obtained a specimen from his Bed 10 at
Dunscombe, it probably came from the same horizon near Lyme Regis.
Many of the blocks on the shore west of Lyme consist partly of the
topmost bed of the Greensand and partly of the quartziferous grits
{Beds 10, 11, 12), and De la Beche might well have regarded the
whole mass as Greensand, for what looks like the base of the Chalk
succeeds No. 12 (see p. 111).

This species is occasionally found in the Cenomanian of Le Mans,
and also occurs at Fouras in the Charente Inférieure; it is therefore
a conspicuous link between the Cenomanian of Devon and Western
France.

Sarenta Crarxi, Forbes, in Wright, ‘ Cretaceous Echinodermata,’
p77, piss xxxvill, xxxix., & xlii-

A large Salenia occurs in the lower part of the Devon Ceno-
manian Bed 11, and again in the highest bed (13). It comes
nearer to S. Clarku of the Lower Chalk of Dover than to any other
figured species, though it does not quite agree with Dr. Wright’s
type. A large specimen measuring more than an inch in diameter
has been deposited in the Museum at Jermyn Street.

SALENIA PETALIFERA, Ag., var.

Some of the specimens referred to this species also differ in some
respects from the type, and somewhat resemble S. scutigera, Gray.
The zone of small tubercles on the interambulacral areas is very
narrow and sinuous, and the apical plate exhibits some characters
which, if constant, would differentiate it from S. petalifera.

Polyzoa.
CaRIOCAVA RAMULOSA, Mich., sp., ‘ Icon. Zoophyt.,’ and d’Orbigny,
‘ Pal. Fr. Terr. Crét.’ vol. v. p. 1017, pl. 788. figs. 11 and 12.

This is a large coral-like organism, branching dichotomously,
‘often 4 or 5 inches in length, and consisting of a number of con-

146 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

tiguous angular tubes which radiate outward and upward from a
central axis. It is a very abundant fossil in the basal part of the
zone of Ammonites Mantelli in Devon, especially at Dunscombe,.
Weston, and at Beer Head.

Specimens having been sent to Dr. G. J. Hinde, he reported that
they strongly resembled the Chatetes ramulosus of Michelin found in
the Cenomanian of the Sarthe. Subsequently M. Bizet, of Belléme,.
sent us a specimen found at Condrécieux (Sarthe), which appeared
to be the same fossil. Dr. Hinde informs us that d’Orbigny placed.
Michelin’s species as a polyzoan under the name of Ceriocava ramu-
losa; but he thinks that when the specimens are more carefully
examined it will be found generically distinct from Ceriopora or
Cervocava.

In Morris’s ‘ Catalogue’ (2nd ed. 1854, p. 120) it is placed under
Ceriopora and said to occur in the Greensand of Faringdon.

Derrancra (Petacia) Evpesit, Mich.

This is another remarkable fossil, having a wonderful resemblance
to a small expanded cup-coral; but it was recognized by Dr. Hinde
as the polyzoan above named, which Michelin describes as common
in the ‘Craie chloritée’ of Vaches Noires and in the ‘ Grés vert’ of
Le Mans. Only one specimen has been found in the lowest layer
(Bed 10 of Meyer) of the Mantelli-zone near Branscombe.

MicropPora.

The two species of Micropora entered in the list of Devon
fossils, and numbered 4 and 5 respectively, are recognized by
Dr. Hinde as occurring also among the specimens collected from
the Chloritic Marl near Cape La Heve, although he is at present
unable to identify them as described species.

Brachiopoda.

RHYNCHONELLA DIMIDIATA, Sow., and Ra. azara, Brong.

In Guillier’s ‘ Géologie de la Sarthe’ (1880), and in some of
M. Bizet’s papers on the geology of the Orne and Sarthe, we find
Rhynchonella alata, Lam., stated to be a common Cenomanian shell ;
but Davidson (‘Brit. Cret. Brach.’ vol. i. p. 82) mentions that
MM. d@’Orbigny and Deshayes agree with him in considering the
Rh. alata of Lamarck as merely a synonym of Rh. vespertilio of
Brocchi.

Later, in his ‘Supplement,’ when discussing Rh. dimidiata,
Davidson states that the names alata and gallina were given by
Brongniart to symmetrical forms of this shell, and dimidiata by
Sowerby to the unsymmetrical form. It is therefore the Rh. alata
of Brongniart, and not of Lamarck, which is the common Ceno-

manian shell.
Both varieties are very abundant in the Cenomanian of Devon,

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 147

and we have compared them with a number from different localities
in France. There is no doubt about the identity of the English
and French forms, and it is desirable that Sowerby’s name should
be recognized in France as it isin England and Germany. Rh. con-
vexa, Sow., also occurs in the French Cenomanian.

RuyYNCHONELLA WreEstII, Quenst. (1871), and Davidson (1874), in
Supplement to ‘ Brit. Foss. Brach.’ p. 66, pl. viii. fig. 31.

The shells referred by Davidson to this species are very common
in Bed 13, the sandy chalk which overlies the zone of Ammonites
Manielli in Devon. Itis a much more variable species than Davidson
seems to have supposed, for he describes it as having ‘ about 30 or 32
rounded ribs,’ and adds that it approaches most nearly to Rh. Gra-
siana, * of which it may perhaps be a large variety.’

Having collected many specimens from this bed wherever it is
found, we cannot agree with Davidson. The shell seems to us
much more closely allied to £A. Cuviert, from which it can only be
distinguished by having, as a rule, fewer and larger ribs. The
average number seems to be 24 or 26, but there are forms which
have as few as 13 and others which have as many as 30; the
former resemble Rh. Mantelliana, except that the ribs are not
angular, and the latter come so near to the broader varieties of
Rh. Cuviert that, when placed beside them, they are indistin-
guishable.

Although both the names Cuviert and Manielliana have been
admitted into our list, we believe the specimens so named are
extreme varieties of one species, which may be called RA. Wrestir,
and may be regarded as the ancestor of Ah. Cuviert and Rh. reed-
ensis, Eth., which occurs still higher in the zone of Holaster planus.

TEREBRATULA TORNACENSIS, d’Arch., Mém. Soc. géol. Fr. ser. 2.
vol. ii. p. 316, pl. xviii. fig. 3, and varieties figs. 4-5.

This species was founded on specimens from the Tourtia of
Tournay, and as this deposit is now known to be the littoral facies
of the Cenomanian in Hainaut, and of later date than the zone of
Ammonites inflatus, the occurrence of Tourtia forms in the Ceno-
manian of Devon and Sarthe is not surprising.

When Davidson first described the Faringdon fossils in 1852
he identified certain forms as 7’. tornacensis, var. Roemeri, d’Arch.,
though he was evidently for some time in great doubt about them
(see ‘ Brit. Cret. Brach.’ vol. i. p. 62). At that time he imagined
that the Faringdon Sand was of Upper Greensand age, and, as the
Tourtia was then supposed to be a sort of combined Lower and
Upper Greensand, he saw no reason why a Tourtia species should
not occur at Faringdon.

It seems, indeed, to be a fact that some of the forms of 7’. depressa
and 7’, tornacensis occurring in the Tourtia are practically indistin-
guishable from varieties of 7’. depressa and T’. sella which occur in
the Lower Greensand of England; but the typical form of 7’. torna-

Q.J.G.S8. No. 206. M

148 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

censis is certainly different from the typical 7’. sella, so that it is
only the smaller varieties and the distorted forms which resemble
one another.

Subsequently (‘Supplement, 1874, pp. 35, 36), and after
correspondence with Mr. Meyer, Davidson was led to alter his
opinion so far as to admit that the forms previously attributed to
T'. tornacensis were really only varieties of 7’. sella.

We agree with Mr. Meyer 1 in regarding 7’. tornacensis as essen-
tially a Cenomanian species, and we are able to state that it occurs
in the typical Cenomanian of Le Mans, where it seems to have been
confused with 7’. biplicata. M. Bizet has sent us three specimens
under the latter name which in the opinion of Mr. Me er and our-
selves are typical 7’. tornacensis, differing from biplicata by the very
characters pointed out by d’Archiac.

In Devon a few specimens have been found by Mr. Mejer in the
beds described by him as 11 and 12 at Beer Head.

Whether the real 7’. biplicata occurs near Le Mans as well as
T. tornacensis we have no means of knowing, but it does not seem to
occur in Devon and it does not occur in the Tourtia of Tournay; it
is common in the Chloritic Marl of the Isle of Wight, and occurs in
that of Havre, as well as at Orbiquet (Calvados) and Vimoutiers
(Orne).

‘TEREBRATULA ARENOSA, d’Arch., op. cit. p. 324, pl. xxi. figs. 1-3.

This is another Tourtia form recognized by Mr. Meyer in the
Devon Cenomanian. It is a small globose species, the surface of
which bears scattered granules or small tubercules with depressed
summits, so that they resemble minute craters. It might easily be
passed over as a globose form of Megerlia lima.

TEREBRATULA VERNEUILI, d’Arch., op. cit. p. 326, pl. xx. fig. 4.

This shell is not likely to be mistaken for any other species, as it
bears a very remarkable ornamentation on both valves. They
display a series of short, strong ridges, arranged in concentric rows
and separated by oval indentations or hollows, so that the shell seems
covered by a raised crochet-work pattern. The hollows are deepest
at the top, and those of one row lie below the ridges of the row
above. Inthe adult shell these ornamental ridges die away towards
the edge of the shell.

Mr. Me\er has found this form in the same bed at Beer Head
as that which contains 7’. tornacensis and T’. arenosa.

TEREBRATULA CAPILLATA, d’Arch., and T. sevamosa, Mantell.

We think that there is a much closer connexion between these two
species than has hitherto been supposed. In discussing the rela-
tions of 7’. capillata Davidson only distinguishes it from 7’. depressa,
to which d’Orbigny had imagined that it had some resemblance ;
and in describing 7’. syuamosa he does not mention 7, capillata. Yet

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 149

it is only necessary to look at plate v. of his Monograph, where
both shells are figured, to see how nearly they approach one another
through the least lamellose variety of 7’. syuamosa (fig. 11).

Davidson says that 7’. syuamosa is very common in the ‘Craie
-chloritée of Rouen’; it may be so, but in the middle of the ‘ Craie
glauconieuse of St. Jouin’ we find a form which is quite destitute
of squamose ridges, and is ornamented with nearly straight but,
slightly undulating, capilliform striez. Except that it is of small
size, it agrees more closely with d’Archiac’s figures of 7’. capillata
(Mém. Soc. géol. Fr. ser. 2, vol. ii.) than with the 7’. capillata of the
Red Chalk figured by Davidson.

In this connexion we would recall the fact that 7. capillata
‘has been found by one of us in the Totternhoe Stone or ‘Grey Bed’
of Lincolnshire, and consequently well up in the Lower Chalk (see
‘Quart. Journ. Geol. Soc. vol. xliv. p. 349). It has therefore a wider
distribution in beds of Cenomanian age than in those of earlier
-epochs, and we are inclined to think that the Lower Greensand form
figured by Davidson may have to be separated from it.

Lamellibranchiata.

-OsTREA CANALICULATA, Sow. =O. LaTERALIs, Nilss.

This is the Chama canaliculata of the ‘ Min. Conch.’ vol. i. pl. 26.
fig. 1 (1812), not the Ostrea canaliculata of a later volume (pl. 135.
iz. |).

ott Chama canaliculata of Sowerby is the Ostrea lateralis of
Nilsson (1827), as pointed out by d’Orbigny ; and, having compared
many French and English specimens, we agree in regarding them
as the same shell, but Sowerby’s name has the priority.

The shell which Sowerby called Ostrea canaliculata cannot bear
that name, and, as it seems to be identical with the O. lunata of
Nilsson, it should be so designated.

O. canaliculata (Sow., sp.) is a characteristic Cenomanian shell,
and O. lunata belongs to the highest White Chalk of Trimingham
and Mundesley.

PECTEN INTERSTRIATUS, Leym.

This name has frequently appeared in lists of Cretaceous fossils,
and has been applied indiscriminately to Lower and Upper Creta-
ceous species. Leymerie, in 1842, gave the name to an Aptien
species which is figured by d’Orbigny under that name in the ‘Pal. Fr.
Terr. Crét.’ pl. 433. figs. 1-5, but in his *‘ Prodrome’ (vol. ii. p. 169)
he changed the name to aptiensis,because he found that interstriatus
had been used for another species by Minster in 1841. The latter
name, therefore, should not be used for any of the Cretaceous Pectens.
The Lower Greensand species (P. aptiensis) has its own distinctive
characters and does not range into Gault or Upper Greensand
though it doubtless was the ancestor of the later interstriate Pectens.

M2

150 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

Prcren Durempret, d’Orb., and Pecten GALLIENNEI, d’Orb.

These are two of the species which have gone by the name of
interstriatus in England. P. Dutemplei is described by d’Orbigny
as having plain narrow ribs between the larger ornamented ribs,
and as having its ears marked only by vertical lines of growth.
P. Galliennet he describes as wanting the intermediate ribs and as
having several strong radiating ribs on the buccal ear. The first
is supposed to be confined to the Gault (Albien) and the second to
the Cenomanian. We do not feel certain that the latter is more
than a variety of the former, or that they are confined to separate
stages. M. Bizet has sent us a specimen from the Cénomanien of
Condrécieux which he calls P. Galliennei, though it has the inter-
mediate ribs of Dutemple. Specimens from La Héve, Warminster,
and the Cenomanian of Devon do, however, agree better with Gal-
henner, and we have therefore so named them.

Pecren Passyi, d’Arch., Mém. Soc. géol. Fr. ser. 2, vol. ii. p. 309,.
pl. xv. fig. 9.

This is a fossil from the Tourtia of Tournay, and has a consider-
able resemblance to P. Galliennei, d’Orb., but is described as having
perfectly straight, regular, and plain ribs, without any scales or
nodulations. ‘The interspaces are striated in the usual manner,.
Mr. C. J. A. Meyer has specimens which possess these characters
from his Bed 11, Dunscombe Cliff.

PECTEN SUBINTERSTRIATUS, d’Arch., Mém. Soc. géol. Fr. ser. 2, vol. ii.
pl. xv. fig. 10.

Specimens which agree with the figure and description of
d’Archiac occur in the Cenomanian of Devon. It is distinguished
from the other interstriate species by its more numerous ribs, which
are in low relief and are crossed by fine concentric lines of growth,
each line where it crosses a rib developing a small short scale.
These scales are much more numerous and much less prominent
than those of P. Galliennei ; they are most strongly marked on the
anterior portion of the shell, and are mere slight ridges on the central
ribs. The ears are plain or marked only by vertical lines of growth;
the anterior ear is much larger than the posterior.

D’Archiac figures only a right valve, and, as Leymerie only figured
a left valve of his P. interstriatus, d’Archiac cautiously remarks that
his specimen may be only a right valve of that species. We have,
however, a left valve which is clearly that of subinterstriatus, the
only difference being that the ribs are rather fewer and placed at
less regular intervals.

The P. subintersiriatus figured in Dixon’s ‘Geology of Sussex,’
pl. xxviii. fig. 19, is wrongly so named, but is doubtless the P. cre-
tosus of Detrance (non Goldf.), as stated on p. 336 of that work, this
_P. cretosus being probably the same as P. nitzdus, Mantell.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 151

Prcren ELONGATUS, Lam.

There is much doubt about this species, because the figures given
by d’Orbigny and Goldfuss are not alike, and because d’Orbigny’s
description does not agree with his figure. We take d’Orbigny’s
description as the best guide (‘ Pal. Fr.’ p. 607), and from this we
learn that it has 30 to 40 unequal ribs, sometimes alternating
large and small ribs, sometimes grouped in threes (one large and
two small ones), each having prominent lamellose scales at intervals.
His figure, however, does not express these characters at all clearly.
We have found specimens at La Héve which agree with his descrip-
tion exactly and are also identical with specimens from the Lower
Chalk of England which we have been accustomed to regard as
P, elongatus. In all of them there is a marked tendency for the
ribs to be arranged in threes, a large one in the centre with a small
one on each side.

Dr. Barrois states! that this species is identical with the form
figured under the name of P. eretosus by Goldfuss (‘ Petr. Germ.’
pl. xciv. fig. 2), and the figure certainly agrees with d’Orbigny’s
description. P. elongatus of Goldfuss is a Tertiary species.

It differs from P. Marrotianus in not having two minor ribs
between each of the groups of three, in being much less regular, and
in having much more prominent scales. We have not seen this
species from the Cenomanian of Devon, though it ought to occur
there.

Prcren cf. Puzostanus, Math. in d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. iii,
p- 610, pl. 437. figs. 1-4.

This is another case in which d’Orbigny’s figure and description
do not entirely agree. The figure shows perfectly plain ribs of
unequal breadth, but set close together, interrupted only by con-
centric lines of growth; yet d’Orbigny says that the ribs are fur-
nished on the sides with imbricated plates: he adds, however, that
these plates are wanting in the middle of the shell, ‘ but may there
have been abraded.’

We have specimens both from France and from Devon which
much resemble the figure, except that their ribs are rather fewer,
flatter, and more strongly marked, but there is no trace of their
ever having borne imbricating plates; possibly these were very
‘delicate and easily removed. From its occurrence in the typical
Cenomanian country we think that this must be the shell described
by d’Orbigny.

Prcoren susacutus, Lam. in d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. iii.
p- 605, pl. 435. figs. 5-10.

We had found a Pecten in the lowest part of the Devon Cenoma-
nian which seemed to be this species, but its state of preservation

* *Mém. sur le Terr. Crét. des Ardennes,’ Ann. Soc. géol. du Nord, vol. v.
(1878) p. 318.

152 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,.

was not good enough for certain identification. Fortunately,.
however, M. Bizet was so kind as to send us two specimens of
P. subacutus from the Sarthe, and these enabled us to satisfy our-

selves that the Devon species is the same. By the same means also
Mr. Meyer has been able to identify a specimen in his collection.
We have not seen it from any other locality, and it is another of

the links which connect the Devon beds with the Cenomanian of
the Sarthe.

PECTEN, sp.

A species occurs in the Cenomanian of France, and also in the:
highest greensand of Warminster, which we have not been able to
identify. It bears a certain resemblance to P. Raulinianus of the
Gault, and appears under that name in some lists, but the ornamen-
tation is really very different. The shell bears a large number of
narrow ribs, nearly straight, but of unequal size, smaller ribs being
frequently, but not constantly, developed between those of normal.
size. Each rib bears a number of strong, triangular, spinous:
processes, arranged longitudinally, and projecting almost vertically
upwards. Some of the smaller ribs bear similar but more slender
spines, and some are nearly smooth. There are no striz on the
interspaces. The ears are not preserved on the few specimens that
we haveexamined. We arenot sure that it occurs in Devon, though.
some badly-preserved specimens resemble it.

Lima simpiex, d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. ii. p. 545, pl. 418.
figs. 5-7.

In the lower and most fossiliferous part of the Devon zone of Am-
monites Mantellc there are several large, smooth species of Lama, and
having obtained a specimen of Lima simplex from the Cenomanian
of Vimoutiers, we find that one of the Devon species bears a close
resemblance to it. It is large, compressed, and smooth over the
greater part of the shell, but has a few narrow grooves on the
anterior and posterior sides of each valve, which produce a sort of
false ribbing on these portions of the shell.

Lima Hoek, d’Orb. (non Sow.), and Lima Catyrso, d’Orb.

D’Orbigny’s figure of Lima Hoperi has led to some confusion, for’
it is certainly not the Lima Hoperi of Sowerby and Mantell, which
is common in the Upper Chalk (Sénonien) of England, especially in
the Margate Chalk. Assuming d’Orbigny’s figure to be that of an
adult specimen, it is much smaller, more compressed, and orna-
mented all over by shallow pitted grooves; whereas the true
L. Hopert is a large shell, more inflated, and smooth, except over
narrow spaces on the anterior and posterior sides of each valve,.
which have a few faint grooves.

In the Cenomanian of Devon there is a Zima which somewhat.
resembles the shell figured by d’Orbigny as ZL. Hoperi, but it is
more inflated, and has a deeper and more irregular set of pitted.
grooves over the greater part of the shell. This may be the Lima

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 153

Calypso of d’Orbigny, described in his ‘ Prodrome,’ vol. ii. p. 167, as
very near (‘voisine’) to L. Hopert, but with more numerous punctated
grooves, and occurring in the Cenomanian of Rouen.

Corsis RoTunpDaTA, d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. iii, p. 113,
pl. 280.

This is another shell, occurring in the Devon zone of Ammonites
Mantelli, which the acquisition of French specimens has enabled us
to identify. We should mention, however, that Mr. Meyer has
specimens which he had previously determined to be C. rotundata.
It is common in the sandy facies of the Cénomanien at Vimoutiers,
Gacé, and Mortagne, though the shell so often remains in the matrix
that it is difficult to obtain more than casts of it; the same is the
case in Devon, but a comparison of the casts leaves no doubt as to
the identification.

Arca LieERrensis, d’Orb., ‘Pal. Fr. Terr. Crét.’ vol. ili. p. 227, pl. 317.

This is another common shell in the French Cenomanian which
had been detected in the Devon beds by Mr. Meyer. Having
obtained several casts of it from Vimoutiers and elsewhere, we are
also able to state that it is common in the hard rocky basement-bed
of the Lower Chalk at Chard (commonly called ‘ Chloritic Marl’).

TRIGONIA AFFINIS, Sow.

This species was at first regarded by Lycett as only a variety of
Tr. excentrica, Park. (see ‘ Brit. Foss. Trigoniz,’ Pal. Soc. Monogr.
p- 94), but in his Addenda (p. 187) he separates it again, and points
out the characters by which it is distinguished. The only specimens
which he refers to this species are one said to have come from
Blackdown, now in the Jermyn Street Museum, one from Haldon
(Mr. Vicary), and one in Mr. Meyer’s collection, from near Axmouth,
which Mr. Meyer informs me came from his Bed 12, the upper part
of our zone of Ammonites Mantell. It is therefore a rare shell.

TRIGONIA DUNScOMBENSIS, Lycett, ‘ Brit. Foss. Trig.’ Pal. Soc, Monogr.
p- 188, pl. xl. figs. 5, 6.

This species was entered in Mr. Meyer’s list of 1874 as ‘sp.
allied to 7’r. sinuata, Park.,’ and was described as a new species by
Lycett in 1877. Mr. Meyer informs us that it occurs throughout
the zone of Ammonites Mantelli,in his Beds 10,11, and 12, at
Dunscombe, Branscombe, Whitecliff, and Pinhay.

It is allied to 7'r. affinis and T’r. excentrica, but though he dis-
tinguishes it from these, Lycett does not attempt to disentangle the
foreign synonyms, neither does he record 7'r. dunscombensis from any
other localities. Under 7'r. excentrica he gives the 7'r. sinuata, Park.,
in dOrbigny as a synonym, and notes that d’Orbigny records this
Tr. sinuata from the lower beds of his Terrain Turonien (7. e. Céno-
manien) at Le Mans, St. Calais, and Condrécieux in the Sarthe.
We have not been able to obtain specimens of this 7’. sinuata, but

154 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

we think it is very likely to be Tr. dunscombensis, for we now know
that the beds are of exactly the same age.

The true Zr. sinuata of Parkinson is only the young state of
Tr. excentrica, Park., and Lycett states (p. 189) that there is no
certain record of 7'r. excentrica occurring in a higher positicn than
the Blackdown Greensand. Mr. Meyer tells us that he has
Tr. excentrica from his Bed 2 (the horizon of the Cowstones of Lyme
Regis), but that it does not occur in the zone of Ammonites Mantelli.

TRIGONIA DEBILIS, Lycett, ‘ Brit. Foss. Trig.’ p. 189, pl. xl. fig. 8.

This is another species akin to T'r. affinis, but is at present only
known from Bed 10 of Mr. Meyer’s notation at Dunscombe.
Lycett thinks that it is the young of a much larger species, but
states that it is quite distinct from the young of any of the known
‘Greensand ’ species of Trigonie glabre.

TRIGONIA CRENULATA, Lam. in d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. ii.
p- 151, pl. 295.

Mr. Meyer has a specimen of this species from Bed 12, obtained
from a block on the shore of Pinhay Bay, near Lyme Regis. It
is said to be a common fossil in the Cenomanian of Vimoutiers and
Gacé, as well as near Le Mans, but we only succeeded in getting
casts of Trigonie which might belong to it, or to the next.

TRIGONIA CRENULIFERA, Lycett, ‘ Brit. Foss. Trig.’ p. 189, pl. xl.
fies. 1, 7, 9:

This was separated from Tr. crenulata by Lycett, the species
being founded on specimens in Mr. Meyer’s collection. They came
from Beds 10 and 11. ‘The chief distinction consists in the promi-
nent zigzag costelle upon the area and escutcheon,’ and the median
furrow of the area is a ‘ deeply impressed groove’ (op. cit.).

Trigonta MrYeri, Lycett, ‘ Brit. Foss. Trig.’ p. 125, pl. xxiii. fig. 6.

_A shell belonging to the aliformis group; it was referred to
Tr. abrupta, Von Buch, by Mr. Meyer in 1874, but Lycett gave
good reasons for regarding it as a new species, and named it after
its discoverer. It occurs in Beds 11 and 12 at Dunscombe and
Pinhay, and has also been found in the fossiliferous basement-bed
of the Chalk at Chardstock.

Trigonta Vicaryana, Lycett, ‘ Brit. Foss. Trig.” pp. 141 & 208,
with figs. on pls. xxiil., xxv., xxviil., & xl.

Lycett fully discussed this species, which he distinguished from
Tr. Archaciana, dOrb. (an Aptien species). He subsequently
adopted Mr. Meyer’s opinion that T'’r. Archiaciana does not occur in
the Upper Greensand or Chloritic Marl of England, the Haldon
specimens referred to that species belonging in reality to Tr. Vi-
aryana.

Both Meyer and Lycett are inclined to regard the Tr. spinosa of

Vol. 52. | A DELIMITATION OF THE CENOMANIAN. 155

@Orbigny, a common Cenomanian shell, as a synonym of this species.
It is certainly not the true 7’. spinosa of Parkinson, and, having
compared a specimen from the Chloritic Marl of Havre with
d@’Orbigny’s figure of 7’r. spinosa and with examples of Tr. Vicaryana
from Devon, we believe them to be identical. Zr. Vicaryana is
therefore a common shell on both sides of the Channel.

Cephalopoda.

AmMMoNITES comPLANATUS, Mant. See Sharpe, ‘ Chalk Mollusca’
Pal. Soc. Monogr. p. 19, pl. vii. figs. 1-3. =A. Largillertianus,
d’Orb., ‘ Pal. Fr. Terr. Crét.’ pl. xev.

Having found a specimen of this rare shell in a fallen mass of
Bed 11 on Pinhay beach, west of Lyme Regis, it is interesting to
observe that Sharpe identifies it with A. Largilliertianus, which has
been found in the Cenomanian of Rouen, and also in that of the
Sarthe, according to M. Guillier (‘Géologie de la Sarthe,’ 1886).
M. Guillier apparently considers the two forms to be distinct
species, for he enters both of them in his list. The original English
specimen was found in the Chalk Marl of Hamsey, near Lewes.

AMMONITES EVOMPHALUS, Sharpe, ‘Chalk Mollusca,’ p. 31, pl. xiii.
fig. 4,

This is another very rare ammonite, of which only one specimen
was known to Mr. Sharpe, obtained from the base of the Chalk in
Man of War Cove, Dorset. Our specimen was found in the sandy
chalk, Bed 13 of Mr. Meyer, in the cliff below Whitlands coast
guard station, west of Lyme Regis.

Ammonites Goupitianus, d’Orb., ‘ Pal. Fr. Terr. Crét.’ vol. iii. p. 317,
pl. xciv. figs. 1-3; and Sharpe, ‘ Chalk Mollusca,’ p. 38, pl. xvii.
figs. 5 & 6.

This is a sharply-keeled ammonite, with faintly-marked sigmoid
ribs, resembling A. varians in form, but distinguished by its suture.
Mr. Meyer has found one specimen in Bed 13 below Whitlands.
Mr. Sharpe had only seen one obtained from the ‘Grey Chalk’
of Hamsey (? Chalk Marl). It has not been found in the Cénoma-
mien of Western France, but occurs in beds of Turonian age at
Saumur on the Loire.

AMMONITES LATICLAVIUS, Sharpe, ‘ Chalk Moll.’ p. 31, pl. xiv. fig. 1.

This form was only known to Sharpe from the Chloritic Marl of
the Isle of Wight, but it has since been found in the upper part of
the Lower Chalk of Yorkshire (see Quart. Journ. Geol. Soc.
vol. xliv. 1888, p. 351). Dr. Barrois has found it to be not un-
ommon in the zone which he calls by its name in the North-east of
France, and which appears to be equivalent to our Chloritic Marl.
In Devon, Mr. Meyer has found a specimen in Bed 11.

156 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,.

AMMONITEs oBTECTUS, Sharpe, ‘ Chalk Moll.’ p. 20, pl. vii. fig. 4.

This is another peculiar ammonite described by Sharpe from a
single specimen obtained by Mr. Wiest at Chardstock, and is one of
the many species which occur at that locality and on the coast.
The specimen found by Mr. Meyer came from his Bed 11, Duns-
combe, and this and one’ from the ‘Chalk with many Micrasters’
of Dover are, so far as we know, the only others yet discovered.

Ammonites Renzviert, Sharpe, ‘ Chalk Moll.’ p. 44, pl. xx. fig. 2.

This is a rare Lower Chalk fossil found in the Isle of Wight and
near Devizes, and also obtained by Guéranger in the Cenomanian
of Le Mans, so that it is one of the species which links the Devon
beds with the Lower Chalk, on the one hand, and with the typical.
French Cenomanian on the other. Mr. Meyer found it in Bed 13
on a large fallen block below Whitlands, near Lyme Regis.

Tureritires Becui, Sharpe, ‘Chalk Moll.’ p. 66, pl. xxvi. fig. 13.

The original specimen of this was found near Lyme Regis by
Sir H. De la Beche. Mr. Meyer has obtained specimens from his.
Beds 12 and 13 (see list). At present it is known only from
Devon.

AMMONITES (ACANTHOCERAS) PENTAGONUS, Sp. nov. (Pl. V. figs. 1
& 1a.)

_ This shell has some resemblance in general shape and curvature
to the flattened forms of Ammonites Mantell, but in the number
and arrangement of its dorsal tubercles it resembles A. Deverzanus,.
d’Orb.

Only one specimen has been found, and this is figured in Pl. V.
figs. 1 & la. Its dimensions are:—longest diameter 4 inches, shortest
3 inches ; height of last whorl 1°8 inch, and width of mouth about
1°6 inch.

The whorls are about three parts involute, and the umbilicus is
consequently small. ‘The sides are flattened and the back rounded.
A certain number of ribs, probably about 18, start from a set of
tubercles, which surround the umbilicus, but on the sides other ribs
come in, one or sometimes two between each of the first set, all.
becoming of nearly equal size and passing regularly over the back.

Each rib bears five equidistant tubercles, three on the back and
one on each side of these, where the back curves to meet the sides.
Thus, viewed from the back, five rows of tubercles are visible, the
median row being the most prominent, and the two outer rows being
the least elevated.

The ribs and tubercles are best developed in the younger part of
the shell. In the body-chamber beyond the last sutural line some
curious changes take place ; fora space on the sides the ribs almost
disappear, then the tubercles on the back become smaller, and near’

1 W. Hill on the Chalk of Dover, Quart. Journ. Geol. Soc. vol. xlii. (1886):
p- 242.

Quart. Journ.Geol. Soc. Vol.LII.P1.V.

Mintern Bros .imp

F.H.Michael. del .et lith.

CENOMANIAN AMMONITES.

ae an
eM WY

es Bead SO Me ane ae
Pea ee Ry A Ei

”

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 157

the mouth there is a set of strong, plain, rounded ribs without any
tubercles, which pass over the back and along the sides till they
nearly meet the ribs which start from the umbilical tubercles.

It is most nearly allied to A. Deverianus, but this species, as
figured by d’Orbigny and Sharpe, differs in the following particulars :
it is much less involute and more inflated than A. pentagonus, it
has a much wider umbilicus, there is an extra row of tubercles
along the middle of each side of the shell, and the median dorsal
row is less prominent. Finally the ribs on the sides of the body-
chamber break up into a number of large nodular tubercles.

The fossil now described is a phosphatic cast, and was found by
one of us(A.J. J.-B.) in the glauconitic chalk (? Bed 13) above the
zone of Ammonites Mantelli, in a fallen block at Humble Point, east
of Charton Bay, near Lyme Regis. The name pentagonus refers to
the pentagonal outline of the dorsal surface. It is doubtless a
derived fossil and is associated with A. hippocastanum, A.navicularis,
and Scaphites equalis.

AmMoNITES (ACANTHOCERAS) HIPPOCASTANUM, Sharpe, var. comM-
PREssuS, nov. (PI. V. figs. 2-44.)

The specimens to which we here draw attention may be regarded
as a variety of the above species, but so different are they in general
appearance that we were at first inclined to regard them as a dis-
tinct species. They do not, however, differ from A. hippocastanum
more than some varieties of A. varians do from A. Couper, and in
both cases intermediate forms occur. Messrs. Sharman and Newton
have kindly examined the specimens and concur in this view. Buta
form which departs so greatly from the figured type seems to merit
description and illustration, especially as it is by no means
uncommon on the Devon coast, in the layer of phosphatic nodules
which are often cemented to the top of the A. Mantelli-zone
(Bed 12), and in the overlying glauconitic chalk (Bed 13). It may
be mentioned that the ordinary inflated form of A. hippocastanum
is present in the same beds.

For the compressed form now described the varietal name of
compressus is proposed. The dimensions of that figured in PI. V. figs.
4 & 4a are:—longest diameter 1:2 inch, lesser diameter about ‘88
(seven-eighths) of an inch, width of the mouth about ‘3 of an inch.
The whorls are broad, the sides flattened, and the back elevated.
About twenty tuberculated ribs pass over the back, but nearly half
of these die away on the sides, converging to a row of ten or eleven
tubercles which surround the umbilicus.

Viewed from the back, five rows of tubercles are visible, but the
two outer rows are small and distant. The three inner rows are
set close together along the back and are laterally compressed, so
that the back is narrow and has a very different aspect from that of
the typical hippocastanum, which further differs in having large and
prominent lateral tubercles. Nevertheless varieties occur which
seem to link this form with hippocastanum, and one of them is

158 MESSRS. A. J, JUKES-BROWNE AND W. HILL: [May 1896,

figured in Pl. V. figs.3 &38a. This has only about thirteen ribs to the
whorl, and only five umbilical tubercles; the whorls are narrow and
less involute, all characters which bring it closer to the typical form,
but the narrow back and flattened sides keep it under the variety
compressus.

A third variety comes still closer to the hippocastanum of Sharpe,
being more inflated and having more prominent lateral tubercles ;
the back, however, resembles the variety compressus in the close-set
rows of elongate and laterally-compressed tubercles, so that its
characters are distinctly intermediate between the two extreme
forms. This is figured in Pl. V. figs. 2 & 2a.

VII. Lists or CENoMANIAN FossiIts FOUND IN
Devon anv In NonManpy,.

1. Fossils from the Cenomanian of Devon.

The following list represents the fauna of the beds that we have de-
scribed in Devon, so far as it has been worked out. We have grouped
them in three columns only, for the reasons stated on p. 142. The
bed A of this list includes fossils obtained by Mr. Meyer in his Beds
10 and 11 from all localities except Beer Head, where we regard his
11 as part of 12. Bed B is the same as his Bed 12 plus the 11 of
Beer Head only, Mr. Meyer having informed us which of his fossils
came from the 11 of that locality. Bed C is Mr. Me\er’s 13.

The fourth column shows how many of the fossils found in the
Cenomanian group of the coast occur also at the base of the Chalk
near Chard and Chardstock. This column is a nearly complete list
of the Chard fauna, for there are very few of the fossils found there
which do not also occur on the coast.

The last column indicates the species occurring in beds A, B, and
€ which are also found in the true Cenomanian of the North-west of
France—. ¢., of the departments of the Seine Inferieure, Calvados,
Orne, and Sarthe.

The letters by which the fossils are indicated in the first three
columns have the following signification :—

S means: collected by ourselves or by Mr. Rhodes for the Geo-
logical Survey.

H means: identified by Dr. Hinde from specimens sent to him by
ourselves.

M means: identified by Mr. Me er from specimens in his own
collection.

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 159

Devon. s
a= eS :
sels S
q/m@l/olss|.s8
siolso lsoee
2) i) a .
Ai A; A! {4
SPONGES.
Elasmostoma consobrinum ......cceeececenes oan, 12 en eee eee
Paap eRe eae Mee a he cada da. Ht :
fk rematocystia d Orbignyr Le Widit (gARmAAa SS Bneratone 1 Ea ed ee a
£ siphonatdes, Mich.’ ......0c<0++-00% aes cee | heoteiae Ty
Nematinion calyculatum .........cccccscessecsceseeees je) |
- 5 Rae Se he PERE ig ADE ERE REE Pes H
Hypro0zoa.
MO SPIOIE: {BD ag anc tuinasenncte seni wenn adatvonextaer 1s enn ee ee ee
?Genus (concentric layers) ...........2.....eeeeees H
PRRODUS (UMDUIAE) ce scessdeacosrenees eaeceeteadsces H
ACTINOZOA.
Micrabacia coronula, Goldf. ............cccecceeeees Sy Mb) cS 1
RETINISER 2G: N=. | ves apeseeatnclogeodasseasyatseasieahs H
HEcHINODERMATA.
Caratomus rostratus, Ag. ....... Sseddieasdasteadeaes SMISMISM|... | x
Catopygus columbarius, Lam. ..........eeec cesses So M-| 0 et
Cidaris vesiculosa, Goldf. MUCHE)) costs fos see scumdeoa eas SE Ses eh hea
Su nee (spines) on. % PuaGe a Sdce loadin tugeeeeede S
Codiopsis doma, Desm. ..............eceeeeeens ba Ses Rh WA aah ae
Cottaldia Benettie, campers sa vdede cc ccaaes suas pds hr ie es idee icine
Discoidea cylindrica, Wain: oisccccésccvsclscsacoctcees| oo, S?iS MI x *
- EDUPTINGs Oreo da vat dgaddoc se fds bacd those ete SiISM § *
és subucula, Wein) «ssice2cs.8s3<decceadtensecs SMISM/SM| x | x
Echinobrissus lacwnosus, Goldf. ...............0..00- SE
Echinoconus castaneus, ‘Brongn. UO RPE 3. oo eas S|MISM x | x
Echinocyphus dificilis, fT INAS Ae aR A aan | re | we
Glyphocyphus radiatus, Hoeninghaus ............ ee Peele Da a ee
Gontophorus lumulatus, Ag. .....cccceceeeseeees rea eee eh er le ee
Hemiaster Morrisit, Forbes — ....:....:..ccccececeeeel ... M
WARIASEOR BY aeracessn dara Ssscdecccasshaiccicanseeereten. SM) Ss
Holasier levis; Delite. eizcccceccccsicccccccccdaneene, SMi M!S %
re ay WARS CQTINGIUS, AG. 3 5.252555. Snel oe ye aes
3 suborbicularis, Brongn. .......2.cccesasce CTS ee Rs pe a haa Jama
3 suborbicularis, Wright -::23::..:2cccc..c0.0 Wieck hte
» subglobosus, Leske BesRdeac iecscasaeeee SMISM/?M! x | +
Holectypus bistriatus, Wright. ................0008- soba he at pen ae
Pseudodiadema Benettie, Forbes .................. Joli pdce ada a ER ee
é Brongniarti Oe ries PRR ep ar bn ES te al a a
7 Mechel, Wes 8 i235: .65i2. een vse M|M x
Rs ornatum, Goldf.---:..::..cccceceeeee Sie Rt se 46
vartolare, Brongn. .............5- SM... |SM) x | x
Pygurus lampas, De la FeSO cocci sss, Sa ee twee. | ots. | 8
Pyrine (CUS) Ais fin eoscc sect lcaiteatavscsssceceannes rs aaa lull x
no Desmoulinsii, AEP 22422 aclu eke M * | #

160 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1806,

TABLE (continued).

DeEvon a
uj)
ame Els &
qi/al/Olsel.&
£4 = 4
¢ |e] 2 [Soe
Sia \};A jo |4
EcuHINODERMATA (co7z.).
Pyrina ovulum (2), AQ. .ccsecreceeseeseeuterterecaes ILO I Die ee pe
Salenia petalifera, Desm. .......0-seceseeeeeereeeees ST SME | Tse *
ANAT G000G, CAG. ceeemeeeti rn ens: UR Re x
> Clarkii (2), Forbes .......ccscseeeeeesereecees Ss 8
Trematopygus ?, SP. MOV. ....e.ceseeeeeeeencercereneres cee ve
ANNELIDA.
Ditrupa difformis, Lam. .........c..sccseresseaseerees sore Se 4) AL oe ee
Galeolaria plexus, SOW. .....cccceceeecseceereeseneres SM Feel (aeievey alt age *%
Vermicularia wmbonata, Mant. ....... She elo.s homer S
CRUSTACEA.
OGURA GES SDine sae dep -eiicoeec oso neste sSeeoencsteseree M|M
Pouyzoa.
Hischanarneuscriaca, Mich. 2 he. cne-ewcccenemenenees REET: ih seth 2a] crea AlN se
‘ iOS Wek Cees Ate one one one ome nee, H
GeRiOPOTG Spe U2) \, eee come cae oce- mesyseemrret heen Talsieiae
55 (Si08) 20) Pe-ak nok ca cine vninslnoeeteeeepRe ne seper H
Reptomulticlausa papularis, Mich.................+- H *
Cemocava ramiblosa, MICH. . .....snceereaemeriesesier H *
Defrancia (Pelagia) Hudesii, Mich. .............4 H *
TGR OD ORCA (SNe) mise -Pew close cise +e stadeceereneeerr renee H *
ms S\0n 0) Mande on apceme eee emico coo sso cnecoceee H *
Radiopora (Cellulipora) ornata, d’Orb. ............ H x
BRACHIOPODA.
Crania cenomanensis (?), A’ OrD........c.cceceerecees soe WE * | x
Magas Gemiuci(?), Schloenb. t2is-ctenuscceaseesene M
Megerlia (Kingena) lima, Defr..............00.cs00- SS Mis alee
Rhynchonella convera, SOW. .....0.0cerncernncse-o- SMISM| M| x | x
uh OtHUWaCata. SOW.sc. eee oaks SMISMISM « | x
4 2 var. gallina, Brong. ...|S M| S | ... *
5 Grasiana, a: Orbs cere eee eens SMSM| M *
ve Cuoient idl OV: m.taeerenemeeacecer aca sie il te Pes
- Mantelliana(?), Sow. .........s0.00 Ss 1S
ey ehloenpacks, .Dawasereraeseenenatkel SM M | ... *
a S2g7e, SCHOEN: aerate ene ee eae M
- Westie, Qiwenst.. peceeercae eeneeess SMIS M| x
Terebratula arenosa, WAYCH. .....cccccececcsecsceces M
a OLCUGIU YW IVOOM.. |..0PRePReP Ree REeses:: espe * | *
is captllata, d' Arch. seesk.pacess- isbiieis Ressud ML swale
- OBESE (P) SONG. waicnaueeseebcccamiaedasess eet, ok sual Une
és OVOLD SOW. ....2:55sc eee RRR eset aes S |.M| My... |
_ semiglobosa, SOW. ........0cesceseseenenes Syl eee eo oe
ie squamosa, Mant. iheweteeceeaccs net Ss | M * | %

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 161
TaBLeE (continued).
Devon S
ES ly 8
4 /A/oOls z
i313 (|scee
SliA lA | {4
BRACHIOPODA (cont.).
Terebratula tornacensis, WAYCH. .........seseeceseees| oe M *
PCRMEUT OLAS, ac sascsataaenaske te M|M
Terebratella pectita, Sa Re CN ta Ss | M saan Oe
we MG ORDEV OMIT ac) cn ede rsccbubudaacestes Ss |M * | *
PENA HUI, (Bo Sisicas a ceusiessbuvstaseadunscueenatusdavaes M;M
Trigonosemus incertus, Dav. ....ceccecsesecsecsenees see) ME SEM sae
Terebrirostra lyra, Sow. Pi edeasainne sweet eat a Sirol ee ating aretha Se
LAMELLIBRANCHIATA.
MIDI ANS iain oun douche al ocisintavacdswaneirwtwaaiaeacinantlde S |M
Chama cornucopie (?), CORD iene aeec mates enowenmnoks SP Tass x
PLOGUTE CONLEE, SOW. 6nd eenciemercieaenmwerenws eee S |M x | *
Inoceramus latus (?), dOrb. (won Mant.) ......... SM * | *
fe SERTCLIES: SORVE: « wibraniescaroct tists sioweiclorcierants Ss M * | *
sp. ( elongated) mone eh cbceceon tron peanans 8
Lima (likevntermedia;, COED.) Cccwccmqcenivacmanceal ese Mew) 288%
Pe FLO UDSI SOW Heke Lucente wstoniennraiiowisisaerenin eae SF eR RHATSO Leese
oe RGIS, UO | OR IR SOS SE nna SM M|M| «| x
PE GE GOP case ae berciswins lone ormmpiuisnmionicn easel tees IE see PRE sag he
Be POLOTICLICTISES, AOE) a torirwreicsrortowwewetaeneinias ME ieee a (ae ae
Fa | MSCHELOTINOLG, GOED) Jain cnnw-aveiswisienanecrearnictmer SM M wel Ah ae
BY PP SCRISULCHGE,, CODD: icanicncencmannasedsdaceed« Minas x | x
PURER SU ICT AMOI. i oe cuntanpriwrsansiawian, sea cet eeer S M| ... AC a
PRPC CUE Dg a 22 detec iiicreioniatnnemenn ston eivenceene 1 ae a
sp. (with PIGIEM STOOVES) wns ccinmnicnirnmaenen Se ea
Lithodomus TUTOSUS, A OF ceomeniouprivnioww wows satanten SM... * | %
Modiola (Mytilus) divaricata, V’Orb. ......++4... Mle yea Ee
4 COPA, 2, ZAttel ...0.0.000e<ves aah ME
ye if Guerangeri, @Orb. .....0.-+0 CSU IM Te ue iliac geil ita
os ce VOTRE SO Wa 9 toes ccrom assure S |SM S| « |] «
x 4. ViGeriensts, COLD .....ccoe«esdacene eee poeta ase mame RE
- ie striatocostata, d’Orb. ......... Mi “esa *
p (? genus) arcacea, Gein. .........seeecneee M
. irregularis, CECI. jo eoaseasacneeenlMaee M
Janira COUMOSALG, PIAA, 1 sigan cu alpioeisscsposetene SileM MB | cayt 3
QUAD TICOSLATA, WAM... cecccersciesvavesesadens See ewes Sagal 3
PARC OIA UANANN Ei oecannieasanvevsvenedanaal 0% ES) ee
93 QUINGUECOSLATA, SOW. . ..-...ccecesovesessosees SM M/;}M| x | «
» aecemcostata, Miinst. ......... ieee rae M
BEI is che a syn Rtsrasieninins) Amends; ddewesicdeh dant M
Ostrea carinata, Sow. (frons, Park.) ............ SM| M x | *
fp EP PORORRITI «NUS, (oiscccnmaiscweicamoornerieds tes SM} M ee
hh eee a TERE PATS Ce oi. ansonesesccddadedeont SM... paint de
Se SUE TTI a osds a ccbcieccvsecssacsteues tL eee * *
Pecten asper, MRR eS Slo scistidead cGiive cs senwcanves SM ? * *
gh | MIRNA MEO aetna os aes oceeesescaeaus M;|M
» elon atus(?), Lam. (or new sp.) Brae Sun Sie *
ly ETI OP oes cveecsscccccenscas SN me *
9 orbicularis, Re Sitevesncccncsvenstne 8 *

162 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

TABLE (continued).

Devon. S
Ca) @
, SEIS g
aja |s feel: s
¢/e|e oes
sin; a lo 14
LAMELLIBRANCHIATA (cont.).
Pecten. Puzosianus, Orb. ......s.cseecsccerceveecess Sy *
Seale RISA SACRA La nas can See eee ac eco M
Sl POLOMAQCNSIS, ML OLD... a. ceatakanaaeiomeachie Mf one ih neu ee
ON MASISURCULUS WE. phadiishc..0 case een eee ae4e SM) ews] -= | aes aa
HL PESUOUNLCTSOnZALUG: CUNTCI.) osncraenatuaennaviae: SM M
PR CAGUUG DORGLA. SOW.) | wiusiactcaranaganecntelea sack <o\| SM eros
Spondylus Dutempleanus, CORD eae teradentaonns S|, eee sees || een
S: Oia t il Bains .. ikea aiuto ateee: M
: SERIALS OOM © Sn cohdaemernen ec eC du toa Sill: *
Anatina lanceolata, Eine) co N Eee ae een saree M/S
Arca, Mailieana QO.) sccsnescacecasnpencposerensine pac | |; Mis) eaaliaae
MG IILER I NA OLB, tain cveceoasy elie. duncwacneecte wc] AME ih veie ol en
BE Migeriensis AGIOrDe (abe se aes bakes nakeeeee ae se 7 coos: 9] a
yer Gyprinotdes Id APCD, .siccar-nenzdapesenenase M
bis oninchis, A ATC. ...scscncsnenseuisvesceout® M
Cari PO (CASU) | sane rodsesensoconcesepe ann cbdeeree ase selena YOR ese
Cardium alternans, Reuss ..........ccsccecseecesees- M
ne naluracewm (Gold. wy. 5: esssacaeseaceeeos! M
a oulicanin OOrb:” \aksree wien tice .eel iat M *
Pde pen OnUIGs SOW, , saiccevsucsetestmacoscee Na js | feck bs] eee allie
CorGrs Tacyudatas GOP. vsasc-nsderensennereces ds. SM) 25) ces age ae
Crassatella vindennensis, VOrb. ........-..seeeeee| -2+ Mon) desta
g ligeriensis, G’Orb. ....s--00-00- eae ee: soe | ke! *
GACH COASD: iat ah seers tok» clicas heen deen orp te seen Ss
ITE SILOLIETIG, BSYee aide caw cds san spaceangene sense ce tga SM
Tucina turomensis(?), W@OrDb.._...c.cce--c000.- 000002 BS) fei) Miles aliage
CEOS On OS ape AE CREPE ISS) 85 Auh a2 aern A SUE Ce apsal eet ae
CCEICUVUS LENSE INAS.” | xnnnsoncnapnnerneeccar oe-nce IVINS) wie ‘sink dae
IIOLEIUMCODL GUIS, GOLD: | 0 baie assnkedeu neebeern ce eesaces MW eos A can) Se
TTEGOWUG CYONIS, SOW 2 eas <noiisn-nacecueterpr aeleee <ae Sin) MG)... ae Bee
Ga CpSHUGeNa,, NVC. |, ni: Soonmepeeeneerees: aetees M
Rea nenenilata Tuam... ...cceeeeeee deacon ned su Be empl see?
~ crenuliferd, UVC} sn ssp peer eee eee tec SMI .. ?
* TET TISS | Th EE SEROTEC = Se Pe M
, dunscombensis, Lyc. (sinuata, d’Orb.) .| M | M|... | ... | *
ss VICTOR. WC: 0: 0inscebbeePEReeeeteencensooktt SM) iol Sethe
a PICRITGLE, (SOW 5 .<c:upeReerermeteebeacmuuenice SM
. SOTERA. ic sin RRP hase athe NE are eddie craiemee
S SH CUMITIA MOAI, Sere eee Nei sco 0c LE IME, g) MO pee *
" Vicaryana, Lyc. (spinosa, d’Orb.) ...... SMS) scaly oe) alias
Pholadomya equivalvis, Goldt. ........ccccceceeeeee tare va
MiherisSowervye(e \y WvCeM., ..coseserbersesbeennnnuett Pee rr sieh tee csp. 3
Unicardium ringmeriense, Mant. .........2..0.04.- M/;M| «
VieRUsiG Ola sissy, AGEIN, |... .cccaee mere tcreaneciaoieiovins M
GASTEROPODA,
PA BONEN GIS et heeds yc'uee' suaneace ease pnenemeoceeyccel Sai S

AV EN GE COSSTS, 1 OND: \.x sacwettpetieenennieseekent .. (SM) S| x [| x

Vol. 52.] ‘A DELIMITATION OF THE CENOMANIAN. 163

TABLE (continued).

Chard and
Chardstock.

GaAsTEROPODA (covt.).

peueiand Prevostz, GW ATEN.. ..cccecceccnnccevenscsscses Sea, nae
Lo STERIL TLCSES OaB Re BROCE eR SCE CR CREPE PEC S/|M
Emarginula Meyeri, Gard.
PSSST ae haste dccaseunsseecesknessdecsestesceewe was S MSM
Marece Gauuliind,:& Orb. ..22.2...c dese ssdeste ee donee. 8 x
i BR ey ie
Nevitopsis M
Nerinea Sr
Pleurotomaria Cassissiana, Q’Orb, .......c0ceeeeeees| eee M
Mailleana, VOrb. ....0...0+ Palas M;M
CE. gigantea .......00 eeeatetesistaiel = SMe...
PRhodani, P. & Roux Aad LSet we Os
: M

M

bh)

‘soroods [R19A08 ~

”

SEES, ee)

*

Pterodonta (several species)
Rostellaria Mailleana, QW OrD. ..........ccceccencecees M
SOLAT LUM?) OTMALUNE, SOW. 222. 2htssckeeeenassesasecadecl) oss
g Thirrianum (?), d’ Arch s
eechis Girondins, A Orde s22...2.20c8se.tecesctecene| ace
sp. (like cirrus, Woodw.) .......... Pee fice hectic
' sp. M
Turbo GRerangert, @ OLD, vecceascsdccsesesccoseveaeh ie
» (six other ee
TAME EETELT TG) Re ie a bE ed Aa Aa faces
| Turritella be hi BOD. fesvveistevevesectesecseactes M
M
Voluta Eee ie GOODS aay yee ees leila es

mis

3?

CEPHALOPODA.,

Belemnitella lanceolata, Sow. (non Schloth.)
4 plena, Blainv.
Nautilus Fittoni, Sharpe...........s00+8 Bebo wine
expansus, Sow.
Deslongchampsianus, V Orb. ............06-
Fleuriausianus, d Orb.
Largilliertianus, QOrD. ......+11seeeseeeee] one
levigatus, d’Orb.
Ree SUUrAIEALUS: (2), GORD, © scnnanseucke see «avis
Ammonites Austeni, Sharpe
complanatus, WEP AMG Mase eter wads we. cncces
curvatus, Mant.
euomphalus, Sharpe
FANCOUE, MAME vane ocnuds sclcansseavecrsest SM| M
Goupilianus, GOLD. ....ccccssasesssccces| pas
VAP POCUNGMUNE so casssnecvcvaccicéccavecsa| ens
laticlavius, Sharpe

*k

* KK KK KK

Q. J.G.S. No. 206, N

164 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

TABLE (continued).

Devon ~
ree
SESE
aja |S leal§
3/E|y SOEs
Ala; A |O 14
CEPHALOPODA (conzt.).
Ammonites Mantelli, Sow. ......seecesscseeseeseenees SM| M|...| * | x
" NAVICULATIS, SOW. sccvecsecacevecrescs ces! SM| M{|SM| x | *
i PENTAGONUS, SP. NOV. ...0cceceee-aecscaces| o+- oe has!
i. PLA NALALUS SOW. 2 dcancsicsepeicicas' -nace%. Sj|...]/M | *
2 QUEECEUS AS MATE a... teeing anasto sence ce: 1 a er *
aa IREMEUTENE SWAT PO) <n snacissetwasewetce aces wes | cee | Ee ae
a POLOMGERSIS MDC a sc dederar ee sceeaerss| | as | M\|SM/ x» | x
" VOMLAMSH SOW st cond verve ccere eaunanieens « S|), Es | cial ee eaian nee
3 # var. Coupei, Brong. ......... SME IME) i. Bea ee
- Weestat, Sharpe (? =dispar, d’Orb.).| S |... | .-- | * | ®
Scaphites equalis, SOW. .........c..sccsesenseccnesens SiSMSM| x | «
r .: var. obliquus, SOW. .....-..000- nae Mix | *
TUTTULEES -BECRCUISOWS _ Sicvnc@emancicd secebereeremacse\) wes M|M
‘ COSTOMUS, MUATIN, san site caeuiotaiseee apse ae'sniees S.| ML | «=. ei eeeaalneee
r Gravesianus, OVD. ...cccceceeeceeeeraee| oe M
- WMORTISIL, SRATWO ..0 cna. ceseesene se esees | is M|...| x
33 Scheuchzerianus, Bose ......0+..es0e-0e- Ss aes) || \neeen eee
‘ PUVETCUNATUS. OSC. vi. cccan saws -nesesenteins S Mix | x
Hamitestsunplex (0), A OXD, ~ pecneosesase+seennsaves Ss M *
Pisces.
Lamna appendiculata (?), Ag. c..coscescossessencers Stale as
PiyChOMUS ACCUrTeNs, NG. sisocactseneasecnes scence. eal OL
ISCO PIMIL CU ICUS caticecig-1snleenearnslee ceeds cies 1c 8
Ss

Onunhing Mantel, AG... ..-sccreevenadeasesseses.s

From the above list it will be seen that the fauna of the Devon
zone of Ammonites Mantelli is the fauna of the Cenomanian of
the North-west of France. There are 10 species which are at
present only known from their occurrence in these beds or near
Chard. Deducting these from a total of 195 species and varieties
of invertebrata, we have 185 which occur elsewhere, and out of
these 132 are found to occur in the Cenomanian of Western France;
while some others, such as Hchinocyphus difficilis, Magas Geinitzt,
Ammonites planulatus, A. laticlavius, A. leptonema, and A. euom-
.phalus, ete., occur in beds of Cenomanian age elsewhere.

Moreover there are 4 echinoderms, 18 lamellibranchs, and 6 or
more gasteropods which are not known to occur elsewhere in
England, but which are common to this Devon deposit and the
Cenomanian of Western France. Mr. Meyer’s collection includes
many species of gasteropoda which he has not been able to name,
but we think it very probable that, if they could be compared with

Wel s2uf/ A DELIMITATION OF THE CENOMANIAN, 165

specimens from the sands of the Sarthe, many of them would be
found to agree with known Cenomanian species.

The Devon fauna has also a strong affinity with that of the
Tourtia of Tournay, in Belgium. Several Tourtia species occur
which have not yet been recorded from the Cenomanian of Western
France. These are TYerebratula arenosa, T. Verneuilii, Pecten
Passyi, P. subinterstriatus, Spondylus Omalu, Astarte cyprinoides,
A, Konincku, Avellana Prevosti, and Solarwum Thirrianum (?), nine
species in all; besides two species which we have for the first time
recognized in the Western Cenomanian, namely, Terebratula capil-
lata and T. tornacensis.

In order to compare this Devon Cenomanian fauna with that of
the Warminster Greensand it will be necessary to examine the chief
collections of Warminster fossils, not only for the purpose of sub-
mitting many of the species to a critical examination, but in order
to weed out of them all the specimens which are preserved in phos-
phate of lime, for these have really been obtained from the overlying
Chloritic Marl and not from the green sand which lies between it
and the Chert Beds. This investigation is not yet completed, but
we are able to state that the Warminster Greensand contains
comparatively few gasteropoda or cephalopoda, that Ammonites
Mantelli and A. navicularis are rare shells in it, and that Turrilites
costatus and 7’. twberculatus do not occur.

It is true that many echinodermata, brachiopoda, and lamelli-
branchiata are common to the Devon and Warminster deposits, but
these are shallow-water forms which would be likely to survive, and
to be found in the shallow-water deposits of a slightly later date
than that in which they first appear.

When the fauna found in Devon is compared with that of the
Lower Chalk, say that of the Isle of Wight, we find a relationship
of just the opposite kind. The Nautilr, Scaphites, Ammonites, and
Turrilites which are commonest in Devon are also those which
abound in the Chloritic Marl and Chalk Marl of the Isle of Wight.
Moreover, there are other species, such as Ammonites Austeni,
A. complanatus, A. euomphalus, A. Goupilianus, A. laticlavius,
A. leptonema(?), and A. Reneviert, which are much more rarely
met with, but which have hitherto been found only in the Chalk
Marl or in its basement-bed. When, however, we turn to the
echinoderms, brachiopods, and lamellibranchs, we do not find so
many of the Devon species in the Chalk Marl as in the Warminster
Greensand; but, as no one doubts that the Chalk Marl was formed
in a deeper sea than the Warminster Greensand, this absence ot
certain species is not to be wondered at.

We would remark that a mere percentage comparison of the
faunas of two deposits is not of much value in determining their
relative age, even when they occur within the same ancient province,
unless there is good reason to suppose that they were tormed in water
of about the same depth. If, on the other hand, one is a deposit of
shallower water than the other, the creatures which are most affected
by the difference, such as sponges, polyzoa, brachiopoda, echino-

N 2

166 MESSRS, A, J. JUKES-BROWNE AND W. HILE: [May 1896,

dermata, and all mollusca, except the cephalopoda, must be neglected
in the comparison, and with reference to geological age only the
cephalopoda should be admitted as evidence.

2. Fossils from the Cenomanian of Normandy.

The following list contains only the fossils obtained by our-
selves at the places named, together with a few others for which
we have the authority either of M. Lennier or M. Lecceur, and a
few occurrences of particular echinodermata mentioned by Wright
or in d’Orbigny’s volumes.

A complete list of Cenomanian fossils, including those found in
the Sarthe, would be a very long one, and would not serve any
specially useful purpose. ‘The present list may be taken to include
all the commoner fossils of the more calcareous facies of the Ceno-
manian in North-western France, such species as would generally
be met with by any collector. <A full list of the fossils found in
the Cenomanian of the Sarthe has been given by Guillier.’

For the identification of the sponges, polyzoa, and hydrozoa we
are indebted to Dr. G. J. Hinde, F.G.S.; the other fossils have been
determined by ourselves.

The first column contains all the fossils met with in the Cenoma-
nian of the cliff-section near Havre, the second shows those found at
and near Orbiquet, and the third those from Vimoutiers and Lisores.
Tt; should be mentioned that many in this third column are specimens
given us by M. Lecceur. In these columns fossils examined and
identified by ourselves are indicated by asterisks; those mentioned
by others are indicated by letters—L standing for Lennier, Le for
Lecceur, O for d’Orbigny, and W for Wright.

In order to compare this fauna with that of the Warminster
Greensand on the one hand and the Lower Chalk on the other, we
have indicated in the fourth and fifth columns the species which
occur in these formations. By the Warminster Greensand we mean
the sand lying between the Chert Beds of Warminster and the
Chloritic Marl, and, so far as we can ascertain, 58 species out of
99 are common to the French Cenomanian and the Warminster
Greensand, polyzoa being excluded.

The Lower Chalk of the fifth column is regarded as including the
Chloritic Marl and the basement-beds of Dorset and Chard, but does
not include the species which only occur in its representative on the
Devon coast. Such species as only occur in the basement-beds are
indicated by the letter B. Including these, 63 out of 99 species
are common to the French Cenomanian and our Lower Chalk.
Polyzoa are left out of account, because the Cretaceous species are
greatly in need of revision, and it is uncertain what species range
into the Lower Chalk.

It appears, therefore, that the percentage of Cenomanian species

1 « Géologie de la Sarthe,’ Le Mans, 1886.

Vol. 52.] «= - A, DELIMITATION OF THE CENOMANIAN, . 167

occurring in the Lower Chalk is a little larger than that occurring
in the Warminster Greensand. We do not, however, rely greatly
on this method of comparison; as already mentioned, it is to
the cephalopoda alone that we look for reliable paleontological
evidence regarding the age of such different deposits. Now the
Cenomanian cephalopoda in our list number 14; of these only 7
occur at Warminster, while all of them occur in the Lower Chalk.
Further, of those in the Warminster Greensand all except three
(Ammonites varians, A, Couper, and A. falcatus) are rare fossils,
while in the Lower Chalk nearly allare verycommon, This evidence
is very strongly in favour of the view for which we contend, and its
force will be further alluded to in the sequel.

NorMANDY. | ENGLAND.

AY| Bo) ©

D|#
Tc Pyle | mar ibs ~
ac] ¢/3 2is s| s
cole lest Sy | DM
ols ElsS*ol]g ai ©
SSS 2/8218 3] 2
Hl else lee! 3s
Olea] a0) E
|3f Ps = io}
= es) 4
PortFerA (SronGEs).
Corynella rugosa, Hinde ........0.ccccesseceseeseseees SE NA aR, cas! (Ni
210 uk ae a Gee na ace feann sadehees *
Elasmostoma consobrinum, a’Orb, siaetataes cine poles eee ac, |
Pe plicatum, [2 Clee AA am ee
Trematocystis siphonioides, Mich. .............s0.08 PE ze eee
ne POrbighys, TNC © 5, ...cs20+0040855s Ue duties, yack
TIERED Uae h oe Sst Ph Sa one Seca aie sivons's 0 «dese aba
Pachypoterion compactum, Hinde ...........0.00.6 He icalee. lime |
Plocoscyphia, sp. (tragments) ..........s.s.ceeceeevee gaa Ny oe
Stauronema Carteri, Sollas .......... suaneeneeneee © Seal dhs ig ee ieee (3°
Hyprozoa..
Porosphera urceolata, Phil. ....:....ceccceeecccconsens * *
33 Sp. POSH HTS HOHESHEH ESSE EEOHESES SEES OEE EE *
| AcTINOZOA,
Micrabacia coronula, Goldf. s.s...:c.scsseeseeeeees- Meese fossa) | A.
ANNELIDA,
Ditrupa difformis, Lam, ...... ateadregea ieee tas Pre ty ia Inne * | *
Galeolaria filiformis, SOW. seiceccccecersececceeeeceee] one * * | x
|) lewis; BOW.” sapcccees ERER AE SSA UEP EC | a * | x
CRUSTACEA.

Scalpellum ......4. ssp co ehi Preset testi eesesscssies *

168 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

TABLE (continued).

Normanpy. | ENGLAND.

ao) .jn2ulgs “4
a. =| 0/9 £la 3|
Se pers Sikes 2 GS
2)S)| 3 oS 3).2) aie
-o => Z, 5 S J a ~
Oy H/F 18 | ©
RASS = eo 3
s =
EcuInoDERMATA.
COTALOMUS TOSTRATUS, UNO. ois ses (aannpaeaitsida cab owas * | oe *
Catopygus columbarius, Lam, ............seeseenecees * | * | * | * | B
Cidanes wesiculosa, Goldie). .ccsacsssscccsscccsese<e. * see |
Cottaldia Benet, Woemie 0 ..c0acracesoenaraseras- one ||| ee
Discoidea subucula, Leske ........ssecceccececccesces *x | * | or *
WptOsleTiCrOSSISSUINUS, DEIN perce seececanencte+scrcee: * | ok | ea) Seas
Gomophorus lumulatus, Ag. s.inccsscecsesnsersonss. WwW. W | x |
PATLOM SIU Bsclas cpisewocenarsavatsaieeacinne sees *
Glyphocyphus radiatus, Des0r s.ssssssscssvecsesee * |... || due *
TACTHOSLCE OW) O, WWESOY Sraececsdceanivnoveas senses: OM ee a
TAN GSGCNICAEINGUUS (UEUES)) \a. sachucweesnoneeesasisnee: * | K | oe | HR |
im subglobosus, Wiese: 4, .nceesueseuesneuae Basel Rid). gio wee, alee mek
Peltastes acanthordes, AG. ...ccdenerenessudasdoasvcde Oat tle O
Me CLOUT OLUS NOs, ca PEt es ckeaeh eas W | oasis ce), ele
Pszudodiadema ornatum, Desor ............ pe i Kl es | Oe oe
fs Benettie, Vor besieenisscdee sess: ca Wa | 1)
oF Wormanimie, Cotte wesesceddesdecose ide Ww
5, Machete, News Vneeee ee cers coc WW eke
Vartolane, AG raat icetes ce A OR ON ea ae
Salenia Clarkii (?), Wright seiovadtdryoementey. | cee | eee | vee | # :
ped wpecalijena. Ng © |S A eenseeeacas eoeeae | soe | one | HB |
pa CULIGeT a(S), Gray <sameceeenereeeaes Wiese oF |
Pouyzoa.
WALLETS ID | Wctoiocltsiininainij0a.e slo 0 nelebcloepreisele uciastcleiseison *
Cerropora i(Ceriocara) mammillaris, d’'Orb, ...| *
WT ESTGPOEC MSG 62's (te sis «vats seta eannepetatchaki is cieel: ves | cee | ®
‘3 BD MOM eis els ciajoe clone PROM eeee ea ciccinassy *
BRo Giidwaid-dassdaacoupenenenivannacnencycrns *
Entalophora mamosissuma, WOLD. , secves.coece.--00e seh \hidoesta| er anaes
PCL ENOMOLORS De) bse: Bis osincleadeepmepimacenrariscianiadseini *
Sparsicava irreqularis, CQ ON Dspace tani aelntinetes *
Melicertites compressa, d’Orb. ...........++ si rcaincecan #
gmnoneusromosas Wich. \,chicesecementoesace cee cee a: *
lnoaoporawornata, a Orb, Vi-seseatneese-ate-s6> +25. %
a pubereuiata, OC Oxb.iremendeectecde= sees: x
Micropora, 5 Species........-s..eeeseseesererercereennes x
LING OSI Si aI eS A oiedill sesiaunl ane
Reptomulticlausa Populares, Migiy ewer sacdsces+=5- abi le aise le eagle
BRACHIOPODA.
Megerlia (Kingena) lima, Defy. ..........0.ceseeeee- 3G sews, Yl ae de

*
Terebratella peciita, SOW. | scceuvesdseusarascsenaces: % | sisi |) ccohll Mame

eb 52. | : A DELIMITATION OF THE CENOMANIAN, (169
TABLE (continued).
ee aE naar ees

NormaAnpy. | ENGLAND.

oe p
z = +l] m x 3 = =
o2| 2) 8-2/3 21 4
eo] oS4 2a)
-O =) ~
ae aol es = om 3 2 o
e2\SOlR Glad) &
ae ie oe isa
BracHIopoDa (cont.).
Terebratella Menardi?, Lam. .........06 Ascii ah ates *
Terebratula arcuata, Roem. ...scscscscseeceeceseses lace (Pasa ease Ws
4 biplicata, Sow. ......44+- paradiaters ede. Aes iene eB
9 LO PUUAAs DATED 5c .08 snnvoancceenessias Mecsipieas dae se), Wear te
Pr QUOTE DOW f Masiwasvasinacackedn es anpaden ea hPeae. | ot *
Denebrirostra lyrd, SOW-\ .....0-cccessceseasceassasaees L |... *
Ehynchonella converd, SoW.......c0ccesescsecssseeeses 30) eae ade eae
‘3 BUNGLE! SOW ssscccesscstscesetadisaes Ko | vee PI eae eB
% Grastangd, VWOrDsedesssdccctocasn savas FEE 1h EON a Ts SA I
- Schloenbachi, Dav. ..cccccccccscseeee cae A ee (ee ?
3 Lamarckiana, V@Orb. 6.0.00. Ruelpiwe ah ses DMLUG
LAMELLIBRANCHIATA,
Ostrea canaliculata, Sow. (= O. lateralis, Nills.).| « | * | * | * | *
We. CATINALG, SOW. deio.c-- PA AACS CREE ae ae eee adem eee *
» hippopodium, Nilss. ........ Seis vis b eee eo roe
Pee Leste rr GROED: When ges eden vassev ess Lange Danse Pes ty Serle ae
Fe, VESICHIOTIS UA, os crtadacteotad nests viacstageaagen * | * | * | * | *
MESTEULOSE, (VAL). onaascrsen> etedetes sbaeae Meceeolcem | Mine |
Exogyra CONMCH, SOW. ..-00460 semisiaataera ae Saaaa tuna x | *« | * | * | *
ie Rauliniana, d’ Orbe. at, Oe Re ote ee a a
Pecten asper, Lam, .2....006000 senaadtenese Ansincaeetlaee x | x | «| «| B
fy 1. elongatus, Lam. ....s- diddetahnaanaes Jee al a a ary Pe | ae (Me
ee LCDI, A III y ty saicisrerctorarataicitatete sions tha | * x | B
LOR OICULETIS, SOW E \hinenimacrnestactesterararcre dhatear alate Chi! coat [ALN TRIS 1D
» Luzosianus, Orb. ....... dotatewaneases dentate Bea" licks Puce tLe
POPs Le gaceeben <M catewdcactantnaictttetsentctedeta dated da * x | %
BUA Gael hag Machiwwanaantatdamennnr cares sds SOR RT Oe
Janira quinquecostata, SOW ss clasdesrerdaencenrairaattasinndiens He Le fatal PP eye] © 9
99 Qed ricostata, SOW. .....sceeceere siscbebstere tas * | *
- equicostata, COR bsionsatooes: Lalasitstnvactaaien * | * | * | *
Lima cenomanensis, W’OrD. ......cccsceseeceseeeeees Dire othe ; x
FRCL POU/OPI1013y, OF OLD di desa vena sennasnesovce Sah L | x
yy sempler, VOrd. 2.c0ccc0 Be CORR eer. & nth) eee a
3a) SCMUOTNALA, A OED occ sewansns« pesca 2 snargueel Ca Se re ue aaa ee
Inoceramus striatus, SOW. ...ccccsccsccseseecees seneal tee bee |, *
Spondylus striatus, Sow. .......... Pe BEE CHEE Hoes: eee | oe ae Le
Mytilus ligeriensis, d’Orb. . sea vwbncuudea eae io
Trigonia spinosa, d’Orb.= Vicaryana a ahs Sa ae ad ee der Mg
J crenulata, Lam. .........- dasatbaricemmaeee *
Arca ligeriensis, ile, i ope aa he | ne |b
Corbis rotundata, Q’Orb, ..........2.4.+ share suse * 4 |e
*

Cytherea plana?, Sow. .......eeceeee: e¥acsitocwnces

170 MESSRS, A. J. JUKES-BROWNE AND W. HILL: [May 1896,

TABLE (continued),

Normanpy. | ENGuanp.
Al BC.) Daa
td
o 2/8 S/S 6|2 I 5
> 1g O19 w 25
t 5O FS, | ai Sees
|| 8 Beran) =
am| Cl ss iS
= 3 S |
LAMELLIBRANCHIATA, (conz.).
Cytherea, sp. (small) ....csceccseesceeeeenecececennees 1 cee | sen fl), © Oe
Cardium Hillanwm, Sow. — ...ccccsscccsccsccsereccees eee Mi eed ae B
Cyprina ligeriensis, WOrd. ......s.cce-seeeeeeeeeeees pepill Mok whee
GASTEROPODA.
Avellana cassis, .d’Orb. ...... Wee onan siniaivienieenee ee ee ote
APOTrhGis, BPs eas on-eee-taeaaynaane Sess aSeRINON 190 9° *
Fusus Espaillact, @Orb. ......+.++. tiie aise a oe kGOE saath PES
WNaticg, gaultind, DOWD. | ...crtncsse<cause+s+sppeeonne- EW) pee dl. ons *
Pleurotomaria Archiaci, WOrd, ......+.sceeeereseee: L :
“A Maitland Oran cin-.nte-sn.c0ene: L * | x
a perspectiva, Mant. ............ Soneee Li | .ce dace ee
E) OBIE Sande 95 -nid9 0955 isonena Isa SoneeSee % eae ee
Turboidea, BD) <i-nencceeebeeneer Mepgeters 259-5 A Bea *
CEPHALOPODA,
| Ammonites varians, SOW, ......cessecsacecenees Re a ee ee ee
“ 3m VaR: Coupei, Brongn. as... we} S36 4) lace west See
5 Mantelli, SOW. . occeeeeeeererreesees aes ee ee
si paviculacts,. MaRty ee aascsssernccconssesns x * 4 Re
|. palcatas, Mant. ..- seers Bencan ce kris sees x . | * | * | x
» .rotomagensis, Brongn. .......+..0.00000. So eer *
cenomanensis, G’Arch. ...00...seeseeeee: etl Fgh Reel ge *
Hamites sumpled, COrp. ..-ssseereereee eceeeeeseereee Pei see lp x
SD, cpeclls qvesta cheep seieeeeee Sasa aa eeee *
Turriliies costatus, Lam. ..... eat pba wari Al eee]. Es A eae
as tuberculatus, Bose ........- ee % a seu | dl eee
Baculites baculoides, d’Orb. ancinise enema ted. me ee eee er * *
SEADNILCS COUAIIS, SOW. n..erceeeterectentenereceeceet ae Ree *
Nautilus elegans, Sow. ....--.s:eeseeseerces is RT a LO ison See
i. subradiatus, VOrb, ........sseeee: peewee ia OF * | *

VIII. Summary anp Conciusions.

It is now recognized by the Geological Survey of Great Britain
that the Gault and Upper Greensand can no longer be regarded as
separate stages or chronological divisions of the Cretaceous System.
To speak of ‘the Gault’ as a formation distinct from and older than
‘the Upper Greensand’ is simply a mistake, for there can be no
doubt that what is called Upper Gault in the East of England is

Vol. 52.] A DELIMITATION OF THE CENOMANIAN. 171

coeval with Upper Greensand in the west. They are merely
different lithological facies of one group of deposits, and in the
systematic classification of the future a new name will have to be
found for this combined Gault-and-Greensand formation. It is
much more developed in England than in France, and its name
should be taken from some English locality.

On the other hand, we claim to have shown in this paper that

when we pass from the Upper Greensand to the Lower Chalk we
find that the change in the nature of the deposit corresponds with a
great change in the fauna. This change is particularly conspicuous
in Dorset and the Isle of Wight, where the base of the Chalk is
always marked by the abundance of ammonites belonging to the
species varians, Coupei, curvatus, and Mantel, with Turrilites
tuberculatus and J’. Morrisi.
_ It is true that in Wiltshire there is a more gradual passage from
Greensand to Chalk, and that some of these cephalopods do appear
in the sand just below the Chloritic Marl, but this only shows that
where the record is more complete we find a few forerunners of the
Chalk Marl fauna coming in locally before the time when these
species spread over the whole marine province.

We are, therefore, very decidedly of opinion that in England
there is only one plane of division in this series of beds which can
possibly be taken as separating one natural group of deposits from
another. Further, seeing that. England and Northern France
formed part of one and the same area of deposition, we should be
much surprised if a change of conditions which introduced a new
assemblage of cephalopoda over the whole of Southern England did
not show itself just as clearly in the North of France.

Before passing over to France, however, we described the sections
to be seen in the cliffs of East Devon, where the Chalk Mar] is
represented by glauconitic and quartziferous limestones, rich in
fossils and yielding an assemblage of species which more closely
corresponds with the Cenomanian fauna of the Sarthe than with any
other local English fauna. Moreover, the position of these beds is
perfectly clear, for they are plainly marked off from the Upper
Greensand, which is at the same time fully developed, and they are
overlain by a complete Middle Chalk or Turonian stage. Here,
therefore, on English ground we have a diminutive ‘ Cenomanian ”
deposit, part of which has an arenaceous character and a peculiar
shallow-water fauna connecting it very closely with the typical
Cenomanian of the Sarthe.

Our next study was that of the fine section exposed in the cliffs
near Havre (Seine Inférieure). Our object was simply to see and
decide for ourselves how much of it corresponded to the Gault-and-
Greensand stage and how much to the Lower Chalk. We have
indicated what seem to us the obvious and natural divisions of the
series near Havre, and have pointed out that our interpretation of
the section agrees closely with that of M. Lennier, who has studied
and described it more carefully than any other French geologist.

- The fact that the same bed is taken both by M. Lennier and by,

172 MESSRS. A. J, JUKES-BROWNE AND W. HILL: [May 1896,

ourselves as without doubt the base of the ‘Cénomanien’ is sufficient
to prove that this base is a clearly-marked horizon. Now it seemed
to us equally clear that this basement-bed corresponded to the
Chloritie Marl of the Isle of Wight, or zone of Stawronema Carteri.
The overlying beds are therefore the equivalent of our Chalk Marl,
and the material of them is a chalky marl, though more visibly
glauconitic than our Chalk Marl. At a certain level there is a bed
which has some resemblance to Totternhoe Stone, and above this
Holaster subglobosus becomes common, just as it does in some parts
of England. About 80 feet from the base is a band of glauconitic
chalk with phosphate-nodules, but there is no marked change of
fauna here, and between 30 and 40 feet above this band we reach
the base of the Turonian.

In our opinion, therefore, the acknowledged ‘Cénomanien’ of
these cliffs is the equivalent of our Lower Chalk, and of that only.
That its fauna should contain a certain admixture of species which
lived in English waters at the very close of the Upper Greensand
epoch can only surprise those who imagine that every portion of a
contemporaneous set of beds must hold precisely the same fauna,
whether one portion was formed in shallower water or not. The
presence of Pecten asper and other fossils which do not occur in our
Chalk Marl is capable of a very simple explanation, which we shall
mention further on.

Beneath this ‘ Cénomanien’ at Cape La Heve there is a represen-
tative of our Gault-and-Upper Greensand group. It is of no great
thickness, only about 35 feet, unless the basal conglomerate or
Carstone be added, as M. Lennier thinks it should, which would
raise the total to 50 feet In this thickness, however, the Lower
Gault (or Albien proper), together with so much of the Upper
Greensand as is included in the zone of Ammonites rostratus (or
Gaize), are clearly represented, but we do not think that any equiva-
lent of the English zone of Pecten asper is present. This zone is so
variable a quantity in England that there is nothing surprising in
its being absent at Havre, where the whole Gault-and-Greensand
group is evidently in process of thinning out.

We have seen that on the south coast of England the zone of
Pecten asper varies from 60 to about 6 feet, and north of Devizes,
in Wiltshire, it thins rapidly till we get a sequence very like that
near Havre, namely Chloritic Marl with phosphates resting on a
few feet of unfossiliferous marly greensand which passes down into
micaceous sandstone or Gaize. Moreover this zone is absent at
Eastbourne, Folkestone, and Wissant, and also in Argonne and
Perthois on the borders of the Marne and Meuse in the East of
France, the Chloritic Marl in all these places resting directly on
beds which are referred to the zone of Ammonites rostratus.’

Passing now to the Cenomanian of the Calvados and Orne, a
section near Honfleur seems to show the Chloritic Marl with a some-
what different facies, for it no longer contains phosphatic nodules,

1 See Barrois, ‘Terr. Orét. des Ardennes,’ Ann. Soc. géol, Nord, vol. yv.
(1878) p. 332. | ;

Orne.

Ammonites
rotumagensis

Zone a
Ammonites
Mantelli.

VIMOUTIERS, —

i zone a

Glauconie.

[To face p. 172.

_ Morraenz,
Feet. Feet. | Kets
TT, ""$6 Sables du Perche| |
33 A gi Ta aes |
Zone a
60| Scaphites
equalis, :
|
115 |
Sables 4
130 Perna
|
“ lanceolata. \
|
Zone a |
80) Ammonites |
Mantelli. |
95| Glauconie. |

‘NVINVNONTO

Quart. Journ. Geol. Soc. Vol. LIT. [Lo face p. 172.
Conxtrartson oF Enanish anp Frencu Sxcrrons.

(Scale: 1 inch = 100 feet.)

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Vol. 52.] A DELIMITATION OF THE CENOMANIAN, , 173

but encloses large lumps or doggers of calcareous stone. From this
point southward a similar bed or a layer of such glauconitic marly
stone seems everywhere to form the base of the Cenomanian.

A section near Lisieux shows the Gault on the point of dying
out, and beyond this place what we have called ‘the Greensand’
forms the base of the Cretaceous series. This is the ‘ Glauconie’ of
M. Paul Bizet, which in the east of the Orne may be 30 feet thick.
We believe that the greater part of it corresponds to the Gaize of
Havre, but the occurrence of Pecten asper in the upper part of it at
Notre Dame de Courson, south of Lisieux, suggests the possibility of
its also including a thin local representative of the Pecten asper-zone.
At Vimoutiers, however, the thickness of this ‘ greensand’ is small
(only 10 feet), and the only fossil found is Ostrea vesiculosa, so that
zonal subdivision becomes impossible. The important point is that
it lies beneath the bed which we take to represent the Chloritic
Marl, and consequently that it is of the age of our Upper Green-
sand.

At and south of Vimoutiers the Cenomanian proper is divided by
French geologists into (1) zone of Ammonites Mantelli and (2) the
‘Craie de Rouen,’ or zone of Ammonites rotomagensis. There can be
no doubt that these two zones are roughly equivalent to the lower
and upper portions of the Cenomanian near Havre and Rouen, and
here we are in complete agreement with French geologists.

Lithologically, however, there is a considerable difference between
the Cenomanian of Vimoutiers and that of Havre; the lower part
has ceased to be a ‘craie glauconieuse,’ and has become a fine
glauconitic and slightly chalky sand, while the upper part has become
a still less calcareous and more micaceous sand. Still farther south
the lithological differences become more and more marked, till we
arrive at the purely arenaceous type of Le Mans.

It is not suprising, therefore, to find that the fauna of these
arenaceous beds differs considerably from that of our Lower Chalk
and Chalk Marl; the physical and bathymetrical conditions under
which these Cenomanian deposits were formed were evidently
similar to those under which the highest part of our Upper Green-
sand was deposited, and hence many of our Upper Greensand
molluscs and echinoderms continued to exist in these Cenomanian
waters. Besides these, however, there is a certain number of species
which are peculiar and do not occur either in our Upper Greensand
or in the Chalk Marl, nor in the ‘Craie glauconieuse’ of Havre ;
but some of them do occur in the Cenomanian of Devon.

The beds which we have termed the ‘Cenomanian of Devon’
offer some special points of comparison with that of France, besides
the striking resemblance between the two faunas. The minute
structure of the bed numbered 11 by Mr. Meyer and of the upper
and less arenaceous part of Bed 10 is similar to that of some beds
in the lower part of the Cenomanian of Cape La Héve and of
Vimoutiers (see p. 140).

Bed 13 of the Devon series has, however, no analogue in France,
unless it is to be found in the famous fossiliferous bed near the top

174 MESSRS. A. J, JUKES-BROWNE AND W, HILL: [May 1806,

of the Cenomanian at Rouen. We have not seen this bed, but it is
described as a glauconitic chalk containing phosphatic nodules and
many fossils, among which Scaphites equalis, Baculites baculordes,
Ammonites navicularis, and A. rotomagensis are common. It is
remarkable that phosphatic fossils of these species abound in the
bed which overlies No. 12 between Axmouth and Lyme Regis,
Some of them are also common in Bed 7 of St. Jouin.

_ These facts suggest the idea that beds comparable to the upper
part of the French Cenomanian, and, like it, containing many phos-
phatic nodules and casts of fossils, were originally deposited in the
Devon area, but were afterwards destroyed by the action of currents,
and nothing left of them except the hard phosphatic fossils, with
grains of quartz and glauconite, to be embedded as vemanié material
in the beds which overlie the zone of Ammonites Mantellt.

Having thus summarized the opinions which we have been led
to form from an examination of the rocks and their contents in the
West of England and France, we shall conclude by discussing
the view which i is generally held in the latter country regarding the
correlation of the several parts of the two series.

It is on the Cenomanian of Havre that we must concentrate our
attention, because when its relative age is settled that of the inland
departments will follow as a matter of course. No one now is
likely to recur to the view of Prof. Hébert that the Cenomanian
sands of the Sarthe are newer than the Craie de Rouen, and that
no representative of them exists in Normandy or England.

The view current at the present time among French geologists is
that the lower part of the Cenomanian of Havre, as defined by
M. Lennier and ourselves, corresponds with the upper part of our
Upper Greensand—with so much of it, in fact, as is included by
Dr. Barrois in his zone of Pecten asper. We cannot find, however,
that anyone has yet attempted to indicate how much of the Craie
glauconieuse is equivalent to the English Lower Chalk and how
much to the zone of P. asper.

It is true that Dr. Barrois has expressed his belief that his zone
of Ammonites laticlavius (our Chloritic Marl) in the East of France
corresponds with ‘le banc Rotomagien classique de Rouen,’* but
in answer to our enquiries he informs us that he has no personal
acquaintance with the Havre or Rouen sections; that the fossils
mentioned in his note were collected for him, and were said to come
from the ‘ Craie de Rouen’ ; that he had no assurance that they came
from Rouen itself; that some of them are preserved in whitish
phosphate and some in glauconitic material, and that they may be
‘un mélange.’ This being so, it is quite possible, as he admits, that
some of them were obtained on the coast, and may have come from
the very bed which we identify with the Chloritic Marl; in any
case, we feel sure that if Dr. Barrois had visited Havre after his

1 «Mém. sur le Terr. Crét. des Ardennes,’ Ann. Soe. ae Nord, vol. v. gure 5)
p. 359, 5. Lone

Vol. 52.] -—S« ‘A DELIMITATION OF THE CENOMANIAN. 175

prolonged study of the Cretaceous rocks of England he would have
arrived at the same conclusion as we have.

It is indeed much to be regretted that Dr. Barrois did not carry
out his intention of visiting Normandy, for there is no other
Frenchman who has so extensive a knowledge of the Upper Creta-
ceous series in England and France. It would appear that the
French have not yet indicated the place of the Craie de Rouen in
the coast-section ; that is to say, they have not divided this section
into a zone of Ammonites rotomagensis and a zone of A. Mantelli,
as at Vimoutiers. As regards its correlation with English sections,
the French view rests apparently on three points of similarity
between their ‘ Craie glauconieuse’ and our Upper Greensand, such
as would naturally strike any one who knew the English Chalk and
Greensand only from published descriptions ; these are :—

(1) The large amount of glauconite in the Cénomanien.

(2) The occurrence of frequent layers of chert.

(3) The presence of Pecten asper and other fossils common in the
‘ Warminster Greensand.’

We will take these points seriatim. (1) It is a mistake to
suppose that the material of the ‘ Craie glauconieuse ’ resembles that
of our Greensand. The very use of the word ‘Craie’ indicates the
difference, and is quite correct in the department of Seine Inférieure,
where the matrix does consist of fine chalky matter. Our Upper
Greensand, on the contrary, is a sand consisting of quartz and
glauconite, though it is sometimes cemented by calcite into a calca-
reous sandstone.

(2) The occurrence of layers and lumps of true chert does un-
doubtedly create a superficial resemblance between the two sets of
strata; but the researches of Dr. Hinde have so completely proved
the connexion between the formation of cherts and the existence of
siliceous sponges, that the mere occurrence of cherts can only be
taken as evidence of the conditions being locally favourable to the
growth of such sponges.

(3) The presence of Pecten asper and other fossils, which in
England are chiefly found in the Upper Greensand, is the sole argu-
ment that requires serious consideration. Let us first of all see
what it amounts to when admitted without any qualification.
Where does this special fauna exist in England? Certainly not in
the Chert Beds either of Wiltshire, Dorset, or the Isle of Wight,
which have everywhere a very limited fauna. What are usually
called ‘the fossils of the Warminster Greensand’ have mostly been
obtained from a bed of bright green sand (about 10 feet thick)
lying above the Chert Beds, and passing up into Chloritic Marl with
phosphate-nodules and Stauronema Carteri. It is only here, just
below the base of the Chalk, that the Chalk Marl cephalopoda make
their first appearance in England, and are associated with Pecten
asper and other fossils which very shortly disappeared from the
English part of the Cretaceous sea. It is quite a mistake to suppose
that this is a typical Upper Greensand fauna; it is only that of the

176 MESSRS. A. J. JUKES-BROWNE AND W. HILL: [May 1896,

very highest bed, so that if two thirds of the French Cenomanian
are to be correlated with the thin bed of Greensand near War-
minster on the strength of the similarity between the faunas, we
must imagine that this thin bed has expanded to a thickness of
80 feet or more in France, although the beds both above and below
have very greatly diminished in thickness.

Our lists, however, show that, of the fossils which may be
collected from these beds at Havre in a few days’ time, quite as
many occur in our Chalk Marl as in the Warminster Beds. We
suspect that the occurrence of Pecten asper has influenced the French
systematists more than any other element in the fauna; but our
experience in England has convinced us that P. asper is very
sporadic in its mode of occurrence, and required a very special kind
of environment.

We consider it very unsafe to trust to echinoderms or ground-
feeding molluscs in correlating at so great a distance apart forma-
tions of different lithological character, because the conditions of life
may also have been different inthe two areas. One condition alone,
namely, greater depth of water, might be sufficient to exclude from
the one formation species which found a suitable location in the
other area. This, we think, is the reason why Pecten asper and
many other of the Warminster molluscs and echinoderms do not
occur in the Chalk Marl, not because they had everywhere ceased to
exist, but simply because the water was too deep for them.

The case is quite different with the cephalopada, for they could
move freely from place to place, and were not directly dependent on
depth of water or on the nature of the sea-floor. They must there-
fore be much more trustworthy chronological guides ; and if we rely
upon their guidance in the present case, we find that they lead us to
the very conclusion which we regard as correct, for the cephalopoda
of the lower part of the Cenomanian of Havre are identical with
those of our Chloritic Marl and Chalk Marl, and they do not occur
in the Chert Beds of our Upper Greensand.

Let us now take another point of departure, and consider what
modifications are likely to present themselves in our Chalk Marl
when traced into shallower water and nearer to a line of coast. If
we examine the Chalk Marl of the Isle of Wight under the micro-
scope, we find that it actually isa Craie glauconieuse; it con-
sists essentially of minute grains of quartz and glauconite, and of
shell-fragments embedded in a fine chalky matrix. The material
of the corresponding part of the Cenomanian at Havre has less
of the chalky matrix, and a larger proportion of the inorganic
materials (quartz and glauconite).

There is, in fact, just the difference that one would expect to find
in a contemporaneous deposit accumulated rather nearer to the land,
and we have shown that this change gradually increases till the
chalky ingredient disappears entirely, and we reach shallow-water
sands and sandstones. Would it not be surprising if there were not
a corresponding change in the fauna? Is it likely that the same
assemblage of fossils would inhabit the littoral sandy floors, the

Vol. 52.] A DELIMITATION OF THE CENOMANIAN, 177

intermediate depths where glauconitic marls and sands were accu-
mulating, and the comparatively deep water of the Chalk Marl area?

Further, as the period was one of continued subsidence, and as
the formation of the Chalk Marl was preceded by that of glauconitic
sand in a shallower sea, what is more likely than that the creatures
which lived in the shallower sea should gradually migrate to other
tracts where the same conditions prevailed, as the area of the sea
grew larger, and the central portion of it grew deeper?

Expressed ina few words, our belief is that the ‘ Cénomanien’
of Havre and Rouen is simply a southern extension of our Lower
Chalk, formed in a somewhat shallower part of the sea, rather
nearer to a coast-line, and in a locality where conditions were more
favourable to the growth of siliceous sponges. Hence it consists
of a rather more sandy and glauconitic chalk, with a larger amount
of siliceous matter in the form of sponge-spicules and chert-nodules.

We would point out that English geologists have hitherto been
obliged to accept the idea of a ‘Cénomanien’ which could not be corre-
lated with any one or two divisions of the English Cretaceous series,
but was supposed to include a Pecten asper-zone which, in England
at any rate, had no definite base. Our enquiry relieves them from
the necessity of adopting so unsatisfactory a correlation, and sub-
stitutes a Cenomanian with a clearly-detined base both in England
and France.

As regards what has been termed ‘the zone of Pecten asper’ in
England, we think that some other fossil should be chosen as an
index of the zone, so as to avoid the confusion which has arisen
from the presence of Pecten asper at higher horizons in France.
Unfortunately cephalopoda are so rare in this zone that it is impos-
sible to select one of that class, and we think that it is best to
leave the matter for future consideration.

PLATE V.
Cenomanian Ammonites. For Explanation, see text, pp. 156, 157.

Discussion.

The Presrpent said that any attempt such as the Authors of the
present paper have made to correlate any part of the Cretaceous
beds of this country with those of the Continent must be hailed with
satisfaction by all students of geology ; and as the present Authors
have given especial attention to this subject, their views deserve the
most careful attention from geologists. He invited discussion on
the paper that they had just heard read, and asked Mr. Hill
whether the floating cephalopoda referred to by him included tetra-
branchiata, or were confined to dibranchiata.

Dr. W. F. Hume, in congratulating the Authors on the paper,
expressed himself in complete agreement with their conclusions, and
remarked on the extreme variation in thickness displayed by the
Cenomanian beds exposed in Beer Bay and Hooken Cliff respec-
tively. He also asked whether the Authors would consider the

178 A DELIMITATION OF THE CENOMANIAN. = [ May 1896,

Chloritic Marl to the westward as younger than the easterly
exposures of the same.

Mr. Srraman remarked that he was under a disadvantage in dis-
cussing the paper, through not having seen the Continental sections
referred to. Itseemed, however, to be clear that English geologists
were having reason to repent the introduction of Continental names
into their Cretaceous nomenclature. He himself had always hesi-
tated in using the term ‘ Cenomanian’ from a doubt as to its precise
application in this country. The correlation was most important,
for the principal break in our Secondary rocks occurs at the base
of the Upper Cretaceous group. He enquired if a ‘ Carstone’ and
yellow sand which intervened between the Gault and Kimmeridge
Clay at Cape La Heéve were not the same as the ferruginous grit which
forms the base of the Gault in Dorset and elsewhere. Phosphatic
nodules occur in the Chloritic Marl and sporadically through the
Upper Greensand, and seem to be foreign to the matrix in which
they are embedded. The glauconitic grains, too, seem unlikely to
have been formed in the water which distr ibuted the sands and
coarse grits. He asked the Authors whether they had any clue to
the deposits with which these materials had originally been associated.
In referring to Mr, Hill’s Continental investigations, he congratulated
him on a fine piece of work.

Dr. J. W. Gregory congratulated the Authors on the value of the
paper and the greater precision that they have given to a useful term.
The confusion in regard to the term ‘ Cenomanian’ is not so mucha
case of hasty use of a foreign name in England, as of unsatisfactory
original definition of the term abroad. He fully agreed with the
Authors that echinoids are rather a clue to conditions of formation
of a deposit than evidence as to its exact contemporaneity in age.

Mr. R. 8. Herries hoped that, as a result of this paper, geologists
would use the term ‘ Lower Chalk’ in place of ‘Cenomanian,’ at
any rate when speaking of the English beds here described.

Mr. W. Hitt, in. reply to the President, remarked that they
relied on the occurrence of tetrabranchiate cephalopoda to prove
the age of the beds, rather than on the fauna which must have existed
entirely on the sea-bottom. He thought that the Chloritic Marl of
the eastern sections was probably older than that more to the west-
ward. Beds 10,11, and 12 were certainly seen as far as Branscombe
Cliff. He believed that the phosphatized fossils, which Mr. Strahan
suggested were derived, were not necessarily so, but might be of the
same age as the bed containing them. There were but few phos-
phatized fossils in the Chloritic Marl of La Heéve; and the fact that
this marl contained small quartz-pebbles and much sand seemed to
him evidence of current-action. He was prepared to admit that
the Carstone-like bed seen in the cliffs at Cape La Héve might be
of Gault age, and, in conclusion, heartily thanked the Fellows of
the Society, on behalf of Mr. Jukes-Browne and himself, for their
cordial reception of the paper.

Vol. 52.] | SPEETON SERIES IN YORKSHIRE AND LINCOLNSHIRE. 179

8. On the Sprrton Series in YorxKsHtRE and Lincotnsuire. By
G. W. Lametuen, Esq., F.G.S., of H.M. Geological Survey.
(Read January 22nd, 1896.)

ConrTEnrs.

Page
Reere EOWA PET th 2a: 5 - chats. irae didn ceadeesueadesasabnceveecdedeeace- 179
II. Further Notes on the Speeton Section ...............sceceeees 180
III. Inland Extension of the Speeton Series in Yorkshire ...... 184

IV. The Speeton Series in Lincolnshire.
a. General Observations and Bibliography .................. 191
ore eee Feat ONAN oe eacln cocindan mene amactdind«;igenn eines sale 193
c. The Basement-bed of the Spilsby Sandstone............... 195
dae Bhe Sptlaby: Sandstone? *jec.tis.062.0-20-sdobs- oun vevsrevesoee 199
6. eche, Claxbys Lromstone ao. dpcik vise. ipstachcach sacs sada ose stees c 200
eee Mea Mane lM) ase cri al io EG Laue aciiohae bebelien aot 207
g. TheTealby Limestone (with the Upper Hee a Roach’) 209
[ep IE ATRE SUC) Ae ee retin. voctnse) saanodas-ancadseysccedsacdses den 211
WV yeratement of the Correlation -......27..-2 -sea---sa<secneosesenseue 212
VI. The Age of the Belemnites lateralis Beds .............scseeeeeees 213
Mae Conclapline: SumiMary 2-15-2802 cececs ln amoodeh Jstacdestesescnus 217
Sketch-map of the Yorkshire and Lincolnshire Wolds ...... 187
OG OMI tate cals no's iar asian sk skea sa noip eal spinmansleny ns 184, 192, 212

I. Iyrropvuction.

In describing the clays which underlie the Chalk at Speeton on the
Yorkshire coast in a paper communicated to this Society in 1889," I
attempted to show the necessity for a fresh classification of these
deposits. Further investigation of this section has fully confirmed
the views then advanced. It has also indicated the desirability of
a corresponding revision of the inland exposures of the rocks of the
same age in Yorkshire and Lincolnshire, since it is only by means.
of the knowledge of the full sequence to be acquired on the coast-
section that the true relationship of the limited and isolated ex-
_ posures of the interior can be unravelled.

Using such opportunities as have at intervals occurred, I have
therefore more or less closely examined the base of the Chalk
escarpment throughout its whole length in Yorkshire and Lincoln-.
shire, and desire in this paper to put on record the result of my
investigation. It will be shown that the divisions proposed for the
Speeton section are readily applicable to the inland exposures, and
indeed afford the most convenient and natural means of pale-
ontological classification, albeit some modification of the systems
usually applied is thereby required.

It may be well at once to state that, while my chief aim will be
to establish the correlation of the deposits by means of their pale-
ontology, no attempt will, for the present, be made to carry the
palzontological research further than is necessary for this purpose.
Hence the fossils dealt with herein will only partially represent

* *On the Subdivisions of the Speeton Clay,’ Quart. Journ. Geol. Soc.
yol. xlv. pp. 575-618.

Q.J.G.S. No. 206. 0

180 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 18096,

the fauna of the various deposits. With the material already
collected it would indeed have been possible to present much
ampler lists. But the mischief done by the publication of swollen
catalogues of hasty determinations, not in these deposits alone, but
throughout the whole range of the Secondary rocks, has been so
great, and the precise recognition of many of the forms in the
present state of their nomenclature is so difficult, that I have
thought it advisable to restrict myself as far as possible to the use
of those few species which have been adequately described and
figured rather than risk adding to the existing confusion.

That the fauna of these rocks has been hitherto much neglected
by British paleontologists is no doubt mainly due to the fact that,
so far as the British Islands are concerned, it is comparatively
restricted both in its occurrence and its interest, the fossils of
these marine deposits affording no ready points for comparison with
those of the equivalent freshwater strata of the south of England.
Over large areas of the continent of Europe, however, as was so
clearly shown 25 years ago by Prof. Judd,’ the conditions of deposit
are more directly comparable, and there is a close relationship in
the fauna. Recently Prof. A. Pavlow” has made a very careful
study of the cephalopoda of these rocks with this relationship in
view, and his monograph for this branch of the fauna affords a
secure basis from which to discuss many questions of stratigraphy
and correlation. But not until the rest of the fauna has been
taken in hand, and in like manner studied and compared with that
of the Continental equivalents of these deposits, will it be possible
to compile satisfactory lists of the fossils, or to consider to full
advantage the broader aspects of the subject.

Il. Furtuer Norss on THE SPEETON SECTION.

In my former paper I proposed to divide the clays of the Speeton
section into zones by means of the belemnites, which are by far the
most abundant and the most characteristic fossils contained in the
deposit.* Prof. Pavlow has since shown that each type of belemnite
selected for this purpose may be considered palzontologically as a
group of allied forms presenting variations of specific value. These
variations will no doubt in some cases enable us to trace out minor
zones.

1 « Additional Observations on the Neocomian Strata of Yorkshire and
Lincolnshire, etc., Quart. Journ. Geol. Soe. vol. xxvi. (1870) pp. 326-348.

2 “Argiles de Speeton et leurs Equivalents,’ Bull. Soc. Imp. d. Naturalistes
de Moscou, n. s. vol. v. pp. 181 & 455 (1891-92). (Also published separately,
Moscow, 1892.)

3 At that time some objection was raised to my selection of the belemnites
as the zonal fossils; but, as I then stated, it was quite evident that no other
fossils would serve the purpose so well, and I am pleased to find that this
statement has been fully borne out and justified by further investigations. As
Pavlow has shown, the study of the belemnite-fauna of the epoch is prolific in
results throughout Europe. Prof. Dames, in a recent paper, ‘ Ueber die
Gliederung der Flotzformationen Helgolands,’ states for that island ‘hier
wie dort sind die Belemniten die leitenden Fossilien,’ Sitzungsber. k. preuss.

Akad. Wissensch. Berlin, vol. 1. (1898) p. 1031.

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 181

Thus Belemnites pistillirostris and B. cristatus are together more
restricted in their range than B. jaculum, to which they are closely
allied; while B. Jasikowi and B. obtusirostris similarly occupy a
portion only of the zone of B. brunsvicensis.

As several of the forms, however, seem to occur indiscriminately
‘throughout the realm of the allied species, I think that for strati-
graphical employment, as distinct from their more strictly pale-
-ontological study, it will be found serviceable to retain for our
present purpose the broader system of nomenclature. It must
‘therefore be understood that in the stratigraphical notes in the
following pages the specific names of the zonal belemnites, and to
-a less extent of the zonal ammonites also, will be freely used in
this broader sense, embracing all the closely-allied variations.

Since 1889 I have several times had opportunities for examining
exposures of the strata on the foreshore at Speeton, and have been
enabled thereby to collect much new paleontological material, and
to fix the horizon of a few forms whose exact position had been
doubtful. These results, as regards the cephalopoda, are sum-
‘marized in the Table facing p. 184, where the species as determined
‘by Prof. Pavlow are arranged according to their stratigraphical
‘position.

[On revisiting Speeton while this paper was in the press I had the
good fortune to find in the uppermost part of the section, of which
our knowledge is still incomplete, among the recent slips under the
Chalk escarpment 450 yards south of Speeton Gap, a small strip of
‘brown marly clay, 2 or 3 feet thick, which contained belemnites of
a type that I had not hitherto seen at Speeton. In structure, size, and
outline this form shows close affinities to Belemnites jaculum, but
differs markedly from that species in the character of the alveolar
extremity: most of the specimens possess a slight lateral groove
in the subalveolar region. It seems very probable that this may
be the form recorded from Heligoland by Prof. Dames (op. jam
it.) as B. fusiformis, Voltz, which in that island occupies a zone
between the beds with B. minimus and those with B. brunsui-
Lensis.

I could find no other fossils along with this belemnite, and the
band which contained it was bounded on all sides by slips; but
below the brown clay was a mass of black pyritous clay with
Ammonites Deshayesvi, and above it dull black clay without fossils
-such as I have elsewhere seen to occur beneath the marls (A) with
B. minamus, and there is much likelihood that the slips have preserved
the true sequence of the beds.—April 22nd, 1896. ]

The reiterated * contention of the Rey. J. F. Blake® that ‘ Port-
landian’ beds may after all exist, as supposed by Prof. Judd,

1 ‘Annals of British Geology for 1892’ (London, 1893), Introductory
Review, p. xviii.
° *Geology of the Country between Redcar and Bridlington,’ Proc. Geol.
Assoc. vol. xii. (1891) p. 115.
02

182 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

between the lower Coprolite Bed (EK) and the Bituminous Shales (F)
of my published section, though it has already been once answered,’
must here be referred to. The contention is based on a misap-
prehension of the valuable section published by Leckenby in 1859,”
for it is beyond doubt that the Bituminous Shales (F of my
former paper) are the same strata as the ‘ Beds Nos. 4 and 5’ of
Leckenby’s section which Blake suggests I may not yet have seen.

These shales have been frequently exposed at Speeton both before
and since the publication of my account of the section, and I have
carefully examined them to a greater depth than my measure-
ments indicated, since (as stated in my previous paper) the folds:
into which they are locally thrown, and their position near low-
water mark on the foreshore, render detailed work on their lower
portion very difficult.

The only beds described by Leckenby that I have not yet had
an opportunity of examining are those still lower strata to which he
applies the numbers 1, 2, and 3, and assigns a thickness of 30 to 40°
feet. The fauna is apparently rather better preserved in these beds
than in the compressed shales above, and is of undoubted Kimeridgian:
age, including Ammonites (Perisphinctes) byplea; A. (Hoplites) eudoxus
=A. evalidus, Bean MS.; a form near A. alternans, labelled A.
Kapfii, Opp.,in some collections ; and Belemnites Troslayanus, d’Orb..

Specimens from this horizon occur in all the old collections pre-
served in our public museums, butthe only examples that I have myself
obtained have been from nodules washed up on the beach. Mr. R.
S. Herries, however, has. been more fortunate, having some years |
ago found an exposure of the strata on the foreshore north of
Speeton from which he was able to collect all the above-mentioned
species, and I have to thank him for his kindness in so readily
placing these, with other specimens from his extensive collection, at
my disposal. The same horizon seems, as will presently be shown,
formerly to have been exposed in one of the clay-pits at Knapton,.
14 miles inland.

Our knowledge of the lowermost portion of the Speeton section,
below the top of the Upper Kimeridge Shales, must therefore still
rest on Leckenby’s meagre but probably quite accurate description..
I have before pointed out that the so-called ‘ Middle Kimeridge ’
and ‘Lower Kimeridge’ mentioned by Prof. Judd* and others*
as occurring in Filey Bay seem, as now admitted by Blake,’ to
consist entirely of glacially-transported masses of shale, chiefly of
Lower Lias age, such as characterize the drift-deposits of this part
of the coast.

‘A well-boring sunk by the Filey Waterworks Company in a field
adjoining the railway-station at Filey, after passing through 190 feet

* *Argiles de Speeton,’ op. cit. 1° partie, p. 210; sep. cop. p. 30.

2 ‘Geologist,’ vol. ii. p. 9.

> “On the Speeton Clay,’ Quart. Journ. Geol. Soc. vol. ae Ae p. 240.

4 J. F. Blake, Quart. Journ. Geol. Soc. vol. xxxi. (1875) p.

° «Excursion to the Hast Coast of Yorkshire,’ Proc. Meck Assoc. vol. xii.
(1891) p. 213.

Wolk: 52:] IN YORKSHIRE AND LINCOLNSHIRE. 183

of drift,! further penetrated pale-blue sandy clay or shale for
754 feet before reaching the water-bearing Coralline Oolite. This
shale evidently represents the lowest Kimeridgian beds; the only
fossil that I was able to obtain from it was an indeterminable
fragment of a small slender belemnite, distinct from any of the
Speeton species known to me.

In my former paper I described the strikingly sudden change of
fauna which takes place at the top of the zone of Belemnites lateralis.
Immediately below this horizon the prevalent ammonites are the
deep-whorled, round-backed forms of the genus Olcostephanus and its
allies, and the belemnites all belong to the short thick lateralis-
group, while immediately above it the clays abound in the flat-
whorled, square-backed ammonites of the genus Hoplites and the
slender hastate belemnites of the jyaculum-type. So complete is this
change that I was in doubt when previously describing it whether
the apparent mingling of the forms at the junction of the zones
in the ‘Compound-Nodule Band’ (D1) really indicated contem-
poraneity, or whether through lack of sedimentation the dead
remains of the older fauna had lain uncovered on the sea-floor long
enough to become embedded in the same layer with the first relics
of the new species.” I have, however, since found two specimens
of the lateralis-type of Belemnites (B. subquadratus, Roem.) dis-
tinctly within the zone of B. jaculum, the first in the clay imme-
diately overlying D1, and the second in the clay 18 inches above
that band, which proves that the older type was not quite extinct
on the appearance of the newer, though very nearly so.

The researches of Prof. Pavlow on the Speeton fossils have thrown
new light on the change at this horizon. He has been able to
demonstrate that the incoming fauna was one which had been de-
veloped and had prevailed in southern seas, while the displaced fauna
was markedly northern in its origin and range.* The southern
fauna remains almost pure throughout the ‘ noricus-beds’ (C11 to
C7), but above that zone the Olcostephani reappear in a group of
species (centring around Ammonites speetonensis) which, while dis-
tinctly recalling the Olcostephanz of the upper part of the lateralis-zone
{D1 to D3), are yet so completely modified as to be in every case
specifically different. These replace the Hoplites-type of ammonites,
and though the hastate belemnites (Belemnites jaculum and allies)
persist much longer, they also eventually disappear, and the field
is reoccupied by types (B. brunsvicensis) which have probably been
derived from ancestors pertaining to the lateralis-group.

The line of research thus indicated is still being pursued, and
promises to be rich in results bearing on the extent and character

1 See Mem. Geol. Surv. ‘ Jurassic Rocks of Great Britain: Pt. I. Yorkshire,’
by C. F. Strangways, p. 375.

? ‘Subdivisions of the Speeton Clay,’ Quart. Journ. Geol. Soc. vol. xlv.
(1889) p. 589.

° ‘Argiles de Speeton,’ pp. 93, 188 et segg. (sep. cop.) and ‘On the Marine
Beds closing the Jurassic and opening the Cretaceous, with the History of their
Fauna,’ by A. Paylow, in Bull. Geol. Soc. America, vol. iii. (1892) p. 61.

184 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [ May 1896,

of the life-provinces of the period and the climatic conditions and
changes.

The list; of the cephalopoda of Speeton as determined by Pavlow
has not hitherto been printed in this country, and is therefore
given in the Table facing this page. One or two species whose exact
position in the series has been ascertained since 1892 are herein
for the first time relegated to their proper zones.

Here I beg leave to thank Prof. A. Pavlow and Messrs, HE. T..
Newton, F.R.S., and G. C. Crick for their invaluable aid and advice
in regard to the paleontology, and Mr. J. W. Stather, for his.
kindly assistance in various ways in the field, and for the loan of
his specimens.

LIL. Intanp Extension oF THE SpEETON SERIES IN YORKSHIRE.

The available evidence respecting the inland prolongation of the-
Speeton clays is very restricted and unsatisfactory.

Prof. Judd? mentions their reappearance about a mile dis—
tant from the coast in a stream-course near Reighton; but this.
exposure seems to have been at all times very obscure, and it is-
now no longer recognizable.

Iam informed that clay like that of Speeton was reached in a
well sunk a few years ago near Hunmanby Station, 2 miles from
the coast; but I could not learn that any fossils were obtained, and
there is consequently no means of determining the horizon.

Farther westward the solid rocks at the foot of the steep escarp-
ment of the Chalk are completely hidden by the drift and alluvium
of the Vale of Pickering for about 12 miles; but after this in-
terval the steady rise of the base of the Chalk brings the under-
lying clays above the valley-flat ; and there were at one time some
small pits in these clays, near the foot of the slope, in the vicinity
of the village of Knapton, from which many fossils were obtained..
The excavations, however, have been discontinued for half a cen-
tury, and the sections are now entirely obliterated. A few fossils
obtained many years ago from these old pits have been preserved
in our public museums, and these furnish certain valuable though.
scanty indications with regard to the horizon of the deposits.
Prof. Judd has supposed? that only the lowest members of the
Speeton Series are present in this area, and that the ‘ Middle’ and:
‘Upper’ of his divisions of the coast-section have been cut out by
the unconformable overlap of the Chalk. But I have elsewhere
shown * that while the fossils above mentioned indicate the almost.

1 « Additional Observations on the Neocomian Strata of Yorkshire and:
Lincolnshire,’ Quart. Journ. Geol. Soc. vol. xxvi. (1870) p. 327. The clay in
question is referred in this paper to the ‘Zone of Ammonites speetonensis’ ; butas-
Belemnites lateralis is recorded, which species does not occur in the speetonensis-
beds, while there is no mention of the occurrence of the characteristic Belem-
mites jaculum, I think that the correlation can scarcely be regarded as-
established.

2 Ibid. p. 329.

° «The Neocomian Clay at Knapton,’ The Naturalist (Leeds), Nov. 1890.

Quart. Journ. Geol. Soc. Vol. LII. [To face p. 184.

TABLE OF THE CEPHALOPODA OF THE SpEETON SERIES.

Zone and Bed. AMMONITES. BELEMNITES.

A.

Belemnites minimus, List.
Passage-marls a. | a Hoplites interruptus? Brug.

attenuatus, Sow.
— ultimus, d’Orb.

B.
Zone of Bel.
brunsvicensis.

Bel. brunsvicensis, Stromb. (pl. vii. (iv.) figs. 9, 10).
—— speetonensis, Pavl. (pl. vii. (iv.) figs. 18, 14).
—— absolutiformis, Pavl. (pl. vii. (iv.) figs. 11, 12).
Jasikowi, Lahus. (pl. vii. (iv.) fig. 8).
obtusirostris, Pavl. (pl. vii. (iv.) fig. 7).

Hoplites Deshayesii, Leym.
Amaltheus bicurvatus, Mich.

Ci to upper Olcostephanus (Simbirskites) Decheni, Roem. (pl. xviii. (xi.) figs. 4, 5, 6).
part of C6. b ( ) wnbonatus, Lahus. (pl. xviii. (xi.) fig. 8).
— = discofalcatus, Lahus. (pl. xviii. (xi.) fig. 2).
——) speetonensis, Young & Bird (pl. xviii. (xi.) fig. 7).
—— (—) progrediens, Lahus. (pl. xviii. (xi.) fig. 15),
— ( ) concinnus, Phill. (pl. xviii. (xi.) fig. 16).
b —— ( ) cf. Carteroni, d’Orb.
(Holcodiscus) rotula, Sow. (see below).
b Crioceras cf. Matheroni, VOrb. (pl. xviii. (xi.) fig. 10).

——

Belemnites jaculwm, Phill. (pl. vii. (iv.) figs. 2, 3, 4).
Jasikowi, Lahus. (see above).

pistillirostris, Pavl.

cristatus, Pavl. (pl. vii. (iv.) fig. 5).

eP

Lower part
of C6 and
C7.

Olcost. (Simbirskites) subinversus, M. Pavl. (pl. xviii. (xi.) figs. 12, 18).
( ) inversus, M. Pavl. (pl. xviii. (xi.) fig. 14).
—— (——_) Payeri, Toula (pl. xviii, (xi.) fig. 1).

) versicolor? Trautsch.

(Holcodiscus) rotula, Sow. (see below).

b Crioceras capricornu, Roem. (pl. xviii. (xi.) fig. 9).

rere

C8to Cll. Hoplites regalis (Bean.), Pav. (pl. xvii. (x.) figs. 1, 2).
amblygonius, Neum. & Uhl. (pl. xvii. (x.) fig. 6).
— ouygonius, Neum. & Uhl. (pl. xvii. (x.) figs. 4, 5).
— Roubaudi (munitus), VOrb. (pl. xvii. (x.) fig. 8).
— cf. Huthymi, Pict. (pl. xvii. (x.) fig. 7).
heteroptychus, Pavl. (pl. xviii. (xi.) fig. 22).

— WMortelleti, Pict. & Lor.

s
Ss
s
S
38
=)
2)
D
~
‘2
S$
S
~~
)
ae
Se
°
o
=I
(e)
N

Belemnites subquadratus (rare), d’Orb. (pl. vii.
(iv.) fig. 1).

bP
b?

Quart. Journ. Geol. Soc. Vol. LII.

TABLE OF THE CEPHALOPODA OF THE SpHpron Swrres.

[To face p. 184.

Zone and Bed.

AMMONITES.

BELEMNITES,

Passage-marls a.

a Hoplites interruptus? Brug.

Belemnites minimus, List.
attenuatus, Sow.
—— ultimus, d’ Orb,

B.
Zone of Bel.
brunsvicensis.

Hoplites Deshayesii, Leym.
Amaltheus bicurvatus, Mich.

Bel. brunsvicensis, Stromb. (pl. vii. (iv.) figs. 9, 10).
speetonensis, Pavl. (pl. vii. (iv.) figs. 13, 14).
—— absolutiformis, Pay), (pl. vil. (iv.) figs. 11, 12).
Jasikowi, Lahus. (pl. v: ) 8).
obtusirostris, Pav). (pl. vii. (iv.) fig. 7).

C1 to upper
part of C6.
8
Lower part 8
of C6 and -&
C7. 8
aS
=
8
is
C8toCll. yw
°
2
q
J}
N

Olcostephanus (Simbirskites) Decheni, Roem.
6 — ( ) wnbonatus, Lahus. (pl. xviii. (xi.)

(pl. xviii. (xi.) figs. 4, 5, 6).
tig. 8).
— = discofalcatus, Lahus. (pl. xviii. (xi

ig. 2).
—) speetonensis, Young & Bird (pl. x (xi.) fig. 7).
—— (—) progrediens, Lahus. (pl. xviii. (xi.) fig. 15),
— (——) concinnus, Phill. (pl. xviii. (xi.) fig. 16).
6— (. ) cf. Carteroni, V@Orb.
—— (Holcodiscus) rotula, Sow. (see below).
6 Crioceras cf. Matheroni, d’Orb. (pl. xviii. (xi.) fig. 10).

Olcost. (Simbirskites) subinversus, M. Pavl. (pl. xviii. (xi.) figs. 12, 13).
inversus, M. Payl. (pl. xviii. (xi.) fig. 14).
Payeri, Toula (pl. xviii. (xi.) fig. 1).
) versicolor ? Trautsch.
— (Holcodiscus) rotula, Sow. (see below).
b Crioceras capricornu, Roem. (pl. xviii. (xi.) fig. 9).

eae ees

=

Hoplites regalis (Bean.), Pav. (pl. xvii. (x.) figs. 1, 2).
amblygonius, Neum. & Uhl. (pl. xvii. (x.) fig. 6).
oxygonius, Neum. & Uhl. (pl. xvii figs. 4,5).
— Roubaudi Coie) d’Orb. (pl. xvii. (x.) fig. 8).
— ct. Euthymi, Pict. (pl. xvii. (x.) fig. 7).
— heteroptychus, Payl. (pl. xviii. (xi.) fig. 22).
Mortelleti, Pict. & Lor.
Olcostephanus (Astieria) Astieri, @ Orb. (pl. xvii. (x.) fig. 15).
sulcosus, Pavl. (pl. xviii. (xi.) fig. 18).
b ? —— (—) Atherstoni, Sharpe (pl. xvii. (x.) fig. 14).
6 ? —— spitiensis, Blanford.

— (Holcodiscus) rotula, Sow. (pl. xvii. (x.) fig. 11).

b Acanthoceras ? peltoceroides, Pavl. (pl. xviii. (xi.) fig. 20).

6 ? Desmoceras cf. cassidoides, Uhl. (pl. xviii: (xi.) fig. 19).

be
bP

Upper part
of

Hoplites vegalis (Bean), Pavl. (see above).
amblygonius, Neum. & Uhl. (see above),

oe? —— Jasikowi, Lahus. (see above).

Belemnites jaculum, Phill. (pl. vii. (iy.) figs. 2, 3, 4).

—— pistillirostris, Pavl,
— cristatus, Pavl, (pl. vii. (iv.) fig. 5).

Belemnites subquadratus (rare), d’Orb. (pl. vii.
(iv.) fig. 1).

— hystrix, Phill. (pl. xvii. (x.) fig. 10).

—— Roubaudi, VOrb. (see above).

Olcostephanus (Holcodiscus) rotula, Sow. (see above),

— (Polyptychites) bidichotomus, Leym. (pl. xvi. (ix.) figs. 2, 3, 4).

Olcost. (Polyptychites) Keyserlingi, Neum. & Uhl. (pl. xvi. (ix.) fig. 1).
— (——) gravesiformis, Pavl. (pl. sii. (vi.) fig. 7).
— (——) Lamplughi, Pavl. (pl. xiv. (vii.) fig. 1, & xv. fig. 1).
—— (——) ramuticosta, Pavl. toi. xy. (viii.) fig. 6).
—— ax Beani, Payl. (pl. xy. (viii.) fig. 7).
6 2? — =a triplodiptychus, Pavl. (pl. xy. (viii.) fig. 4).
b 2? —— (——) polyptychus, Keys. (pl. xv. (viil.) fig. 2).

e Olcostephanus (Craspedites/) fragilis, Trautsch. (pl. xiii. (vi.) fig. 4).
e—— (——) cf. subditus, Trautsch. (Lincolnshire specimen figured, pl. xiii.
e Oxynoticeras cf. catenulatum, Fisch. {(vi.) fig. 5).

&
3
$
s
Lower part «
of D1, D2, $
and D 3. §
we
3
Q
=
°
g
D4 8
to
Ds.
E,

“Coprolite-Bed”

Olcostephanus (Virgatites) cf. Panderi, d’Orb (pl. v. (ii.) fig.5).

— (eae cf. seythicus, Michal. (pl. v. (ii.) fig. 7).
—) et. Dehernischowi, Michal. (pl. a fig. 6).
—— (—) cf. dorsoplanus, Michal. (pl. v. (ii.) fig. 4).

Belemnites lateralis, Phill. (pl. vi. (iii.) fig. 8).
— russiensis, V’Orb. (pl. vi. (iii.) fig. 7).
—— subquadratus, VOrb. (pl. vi. (iii.) fig. 5).
—— explanatoides, Pav). (pl. vi. (iii.) fig. 1).
d— explanatus? Phill. (pl. vi. (iii.) fig. 2).

Belemnites, cf. absolutus, Fisch. (pl. v. (1i.) fig. 3).
—— magnificus, a Orb, (see below).

s ses

imeridge
Clay.

Upper portion.

Lower portion.

Perisphinctes lacertosus, Dum. & Font. (fig. at p.111, “Argiles de Speeton i
Olcostephanus (Virgatites) ct. miatchkoviensis, Michal. (pl. iy. (i.) fig. 6

Belemnites magnificus, d’Orb. (pl. v. (ii.) fig. 1).
— porrectus, Phill. (pl. iv. (i.) fig. 3).
obeliscoides, Pavl. (pl. iv. (1.) fig. 2).

—— Puzosi, d’Orb. (pl. iv. (i.) fig. 1).

Hoplites pseudomutabilis, Loriol (pl. iv. (i.) fig. 7).
See ncaa ENING Ba a) EO
—— eudoxus, Orb,

b Belemnites Troslayanus, d’ Orb. (pl. viii. (v.) fig. 4),

agrees well in
Gault forn
at With

b. Thi

The reference-letters and figures in the first column refer to the beds
of the Speeton Clay as numbered in the vertical sections of my former
pees (Quart. Journ. Geol. Soc. vol. xlv. 1889, facing p. 618).

‘The reference in parentheses after the name of the species is given
when the species has been figured by Pavlow in ‘ Argiles de Speeton.’
_ 4 This topmost part of the section was not included by Prof. Pavlow
in his table (‘Argiles de Speeton,’ p. 157).
condition of a compressed cast, but it is evidently a species different from
any known to exist in the underlying Zone B, and, so far as can be seen,

Notes on the above Table.

tained.

The ammonite is in the

in a single

eral characters with Ammonites i: , a Lower e. I have

324),
Riesing
ieee

mination.

of ammonites from this horizon at Speeton, and, as

(op. cit. p. 118), such fossils do not lend

Tn the Spilsb; » of
vedites

Lincolnshire, only in Zone B, but not in Zone C, and the fossil is placed
in the latter zone on the authority of Prof. Pavlow. i
d. Tt appears to me doubtful whether this determination can be sus-
he specimen in question certainly agrees very closely with
Phillips's species explanatus, but it may be no more than an extreme
variation of the explanatoides-type of Belemnites lateralis, If a
number of specimens of this type be compared with a similar number of
the Kimeridgian explanatus, the difference becomes inore apparent than
ecimen.

able to obtain only small and yery perateble specimens

large

ani as f. Parone ie
aselves re z
hi readily to det

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 185

certain presence of the upper portion of the Speeton Series in the pits,
there is no proof of the existence of the lower zones.
The fossils in question are as follows :—

In the Natural History Museum, South Kensington (in the Bean
Collection).

Ammonites (Hoplites) Deshayesii, Leym. One of the specimens bears a label
with the MS. name 4. knaptonensis, Bean.*

Ammonites planus, Phill., probably the young form of A. (Amaltheus) bicur-
vatus, Mich. I have recently found the same form at Speeton similarly asso-
ciated with Hoplites Deshayesit.

? Ammonites (Hoplites) regalis, Pavl. It is doubtful whether this is really a
Knapton species. Two small unlabelled specimens are contained in a tray with
other fossils marked ‘ Knapton, but in appearance they closely resemble Speeton
specimens and differ from the Knapton fossils.

In the Woodwardian Museum at Cambridge.

Terebratulina Martiniana,? dOrb.; labelled Terebratulina striata.

In the Museum of the Scarborough Philosophical Society.
Pholadomya (Martini, Forbes) ? ; in a rather crushed condition.

To these we may also add the following species recorded by Prot. J. Phillips
in his ‘ Geology of the Yorkshire Coast’ (8rd ed. p. 242) :—

Hamites maximus (mentioned in Ist edition only),
Waldheimia faba, d’Orb.
Rhynchonella lineolata, Phill.

Some further evidence on the subject is afforded by the descrip-
tion of one of the Knapton pits given in 1822 by Young and Bird
in their ‘ Geological Survey of the Yorkshire Coast,’ which reads as
follows (2nd ed. p. 62) :—

‘In one of the clay-pits at Knapton we see the junction of the
shale with the red and grey chalk. The clay, where it joins the
chalk, is soft and plastic; and this, also, is the case with the lower
part of the chalk. The two substances are partly blended together ;
the soft chalk, which occurs here of both colours, approaching to
the state of red or grey clay ; while the clay that is next the chalk
is somewhat impregnated with calcareous matter, and is almost
divested of its schistose quality. The same facts are observed in
the specimens from the Staxton boring, and at the junction of the
chalk and shale in the lower part of the Speeton cliffs.’

This description implies a gradual passage of the Red Chalk into
the underlying clay, and is quite opposed to Prof. Judd’s view that
there is an unconformable overlap of the base of the Chalk at this

* From a reference to this species in Young and Bird’s ‘ Geological Survey of
the Yorkshire Coast,’ I should, however, judge that the name was originally
applied by Bean to the ammonite next on the list, namely, 4. planus, Phill.,
since the fossil is classed with the Nautili, and described as follows:—‘ A minute
flat shell, remarkably smooth, with a small umbilicus and a slight keel, occurs
in the upper shale. It resembles some of the ammonite family, and Mr. Bean
has named it A. knaptonensis’ (2nd ed. 1828, p. 272).

2 I am indebted to Mr. J. F. Walker, M.A., for this determination.

186 sPEETON SERIES IN YORKSHIRE AND LINCOLNSHIRE. [May 1896.

point. The marly passage-beds seem to be exactly similar to those
which, as Young and Bird remark, exist at the same horizon at
Speeton.’ The section is now entirely hidden, but near a spring
which issues from the base of the Red Chalk at the eastern side
of Knapton Plantation, less than 200 yards distant from the largest
of the old pits, I have found several fragments of belemnites, trampled
out of the clayey subsoil by sheep, and these appear all to belong
to the stout variety of B. minimus (perhaps=B. subfusiformis of
some authors), which abounds in the passage-mar]s at Speeton.

A well-boring at East Heslerton, 2 miles farther east, according
to the account given in the Geological Survey Memoir,’ also passed
through ‘red clay’ immediately below the Chalk, probably denoting
the presence of similar passage-marls.

As will presently be shown, the evidence of the western ‘wold-
scarp, both in Yorkshire and in Lincolnshire, is likewise in agree-
ment with this interpretation of the Knapton section.*

In the more westerly of the Knapton pits, on the slope almost
due south of Knapton Hall, the clay seems to have belonged to an
horizon altogether lower and not, strictly speaking, referable to
any part of the true Speeton Series, a portion of the Kimeridge
Clay some little depth below the top being, I think, here
represented. I found in one of these old pits a large limestone
concretion containing fossils, evidently similar to the septaria
referred to by Prof. Judd,* which had presumably been rejected
when the clay was excavated. This nodule yielded several identi-
fiable fragments of ammonites, which I have every confidence in
referring to the well-known Kimeridge species Ammonites (Hoplites)
eucdoxus, d’Orb., a form known, as mentioned on a previous page,
to the old collectors as A, evalidus,’ Bean MS. Phillips also
records Rhynchonella inconstans, Sow., from the ‘ Kimeridge Clay,
Knapton’ (‘ Geology of Yorkshire,’ 3rd ed. 1875, p. 243).

There is, therefore, much probability that we have in this clay
the equivalent of ‘Bed No. 3’ of Leckenby’s Speeton section, and
that the horizon is well below the summit of the Kimeridgian strata.

Owing to the slipped state of the escarpment on these slopes, it is
scarcely possible to make any safe estimate of the thickness of the
clay between this pit and the base of the Chalk, but it cannot be
great; so that whatever higher beds of the Kimeridge Clay may

1 “On the Subdivisions of the Speeton Clay,’ Quart. Journ. Geol. Soe.
vol. xlv. (1889) p. 602.

2 Mem. Geol. Surv. 1880, ‘Oolitic and Cretaceous Rocks south of Scar-
borough,’ p. 26.

3 In Heligoland a similar sequence obtains (see Dames, ‘ Ueber die Gliederung
der Flotzformationen Helgolands, Sitzungsber. k. preuss. Akad.f Wissensch.
Berlin, vol. 1. 1893, p. 1032), and here also no evidence seems to be forthcoming
for the existence of the lowest beds of the Speeton series.

4 Quart. Journ. Geol. Soe. vol. xxvi. (1870) p. 328.

5 Prof. Judd mentions the occurrence of this ammonite at Knapton, but
considers it (in his later work) as equivalent to A. fascicularis, d’Orb., a
Lower Cretaceous species, from which, however, it differs in many respects (see

a remark as to this in my former paper, Quart. Journ. Geol. Soe. vol. xlv.
1889, p. 613).

Bay
SKETCH-MAP OF THE

YORKSHIRE AND LINCOLNSHIRE
WOLDS,
(based on the map infl.B.Woodwards
‘Geology of England & Wales’)
Scalegi inch—= about 18 miles.

Railways... ease

{Skegness

NOTE: The outcrop of the SPEETON SERIES is
roughly indicated by the horizontal shading.

JLypo. Etching Co.St.

188 MR. G, W. LAMPLUGH ON THE SPHETON SERIES {May 1896,.

exist, along with all that remains of the Speeton Series, are here
contained within a very narrow compass. Somewhere in this
vicinity the final thinning-out of the latter must occur, as we find:
that in going westward from Knapton all trace of the Speeton
Series is almost immediately lost, and the Red Chalk, also attenuated,.
appears to rest directly on the Kimeridge Clay.

From the absence for several miles of any further section reveal-
ing the character of the clays immediately beneath the Chalk, it is.
rather unsafe to assert positively that no clay except the Kimeridge-
exists in this position, but no proof to the contrary is forth-
coming. Four miles west of Knapton the hitherto westerly trend
of the Wold escarpment is rather suddenly changed for a southerly
or south-south-easterly direction, which persists up to, and beyond,
the Humber, to the end of the Wolds in Lincolnshire. In the
neighbourhood of the bend the character of the base of the Red
Chalk undergoes an important alteration, by which, instead of pre-
senting a gradual passage into the clays, it assumes a pebbly or
conglomeratic aspect, and preserves this character in a greater or
less degree throughout the whole extent of its course along the
western margin of the Yorkshire and Lincolnshire Wolds. Some
information regarding the underlying clays may be gleaned from the
old spoil-heaps of the Burdale tunnel on the Malton and Driffield
railway. ‘The northern end of this tunnel has been excavated for
‘some distance in the clays, and has cut their junction with the Chalk. ©
Such fossils as I have been able to recognize among the débris are:
all Kimeridgian forms, and none proper to the Speeton Series have
been found. Fragments of belemnites are rather abundant, appa-
rently referable mostly to the Kimeridgian species B. eaplanatus,
Phill., with perhaps also B. Troslayanus; and an imperfect specimen
of the former species was obtained from the clay in the banks of the
little stream at Wharram Percy. It seems clear that in this region
elevation and erosion were going on contemporaneously with the
steady deposition of muddy sediment in the submerged area to the
eastward, and that these conditions continued to prevail until the
setting-in of that slow and persistent depression which brought
about the accumulation of the great Chalk-formation.

Along the western margin of the Yorkshire Wolds the pebbly
base of the Red Chalk is generally the only relic of this period, but
in a few places the conglomeratic band thickens locally into a sandy
deposit resembling the Carstone of Lincolnshire, and like it sepa-
rable from the overlying Red Chalk.” Of this the best example
known to me occurs at the head of Scotten Dale, the deep valley
east of Kirby Underdale, 13 miles E.N.E. of York.’ In this locality

1 See W. Hill, ‘On the Lower Beds of the Upper Cretaceous Series:
in Lincolnshire and Yorkshire, Quart. Journ. Geol. Soc. vol. xliv. (1888)
pp. 334-35.

2 J. F. Blake, Proc. Geol. Assoc. vol. v. (1877) p. 245.

3 The Rev. J. F. Blake seems to have been the first to call attention to this
interesting section, see Geol. Mag. 1874, p. 363, and op. yam cit. p. 246. See
also C. F. Strangways, Geol. Surv. Mem. ‘The Geology of the Country N.E..
of York and 8. of Malton,’ p. 25.

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 189)

at the time of my last visit the following section could with some
difficulty be made out on the steep southern side of the vale :—

Ft. In.
White chalk not well exposed.
6. Hard, pinkish and yellowish, nodular chalk ......... seenforabout 2 0
5. Deep-red and yellowish nodular chalk. Belemnites minimus and
fragments of Znoceramus abundant ............... seen forabout 2 0
4. Soft, shaly, red chalk ...... Pres MRAee eee ae Meas att cnaeed eevee ot 0 3
3. Hard, gritty, nodular red chalk. B. minimus abundant............ 1 0

2. Yellow clayey marl with ferruginous grains. B. minimus and
Terebratula, sp. were found at this horizon apparently in place ;
but the conditions suggested a slight possibility of their having
been washed down from the overlying red chalk............ about 1 0
1. Coarse, pebbly, ferruginous sand of deep-brown colour wellseen for 3-6
Total thickness probably about 12 feet. Pebbles range up to 2
inches in diameter, composed of oolitic ironstone and phos-
phatized nodules, with small black shining ‘ lydites,’ quartz-
grains, etc.
Dark blue clay, referred to the Upper Lias.*

In this section the marly layer, No. 2, which appears to contain
sparingly certain characteristic Red Chalk fossils, distinctly suggests
a passage downward from the Red Chalk into the underlying un-
fossiliferous ferruginous sands; and the latter deposit so closely
resembles the Lincolnshire Carstone in its general appearance and
in its relationship to the Red Chalk that I think we may un-
hesitatingly accept the Rev. J. F. Blake’s proposal that it should be
correlated with the Carstone.

Mr. W. Hill has suggested” that the character of the base of the
Red Chalk in general may be explained as resulting from the
‘working up’ of the underlying material during its deposition.
But 1 think that in the above section, as at Knapton and at Speeton,
there is good evidence for an actual downward passage at this.
horizon. ‘The Yorkshire sections are thus in agreement with
those of Lincolnshire, in which county, as Mr. A. Strahan has shown,”
there is everywhere the closest stratigraphical relationship between
the Red Chalk and the underlying Carstone, often with clear proof of
a gradual passage from one to the other.

Traces of deposits similar to that of Scotten Dale occur in various
places both north and south of this locality, as at Wharram,’
Leayening,’ Givendale®, etc., but always of greatly reduced thick-

1 Mem. Geol. Surv. ‘Country N.E. of York and S. of Malton,’ p. 10.

2 W. Hill, Quart. Journ. Geol. Soc. vol. xliv. (1888) pp. 338, 355.

3 A, Strahan, ‘On the Relations of the Lincolnshire Carstone,’ Quart. Journ.
Geol. Soc. vol. xlii. (1886) p. 486, also Mem. Geol. Surv. 1888, ‘Country around
Lincoln,’ p. 105. In these opinions Mr. A. J. Jukes-Browne does not concur
(Mem, Geol. Surv. 1887, ‘ Hast Lincolnshire,’ p. 15, footnote). After examining
most of the Lincolnshire sections, however, I am convinced that Mr. Strahan’s
views on this matter are correct.

4 J. F. Blake, Proc. Geol. Assoc. vol. v. (1877) p. 245.

5 W. Hill, Quart. Journ. Geol. Soc. vol. xliv. (1888) p. 341.

6 J. F. Blake, Geol. Mag. 1874, p. 362.

190 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

mess and insufficiently exposed for study. In its still more
attenuated form, as the pebbly basement-layer of the Red Chalk,
it was revealed a few years ago in the railway-cutting of the
Market Weighton and Driffield branch east of Goodmanham, being
here of very coarse texture, with fragments of phosphatic stone and
coarsely-gritty oolitic iron-ore, up to 3 or 4 inches in diameter.
In this vicinity the unconformability at the base of the Upper
Cretaceous rocks reaches its extreme stage, the underlying strata
being shaly limestone of Lower Lias age; and in going farther
south we find that the higher members of the Jurassic series emerge
again in succession.

In the extensive cuttings near Drewton, 4 miles north of the
Humber, on the Hull and Barnsley railway, the base of the Red
Chalk was at one time excellently exposed, and is still partially
visible. These sections while still fresh were examined by
Messrs. W. Keeping and C. 8. Middlemiss, who record the following
details * :—

Feet. Inches.
Nodularmed chalk oo oscsccse-aes
Pale nodular chalk 2:..ass.-...4--
Clawey red chalk sog..0.2cc-secme
Grey nodular chalk ........ ais oats
Red chaliiey j..2.0 icaaseaee akc

YVellow-green clay .....:..tenicsce-
Unetuous'red clays) j--7s2.82--

SS SD
So © 09 DS OS Gd Od

resting on a ‘dark, almost black clay, slightly shaly .... probably
the Kimeridge Clay, but characteristic fossils were not obtained.’

It has been suspected that the uppermost portion of the dark
clays beneath the above may represent some portion of the Speeton
Series,” and the clayey character of the base of the Red Chalk
seems to favour the supposition. But a careful search has failed to
reveal any evidence of the presence of the Speeton fauna, the first
fossils met with below the Red Chalk being, as Messrs. Keeping
and Middlemiss pointed out, undoubtedly Jurassic forms, including
Belemnites abbreviatus and B. Owenii. On general considerations,
however, it seems just possible that some of the unfossiliferous clay
immediately below the Red Chalk may represent the sparingly
fossiliferous marls with Belemnites minimus (A) which have been
shown to occupy this horizon at Speeton and Knapton, though, as
one of the cuttings still exhibits traces of a pebbly band at the base
of the Red Chalk, it is more likely that the Speeton Series is entirely
absent at this point.

Nearer the Humber, in a small pit in the dale north of Ellough-
ton, the Red Chalk is seen to contain numerous small pebbles, and
probably has a similar pebbly base, the underlying deposit again
being dark clay, supposed to be Kimeridge Clay.

1 “On some New Railway Sections and other Rock-Exposures in the District
of Cave, Yorkshire,’ Geol. Mag. 1883, p. 218.

2 A. Harker, ‘ The Oolites of the Cave District,’ The Naturalist (Leeds), 1885,
‘p. 231.

Wel) ozs) IN YORKSHIRE AND LINCOLNSHIRE. 191

The sum of the available evidence regarding the inland extension
of the Speeton Series in Yorkshire indicates, therefore, that these
rocks undergo a rapid attenuation as a whole in a westerly direc-
tion, and that all disappear within 14 miles of the coast except the
uppermost division (Belemnites minimus-marls: Zone A), which
persists as the pebbly or clayey basement-layer of the Red Chalk,
swelling locally into a thicker deposit of ferruginous sand akin
to the Lincolnshire Carstone.

The data are insufficient to prove whether the Lower Cretaceous
Clays end off against the edge of their basin of deposition, and are
simply overstepped by the Upper Cretaceous strata; or whether
a true unconformability, as in so many other parts of the country,
is developed in them at this horizon. That erosion took place in
the western part of the district before the deposition of the Red
Chalk is indeed certain; but it is not certain that the clays of the
coast-section ever extended so far westward.

LY. Tar Speeron Series In LINCOLNSHIRE.

a. General Observations and Bibliography.

With respect to the Lincolnshire sections my present purpose has
regard for the sequence of the rocks rather than for their local
stratigraphy ; and as the whole area has been recently examined and
reported upon by the officers of the Geological Survey, whose maps
and memoirs* afford all the necessary information bearing on the
mode of occurrence and extent of the various strata to be considered,
it will be neither requisite nor desirable that I should reiterate
such details. My aim therefore will be to give the broader out-
lines only of the general stratigraphy, but to enter more fully into
the paleontological and other evidence which may afford the means
for the correlation of the rocks in question with the more easily
classified clays of the Speeton section. And indeed, though during
the course of my field-work in this area I have gone repeatedly
over the whole extent of the Lower Cretaceous outcrop, I have
concentrated my attention chiefly on such places as promised the
best palzontological results. The most suitable localities for this
purpose have proved to be the broken escarpment near Acre
House, with its abandoned iron-ore workings; the limestone-pits of
Normanby, Walesby, Tealby, and Willingham; the fine railway-
cutting sections on either side of Donnington-upon-Bain ; and the
brickyards and sand- and sandstone-pits of the Spilsby district.

Of the paleontological material collected only a small portion can
be adequately dealt with at present, but fortunately the cephalo-
poda are sufficiently abundant and characteristic to allow of definite

1 Sheets (one inch) Nos, 86, 84, and 83. Memoirs, ‘ North Lincolnshire and
South Yorkshire’ (Sheet 86); ‘Country around Lincoln’ (Sheet 83); and
* Hast Lincolnshire’ (Sheet 84).

‘192 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

conclusions being drawn respecting the correlation of these Lincoln-
shire deposits with the Speeton Series of the Yorkshire coast,
thereby clearing away certain prevalent misconceptions and pro-
viding a safer basis for future discussion of their age and origin.

These beds seem to be unrepresented at the northern extremity
of the Lincolnshire Cretaceous escarpment, the pebbly base of the
Red Chalk in the vicinity of the Humber resting, so far as is known,
directly on the Kimeridge Clay.’ About 6 miles south of that
estuary, however, thin sands and clays intervene for a short space
between the Kimeridge Clay and the Chalk, but are not well
exposed, and are soon again altogether lost beneath the over-
lapping Chalk. They reappear in stronger force after a further
interval of about 5 miles; and thenceforward, from the neigh-
bourhood of Caistor, are continued southward, gaining steadily in
importance, up to the southern termination of the Chalk escarpment,
8 miles north of the Wash, where the drift and alluvium of the
low ground enshroud them.

Where best developed the diverse lithological characters of this
series have afforded a ready and simple method of subdivision which
has been adopted by all its investigators. These divisions are
shown in the Table printed on p. 194, in which the results of previous
workers are stated and compared.

In addition to the papers mentioned in the Table, Mr. H. Keeping
gave in 1882 a short but valuable account of the series,’ and
especially of the sections on the Louth and Lincoln railway,
now in great part obscured, from which he had in 1872 secured a
large collection of fossils. His classification is essentially that of
Prof. Judd and the earlier observers; but he seems to have
been the first to call attention to the band of phosphatic nodules at
the base of the Spilsby Sandstone, and his fossil lists are in many
respects in advance of those of his predecessors, though herein, as
in all the other paleontological lists of the area yet published,
the confusion of Belemnites brunsvicensis with B. lateralis,’ and the
vagueness of the specific names employed for the ammonites, seriously
impair their value as aids to the correlation of the deposits.

The detailed comparisons of the Speeton section with the Lincoln-
shire deposits previously put forward are shown in the Table facing
this page.”

1 A. Strahan, ‘On the Lincolnshire Carstone, Quart. Journ. Geol. Soc. vol.
xlii. (1886) p. 489. rf

2 H. Keeping, ‘On some Sections of Lincolnshire Neocomian,’ Quart.
Journ. Geol. Soc. vol. xxxviii. (1882) p. 239.

3 The same error pervades nearly all the fossil-lists given by Prof. Judd and
the Survey, and also affects the Continental lists in Judd’s paper in Quart.
Journ. Geol. Soc. vol. xxvi. (1870) p. 326.

4 The correlation given in the late Mr. W. Keeping’s ‘ Fossils, etc., of Upware
and Brickhill’ (Cambridge, 1883), p. xi, is omitted, being practically a repro-
duction of that of Prof. Judd. There is also a brief correlation by Mr. A. J.
Jukes-Browne in his paper ‘On the Application of the term Neocomian ’
(Geol. Mag. 1886, p. 311), based upon Prof. Judd’s account of the Speeton
sections.

[To face p. 192.

RE INFRA-CRETACEOUS S

5 et Crétacées de la
istes de Moscou,

LINCOLNSHIRE.

hes sablonneuses su-
rieures (upper sands)
présentant JlAptien,
partie remanié.

caire de Tealby a Pec-
n cinctus et Belemnites
micanaliculatus.

ile de Tealby & Olco-
ephanus speetonensis.

he ferrugineuse de
ee a Hoplites nori-

bs de Spilsby avec Be-

nites lateralis, Phil.
orpulentus, Nik.), et
leostephanus stenom-
ralus.

rtlandien inférieur,
struit a l’époque de ia
rmation (e gres de
ilsby-)

riles schisteuses avec
ucella Pallasi, Peri-
hinetes Quenstedti, et
itres périsphinctes
pmprimés.

uches & Hoplites eu-
orus, H. pseudomuta-
lis, et Exogyra virgula.

G. W. Tiles de Speeton et leurs équivalents,’ pt. iii., Bulletin
a e Moscon, vol. v. n.s. pp. 181 & 455. 1891-92.
et le

LINCOLNSHIRE.

ZONE ‘pies

Calcaire de Tealby.

at

rcheni

ZONE invereus Argile de Tealby.

Aatieria Partie supérieure de la roche ferrugineuse de
Claxby 4 Hopl. regalis et Bel. jaculum.

Partie inférieure de la roche ferrugineuse de

ms er Claxby 2 Olcostephanus Blaki, Belemnites
: russiensis, etc,
ZONE.
(inch agit :
?| Gres de Spilsby & Olcostephanus subditus.
a |
) Schistes & Discina latissima et & ammonites
erarina écrasées.
?
|
Zon}
Ki
lis. Schistes Kimméridgiens.

Quart. Journ. Geol. Soc. Vol. LIT.

J. W. Judd in * Additional Observations on the Neocomian Strata,’ etc.,
Quart. Journ. Geol. Suc, yo). xxvi. p. 331. 1870.

CoMPARISONS OF THE YORKSHIRE AND LINCOLNSHIRE JNFRA-CRETACEOUS STRATA BY THE VARIOUS AUTHORS UNDERMENTIONED.

Geological Survey in ‘The Geology
of the Country around Lincoln’ *
(Bxplan. of Sh. 83), p. 88. 1888.

A. Pavlow in ‘&tudes sur les Couches Jurassiques et Crétacées de la

|
Russie,’ Bulletin de la Soc. Imp. des Tavurblistes de Moscou,

G. W. Lamplugh in ‘ On the Speeton Clays and their Equivaldnts in Lincoln-
shire,’ Abstract in Report Brit. Assoc, 1890, p. 808, also in ‘ Argiles de Speeton

A. Pavlow (Pavlow & Lamplugh) in

NS ee

[To face p. 192.

‘Argiles de Speeton et leurs équivalents,’ pt. iii., Bulletin

de la Soc, Imp, des Naturalistes fe Moscon, vol. y. n.s, pp. 181 & 455. 1891-92,

ACRE House, LINCOLNSHIRE.

|
SPEETON. j
|

LINCOLNSHIRE.

|
Red Chalk, |
Carstone,
;
Tealby Limestone. B.—Zone a Hoplites Deshayesi et Belennites -
banat Caleaire de Tealby.
C1 to C6.—Zone & Olcostephanus Decheni
et speetonensis. Arpile de Tealb
Cand C7.—Zone ft Olcostephanus subsiversus| ‘gue de Tealby.
Tealby Clay. SULLA EAU
C8 to C1l.—Zone & Hoplites regalis : ia| Partie supérieure de la roche ferrugineuse de
Astieri (type); B. jaculum. iz Claxby & Hopl. regalis et Bel. jaculum.
ifpr-| Partie inférieure de la roche ferrugineuse de
D1 to D 3.—Zone a Olcostephanus gravesifor-' g A
mis, O. Keyserlingi; Belemnites later ee ete. SY, oe (Gleostephanias Blaki, Belemnites
Claxby Ironstone. }

Spilsby Sandstone.

i =

D. 4 to D. 8.—Zone & Olcostephanus
cf. subditus, ete,

agilis,

Gres de Spilsby & Olcostephanus subdilus,

* Coprolite-Bed.’

Upper Kimeridge Shales.

* See footnote on p, 193. p.55. 1889. et leurs équiyalents,’ Moscow, p. 210. 1891.
YORKSHIRE. LINCOLNSHIRE. eae LINCOLNSHIRE. ZONES. YORKSHIRE. | LINCOLNSHIRE. SPEETON, YORKSHIRE.
GaAvLt.
(Albien, d’Orb.) j Hunstanton Red Rock. | Hunstanton Red Rock. Red Chalk,
% ZONE A.—Marls with Belemnites
UNCONFORMITY, minimus.
= ( Carstone, with Couches & Hoplites Des-|Rovhes sablonneuses su-
Upper NEOCOMIAN. | 2 ft. derived Neoco- Z. & Hoplites Des- hayesi de Speeton (Néoc. périeures (upper sands) ce
(Aptien, @Orb., Rho- Black clays ae 120 Upper Sands? Absent. mian fauna, hayesi. supérieur de Judd). pepresentant pu eeeay
anien and Aptien, | |-/2° Peder 30) ppartie Reman: ZONE B.—Zone of Belemnites (semicana-
Renev.) \ Cement-beds liculatus ?=) brunsvicensis.
Z. & Pecten cinctus.|Couches & Pecten cinctus|Calcaire de Tealby a Pec-
(Lesammonitessont| (large var.), Ancyloceras| teh cinctus et Belemnites|
encore peu étudiés.)| Duvalii, Meyeria ornata.| semicanaliculatus.
(\Dark blue clay with
MIDDLE NEOCOMIAN. || few fossils (‘zone of ¢ 80,
. || Pecten cinctus’)....-. a
(Urgonien, d Orb., Bar- A Couches & Olcostephanus|Argile de Tealby & Olco-'
een & Deni Ble nye eS “alt Healy Benes aye, Cee Cena epeatonenae Caos stephanus speetonensis. ZONE O.—Zone of Belemnites jaculum.
Cog. ; imestones, and oolitic' 7 3 “| et venustus) et Belem-| |
4-) | beds’) -....s.-.-0 */ 2,| ironstones, With many) if Tealby cutafalontie. nites Jasikowt, Lah.
|Clays with septaria... 30) ¢,-ci}5. | Limestone.
Upper /( 3
| e | a Tealby Clay.
is) A :
Middle + © |4 ay Z. % Hoplites Noa Couches & Hoplites nori-\Rovhe ferrugineuse de
BL 1 ( f 2 | 3 Claxby ee | cus et Hdlemnsiss jacu-| Claxby a Hoplites nori-
ue clays (‘zone 0! i ill. E). cus. co 5
f Ammonites spee-| 200 e | Spa (type). ete Zone D.—Zone of Belemnites lateralis
Lower NEOCOMIAN. | tonensis’) eal Tomer : (including ZonE E, Coprolite-Bed),
(Néocomien, d’Orb.,4 Bing clays aezone OH 50 Spilsby
- ae Té, - NOTWCUS’) — ....- ‘ : 4
Valanginien & Neo- | Blue pyritie clays) |Lower Sands and Sand- \ Sandstone. |\7 3 lateralis (cor-|Couches A B. lateralis fee ile Bpibeyaredree
comien, Desor.) A fA. Asli 50) stones? Tentus) et Olcost Phill.(corpulentus,Nik.),| lemnites lateralis, il.
\| (zone of A. As eA puten halus. Port.| Qlcostephanus subditus, (corpulentus, Nik.), et
TUANUB”) ..srerceseecese Hee a da ol +! Orynoticeras catenula- Oleostephanus stenom-
andien supérieur. nit, phalus.
|
Portl. siveene et pase pegielangicay “nike,
., NCON {ITY . & Olcostephanus| la plus supérieure du; détruit oque de la
inom CeHey pT: Leo eeie ae Peri- Tinimeridgen détruits’ formation uu pres de
sphinctes bononien-| et remplacés par un lit) Spilsby.)
sis. Portlandien| de rognons _phospha-
moyen. snes sree Belemnites
i absolutus.
B 1c, \Portlandian Clays, ete. |Kimeridge Clay.
siaes | se lh e ZONE i Binminone iehalee (UP er
isphi. Schistes bitumineux ayec\Arjiles schisteuses ayec Kimeridge of English geologists).
Ze i ees Perisph. du groupe vir-| Aucella Pallasi, Peri-
dil a 5 aR s tl Gel gati, Lingula ovalis, sphinctes Quenstedti, et)
rae Gaiee anc! ‘Discina Humphriesiana| autres périsphinctes
TEAC a (latissima). comprimés.
Z. & Hoplites eudorus|Gouches & Hoplites eudor-' Couches & Hoplites eu-
et Bzogyra virgula.| us et Bzogyra virgula. | ddcus, H. pseudomuta-
ISR ERE gy ¢ Z
Kimmenridgien. bilis, et Hxogyra virgula.

Schistes & Discina Jafissima et § ammonites

Couches F A Belemnites magnificus, porrectus, ecrasées,
et & ammonites écrasces.
Couches & Hoplites pseudonutabilis. Schistes Kimmeéridgiens.

Vol. 52.] 1N YORKSHIRE AND LINCOLNSHIRE. 193

The scheme first proposed by Pavlow in 1889, after his pre-
Jiminary study of the fossils of the deposits, and afterwards more
fully stated and slightly amended in 1891-92, is substantially that
which I brought before the British Association in 1890, and repro-
duced in‘ Argiles de Speeton et leurs Equivalents’ in 1891; and
‘between this and the propositions of the previous workers there are
radical differences.’ Further investigation has fully confirmed the
correlation suggested by Pavlow and myself, and it is now sought
to place on record the field-evidence, not heretofore published, by
which the comparison is sustained. Amid the general discussion
of this evidence some side-issues will be debated which are of much
consequence to the right understanding of the relations of the series
as a whole. The deposits will be considered in their upward
-stratigraphical sequence.

b. The Kimeridge Clay.

In comparing the Yorkshire and Lincolnshire areas we possess in
the Kimeridge Clay an admirable base-line.

Though, owing to the crushed condition of the fossils in both
districts, the list of recognizable species in common is short, the
-general similarity in position and composition is so close that no
reasonable doubt can exist that the bituminous shales* which
underlie the Spilsby Sandstone everywhere to the southward of
Caistor in Lincolnshire are the equivalents of the similar shales
(Zone F) underlying the ‘ Coprolite-bed’ (Zone E) of the Speeton
section, and were laid down in the same basin of deposition.

It is indeed possible that the uppermost portion of this deposit
may have been locally removed by erosion in certain areas in Lin-
-colnshire previous to the deposition of the Spilsby Sandstone, since
the researches of the Geological Survey have gone to show that
there is a definite unconformable overlap of that rock in the
northern part of the county;* and the absence, so far as is yet
known, of the large belemnites of the Owenzi-group (Belemnites
magnificus, Puzosi, etc.), which occur at Speeton at the top of the
bituminous shales, may perhaps be thus accounted for. These
fossils are, however, by no means common even in the shore-expo-
sures at Speeton, and it may well be that their apparent absence
in Lincolnshire arises only from the lack of good collecting-ground
at this horizon.

1 With respect to the Geological Survey publications, it is to be noted that
the Lincolnshire deposits containing Belemnites lateralis are fully described
in the recently-published Mem. Geol. Surv., ‘The Jurassic Rocks of Great
Britain,’ vol. v. (pp. 286 e¢ segq.), and the corresponding portion of the Speeton
Olay in vol. i. (Yorkshire) of the same series, and this seems to imply an
acceptance of the views of Prof. Pavlow respecting their age, though no
very definite opinion is in either case expressed. See second division of
Table of comparisons.

? For further information regarding the Kimeridge Olay, see J. F. Blake,
Quart. Journ. Geol. Soc. vol. xxxi. (1875) pp. 196-233; T. Roberts, zbéd.
vol. xlv. (1889) pp. 545-560, and Geol. Surv. Mems., jam cit.

* Mem. Geol. Surv. 1888, ‘The Country around Lincoln’ (Sheet 83), p. 82.

[May 1896,

MR. G. W. LAMPLUGH ON THE SPEETON SERIES

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Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE, 195

But, with this reservation respecting the uppermost part, we may
safely state the general equivalency of the Upper Kimeridge deposits
of Yorkshire and Lincolnshire.

c. The Basement-bed of the Spilsby Sandstone.

The base of the pale greenish or reddish quartzose sand or
sandstone which overlies the Kimeridge Clay everywhere in Lin-
colnshire southward of Caistor is marked by the presence of
numerous dark phosphatic nodules, usually from 1 to 3 inches in
diameter.

At Speeton there is at the same horizon a similar though more
compact band of ‘ coprolites ’ (Zone E), and in this respect the two
areas are distinctly comparable. These nodules, first noticed as
above mentioned, by Mr. H. Keeping in a railway-cutting near South
Willingham, were afterwards traced by the officers of the Geological
Survey over an extended area,’ and by them were considered to be
derivative pebbles marking the destruction of pre-existing deposits.
It appears to me, however, that the derivative character of these
nodules is exceedingly doubtful, this view being liable to the same
objections as apply under similar circumstances at Speeton.?

The composition of the so-called pebbles tells strongly against
their derivative origin. Wherever I have been able to examine
them they have been of uniform character, without admixture, and
have all presented the same dark phosphatic exterior and eroded
aspect. But in many instances when broken open they reveal a
gritty interior not unlike that of the overlying sandstone, and when
dissolved in acid they leave an abundant residue of somewhat coarse
quartzose sand, which distinctly suggests their original accretion
in a sandy matrix like that now enclosing them, and is not
to be reconciled with the idea that they were once concretions
in the Kimeridge Clay. Moreover at Speeton, where the nodules
are enclosed in pyritous clay, the only residue obtained on dissolving
them is a little dark fetid mud with groups of angular pyrites-
crystals and a very little fine sandy silt. They occur in both
localities mostly in the form of more or less obscure casts of shells and
portions of the whorls of ammonites, sometimes riddled with the
tube-like cavities of boring molluscs; and these fossils, when
recognizable, are distinctly not such as characterize the subjacent
strata or any other deposit of a lower horizon now existing in the
areas. The specific determination of these casts is of course full
of difficulty and uncertainty, as is shown by the state of the lists
published in the Geol. Surv. Mems.* from the collection made in
Lincolnshire by Messrs. A. J. Jukes-Browne and M. Staniland. The
lists contain a total of nineteen determinations; but in only eight

1 Mem. Geol. Surv. 1888, ‘The Country around Lincoln,’ pp. 89 e¢ segq., and
ibid, 1887, ‘ East Lincolnshire,’ pp. 15 e¢ segq.

2 «Subdivisions of the Speeton Clay,’ Quart. Journ. Geol. Soc. vol. xlv.
(1889) p. 586.

® « Hast Lincolnshire,’ p. 139; ‘ Country around Lincoln,’ p. 93.

Q.J.G.8. No. 206. P

196 MR. G, W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

instances is the species stated, the remainder giving the genus alone.
Moreover a footnote is added to the lists expressing great hesitancy
in the identifications. The following are the fossils mentioned :—

Species: Terebratula ovoides, Sbhy., Waldhemia Woodwardii,
Myacites recurva, Lucina portlandica, Sby., Thracia Phillipsia,
Roem. (or depressa, Sby.), Ammonites biplea, Sby., A. plicatilis, and
A. speetonensis, Y. &

GENERA: Arca, Sp., ups Cyprina, Cucullea, sp., decane
Lima, sp., Pectunculus, sp., Trigonia, sp., Natica, sp., Pleurotomaria,
sp., Belemnites, sp.

In discussing this list we may at once dismiss the genera, re-
marking only that the rotund form of the casts, the presence of the
impression of both valves in the case of bivalves, the absence of
fragments of oysters and other characteristic hard fossils occurring
abundantly in the underlying strata, and the general facies of the
assemblage, are all points which tell against the derivative origin of
the nodules. But when we turn to the consideration of the
species above-mentioned, we do not find any better evidence in
support of the statement that ‘there can be no doubt that most of
the phosphates have been derived from the Kimeridge Clay’ (‘ East
Lincolnshire,’ p. 139). Terebratula ovoides, Sby., if it be the
species mentioned by Mr. W. Keeping,’ has been found in blocks
supposed to have been derived from the Spilsby Sandstone, and
also in a phosphatized condition at Upware, Brickhill, and Potton,
and therefore if the species be rightly determined the evidence is
entirely against its derivative character. Waldhemia Woodwardit,
Walker, is not known to exist in rocks of alower horizon. Myacites
recurva is referred to at the foot of the list as being a form which
‘might equally well be Panopwa neocomiensis; and on the other
hand Thracia Phillipsit may well be Th. depressa of the Kimeridge
Clay.’ Lucina portlandica occurs commonly at Speeton as a cast
in the ‘ Coprolite-bed’ (Zone E), and appears to be confined to this
horizon both in Yorkshire and Lincolnshire. Ammonites biplex, as
the name is usually applied in England, is almost without deter-
minative value even when the specimens are well preserved, since
almost every round-whorled ammonite with bifurcating ribs, from
whatever horizon, has in turn received the title, whether it be
of the genus Perisphinctes or Olcostephanus or what not. In some
of our public collections, for example, specimens from the Upper
Kimeridge have been mixed with others undoubtedly from the
‘Zone of Ammonites speetonensis’ of the Speeton Clay under the
common name of A. biplex.? A. speetonensis stands in exactly
similar case, being a much-abused species into which it has been
the fashion of English paleontologists to thrust almost any
form of the genus Olcostephanus that had the misfortune to be
found anywhere between the base of the Red Chalk and the top of

1 W. Keeping, ‘ Fossils of Upware, etc., Cambridge, 1883. pp. 34-37.

2 See Quart. Journ. Geol. Soc. vol. xlv. " (1889) p. 613. The last-mentioned
form, Ammonites concinnus of Phillips, is recognized by Pavlow as including
Olcos ‘tephanus (Simbirskites) subtnversus, M. Pavl., and other allied species.

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIREs 197

the Kimeridge Clay. A. plicatilis, another ‘difficult species,’ is
usually considered an Oxfordian and Corallian form, and under
the circumstances the value of the determination is altogether
doubtful. These fragments of ammonites are in fact similar to
those occurring abundantly in the ‘ Coprolite-bed ’ () of Speeton i
like preservation, which Prof. Pavlow has studied and illustrated in
‘ Argiles de Speeton’ (pl. 11. & pp. 114 and 115), and considers to be
the relics of a fauna not otherwise represented in the section.
The species he has identified from Speeton are given in the Table
of Cephalopoda facing p. 184. Thus we see that both the composition
of the nodules and their fossils tell strongly in favour of their
original accretion at their present horizon.

The weakness of the fossil evidence for their derivative character
was evidently felt by the writer of the ‘East Lincolnshire’
memoir, who therefore puts forward the further suggestion that ‘it
is just possible that there were certain older Neocomian beds
(destroyed before the deposition of the Spilsby Sandstone), and that
some of the casts were derived from them.’ But as it will presently
be demonstrated that the Spilsby Sandstone represents the lowest
horizon of the Speeton Clay (which has been shown by recent re-
searches to be older than any known Neocomian rocks and more
closely allied to the Jurassic than to the Lower Cretaceous), and as
the paleontological evidence demonstrates that there are no beds
missing at this horizon in Lincolnshire which occur in Yorkshire,
where, if my reading of the section be correct, there is practically
an unbroken record from Jurassic to Upper Cretaceous times, it
is difficult to believe that the supposed beds can ever have existed
in the area.

Except in one particular, the nodule-bed of Lincolnshire is indeed
in all respects analogous to the ‘Coprolite-bed’ of Speeton, the
difference being that while the latter occurs as a band in the midst
of a conformable clayey or shaly series, and does not mark any
striking lithological change, the former is developed along a very
important stratigraphical horizon at which the great clayey series
of the Middle and Upper Jurassics gives place to the coarse sandy
deposit forming the Spilsby Sandstone, a change evidently be-
tokening a wide-reaching revolution in the physical conditions of
the region. There seems moreover, as already stated, to be
evidence of actual erosion and unconformability at this horizon as
we approach the Humber,’ and it is therefore the more remarkable
that the nodule-bed should not contain better indications of the
destruction of the older strata if any ‘ pebbles’ were really derived
therefrom. But all the arguments which at Speeton’ tell in
favour of the formation of these phosphatic stones as nodules con-
temporaneous with the deposit have equal strength in Lincolnshire.
In both districts the stones, though most abundant at a definite
horizon, are by no means confined to it, but occur at other levels,

1 See Geol. Surv. Mem. 1888, ‘ Country around Lincoln,’ p. 82.
? Quart. Journ, Geol. Soc. vol. xlv. (1889) p. 584.
p2

198 MR. G..W. LAMPLUGH ON THE SPEETON sERIES [May 1896,

or sparsely scattered throughout the series; they contain certain
fossils proper to the bed in which they occur; and their eroded
surfaces show less appearance of rolling than of corrosion from the
attack of various destructive organisms inhabiting the sea-floor;
whose activity is similarly manifest on the undoubtedly indigenous
fossils of the deposits.

The subject thus raised has broad bearings, and if my view be
correct there are many localities other than those now in question
where a revision of the evidence for the derivative character of the
‘ phosphate-stones’ is desirable. JI am satisfied, for instance, from
a recent examination at Hunstanton of the mode of occurrence
of Hoplites Deshayesti and other fossils thus preserved towards the
base of the Carstone, that these are proper to the deposit and not
derivative;! and a study of the literature relating to the ‘ phosphate-
beds’ at Potton, Wicken, Upware. etc.,? shows that most of the
investigators of these localities have found it necessary to allow that
some at any rate of the nodular material is not older than the bed
in which it occurs.

It is not my purpose, however, to pursue the wider question on
this occasion,* andI shall content myself for the present by restating
my conviction, based on a careful study of the various types of
nodules and concretions marking the different horizons of the
Speeton Clay, that some of these, including the dark phosphatic
stones, have gathered in the mud of the sea-bottom, and have formed
hard masses before the accumulation of the overlying strata,* and
that the comparative rarity or abundance of concretions of this type
affords a rough measure of the rate of deposition of the enclosing
material.

The investigations of the Challenger expedition” have taught
us that the formation of nodules both of phosphate and manganese
is still taking place in areas of slow deposition beneath our existing
oceans, and from the description given of the former they appear to
agree remarkably in shape, size, and general characters with those
under consideration. It is true that the conditions are in many
respects not analogous, but the phenomena are probably, none the:
less, closely illustrative of those of our Jurassic and Cretaceous seas,
wherein the marine sediments seem to have been characterized by

+ See reference to these in W. Keeping’s ‘The Fossils of Upware and
Brickhill,’ Cambridge, 1883, p. 57.

? Among other works see J. J. H. Teall,‘ The Potton and Wicken Phosphatic
Deposits’ (Cambridge, 1875); W. J. Sollas, Quart. Journ. Geol. Soe. vol. xxix..
1873, p. 76; W. Keeping, op. yam cit. p. 17. See also the discussion between
Walker. J. F.(Ann. & Mag. Nat. Hist. ser. 3, vol. xviii. 1866, pp. 31 & 381, and.
xx. p. 118), and H.G. Seeley (Ann. & Mag. Nat. Hist. ser. 3, vol. xviii. p. 111, and.
xx. p. 23); and O. Fisher, Quart. Journ. Geol. Soc. vol. xxix. (1878) p. 52.

° For an excellent summary of our knowledge on this subject, with extensive
bibliography. see R. A. F. Penrose, Jun., ‘Nature and Origin of Deposits of
Phosphate of Lime,’ Bull. U.S. Geol. Surv. vol. vii. no. 46 (1888), p. 475.

4 At the meeting of the Geol. Soc. previous to that at which this paper was
read, Messrs. A. J. Jukes-Browne and Hill put forward a very similar explana-
tion for the phosphatized fossils and nodules of the ‘ Cénomanien.’

° Challenger Reports, ‘ Deep-Sea Deposits’ (London, 1891), p. 391.

Vol. 52.] © IN YORKSHIRE AND LINCOLNSHIRE. 199

an exceptionally high percentage of phosphoric acid.! After such
nodules were formed 4 local increase in the strength of the current
appears often to have wafted away the matrix, and the harder matter
‘was thus exposed to the corrosive action of the sea-water and its
denizens, producing on the nodules a misleading appearance of wave-
erosion.

As to the length of the pause.in the sedimentation denoted by
-these bands of nodules, we can judge only from the evidence of
other regions where the interval is more fully represented, or from
-the change to be noted in the fauna of the strata above and below
such bands. In this particular instance Prof. Pavlow, as already
mentioned, believes that an ammonite-zone well developed in Russia
is at Speeton condensed into these 4 inches of nodular matter.

d. The Spilsby Sandstone.

The lithological and stratigraphical characters of this deposit
have already been sufficiently indicated. Where it occurs in the
condition of a loose sand the fossils exist only in the form of
obscure hollow casts; but it usually consists in part of irregular
concretionary masses, often extremely hard, in which fossils are
frequently abundant, though difficult to extract and sometimes
injured by crushing. The most prominent feature of the fauna is
the abundance of the bivalve mollusca, mainly referable to the
genera Pecten, Pinna, Lima, Trigonia, Panopea, etc., many of
which are well preserved. But a glance at the published lists? will
suffice to show the uncertain state of the nomenclature, and as it
is not in my power at present to give more precise information
regarding these fossils, I do not propose herein to discuss them further
than to state that I can recognize among them some forms which
occur at Speeton in the ‘ Pale Beds’ (D6 and 7) of the zone of
Belemnites lateralis,and that several species could be matched, I think,
in the Hartwell Clay and equivalent Jurassic strata farther south.°

1 Considering the clear evidence which we now possess of the alternating en-
croachments of a northern and a southern fauna into certain parts of the North
' European basin during the epoch of the formation of the rocks between the
Kimeridge Clay and the Chalk, and the plentiful occurrence of phosphatic
-nodules where the northern and svuthern faunas meet, in the compound-

nodule band, D 1, at Speeton, the following passage in the Challenger Report
relative to the mode of occurrence of the recent nodules is at least worth
noticing (p. 896):—‘It may be pointed out that phosphatic nodules are
apparently more abundant in the deposits along coasts where there are great
and rapid changes of temperature, arising from the meeting of cold and warm
currents, as, for instance, off the Cape of Good Hope and off the eastern coast
of North America. It seeins highly probable that in these places large numbers
of pelagic organisms are frequently killed by these changes of temperature, and
. may in some instances form a considerable layer of decomposing matter on the
bottom of the ocean.’

? Geol. Surv. Mem. 1887, ‘East Lincolnshire, p. 140; H. Keeping, Quart.
Journ. Geol. Soc. vol. xxxviii. (1882) p. 241; Geol. Surv. Mem., ‘Jurassic Rocks
of Great Britain,’ vol. v. |

3 [Since this paper was read, Prof. Pavlow has described and figured Awcella
volgensis, Lahus., and Aucella volgensis, var. radiolata, Pavl:, both tound in the
‘zone of Ammonites stenomphalus’ in Russia, from the Spilsby Sandstone of
Donnington (see p. 215).—April 22nd, 1896.]

200 MR. G.W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

The cephalopoda are decidedly less abundant than the lamelli-
branchiata, but fortunately are still sufficiently numerous and charac-
teristic to provide safe grounds for the correlation. The belemnites
are widely, though scantily, distributed, and all the specimens yet
discovered are of the lateralis-type (Belemnites eaxplanatordes, Pavl. ;
B. lateralis, Phill.; B. russiensis, d’Orb.), forms occurring in the
lower part of Zone D at Speeton.

The ammonites, though less rare, are not, as a rule, well pre-
served. They have been referred by English paleontologists to
various species of obscure antecedents, such as Ammonites plicom-
phalus,' Sby.; A. mutabilis, Sby.; A. Kenigu, Sby.; A. rotundus,
Sby.; all names more or less vaguely applied in England, but
usually to Jurassic forms. More recently Pavlow* has identified,
among other species, Olcostephanus ( Craspedites) subcitus, Trautsch.,
a well-known Continental form of great value in the correlation.
At Speeton the corresponding horizon appears to be found in beds 5,
6, and 7 of Zone D. These are almost devoid of identifiable am-
monites,* but the correlation is, I think, well established by the
belemnites, combined with the evidence of the overlying and under-
lying strata. Ihave no doubt that, when the remaining branches
of the fauna have been more thoroughly studied, a relatively large
number of the species will be found to be common to the two
areas.

It is very probable, however, as will presently appear, that the
upper boundary of the Spilsby Sandstone is not everywhere of
exactly the same age, the accumulation of sandy material having
persisted longer in some localities than in others.

e. The Claxby Ironstone.

The paucity of sections in the Lincolnshire area is especially
detrimental when we attempt to deal with this deposit and the
overlying Tealby Clay. In the neighbourhood of Caistor, and for

1 As illustrating some of the difficulties of the paleontology it may be
noted that, of Sowerby’s two types of Ammonites plicomphalus now preserved in
the Natural History Museum, one is labelled as from ‘ Kelloway Rock, Boling-
broke,’ and the other ‘ Kimeridge Clay.’ Bothare ina matrix of Spilsby Sand-
stone. In all the collections, fossils from the different horizons in Lincolnshire
are much mixed,

‘ Argiles de Speeton,’ p.116 (sep. copy).

3 In collecting from the ‘Pale Beds’ (D6) at Speeton I have obtained
curious evidence of the former existence of large ammonites at this horizon.
Full-grown Hzrogyre (sinwata, var. cf. Couloni) are of common occurrence,
and one of these presented on one surface an excellent cast of a segment of
the imterior whorls and ribs of a large ammonite, to which the oyster had
evidently been affixed. The cast is insufficient for specific determination, but
shows clearly that the ammonite has not been of the deep-whorled Polypty-
chites-type such as tenant the overlying beds, but may have been akin to the
Craspedites-group of Olcostephani.

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 201

few miles farther south, the Spilsby Sandstone is capped by this
band of oolitic, clayey, and sometimes slightly gritty ironstone
crowded with fossils, which is about 15 feet thick in the brow of the
hill south of Nettleton, where it has been mined, but probably not
elsewhere so thick. In this locality both the upward and the down-
ward limits of the ironstone-rock are fairly definite, but it is usually
overlain by a clayey band crowded with oolitic ferruginous grains
which appears to contain the fauna of the ironstone along with a
few newer forms. Northward it seems to thin out and disappear
shortly before the accompanying strata are overlapped by the Upper
Cretaceous rocks near Clixby. In the opposite direction it is still
a well-marked feature in the series 12 miles south of Nettleton,
the railway-cutting at Benniworth Haven, near Donnington, de-
scribed by Mr. H. Keeping,’ revealing 9 feet of this rock, while
its original thickness may have been more than this; but farther
south it appears to merge more or less into a clayey deposit. At
the southern termination of the Wolds it is represented by irregular
- gritty ferruginous bands with deep partings of sandy clay. Last
of the Wolds it was recognized in the borings at Willoughby and
Skegness, and in both localities was interstratified and mixed with
clay.”

By Prof. Judd and the officers of the Geological Survey the
Claxby Ironstone is classed with the Tealby Clay ; but the earlier
observers, Messrs. Dikes and Lee, were inclined to connect it with
the underlying sandstone,? and Mr. H. Keeping observes that its
fossils ‘differ somewhat considerably from those of the clays and
limestone above’ (op. cit. p. 241). |

As in the Spilsby Sandstone, lamellibranchs are the most abundant
fossils. These are chiefly of the genera Hvogyra, Trigonia, Pecten
(including numerous individuals of the gigantic P. cinctus),
Cucullea, Lima, Panopea, etc.* Many of the species occur like-
wise in the underlying sandstone. Brachiopoda are also numerous,
especially in the Acre House section, where they seem to charac-
terize the clayey material immediately overlying the harder rock
(see section, p. 203).

The cephalopoda are represented by both ammonites and belem-
nites, but while the latter are of common occurrence, the former
are rare and poorly preserved. All the belemnites that I have
been able to observe in piace in the Ironstone, whether at Nettleton
Hill, Donnington, or Hundleby, have belonged to the lateralis-group
(including B. lateralis, Phill., B. russiensis, d’Orb., and B. sub-

* Quart. Journ. Geol. Soc. vol. xxxviii. (1882) p. 243.

? A.J. Jukes-Browne, ibid. vol. xlix. (1893) pp. 467 & 472.

3 Messrs Dikes and Lee’s description of the deposit is as follows :—‘ A mass
of small, globular, shining grains, of a dark brown colour, cemented together by
ferruginous matter; it occurs in the higher part of the bed [green sand and
sandstone] nearly at its junction with the grey stone; and, possibly, ought to
have been classed with it, Mag. Nat. Hist. ser. 2, vol. i. (1887) p. 565.

* Prof. Pavlow (op. cz#.) has recently recognized among these Aucella Keyser-
lingi, Lahus., a form well known in Russia.

202 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

quadratus, Roem.). But from the spoil-heaps of the abandoned
mines near Acre House I have also obtained a few fragments of
B. jaculum, along with two pieces of Ammonites (Hoplites) cf. regalis
(noricus of Judd) and a fragment of Olcostephanus, near Astver-
ianus, Q’Orb., which appear to have been embedded ina matrix of
clay with ironstone-grains.

. The ammonites collected, with the above exception, are all deep-
whorled Olcostephani (subgenus Polyptychites of Pavlow), including
Olcostephanus (Polyptychites) Blaki, Pavl.; O. (P.) Beant, Pavl.;
and O. (P.) cf. ramulicosta, Pavl.; which are all species charac-
terizing the upper part of the ‘Zone of Belemnites laterals’ at
Speeton.

These cephalopoda alone are sufficient to fix the correlation with
the Speeton section, and their evidence is confirmed by several other
fossils common to the two areas; among others being Ewogyra
sinuata, var. (a well-marked form which I think should rank as a
separate species), Astarte senecta, Bean MS., Pholadomya, sp., Arca,
sp., etc.. Many of the lamellibranchs, however, such as the 7’rigonie,
Cucullee, etc., and some of the brachiopods, which abound in the
Claxby Ironstone and the Spilsby Sandstone, have not been found
in the Speeton Clay, while other fossils, like certain species of:
Langula, Nucula, etc. which are plentiful at Speeton do not occur
in Lincolnshire. This differentiation of the contemporary faunas is
evidently the outcome of the different conditions of depth, nature of
sea-bottom, etc., prevalent in the two areas; and their mutually
complementary character at these and other horizons will prove of
the greatest value when the paleontology of the whole series comes
to be exhaustively studied.

_ The Claxby Ironstone as developed at Acre House and Donning-

ton may then be regarded as equivalent to the beds D1 to D4,.
forming the upper part of the ‘Zone of Belemnites laterals’
in the Speeton section; and the presence of the precursors of a
change of the fauna in its topmost clayey layer brings. the
stratum into the closest agreement with the Yorkshire beds, where
we find the same indications at this horizon in the Compound-
Nodule Band, D1.

From this correlation it follows that the paleontological affinity
of the deposit is altogether with the underlying Spilsby Sandstone,
although stratigraphically it seems to be more closely connected
with the overlying Tealby Clay. At Nettleton Hill it is clear that
the ironstone and associated ferruginous clay extend quite to
the top of the zone of Belemnites lateralis. That the striped clay
immediately overlying it contains a different fauna is well shown
by the following section, recently exposed by a slip in an old
quarry, at the second fence south of the old mine-buildings near
Acre House :—

Vol. 52.]} _ IN YORKSHIRE AND LINCOLNSHIRE. 203

Section exposed by a slip in the quarried escarpment south of
Acre House Mine.

Feet seen,
Striped pale and dark blue clay, slightly loamy, with pale
Tealby brown nodules with dark pyritous interior. Belemnites
Clay. jaculum (rather plentiful), Hxogyra sinwata (large typical
form), and other (undetermined) shells ............... about 10
( Clay crowded with oolitic ferruginous grains.
Claxby | B. lateralis (abundant) ; many brachiopods ...... about i
Iron- { Slightly gritty oolitic ferruginous rubbly rock, crowded with
stone. | fossils. 2B. lateralis, Pecten cinctus, Exogyra sinuata (small
) GUpMlAr VATIGLY), CLG, woods: xceaicoes>~ baw snokie ote rdervios about 7

Spilsby { Coarse greyish sand, indurated at the top, soft and inco-
Sandst. { herent below. B. lateralis, and casts of shells ... about 12

In the lower part of the Tealby Clay in this locality I have not
been able to find any ammonites or other discriminative fossils
except Belemnites jaculum, and am therefore unable to decide what
portion of the extensive zone of B. jaculum is represented ; but from
the presence, at a slightly higher level, of forms which at Speeton
make their first appearance 50 or 60 feet above the base of the zone,
and from the absence of some characteristic species of the ‘ noricus-
beds’? (C 9, 10, & 11), I am inclined to think that not only in this
section but throughout Lincolnshire the lower portion of the zone is
absent, except for that small portion of it which may be represented
by the clayey band forming the top of the Ironstone.

The unfortunate absence of sections prevents an accurate demar-
cation of the upward range of Belemnites lateralis farther south in
Lincolnshire; though at Donnington, as at Nettleton, its lmuit
must be at or about the top of the Ironstone, at which horizon
H. Keeping’ records Amm. noricus (Hopl. regalis). At any rate, the
pit in Tealby Clay at the brickyard adjoining the railway-station
there, which seems to be very little above the top of the Ironstone,
yields no other belemnites except jaculum; while the ammonites,
Olcostephanus (Simbirskites) wmbonatus, Lahus., and cf. Payeri,?
Toula, and other fossils found in it show that the horizon is at
least midway up in the Zone of B. jaculum (see p. 207). Nor,
so far as the scanty evidence tel]s, is there anywhere south of
this place any indication of B. lateralis in the clays above the Spilsby
Sandstone until we reach the southern extremity of the escarpment,
where just before the series disappears beneath the superficial
deposits of the Fenland, we find an important modification of the
conditions.

In this neighbourhood, from 1 to 2 miles west of Spilsby,
there are outliers of clay on the Spilsby Sandstone, which at
Hundleby, and again at Marden Hill near East Keal, have been
extensively dug for brick-making. These clays have always been
mapped and recognized as part of the Tealby Clay, and must indeed
originally have been conterminous with that deposit; yet they
contain B. lateralis and its accompanying fauna, from bottom to

* Quart. Journ. Geol, Soc, vol. xxxviii. (1882) p. 242.
? See note, p. 207,

204 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

top as far as exposed, and must therefore be considered along with
the Spilsby Sandstone and the Claxby Ironstone as forming, for
paleontological purposes, the ‘ Zone of Belemnites lateralis.’ The
sections afforded by these pits are as follows :—

Section at the western end of Hundleby Brickyard.
Feet.
Ferruginous gritty clay, partly indurated and nodular, with a
few obscure fossils ; rather like the Carstone in appearance. 3
SUL ECO MIL GY ACLany semen = cede catacs «des < cece cose ne sein veeas queer
Band of irregular, round, brown, ferruginous nodules. Am-
monites, cf. gravesiformis, ete.
Striped pale- and dark-blue gritty clay .............00: BR PA 5 9)
Band of large pale-brown nodules.
Blue pyritous clay with pale sandy streaks, and flat pyritous
nodules full of coarse grit. Belemnites lateralis; small
crushed ammonites; wood perforated by boring-shells, etc... 5

Section at the south-western corner of Marden Hill
(Hast Keal) Brickyard.
Feet.
Red clayey soil and drift, with fragments of chalk and flint.
about 3

Weathered banded clay, brown, pyritous, and silty, with slightly

ferruginous layers and sandy streaks, and a gritty seam at

DROMDASO Mss salseis waive na and oxiad ou dalatiaewogo 3ehee ae oS ae eRR Rema about 4
Silty blue clay with sandy streaks and ferruginous layers ...... 5
Fossiliferous seam, with Belemnites lateralis, small crushed

ammonites (Olcostephanus), and many small univalve and

bivalve shells.
Clay as above, rather more gritty, with coarse grit-grains in

flat pyritous nodules. JB. dateralis and other fossils as above,

ATI FLA COS as. 0 cle vs acs oni os as «s'acidw detain sedate ele pea ee eee eee slg
Floor of lumpy ferruginous stone, like coalescent nodules,

slightly gritty, and full of oolitic ferruginous grains. Many

casts of fossils, Ammonites (Olcostephanus), cf. gravesi-

formis, ete., Trigonia, Astarte, ete.

The fossils of these pits are practically identical. At Hundleby,
though the unworked condition of the section at the time of
my examination of it, in 1893 and again in 1895, was unfa-
vourable for collecting fossils in place, I found fragments of
Belemnates lateralis scattered in all parts of the pit, unmixed with
any other form of the genus. I found also clay-stone casts of the
deep umbilicus of ‘coronated’ ammonites akin to Olcostephanus
(Polyptychites) gravesiformis, Pavl. (= Ammonites Irius, d’Orb., of
Judd), exactly as they occur in bed D3 at Speeton, together with
some smaller specimens of the same group, O. (P.) cf. Keyserlingi
and cf. gravesiformis (which are evidently the forms referred in
the Geol. Surv. Mem. to A. speetonensis), and several brachiopods
and lamellibranchs present in the Claxby Ironstone.

At Marden Hill on my last visit the section was quite fresh
in one part of the pit, and here I obtained Belemnites lateralis in
the clay within 9 feet of the top, and at lower levels down to the
base of the pit, but found no trace of any other belemnite. Small

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 205

imperfectly-preserved ammonites, very similar to those which
occur abundantly in the ‘ Astarte-bed’ D 4 at Speeton, were rather
plentiful at one horizon in the clay, and also in the ferruginous stone
at the base of the pit, the species being the same as at Hundleby.

Most of the bivalves found in the other pit also occurred here;
and in a silty band in the clay about halfway from the top of the
section, along with some small crushed ammonites (Olcostephanz),
were numerous dwarf univalves and bivalves referable to Dentalium,
Cerithium (?), Pecten (a Spilsby Sandstone form), Isocardia (?),
Astarte cf. senecta, etc.

An important feature of both sections is the large admixture of
coarse sand with the clay. This occurs throughout in little dabs
and streaks, or in thin irregular seams tending to concentrate into
shallow cakes of irregular outline, or to be caught up in the con-
cretions of iron pyrites. In some places this sand is so coarse as
to be almost pebbly, and the quartz-grains have a smooth polished
surface, like the grains in the Spilsby Sandstone. Similar sandy clay
associated with the Spilsby Sandstone seems to have been met with
in the deep boring at Skegness, 11 miles farther east. I have not
found this gritty character in anything like the same degree in the
Tealby Clay anywhere along its main outcrop under the Chalk
escarpment.

From the Geol. Surv. Mem. (‘ East Lincolnshire,’ pp. 14 and 22)
we learn that the ferruginous stratum at the base of the Hundleby
pit rests directly upon the Spilsby Sandstone, and that a well was
sunk in it to a depth of 14 feet without reaching its base. The
rock forming the floor of the Marden Hill pit is mentioned as
being ‘ probably the same bed as that seen at Hundleby’; but
itappears to me not unlikely that it may represent one of the
higher nodular bands of the Hundleby section. The clay at Marden
is rather more gritty, while at Hundleby there are bands of ferru-
ginous concretions, in the clay above the base of the pit, which are
not present at Marden, and the general field-evidence suggests that
the Marden section is the higher.

In the Survey Memoir the Hundleby Ironstone is held to be the
southern equivalent of the Claxby Ironstone, and the overlying clay
is recognized as forming the base of the Tealby Clay. A list of the
fossils of the clay is given (op. cit. p. 142), consisting of 13 species,
with 9 further cases in which the genus only is determined. It is
remarked at the foot of this list that ‘this assemblage is also’
(i. e. like that of the underlying Ironstone) ‘eminently Neo-
comian.’ Belemnites lateralis, Ammonites speetonensis and A. Gower-
tanus (?) are the cephalopoda mentioned, and these by no means
establish the statement, while the remaining fossils, with the ex-
ception of one brachiopod, are all lamellibranchs of doubtful value
as determinatives in this case.

At any rate, these sandy clays all fall within the zone of
B. lateralis, and, as will presently be shown, their fauna is quite

' Geol. Surv. Mem. 1887, ‘ East Lincolnshire,’ p. 169, ; see also Quart. Journ.
Geol. Soc. vol. xlix. (1893) p. 472.

206 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

distinct from that of the main mass of the Tealby Clay. And since
we know that the Claxby Ironstone extends to the top of this
lateralis-zone, it follows that the clays in question cannot represent
a higher horizon than that deposit. These clays, with their accom-
panying bands of ironstone, occupy in fact the same position with
regard to the Spilsby Sandstone at the southern end of the Wolds
as the Claxby Ironstone farther north, and are equivalent in age.

We are thus brought face to face with an excellent example of
that divergence of results which is bound to present itself sooner
or later whenever the lithological and the paleontological characters
of a stratified series are independently traced out over an extended
area. .

It cannot be denied that throughout Lincolnshire the Spilsby
Sandstone and the Tealby Clay, and to some extent also the Claxby
Ironstone, form well-defined stratigraphical units, which must be
taken by the field geologist as the basis for his work in mapping
out the structure of the country. Yet the palzontological evidence
demonstrates that the boundaries of these continuous masses of like
material are not strictly isochronous lines, but have had a progres-
sive development.

It seems almost inevitable that in such cases the paleontologist
and the stratigraphist must fix each his own limits independently
of the other. The stratigraphist cannot well make use in the field
of a line which forsakes a strongly-defined lithological junction
to wander vaguely amidst a mass of uniform composition, wherein
he could scarcely follow it even were there continuous sections
in every direction. The paleontologist on the other hand is
equally compelled to repudiate boundaries obliquely traversing
time-limits and life-zones which he seeks above all things to
define.

If we could study the extension of the whole series in an easterly
direction, we should probably find this lateral change of lithological
character even still more strongly marked. Apparently towards that
quarter the various strata would merge into a clayey sequence.
such as we find at Speeton, as is indicated by the borings east of the
Wolds. At Willoughby the full thickness of the Spilsby Sandstone
was not proved, but the character of the stratum seems to have
become greatly modified, being no longer a clean grit but an
‘earthy sandstone’ and ‘ferruginous marlstone,* while in the
Skegness boring already referred to, the Sandstone which is about
50 feet thick in the neighbourhood of Spilsby, has thinned away to
19 feet, and is associated with clay both above and below; and
the overlying clays have thickened from about 70 to191 feet. The
presence at various horizons in the clay at Speeton of thin, imper-

1 A.J.Jukes-Browne, Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 467. In this
‘paper a somewhat different reading is given of the Skegness boring from that
in the Geol. Surv. Mem. (‘ East Lincolnshire,’ p. 168), and the thickness of the
Spilsby Sandstone (including in this term some clayey material) is stated to
be 26 feet. Ata boring near Driby, if the record is to be trusted, only 4 feet
of sand (Spilsby Sandstone) and 4 feet of ironstone (Claxby Ironstone ?) was
found between the Tealby Beds and the Kimeridge Clay (ibzd. p. 155),

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 207

sistent ferruginous stone-bands,’ probably indicates the final stages
of this lateral change. Such changes are of course among the
commonplaces of geology, and parallel examples might be adduced
from beds of almost every age at home and abroad. Dr. J. W.
Gregory has recently drawn attention to a striking example of
similar conditions in the Gault and Lower Greensand of the South-
east of England, and he, too, has pleaded the necessity for the
recognition of two independent scales, the lithological and the
chronological,—‘ not contradictory, but complementary, and each
must be retained for its special purpose.’ ’

f. The Tealby Clay.

The available information regarding the exact age of the Tealby
Clay along the major part of its course is very meagre, from the lack
of clear exposures, and from the perishable character of the fossils
which are largely pyritous.

Most of the sections have already been referred to, and will need
very little further description. In the slope above the mine-build-
ings near Acre House the clays are exposed in a water-runnel and
at a few other places in the same vicinity, including the slip-section
already given (p. 203). The fossils noticed here are Belemnites
jaculum in tolerable abundance, Hxoqgyra sinuata (the large ‘ Lower
Greensand ’ form, which is common in the beds C 4 and 5 at Speeton
and differs from the allied shell occurring in the zone of Belemnites
lateralis), Nucula sp. and several other small bivalves in a poor
state of preservation, and some crustacean remains (Meyeria cf.
falcifera, Phill.). In this locality the thickness of the Tealby Clay
in the mine-shaft is stated at 40 feet.* In character it is a rather
pale striped blue clay of fine texture, with a few small oval nodules
of pale brown exterior and darker interior, which frequently contain
fragments of crustaceans. This deposit, in its close lithological
correspondence with its equivalent horizon at Speeton, stands alone
among the members of the Lincolnshire succession.

Southward from Nettleton Hill I found no place, where the fauna
of the clay could be studied, nearer than the pit at Donnington
Station, mentioned on a previous page. ‘The only other fossils
which I have found here besides Belemnites jaculum (which is
abundant) and Olcostephanus (Simbirskites) wmbonatus, Lahus., are
Exogyra sinuata (as above), Pecten sp., and other ill- preserved shells,
Serpula sp., and Meyeria cf. falcifera (abundant). In the Geol. Surv.
Mem., Ammonites speetonensis vars. venustus and concinnus *, Crioceras
Duvalu, and Perna Mulleti are also recorded from this place.

1 See ‘Subdivisions of the Speeton Clay,’ Quart. Journ. Geol. Soc. vol. xlv.
(1889) p. 594, and sections, figs. 4 & 5.

2 «On a Collection of Fossils from the Lower Greensand of Great Chart, in
Kent,’ Geol. Mag. 1895, p. 103.

3 J. W. Judd, Quart. Journ. Geol. Soc. vol. xxvi. (1870) p. 331.

4 The specimens under this name are very near to, if not identical with, the
form from my Speeton collection figured by Pavlow in ‘ Argiles de Speeton,’
pl. xviii. (xi.) fig. 1, as Olcostephanus (Simbirskites) Payeri, Toula, a species
founded on specimens from the Island of Kuhn, off the coast of Greenland (sea
Toula, ‘Geologie Ost-Gronlands,’ p. 498).

208 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

After this there is again a space of 8 miles in which, though the
clay can be seen in places, no opportunity is afforded for obtaining
fossils from it. Some old clay-pits about a mile to the eastward of
Tetford are then reached, from the weathering slopes of which I have
collected fragments of Belemnites gaculum in numbers, along with
Meyeria ornata, Phill., Exogyra sinuata (as before), Pecten (probably
cinctus), Isocardia angulata, Phill.,and Trochus pulcherrimus? Fine
selenite-crystals up to 14 inch in diameter are also abundant.
In general character the clay resembles that of Donnington and
Acre House. The above-mentioned fossils are all Speeton species,
and indicate that the horizon of this pit likewise is about midway in
the ‘ Zone of Belemnites yaculum.’ Yet the field-evidence shows that
the pit cannot be far above the base of the Tealby Clay, which seems
here to rest directly on the Spilsby Sandstone, the Claxby Jron-
stone apparently not being represented in this neighbourhood; and
the absence of the lower part of the ‘ Zone of Belemnites jaculum’
is thus once more indicated.

About 12 mile farther south-east I found Belemnites jaculum
washed out of the clay by a little stream running down the
hill at South Ormsby; but in the remaining 6 miles between
this locality and the southern termination of the Wolds at Spilsby
no further fossil evidence was forthcoming. In the outliers to the
westward of Spilsby, as has already been shown, the clays are of a
different age and type.

So far therefore as the Tealby Clay under the Chalk escarpment

can be examined, one stage only is represented, this being the middle
and perhaps the upper portion of the ‘ Zone of Belemnites gaculum’
(beds C2 or 3 to C5 or 6) of the Speeton Clay ; while the rich
fauna of the Ammonites noricus (regalis)-beds, which tenants 20 to
30 feet of clay in the lower part of this zone in Yorkshire, is not in
Lincolnshire revealed in any visible section, except so far as its
lowermost portion may be condensed in the uppermost clayey layer
of the Claxby and Donnington Ironstone.

But the great expansion of these clays towards the east, which
is a marked feature along the outcrop,’ and is still better revealed
in well-borings east of the Wolds at Alford, Willoughby, and
Skegness, indicates that, as already hinted, the deposit almost
certainly encroaches on both lower and higher zones in its prolong-
ation in that direction, and gradually replaces, in part or wholly, the
Spilsby Sandstone, the Claxby Tronstone, and the Tealby Limestone.
Its greater thickness is therefore probably due, not so much to the
thickening of the individual beds exposed at the outcrop, as to
the incoming of higher and lower argillaceous deposits slightly
different in lithological character and almost entirely different in
fauna.

Under these conditions we may safely surmise that eastward,
under the bed of the North Sea, the whole series merges into the

1 A. Strahan, Quart. Journ. Geol. Soc. vol. xlii. (1886) p. 488, and Geol. Sury.
Mem. 1888, ‘ Country around Lincoln,’ p. 96.

Vol. 52. ] IN YORKSHIRE AND LINCOLNSHIRE. 209

clayey sequence whose fringe is so conveniently revealed to us in the
coast-section at Speeton. Westward and southward, on the other
hand, it is very probable that the clays diminish, until the sands of
the underlying and overlying horizons unite and become indistin-
guishable.*

g. The Tealby Limestone (with the Upper Clay and
‘ Roach’).

I have not devoted so much time in the field to the strata
overlying the Tealby Clay as to those below that horizon, mainly
because while their general correlation is readily arrived at, a more
detailed comparison is rendered difficult by the still incomplete state
of our information regarding the upper division of the Speeton Clay.
Sufficient has been done, however, to demonstrate the relationship of
these rocks to the rest of the section, and to improve our knowledge
of their paleontology.

The hard calcareous bands with variable clay partings capping
the Tealby Clay, known as the ‘ Greystone’ or ‘'Tealby Limestone,’
form a prominent feature in the stratigraphy between Caistor and
Donnington, but are not definitely recognizable farther northward
or southward, nor have any continuous hard beds been revealed
at this horizon by the borings east of the Wolds. These facts,
together with the thin and irregular character of the courses and
the extent to which they are interbedded with, and in places
overlain by, shaly or clayey material, suggest that the limestone is
merely a locally calcareous modification of the upper portion of the
Tealby Clay. It is therefore rather surprising to find how greatly
the fauna differs from the known fauna of the Tealby Clay.

The limestone is best exposed in the numerous shallow pits be-
tween Normanby and North Willingham.’ Fossils are everywhere
present, but are not easy to extract ; and there seems to be some
difference in the species occurring in the different sections. The
belemnites again supply the most definite information. They are
frequently abundant, especially in the shaly partings, and are
all recognizable as well-known Speeton forms occurring in the ‘ Zone
of Belemnites brunsvicensis’ (B), namely, B. brunsvicensis, Stromb.,
B. speetonensis, Pavl., and B. Jasikowz, Lahus. No other species
have been found, and the record of B. lateralis from this horizon
by Prof. Judd and the Geological Survey was evidently due to the
confusion in the determination mentioned on a previous page.

Ammonites are rarer, the only serviceable specimens that I have
myself discovered being found in the higher pit on the north side of
the high road, east of North Willingham. These belong to the large

1 For the discussion of this point see A. Strahan, ‘On the Lincolnshire Car-
stone, Quart. Journ. Geol. Soc. vol. xlii. (1886) p. 491.
2 In this locality the limestone-bands occasionally enfold phosphatic and
yritous concretions, just as the large limestone-nodules of the ‘ Compound-
Nodule Band,’ D1, of Speeton enclose similar earlier concretions,

210 MR. G@, W. LAMPLUGH ON THE SPEETON SERIES [May 1806,

clypeiform species usually recorded as Ammonites clypetformis,
d’Orb.,' examples of which under this name are preserved in most of
our public collections of Lincolnshire fossils ; but I do not think that
this determination can be sustained. It is only in its adult stages
that the ammonite assumes its sharply-keeled discoidal form and
smooth sides, since the inner whorls present a rounded back and a
few continuous ribs, the fossil at this stage being very near to, if
not identical with, Ammonites Carteron, d’Orb. It is possible that
the young forms of this ammonite may occur at Speeton, but I have
not seen an adult specimen there.

Among the other and more abundant fossils are Pecten (several
species), Exogyra sinuata (the Tealby Clay form), Ostrea ‘frons,
Park. (plentiful here, but very rare at Speeton), Lima, Pholadomya,
and many other lamellibranchs, with some brachiopods, etc. Several
of the above occur at the equivalent horizon at Speeton, but their
relative abundance in the two areas is very different.

Pecten cinctus is often very plentiful and of large dimensions,
but I think that it displays characters of varietal, or even of specific
value, differentiating it from the similar fossil of the Claxby
Ironstone and Spilsby Sandstone. In the last-mentioned stratum
the dwarfed representatives of the species can scarcely be distin-
guished from P. lamellosus, Sow., of the Portlandian, and when the
fossil is studied throughout its extended range it will probably
furnish the paleontologist with another illustration of a slowly-
changing species, with all the usual difficulties, to which I suppose
that he will in time become accustomed. Under present conditions
the species is, as I pointed out in my former paper, of very little value
as a zonal fossil.

The evidence of the fauna, then, suffices to enable us to recognize |
in the Tealby Limestone, as developed in the above-mentioned area,
some portion of the ‘Zone of Bel. brunsvicensis’ (B) of the Speeton
section ; and the presence in Yorkshire in the clays of this horizon
of a considerable amount of calcareous matter, which takes the form
of bands of thickly-set septarian nodules of large size (‘ Cement
Beds’ of Judd), indicates that the deposition of more or less
calcareous sediment was common to both districts at this stage.

- The evidence is insufficient to demonstrate exactly how much of
this extensive zone is represented by the Tealby Limestone, but it
seems probable that if we could have complete sections we should
find Belemnites brunsvicensis extending slightly below the base of
the limestone in most localities, and also stretching upward at
least as far as the lowest part of the Carstone.

Regarding the ‘ Roach Ironstone and Clay’ which underlie the
Carstone farther south, and are by the Geological Survey considered
to be the southerly equivalents of the Tealby Limestone, I have no
new information whatever to bring forward. Such scanty exposures
of these deposits as I could find were unfossiliterous, and therefore
practically useless for my purpose.

1 J. W. Judd, Quart. Journ. Geol. Soc. vol. xxiv. (1868) p. 246 ; list repro-
duced in Geol. Surv. Mem. 1888, ‘Country around Lincoln,’ p. 103.

Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. , 211

h. The Carstone.

The lithological characters and stratigraphical relations of the
pebbly ferruginous sand which in Lincolnshire overlies the deposits
above described, and extends upward to the Red Chalk, have been
carefully set forth in the Survey Memoirs* and in Mr. A. Strahan’s
excellent paper on the subject in this Journal.” Exceptin the layer
immediately below the Red Chalk, where Belemnites minimus and
Terebratula biplicata are found, fossils are of very rare occurrence
in it. Such as have been discovered are contained in eroded
phosphatic nodules, and are supposed to have been derived from
lower strata which have been destroyed.

The species recorded * are: Ammonites speetonensis?; A. plicom-
phalus? and Lucina ? from a nodule-bed at its base near Otby; and
A. Deshayesu, A. triplex, Requenia?, Astarte, Corbula, Modiola,
Myacites, Pholadomya, Cyprina, and Teredo, from Claxby.

Not having myself succeeded in finding any of these fossils in the
deposit, 1 have been unable to investigate their mode of occurrence
and the character of the supposed ‘ pebbles’ with which they are
associated, and therefore am not in a position to discuss their
origin. But from the nature of the list and the general features of
the nodules in the stratum, I am inclined to consider their derivative
nature not proven. At any rate, Ammonites Deshayesti is not far
from its proper horizon, and, as already stated (p. 198), I am satisfied
that where this species occurs in the Carstone at Hunstanton it is
not derivative, but in place. The other ammonites mentioned, being
all uncertain species, are of slight account in the discussion, while
the remaining determinations of the list are too incomplete to afford
any information.

As regards the stratigraphical relations of the deposit, I can cor-
roborate Mr. Strahan’s account of its upward passage into the Red
Chalk, and the presence of Belemnites minimus in it just below the
junction, In the southern part of its outcrop the Carstone has a
thickness of about 40 feet, but northward it thins away, until in the
last sections seen before reaching the Humber it remains only as a
pebbly base to the Red Chalk. Both phenomena are exactly repro-
duced, as shown in an earlier part of this paper, by the ferruginous
sands exposed in a few places along the western edge of the Yorkshire
Wolds, which are no doubt the northern equivalents of the Carstone.
And as it has been also shown that these Yorkshire sands can be
correlated with much probability with the ‘ Passage-marls with
Belemnites minimus’ (A) of Speeton and Knapton (which, it may
be noted, contain at the first-mentioned place ‘lydites’ and other
small gritty particles), it follows that the same correlation must be

1 «Country around Lincoln,’ pp. 105 e¢ segg.; ‘East Lincolnshire,’ pp. 23
et seqq.

2 “On the Lincolnshire Oarstone, Quart. Journ. Geol. Soc. vol. xlii. (1886)
p- 486.

* Ibid. p. 488; the Claxby list was supplied to Mr. Strahan by Mr. H-
Keeping. d :
Q.J.G.8. No. 206. Q

212 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1806,

applied to the Lincolnshire Carstone. But if Hoplites Deshayesia be
in place in Lincolnshire as in Norfolk, it would appear that where
the Carstone is fully developed its lower portion must lie within
the ‘Zone of Belemnites brunsvicensis, in which event the interval
between it and the Tealby Limestone cannot be great.

Indeed under any circumstances, if I am right in thinking that
no break exists at Speeton between the ‘ Passage-marls ’ and the
clays containing B. brunsvicensis, Hoplites Deshayesit, and Amaltheus
bicurvatus, any unconformability which may exist at the base of
the Carstone, as supposed by Mr. Strahan, must possess a relatively
small time-value where that deposit overlies the Tealby Limestone
Series, since on comparison of this part of the Lincolnshire sequence
with that of Speeton there is seen to be little or nothing lacking.

At the upper boundary of the deposit it is very probable that
there may be in some degree a lateral as well as a vertical passage
into the Red Chalk. ‘That the accumulation of sand in the shal-
lower or more exposed areas probably continued for some little time
after the deposition of the chalky sediment had commenced in
adjacent regions is, I think, directly suggested by the evidence
made known to us by Mr. W. Hill in his careful study of the lower
beds of the Upper Cretaceous rocks.1 With the Red Chalk com-
menced that period of slow depression, which in its later stages
brought back once more an uniformity of conditions over the
eastern part of England which had not existed since Kimeridgian
times. This depression swept away the more local influences which
had hitherto prevailed in South Yorkshire and North Lincolnshire,
where a belt of country had been slowly brought up within reach
of the denuding agencies and gradually planed down. South and
east of the elevated area, even where the marine conditions were
continuous, the proximity of land and the gradual change in its
outline affected from time to time the factors which govern the
accumulation of sediments, so that in Mid-Lincolnshire the
deposits of this period are marked by their local and changeful
characters.

V. STATEMENT OF THE CoRRELATION.

The result of this investigation is to show that in Lincolnshire,
as in Yorkshire, the various species of belemnites present in the
rocks afford the most natural and convenient means for classifying
the strata ; but that the well-defined zones which they form do not
always coincide with the lithological divisions.

Of these zones, that of Belemnites lateralis appears to be quite as
fully represented in Lincolnshire as at Speeton. The ‘Zone of
Belemnites jaculum, which occupies so large a proportion of the
Speeton Clay, is in most of the Lincolnshire sections condensed into
narrow limits, and may be in part unrepresented.

The ‘ Zone of Belemnites brunsvicensis’ is well exhibited, but from
the unfossiliferous character of some of the sediments and the lack of

1 Quart. Journ. Geol, Soc. vol, xliv. (1888) p. 320.

IN YORKSHIRE AND LINCOLNSHIRE.

ETON
IFF.

South-
ward.

ei —| : :

—— oe ow ‘

ai

oe r= ar Ss

e

e_ eS
— =e = ee oe ee

Nettleton Hill,
Lincolnshire.

Ta m

‘CARSTONE’

Rie Le eT | eee

’
,
,
4
,

. aN ety ros
== ese wee cme we Cw et et eS Se

ty |
RED Eilat

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[To face p. 212.

Southern part
of Lincolnshire
Wolds.

ageal Gi (hr)
REQ ICHALI
th wel “qn I

aS) | Se @™ Gia SS

NSS et wwe waa Bat

-CARSTONE.

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PP’ ie Y_

rant a ie is
and “ReachtL
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“+ Iron'stone! °.
|

STEACBY=CEAY*-
-of=Hundteby-and

Quart. Journ. Geol, Soc. Vol. LII.

[To face p. 212.

DsacRaM sHowINe THE CoRRELATION oF THE SPEETON SERIES IN YORKSHIRE AND LINCOLNSHIRE.

Fossiz Zonzs.

A. Zone
of

Bel. minimus, List.

B. Zone
of
Bel. brunsvicensis,
Stromb.
(e, Zone
of

Bel. jaculum, Phill.

D. Zone
of

Bel. lateralis, Phill.

7

F. Shales
with d
Bel. Owenii, ete.

peuHes bads.

WANTING

WANTING

WANTING

(USUALLY)
WANTING

Western edge
of Yorkshire
Wolds.

K __West- | SPEETON | soutn-, | Nettleton Hill, Southern part
Eo ward. CLIFF. ward. Lincolnshire. of * caluahire
olds.

4M Mee

ay

nl a w

“CARST.QNE,

_es

eee eee

WANTING ?

Vol. 52. ] IN YORKSHIRE AND LINCOLNSHIRE. . 213

clear sections, only the broader features of its relationship can be
demonstrated.

In both areas the uppermost beds of the series pass upward into
the Red Chalk.

The correlation of the typical sections of each district is illustrated

in the diagram facing the opposite page.

VI. Tue Acs oF THE BELEMNITES LATERALIS BeEps.

The definite purpose of my paper was to bring out anew, and to
place on a more satisfactory basis, the relationship of the strata
underlying the Chalk in Yorkshire and Lincolnshire, and I venture
to hope that in the preceding pages this has been accomplished. As
for the broader issues to which this work gives rise, I think they
may for the most part await with advantage the accumulation of
fuller and more accurate information on many points. In England
there is still much to be done, both in the study of the palzonto-
logical material already collected, and in the re-examination, in the
light of the new evidence, of the region lying to the southward of
that herein discussed. In the Eastern Midlands at least some
portion of the fauna of the Speeton Series (including Belemmnites
(lateralis) subquadratus) is preserved in some of the phosphatic-
nodule beds, but whether in an original or derivative form is still
uncertain. In several regions abroad also, and especially in Germany,
the information which we possess regarding the corresponding strata
is at present conflicting and insufficient, and will undoubtedly be
considerably affected by researches which are now in progress. I
had indeed hoped that my esteemed friend Prof. Pavlow would have
been able to lay before the Society on this occasion a résumé of the
-available facts respecting the Continental equivalents of the series.
But Prof. Pavlow has at the last moment, from physical indis-
position, found it impossible to complete his notes in time. We
may hope, however, that he will shortly be able to bring forward
his valuable contribution on the subject. Meanwhile I think that
a brief recapitulation of the work already published, bearing on the
disputed question of the age of the Zone of Belemnites lateralis, will
form a fitting conclusion to this paper.

Leckenby seems to have been the first definitely to formulate
the view that the lowest part of the Speeton Clay should be classed
as Jurassic, basing his opinion mainly on the occurrence therein ot
coronated ammonites of the Gravesianus-type.” These ammonites
were afterwards supposed by Prof. Judd to have been obtained
from beds capping the Upper Kimeridge shale, but below the clays
with Belemnites lateralis. In my former paper, however, I was

1 [While this paper was passing through the press, the communication
of Prof. Pavlow above referred to, ‘ On the Classification of the Strata between
the Kimeridgian and Aptian,’ was read, and its publication may be looked for

in a subsequent number of the Journal.— April 22nd, 1896.]
2 See note by J. Leckenby in Dr. T. Wright’s Monogr. ‘ Brit. Cret. Echinod..,'

Pal. Soc. vol. xxi. pt. i. p. 9.
3 “On the Speeton Clay,’ Quart. Journ. Geol. Soc. vol. xxiv. (1868) p. 28.
2

Q

214 MR. G. W. LAMPLUGH ON THE SPEETON SERIES [May 1896,.

able to prove that the true horizon of these fossils was the upper part
of the Zone of Belemnites lateralis. Hence, if these ammonites were
sufficient to demonstrate the Portlandian age of the rocks containing:
them, the line between Jurassic and Cretaceous in the Speeton:
section must, I urged, be drawn at the top of this zone, as Leckenby
proposed, and not at its base, as Prof. Judd had suggested.

Meanwhile the subject had been attacked from an entirely dif-
ferent standpoint by the Russian geologists M. Serge Nikitin (of
the Russian Geological Survey) and Prof. A. Pavlow (Moscow
University), who had attended the meeting of the International Geo-
logical Congress in London in 1888, and had taken the opportunity
then afforded of studying the Speeton section and its fauna upon
the spot. These gentlemen soon afterwards published independent
readings of the section and its correlation,’ differing in some im--
portant points, but agreeing in recognizing in the Zone of Belemnites
lateralis the equivalent of the ‘Upper Volga Beds’ of Central
Russia and the Purbeck of the South of England. Nikitin however
considered that’ the ammonites afforded no evidence of the Jurassic
age of the beds, since they had been incorrectly determined, and
belonged in reality to species recognized as Neocomian in Germany.”
He was thereby confirmed in his previously-expressed opinion that
the Upper and Lower Volga Beds of Russia (and presumably also
their English equivalents) should be regarded neither as Jurassic:
nor Cretaceous, but strictly as passage-beds between these systems...
Pavlow, on the other hand, thought that a stricter definition was
possible, especially as he regarded the Zone of Belemnites lateralis as
equivalent not only to the Purbeck, but also to the Portland Stone:
ot the South of England.

In a later memoir ® (to which I had the honour of contributing a:
chapter respecting the stratigraphy of the deposits in the North
of England) Prof. Pavlow, continuing to work on the same
general lines, extends his study of the subject to embrace the whole
of the North European area, and shows that the cephalopoda of
these rocks confirm in most points his former conclusions. He finds
a certain amount of difference between the fauna of the upper and
the lower portions of the Zone of Belemmites lateralis, which enables
him to divide it into two parts characterized by different types:
of ammonites (in the same manner as the Zone of B. jaculum is

1 §. Nikitin, ‘Quelques Excursions dans les Musées et dans les Terrains
Mésozoiques de |’ Kurope occidentale, Bull. Soc. Belge de Géologie, vol. iii-.
Mém. pp. 29-58 (1889) ; A. Pavylow, ‘ Etudes sur le Jurassique supérieur et
le Crétacé inférieur,’ Bull. Soe. Imp. Naturalistes de Moscou,’ n.s. vol. iii.
(1889) p. 61.

? The German evidence becomes here of extreme importance, and I am very.
glad to learn that the whole question is now being carefully re-studied in that
country. Ifthe German equivalent of the zone of Belemnites lateralis has been
considered Neocomian only on the strength of the old Speeton correlation, no
argument could be safely deduced from this quarter. But from its geographical
position the succession in Germany will probably eventually be found comparable
with several surrounding areas, and thus the linking together of the outlying,
regions will be more securely done than is at present possible.

° * Argiles de Speeton,’ Moscow, 1891-1892.

"Vol. 52.7] IN YORKSHIRE AND LINCOLNSHIRE. 215

divided), the lower being tenanted by Olcostephanus (Craspedites)
subditus and allies, and the upper by O. (Polyptychites) gravesiformis
-and allies. These together form the ‘série Speetono-russe’ (p. 174),
which he shows to be equivalent to the Upper Portlandian (Purbeck
and Portland Stone) of the South of England, and he proposed to
designate these rocks the ‘sous-étage Aquilonien’ (p. 192). He
then discusses exhaustively the correlation of this ‘ Aquilonian sub-
‘stage’ throughout Europe, and shows that everywhere in Southern
as well as in Northern Europe the equivalents of this sub-stage
underlie the ‘ étage Néocomien inférieur,’ which upon various con-
-siderations is declared the true base of the Lower Cretaceous system.
He further urges in favour of this grouping that it agrees best with
‘the older definitions and traditions of the science, and concludes his
argument thus :—‘ Si nous replacons l’ancienne limite entre les
deux systémes nous nous privons d’une limite trés nette, paléonto-
logiquement trés bien définie, et qui, grace a la transgression
remarquable de la faune méridionale vers le Nord, peut-étre
observée dans une vaste région, circonstance qui nous fait considérer
cette limite comme trés heureusement choisie par les coryphées de
la science et comme trés précieuse au point de vue de la strati-
graphie comparée. Cette limite a été tracée par la nature méme
omme une limite ayant fixé ’époque d’un événement géologique
remarquable, savoir la disparition d’une partie considérable du con-
tinent portlandien et le commencement de la migration de la faune
méridionale vers le Nord, et réciproquement peut-étre.’ (‘ Argiles
de Speeton,’ sep. cop. p. 199.)

But to establish this classification it became necessary to carry
down into the Jurassic system not only the whole of the Berriasien
. of South-eastern France, but also the so-called Wealden and the
Hils Conglomerate of North-western Germany, and in doing this
Pavlow is at variance with the opinions of several geologists of the
Continent, so that the subject must be considered as still under
discussion, Indeed, in a later paper, ‘On the Mesozoic. Rocks of
the province of Riasan, Russia’ (Moscow, 1894),’ if I rightly
understand the brief final résumé in French, Prof. Pavlow seems
inclined to grant that recent discoveries have shown that the
‘ Petchorian sub-stage,’ capping the ‘ Aquilonian,’ with Olcostephanus
-stenomphalus in the lower part and Polyptychites Keyserlingt in the
upper portion, may in that region correspond to the Lower Neocomian
of Central Europe. In his forthcoming notes on the subject Prof.
Pavlow will no doubt discuss this new evidence, and show its exact
bearing on the question at issue.

So far as the classification of the English strata is concerned, it
must, I think, be admitted that the limit of the Lower Cretaceous
and Jurassic systems is more or Jess arbitrary and conventional,
often without reality in the field, and is therefore to be treated on
a basis of general convenience and historical priority. And this

* Scient. Mem. (Utcheniya Zapiski) Imp. Univers. Moscow, vol. xi. p. 1.
aa H. B. Woodward, Geol. Surv. Mem. ‘ Jurassic Rocks of Britain,’ vol. v.

216 MR, G, W. LAMPLUGH ON THE SPEETON SERIES [May 1896,

state of affairs prevails, as the above discussion has indicated, not
in England only, but throughout the greater part of Europe,
and also in North America. Under such conditions there must
necessarily be much discussion and interchange of views before
a boundary of general application can be agreed upon. Nor is this
at all attainable except by some sacrifice in matters of local con-
venience.

Thus, in the North of England there is no doubt that in spite of
the early-recognized and oft-discussed Jurassic affinities of the
Spilsby Sandstone fauna,! the field-geologist working independently
in that district would find the base of that deposit to afford by far the
most suitable line of demarcation between the systems. It is a
strongly-defined horizon, marking the termination of a period of
quiet and uniform sedimentation over the whole region, while above
it, owing to more local and less stable conditions, the character of
the accumulation frequently alters horizontally as well as vertically,
thereby rendering the tracing-out of a synchronal line a matter of
extreme difficulty. Yet it seems inevitable that, in spite of its con-
venience, this line will have to be abandoned whenever the wider
bearings of the stratigraphy of the region are in question, unless
we are prepared to advocate extensive alterations in other areas to
suit it. If, on the other hand, we take the upper boundary of the
lateralis-zone as our line of division, we find that though in York-
shire, as Leckenby pointed out, this horizon is lithologically well
defined, in Lincolnshire, as already shown, in the southern part of
its course it is purely paleontological and scarcely traceable on the
ground.

The division of the Zone of Belemnites lateralis into two portions.
by means of the ammonites, as proposed by Pavlow, suggests the .
possibility of an alternative course, by which the lower part with
Ammonites subditus, corresponding to the major portion of the Spilsby
Sandstone and presumably to Beds D 5 to D8 of Speeton, might
be separated from the rest of the zone, in which occur the ‘ gravesi-
form’ ammonites, and the one classed as Jurassic and the other as-
Cretaceous. [This scheme is powerfully advocated by Prof. Pavlow
in his recent contribution to the Society.] But while this plan
would possibly satisfy some of the objections which have been raised
to the inclusion of the whole zone in the Jurassic, it appears to
me that the life-forms other than the cephalopoda common to the
two parts of the zone will, when fully worked out, be found so:
numerous that a line drawn at this horizon would in England be
both paleontologically and stratigraphically weak, withous serving”
the general European convenience better than before.

1 Prof. H. G. Seeley, in the discussion on J. F. Blake’s ‘ Portland Rocks of
England, Quart. Journ. Geol. Soc. vol. xxxvi. (1880) p. 236, and in several
earlier discussions on similar subjects.

Mr. G. Sharman, in Geol. Surv. Mem. 1887, ‘East Lincolnshire, p. 141,.
in discu:sing the fossils, remarks:—-‘It is tolerably evident, therefore, that
these calcareous concretions (of the Spilsby Sandstone) occupy a lower horizon
han any Neocomian beds hitherto described, and, in so far as palxontological-
evidence goes, seem to occupy an intermediate position between the lowest.
Neocomian and the uppermost Oolites.’

Vol. 52. ] IN YORKSHIRE AND LINCOLNSHIRE. 217

However, where so much uncertainty still exists, it appears to
me that, pending the accumulation of further evidence, we shall
scarcely be justified in pronouncing on one side or the other a final
decision in this matter. Even with regard to the rocks of this age in
the South of England, on the classification of which the whole of this
discussion hinges, there is still much obscurity. It seems now to be
very generally acknowledged that there is a passage from Purbeck to
Wealden where both are fully developed’; and recently even the
strength of the evidence on which the Wealden itself is classed as
Cretaceous has been challenged, and the chief elements of its fauna
declared by several authorities to be Jurassic rather than Cretaceous
in their affinities.”

It appears, in short, to be the fact that while over Western Europe
there is usually a distinct stratigraphical break at the base of the
Upper Cretaceous, as Mr. Strahan and others have frequently
pointed out,* the base of the Lower Cretaceous, as at present
recognized, whether the sequence be freshwater or marine, presents
no such break, but a more or less gradual passage both in character
of deposit and in fauna. Under such conditions it is mainly a
question of general convenience what particular horizon shall be
taken as the boundary of the systems, and the essential determi-
native must rest in the agreement of competent opinion.

VII. Conctupine Summary,

The leading conclusions of this paper may be epitomized as
follows :—

|. Further work on the Speeton section, while extending our know-
ledge of the palzontological details, has fully sustained the
results of the author’s previous investigations.
2. The evidence at present available is insufficient to demonstrate
7 the exact conditions which bring about the rapid attenuation
and final disappearance of the Speeton Series in a westerly
direction in Yorkshire. Contrary to the accepted view, how-
ever, the lower zones are probably the first to die out, and
are overstepped or overlapped westward by the higher divisions,
since at Knapton, 14 miles inland, only the upper zones of
the coast-section can be proved to occur, as shown by the
presence of the marls with Belemnites minimus passing upward
into the Red Chalk, and by the fossils in the old collections,
including Hoplites Deshayesit, under the name of Ammonites
knaptonensis, Bean MS., and a few others of the same zone.

1 See H. B. Woodward in Mem. Geol. Surv. ‘Jurassic Rocks of Britain,’
vol. v. Pp. 3 and 243 et segg. (with good bibliography).

2 0. C. Marsh, Geol. Mag. 1896, p. 8; [also in ‘ Nature,’ vol. liii. (1896),
p. 436, as regards the reptiles; A. S. Woodward, Geol. Mag. 1896, p. 70, as
regards the fishes; and A. O. Seward, in ‘Nature,’ vol. liii. (1896) p. 462, as
regards the plants].

3 See, among others, A. Strahan’s recent paper ‘ On Overthrusts of Tertiary
date in Dorset,’ Quart. Journ. Geol. Soc. vol. li. (1895) p. 561.

218 MR. G. W. LAMPLUGH ON THE SPEETON sERIES [May 1896,

3. The ferruginous sands which occur locally beneath the Red Chalk
on the western edge of the Yorkshire Wolds are recognized as
agreeing in all respects with the Lincolnshire Carstone, and
where absent are to some extent represented by a pebbly base
to the Red Chalk, as in Lincolnshire. In both counties Mr. A.
Strahan’s conclusions as to the relations of the Carstone to the
Red Chalk are confirmed.

4, In Mid-Lincolnshire all the paleontological zones of the Speeton
Series are identified and traced ; and though their lithological
aspect is greatly modified, and is accompanied by a corre-
sponding modification of their fauna, the presence of the
leading zonal types of the cephalopoda readily establishes the
general correlation proposed by Prof. Pavlow and the author,
which differs in many respects from that adopted by previous
investigators.

5. In Lincolnshire, in at least one instance, the synchronal boundary,
as indicated by the limits of a paleontological zone, is shown
not to pursue the same stratigraphical horizon throughout its
course, proving that sediments of different character were accu-
mulated simultaneously in comparative proximity to each other.
The inherent divergence between the stratigraphical and pale-
ontological methods in geology is thus once more illustrated.

6. The derivative character of the band of phosphatic nodules at
the base of the Spilsby Sandstone is stated to be very doubtful ;
and the fossils of these so-called ‘pebbles,’ as of the corresponding
horizon at Speeton, are considered as probably representing an
original fauna, poorly preserved in nodules formed during a
temporary pause in the sedimentation.

7. It is shown that the ‘Zone of Belemnites lateralis’ bridges
over the space between undoubtedly Jurassic and undoubtedly
Lower Cretaceous Strata; but if the accepted classification of
other areas is to be upheld, it appears to be necessary that the
division between the systems should be placed high enough to
include this zone, or at least the greater part of it, in the
Jurassic, in spite of the local inconvenience of this arrangement.

Discussion.

The Prestpent said that it was hardly possible, when mapping in
the field, to do more than follow those petrological changes in the
character of beds over any given area which are patent to the
observer. The point discussed by the Author is that the life-line
- does not follow the line of the same sedimentation, but life-forms

may transgress, and do transgress, over sediments of different cha-
racter when they happen to be accumulated at the same time. — It
is hoped, however, that the case propounded by the Author is
exceptional, and that, as a rule, the sediments and the fossils
follow one another on the same lines.

Prof. Jupp congratulated the Society upon the valuable details
now communicated by the Author, and on the important work on

Vol. 52.] - IN YORKSHIRE AND LINCOLNSHIRE. 219

the fossils which had been done by him and Prof. Pavlow. He
thought that the admissions of the Author, however, pointed
to the desirability of the use of ammonite-zones in preference
‘to those based on belemnites. He also demurred to the excessive
importance attached to minute points of palzontological evidence
when seeming to be in conflict with the stratigraphical evidence.

Mr. SrraHan was prepared to find the paleontological and strati-
graphical grouping of these rocks slightly at variance. He had
pointed out some years ago that the Spilsby Sandstone became finer
in grain and was partly replaced by clay eastwards. Northwards,
towards Speeton, the same change took place, and no doubt the
Author was correct in attributing a portion of the clay at Hundleby
to that subdivision—on paleontological grounds. At the same time,
iit was inexpedient to draw any other line on the map than that
which had been taken. The separation of Jurassic from Neocomian
in Lincolnshire was based on stratigraphical considerations. A
glance at the map showed that the Neocomian group followed the
Upper Cretaceous through much of its range across Lincolnshire and
Yorkshire ; and though the great overlap took place at the base of the
Upper Cretaceous, yet there was also an unconformity at the base of
the Neocomian. So far as the North-east of England was con-
cerned, no other division between Jurassic and Neocomian than that
adopted by the Geological Survey was possible ; had a local name
been used in preference to the imported term ‘ Neocomian,’ much
confusion would have been avoided.

He had always regarded the nodule-bed in the Spilsby Sandstone
as a true conglomerate—a natural accompaniment of the uncon-
formity referred to. The nodules are clustered in a thin band
at the base of the rock ; they differ in their mineralization from the
indigenous fauna ; the recognizable forms resemble Kimeridge Clay
as much as they do Neocomian forms; the nodules show every
degree of wear and tear, and are rounded as though by rolling, and
not pitted as they would be by corrosion, nor have they attached to
them any of the original shell, nor any adherent organisms. He did
not argue that they had been derived from beds now underlying the
‘Spilsby Sandstone, but from strata that had been washed away.
The same arguments were applicable to the nodules in the Carstone,
which could be readily distinguished into indigenous and derived.

He thought it a matter for congratulation that they had had laid
before them another of the Author’s valuable contributions on this
interesting group of rocks, and trusted that Mr. Lamplugh would
eventually extend his observations to the South Coast.

Mr. H. B. Woopwarp remarked that, while in Dorset there was a
passage from Kimeridge Clay into Portland Beds, in Lincolnshire
the Spilsby Sandstone near Spilsby rested on Upper Kimeridge Clay
and north of Caistor it rested on Lower Kimeridge Clay, so that
there was a break between the nodule-bed and underlying clays.
He said that it should be borne in mind that a similar nodule-bed,
-also containing derived Portlandian fossils, occurred at the base of
ithe Woburn Sands at Brickhill, there resting on the Oxford Clay.

220 SPEETON SERIES IN YORKSHIRE AND LINCOLNSHIRE. [May 1896,.

Mr. R. 8. Herrizs congratulated Mr. Lamplugh on his paper
and said that from his knowledge of the Author’s excellent work at
Speeton he felt every confidence in the correctness of his inter-
pretation of the Lincolnshire sections. He was especially interested.
in that part of the paper which dealt with the boundary between
the Neocomian and Jurassic, as in this he saw the elements of a
reconciliation between the diverse views of Prof. Judd and the
Author. He wished to say how much assistance he had derived
from Prof. Judd’s paper while working on the Speeton section.

Mr. G. C. Crick desired to bear testimony to the value of the
paper. So far as the beds in question were concerned, he agreed
with the Author in using the belemnites to characterize the various:
zones. He mentioned that much of the confusion which had arisen
with respect to the determination of some ammonites, such as
Ammonites biplex, was due to the unsatisfactory conditions of the
types, some of these having been obtained from the Drift.

Mr. W. H. Huptzston also spoke.

The AvrHor was glad to learn that Prof. Judd was inclined
in the main to accept his results. As for the belemnites, their
peculiar value as zonal fossils in the area described was, not only
that they were abundant, but that owing to the intervention of the
southern forms of the jaculuwm-group between the lateralis- and the
brunsvicensis-groups of the northern eaplanatr, the boundaries were:
very definite and easy to trace. He was quite ready to grant to
~ Mr. Strahan and Mr. Woodward that an unconformity might exist at
the base of the Spilsby Sandstone, and even that true pebbles might
exist at this horizon, though he had himself failed to find any. His
contention was, however, that the phosphatized casts of fossils were
not derivative as had been supposed, but represented a fauna proper
to the horizon and to some extent distinct trom that of the overlying
portion of the Sandstone. The condition of the casts appeared to be
similar to that of the nodules dredged up by the Challenger ex-
pedition. He allowed that such nodules might form pebbles upon
the destruction of their original matrix, but held that this explana-
tion should be adopted only when the evidence was convincing, and
not in such cases as this, where (as he had tried to show) it was
insufficient. He thanked the Society for the kindly reception
accorded to his paper.

Vol. 52.] CRETACEOUS PODOPHTHALMATA. 221

9. On some PopoputHaLMatous Crustacea from the CRETACEOUS
“Formation of Vancouver and QurEN Cuartorre IsLanps.
By Henry Woopwarp, LL.D., F.R.S., F.G.S. (Read January

2nd, 1896.)

Some time since I received from my friend Mr. J. F. Whiteaves,
F.G.S., Palezontologist to the Geological Survey of Canada, several
interesting crustaceans from the Cretaceous coal-bearing formation
of Vancouver and Queen Charlotte Islands, and, as they offer a close
affinity with forms from our own Gault and Greensand, they are
deserving of special notice.

The existence of Cretaceous strata in Canada has long been
known, and the coal-fields of Nanaimo and Comox on Vancouver
Island have been correlated with this formation as well as those
of Queen Charlotte Island and Alberta, eastward of the Rocky
Mountains.

Mr. F. B. Meek in 1857 gave a description of new organic
remains from the Cretaceous of Vancouver Island, including Bacu-
lites ovatus ? Say ; Ammonites (Scaphites) ramosus, A. Newberryanus,
Dentalium nanaimoensis, Thracia(?) occidentalis, Thr.(?) subtrun-
cata, Trigonia Evansana, Pholadomya subelongata, Ph. (Goniomya)
borealis, Cardium scitulum, Arca vancouverensis, A. (Cucullea) equi-
lateralis, and Nucula Traskana. Dr. B. F.Shumard in 1858 added
Inoceramus vancouverensis, Pinna calamitoides, and Pyrula glabra
to the Nanaimo fauna.

In Prof. H. Y. Hind’s ‘ Report on the Assiniboine and Sas-
katchewan Expedition’ (1859) further lists of fossils are given, 13
in number, all referred to Cretaceous forms, namely :—

Anomia Flemingii. Leda Hindi, Meek.
Inoceramus canadensis, Avellana concinna, H. & M.
Avicula lingueformis, HK. & 8. Ammonites placenta, Dekay.

nebrascana, E. & 8. Scaphites nodosus, Owen, var.
Leda Evansi, Hall & Meek. Conradi, Morton.

Rostellaria americana, KE. & 8. Nautilus Dekayi, Morton.
Natica obliquata, Hall & Meek.

In 1861 Dr. (now Sir) James Hector instituted a comparison
between the strata east of the Rocky Mountains with those of
Vancouver Island (Capt. Palliser’s Exploring Expedition, 1857-60).!
The list of Cretaceous fossils contributed by Mr. Etheridge from.
east of the Rocky Mountains comprised :—

Ostrea anomieformis. Astarte terana, Conrad.
lugubris, Conrad. Cardium multistriatum, Shumard.
cortex, Conrad. Cytherea texana, Conrad.
vellicata, Conrad. Pholadomya occidentalis, Morton.
* Inoceramus Crippsiit, Roemer & C. Baculites compressus, Say.

Leda Hindi, Meek.

* Inoceramus Crippsii (Roemer) and Baculites compressus (Say) are stated to-
be common to the Cretaceous rocks of the plains and of Vancouver Island ;
while of the whole 18 species no less than 13 are identified with Texan or
Mexican species.

? Quart. Journ. Geol. Soc. vol. xvii. (1861) pp. 388-445.

222 DR. H. WOODWARD ON CRETACEOUS PopoPpHTHALMATA [May 1896,

Those from Nanaimo, Comox, or Valdez Inlet are :—

Inoceramus texanus, Conrad. Inoceramus mytiloides, Conrad.
nebrascensis, Owen. Trigonia Emory, Conrad.

_— undulatoplicatus, Roemer. Cytherea leonensis, Conrad. :

confertim annulatus, Roemer. Ammonites geniculatus, Conra J

In 1861 Mr. Meck (Proc. Acad. Nat. Sci. Philad. vol. xiii. p. 314)
added to the list of Cretaceous fossils from Wancouver Dosina
tenuis, from Nanaimo ; Inoceramus subundatus, Baculites occidentalis,
Ammonites vancouverensis, and Nautilus Campbell, from Comox 5
Ammonites compleaus, var. suciensis, from Comox and the Sucia
Islands ; and Baculttes inornatus, from the Sucia Islands. ;

In 1864 Mr. W. Gabb, in vol. i. of the ‘ Paleontology of Cali-
fornia, described and figured two new species of fossil shells,
namely :—Hamites vancowverensis and Pecten Traskw from Nanaimo.

For an admirable summary of our knowledge of ‘the Cretaceous
System of Canada,’ see the Presidential Address to the Royal Society
of Canada by J. F. Whiteaves, Section iv., May 23rd, 1893, pp. 3-
19 (Trans. Roy. Soc. Canada). i

I find that it is impossible here to give a full list of all the fossils
obtained from these beds, and-I have omitted the fossils of the
upper series of deposits entirely, as also the plant-remains.

Besides the mollusca, a decapod crustacean (named but not
described as Hoploparia or Podocrastes? dulmenensis) has been
recorded from the Niobrara-Benton group of Manitoba—a long-
tailed decapod (Palcastacus) from the Pierre Fox Hills or Montana
formation, and a beetle, Hylobites cretaceus, Scudder, from the Pierre
Shales, Millwood, Manitoba.

The species of crustacea now to be noticed comprise:— =

1. Several examples of a small macrurous decapod belonging to
the genus Callianassa, met with very frequently in the Faxoe Beds,
the Maestricht Chalk, the Greensand of Colin Glen, Belfast ;* and
also from lower beds (C. isochela),? Kimeridge Clay of the Sub-
wealden boring; and from higher and later ones, namely, Callia-
nassa Bate?,? Upper Marine Series, Hempstead, Isle of Wight.

This is a small burrowing crustacean, and is found living at the
present day; usually only the chele are obtained in dredging,
owing to the animal lying in its burrow, and the hands alone pro-
truding from the aperture. :

The body- (thoracio-abdominal) segments are nearly soft, owing
to the animal’s constant habit of lying concealed, only the hands
haying a hardened calcareous covering.

1 Callianassa neocomiensis, H. Woodw. Brit. Assoc. Rep. (Norwich) 1868,
pif, pl. 1. fie. 5, gh

2 C. isochela, H. Woodw. Quart. Journ. Geol. Soc. vol. xxxii. (1876) p. 47,
spl. xxxii, figs. 1, 2. g

3 C. Batei, H. Woodw. Brit. Assoc. Rep. (Norwich) 1868, p. 74, pl. ii. fig. 4.

Vol. 52.] FROM BRITISH COLUMBIA. 223

I. MACRURA.

Tribe THALASSINIDBEA,

Family Callianasside.
Genus Catxianassa, Leach, 1814.

1. Callianassa Whateavesii, sp. nov. (Figs. 1 & 2.)

General integument of body extremely thin, or semimembranous,
except the first pair of feet, which are protected by a hard covering.
Anterior feet (chelipeds) very unequal; length of larger limb
39 millim.; breadth 9 millim.; the dactylus is straight, and is
9 millim. long, but the fixed thumb of the propodos is rudimentary
and stout, being only half as long as the movable finger. Length
of smaller hand about 20 millim. Surface of hands faintly wrinkled.

There are indications of the
segments of the abdomen and Fig. 1.
of the thin integument with
which they were covered, also
of the small thoracic legs, but
they are too much broken up
for detailed description.

In this species from Van-
couver Island the fixed thumb
of the propodos is shorter than
in any of the species hitherto
recorded, and the movable
finger (dactylus) is straighter.

The species is smaller
than that from the Chalk of
Dulmen, Westphalia, or from
Maestricht, or Belfast. I
have designated it Callianassa
Whateavesi, in honour of my
friend Mr. J. F. Whiteaves,
who has done so much for the
elucidation of the Cretaceous
formation in Canada.

Original specimens preserved in concretionary nodules of Cre-
taceous age from Comox River, Vancouver Island. Collected by
Dr. C. F. Newcombe (1892), Museum of the Geological Survey of
Canada, Ottawa.

A nodule from Vancouyer Island, in the Geological Society’s
Museum, contains the remains of the large hands of Callianassa

Whateavesii. A second Nodule from the same collection contains the
carapace of Plagrolophus yancouverensis.

224 DR. H. WOODWARD ON CRETACEOUS POPOPHTHALMATA [ May 1896,

II. BRACHYURA—ANOMALA.
Family Homolide.

Genus Homo toprsis, Bell.

Carapace longer than broad, quadrilateral; regions of carapace
very distinct; branchial region large, triangular; orbits close
together, frontal region rather produced ; front subrotund.

2. Homolopsis Richardsoni, sp. nov. (Fig. 3.)

This interesting little crab was obtained by Mr. James Richardson
in 1872 from Skidegate Inlet, west of Alliford Bay, Queen Charlotte
Island, and is preserved in a hard black limestone-nodule containing
plant-remains. Portions of the limbs still remain in their normal
position, showing that it was entire when originally buried in the
matrix.

Length of carapace 20 millim., greatest breadth 17 millim. ;
breadth of posterior border 14 millim.; breadth across hepatic
region 14 millim.

The carapace is broadly quadrilateral, but pointed in front; the
branchial regions extend to fully one half the length of the
carapace; they are roughly
triangular in shape, and :
nearly meet on the middle | Fig. 3.
line behind the cardiac re-
gion; cardiac region small,
shield-shaped, but elevated ;
metagastric region marked
by two small prominences ;
hepatic regions prominent.
Two very distinct and almost
parallel furrows, the bran-
chial furrow and cervical
or hepatic furrow, diverge
from the sides oft he cardiac
and wmetagastric regions
obliquely forward towards the lateral margins of the carapace. Two
deep submedian furrows mark the frontal portion of the cephalo-
thorax, reaching to the rostrum, where they converge on the central
line. Two small spines (or other appendages) project (as in the
genus Latreillia) from the rostrum on either side.

The hinder border is extremely wide and straight, and suggests
the broad margin for the attachment of the tail as in the females of
all the Anomala, in which section the abdomen is only partially
concealed beneath the cephalothorax.

The surface of the carapace, which is tumid, is coarsely and
irregularly covered with small rounded tubercles, which are larger
on the gastric and hepatic regions. |

The walking-legs were evidently long and fairly large, and the
chelipeds curved and tuberculated as in Homola. ~

“Vol. Be: FROM BRITISH COLUMBIA. 995

This species has many points of resemblance to Reuss’s Prosopon
werrucosum, from which, however, it differs in the greater anterior
breadth of Reuss’s specimen, and in the form of the rostrum and
arrangement of the furrows upon the gastric and cardiac regions.
Reuss’s P. verrucosum should probably be placed in Bell’s genus
Homolopsis.

In Homolopsis Edwardsii, Bell, from the Gault of Folkestone, the
frontal border is broader and the carapace more quadrate than in
the North American form, which is pointed in front; the anterior
half of the carapace in H. Hdwardsw is more coarsely ornamented
with fewer and larger tubercles, and the arrangement of the lobes
differs considerably from that in H. Richardson.

I would refer this specimen to Homolopsis, and dedicate the
species to the discoverer, Mr. James Richardson.

The specimen is from the Museum of the Geological Survey of
Canada, Ottawa.

Legion OxYsToMATA.
Family Corystide.

Genus Patzocorystss, Bell.

In this genus the carapace is longer than broad, flattish, becoming
narrower gradually towards the posterior border, rostrum short,
latero-anterior border dentated. Orbits moderately broad, with
two fissures.

The carapace in all the species of this genus at present known is
‘similar to that of the masked crab, Corystes, now living on ovr
‘English coasts.

3. Paleocorystes Harveyi, sp. nov. (Fig. 4, p. 226.)

The genus Palcocorystes, to which I have referred two of the
specimens sent to me by Mr. Whiteaves, is well represented in the
Gault, Greensand, Chalk, and Eocene.

Thus we have :—

Paleocorystes Broderipti, Mantell, sp. ; Gault, Folkestone.

Stokesti, Mantell, sp.; Gault and Greensand, Cambridge and
Folkestone.

Normanni, Bell; Chalk Marl, Isle of Wight.

— Miilleri, Bink; Upper Chalk, Maestricht.

— Callianassarum, Fritsch ; Chalk, Bohemia.

-—— isericus, Fritsch ; Chalk, Bohemia,

glabra, H. W.; Lower Eocene, Portsmouth.

Eucorystes Carteri, M‘Coy ; Greensand, Cambridge.

Both the specimens from Canada are imperfect. One of them
(No. 2) shows the anterior upper surface of the carapace, the other
(No. 3) the posterior upper surface. From these we are able to
make the following diagnosis :—

Specific characters. Length of carapace 35 millim., from the
rostrum to the broken posterior border (to this we must probably

226 DR. H. WOODWARD ON CRETACEOUS PODOPHTHALMATA [May 18096,.

add 15 millim. more, making the total length from the rostrum
to the posterior border of the cara-

pace 50 millim.); greatest breadth Fig. 4.
across the hepatic region 37 millim. a

(No. 2 was collected by Mr. W. 0:
Harvey, Comox River, Vancouver
Island, 1892; No. 3 by Dr. C. F.
Newcombe.)

Carapace smooth and gently convex
in front, and very finely and minutely
granulated. Latero-anterior border
armed with four serrations on each
side, frontal border marked by one
prominent and one smaller tooth on
either side of the small bifid rostrum,
while two fissures mark the margin
of each orbit. Under surface of .
carapace not exposed.

The regions of the carapace are
very indistinct; two slightly divergent raised lines about 5 millim.
in length mark the frontal region just behind the rostrum, and
there is a faint ridge down the centre of the carapace. <A small
tubercle on. either side, behind the frontal region, marks the
epigastric lobe. A faint curved and bifurcating line separates the:
gastric from the cardiac regions, while two slightly rugose and
incised lines curve outward and forward from the central cardiac
region, marking the limits of the branchial region on either side.

Of the several species of Palwocorystes known, the present form,
which I have ventured to call P. Harveyi after its discoverer,
approaches most nearly to P. Broderipu from the Gault of Folke-
stone, but is probably one-third larger. The latero-anterior border
of the former (P. Harvey) has four spines on each side, whilst
P. Broderipw has only two. The orbital regions differ in form, as
well as the markings on the regions of the carapace.

We must await more complete materials before attempting a
fuller and more careful description; meantime it is interesting to
meet with a species from so distant a locality which apppoaches so
nearly to our own Gault species P. Broderipi.

Formation.—Cretaceous. Localities—Hornby Island (No. 2);
and Comox River, Vancouver Island (No. 3).

No. 2 belongs to the Provincial Museum, Victoria, Vancouver
Island; No. 3 belongs to the Geological Survey of Canada.

Legion CycLoMETOPA.
Family Cancride.
Genus Piagiotoputs, Bell.

In this genus the carapace is transversely ovate, the regions of
the cephalothorax are distinctly marked, front somewhat prominent, ~

Vol. 52.] _ FROM BRITISH COLUMBIA. 227

the eyes subdistant, superior border of the orbits with two fis-
sures, etc.

4. Plagiolophus vancouverensis, sp. nov. (Figs. 5 & 6.)

This crab is represented by four specimens, three of which I
received from Mr. Whiteaves, and the remaining one is preserved in
the Museum of the Geological Society.

The carapaces vary in size from :—

Millimetres
OO
long. broad.
1. Geological Society’s specimen ...... 22 28
2. From Comox River, Vancouver Island
“Nc Std 4p uta ace lade tee orphan RRR 41 25
Been. WW. side, Hornby Usland: 2... 5 16 20
4. N.W. side, Hornby Island (fig. 6) .. 10 13

No. 1 and No. 2 are 7 broader than long, No. 3 is +, and No. 4
is i broader than long.

The frontal border is straight; the rostrum is bifid, with two
small rounded elevations divided by a groove ; the orbital region is
smooth and but little indented; the lateral borders are very gently
rounded, the posterior border is nearly straight. The cardiac and
metabranchial lobes, the metagastric and epibranchial lobes, and
the two mesogastric lobes form three almost parallel lines across the
carapace, giving lt a very unique linear arrangement; there are
also two much smaller lobes, one behind each of the orbits, flanked
laterally by a small tubercle, and a small rounded tubercle on each
epibranchial lobe ; the lateral border was bluntly dentated.

Fig. 5.
Fig. 6.

When not waterworn (as in specimen No. 4), the surface of the
carapace is in parts very finely granulated.

‘These specimens are very distinct, but without more materials [
should not feel justified in separating them generically. I prefer
rather to place them in Bell’s genus Playiolophus, which was
proposed to receive P. Wetherelli, from the London Clay of Sheppey.

Q.J.G.58. No. 206. R

228 CRETACEOUS PODOPHTHALMATA, [May 1896,

- The’ same species—described under the name of Glyphithyreus
affinis (Reuss)—was figured and described by Reuss nearly at the
same date. Reuss also adds another species, Glyphithyreus for-
mosus, Reuss, from the Upper Cretaceous of Mecklenburg.

I feél satisfied to leave these Vancouver Island crabs in this
-genus, and to designate them by the trivial name of vancouverensis.

Two specimens were collected on the north-western side of
Hornby Island, and one on Comox River, Vancouver Island, British
Columbia. ‘The locality of the Geological Society’s specimen is not
marked, but it is from Vancouver Island.

Nos. 8 and 4, from Hornby Island, belong to the Provincial
Museum of Victoria, Vancouver Island.

No. 2 specimen shows traces of limbs, and the flattened propodos
of a chelate fore-arm 13 millim. long x 8 millim. broad,

Kok, s2e.p)’ CALAIS NEWBOLDI FROM THE LEBANON, 229

10. Ona Fossiz Octopus (Catars Newnoxpr, J. De C. Sby. MS.)
from the Creraczous of the Lesanon. By Henry Woopwaxp,
LL.D., F.R.S., F.G.S. (Read January 22nd, 1896.)

[Puate VI.]

I am indebted to Mr. C. Davies Sherborn, F.G.S., for drawing my
attention to a very remarkable and beautiful fossil from the
Cretaceous formation of the Lebanon, Syria, obtained about 1846
by Lieut. T. J. Newbold, and preseuted by him to the Museum
of the Geological Society, where it has since remained. In 1846 it
attracted the attention of Mr. J. De Carle Sowerby, who evidently
intended to describe it, ‘at a more convenient season,’ which never
arrived ; for he wrote upon it :—

‘ Calais Newbouldii’ (read Newbold). ‘CrrH. Ocropopa. Genus
aneditum. Abdomen alis triangularibus instructum,

‘ £ strato calcareo tertiario Montis Liban a D, (T. J.) Newbo(uyld
effossum 1846. J. De C. Sowzrsy.’

The only criticisms that I would venture to make upon this label
are (1) that the stratum of limestone from the Lebanon, whence the
fossil was derived, is not of ‘ Tertiary’ but Cretaceous age ; (2) that
the specimen is marked in pencil on the back ‘ Major Newbold,
Mt. Lebanon’ (whose initials were ‘T. J”=‘Thomas John’)
not D., and there should be no w in Newbold. He is spoken of
in 1842 as ‘ Lieut. Newbold’ (Proc. Geol. Soc. 1842, pp. 782-792),
and by Murchison in his Presidential Address, Feb. 17th, 1843,
as ‘ Lieut. Newbold, of the East India Company’s service’ (Proc.
Geol. Soc. vol. iv. 1846, p. 137).

[In the ‘ National Biography,’ 1894, pp. 314-315, Newbold is spoken of as
one of the most accomplished officers in the East India Companys service. He
was made a Lieutenant in 1834; and, while serving in Malacca, was Aide-de-
camp to Brigadier-General E. W. Wilson, C.B. In 1840 he obtained leave
and visited Egypt, Sinai, and Palestine, when he no doubt secured the fossil
now under consideration. He was made a Captain, April 12th, 1842; but his
later rank of Major is not mentioned by hie biographer. He died at
Mahabuleshwar on May 29th, 1850, at the age of 43 years. He wrote several
important works on Indian Geology, on Egypt, the Sinaitic Peninsula, and
Palestine, and he contributed 46 papers to various learned Societies. ]

Prof. Lewis says, ‘There are two principal localities for Cre-
taceous fossils known and recorded in the Lebanon, namely, Hakel
and Sahel-el-Alma, and a third of minor importance, called
Hazhila (Djoula on the French military chart), about 2 hours and
a halt south of Hakel.

‘Hakel is the oldest known locality, though it has been but
rarely visited. It is a long day’s journey from Beirait, and is
situated at about 800 to 1000 feet of elevation above the sea, and
distant from the sea in a straight line about 6 miles.

‘Sahel-el-Alma is nearer to Beirtit, and may be visited from the

R2

230 DR. H. WOODWARD ON A FossIL octopus [May 1896,

latter place in one day, with an allowance of two or three hours at
the locality.

‘The rock at Hakel is somewhat harder than from Sahel-el-Alma,
very fissile, and can be readily trimmed with the hammer.

‘The section at Sahel-el-Alma is under the very walls of the old
Convent, which gives its name to the spot; here, in a fig-orchard,
outcrops the stratum of white chalky limestone where so many
beautiful fossils have been obtained, and whence comes also the
Calais Newboldii.’

The following is a brief summary of the bibliography of this
classical locality :—

The existence of fossil fishes in the Lebanon is referred to in
Joinville’s ‘ Histoire de St. Louis ’—edited by M. Natalis de Wailly.
During the sojourn of the king at Sidon in 1253, just before his
return home from the Crusades, a stone was brought him, says
Joinville, ‘ which was the most marvellous in the world, for when
a layer of it was lifted, there was found between the two pieces the
form of a fish. The fish was of stone, but lacked nothing in form,
eyes, bones, colour, or anything necessary to a living fish. The
king demanded a stone and found a tench within.’

M. de Blainville described Clupea brevissima and Clupea Beaurard,,
from Hakel, in the Lebanon, in 1818.

Nir: Chas. Koenig, 1820, in his ‘ Icones Fossilium sectiles,’ figured
Ophiura libanotica and Euryale Bayert, pl. ii. figs. 26 and 27, from
the Cretaceous of the Lebanon.

Prof. L. Agassiz, in 1833-43 (‘ Poissons fossiles’), described two
species of Clupea from Hakel, and a Sphyrena and Rhinellus from
Sahel-el-Alma.

Sir Philip Egerton added an account of Cyclobatis from Hakel
(Quart. Journ, Geol. Soc. vol. 1. p. 225) in 1845. |

Prof. Haeckel described two species of Pycnosterinx from Sahel-
el-Alma, and a new species of Clupea from Hakel, in 1849.

Mr. O. G. Costa described Imogaster, Omosoma, and Beryx in 1855.

In 1866 MM. Pictet and Humbert (‘ Nouvelles Recherches sur les
Poissons fossiles du Mont Liban ’) described 26 species of fishes from
Sahel-el-Alma and 21 from Hakel.

(Leptosomus macrurus, described by Pictet and Humbert, Upper
Cretaceous, Sahel-el-Alma, Mount Lebanon, is one of the fishes asso-
ciated on the same slab with Calais Newboldi, the subject. of this

aper.)
z Dr. Louis Lartet, in his fine memoir, ‘ Exploration géologique de
la Mer Morte, de la Palestine et de ’Idumée’ (1877), recorded, at
p. 112, Crass CepHatopopa. 1. Ocropopa, ‘ Caluis Newboldri,'
Sow. Empreinte de Céphalopode dans les Calcaires 4 Poissons du
Liban (Collection de la Société géologique de Londres),’

Lartet also mentions the remains of cephalopods of the Fly
Sepiade from the same Cretaceous Limestone of the Lebanon (pre-
served in the Paris Museum).

1 (The ¢ in the specific name should be omitted.) ‘ Cette empreinte curieuse,
trés-bien conseryvée, a été recueillie par M. Newboldz,’

Vol. 52.] | FROM THE CRETACEOUS OF THE LEBANON. 231

Prof. Dr. Oscar Fraas, in his work, ‘Aus dem Orient,’ 1878,
pt. ii. (Stuttgart), figures and describes 28 species of invertebrata,
echinodermata, mollusca, crustacea, etc., and 1 fish (Gyrodus) from
the Cretaceous of Syria. He figures one dibranchiate cephalopod
(Geoteuthis libanoticus) and 1 ammonite.

Dr. Fraas mentions that he saw in the collection of the Rev.
Prof. E. R. Lewis, at the Syrian Protestant College, Beirit, a
specimen of WSepialites with eight arms, of which he secured
a photograph; and that Sowerby had long ago obtained from
the Lebanon an Octopus collected by Mr. Newbold, to which he
had given the name of Calais Newbold: (‘ Aus dem Orient,’ ii.

. 90).
4 In the same year (1878) the Rev. Prof. Lewis, F.G.S., gave an
interesting description of the Fossil Fish Localities of the Lebanon
in the Geological Magazine (pp. 214-220).

In 1879 I described before this Society Squilla Lewis and
Limulus syriacus from the Lebanon Cretaceous (see Quart. Journ.
Geol. Soc. vol. xxxv. pp. 552-556, pl. xxvi.).

In 1883 I described a new genus of fossil ‘ Calamary,’ Dora-
teuthis syriacus, from the Cretaceous of Sahel-el-Alma (see Geol.
Mag. 1883, pp. 1-5, pl. i.).

In 1882 Mr. W. H. Hudleston, F.R.S., gave in his Presidential
Address to the Geologists’ Association an admirable account of the
‘(zeology of Palestine,’ in which the geological horizon of the Hakel
and Sahel-el-Alma deposits is discussed, with a coloured map and a
plate (Proc. Geologists’ Association, vol. viii. 1883-84, pp. 1-53)
(see also ‘ Further Notes, Proc. Geol. Assoc, vol. ix. 1885,
pp. 77-104).

In 1886 Prof. Dr. W. Dames published an account of ten genera
and twelve species of crustacea trom the Cretaceous of the Lebanon.
Among them is one figured and described as Protozoéa Hulgendorft,
Dames, which is represented by three specimens on the slab which
contains Calais Newbold: (Zeitschr. d. deutsch. geol. Gesellsch.
vol, xxxvill. 1886, p. 577, pl. xv. figs. 5-7),

The fossil remains of Calais Newboldi are preserved as a delicate
ferruginous impression upon the biscuit-coloured surface of one of
the fissile slabs of Cretaceous Limestone from Sahel-el-Alma,
Mount Lebanon.

The slab is 93 inches long by 8 in breadth and 1 in thickness,
displaying remaius of fossil organisms upon both its surfaces.

These consist of several small well-preserved fishes, Leptosomus
macrurus, Pictet & Humbert, and a small crustacean carapace
(believed to be a zoea-furm) and named Protozoéa Hilgendorfi by
Dames.

The Octopus, which occupies the centre of the slab, exhibits its
eight arms (or more properly feet or ‘ podites’), each furnished
with a row of suckers, which diminish in size gradually from their
base to the very slender extremities of the podites. Near the
union of the podites with the head, there is a faint trace of what

232 DR. H. WOODWARD ON A FossIL octopus’ [May 1896,

may have represented the umbrella, or ‘ web,’ which age ne
the arms or podites together.

In the centre of the head (between the bases of the arms or
podites) is.a darker and denser spot of brown showing evidence of
the beaks,—marking the position of the mouth; below this again
is a small slightly-raised orifice, which probably marks the opening
of the funnel. Two remains of fishes lie across the neck ana
separate the head and arms above from the round wrinkled body
beneath, with its triangular fins, a feature which at once peice?
characterizes this genus.

An injudicious attempt to develop the two mutilated fishes, lying
across the Octopod, has resulted in the unfortunate removal of a
part of the thin and delicate layer on which the Nature-painting of
Calais was preserved. In the centre of the body is an oval
depression or cavity 8 mm. long and 4 mm. broad, once occupied by
the ink-bag. The breadth of the body is 40 mm., and to the
extremity of the lateral fins 64 mm.; height of fin 14mm. Length
of arms rather over 100 mm. Breadth of arm near the head about
5 mm., but diminishing rapidly to 4 and 3 mm., and terminating in

a slender whip-like extremity.

There appears to be only a shee. row of suckers upon each arm,
as in the genus Eledone, and about 30 suckers in each row. The
suckers vary 1n size from 2 mm. in diameter to less than 1 mm.
Some of the suckers seen in profile stand up as much as 2 mm. from
the surface of the arm.

There is a faint trace of the presence of an umbrella, or web,
uniting-the bases.of the arms around the mouth to a distance of
about 15 mm. The arms were evidently very flexible, judging
by the graceful curves which they have assumed even in death.
They are also seen to be of nearly equal size and length, so far as
can be ascertained.

As I have already stated, the triangular ‘ale,’ or more properly
‘ fins,’ are characteristic of Calais. 8. P. Woodward (‘ Manual of
the Mollusca,’ p. 64) says of the Octopods, ‘ their bodies are round,
and they seldom have fins.’

In Pinnoctopus the body has lateral fins united behind (ex. 2,
cordiformis). In Cirroteuthis the body has two transverse fins. In
Calais, as we have seen, the body is round, but it is provided with
triangular lateral fins (not united behind).

In the decapoda—cephalopods with eight arms and two tentacles,
or, as they are often called, ‘ tentacular arms ’—the body is oblong or
elongated, and is always provided vis a pair of lateral or nearly
terminal fins.

Seprola has rounded dorsal fins, but in very many echeny the he
are terminal and often rhombic or angular.

The question of the position of the arms, whether uniform in size
and freely-moving, or differing in size and position in relation to the
dorsal and ventral aspect of the body, is of some aie even in
studying these fossil remains.

Thus, for example, in his work, las asia Orient,’ vol. ii. p. 90,

Vol. 52.]:*° FROM THE CRETACEOUS OF THE LEBANON. , 233°

Dr. Fraas refers to a specimen which he had seen at Beiriit in the

collection of the Rev. Prof. Lewis; this showed. the head | of.
a sepialite with its eight arms close together, and, as he says,

reminded him of the fossilforms from the Lias, figured and described.
by Quenstedt.

- Dr. Fraas obtained a photograph of this ‘sepialite’ from Prof.

Lewis, which was afterwards lent to Mr. G. C. Crick, F.G.S., who-
compared it with specimens obtained by the British Museum from

the late Prof. Lewis, and was happily able to identify by its aid the:
original of Dr. Fraas’s remarks.* Z
_ The specimen proves to be the head and arms of a decapod

cephalopod allied probably to Onychoteuthis, showing the eight.
ordinary arms, but with only a faint trace preserved. of one of the:
long tentacular arms.

The arms are close together and nearly straight, and are arranged
in pairs. First there.is a pair of slender and short dorsal arms, then
two pairs of | :
verystoutand Plesioteuthis Fraasii, sp. nov., from the Cretaceous —
longer lateral of the Lebanon. |
arms, and,
lastly, another :
pair of some- &
what shorter ae
and more
slender ven-
tral arms.

No suckers
are visible on
the arms,. but
there are
traces of what
appear to be
hooklets and
serrations in
two or three
places, sothat,
taken in con-
nexion with
the more rigid
carriage of
the arms and
their arrange-
ment in pairs,
we may feel
assured that * a ae
this is not an octopod, like Calais, but a true Teuthid? and
probably related to Dorateuthis (see Geol. Mag. 1883, pl. i. p. 1).

1 The photograph was marked in pencil Calais Newboldi.
? If a name be desired, I would suggest for this sepialite the name of
Plesioteuthis Fraasii, after the author of ‘ Aus dem Orient,’

234 CALAIS NEWBOLDI FROM THE LEBANON. [May 1806,

Length of the largest arms 7 inches, of the shortest pair of dorsal
arms 4 inches ; the second or ventral pair of slender arms are 5 inches
long. The head with the arms is nearly 10 inches in length. The
beak is ? inch in length and ;4 inch broad at its base.

At present, so far as my information serves, Calais Newboldi
remains the oldest and only known fossil octopod.

I have retained Mr. J. de Carle Sowerby’s original name, it having
been already recorded in print by Dr. Oscar Fraas and by Dr. Louis
Lartet in their respective works already referred to.

The genus Calais is derived from Calais, the brother of Zetes (sons of Boreas

and Orithyia), frequently called the Boréadz (mentioned among the Argonauts),
and described as winged beings. [Smith’s Classical Dictionary, 1883.]

Postscript.

The genus Dorateuthis, proposed by myself in 1883, is by Zittel
included in the genus Plesioteuthis of A. Wagner (1860), which has
also a tricarinate internal pen with a spatulate distal expansion.

There are now in the British Museum (Natural History) as many
as ten Teuthide,' the largest of which is 20 inches in length, and
exhibits the body, head, and arms in union. The smallest is not so
large as D. syriacus, H. W. (1883). They all possess tricarinate
shells.

I hope to offer some further notes upon these very well-preserved.
decapod cephalopoda from the Lebanon later on, with the promised
kind co-operation of Mr. G. C. Crick, F.G.S., who has devoted so
much attention to the cephalopoda generally, and to whom I am
indebted for information and assistance in preparing this paper.

PLATE VI,
Calais Newboldi from the Cretaceous of the Lebanon.

DiscussIon,

Mr. Crick stated that, as the occurrence of this fossil had been
already at least twice recorded, and as neither a description nor a
figure had been given hitherto, it was most important that the
specimen should be described and figured, and it was very fortunate
that the fossil had come into the hands of the President for de-
scription. He believed the specimen to be a true octopod ; it was
therefore the oldest known representative of this division of the
cephalopoda,

1 All from Prof, Lewis’s collection of Lebanon Cretaceous fossils,

Quart. Journ. Geol. Soc Vol L]] PE Wie

th.

M.Woodward del. et li

G

CALAIS NEWBOLDI.

Vol. 52,] | THE BRITISH SILURIAN SPECIES OF ACIDASPIS, 235

11. The British Sirvrian Specizs of Acrpasris. By Purrip Lake,
Esq., M.A., F.G.S. (Read December 18th, 1895.)

[Puates VII. & VIII.}
ConTENTS. Page
RIE SAEED Wie gio ce ae pte tno gia aries isha ve salnnng asc ssvspatesseggsaus sncns 235
Re ERPEN NIGH OL SS PCEIOS aos. cote ness tnanaana sumac cn teas ¢e¥navecceacsenennenacen 236
III. Comparison with the Swedish and Bohemian Faunas..................++ 244

I. Intropvuction,

Tue genus Acidaspis has been a peculiarly unfortunate one in
Britain. Several of the specific names which are in common use
are manuscript terms, or but little better; and the species to which
they are applied have never been described. It is impossible, there-
fore, without access to standard collections, to determine to what
forms the names refer. Even the species which have been described
have in many cases been imperfectly figured, and the result is
endless confusion. The common English trilobite, A. coronata, has
received abroad no less than three names, all of them different from
ours; while in England, on the other hand, the foreign name A.
crenata is often applied to a species which is quite distinct from
the original A. crenata, and which in fact has never yet been found
out of Britain.

_ The disorder is worst among the Silurian forms, although these
are much the most perfect. The Ordovician species are usually
fragmentary, hut the fragments have been fully described.

It is the object of the present paper to attempt to reduce the
specific terminology to some sort of order, and to rescue the common
manuscript names from the obscurity in which such terms tend to
become involved after a lapse of time. Only the Silurian forms are
here described ; the Ordovician species have been left in the hope
that better material may be forthcoming in the future.

Even the name of the genus itself is matter of controversy.
Murchison * employed the term Acidaspis in 1839, and in the same
year Emmrich ” proposed the name Odontopleura. The latter is often
used in Germany, but the former is the more widely spread. There
is, however, an earlier name still, the use of which has been advocated
by Vogdes® and J. M. Clarke,* though Vogdes, in his bibliography,’
does not adopt his own suggestion. This name is Ceratocephala,
and was applied by Warder® in 1838 to a species which he called

? ‘Silurian System,’ p. 658.

2 ‘De Tril. Diss. inaug.’ 1839, Berlin,

* Proc. Acad. Nat. Sci. Philadelphia, 1877, p. 138.

4 44th Ann. Rep. New York State Museum (18Y1), p. 91.
5 Bibl. Pal. Crust. 1893, San Francisco.

§ Amer, Journ. Sci, & Art, vol. xxxiv, no. 2 (1838), p. 377.

236° .. MR. P. LAKE ON THE BRITISH | _ [May 1896;

Ceratocephala goniata, and which belongs to the same group as
A. vesiculosa etc. Warder’s name was rejected by Corda on the
ground that it had already been employed, in the form Cerato-
cephalus, for a genus of plants ; but even if it be eligible, its rival,
Acidaspis, has been so widely used for so long a time that, here at
least, I do not propose to adopt any. other.

II. Descriprion oF SPECIES.

AcrpasPis Brieut1, Murch. (Pl. VII. fig. 5.) —

1839. Acidaspis Brightii, Murch. ‘ Sil. Sy st.’ p. 658, pl. xiv. fig. 15; 1848. Salter,
Mem. Geol. Surv. vol. 11. pt. 1. p. 348, pl. 1X. figs. 6(?), 7 (not figs. 8, 9).
(Not Odontopleura Brightii, Beyrich, ‘Unters. tiber Tril.’ p. 20, ‘pl. ii. fig. 6.)

Head transverse, crescentic, with one occipital and two genal
prolongations or arms; tuberculate. Glabella prominent; central:
portion nearly uniform i in width throughout, but slightly contracted
between the second pair of lateral lobes; lateral lobes two on each
side, almost completely separated from the central portion; the
basal lobe much the larger of the two. Occipital ring very indi-
stinctly separated from the glabella, produced backward into a single,
strong, straight median spine. Eyes placed far back, and very
near to the basal lobe of the glabella; connected with the front
end of the glabella by a nearly straight ocular ridge. Free cheeks
small, with a raised margin, which bears a number of spines directed
downward; genal angles produced into long and strong spines,
which form a continuous curve with the posterior margin of the
head, but make a distinct angle with the external margin.

Horizons and Localities —Wenlock Limestone: Dudley. Lower
Ludlow: near the Wych, Malvern. It has been recorded from the
Bala beds, but this is probably due to mistaken identification.

_ Affinities—Only the head is known with certainty. It closely
resembles A. Gray, Barr., but is distinguished, as Barrande has
pointed out, by the following characters :—(1) the genal spines in
A. Brighti are inclined to the axis at an angle of about 45°, while
in A. Grayi they are nearly at right angles to it; (2) the occipital
spine in A. Brighti is usually somewhat smaller than in A. Grayi,
and does not bear the prominent tubercle characteristic of the latter ;
(3) the ocular ridge in A. Brighti is nearly straight, in A. Grayt
strongly arched ; (4) the granulation in A. Bright is much coarser
and stronger than i in A. Grayi.

It is easily distinguished from all other British species by the
single strong occipital spine.

_ Remarks on the Synonymy.—The species was originally described
and figured by Murchison, and formed the type of his. genus
i. In 1848 Salter gave a fuller account of the form; but
unfortunately he confounded two species under the same name, and
figured two distinct heads and two distinct tails. One of the species
is identical,with Paradoaides quadrimucronatus, Murch., and hence
this name is usually quoted as a synonym of 4A. Brighii. Sub-
sequently Salter recognized his error, and,in 1857 he described the

Vol. 52.]°" SILURIAN SPECIES OF ACIDASPIS. 237

second species under the name of A: coronata. This, and not
A. Brighti, is the Paradoxides quadrimucronatus of Murchison.

Beyrich’s Odontopleura Brightii is a different species, and is
identical with Acidaspis quinquespinosa, Salter MS.

Acrpaspis coronata, Salter. (Pl. VII. fig. 6.)

. 1839. ? Paradoxides quadrimucronatus, Murch. ‘Sil. Syst.’ p. 658, pl. xiv. fig. 10.

1845. P Odontopleura mutica, Emmrich, Neues Jahrb. 1845, p. 44; 1846. Beyrich,
*Unters. tib. Tril.’ p. 19, pl. iii. ‘fie. 5.

1848. Acidaspis Brightii (oan), Salter, Mem. Geol. Surv. vol. ii. pt. i. p. 348,
pl. ix. figs. 8, 9 (not figs. 6, 7).

1853. ‘Acidaspis coronatus, Salter, Mem. ee Surv. dec. vii. pl. vi. p.7; 1854.
Morris, ‘ Catalogue of Brit. Fossils,’ 2nd ed. p

1854. Acidaspis Marklini, Angelia, ‘Pal. ee p. 38, pl. xxii. fig. 13.

1854. Acidaspis multicuspis, Angelin, ‘ Pal. Scand.’ p. 37, pl. xxii. fig. 12.
_ 1857. Acidaspis coronata, Salter, Quart. Journ. Geol. Soc. vol. xiii. p. 210.,

1885. Acidaspis Marklini, Lindstrom, Ofv. kongl. Vet.-Akad. Forh. Arg. 42,
no. 6, p. 54, pl. xii. figs. 8, 15, pl. xvi. fig. 10.

1888. Acidaspis mutica, Wigand, Zeitschr. deutsch. geol. Gesellsch. vol. xl. p. 93,
pl. x. figs. 19, 20.

General form broadly ovate, depressed. —

Head large, semilunar, the angles drawn out into broad spines 5
granulate. Glabella triangular; median portion nearly parallel-
sided; the basal lateral lobe is considerably larger than the second ;
poth are rounded and well-defined, but confluent on the inner side
with the median portion of the glabella; anterior lateral lobes
obsolete. Frontal border nearly straight, smooth, projecting beyond
the margin of the free cheeks. The facial suture in front of the eye
is nearly parallel to the axis, behind the eye is continued almost at
right angles, and cuts the posterior margin not far from the genal
angle. Eyes small, prominent, placed far back, close to the occipital
furrow; ocular ridge curved. Free cheeks easily separable, granular,
steeply inclined, bearing at the margin a row of about twelve short
spines; produced at the genal angles into broad spines, the borders
of which are nearly continuous in direction with the borders of the
cheeks.

The thorax consists of ten segments. Axis narrow. Pleure
straight, at right angles to the axis ; produced into spines, which are
strongly bent backwards. ach pleura bears a prominent ridge, on
which is a row of small tubercles, sometimes indistinct. The spines
also are granulate.

Tail broad, short. The axis consists of two segments. From the
anterior ring a strong rib proceeds on each side to the margin,
where it is produced and forms a primary spine. There are four
secondary spines between the two primaries, and one outside each.
All the spines are directed straight backward, and they are gene-
rally short. The margin, spines, and other prominent parts bear
tubercles, and there is generally one somewhat larger than fa
average, at the base of each spine. .

Horizons and Localities—Wenlock Limestone + Dudley ; Walsall ;
Malvern; Pen-y-llan, Cardiff. Lower Ludlow: Vinnal Hill, Ludlow;
Dudley. A very much crushed specimen in the Museum of Practical

238 MR, P, LAKE ON THE BRITISH © [May 1896,

Geology, Jermyn Street, from the Upper Llandovery of Pen-y-llan,
seems to belong to this species.

A ffinities.—This species closely resembles A. deflewa, from which,

however, it may be distinguished by the following characters :—
(1) the external border of the genal spine in A. coronata forms a
curve nearly continuous with the external margin of the cheek ; in
A, deflexa there is a distinct angle between the two; (2) the tail of
A. coronata bears eight short points, all of which are parallel to the
axis, while the tail of A. deflewa bears only four spines and a rudi-
mentary point at each of the anterior angles.
_ Synonymy.—A. coronata has been one of the most unfortunate
species of an unfortunate genus. At the present day it bears three
distinct names, all of which are in common use. It is known as
A. coronata in England, A. Marklini in Sweden, and A. mutica in
Germany; and even yet it is not clear which of these names it
ought to bear. Murchison’s term guadrimucronatus is older than
any of them; but it is so entirely misleading, and his description is
so incorrect, that although his figure is just recognizable, the name
can scarcely stand. Moreover, it is possible that all paleontologists
may not consider Murchison’s figure unmistakable.

The oldest of the other three names is mutica; but although our
Species is identical with A. mutica as figured and described by
Wigand, it is by no means certain that it is the same as Odonto-
pleura mutica of Emmrich and Beyrich. Emmrich’s description is too
brief to be of any value; but Beyrich’s account of the species states
that the thorax has only 9 segments, while in his figure the spines
of the tail are radiate instead of parallel. Until, therefore,
Emmrich’s or Beyrich’s type has been re-examined, it is impossible
to apply the name to the English form.

In 1848 Salter figured and described Acidaspis Brightu, Murch.,
but unfortunately, along with a specimen of the true A. Brighti, he
figured also a head and a tail of our present species. In 1853 he
had discovered his mistake, and proposed the name coronatus for the
new form, pointing out at the same time which of his figures
belonged to it; but it was not till 1857 that he published a
description.

In the meantime Angelin had described and figured the thorax
and tail of the same trilobite as A. Marklini, a name which has not
unnaturally been accepted in Sweden. Under the impression that
it belonged to a distinct species, he gave to the head of this form
the name of A. multicuspis. Angelin’s figures are not good, but
Lindstrom has since given an accurate description of the species with
good figures; and from an examination of the original specimens in
the Riksmuseum at Stockholm I am able to state that the Swedish
and English species are identical.

Thus there is plenty of room for difference of opinion, aa it is
not without hesitation that I have adopted Salter’s name. But,
putting aside Murchison’s term, Salter’s was the first which was
applied to a recognizable figure of the species,

Vol. szup | SILURIAN SPECIES OF ACIDASPIS. 239

AcIDASPIS DEFLEXA, sp. nov. (Pl. VII. fig. 7.)

This resembles A. coronata so much that a full description is
unnecessary, and it will be sufficient to draw attention to the chief
points of difference.

Head as in A. coronata; but the genal spines are more slender,
and their outer borders make a distinct angle with the external margin
of the cheek.

The thorax consists of ten segments, as in A. coronata ; but the
pleural spines are somewhat more delicate.

Tail rather large, broad. Axis small, with two rings defined
upon it; from the anterior ring a rib curves back on each side, and
is produced beyond the margin of the tail as a long slender spine,
slightly inclined outwards. Between these two primary spines are
two shorter ones, and outside each primary is a rudimentary point.

Horizon and Localities—Wenlock Limestone: Dudley ; Walsall.

Affinities—This is one of the forms which are commonly called
A. crenata in England ; but it is quite a distinct species, and is much
more closely allied to A. coronata. From A. crenata it is distinguished
by the outline of the head, the strength of the genal spines, the
absence of crenation on the frontal border, etc. From A. coronata
it is separated by the characters of the genal spine and of the tail,
as described above.

ActpasPIs cRENATA, Emm. sp. (Pl. VII. figs. 1 & 2.)

1845. Odontopleura crenata, Emmrich, Neues Jahrb. 1845, p. 44.
4 ew Ceraurus crenatus, Lovén, Ofv. kongl. Vet.-Akad. 1845, p. 47, pl. i.
eb.

Body oval, broad in front, narrowing rapidly behind.

Head sub-quadrate, about twice as broad as long, margin incurved
in front. The glabella narrows slightly towards the front ; basal and
second lobes rounded, nearly equal in size, almost completely cut off
from the central part of the glabella. The occipital ring bears a
small tubercle. Frontal border crenate. Facial suture in front of the
eye nearly parallel to the axis, behind the eye it cuts the posterior
margin. Eyes very prominent, placed far back, close to the neck
furrow and near to the glabella. Free cheeks granular; margin
provided with short spines ; genal angle produced into a long slender
spine, which at its origin is curved outward.

The thorax consists of nine segments, which after the first two or
three decrease in width towards the tail. Axis about as wide as the
pleure. Pleure nearly at right angles to the axial line; each bears
a prominent ridge, which, except in the case of the first two segments,
is produced into a long, slender, backwardly-directed spine.

The tail exists in two forms (each of which has been found
attached to a complete specimen) :—(1) very small; consists of two
segments, the anterior of which is produced backward into a long
spine on each side; two very short spines between these primaries ;
(2) much broader, with a broad flat area around the axis; primary
spines not so long, secondary spines larger. These two forms prob-
ably belong to different sexes.

240 _ MR, P, LAKE ON THE BRITISH ° [May 1896,

Horizon and Locality.— Wenlock Beds: Dudley.

Affinities—As already remarked, -A. defleva has usually been mis-
taken for A. crenata; but the resemblance i is not very striking, and
the differences have "already been noted. A. Barrandei, Ang., 1s
very close to A. crenata, and indeed is only distinguished by the
presence of a pair of tubercles on each ring of the axis and on each
pleura. Several of the British specimens show tubercles upon the
axis and pleure. ‘The presence or absence of these tubercles is
probably not a character of specific value, and depends, in part
at least, upon whether the actual test of the animal is preserved.
_ The specimens of A. crenata in the Riksmuseum at Stockholm
show both forms of tail. Lovén’s figure belongs to the narrow-tailed
variety.

AcIDASPIS QUINQUESPINOSA, Salter MS. (PI. VII. figs. 3 & 4.)

1846. Odontoplewra Brightii, Beyrich, ‘ Unters. tb. Tril.’ p. 20, pl. ii. fig. 6.
1854. Acidaspis quinquespinosus, Fletcher & Salter, in Magiaa: Catal of
Brit. Fossils,’ 2nd ed. p. 99; 1873. Salter ‘ Cat. Cambr. & Sil. Foss.’ p. 134.

Body broadly ovate.

Head short, broad, nearly straight in front; surface tuberculate.
Glabella triangular, occupying at the base about one-third the
width of the head; three pairs of lateral lobes separated one from
another by lateral furrows, but not cut off from the median part of
the glabella. The facial suture, represented by a raised ridge, runs in
a straight line from the anterior margin to the eye and thence in a
sigmoid curve to the genal angle. Eyes small, set somewhat behind
the middle of the cheeks; a straight ocular ridge runs from each
to the anterior corner of the glabella. Fixed cheeks broad, the
portion between the ocular ridge and the glabella tumid. Free
cheeks with a raised margin, which bears a row of short spines;
produced at the genal angle into a short curved spine. Axial part
of occipital ring broad, and bearing on its posterior margin five
‘small spines; the posterior margins of the cheeks each bear two
spines, exclusive of that at the genal angle.

The thorax consists of ten segments, and is broader than it is long,
‘Axis very broad, more than one-third the total width. Pleure
horizontal till near the margin, when they are abruptly bent down-
ward and then produced into short curved spines; the anterior
pleure are at right angles to the axial line, the posterior pleure
slightly inclined backward, and this is true, in a more marked
degree, of the spines, Each pleura bears a prominent tuberculate
ridge. |

Tail short, broad, forming a segment of a circle; it: bears one
curved ridge on each side, which is produced to form a short
primary spine. Outside each primary spine are two secondaries ;
and between the primaries are four secondaries. Margin of tail
raised.

Horizon and Locality— Wenlock Limestone: Dudley.

It is on the authority of specimens in the Woodwardian

Voli: 52. 41 i SILURIAN SPECIES OF ACIDASPIS. 241

Museum, referred to in Salter’s ‘Catalogue,’ that the name is
applied to the spevics here described.

Acrpaspis Barranbet, Fletcher & Salter, non Angelin. (Pl. VIII.
figs. 1-3.)

1848. Acidaspis bispinosus, Salter, Mem. Geol. Surv. vol. ii. pt. i. pl. ix. fig. 4
es Acidaspis Barrandii, Fletcher (dixit Salter), Mem. Geol. Surv. dec. vii.
p. 6, pl. vi.; 1854. Fletcher & Salter, in Morris’s ‘Catalogue of Brit. Fossils,’ 2nd ed.
p- 98; 1859. Murchison, ‘Siluria,’ 3rd ed. p. 261, Foss. 64, fig. 9.

General form quadrate, nearly as wide behind as in front.

Head quadrate, widest in front, tuberculate. Axal furrows almost
obsolete; median portion of glabella swollen, narrows slightly
towards the front; two pairs of lateral furrows deeply impressed ;
lateral lobes very indistinctly separated from the cheeks. Facial
suture invisible. Eye small, prominent, set in the middle of the
cheeks ; ocular ridge straight. Fixed cheeks large and tumid. The
free cheeks widen out towards the front, with a broad tuberculate
raised margin bearing a row of short spines. Moderately long
slender spines at the genal angles. but these do not appear to spring
from the margin. The axal part of the occipital ring is produced
into a pair of spines directed backward and outward.

The thorax consists of ten segments. Axis wide; each segment
bears two prominent tubercles. Pleure broad, flat, tuberculate ;
at a distance from the axis about equal to the width of the axis, all
but the last are abruptly bent downward and produced into a short
ornamented spine (very rarely visible); and from the angle of the
bend long horizontal spines are given off. The horizontal spines
are arranged in a radiate fashion, those from the anterior segments
being directed slightly forward, and those from the posterior
segments backward. The last segment differs from these, and
bears two ornamented horizontal spines on each side.

Tail broad, tuberculate ; axis ill-defined. The margin bears five
longer spines, one being median, and from the front of the base of
each lateral spine is given off a smaller ornamented spine, thus
making a total of nine.

Horizon and Localityn—Wenlock Limestone : Dudley, Callow
Farm.

Affinities —A. Barrandet is closely allied to A. Verneuili, Barr.,
and A. vesiculosa, Beyr., and in fact is chiefly distinguished by the
characters of its tail. A. vestculosa has five spines to its tail,
A. Verneuili seven, and A. Barrandei nine.

A. bicuspis, Ang., belongs to the same group. Only one specimen,
which is now in the Riksmuseum at Stockholm, appears to have
been found, and it is scarcely perfect enough to allow of one’s
asserting with confidence whether it is a distinct species or not.

Synonymy.—The head of this species was originally figured by
Salter in 1848 under the name A, bispinosus. In 1853 he corrected
his mistake, and stated that the form had been named A. Barrandii
by Fletcher, and would shortly be described. Since then this name
has been in common use in England; but no description seems

242 _ MR. P. LAKE ON THE BRITISH [May 1896,

ever to have been published. Unfortunately, in 1854, Angelin
adopted the name A. Barrander for a species quite distinct from
this, and allied to A. crenata. As, however, Fletcher’s name. had
already been published and applied to a definite figure, it would
appear to have priority.

Acrpaspts Hueuest, Salter MS. (PI. VIII. figs. 4 & 5.)
1873. Acidaspis Hughesii, Salter, ‘Cat. Cambr. & Sil. Foss.’ p. 93.

General form depressed, broadly ovate.

The head forms a transverse semi-oval. The glabella consists of a
parallel-sided median portion and two lateral lobes on each side,
completely cut off from the median portion ; the basal lobe is much
the larger. ‘The facial suture cuts the posterior margin just within
the genalspine. Eyes small,set somewhat far back. Fixed cheeks
narrow, tumid. Free cheek broad, granulate, provided with a raised
margin bearing a row of spines, which become longer towards the
genal angle; genal angle produced into a short weak spine directed
backward and outward. The axis of the neck-segment bears two
short spines, which are seldom visible.

The thorax consists of nine segments, and is of nearly equal width
throughout. Axis narrow, about one fourth the total width of the
body. Pleure straight; the greater part of each is occupied by a
broad prominent ridge, which bears a row of some half-dozen
tubercles ; on each side of this main ridge is a very narrow band,
the anterior one being somewhat the broader, slightly raised and
finely tuberculate. Both the central and the anterior ridges are
produced into spines, those from the former being considerably the
longer. These spines curve backward and increase in length
towards the posterior end of the body.

Tail broad, granulate. The axis consists of two rings and a
terminal knob, the second ring being often very indistinct. The
margin bears a row of radiating spines, namely :—2 larger spines
connected with the axis by a rib; 4 smaller ones between these ;
and 4, or perhaps 5, outside each of tue larger spines.

Horizons and Localities.—In the Jermyn Street Museum there are
specimens of this species from Brownthwaite, Gale Garth, Casterton
Low Fell, and Ravenstone Dale. The last three localities are referred
to the Upper Coldwell Beds by Mr. Marr,’ who also records the species
from the same beds at Helm Knot. In the Woodwardian Museum
there are specimens collected by Prof. Hughes from beds above the
Nant Glyn Flags at Pont Lawnt in Denbighshire, which he believes
to be on the same horizon as the beds of Casterton Low Fell.?

The specimen on which Salter is stated to have founded the
species was brought from Casterton Low Fell, and is now in the
Woodwardian Museum.

In the Jermyn Street Museum there is a specimen of Acidaspis
which is stated to come from the Llandeilo Flags near Pencerrig

1 Geol. Mag. 1892, p. 538.
2 Proc. Chester Soc. Nat. Sci. & Lit. pt. iv. 1893, p. 154.

Vol. 52.] SILURIAN SPECIES OF ACIDASPIS. 243

House, Builth. So far as can be seen, and the specimen is nearly
complete, it is indistinguishable from A. Hughesi; but it is difficult
to believe that this species can occur so low down in the geological
scale. Pencerrig lies close to the boundary between the Wenlock
and Llandeilo Beds, and it is possible that the specimen may have
been obtained from the former.

AcrpasPis ERINACEUs, Marr & Nicholson.

1888. Acidaspis erinaceus, Marr & Nicholson, Quart. Journ. Geol. Soc. vol. xliv.
p. 723, pl. xvi. figs. 11 & 12.

This species haying been recently figured and described, the only
point to which it is necessary to call attention here is that the
original of Messrs. Marr and Nicholson’s fig. 11 shows, somewhat
indistinctly, the frontal border in front of the glabella. The free
cheeks are lost in the specimens, and hence the form of the head,
with the glabella apparently projecting in front, seems abnormal
in the figure.

The species is compared by Marr and Nicholson with A. centrina,
Dalm., from the same horizon in Sweden.

Horizon and Locality.— Llandovery Beds: in the Acidaspis
erinaceus-zone of the Stockdale Shales at Torver Beck.

AcIDASPIS CALLIPAREOS, Wyv. Thomson.

1857. Acidaspis callipareos, Wyv. Thomson, Quart. Journ. Geol. Soc. vol. xiii.
p- 208, pl. vi. figs. 11, 12 ; 1878. Nicholson & Etheridge, ‘ Mon. Sil. Foss. Girvan,’
p. 125.

Only the head is described by Wyville Thomson; and it is
believed by Nicholson and Etheridge to be probably the head of
A. hystrix. The two, however, are stated to have been found on
different horizons. Wyville Thomson considers A. callipareos to be
very closely allied to A. pectinata, Ang.

Horizon and Locality. — According to Wyville Thomson, the
specimens were found in the Mullock Hill Sandstone near Girvan.
This is of Llandovery age.

Two other species, to which Fletcher and Salter! gave the names
of Acidaspis Dama and A. dumetosus, are stated to occur in the
‘Upper Silurian’ at Dudley. No description of them has been
published ; and I have been unable to find, in the various collections
arranged by Salter, any specimens ascribed to A. dumetosus. In
the Jermyn Street Museum several fragments from various horizons
are referred to A. Dama, but they are not sufficient to afford a
sound basis for the description of the species. The specimens from
the Wenlock Shale show a pair of spines springing from the neck-
segment, and are clearly distinct from any of the forms here
described.

1 Morris, ‘ Catalogue of Brit. Fossils,’ 2nd ed. (1854) p. 99.

Q.J.G.S. No. 206. s

244 _MR. P. LAKE ON THE BRITISH © [May 1896,

III. Comparison WITH THE SwEDISH AND BoHEMIAN Favnas.!

If we compare the British Silurian species of Acidaspis with
those from the same beds in Bohemia and Sweden, we arrive at
some interesting results. The following table includes all the
species which have yet been described from the Silurian of Sweden *
and Britain, and also those from Bohemia which are nearly allied
to any of the Swedish or British forms. There are, however, -
numerous Bohemian species besides these.

In the table the species which are closely allied to each other are
placed upon the same horizontal line, so as to show the amount of
resemblance between the three faunas :—

SWEDEN. BRITAIN. Bouwemtia.
A, Brighti. A. Grayi.t
A. bicuspis.* A. Barrandei, F. & 8S. A, vesiculosa, ete.
A, crenata; A. Barran- | A. crenata.
dei, Ang.
A. coronata(=A.Mark- | A. coronata.t
lint).
A, centrina. A, erinaceus.
A. pectinata. A. callipareos.t
A, doflexa.
A, quinguwespinosa.§
A, Hughesi,

A. cornuta.t
Numerous other species. .

* Only a single fragment of A. bicuspis appears to have been discovered.

t I have had no opportunity of examining these species.

+ dA. coronata occurs in Germany, but only in the boulders of the Glacial
deposits, and these have probably come from Sweden.

§ The specimen of A. guinquespinosa described by Beyrich under the name
A. Brightit came, not from Bohemia, but from Ludlow.

So far, then, as this comparison goes, two species from the
British Silurian are represented by closely allied forms in Bohemia,
and five in Sweden. There is but one Swedish species represented
in Bohemia, of which only a single specimen is known; and, on
the other hand, there is only one which is not represented in Britain.
lastly, there are more species of -Acidaspis in the Silurian of
Bohemia than in the Silurian of Sweden and Britain put together.

These results are suggestive, but they are no more. Until a
larger number of species has been examined, it would be rash to draw

» T have to thank Prof. Lindstrém for permission to examine the magnificent
series of trilobites in the Riksmuseum at Stockholm, and for much kind assist-
ance.during my stay in that city.

2 See Prof. Lindstrém’s ‘ List of the Fossil Faunas of Sweden,’ edited by the
Palzontological Department of the Swedish State Museum (Natural History),
pts. i. & 11. Stockholm, 1888. The two species A. centrina and A. cornuta from
the upp2r ‘ Brachiopod Schists’ are included, since those beds seem to contain a
certain number of Llandovery forms.

oa fe

Quart. Journ.Geol Soc. Vol. LI. Pl. VI

BRITISH. ACIDASPIS

Edwin Wilson. Cambri dge

BRITISH

Quart. Journ.Geol.Soc. Vol. LI] P]

AG TA i

Edwin Wilson. Cam bridge

Vol. 52.] SILURIAN SPECIES OF ACIDASPIS, 245°

any conclusions. So far, however, as the genus Acidaspis is con-
cerned, it appears that the British Silurian fauna is intermediate
between those of Sweden and Bohemia, but more closely allied to
the former.

EXPLANATION OF PLATES VII. & VIII.

Puate VII.

Figs. 1 & 2. Acidaspis crenata, Kmm., sp. Wenlock Beds, Dudley. British
Museum (Nat. Hist.). 1. Broad-taiied form, X 2. 2. Narrow-tailed
form, Xx 2.
3 & 4. A. guinquespinosa, Salt. 3. Entire specimen, deprived of its test.
Wenlock Limestone, Wren’s Nest, Dudley. Brit. Mus. Nat. size.
4, Head, with test preserved. Wenlock Limestone, Dudley. Fletcher
Collection, Woodwardian Museum. X 24.
Fig. 5. A. Brighti, Murch. Head. Wenlock Limestone, Dudley. Fletcher
Coll., Woodw. Mus. xX 14.
6. A. coronata, Salt. Wenlock Limestone, Dudley. Museum of Practical

Geology, Jermyn Street. x 2.
7. A. deflexa, sp. nov. Wenlock Shale, Dudley. Brit. Mus. x 2.

Puate VIII.

Figs. 1-3. Acidaspis Barrandei, Fletch. & Salt. Wenlock Limestone, Dudley.
Fletcher Coll., Woodw. Mus. 1. The most complete specimen known ;
anterior and posterior segments partially concealed. Nat. size.
2. Specimen showing internal view, with all the thoracic segments
displayed. Nat. size. 3. Head, showing occipital spines. xX 14.

4,5. A. Hughesi, Salt. 4. Salter’s type. Casterton Low Fell. Woodw.
Mus. xX 2. 5. S. of Gale Garth, Custerton. Mus. Pract. Geol. x 2.

Discussron,

The Prestpent said that the Author was pursuing the only safe
method possible at the present day when working at any special
group, namely, to visit the Museums and localities abroad where
such specimens are to be studied. Mr. Lake had already visited
Sweden, and hoped to study the trilobites of Bohemia. His work
would be very welcome to all paleontologists.

Mr. Marr remarked that the Bohemian beds lying between the
Ordovician and Devonian were not very rich in trilobites, except
those of Upper Ludlow age. He asked whether Acidaspis erinaceus
was closely related to A. centrina, and whether the latter was
considered identical with A. granulata. He was glad to find that
A, Hughesi was at last described. Two entirely different species,
one Silurian and one Devonian, had been named A. Hughes:, with the
result that in future fossil lists 4. Hughes: will probably be recorded
as a form passing from Silurian to Devonian.

The Avrnor replied that Aczdaspis granulata, Ang., was gene-
rally looked upon by Swedish paleontologists as a synonym of
A. centrina, Dalm.

s 2

246° MR..C. W. ANDREWS ON THE stRUCTURE [May 1896,

12. On the Srrucrurs of the PrestosavRian Sxutt. By Cuaries W.
_ Anprews, Esq., B.Se., F.G.S. (Read February 26th, 1896.)

[Puate IX.]

THE structure of the skull of the Liassic Plesiosauria has been
discussed by many writers, but the various accounts that have been
given of it are incomplete, and often differ one from the other in
important particulars, doubtless owing to the fact that in most
cases the specimens examined are much crushed, and are embedded
in the matrix, so that only one aspect is visible. In the National
Collection there is, however, a fine skull of Plesiosaurus macro-
cephalus, which has lately been almost completely cleared from the
matrix, so that it exhibits both the upper and under surfaces ; this
specimen, though it has been subjected to a slight vertical com-
pression which has caused some fractures and dislocations, gives a
fairly clear idea of the general arrangement of the constituent bones,
and, since it throws light on some obscure points, seemed worthy
of the following brief notice. Certain other specimens, which are
of assistance in some difficulties, will also be referred to.

- In 1838 Owen’ figured and described the upper and lateral regions
of the skull of P. macrocephalus, and in 1881 Sollas? described under
the name P. brachycephalus some portions of the head of a specimen
probably referable to the same species. Neither of these writers
had an opportunity of examining the palate, and it is this region,
therefore, that is more particularly considered here; while, in the
structure of the rest of the skull, only such points are noticed as
seem to add to, or to be at variance with, the descriptions already
published.

The specimen (Pl. IX.) under consideration is from the Lias of
Lyme Regis, and was referred to Plesiosaurus macrocephalus by
Mr. Lydekker.* The occipital surface is still somewhat obscured by
adherent matrix, and has the anterior cervical vertebre attached to
it, although the atlas has been dislocated from its articulation with
the occipital condyle.

The bones of the palate (Pl. IX. fig. 1), though somewhat dis-
placed from their natural positions, are, with the exception of the
transverse bone, fairly well preserved and distinct, so that their
form and relations ean easily be made out. .

The basioccipital (6.0c.) bears the whole of the nearly hemi-
spherical occipital condyle, and carries on either side a stout,
outwardly-directed tuberosity, the truncated end of which looks
outward. In the Plesiosauria the whole of these tuberosities
is formed by the basioccipital, but in most pa: the basisphenoid
enters into their composition.

1 Trans. Geol. Soc. ser. 2, vol. v. pt. ili. (1840) pl. xlv.
2 Quart. Journ. Geol. Soe. vol. xxvii. (1881) pl. xxiv. fig. 1.
: Eat, Foss. Rept. Brit. Mus. pt. ii, (1889) p. 368, no. 49202.

Vol.'g2.]).° OF THE PLESIOSAURIAN SKULL, 247.

The palatal surface of the basisphenoid (6.sph.) rises abruptly
from the basioccipital; it is slightly concave from side to side,
and is sharply separated from the lateral surfaces, which make an
angle of from 100° to 120° with it. The posterior portion of these
lateral surfaces forms a facet, looking outward and downward, with
which the pterygoid articulates. The basisphenoid seems to have.
been overlapped by a parasphenoid (pas.), but the hinder border
of that bone is indistinguishable; anteriorly it expands into a thin,
spearhead-shaped plate, the outer angles of which in the present
specimen overlap the ventral surface of the pterygoids, and with
them limit the posterior palatine foramina (post.pal.vac.),’ which.
open between the basis cranii and the pterygoids, as in Peloneustes..
In this latter, however, the parasphenoid is slightly overlapped on
its ventral surface by the pterygoids ; this difference in the relative
position of the bones in the two genera may be due to displacement
in the present specimen.

The pterygoids (pé.) are triradiate bones, like those of Pelo-
neustes, but differ from them in not meeting in the median line
over the basisphenoid, and remaining separated by the whole palatal
width of that bone. Anteriorly they have been dislocated from their
junctions with one another and the surrounding bones, but there
can be no doubt that in their natural position they met anteriorly
and, together with the parasphenoid, closed the palate in the middle
line.

Their anterior rami are thin triangular plates, the apices of which
meet the vomers, while their inner borders form a median suture
with one another in front, and are overlapped by the parasphenoid
behind. In the uncrushed skull their outer edges united with the
palatines. |

The lateral rami run outward opposite the anterior end of the
posterior palatine foramina; their outer ends are much thickened
and in the present specimen have been partly broken away. In the
skull of P. dolichodeirus noticed below (fig. 1, p. 248), the outer ends
of these lateral rami are joined to the maxillary region by a transverse
bone (trs.), and the same is the case in Péeloneustes and Pliosaurus.

In front the posterior rami are narrow bars of bone forming the
outer border of the posterior palatine foramina. Behind these
openings they widen a little, and bear on their inner side facets for
articulation with the corresponding surfaces on the sides of the
basisphenoid. Posteriorly they run outward and backward as
thin vertical plates to the quadrates, which do not appear to send
forward to meet them plates of bone such as are seen in Sphenodon.

The columella cranvi (Pl. IX. fig. 4, col.) or epipterygoid is well

‘ In this paper, as well as in that on the skull of Pe/loneustes (Ann. Mag.
Nat. Hist. ser. 6, vol. xvi. 1895, p. 242), the term ‘ post-palatine foramen’ is used
in a different sense from that in which it is sometimes employed (for example, by
K. T. Newton in his papers on the Reptilia of the Elgin Sandstones), end is
applied to the pair of Beantine which result from the division of the median
interpterygoid foramen by the basisphenoid and parasphenoid. Newton employs
the terin for the aperture which lies in front of the transpalatine, and is here
called the ‘ suborbital foramen.’

248 - MR. C."W. ANDREWS ON THE STRUCTURE [May 18969

shown in this specimen. It rises from the upper surface of the
pterygoids about opposite their junction with the basisphenoid ;
its base of attachment is very long from before backward, so that
it extends for a considerable distance along the upper edge of the
quadrate process of the pterygoid. In its middle portion it con-
tracts in width, and is an elongate oval in section. On both sideg
of the skull the upper portion of this bone has unfortunately been
broken away, so that the junction with the parietals is not clear,,
but it evidently joined their lower edge at about their middle point.
The palatines ( pal.) are elongated plates of bone, of which the
anterior edges form the hinder margin of the nares; on the inner
side they unite in front with
the vomers, and behind with Fig. 1.—Palatal surface of the Skull
the pterygoids, while on the of Plesiosaurus dolichodeirus.
outer they join the maxille. (About 3 natural size.)
In the present specimen the |
relations of the hinder border
of the palatine are not clear,
though it is evident that in-
ternally it joined the lateral
ramus of the pterygoids;
but in a skull of P. dolicho-
deus (B.M. Coll. 41101)
it can be seen (fig. 1) that
externally the hinder border
of the palatine joined the
transpalatine for a short
distance, and was then
separated from it by a
small suborbital foramen
(sub-orb.var.) which appears
to be closed on its outer
side by the maxilla. Mr.
Lydekker ' first called atten-
tion to these foramina in this
specimen (fig. 1), in which
also he first observed the fact
that the pterygoids extend
forward to meet the vomers.
The vomers (vom.) are bP
not well preserved; they he
are long narrow bones which <i
unite, and perhaps anchylose,
in the middle line. Posteriorly they join the pterygoids, and in
front of these, the palatines. About the middle of their length
they form the division between the internal nares, and anterior
to ag apertures they run forward between the maxilla and pre-
maxille

* Cat. Foss. Rept. Brit. Mus, pt. ii. (1889) p. 257, no. 41101.

Vol. g22}: : OF THE PLESIOSAURIAN SKULL. 249

- The lower surface of the maxille and premaxill is largely
concealed by the mandible, which is tightly closed upon them. ‘lhe
inner border of the palatal plate of the maxilla is, however, visible
for some distance both in front of and behind the internal nares, the
outer border of which it forms. In its anterior region there are
one or two pits which probably mark the points of eruption of
successional teeth. ‘he palatal portion of the premaxille is almost
completely concealed by the symphysial region of the mandible ;
but the anterior ends of the vomers appear to run forward some
distance between these bones; in the above-mentioned skull of
P. dolichodeirus this is certainly the case (fig. 1, p. 248).

The general structure of the Plesiosaurian palate is shown dia-
grammatically in fig. 2 (p. 251).

The structure of the temporal arcade (Pl. IX. fig. 3) is, in
all essential respects, similar to that in Plescosaurus brachycephalus
(figured by Sollas),’ P. dolachodeirus, and P. Hawkinsi (figured by
Owen), and also to that of Peloneustes *: the only important difference
being that in the present species the postorbital sends back a long thin
strip along the anterior ramus of the squamosal nearly to its origin.
The supra-jugal which Sollas observed in P. brachycephalus cannot
be detected, but, if I understand the description of that bone (it is not
figured), it corresponds to the lower portion of the postorbital. The
thin posterior extension of the maxilla along the lower edge of the
jugal is concealed by the mandible, the pressure of which has driven
it inwards.

’ The wall of bone described by Sollas, which separates the orbit
from the temporal fossa, is well shown in this specimen. It appears’
to be mainly formed by the postfrontal and postorbital, each of
which thus consists of an external facial and an internal postorbital
portion, which meet in the angle forming the anterior rim of the
temporal fossa. I cannot make out what share in the formation of
this postorbital wall is taken by the jugal; according to Sollas it is
an important one.

_ The upper ramus of the triradiate ‘ squamosal’ is in this specimen
indistinguishably fused with the remainder of that hone; but in the
younger skull described by Owen it is separated by a distinct suture,
which is figured by him.* He calls this upper portion the ‘ mastoid,’
while the remainder of the bone, consisting of the inferior and
anterior rami, is designated the ‘squamosal.’ It is clear that these
two elements are equivalent to the supra-temporal and squamosal of
lizards, according to the terminology of Parker & Bettany and
many other writers, or to the squamosal and prosquamosal, according
to Baur. Their arrangement is similar to that occurring in the
Rhynchocephalia, the fused elements of the older individuals having
almost exactly the form and relations of the so-called ‘ squamosal ’

? Quart. Journ. Geol. Soc. vol. xxxvii. (1881) pl. xxiv. fig. 2.
? Trans. Geol. Soc. ser. 2, vol. v. pt. iii. (184V) pl. xlv.

3 Ann. Mag. Nat. Hist. ser. 6, vol. xvi. (1895) p. 251, fig. 2.
* Trans. Geol. Soc. ser. 2, vol. v. pt. iii. (1840) pl. xlv.

250 MR. C..W. ANDREWS ON THE STRUCTURE [May 1896,

of Sphenodon. Koken! has expressed the same opinion as to the

constitution of the ‘squamosal’ in the Nothosauria. In several)

Plesiosaurian skulls in the British Museum the suture between
these elements is distinct.

The quadrate (q.) is a long, stout bone; posteriorly it is convex’
from side to side, anteriorly concave. It projects downward and

backward, and the condyle for the mandible lies somewhat below

the level of the alveolar border of the maxilla. On its outer side

the inferior ramus of the squamcsal is closely adherent to it, and
extends nearly down to the condyle.

In Cimoliosaurus Cope? has figured a small quadrato-jugal, and.

Koken * has recorded the probable occurrence of this bone in Notho-

saurus ; it therefore seems possible that the Plesiosaurian quadrate

may be a fusion of the quadrate and quadrato-jugal, a view which
derives some support from the fact that the relations of the

squamosal to the ‘quadrate’ are almost exactly similar to those

existing between the squamosal and the quadrato-jugal in Sphenodon.

The general structure of the upper surface of the skull is shown,

in Pl. IX. fig. 2. It will be seen that between the anterior halves
of the temporal fosse the parietals form a high, sharp crest, but that
posteriorly they widen out into a broad triangular plate, convex
from side to side, which apparently roofs in the brain-case. The
outer angles of this plate are overlapped by the upper rami of the

squamosals, these forming the hinder border of the temporal fossa.
In front, opposite the anterior end of these fosse, the parietals en--
close the pineal foramen, which does not extend into the frontals,
and laterally they widen out and take part in the formation of the.

postorbital wall. There is clearly a distinct post-temporal fossa,
closed above by the lateral process of the parietal and the upper
ramus of the squamosal. The frontals extend much farther forward
than in Peloneustes, and separate the external nares. I can find no
clear evidence of the existence of distinct nasals and lachrymals.

Comparison of the palatal portion of this skull with that of Pelo-
neustes shows that the chief difference between them is that in the
Jatter the pterygoids, instead of merely articulating with the sides
of the basisphenoid, overlap it, and form a median suture with one
another on its ventral surface. In Peloneustes, also, the form of the
parasphenoid is different, and it is very uncertain whether there is
any suborbital vacuity.

In Nothosaurus the pterygoids meet in the middle line from end
to end, and there is no suborbital vacuity, so that the palate is
completely closed ; this appears to be a more specialized condition

than occurs in either Plesiosaurus or Peloneustes, although both

these genera are of a later date. |

1 «Beitrage zur Kentniss der Gattung Nothosaurus, Zeitschr. deutsch. geol.
Gesellsch. vol. xlv. (1893) p. 363.

* *On the Structure of the Skull in the Plesiosaurian Reptilia,’ Proc. Amer.
Phil. Soc. Philadelphia, vol. xxxiii. (1894) p. 110.

3 Op, supra cit.

Vol. 52.] OF THE PLESIOSAURIAN SKULL. 251-

In Lariosaurus’ the palate is essentially similar to that of
Plesiosaurus, but here again: the pterygoids completely shut in the
basis cranit. The suborbital vacuity is very large, and the pterygoids
bear teeth, both probably primitive characters. The palate of
Neusticosaurus is doubtless similarly constructed, but the suborbital
vacuities are still larger.

In Pistosaurus the pterygoids appear to leave the basis cranii
exposed for some distance, and in this respect the palate in this
genus is more Plesiosau-
rian in form than is
that of any other Triassic
Sauropterygian.

Among reptiles other
than the Sauropterygia
the palate most similar to
that under consideration
is found in Sphenodon.
In this reptile the form
and the relations of the
bones of the palate to one
another and to the internal
nares are almost identical
with those above de-
scribed. The only differ-
ence of importance is that
the pterygoids, instead of
articulating directly with
the sides of the basisphe-
noid, are borne off from it
by downwardly -directed
basi-pterygoid. processes,
so that they come to lie at
a lower level than the
basis cranv. The conse-
quence of this arrangement is that the parasphenoid, here very
small, does not run forward between them dividing the interpterygoid
vacuity into two post-palatine foramina.

Too much importance must not be attached to the similarity
existing between the palates of these two forms, since the Rhyncho-
cephalian type of palatal structure occurs in a more or less modified
form in many widely divergent reptilian groups, and probably there-
fore approaches the primitive type of structure common to the
ancestors of those various groups. For instance, the [chthyosaurian
palate, except that the lateral wing of the pterygoid is reduced, and
the transverse bone consequently absent, is very like that of Sphen-
odon. Again, among the Anomodonts, Procolophon is, so far as
the palate is concerned, Rhynchocephalian ; the presence of teeth

Fig. 2.— Diagrammatic figure of the

Plesiosaurian palate.

- 1 For my knowledge of the structure of the palate in this genus I am indebted
to Mr. Boulenger, who kindly allowed me to see a proof of his forthcoming
paper on the skeleton of Lariosawrus Balsami.

252: MR. C. W. ANDREWS ON THE STRUCTURE [May 1896,’

on its pterygoids and vomers is probably a primitive character
derived from its Labyrinthodont ancestors; the palate of Pareia-
Saurus is similar,

In the Theriodonts a short secondary hard palate is developed,
carrying back the opening of the internal nares; but in some speci-
mens (for example, the skull of Galesaurus planiceps, B.M. R. 511)
the relations of the bones constituting the primitive palate are
Sphenodon-like, the pterygoids extending forward to meet the
vomers, and their lateral rami bearing a downwardly-directed
process (ectopterygoid) which lies against the inner side of the
closed mandible, and is no doubt partly formed by a transpalatine
element. There seems to be no suborbital vacuity.

The palatal structures of the Chelonia, regarded as modifications
of the same type, are easily comprehensible, and the same is the
case with the Lacertilia. In the highly specialized palate of the
Crocodilia, the resemblance to the primitive form is masked by the
secondary hard palate formed by the palatines and pterygoids ; but if
this be disregarded, the same type of structure may be traced here also.

Enough has been said to show that among reptiles a certain
similarity of palatal structure does not necessarily imply any close
relationship, but the very great resemblances existing between the
Plesiosaurian and Rhynchocephalian palates, reinforced by the
numerous other points of likeness in other portions of their skeletons
pointed out by Baur, lead to the conclusion that the Sauropterygia,
notwithstanding their single temporal arcade and thecodont denti-
tion, are descended from a primitive Rhynchocephalian reptile. This
opinion has already been expressed by several writers, notably by
_ Baur’ and Boulenger.’

EXPLANATION OF PLATE IX.

Skull of Plesiosaurus macrocephalus, Buckland,
Fig. 1. From below.
2. From above.
3. From the side.

4, Temporal fossa seen obliquely from the side, showing the relations of
the columella.

ang., angular. pas., parasphenoid.

b.oc., basioccipital. pin.for., pineal foramen
b.sph., basisphenoid. [misprinted pm.for.].

col., columella cranii. pme., premaxilla.

ext.nar., external nares. p.ord., post-orbital.

int.nar., internal nares, p.fr., pre-frontal.

Jr., frontal. ? post.fr., ? separate post-frontal.
gug., Jugal. post.pal.vac., posterior palatine
mx., maxilla. yacuities. ~

orb., orbit. g., quadrate.

pal., palatine. sg., squamosal,

par., parietal. vom., vomer.

All the figures are about + natural size.

+ *On the Phylogenetic Arrangement of the Sauropsida,’ Journ. Morph.
vol. i. p. 93. )

? Cat. Chelonians, Rhynchocephalians, and Emydosaurians in the British
Museum, p. 1. :

J.Green del. et lith. M -

, aes . z —— ; Mf a : Minternmn Dros. imp
Pool OF PLESIOSAURUS MACROCEPHALUS ,B cldand
, J 5+ JLAN i io © i

vt =

Cr OF THE PLESIOSAURIAN SKULL, 253

Discussion.

The PresipEnt invited discussion.

_ Prof. Howes, on behalf of morphologists, gave expression of
gratitude to the Trustees and Staff of the British Museum of
Natural History for the work now being accomplished in their
Geological Department. He remarked that he had been privileged
to examine the Author’s specimens, and that he fully confirmed
his determinations. He could not accept the idea, to which reference
had been made, that Pureiasaurus had a closed palate in the ordinary
sense ; that is to say, the internal nasal openings were not carried
to the back of the palate by the union of the palato-pterygoid bones
as they are in the Crocodilia.

In concluding, he pointed out that the Author’s determinations
of the bony palate of the Sauropterygia were in complete harmony
with Mr. Lydekker’s of that of the Ichthyopterygia, and with the
best-established facts of morphology; and that, thanks to these
gentlemen, we were now in a position to definitely refer the
‘ Enaliosauria’ to an origin among the lowest reptiles.

Mr. Lypexxer and Dr. Woopwaxp also spoke.

The AvurHor expressed his thanks to the Fellows, particularly
those who had spoken, for the kind manner in which they had
received his paper. He also referred to his indebtedness to Mr. Hall,
one of the ‘masons’ at the Natural History Museum, for the
skilful way in which he had cleared the specimen from its hard
matrix,

254 DR. H. HICKS ON THE MORTE SLATES, AND [May 1896,

13. On the Morte States, and Assoctatep Berns, in Nortna Devon
and WEstT Somerset.— Part I. By Henry Hicks, M.D., F.RB.S.,
P.G.S. (Read February 5th, 1896.) .

[Puatses X. & XI.]

ConTENTS.
Page
APY AmtrOduMebIOMs te .nateckncce-cacens cree ecsee i ptaascapr sce Secnitie se ss eee eee 254
IT. Morthoe and Woolacombe to Bittadon..............ssssssesececesnsacnesceas 257
III. Rockham Bay, Bull Point, Lee Bay, Lee, and Slade .................c00 261
TV? Mullacott, Sheliin, and Efracombe © .).225.2...20<.00.0000en eos seeene eae 262
V. Woolscott Barton, Smithson, and Berry Down. ...........-...seseeeeenees 264
VI. Summary of the Stratigraphical Evidence in North Devon ............ 264
VII. Description of the Fossils found in North Devon ............cceeeeseeees 266
Geological Map of the Ilfracombe and Morthoe Districts ............... 259

I. Intropuction.

Hituerto the Morte Slates have received but scant attention from
geologists, owing to the fact that in all text-books, and in geological
papers on North Devon, they have always been referred to as un-
fossiliferous ; and all that was known with regard to them up to the
year 1887 is well summarized in the following paragraph taken from
the second edition of Mr. H. B. Woodward’s well-known work, ‘ The
Geology of England and Wales,’ p. 127 :—‘ This division, termed the
Morte Slates by the Rev. D. Williams, derives its name from Morte
Point, on the north-west coast of Devon. The term Mortehoe Group,
from the village of that name, was used by John Phillips. The Morte
Slates, or ‘‘ grey slates,” comprise pale greenish-grey and silvery
grey glossy slates, much veined with quartz, and having a thickness
estimated at from 3000 to 4000 feet. No fossils have been found ;
nor have any limestone-bands been recognized in them. The beds
rest on the [Ilfracombe Beds at Lee Bay, and the subdivisions which
can be traced are noted by Mr. Etheridge (in ascending order) as
the Lee, Rockham Bay, and Morthoe Beds. The Morte Slates pass
downwards into the Ilfracombe Beds, and in Mr. Ussher’s opinion
they are simply an upper unfossiliferous portion of this lower
division, since it is impossible to fix any definite boundary between
them. Simonsbath is situated in the valley of the Barle, between
the Ilfracombe and Morte Beds. Eastwards they extend to near
Wiveliscombe, where they are exposed at the Oakhampton Slate
quarry, north of that town. ‘The slaty beds of Hestercombe, north
of Taunton, are probably on the horizon of the Morte Slates. The
valuable spathose iron-ore of the Brendon Hills occurs in these
beds.’

Vol. 52.| ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 255

On November 26th, 1890, I read a paper before this Society
‘On the Rocks of North Devon,’ in which I stated that during a
recent visit to North Devon not only had I found that the Morte
Slates were fossiliferous, but that I had come to the conclusion that
they were the oldest rocks in the area, and that they had, as the
result of movements in the earth’s crust, been brought to the
surface and thrust over much newer rocks, producing a deceptive
appearance of overlying the latter conformably.

As my views regarding the succession were strongly controverted
at the time, the paper was withdrawn, and I decided to re-examine
the area, and to carry my researches into other districts which I
had not previously had an opportunity of visiting. As this has
necessitated the spending of several weeks each year, since the paper
was read, either in North Devon or West Somerset, much additional
evidence bearing on the succession has been obtained; but in this
that relating mainly to the position and age of the Morte Slates will
be referred to.

The beds included under the term ‘ Morte Slates ’ are for the most
part much folded and highly cleaved, and the fossils are in con-
sequence frequently much distorted and in a bad state of preservation.
A considerable amount of labour and time has therefore had to be
expended on these rocks to obtain anything like a satisfactory
fauna. The results on the whole, however (when it is remembered
that up to 1890 these beds were always referred to as unfossili-
ferous), must be considered as highly important, since we are now
able by the aid of the fossils to define the age of a very con-
siderable portion, if not of the whole, of these beds. That they
must necessarily furnish the clue by which the succession in North
Devon is to be unravelled will, I think, be generally admitted.
Therefore, if their geological horizon can be settled the main
difficulties which have so long surrounded the ‘ Devonian question ’
in North Devon, and which have led to so much controversy in the
past, will virtually disappear.

In the geological map given in Mr. Etheridge’s very important
paper published in this Journal in 1867, the Morte Slates are shown
as extending continuously from Morte Point to near Wiveliscombe,
in West Somerset, a distance of over 40 miles. That rocks which
possess characters resembling in many ways the typical Morte Slates
are to be found all along this line there can be no doubt, but it
will be shown that, here and there, they vary much in appearance
and belong to different geological horizons. The strike of the
beds also changes, and is seldom quite parallel with the overlying
strata.

In my search for fossils in these rocks I have received invaluable
assistance from my friends the Rev. G. F. Whidborne, M.A., F.G.S.,
and Mr. J. G. Hamling, F.G.S., of Barnstaple. I have also to
express my indebtedness for special assistance with regard to some
of the fossils from Mr. Sharman and Mr. Allen, of the Museum of
Practical Geology ; Mr. Bather, of the British Museum (Natural

256 DR. H. HICKS ON THE MORTE SLATES, AND [ May 1806,

History); Mr. F. Cowper Reed, of Cambridge; Mr. J. Hopkinson,
and Prof, C. Lapworth.’

1 [A complete résumé of the literature of the North Devon rocks up to the
year 1867 has been given by Mr. Etheridge in his paper already referred to.
Up to the year 1868 the views put forward by Sedgwick, Murchison, Godwin-
Austen, De la Beche, and Phillips received general acceptance, but during that
and subsequent years Prof. Jukes suggested modifications which tended towards
a very different interpretation. In his paper in the Quart. Journ. Geol. Soe. in
1866, vol. xxii., he says at p.321: ‘As I shall have to maintain that all the first
geoloyists of the day, including Prof. Sedgwick, Sir R. I. Murchison, Mr. Weaver,
Sir H. De la Beche, and Prof. Phillips, have misunderstood the structure of the
country, let me hasten to avow my belief that nobody whose observations were
confined to Devon and Somerset could have arrived at any other than their con-
clusions. I fully admit that the rocks near Lynton appear to be the lowest, and
that there appears to be a regular ascending succession of rock-groups from
Lynton to the latitude of Barnstaple. J am, however, compelled to dispute the
reality of this apparent order of succession, and to suppose that there is either a
concealed anticlinal with an inversion to the north, or, what I believe to be
much more probable, a concealed fault running nearly east and west through
the centre of North Devon, with a large downthrow to the north, and that the
Lynton beds are on the same general horizon as those of Baggy Point and
Marwood.’

In 1867 Mr. Townshend M. Hall, whose researches have added so much to our
knowledge of the North Devon rocks and their fossil contents (Quart. Journ.
Geol. Soc. vol. xxiii. p. 371), subdivides the North Devon series, in ascending
order, as follows:—Foreland group, Lynton zone, Martinhoe beds, Ilfracombe
group, Morthoe group, Cucullea-zone, Pilton beds—and says: ‘ From the Fore-
Jand on the north to Barnstaple on the south the rocks have an almost uniform
dip to the south, usually at a high angle, presenting to all appearance an
unbroken succession.’

Mr. Etheridge, in his paper of the same year (op. cit. vol. xxiii. p. 568),
strongly controverts the views put forward by Prof. Jukes, and maintains that
the succession in North Devon is one unbroken and continuous series. He
subdivides the rocks in ascending order as follows (p. 580) :—

Lower { a. Lynton Sandstone. (Foreland Beds.)
Devonian. | 6. Lynton Slates.

Middle. { ¢: Hangman Grits.
Wevenisa d. Calcareons Slates (fossiliferous). (Ilfracombe Beds.)
oY ‘|e. Grey unfossiliferous slates. (Morte Slates.)
(f. Pickwell Down Sandstones.
| g. Baggy and Marwood Slates, etc.
Dapper 4%. Croydon [Croyde] Beds,
. | .

i. Braunton Beds.
\ &. Pilton and Barnstaple Beds,

He further says at p. 694: ‘ After very careful investigation into the physical
structure of North Devon, as well as a critical examination of the organie
remains contained in its diversified rock-masses, I can come to no other
conclusion than that the series of sandstones, slates, and limestones ranging
from the Foreland and Lynton on the north to Pilton and Barnstaple on the
south are one great and well-defined system, and equally well divisible into
three groups, a Lower, Middle, and Upper Devonian series, each equally well
characterized by a fauna, the zoological facies of which are sufficiently distinct
to determine them one from the other.’

The following appears to be the final arrangement suggested by Prof. Jukes ;
it occurs in a paper read before the Royal Geological Society of Ireland in

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 257

II. MortHor And WooracomseE To Birrapon.

The beds are well exposed at Morte Point and in the cliffs of
Rockham Bay on the northern side, and between the Point and
Woolacombe on the southern side. At the Point the beds are nearly
vertical, being folded so acutely that the bedding, owing to the
cleavage, is with difficulty made out. Under Morthoe, however, there
are some well-marked folds, and the strike is shown to be from about
W.S.W. to E.N.E. The folds are here, as in most places along this

November 1867, and is given in reply to the papers in the Quart. Journ.
Geol. Soe. of that year by Mr. Townshend Hall and Mr, Etheridge.

Southern Area. Northern Area,
5. Pilton and Barnstaple Beds. . Grey unfossiliferous slate. (Morte,)
4. Braunton Beds. . Caleareous Slates. (Ilfracombe.)
3. Croyde Beds. Hangman Grits.
2. Baggy and Marwood Slates. . Lynton Slates.
1. Pickwell Down Sandstones (red). . Lynton Sandstone (red).

Mm roc ROL

Prof. Jukes places the beds, as named by Mr. Etheridge, in parallel columns,
with the view of showing that the groups in the one area are merely a repetition
of those in the other.

Since that time the rocks have been investigated by Messrs. Valpy, Hall,
Champernowne, Ussher, and others; but no important change in the classifica-
tion suggested by Mr. Townshend Hall and Mr. Etheridge has been attempted
by them. In a paper on the ‘ History of the Classification and Nomenclature
of the North Devon Rocks,’ in the Trans. Devonshire Assoc. 1879, p. 189,
Mr. Townshend Hall says: ‘On the whole, as far as North Devon proper is
concerned, I believe the following classification is the best that can be adopted
for the Devonian beds :—

Upper

Nevouisn, Cucullea-zone (Baggy Point, etc.).

Pickwell Down Sandstone.

: Morthoe Slates.
aoe Ilfracombe Slates and Limestones.
evonian.

Martinhoe or Hangman Grits,

Lower { Lynton Beds.
Devonian. | Foreland Sandstones.’

And at p. 190, he says:—‘ It will be found that the North Devon Beds from
Lynton to Pilton, though possessing a general dip to the south, are folded into
many anticlinals, reducing their apparent thickness very considerably. I know
this to be the case at so many different places throughout the area that, until
we have a re-survey on the six-inch scale, I fear it will be a hopeless task to
attempt to map the exact boundaries of the subdivisions, or to estimate their
real thickness.’

In Sir H. De la Beche’s ‘ Report on the Geology of Cornwall, Devon, and
West Somerset,’ 1839, a section across the North Devon Beds is given (fig. 1,
pl. iii.) which shows several main folds ; and Dr. Sorby, in his well-known paper
‘On the Origin of Slaty Cleavage’ (Edinb. New Phil. Journ. vol. lv. 1853,
p. 1387), and Mr, J. E. Marr, in his important paper ‘On some Effects of
Pressure on the Devonian Sedimentary Rocks of North Devon’ (Geol. Mag.
1888, p. 218), have shown how the rocks in places have been greatly affected
and minutely folded and broken by pressure. See also Jukes, Quart. Journ,
Geol. Soc. vol. xxii. (1866) p. 371; Champernowne, Geol. Mag. 1878, p. 193;
Champernowne & Usher, Quart. Journ. Geol. Soc. vol. xxxy. (1879) p. 532
and Hicks, Geol. Mag. 1893, p. 3.—April 15th, 1896.]

Pilton Beds.

258 , THE MORTE SLATES AND ASSOCIATED BEDS. _—_[ May 1896.

coast, much broken, and the beds near the lines of fractures much
seamed with quartz-veins. All the beds are strongly cleaved, and
the cleavage-planes are either vertical or with a-slight inclination —
towards the south. There are, here and there, afew thin sandstone-
bands, but the majority of the rocks are hard, cleaved slates, and
flags of a greyish colour. Where the hard bands occur they are
usually much broken by the cleavage, and the broken fragments
frequently give to the rocks quite a nodular appearance,

The slates dipping at a high angle can be traced as far south as
the Lifeboat House, and also in the bed of the stream at the foot of
Challacombe Hill, to a height of about 100 feet. Above this the
ground rises rapidly, and a quarry which has been opened for
building-stone at a height of about 230 feet, and distant from the
last exposure of Morte Beds about 500 feet, shows massive purple,
red, and grey grits and sandstones folded and much broken. These,
and an exposure close by on Potter’s Hill, are the lowest of the
Pickwell Down Beds found on the coast, and as they are strongly
ripple-marked they must have been deposited in shallow water.
Still, their broken condition would indicate a faulted junction at
this point. In the quarry one dip is to S.S.E., another to $.8.W.,
and on Potter’s Hill to 8.S.E. at 40°. The Pickwell Down
Beds extend in an easterly direction, and may be again examined
in several quarries on the high ground between here and the
Foxhunter’s Inn, on the road from Ilfracombe to Barnstaple.
Opposite the inn, on the western side of the railway, there isa large
quarry, where very massive beds of sandstone are bent into gentle
folds, and on the northern side crushed and broken as if near a fault.

The Morte Slates are well exposed in the railway-cutting at
Willingeott Bridge, and also at Dean, which is about } mile
north of the Foxhunter’s Inn. At the latter place they dip
northward at about 70°, and differ somewhat in appearance from
those exposed at Woolacombe, because a large number of hard
bands of a finé-grained sandstone are interstratified with the
slates. In following the junction between the Morte Slates and
the Pickwell Down Beds up to this point, I could come to no
other conclusion than that a fault separated them, and that as a
consequence the same beds were very seldom in contact. Beyond
West Down, and at Bittadon, the indications of an important fault
between the Morte Slates and the Pickwell Down Beds are less
marked, and the latter dip to the south at as low an angle as 15°
near the inn at Bittadon. I searched carefully ats and about
Bittadon for evidences of a passage, but everywhere there appeared
to be a sudden change from highly-cleaved slates, dipping at a
high angle, to massive sandstone-beds with a low dip. It isa
marked characteristic of the Morte Series that they are mainly hard,
slaty, and flagey beds made from fine muds, and that the few sand-
stone-beds are composed of well-rounded grains of quartz in an
argillaceous matrix. When compared with the overlying rocks, the
almost entire absence of mica is somewhat striking.

The Pickwell Down Beds which, in this area, immediately succeed

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260 DR. H. HICKS ON THE MORTE SLATES, AND _—[ May 1896,

the Morte Slates, are characterized by containing angular bits of
slate, angular and subapgular quartz often stained of a red or
chocolate colour, and frequently a considerable amount of a fresh-
looking felspar. The sandstones and shales also contain an unusual
proportion of detrital mica. When it is remembered that these
beds often yield fossil wood, and are frequently ripple-marked, it
becomes clear that they were deposited under different conditions
from those which prevailed when the majority of the Morte Slates
were thrown down, and the evidence certainly points to an
important physical change taking place at no great distance about
this time.

I have not met with any contemporaneous igneous rocks in the
Morte Series, but there are a few intrusive dykes, one of the
most important being the felsite at Bittadon described by Prof.
Bonney.’ Others have been referred to by Mr. Etheridge and
Mr. Townshend Hall in Morte Bay, Lee Bay, ete.

The Morte Slates in this area yield traces of fossils in many
places, but none sufficiently well-preserved for identification,
excepting in the cliff-sections at Morthoe and Woolacombe. The
first fossil found by me was a Lingula at Woolacombe in 1890;
but since then several additional genera have been discovered at

Fig. 1.—Section from near Morthoe to Woolacombe.

above |
Crunta Beach .
Woolacombe ~
above Barricane ‘Beach Sands

S

NW \\ \

Y
NY
N

Zz
Le Ee
ee aw oe ee ee

AN

[Horizontal Scale: 6 inches = 1 mile.]
4‘ = positions of fossil zones,

\\ \ N Nx :
\ WKN \ | \ .
AN

a

Barricane, and in the cliffs at a small creek between Barricane and
Crunta Point. They include a Rhynchonella, so like Rh. Lewisii
of the Wenlock rocks that I have no doubt of its being the same
species; a small Spirifer with avery wide mesial fold and some-
what rough ribs, unlike any British species known to me; and
Orthis rustica, Modiolopsis, encrinites, etc.

1 Geol. Mag. 1878, p. 207.

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 261

At Morte Point, in addition to some large Lingule, the slates were
found to be covered with minute individuals of the same genus, but,
as their structure was completely obliterated, very little could be made
out of them. Inthe section (fig. 1) I have marked the positions of the
fossil zones, and the folds in the rocks which are to be seen between
‘Morthoe and Woolacombe. The same beds have doubtless been
several times repeated, but in some of the broken folds it is
probable that there are strata which belong to very different horizons.
Moreover, there is a somewhat marked difference in some of the
deposits. The flaggy beds which alone enable us to make out the
folds are succeeded by fine-grained dark slates, and as these are
found at a height of about 500 feet in the hill above Barricane, it
is clear that they alone must attain to a thickness of several
hundred feet.

III. Rockyuam Bay, Butt Pornt, Lez Bay, Lez, anp SLaveE.

Near the centre of Rockham Bay there is a well-marked fold in
which are some hard, gritty bands, and on the northern side dark
bluish-grey slates, which have yielded some small Lingule, but no
other distinguishable fossils. Between here and Bull Point there
are indications of another broken fold, and at Bull Point the dip
is N.N.W. in striped grey flaggy beds, which exhibit extensive
shiny cleaved surfaces. Similar rocks in well-marked folds are
found extending along the coast towards Lee Bay. In flags ob-
tained from a quarry on Flagstaff Hill, on the south-western side
of Lee Bay, I obtained some very large Lingule. On the eastern
side of the same bay are much crushed slates with fucoid-like
markings on the surface, and in the cliffs towards Shag Point are
greenish and yellowish flaggy beds, sometimes stained of a pinkish
colour. Small Lingule were fairly abundant in some of these beds.
Between Shag Point and Flat Point the beds are much broken, and
there are clear indications of an important fault. Beyond the
fault towards Ilfracombe the rocks are more massive in character,
and as they also contain many sandstone-bands, and have not
yielded any fossils, | have, for the present, thought it well not to
include them with the Morte Series. ‘They are also separated from
the typical Ilfracombe Beds by a fault, which extends along the
depression between Langley and the coast. ‘These beds are well
exposed in the Slade quarry, dipping S. at a high angle at its western
end, and folding round to the N. at its eastern end, where there
are beds of reddish and yellowish sandstones. These rocks call to
mind some of the Pickwell Down sandstones and shale-beds ; but it
must be admitted that at present their age, owing to the absence of
fossils, is indeterminable. In the Lee valley I found a few Lingule
and fragments of encrinites at several points in the Morte Series,
and in the quarry opposite the hotel small Lingulw are as abundant
as at Morte Point.

262 DR. H. HICKS ON THE MORTE SLATES, AND [May 1806,

IV. Muvxtacorr, SHeirin, anp [nFRACOMBE.

The discovery by me in 1891 of a fairly rich fauna in a quarry
on Mullacott Farm, having a strong Silurian facies, led me to make
a careful examination of the boundary-line between the Morte Series
and the Ilfracombe Beds in this area, and to note any special changes
visible in the beds near the junction. During this examination it
soon became apparent that there was no gradual passage between
the Ilfracombe Beds and the Morte Slates, as had previously been
maintained to be the case, but that there was everywhere an
important petrological difference to be noticed, which could only be
the result of beds of very different age being brought into contact
either by a fault or an unconformity. To enable me to make out
what was really the cause of this abrupt change, I found it necessary
to trace with care the Ilfracombe Beds to the north in coast-sections
and in the valleys about Ilfracombe, and evidence was soon obtained
to show that where beds had been indicated as dipping regularly to
the south, and hence under the Morte Slates, they as often dipped in
the opposite direction, that they were bent into a series of acute folds,
and that the strong cleavage had often been mistaken for bedding-
planes. After this it became possible to follow certain well-marked
beds through the various folds, and to make out that these rose up
higher and higher in the sections as we approached the Morte
States, and indicated the southern edge of a well-marked trough, as
shown in fig. 2. Further examination revealed the fact that there
was marked evidence of much crushing where the Ilfracombe Beds
were in contact with the Morte Slates, and therefore that the line
of separation here, at least, was an important thrust-fault.

Much of the evidence, so far as it relates to the Ilfracombe Beds,
has already been given by me in a paper in the Geol. Mag. for 1893,
therefore it is only necessary now to refer to that portion of the
evidence which more particularly explains the nature of the junction
between the Ilfracombe and Morte Beds. The Ilfracombe Beds are
often much broken by faults and frequently inverted, but there are
well-marked petrological and paleontological horizons which enable
the beds, even when most disturbed, to be identified; therefore,
though beds at different horizons are occasionally brought into
contact with the Morte Slates, the line of junction, when these facts
are borne in mind, can be, as a rule, easily traced.

In Mullacott Hill there is very little superficially to mark the
fault-line, but just above Score, in a quarry worked for road-
metal, some massive sandstone-beds of the Ilfracombe Series, though
in a greatly crushed condition, are seen dipping away from the
Morte Beds. North of Great Shelfin the fault runs along a narrow
valley, the hill on the northern side being formed by the basal sand-
stones of the Ilfracombe Series, and that on the southern side by the
Morte Beds. In an easterly direction the fault crosses the Oakridge,
and afterwards extends through the valley which runs nearly east
and west, north of Bowden.

The sandstones of the Ilfracombe Beds remind one much more

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET.

strongly of the Pickwell Down Sandstones
than of any found in the Morte Series,
and, like the former, they contain an
abundance of detrital mica. The slaty
beds in the Ilfracombe Series also are
often highly micaveous. It is neces-
sary to bear these facts in mind, for
though on the northern side of the
Ilfracombe trough, as at Combe Martin
and the Hangman Hills, the beds are
as little changed as they are on Pickwell
Down, yet on the southern side, near
the great fault, they are often so much
crushed and broken that the superficial
likeness is not at once evident. More-
over, the lowest beds are nowhere seen
in this area. On Mullacott Hill there
are several quarries which have yielded
fossils, but that which has yielded most
specimens is on the right side of the
road leading from Ilfracombe to Morthoe
Station, and less than 7 mile south of
the [Ilfracombe Cemetery. The beds of
purplish, greenish, and yellowish slates
dip at an angle of about 70° to E.S.E.
On the northern side of the quarry large
Lingule are fairly plentiful, but the
majority of the other fossils were found
in the beds on the southern side. They
comprise Stricklundinia lirata (some
specimens of very large size), Orthis
rustica, Ehynchonella Stricklandi, a
new Pterinea, Cardiola interrupta (?),
encrinites, fragments of a crustacean,
ete. The horizon indicated seems to
be the base of the Wenlock. In the
valley east of this quarry, which sepa-
rates the Mullacott from the Shelfin
ridge, there are several outcrops of the
slates, and these have also yielded
fossils, chiefly Lingule. In some
quarries in Shelfin Wood, on the north-
ern side of the Shelfin ridge, the slates
are covered with markings resembling
graptolites in a bad state of preservation.
The other fossils found along with these
are a few Lingule, one or two specimens
of Stricklandinia lirata, and tragments
of encrinites. In searching for fossils
in the Morte Slates it must always be

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264 - DR. H. HICKS ON THE MORTE SLATES, AND [May 1806,

remembered that the beds are much folded, and that fossils can only
be found in anything like a fairly well-preserved state in the limb
of the fold where the cleavage-lines and bedding-planes are nearly
parallel. In the arch of the fold the fossils are much crumpled, and
where the cleavage crosses the beds fragments only are found, though
a sharp blow directed in the line of the bedding, which is usually
much less marked than the cleavage-line, will sometimes reveal a
better specimen. Eastwards from this point the Morte Slates are
frequently exposed in small quarries and roadside sections, but there
are no quarries of any importance until we reach the neighbourhood
of Francis and Woolscott Barton. In the Francis quarry are some
thick beds of a yellowish shale, unlike the usual Morte Slates, and,
as they have not yielded any fossil evidence other than worm-tracks
and doubtful encrinites, there is nothing to guide one as to their
proper horizon.

V. Woorscotr Barron, SmirHson, AND Berry Down.

On Woolscott Barton Farm there are several old quarries in the
Morte Slates, but in none of these could I find more than traces of
fossils. In the slate-quarry in Smithson Wood, on the eastern side of
the valley which separates the Woolscott and Smithson farms, many
markings resembling graptolites were found on the surface of the
slates, also afew small Lingule, a small Orthis, and fragments of encri-
nites. The slates are of adark-bluish colour and well cleaved. Similar
slates are found in the road-cutting leading to Smithson Farm. In
the valley a short distance south of the adjoining farm of Hempster
I noticed some light-coloured felstone-dykes cutting through the
slates. At Berry Down the Morte Slates rise to a height of over
850 feet, but there are no quarries here of any importance. On the
road from Berry Down to Combe Martin the line of separation
between the Morte Slates and the Ilfracombe Beds occurs near
Henstridge, and the fault runs up the valley which extends for
some distance in a nearly east-and-west direction. Sandstones are
found in the southern side of Stoneditch Hill underlying the slaty and
calcareous beds of the Ilfracombe Series, which are much folded
here, as at Ilfracombe. Evidence that the Ilfracombe Beds lie in a
wide trough becomes perfectly clear in tracing the sections towards
Combe Martin, and identifiable fossils are to be found at several
points. The fossils here are, on the whole, in a better state of
preservation than near Ilfracombe, and the facts seem to point to a
diminishing intensity in the folding and shearing in an eastward,
direction.

VI. Summary or THE STRATIGRAPHICAL EVIDENCE
in Nortru Devon.

It may be well briefly to summarize the results given in this
paper, though any conclusions arrived at in regard to the general

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 265 :

succession of the rocks in North Devon will come in more appro-
priately after the second part of the paper, which will contain
the evidence obtained from other areas, has been read before the
Society.

The changed position now given to the Morte Slates removes one
of the greatest difficulties experienced by previous writers in their
attempts at correlating the strata in North Devon with those in
other areas, for nowhere else had such a thick series of well-cleaved
slates been met with at the horizons assigned to them here. The
horizons necessarily varied in accordance with the views in regard
to the succession held by the authors. Those who held with Prof.
Jukes that there was but one group in North Devon of sandstones,
slates or shales, and calcareous beds, repeated by faults, found it
necessary to place the Morte Slates at the top of the whole series ;
while those who claimed that there were two or more series of
somewhat similar sediments conformable to one another placed them
not far from the centre in the succession. There is good evidence
at many points to show that Prof. Jukes was correct in claiming
a faulted junction between the Morte Slates and the Pickwell Down
Beds, but the results produced by the faults are different from those
which he suggested ; for, instead of one great broken trough with the
Pickwell Down Beds coming up from under the Morte Slates, we
find the former resting upon the latter, the faults between being
due to crushing during the movements which brought the Morte
Slates and the Pickwell Down Beds to the surface.

‘Until the thrust-fault between the Morte Slates and the Lfra-
combe Beds on the northern side had been made out, the only way by
which a repetition of the beds could have taken place would be by a
great fault on the southern side; but this would necessitate a much
greater displacement of the beds than by that which is now
known to occur on the northern side of the Morte Slates.

The discovery of fossils in the Morte Slates belonging to several
horizons in the succession, and some probably as low in position as
the base of the Silurian (Upper Silurian of the Geological Survey),
added to the stratigraphical evidence, enables us now to speak with
confidence as to their place in the succession in North Devon. They
are the oldest rocks in the area, and they do not appear to contain
amongst them any beds newer than Lower Devonian. In some
places newer rocks may occur amongst them as the results of faults
or unconformities, but not in order of succession.

In the second part of the paper evidence will be given to show
that in at least one of the areas examined there appears to be a
passage from some of the Morte Slates to Lower Devonian rocks
containing so characteristic a fossil as Phacops (Crypheus) lacini-
atus. These passage-beds le on the southern side between fairly
typical Morte Slates and Pickwell Down Sandstones, and in the
latter, quite near one of the junctions, we discovered a band rich in
fossil wood, and other evidences indicating that they had been
deposited near land. When an interpretation of the succession in
North Devon and West Somerset, in accordance with the evidence

266 DR, H. HICKS ON THE MORTE SLATES, AND [May 1896,

recently obtained, is submitted, I think it will be seen that it agrees
far more closely with that which has been made out in other areas
in the British Isles than has hitherto been suspected.

VII. Description oF THE Fossits FounD In Norru Devon.
LinevLA MORTENSIS, sp. nov. (PI. X. figs. 1-5.)

This is probably the largest Lingula yet found in the British
Silurian rocks, and it occurs very plentifully in the Morte Slates,
though usually in a distorted condition. Elongated oval, the sides
nearly parallel. Rather acutely rounded in front, and tapering
gradually backwards towards the beak. Valves compressed, and
surface marked with numerous fine lines of growth, which here and
there are sculptured with cross markings.

Length 24, width 9 lines.

In size and shape it more closely resembles L. Brodiei, Davidson,
from the Woolhope Limestone, than any other species described
from the British Paleozoic rocks; but it is larger than that species,
and longer in proportion to the width. As one specimen only of
L. Brodie has been figured and described, it is possible, when others
have been discovered, that they may be found to agree more closely
with our shell, especially as they occur on the same geological
horizon. In association with the large forms there are others of
various sizes, and some of the surfaces are thickly covered with
minute specimens as in Pl. X. fig. 5.

Found at Woolacombe, Morte Point, Lee, Mullacott, and Shelfin.

SrRICKLANDINIA LiRATA, Sowerby. (Pl. X. figs. 6-8.)

This is the most characteristic fossil m the Mullacott quarry, but
though it occurs there in fair abundance it is most difficult, owing
to the crushing and cleavage, to obtain any good specimens. Those,
however, which have been found show that it attained a large
size, equalling nearly the largest forms foundin the Wenlock Beds of
the Island of Gothland.

According to Davidson, Stricklandinia lirata ‘ varies greatly im its
external shape...The size and regularity of the ribs are especially
variable in different specimens, as well as the length of the hinge-
line. (Monogr. Pal. Soc. ‘ Brit. Sil. Brachiop.’ vol. iii. pt. vil. p. 161.)

The suggestion first made tome by Mr. Sharman, of the Museum
of Practical Geology, that our fossil seemed more closely allied to
S. lirata than to any other brachiopod with which he was acquainted,
tempted me to make an examination of many of the specimens in our
museums ; and the fact, stated by Davidson, of its tendency to vary
greatly in shape and ornamentation I found very true. I cannot
say that, so far, I have been able to exactly match our fossil with any
other specimen, but undoubtedly it approaches most closely in its size
and ornamentation the specimens in the Society’s Museum and in the
Jermyn Street Museum, from the lowest beds of Wenlock age at
Marloes Bay, Pembrokeshire, and those from Gothland in the Natural
History Museum. The following characters, abstracted from those

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 267

given by Davidson in the full description in his memoir, published
by the Palzontographical Society, vol. ii. pt. vii. p. 159, can be
made out in our specimens :—‘ Transversely oval ; hinge-line nearly
straight and shorter

than the width of Fig. 3.—Jmpression of Stricklandinia lirata
the shell ... sides from Mullacott Quarry. (Natural size.)
and front rounded. — :

Valves moderately 7
convex. Dorsal valve
more or less semi-
circular and trilobed,
from the presence of
a rather wide mesial
fold of smallelevation
which, commencing
at the extremity of
the umbonal beak,
gradually widens as
it approaches the
front. Surface of
valves ornamented
with numerous angu-
lar, irregular, often
bifurcating ribs, and
concentric lines of
growth. Near the
umbo of the dorsal
valve are two elon-
gated pear-shaped
impressions, due to
the adductor or
occlusor muscles,
divided in the middle
by a central ridge.
Numerous pits (rough
tubercles on _ the
cast), probably ova-
rian markings, sur-
round these scars.’
The specimens are
so much compressed,
and also drawn out
of shape by the cleav-
age, that it was only
by the examination
of a large number [Reproduced from a photograph. ]

that all these points

could be clearly made out. There can, however, be no doubt
that the fossil is either S. lirata ora very closely-allied species. It
is an important fossil in defining the horizon, and the other fossils

ra

268 _ DR. H. HICKS ON THE MORTE SLATES, AND [May 1896,

found in the same quarry are such as would be expected to occur
with it in beds of Lower Wenlock age.

Found in the Mullacott and Shelfin quarries, near Ilfracombe.

RayNncHonELLA Lewisir(?), Davidson. (Pl. XI. figs. 1—4.)

Many specimens of this species have been found in the rocks on
the side of the path leading down to Barricane Beach, but, like
most of the fossils found in the Morte Slates, usually in a greatly
distorted condition. The specimens have also for the most part lost
the ornamentation characteristic of this species, but traces of it
are sometimes left in some of them. The pinched appearance of
the mesial fold is still retained, and the number of ribs in the
mesial fold and sides agrees exactly with those in the Shropshire
specimens from beds of Wenlock age. On p. 180, op. cit., Davidson
says that ‘ the range of this species is said to be in the Llandovery
and Wenlock rocks; I am, however, acquainted with the shell only
from the last-named formation, in which at some localities it is
exceedingly abundant.’ Hitherto the only locality in the Morte
Slates in which it has been found by us is at Barricane in Morte
Bay, in association with Spirifera Hamlingu, Lingula mortensis, ete.
Mr. Bather was kind enough to compare our specimens with those
in the Natural History Museum, and said that they agreed more.
closely with the typical specimens of th. Lewisia in the National
Collections than with any other species.

RHYNCHONELLA STRICKLANDI(?), Sowerby. (Pl. XI. fig. 11.)

A few imperfect specimens of this species have been found in the
Mullacott quarry. In size and shape the shell agrees with those
which occur in the Wenlock Limestone and Shale in other areas.
It has a very convex form, is from 12 to 15 lines in length, and the
surface is ornamented with from 25 to 30 narrow, simple, angular
ribs,

SprRIFERA Hamuinei, sp. nov. (Pl. XI. figs. 5 & 6.)

The specimens are compressed and distorted, but they show that
the shell was wider than long and moderately convex. The hinge-
line is nearly straight, rather longer than the width of the shell, and
somewhat pointed at the cardinal angles. Dorsal valve convex,
with a well-raised, wide, mesial fold. Surface of valves ornamented
with about 36 moderately strong rounded ribs, of which nearly a
third occur on the mesial fold. They are frequently crossed by fine
concentric lines, and here and there the larger ribs appear to be
ornamented with fine lines more or less parallel with them. Area
narrow.

Found at Barricane, in Morte Bay.

OrtuHts RUsTICA, Sowerby. (Pl. XI. figs. 7-10.)

This species occurs in fair abundance in the Mullacott quarry, anda
few specimens have also been obtained from the rocks on the northern
side of Barricane Beach. In each place they are much distorted,
but they show the characteristic ornamentation mentioned by
Davidson. He says at p. 239 (Monogr, Pal. Soc. ‘ Brit. Sil. Brach.’)

Vol. 52.] ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 269.

that ‘I must now again remind the student that one of the chief
characteristics of Orthis rustica consists in its generally having a
small interpolated rib between each two of the longer ones, or
between those which extend directly from the extremity of the beaks
to the margin, the number of ribs varying according to the age of
the individual.’ Among the specimens collected at Mullacott there
are examples of all sizes, and some quite as large as the largest found
in the Wenlock rocks of Shropshire. Its association here with
Stricklandinia lirata is highly interesting, and important in defining
the horizon of the beds; with the exception of S. lirata and Lingula
mortensis, it is about the most plentiful fossil in these beds.
Found at Mullacott and Barricane.

Moproropsts BARRICANENSIS, sp. nov. (PI. XI. figs. 14 & 15.)

This species approaches more nearly in shape Modhvolopsis sub-
alatus, Hall, of the Niagara Group, than any British species. It is,
however, a much larger form than the American species, and the
umbo is situated nearer the anterior extremity.

Length about 14 lines, greatest width about 7 lines. Sub-
rhomboidal in shape, posterior side greatly expanded. Anterior
extremity short and rounded. Umbo prominent. Surface marked
with moderately strong concentric lines, and near the anterior end
the concentric lines are crossed by numerous fine lines which extend
to the margin.

The shell is still convex near the umbo, but it has evidently been
much flattened by pressure.

Found in the cliffs on the northern side of Barricane, and Mulla-
cott quarry.

PreRIN#ZA MORTENSTS, sp. nov. (Pl. XI. figs. 16, 17.)

Several specimens have been found in the Maullacott quarry,
which exhibit characters sufficiently marked to indicate a new species
differing in several particulars from any other known British form.
The specimens are crushed and evidently somewhat distorted, but
show that the shell must have been broader than long, with a nearly
straight hinge-line. Anterior wing short and pointed, and separated
from the central part of the shell by a sulcus. Posterior wing long
and obtusely pointed. The surface of the shell is marked by
numerous radiating striz, which bifurcate as they approach the

-margin. Some specimens show traces of concentric lines of growth.
The umbo is prominent, and situated about a third of the distance
from the anterior extremity.

Width 16, length 10 lines.

Found, up to the present, only in the Mullacott quarry.

Avicona, sp. (Pl. XI. fig. 18.)

No perfect specimens have been found, but the fragment figured
shows that it is distinct from any British species. It, however,
somewhat closely resembles one of the species (Avicula undata)
from the Niagara rocks of America.

Found in the cliffs, northern side of Barricane.

270 DR. H. HICKS ON THE MORTE SLATES, AND [May 1896,

EXPLANATION OF PLATES X. & XI.

Puate X,

Figs. 1-4. Lingula mortensis, sp. nov. 34. Enlarged portion of shell, showing
ornamentation. Fig. 5. Probably young specimens of the same
species. Mullacott, Shelfin, and Morte Point. Author’s Collection.

Figs. 6-8. Stricklandinia lirata, Sowerby. Mullacott Quarry. 6, Collection of
the Rev. G. F. Whidborne ; 7 and 8, Author’s Collection.

Figs. 9,10. Crania, sp. Mullacott Quarry. Author’s Collection.

Puats XI.

Figs. 1-4. Rhynchonella Lewisii(?), Davidson. Barricane, in Morte Bay.
Author’s Collection.

Fig. 11. Rhynchonella Stricklandi (?), Sowerby. Mullacott Quarry. Author’s
Collection.

Figs. 5 & 6. Spirifera Hamlingii, sp.nov. Barricane, in Morte Bay. Author's
Collection.

Figs. 7-10. Orthis rustica, Sowerby. Mullacott Quarry. Author’s Collection.

Figs. 12 & 18. Stricklandinia, sp. Mullacott Quarry. Author's Collection.

Figs. 14&15. Modiolopsis barricanensis, sp.nov. Barricane, in Morte Bay, and
Mullacott Quarry. Author’s Collection.

Figs. 16 & 17. Fterinea mortensis, sp. nov. Mullacott Quarry. Author's
Collection.

Vig. 18. Avicula, sp. Barricane. Author’s Collection.

Fig. 19. Cardiola interrupta (?), Sowerby. A fragment, much enlarged. Mulla-
eott Quarry. Author’s Collection.

Fig. 20. A fragment of a Crustacean (carapace ?), Author’s Collection.

Discussion.

The PrestpEnt said that six years had elapsed since the Author
attacked the problem of the rocks of North Devon and their
succession. On the former occasion he obtained a verdict of
‘not proven.’ After further careful work on these beds, the
Author now came forward with additional evidence from the field
and from the fossils derived from the rocks to prove that his
reading of the succession of the Devonian rocks is the true one.
He (the President) invited discussion (1) en the stratigraphical,
and (2) on the paleontological evidence.

Prof. Hueuss believed that the thickness of the several divisions
of the Devonian had been greatly exaggerated, and that the vertical
distance of the beds, now proved by Dr. Hicks to be fossiliferous,
from the known fossil-bearing beds of Hele, for instance, was not
really great. He thought that, although the lithological difference »
between the main mass of the Morte Beds and of those which
occurred on either side of it was very great, there were alternations
of the sandy and slaty type in the contiguous strata. In so
disturbed an area faults would be apt to occur where rocks of
unequal resisting-power were crushed together, and this, with
the overfold of the anticlinal arches, might give a deceptive
appearance of an unconformable junction. The proof of the theory
proposed by the Author depended chiefly upon the palzontological
evidence. Taking the more important test-fossils laid upon the
table, namely, Cardiola interrupta, Stricklanduua lirata, and the

Vol. 52.] | ASSOCIATED BEDS, IN N. DEVON AND W. SOMERSET. 271

eraptolites, he thought that the first was an imbricated shell, like an
Atrypa, perhaps A. aspera, but that it certainly did not show the
cross-ribbed surface from which C. interrupta took its name. The
second was founded on distorted specimens of Spirifera disjuncta ;
and the so-called graptolites were lines of an asbestiform mineral
following broken vein-like cavities, which had perhaps in some
cases been occupied by encrinite-arms and stems, the joints of which,
together with regular step-like displacements during the movements
that modified the structure of the rock, produced the scalariform
appearance of graptolites.

The Author had added greatly to our knowledge of the Devonian
rocks by his discovery of fossils in the Morte Series, but the speaker
thonght that the rocks and fossils suggested a comparison with the
Tintagel Beds rather than with the Silurian.

The Rev. G. F. Warpporne had had the privilege of following
the Author’s work in the field and collecting fossils with him, and he
was convinced that the Author had not only found an abundant fauna
in the ‘ unfossiliferous ’ Morte Slates, but had discovered the true
bedding-planes, and thereby proved the thickness of the deposits in
North Devon to be much less than had been supposed. He had very
carefully examined the fossils on the table, and was convinced that
they did not present a Devonian facies. He had been unable to
reconcile them with any Devonian fauna that he knew. Nor could
he agree with Prof. Hughes that the large specimen of Stricklandinia
lirata could by any possibility be a distorted Spirifer Verneuili.
It differs from that form both in shape and minute ornament.
The fragment of ‘Cardiola interrupta?’ also seemed to be more
like that fossil than anything else, though it was difficult
to determine in its fragmentary condition. It certainly was not
Atrypa aspera.

Mr. Marz said that the dip of the Ilfracombe Beds from the Morte
Slates below the supposed thrust-plane was not evidence of the
existence of a thrust-plane. But the serious evidence was that of
the fossils. He maintained that none of the fossils exhibited were
definitely proved to be Silurian. He could not see any indications
of graptolitic structure in the specimens on the table. The greatest
stress had been laid on the supposed Stricklandinia lirata. He
wished that the gentleman who had identified that specimen had been
present to say definitely that it was Stricklandinia. Considering
the number of forms closely related to Silurian forms which had
been found in American Devonian rocks (for example, Pentamerus
pseudogaleatus), and the fact that in the richly fossiliferous deposits
of Bohemia, Barrande’s stages F,G, H, now shown by Kayser to be
Devonian, were originally described as Silurian, he did not think
that the distorted fossils displayed on the table could be taken as
evidence for upsetting the received classification of the North
Devon rocks. The Author was to be congratulated on the discovery
of fossils in these supposed barren rocks, but the speaker, though
having no objection to the reference of the Morte Slates to the
Silurian, hoped that more evidence would be forthcoming in the

272 THE MORTE SLATES AND ASSOCIATED BEDS. [May 1396,

second part of the paper before ay were definitely accepted as
such.

Mr. H. B. Woopwarp ronianied that the Devonian system had
always suffered from being founded on zoological characters without
clearly defined stratigraphical evidence. The Author’s paper should
be studied in conjunction with the excellent work of Dr. Hinde and
Mr. Howard Fox on the radiolarian rocks, which were probably
of the age of our Yoredale Beds. ‘The precise equivalents of
the lowermost Carboniferous in Devon were not established, and
there had been no base to the Devonian system. For the sequence
of Devonian faunas we had to take the divisions made in Germany ;
and as it was not clear that the base of the Carboniferous there was
the same as that in this country, it might be questioned whether
the continued use of the term ‘ Devonian’ was justified. Agreeing
that the subdivisions in Devon must be worked out by their
fossils, he hoped that in so complicated a region the species would
be identified solely from their zoological characters, while the best
basis for such detailed work was an independent 6-inch survey of
the area.

Mr. Horxrnson said that he had examined numerous specimens
collected by the Author which bear a general resemblance to grapto-
lites, and of which he exhibited drawings made under the micro-
scope. Some of these might not be organic, others might be worm-
tracks or encrinite-stems, or impressions of other oryanisms, but he
felt. certain that there were graptolites among them; they were,
however, in so bad a state of preservation that it was impossible
to identify them. He believed that most of the graptolites belonged
to the genus Monograptus, and therefore were of Silurian age, but
that Ordovician genera also occurred, showing that the rocks from
which they had been obtained were of different horizons. Some of
the branching forms were probably Cladophora, belonging to the
genus Dendrograptus. He could not believe it possible that —
mineral matter could simulate, as suggested by Prof. Hughes, such
forms as he then drew on the blackboard, one being typical of the
Monograptus Sedgwickii group (having long curved denticles), and
another resembling a scalariform impression of a Climacograptus
(with transverse oval cell-apertures). He hoped that specimens
would be obtained in a sufficiently perfect state of preservation to
enable them to be specifically identified, dispelling all doubt as to
their nature.

The Avruor said that he would reserve his reply until the second
part of the paper is read, when evidence will be presented which
will clear up many points referred to in the discussion. There can be
no doubt that the Morte Slates, in their lithological characters and
in their fossil contents, are entirely unlike the surrounding Devonian
rocks.

Quart .Journ.Geol.Soc.Vol.Lil egy a

Mintern Bros.imp.

ath.

F.HMicheel del.et1

PALZOZOIC MOLLUSCA OF

WORTH DEVON.

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Oiewt.Journ.Geo!.sor Vol LI Pi: AL

FH.Michaeldel.et hth. Mintern Bros irnp.
PALZ0 ZOIC MOLLUSCA OF
NORTH DEVON.

Vol.52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY, 273

14. On the Lianpovery and Assoctatep Rocks of Conway (Norra
Wates). By Miss G. L. Erres and Miss E. M. R. Woon,
Bathurst Students, Newnham College, Cambridge. (Com-
municated by J. E. Marr, Esq., M.A., F.R.S., Sec. G.S.
Read January 8th, 1896.)

ConTENTs.
Page
Beebucroguehion, and Description Of Av0a i ..2.cc0cssco.cncsscseecsosees 273
MUR oe PUES o2 co ks nnn connote preset tacteeentinas cmansich Ledéasnceherseecse LTO
mirc cricral SAQUPMCO 2.500 --h-capre sega cate eenna oinlnae raat schecsc dente cesses 276
ie Wetaled Wexeriptiomor WHE COS ioc. scnssncscevenssteseccs sete ssccuae- 277

1. The Llandovery Rocks.

2. The Tarannon Shales.

3. The Wenlock Shales.

4. The Denbighshire Grits and Flags.

Mer yerclation with Oller AYERS. : Lacés.ccteek onc ccshacedeoaeescecdivdeses en's 284
1. The Llandovery Rocks.
2. The Taranuon Shales.
3. The Wenlock Shales.
4, The Denbighshire Grits and Flags.

als Cilla OnClUSIONS ensncecheebceteesurih soon eacceeee Spies hetateeavedass 288
Geological Map of District south of Conway ...................0.005 274.

I. Inrropuction, AND DEscriprion oF AREA.

Tuer Geological Survey Map (Sheet 78 N.E.) of the district lying
immediately south of the town of Conway reveals an outcrop of
Tarannon Shales, which is curious as regards its relation to the
associated formations, since the Tarannon Shales are represented as
being both underlain and overlain by rocks of Wenlock age. This
circumstance led us to examine this special area; and our attention
haying already been directed to the occurrence of graptolitic shales
below the Tarannons in other parts of Wales, we thought it possible
that they might also be present in the Conway district.

Our observations in that district have extended over a fairly wide
region, including the greater part of the valley of the Afon Gyffin
between Conway and Y-Ro; but the only area which we have
mapped in anything like detail lies immediately south of the town
of Conway itself, and occupies the hill opposite Conway Castle
and the railway. This area is bounded on the east by the River
Conway, and on the west by a fault (‘ boundary-fault,’ as we term
itin the following pages) which brings a calcareous grit of Bala age
against Silurian beds.

The northern limit of the area is formed by the Afon Gyffin, a
tributary stream of the River Conway, which it joins just below the
Castle. The southern limit has been taken, for convenience, at the
beginning of the dense woods belonging to Benarth Asylum. In
other places higher up the valley, where we hoped to find a similar
succession, the ground was low-lying and all rock-exposures were
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Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 275

The geological structure of the area is fairly simple, though the
beds are faulted and give indications of having been disturbed, the
cleavage in many cases being in a direction at right angles to that
of the plane of bedding. ‘There is no great variation in the litho-
logical characters of the beds; they are all of the general type
known as ‘greywacke,’ and graduate locally from thick-bedded
gritstones, through smooth flagstones, and thin-bedded hard grey
shales down to fine-grained graptolitic mudstones. The only fossils
with which we have to deal are graptolites, and their value for
purposes of stratigraphical correlation is now too well known to
need comment.

II. LitvERATURE.

The succession of rocks at Conway has received but little attention
at the hands of geologists, and the literature is in consequence
somewhat scanty. In the second edition of the Geological Survey
Memoir on North Wales (1881) the succession at Conway is given
as follows :—

Wenlock Shale.
Denbighshire Grit. } Wenlock gis

Tarannon Shale.
(Upper and Lower Llandovery Beds absent.)
Caradoc or Bala Beds.

It is also suggested that the absence of Llandovery rocks between
Conway and the country east of Bala Lake may possibly be due to the
overlap of the Tarannon Shales, which are said to rest on Lower
Silurian rocks at about the horizon of the Bala Limestone.

The Tarannon Shales form a narrow band at the base of the
Denbighshire Grits extending from Conway to Llanbedr, about 5
miles to the south, being interrupted only by three small faults
with a downthrow to the east.

On the hill immediately south of Conway the base of the grits,
resting on a narrow band of Tarannon Shales, strikes towards
Gyffin and, dipping east at an angle between 10° and 30°, passes
south by Y-Ro to Caerhun, where the western boundary is lost
in the alluvium of the River Conway. It is also stated that the
grits pass up into the Wenlock Shale, but no mention is made of
the considerable thickness of Wenlock Shale which we have found
below the lowest grit-band in this district.

Prof. Lapworth, in his classical work on the ‘ Distribution of the
Rhabdophora’ (Ann. & Mag. Nat. Hist. ser. 5, vols. v. & vi. 1880,
pp. 45, etc.), records the occurrence of many graptolites in the
Tarannon Shales of Conway. On paleontological grounds he con-
cludes that the Tarannon Shales of Conway correspond to the lowest
portion of the Gala Group of Southern Scotland, that is, with the zone
of Monograptus exiquus.

Our work necessitates a modification of the views of the earlier
Surveyors, though we are in complete agreement with Prof. Lap-
worth’s suggestion as to the horizon of the Tarannon Shales of this
district.

Q.J.G.8. No. 206, U

276 MIS8 G. L, ELLES AND MISS E. M. R. WooD oN THE [May 1896,

III. Generat Sequence.

In this area we believe that we have a succession of graptolitic
mudstones representing beds of Llandovery, Tarannon, and Wenlock
ages, and we hope to show that the omission of Llandovery Beds in
the Conway succession of the earlier surveyors was erroneous. We
consider that the general sequence in descending order is as
follows :—

5. Denbighshire Grits and Flags.
4. Wenlcck Shales.

3. Tarannon Shales.

2. Upper Llandovery Beds.

1. Bala Beds.

The junction between the Bala and Llandovery rocks is nowhere
visible. The former do not come to the surface south of the
Afon Gyffin, but at the time of our first visit drainage-operations
were in progress along the road passing the timber-yard on the way
to Benarth, and at a few feet below the level of the road black
graptolitic shales containing Diplograptus foliaceus (Murch.) and
Climacograptus bicornis (Hall) were seen, apparently in situ, under-
lying the Tarannon Shales. If this be really the case, the Lower
Tarannon rests unconformably on rocks of Bala Limestone age, and
the succession is here different from that seen on the other side of
the fault (F. 2 in map, p. 274), where Llandovery rocks occur, but
if is unlikely that the Birkhill Shales have been overlapped in this
short distance.

Since there is no junction visible between the Bala and Llan-
dovery rocks, we are unable to determine definitely whether the
Lower Llandovery rocks are absent or not in the district,

Note on the Bala Rocks of the Conway District—On the other side
of the River Conway, in a quarry of Bala rocks on the hill above
Deganway, we have found remains of several large trilobites. Many
seem referable to the species Phacops appendiculatus (Salt.) (=P. eu-
centra, Ang.?). This would tend to show that we have here repre-
sentatives of the Ashgill Shale fauna of the Lake District. If this
be the case, there exists in this part of North Wales a higher series
of Ordovician rocks than has hitherto been supposed, and hence the
break between Ordovician and Silurian rocks is less than was formerly
believed to be the case. tae

The Upper Llandovery rocks pass up conformably into the
Tarannons; but on paleontological grounds we believe that the
latter are overlapped by the Wenlock Shales, and that the highest beds
—-that is, the zone of Cyrtograptus Gray (Lapw.)—are not present
here.

The best section of the Wenlock Shales is to be seen on the shore
helow Benarth, and here we approximately determined the upper
limit of these beds, on lithological grounds, at a point where the
beds become more flaggy in character and contain bands of grit.

The exposures on the side of the hill were not sufficiently good to
enable us to determine the upward limit with certainty.

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 277

There are two main faults in this district: one (F.1), as has
been mentioned above, forms our boundary-line to the W. and strikes
10° W. of N.; while a second one (F. 2), striking 30° S. of W. and

Fig. 1,
Ss. N.

SEcTION THROUGH A.B

Fig, 2.
N.N.W. SSE.

Aron Grrrin Roao To.Gyerin Fauct (f2) Louse. Roao. River
———— = ————— Wail 1 Conway

2)
Section THRousH G.D.

with a downthrow to the E., brings the Upper Llandovery and
Tarannon beds against the Wenlock Shales. We believe that the
occurrence of Upper Llandovery Beds is dependent in a great
measure on this second fault.

IV. Derartzep Description or THE Beps.
1. The Llandovery Rocks.

Rocks which are undoubtedly of Llandovery age occur on the
right bank of the Afon Gyffin, from opposite Neckarmount House to
the timber-yard buildings. Farther W. they are concealed beneath
the alluvium of the river. They strike 10° N. of W., and dip 10° W.
of S. at an angle of about 55°. Continuing on this strike, they are
again seen in vertical section in the high bank opposite the fork
formed by the junction of the Benarth and Gyffin roads; here they
occur slightly below the level of the road, and probably occupy the
whole of the marshy ground lying between the road and the bank.

_(a) Stream-section.—The beds seen in section near the stream are
capable of the following subdivisions, in descending order :—

. Hard grey bed.

. Black shale-band, with Rastrites maximus.
Grey flagstones.

. Black shale-band, with graptolites.

Grey flagstones.

. Black shale-band, with graptolites.

. Very tough flagstones.

MDD CO OD 7

1. Tough Grey Flagstones.—Little need be said of the un-
fossiliferous beds forming the base of the section. They consist of
tough grey flagstones, and are well exhibited in the bed of the

v2

278 MISS G, L, ELLES AND MISS E, M. R. WOOD ON THE [May 1896,

stream, They call to mind strongly the so-called Barren Mud-
stones of Moffat (Lapworth, Quart. Journ. Geol. Soc. vol. xxxiv.
1878, p. 240) and other areas. They are about 4 feet thick, but
their base is not visible.

2. Black Shale-band.—This band is composed of typical black mud-
Stones ; it is only a few inches thick, and is much weathered, so
that large blocks are not obtainable. We identified the following
graptolites : —

Rastrites peregrinus (Barr.). Monograptus gregarius, Lapw. C.

Monograptus Hisingeri, var. nudus Diplograptus tamariscus (Nich.).
(Lapw.). C.

HMisingeri, var. gaculum (Lapw.). Climacograptus normalis (Lapw.).

(C=very common. c=common, R=rare.)

3. Grey Flags.—The black fossiliferous band No. 2 is separated
from the band No. 4 by a foot of grey flagstones, very similar in
character to those found at the base of the section.

4. Black Shale-band.—Very similar to band No. 2, but fossils are
rather more abundant. This band is also of inconsiderable thick-
ness. We have found in it the following fossils :—

Monograptus concinnus (Lapw.). Diplograptus sinuatus (Nich.). C.
—- fMisingeri, var. nudus, Lapw. — Hughesii (Nich.).

, var. gaculum (Lapw.). tamariscus (Nich.). C.
gregarius? (Lapw.). Climacograptus normalis (Lapw.).
— lobiferus (M‘Coy). C.

eee

5. Grey Flagstones.—These differ in no particular from those
already described.

6. Black Shale-band.—This, the uppermost black shale-band that
occurs in the section, is by far the most important. It is exposed
about 3 yards from the top of the bank, below the uppermost bed
of grey flagstones. The bed weathers very deeply, and has a curious
rough fracture which renders it easily recognizable. The band is
richly fossiliferous, and has yielded the following graptolites :—

Rastrites maximus (Carr.). C. Monograptus lobiferus (M‘Coy).
gemmatus (Barr.). — spinigerus (Nich.).
distans (Lapw.). turriculatus (Barr.). R.
Monograptus argutus (Lapw.). Petalograptus ovatus (Barr.).
Barrandii (?) (Suess). palmeus (Barr.).
concinnus (Lapw.). Diplograptus sinuatus (Nich.). O.

gregarius (Lapw.). R. tamariscus (Nich.). C.
galaensis (Lapw.). R. Hughesii (Nich.). ©.

—— fisingeri, var.nudus (Lapw.). Climacograptus normalis (Lapw.).
, var. gaculum (Lapw.). c¢. c.

——

(b) Marsh-section.—The beds seen in section in the bank of
the marsh are, as before mentioned, a continuation of those seen by
the stream, and here, as before, they dip steadily in towards the hill,
The marsh, which occupies the space between the road and the
bank, lies about 3 feet below the level of the road, but the ground
rises somewhat towards the bank. Were it not for this depression,
no Llandovery Beds would be seen here, as the band with Rastrites

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 279

maximus is found almost at the level of the road, and the black
band No. 4 is only just visible at the foot of the bank. This band
disappears almost at once when traced east or west, and the zone of
Rastrites maximus is also lost at the level of the road on either side
of the depression.

The section is, however, very interesting as affording an oppor-
tunity of studying the passage from the Llandovery rocks into the
Tarannon Shales. There occurs in this place a graptolitic band
above the zone of Rastrites maximus. This must be, from its
position, either a passage-zone or the lowest bed of the Tarannon
Shales. From the character of the fauna presently to be described,
we prefer to regard it as a true passage-bed.

The following is the section seen at this locality, the nas
being enumerated in descending order :—

9. Spotted grey flagstones to summit. Ft. In.
8. Black graptolitic band (probably passage-zone) ......... 0 6
7. Grey flagstones, with hard gritty band about 1 inch

BV DRE a 5c 1 cestaton et dc cgnaha cadres wet os daencie 11.8
6. Shale band; zone of Rastrites MAXIMUS .......ceceeveeees PO
5. Grey flagstones, unfossiliferous..........sssecsscseececeeeees 70
4, Black shale-band, just visible.

(The beds are numbered to correspond with those of the stream-section.)

From the nature of the exposure of No. 4, we scarcely expected
to find any fossils. We succeeded, however, in obtaining a few
graptolites, but these were too fragmentary for specific deter-
mination.

Zone of R. maximus, Band No. 6.—This band is easily recognizable
by its characteristic fracture and mode of weathering. It has
yielded the following graptolites :—

Rastrites maximus (Carr.). C. Monograptus gregarius (Lapw.).
Monograptus concinnus (Lapw.). R.

spinigerus (Nich.) ?

— Hisingeri, var. nudus, Lapw.

erassus (Lapw.).
involutus (Lapw.) ?

C. turriculatus (Barr.). R.
— —, var. jaculum (Lapw.). Petalograptus ovatus (Barr.).
C. palmeus (Barr.).
cyphus (Lapw._). Diplograptus tamariscus (Nich.). C

— galaensis (Lapw.). R. Hughesii (Nich.). OC.

It will be observed that in this locality and in the stream-section
the zone of Rastrites maximus is characterized by the abundance of
Diplograptus belonging to the species Hughesi (Nich.), tamariscus
(Nich.), ovatus (Barr.), and palmeus (Barr.). The first two are by
far the most numerous.

The upper limit of the Llandovery Beds appears to be well defined
by the hard gritty band occurring at the base of No. 7.

8. Fossiliferous Band.—This differs somewhat in lithological
characters from the lower graptolitic bands. It is not so black, nor
is it so soft, being of a more gritty nature. It yielded the following
fossils :—

280 MISS G.I ELLES AND MISS E, M. R. WOOD ON THE [May 1896,

Monograptus Hisingeri (Carr.). * Monograptus pandus (Lapw.).
. erispus (Lapw.). lobiferus (M‘Coy).
= ef. sartorius (Tullb.). ef. nodifer (‘Tullb.).
= cf. speciosus (Tullb.), i ice Hug hesii (Nich.).
a runcinatus (Lapw.). Climacograptus normals (Lapw.).

It is this fauna which leads us to believe that the zone is a
passage-zone, as the fossils marked with an asterisk are characteristic
Tarannon forms, while the other species are common in the Llan-
dovery Beds.

2. The Tarannon Shales.

(a) Marsh-section.— Unfortunately the lowest beds of the
Tarannon Shales in this district are not very fossiliferous—at least
in places which are accessible, for much of the section is obscured
by buildings and lumber from the adjoining timber-yard.

At the corner of the road, however, we succeeded in obtaining
two slabs on which were seen a number of badly preserved Mono-
graptids. Many of these were too obscure for identification, but we
have determined M. pandus (Lapw.), M. Hisingeri, var. nudus
(Lapw.), Cyrtograptus Lapworthi (Tullb.), and C. (?)speralis (Gein.).

These beds were almost immediately faulted out against the
Wenlock Shales.

(b) Section opposite the Forge.—The section of Tarannon Shales
seen opposite the forge is by far the best in the district, and con-
tains a rich graptolitic fauna. It was from these beds that Prof.
Lapworth obtained the fossils recorded by him in his $ Distri-
bution of the Rhabdophora’ (Ann. & Mag. Nat. Hist. 1880, ser. 5,
vols. v. & vi.). The strike of the beds does not appear to have
been affected by the fault, and they dip 10° W. of 8S. at a fairly
constant angle of about 55°.

The beds consist of alternations of hard grey unfossiliferous flag-
stones, with softer black shale-bands containing graptolites. They
are quite different in character from the Llandovery rocks, and are
not so fissile.

The following is the complete section seen ; the lowest beds occur
exactly at the corner by the forge, while higher beds come on along
the road in either direction :— wee

Ms SROOiP and LOOSE SHALC i... ves o+cepemsesie se snienthen seen eehlstee ooein geeee 4 0.

2. Bands of hard grey flags, with softer seams. Unfossiliferous... 2
11. Black shale-band, with graptolites. Very ferruginous and

deeply SYBOUNOLEA 5: didancsiss hen oe ee 6
MORGUE N SMA CRLONGR)<.6ceansee Wien sinsetiels ancadownegienecusee veeace pence eee 0 9
9. Black shale-band, with graptolites. Very soft, and stained

CMON HOA ecco Zoo 0 etadceambue ic deans hunch gidemamenst sk cae st eon 0
8. Grey flagstones .. i bres ales eleraieelslats Saja ays sds eijcim eterna ane Er 0 9
Weesolt plackigraptolitie: shale, ch sp.cave-lyasiai/bosecbeuilensaenevageeenen 0 6
6. Grey flags, with narrow band of hard yellow grit: all very

POVTU OTM OUB ssn ais weisoe <hacr asec eideew oaisp Sevice cues eoaa nen geee ee ee eeeene 5
be Nott black shale, with graptolites’ .2.2...:.,0ss.cko.neseeeedenbeuewens 0 9
A-aUintossiliferous prey Mae Ol. .fecdecc.tenbasientontsaseetbilens sepeebbone Ont
vocblack shale, with, praptolites 05 .0-js+<s0ss0cdsss0 sas ebavcanecanspen@en 0 92
ROME VRHAGB 0. sce cconcas doeetns teed oes Saatasdnee soaecedasa nieeaceeeeene 1 0
1. Grey, sandy, graptolitic band ; iron-stained above. .

(Base not seen.)

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 281

Band No. 1.—Lithologically this band differs from any of the
other graptolite-bearing bands seen in this section. It may be
roughly separated into two divisions :—

(a) Lower. Sandy grey bed.
(6) Upper. Flaggy bed, stained bright red.

In the lower of these two divisions the graptolites are very
numerous but fragmentary, and for the most part very badly pre-
served ; those in the upper division are more easily determinable.
We obtained the following fossils :—

Monograptus pandus (Lapw.). C. Monograptus speciosus (Tullb.).
runcinatus, var. (Lapw.). crispus (Lapw.).

— exiguus (Nich.). O. turriculatus (Barr.).
nodifer (Tullb.). Becki (Barr.)?

— Hisingeri, var. nudus (Lapw. ). ? urccolus (Richter).

, var. gaculum (Lapw.). Petalograptus palmeus (Barr ).
broughtonensis (Nich.). Diployraptus tamariscus (Nich.).

———

The unfossiliferous flagstones are very similar throughout ; they
consist of pale grey flaggy beds, occasionally somewhat gritty, and
are otten Hees hard. Some of the upper beds are speckled.

Band No. 3.— This soft mudstone-band has yielded the following
forms :—

Monograptus pandus (Lapw.). Monograptus? urceolus (Richter).
runcinatus, var. (Lapw.), cf. flexuosus (Tullb.).
exiguus(Nich.). C. capillaceus (‘Tullb.).

turriculatus (Barr.). C. Petaloyraptus palmeus (Barr.),
ef. cygneus (‘Tornq.).

Band No. 5.—From this band we have identified

Monograptus turriculatus (Barr.). Monograptus galaensis (Lapw.).
pandus {Lapw.). Flemingvi (Salter).
runcinatus, var. (Lapw.). — ? urceolus (Richter).

— Hisingeri, var. nudus (Lapw.). Proteus (Barr.).

—— exiguus (Nich.). Petalograptus palmeus (Barr.).
crispus ? (Lapw.). ovatus (Barr.).

Band No. 7.—This contains

Monograptus turriculatus (Barr.), C.. Monograptus speciosus (Tullb.).
exiguus (Nich.), retroflerus ? (Tullb.).

—- Hisingeri, var. nudus (Lapw.). Diplograptus tamariscus (Nich.).
pandus (Lapw.).

Band No. 9.—This bed is peculiar, because of its being stained
bright yellow; it has yielded

Monograptus pandus (Lapw.). Monograptus Hisingeri, var. gaculum
turriculatus (Barr.). (Lapw.).
crispus (Lapw.). aa ovatus (Barr.?). C.
—- exiguus (Nich.). palmeus (Barr.). C.
priodon (Bronn), fretiolites Geinttzianus (Barr.).

— Hisingeri, var. nudus? (Lapw.).

Band No. 11. This band consists of black flaggy mudstones, deeply
weathered and often iron-stained. It breaks characteristically into

282 = MISS G. L, ELLES AND MISS FE. M. R. WOOD ON THE [May 1896,

lath-shaped fragments with a splintery fracture. We have obtained
from it the following :— 7

Monograptus pandus (Lapw.). C. Monograptus speciosus (Tullb.).
runcinatus, var. (Lapw.). C. —- ef. cygneus (Torngq.).
exiguus (Nich.). C. —— priodon (Bronn).
attenuatus (Hopk.). —— concinnus (?), Lapw.
crispus (Lapw. ). ? wrceolus (Richter).

—— broughtonensis (Nich.). Petalograptus ovatus (Barr.).

—— turriculatus (Barr.). C. palmeus (Barr.). C.
riccartonensis (Lapw.). Diplograptus tamariscus (Nich.).
, 8p. Nov. ——- Hughesii (Nich.).

—— Hisingeri, var. nudus (Lapw.). Retiolites Geinitzianus (Barr.).

— , var. jaculum (Lapw.). — obesus (Lapw.).

galaensis (Lapw.).

Strictly speaking, this band might be divided as follows :—

(a) Graptolitic Shale.
(0) Unfossiliferous Flags.
(ce) Graptolitic Shale.

But (6) is of such insignificant thickness that for practical purposes
it seems better to group the three as one bed.

Tt will be evident from these lists that several species of grapto-
lites are common to all the bands: for example, Monograptus
exiguus (Nieh.) and M. turriculatus (Barr.) range throughout, and
have been found on the same slab; M. pandus, Lapw., and M. runei-
natus var., Lapw., are also commonly associated with these. .

(c) Shore-sectton.— The only other place where we found a
workable section was that seen at low tide on the shore between the
timber-yard and the lodge belonging to the Benarth Lunatic Asylum.
The section commenced just at the old landing-stage.

The dip and strike remain constant as before, but, owing to the
tact that beds are denuded along their dip, they are exposed somewhat
farther to the south than is the case in the road. Unfortunately,
where we hoped to find the highest beds the section was obscured
by sand and shingle, and the rocks next visible were certainly
of Wenlock age, since they contained Monograptus priodon (Bronn),
M. vomerinus (Nich.), ete.

We believe that there is a continuous outcrop of Tarannon Shales
from the fault (F. 2) to F. 1, the boundary-fault; but there are no
good exposures, as the ground is chiefly a grassy slope. The presence
of these beds was therefore in most cases inferred by the disappear-
ance of the feature invariably formed by the Wenlock Shales.

3. The Wenlock Shales.

A considerable thickness of Wenlock Shale underlies the lowest
band of Denbighshire Grit in this district. The outcrop assumes a
curious form to the west, owing to the presence of the fault (F. 1)
and to the configuration of the ground.

Lithologically, the beds differ markedly from the underlying

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 283

Tarannon Shales; they are generally harder, of a lighter, often
speckled colour, and in places very shivery. The fossils are fairly
well preserved, but, owing to the direction of the cleavage, are often
difficult to obtain. The beds change their strike somewhat as they
approach the faults, being in each case bent up towards them ; this
is especially well marked in the case of the fault which forms the
boundary of the Silurian rocks to the west. We were fortunate in
having several workable exposures on the hillside, and these we will
proceed to describe in some detail.

(i.) Sections West of Fault (F. 2).

(a) Section S.W. of Rose Mill Farm.—The sections exposed near
Rose Mill Farm are of small extent. They are chiefly interesting
as showing the alteration in the strike of the beds as these approach
the fault. Here the strike is 20° N. of W., while as a general rule
it is 10° N.of W. The fossils here are for the most part but poorly
preserved, but we have identified Monograptus personatus, Tullb.,
M. vomerinus, Nich., M. broughtonensis (Nich.), and Cyrtograptus
Murchisoni, Carr. At Rose Mill Farm itself the shales are very
shivery, and from the nature of the rock no fossils were obtainable.
Here and south of the farm the strike is 15° N. of W.

(3) Neckarmount.—An exceedingly good section is exposed along
the rough cart-track which leads up from the road, past Neckarmount
House, to the farm.

The beds appear to come on about 160 yards above Gyffin Road ;
they dip steadily into the hill to the S.S.W. at a high angle of
about 50°, and maintain a constant strike 10° N. of W. The
shales do not appear to be equally fossiliferous throughout. In
some bands graptolites are abundant, while others appear to be
quite unfossiliferous. The fossiliferous bands yielded Monograptus
priodon, Bronn, M. vomerinus, Nich., M. personatus, Tullb., M.
flexuosus, Tullb., M. Hisingert, var. rigidus (?), Lapw., and Cyrto-
graptus sp.

Kast of Neckarmount the harder unfossiliferous bands are exposed,
at the top of a sudden rise of ground. Here the direction of strike
changes to 20° N. of W. This is evidently due to the presence of
the fault (F, 2), which is at this place in close proximity.

(ii.) Sections East of Fault (F. 2).

(a) Road-section.—As mentioned above, the Wenlock Shales are
faulted against the Tarannon Shales to the west. Unfortunately
the beds here are so deeply weathered that fossils are exceedingly
rare, but the change in the character of the rocks, in addition to
paleontological evidence, enables us to affirm with some certainty
that the beds are of Wenlock age. The only graptolites obtainable
were Monograptus vomerinus, Nich. (1 specimen), MZ. fleauosus,
Tullb. (1 specimen), and Cyrtograptus ? (1 specimen).

284 MISS G. L, ELLES AND MISS FE. M. R, WOOD on THR [May 1896,

(3) Hillside-sections—On the hillside, immediately above, the
exposures yielded several graptolites, belonging, however, to but
few species: Monograptus priodon, Bronn, M.. personatus, Tullb.,
M. vomerinus, Nich., and M. fleauosus, Tullb.

This exposure was traceable, with interruptions, round the hill to
above the lodge leading to Benarth Asylum.

(vy) Shore-section.—The section of Wenlock Shales exposed on the
shore at low tide is very complete. These beds first appear just
below the end of the lodge garden, and continue for some distance
along the shore. The lower beds are very shivery in character, but
as higher beds are reached they become more compact and finally pass
up into the hard flagstones with intercalated grit-bands belonging
to the series of Denbighshire Grits and Flags. The following
fossils were obtained :-——_Monograptus priodon, Bronn; M. personatus,
Tullb.; M. vomerinus, Nich.

4, The Denbighshire Grits and Flags.

The boundary-line between the Wenlock Shales and the Den-
bighshire Grits and Flags east of the fault (F. 2) is approximately
correct; but between this fault and the western limit exposures are
rare, and the boundary cannot be fixed with any accuracy. Quite
near the western fault exposures are more abundant, and the
alteration of strike near the line of disturbance is perfectly evident,

VY. CoRRELATION WITH OTHER AREAS,

1. The Llandovery Rocks.

The general character of the graptolites found on the bank of
the stream and in the road-section shows that the beds are nearly
related to the Upper Birkhill Shales of Southern Scotland, and also
to similar beds occurring in the Lake District and elsewhere.

We do not think that it is possible to trace at Conway all the
minuter subdivisions recognized at Moffat, but certainly our highest
band (No. 6 of the stream-section) corresponds with the uppermost
zone of the Birkhill Shales, namely with the zone of Lastrites
maximus. The bands below (Nos. 2 and 4) may subsequently be
found to be the equivalents of lower zones, but in the present state
of our knowledge it is wisest to say only that the beds contain
an Upper Birkhill fauna. The following table shows the species
common to the beds in various areas :-— :

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 285

CENTRAL
Conway. ScoTLaND, Lake District. Wiss.
Zone of ,
ae Upper | Middle | Upper
Llandovery Beds. pee Birkhill,| Skelgill, | Skelwill.

* Rastrites maximus (Carr.)......... * Re ieisonobs “ *
—— gemmatus (Barr.) . ..c.csceee] seeeee | serene A ee |
distans (Lapw.).........s0000 * Pe ec saiyes hl lecciady MM onpectad

peregrinus (Barr.)............ * * are linear *
* Monograptus argutus (Lapw.)...| ss... * ead a oe Ce ee
Eearrranii (Lullb.) sccrvesas| seswat.| |!) wesaee Wee Cheeta ww tee
* —___ concinnus (Lapw.).........0+ % * ee dA Lee eicr iy ad oe
Si icthcacbetebeaaahy “imap * * Sante me £
Crassus (Lapw.) ......s.s.000+- * Ry wears Rye de cnen
gregarius (Lapw.)..........6 * * * ROT Wa
— galaensis (Lapw.) ........... * HTT Wekee eth! WiaeeeS bat 1) wees.
—— Hisingert, var.nudus(Lapw.)| sexe | sexes | senses | senvee | sevece

—— involutus (Lapw.) ........060 * * * * *

* — lobiferus (M‘Ooy) ............ x * all oa hae *

—— runcinatus (Lapw.) .........] seeeee Da ase * *
spinigerus (Nich.) .......00+«- x Splut rer ied aewens [iy ° “daas oe

og turriculatus (Barr.) ......... * yen eee ee * %
Petalograptus ovatus (Barr.). * EWR Psst | “seabes
* Diplograptus Hughesii (Nich. yi, * * * Re NS con sbivi
* —___ nalmeus (Barr.) ...........008 * c oheind Wants a4 a SEs ee
— sinuatus (Nich.)............45. * * x BED Ue ica che
* — tamariscus (Nich.)............ x * * FERRO ach ae
* Climacograptus normalis (Lapw.) * * * ME e seks

As shown by this table, the correspondence between the fauna
of the Conway beds and that of the Upper Birkhill Shales is very
close. As the study of our fossil lists will show, the species are
by no means evenly distributed throughout the three bands.

Some forms, which are very rare in the zone of Rastrites maximus,
are far more characteristic: of the Tarannon Shales; such, for
instance, as’ Monograptus turriculatus, M. galaensis, M. pandus, and
M. Barrandit. Others occur more abundantly i in the lower bands
(2 and 4), and may indicate the presence of lower zones. Mono-
graptus gregarius is fairly common in band No. 2, but we have
succeeded in obtaining only one specimen from the zone of Rastrates
maximus.

Rastrites peregrinus was found only in the lowest band (No. 2).
The poverty of the fauna from this lowest band was no doubt in part
due to the very small extent of the exposure ; had we been enabled
to work it better, we probably should have found it possible to
definitely determine its age.

2. The Tarannon Shales.

The correlation of the lowest fossiliferous band of the Tarannon
Group is a matter of some difficulty. We did not succeed in finding

286 MISS G. L. BLLES AND MISS E. M. R. WooD ON THE [May 1896,

Monograptus turriculatus; but the fauna, on the whole, shows
affinities with the underlying and overlying beds, and we therefore
consider that it is of the nature of a passage-bed. We do not know
its exact equivalent in other areas.

The main mass of the Tarannon Shales may be correlated with
the lower of the two groups into which Prof. Lapworth (Ann.
& Mag. Nat. Hist. ser. 5, vols. v. & vi. 1880) has divided the Gala
rocks of the Southern Uplands of Scotland—that is, the zone of
Monograptus exiquus.

It does not seem possible to recognize here the two sub-zones
defined by Messrs. Marr and Nicholson (Quart. Journ. Geol. Soe.

vol. xliv. 1888, p. 654) in the Lake District. There they found’

(1) zone of Monograptus turriculatus (Barr.) and (2) zone of
M. crispus (Lapw.). In our beds M. turriculatus and M. eaiguus
range together throughout, but it is noticeable that the genus Retio-
lites is confined to the uppermost members of the series.

The following table shows the relation of the Tarannon Shales of
Conway to beds of similar age in the Lake District and Southern
Scotland :-—

Conway. Lake District. | Sovura Scornanp.
Tarannon Shales. Browgill Shales. Lower Gala.

* Monograpius Becki (Barr.) ...00:| nowns . *

broughtonensis (Nich.) ...... * wessate
* Graspus\(Tapw.)).isc.ecsecess * *
concunius (Lapw:).<.<cece ey Np meee: *
= exiguis (Nich.) ....0...-00s00- * *
—— Flemingii (Salt.) ....ccccceee] we nwee *
iqaiaensts (Uapw.) ....ccassees| em Moeecene *
Hlisingeri,var.nudus(Lapw.) * *
—— priodon (Bronn) ......cc000-| ee nnee #

A pandus (Lapw, )«<-4.seaeeeese <n a ae) eee
runcinatus, var. (Lapw.) ..-| eaes-e x

* Cyrtograptus spiralis (Gein.) ... * papa 8
Petalograptus ovatus (His.) ......| — aewnee *
palmeus (Barr.)...0.2eseeeee * *
Diplograptus tamariscus (Nich.)| se aeave *

* Retiolites Geinitzianus (Barr.)... ee: (ome.
a gbesws(Liapw.) ....:-seeeetae * x

It is interesting to note that several of the graptolites found in
the Tarannon Shales of Conway seem to be identical with many
Swedish forms of the same age. .

3. The Wenlock Shales.

The correlation of these beds is matter of no difficulty ; they seem
to be the equivalents of the Pen-y-glog Slates of the Dee Valley

—_

Vol. 52.] | LLANDOVERY AND ASSOCIATED ROCKS OF CONWAY. 287

(Lake, Quart. Journ. Geol. Soc. vol. li. 1895, p. 9), the Brathay
Flags of the Lake District (Marr, Geol. Mag. 1892, p.535), and the
Riccarton Flags of Scotland.

| LAKE

ScoTLAND.
District.

Conway. Derr VALLEY.

Pen-y-glog Brathay Riccarton

Wenlock Shale. Slates. Flags. Beds.
Monograptus priodon (Bronn). * * x
vomerinus, Nich. ........0+0. * * %
—— personatus (Tullb.)......... * *
Cyrtograptus Murchisoni (Carr.) * *

There also occurs at Conway Monograpius flewuosus, which is a
Swedish form of Wenlock Shale age.

4, The Denbighshire Grits and Flags.

The Denbighshire Grits and Flags, from their position above the
Wenlock Shales, are in all probability the equivalents of the beds
overlying the Pen-y-glog Slates in the Dee Valley, which Mr. Lake
has shown (op. cit.) to be of Lower Ludlow age.

Approximate Correlation of Beds.

CENTRAL WALES AND LAKE

TLAND.
WeEsTERN ENGLAND. DIstRIcT. Sco

Conway.

fe gdh | See eur us ies,
Denbighshire Grits | “Gob os Moel-Ferna | 4 Jawoll Bed
and Flags. Fl. io 35 Slates, and Pen- CHOW eens:
He y-glog Grit.

Wenlock Shales. | Wenlock Shales (Pen-y-glog Slate).) Brathay Flags. |Riccarton Flags.

(Upper beds absent.) | 1. Zone of Retiolites Geinitzianus,| Upper Browgill| Upper Gala
Beds.

C. Graye. Beds.
Tarannon Shales. | 2. Zone of Monograptus turricula-| Lower Browgill| Lower Gala
tus, M. exiguus, ete. Beds. Beds.

Upper Llandovery | Llandovery Beds of Cardigan and | Upper Skelgill | Upper Birkhill
Beds. Dee Valley. Shales. Shales,

288 LLANDOVERY AND ASSOCIATED ROCKS OF conway. [May 1896,

VI. Grnerat Conciustons.

From the facts brought forward in the present paper it is evident
that rocks of Llandovery age do occur in North Wales, and hence that
the stratigraphical break in that region between the Silurian and
Ordovician rocks is, at any rate, far less actually than has hitherto
been supposed.

The type of Llandovery rocks developed at Conway is more closely
related to that of Southern Scotland and Northern England than to
that of the typical Welsh Borderland area, and it is interesting to
observe that here, at any rate, deep-water conditions prevailed from
Upper Llandovery to Wenlock times.

With regard to the Tarannon Shales, Wenlock Shales, and
Denbighshire Grits and Flags, they differ in no essential respect
from those found in the Dee Valley, which have been recently shown
(Lake, Quart. Journ. Geol. Soc. vol. li. 1895, op. cit.) to be the
normal type, and therefore require no further comment.

Our best thanks are due to Mr. J. E. Marr, F.R.S., and Prof.
Charles Lapworth, F.R.S., for much kind help and assistance in our
work. .

Discussion,
The Presrpent said that the Authors of this paper had made

an exhaustive survey of a limited area, collecting the fossils and
correlating with care the graptolites from each horizon. ‘Such work

deserved the Society’s praise, as following the example of Prof. Lap-
worth and other careful workers. Such accurate field-work, coupled -

with careful paleontological results, was of the greatest value.

Dr. Hicks said that he had listened with much interest to the
paper, and he hoped the Authors would continue their researches
into other areas in North Wales, for it is highly important that the
fossil-zones in the beds forming the base of the Silurian in that area
should be clearly defined. He had not examined the sections referred
to by the Authors, but some years ago he found that the sandstones
on the eastern side of the Conway valley (towards Llanrwst) con-
tained Nematophycus and other fossils characteristic of the Pen-y-glog
Beds near Corwen. He would have liked to hear whether the
Authors considered that the deep-water beds of Upper Llandovery
age at Conway rested directly on the Bala Beds, and whether there
was an entire absence of the beds near Bula classed by Mr. Ruddy
as Lower Llandovery.

Mr. W. W. Warts congratulated the Authors on a most admirable
piece of work. He pointed out how the Upper Llandovery rocks had
been gradually recognized and extended. There was no gap between
those of Shropshire and of Conway, for the rocks had been recognized
on the Breiddens, near Meifod in Montgomeryshire, and in the
Berwyns. There appeared to be no evidence of conformity between
the Ordovician and Silurian rocks in the Conway district, in spite
of the fact that somewhat deep-sea beds had been found there.
He hoped that the Authors would recognize the Monograptus
colonus- and M., leintwardinensis-beds in the Denbighshire Grit.

Vol. 52.] - GLACIAL ACTION IN AUSTRALIA. 289

15. Evipences of Gracran Action in AvstRaLiA in PERMo-Carpo-
nirerous Time. By T. W. Eperworrn Davin, Esq., B.A.,
F.G.S8., Professor of Geology in the University of Sy dney.
(Read Bebriacy 5th, 1896.)

[Puate XII.)

Conrents.
Page
I. Work done by previous Observers ..........ssceseseeseseseevees 289
II. Latest Observations by the Author ...........cccccsceeseencesees 294
IIT. Correlation of the Glacial Deposits ...........-.4ecesscesesseeeee 298
Ven eCOviniGiial WOMMEEONG Mey nerdusivehessspbinse~ssopbennecsceveegsece 300

Tux subject of which this paper treats has already been traversed
by the author in his Presidential address to the Geological Section
of the Australasian Association for the Advancement of Science, at
its meeting at Brisbane in January 1895.

The author hopes, however, that the presentation to this Society
of a summary of these previous records,—with the addition of his
subsequent field-work in 1895,—will be justified by the opportunity
now given of a discussion which will be of immense benefit in
furthering an important and interesting branch of geological investi-
gation.

The personal observations recorded in this paper are the result of
13 years’, more or less constant, field-work in Australia.

I. Work DONE BY PREVIOUS OBSERVERS.

The first actual record of evidence of ice-action in Australia is
probably that made by Dr. A. R. C. Selwyn in 1859."

The statement is as follows:—‘ At one point in the bed of the
Inman I observed a smooth, striated, and grooved rock-surface
presenting every indication of glacial action. The bank of the
creek showed a section of clay and coarse gravel, or drift, composed
of fragments of all sizes irregularly interbedded through the clay.
The direction of the grooves and scratches is E. and W. in parallel
lines; and though they follow the course of the stream, I do not
think they could have been produced by the action of water forcing
pebbles and boulders detached from the drift along the bed of the
stream. This is the first and only instance of the kind I have met
with in Australia, and it at once attracted my attention, strongly
reminding me of the similar markings I had so frequently observed
in the mountain-valleys of North Wales.’

These very important observations appear to have been lost sight

. 1 Geological Notes of a Journey in South Australia from Cape Jarvis to
Mount Serle,’ by A. R. C. Selwyn, Parliamentary Paper, no. 20, Adelaide,
1859, p. 4.

290 : PROF. T, W. EDGEWORTH DAVID ON [May 1896,

of for about 35 years, and Australian geologists have not yet had an
opportunity of confirming them; but the subsequent discoveries
in this neighbourhood by Prof. Ralph Tate, of Adelaide University,
leave no doubt as to their accuracy.

In 1860 the Rev. W. B. Clarke’ recorded the existence of a few
‘blocs perchés’ in the Australian Alps.

In 1866 Sir Richard Daintree* recorded evidences of ice-action
in the districts of Bacchus Marsh and Ballan, in Victoria, in these
words :—‘ Here [on the Lerderberg River, Bacchus Marsh, Vic-
toria] I have found a few pebbles grooved in the manner I have
read of as caused by glacial action.’

This observation has been confirmed by several geological workers,
including the present author ; and glaciated boulders from near this
locality were exhibited at the meeting when this paper was read.

In 1877 Prof. Ralph Tate* discovered a glaciated rock-pavement
capped by glacial beds at Hallett’s Cove, near Adelaide, and on
May 7th of that year he recorded his discovery in a course of public
lectures. The glaciated rock-pavement is described as being of
Archean age and as forming the summit of the sea-cliffs for a dis-
tance of about a mile in a N. and S. direction, with a width of a
few yards, and as terminating inland against a low mural escarpment
of Miocene limestone. Recent observations by Mr. A. W. How-
chin, Prof. Ralph Tate, and the author, show that this pavement
extends for at least 7 mile under the Miocene limestone. The
glacial beds which intervene between the pavement and the Miocene
limestone are stated to contain blocks of rock derived from an area
about 35 miles to the south. The pavement is described as being
smoothed and striated in a north-and-south direction, and as
showing evidence that the ice which caused the striation came
from the south.

In 1879 Mr. R. L. Jack* recorded his discovery of blocks of
granite, slate, etc., contemporaneously embedded in strata of Permo-
Carboniferous age, in the Bowen River Coalfield, Queensland. The
presence of these blocks is attributed by Mr. Jack to the action
of floating ice.

In 1879 the late Mr. C. 8. Wilkinson ’ recorded what he con-
sidered to be evidence of glacial action in the Triassic Hawkesbury
Series of New South Wales. This evidence consists of disrupted
masses of clay-shale, of all sizes up to 20 feet in diameter, embedded
in sandstone.

1 «Researches in the Southern Goldfields of New South Wales, Sydney,
1860, p. 225.

2 Geological Survey of Victoria. ‘ Report on the Geology of the District of
Ballan, including Remarks on the Age and Origin of Gold, ete.’ By Richard
Daintree. Melbourne, 1866.

3 See Rep. Austr. Assoc. Adv. Science, vol. i. pp. 231-232, Sydney, 1887;
ibid. vol. v. p. 31, Adelaide, 1893; also Trans. Roy. Soc. S. Austr. vol. ii. 1879,

. Ixiv.

4 «Report on the Bowen River Coalfield,’ by Robert L. Jack, p. 7, par. 39.
Brisbane, 1879.

5 Journ. Roy. Soc. N. 8S. Wales, vol. xiii. 1879, ‘Notes on the Occurrence of
remarkable Boulders in the Hawkesbury Rocks,’ pp. 105-107.

Vol. 52. | GLACIAL ACTION IN AUSTRALIA. 291

In 1884 Mr. R. M. Johnston! of Tasmania described the occurrence
of erratics, some over a ton in weight, in the Permo-Carboniferous
rocks of Maria Island, Tasmania.

In 1885 Mr. R. D. Oldham? visited Branxton in New South
Wales (where Mr. C. S. Wilkinson had the previous year discovered
some large erratics), and found one small boulder which he described
as being unmistakably striated and polished by ice. This deposit
is of Permo-Carboniferous age, and probably homotaxial with the
erratic-beds of the Bowen River Coalfield, Queensland, and those
of similar age in Tasmania. Mr. Oldham correlates the Branxton
beds with those of Bacchus Marsh in Victoria, and suggests that
they may be the equivalents of the Talchirs of India. He also
suggests that during the deposition of these beds ‘there was a
widespread glacial epoch corresponding to that which is known to
have occurred in post-Tertiary time.’

In 1886 Mr. R. M. Johnston® recorded further evidence of erratics
in Permo-Carboniferous rocks at One Tree Point, Bruni Island,
Tasmania. They are embedded in marine strata with which is
associated Gangamopteris spathulata, M‘Coy.

In 1887 the author * recorded the occurrence of numerous erratics
in Permo-Carboniferous strata at Grasstree in New South Wales.

They are mostly rounded, seldom angular; none observed were
distinctly glaciated, though many were faintly striated, possibly
through earth-movements. About the same time the author
observed, near Branxton, a block of granite nearly a ton in weight,
embedded in the Permo-Carboniferous strata in such a position as
to leave no other explanation possible than that it had been dropped
from floating ice. (A photograph of this was exhibited at the
meeting. )

In 1890 the late Dr. Feistmantel’ correlated the Bacchus Marsh
Beds of Victoria and the Upper and Lower Marine Beds of New
South Wales with the Dwyka Conglomerates of Southern Africa, and
with the Talchir Boulder-beds of India. The Productus-limestone
which in the Salt Range caps the Talchir Boulder-beds afforded
palzontological evidence for the above correlation.

Feistmantel summarizes the evidence as follows :—‘ This circum-
stance [the occurrence of ice-scratched boulders in the strata]
would, of course, indicate a rather general change of climatic
conditions over Australia, portions of Africa, India, etc. towards the
close of the Carboniferous epoch. But I do not think that it was
contemporaneous over that whole region, and it appears to me that
it set in first in Eastern Australia (New South Wales), destroying

1 Proc. Roy. Soc. Tasmania, 1884, p. lxv.

2 Rec. Geol. Surv. India, vol. xix. pt. i. p. 44.

3 Proc. Roy. Soc. Tasmania, 1886, pp. 23-24.

4 ‘Hvidence of Glacial Action in the Carboniferous and Hawkesbury Series in
N.S. Wales,’ Quart. Journ. Geol. Soc. vol. xliii. pp. 190-196.

5 «The Geological and Paleontological Relations of the Coal- and Plant-
bearing Beds of Paleozoic and Mesozoic Age in E. Australia and Tasmania,’
Mem. Geol. Surv. N.S. W. Pal. No. 3, pp. 46, 47, 181.

Q.J.G.8. No. 206. x

292 PROF. T. W. EDGEWORTH DAVID ON [May 1896,

the Carboniferous flora at an early date, while in Southern Africa
we find still a Carboniferous or Coal-Measure flora of a higher
stage, and only hereafter the change of climate appears to have taken
place there. When the conditions of ice-action ceased, there ap-
peared in Africa, India, Victoria, New South Wales, etc., a luxuriant
flora of a peculiar character, which was, however, foreshadowed by a
few forms in the Lower Coal Measures in New South Wales. In this
period falls the deposition of the Karoo Formation in Africa, the
Gondwana System in India, the Newcastle Beds, etc., in New South
Wales, the Bacchus Marsh Beds in Victoria, and so on.’

In 1890 Mr. E. J. Dunn”* published a very important paper on
the glacial conglomerates of Victoria. He showed that they were
widely distributed on either side of the Main Dividing Range of
Victoria, Wild Duck Creek near Heathcote to the north, and
Bacchus Marsh to the south, being the principal localities. He
described the glacial conglomerates as consisting of fragments of
rock up to 30 tons in weight, mostly well rounded, frequently
polished, strongly striated, grooved and faceted, more rarely angular,
embedded in a groundmass of a prevailing dark grey colour. The
rocks constituting the boulders are stated to be for the most part
foreign to the district. Mr. Dunn says (op. cit. p. 456), ‘No other
conclusion can be arrived at than that floating ice has been the
agent by which the material has been brought into its present
position .... Tasmania may have furnished some of them’ [2. e. the
erratics |.

In 1891 Mr. G. B. Pritchard * recorded the occurrence of glaciated
rock-surfaces at a spot to the north of the township of Curramulka,
on the eastern side of Yorke Peninsula, South Australia. This
evidence can be confidently correlated with that previously dis-
covered by Prof. Ralph Tate at Hallett’s Cove.

In 1892 Mr. E. J. Dunn * published another important and well-
illustrated report relating specially to the glacial deposits of Wild
Duck Creek. Mr. Dunn recorded therein his discovery of a strongly
glaciated rock-surface near Wild Duck Creek, the strie trending
north and south. The altitude of the upper portion of the glacial
eonglomerate is stated to be about 700 feet above the sea.

In 1892 Messrs. Dunn and T. B. Moore* published evidence of a
glacial conglomerate, 3000 feet above sea-level, near Zeehan in
‘Tasmania. ‘The included boulders were found to be beautifully
striated. This formation should, in Mr. Dunn’s opinion, be corre-
lated with that of Bacchus Marsh.

In 1893 Mr. T. B. Moore’ recorded the occurrence at Mount
Tyndall of a glacial conglomerate, considered by him to be of

1 Rep. Austr. Assoc. Adv. Science, vol. ii. pp. 452-456, Melbourne, 1890.

? Trans. Roy. Soc. South Australia, vol. xv. (1891-92) p. 182.

* “Notes on the Glacial Conglomerate, Wild Duck Creek,’ by E. J. Dunn,
¥.G.S. ; Special Reports, Department of Mines, Victoria. Melbourne, 1892.

* Proc. Roy. Soc. Victoria, n. s. vol. vi. (1894) pp. 133-188, pl. viii.

® ‘Discovery of Glaciation in the Vicinity of Mount Tyndall, in Tasmania,’
by T. B. Moore, Proc. Roy. Soc. Tasmania, 1893, pp. 147-149.

‘Vol. 52.] GLACIAL ACTION IN AUSTRALIA, 293

-the same geological age as that already referred to near Zeehan.
Its altitude was estimated to be 3500 feet.

In 1893 Mr. A. Montgomery questioned the accuracy of Mr. T.
B. Moore’s determination of the geological age of the glacial con-
glomerate at Mount Tyndall as being Permo-Carboniferous, and
suggested that it might be a re-distributed Permo-Carboniferous
conglomerate glaciated perhaps in Tertiary time.

In 1893 Messrs. Graham Officer and L. Balfour’ published an
account, well illustrated, of the Bacchus Marsh conglomerates.
‘They considered the glacial conglomerates referable to two distinct
epochs, one belonging to Permo-Carboniferous, the other to Tertiary
time. In a subsequent paper,” however, they withdrew their
opinion as to the evidence in this neighbourhood of any Tertiary
glaciation.

In September 1893 Messrs. G. Sweet and C. C. Brittlebank ®
published an important paper on the glacial deposits of the Bacchus
Marsh district. They proved satisfactorily, in the author’s opinion,
that none of the glacial deposits there observable were referable to
‘Tertiary time, but all belonged either to a late Paleozoic or early
Mesozoic age. They described the glaciated rock-surfaces previously
discovered by Messrs. Brittlebank and Graham Officer, quoting evi-
dence to show that the striz trend from S.W. towards N.E., and that
the ice which produced them moved in a north-easterly direction.
They estimated the thickness of the glacial beds at about 5000 feet,
and determined their elevations as ranging from about 700 to 1400
feet above the sea. The sandstones near the top of the glacial series
contain Gangamopteris angustifolius, M‘Coy, G. obliqua, M‘Coy, and
G. spathulata, M‘Coy, while in shaly sandstones on a somewhat
higher horizon fragments of plants resembling Schizoneura, Zeugo-
phyllites, etc., have been observed.*

In November 1894 Mr. T. 8. Hall’ contributed a note on the
bibliography of the Bacchus Marsh Glacial Deposits.

In January 1895 the author submitted the report by Prof.
Ralph Tate, Mr. Walter Howchin, and himself on the Evidences of
‘Glacial Action at Hallett’s Cove to the Australasian Association for
the Advancement of Science. This is published in the volume for
1895 issued by the Association. On April 3rd, 1895, Mr. Walter
Howchin contributed a paper on the same locality,® in which he
gives a detailed account of the glacial phenomena, and arrives at
provisional deductions.

' Proc. Roy. Soc. Victoria, n. s. vol. v. (1893) pp. 45-68, pls. x.—xii.

2 Ibid, n. 8. vol. vi. (1894) pp. 1389-148.

° Rep. Austr. Assoc. Adv. Science, vol. v. pp. 376-389, Adelaide, 1893.

* Annual Report of the Secretary for Mines, Victoria, for the year 1893,
pp. 18-19. Melbourne, 1894.

° ‘The Victorian Naturalist,’ Melbourne, 1894, pp. 125-128.

® Trans. Roy. Soc. South Australia, vol. xix. pt. i. pp. 61-69.

per

294 PROF, T. W. EDGEWORTH DAVID ON [May 1896;.

Il. Largest OBSERVATIONS BY THE AUTHOR.

(a) Hallett’s Cove.

In December 1894 the author visited Hallett’s Cove, near Adelaide,
in company with Prof. Ralph Tate and Mr. A. W. Howchin, with
the view of determining the question as to whether the glacia-
tion was post-Miocene or pre-Miocene. This question had been
discussed on the ground, during the meeting of the Australasian
Association for the Advancement of Science at Adelaide in 1893, by
Prof. Ralph Tate and a party of the members. For the purpose of
finally settling the question, the Association placed the sum of £20
at the disposal of the members of their Glacial Committee, to enable
them to cut a trench from the glaciated rock-pavement, across the:
outcropping edges of the glacial beds, up to the base of the Miocene
limestone. ‘Trenches were cut under the supervision of the above-
mentioned members of the Committee, and with the permission of
Mr. W. Reynell, and these excavations proved conclusively that the
glaciation was pre-Miocene. These results have already been
communicated by the Glacial Committee to the Australasian Asso-
ciation for the Advancement of Science. Briefly summarized, the
Report is as follows :—

The formations represented at Hallett’s Cove are :—

1. Pre-Cambrian rocks, consisting of hard, purplish-red clay-
slates with greenish bands, grey quartzites, and thin bands:
of siliceous limestone. The prevalent dip is W. 10° to 20°N.
at from 40° to 78°. Wherever a fresh surface of these rocks
has been exposed by the denudation of the overlying glacial
beds, it is seen to be smooth and strongly glaciated, the striz
being sharply cut and as freshly preserved as though they
had resulted from recent glacial action. Their trend is
nearly north and south, and it is clear that the ice which
produced them came from the south. The glaciated surface
ascends to about 100 feet above sea-level, and descends to
probably a considerable depth below the sea-level. The
length of the glaciated surface preserved is about 1 mile,
and its width about 3 mile.

2. Glacial Beds, consisting of reddish-brown clay-slates, sandy
in places, and fairly well stratified, especially in their upper
portion. Downward they pass into sandy, greyish-brown
mudstones, containing well-striated boulders in abundance:
the latter occur only sparingly in the upper portion of the
deposit. Erratics, chiefly of porphyritic granite, and up to 8
tons in weight, are embedded in the strata at intervals. They
belong chiefly to a variety of granite occurring in place (diavt
R. Tate) at Port Victor, 35 miles south. The glacial beds are
from 23 to more than 100 feet thick, descend below sea-level,
and ascend to over 100 feet above the sea. No trace of any

1 Rep. Austr. Assoc. Ady. Science, Brisbane, 1895.

Vol. 52.] GLACIAL ACTION IN AUSTRALIA. 295

organism has yet been met with in these beds. The matrix
has evidently been derived from the wearing away of the
local pre-Cambrian rocks, whereas many of the erratics are
foreign to the neighbourhood.

3. Miocene limestone and Miocene (?) clays. The former is
separated by a slight unconformity from the underlying
glacial beds. It varies in composition from that of an
arenaceous limestone to that of a calcareous sandstone,
having a thickness of from 2 to 3 feet. The following are
some of the marine fossils contained in it, as determined by
Prof. Ralph Tate :—Plestastraa St.-Vincenti, Ten. Woods,
Pecten spondyloides, Tate, Mytilus submenkeanus, Tate, Pec-
tunculus convexus, Tate, Conotrochus typus (Seguenza ?).
The limestone passes upward into clays, perhaps also of
Miocene age, and about 60 feet in thickness.

A, Recent (?) nodular travertine, about 3 to 4 feet thick.

5. Blown sand and beach sand, resting successively on all the
preceding formations.

It may be concluded that, as proved by the transport of the erratics
and the grooving of the rock-pavements, the ice which produced the
glaciation moved from south to north, and that it was of an age inter-
mediate between Miocene and Pre-Cambrian. The comparatively
slight induration of the glacial beds and remarkable freshness of
the strive suggest that the glaciation did not antedate the close of
the Paleozoic era, as all rocks older than this in Australia are
£onsiderably indurated.

(6) Wild Duck Creek, Derrinal, near Heathcote.

The formations here represented are :—

1. Lower Silurian (Ordovician), which in places exhibit strongly
grooved polished surfaces, the trend of the grooves being
from §. 5° E. towards N. 5° W.

2. Permo-Carboniferous Glacial Beds, consisting chiefly of mud-
stones, with erratics up to 30 tons in weight, and sandstones.
Nearly all the erratics and small boulders are beautifully
glaciated, being grooved, polished, and faceted. The beds have
been traced by Mr. Dunn for 153 miles in a north and south
direction, and they have a width of 5 miles. They attain an
elevation of about 750 feet above the sea, and have a thick-
ness of probably at least 300 or 400 feet. Both Mr. Dunn
and Mr. A. W. Howchin are of opinion that the erratics re-
semble the rocks of North Gippsland in Victoria, the age of
which ranges from Silurian to Carboniferous. Here, as at
Hallett’s Cove, the glaciation of the rock-pavements shows
that the ice probably came from the south. (Photographs
of the glaciated Lower Silurian rock and of the large erratic
known as ‘ The Stranger’ were exhibited at the meeting.)

296 PROF. T. W. EDGEWORTH DAVID ON [May 1896,.

(c) Bacchus Marsh.

This district was examined by the author in company with
Messrs. G. Sweet and Charles C. Brittlebank during December 1894,
and again by the author in company with Messrs. C. C. Brittle-
bank, T. Brittlebank, Graham Officer, and L. Balfour, during
December 1895, The formations represented were as follows :—

1. Lower Silurian (Ordovician), black slates and shales, with
graptolites and grey quartzites intruded in places by granite.
The strike is N. 10° E. to N.E., and they dip at a high
angle. Wherever their surface has been freshly exposed in
this neighbourhood it is seen to be strongly grooved and.
polished, and more or less moutonnée. Such striated pave-
ments have been traced by Messrs. Sweet and Brittlebank at
intervals over an area of 130 square miles in this district ;
and later observations by Messrs. Officer and Balfour in the
Coimadai district have proved the area to be much greater.
In places where the Ordovician clay-slates have had their
glaciated surface destroyed by denudation, an exquisite cast
of it is preserved on the under-surface of the glacial beds,.
accurate impressions being retained of even the most minute.
strie. The surface of the pavement is very uneven, being
traversed by troughs from 500 to 600 feet deep, the slopes:
of the ridges separating the troughs one from another being
sometimes as steep as 70°. The bottoms of the troughs and.
the slopes and summits of the ridges are all strongly glaciated.
The author agrees with Messrs. Sweet, Brittlebank, Graham.
Officer, and L. Balfour in their inference that the ice which.
produced the glaciation came from the south... At the Wer-

-ribee Gorge the strie trend from about 8. 12° W. to N. 12° KE.

2. Permo-Carboniferous Glacial Beds.—The thickness of these
rocks has been approximately estimated, as already stated,.
by Messrs. Sweet and Brittlebank to be about 50006 feet, and
on the occasion of the author’s first examination of them it.
appeared that this estimate of them was not excessive..
Measurements, however, taken by Messrs. Chas. C. Brittle-
bank, T. Brittlebank, Graham Officer, L. Balfour, and the
author last December show that the thickness may perhaps
have been over-estimated through a repetition of the beds-
resulting from faulting or folding. Their general dip is:
rather steep, varying from about 15° up to 60°. They con-
sist of :—(i) Hard and soft mudstones, from brownish-grey
to light claret in colour, bluish-grey at a depth. A small
proportion of fragments of undecomposed felspar is present,.
together with minute chips of black shale (Lower Silurian ?).
and small pieces of carbonized plants. The soft mudstones.
are chiefly composed of clayey material, with quartz-grains,.
mostly subangular, and contain glaciated erratics sparingly.
The hard mudstones contain very numerous strongly-
glaciated boulders, frequently flattened on one side as though.

Vol.*52.] GLACIAL ACTION IN AUSTRALIA. 297

they had been rasped away by the ice; their diameter varies
from a few inches to 53 feet, but most of them measure less
than a foot in diameter. They are very firmly embedded
in the matrix, so that they can be dislodged only by repeated
blows from a heavy hammer. (Several fine specimens of
these glaciated blocks were exhibited, including one brought
by the author as a donation from Mr. C. C. Brittlebank to
the British Museum. See the accompanying figure.) The

Glaciated Boulder from the Permo-Carboniferous of Dunbar,
near Bacchus Marsh, Victoria. (About 4 natural size.)

[Reproduced from a photograph. |

maximum thickness of any individual bed measured proved
to be 193 feet.

(ii) Conglomerates.—Greenish brown, lithologically very
like those of the Permo-Carboniferous Newcastle Beds in
New South Wales. They are composed of well-rolled pebbles
from 1 to about 6 inches in diameter, with occasionally
large glaciated erratics. The thickness of individual beds
of conglomerate varies from a few feet up to about 20.
In places they make a very uneven junction-line with the
strata below them, as though they had been squeezed down
into these so as to occupy irregularly-shaped pockets.
In places the upper surface of the conglomerate is much
indented, as at the elbow of Myrniong Creek, about 4 mile
below Dunbar (the residence of Mr. Brittlebank).

298 PROF. T. W. EDGEWORTH DAVID ON [May 1896,

(iii) Sandstones.—These vary from hard to soft, from
fine to coarse, and are frequently laminated, the lamin
occasionally showing distinct evidence of contortion, espe-
cially in the neighbourhood of the irregular pockets of
conglomerate. Individual beds vary in thickness from a
few feet to nearly 100, being mostly about 30 feet thick.
Well- preserved plant-remains are present on at least
two horizons; on the lower horizon occur the three species
of Gangamopteris already referred to, and on the higher
specimens of Zeugophyllites, Schizoneura, ete. The total
thickness of the glacial beds seen in the upper portion of
Korkuperrimal Creek, as measured last December, proved to
be 1427 feet. To this, Mr. Brittlebank estimates, a thickness
of about 700 feet of strata should be added to carry the
section from the top of the Gangamopteris-beds to the top
of the strata seen above the Schizoneura-horizon. (The
order of succession of the beds is illustrated in the accom-
panying horizontal and vertical sections, Pl. XII.)

The altitude of the glacial beds varies from 600 to about 1400
feet above sea-level. The source of the erratics is not known, but
evidence shows that the ice which furrowed the rocks came, as
already stated, from the south.

The most northerly point to which drift containing undoubtedly
glaciated boulders has been traced is Springhurst, on the main
railway-line between Melbourne and Sydney, at the boundary
between Victoria and New South Wales.

TIT. Correnation oF THE GLACIAL DeEpostts.
(a) Australasian.

It is extremely probable that the glacial beds of Bacchus Marsh,
Wild Duck Creek, and Springhurst in Victoria were of homotaxial,
if not of contemporaneous origin. They may probably be correlated
with the glacial conglomerates of Mount Reid and Mount Tyndall
in Tasmania.

The above correlations are based chiefly on lithological evidence ;
there is, however, good paleontological evidence for the correlation
of the Bacchus Marsh glacial beds with the erratic-bearing Permo-
Carboniferous mudstones of Maria Island, One Tree Point, and
Bruni Island in Tasmania, the similar beds at Maitland, Branxton,
and Grasstree in New South Wales, and those of the Bowen River
Coalfield in Queensland, as the genus Gangamopteris is distributed
abundantly throughout the formations at all these localities. The
glacial evidences at Hallett’s Cove and at Curramulka in South
Australia may safely be correlated one with another, and are very
likely homotaxial with the above-mentioned glacial deposits in East
Australia and Tasmania.

‘Vol. 52.] GLACIAL ACTION IN AUSTRALIA. 299

(6) Extra-Australasian.

The Permo-Carboniferous glaciation of Australia and Tasmania
‘was perhaps homotaxial with that of Southern Africa and India.
In Southern Africa Mr. G. W. Stow and Dr. Sutherland have
described glaciated blocks associated with the Karoo or Ecca Beds.
Mr. E. J. Dunn in 1872 discovered glacial conglomerates, the
Dwyka Conglomerates, at Weltevreden Farm, near the junction of
the Vaal and Orange Rivers; moreover, he has told me that in
1885 he discovered a striated pavement at the junction of these
rivers, and was of opinion that the movement of the ice had been
from south to north. This pavement is less than 1000 feet above
the sea. The shales underlying the large boulders in the con-
glomerate are described by him as being distinctly indented. This
is in lat. 29° S., long. about 23° 40’ E. Mr. Dunn has also told
me that he found a specimen of Gangamopteris 5 inches in length
in the Lower Karoo Beds above the Dwyka Conglomerates.

In India evidence of glacial action in Permo-Carboniferous time
was first observed by Dr. W. T. Blanford, and subsequently similar
evidence has been collected by many other observers in the Talchir
Group, the Salt Range Group, the boulder-beds at Bap in Western
Rajputana, and the Panjéh Conglomerates of Kashmir.’

Mr. Fedden * states that at Irai, near Chanda, the Talchir Boulder-
beds rest upon compact Pem Limestones. His statement is as
follows :—‘ For a length of 330 yards along the river’s bank this
underlying rock is exposed, displaying a large surface, polished,
scratched, and grooved after the fashion so familiar to glacialists.
The surface has a slope of 12°-15° to the west, obliquely overcutting
the strata, which have a dip of 8° to the west-south-west. The
Striz and grooves run in long parallel lines, having directions be-
tween north-east and north-north-east, oblique to the slope of the
surface; and, from the manner in which the rock is affected at the
edges of the few planes of jointing, it can be inferred that the move-

ment was up the slope...... The actual conditions are so far con-
firmatory of the view we have been led to—of an ice-raft being
drifted against and impelled up an opposing rock-surface...... It

would appear that the freighted ice-mass had travelled a long
distance from the south-west through the Utnur and Edlabad
(Idulabad) districts, where rocks occur of the same composition as
that of the several boulders.’

‘The latitude of Irai is 19° 53', elevation under 900 feet; the
most southerly position of the Talchir Boulder-bed is stated to be
latitude 17° 20’, and its altitude is given as only a little above the
level of the sea,

Near Pokaran a similarly-glaciated pavement is stated to exhibit

1 «Geology of India,’ 2nd ed. 1893, Stratigraphical and Structural,
R. D. Oldham, pp. 120-121, 124, 135, 157-160, 198-201, ete. T. Oldham,
Mem. Geol. Surv. India, vol. ix. (1872) p. 324; and W. T. Blanford, bid.
pp. 321-325.

2 Rec. Geol. Sury. India, vol. viii. (1875) p. 17.

300 PROF. T. W. EDGEWORTH DAVID ON [May 1896,

in addition typical roches moutonnées (R. D. Oldham, op. cit. p. 160).
The marine fauna associated with the Boulder-beds of the Salt
Range, and partly underlying, partly overlying them, suggests that.
they may be homotaxial with those of Eastern Australia and
Tasmania.

This short summary of references to evidence of Permo-Car-
boniferous ice-action in Africa and India shows that the glacial
phenomena in those regions may probably be correlated on physical
and paleontological grounds with those already described as:
occurring in Australia, and the recent discovery of rocks of Lower
Gondwana age at Bajo de Velis, in Argentina,' renders it not
improbable that the evidences of glacial action which are recorded
as having been observed in Brazil may be homotaxial with those of
Southern Africa, India, Australia, and Tasmania.

LV. PRovistonaAL DEDUCTIONS.

If the correlation suggested for the Australasian glacial beds be
admissible, it is probable that ice-action of some kind was taking.
place over a large area of the Australasian region in Permo-
Carboniferous time. This region extended at least from Zeehan
in Tasmania, in lat. 42° 8., to the Bowen River Coalfield in
Queensland, in lat. 20° 30'S., and from long. about 137° 30’ E.
(Curramulka) to about 151° 30’ HE. (Maitland). In Victoria many
hundreds certainly, and probably several thousands, of square miles
are still occupied by glacial beds, and it is likely that very large
areas once glaciated have had all traces of glaciation effaced by
denudation.

The fauna and flora associated with the Permo-Carboniferous:
glacial beds of Australia render it probable that these glacial beds.
are homotaxial with the Dwyka glacial beds of Southern Africa and
the Talchir Boulder-beds of India. In the case of Australia, Southern.
Africa, and India, the general direction in which the ice moved
appears to have been from south to north. In Australia the thick-
ness of the glacial beds (unparalleled, so far as the author is aware,
in any other part of the world, being about 2000 feet, if the inter-
calated beds of sandstone and conglomerate are included in the
estimate) implies that the Permo-Carboniferous glacial epoch in the
Southern Hemisphere was of prolonged duration. This inference
is supported by the fact that in New South Wales a group of Coal:
Measures, over 230 feet thick, and comprising from 20 to 40 feet in
thickness of coal (the Greta Coal Measures), is sandwiched in
between the erratic-bearing horizon of the Lower Marine Series.
and the similar horizon of the Upper Marine Series.

As will be seen from the vertical section accompanying this paper
(Pl. XII.), there is evidence at Bacchus Marsh of at least from nine to
ten distinct boulder-bed horizons, separated one from another by thick
deposits of sandstone and conglomerate. The exact significance of

1 Rec. Geol. Surv. Ind. vol. xxviii. pt. iii. (1895) pp. 111-117, and Revista del.
Museo de la Plata, vol. vi. pp. 117 e¢ segg. - .

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Horizontal Scale

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le i i sn lr 8 et in lal il ala in ean ett cipan pinatictuaaarlii a ent mihaccma

Vol. 52.] GLACIAL ACTION IN AUSTRALIA. 301

these lithological breaks in the succession of strata is not yet under-
stood, but they may possibly indicate a sequence of glacial epochs
separated by milder interglacial periods. Possibly glacial conditions
in Australia may have been prolonged from late Paleozoic into early
Mesozoic time, as may perhaps be argued from the presence of plants
of Mesozoic facies, such as Schizoneura and Zeugophyllites, in the
uppermost glacial beds of Bacchus Marsh, and also perhaps from the
disrupted masses of clay-slates and contemporaneously-contorted
current-bedding in the Triassic Hawkesbury Series of New South
Wales.

EXPLANATION OF PLATE XII.

Horizontal and vertical sections of the Permo-Carboniferous Glacial Beds
at Bacchus Marsh (Victoria).

Discussion.

Dr. Buanrorp referred to the peculiar interest that he took in
the paper, as he had, nearly 40 years ago, called attention to the
existence in India of rocks similar to those described in Australia,
and of the same age, and had suggested a glacial origin for
them. He heartily congratulated the Author on his admirable paper
and on the conclusive evidence of glacial action now brought forward,
evidence so clear that it was doubtful whether a sceptic remained
among those who had attended the meeting. The speaker pro-
ceeded to give a few details of the progress of discovery in India,
and referring to the evidence gradually accumulated from Australia
and South Africa, especially noticed how in the Argentine Republic
of South America all the peculiar Upper Paleozoic and Mesozoic
floras of Australia—the Carboniferous flora with Lepidodendron and
Rhacopteris,the Permo-Carboniferous with Glossopteris and Gangamo-
pteris, and the Lower Mesozoic with Thinnfeldia odontopteroides—had
been discovered one after another, and how their constant associates:
in other lands, the boulder-beds, appear to have been found by
Prof. Derby in Southern Brazil. He pointed out the connexion
between these discoveries and the question of the former distribution
of land, and called attention to a recent paper by Mojsisovics,
Waagen, and Diener, who showed that while the present contours
of the Pacific Ocean were of pre-Triassic age, those of the Indian
and Atlantic Oceans appeared to be of later origin.

Mr. Wicxnam Kine and Prof. Bonney also spoke, and the AvrHor
replied.

302 REV. E. HILL ON TRANSPORTED BOULDER CLAY. [May 1896,

16. On TransportED BovuLpER Cray. By the Rev. Enpwin H11,
M.A., F.G.S. (Read January 22nd, 1896.)

I wish to put on record some facts lately observed respecting
two groups of Boulder-Clay masses which appear to have been trans-
ported from their original positions.

One group occurs in the cliffs south of Great Yarmouth. The sands
of the cliffs which extend from Lowestoft to Yarmouth are usually
described as ‘ Mid-Glacial.’ On them lies Chalky Boulder Clay as
seen at Corton and northwards, while below them are seen at several
spots a perfectly different stony clay, the sands called Pebbly Sands
or Westleton Beds, and the well-known Rootlet Bed. The Chalky
Boulder Clay extends continuously above the Mid-Glacial sands,
from Corton for about 2? mile northwards ; farther on, one or two
disconnected strips also he on the top of the cliffs. But, besides
these, several masses of the same material occur embedded in the
sands. I first noticed them while examining the coast in 1893,
and in the spring of 1895 I again made a careful inspection, this
time in company with Prof. Bonney. ‘Two lie one on either side of
the depression called League Hole, and others were seen respectively
about 4 mile, 1 mile, and 14 mile north, towards Gorleston. The
writer of the Survey Memoir (Mr. J. H. Blake) had his attention
attracted to these or similar masses, and remarks that ‘ at times
they looked as if they were lenticular patches of Boulder Clay in
the Glacial Sands’ (p. 56, Geology of Country near Yarmouth and
Lowestoft). He decided, however, that ‘they were all introduced
after the deposition of the sands.’ He does not explain how;
probably he means that they had fallen from the top of the wasting
cliff, and had become buried in talus or blown sand. If he had
seen the sections exposed in 1893 and 1895, I think he would have
concluded that they really were what he then saw that they looked
like.

The mass about 2 miles south of Gorleston Pier, or 4 mile north of
League Hole, as seen in the cliff-section, was about 4 feet thick,
with 40 feet of visible length (see fig. 1). Its northern end was
hidden by talus, but on the south it was seen, in a clean section
of the cliff, ending abruptly against the sands, which presented
their regular stratified appearance, and were in undisturbed con-
tact with it above and below. It was normal Chalky Boulder
Clay, crowded with fragments of chalk. The mass about 13 mile
south of Gorleston Pier had a very dark matrix, full of rather
rounded chalk pieces of all sizes, from a foot long down to the finest
grains; it contained also some larger inclusions of sand or silt.
This mass was about 6 feet thick, also with visible stratified sands
above and below. Here, too, one end was hidden under talus; the
other passed into the sands in tongues and strings of dark mud, but
the termination of these was again hidden by talus. The mass
about 1 mile south of Gorleston was some 30 feet long; one end

303

REV. E. HILL ON TRANSPORTED BOULDER CLAY.

Wor 52. |
Fig. 1.—WSection 3 mile north of League Hole.
atlanta

oe

Nee = ee

SS

Se

ES EE

SS eee

SSS

SS SSS
ity ee Wak

i)

ihe ee ate

A-B = about 4 feet. C = talus.
extending horizontally to the right for about
-bedded sand, with little lumps

The dotted part is Boulder Clay,
Above and to the left of B, fine
More disturbed in the upper part.

20 feet.
of Boulder Clay in it.

Fig. 2.—Section immediately north of League Hole.
(Total height = about 18 feet.)

Clay mixedjwith débris’
--{:----Loam about 2 feet
-Sandy Bed about 7 foot

ot SS \SNe 77,
> >
Mh

=— —_—_—., oer
(Looking north. |

304 REY. E. HILL ON TRANSPORTED BOULDER OLAY. [May 1806,

is bent up, and both ends thin out; it is only 6 feet below the
top of the cliff, and there is a layer of large flints above. In the
masses at League Hole there are signs of slipping, yet here also
there is sand overlying them, which I could not distinguish from
the adjacent Mid-Glacial sand.1 Along the beach, among the masses

Fig. 3.—Section in the little headland, near League Hole.
(Diagrammatic.)

Loam about 1% feet
i]

= ‘ =
., tance wast en)
DO SSR a Pos = oS ee oy
S = ttt .

ee Tate Weve See ee <A
Bememast ~ Pewee we ert tesa se HB ae

!
B.C. only just seen
under slip.

[ Looking west. ]
BC = Boulder Clay. S = Sand.

fallen from the cliff, pieces of Boulder Clay here and there occur,
where none can be seen on the cliff-top; these also probably have
come from the interior of the sands. The cliff is annually wasting,
so that the visible sections and their appearances are in a state of
constant change.

All the masses within consist of normal Chalky Boulder Clay
crowded with fragments of chalk. They all pass into the sands in
tongues, strings, or separate patches of a dark wet mud, like the
clay of the matrix, but containing no chalk. The mass nearest
Gorleston has many such streaks and patches, usually about 12 inches
by 2, in the underlying sand, to a depth of about 3 feet. Even
the mass first described, which, seen from the beach, seems to end
abruptly, on near inspection is found to have some of these patches
lying close to it in the sands. I do not see how these masses could
have been formed in situ. The appearances agree, however, in all
respects, with what would be expected if masses of Boulder Clay
surrounded by ice had been floated over the waters in which the
sands were being deposited, and had sunk where we find them. The

1 [For figs. 1, 2, and 3 my thanks are due to Prof. Bonney, who kindly
furnished them from his note-book. The sections at League Hole show that
the masses terminate in the interior of the cliff as well as in its face. ]

Vol. 52.] | REV. E. HILL ON TRANSPORTED BOULDER CLAY.

buoyancy of the ice would make the
masses at first practically weightless
in the water, so there would be
nothing to press down the floor on
which they sank. As the ice melted
away they would acquire weight,
but meanwhile deposition would be
going on all round. As the encom-
passing ice melted still further, por-
tions of the outside would break
away: hence the patches. Mud also
from the wet outside would ooze off
and spread on the sand floor, forming
the tongues and strings. In all
these the chalk would have dis-
appeared, as it has disappeared from
recomposed Boulder Clay, and gene-
rally from parts where water can
percolate. Meanwhile the progress
of deposition would have intermixed
sand with the patches, tongues, and
strings in undisturbed stratification.

The other group of transported
masses is different in character,
date, and locality. The group came
under my notice in my own parish
(Cockfield, Suffolk). Here is a series
of pits, containing a peculiar gravel,
which I have traced along a line of
about 7 miles, through the parishes
of Bradfield, Stanningfield, Cock-
field, and Lavenham. Their contents
resemble descriptions of ‘ Cannon-
shot Gravel’: they lie at correspond-
ing levels along the slope of an
existing valley, which is hollowed
out of Chalky Boulder Clay; and
they probably mark an earlier water-
course. They clearly indicate exten-
sive denudation of the Boulder Clay,
for the slopes of that formation rise
from 40 to 60 feet above them ; also
the flints which it contains are clean
of chalk, and have undergone con-
siderable wear. In two of these pits,
one near Cockfield ‘ Abbey’ and one
near Willow Bridge (the latter lately
filled in), masses of Boulder Clay are
found lying on the top of the gravel.

UOTYOOS JO JYSLOFT ‘HlOYNG ‘ppeyyooo ‘ospiag MOTI «vou pq]

["yooy g ynoqe

fejg sapjnog

Lo)
S
Est)
=
Dm
©
=)
o
Q
>
=
rst)
s
a

305

‘aanwb asunoo uo hurgsas ‘hnjo pas um hog wapynog yoyo fo seyong—F ‘Sti

306 REV. E. HILL ON TRANSPORTED BOULDER CLAY. [May 1806,.

In the Willow Bridge pit the clay was 2 or 3feet thick and extended
some 50 feet ; whether continuously or in several adjacent masses:
was uncertain : appearances were in favour of the latter view, but it
was difficult to decide on the nature of decomposed interruptions..
The outsides and the decomposed portions are a reddish clay or earth,.
but the cores are perfectly normal Chalky Boulder Clay, with much
chalk, in pieces from 2 or 3 inches long down to pea-size and grains.

It seems impossible to suppose that the agent which produced the
Chalky Boulder Clay, after ceasing to operate during the long
interval indicated by the gravels, again set up work and produced
these scanty fragments. The pits described lie on the side of
Boulder Clay slopes which rise, though gently, to considerably
greater heights. A natural explanation is that the masses have
come from higher ground, floated off or slipping down, in either case
probably in a frozen state. Between them and the gravel lie seams
of a finer clay, and over them something of the nature of brick-
earth ; while brick-earth is also abundant and worked at nearly the
same level midway between the two gravel-pits named. Under the
coarse gravel, in another of the pits, lie highly false-bedded white
gravel and sand. Thus there is abundant evidence of contemporary
water-action, and everything agrees with the view that these seams
of clay have been brought, not formed in satu.

If these conclusions are established, some consequences follow.
The writers in the Survey Memoirs on East Anglia frequently
mention beds of Boulder Clay in unusual positions, intercalated in,
or overlying, sands and gravels. May not many of these be also
transported sheets? If so, difficulties which the writers evidently
felt may be removed. Again, must not much caution be observed
in attributing an ‘interglacial’ age to beds, fossils, or implements
found beneath thin sheets of Boulder Clay, especially where this
occurs also at higher elevations in the neighbourhood ?

The Lowestoft instances would show that while in one locality
sands, called ‘ Mid-Glacial, were being deposited, in some other
locality the manufacture of true Chalky Boulder Clay had already
been commenced and perfected, so that exportation could goon. I
do not see that they give any evidence of the process of manufacture.
They are not unlike the pieces which might break off from the clay-
banks of a Siberian river :—but I must not wander far into the field

of conjecture.
Discussion.

Mr. H. B. Woopwarp suggested that in Mr. Hill’s Corton section
the Boulder Clay might occur in the form of an intrusive tongue ;
and in the West Suffolk section the isolated patches of Boulder Clay
might be remnants lying beneath a mass from which the chalky
portions had been removed by dissolution—a feature common in the
Eastern Counties.

Prof. Bonney said that he had carefully examined the section south
of Yarmouth with Mr. Hill, and could not find the slightest evidence
of intrusion of the Boulder Clay—a thing, by the way, of which he

Vol. 52.] REV. E, HILL ON TRANSPORTED BOULDER CLAY, 307

never could find evidence—but here the masses occasionally passed
in strings into the sand, and small boulders of clay occurred in the
sand below. Whatever might be the explanation, he could come to
no other conclusion than that the clay-masses were true boulders.

Dr. Du Ricue Pretter suggested, from the description given by
the Author, that the Boulder Clay wedged in between sand, as
shown in the first section, was probably deposited during an oscil-
lation of the drift-ice, the similar effect of such oscillations being
frequently apparent in the Alpine glacial deposits, which were, of
course, the product of land-ice. He had recently examined some of
the Boulder Clay of West Norfolk near Lynn, which was absolutely
different from the glacial clay of the Alps, and, in his opinion, was
clearly the product of drift-ice.

Mr. LamrtucH was reminded by the section on the wall of what
he had seen some years ago on the flank of the Muir glacier in
Alaska, where a strip of ice loaded with débris overran stratified
gravels without disturbing them. The presence of thin strips of
clayey material in gravels was a common phenomenon in Glacial
deposits, and he saw no difficulty in accounting for them as the
product of the edge of an ice-sheet. The admirable descriptions
given by the American geologists, especially by Messrs. I. C. Russell
. and T. C. Chamberlin, of the great glaciers of Alaska and Greenland
came as a revelation on many points to the students of glacial
geology, and deserved the closest study.

The AvurHor said that to suggest an ice-sheet as the cause of the
insignificant fragments of Boulder Clay upon the gravels was like
suggesting a steam-hammer as the cause where a few bits of
nutshell had been found.

Q.J.G.8. No. 206. y

308 PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,

17. OBseRvatiIons on the Grotoey of the Nit Vautey, and on the
EvipEncE of the GreaTER VotumeE of the River at a Former
Periop. By Prof. Epwarp Hutt, M.A., LL.D., F.R.S., F.G.S.
(Read February 26th, 1896.)

Parr I.

1. Introductory.

Tue evidence in favour of the view that the Nile was at one period
a river of vastly greater volume than at the present day is so
remarkable that it has forced itself on the attention of several
writers, amongst whom may be specially mentioned the late Prof.
Leith Adams,’ Prof. Zittel,? and Capt. Lyons*; and to the state-
ments coming from such competent observers I should hardly have
thought it necessary to add any of my own, were it not that I
find from personal intercourse that geographers have failed as yet
to grasp the full significance of the phenomena bearing on the
subject and described by the above-named authors. When about
to leave for a recent visit to the Nile Valley, I wrote to Prof. (now
Sir) Joseph Prestwich, enquiring whether he thought there were
any problems to which a travelling geologist might give attention
with some prospect of enlarging our knowledge of the physical
conditions of that remarkable line of country, and in reply he
recommended me to pay special attention to the terraces. This
advice I endeavoured to keep before my mind during my ascent
as far as the First Cataract and the return journey ; and I venture
to lay before the Society the impressions that I then received, and
the conclusions that I have drawn from them regarding the volume
and dimensions of the river at a prehistoric period. But, before
entering upon this special subject, I wish to note a few points con-
nected with the geological structure of the Nile Valley, which
came under my notice, although they may not be altogether new.

2. Some Points in the Geology of the Nile Valley.

And first let me observe that it is only by personal examination
that one can realize the extent of the erosion by old river-action
which was carried on after the Libyan region had been elevated out
of the waters of the sea at the close of the Eocene period. That
this erosion was accomplished mainly during the succeeding Miocene

1 Leith Adams, ‘On the Geology of a Portion of the Nile Valley, etc., with
Note on the Shells, by 8. P. Woodward,’ Quart. Journ. Geol. Soc. vol. xx.
(1864) p. 6. i

2 Zittel, ‘Beitrage zur Geologie und Palaontologie der Libyschen Wiiste,’
Paleontographica, vol. xxx. pt. i. 1883.

3 Lyons, ‘On the Stratigraphy and Physiography of the Libyan Desert of
Egypt,’ Quart. Journ. Geol. Soe. vol. 1. (1894) p. 531.

Vol. 52.] PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. 309

period, upon the rising of the land, there can be little doubt; as it
is becoming more clear that this was the special epoch of elevation,
disturbance of strata, and denudation over all the Egyptian and
Syrian region." But there was a second period of great fluviatile
inundation in what may be designated ‘the Pluvial period,’ ex-
tending from later Pliocene times into, and including, the Pleisto-
cene ; and to this latter stage I shall have occasion to recur later on.
At the present day erosion has almost ceased, and the fact that
the cultivated terraces bordering the river, as well as the plain
of Lower Egypt, are gradually rising with regard to the sea-level
by reason of deposition of sediment shows that the bed of the river
is also rising.” There is, therefore, no scouring action going on.

The fall of the river from Assuan to Cairo is a little over 6 inches
per mile, a fall just sufficient to keep the fertilizing sediment in
suspension when the river is not at its lowest. The magnificent
Nile Valley, of an average breadth of 10 miles, cut down through a
table-land of an average elevation of 800 to 1000 feet, capped by
Eocene limestone, and extending above Cairo for a distance of 300
miles, is a physical feature which must impress the observer with
the conviction of the enormous length of time during which the
Miocene erosion was in progress.”

The next point to which I wish to refer is the fact that in the Nile
we have a conspicuous example of a river running across escarpments.
‘Taking these in succession from the north up stream, they are :—
1, the escarpment of the Eocene limestone; 2, that of the Cre-
taceous limestone; 3, that of the Nubian Sandstone; and 4, in a
less degree, that of the granitic and schistose rocks of Assuan. The
dip of the strata towards the north, although generally almost
imperceptible, and sometimes reversed, is greater than the slope of
the river-channel. In consequence of this the transverse course
of the river was a physical necessity, if it was to enter the Medi-
terranean; but owing to the low angle of dip of the beds, and their
wide range, the fact is not so evident as it would be if the dip were
greater, and the range more contracted. Zittel has suggested that
the river once entered the Red Sea. This I cannot conceive to
have been possible at any point above Cairo, except during early
Pliocene times when Lower Egypt was submerged to a depth of
about 220 feet, and the waters of the Red Sea, united to those of
the Mediterranean, overflowed the entire region below this level.
In this sense the statement is true, but not otherwise. Asin the case
of the streams traversing the Chalk and Greensand escarpments in

' It is now becoming generally recognized that Miocene strata are absent
from the Egyptian area, which bears out the view above stated. See ‘The
Geology of Egypt,’ by Philip Lake, ‘Science Progress,’ vol. iv. (1896) p. 395;
also Prof. Mayer-Eymar, ‘Zur Geologie Aegyptens,’ Vierteljahrschr. Naturf,
Gesellsch. Ziirich, 1886.

? Otherwise the river would have ceased to reach the cultivated plain on its

nks.

3 From Zittel’s section across the Nile Valley it will be seen that the plateau
on the eastern side of the valley rises over 1500 feet in some places, and I am
inclined to think that the average height may be 1000 feet.

x2

310 PROF, E. HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,.

the Wealden area, once the course of the river had been selected as-
the land emerged from the ocean in Miocene times, that course was-
never abandoned. ‘The physical features of the region between the
Nile and the Red Sea are quite inconsistent with such an hypo-—
thesis as that referred to.

3. Faults.

Besides a depression along the general course of the Nile Valley
in the surface of the Eocene and Cretaceous beds, which must have
guided the original course of the river northward, faults appear to
have played an important part. ‘They have been noticed by Dawson,”
K. H. Johnson and H. D. Richmond,* Lyons,’ and others. That
which follows the line of the valley above Cairo has long been
known.

Another remarkable fault is shown on the right bank about:
5 miles below Farshit, following the course of the stream, with
the downthrow on the western side, along which the beds are —
highly tilted and bent. A third case at Gebel Ain, above Luxor,
is remarkable for the high angle at which the beds are seen to dip
(fig. 1). This is visible in the left bank of the river, and appears to:
follow its course in that locality.

Fig. 1.—Skeich at Gebel Ain, showing beds of limestone highly tilted
along line of fault.

[The escarpment of Eocene limestone is in the background to the right. ]

I refer to these cases merely in order to show that the line of
erosion of the primeval Nile was sometimes directed by the disloca-
tions of the strata; but some of the faults are transverse to those
which run parallel to the course of the stream, such as that at
Maghaghah.*

1 * Modern Science in Bible Lands,’ Appendix, 1888.
? Quart. Journ. Geol. Soc. vol. xlviii. (1892) p. 482.
> Ibid. vol. 1. (1894) p. 541. —

4 Described by Johnson and Richmond.

Vol. 52.] PROF. EH. HULL ON THE GEOLOGY OF THENILEVALLEY. 311

4. Relation of the Nubian Sandstone to the Granite and
Schist of Assudn.

The only other point bearing on the geology of the Nile Valley to
which I shall refer is the relation of the Nubian Sandstone to the
older rocks of Assuéin and the First Cataract. I should not have
thought it necessary to do so, had not some observers supposed
that the granite is intrusive into the newer formation. From an
examination of the junction at several places, I have satisfied myself
that there is no good warranty for this view. Undoubtedly the
original surface of the older rocks was very uneven, consisting of
ridges and furrows against, and upon, which the Sandstone Series
‘was deposited. But the latter is not in the least ‘baked’ or
*altered’ along the surface of contact, while the local basement-
beds are often conglomeratic, pebbles of quartz, probably derived
from the granite itself, being abundant. The junction is remarkably
well shown above the ancient quarries, along the pathway leading
to the barracks which overlook the Nile Valley, and the accom-
panying sketch was taken on the spot.

Fig. 2.—Sketch of junction of granite and Nubian Sandstone near
the Barracks, south of Assudn.

Se
' one ke: 3
oe I a St
ay, ~— ° A) 0 er Bee ere ake he
Z % ty = a ° Mite fe s
‘a : — aS boty
Ger! G A SON AG,
: oe, if y ait 4; RWS aL NS hy
(ps ay Bg NS RAEI a
“if : P feae G NB G
1=Coarse brown grit. G=Granite, weathering into rounded
2=Grey and purple sandy shale masses.

(10 feet).
3=White freestone, coarse to fine, B=Basalt-dyke, 8-10 feet wide.
with quartz-pebbles.

The general structure of the locality is illustrated in the above
section, taken from the banks of the river opposite the Island of
Sehél, about 3 miles south of Assudn.

5. Age of the Nubian Sandstone.

I shall not enter here on the question whether the whole of the
Nubian Sandstone of the Nile Valley is of Cretaceous age, or
whether it is partly Carboniferous. It is a problem which can
be solved only by a careful survey of the whole region, which, as
announced, is to be immediately undertaken by the Egyptian
Government, under the direction of Capt. Lyons. I will only
observe that some portions of the formation which I was able to
examine in the Nile Valley are very unlike in mineral composition

312 PROF. E, HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,

to the Nubian Sandstone of Cretaceous age in Arabia Petra and
the Arabah Valley. This, however, is not surprising, considering
the distance by which the two localities are separated, and does not
afford any evidence that the formations are of different geological
ages. In Arabia Petrea and along the eastern side of the Wadi-
el-Arabah, the Nubian Sandstone is distinguished by rich red and.
purple or yellow colouring; the base is a conglomerate where it
rests upon the crystalline rocks, and bands of clay or marl are rare."
On the other hand, as Lyons has shown, bands of clay are common
in the Nubian Sandstone of Upper Egypt,’ while the prevailing tint
is light grey or brown, sometimes slightly tinged with red or pink.
It is this stone which was so largely used in the building of the
temples, and which has wonderfully resisted the effects of time.

Part II.
6. The Levels of the Ancient Nile.

The evidence upon which the former greater volume of the Nile
waters is inferred may be considered under two heads: (1) the river-
terraces now beyond the reach of the highest floods, and (2) the
old river-channels through which the waters cannot now pass,
owing to difference of level. We shall consider these separately.

(1) The Rwer-terraces.—In order to arrive at a clear knowledge
of the bearing of this subject upon the question of the former
volume of the Nile, it may be observed that the general structure
of the valley as far as the First Cataract is, on the whole, remark-
ably uniform and simple. First, we have the valley itself shut in
on either hand by the escarpments along which the plateaux of the
Libyan and Eastern’ deserts terminate; then, from the base of
these escarpments there extends, on one or both sides, a slightly
sloping terrace, formed of alluvial gravel, sand, or mud, of varying:
breadth, and terminating along a well-defined bank rising above a
lower terrace which, in-turn, breaks off along the banks of the river.
This lower terrace (No. 1) consists of Nile mud, is richly culti-
vated or planted with palms or other trees, and is watered by the
Nile inundations. The terrace above (No. 2) is absolutely destitute
of vegetation, and its surface, formed of yellowish gravel or sand,.
contrasts in a striking manner with that of the lower terrace
above which it rises. Other terraces at higher levels there may be
in Middle Egypt, connected with the epoch of Pliocene submer-
gence,’ of which I shall have to speak presently; but the above

1 «Geology of Arabia Petrza,’ Mem. Palest. Explor. Fund (1886), p. 54.

2 Quart. Journ. Geol. Soc. vol. 1. (1894) p. 533.

3 Generally called in the maps ‘the Arabian Desert,’ because largely in-
habited by Arabs, but the name is misleading.

4 Or during the emergence of the Miocene period, and represented by the
caves and terraces at levels of about 500 feet described by Sir J. W. Dawson,
‘Modern Science in Bible Lands,’ Appendix, 1888, p. 541; and Geol. Mag.
1884, pp. 289-92.

Vol. 52.] PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. 313

description applies, with slight modification, to the whole valley as
far as Assuan, and also between this and the Second Cataract,
as may be gathered from the descriptions of Prof. Leith Adams and
Capt. Lyons. The following section, taken across the valley at
Farshit, is intended to show its general structure :—

Fig. 3.—Section at Farshit.

Terrace 1.—Liable to floods. Cultivated.
Terrace 2.—Older. Beyond the reach of floods.
Terrace 3.—Plateau of Hocene limestone at the border of the Desert.

That terrace No. 2 was originally the bed of the Nile there cannot
be a doubt, and the occurrence of fluviatile shells in the strata
is not required to strengthen this view. These were found by
Leith Adams both above and below the First Cataract. Where
I examined the beds, at Thebes and Assuan, I was not so fortunate
as to find them. I will now mention a few localities where terrace
No. 2 may be observed above Girgeh.

(a) Girgeh.—Where the valley widens a short distance above
Girgeh, terrace No. 2 is distinctly seen, rising, say, about 80 to 100
feet above the cultivated terrace (No. 1). The level is rather
higher than that farther up the valley. This may be accounted for
by the Pliocene submergence, which would have affected the level
of the river nearly as far as Girgeh; to this I shall again have to
refer.”

(6) Above Kasr-es-Sayad the western escarpment of the Eocene
limestone recedes for a great distance from the river-side, and here

1 Dawson believes that the sea-waters reached as far as the First Cataract,
supposing the 500-foot caves and terrace above the Nile at Gebel Mokattam to
be due to submergence, which is uncertain in the absence of marine forms at
this level. But the only certain raised sea-beach—that discovered by Prof. Fraas
—is nearly 300 feet lower, and the sea-waters in this would not have reached
farther than Girgeh, as above stated.

[For this determination I am indebted to Mr. Garstin, Chief of the Egyptian
Public Works Department, who kindly sent me the following statement while
this paper was passing through the press :—

‘Distance from Cairo in kilometres at which the high-water level was
220 feet over the sea :

1890=562 kilometres from Cairo.
1891=563 Pe f
1892=558 is eS
1893=566 a i
1894=560 x s
1895=564 - “

‘The mean is 563 kilometres from Cairo,’ or 339°57 miles. This distance
would reach to within 2 miles of Girgeh, which is 3414 miles from Cairo.—
April 25th, 1896.]

314 PROF. E, HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,

both the cultivated plain and terrace No. 2 extend over very large
areas. The latter is very distinct, rising in a bare yellowish slope
of 40 to 50 feet (estimated) above terrace No. 1, and stretching to
the flanks of the valley.

(c) On the right bank of the Nile at El Kab, about 15 miles
south of Esneh, both terraces are clearly defined. Here a village of
mud-huts is built upon terrace No. 2, below which is the cultivated
flat, and behind rises a fine cliff of Cretaceous limestone.

(d) The sloping plain on which was built the city of Thebes
is referable to the second terrace. It consists of beds of sand and
gravel, laid open near the temple of Medinet Abu, bounded inwards
by the grand semicircular escarpment of the Eocene beds, and
towards the river by the wide plain, richly cultivated and abun-
dantly watered at Nile flood. From this plain rise in solitary
grandeur the Colossi of Memnon,' and as it is improbable that they

were originally (over 3300 years ago) erected on a basis liable to

the floods of the Nile, we have here evidence that the bed of the
river and the plains on its banks have been raised by repeated de-
positions of sediment ;—an inference borne out by other examples
of a similar kind. Terrace No. 2 forms a wide plain west of Thebes,
but it becomes very narrow at Kurnah in the opposite direction.
From this neighbourhood, at El Waddi, Gen. Pitt-Rivers obtained
some flint-flakes supposed to be of human workmanship, embedded
in banks of undisturbed gravel.’

_ (e) Opposite Kém Ombo, on the western bank of the river, the
floor of fhe old Nile is laid open on the banks of the river itself,
and is peculiarly interesting, as it is composed of laminated brownish
mud lying at the foot of a range of sandhills, and rising from 30 to
50 feet above the margin of high Nile. I give here a sketch of this
interesting section, which was pointed out to me by Capt. Lyons.

Fig. 4.—Terrace of Old Nile mud near Kém Ombo.

1=Low terrace of clay, covered with vegetation.
2—Old terrace of Nile mud, laminated : 30 to 40 feet above the highest floods.
38= Bank of sandhills. Nile in foreground.

1 1500 z.c. according to Dr. Budge, ‘The Nile, 3rd ed. p. 18; 1400 B.c.
according to Prof. Rawlinson, ‘ Ancient History,’ p. 39.

2 Journ. Anthrop. Inst. , May 1882; quoted by Prestwich, ‘ Geology,’ vol. ii.

. 483. Dawson, however, doubts that these were the work of man (‘ Modern
Science in Bible Lands, Appendix, 1888, p. 541).

a

Vol. 52.| PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. 315

In some places, between Silsileh and Assudn, the second terrace
seems to merge at the surface into the low terraces of the Nubian
Sandstone, the grand escarpment of the Eocene limestone having
given place to the Nubian Sandstone. In this district Leith Adams
discovered numerous river-shells at a level of at least 120 feet
above the highest Nile of the present day.’

(f) Old terraces above the First Cataract.—According to Leith
Adams, the old terraces now rising far above the highest floods of
the Nile at the present day may be traced at intervals along the
valley between the First and Second Cataracts. One of the most
remarkable instances occurs at Derr, the capital of Nubia, about
80 miles below the Second Cataract. Here, above the cultivated
terrace liable to floods, rises a cliff of sandstone, above which is a
second sloping terrace, rising from 110 to 130 feet above highest
Nile, formed of pebbles, among which Adams found numerous
specimens of Cyrena fluminalis, a shell now abundant in the Nile
waters. Some miles farther northward, in the same terrace, the
same shell was found in reddish sandy soil, together with Bulimus
pullus. Similar terraces were recognized at Gharbea, north of
Korosko, at Dakke and Gertassee, rising from 60 to about 100 feet
above the highest Nile floods, and containing several species of fresh-
water mollusca.” These observations are confirmed by Capt. Lyons,
who speaks of the large sheets of gravel, which in Nubia extend
for a length of 7 or 8 miles along the Nile bank at Debera, 8 miles
north of Wadi Halfa, at 100 feet above the present Nile floods, and
containing shells, such as 4theria semilunata, Cyrena fluminalis,
Unio, and Paludina.’

(g) But these evidences of former higher levels do not cease at
the Second Cataract, for Capt. Lyons has shown,* by the position and
inscriptions on the rocks and temples dating as far back as 2200 B.c.,
that the river then rose to a maximum of 27 feet above its present
flood-level ; the amount of rise decreasing as time went on. Lyons
suggests that these variations of the river were caused by earth-
movements; but it seems more probable that they are referable to
the same general causes as those which have given rise to the high
terraces occurring at intervals down the valley into Lower Egypt.

Thus we have seen that, throughout a distance of between 600
and 700 miles above Cairo, the evidence derived from the terraces
is cumulative, and tends to prove that the original surface of the
Nile waters stood at a level varying from 50 to 100 feet or more
above that of the present day.

Part ITI.
7. Old River-Channels.

How many channels of the primeval Nile there may be which
the river has deserted in consequence of the fall of its surface I

1 Quart. Journ. Geol. Soc. vol. xx. (1864) p. 9. 2 Ibid. pp. 13, 14.
8 Ibid. vol. 1. (1894) p. 543. 4 Ibid. p. 544.

316 PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,

am unable to state, but we are happily in possession of exact in-
formation regarding two of them: one at Kém Ombo, about 26
miles below Assuan, and one at this latter place itself. Of these I
now proceed to give some detail.

(1) Kom Ombo (or Kom Ombos).—The remarkable ruins of two
temples perched on a cliff overhanging the river, which is con-
stantly being undermined, and is threatened with eventual de-
struction, derive much interest from the fact that they are built
on the alluvia of the old Nile, and formed part of its ancient bed
before the waters had fallen away to their present level. The
surface of the highest Nile-floods does not reach to within more
than 12 metres (39°38 feet) of this old terrace, as stated by Mr. W-
Willcocks, of the Egyptian Public Works Department,! and both he
and Leith Adams discovered shells of the genera Cyrena (Corbicula),
Unio, and Paludina in the alluvial beds at a level of 11 metres.
(36°08 feet) above present highest floods. In order to compare the
relative levels of the floods of the present day with those of the
ancient river at this place, we ought to add about 30 feet to that
of the floor, which will show a difference of about 70 feet for the
respective surfaces.

(2) Assuan, which is built on the cultivated terrace at the
northern or lower end of the First Cataract, is connected with
-Shellal at the southern or upper end, not only by the river, but by
two valleys, one or both of which were probably river-channels
when the river flowed at a higher level. They le parallel to each
other and to the Nile itself on its eastern side.” Of one of these
only can I speak with certainty, time not having allowed me to
make a proper examination of the other. Along this, the more
easterly of the two valleys, the railway connecting Assuan and
Shellal is carried for a distance of about 7 miles. It is about
half-a-mile wide, running between rugged slopes of granite capped
by horizontal courses of Nubian Sandstone. The floor of the valley
is even, affording camping-ground for a tribe of Bedawin Arabs,
and is composed of sand, gravel, and mud rudely stratified. The
surface rises to a low saddle about 2 miles south of Shellal, the
height of which has been kindly determined for me by Capt. Lyons.
by levelling to be 83:41 feet (28-48 metres) above highest floods:
at Shellal and the island of Phil, which is opposite this village; and.
here, again, if we wish to compare the original height of the water-
surface with that of the present day, we may add, as a safe estimate,.
25 or 30 feet— making 108-41 feet as the amount of difference of
surface during high floods. This level exceeds that at Kom Ombo,.
but may be accounted for by the difference in the physical con-
ditions of each place; the Nile being here narrowed and encumbered

1 Report to the Government of Egypt on ‘ Perennial Irrigation, etc.,’ 1894.
Appendix vii. p. 13. Willcocks has also noticed Atheria nilotica in the old
Nile deposits both above and below Gebel Silsileh, 2bid. p. 14.

* Baedeker’s ‘Guide to Upper Egypt’ contains an excellent little map of
the environs of Assuan (ed. 1892, p. 274).

3 My first visit to this valley was in company with Capt. Lyons, who indi-

cated its origin as an old Nile valley, a view which a subsequent visit fully
confirmed.

Vol. 52.] PROF, E. HULL ON THE GEOLOGY OF THE NILEVALLEY. 317

by granite ridges, instead of having merely to find its way
through a wide plain as at the latter place. Near the northern
end of the railway-cutting above Assuén we find a deposit of the
old Nile mud with bands of pebbles resting on the upturned edges
of the ancient schists.

Fig. 5.—Section from the river-bank opposite the Island of
Schél at the First Cataract.’

E.
W. S Ss S
d ae Old Nile
R. Nile wets Channel
19 2X
eae A

S =Nubian Sandstone and Conglomerate.
G=Granite forming the sides of the present and ancient channels of the Nile.
[Distance = over 2 miles. |

The valley now described was recognized by Leith Adams as an
ancient river-channel, and in the alluvial deposits in the ravines
north of it he was fortunate in discovering numerous shells, such as
Aitheria semilunata, Iridina nilotica, and Bulimus pullus.” Time
did not permit of a careful search on my own part.

From the foregoing facts and considerations it will be observed
that the evidence of a former higher Nile surface afforded by the old
terraces is confirmed by that of the old channels. The waters
which formerly extended over the floor of the Nile Valley with a
breadth of several miles are now confined by banks which are
seldom 4 mile apart, and this has resulted, not in consequence
of the deepening of the channel, but by reason of the diminution
in volume of the waters themselves. This is shown by the fact
that there is no scouring of the Nile channel, the current being
insufficient for this purpose; and besides this, the borings which
have been made show that the bed of the river is composed of
alluvial mud of considerable depth.* The bed is, in fact, rising by
accessions of deposit comparable with that which is annually spread
over the cultivated lands on either side during the high floods, and
which has been estimated by Mr. Willcocks, Engineer to the
Public Works Department, to amount to 0-12 metre (4:7 inches)
in 100 years. We are therefore obliged to have recourse to
another explanation—namely, the decrease, and in part cessation,
of the rainfall over the entire hydrographical basin of the river—
in order to account for the decrease in volume.

The hypothesis of a former greater volume of the river has the
support of Leith Adams, Zittel, Lyons, and others, and may there-
fore be considered as an accepted hypothesis: though it is not, as it
seems to me, brought forward with sufficient prominence by writers

* It is near this place that the great Nile embankment is to be made.

? Quart. Journ. Geol. Soe. vol. xx. (1864) p.15. The species were determined
by the late S. P. Woodward, of the Natural History Museum.

3 At Silsileh, where the Nubian Sandstone crosses the river, the solid rock
was still not met with after boring to a depth of 20 to 25 metres (65 to 73 feet)

below low Nile, ‘ Rep. Technical Commission,’ p. 21 (1894).
4 Report on ‘ Perennial Irrigation of Egypt,’ 1894, p. 12.

318 PROF. E, HULL ON THE GEOLOGY OF THE NILE VALLEY. [May 1896,

on Egyptian geography, who have had generally other objects of
investigation before their minds, but I should like to quote in this
connexion the language of Prof. Zittel as follows :—

‘Alle diese Thatsachen beweisen, dass der Nil einst ein weit
michtigerer und reissenderer Strom als heutzutage war, und dass
die Gattung theria, welche jetzt erst stidlich von Assuan beginnt,
fruher weiter nach Norden verbreitet war.’ *

Part IV.
8. The Pluvial Period.

When traversing, in 1883-84, the fine valleys of the Sinaitic
Peninsula and Arabia Petrea, the bottoms of which, now dry, are
composed of alluvial deposits, I came to the conclusion that at a
former period, and under different climatic conditions, they con-
stituted the channels of an extensive river-system draining into the
Red Sea.” It is only at rare intervals that rain falls over this
region, in the form of spasmodic thunderstorms of short duration,
and they are quite insufficient to account for the formation of valleys,
sometimes a mile or more in breadth and hundreds of feet in depth,
The dry river-valleys which open into the Nile, chiefly along the
eastern side, tell a similar tale. The streams which flowed along
them, and by which they were excavated, have dried up and
disappeared. The period during which this process of valley-
erosion, of terrace-formation, and of high floods went on may well be
designated ‘ Pluvial’—extending from the Pliocene down through
the post-Pliocene, and terminating with recent times. It is a term
indicative of meteorological rather than geological conditions, though
not unconnected with these.

ConcLuUsION.

The conclusion to which we are driven from a consideration of
the above phenomena is that the Nile has decreased in volume to
a large extent, as compared with that of primeval times. It only
remains to consider how and when this decrease has arisen.

(1) As regards the manner in which this change took place,
there can be only one answer: by the drying up of its sources and
tributaries owing to decrease in the rainfall. Throughout 1200 miles
of its course, the river runs through a region well-nigh rainless,
where its waters are subject to a constant drain through evaporation ;
in consequence of which its volume at Khartum is considerably
larger than it is at Cairo; and the only wonder is, when one con-
templates the extent of this evaporation, especially during the

2 «Paleontographica,’ vol. xxx. (1883) p. 137. Zittel founds this opinion
mainly on the discoveries by Leith Adams of fluviatile shells in the terraces
beyond the reach of the highest floods.

2 «Geology of Arabia Petrza, etc.,’ Mem. Palest. Expl. Fund, passim.

3 Such as the Wadi Sonnur, opposite Beni Suef; W. Tarfeh, north of
Minieh ; W. Siut, opposite the town of the same name; W. Gassab, opposite
Girgeh ; W. Keneh, a valley with numerous branches, opposite Keneh; and
‘W. Abu Wassel, below Luxor.

Vol. 52.| PROF. E. HULL ON THE GEOLOGY OF THE NILE VALLEY. 319

hotter months, that its waters ever reach the Mediterranean at all.
That they do so is owing to the fact that it is during these months
that the waters rise by reason of the Abyssinian floods. The
numerous dry valleys which enter the Nile Valley in Middle and
Upper Egypt and Nubia show that this region was once abundantly
watered.

When we consider the enormous ‘area of the hydrographical basin
of the Nile, estimated at 1,100,000 square miles, we can under-
stand how a slight climatic change in the direction of increased
humidity and decreased temperature would cause an enormous
expansion of volume of Egypt’s great river. This is really what I
believe took place; and it now remains to consider the period to
which we should refer these altered conditions.

(2) During the Miocene period, when the primeval river was
channelling out its bed, and when the land was relatively higher
than at present as regards the surface of the Mediterranean, the
climatic conditions may haye been altogether different from those
of the present day over the Nile Basin ; but whether this was the
case or not, we have good grounds for believing that during the
subsequent Pliocene period, when Lower Egypt was submerged to a
depth of over 200 feet, and the sea stretched up the Nile Valley for
several hundred miles, the conditions were different from those of
the present time. The increase of water-surface must have been
accompanied by increased humidity, and a lowering of tempera-
ture, compared with that of Miocene times. And when these
Pliocene conditions gave place to those of the Pleistocene period
the climatic conditions in the same direction must have been still
further advanced. The lowering of temperature over all the
Europasian regions to the north must have greatly affected those
we are now discussing. To what extent the annual mean tempe-
rature of the subtropical regions of Africa was lowered during the
Glacial period of the temperate zone can scarcely be estimated with
precision, but that the general effect was brought about cannot, as
it seems to me, be contested. My own view is that in these
regions the climatic conditions were similar to those of Europe at
the present day, both as regards temperature and rainfall; and if
such were even approximately the case, it is easy to account for the
vastly greater volume of the Nile waters as compared with those
which render Egypt not only a habitable but a fertile country.
For this epoch I adopt the term first, I believe, suggested by
Mr. Jameson for this part of the world—namely, the Pluvial
period.’

* Lyons considers that at this period (post-Pliocene) there was ‘a con-
siderable rainfall’ over the area of the Libyan Desert, though not excessive.
Quart. Journ. Geol. Soc, vol. 1. (1894) p. 542. See also EH. A. Floyer, ibid.
vol. xlviii. (1892) p. 580.

? Capt. Lyons has unintentionally misrepresented my meaning when he
suggests that I have restricted the term ‘ Pluvial period’ to that represented
by the Glacial of Europe. On the contrary, I expressly regard it as extending
from the Pliocene down to the close of the post-Pliocene, as will be seen on
referring to my memoir on the ‘ Physical Geology of Arabia Petrea and
Palestine,’ Mem. Palest, Explor, Fund (1886), pp. 69, 113.

320 GRANOPHYRES OF STRATH (SKYE). [May 1896.

18. On ceRTAIN GRANOPHYRES, MODIFIED by the IncorPoRATION of
GaBBro-FRaements, 7 SrratH (Skye). By Atrrep HarKer,
Ksq., M.A., F.G.S., Fellow of St. John’s College, Cambridge.
(Communicated by permission of the Director-General of the
Geological Survey. Read February 26th, 1896.)

[Puates XIII. & XIV.]

Tue district of Strath in Skye, which has so often formed the
subject of geological description, has been assigned to me to be
mapped in detail for the Geological Survey ; and while engaged in
this duty, during the past summer and a portion of the autumn, I
had occasion to study the complex series of eruptive rocks which
extends from Loch Slapin on the west to the Sound of Scalpay and
Broadford Bay on the east. Among the features of interest con-
nected with these igneous rocks, special importance attaches to
their relations one to another, and this subject has received due
attention. The full details will be fitly deferred until the appear-
ance of the official Memoirs; but, with the sanction of the
Director-General, I now present to the Society the following brief
account of certain minor intrusions of granophyre illustrating a
peculiarity which, I believe, has not yet received notice.

The granophyres of Skye have been described, as a whole, by
Macculloch, Oeynhausen and von Dechen, J. D. Forbes, Sir Archi-
bald Geikie,! Prof. Zirkel, and Prof. Judd. Despite mineralogical
and textural variations, these rocks have a general community of
characters, which they share also with rocks of various ages in
other regions. ‘The examples to be described, however, present
quite exceptional features, which seem to be worthy of examination.
They form five distinct intrusions lying north and west of Loch
Kilchrist and 2 or 3 miles south-west of Broadford (see Map).
At this locality occurs a large tract of massive volcanic agglomerate,
which has its own interest as marking, according to Sir A. Geikie,?
the site of a large volcanic vent. It is within, and on the borders
of, this agglomerate-tract that the intrusions are situated. In the
surrounding district numerous other masses of granophyre occur.
Immediately to the north is the large boss forming the Red Hills ;
to the south is another rising into Beinn-an-Dubhaich, while
several smaller intrusions are perhaps to be regarded as offshoots
from these large ones; but from all of these the peculiar rocks in
question are at once picked out in the field as presenting marked
differences from them.

1 T follow Sir A. Geikie in grouping all the Tertiary acid rocks of this region
under the collective name ‘ granophyre,’ which is strictly applicable to most of
them, although there are transitions both to the granitoid type on the one hand
and to fine-textured ‘ quartz-felsites’ on the other.

2 Trans. Roy. Soc. Edinb. vol. xxxv. (1888) pp. 107-109.

EXPLANATION. GEOLOGICAL SKETCH-MAP
Paeals Aesionaa OF PART OF
olcanic Agglomerate : \
including some large ei- ~ i S TR A ih H (Ss K ag E >;
closed patches of tava 197 3 hea! by Alfred Harker / 7S!
Granophyre. G M.A, F.G.S. 14 Vv
pene Granophyre with we y} d, 7/ H’
4 Gabbro-fragments. E D
Scale: 3 inches=7 mile. Age
x S ApELP AT ZI I mee
aN yy AN OP/H/Y om

322 MR. ALFRED HARKER ON THE [May 1896,

Compared with what may be called the normal granophyres of
the district, these rocks are darker and manifestly richer in the
iron-bearing minerals. Examination shows, too, that they are
decidedly denser: ten specimens gave specific gravities ranging
from 2°56 to 2°73, with a mean of 2°66, while twenty specimens of
the normal granophyres of the district gave from 2°51 to 2°66, with
a mean of 2°58. Closer inspection often reveals a mottled appear-
ance, due to the dark minerals tending to cluster in vaguely defined
patches, and in places these patches become more distinct and are
seen to represent enclosed fragments of some basic rock. In other
respects, for example, in the prevalence of the micrographic structure,.
in the drusy character of the more coarsely textured type, etc., these
rocks show a close correspondence with the normal granophyres of
the district. It cannot, of course, be asserted that they agreed
precisely with the latter as regards the composition of the original
magma, but it will be shown that the differences which now exist
are certainly due, at least in the main, to the taking up and partial
dissolution by the acid magma of foreign rock-fragments of more
basic composition.

It is to be observed that these peculiar granophyres do not occur
as marginal modifications of, or as having any visible relation to,
granophyres of the normal kind, but as independent intrusions.
Moreover, the special characters of these rocks are distributed with
considerable uniformity throughout each intrusion. Another point
to be noticed is that the enclosed rock-fragments have not been
derived from the rocks which border the intrusions as seen in out-
crop. Excepting that the most easterly and the most westerly of
the intrusions are in part bounded by limestone, the rock in contact
is everywhere the volcanic agglomerate. The rock-fragments in
the agglomerate are chiefly of sandstone and grit, probably Jurassic,
and basalt similar to that of the bedded lavas of the district. The
included fragments in the granophyre are in general of gabbro,
which I have not detected in the agglomerate. They were there-
fore derived from some subterranean source, and, as we have seen,
from such a depth as to allow of their becoming distributed with
some regularity through the involving magma prior to the con-
solidation of the latter in its present surroundings.

The literature of foreign fragments enclosed in igneous rocks is
voluminous, but it gives little information bearing on such a case
as the present, where portions of a basic rock have been enveloped
and attacked by an acid magma. Indeed, Zirkel* remarks that
‘ caustic’ action is not known in the case of fragments enclosed in
granites and syenites. The fullest account of such phenomena is
that given by Prof. Sollas* in his description of the relations of
the granite and gabbro of Barnavave in the district of Carlingford.
This occurrence has obvious points in common with the one under
discussion: some of the differences between the two will be brought
out in the following pages. The modifications exhibited by the

1 «Lehrbuch der Petrographie,’ 2nd ed. vol. 1. (1893) p. 598.
2 Trans, Roy. Irish Acad. vol. xxx. pt. xii. (1894) pp. 477-512.

Vol. 52. | GRANOPHYRES OF STRATH (SKYE). 323

Carrock Fell granophyre near its contact with a highly basic gabbro
have been described by the present writer,! but there the disso-
lution of the derived material has been much more complete, and
the analogy with the present case is more remote.

The xenoliths* in our granophyres are, as a rule, less than an
inch in diameter, and have ill-defined outlines. Those readily
recognized and identified by the eye as distinct foreign fragments
are not common. In the thin slices undestroyed xenoliths are not
frequent (6704), but altered xenocrysts are universally found.

Most of this derived material has undoubtedly come from a
gabbro, and from one closely comparable with the ordinary gabbros
of the district, such as that which occupies a considerable tract to
the north-east of the Red Hills. Of these gabbros, as seen in situ,
a summary description will suffice. They consist essentially of
felspar and augite. The felspar is usually a labradorite, often in
idiomorphic crystals showing some zonary banding between crossed
nicols. ‘The augite is pale brown to almost colourless in thin slices.
Instead of the true diallage-structure, parallel to the orthopinacoid,
it has usually a delicate striation * parallel to the basal plane, often
emphasized by a more or less pronounced schiller-structure. This
frequently affects only part of a crystal, and it imparts a deeper
brown tint to the slice. A rhombic pyroxene is rarely met with in
the gabbros of this district, though it occurs in some of the coarser
rocks of the Cuillin Hills, farther west. Recognizable olivine is
not common, although it may sometimes be concealed by secondary
magnetite-dust, as remarked by Prof. Judd. Original magnetite
often occurs, in shapeless grains or patches. Needles of apatite
are met with, but by no means constantly.

The gabbro-débris in the granophyre is seen in the thin slices in
different stages of dissolution, but is for the most part completely
disintegrated by the caustic or solvent action of the acid magma on
some of its minerals. Those constituents which resisted such action
have been set free, and now figure as xenocrysts, either intact or
more or less perfectly transformed into other substances. At the
same time the material absorbed has modified the composition of
the magma, in the general sense of rendering it less acid, and this.
is of course expressed in the products of the final consolidation of
the granophyre. In order to present in systematic form the obsery-
ations made, it will be convenient to begin by enquiring what has.
befallen each of the chief constituents of the gabbro.

1 Quart. Journ. Geol. Soe. vol. li. (1895) pp. 125-139.

2 [Kor conyenience, I adopt Prof. Sollas’s terms, ‘xenolith’ for an enclosed
foreign rock-fragment, and ‘xenocryst’ for an isolated crystal of foreign
derivation. |

3 [I follow Mr. Teall (Quart. Journ. Geol. Soc. vol. xl. 1884, pp. 646, 647).
in terming this structure simply a ‘striation.’ It does not appear to be a twin-
lamellation, and I have not been able to satisfy myself as to its true nature.
Mr. Teall regarded it, in the Whin Sill, as of secondary origin; but I have
seen nothing leading to this conclusion in the gabbros of Skye, of Carrock Fell,
of St. David’s, etc., and its occurrence in ‘xenocrysts’ as detailed below would
be difficult to reconcile with such a supposition.—March 12th, 1896. |

@o5, GS. No. 206. Z

324 MR. ALFRED HARKER ON THE [May 1896,

It is probable that the needles of apatite seen in most of the
slices have been in part derived intact from destroyed gabbro-frag-
ments, but this is not susceptible of decisive proof. Similar needles
occur in the normal granophyres as well as in the gabbros of the
district, and their rather capricious distribution in both rocks
renders unsafe any argument founded on the relative amounts of
the mineral in different. slides.

It is the augite that affords the most conclusive proof of the
extraneous origin of the xenocrysts, and this is due to the charac-
teristic basal striation of the gabbro-augite, a feature not found in
the augite of the normal granophyres. In the recognizable enclosed
fragments of gabbro (6704)? the augite shows no change except a
conversion to brownish-green, rather fibrous hornblende at the edge
of the crystal, a transformation very common in the ordinary gabbros
of the district (Pl. XIII. fig. 1). In the isolated xenocrysts the
conversion to hornblende is usually far advanced, and in these rocks
in general this mineral predominates over augite. It is yellowish to
brownish-green or sometimes greenish-brown in colour, and of com-
pact (as contrasted with fibrous) structure. Very often there is a core
of unchanged augite with the basal striation that indicates its deriva-
tion from gabbro, and the traces of this structure are sometimes seen—
even when the conversion to hornblende has been complete (Pl. XIII.
fig.3). Failing this evidence, the derivation of the hornblende can
often be inferred from the irregular shape of its crystals, or from its
enclosing abundant shapeless grains of magnetite. On the other
hand, there is usually some hernhlende presenting the crystal outlines
proper to that mineral, and this must certainly have crystallized out
from the modified granophyre-magma (PI. XIII. figs. 4.5). In some
slides it is very plentiful. It does not differ materially in colour and
pleochroism from the pseudomorphic hornblende. It may be re-
marked that when the latter encloses a core of unchanged augite the
two minerals have the usual crystallographic relation, the 6 and ¢ axes
being common to both: in a clinopinacoidal section the extinction-
angle of the augite is 39°, and of the hornblende 18°, on the same
side of the vertical (2674). In addition to the augite plainly derived
from gabbro, several of the slides contain rather rounded grains of
augite showing neither basal striation nor partial conversion to horn-
blende. Unless these be relics of vanished xenoliths of basalt, they
are probably to be regarded as having crystallized out directly from
the modified granophyre-magma (Pl. XIII. fig.1). This would not
be remarkable, for augite is widely distributed in the normal grano-
phyres of the district, where it often occurs side by side with original
hornblende, Since, however, non-striated augite is found in many

of the gabbros, the absence of this structure cannot in itself be
regarded as conclusive.

At Barnavave the xenocrysts of diallage are described by Prof.
Sollas as showing three different lines of alteration, the characteristic
products being respectively granular augite, biotite, and green horn-

1 The numbers between parentheses are those of the slides in the collections
of the Geological Survey.

Molge GRANOPHYRES OF STRATH (SKYE). 325

blende, with magnetite as a concomitant of each. Only the last of

these three is clearly represented in the present case ; newly-formed
augite has been produced only indirectly by later secretion from the

modified magma, and biotite has not been observed. At Carrock
Fell the derived augite-crystals have been completely absorbed by

the magma, and subsequent crystallization has given rise to new

augite with hornblende and biotite.

Two of the slides (2674, 6703) afford evidence of the occurrence of
xenocrysts of enstatite and hypersthene. There is a partial conver-
sion to hornblende at the margin, while the interior is serpentinized
or more rarely unaltered (Pl. XIV. fig. 7).

Occasionally pseudomorphs after olivine, apparently of ‘ pilitic’
amphibole, are seen enclosed in the relics of striated augite (6704),
or isolated in the granophyre-matrix (6703). There is no decisive

criterion to determine whether these latter have come from the

gabbro or from destroyed basalt.

Magnetite-grains of irregular shape are embedded in many of the
augite-xenocrysts and the hornblende-pseudomorphs after them,
and these do not differ from the grains in the original gabbro.
Most of the abundant magnetite in the slices is, however, of a
different kind, building perfect or imperfect octahedra. Though
partly representing in substance iron ore absorbed from gabbro-

débris, it is evidently a new crystallization from the modified

granophyre-magma. At Carrock Fell the iron ore from the gabbro
has been mostly, but not entirely absorbed ; its partial survival may
be due to its extraordinary amount and its highly titaniferous
nature.

Distinct xenocrysts of gabbro-felspar are rare in the specimens
sliced, but they are occasionally found, especially in the neighbour-
hood of actual gabbro-xenoliths. One suitably oriented crystal gave
extinction-angles 35° and 36° in alternate lamelle, and is presumably
labradorite like the common felspar in the gabbros of the district.
It has a marginal intergrowth of a more acid felspar, and, like the
felspar-phenocrysts in all these granophyres, has served as nucleus
for a growth of micropegmatite (6704). It is clear that most of
the felspar of the enclosed gabbro-fragments has been completely

absorbed by the enveloping magma. The result is seen in a great

preponderance of soda-lime over potash-felspar in the rock as finally
consolidated, compared with the normal granophyres of the district.
This dominant felspar seems, however, to be chiefly the usual
oligoclase, with quite low extinction-angles. At Barnavave xeno-
erysts of felspar (bytownite) seem to be common, though they are
described as showing corrosion and other signs of change.

Apart from the peculiarities described, the rocks here dealt with
present a general similarity to the normal granophyres. There are,
however, one or two special points worth noting. Several writers,
in describing the phenomena of xenoliths of acid rocks in basalts
and diabases, have remarked a tendency to the formation of hollow
spaces, usually filled by later products. Indications of the same
tendency are not wanting in the present converse case, though

Z2

326 MR. ALFRED HARKER ON THE [May 1896,

the circumstances are different. In one example are seen ring-like
aggregates, about 54, inch in diameter, of hornblende-crystals, sur—-
rounding areas of clear quartz (6705, Pl. XIII. fig. 6). Quartz is
frequently seen moulded upon hornblende-crystals, and, in several
slides, penetrated by actinolitic needles (Pl. XIII. fig. 5). Such
patches of quartz are quite different from the quasi-porphyritic grains
common in the granophyres, and they seem to be of late formation—
not necessarily secondary in the usual sense. They probably occupy
what have once been vacant spaces formed in connexion with the
destruction of xenoliths, and are quite distinct from druses. The
latter are also found here just as in the normal granophyres, and:
are commonly filled by calcite and quartz (6707, Pl. XIV. fig. 8)..
In places it can be seen that the calcite-crystals project into the
quartz, which again indicates that some of the latter mineral belongs:
to a very late stage in the history of the rock.

In addition to the relics of gabbro in these granophyres there are
occasional traces of inclusions of other rocks. In particular there are:
granular aggregates consisting largely of hornblende and magnetite:
and presenting angular outlines to the surrounding matrix (6709,
Pl. XIV. fig. 10). These probably represent xenoliths of basalt in an:
advauced stage of dissolution. At junctions of basalt and granophyre
in other parts of Skye, as wellas in Rum, Mull, and Ardnamurchan,.
detached fragments of basalt in the granophyre can be traced down
to quite similar aggregates. In some cases the ferro-magnesian
mineral produced is augite; in other cases, as here, it is hornblende.
The greater part of the rocks now described contain no trace of
foreign fragments other than, those of gabbro.

There are, however, certain fine-textured portions of these
granophyre-masses to which allusion has not yet been made, and
the xenoliths in these are of a different character. The rocks occur
on the margin of an intrusion or as a limb extending from the
main body, and it is not easy to decide whether these and the
more usual coarse type represent parts of a single intrusion. The
granophyric structure is absent or scarcely developed in these fine-
grained rocks, and one example shows strong fluxion (PI. XIV.
fig. 12). The enclosed fragments are very distinctly seen in hand--
specimens, are subangular to rounded in shape, and are chiefly of dark
compact lava, usually not more than 1 inch in diameter. One slide
shows recognizable pieces of basalt, partly vesicular, of microlitic
andesite, and of a quartzose grit (6701, Pl. XIV. fig. 11). Another
shows only basalts, one with porphyritic felspars (6702). Gabbro
has not been identified, and the fragments noticed are all such as
might be obtained from the agglomerate through which the intrusions.
have broken. They are in no case very highly altered, and, though
their rounded form points to a certain amount of absorption by the
magma, the latter has clearly not been very considerably enriched in
basic constituents. In all these points these rocks contrast with the
coarser granophyres described above.

The fine-textured rocks, with their evidence of comparatively
rapid chilling, presumably represent the earliest irruptions of the’
acid magma. The marked difference between them and the coarser

Vol. 52.] GRANOPHYRES OF STRATH (SKYE). 327

granophyres seems to point to a distinct separation between them
in respect of time and of the circumstances attending intrusion, and
the contrast between the xenoliths of the two types decidedly
enforces this reasoning. The portion of the acid magma first
intruded appears to have merely enclosed fragments derived from
the bounding walls, as many other igneous rocks have done in this
and other districts. The main body of the granophyre-magma, which
‘followed perhaps after some interval of time, has taken up foreign
material amounting to fully 7 of its own bulk, derived, not from
the bordering rocks, but from a gabbro probably at a consider-
able depth beneath. Herein, too, this latter case differs from the
examples already cited from other districts. At Barnavave, where
the evidence seems to be singularly complete, the phenomenon is
essentially a ‘contact’ one. At Carrock Fell, owing to special cir-
cumstances upon which I have remarked elsewhere, the dissolution of
the derived fragments has proceeded much farther than in the Irish
example, but the broad relations are the same. The modification
of the granophyre is confined to the neighbourhood of its contact
with the gabbro, and disappears rapidly as we recede from that
contact. In the instance now described in the Strath district, on
the other hand, the abundant foreign material has been taken up
prior to the intrusion of the magma into its present surroundings ;
has been distributed with some approach to uniformity prior to or
during the intrusion ; and, except for the relics described above,
has then been absorbed into the granophyre-magma. The whole
mass of each intrusion, excluding the fine-textured non-granophyric
portions, has the same general characters throughout.

A question of general interest naturally arises from a consideration
of this case. If the caustic action of the acid magma had been from
any cause more energetic, and had sufficed to destroy the relics of
gabbro as completely as has been effected at Carrock Fell, it would
have been impossible (without careful and specially directed search)
to detect any evidence of the incorporation of foreign material. Is,
then, this factor an important one to be taken into account in
discussing the origin of igneous rocks in general? Prof. Sollas,
Dr. Johnston-Lavis,* and some other geologists would probably
-answer this question in the affirmative: I refrain from expressing
any opinion.? The facts detailed above admit of obvious application
to the problem ; but it may be urged on the other hand that, were
complete absorption of xenoliths to modify the composition of a
rock-magma a frequent occurrence, cases of incomplete absurption
such as that here described should be more common than they
appear to be.

1 Geol. Mag. 1894, pp. 47-48, 252-254; ‘Natural Science,’ vol. iv. (1894)
pp. 134-140. Comp. A. von Lasaulx, Neues Jahrb. 1870, p. 713.

2 Prof. Brogger has recently stated with much cogency the argument against
the hypothesis of Kjerulf, Michel Lévy, and others, which supposes that granite-
intrusions have in general ‘assimilated’ large portions of the neighbouring
-solid rocks. See ‘Die Eruptivgesteine des Kristianiagebietes,’ pt. ii. pp. 116,
et seqg., Videnskabsselskabets Skrifter, I. Mathematisk-naturv. Klasse, 1896,
No. 7.

328

MR. ALFRED HARKER ON THE [May 1896,

EXPLANATION OF PLATES XIII. & XIV.

[The numbers in brackets are those of the figured slides in the collection of the

Geological Survey at the Jermyn Street Museum. |

Puate XIII.

Fig. 1. [6704.] x20. Granophyre showing native and foreign augites. To

Fig.
Fig.
Fig.

Fig.
Fig.

Fig.

Fig.

Fig.

2.

J.

4
5

6.

Q

8.

9.

the right of the magnetite in the centre are several granules of
augite proper to the granophyre: to the left of the figure is a
gabbro-xenolith but little altered. In this the pale, well-cleaved
augite forms ophitic plates enclosing the felspar, and the only
alteration is a little marginal conversion into hornblende. The
basal striation is not seen here. See p. 324.

[6705.] x40. Granophyre showing xenocrysts of augite derived from
gabbro. This is proved by their retaining the basal striation and.
schillerization, which is combined with the ordinary orthopinac-
oidal twinning to give the ‘ herring-bone’ structure. See p. 324.

[6709.] x20. Similar augite-xenocrysts converted into hornblende, but
still retaining the basal schillerization. See p. 324.

[6705.] x 150. Granophyre showing native hornblende. This is
proved by its crystal-form. See p. 324.

[6708.] x 150. Also showing idiomorphic hornblende, and, in addi-
tion, actinolitic needles embedded in clear quartz. See p. 326.

[6705.] x20. Ring of hornblende-crystals surrounding an area
of clear quartz, to which they present idiomorphic outlines.
See p. 326.

Puatse XIV.

[2674.] x20; polarized light, crossed nicols. Granophyre containing:
a xenocryst of enstatite, probably derived from gabbro. The
interior of the crystal is converted into the usual serpentinous.
pseudomorph, but the margin is replaced by fibrous hornblende.
Towards its right-hand end the crystal encloses two or three patches
of compact hornblende, probably an original intergrowth. See

p. 325.

[6707.] x20; polarized light, crossed nicols. Granophyre with druse,
occupied by quartz and calcite; a feature common to the ordinary
coarse granophyres of the district. See p. 326.

[6707.] X20; polarized light, crossed nicols. Granophyre showing
delicate micrographic intergrowths of felspar and quartz. ‘This also
is characteristic of the ordinary granophyres of the district, from
which the rocks described (when not showing actual relics of foreign
ee! differ only in their greater richness in the coloured
minerals,

Fig. 10. [6709.] x20; polarized light, crossed nicols. An angular patch rich

in hornblende and magnetite, probably an altered xenolith of
basalt. See p. 326.

Fig. 11. [6701.] x20; outlines drawn by polarized light, crossed nicols. Fine-

textured variety of granophyre (but non-granophyric), containing
various xenoliths. In the lower part of the figure are fragments of
altered glassy basalt ; above and to the right is a piece of quartzose
grit, and to the left of this a felspar-xenocryst. See p. 326.

Fig. 12. [6702.] x10. Another fine-textured example, showing flow-structure.

There are numerous xenoliths, chiefly of basalt, the smaller ones.
lenticular in form and arranged along the stream-lines. See

p- 326.

Vol. 52.] GRANOPHYRES OF STRATH (SKYE). 329

Discussion.

Sir ArcurBaLp Geixre referred to the fact that Mr. Harker had
been appointed to the Geological Survey ouly last spring, and that
the present paper was the result of his tirst season’s work. The
region described by the Author was exceedingly familiar to the
speaker, and he rejoiced to welcome this application of modern
petrographical methods to its investigation. The paper had a double
value. In the first place, it was important in regard to the local
geology of the Western Isles, for it demonstrated by new evidence
the posteriority of the granophyres to the gabbros ; and in tue second
place, it had a suggestive bearing upon questions of theoretical
interest regarding the possible modification of eruptive rocks by the
incorporation of foreigii material into their substance. He felt sure
that further and even more extensive evidence of the same kind
would be encountered in other parts of the same region of Skye.
The inspection of Mr. Harker’s specimens reminded the speaker of
some puzzling rocks on the flanks of Glamich and other hills, which
many years ago he saw to be too acid for the gabbros and too basic
for the granophyres. He looked forward to having these and many
other problems solved by the continuation of the same patient and
skilled observation as had been shown in the investigations described
in the present paper.

Lieut.-Gen. M°Manon said that he had listened to Mr. Harker
with great interest, and looked forward with pleasure to studying
the details of the paper. He was quite prepared to accept the
Author’s conclusions, because he had found augite in the granite of
the Chor Mountain, North-western Himalayas, and attributed its
presence to the digestion of fragments of basic rocks caugit up by
the granite. Mr. R. D. Oldham, Superintendent of the Geological
Survey of India, had also found hornblende locally abundant in the
granite of one part of the Chor, and attributed it to the granite
having ‘ dissolved and absorbed the rocks whose position it occupies.’
The presence of magnetite, however, stood on a diifereut footing.
It was rather abundant throughout the granite of the North-western
Himalayas ; but if the Author could show that its presence in the
granophyre of Skye was due to the assimilation of gabbro, the fact
would be very interesting.

Prof. Mrers called attention to a large mass of coarsely-granular
basic rock which exists in the granophyre on the western flank of
Marsco, and may be distinguished from the summit of Scuir-na-
Gillean as a dark band about 20 feet in breadth, traversing the face
of the hill in a vertical direction.

Mr. W. W. Warts pointed out that Prof. Sollas’s researches at
Barnavave had prepared the Society for this paper. He ailuded to
the association of gabbro and granophyre at so many places, including
Radnor and Carrock Fell, and pointed out that the Whin Sill at
Caldron Snout passed into a rock which was practically a gabbro
embedded in granophyre.

Dr. Du Ricne Pretier said that already on a former occasion

330 THE GRANOPHYRES OF STRATH (SKYE). [May 1396,

he had pointed out that Sir Archibald Geikie’s conclusions with
respect to the granophyre of the Western Islands of Scotland being
intrusive into the gabbro, and therefore younger than the latter,
were strikingly confirmed by the precisely similar phenomenon in —
the Island of Elba, where the Tertiary granite traversed the gabbro,
diabase, and serpentine dykes. Mr. Harker had now shown the
same phenomenon to exist also in Skye, and the speaker therefore
wished to emphasize the analogy of Elba, the more so as Gen.
M°Mahon had brought forward similar evidence with reference to
the Himalayas.

Mr. Barrow drew attention to the strong contrast between the
evidence adduced by the Author to show actual absorption of part
of these inclusions, and that published some time ago in his and
Mr. Marr’s work on the metamorphic aureole surrounding the Shap
Granite. In the latter case, the Authors selected the amygdules
in certain altered igneous rocks, and produced exceptionally clear
evidence of the extremely limited migration of material that accom-
panied the development of new minerals in these bodies. Experience
has shown that some of our best data are obtained in searching for
the cause of such widely differing results, At present the evidence
seems to suggest that the ‘initial depth temperature’ may be one of
the chief factors in determining the amount of change produced.

Mr. Ruttey asked for further information regarding the geological
structure of the area represented inthe diagram. It was suggestive
of proximity to a centre of eruption, and the irregular character of
the patches mapped as gabbro-bearing granophyre, and their asso-
ciation with volcanic agglomerates and bedded lavas, favoured this
belief. Cases such as this, of the absorption of fragments of a
basic rock by an acid one, were, he thought, of comparatively rare
occurrence. ‘The reverse was more frequently the case. The ex-
posures, described as dykes, might possibly be portions of buttress-
dykes cutting irregularly through the agglomerates. The paper
dealt with several points of great interest.

The PresipEnt also spoke.

The Avruor briefly replied, thanking the speakers for their
appreciation and criticism. Though the phenomena of incorporation
of basic material by an acid magma appeared to be uncommon, at
least on such a scale as in the examples described, the converse case
of acid rocks absorbed into basic was illustrated by very many dykes
in the Skye district. A considerable difference in acidity between
the absorbed and the absorbing rock seemed to be as essential a
factor in the process as that of temperature ; hence the absorption
of gabbros by granophyres observed in several districts. The
peculiar intrusions described were possibly somewhat younger than
the normal granophyres of Skye; but wherever these latter were
seen in junction with gabbros in the area as yet mapped by the
Author, the same relation, namely, the acid intrusion succeeding
the basic, was invariably verified.

Quart. Journ.Geol.Soc.Vol.LI. Pl. XI.

F.H.Michael del.et hth. Mintern Bros. .omp.
GRANOPHYRES WITH FOREIGN INCLUSIONS

Voli. PLE.

Co
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art. Journ.Geo

Qu

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Mintern Bro s.irm

F.H Michael.del et lth.

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GRANOPHYRES WITH FOREI

‘Vol. 52.] THE TERTIARY BASALT-PLATEAUX OF N.W. EUROPE. 331

19. The Tertiary Basart-prateavx of NortH-western Evrorre, By
Sir Arcursatp Gerxre, D.Sc., LL.D., F.R.S. (Read December

18th, 1895.)
[Puates XV.—-XIX.]

ConrTENTs.
Page
CED VS Seah) Ce SO ee ae a ee ae ae ees 331
GE ARCs aA AS) «aren etcegepiceetasinik nliinee'atesidels vevscanseues 332
UROIN EAC GUAR ce thee crane ee Lie ca de Ak caplile vis'enlan'e drencusenaeupacine 342
PP The Rivers Of the: V Gleam Period .5. occas ovccesssesciccchomsnnvese 354
ve Hae Pate itiny tere ete eae, ee oe oils ebepesbavdenensowes 373
Pie Me RSE eee ree AP a same pendence = ndeials weibininn onlnice his ovo sisleosmninn’ 382
ris he am estye GAD DTOS ds ccs dec csascuasunepcancas eosncopesssisecone 384
Wie Phe Granophyre: MirusiONs i.sdeocewcsee<asedsscnescanesenes scans 389

VIII. Modern Volcanic Action in Iceland, as illustrative of the
History of the Basalt-plateaux of North-western Europe. 395

ee Pree aulinves the, PlAteam, 15, oc dadcenssnaenenssscecassncaceseneroes 399
EEG, ECLA Gl CHUGATIOM: J.cccccsaansewadcsasradedeasosewcavesres 402
INTRODUCTION.

Srnce the publication, seven years ago, of my memoir on ‘The
History of Volcanic Action during the Tertiary Period in the
British Isles,’ ’ I have continued the investigation of this subject.
My researches in this interval have included a re-examination of
various tracts in Mull, Rum, Raasay, and Skye; numerous traverses
in the last-named island, especially over areas which had not been
previously described by any geologist; a detailed survey of Canna
and its adjacent islets ; an exploration of the Shiant Isles and other
insular outliers of the Tertiary sills, and a visit to St. Kilda for the
purpose of accurately determining the relations of its two great
groups of igneous rocks. In two successive years I have prolonged
my excursions into the Faroe Islands, where the phenomena of our
basaltic plateaux are reproduced on a colossal scale, and where the
numerous fjords and sounds have laid bare the most stupendous
range of geological sections. This extended series of observations,
while entirely confirming the main conclusions announced in my
former memoir, has furnished many fresh and important illustrations
of phenomena already described, and some new and interesting
additions to our knowledge of the volcanic history of Tertiary time
over the North-west of Europe. I now lay before the Society an
outline of the chief results which have thus been obtained.”

1 Trans. Roy. Soc. Edin. vol. xxxv. (1888) pp. 21-184.

? It is a pleasure to acknowledge the great assistance which has been kindly
afforded to me in these i I am specially indebted to my friend
Mr. Henry Evans, who, by placing his steam-yacht Aster at my disposal,
enabled me to visit many localities among the Inner Hebrides and outer islands
which are not easily accessible, and to make acquaintance with the whole group
of the Faroe Islands. His brother, Col. John Evans, photographed for me

332 SIR A. GEIKIE ON THE TERTIARY [May 1896,

As the literature of the subject was fully summarized in my
former memoir, it need not be further referred to here. Such more
recent papers as bear on any of the localities which I shall have to
describe, or on any of the questions I shall discuss, will be cited as
the occasion arises.

I, Tor Pratrav-Lavas.

Every tourist who has sailed along the cliffs of Antrim, Mull,
Skye, or the Faroe Islands is familiar with the singular terraced
structure of the great volcanic escarpments which stretch as mural
precipices along these picturesque shores. Successive sheets of lava,
either horizontal or only gently inclined, rise above each other from
base to summit of these walls, as parallel bars of brown rock with
intervening strips of bright green grassy slope.

The geologist who for the first time visits these coast-lines is.
impressed by the persistence of the same lithological characters
giving rise to the same topographical features. He soon realizes
that the plateaux, so impressively truncated by the great escarp-
ments that spring from the edge of the sea, are built up essentially of
dark lavas,—basalts, dolerites, and andesites,—and that fragmental
volcanic accompaniments, though here and there well developed,
play on the whole a quite insignificant part in the structure and
composition of those thick piles of volcanic material. Closer exa-
mination in the field enables him to ascertain that, regarded as rock-
masses, the lavas include four distinct types :—

(1) Thick, massive, prismatic or rudely-jointed sheets, rather
more coarsely crystalline and obviously more durable than the other
types—inasmuch as they project in tabular ledges and tend to retain
perpendicular faces, owing to the falling away of slices of the rock
along the lines of vertical joint. Many rocks of this type are
undoubtedly intrusive sheets, and as such will be further referred to in
a later part of this paper. But the type includes also true superficial
lavas which show the characteristic slaggy or vesicular bands at
their upper and lower surfaces. The mere presence of such bands
may not be enough, indeed, absolutely to establish that the rock
possessing them flowed at the surface as a lava, for they are occa-
sionally, though it must be contessed rarely, exhibited by true sills.
But the rough scoriaceous top of a lava-stream, the presence of
fragments of this surface in the overlying tuff, or wrapped round
by the next succeeding lava sufticiently attest the true superficial
outflow of the mass.

(2) Slaggy or amygdaloidal lavas without any regular jointed
structure, but often with roughly scoriform upper and under layers,
and tending to decay into brown earthy débris. Some of the upper

many poiuts of geological interest met with in our cruises. The pleasant hos-
pitality of Mr. Thom, the proprietor of Canna, enabled me to survey in great
detail on the 6-inch map of the Ordnance Survey the deeply interesting
geology of his island-home, and to revisit Hysgeir, while Miss Thom took
photographs for me of some of the more striking geological features of Canna.
and Sanday.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESIERN EUROPE. 333

surfaces of such sheets among the Tertiary basalt-plateaux must
have resembled the so-called ‘Aa’ of the Sandwich Islands. A
striking example of the structure may be noticed at Camas Thar-
bernish, on the northern coast of the island of Canna. There the
hummocks on the upper surface of a slaggy basalt measure about 15
feet in breadth, and rise about 3 feet above the hollows between
them like a succession of waves (see fig. 1, p.334). The steam-holes
are disposed in a general direction parallel to the strike of the
hummocks.

Great variety obtains in the size and shape of the vesicles. Huge
cavities a foot or more in diameter may occasionally be found, and
from such an extreme every gradation may be traced down to
minute pore-like vacuoles that can hardly be made out even with a
strong lens. In regard to the deformation of the vesicles, it is a
familiar general rule that they have been drawn out in the direction
of the flow of the original lava. Occasionally this elongation has
advanced so far that the cavities have become straight, narrow
pipes, several inches long, and only an eighth of an inch or so in
diameter. A number of such pipes, arranged parallel to each other,
resembles a row of worm-burrows. Remarkable illustrations of
such extreme mechanical deformation by the movement of a still
molten rock may be collected in Mull and Skye.’

It is a common belief that the filing-in of the steam-cavities
has taken place long subsequent to the volcanic period by the slow
percolation of meteoric water through the rocks. I believe, how-
ever, that at least in some cases, if not in all, the conversion of the
vesicular lavas into amygdaloids was effected during the volcanic
period. Thus it can be shown that the basalts which have been
disrupted by the gabbros were already amygdaloidal before these
basic intrusions disturbed them, for the kernels of calcite, zeolite,
etc., have shared in the general metamorphism induced in the
enclosing rock. Again, the blocks of amygdaloid contained in the
agglomerates of the volcanic series are in every respect like the
amygdaloidal lavas of the plateaux. It would thus seem that
the infilling of the cavities with mineral secretions was not
merely a long secular process of infiltration from the cool atmo-
sphere, but was more rapidly completed by the operation of warmer
water, either supplied from volcanic sources or heated by the still
high temperature of the cellular lavas into which it descended from
the surface.”

1 Some examples have been deposited by me in the Museum of Practical
Geology, Jermyn Street, in the case illustrating rock-structures. The elonga-
tion of the vesicles into annelid-like tubes may be observed among the stones
in the volcanic agglomerates.

? Messrs. Harker and Marr have demonstrated that the Lower Silurian
vesicular lavas of the Lake District had already become amygdaloids before
the uprise of the Shap Granite, Quart. Journ. Geol. Soc. vol. xlix. 1893.
J. D. Dana, originally an advocate of infiltration from above, subsequently
supported the view here adopted, that the kernels of amygdaloids were filled in
by the action of moisture within the rocks during the time of cooling (Am.
Journ. Sci. ser. 3, vol. xx, 1880, p. 531).

334 SIR A. GEIKIE ON THE TERTIARY [May 1896,

Except in the elongation of the vesicles in one general direction,
the amygdaloidal basalts seldom display any distinct trace of flow-
structure. Occasionally, however, a striking exhibition of this
structure may be seen among them. Thus at the top of the Dun
Can, the highest summit of the island of Raasay, a small outlier of
the plateau-lavas is capped with a black olivine-basalt, having a
strongly-pronounced vesicular structure, wherein the cavities are
filled with zeolites. The weathered faces of this rock show rudely
parallel, puckered, and broken lines that mark the layers of devitri-
fication in the original flowing lava.

(3) Prismatic or columnar basalts, which, as at the Giant’s
Causeway and Staffa, have long attracted notice as one of the most
notable topographical elements in the structure of the plateaux.
Though generally rather compact, becoming indeed dense, almost
vitreous rocks in some sheets, they are often more or less cellular
throughout, and highly slaggy along their upper and under surfaces,
In some cases, as in that of a prismatic sheet which overlies the
rough scoriaceous lava of Camas Tharbernish just referred to, the
rows of vesicles are disposed in lines parallel to the under surface
of the sheet (fig. 1).

Fig. 1.—Section of scoriaceous and prismatic basalts. Camas
Tharbernish, northern shore of Canna Island.

As I have already remarked with regard to the massive, rudely-
jointed sheets, many of the most perfectly columnar rocks of the
plateaux are not superficial lavas, but intrusive sills, bosses or
dykes. Conspicuous examples of the sills are displayed on the coast —
of Trotternish in Skye, of the bosses and dykes at the eastern end —
of Canna. To these further reference will be made in the sequel.
It is not always possible to be certain that columnar sheets which
are regularly intercalated among the undoubted lavas of the volcanic
series may not be really intrusive. In some instances, indeed, we
can demonstrate that they are so, when, after continuing perfectly
parallel with the lavas above and below them, they eventually break
across them. One of the most remarkable examples of this feature
is supplied by the great sill of the south-west of Stromé in the
Faroe Islands, of which I shall give some account in a subsequent
section of this paper (figs. 9, 24, & 25, pp. 345, 380, 381).

(4) Banded or stratiform lavas, consisting of successive parallel
layers or bands which weather into projecting ribs and flutings.
The deceptive resemblance to sedimentary rocks thus produced

Vol. 52.] BASALI-PLATEAUX OF NORTH-WESTERN EUROPE. 335

has no doubt frequently led to these lavas being mistaken for tuffs.
As I have recently found them to be much more plentiful than I
had supposed, a more detailed description of them seems to be
required.

The banded character arises from marked distinctions in the
texture of different layers of a lava-sheet. In some cases these
distinctions arise from differences in the size of the crystals or in the
disposition of the component minerals of the rock ; in others, from
the varying number and size of the vesicles, which may be large or
abundantly crowded together in some layers, and small or only
sparsely developed in others. ‘The structure thus points to original
conditions of the lava at the time of its emission, and may be regarded
as, to some extent, a kind of flow-structure on a large scale.

Where the banding is due to differences of crystalline texture,
the constituent felspars, augites, and iron-ores may be seen even
with the naked eye as well-defined minerals along the prominent
surfaces of the harder ribs, while the broader intervening flutings
of finer material show the same minerals in minuter forms. The
alternating layers of coarser and finer crystallization lie, on the
whole, parallel with the upper and under surfaces of the sheets in
which they occur. But they likewise undulate like the streaky
lines in ordinary flow-structure.

Banded structure of this type may be seen well developed in the
lower, parts of the basalt-plateaux throughout the Inner Hebrides
and the Faroe Islands. A specimen taken from the western end of
the island of Sanday, near Canna, which showed the structure by a
conspicuous parallel fluting ou weathered surfaces, was sliced for
microscopical examination. My colleague, Mr. Alfred Harker, to
whom I am indebted for the notes on the microscopic characters of
rocks described in the present paper, has been kind enough to supply
me with the following observations regarding this slice :—

‘In the slice [6660]* the banding becomes less conspicuous
under the microscope. The rock is of basaltic composition, and,
with reference to its micro-structure, might be styled a fine-grained
olivine-diabase or olivine-dolerite in some parts of the slice, an
olivine-basalt in others. It consists of abundant grains of olivine,
imperfect octahedra and shapeless granules of magnetite, little
simple or twinned prisms of labradorite, and a pale brown augite.
The last-named mineral is always the latest product of consolidation,
but it varies in habit, being sometimes in ophitic patches moulded
upon or enclosing the other minerals, sometimes in small granules
occupying the interstices between the felspars and other crystals.
The ophitic habit predominates in the slice, while the granulitic
comes in especially along certain bands. If the former be taken as
indicative of tranquil conditions, the latter of a certain amount of
movement in the rock during the latest stages of its consolidation,
the banding, though not strictly a flow-structure, may be ascribed

‘The figures within square brackets throughout this paper refer to the

nuwbers of the microscopic slides in the Geological Survey (Scotland) collection,
where I have deposited all those prepared from my specimens.

386 SIR A. GEIKIE ON THE TERTIARY [May 1896,

in some degree to a flowing movement of the nearly solidified rock.
‘There is, however, more than this merely structural difference
between the several bands. They differ to some extent in the
relative proportions of the minerals, especially of olivine and augite ;
which points to a considerable flowing movement at an early stage
in a magma which was initially not homogeneous.’

Where the banding arises from the distribution of the vesicles, some-
what similar weathered surfaces are produced. In some instances,
while the basalt is throughout finely cellular, interposed parallel
bands of harder, rather finer-grained and less thoroughly vesicular
characters serve to give the stratified appearance. Instances may be
observed where the vesicles have been crowded together in certain
bands, which consequently weather out differently from the layers
above and below them. An excellent illustration of this arrange-
ment occurs in the lowest lava but one of the largest of the three
picturesque stacks known as Macleod’s Maidens, on the western coast
of Skye. This lava is thoroughly amygdaloidal, but the vesicles are
specially crowded together in certain parallel bands from 1 to 3
or 4 inches thick. Some of
these layers lie close to each Fig. 2.—Banded amygdaloidal basalt

other, while elsewhere there showing layers of elongated and
may be a band of more close- steeply inclined vesicles. Macleod’s
erained, less vesicular material Maidens, Skye.

peuwesn them. But the most
singular feature of the rock SSS aS sys.

is to be seen inthe shape and °.- ete bet 3 hee ue Donel
position of the vesicles that - iE fo dike
are crowded together in the Re LON wes aw aS
q uw SAE «
cellular bands. Instead of \ NY Ys SN ~ a pee
being drawn out into flattened vies Fb es
om ise, - vse oe * =

forms in the general direction
of banding, they are placed ms
together at high angles. Each 3}
layer remains parallel to the
general bedding, but its vesicles are steeply inclined in one direction,
which doubtless indicates the flow of the still unconsolidated lava.
Weathering along these bands, the lava might easily be mistaken
at: a little distance for a tuff or other stratified intercalation.
Banded lavas possessing the characters now described are of
frequent occurrence among the Inner Hebrides. Many striking
examples of them may be seen along the western coast of Skye. Still
more abundant in Faroe, they form one of the most conspicuous
features in the geology of that group of islands. Along the whole
of its western seaboard, on island after island, they are particularly
prominent in the lower parts of the precipices, while the upper parts
consist largely of amorphous or prismatic sheets. So much do
they resemble stratified rocks that it was not until J had landed at

2
‘he ‘“ ace of L ae
ee °e

+

s

Ne SORA

1 This elongation of vesicles more or less perpendicular to the general
bedding may be noticed sometimes even in sills, as will be shown farther on. —

Vol. 5. BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 337

various points that I could satisfy myself that they are really
banded lavas.”

On a first inspection any one of the great basalt-precipices seems
to consist of regularly persistent sheets, which are continued from
headland to headland, like strata of sandstone or limestone. TI have
dwelt on the deceptive nature of this apparent continuity, and have
shown that when more closely examined these cliffs contain many
proofs that, while the general bedding of the basalts is prolonged
with much regularity, individual sheets may be seen to die out or
to begin. I have insisted that these cessations do not occur in any
general direction, that they furnish no evidence of any great central
vents from which the lavas proceeded, but that on the contrary they
show the eruptions to have probably taken place from many scattered
vents and in every direction.

My recent journeys have furnished many additional proofs of the
truth of this generalization. Closer scrutiny of the western cliffs
of Skye last year, and again this summer, has brought to light
numerous examples of the gradual or rapid disappearance of laya-
beds, now in one direction, now in another. I may especially cite
the great headland south of Talisker Bay, which reaches a height of
400 feet, and where, in the pile of nearly horizontal sheets, two beds
may be seen to die out, one towards the north, the other towards
the south. Farther north, in the cliff of the Hoe of Duirinish, 759
feet high, a similar structure presents itself. Owing to their greater
exposure of bare rock, the sea-walls of the Faroe Islands furnish
even more striking examples of discontinuity. On the western side
of Suderé, lenticular beds of basalt form a conspicuous feature in the
precipices that stretch northward from the highest headland. On
Strom6 the same structure occurs. Similar features arrest the
attention on the precipices of Sando, where, though at first sight
the basalts seem to be regular and continuous, a nearer view of
them reveals such sections as that shown in fig. 3, p. 338, where a
group of sheets rapidly dies out towards the north against a thicker
band that thins away in the opposite direction. Farther north we
come upon other examples in the range of low cliffs between
Kirkebonaes and Thorshaven, and more impressive still in the
rugged precipices that face the Atlantic on the western front of Hesté
(fig. 4, p. 338), where the disappearance is in a northerly direction.

But it is in the northern part of the Faroes, where the basalt-
plateau has been so deeply trenched by parallel fjords as to be
broken up into a group of long, narrow, lofty, and precipitous
insular ridges, that the really local and non-persistent character of

1 Tt is not necessary to give here a synopsis of the geological literature of the
Faroe Islands. I may, however, refer to some recent papers, particularly to
one by Prof. James Geikie (Trans. Roy. Soc. Edin. vol. xxx. 1880, p. 217); one
by Prof. A. Helland (Dansk. Geografisk Tidskr., 1881); R. Bréon, ‘ Notes pour
servir 4 l’Etude de la Géologie de l’Islande et des Iles Feroe,’ 1884; and one by
Mr. J. Lomas, Proc. Geol. Soc. Liverpool, vol. vii. (1895) p. 292. Various
writers have treated of the petrography, particularly A. Osann, Neues Jahrb.
1884, vol. i. p. 45. and Bréon. Banded lavas are noticed by J. Geikie, op. cir.

338 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

the lavas can best be seen. The eastern cliffs of Svino present
admirable examples, where in the same vertical wall of rock some
of the basalts die out to the south, others to the north, while occa-
sionally a shorter sheet may be seen to disappear in both directions

as if it were the end of a stream that flowed at right angles to the
others (fig. 5, below).

Fig. 3.—Dying out of lava-beds, eastern side of Sandé, Faroe Isles.

AAA

|
BPN] diya 7M
i! a) ine au a i
i, ii!
De i =

aoc om are jis fa SERS oss
The islands of Kalsé and Kuno6 display the most impressive
scenery of the plateau-basalts of Faroe. In these northern climes

vegetation spreads less widely over rock and slope than it does in

Fig. 4.—Lenticular lavas, western front of Hesto, Faroe Isles.

Cae tt
7] i TLL TTT

the milder air of the Inner Hebrides. Hence the escarpments
sweep as vast walls of almost bare rock from the level of the sea
up to the serrated crests of the islands, some 2000 feet in height.
Each individual bed of basalt can thus be followed continuously

Fig. 5.—Lenticular lavas, eastern side of Svind, Faroe Isles.

pT Weber inh EZT TT

Ty, ia 4
lls TY
eae IOI say

: \ en CUD
ST GIAARIGRaIE lt IN yt

along the fjords, and its variation or disappearance can be readily
observed. Coasting along these vast natural sections, we readily
perceive that the successive sheets of basalt have proceeded from
no one common centre of eruption. They die out now towards one

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 339

quarter, now towards another, yet everywhere retaining the universal
regularity and gentle inclinations of the whole volcanic series.

These bare rocky fronts, while permitting us to observe the want
of continuity in many of the basalts, likewise afford an opportunity
of following any particular sheet over the whole of its outcrop. I
was particularly struck by the persistence of a dark band of basalt
in the lower part of the western declivity of Kuné. This sheet
can be kept in sight along the whole length of the island, at least
from a point opposite to Mygledahl in Kalsé, with the exception of
a short concealed space of detritus at the mouth of the recess behind
the village of Kuno. It may possibly be even prolonged into the
island of Bord, for a similar band is seen occupying the same
position there. Its length on Kuné must be at least 6 nautical miles.

The more the basalt-plateaux of Britain and the Faroe Islands
are studied, the more certain does the conclusion become that these
widespread sheets of lava never flowed from a few large central
voleanoes of the type of Etna or Vesuvius, but were emitted from
innumerable minor vents or from open fissures. In a later part of
this paper a number of the vents, which may still be seen under
the overlying sheets of basalt, will be described, and I shall point
out their resemblance to modern volcanic vents on the great lava-
fields of Iceland.

In looking at one of the sea-cliffs of the Inner Hebrides or of
the Faroes, and in following with the eye its successive sheets of
lava in orderly sequence of level bands from the breaking waves at
the base to the beetling crest above, we are apt to take note only
of the proofs of regularity and repetition in the outflows of molten
rock and to miss the evidence that these outflows did not always.
rapidly follow each other, but were separated by intervals of vary-
ing, sometimes even of long, duration. The layer of red bole or
decomposed lava, so often observable between the flows, has long
been regarded as evidence of the lapse of an interval sufficiently
extended to permit of considerable subaerial decay of the surface of
a lava-sheet before the outflow of the next lava. But an attentive
study of the plateaux discloses other and even more remarkable indi--
cations that the pauses between the consecutive basalt-beds were
frequently so prolonged as to allow of extensive topographical
changes being made in a district.

The occurrence, for example, of interstratifications of different
kinds of sedimentary material among the lavas sufficiently demon-
strates the reality of these intervals of quiescence. Where this
material consists merely of volcanic tuff, it may only point to a
continuance of volcanic activity in the form of fragmentary dis-
charges during pauses in the outpourings of molten rock. In general,
however, there is not only tuff but non-volcanic sediment arranged
in definite layers, that show the action of running water. ‘The
various clays (bauxite, lithomarge, etc.) and ironstones which lie
between the basalts of Antrim, besides their geological interest,
have now considerable economic importance. The clays, in par-
ticular, are much in request as sources for the manufacture of
aluminium. Neither among the Western Isles of Scotland nor in

Q.J.G.8. No. 206. 2A

340 SIR A. GEIKIE ON THE TERTIARY [May 1896,

the Faroes has any one definite platform yet been traced out on
which such clays are extensively developed. But various minor
and perhaps more local deposits in these regions might be examined
as possibly available for industrial purposes. One of the most
promising localities lies on the western side of Skye, at the mouth of
Loch Bracadale, where, on the face of the great cliff of Rudha nan
Clach, some conspicuous bands of lilac and red are interspersed
among the basalts. These bands were noticed by Macculloch, who
described them as varieties of ‘iron-clay.’* I have not had an
opportunity of examining them, except from the sea at a little
distance. But they suggest a similarity to some of the variegated
clays between the upper and lower basalt series of Antrim. The
coal-bearing platform of the Faroes might also be followed along its
outcrop, with the object of ascertaining whether any local deposits
of similar clays exist there.

As an illustration of the diversity of deposits sometimes observ-
able between the basalts, I give here a section exposed on the eastern
side of Suderéd in the Faroe Islands—a locality often visited and
described in connexion with its coal-seams (fig. 6). At the base
lies a sheet. of basalt (a) with an
irregularly lumpy upper surface. It Fig. 6.—Section at Frod-

may be remarked that the group of bonyp, Suderé.
basalts below this stratified inter- Qeeeasi

s s COBAIN BZ
calation is marked by the occurrence Toe Oe

of numerous columnar sheets, some
of them possibly sills, and also more
massive, solid, and durable basalts
than the sheets above. The lowest
of the intercalated sediments are
light-coloured clays, passing down
into dark nodular mudstone and dark
shale, the whole having a thickness
of at least 20 feet (6). These strata
are succeeded by (c) pale clays with
black plant-remains, about 3 feet
thick. Immediately above this band
comes the coal or coaly layer (d),
here about 6 inches thick, which im-
proves in thickness and quality farther
inland, where it has been occasionally
worked for economic purposes. <A
deposit of green and brown volcanic
mudstone (e), 12 feet in thickness,
overlies the coal and passes under a well-bedded granular green tuff
and mudstone 3 feet thick (f). The uppermost band is another
voleanic mudstone (q) 4 feet in thickness, dark green in colour, and
more or less distinctly stratified, with irregular concretions, and also
pieces of wood. Above this layer comes another thick overlying
group of basalts (h) distinguished by their abundantly amygdaloidal

1 «Description of the Western Islands of Scotland,’ vol. i. (1819) p. 376.

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE, 341

character, and by their weathering into globular forms which at a
little distance give them a resemblance to agglomerates.

We have here an intercalated group of strata upwards of 40 feet
thick, consisting partly of tuffs and partly of fine clays, which may
either have been derived from volcanic explosions or from the
atmospheric disintegration of basaltic lavas. Through some of
these strata abundant carbonaceous streaks and other traces of
plants are distributed, while among them lies a band almost wholly
composed of compressed vegetation. Unfortunately none of the
strata at this locality seem to have preserved the plant-remains with
sufficient definiteness for identification. There can be no doubt, how-
ever, that they were terrestrial forms like those of Mull and Antrim.

This coal, with accompanying sedimentary deposits, has been
‘traced through Suderé, and another outcrop, possibly of the same
horizon, occurs on Myggenaes, the extreme western member of the
Faroe group, at a distance of some 40 miles,’

Though good coal is not well developed in the Tertiary volcanic
plateaux of the British Isles, I have found coaly layers to be ex-
tremely abundant there. And as the vegetable matter may confidently
be assumed always to indicate terrestrial vegetation, the presence
of these carbonaceous bands may be regarded as good evidence of
some lapse of time between the eruption of the basalts which they
separate. JI have observed that they not infrequently form the
highest member of a group of intercalated sediments between two
‘sheets of basalt. This relation is strikingly exhibited in the isle of
Canna in connexion with the river-gravels, to which more detailed
reference will be made in a later part of this paper. But I may
here cite an interesting example which occurs at the base of the
lofty sea-cliff of An Ceannaich, to the south of Dunvegan Head, on
‘the western coast of Skye (fig. 7).

At the base of the precipice Fig. 7.—Jntercalated group of

ledges of a highly amygdaloidal strata between basalts. An
basalt (a) show a singularly Ceannaich, western coast of
scoriaceous and amygdaloidal Skye.

structure, with abundant and
beautiful zeolites, the hollows
of the upper surface of the
sheet being filled in with dark
brown carbonaceous shale, form-
ing a layer from 1 to 14 inches
thick, marked by coaly streaks
and lenticles (6). A band of
green and yellow sandstone (c)
next supervenes, which, from its
pale colour, attracts attention
from a distance, and led me, a =
while yachting along the coast, OE CS EOR, OO
to land at the locality, in the ;

hope that it might prove to be a plant-bearing limestone. ‘This

1 See in particular J. Geikie, Trans, Roy. Soc. Edin, vol. xxx. (1880) p, 229.
2a 2

B42 SIR A. GEIKIE ON THE TERTIARY [May 1896,

sandy stratum is only some 3 or 4 inches thick at the northern
end of the section, but increases rapidly southward to a thickness-
of as many feet or more, when, owing to the cessation of the
underlying shale, it comes to lie directly on the amygdaloid and to
enclose slaggy portions of that rock. Immediately above the sand-
stone 2 or 3 feet of fissile shale, black with plant-remains (d),
include brown layers that yield to the knife like some oil-shales.
The next stratum is a seam of coal (e) about 1 foot thick, of re-
markable purity. It is glossy, hard, and cubical, including layers.
that break like jet. It has been succeeded by a deposit of green
sand (f), but while this material was in course of deposition
another outpouring of lava took place, whereby the terrestrial pool
or hollow in the lava-field in which the group of sedimentary
materials accumulated was filled up and buried. This lava is
about 20 feet thick, and consists of a coarsely-crystalline, jointed
dolerite with highly amygdaloidal upper and under surfaces. Its.
slaggy bottom has caught up or pushed aside the layer of green
sand, so as to lie directly on the coal, and has there been converted
into that earthy modification so familiar under the name of ‘ white
trap’ among our coal-fields. It is interesting to find that this kind
of alteration, where molten rock comes in contact with carbonaceous:
materials, is not confined to subterranean sills, but may show itself
in lavas that have flowed over a terrestrial surface.

From the frequent intercalation of such local deposits of sedimen-
tary material between the basalts we may reasonably infer that
during older Tertiary time the rainfall in North-western Europe
Was copious enough to supply many little lakes and streams of
‘water. As the surface of the lava-fields decayed into soil, vegeta-
tion spread over it, so that perhaps for long intervals some tracts
remained green and forest-clad. But volcanic action still continued
to show itself, now from one vent, now from another, these wooded
tracts were buried under overflows of lava, and, the watercourses:
being filled up, their streams were driven into new channels, and
other pools and lakes were formed. Some of the evidence for this
part of the volcanic history will be given in the [1Ird section of the
present paper.

Il, Tue Venvs.

Though the abundant vents, which, to judge from the lenticular
nature of the lavas, were dotted over the surface of the Tertiary
volcanic plains, have for the most part been buried under sheets of
molten material, the progress of denudation has laid baresome of them.
It is chiefly along the coast-line that this process of excavation has-
successfully taken place. The interior of the islands is often loaded
with peat, covered with herbage, or strewn with glacial detritus ;
and even where indications of the vents are there to be detected,
it is not always possible to ascertain the true limits and connexions
of these old volcanic chimneys. But where the structure of the
plateaux has been laid bare along ranges of rocky precipice, the
vents have sometimes been so admirably dissected by the sea that

Vol. 52.] BASALI-PLATHAUX OF NORTH-WESTERN EUROPE. 343

every feature of their arrangement can be satisfactorily determined.
In the memoir already cited I have described a number of examples
from the interior. I now proceed to give an account of other
instances from the coast-sections.

I will begin with a group of vents in the Faroe Islands which
display with singular clearness some of the most characteristic
features of this part of the voleanicrecord. And here let me remark
that, although these islands have been so frequently visited and so
often described that their general structure is sufficiently well known,
they present in their details so vast a mass of new material for the
illustration of volcanic action that they deserve a far more minute
and patient survey than they have yet received. They cannot be
adequately mapped and understood by the traveller who merely
sails round them. They must be laboriously explored, island by
island and cliff by cliff. While I cannot pretend to more than a
mere general acquaintance with their structure, I have learnt by
experience that one may sail near their precipices and yet miss
some essential features of their volcanic structure. Last year I
passed close to the noble range of precipices on the western side of
Stromé, at the mouth of the Vaagéfjord, and sketched the sill which
forms so striking a part of the geology of that district (figs. 24 &
_ 25, pp. 380, 381). But I failed to observe an even more remarkable

and interesting feature at the base of the same sea-cliffs. This last
summer, probably under better conditions of light, I was fortunate
enough to detect with my field-glass, from the deck of the yacht,
what looked like a mass of agglomerate. Steaming inshore I was
delighted to find, as the vessel drew nearer to the cliff, that the
agglomerate assumed definite boundaries and occurred in several
distinct patches, until at last it presented the unmistakable out-
lines of a group of vents underlying and overspread by the bedded
basalts of the plateau. JI at once got into the longboat, and,
favoured by an unusually calm sea, was enabled to steer into every
nook and round every buttress and islet of this part of the coast-line.

The basalt-plateau here presents to the western ocean a nearly
vertical escarpment which must reach a height of at least 1000 feet
(see fig. 24, p. 380), and displays a magnificent section of the bedded
lavas. The lower part of this section shows chiefly the banded
structure already described, the layers of different consistency being
etched out by the weather in such a way as to give them the look of
stratified rocks. In the upper part of the precipice columnar and
jointed or prismatic sheets are more common, but the most pro-
minent band is the great sill just alluded to, and to which further
reference will be made in the sequel.

In the course of the gradual retreat of the cliff, as the waves
tunnel its base and slice after slice is detached from its vertical
front, a group of at least five small vents has been uncovered lying
along a nearly north-and-south line. Of two of these a segment
remains still on the cliff-wall and passes under the basalts; the
others have been dissected and half Git away from the cliff, while
groups of stacks and rocky islets of agglomerate may mark the

344 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

positions of others almost effaced. The horizontal distance within
which the vents are crowded is probably less than half a mile, but
the lofty proportions of the precipice tend to lead the eye to under-
estimate both heights and distances.

The agglomerate is a thoroughly volcanic rock, consisting of blocks
of all sizes of various basalts, among which large slags are specially
conspicuous, the whole being wrapped in a granular matrix of com-
minuted volcanic detritus. The arrangement of this material is best
seen in the fourth vent (Pl. XV. and fig. 8). In this characteristic

Fig. 8.—Section of the same neck as that shown mm Pl. XV.
EH ATMTTHATRRNN in TaTIGATA Wa F
ul ii | | \ | Dalit :
= sire Ly
Pee a Urn CALLE It me

ae 4 ee Satta

ye
ms

volcanic neck (6 in fig. 8) the boundary walls, as laid bare on the
face of the precipice, are vertical, and are formed of the truncated
ends of the banded lavas (aa) which have been blown out at the
time of the formation of the orifice. ‘The visible diameter of the
vent was roughly estimated by me to be about 100 yards. No
appreciable alteration was observed in the ends of the lavas next
the vent. The agglomerate is coarsest in the centre, where huge
blocks of slaggy lava lie imbedded in the amorphous mass of com-
pacted débris. On either side of this structureless central portion
the agglomerate is distinctly stratified from the walls towards the
middle, at angles of 30° to 35°. Even from a distance it can be
observed that the upper limit of the agglomerate is saucer-shaped,
the sloping sides of the depression dipping towards the centre of
the neck at about the same angle as the rudely stratified agglo-
merate underneath. From the bottom of this basin to the sea-level
may be a vertical distance of some 30 yards. The basin itself has
been filled up by three successive flows of basalt, of which the
first has merely overflowed the bottom, the second (d), entering
from the northern rim of th~ basin, extends across to the southern
slope, while the third (e), alS flowing from the north, has filled up
the remainder of the hollow and extended completely across. it.
The next succeeding lava (f) stretched over the site in such a way

Quart. Journ. Geol. Soc. Vol. LII. Pl. XY.

VoLCANIC NECK PIERCING AND OVERLAIN BY THE PLATEAU-BASALTS, STROMO, ENTRANCE OF VAAGOrFJoRD, Faron IsLanps.
(From a photograph by Col. Joun Evans.)

Ee
. °
ar

= 2
= S L o — a i a a Ps
St i Oa mcg a te oan — aged e e ae Na arly ARE Steric PS ml hit oe Nan a Se eS ee yi, oF A a a Sl a peeve nol ene ue

ee ee et ee ee ee

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 345 ©

as to bury it entirely, and to provide a level floor for the piling up
of the succeeding sheets of basalt.

The second vent, which is represented in fig. 9, exhibits the
same features, but with some
additional points of interest.
It measures roughly about 20
yards in diameter at the sea-
level, rises through the same
group of banded basalts (a a),
and is filled with a similar
agglomerate (b). Its more
northerly wall is now coinci-
dent with a line of fault (A)
which ascends the cliff, and
probably marks some subsi-
dence after the eruptions had
ceased. The southern wall
shows that a dyke of basalt (7)
has risen between the agglome-
rate and the banded basalts,
and that a second dyke (g’) tra-
verses the latter at a distance
of a few feet. In this instance, also, the upper surface of the
agglomerate forms a cup-shaped depression which has been filled in
by two successive streams of lava (c,d). Among the succeeding
lavas (¢) a prominent sill (7) has been intruded, to which more
special reference will be made in the sequel.

These necks are obviously volcanic vents belonging to the time of
the basaltic eruptions. They have been drilled through the basalts of
the lower part of the cliff, but have been buried under those of the
central and higher parts. The arrangement of their component
materials in rude beds dipping towards the centre of the vent shows
that the ejected dust and stones must have fallen back into the orifice
so as to be rudely stratified towards the centre of the chimney, which
was finally closed by its own last discharges of coarse detritus. The
saucer-shaped upper limit of the agglomerate seems to indicate that
after the eruptions ceased each vent remained as a hollow or maar
on the surface of the lava-fields. And the manner in which they
are filled with successive sheets of basalt shows that in course of
time other eruptions from neighbouring orifices gave forth streams
of lava which, in flowing over the volcanic fields, eventually buried
and obliterated each of the vents.

In the destruction of the precipice some of the vents have been
so much cut away that only a small part of the wall is left, with
a portion of the agglomerate adhering to it. The third neck, for
instance, affords the section represented in fig. 10, p. 346, where the
horizontal sheets of basalt (a) have still a kind of thick pellicle of
the volcanic detritus (>), adhering to what must have been part of
the side of the orifice of eruption. The waves have cut out a cave
at the base, so that one can, by boat, get behind the agglomerate
and see the margin of the volcanic funnel in the roof overhead.

Fig. 9.— Volcanic neck close to that
shown in Pl. XV. & fig. 8.

346 SIR A. GEIKIE ON THE TERTIARY [May 1896,

In the fragment of geological history so picturesquely laid bare.

on the Stromo cliffs we are presented with a significant illustration
of what seems to have been a common type of volcanic vent in
the Tertiary basalt-plateaux. By the
fortunate accident that denudation has
not proceeded too far, we are able to
observe the original tops of at least two
of the vents, and to see how such
voleanic orifices, which were doubt-
less abundant all over these plateaux,
came to be entombed under the ever-
increasing pile of accumulating basalt.

There is still one feature of interest
in these cliff-sections which deserves
notice here. very geologist who has
studied the composition of the basalt-
plateaux has remarked the compara-
tively insignificant part played by
tuffs in these volcanic accumulations.
Hundreds of feet of successive basalt-
sheets may often be examined without
the discovery of any intercalation of
fragmental materials, and even where
such intercalations do occur they are
for the most part quite thin and extremely local. I found it
impossible to scale the precipice for the purpose of ascertaining
whether around the Stromo vents, and connected with them, there
might not be some beds of tuff interstratified between the basalts.
Tf such beds exist, they can be of only trifling thickness and extent.
Here, then, are examples of once active vents, the funnels of which
are still choked up with coarse fragmentary ejections, yet from
which little or no discharge of ashes and stones took place over the
surrounding ground. They seem to have been left as maare or
erater-like hollows on the surface of the lava-fields.

' The next example of a neck which I will describe occurs on the

cliffs that form the southern side of the sheltered inlet known as
Portree Bay in the Isle of Skye. These cliffs, the seaward escarpment
of the basalt-plateau, rise above a platform of Jurassic sandstones
and shales. At Camas Garbh, where they have been trenched by
a small rivulet, aided by the presence of two dykes, the gully thus
formed exposes a section of a neck of agglomerate that underlies
the basalts of the upper half of the cliff. This neck is connected
with a thick deposit of volcanic conglomerate and tuff which, lying
between the basalts, extends from the neck to a considerable
distance. The general relations of the rocks in this cliff are
represented in fig. 11.

The agglomerate (6 in fig. 11) is quite tumultuous, and here
and there strikingly coarse. Some of its included blocks measure
5 feet in length. These fragments represent most of the varieties
of the lavas of the district. Large slaggy masses are abundant,

Fig. 10.—Section of wall
of another neck of agglo-
merate in the same group
with those represented in

PI. XV. & fags. 8, 9.

and sometimes exhibit the annelid-like elongation of the vesicles.

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 347

to which I have referred as occasionally displayed by the plateau-
basalts. More than 60 feet of agglomerate is visible in vertical
height from where its base is concealed by débris and vegetation to
where its upper surface passes under a banded rock to be afterwards
described. That this unstratified mass of volcanic ejectamenta marks
the site of the vent can hardly be doubted, although denudation
has not revealed the actual walls of the chimney. The steep
grassy slopes do not permit of the relations of the rocks being every-
where seen, but the agglomerate appears to pass laterally into
finer, rudely stratified material of a similar kind, which extends
east and west of the vent as a thick deposit between the bedded

Fig. 11.—Section of volcanic vent and connected lavas and tuffs.
Scorr, Camas Garbh, Portree Bay, Skye.

= ae sie oy “a, <7 «
Gia me,

_" ‘s 7K»

a. Rudely-bedded dull green tuff ; 6. Coarse agglomerate ; c. Prismatic basalt ;
d, Massive jointed basalt; ¢. Red banded decomposing rock, probably of
detrital origin; f. Plateau-basalts, prismatic and rudely columnar ; g. Dyke
of dolerite, somewhat vesicular, 5 to 6 feet broad ; h. Basalt dyke 2 to 3 feet
broad; 7. Dyke or sill of basalt similar to h, and possibly connected
with it. 4,

basalts. Possibly denudation has only advanced far enough to lay
bare the crater and its surrounding sheets of fragmentary material,
while the chimney lies still buried underneath.

East of the agglomerate the fragmentary material becomes less
coarse, and shows increasing indications of a bedded arrange-
ment. Close to the agglomerate the dip of the coarse tuff is
towards that rock at about 10°. A few yards farther east a
sheet of very slaggy basalt is seen to lie against the tuff, which it
does not pierce. The vesicles in this adhering cake of lava have
been pulled out in the direction of the slope till they have be-
come narrow tubes 4 or 5 inches long and parallel to each other.
Some parts of this rock have a curved ropy surface, like that of
well-known Vesuvian lavas, suggestive of the molten rock having
flowed in successive thin viscous sheets down the slope, which has
a declivity of about 30°. This part of the section may possibly
preserve a fragment of the actual inner slope of the crater, formed
of rudely bedded tuffs.

348 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

Continuing still eastward, we find the feebly stratified tuff (a) to
be perhaps 200 feet thick. It forms a grassy declivity that descends.
from the basalt-escarpment above to the grass-covered platform
whieh overlies a lower group of basalts. The visible portion of
this tuff presents a thoroughly volcanic character, being made up of
the usual dull dirty-green granular paste, through which are
dispersed angular and rough lumps of slag and pieces of more solid.
basalt varying up to 1 or 2 feet in length. These stones are
generally disposed parallel to the indistinct bedding, but are some-
times placed on end as if they had assumed that position on falling
from an explosive shower. Among the smaller stones, pieces of a
finely vesicular basic pumice are frequent and are among the most
strikingly volcanic products of the deposit. From a characteristic
sample of these stones, a thin slice was prepared and placed in
_ Mr. Harker’s hands. The following are his observations on it :—
‘A very compact dark-grey rock, amygdaloidal on a minute scale.
The lighter grey crust is probably due merely to weathering, and
the specimen seems to be a distinct fragment, not a true bomb.

‘The slice [6662] shows it to be essentially a brown glass with
only occasional microscopic crystals of a basic plagioclase. It has
‘ been highly vesicular, and the vesicles are now filled by various
secondary products, including a chloritic mineral, nearly colourless.
and singly refracting in thin section, and a zeolite.’

Tracing now the tuff from the western side of the vent, we can
follow it to a greater distance. No abrupt line can be detected
here, any more than on the other side between the agglomerate and.
the tuff. The latter rock extends under the overlying plateau of
basalt, at least as far west as Portree Loch, a distance of fully a
mile, but rapidly diminishes in thickness in that direction. Traces
of what is probably the same tuff can be detected between the
basalts at Ach na Hannait, more than 3 miles to the south. It
is thus probable that from the Portree vent fragmentary discharges
took place over an area of several square miles.

Above the agglomerate of this vent two lavas may be seen to
start towards opposite directions. One of these (¢ in fig. 11)
begins immediately to the east of the two dykes. It is a dull
prismatic basalt with a slaggy bottom, its vesicles being pulled out
in the direction of the general bedding of the section. It descends
by a twist or step, and then lies on the gently inclined surface of
the tuff which dips towards the agglomerate. Farther east it
increases in thickness and forms the lowest of the basalt-sheets of
the cliff. The lava that commences on the western side of the vent
(d in fig. 11) is a massive jointed basalt, which, though not seen at
the vent, appears immediately to the west of it and rapidly swells.
out so as to become one of the thickest sheets of the locality. It
lies upon the rudely bedded tuff, and is covered by the other basalts:
of the cliff.

That these two basalts came out of this vent cannot be affirmed.
If they did so at different times, their emission must have been
followed by the eruption which cleared the funnel and left the

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE, 349

central mass of agglomerate there. But that some kind of saucer-
shaped depression was still left above the site of the vent is indicated
by the curious elliptical mass of rock (¢) that lies immediately
above the agglomerate from which it is sharply marked off. This
is one of the most puzzling rocks in the district, probably in large
measure owing to its advanced state of decay. It is dull red in
colour and decomposes into roughly parallel layers, so that at a
short distance it looks like a bedded tuff, or like some of the
crumbling varieties of banded lavas. I could not obtain specimens
fresh enough to put its nature and origin beyond dispute. What-
ever may have been its history, this ferruginous rock rests in a
saucer-shaped depression lying directly above the agglomerate of
the vent. The form of this depression, like that of the Faroe
necks, corresponds fairly well with what we may suppose to have
been the final position and shape of the crater of the little volcano.
The rock that occupies the hollow dies out towards the east on the
face of the cliff, and the prismatic basalt (c) is then immediately
covered by the rest of the basalt-sheets of the plateau (f). On the
western side its precise termination is concealed by grass. But it
must rapidly dwindle in that direction also, for not many yards away
it is found to have disappeared, and the basalts (d and f) come
together.

Though the decayed state of this rock does not warrant any very
confident opinion regarding its history, I am inclined to look upon
it as a deposit of much disintegrated volcanic detritus washed into
the hollow of the old crater when it had become filled with water,
and had passed into the condition of a maar. The peculiarly
oxidized condition of its materials points probably to long atmospheric
exposure, and an examination of the surrounding parts of the
district furnishes more or less distinct evidence that a considerable
lapse of time did actually intervene between the cessation of the
eruptions of the Portree volcano and the next great basalt-floods of
this part of Skye.

That volcanic eruptions from other vents continued after this
Portree example had become extinct is proved by the great sheets
of basalt (f) that overspread it and still bury a large tract of the
fragmentary material which it discharged. Ata later time a fissure
that was opened across the vent allowed the uprise of a basalt dyke
(g), and subsequently another injection of similar material took place
along the same line of weakness (/ and 7).

Before leaving this interesting locality we may briefly take note
of the distribution of the ashes and stones ejected by the volcano,
and the evidence for the relative length of the interval between the
outflow of the lavas below and that of those above the tuff and
volcanic conglomerate. Admirable sections of these deposits may
be traced along the base of the cliffs for a mile to the west of the
vent. They thin away so rapidly in that direction that at a
distance of ? mile they do not much exceed 50 feet in thickness.
At Camas Ban they consist mainly of a fine, dull-green, granular,
rudely stratified basalt-tuff, through which occasional angular

300 . SIR A. GEIKIE ON THE TERTIARY [May 1896,

pieces of different lavas and rough slags are irregularly dispersed.
These stones occur here and there in rows, suggestive of more
vigorous discharges, the layers between the platforms of coarser
detritus being occupied by fine tuff. Some of the ejected blocks are
imbedded on end—an indication of the force with which they were
projected and fell nearly a mile from the crater.

The upper parts of the tuff pass upward into fine yellow, brown,
and black clays a few feet in thickness, the darker layers being full
of carbonaceous streaks. On this horizon the coal of Portree was
formerly mined. The workings, however, have long been abandoned,
and, owing to the fall of large blocks from the basalt-cliff overhead,
the entrance to the mine is almost completely blocked up. One
wooden prop may still be seen keeping up the roof of the arch,
which is here a slaggy basalt. .

East and south-east of the Portree vent, extensive landslips of
the volcanic series and of the underlying Jurassic formations
make it hardly possible to trace the continuation of the tuff-zone
in that direction. To the south, however, at a distance of rather
more than 3 miles, what is probably the same stratigraphical
horizon may be conveniently examined from Ach na Hannait for
some way to the north of Tianavaig Bay. At the former locality
the calcareous sandstones of the Inferior Oolite are unconformably
covered by the section represented in fig. 12. At the bottom of
the volcanic series lies a sheet of
nodular dolerite with a slaggy upper Fig. 12.—Section of the

surface (a). Wrapping round the pro- volcanie series at Ach na
jections and filling up the depressions Hannait, south of Portree,
of this lava comes a thin group of Skye.

sedimentary strata from 1 or 2 to
18 inches or more in thickness (6).
These deposits consist of hardened
shale charged with macerated remains
of linear leaves and other plant-
remains, including and passing into
streaks of coal, which may be looked
upon as probably occupying the same
horizon with the coal of Portree. But
here, instead of reposing on a mass of
stratified tuff, the carbonaceous layers
lie on one of the bedded lavas. The
tuff has died out in the intervening
3 miles, yet that some of the dis-
charges of volcanic detritus reached
even to this distance, and that they took place during the accumu-
lation of these layers of mud and vegetation is shown by the
occurrence in the shales of pieces of finely amygdaloidal basalt
from less than 1 to 6 inches in length, likewise of lapilli of a
fine, minutely cellular, basic pumice, like some varieties of pala-_
gonite. The overlying dolerite (c) becomes finely prismatic at its

(‘enuey jo ‘wony, sstpq Aq yderSoj0yd & wo1q) (‘eT “8g osTe 99g) ©

; “YNNV/) dO GNVISI SHEL dO GNA NUALSVA AAT LY MOMN OINVOTOA V JO LUV

TAX Id IT'D TOA O§ “1099 “Urnof “qaeng)

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. B51

junction with the sedimentary layers, and has probably indurated
them.

This intercalation of a shaly and coaly band among the lavas
can be followed northward along the coast. In some places it has
been invaded by dykes, sills, and threads of basalt on the most
remarkably minute scale, of which I shall give some account in a
later part of this paper (see fig. 21, p. 375). North of Tianavaig
Bay—that is, about ? mile nearer to the Portree vent—a _ per-
ceptible increase in the amount of volcanic material is observable
among the shales and leaf-beds. Not only are lapilli of basic
pumice abundant, but the volcanic detritus has accumulated here
and there in sufficient amount to form a band of dull greenish-
brown tuff.

I have already alluded to the characteristic fact that the inter-
stratifications of sedimentary material among the basalt-plateaux
frequently terminate upward in leaf-beds, thin coals, or layers of
shale, full of indistinctly preserved remains of plants, and some
further striking illustrations of this feature will be described from
the river-shingles and other evidences of water-action during the
volcanic period in the islands of Canna and Sanday. There cannot
be any doubt that the vegetation thus preserved was terrestrial.
It probably grew not far from the sites where its remains have
been preserved. Leaves and seeds would naturally be blown or
washed into pools on the lava-fields, and would gather there among
the mud and sand carried by rain from the surrounding ground.
Such a topography and such a sequence of events point to intervals
of longer or shorter duration between the successive outpourings of
basalt. It was probably during one of these intervals of quietude
that the crater of the Portree voleano became a maar, and was
finally silted up.

There is one last example of a volcanic vent, of which a description
mayhere be given. It occurs at the eastern end of the island of Canna.
A portion of it projects from the grassy slopes, and rises vertically
above the beach as a picturesque crag in front of the precipice of
Compass Hill (Pl. XVI.). But the same rock may be traced south-
ward to the Coroghon Mor, and north-westward in the lower part
of the cliffs to a little beyond the sea-stack of An Stoll. It has
thus a diameter of at least 3000 feet. Westward it passes under the
conglomerate to be afterwards described, and its eastern extension
has been concealed by the sea.

The materials that fill this vent consist of a typical agglomerate
composed entirely, or almost entirely, of volcanic detritus. The
imbedded blocks vary up to 8 feet in diameter or even more.
They are chiefly fragments of various basalts and andesites, generally
vesicular or amygdaloidal. Some of these, which have evidently
been broken off already consolidated lavas, are angular or sub-
angular in shape, and their steam-holes are cut across by the outer
surfaces of the stones. Where filled with calcite, zeolite, etic., the
amygdules so exactly resemble those of the bedded basalts of the

302 SIR A. GEIKIE ON THE TERTIARY [May 1396,

plateaux that, as already remarked, we must believe them to have
been already filled by infiltration before the disruption of the rocks
by volcanic explosions. Other blocks are true bombs, with a fine-
grained crust outside and a more cellular texture inside, the vesicles
of the outer crust being sometimes dragged round the surface
of the stone. The variety of materials included among the ejected
blocks and the abundance of pieces of the red bole which so
generally separates the plateau-basalts indicate that a considerable
thickness of bedded lavas has probably been broken through by the
vent. Besides the volcanic materials, occasional angular pieces of
red (Torridon) sandstone may be observed in the agglomerate.
The paste is a comminuted mass of the same material as the
blocks, tolerably compact, and entirely without any trace of strati-
fication.

The actual margin of this vent has nowhere been detected by me.
We never reach here the base of the volcanic series, for it is sunk
under the sea-level. On the other hand, the upper limits of the
agelomerate have been partially effaced or obscured by the thick
conglomerates which overlie it. There can be no doubt, from the
breadth of ground across which the agglomerate can be followed
along the shore, that the vent must have been one of somewhat
exceptional size, perhaps not less than # mile in diameter, unless,
indeed, there were more than one in close proximity. That
it continued in vigorous eruption may be judged from the amount
of material ejected from it, the large size of its blocks, and the
distance to which they were sometimes thrown.

The pieces of Torridon Sandstone were no doubt derived from the
extension of that formation underneath Canna. On the opposite island
of Rum these pre-Cambrian red sandstones are copiously developed.
They form there a platform through which the Tertiary volcanic
series has been erupted. Several remaining outliers of the bedded
basalts on thewestern side of that island show that the basalt-plateau
of Small Isles once covered that area, and that it rested imme-
diately on the inclined edges of the Torridon Sandstone. Probably
the same structure stretches westward under Canna and Sanday.
No traces of any Jurassic strata have been detected beneath the
voleanic rocks of Rum, though they are so well developed a few
miles to the east in the island of Kigg. Hither they were not
deposited over the pre-Cambrian rocks of Rum, or they had been
removed from that ancient ridge before the beginning of the
Tertiary volcanic period. Certainly I have not detected a single
recognizable fragment of any Jurassic sedimentary rock in the
agglomerate of Canna.

This Canna vent exhibits, better than is usually shown, the
occurrence of dykes and irregular injections of lava through the
agglomerate. A large mass of a finely columnar basalt ascends
from the beach at Garbh Asgarnish. A similar rock forms several
detached crags a little farther south, particularly in the headland
of Coroghon Mor and the island of Alman. Here the basalt is

‘Vol. 52.] §BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 353

beautifully columnar, its slender prisms curving from a central line
until their ends abut against the agglomerate. The truly intrusive
character of this basalt is

well shown on the southern Fig. 13.—Columnar basalt invading
front of Coroghon Mor, and = agglomerate of volcanic vent. Coro-
on the northern face of ghon Mor, Isle of Canna. (Height
Alman, as represented in more than 20 feet.)

the accompanying diagrams
(figs. 13 & 14).

Although there is no
conclusive evidence that
these intrusions belong to
the time of the activity of
the vent, yet they differ
so much from the ordinary
dykes (one of which also
cuts the agglomerate and
ascends through the con-
glomerates and basalts
above), are confined so
markedly to the vent and
its immediate proximity,
and resemble so closely the
basalt-injections of other vents, such as those of the Carboniferous
and Permian necks of Scotland, that they may with every proba-
bility be regarded as part of the mechanism of the Canna volcano.

Though the form
and size of the vent Fig. 14—Coluwmnar basalt invading vol-
of this volcano cannot canic conglomerate. Northern side of
be precisely defined, Alman Islet, Canna.
the upper part of its
agglomerate is dove-
tailed in the most
interesting way with
a series of coarse con-
glomerates, which
indicate strong
aqueous action in this
part of the volcanic
area during the time
of the eruption of the
plateau-basalts. As
the history of the
eruptions of the Canna °
vent is so closely linked ‘2.
with that of some
powerful river which flowed across the lava-fields in this part of
Western Scotland, I reserve further account of it for the next
section of this paper.

304 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

Ill. Tue Rivers oF tae Vortcanic Prriop.

Many years ago I communicated to this Society an account of an
ancient river-channel which, during the voleanic period, had been
eroded on the surface of the basalt-plateau, and of which a small
portion had been preserved under a stream of pitchstone-lava that
had flowed into and buried it. This watercourse, now marked
by the picturesque ridge of the Scuir of Eigg, was shown to have
been excavated by a stream which came from the north-east or
east, and to be younger, not only than the plateau-basalts of the
district, but younger even than the dykes which cut these basalts.
Yet that it belonged to the volcanic period was proved by the
manner in which it had been sealed up and preserved under the
black glassy lava of the Scuir.

Within the last two years I have met with other and more
abundant evidence of river-action in the same region of the Inner
Hebrides. This evidence, however, belongs to an earlier part of
the volcanic period. It reveals that a powerful river, flowing west-
ward from the Highland mountains, swept over the volcanic plain,
while the sheets of basalt were still being poured forth, and while
volcanic eruptions were taking place from cones of slag.

This interesting record is preserved in the islands of Canna and
Sanday. The gravels and silts of the river are there found inter-
calated between the basalts, mingled with volcanic detritus, probably
ejected from the active vent already described. On visiting these
islands for the first time last year, I found so much that was new
to me in regard to the history of Tertiary volcanic action, and
which demanded a careful survey, that I returned to the locality
this summer and remained in Canna until I had mapped that
island and its dependencies upon the Ordnance Survey sheets on
the scale of 6 inches to a mile.

Macculloch, in his account of Canna and Sanday, took notice of
the intercalation of beds of conglomerate among the basalts. He
regarded these detrital rocks as having been arranged under water
and as marking pauses in the deposition of the sheets of ‘trap.’
He likewise gave two diagrams in illustration of the relations of
the conglomerates, but he expressed no definite opinion as to the
origin of these rocks, though in one passage he seems to have
inclined towards the belief that they were formed in the sea,”
Since his time, so far as Lam aware, no fresh light has been thrown
upon the subject.

The conglomerates are best developed at the eastern end of
Canna, where the cliffs present the structure illustrated in fig. 15.
At the base, and passing under the level of the sea, lies the agglo-~
merate (a) of the vent already described. This rock has a some-
what uneven upper surface, which rises in places about 150 feet
above high-tide mark. Here and there it shades off upward into

1 Quart. Journ. Geol. Soc. vol. xxvii. (1871) p. 303.
2 «Description of the Western Islands,’ vol. 1. (1819) pp. 449, 457, pl. xix.

figs. 2 & 3.

Vol. 52.] BASALI-PLATEAUX OF NORTH-WESTERN EUROPE. 305

the conglomerate that overlies it; waterworn pebbles appear
among its contents, and rude traces of bedding begin to show them-
selves, until, within the course of a few feet, we pass upward into
an undoubted conglomerate. Elsewhere, however, and particularly
along the precipices west of Compass Hill, the two deposits are

Fig. 15.—Section of the chffs below Compass Hill,
Isle of Canna.

[AW
i ( i)

more distinctly marked off from each other. The agglomerate has
there a hummocky, irregular upper surface, as if it had been thrown
down in heaps. The hollows between these protuberances have
been filled up with conglomerate and sandstone, forming the base
of the thick overlying deposits.

Q.J.G.8. No, 206. 2B

356 SIR A. GEIKIE ON THE TERTIARY [May 1896,

It is thus clear that the loose materials of the vent were directly
exposed at the surface when the conglomerate was accumulated,
and, indeed, that these materials served to supply some of the
detritus of which the conglomerate consists. The absence of any
trace of a cone and crater at the vent may perhaps be explicable on
the supposition that their incoherent material was washed down by
the currents that swept along and deposited the conglomerate.

The mass of sedimentary material (6) which overlies the ag-
glomerate of the vent forms a conspicuous feature along the lower
half of the precipices at the eastern end of Canna. It rises to a
height of 250 to 300 feet above sea-level, and must reach a
maximum thickness of probably not less than 100 to 150 feet. It
gradually descends in a westerly direction both along the northern
cliffs and in the lower ground round Canna Harbour, insomuch
that in about a mile, owing to the gentle westerly dip of the whole
volcanic series, combined with the effect of a number of small
faults, it passes under the level of the sea.

Great variation in the character of the detritus composing this thick
group of strata may be observed as it is followed westward. On the
cliffs below Compass Hill, as represented in fig. 15, p. 355, a coarse
conglomerate with waterworn stones, hardly to be distinguished
from the volcanic agglomerate of the vent, shows more or less
distinct bedding, or at least a succession of coarser and finer bands.
Towards its base it encloses numerous pieces of Torridon Sandstone,
sometimes subangular, but often so well and smoothly rounded as
to show that they must have been long subjected to the action of
moving water. It is further observable that, while in the agglo-
merate the volcanic stones have rough surfaces, those in the
conglomerate begin to show increasing evidence of attrition, until,
as the deposit is traced upward, they become almost as well rounded
and waterworn as the non-volcanic stones which have come from
another district.

Yet amidst and overlying these proofs of transport from some
little distance lie abundant huge slags and blocks of amygdaloidal
lava, sometimes closely aggregated, sometimes scattered through
a voleanic tuff or ashy sandstone. The composition and structure
of these stones, and the manner of their dispersion through the
deposit, leave little doubt that they were ejected from the vent.
We are thus confronted with the interesting fact that, while the
materials of the volcanic cone were being washed down by running
water, eruptions were still taking place. But by degrees these indi-
cations of contemporaneous volcanic activity disappear. The detrital
materials become coarser and more distinctly water-rolled, until they
pass into greenish sandstones and fine conglomerates. Yet the
matrix even of these higher sediments is largely composed of fine
voleanic detritus, and probably points to occasional discharges of
dust and ashes. |

Various sills or intrusive sheets have been injected into this sedi-
mentary group along the precipices at the eastern end of Canna, and
form there lenticular bands. One of these (c) is stown in fig. 15.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 357

Immediately above the massive greenish pebbly sandstone (d)
which caps the stratified series, lies a group of basalts (e), composed
of several distinct beds, having a united thickness of from 80 to
100 feet. The lowest of these has a regular columnar structure,
while those overlying it exhibit the confused starch-like grouping of
curved and rather indistinctly-formed prisms, which is so cha-
racteristic a structure in the plateaux.

The next band in upward succession is one of conglomerate (/),
which runs as a continuous and conspicuous feature along the upper
part of the cliff. This rock presents in many respects a strong
contrast to the conglomerates underneath. It is dull green to
yellow in colour, and is well stratified, being marked by the inter-
stratification of finer layers, and passing down into a band of
pebbly sandstone, which rests immediately on the basalt (e). Its
component stones are thoroughly waterworn, ranging up to 6

inches or even more in length. But its most distinctive character
lies in the nature of its pebbles. Instead of consisting mainly of
volcanic materials, these stones have almost all been transported for
some distance. They include abundant fragments of Torridon
Sandstone, gneiss, schists, grits, and other rocks like those in Rum
and Western Inverness-shire. No such rocks exist in situ in Canna.
The nearest tract of Torridon Sandstone is in Rum, about 4 miles to
the eastward. But the pieces of schist and epidotic grit, like the rocks
of the Western Highlands, must have travelled at least 30 miles.

It is important to observe that all these transported stones
indicate a derivation from some source lying to the eastward of
Canna. The evidence in this respect agrees with that furnished by
the ancient river-gravel under the pitchstone of the Scuir of Eigg.
It is clear that the waters which found their way across the lava-
fields of this part of the Inner Hebrides took their rise among the
mountains of Inverness-shire.

The conglomerate now described is from 40 to 50 feet thick. It
can be followed along the face of the cliffs for more than a mile on
the northern side of Canna. Less persistent on the southern side, its
outcrop strikes from the edge of the precipice inland, keeping to
the south of the top of Compass Hill. It is well seen in the ravine
above the Coroghon, but cannot be followed farther westward
among the basalt-terraces. Yet, though this stratified intercalation
is not traceable very far as a band of conglomerate, the same strati-
graphical horizon is probably indicated elsewhere by other kinds
of sedimentary deposits, to which further reference will be made in
the sequel.

The section now described establishes the existence of at least
two successive platforms of conglomerate in the volcanic series.
Following these platforms along their outcrop, we obtain additional
light on their origin, and on the topographical conditions under
which they were deposited, and we learn further that other pro-
longed intervals, which were likewise marked by intercalations of
sedimentary material, occurred in the outpouring of the basalts.

Taking first the lower conglomerate of Compass Hill and tracing

2B2

358 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

it westward, we find that it forms the depression in which the
sheltered inlet of Canna Harbour lies. It is exposed along the
shores and also in the islands enclosed within the same bay. But
it is not traceable farther west, possibly because it seems to sink
beneath the level of the sea. To the south-east, though it is there
likewise tor the greater part concealed under the waves, it rises above
them in one or two parts of the coast-line of Sanday, particularly
at the Uamh Ruadh or Red Cave, and likewise on a surf-beaten
skerry off Ceann an Eilein, the highest part of the Sanday cliffs—a.
distance of about 14 mile from Compass Hill. Throughout this.
space it retains its remarkably coarse character, and is mainly made
up of volcanic material.

The numerous sections exposed in Canna Harbour enable us to
study the composition and local variations of this curious deposit..
On the northern side of the basin, while the lower part of the
sedimentary series continues to be an exceedingly coarse volcanic
conglomerate, it passes upward into finer conglomerates, tuffs, and.
shales. In front of Canna House the imbedded blocks are of large
size, occasionally as much as 3 or 4 feet in diameter. They are
still more gigantic on Eilean a’ Bhaird, where I found one to
contain 150 cubic feet in the exposed part, the rest being still
imbedded in the matrix. As they are generally somewhat rounded,
here and there markedly so, most of these stones have probably
undergone a certain amount of attrition in water. The great
majority of them, and certainly all those of larger size, are pieces:
of basalt, dolerite, andesite, red bole, etc. Among them huge
blocks of amygdaloid and coarsely vesicular lava are specially
abundant. Some of these look like pieces of slag torn from the
upper surface of lava-streams ; others, displaying a highly vesicular
centre and a close-grained outer crust, are suggestive of bombs.
It is interesting to note here again that the amygdaloidal blocks.
present their zeolitic infiltrations so precisely like those of the
amygdaloids of the plateaux, that it seems reasonable to suppose
the carbonate of lime, zeolites, etc. to have been introduced before
the blocks were imbedded in the conglomerate.

The whole aspect of this deposit is eminently volcanic. It looks.
like a vast sheet of lava-fragments swept away from one or more
cones of slags and cinders, or from the rugged surface of a lava-
stream. Where the vesicles were still empty, the large boulders
could be more easily swept along by moving water. Buta powerful
current must have been needed to transport and wear down into:
more or less rounded forms blocks of basic lava, many of which
must weigh several tons. The large block on Eilean a’ Bhaird,
for instance, probably exceeds 12 tons in weight.

Besides the obviously volcanic contents of the conglomerate there
occur here also, as in the Compass Hill cliffs, abundant pieces of
Torridon Sandstone. These stones are notably smaller in size and
more perfectly waterworn and even polished than the blocks of
lava. Obviously they have travelled farther and have undergone
more prolonged attrition.

The matrix of the rock consists essentially of the fine detritus of

Vol. 52.] BASALI-PLATEAUX OF NORTH-WESTERN EUROPE. 309

basic lavas, probably mingled with true volcanic dust. The coarser
parts display only the feeblest indication of stratification ; indeed,
in a limited exposure the rock might be regarded as a tumultuous
agglomerate. But the manner in which the deposit is intercalated
with, and sometimes overlies, green tuffs and shales, together with
the waterworn condition of its stones, shows that it has not been
accumulated in a volcanic chimney, but has been thrown down by
some powerful body of water, with probably the co-operation of
volcanic discharges.

While the composition of the conglomerate suffices to indicate
that it was accumulated at a time when some volcano was active
in the immediate neighbourhood, singularly convincing proofs of the
work of this vent are to be seen in the form of intercalated sheets
of lava. Thus on Eilean a’ Bhaird the boulders of the conglomerate
are overlain and wrapped round by a sheet of rudely prismatic
basalt, with lines of vesicles arranged in the direction of the
bedding. A similar relation can be traced along the beach between
Canna House and the wooden pier, where successive sheets of basalt
have flowed over the conglomerate (see fig. 16, p. 361).

But, besides coarse voleanic detritus, the sedimentary platform
represented by the lower conglomerate of Compass Hill includes
other deposits of which good sections may be examined all round
Canna Harbour. Beds of fine, well-stratified, dull green tuff pass by
an admixture of pebbles into fine ashy conglomerate or pebbly sand-
stone, and by an increase in the proportion of their fine detritus
into voleanic mudstone and fine shales. The shales vary from a
pale grey or white tone into blackish grey, brown, and black.
They are well stratified and are frequently interleaved with layers
of fine tuff. The darker bands are carbonaceous, and are not in-
frequently full of ill-preserved vegetation. Indeed, leaves and stems
in a rather macerated condition are of common occurrence in all the
shaly layers. Here and there, especially in some ashy shales in
front of Canna House, I observed a recognizable Sequoia. The
mudstones are dull green, close-grained, shattery rocks composed of
fine volcanic detritus, and pass both laterally and vertically into
shales, tuffs, and conglomerates. They suggest showers of fine
dust or streams of volcanic mud. They, too, contain fragmentary
plants.

It is a noteworthy fact, to which reference has already been made,
that the sedimentary intercalations among the Canna basalts gener-
ally end upward in carbonaceous shales or coaly layers. The strong
currents and overflows of water, which rolled and spread out the
coarse materials of the conglomerates, gave way to quieter conditions
that allowed silt and mud to gather over the water-bottom, while
leaves and other fragments of vegetation were blown or washed
into these quiet reaches. Good illustrations of this sequence in the
ease of the lower conglomerate-zone of Canna may be studied along
the shores of Sanday, from the Catholic Chapel eastward. The
fine pebbly sandstones, tuffs, and shales, which there overlie the
coarse conglomerate, are surmounted by dark brown or black
carbonaceous shale with lenticles of matted vegetation that pass

360 SIR A. GHIKIE ON THE TERTIARY [May 1896,

into impure coal. Immediately overlying this coaly layer lies a.
sheet of prismatic vesicular basalt, followed by another with an
exceedingly slaggy texture.

Lenticles of shale and mudstone likewise occur in the heart of
the finer parts of the conglomerate, especially towards the top, as
may be seen in the section exposed beneath the basalt behind the
first cottage west from Canna House. One of the most interesting
layers in this section is a seam of tuff varying up to about 2
inches in thickness, which lies at the top of the lenticular band of
tuffs and shales, and immediately beneath the band of basalt-
conglomerate, on which a basalt, carrying a vesicular band near its
bottom, rests. Traced laterally, the dark brown tuff of this seam.
gradually passes into a series of rounded bodies and flattened shells
composed of a colourless mineral which has evidently been developed
wm situ after the deposition of the tuff. Mr. Harker’s notes on thin.
slices made from this band are as follows :—

‘This is a rusty brown, dull-looking rock, rather soft and seemingly
light, but too absorbent to permit of its specific gravity being tested.
The dark brown mass is in great part studded with little spheroidal
bodies, =, to =}, inch in diameter, of paler colour, but the larger ones
having a dark nucleus. In other parts larger flat bodies have been
formed, as if by the coalescence of the spheroids, extending as
inconstant bands in the direction of lamination for perhaps 3 inch,
with a thickness of ;4, inch or less. The appearance is that of a
spherulitic rather than an oolitic structure.

‘A slice [6658 4] shows the general mass of the rock to be of am
extremely finely divided but coherent substance of brown colour,
which can scarcely be other than a fine volcanic dust composed of
minute particles of basic glass or ‘ palagonite’ compacted together.
Scattered through this are fragments of crystals recognizable as
triclinic and perhaps monoclinic felspar, green hornblende, augite,
olivine (?), and magnetite, usually quite fresh.

‘The curious spheroidal and elongated growths already mentioned
are better seen in another slide [66538], where they occupy the
larger part of the field, leaving only an interstitial framework of
the brown matrix. The substance of the little spheroids is clear,
colourless, and apparently structureless. The centre is often occu-
pied by an irregularly stellate patch of brown colour, and sometimes
cracks tend to run in radiating fashion, but these are the only
indications of radial structure. The outer boundary is sharply
defined, and where the slice is shattered the spheroids have separated
from the matrix. The matrix is darker than in the normal rock,
being obscured by iron oxide which we may conceive as having beem
expelled from the spaces occupied by the spheroids. The little
cerystal-fragments are enclosed in the spheroids as well as in the
matrix, but there is no appearance of their having served as starting-
points for radiate growths. The flat elongated bodies are like the
spheroids, with merely the modifications implied in their different
shape.

‘The identity of the clear colourless substance seems to be rather

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 361

doubtful. It is sensibly isotropic, and of refractive power distinctly
lower than that of felspar. These characters would agree with
analcime, which is not unknown as a contact-mineral; but it is
difficult to understand how analcime, even a lime-bearing variety
like that of Plas Newydd,* could be formed in abundance from
palagonitic material. An alternative supposition, perhaps more
probable, is that the clear substance is a glass, modified from its
former nature especially by the expulsion of the iron oxide into
the remaining matrix. A comparison is at once suggested with
certain types of ‘ knotenschiefer,’ but respecting the thermal meta-
morphism of fine volcanic tuffs there seems to be little or no direct
information.’

Lenticular interstratifications of shale and mudstone make their
appearance even in the coarser parts of the conglomerate, as may be
observed on the
beachbelow Canna = Fig. 16.—Lava cutting out conglomerate and
House where, as shale. Shore below Canna House.
shown in fig. 16,
some shales and
tuffs full of ill-
defined leaves are
surmounted by a
coarse conglome-
rate. The deposi-
tion of this over-
lying bed of
boulders has given
rise to some scoop-
ing-out of the finer
strata underneath.
Subsequently both the conglomerate and the shales have been over-
spread by a stream of dolerite, the slaggy bottom of which has
ploughed its way through them.

Before discussing the probable conditions under which the group
of sedimentary deposits now described was formed, we may con-
veniently follow the upper conglomerate-band of Compass Hill and
note the variations in structure and composition which its out-
crop presents.

This yellowish conglomerate can be traced along the cliffs for
more than a mile, when it descends below the sea-level at the
solitary stack of Bod an Stol.. A few hundred yards farther west,
what is probably the same band appears again at the base of the
precipice overlain by prismatic basalts. But the conglomerate, here
only 12 feet thick, is made of much finer detritus which, largely
composed of volcanic material, includes small, well-rounded and
polished pebbles of Torridon Sandstone. Beneath it lies a bed of

1 Henslow, Trans. Camb. Phil. Soc. vol. i. (1822) p. 408; Harker, Geol.
Mag. 1887, p.414. Mr. W. W. Watts suggests a comparison with the hexagonal
bodies figured by Mr. Monckton in an altered limestone from Stirlingshire,
Quart. Journ. Geol. Soc, vol li. (1895) p. 488.

362 SIR A, GEIKIE ON THE TERTIARY [May 1896,

dark shale, with remains of plants, resting immediately on a zeolitic ©
amygdaloid which plunges into the sea. The chief interest of this
locality is to be found in the shale which, instead of appearing at
the top of the sedimentary stratification, lies at the bottom. Iwas
informed by Mr. A. Thom that leaves had been cbtained from this
shale, but I was not successful in my search for them. The locality
is only accessible by boat, and, as the coast is fully exposed to the
Atlantic swell, landing at the place is usually difficult and often
impossible.

About 14 mile still farther west, where a foreshore fronts the
precipice of Earnagream at the Camas Tharbernish, a band of
intercalated sedimentary material underlies the great escarpment
of basalts and rests upon the slaggy sheet with the singular ‘aa’
surface already referred to. This band not improbably occupies the
same platform as the upper conglomerate of Compass Hill. It is
only about 7 feet thick, the lower 4 feet consisting of a dull green
pebbly tuff or ashy sandstone, with small rounded pieces of Torridon
Sandstone, while the upper 3 feet are formed of dark shale with
crowded but indistinct remains of plants. Here the more usual
order in the sequence of deposition is restored. The shale is in-
durated and shattery, so that no slabs can be extracted without the
use of quarrying-tools.

Rather less than 4 mile towards the south, on the roadside at
the gully of Cul nam Marbh, the basalts enclose a sedimentary
interstratification which not improbably lies on the same horizon as
those just described along the northern shore. The relations of the
rocks at this locality are shown in fig. 17. A remarkably slaggy
basalt (a) rises into a
hummock against which Fig. 17.—Section of shales, tuffs, and a
have been deposited some coniferous stump lying between two
fine granular tuffs (6), basalt-sheets. Cul nam Marbh, Canna.
whereof only a few
inches are visible, that /
pass up into a thin band bie
of dark shale (c), includ- “> SS (ayen:
ingalayer of pebbly fer- xf a7 SE

- - en < 5-D3G SS =
ruginous tuff, with small way Nes ae = ¢
= Sat 2s CAD yin awl Fe) SSS
rounded pea-like pieces ig oa a SSSSd

of basalt, basic pumice,

bole, limonite, ete. At the top of this shale an irregular parting of
coaly material (d) lies immediately under the slaggy base of the
succeeding basalt (¢). It will be observed that this upper lava cuts
out the shale and thus comes to rest directly upon the lower sheet.
At the point where it begins to descend it has caught up and enclosed
a small tree-stump (d’) which stands upright on the coaly parting
and shale. This stump, at the time of my visit, measured 5 inches
in height by 3 inches in breadth; it had been thoroughly charred
and was crumbling away on exposure, but among the pieces which
I took from it sufficient trace of structure can be detected with the
microscope to show the tree to have been a conifer.

(‘wuueg jo ‘nowy, sstpy Aq ydeiSojoyd @ morq) “AVaNVY “UQW NA

Le

ee ghsbe in Oa}

a
‘

se

TIAX ‘Id ‘II'T 10 ‘90g ‘Toop “Utnop *yreng

4
aa
uu
dl

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Z c :
>. F
—s ~ ‘ -
2 .
. 5
a”
; ci

- ' iS,

a:

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; - j .
nine _ _ »
- 4 ¥ 3 a
r ‘4
= we
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f ‘ ; zs
ee * .
. Fe: é .
r
i Pa é a = Cd ce ‘
“2 s 4
+ oe a
_ — ~ rs. ,
oe fi & - eee a ioe) a ie a A =< in = = -_ ae

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 363

We have here another instance of the deposition of volcanic dust
and fine mud in a pool that filled a hollow in the lava-field. Again
we see that the closing act of sedimentation was the washing of

‘vegetable matter into the pool, which was finally buried under
another outflow of basalt.

It is on the southern coast of the isle of Sanday that the higher
intercalations of sedimentary material among the basalts are most
instructively displayed. At the eastern end of this island, as already
stated, the lowest and coarsest conglomerate is visible on a skerry
immediately south of the headland of Ceann an Eilein. It doubt-
less underlies the Sanday cliffs, but is not there visible, for the
basalts descend below sea-level. These volcanic sheets have a slight
inclination westward; hence as we proceed in that direction we
gradually pass into higher parts of the series. In the Creag nam
Faoileann (Seamews’ Crag) and the gully that cuts its eastern end,
likewise in the two singularly picturesque stacks of Din Mor and
Dun Beag (Big and Little Gull Rocks), which here rise from the
foreshore, two distinct platforms of detrital material may be noticed
among the basalts. Both of these can be well seen on Din Mor,
which is represented in Pl. XVII. The lower band, 4 or 5 feet
thick, is here a rather coarse conglomerate, which lies upon a sheet
of scoriaceous basalt that extends up to the base of the Creag nam
Faoileann. It is directly overlain by another basalt, about 30 feet
thick, which dips seaward and forms a broad shelving platform,
whereon the tides rise and fall. On this stack a second coarse
conglomerate, about 10 feet thick, forms a conspicuous band about
a third of the height from the bottom; it is composed mainly of
well-rounded blocks of various lavas up to 18 inches or more in
diameter, but it contains also pieces of Torridon Sandstone. It is
covered by about 60 feet of basalt, which towards the base is some-
what regularly columnar, but passes upward into the wavy, starch-
like, prismatic structure.

If now we trace these two intercalated zones of conglomerate
along the shore, we find that they both rapidly change their charac-
ters and disappear. The lower, though formed of coarse detritus
under the Dun Mor, passes on the opposite cliff, in a space of not more
than 60 yards, into fine tuff and shale, about 6 feet thick, which
become carbonaceous at the top, where they are overlain by the next
basalt. A hundred yards to the east the band likewise consists of
tuffs and ashy shales, which underlie the basalts on the Dun Beag,
and again show the usual coaly layers at the top. On the eastern side
of the gully in the coast, about 160 yards north-east of Dun Mor,
the same band is reduced to not more than 3 feet in thickness,
consisting chiefly of fine conglomerate, wherein well waterworn
pebbles of Torridon Sandstone and epidotic grit appear among the
predominant volcanic detritus. This conglomerate is surmounted by
a few inches of dark carbonaceous mudstone orshale. Rough slagg
basalts lie above and below the band.

The upper conglomerate dies out, both eastward and westward,
in the cliff opposite the Din Mor, dwindling down at last to

364 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

merely a few pebbles between the basalts. It lies in a kind of
channel or hollow among these lavas, which in an east-and-west
direction cannot be more than about 65 yards broad.

Probably still higher in the series of basalts is another intercala-
tion of sedimentary layers which may be seen in the little bay to
the east of Tallabric, rather more than a mile to the west of the
Creag nam Faoileann. It rests upon a coarsely slaggy amygdaloid,
and is from 6 to 10 feet in thickness. The lower and larger part
of the deposit consists of greenish pebbly sandstone and fine con-
glomerate, largely composed of basaltic detritus, but including
abundant well-smoothed and polished pebbles of Torridon Sandstone,
green grit, quartzite, etc. The stones vary from mere pea-like:
pebbles up to pieces 2 or 3 inches long, the largest being:
generally fragments of slag and amygdaloid which are less water-
worn than the sandstones and other foreign ingredients. The
uppermost 2 or 3 feet of the intercalation consist of dark carbon-
aceous mudstone or shale, made up in large measure of volcanic
detritus, which may have been derived partly from eruptions of
fine dust, partly from subaerial disintegration of the basalt-sheets..
Some layers of these finer strata are full of remains of much
macerated plants.

Other thin coaly intercalations have been observed among the
basalts of Canna, some of which may possibly mark still higher hori-
zons than those now described. But, confining our attention to the
regular sequence of intercalations exposed along the Sanday coast, we
find at least four distinct platforms of interstratified sediment among
the plateau-basalts of this district. Each of these marks a longer
or shorter interval in the outflow of lava, and points to the action
of moviug water over the surface of the lava-fields.

We may now consider the probable conditions under which this
intervention of aqueous action took place. The idea that the sea.
had anything to do with these conglomerates, sandstones, and shales:
may be summarily dismissed from consideration. The evidence that.
the basalt-eruptions took place on a terrestrial surface is entirely
convincing, and geologists are now agreed upon this question.

Excluding marine action, we have to choose among forms of
fresh water—between lakes on the one hand and rivers on the other.
That the agency concerned in the transport and deposition of these
strata was that of a river may be confidently concluded on the
following grounds :—

1. The large size and rolled shapes of the boulders in the con-
glomerates. To move blocks several tons in weight, and not only
to move them but to wear them into more or less rounded forms,
must have required the operation of strong currents of water.
The coarse detritus intercalated among the basalts is quite comparable
to the shingle of a modern river, which descends with rapidity and
in ample volume from a range of hills.

2. The evidence that the materials of the conglomerates are not
entirely local, but include a marked proportion of foreign stones..

Vol, 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 365

The proofs of transport are admirably exhibited by the pieces of
Torridon Sandstone, epidotic grit, quartzite, and other hard rocks,
none of which occur in situ except at some distance from Canna.
These stones are often not merely rounded, but so well smoothed
and polished as to show that they must have been rolled along for
some considerable time in water.

3. The lenticular character and rapid lithological variations of
the strata, both laterally and vertically. The coarse conglomerates
die out as they are followed along their outcrop and pass into finer
sediment. They seem to occur in irregular banks, which may not
be more than 200 feet broad, like the shingle-banks of a river.
The coarser sediment generally lies in the lower part of the sedi-
mentary group. But cases may be observed, such as that shown in
fig. 16, p. 361, where the fine sediment laid down upon the bottom
conglomerate has subsequently been overspread by another inroad of
coarse shingle. Such alternations are not difficult to understand, if
they are looked upon as indicating the successive floods and quieter
intervals of a river.

For these reasons I regard the platforms of sedimentary material
intercalated among the basalts of Canna and Sanday as the successive
flood-plains of a river which, like the rivers that traverse the lava-
deserts of Iceland, flowed perhaps in many separate channels across
the basalt-fields of the Inner Hebrides and was liable to have its course
shifted from time to time by fresh volcanic eruptions. That this
river came from the east or north-east and had its source among the
western highlands of Inverness-shire may be inferred from the nature
of the stones which it has carried for 30 miles or more along its bed.
And that it crossed in its course the tract of Torridon Sandstone,
of which a portion still remains in Rum, is manifest from the
abundance of the fragments of that formation in the conglomerates.

With the remarkable exception of the section on Dun Beag, to be
immediately referred to, no trace of any eroded channel of this
river through the lavas of the great volcanic plain has been preserved.
Possibly frequent invasions of its bed by streams of basalt from
different vents hindered it from remaining long enough in one course
to erode anything like a gorge or cation. But, in any case, the main
channel of the river probably lay rather to the east of the present
islands of Canna and Sanday, on ground which is now covered by
the sea. The banks or sheets of boulder-conglomerate undoubtedly
show where its current swept with great force over the lava-plain,
but the manner in which these coarser materials are so often covered
with fine silt suggests that the sedimentary materials now visible
were deposited rather on the low grounds over which the stream
rushed in times of flood. Pools of water would often be left after
such inundations, and in these depressions silt would gradually
accumulate, partly carried in suspension by the river, partly washed
in by rain, while drift-wood that found its way into these eddies,
and leaves blown into them from the trees and shrubs of the sur-
rounding country, would remain for some time afloat, and would
be the last of the detritus to sink to the bottom. Hence, no doubt,

366 SIR A. GEIKIE ON THE TERTIARY [ May 1896,

the carbonaceous character of the hardened silt in the upper part of
each intercalation of sediment.

If we were to look upon the volcanic materials in the con-
glomerates as derived from the subaerial disintegration of the fields
of basalt, we should be compelled to admit a very large amount of
erosion of the surface of the volcanic plain during the period when
the river flowed over that tract. It would be necessary to suppose
not only that there was a considerable rainfall, but that the dif-
ferences of temperature, either from day to night or from summer
to winter, were so great as to split up the lavas at the surface in
order to provide the river with the blocks which it has rolled into
rounded boulders. I do not think, however, that such a deduction
would be sound. If we compare the materials that have filled up
the eruptive vent at the eastern end of Canna with the great majority
of the blocks in the coarse conglomerates, we cannot fail to note
their strong resemblance. The abundance of lumps of slaggy lava
in the river-shingle corresponds with their predominance in the
agglomerate of the vent. The boulders of basalt, dolerite, and
andesite which crowd the conglomerates need not have been derived
from the action of atmospheric waste on the lava-fields, but might
quite well have been mainly supplied by the demolition of one or
more volcanic cones of fragmental materials.

That such has really been the chief source of the blocks in the
conglomerates I cannot doubt. At the eastern end of Canna we
actually detect a volcanic cone partly washed down and overlain by a
pile of river-shingle. There were probably many such mounds of slag
and stones along lines of fissure all over the lava-fields. The river
in its winding course might come upon one cone after another, and
during times of flood, or when its waters burst through any tem-
porary barrier created by volcanic operations it would attack the
slopes of loose material and sweep their detritus onward. At the
same time, the current would carry forward its own natural burden
of far-transplanted sediment, and hence on its old flood-plains, buried
and preserved under sheets of basalt, we find abundant pebbles of
the old Highland rocks which it had borne across the whole breadth
of the basaltic lowland.

But the destruction of volcanic cones was probably not the only
source of the detritus that now forms the conglomerates of Canna
and Sanday. I have shown that these conglomerates pass laterally
into tuffs, and are sometimes underlain, sometimes overlain, with
similar material. It is quite obvious that their deposition was
contemporaneous with volcanic action in the immediate neighbour-
hood, and that at least part of their finer sediment was obtained
directly from volcanic explosions. In wandering over the coast-
sections of these remarkably coarse deposits, I have been impressed
with the enormous size of many of the stones, their resemblance to
the ejected blocks of the agglomerate and the distinction that may
sometimes be made with more or less clearness between their rather
angular forms and the more rounded and somewhat waterworn
aspect of the other boulders. It seems to me not improbable that

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 367
some of the remarkably coarse masses of unstratified conglomerate
in Canna Harbour consist largely of ejected blocks from the adjacent

vent.
The only instance which I have observed of erosion of the basalts

contemporaneous with the operations of the river that spread out
this conglomerate is to be found in the striking stack of Din Beag
This extraordinary monument of geological

already alluded to.’

history forms an outlying obelisk which rises from the platform of
the shore to a height of about 70 feet. Seen from the south-west
it appears to consist entirely of bedded basalt resting on some
stratified tuff and shale which intervene between these lavas and
that of the broad platform of basalt on which the obelisk stands.

Fig. 18.—WSection of the eastern front of the Din Beag.

a alae ¢

’
‘
'
‘
!
t
4
:
'
i
i
‘
t
‘
H
(
:
.
?
i

/
H
}

i
f
J Pe nega

Sy = oe =
eg TVs 9, PURER [Spi

a. Very slaggy amygdaloidal basalt.

b. Shales and tuff.

c. Slaggy and jointed basalts.
The dotted lines indicate the supposed form of the ravine.

d. Conglomerate.
é. Prismatic basalt.

ase7

—«

On that side it presents no essential difference from the structure
of the Din Mor on the west, save that the lower conglomerate of
that outlier is here represented by fine sediment, and the upper
conglomerate is wanting. ‘The general aspect of this south-western

1 This pinnacle of rock is referred to by Macculloch in his account of Canna,
and is figured in pl. xix. fig. 3 in his work already cited. But neither his
description nor his drawing conveys any idea of the real structure of the rock.

368 SIR A. GEIKIE ON THE TERTIARY [May 1896,

front of the stack is shown in Pl. XVIII. If, however, we approach
the rock from the coast-gully to the north, we form a very different
impression of its structure. It then appears to consist chiefly of
conglomerates with a capping of basalt on the top. It is not until
a close scrutiny is made of the eastern and western faces of the
column that the true structure and history of this singular and
striking piece of topography become apparent.

On the eastern front the section represented in fig. 18, p. 367, is
exposed. At the bottom, forming the pediment of the column, lies a
sheet of slaggy and vesicular or amygdaloidal basalt (a), which shelves
gently in a south-westerly direction into the sea. The lowest band
(6) in the structure of the stack is a thin group of lilac, brown, and
ereen shale and volcanic mudstone or tuff, which encloses pieces of
coniferous wood, and becomes markedly carbonaceous in its upper-
most layers. Above these strata on the southern front comes the
pile of bedded basalts (c) with their slaggy lower and upper surfaces.
But as we follow them round the eastern side we find them abruptly
cut off by a mass of conglomerate (d). That the vertical junction-
line is not a fault is speedily ascertained. The lower platform of
slaggy basalt runs on unbroken under both the shales and the con-
glomerate. Moreover, the line of meeting of this conglomerate with
the basalts that overlie the shales is not a clean-cut straight wall,
but displays projections and recesses of the igneous rocks round and
into which the materials of the conglomerate have been deposited.
The pebbles may be seen filling up little crevices, passing under over-
hanging ledges of the basalts, and sharply truncating lines of scoria-
ceous structure in these rocks. ‘The same relations may be observed
on the western front of the stack. There the ashy shales and tufts
are sharply cut out by the conglomerate which wraps round and
underlies a projecting cornice ,
of the slaggy bottom of the Fig. 19.—Enlarged section on the
basalt that rests on the strati- western side of the Dun Beag.
fied band (fig. 19).

The conglomerate is rudely
stratified horizontally, its bed-
ding being best shown by
occasional partings of greenish
sandstone. It consists of well-
rounded, polished, and water-
worn stones, chiefly of mem-
bers of the volcanic series,—
basalts, and dolerites, both
compact and amygdaloidal or
slaggy,—but with a conspicuous
admixture of Torridon Sand- a, amygdaloid; , tuff; c, ashy shales;
stone, gneiss, grey granite, grit, d, layer of coaly shale; e, amyg-
and different schists. The daloidal basalts; /, conglomerate.
coarsest part of the deposit
lies towards the bottom, where the volcanic blocks are some-
times 6 and 8 feet in diameter. Some of these large masses

Pi es
Nero

V6

“QO.

sep

(‘eauey jo ‘mony, sstyy fq ydesSojoyd 8 wor)
*“ISUM-HLOOS HHL WOUd Naas ‘AVaNVY ‘ovag NQ(T

—— —

ill

TITAX ‘Id ‘II'T ‘TOA “20g ‘Toop “UAnop “y-reng

~ co

Quart. Journ. Geol. Soc. Vol. LII. Pl. XIX.

Din Bua, SANDAY, SEEN FROM THE NORTH, ‘THE ISLAND oF Kum IN THE DISLANCE.

(From a photograph by Miss Tuom, of Canna.)

—

‘Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE, 369

may have originally fallen from the basalts against which the
conglomerate now reposes. The far-transported stones are also of
considerable size, pieces of granite and gneiss frequently exceeding
a foot in length. The well-rounded pebbles of foreign materials
have been washed into the interstices between the large volcanic
blocks.

Itis, I think, tolerably clear that the wall of basalt against which
this conglomerate has been laid down is one of erosion. The beds
of basalt have here been trenched by some agent which has likewise
scooped out the soft underlying shales, and even cut them away from
under their protecting cover of basalt, as shown in figs. 18 & 19.
There can be little hesitation in regarding this agent as a water-
course which for some considerable interval of time continued to dig
its channel through the hard basalts. There is not room enough
between the basalt-wall of the Dun Beag and the opposite cliffs of the
shore (where no trace of this conglomerate is to be seen) for any
large stream to have found its way. I do not, therefore, seek to
identify this relic of an ancient waterway with the channel of
the main river which deposited the conglomerate-bands of Canna
and Sanday. More probably it was either a mere torrential chasm
or a tributary stream, draining a certain part of the volcanic plateau
and allowed to retain its channel long enough to be able to erode it
to a depth of nearly 50 feet. Erosion had reached down through the
underlying tuffs to the slaggy basalt below, but before it had made
any progress in that sheet its operations were brought to an end
at this locality by the floods that swept in the coarse shingle and
by the subsequent stream of basalt, of which a mere outlying
fragment now forms the upper third of the stack (e¢ in fig. 18),

The ravine or gully of the Dun Beag probably lay within reach of
the floods of the main river, as may be inferred from the number
and size of the far-transported rocks in its conglomerate. The
conditions of deposition remained little changed during the process
of filling up with detritus, except that the largest blocks of rock
were swept into the chasm in the earlier part of its history, while
much smaller and more waterworn shingle was introduced towards
the close.

Denudation, which has performed such marvels in the topography
of the West of Scotland since older Tertiary time, has here obliterated
every trace of this ancient gully, save the little fragment of one of
the walls which survives in the stack of Din Beag. When in the
course of centuries this picturesque obelisk shall have yielded to
the action of the elements, the last leaflet of one of the most
interesting chapters in the geological history of the Inner Hebrides
will have been destroyed.

The question naturally arises, What was the subsequent history
of the river which has left so many records of its floods entombed
among the basalts of Canna and Sanday? In particular, can any
connexion be traced or plausibly conjectured between it and the
river-bed preserved under the Scuir of Eigg?

In dealing with this subject, though the evidence is admittedly

370 SIR A. GEIKIE ON THE TERTIARY [May 1896,

scanty, we are not left wholly to conjecture. A consideration of
the general topographical features of the wide region of the Inner
Hebrides, from the beginning of the volcanic period onward, will
convince us that, in spite of the effects of prolonged basalt-eruptions,.
the persistent flow of the drainage of the Western Highlands must
have taken a westerly direction. It was towards the west that the
low grounds lay. Though the long and broad valley which
stretched northwards from Antrim between the line of the Outer
Hebrides and the West of Scotland was gradually buried under a
depth of 2000 or 3000 feet of lava, the volcanic plain that over-
spread it probably remained even to the end lower than the
mountainous Western Highlands. Hence the rivers, no matter
how constantly they may have had their beds filled up and may
have been driven into new channels, would nevertheless always
seek their way westward into the Atlantic.

On Canna and Sanday we have the traces of a river which poured
its flood-waters across the lava-fields in that part of the volcanic
region, while the basalts were still from time to time streaming
from vents and fissures. Not more than 14 miles south-east stands
the Scuir of EHigg, with its buried river-channel and its striking
evidence that this river likewise fiowed westward, though at a far
later time, when the basalt-eruptions had ceased and the volcanic
plain had been already deeply trenched by erosion, but when the
subterranean fires were not yet quenched.

When one reflects upon the enormous denudation of this region,
to which further reference will be made in the sequel, one is not
surprised that many connecting-links should have been effaced.
The astonishment rather arises that so continuous a story can still
be deciphered. Even, however, had the original record been left
complete, it would have been exceedingly difficult to trace the suc-
cessive mutations of a river-channel during long ages of volcanic
eruptions. Such a channel would have been concealed from view
by each lava-stream that poured into it, and would not have been
again exposed save by the very process of erosion that destroys
_ while it reveals.

While, therefore, there is not and can never be any positive
proof that in the fluviatile records of Canna, Sanday, and Higg
successive phases are registered in the history of one single stream,
I believe that this identity is highly probable. It was a river
which rose among the mountains of Western Inverness-shire, and
had already taken its course to the sea before any volcanic eruptions
had begun. It continued to flow westward across the lava-floor
that gradually spread over the plains. Its channel was constantly
being filled up by fresh streams of basalt, or deflected by the uprise
of new cinder-cones. But, fed by the Atlantic rains, it maintained
its seaward flow until the general subsidence which carried so much
of the volcanic plain below the sea. Yet the higher part of this
ancient watercourse is no doubt unsubmerged, still traversing the
schists of the Western Highlands as it has done since older Tertiary
time. It may, perhaps, be recognized in one of the glens which

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESETRN EUROPE. 371

carry seaward the drainage of the districts of Morar, Arisaig, or
Moidart.

When one scans the great precipice on the western side of the
island of Eigg, which displays a transverse section across the
pitchstone-lava with its buried river-bed and the basalt-plateau
underneath, there seems no chance of any further westward trace
of this pitchstone being ever found. The truncated end of the
Scuir looks from the top of the cliff out to sea, and the progress of
denudation might have been supposed to have effectually destroyed
all evidence of the continuation of the rock in a westerly direction.
Some years ago, however, my friend Prof, Heddle, while cruising
among the Inner Hebrides, landed upon the little uninhabited islet
of Hysgeir, which rises out of the open sea, some 18 miles to the
westward of Kigg. He at once recognized the identity of the rock
composing this islet with that of the Scuir, and in the year 1892
published a brief account of this interesting discovery.’

I have myself been able to land on Hysgeir in two successive
summers, and can entirely confirm Prof. Heddle’s identification.
The islet stands on the eastern edge of the submarine ridge which,
running in a north-easterly direction, culminates in the island of
Canna. Hysgeir is a mere reef or skerry, of which the top rises
only 38 feet above the Ordnance datum-level. Its surface is one of
bare rock, save where a short but luxuriant growth of grasses has
found root on the higher parts of two or three of its ridges, and on
the old storm-beach of shingle which remains on the summit. The
rock undulates in long low swells that run in a general direction
20° to 45° west of north, and are separated by narrow channels or
hollows. The place is a favourite haunt of gulls, terns, eider-ducks,.
and grey seals, and is used by the proprietor of Canna for the
occasional pasturage of sheep or cattle. So numerous are the
sea-fowl during the breeding-season that the geologist, intent upon
his own pursuits, may often tread unawares on their nests, while
he is the centre of a restless circle of white wings and anxious
cries.

The pitchstone of Hysgeir, like that of Higg, is columnar, the
columns being irregularly polygonal and varying from 3 to 10
inches in diameter. They are packed so close together that the
domes of rock on which their ends appear look like rounded masses
of honeycomb. They may here and there be observed to be
arranged radially, with their ends at right angles to the curved
exterior of the ridges, as if this external surface represented the
original form of the cooled pitchstone, and were not due to mere
denudation. There can be no doubt, however, that the island has
been well ice-worn.

At the north-western promontory a beautiful example of fan-
shaped grouping of columns may be observed on a face of rock which
descends vertically into the sea. Here, too, is almost the only
section on which the sides of the columns may be examined, for, as
1 Appendix C to ‘A Vertebrate Fauna of Argyle and the Inner Hebrides,;
by J. A. Harvie-Brown and Thomas E. Buckley, p. 248.

Q.J.G.S8. No. 206, 2c

372 SIR A. GEIKIE ON THE TERTIARY [May 1896,

a rule, it is merely their ends on the rounded domes which are to -
be observed, and which everywhere slip under the waves. The
columns in a cliff from 15 to 20 feet high show the slightly wavy,
starch-like arrangement so often to be met with among the
plateau-basalts.

The rock presents a tolerably uniform texture throughout, though
in some parts it is blacker, more resinous, and less charged with
porphyritic enclosures than in the general body of the rock. Large
fresh felspars are generally scattered through it. To the naked eye
it reproduces every feature of the pitchstone of the Scuir of Eigg.

A microscopic examination completes our recognition of the
identity of these two rocks. Mr. Harker has examined a thin
slice prepared from the Hysgeir pitchstone, and remarks regarding it
that ‘the large felspars are not the only porphyritic element. The
microscope shows the presence also of smaller imperfect crystals of
augite, very faint green in the slice, and small grains of magnetite.
The felspars have been deeply corroded by the enveloping magma,
and irregular included patches of the groundmass occupy nearly
half the bulk of some of the crystals. This latter feature is seen
especially in some of the larger crystals, which seem to be sanidine.
They are, for the most part, apparently simple crystals, but in
places there is a scarcely defined lamellar twinning, or, again, small
patches not extinguishing with the rest; so that we are probably
dealing with some perthitic intergrowth on a minute scale.’

‘Rather smaller felspar-crystals are rounded by corrosion, but:

lack the inclusions of groundmass; these have albite- and some-
times pericline-lamellation, and may be referred to oligoclase-
andesine. The groundmass of the rock is a brown glass with
perlitic cracks, enclosing very numerous microlites of felspar about
-001 inch in length [6619]. The rock is probably to be regarded
as a dacite rather than a rhyolite, and thus agrees with Mr. Barker-
North’s analysis of the Eigg pitchstone.’* There is no trace of
any conglomerate im situ like that under the Scuir of Higg, nor of
any other rock, aqueous or igneous. As the pitchstone everywhere
slips under the sea, its geological relations are entirely concealed.
_ The great variety of materials met with in the form of boulders
on Hysgeir is a testimony to the transport of erratics from the
neighbouring islands and the mainland during the Glacial Period.
The most abundant rock in these boulders is Torridon Sandstone,
derived, no doubt, from the hills of Rum; but there occur also
various kinds of schist, gneisses, quartzites, granites, porphyries,
probably from the west of Inverness-shire, as well as pieces of white
sandstone, probably Jurassic, which may have come from Kigg.

That the pitchstone of Hysgeir is a continuation of that of the
Scuir may be regarded as highly probable. If not a continuation,
it must be another stream of the same kind, and doubtless of the
same date. If it be regarded as probably a westward prolongation of

1 Comp. Prof. Judd’s remarks on the Scuir of Higg rock, Quart. Journ. Geol.

Soe. vol. xlvi. (1890) p. 380.
9 Tbid. p. 379.

‘Vol. 52.] | BASALI-PLATEAUX OF NORTH-WESTERN EUROPE. 373

the Eigg rock, and if it is about as thick as that mass at the western
end of the Scuir, then its bottom lies 200 or 300 feet under the
waves. The river-channel occupied by the Eigg pitchstone un-
doubtedly sloped from east to west. The position of Hysgeir, 18
miles farther west, indicates a further fall in the same direction at
the rate of perhaps as much as 35 feet in the mile.!. Unfortunately,
however, as no trace of the river-bed can now be seen on this
island, any statement in regard to its prolongation must rest on mere

conjecture.

IV. Tue Basic Srts.

One of the most characteristic structural features in the basalt-
plateaux of North-western Europe is the number, thickness, and
extent of the basic sills or intrusive sheets which accompany these
piles of volcanic material. As I have formerly shown,’ the sills,
though they may be observed in any part of the basalt series, are
more particularly developed at its base, and are notably interpolated
among the Secondary formations which underlie it. In addition to
the examples which I have already described, the following localities
are here cited as affording excellent illustrations of the more

characteristic features of intrusive sheets.

The eastern coast of Skye has been classic ground for this part of
volcanic geology since the publication of Macculloch’s descriptions
and diagrams. From the mouth of Loch Sligachan to Rudha
Hunish, at the northern end of the island, a series of sills may be
traced, sometimes crowning the cliffs as a columnar mural escarp-
ment, sometimes burrowing in endless veins and threads through
the Jurassic rocks. The horizontal distance to which this band of
sills extends in Skye is not far short of 30 miles. But it stretches
beyond the limits of this island. It forms the group of islets
which prolong the geological structure and topographical features of
Trotternish for 4 miles farther to the north-west. It reappears
10 miles still farther on in the Shiant Isles. Thus its total visible
length is fully 40 miles. As a display of intrusive basic igneous
rocks it ranks next to the Great Whin Sill among the British
instances of this tectonic type.

The larger sheets in this belt have certain characteristic fea-
tures. They are generally somewhat coarsely crystalline ophitic
dolerites or diabases, and exhibit the persistent uniformity of com-
position and structure so characteristic of intrusive sheets and dykes.
They display in many cases a regularly prismatic arrangement, the
columns being much thicker and longer than those of the basalts
of the plateaux or those of the dykes and veins. The regularity of
this structure is well shown in the great sill of which the Kilt Rock
is one of the most noted portions (fig. 20, p. 374). But the most
astonishing example is that which forms the Garbh Eilean of the
Shiant Isles, where the sill presents to the sea a vertical columnar

1 Rep. Brit. Assoc. 1894 (Oxford meeting), p. 653.
2 Quart. Journ. Geol. Soc. vol. xxvii. (1871) p. 296; Trans. Roy. Soc, Edinb,

vol. xxxv. (1888) p. 111.
202

[-Buream® uaouy-TJos 074 Jo W100 et} 07 nvayeyd-s,eseq 044 Jo uoyasod @ SI 4JeT ON} UO punos3 ysty our]

‘ahg “ysvutano.y, “UywoUnry JO 1809 DID.YS DISSHINS UL aMIsNgUL [prs LNUUUNNOQ—')G “SL

Vol. 52.] |THE TERTIARY BASALT-PLATEAUX OF N.W. EUROPE. 375

wall 500 feet high. Though I could not certainly trace any single
column continuously from bottom to top of the precipice, many of
them must be at least 300 or 400 feet long. No other sill in the
British Islands forms such a noble escarpment as this.

In contrast to such enormous thicknesses of intrusive material,
instances may be culled from the same belt of sills where the molten
rock has been injected in thin cakes and mere threads into the
Jurassic sandstones and shales, or into the shales and coals inter-
ealated among the plateau-basalts. Thus, on the cliff immediately
north of Ach na Hannait, between Loch Sligachan and Portree
Bay, the section which is represented in fig. 21 may be seen.

Fig. 21.—Section of thin intrusive sheets and veins in carbonaceous
shales lying among the plateau-basalts. Cliff north of Ach na
Hannait, between Portree Bay and Loch Sligachan.

Pom

Pans ey) COr

aS : )y
OBER Sv ¢
Li = 2 j

Ty, Ee

a

TT

i Mi

> = => = =

= 9

= = ~ aan <= ~
Se

SS Ul lg,
———— lig C

}

f R= ATT es =
im SS Si ~ > “Ui ert
= sss — = Mit

At the base lies a vesicular dolerite with a slaggy upper surface (a).
Next comes a zone of sedimentary material about 5 or 6 feet
thick, the lower portion consisting of an impure coal, which passes
towards the right hand into brown and grey carbonaceous shale
‘with plant-remains (6). This coaly layer has been already alluded
to as probably lying on the same horizon with the coal of Portree.
Traced northward, it is found to have a bed of fine tuff beneath it,
and sometimes a volcanic breccia or conglomerate. It fills up rents
in the underlying slaggy lava, and was undoubtedly deposited upon
the cooled surface of that rock. Immediately above this lower band
the black carbonaceous shale (d) which follows has been invaded by
an extraordinary number of thin cakes or sills, and also by veins
or threads of basalt. For a thickness of 2 or 3 feet the band
consists mainly of these intrusions, which, in the form of a fine

376 SIR A, GEIKIE ON THE TERTIARY [May 1896,

grey basalt, vary from less than 1 to 3 or 4 inches in thickness.
They are separated by thin partings of coaly shale, and as they
tend to break up into detached nodule-like portions, especially
towards the right hand of the section represented in fig. 21, they
might, on casual inspection, be easily mistaken for nodules in the
dark shales. Somewhat later in the time of intrusion are veins
of basalt which, as at c, break across the nodular sills, and sometimes
expand into thicker beds (c’).

I have never seen such a congeries of minute sills among the
Tertiary basalt-plateaux as that here exhibited. In a space of
about 3 feet of vertical height there must be more than a dozen
roughly parallel cakes of intrusive rock. Veins (¢) run up from
the chief band of eruptive material into the overlying finely
vesicular basalt (f). The dyke (g) is probably the youngest rock
in the section.

The amount of contact-metamorphism effected even by such
thick sills as those of Trotternish and Shiant is much less than
might be expected. It seldom goes beyond a mere induration of
the strata for a few yards, often only for a few inches from the
surface of junction. In the Shiant Isles the shales on which the
sills rest have undergone a remarkable alteration. They have
been greatly indurated, and have acquired a globular or botryoidal.
structure. The spheroidal aggregates vary from not more than a
line to more than half an inch in diameter, and appear on the
surface as dark, irregularly grouped, pea-like aggregates. This
structure is perhaps best Boveloped immediately under the thick
sill that forms Eilean Muirhi.!

On the western side of Skye, owing to greater local subsidence of
the basaltic plateau, the base of the volcanic series is seldom seen,
and hence the platform of sills is for the most part concealed under
the sea. But where at one or two points the Jurassic strata are
brought up to the light of day, they have carried with them their
intrusive sheets of basic rock. Thus, at the mouth of Dunvegan
Loch, the islets of Mingay and Clett form parts of a sill which rests
on shell-limestones full of oysters (Ostrea hebridica), referable to the
Loch Staffin group of the Great Oolite Series. This rock, when
observed from a little distance, presents the usual regularly pris-
matic or columnar structure so well developed among the Trotter-
nish sills, but on a closer view shows this structure much less
distinctly. It is an olivine-dolerite of medium and fine texture,
which in thin slices displays under the microscope a distinctly
ophitic structure, the abundant light-brown augite enclosing the
striated felspars. Its lowest portion, from 3 to 7 or 8 inches
upward from the bottom, is much closer-textured than the rest of
the rock and is finely amygdaloidal. Its vesicles are in many
cases drawn out to a length of 3 or 4 inches, and the zeolites which
now fill them look like parallel annelid tubes or stems of Lithostrotion.
It is noteworthy also that the elongation of the vesicles has

3 Macculloch, ‘ Description of the Western Islands,’ vol. i. (1819) p. 441.

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 377

sometimes taken place at right angles to the surface of contact
with the underlying strata. But the most remarkable feature
in this sill is the surface which it presents to the oyster-beds on
which it rests. The fine-grained dark dolerite has there assumed
the aspect of a sheet of iron-slag, with a smooth or wrinkled,
twisted, ropy surface, which displays fine curving flow-lines.
No one looking at a detached specimen of this surface would be
ready to admit that it could possibly have come from anything
but a true lava-stream that flowed out at the surface. The
contours of a viscous lava are here precisely reproduced on the
under surface of a massive sill.

A little farther south the promontory of Eist, which forms the
western breakwater of Moonen Bay, is formed by another important
sill or group of sills which has insinuated itself among shales, shell-
limestones, and shaly sandstones, full of Ostrea hebridica, Cyrena
aurata, etc., and belonging to the Loch Statlin group of the Great
Oolite Series. The shore-cliff below the waterfall affords the
section given in fig. 22, illustrating the manner in which a
thick intrusive sheet may sometimes give off thin veins from its
mass. The rock attains on the Eist promontory a thickness of

Fig. 22.—Upper part of sill in Moonen Bay, Waternish, Skye,
showing the divergence of veins.

. =e ae “Ti ‘

OL GTECRIFCE Wr Tre:
, NL pen TF)

a. False-bedded shaly sandstone; 5. Shell-limestone (Great Ooiite Series) ;
¢e. Dolerite-sill; dd. Veins proceeding from the sill. Length of section=
about 5 yards.

probably at least 100 feet, where it is thickest and undivided. But
the two main sheets, or branches of one great sheet, on this peninsula
have probably an united depth of more than 300 feet. Landwards
the rock splits up and encloses cakes of the Jurassic strata. It
possesses the usual prismatic structure and doleritic composition.
In Moonen Bay, as shown in fig. 22, it presents a banded structure,
marked especially by alternation of lines of amygdules and layers of
more compact and solid dolerite, with occasional enclosed cakes of
baked shale or sandstone. Its upper surface is somewhat uneven,
and from it are given off narrow, wavy, ribbon-like veins (d), from

378 : SIR A. GEIKIE ON THE TERTIARY [May 1806,

less than 1 to 3 inches or more in width, which keep in a
general sense parallel to the top of the sill, but at a distance of a
few inches or feet from it. The sill becomes as usual fine-grained
towards the contact, the shales and sandstones being indurated and
the limestone marmorized.

Still farther south the bottom of the basalt-plateau is again
reached in the Sound of Soa, where the volcanic pile has been
poured out over the upturned edges of the Torridon Sandstone. It
is hardly possible to exaggerate the wild confusion of sills, dykes,
and veins which have been injected among the rocks at and on
both sides of the unconformability. Endless sheets of basalt and
dolerite have forced their way between the bedded basalts and the
sandstones, while across the whole rise vast numbers of dykes and
veins. Narrow, black, wavy ribbons of basic material cross many of
these veins, while the later north-western dykes cut sharply through
everything older than themselves. Asa natural section for tne study
of the phenomena of intrusion in many of their most characteristic
phases, I know no locality equal to the northern coast-line of the
Sound of Soa, unless it be the cliffs of Ardnamurchan. But the
Skye cliffs, though less imposing than those of the great Argyle-
shire headland, have this great advantage, that instead of being
exposed to the full roll of the open Atlantic, they form the margin
of a comparatively sheltered strait, and can thus be conveniently
examined,

There is one remaining locality in Skye to which I wish to direct
attention, since it displays certain phenomena of sills which I have
never seen so perfectly exhibited elsewhere. It lies on the western
side of the promontory of Sleat, about midway between the basalt-
plateau of Strathaird and that of Higg, and about 8 or 9 miles.
in a direct line from either. The basalts cannot be proved to have
once stretched continuously between Eigg and Strathaird, and to have
covered this part of Sleat; but the position of the rocks which I am
about to describe makes it probable that this continuation did formerly
exist. The denudation of the West of Scotland since early Tertiary
time has been so stupendous that I am prepared for almost any
seemingly incredible evidence of its effects. There cannot be any
doubt, however, that the rocks of which I now speak belong to the
great platform of intrusive sheets, and that they were injected
under a pile of Secondary strata, if not also of Tertiary basalts,
which has here been entirely removed.

In his map of Skye Macculloch showed a small outlier of ‘trap’
on the western side of the promontory of Sleat. The locality was
visited by Prof. Judd, who called the rock a ‘phonolite.’”* During
an excursion last year with my colleague Mr. C. T. Clough, I was
able to examine the place and to obtain the facts which I now
describe.

At Rudh’ an Iasgaich, about 2 miles from the Point of Sleat,
a small outlier of conglomerate lies on the edges of the Torridon

1 Quart. Journ. Geol. Soc. vol. xxxiv. (1878) p. 692.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 379

Sandstone. This deposit has been correctly identified by Prof. Judd
with the similar strata which in Skye and elsewhere on the west
coast of Scotland underlie the Liassic series. It is here about
10 or 12 feet thick, reddish and yellowish in colour, and distinctly
calcareous. Its component pebbles consist largely of Cambrian
(Durness) limestone, quartzite, and Torridon Sandstone—rocks which
all occur in situ in Sleat. It may be compared with the limestone-
conglomerates of Strath, and those which underlie the Lias at Heast
on Loch Eishort.' That here, as elsewhere in this region, the
basement-conglomerate was followed by the rest of the Lias and
Oolites may be inferred with some confidence from the copious
development of the Jurassic Series a few miles off, both to north and
south. But the whole of this overlying succession of formations
has here been swept away, and, but for the protection afforded
by the eruptive rocks of Rudh’ an Iasgaich, the conglomerate would
likewise have disappeared.

Above the conglomeratic band lies a sheet of intrusive rock, which
in one place has apparently cut it out, so as to rest directly upon
the Torridon Sandstone (a in fig. 23, p. 380). The decay of the softer
detrital rock underneath has caused the sill to break off in slices,
which have left behind them a bold mural escarpment.

The rock of this sill (6 5) is a rather coarsely-crystalline porphyritic
olivine-dolerite, which towards the north attains a thickness of
about 70 feet. It exhibits the usual prismatic jointing, though less
perfectly than some of the Trotternish sills already referred to.
Besides these vertical joints, it is also traversed by a system of
horizontal divisional planes which, though somewhat irregular in
their course, run, in a general sense, parallel to the upper and
ander surfaces of the sill.

It seems to have been along this transverse series of joints that
a second sill (c), 5 or 6 feet thick, has been injected. The material
of this younger intrusion is a black, finely crystalline dolerite or
basalt, with rudely prismatic jointing. Its most striking feature,
besides its regularity of position and persistency for several hundred
yards as a platform along the shore, is the basalt-glass which marks
both its under and upper surfaces of contact, and which is here
developed upon a scale the equal of which I have not met with
among the Tertiary sills of this country.

The selyage of glass appears as a black tar-like layer, varying
from a mere film to 2 or 3 inches in thickness. It is found not
only on the upper and under surfaces, but descends along abrupt
step-like interruptions of the upper surface, a foot or more in
height, as if the sill had been broken by a series of subsidences.
The apparent fracture, however, is probably due to the irregularities
of the passage forced for itself by the molten rock, as it passed from
one line of horizontal joint to another through the heart of the
older sheet.

The exposed surface of black glass on the top of the younger sill

1 Op. cit. vol. xiv. (1858) p. 9; vol. xliv. (1888) p. 71.

380 SIR A. GEIKIE ON THE TERTIARY [May 1806,.
exhibits long parallel lines, probably marking flow-structure, which
are made conspicuous by a pale yellow, ferruginous, weathered crust..
Portions of the larger intrusive sheet have been broken off and
involved in the later rock. The observer cannot fail to be impressed
by the prodigious force with which the sills were injected, when.
he sees here that a thick sheet of solid dolerite has been actually

Fig. 23.—Section of dolerite-sill cut by another sill, both bemg
traversed by dykes, Rudh’ an Iasgaich, western side of Sleat, Skye.

ke Sea
ANTI TANN
AAT

S
NN

—

‘o™

aN a

| SN

Sue TI Tmo A

A AS
teas) bo ee

EXER,
d ha

6
wis
ANN
Ay

split open along the middle.

The younger sill disappears to the
north, and is not found in the cliff of Rudha Charn nan Ceare,

where the thick sill, lying once more on the band of conglomerate,.
forms a fine escarpment above the shore. Dykes of fine-grained
basalt with compact chilled margins rise through both sills, together

ribbon.

nowhere visible.

with veins which pursue a wavy upward path like strips of black

Fig. 24.—Sill traversing bedded basalts, cliffs of Stromé, at
the entrance of the Vaagofjord.

[The caves and notches shown at the bottom of the precipice mark the position’
of the vents represented in Pl. XV. and figs. 8, 9, & 10.]

In the Faroe Islands the actual base of the volcanic series*is-

Hence, the great lower platform of intrusive

sheets being there concealed, this feature of the basalt-plateaux is

less conspicuous than it is in the Inner Hebrides.

A number of

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 381

sills, however, have been noticed by
previous observers, and I have seen
others on the sides of Stromd, Kalso,
Kuné, and other islands.

The most remarkable sill in the
Faroe Islands is probably that which
forms so prominent an object on the
western cliffs of Strom, at the en-
trance into the Vaagéfjord (figs. 24,
25). It is prismatic in structure,
and where it runs along the face
of the cliffs, parallel to the bedded
basalts among which it has been in-
truded, presents the familiar charac-
ters of such sheets. It runs along
the face of the precipice which rises
above the row of volcanic vents
already described. But it there
begins to ascend the cliffs obliquely
across the basalts, until it reaches the
crest of the great wall of volcanic
rock at a height of probably about
1000 feet above the waves. From
the crest of the precipice the up-
ward course of this sill is continued
into the interior of the island. It
pursues its way as a line of bold
crag along the ridges of the plateau,
gradually ascending till it forms the
summit of one of the most prominent
hills in the district.

Some further idea of the enormous
energy with which the sills were in-
jected may be formed from this
example, where the eruptive mate-
rials followed neither the line of
bedding nor a vertical fissure, but
took an oblique course through the
plateau-basalts for a vertical distance
of probably more than 1500 feet.

In Skye a series of remarkable
compound sills occurs where a central
sheet of acid rock is overlain and
underlain by a layer of basic mate-
rial. I have already described some
examples of this structure, and will
cite some others in a later part of
this paper.

‘LS

ey

CET Np TEN ope ETE
f

eeneng een

ty

\

>

;
af
ta
=
oe
AN
cz

‘Mayoy fo punjsr ay7 apsoddo yauunyo ay2 wort woos Qs owns yp fo mar.4 —'GZ *S1iT

‘ See in particular the description by
Trevelyan and Allan, and references by Prof.
James Geikie and Mr. Lomas already cited.

382 SIR A. GEIKIE ON THE TERTIARY [May 1896,

V. Tue Dyxss,

I have little to add to the full description already given by me
of the system of dykes which forms so important a feature in the
volcanic history of Tertiary time throughout the North-west of
Kurope. It is difficult to establish any criterion of the relative
dates of protrusion of the dykes ; but the important fact announced
by me so far back as 1857, that some are older and some later
than the great acid bosses of the Inner Hebrides, has been fully
confirmed by more recent research all over the region. So far as
may be inferred from the geology of the Red Hills of Skye and
their surroundings, the vast majority of the dykes belong to a time
anterior to the uprise of the bosses of granophyre. As an example
of the way in which these bosses truncate the dykes, I may cite
here a fresh illustration from the granophyre of Ben an Dubhaich,
near Torrin in Skye. The Cambrian limestones of that part of
Strath are traversed by numerous dykes which stop short at the edge
of the acid rock. As the actual lines of junction are not always
visible, it might be contended that the dykes are not necessarily
older than the granophyre, but may actually be younger, their
sudden termination at the edge of the acid boss being due to their
inability to traverse that rock. That this explanation is untenable
is readily proved by such sections as that given in fig, 26, where a
basic dyke 9 or 10 feet broad run-
ning through the Cambrian lime- Fig. 26.—Ground-plan of basie
stone of Torrin is abruptly cut off dyke (b) in Cambrian lime-
by the edge of the great grano- stone (a) truncated by grano-
phyre boss of Ben an Dubhaich. phyre (c) which encloses large
Not only is the dykesharply trun- blocks of the dyke. Torrin, Skye.
cated, but numerous pieces of it,
from 1 to more than 12 inches
in length, are enclosed in the
granophyre.

Mr. Harker informs me that,
while carrying on the Geological
Survey of the district of Strath
(Skye), he has obtained data from
which it may be possible to deter-
mine certain broad distinctions
between dykes older and those
newer than the intrusion of the
granophyres. If these distinctions
are found to hold good, they may
eventually be applicable to the elucidation of the relative ages of
dykes even at a distance from the granophyre, where nothing but
petrographical characters are available as a guide.

Numerous basic dykes traverse the gabbros and granophyre of
St. Kilda. Those in the former group of rocks are more abundant
than those in the latter—a circumstance which is exactly paralleled
among the basic and acid bosses of Skye. It is not improbable

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN HUROPE. 383

that in this remote island a similar difference in age and in petro-
graphical character may be made out between two series of dykes,
one older and the other younger than the granophyre.

The pale colour of the precipices in which the St. Kilda grano-
phyre plunges into the sea gives marked prominence to the dark
ribbon-like streaks which mark the course of the basalt-dykes
through that rock. Moreover, the greater liability of the material
of the dykes to decay causes them to weather into long lines of
notch or recess. Four or five such dykes follow each other in
nearly parallel bands, which slant upward from the sea-level on the
eastern face of the hill known as Conacher to a height of several
hundred feet (fig. 27).'

Fig. 27.—Basalt-vems traversing granophyre. St. Kilda.

Dykes abound in the Faroe Islands, where they cut the basalt-
plateau in the same way as they do that of the Inner Hebrides.
On the whole, however, they do not play, in these northern isles,
the important part which they take in the geology and scenery of
the West of Scotland. I have not had sufficient opportunity to
ascertain whether there is a general direction or system among the
Faroe dykes. In the fjords north of Thorshaven, and again along
the western side of Stromé, many of them show an east-and-west
strike or one from E.N.E. to W.S.W.

Numerous examples of compound dykes, where a central band of
granophyre or spherulitic felsite is flanked on each side by one of
basic material, have recently been met with in Skye by Messrs.
Clough and Harker in the course of the geological survey of that
island. They will be further noticed in the VIIth section of this

paper.

1 This relation of the later dykes to the granophyre was observed here by
Macculloch, ‘ Description of the Western Islands,’ vol. ii. (1819) p. 55.

384 SIR A, GEIKIE ON THE TERIIARY [May 1896,

VI. Tur Inrrusive GaBBRros.

Some of my more recent observations among the gabbros of Skye
have already been communicated to the Society." In conjunction
with my colleague Mr. Teall I have described a remarkable
banded structure traceable in these rocks, wherein the component
minerals have crystallized along different layers in such a manner
as to present a singular resemblance to the arrangement charac-
teristic of many Archean gneisses. Further investigation last
summer has shown me that this banding is extensively developed
in the Cuillin Hills. The mountains that surround the head
of Loch Scavaig and sweep round Loch Coruisk up to the great
crests of Sgurr na Banachdich everywhere display on their bare
black crags a distinct bedded structure.

On the eastern side of Loch Scavaig the rock presents a rudely-
banded character, the bands or beds being piled over each other
from the sea-level up to the summits of the rugged precipices, and
dipping into the hill at angles of 25° to 35°. Abundant dykes
and veins of various basic, intermediate, and acid rocks cut this
structure.. The individual layers here, as at Druim an Eidhne,? are
sometimes wavy and puckered.

Even from a distance the alternating lighter and darker beds can
readily be seen, so that the banded structure, with the variations in
its inclination, may be followed from hill to hill. The regularity of
the arrangement, however, is often less pronounced on closer
inspection. While the gabbro is rudely disposed in thick beds,
indicative of different intrusive sheets or sills, with which the
banding is generally parallel, considerable irregularities may be
observed in the arrangement of the structure of individual sheets.
These sheets may be parallel to each other, and yet, while in some
the banding is tolerably regular in the direction of the planes of
the sheets, in others it is much twisted or inclined at various angles.

On the western side of the Coruisk river the banding is vertical ;
southward from that stream it inclines slightly towards the south,
but soon again becomes vertical, and continues conspicuously so at
the junction of the gabbro with the Torridon Sandstones and the
plateau-basalts on the western side of Loch Scavaig.

In the great corries and ridges of the Cuillin Hills traces of
bedding are generally to be recognized, with later sills injected at
different horizons and in different directions. Instead of being one
great eruptive boss, the gabbro of this district is in reality an
exceedingly complicated network of sills, veins, and dykes. While
the general inclination of the bedding sometimes continues uniform
in direction and amount from one ridge to another, it is apt to
change rapidly, as if the complex assemblage of intruded masses
had been disrupted and had subsided in different directions.

The gabbro overlies the bedded basalts of the plateau all the way
from Glen Brittle to the western side of Loch Scavaig. It then

1 Quart. Journ. Geol]. Soc. vol. 1. (1894) pp. 216, 645.
2 Op. cit. p. 648, and pl. xxvi.

‘Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 385

descends abruptly across these basalts and also across the Torridon
Sandstone, on which they unconformably rest. These two groups
of rocks are not only truncated by the gabbro, but are traversed by
the intricate system of sills, dykes, and veins already referred to.

_ Where it abuts against the sandstones and basalts, the gabbro is
arranged in vertical bands of different mineral composition and
texture. Much of it is remarkably coarse, some bands displaying
pyroxene-crystals more than an inch in length. There is no fine-
grained selyage here indicative of more rapid cooling. So coarse,
indeed, is the rock close up against the sandstone that the junction-
line can hardly be supposed to be the normal contact of the intrusive
rock. This inference is confirmed by the existence of a singular
kind of breccia between the gabbro and the sandstones. It is a
tumultuous mass of fragments of coarse and fine gabbro, Torridon
Sandstone and Shale, and plateau-basalts, imbedded in a pale crys-
talline matrix of fine granular granophyre. Veins from this acid
intrusion run off into the gabbro on the one side as well as into
the Torridon Sandstone on the other. It would seem that this
junction-line has been one of great movement, that the gabbro-
sheets have subsided against a fault-wall of plateau-basalt and
Torridon Sandstone, and that subsequently an intrusion of finely
granular granophyre has come up the fissure, involving in its ascent
fragments of all the materials around.

The rocks for a considerable distance to the south of the gabbro
are intensely altered. The Torridon Sandstone has been so indu-
rated as to pass into a bleached white quartzite, while the shales in-
terstratified with it have been converted into a kind of porcellanite.

But the most interesting alterations are those to be observed in
the plateau-basalts which, at a height of about 300 feet above the
sea, are to be seen in nearly horizontal sheets that lie immediately
on the upturned edges of the Torridon Sandstone. These lavas
have suffered great metamorphism: their alternations of amygda-
loidal and more compact sheets can still be recognized, though their
enclosed amygdules have in places been almost effaced. They show
the dull, indurated, splintery character, with the white weathered
crust, which I formerly described as distinctive of this type of
contact-metamorphism, and are traversed by numerous sills and
veins of gabbro. No large mass of granophyre appears here at the
surface. We can hardly be mistaken in looking upon this altera-
tion as due either to the influence of the main body of the gabbro,
or perhaps more probably to the abundant acid sills, dykes, and
veins, possibly to both causes combined. It must be admitted that
there may be a considerable body of granophyre underneath the
locality, the surface-dykes and veins being indications of its vicinity.

In my former memoir I dwelt upon the remarkable alteration
of the plateau-basalts as they approach the large masses of gabbro
or granophyre.! During the summer of 1895 Mr. Harker, in the

1 Trans. Roy. Soc. Edin. vol. xxxv. (1888) p. 167. Prof. Judd has referred
the alteration of the rocks to solfataric action (Quart. Journ. Geol. Soe. vol. xlvi.
1890, p. 341). I have been unable to detect any evidence of such action. The
alteration is always intimately connected with the presence of intrusive inasses,

386 SIR A. GEIKIE ON THE TERTIARY [May 1896,.

progress of his mapping in the Strath district of Skye, had occasion
to go over a number of the localities (Creaghan Dubha, etc.) cited by
me, and, while corroborating my general conclusions regarding them,
has been able to obtain much fresh evidence regarding the nature
and extent of the metamorphism which the bedded basalts have
undergone. His results will appear in due time, when the survey
of Skye is further advanced. I have submitted to him some slices
cut from typical examples of the altered plateau-basalts as they
approach the gabbro of Loch Scavaig, and he has supplied me with
the subjoined report regarding them :—

‘In hand-specimens the bedded basalts from the neighbourhood
of the gabbro of Loch Scavaig [6613-6618] do not appear very
different from the normal basalts of this region. The most conspi-
cuous secondary mineral is yellowish-green epidote in patches, and
especially in the amygdules.

‘The texture of the rocks varies, and the slices show that the
microstructure also varies, the augite occurring sometimes in small
ophitic plates, sometimes in small rounded granules. The chief
secondary change in the body of the rock is shown by the augite,
which is seen in various stages of conversion to greenish fibrous
hornblende. Some round patches seem also to consist mainly of the
latter mineral, and are probably pseudomorphs after olivine. Here
the little fibres are confusedly matted together, without the paral-
lelism proper to uralite derived from augite. No fresh olivine has
been observed. The felspar and magnetite of the basalts show
little or no sign of metamorphic processes, unless a rather unusual
degree of clearness in the felspar-crystals is to be regarded in that
light.

‘The contents of the metamorphosed amygdules are not always
the same. LEpidote is usually present in some abundance, and in
well-shaped crystals. It has a pale citron tint in the slices, with
marked pleochroism; but a given crystal is not always uniform in
its optical characters. Frequently the interior is pale, and has a
quite low birefringence: this is probably to be regarded as an
intergrowth of zoisite in the epidote, and there are a few distinct
crystals of zoisite seen in some places.

‘In the slide which best exhibits these features | 6613] the crystals
of epidote are in part enwrapped and enclosed by what are doubt-
less zeolitic minerals. At least two of these are to be distinguished.
One, very nearly isotropic, and with a pale-brownish tint, is pro-
bably analcime. Associated with this is a colourless mineral with
partial radiate arrangement and with twin-lamellation; the bi-
refringence is somewhat higher than that of quartz, and the

and it affects indifferently any part of the basalt-plateaux which may chance to
lie next to these masses. The bedded lavas can be traced step by step from
their usual unaltered condition in the plateaux to their metamorphosed state
next to the eruptive rocks. The nature or degree of the metamorphism has
doubtless somewhat varied with the composition and structure of the rocks
affected, and with the character and mass of the eruptive material; but it is
certainly not confined to the older parts of the plateaux nor to any supposed
pre-basaltie group of andesites.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 387

y-axis of optic elasticity makes a small angle with the twin-
line. These characters agree with those of epistilbite. In other
parts of the same large amygdule the epidote-crystals are imbedded
in what seems to be a felspar. This latter mineral is rather
obscure, and twin-lamellation is rarely to be detected ; but it seems
highly probable that felspar has here been developed by meta-
morphic agency at the expense of zeolites which once occupied the
amygdule. I have observed undoubted examples of this in meta-
morphosed basalts from other parts of Skye, e. g. from Creagan
Dubha, near the granophyre-mass of Beinn Dearg.’ The felspar
occurs there in the same fashion, and in the same relation to
epidote [2700, 2701]. In the specimens now described the chief
minerals in the metamorphosed amygdules are those already named :
others occur more sparingly, associated with them. In some cases
there is a grass-green, strongly pleochroic, actinolitic hornblende,
accompanied by a little iron pyrites [6615].

‘Epidote and various hornblendic and augitic minerals are
characteristic products in the metamorphism of amygdaloidal basalts
in other regions: felspar with this mode of occurrence I have not
seen except in Skye, where it seems to connect itself naturally with
the abundance of zeolites in the amygdules of the non-metamorphosed
lavas. It is to be observed that in these basalts from Loch Scavaig
the alteration is shown especially in the amygdules, the body of the
rock not being greatly affected: this indicates a not very advanced
stage of metamorphism. The production of uralitic hornblende,
rather than brown mica, from the augite and its decomposition-
products seems to be characteristic of the metamorphism of basaltic
as distinguished from andesitic rocks, and is well illustrated by com-
parison of the two sets of lavas near the Shap Granite.’?

A re-examination of parts of the gabbro mountains of Rum has
shown me that, though in a less marked degree than in Skye, the
same banded structure may be detected in the thick beds or sills of
which these eminences are composed. The remarkably schist-like
bed of troctolite formerly described by me* lies between more
massive sheets that show a much ruder parallel structure. The
whole mountain of Allival overlying this troctolite is built up of
successive parallel sheets of gabbro, among which banding is of
frequent occurrence, the layers varying from less than an inch to a
foot or more in breadth, and lying parallel to each other and to the
upper and under surfaces of the sheets in which they occur. An
occasional example of curvature in the banding may be observed.

Compared with the gabbros of the Cuillin Hills, those of Rum
display a similar but less definite aggregation of their component
minerals in definite layers or bands. In particular, the pyroxene
and olivine, either separately or together, are crowded along parti-
cular bands of darker hue, while the paler bands between them are
composed chiefly of felspar. The crystals or crystalline kernels are

1 Compare Trans. Roy. Soc. Edinb. vol. xxxv. (1888) p. 166.
2 Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 361.
3 Trans. Roy. Soc, Edinb. vol. xxxv. (1888) p, 123; Quart. Journ. Geol, Soc.
vol. 1. (1894) p. 649. .

Q.J.G.8. No. 206. 2p

388 SIR A. GEIKIE ON THE TERTIARY [May 1896,

sometimes an inch in diameter, so that when closely grouped along
particular layers they give rise to strikingly coarse-grained varieties
of rock. Magnetite, on the whole, is rather less conspicuous than in
the Cuillin gabbro; at least, it 1s not so prominently aggregated in
special layers.

So rude is the parallel structure in these rocks of Rum that,
although quite recognizable on a weathered surface where the con-
stituent minerals are revealed by the way in which they respec-
tively decay, it is often hardly to be detected on a freshly-broken _
exposure.

The western and more rugged part of the island of St. Kilda’ is
built up of various gabbros, dolerites, and basalts, traversed by
dykes and veins of similar material. The gabbros include rocks of
coarse, medium, and fine grain, like those of Skye, which lie in
sheets or sills, but also apparently in large irregularly-shaped
masses. In one or two places I noticed a faint banding, but my
opportunities of studying these rocks were cut short by a change
of weather which necessitated an abrupt departure, there being no
safe anchorage at the island. I sailed round the coast, however,
near enough to form a good idea of the general structure of the
rock. Like the corresponding masses of the Cuillin Hills, the
St. Kilda gabbro arrests attention by its singular blackness of tone,
varied by its yellow coating of lichens and its grey crust of
weathering, while its occasional slopes of débris are covered with a
thick bright-green carpet of turf formed of matted sea-pink.

While the gabbros of St. Kilda are not a mere uniform boss, but
rather a series of sills and irregular masses which have been
successively injected into each other, they have subsequently been
cut through by the basalt-dykes and veins already noticed. These,
which are sometimes as abundant as in the gabbro of the Cuillin
Hills, traverse the rock at all angles, and, as they generally weather
faster than it does, they give rise to deep clefts which ascend the
precipices, occasioning sea-caves below and sharp notches on the
crests above. :

These scenic features, so indicative of the geological structure
that causes them, are specially well seen on the western face of the
Dune or south-western promontory of the island, and likewise in
the strangely rifted precipices to the north. They are, however,
still more impressively displayed around the naked walls of the
neighbouring islet of Borrera (1000 feet high), which consists entirely
of gabbro pierced with dykes, and in its marvellous combination of
spiry ridges, deep straight gullies, and splintered crests, reminds one
at every turn of the scenery of Blaven and the Cuillin Hills.

Nowhere in St. Kilda or its dependent islets can any certain
trace be obtained of a rock more ancient than the gabbros. So
great has been the denudation that the eruptive core of this volcanic
district has been reduced merely to a few scattered islets. If, as is
probable, this core was once surrounded and covered by a plateau
of basalt, no fragment of such a plateau remains, unless we may be

1 For references to published information on the geology of this island
see pp. 389, 390.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 389

allowed to recognize it among some of the basalt-sheets included
among the gabbros.

Like their counterparts in the Inner Hebrides, these rocks have
not only been traversed by basic dykes, but have been invaded by a
large mass of granophyre. The junction of the acid and basic

- materials repeats the evidence already cited from Mull, Rum, and

Skye, and proves beyond all question that the acid rock is the
younger of the two. The characters of this junction will be given
in the next section of this paper.

It is interesting to observe that, while in St. Kilda no relic of any
basaltic plateau has been preserved, in the Faroe Islands, on the
other hand, no sign has been revealed by denudation that the
volcanic plateau of that region has any eruptive core of gabbro or
of granophyre. During my cruises round these islands and through
their channels, I was ever on the outlook for any difference in
topography that might indicate the presence of some eruptive boss
like the gabbro- and granophyre-masses of the Inner Hebrides.
But nothing of that nature could be discerned. Everywhere the
long level lines of the bedded basalts mounted up to the crests of
the ridges and the tops of the highest peaks. Though I cannot
assert that no intrusions of zgabbro or of granophyre exist among
the Faroe Islands, I feel confident that any such masses which
may occur must be of quite insignificant dimensions, and do not
make the important feature in geology and topography which they
do among the Inner Hebrides.

VII. T'an Granopoyre INTRUSIONS.

Having recently brought the subject of the Tertiary granophyres
before the Society,’ I shall content myself in the present paper
with an account of some additional examples of their occurrence
and of their relations to the other members of the volcanic series.

St. Kilda supplies fresh evidence of much interest in this part
of the volcanic history. The visitor, in approaching the island,
especially from the southern or northern side, will notice the same
two strongly contrasted topographical features as those that are so
well exhibited in the centre of Skye. Along the western side rise
the black rugged crags of gabbro. The eastern precipices are pale in
colour, and are capped by rounded or conical hills, which towards
the interior send down long screes of grey or russet-coloured
débris. Their forms are so like those of the Red Hills of Skye
that the geologist recognizes their true nature and respective limits,
even before setting foot on them.

To Macculloch we are indebted for the first good description of
the rocks of St. Kilda.” He clearly identified the pale rock of the
eastern half of the island with the ‘syenite’ or granophyre of Skye,
and he further remarked that it presented much resemblance to
some parts of the granite of Arran. He observed ‘ fragments of
trap penetrated by veins of syenite,’ but he did not see these

1 Quart. Journ. Geol. Soc. vol. 1. (1894) pp. 212-229.

2 * Description of the Western Islands,’ vol. ii. (1819) p. 54.
2p 2

390 SIR A. GEIKIE ON THE TERTIARY [May 1896,

rocks in place, and, in spite of their apparent testimony to the
posteriority of the acid intrusions, he was inclined to believe that:
the veins were not real veins, but that the ‘ trap’ and ‘ syenite’ had a
common origin and would be found to pass into each other, as he
thought also occurred in Mull and Rum. In recent years
Mr. Alexander Ross has Saemed St. Kilda and published an excellent
account of its geology.’ He collected specimens illustrating the
varieties of gabbro, dolerite, and basalt, and showing the intrusion
of the acid into the basic rocks. He was disposed to believe the.
‘granite’ to be of younger date than the gabbros, but left the
question open for further consideration.

The acid rock which forms the eastern side of this island, variously
termed ‘syenite’ and ‘ granite,’ weathers in thick bed-like sheets,
divided by transverse joints into large quadrangular blocks, like
many granites. On closer inspection it is found to resemble still
more precisely the acid rocks of the Inner Hebrides. It possesses
the same drusy micropegmatitic structure as the granophyres of Skye,
Rum, and Mull. The ferro-magnesian constituents are present in
small quantity, hence the pale hue of the stone. The quartz and
felspar project in well-terminated crystals into the drusy cavities,
which are sometimes further adorned with delicate tufts of clear,
crystallized epidote. In many respects the rock resembles the
young granites of Arran and the Mourne Mountains.

Mr. Harker’s notes on the microscopic structure of this granophyre
are as follows:—‘The prevailing felspar is orthoclase, often very
turbid from secondary products. Even what appear to be distinct
crystals are sometimes seen in the slices to be invaded in the margin
by quartz in rough micrographic intergrowths, and much of the finer
intergrowth occurs as a fringe to the crystals, In this case the
felspar of the micropegmatite can often be verified to be in crystalline
continuity with the crystal which has served as a nucleus [6624].
Quartz occurs in distinct. crystals and grains as well as in the micro-
pegmatite. There is a more granitoid variety of the rock, in which
only a very rude approach to micrographic intergrowths is seen
[6623]. In both varieties there is but little trace of any ferro-
magnesian mineral; the more typical granophyre has what seems
to be destroyed augite, while the granitoid rock contains a little
deep-brown biotite. Scattered crystal-grains of magnetite occur
in both.’

Narrow ribbon-like veins of a finer material, sometimes only an inch
in breadth, traverse the ordinary granophyre. Similar veins run

* Brit. Assoc. Rep. 1885 (Aberdeen meeting). p. se et a much fuller paper
in the Proe. Inverness Field Club, vol. iii. (1884) p In this latter paper
a letter from Prof. Judd is quoted, in which he ee that the rock supposed
to be. granite ‘is seen under the microscope to be a quite different rock—a
quartz-diorite,’ p. 78. Some of the specimens from St. Kilda collected by
Mr. Ross were exhibited at the meeting of this Society on January 25th, 1893.
With regard to these, Prof. Judd, in the course of the discussion on his paper
on ‘Inclusions of Tertiary Granite in the Gabbro of the Cuillin Hills,’
remarked :—‘ They show a dark rock traversed by veins of a light one, but. the
dark rock is not a gabbro, and the light rock i is not a | granite,’ ‘Quart. Journ.
Geol. Soc. yale alls (1893) p. 198.

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 391

through the rock of the Red Hills in Skye; they are sharply defined
from the enclosing rock, as if the latter had already solidified before
their intrusion.

With regard to the microscopic structure of some thin slices
prepared from these veins, Mr. Harker remarks that ‘the material
of the veins is of a type intermediate between granophyre and
microgranite [6622, 6623]. The chief bulk is a finely granular
aggregate of quartz and felspar, the latter very turbid ; but in this
» aggregate are imbedded numerous patches of micropegmatite, often
of perfect and delicate structure. These areas of micropegmatite
show some approach to a radiate or rudely spherulitic structure,
and, in some cases, are clustered round acrystal of felspar or quartz.
Some granules of magnetite and rare flakes of brown biotite are the
only other constituents of the rock. Although they must be of
somewhat later date, there is evidently nothing in the petrographical
characters of these fine-textured veins to separate them widely from
the ordinary granophyres of the region.’

These veins may be compared with the spherulitic dyke which
traverses the granophyre of Meall Dearg at the head of Glen
Sligachan, and which, though undoubtedly somewhat later than the
rock that contains it, yet presents the very same structures as are
visible at the margin of that rock.’ The material of this dyke, and
of the finer veins of St. Kilda and the Red Hills, probably belongs
to a later period of protrusion from a deeper unconsolidated portion
of the same acid magma as that which at first supplied the general
body of granophyre.

Undoubtedly the most interesting feature in the granophyre of
St. Kilda is its junction with the mass of basic rock to the west of
it. It requires no close search to find in situ the dark rock with
acid veins of which Macculloch found scattered fragments. The
line of junction between the basic and acid masses runs across the
island from the western side of the chief bay to the northern coast,
where it is exposed in a line of high cliffs.

The beach to the west of the landing-place in the bay is strewn
with blocks of various dark, finely crystalline basic rocks, traversed
by pale veins of granophyre. At the western end of the shingle,
the rocks are met with in places forming a line of low cliff and a
rugged foreshore. The basic rock consists of various gabbros and
basalts of rather fine grain, profusely traversed with veins of white
granophyre. Some of these veins are 2 feet or more in breadth,
and, when of that size, show the distinctive granular texture and
drusy structure of the main part of the acid rock. But from these
dimensions they can be traced through every stage of diminution
until they become mere threads. When they are only an inch or
two broad they assume a finely granular texture, like that of the
veins which run through the body of the granophyre.

The amount of injected material in the dark basic rocks is here
and there so great as to form a kind of breccia (fig. 28, p. 392),
which, trom the contrast of tone between its two constituents, makes
a conspicuous object on the shore. The enclosed fragments are of

* Quart. Journ. Geol. Soc. vol. 1. (1894) p. 220.

392 SIR A. GEIKIE ON THE TERTIARY [May 1806,

all sizes from mere grains up to blocks a foot or more in length.
They are generally angular, like rock-chips from a quarry. The
granophyre here and there assumes a darker or greener tint, as if
it had dissolved and absorbed some portion of the older rock.

Fig. 28.—Pale granophyre injected into dark basalt. St. Kilda.
[From a photograph by Col. Evans. ]

Though closer in grain where it comes in contact with the gabbro,
the granophyre never assumes any vitreous or distinctly spherulitic
textures along its margin. A series of thin slices prepared from
my specimens has been examined for me by Mr. Harker, who has
furnished the following notes regarding them :—‘ The basalt traversed
by the granophyre is a fine-textured variety, with small porphyritic
felspars. ‘These latter seem to be usually unaltered, retaining the
glass-cavities which in some of the crystals are abundant. The
groundmass, however, shows minerals of metamorphic origin which
must be derived mainly from the original augite. A brown mica is
the most conspicuous; but with it are associated some brownish-
green hornblende and certain chloritie and perhaps serpentinous
substances. It is chiefly near the margin of a fragment of basalt
that the mica gives place to these minerals. The basalt still retains
plenty of unaltered granules of augite in the central parts of a
fragment. It is not certain that the secondary minerals named
come exclusively from the augite of the basalt; judging from their
form and mode of occurrence I should say that they may in part
have replaced olivine or even rhombic pyroxene. |

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 393

‘The acid rock, though styled granophyre above, belongs to a
granitoid variety of that group of rocks, and has but little indication
of micrographic structures. Compared with the other granophyres
from St. Kilda, sliced and examined, these examples show a less
acid composition. This is expressed mineralogically in the presence
of a somewhat larger proportion of ferro-magnesian minerals and
of soda-lime felspar. ‘These features might indeed be matched in
many normal granophyres among the Western Isles, but in the
present case it can hardly be doubted that they are to be explained,
at least in some degree, by the acid magma having taken up a
certain amount of material from the basalt. Many of these Tertiary
granophyres have undoubtedly been modified by the incorporation
of pieces of basalt and gabbro, and a collection made in the Strath
district of Skye will furnish examples for future study. Prof. Sollas’s
description of similar phenomena in the Carlingford district has
already proved the importance of this kind of action.’ In the
present instance, both brown mica and hornblende occur plentifully
in the granophyre, and especially round the basalt-fragments. This
latter point is conclusive as to the derivation of the basic material,
and further proves a certain degree of viscosity in the acid magma
at the time of its intrusion.’

On the northern side of St. Kilda the junction-line of the granophyre
runs up the cliffs, abundant pale veins of the acid material striking
off from the main body of the rock and traversing the dark gabbros.

The testimony of the rocks of St. Kilda to the posteriority of
the granophyre to the gabbros and basalts is thus clear and emphatic.
It entirely confirms my published observations regarding the
order of sequence of these rocks in Mull, Rum, and Skye. But the
St. Kilda sections display, even more strikingly than can be usually
seen in these islands, the intricate network of veins which proceed
from the granophyre and the shattered condition of the basic rocks
which these veins penetrate.

I have already alluded to the remarkable association of acid and
basic material in numerous dykes as well as in some sills in the
district of Strath in Skye. I formerly described some examples of
this association from that district,’ and many more have recently
been observed and mapped by Mr. Clough and Mr. Harker during
the progress of the Geological Survey. The conjunction commonly
shows a central and thicker band of granophyre or spherulitic felsite
with two thinner parallel bands of some dark intermediate or basic
rock. ‘his triple arrangement occurs both in dykes and sills.

As an illustration of the association of the two kinds of rock in
dykes I may cite the example which appears on the southern edge
of the Market Stance of Broadford (fig. 29, p. 394). Here the charac-
teristic triple arrangement is typically developed. A central light-
coloured band, about 8 to 10 feet broad, consists of a spherulitic
granophyre in which the spherulites are crowded together and project
from the weathered surface like peas, though they do not here
show the curious rod-like aggregation so marked in some other

1 Trans. Roy. Irish Acad. vol. xxx. (1894) pp. 477-512.
? Trans. Roy. Soc. Edinb. vol. xxxv. (1888) p. 174.

394 | SIR A. GEIKIE ON THE TERTIARY [May 1896,

dykes. On either side of this acid centre a narrow basnlt-dyke
intervenes as a wall, next to the Torridon Sandstone which here
forms the country-rock.

- In this instance, and generally throughout the district, there is
nothing to indicate that the different bands of the dyke have any
relation to each other

as connected uprises of
material from the same wis: 22:~ Compound dyke. Market

original magma which was Stance, Broadford, Skye.
undergoing a process of ta aalfe sigh rede be HES
differentiation beneath the ee ES
terrestrial crust. On the Ree

contrary, the several parts a
of each dyke areas distinctly ¢ AE
marked off from each other es
as they could have been
had they been injected at
widely separated intervals
of voleanic activity. a. Granophyre; 06. Basalt; ec. Torri-

The same indication of doh: sandstone:
an independent origin is
displayed by the rocks when they form compound sills, with a
thick central sheet of acid material overlain and underlain by some
more basic rock. I have shown that the posteriority of the acid
sill may sometimes be demonstrated by its sending out veins into
the darker sill above or below it... But a more striking proof of
the independence of the two kinds of rock may be seen at Suishnish
Point, in the Isle of Raasay (fig. 30). Here the Pabba Shales of
the Lower Lias (a a) are surmounted by a sheet of granophyre (6), of
which the top has been removed by denudation. This rock occupies
about 5 square miles inthe southern half of the island, where it has
recently been mapped by Mr. H. B. Woodward for the Geological
Survey. It has been intruded across the Jurassic Series, a large
part of its mass coming in irregularly about the top of the thick
white sandstones of the Inferior Oolite. But it descends beneath
the Secondary rocks altogether, and in some places intervenes
between the base of the Intra-Liassic conglomerates and the Torridon
Sandstone.

The central portions of this Raasay granophyre possess the
ordinary structures of the corresponding rocks in Skye. They show
a fine crystalline-granular micropegmatitic base, through which
large felspars and quartzes are dispersed. But at the upper and
under junctions with the sedimentary rocks beautiful spherulitic
structures are developed. This is well seen on the shore near
the Point of Suishnish, where, below the Liassic limestones, the top
of the granophyre appears, and where its bottom is seen to lie on
the Torridon Sandstone.

Where the eruptive rock rests on the Pabba Shales, a basalt-
dyke which rises through these strata turns abruptly at the base
of the acid rock and then pursues its course to one side as a sill (¢)

1 Trans. Roy. Soc, Edinb. vol. xxxy. (1888) p. 174.

Vol. 52.] BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 395

between the granophyre and the shales. There can be little doubt
that this intrusion is later than the granophyre. We have here a
basic sill interposed at the bottom of the acid sheet; but in this
case we can connect the sill with the actual fissure up which its
molten material was impelled.

Fig. 30.—Section of granophyre-sill resting on Lower Lias shales,
with a dyke of basalt passing laterully into a sill.

Some remarkable illustrations of the threefold arrangement of
compound sills have recently been observed and mapped by Mr. Harker
in the Broadford district, one of great interest occurring on the
shore at Irishman’s Point in Broadford Bay.

VIIT. Mopern Votcanic Action 1n IcELAND, AS ILLUSTRATIVE OF THE
History oF THE BASALT-PLATEAUX OF NORTH-WESTERN EvROpPE.

Beyond the Faroe Islands, at the further end of the Wyville-
Thomson ridge, which stretches across the bottom of that part of
the Atlantic Ocean, another basalt-plateau rises in Iceland, pre-
senting many of the familiar characters of those described in this
paper, and probably belonging to the same geological period. The
bottom of these Icelandic Tertiary basalts is everywhere concealed
under the sea. Yet their visible portion shows them to be probably
more than 3000 metres in thickness.

An especial interest belongs to this Icelandic plateau because
volcanic action is still vigorous upon it at the present day. A long
series of eruptions has taken place there since the Glacial Period.
There were likewise abundant pre-glacial eruptions. So far indeed as
we know, there is no evidence of any important cessation of the
subterranean activity since Tertiary time.’ The existing volcanic
pheuomena may with probability be regarded as the survival of
those which were so widely manifested over the Icelandic area and
the North-west of Europe in the older Tertiary ages. A careful
study of them may therefore be expected to throw light on the
history of the Tertiary basaltic plateaux; while, on the other hand,
the thorough dissection of these plateaux by the denuding agencies

1 See Johnston-Lavis, Scottish Geogr. Mag. 1895, p. 442.

396 SIR A. GEIKIE ON THE TERTIARY | [May 1896,

will not improbably be found to explain some parts of the subter-
ranean mechanism of the Icelandic volcanoes.

In calling attention to some of the more obvious analogies which
may be traced between the modern and the ancient volcanoes, I am
more particularly indebted to the excellent memoirs of the resident
Icelandic geologist Mr. Th. Thoroddsen, who has examined go large
a part of the island.!. The account given by A. Helland of the Laki
craters has likewise been of much service to me.2 Among otber
_recent observers I may cite Dr. Tempest Anderson,? who has made
himself familiar with extensive tracts of Iceland, and Dr. Johnston-
Lavis, who has published the narrative of a journey in company
with him.*

It is a mistake to suppose that the Icelandic volcanoes are
generally built on the plan of such mountains as Vesuvius or Etna.
Evidently Mr. Thoroddsen can hardly repress his impatience on find-
ing these two Italian cones cited in almost every handbook of geology
as types of modern voleanoes and their operations. The regular
volcanic cone composed of alternations of lavas and tuffs hardly
occurs in Iceland at all. The fundamental feature in the Icelandic
eruptions is the production of fissures which reach the surface and
discharge streams of lava from many points.

Two systems of fissures appear to be specially marked, one running
from south-west to north-east, the other from south to north.’
Hekla and Laki belong to the former. The dislocations have often
followed the boundaries of the ‘ horsts’ or solid blocks of country
which have withstood terrestrial displacement. The vast outbursts
of Odadahraun and Myvatn have almost all issued from fissures of
that nature.

The violent eruption of 1875 in Askja found its exit at the
intersection of two lines of fissure. Many large fissures were opened
on the surface in a nearly north-and-south direction, which could be
followed for 80 kilometres. Some of them became the theatre of
intense volcanic activity.°

Many lines of fissure are traceable at the surface as clefts or
‘gjas,’ that run nearly straight for long distances, with a width
of 1 to 3 yards, and of unknown depth.’ Occasionally a fissure

1 See in particular his paper on the volcanoes of N.H. Iceland (Bihang till k.
Svensk. Vet. Akad. Handl. vol. xiv. pt. ii. no. 5, 1888) and that on Snaefell and
Faxebugt in the south-west of the island (op. cz¢. vol. xvii. pt. 11. no. 2, 1891);
also papers in the Dansk. Geografisk. Tidsskrift, vols. xii., xiii. (1893-95), and
in the Verhandl. Gesellsch. Erdkunde zu Berlin, 1894 & 1895.

2 ‘Lakis Kratere og Lavastromme,’ Universitetsprogram, Christiania, 1885.
See Mr. Thoroddsen’s remarks on this paper, Verhandl. Gesellsch. Erdk.
Berlin, 1894, p. 289.

8 Brit. Assoc. Rep. 1894 (Oxford meeting), p. 650.

4 Johnston-Lavis, Scot. Geogr. Mag. 1895.

5 In the Snaefell promontory they run nearly east and west, Thoroddsen,
Bi hang Svensk. Vet. Akad. Handl. vol. xvii. pt. ii. no. 2, p. 91.

6 Thoroddsen, op. cit. vol. xiv. pt. ii. no. 5, p. 63.

7 On the various modes of origin of these chasms, see Tempest Anderson,
Brit. Assoc. Rep. 1894, p. 650. Mr. Thoroddsen describes a fissure in the
south of Iceland running N.E. for 30 kilometres, with a depth of 130 to 200

metres. It has discharged three great lava-streams, covering a total area of
693 square kilometres.

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 397

has not been continuously opened to the surface. An interesting
example of such intermittent chasms is supplied by the great rent
which gave forth the enormous volume of lava in 1783. The moun-
tain of Laki, composed of palagonite-tuff, stands on the line of the
dislocation, but has not been entirely ruptured. The fissure has
closed up beneath the mountain, a short distance above the bottom
of the slope, as is shown by the position of a couple of small
craters.’

Some fissures have remained mere open chasms without any
discharge of volcanic material; others have served as passages for
the escape of lava and the ejection of loose slags and cinders.”

In some instances, according to Mr. Thoroddsen, lava wells out
from the whole length of a fissure without giving rise to the forma-
tion of cones, the molten material issuing either from one or from
both sides, sometimes flowing out tranquilly, but more usually
giving rise to long ramparts of slags and blocks of lava piled up on
either side. In the great majority of cases, however, a row of cones
is formed along the line of the open fissure. Thus, on the Laki
fissure, which runs for about 20 miles in a north-easterly direction,
the cones amount to some hundreds in number. Hekla itself appears
to have been built up along a main fissure, with parallel subsidiary
rents on which rows of cones have been formed.”

The cones consist generally of slags, cinders, and blocks of lava.
According to Mr. Helland’s observations, along the marvellous line
of the Laki fissure they are on the whole not quite circular but
oblong, their major axis coinciding with the line of the chasm on
which they have been piled up. In many places they are exceed-
ingly irregular in form, changes in the direction of outflow of lava
or of escape of steam having caused the cones partially to efface
each other.

As regards their size, the cones present a wide range. Some of
them are only a few yards in diameter, others several hundred
yards. Generally they are comparatively low mounds. On the
Laki fissure some are only a couple of yards high ; the majority are
much less than 50 yards in height, and hardly one is as much as
100 yards.* And yet these little monticules, as Mr. Helland
remarks, represent the pipes from which milliards of cubic metres
of lava have issued. While other European volcanoes form con-
spicuous features in the landscape, the Icelandic volcanoes of the
Laki district, from which the vastest floods of lava have issued in
modern times, are so low that they might escape notice unless they
were actually sought for.’

As they have generally arisen along lines of fissure, the cones are
for the most part ranged in rows. The hundreds of cones that

? A. Helland, ‘ Lakis Kratere og Lavastrémme,’ p. 25.

? Mr. Thoroddsen has observed that in the Reykjanes peninsula, in the S.W.
of Iceland, by the subsidence of one side of a fissure, a row of four craters has
been cut through, leaving their segments perched upon the upper side (‘ Globus,’
vol. lxix. no. 5).

8 Johnston-Lavis, op. cit. p. 457.

* Mr. Thoroddsen, however, states that there are about 100 between 20 and
100 metres in height. 5 A, Helland, op. cit. p. 27.

398 SIR A. GEIKIE ON THE TERTIARY © [May 1896,

mark the line of the Laki fissure present an extraordinary picture
of volcanic energy of this type. In other instances the cones occur
in groups, though this distribution may have arisen from the
irregular uprise of scattered vents along a series of parallel fissures.
Thus to the north-east of Laki a series of old cones, entirely sur-
rounded by the lavas of 1783, lie in groups, the most northerly of
which consists of about ‘one hundred exceedingly small craters that
have sent out streams of lava towards the north-north-east.!

It would appear from Mr. Helland’s observations that the same
fissure has sometimes been made use of at more than one period of
eruption. He describes some old craters on the line of the Laki
fissure, which had been active long before the outbreak of 1783.7

When the lava issues from fissures it is in such a condition of
plasticity that it can be drawn out into threads and spun into ropes.
When the slope over which it flows is steep it often splits up into
blocks on the surface. Where the ground is flat the lava spreads
out uniformly on all sides, forming wide plains as. level as a floor.
Thus the vast lava-desert of Odadahraun covers a plain 3640
square kilometres in area, or, if the small lava-streams north from
Vatnajokull be included, 4390 square kilometres. This vast flood
of lava (about 1700 English square miles in extent) would, accord-
ing to Mr. Thoroddsen, cover Denmark to a depth of 16 feet. The
whole of this enormous discharge has been given forth from more
than twenty vents situated for the most part on parallel fissures.

Not less striking is the picture of fissure-eruption to be met with
at Laki—the scene of the great lava-floods of 1783. ‘Conceive
now, says Mr. Helland, ‘ these hundreds of craters, or, as they are
called by the Icelanders, “ borge,”’ lying one behind another in a long
row; every one of them having sent out two or more streams of
lava, now to the one side, now to the other. Understand further
‘that these streams merge into each other, so as to flow wholly
round the cones and form fields of lava miles in width, which, lke
vast frozen floods, flow down to the country districts, and you may
form some idea of this remarkable region.’ *

In the course of time the successive streams of lava poured out
upon one of these wide volcanic plains gradually increase the height
of the ground, while preserving its generally level aspect. The
loose slag-cones of earlier eruptions are effaced or swallowed up, as
one lava-stream follows another. Eventually, when, by the opera-
tion of running water or by fissure and subsidence, transverse
sections are cut through these laya-sheets, the observer can gene-

1 A. Helland, ‘ Lakis Kratere og Lavastromme,’ p. 25. ? Op. cit. p. 26.

3 Op. cit. p. 24. Mr. Helland allows an average thickness of 30 metres for
the mass of lava which issued in two streams, one §0 kilometres (nearly 50
miles), the other 45 kilometres (about 28 miles) long. He estimates the total
volume of lava discharged in the 1783 eruption at 27 milliards of cubie metres,
equal to a block 10 kilometres (6 miles 376 yards) long, 5 kilometres (8 miles
188 yards) broad, and 540 metres (1771 feet) high ; op. cit. p. 31. Mr. Tho-
roddsen remarks that the older estimates of the volume of lava discharged by
this eruption have been greatly exaggerated. He puts the area covered by lava
at 565 square kilometres, and the contents at 1234 cubic kilometres (Verhand].
Gesellsch, Erdk. Berlin, 1894, p. 296).

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 399

rally notice only horizontal beds of lava piled one above another,
including the dykes connected with them and intercalated masses of
loose slag, that remain as relics of the old craters.

In some places the lava has gradualiy built up upon its parent
fissure an enormous dome, having a gentle inclination in every
direction, as may be seen especially in the district between Floderne
Skjalfanafljot and Jokulsa. Most of the large volcanic piles of
North Iceland are of this nature. The highest of them are 1209
and 1491 metres high by from 6 to 15 kilometres in diameter.
The elliptical crater of the highest of these eminences measures 1100
by 380 metres."

There is still another feature of the Icelandic volcanic regions
which may be cited as an interesting parallel to the sequence of
eruptive discharges among the Inner Hebrides. While the main
mass of the lavas is more or less basic, many of them being true
basalts, they have been at different times pierced by intrusions
and outflows of much more acid Jiparites, and even of granophyre.
Examples of these rocks of post-glacial age have recently been
traced on the ground by Thoroddsen,* and their petrographical
characters have been studied by Backstrom.’ The wide distribution
of such rocks all over the island, their occurrence in isolated bosses
among the more basic lavas, and their remarkable internal structures
have been noted by several observers.*

It will thus be seen how entirely the modern volcanic eruptions
of Iceland agree with the phenomena presented by our Tertiary
basalt-plateaux. It is to the Icelandic type of fissure-eruptions, and
not to great central composite cones like Vesuvius or Etna, that we
must look for the modern analogies that will best serve as commen-
tary and explanation for the latest chapter in the long volcanic
history of the British Isles.

IX. Tue FAvtts or THE PLATEAUX,

There can be no doubt that considerable alterations of level have
taken place over the volcanic areas of North-western Europe since
the eruptions that produced the basalt-plateaux. The mere fact
that in many places the lower members of these terrestrial lavas
have been submerged under the sea may be taken to prove a subsi-
dence there since older Tertiary time. Along the western coast of
Skye this depression is well shown by the almost entire conceal-
ment of the bottom of the plateau under the Atlantic. In the Faroe
Isles the subsidence has advanced still further, for not a trace of the

: oa Bihang till Svensk. Vet. Akad. Handl. vol. xiv. pt. ii. no. 5,
ee Geol. Foren. Stockholm Férhandl, vol. xiii. (1891) p. 609; Bihang Svensk.
Vet. Akad. Handl. vol. xvii. (1891) pt. ii. p.21; Dansk. Geogr. Tidsskr. vol. xiii.
(1895). He has also found peaks of gabbro and boulders of the same rock
brought down from the Vatnajékull. The gabbro rests upon basalt, seems to
be associated with granophyres, and is cut by dykes of liparite. It is regarded
by Mr. Thoroddsen as belonging to the older Tertiary series and to occur pro-
bably in the same way as the gabbro of Mull (op. cit. p. 35).

' 8 Geol. Foren. Stockholm Forhandl. vol. xiii. (1891) p. 637.

4 See in particular OC. W. Schmnidt, Zeitschr. Deutsch. geol. Gesellsch,
vol. xxxvii. (1885) p. 737.

400 SIR A. GEIKIE ON THE TERTIARY [May 1896,

underlying platform on which the basalts rest remains above water.
In Iceland, too, the complete submergence of the base of the
Tertiary volcanic sheets points to the widespread subsidence of that
region.

Another strong argument in favour of considerable subsidence may
be derived from a comparison of the submarine topography with that
of the tracts above sea-level. It is obvious that the same forms of
contour as those which are conspicuous on the land are prolonged
under the Atlantic. If we are correct in regarding the valleys as
great lines of subaerial erosion, their prolongations as fjords and
submarine troughs must be regarded as having had a similar origin.
We can thus carry down the surface of erosion several hundred feet
lower than the line along which it disappears under the waves.

I know no locality where this kind of reasoning is so impressively
enforced upon the mind as the western end of the Scuir of Kigg. The
old river-bed and its pitchstone terminate abruptly at the top of a
great precipice. Assuredly they must once have continued much
farther westward, as well as the sheets of basalt that form the main
part of the cliff. Yet the sea in front of this truncated face of rock
rapidly deepens to fully 500 feet in some places. Had any such
hollow existed in the volcanic period it would have been filled up
by the long-continued outflowings of basalt. We can only account
for this submarine topography by regarding it as having been
carved out, together with the topography of the land, at a time when
the level of the latter was at least 500 feet higher than it is now.

The subsidence which is thus indicated along the whole of the
North-west of Europe probably varied in amount from one region
to another. We seem to have traces of such an inequality in the
varying inclinations of different segments of the basalt-plateaux. The
angles of inclination are almost always gentle, but they differ so much
in direction from island to island, and even among the districts of
the same island, as to indicate that certain portions of the volcanic
plain sank rather more than other portions.

Thus in the Faroe Islands, where the bare cliffs allow the varying
angles of inclination to be easily determined, a general gentle dip of
the basalts in a south-easterly direction has been noted by previous
observers. This inclination, however, is replaced among the southern
islands by an equally gentle dip towards the north-east. The
centre of depression would thus seem to lie somewhere about Sando
and Skuo. The highest angle of inclination which I noticed any-
where was at Myggenaes, where the basalts dip E.S.E. at about 15°.

Though I have not observed any features among the basalt-
plateaux that can be compared to the remarkable rifts and sub-
sidences of Iceland, it can be shown that these piles of volcanic
material have undoubtedly been fractured, and that portions of them
have subsided along these lines of dislocation. Careful examination
of the basalt-escarpments of the Inner Hebrides discloses the
existence of numerous faults which, though generally of small
displacement, nevertheless completely break the continuity of all
the rocks in a precipice of 700 or 1000 feet in height. Not infre-

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 401

quently such dislocations give rise to clefts in the cliffs. Some
good illustrations of this feature may be noticed on the northern side
of the island of Canna, where the highest part of the precipice has
been fissured by a series of dislocations, having a hade towards the
west and a throw which may in some cases amount to about 20 or
25 feet. The cumulative effect of this system of faulting, combined
with a gentle westerly dip, is to bring down to the sea-level
the upper band of conglomerate which farther east lies at the
top of the cliff. Again, the basalt-escarpment on the western side
of Skye, from Dunvegan Head to Loch Eynort, is traversed by a
number of small faults. On the eastern side of Skye and in Raasay
a series of faults, some of them having perhaps a throw of several
hundred feet, has been mapped by Mr. H. B. Woodward.

_ The largest dislocation observed by me among the fragments of
the basalt-plateaux is that which runs at the back of the Morven
outlier, in the west of Argyleshire.’ It runs from the head of Loch
Aline to the mouth of Loch Sunart along the line of valley that
contains the salt-water fjord Loch Teacus and the freshwater lakes
Loch Durinemast and Loch Arienas. While the Cretaceous deposits
and the bottom of their overlying basalts rise but little above the
sea-level on the south-western side of this line, they are perched as
outliers on hilltops on the north-eastern side, where they rise to 1300
feet above the sea. The amount of vertical displacement here
probably exceeds 1000 feet. The fault runs in a north-westerly
direction, and has obviously been the guiding influence in the erosion
of the broad and deep valley which marks.its course at the surface.

To what extent the dislocations that traverse the Tertiary basalts
of the Inner Hebrides are to be regarded as comparable to those
which in Iceland have been referred to subsidence caused by the
tapping and outflow of the lower still liquid parts of lava-sheets
must be matter for further enquiry. Sofar as my own observations
have yet gone, the faults do not seem explicable by any mere super-
ficial action of the kind supposed. Where they descend through
many hundreds of feet of successive sheets of basalt and dislocate
the Secondary rocks underneath, they must obviously have been
produced by much more general and deep-seated causes.

It is conceivable that, if these dislocations took place during the
volcanic period, they broke up the Java-plains into sections, some
of which sank down s0 as to leave a vertical wall at the surface
on one side of the rent, or even to form open ‘ gijas,’ like those of
Iceland. But it is noteworthy that the fissures which have been
filled with basalt and now appear as dykes, comparatively seldom
show any displacement in the relative levels of their two sides. In
Iceland, also, the great lava-emitting fissures seem to be in general
free from marked displacement of that kind.

The faults in the Inner Hebrides, so far as I have observed, are
all normal, and indicate nothing more than gentle subsidence. But
among the Faroe Islands I have come upon several instances of
reversed faults, which, in spite of the gentle inclinations of the

1 This fault was noticed by Prof. Judd traversing the cliffs of the Sound of
Mull, and is referred to in my memoir already cited.

402 SIR A. GEIKIE ON THE TERTIARY [May 1896, -

basalts, probably point to much more vigorous displacement within
the terrestrial crust.
On the eastern side of Sviné Fig. 31.—Reversed fault on the

a fault with a low hade runs eastern side of Svind, Faroe
from sea-level up to the top of Isles.

the cliff, a height of several

hundred feet. It has a down- a

throw of a few yards, but isa -7> an

reversed fault, as will be seen he

|
from fig. 31. Another similar — | ll}, )} \|HI\M
instance may be noticed on 77 Se
the north-eastern headland of | ‘il | |
Sando, where, however, on the | || IH
upcast side, the basalts appear
as it they had been driven up-
ward, a portion of them having
been pushed up into a low arch
(fig. 32).

When the Tertiary basalt- Fig. 32.—Reversed fault on the
plateaux come to be worked out N.E. headland of Sando, Faroe
in detail, many examples of Tsles.
dislocation will doubtless be
discovered. We shall then
learn more of the amount and
effects of the terrestrial dis-
turbances which have affected
North-western Europe since
older Tertiary time. In the
meantime evidence enough has
been adduced to prepare us for
proofs of very considerable re-
cent displacements even among
regions of crystalline schists
like that which has been disrupted by the Morven fault above
alluded to. While the study of the Tertiary volcanic rocks demon-
strates the vast general denudation of the country since older
Tertiary time, the proofs that these rocks have been faulted acquire
a special interest in relation to the origin and evolution of the
topography of the region.

—— ao

X. Tue Errects or DENUDATION.

Among the more impressive lessons which the basalt-plateaux of
North-western Europe teach the geologist, the enormous erosion of
the surface of this part of the continental area since older Tertiary
time takes a foremost place. He may be ready almost without
question to accept the evidence adduced in favour of a vast amount
of denudation among such soft and incoherent strata as those of
the older Tertiary formations of the South-east of England. But
he is hardly prepared for the proofs which meet him among the
north-western isles that such thick masses of solid volcanic rocks
have been removed during the same geological interval.. -

Vol. 52.] | BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 403

To gain some idea of the amount of this waste we must, in the
first place, picture to our minds the extent of ground over which the
lavas were poured, and the depth to which they were piled upon it.
Whether the now isolated basalt-plateaux of Britain were once
united into a continuous plain of lava may never be ascertainable.
It is quite certain that every one of these plateaux was formerly
much more extensive than it is now, for each of them presents as
its terminal edge a line of wall formed by the truncated ends of
horizontal basalt-sheets. And there seems no improbability in the
assumption that the whole of the great hollow from the centre of
Antrim up to the Minch was flooded with lavas which flowed from
many vents between the hills of ancient crystalline rocks forming
the line of the Outer Hebrides on the west, and those of the
mainland of Scotland on the east.

The depth to which some parts of this long hollow were over-
flowed with lava exceeded 3000 feet. The original inequalities of
surface were buried under the volcanic materials which were spread
out in a vast plain or series of plains, like those that have been
deluged by modern eruptions in Iceland. Owing, however, to a
general but unequal movement of subsidence, the lava-fields sank
down here and there to, perhaps, an extent of several hundred feet,
so that the old land-surface on which they began to be poured out
now lies in those places below the level of the sea.

I have shown that even during the volcanic period, while the
lavas were still flowing from time to time, erosion was in active
progress over the surface of the volcanic plain. The buried river-
channel of the Scuir of Eigg, and the records of water-action described
in the present paper, prove that rivers descending from the moun-
tains of the Western Highlands carried the detritus of these uplands
for many miles across the lava-fields, swept away the loose material
of voleanic cones, and cut channels for themselves out of the black
rugged floor of basalt.

The erosion thus early begun has probably been carried on
continuously ever since. The present streams may be looked upon
as practically the same as those which were flowing in the Tertiary
period. There may have been slight changes of level, oscillations
both upward and downward in the relative positions of land and
sea, and shiftings of the watercourses to one side or other; but
there seems no reason to doubt that the existing basalt-plateaux,
which were built up as terrestrial areas, have remained land-surfaces
with little intermission ever since, although their lower portions may
have been in large measure submerged.

In the existing valleys, fjords, and sea-straits by which these
plateaux have been so deeply and abundantly trenched, we may
recognize some of the drainage-lines traced out by the rivers which
flowed across the volcanic plains. The results achieved by this
prolonged denudation are of the most stupendous kind. ‘The
original lava-floor has been cut down into a fragmentary tableland.
Hundreds of feet of solid rock have been removed from its general
surface. Outliers of it may be seen scattered over the mountains
of Morven, whence they look into the heart of the Highlands.
Others cap the hills of Rum, where they face the open Atlantic.

Q.J.G.8. No. 206. 25

404 SIR A. GEIKIE ON THE TERTIARY [May 1896,

Far away from the main body of the plateau in Skye, a solitary
remnant, perched on the highest summit of Raasay, bears eloquent
witness that the basaltic tableland once stretched far to the east of
its present limits.

Some of the valleys thus excavated out of the volcanic sheets are
many miles long, a mile or more wide, and, from crest to bottom,
several thousand feet deep. The deep winding sea-lochs of Mull and
the west of Skye form striking monuments of this part of the waste.

Yet, impressive as are these proofs of denudation, they are perhaps
inferior in this respect to the evidence furnished in the same region
by the great cores of gabbro and granophyre. These eruptive masses
must once have lain under a thick pile of basalt, for they obviously
belong to part of the deeper-seated mechanism of the volcanic vents.
Yet of this vast overlying mantle every trace has been stripped off
from many of these cores, while in others mere patches of it remain
where they were welded to the intrusive bosses by the heat of
eruption.

Moreover, the cores of gabbro and granophyre have been inter-
sected by abundant dykes which reach the present surface of the
ground, even up to the crests of the mountains. It is certain that
the uprise of these thousands of dykes could not have taken place
except under cover of a great depth of rock now removed, for other-
wise the basalt would have rushed out from the fissures at the foot
of the hills and filled up the valleys, instead of rising between the
fissure-walls to the summits of the ridges. Not a single vestige of
any lava-stream younger than the gabbros and granophyres has yet
been discovered. It is quite possible, perhaps even likely, that the
post-granophyre dykes did lead to the outflow of lava here and
there at the surface. But any proofs of such emission have been
utterly destroyed in the extensive degradation which the plateaux
have undergone. By this process of reasoning we can demonstrate
that valleys in Skye and Mull 3000 feet deep have been excavated
out of the Tertiary volcanic series.

Among the Faroe Islands the evidence of erosion is, in some
respects, even more striking. I shall never forget the first impression
made on my mind when the dense curtain of mist within which I
had approached the southern end of the archipelago rapidly cleared
away, and the sunlit slopes and precipices of Sudero, the two Dimons,
Skuo and Sando, rose out of adeep blue sea. ach island showed its
prolongation of the same long level lines of rock-terrace. The eye
at once seized‘ on these rock-features as the dominant element in
the geology and the topography, for they revealed at a glance the
true structure of the islands, and gave a measure of the amount
and irregularity of the erosion of the original basalt-plateau. And
this first impression of stupendous degradation only deepened as one
advanced farther north into the more mountainous group of islands.
Probably nowhere else in Europe is the potency of denudation as a
factor in the evolution of topographical features so marvellously
and instructively displayed as among the north-eastern members of
the Faroe group. The waste might have been as gigantic among
amorphous rocks, such as granites and gabbros, or even among
schistose masses, like the Lewisian gneiss. But in these materials

Vol. 52.| BASALT-PLATEAUX OF NORTH-WESTERN EUROPE. 405

the eye cannot detect any datum-line by which to estimate the loss.
In the north-eastern part of the Faroe Isles, however, the horizontal
bars of bare rock are continued from cliff to cliff across the deep fjords
into the adjoining islands. These terraces afford not only a demon-
stration that vast hollows have been excavated out of one great
volcanic plateau, but also a measure of at least the minimum
amount of material so removed.

Availing ourselves of these datum-lines, we easily perceive that
in many parts of the Faroe Isles the amount of volcanic material
left behind, stupendous though it be, is less than the amount which
has been removed. ‘Thus the island of Kalso is merely a long
narrow ridge separating two broad valleys which are now occupied
by fjords. The material carved out of these valleys would make
several islands as large as Kalsd. Again, the lofty precipice of
Myling Head, 2260 feet high, built up of bedded basalts from the
summit to below sea-level, faces the north-western Atlantic, and
the sea rapidly deepens in front of it to the surface of the submarine
ridge 200 to 300 feet below. The truncated ends of the vast pile
of basalt-sheets which form that loftiest sea-wall of Europe bear
testimony to the colossal denudation which has swept away all of the
volcanic plateau that once extended farther towards the west.

Nevertheless, enormous as has been the waste of this plateau of
the Faroe Islands, we may still trace some of its terrestrial features
that date back probably to the volcanic period. Even more distinctly
than among the Western Isles of Scotland, we may recognize the
position of the original valleys and trace some of the main drainage-
lines of the area when it formed a wide and continuous tract of land.

A line of watershed can be followed in a south-westerly direction
from the eastern side of Videré, across Boré to the centre of Osterd,
and thence by the Sund across Stromé and Vaagé. From this line
the fjords and valleys diverge towards the north-west and south-east.
There cannot be any doubt that on the whole this line corresponds
with the general trend of the water-parting at the time when the
Tertiary streams were flowing over the still continuous volcanic
plain. Considerable depression of the whole region has since then
sent the sea up the lower and wider valleys, converting them into
fjords, and isolating their intervening ridges into islands.

The topography of the Faroe Islands seems to me eminently
deserving of careful study in the light of its geological origin. There
is assuredly no other region in Europe where the interesting problems
presented by this subject could be studied so easily, where the
geological structure is throughout so simple, where the combined
influences of the atmosphere and of the sea could be so admirably
worked out and distinguished, and where the imagination, kindled
to enthusiasm by the contemplation of noble scenery, could be so
constantly and imperiously controlled by the accurate observation
of ascertainable fact.

Disovssion.
The Presipent, after complimenting the Author on the clearness

of the exposition of his views, said that from his descriptions we not
only obtain a view of these old volcanic vents and lava-flows, but

406 THE TERTIARY BASALT-PLATEAUX OF N.W. EUROPE. [May 1896.

also a graphic picture of the features of the ancient lands now only
represented by these Western Isles. We see, by the traces of old
river-courses, their former connexion with the mainland, and are
able to realize the enormous work which subaerial and marine
denudation have effected over this great area of the north-west.

Prof. Sortas remarked that, in listening to this important con-
tribution, he had been greatly impressed with the uniformity in
character of the rocks belonging to the great Gaelic-Icelandic pro-
vince. The granophyre on the table from St. Kilda was 8o precisely
similar to the granophyre of Mourne and Carlingford that, without
labels, it would be impossible to distinguish the rock in hand-
specimens. It was therefore the less surprising to find that the
same order of extrusion was maintained in places so far apart
as Carlingford and St. Kilda. No deduction in favour of a regular
order of differentiation from basic to acid igneous products could,
however, be drawn from this province; and now less than ever,
since Sir Archibald Geikie had pointed out that granophyres were
among the most recent igneous rocks in Iceland. The speaker
welcomed the confirmation which Mr. Harker had afforded of
observations previously made at Barnavave. The constancy in
direction of dykes over wide areas stood in direct relation to the
constancy in direction of the thrusts which prevailed over Europe-
Asia during the Tertiary period. In Ireland, as Sir A. Geikie had
already shown, the dykes ran from S.E. to N.W., and this direction
closely corresponded to that of normals to the axes of the folds: the
change in direction of the dykes in Iceland was of great interest,
and might furnish evidence of the direction of the concealed folds of
that island, which had in all probability been subject to thrusts —
coming from the south and west.

Mr. W. W. Warts remarked that at the time this paper was being
read Prof. Cole was probably communicating one on the rhyolites of
Antrim at the Royal Dublin Society. Were there no rhyolitic lavas
on the Scottish side of this great province? The reported difference
between pre-granophyre and post-granophyre dykes, if substantiated,
would be of great value in Ireland as well as in Scotland. He did
not quite understand what connexion there was between the old
river of Canna and that of Higg, if one was overflowed by pitch-
stone and the other by plateau-basalt. He referred to the work of
Prof. Iddings on the composite dykes of the Electric Peak.

Dr. Du Ricur PRettEeR wished to ask the Author, with reference
to the third section of the paper, what was the material immediately
underlying the two alternations of conglomerate at the eastern end
of Canna. Assuming the conglomerate to be fluviatile, one would
expect it to rest on sand, which, whether loose or hardened to sand-
stone, should be of a certain depth, the more so as the conglomerate
was in each case as much as 100 feet in thickness.

The AvrHor thanked the Fellows for their cordial reception of
his paper, and briefly replied to the questions that had been put by
the previous speakers.

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PAPERS READ.

7. Messrs. A. J. Jukes-Browne and W. Hill on the Cenomanian of 8.W. England
and. W.,.. WrancempoQleipGn 8 hats cmtn diets aa rete desk. cette Be Mie eab ens era Peeeee - 99

8. Mr. G. W. Lamplugh on the Speeton eres in Yorkshire and Lincolnshire... 179 _

9. Dr. Henry Woodward on Cretaceous Podophthalmata from Vancouyer and
Queen Charlotte Islands ............. si punwiars axe ntaeaen ga sas + 4/t6 leita eee eee 22]

10. Dr. Henry Woodward on Calais Newboldi. (Plate VI.) ....ceccccecessseeees veveee 299

11. Mr. Philip Lake on the British Silurian Species of Aczdaspis. (Plates VII

CCRTUE ee ORS » 935

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13. Dr. Henry Hicks on the Morte Slates, and Associated Beds, in North Devon a
and West Somerset. (Plates X. & XI. )iccescouteerdeesensdteectiestt tt ——— 254

14. Miss G. L, Elles and Miss E. M. R. Wood on the Llandovery and Associated.
Rocks of Conway

senSigdioce ees eectwcteegnagas socks awncscs' agit tiee a ceria aan (2738
15. Prof. T. W. E. David on Glacial Action in Australia in Permo- Carboudeenie
mie. CP labesK TT.) sos. sc..seacsnaenssvecusavtesnpsieasehieth aantannut ate (ean 2
16. The Rey. Edwin Hill on Transported Boulder Clay ............:ssssssserssesseeeree BOD
17. Prof. Edward Hull on the Geology of the Nile Valley ............cccsssccseceeeeees 308
18. Mr. Alfred Harker on the Granophyres of Strath, Skye. (Plates XIII. &.
Uo scatecne ns ocaenehsvadeveeees ves ects sheds «ete tet sat BELG sha se 820
19. Sir Archibald Geikie on the Tertiary Basalt-plateaux of North-western Europe.
(Pinte XV AUX). «0. velcessnccncaescosueds cat ales tele ts at ean neuen ce oe ae 331

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Vol. 52.] THE FAUNA OF THE KEISLEY LIMESTONE. 407

20. The Fauna of the Kotstey Limestone.—Parr I. By F. R.
Cowezr Rezp, Esq., M.A., F.G.S. (Read February 26th, 1896.)

[Prares XX. & XXL]

Dourtne a recent rearrangement of the fossils from this limestone in
the Woodwardian Museum my interest was especially aroused by
the number of peculiar and unnamed specimens amongst them;
and I was thus led to examine them with particular care, and sub-
sequently to visit Keisley myself and collect more in the field, as
well as to inspect Prof. Harkness’s collection at Carlisle, and the
specimens in some small private collections. The following de-
scriptions have therefore been based on the examination of as large
an amount of material as wasavailable. Prof. Harkness’s collection
at Carlisle and that of Prof. Nicholson and Mr. Marr at Cambridge
are those upon which the well-known lists of Keisley Limestone
fossils have been founded; the last list was published by Prof.
Nicholson and Mr. Marr in 1891.3

By carefully removing the matrix I have been able to bring out
many minute characters previously invisible, and have also dis-
covered several entirely new species, which make an important
addition to our knowledge of the bed. :

My thanks are due to Mr. Marr, Prof. Nicholson, Mr. Goodchild,
Chancellor Ferguson, of Carlisle, Mr. E. T. Newton, and others for
help and information.

In this first part of my communication the trilobites alone are
dealt with, being the largest and most characteristic section of the
fauna. In the second and concluding part the rest of the fossils
will be described, and the general relations of the fauna discussed.

CRUSTACKA—Trinosira.
A list of fossils from the Keisley Limestone was published in
1865? by Prof. Harkness. Amongst them he recorded the following
trilobites :—

Cheirurus clavifrons, Dalm. Ilienus Davisi, Salt.
bimucronatus, Murch. Lichas, sp.
octolobatus ?, M‘Coy. Harpes, sp.

Ampyx tumidus ?, Forbes.
Again, in 1877,° Profs. Harkness and Nicholson gave the follow-
ing list :-—

Spherexochus mirus, Beyr. Menus Davisi, Salt.
Cheirurus jguvenis, Salt. Calymene Blumenbachi, Brongn.
bimucronatus, Murch. Agnostus, sp.
gelasinosus, Portl. Ampyx Sarsii, Portl.
cancrurus, Salt. Remopleurides, sp.
octolobatus, M‘Coy. Bronteus, sp.
Liichas laxatus, M‘Coy. Proetus, sp.

Illenus Bowmani, Salt.

* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 507.
? Ibid. vol, xxi. (1865) p. 243.
* Ibid. vol. xxxiii. (1877) p. 468.

Q. J.G. 8. No, 207. 2¥

408

MR. F. R. COWPER REED ON THE

[Aug. 1896,

And in 1891? Prof. Nicholson and Mr. Marr published a new

and revised list of the fossils from this bed.

All the specimens

collected by them at that time are in the Woodwardian Museum.
The following species of trilobites are recorded :—

Ampyx tumidus, Forbes.
Cheirurus bimucronatus, Murch.
cancrurus, Salt.
clavifrons, Dalm. (?).
Cyphaspis (?) ef. triradiatus,
Tornquist.
Cyphoniscus socialis, Salt.
Homalonotus punctillosus,
Tornquist.

Illenus Bowmani, Salt.

cf. conifrons, Billings.

, sp.

Tichas an Wahl.

laxatus, M‘Coy.

Remopleurides cf. longicostatus,
Poril.

Spherexochus calvus, M‘Coy.

The list which I am now able to give as the result of my in-

vestigations is as follows :—

AGNOSTIDE,
Agnostus cf. Galba, Billings.

TRINUCLEIDZ.

Ampyx binodulosus, sp. 0.
Tiresias insculptus, M‘Ooy.

OLENID#.
Remopleurides Colbiz, Portl.
longicostatus, Port).
Cyphoniscus socialis, Salt.

CALYMENIDA.

Calymene Blumenbachi, var. Caractaci,
Salt.

Homatlonotus ? punctillosus, Tornquist.

ILLANIDA.
Illenus Bowmani, Salt.
—— — ., var. brevicapitatus, v. n.
, var. longicapitatus, v. n.
fallax, Holm.
Remeri, Volborth.
cecus, Holm.
galeatus, sp. n.
, 8p., hypostome.

TH

Cheirurus ef. clavifrons, Dalm. ?
(Pseudospherexochus) conformis,
Angelin.

( ) subquadratus, sp. n.
Spherocoryphe granulata, Angelin?
Spherexochus mirus, Beyr.
latirugatus, sp. Nn.

Staurocephalus Murchisoni, Barrande.

ACIDASPID.
Acidaspis convexa, sp. n. |
, Sp. |
LIcHADA.

Lichas laxatus, M‘Coy.

affints, Angelin.

conformis, Angelin, var. keisley-
ensis.

hibernicus, Port.
— bulbiceps, Phillips, MS. |
—— bifurcatus, sp. n.

PROETIDA.
Cyphaspis ? Harknessi, sp. n.
( Tornquistia, subgen. nov.)
Nicholsoni, sp. n.
Phillipsinella parabola, Barrande.

CHEIRURIDZ. Tae ne
a Cerne Murchison, Harpes Wegelini, Angelin.
Bae crurus, Salt. costatus, Angelin ? |
—— keisleyensis, sp. 0. 2 - : B. -
ef. glaber, Angelin. ee ie ,
AGNOSTID #.

Aenostus cf. GaxBa, Billings.

A pygidium of this species in a remarkably good state of pre-
servation was found by me during a recent visit to Keisley. It

* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 507.

Vole 5a] FAUNA OF THE KEISLEY LIMESTONE. 409

possesses all the characters of Billings’s species’ which occurs in the
Quebec group, except that the axis in our specimen is rather shorter
than in his figure, and therein approaches Agn. tardus of Barrande.”
The ornamentation of the surface, of which Billings says (loc. cit.)
that one specimen showed indications, is very clearly exhibited, and
consists of fine reticulating or undulating raised lines or fine
wrinklings on the zone of the lateral lobes; the stri# run more or
less concentrically to the margin of the pygidium. The remainder
of the test is smooth.

The specific differences of this species from Agn. tardus (see
Billings, loc. cit.) are :—(1) The elongated central tubercle on the
axis is elevated at its abrupt posterior extremity to twice its height
at its anterior end.

(2) The zone of the lateral lobes is ornamented by fine wrinklings

or raised lines.
TRINUCLEID&.

AMPYX BINODULOSUS, sp. n. (PI. XXI. fig. 1.)

The specimen in the Woodwardian Museum which had been
assigned to Forbes’s species .4. twmidus cannot, in my opinion, be
allowed to remain in that species for the following reasons :—
(1) The cheeks unite with the glabella in front of the middle of its
length; (2) at the base of the glabella are two distinct circular
nodules or lobes, which occupy nearly its whole breadth so as
almost to touch each other in the centre.

There is another smaller specimen of this new species in the
Harkness collection at Carlisle.

The glabella is almost lanceolate in shape, but is truncated
abruptly behind by the distinct neck-furrow. In front the glabella
tapers gradually into a grooved spine (broken off short in our
specimen),

The glabella is most convex from side to side at the level where it
becomes free and projects in front of the cheeks ; from its posterior
end to the base of the spine it is very gently and regularly convex.
A faint keel runs longitudinally down its centre, and at the base
of the glabella he the pair of circular flattened lobes or areas, one
on each side of the keel. These circular areas or lobes scarcely
rise above the general level of the glabella at this part, but extend
nearly across its whole breadth, giving it a very characteristic
appearance.

The cheeks are triangular, somewhat swollen and distinctly
marked off by shallow axal furrows from the glabella, with which
they unite at a point rather in front of the middle of its length.
Near the anterior end of each axal furrow and in its course there
lies a small but deep pit. The genal angles appear to have been
produced into rounded spines.

The neck-segment is narrow, but distinctly marked off from the

' Billings, Geol. Sury. Canada, Palxozoic Fossils, vol. i. (1865) p. 297, fig. 288.
Barrande, ‘ Syst. Sil. Bohéme,’ yol. i. (1852) p. 918, pl. xlix.
2¥F2

410 MR, F. R. COWPER REED ON THE [Aug. 1896

cheeks and glabella by a neck-furrow. The posterior border of the
head-shield is not straight, but formed of three gentle backward
curves—the lateral ones bounding the neck-segment behind the
cheeks and the middle one the neck-lobe of the glabella.

The whole surface of the cheeks and glabella is finely punctated,

Affinities. —The two points of difference already given distinguish
this species from A. twmidus, to which it seems otherwise allied.
A,..(Raphiophorus) depressus of Angelin is distinguished by the
smaller size of the circular basal lobes, their greater distance apart,
the shortness of the glabella, and its practical non-carination.

TIRESIAS INscuLPTUs, M‘Coy.

This peculiar trilobite is apparently allied to Ampya, as M‘Coy
says. It is very rare in the Kildare Limestone, and I have only
seen one specimen from the Keisley Limestone, and that is in the
Carlisle Museum. |

In M‘Coy’s figure! there are two small indentations near the
base of the glabella, but they are not mentioned in his description,
nor are they seen in the Keisley specimen. The last-named shows
that the cheeks are prolonged as a narrow flattened band in front
of the glabella, but there is no true border to the head-shield.
The axal furrows are also wider than M‘Coy figures. The wavy
thread-like lines which ornament the glabella are roughly con-
centric to its front end, and those on the triangular convex cheek
are roughly parallel to the lateral edge of the head-shield. The
other features are given in M‘Coy’s description, and need not be
repeated.

Length of head-shield 9°5 millim.; width (estimated) of the
same at the base 14:0 millim.

OLENID &.
RemoPirvuripes Corsit, Portl.

There are two beautifully-preserved thoracic rings and pleure in
the Woodwardian Museum, showing the characteristic ornamenta-
tion of the species with great distinctness, but no other portion of
this trilobite is known.

REMOPLEURIDES Lonercostatus, Portl.

In the collection made by Messrs. Marr and Nicholson from the
Keisley Limestone there is an exceedingly fine head (minus the free
cheeks) of this species, showing the ornamentation most distinctly.
Salter’s description (Mem. Geol. Surv. dec. viii. text with pl. vii.
p. 9) makes any further remarks on my part superfluous. The
species also occurs in Prof. Harkness’s collection at Carlisle.

CypHoniscus socraLis, Salter.

The head-shields of this peculiar little trilobite are not very
common at Keisley. Nevertheless 1 have found several there

1 M‘Coy, ‘Syn. Silur. Foss. Irel.’ pl. iv. fig. 1, p. 43.

Vols 52: FAUNA OF THE KEISLEY LIMESTONE. 4\1

recently, but have no further particulars to add to Salter’s minute
description of its characters.

Only one pygidium, 4 millim. in length, has so far been dis-
covered at Keisley, and this must have belonged to a large
individual.

CALYMENID.

CatyMENE BLruMENBACHI, var. Caracract, Salter.

The genus Calymene has been recorded from the Keisley Lime-
stone by Prof. Harkness. A glabella and pygidium belonging to
the above species have recently been tound in the state of internal
casts, but exhibiting all the usual well-known characters.

Homatonorvus ? puncritxosus, Tornquist.

Prof. Nicholson and Mr. Marr were the first to record this
curious trilobite from the Keisley Limestone, and in fact from
England.* But it had been collected many years previously from
that bed by Prof. Harkness, for I found unnamed specimens of it
in his collection at Carlisle. It had also been long ago found at
the Chair of Kildare, but was named Asaphus? and Olenus? It
is still open to doubt whether it is correctly placed in the genus
Homalonotus, and it appears closely allied with Billings’s genera
Bathyurus and Buthyurellus, to one of which it may subsequently
have to be referred. Tornquist describes and figures it in the
Swedish Geological Survey Memoirs” from the Leptcena-Limestone.

ILL2NID 2,
Ittznus Bowmant, Salter.

The determination of the species or varieties of the genus Jllenus
has been a matter of considerable difficulty, inasmuch as the common
I, Bowman varies considerably in outline and convexity of the
head-shield. Some specimens also show an ornamented surface,
whereas Salter described the surface as smooth. After carefully
examining a very large series of specimens I believe that I can
establish two fairly well-marked varieties of the typical form, and
these I have respectively called J. Bowmant, var. longicapitatus, and
I. Bowmani, var. brevicapitatus. The typical form of £. Bowmani
also occurs, and there are found some individuals which can with
difficulty be assigned to any of the three, for they possess inter-
mediate characters.

Thus one specimen of a head-shield has all the characters and
the ordinary shape of the typical Z. Bowmani, but its surface is
ornamented with raised lines as in the variety brevicapitatus.

Again there are some head-shields of a pointed form like the
variety longicapitatus, but without the conspicuously sudden down-
ward curvature of the front end of the head-shield.

‘ Marr & Nicholson, ‘The Cross Fell Inlier,’ Quart. Journ. Geol. Soc.
vol. xlvii. (1891) p. 507.

* S. L. ‘Tornquist, ‘ Undersékn. éfv. Siljansomradets Trilobitfauna,’ Sver.
geol. Undersokn. 1354, p. 44, pl. i. figs. 46 & 47, pl. ii. figs. 1 & 2.

412 MR. F. R. COWPER REED ON THE [Aug. 1896,

Again others have the abrupt posterior truncation as in J. Davist,
but all the other characters of 7. Bowman.

The amount of curvature and convexity of the head-shield is a
variable feature, and not of much classificatory importance.

Irtanus Bowmant, var. tonetcaprtatus. (Pl. XX. fig. 5.)

Head-shield parabolic to semi-oval, the hinder two-thirds of the
surface flattened, but the front curves down suddenly and steeply.
Neck-furrow plainly visible on the cheeks. Surface of the head-
shield minutely punctated. ye rather more forward than in the
type-form. Other characters identical.

The measurements of one specimen are given to show the pro-
portionate size of the different parts of the middle shield.

millim.
MAME AOr SNC... yoae snes doseage send lvasscclnen ne see oeeene 33°0
WWaclemvotrdosatilevel of @yes | a-c.cesc: weacesdans iwsse sae 41:0
ene trols ela bellan. wives secre sceannesesciedsn ese seme eae 15°5
NWhidthWor dor at base... £2. cissb- se sbloasideacek eecenee. See 18:0
Width otdixed: cheek at eyes j..0-h.accdeeroeperse <oeeoee 12-0

Note.—Some of the head-shields of J. angustefrons, Holm, re-
semble in general appearance those of this variety, but the eyes
seem to be larger and more forward in position.

Ittanvus Bowmant, var. BREVIcAPITATUS. (Pl. XX. fig. 4.)

Head-shield transversely elliptical ; length is to breadth as 2: 3.
The anterior edge forms a much flattened forward curve. Glabella
rather shorter than the type-form. Sculpture of middle shield as
follows:—Close to anterior margin and parallel to it are a few
continuous raised thread-like lines, conveniently called ‘ terraced
lines’ by Holm, and between these and the anterior end of the
glabella are present in some specimens shorter scattered similar
lines, arranged more or less concentrically with the margin. On
the glabella itself there are three groups of similar lines, a median
group of short lines arched forward, and a pair of lateral groups of
slightly curved oblique lines. Across the base of the glabella are a
few longer horizontal straight lines. Very minute scattered puncta
occur over the whole surface of the head-shield.

In all points except the above this variety agrees with the type-
form.

Measurements of two Specimens.
pp

IT 101.
millim. millim,
Nieneth of head-shield s..eeeeassstoss secs -2e-<~- 26:0 19°5
Width of do. at level of eyes.....,..-..----+--»+- 34:0 24:0
Distance between facial sutures where they
Chisthe front Tar ein 25) Ae meeewhseae wen Sanas2. 29:0 22:0

Went of elabelllan ai cs ee ete sey. cee sieoiere nes 10:0 79
RVicltiof do, at bases wntenecsenagteeneorocact 17:0 10°5

Vol! sox} FAUNA OF THE KEISLEY LIMESTONE. 413

It,zyus FALLAX, Holm.

There is one specimen of a small pygidium in the Woodwardian
Museum which shows all the well-marked features of Holm’s
I. fallax’ from the Leptena-Limestone of Dalecarlia.

In the shape of the pygidium, the position of the fulcrum, and
the relative size and triangular outline of the axis, with the faint
ridge from its apex to the posterior border, it entirely agrees with
the Swedish specimens.

millim
Beneth OF py Sidi (siscsescccantsascs.cecsesesdveresciseceesd 6°0
PRISON INORG aie ti Se cdstdaveacetadainc «ce tavcaveeyeoaseranaetlse’ 8:5
Hirose palit he cele eam ere 2S ecteses N's sev alc ndsidcuhtene mn ates’ 2°5
NWAOOI OM AOG desc shcocedrtvadssdoaccesesconcakbactedaqsecsb ses 2°5

A specimen of the hypostome of an Jllenus in the Carlisle
Museum closely agrees with that of this species figured by Holm
(op. cit. pl. vi. fig. 116). It is subquadrate in form with a swollen
central portion, and is truncated in front and obtusely pointed
behind. A border of regular width (except at the anterior lateral
angles, where it expands considerably, but is imperfectly preserved)
surrounds it.

The posterior end of the swollen central portion is furnished with
a marginal band, as Holm shows. A few large granules also
ornament the surface of this central portion.

Length=5°5 milim.; width=5:0 millim.

Ittanvus Ramert, Volb.

Both the middle shield and the free cheek of this species are now
known from Keisley, but they had not previously been identified.
However, a comparison of our specimens with the figures and
descriptions of J. Remert (with which Holm’ identifies the Swedish
species I. vivaw* from the Leptena-Limestone) shows that the
identification is correct. The shape of the head-shield, the relative
size of the glabella, the course of the facial sutures, the position
and size of the eyes, the characters of the free cheek, and the
ornamentation exactly correspond. Two imperfect specimens of
hypostomes from Keisley also bear a very close resemblance to the
hypostome of this species as figured by Holm (loc. cit.). In Russia
I. Remer? occurs in the Lyckholm zone.

I~tL=Nvus cacus, Holm.

A solitary broken specimen of a middle shield agrees so exactly
in all points with Holm’s species J. cwcus* from the Lyckholm
zone of the Island of Dagé that I do not feel any hesitation in

1 Holm, ‘Svenska Arterna af Trilobitslagtet Z//enus,’ Bib. k. sv. Vet.-Akad.
Handl. vol. vii. (1882) no. 3, p. 82, pl. ii. figs. 15-20.

* Holm, ‘ Ostbalt. Illxn.’ Mém. Acad. Imp. Sci. St, Pétersbourg, vol. xxxiii
(1886) no. &, p. 125, pl. ix. figs. 4-14.

3 ‘Svenska Arterna Ji/en.’ p. 74, pl. vi. figs. 1-7.

4 «Ostbalt. Illen.’ p. 162, pl. xi. fig. 11 a-d.

414 MR. F. R. COWPER REED ON THE [Aug. 1896,

identifying the two. A badly preserved pygidium of an Jllcenus
from Keisley also shows the characters of that part as described
and figured by Holm.

Measurements.
millim
Length ofmuddilersateldl te incense daciintirlcteontedsasvne 17-0
Wradithi(@reatest mon doe ity penis ceca eeanseseteeticeaes- 30°5
Lengtheot ela pela ers ster atasocnned: «te scere nomen eas rei ae ce 7:0
Widitnvon baserOlsd os osee ese cet aac soon he wcetee hoon 8-0
emetn Ofipye iG nie Giese cecat face vehtos donden cedeet seconde 15:0
WY el Glacairal ahaa ae ik soto clr crs a ooealasn Su abet cera meee ae 29-0
WidthsonairontremadsOnaxiss. <6 5.é<cccaxasaccenns cusp oueaee me)

ILLZNUS GALEATUS, sp.n. (PI. XX. figs. 1, 2 & 3.)

A dozen or more specimens of an Janus in the Woodwardian
Museum, which have their head-shields inflated to an extraordinary
extent, possess a curious combination of characters. There is a great
conical elevation situated nearly in the centre of the middle shield,
and from its summit the surface slopes down regularly to the margins,
but more steeply to the back and front than to the sides. Billings’s
species J. conifrons from the Chazy Limestone of Canada * resembles
these Keisley forms in the abnormal amount of inflation, and
Prof. Nicholson, who presented us with some of our specimens
from Keisley, was accordingly led to compare them.’ But in reality
these British individuals are widely separated from the Canadian
species by several essential structural features. which are pointed
out below.

The description of the Keisley form is as follows :—

The middle shield is nearly semicircular in front; its posterior
margin is almost straight; the width is about half as much again
as the length. It slopes up regularly from all sides to a subcentral
conical elevation, the summit of which is obtusely rounded and
situated immediately in front of the glabella. The profile of the
middle shield across its middle, seen from behind, is like the small
end of a fowl’s egg ; but viewed from the side the profile is semi-
elliptical. The posterior slope is a little steeper than the anterior,
and these two slopes are more convex than the lateral slopes, the
latter being decidedly flattened. The vertical height of the middle
shield is about half its greatest width.

The glabella is short, occupying only about two-thirds of the
length of the posterior slope. It is about one and a quarter times
as long as wide. It is almost rectangular and parallel-sided in
shape; but it suffers a very little contraction in the middle through
the gentle inward curvature of the axal furrows. It is undefined
in front, but is bounded posteriorly by a shallow, though distinct
neck-furrow which is arched slightly forward and marks off a
narrow occipital ring. The glabella has a convexity independent

1 Billings, ‘ Canadian Naturalist and Geologist,’ vol. iv. (1859) p. 378; and
Rep. Progr. Geol. Surv. Canada, 1868, ch, ix. p. 151, fig. 111, a, 0.

2 Marr and Nicholson, ‘The Cross Fell Inlier, Quart. Journ. Geol. Soc.
vol. xlvii. (1891) p. 507.

Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 415

of that of the general surface of the middle shield and of that of
the fixed cheeks above which it rises. The convexity of the glabella
is continued in front of the free termination of the axal furrows up
to the summit of the middle shield, where it is lost.

The axal furrows are distinct, of moderate depth and breadth,
have a curved course, and bend slightly outward at both their ends,
though more strongly posteriorly. They extend up about two-
thirds of the posterior slope of the middle shiel..

Each of the fixed cheeks is at its base nearly as wide as the
glabella, and, owing to outward curvature of the facial suture from
the posterior margin, it rapidly increases in width forward as far
as a point a little in front of the anterior end of the axal furrows.
Here it has a width twice that of the glabella. The fixed cheeks
fall down steeply and abruptly at their base to the narrow neck-
segment.

There is no trace of an eye-lobe, and the species must have been
blind.

The facial sutures cut the front margin at a distance from each
other of about twice the width of the glabella. Each suture curves
strongly outward and backward to the level of the front end of
the glabella, behind which level it runs backward and inward, at
first in a convex outward course and then with a slight inward
curve, so as to cut the posterior margin at a distance from the axal
furrow nearly equal to the width of the glabella.

The front margin of the middle shield is furnished with a distinct
marginal furrow which marks off a narrow, raised, rounded border.

The free cheeks are not preserved ; but, judging from the curvature
of the front margin, the course cf the facial suture, and their shape
in allied forms, they must bave been long and narrow.

The whole surface of the middle shield is ornamented with very
closely-set puncta.

Measurements of two Specimens.

if i
millim. millim,
Heneth afmiddle shields... as. cseseccescssanes 24:0 18-0
ESSE AL AGI OL COs jaccecvecndssaceusased desener’ 35°5 25:0
Snes bent Meth OF CO.i cuisines ile son ox caersrinso oes 15:0 9-0
Length of glabella (to end of axal furrows)... 13:0 70
VRINENON CO, At) DASE) .2csc. clo cevc.sccccecescecane 11:0 8:0
Greatest width of fixed cheek .................. 19°5 12:0

(At a level a little in front of the anterior end of the glabella.)

Note.—There are several smaller specimens not quite so much
elevated in the centre of the middle shield as those above described.
But in all other respects they agree with them completely, and
must be considered, at any rate for the present, merely as young
individuals or a variety of the same species.

Illenus galeatus is a very common form at Keisley. There are
specimens of it in Prof. Harkness’s collection at Carlisle, but it is
labelled Jil, Davisi. There are numerous excellently preserevd

416 MR. F. R, COWPER REED ON THE [Aug. 1896,

head-shields in the Woodwardian Museum, Cambridge, collected by
Messrs. Marr and Nicholson and by myself.

Affinities.—From JI. conifrons, Billings, our species is distin-
guished by the absence of eyes, the shortness of the axal furrows,
the non-gibbosity and shortness of the glabella, etc. The amount of
inflation of the head in the two forms is very similar and gives them
a spurious look of affinity. Our Keisley form belongs, however, to
that group of blind Z//a@ni which have been described from Bohemia,
Russia, and Sweden; J. Angelini (Holm) * and J. leptopleura (Linrs.)
are the two blind species known from Sweden. With the former
our British species agrees in the relative length and width of the
glabella and the fixed cheeks, in the course of the axal furrows and
of the facial suture, and in the absence of eyes; but differs in the
amount of inflation and length of the head-shield. J. cwcus (Holm)?
from the ‘ Lyckholmer Schicht F’* of the Baltic area comes very
close to our species except in the amount of inflation, breadth, and
curvature of the head-shield. The three Bohemian species, J. Katz-
eri (Barr.), I. Zeidleri (Barr.), and J. aratus (Barr.), bear comparison;
and all the seven appear to be closely allied by structural peculiarities.
But the absence of eyes, which leads to a modification in the course
of the facial suture and shape of the free cheeks, is said not to
be accompanied by any changes in other parts of the body; and
Barrande and Holm do not consider that there is sufficient justi-
fication for the creation of a new genus, particularly as a similar
disappearance of the eyes and modification of the facial sutures and —
free cheeks is found in the genus Conocephalites.

Inranvs, sp. (Pl. XX: fig. 6.)

One epistome of an Jllcenus in the Woodwardian Museum
resembles somewhat closely that of J. Davist (Salter), but it is
longer and more pointed posteriorly. In shape this Keisley epistome
is broadly triangular; its anterior side is gently arched forward, and
its posterior sides converge backward with a slight concave-outward
curve to meet at the rounded obtuse apex at an angle of about 135°.

All the three sides are slightly bevelled, but otherwise the
epistome has a flat surface. Nine or ten strongly-marked furrows,
with raised ridges between them, run across the surface from side to
side. Those nearest the front border run across continuously almost
in a straight line from one lateral angle to the other; the more
posterior furrows bend backward in the middle with an increasingly
sharp and strong curvature as they are followed backward. Between
these strongly-bent posterior furrows and those in front are a few
short furrows and ridges in the middle of the epistome. The
anterior edge of the epistome is furnished with a broad smooth

1 Holm, ‘Svenska Arterna af Trilobitslagtet Z//enus,’ Bih. k. sv. Vet.-Akad.
Handl. vol. vii. (1882) no. 3, p. 120, pl. iv. fig. 29.

2 Holm, ‘ Ostbalt. Illen.’ Mém. Acad. Imp. Sci. St. Pétersbourg, ser. vii.
vol. xxxili. (1886) no. 8, p. 162, pl. xi. fig. 11 a-d.

3 Barrande, ‘ Syst. Sil. Bohéme,’ pt. i. suppl.

Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 417.

border. The length of this epistome is 9°5 millim., and its width
from side to side is 33 millim.

CHEIRURID&.
CHEIRURUS BIMUcRONATUS, Murch., var. a, Salter.

It seems that this species, though occurring in the Keisley
Limestone, is not so plentiful as Ch. keisleyensis. ‘There is only a
single pygidium belonging to it in the Woodwardian Museum, and
no undoubted head-shields. Our specimen belongs to the variety a
of Salter,’ in which the terminal mucro between the third pair of
spines is absent.

CHEIRURUS CANCRURUS, Salter.

Two pygidia of this species are in the Woodwardian Museum,
but call for no special notice. Fragments of others are at Carlisle.

Note.—A portion of a glabella agrees fairly well with that assigned
provisionally by Salter to this species.” The elongated shape of the
glabella, the great length of the frontal lobe, and the finely granu-
lated surface are the most striking points of similarity, but the side-
furrows in our Keisley specimen are much longer than those
described and figured by Salter, for each furrow of the front pair
extends across the glabella at least a third of its breadth. The
figure given by Tornquist ° of Ch. znsignis (Beyr.) much resembles
our specimen. The glabella is much more inflated and convex than
that of Ch. bimucronatus or that of Ch. keisleyensis. Ch. conformis
of Angelin* may also be compared with it.

CHEIRURUS KEISLEYENSIS, sp. n. (Pl. XX. figs. 7, 8 & 9.)

This new species is founded on two incomplete pygidia, but some
associated head-shields with less peculiar characters most probably
belong to it. It seems that some of the head-shields have previously
been assigned to Ch. bimucronatus, which they much resemble. But
the features presented by the pygidium are very marked, and distinct
from any British species previously described.

The pygidium is about 12 millim. long, and is furnished with
three distinct pairs of pleuree with free ends. The fourth pair of
pleure and axal segments are represented by a single median, sub-
terminal, triangular piece, embraced laterally and posteriorly by the
third pair of pleure.

The first pair of pleure is the largest of the three pairs, both in
breadth and length. ach pleura of this pair is composed of an
inner attached and an outer free portion. This outer free portion
consists of a long spine. The inner portion is at right angles to

1 Salter, Pal. Soc. ‘Mon. Brit. Trilobites,’ p. 63, pl. vi. figs. 15, 16, & 17.

2 Ibid. p. 73, pl. v. fig. 16.

* Tornquist, ‘Undersokn. ofv. Siljans. Trilobitf.’ Sver. geol. Undersékn.
1884, p. 12, pl. i. fig. 9.

* Angelin, ‘Palxont. Scand’ 1854, p. 32, pl. xxi. fig. 3; Lindstrom,
‘Forteckn. pa Gotl. Silur. Crustac.’ Ofv. k. sy. Vet.-Akad, Férhandl. 1885,
no. 6, p. 45, pl. xiii, figs. 13 & 14.

418 MR. F. R. COWPER REED ON THE [ Aug. 1896,

the axis of the pygidium and extends to a prominent, triangular,
articulating process which ends the narrow articulating band on the
straight anterior edge of this portion. Beyond this articulating
process the pleura becomes free and bends back at an angle of 70°
to the anterior edge of the inner portion. This free or outer
portion of the pleura is produced into a long flattened spine, part of
which is broken off in our specimens. A strong oblique furrow
traverses the inner portion of this pleura and is accompanied by a
ridging-up of the surface on each side of it. Just before the pleura
becomes free it attains its greatest width, which is equal to half the
entire length of the pygidium itself. The outer or free portion
tapers gradually backward and diverges from the second pleura at
an angle of about 50°. The point at which this divergence com-
mences is situated at the level of the anterior edge of the single,
median, subterminal piece of the pygidium.

The pleuree of the second segment are directed backward, and
their free portions consist of spines running back parallel to the
axis, The inner portion of each of these pleure has an anterior
border slightly curved forwards and outwards, but the anterior, or
rather outer, edge of the free portion is almost straight. The
greatest width of this pleura is across the base of the free portion,
as in the first pleura, but it does not amount to more than two-thirds
of the greatest width of the first pleura. The spine of the second
pleura, in addition to being more rounded and slender, cannot have
been more than half as long as that of the first pleura. Neither
the inner nor outer portion of the second pleura bears any furrow
on its surface.

Each pleura of the third pair has its proximal or anterior portion
only about one-third of the greatest width of the second pleura,
with which it is in contact for the whole length of its proximal
portion. These proximal portions of the third pair of pleure are
directed backward and sligbtly inward, but nearly parallel to the
axis of the pygidium and to each other. The flattened distal
portions are notin contact with the second pleure, but bend sharply
inward in close contact with the median posterior piece of the
pygidium, and become nearly double the width of the proximal
portions, to end each in a blunt point.

The median terminal, or rather subterminal, piece of the pygidium
is triangular in shape and is completely embraced laterally and
posteriorly by the third pair of pleure, so that the posterior end of
the pygidium has a bifurcate appearance owing to the bluntly-
pointed extremities of this pair of pleure. There is no furrow on
the last pair of pleure or on the median subterminal piece.

The axis of the pygidium is triangular in shape, it tapers
rather rapidly posteriorly, and its sides meet at the apex of the
median subterminal piece at an angle of about 60°. The axis is very
slightly convex and not much raised above the pleural portions of
the pygidium, It is furnished with three rings, of which the first
is rather broader than the posterior two, which are of equal breadth.
Each ring is rounded and, owing to the extreme weakness and

Fok. an] FAUNA OF THE KEISLEY LIMESTONE. 419

shallowness of the axal furrows, appears to pass laterally into the
pleure without any interruption. The furrows, however, separating
the axal rings are well marked, but weaker in the middle than at
the sides.

The median terminal piece has been described above.

The whole surface of the pygidium is ornamented with minute
granulations.

Affinities.—The general appearance of the pygidium, particularly
with regard to the characters and direction of the first and second
pairs of pleurze, reminds us considerably of Ch. subulatus (Linnars-
son), which occurs in the Z7’rinucleus-schists of Western Gotland ; but
the bifurcated posterior extremity, owing to the projecting ends of
the third pair of pleure, and the triangular instead of quadrate form
of the median piece representing the fourth segment, are conspicuous
differences. The point also at which the first and second pleure
diverge from each other and become free spines is nearly equidistant
from the anterior and posterior ends of the pygidium in our Keisley
form, whereas in the Swedish species this point is on a level with
the posterior end of the pygidium according to Linnarsson’s figure.
The pleure of the third segment in our form are also distinctly
marked off from the axal portion by a transverse groove, whereas
in Ch. subulatus there is no such separation.

The head-shields which I would tentatively ascribe to this species
have been mostly assigned to Ch. bimucronatus, but they do not
strictly agree with the typical form of that species nor with any of
the hitherto recognized varieties. The resemblance between the
pygidium of Ch. keisleyensis and Ch. subulutus has been noticed
above, and when we compare the head-shield of Linnarsson’s species
with these of the so-called Ch. bimucronatus we cannot fail to
remark the close similarity. The chief differences between the
Swedish and Keisley forms are that in the latter the glabella is
broader in proportion to its length, is more parallel-sided, and the
eye is situated in a more forward position on the cheek.

From Ch. bimucronatus the Keisley form differs in the glabella
being of a squarer shape and of greater width at the base, in
the lateral furrows being straighter and not directed so much back-
ward, and in the eye being placed a little in front.of the second
lateral furrow instead of slightly behind it.

Several hypostomes of a large Cheirurus have been found
associated with the above-described species, though not in actual
connexion or attachment. In point of size these hypostomes
would just suit the head-shields of Ch. keisleyensis: they resemble
very closely the hypostome of Ch. bimucronatus figured by Salter.
The central convex portion has its sides a trifle more parallel, and
the posterior end is rather broader and more obtuse, otherwise
there is no apparent difference between the two.

Several disconnected thoracic segments belonging to large
individuals of Cheirurus have been found. It is probable that they

? Linnarsson, ‘Om Veetergotl. Cambr. och Silur. Aflagringar,’ K. sv. Vet.-
Akad. Handl. vol. viii. (1869) no. 2, pl. i. fig. 5, p. 60.

420 MR. F. R. COWPER REED ON THE [Aug. 1896,

belong to Ch. kesleyensis, which is the common species, while
Ch. bimucronatus is very rare. Their characters appear to exactly
correspond with those of the latter species.

CuHErRvrvs cf. GLABER, Angelin.

The single specimen in the Woodwardian Museum on which [I rely
for this determination bears an exceedingly close resemblance to
Angelin’s figure of Cheirurus glaber, Ang., and I do not think it
justifiable to separate it without at any rate seeing Angelin’s
figured specimen. Schmidt’ also describes and figures a species of
Cheirurus which he compares with this species of Angelin’s.

There are no important points of difference between our Keisley
specimen and Angelin’s species, as represented in his figure. The
Russian individuals do not appear to resemble Angelin’s species
so closely. But in the presence of the pair of pits on the frontal
lobe we see a point of similarity between the Russian and English
individuals.

Measurements.
millim

Genet ol head-shield. \ e-qcse-rececmaaresdescnacr aes aaceheee at asec eee 23°0
Be wlabellar. £25 aia comms deeeeeeies sect sans sesiccneee se kere 165
Wadth of do.cat hase... 2.2 :ci scone eeseetee co nese waatiee eee reece aaeenae 13-0
A NG... 4)- across frontal lobesteespers- aa. .cs.2 cece eee 16°5
enethivot frontal lobe: 2-feacenedcsreeeaciaecnn ses alee ariel ase hee 8:5
Width of cheek (along posterior edge) ..............-.2+eeeeeeeneees 13:0
Distance of eye from/axal furrow Weare ce-....255..-.caeaeeoeeme 4:0
ah > pe BPOstetiomedeerorchicek.....:0....-seneaseeeeee 6:0

CHErRURUS cf. cLAvIFRONS, Dalm. ?

Portions of the glabella of a species of Cheirwrus show a resem-
blance to Ch. clavifrons, but the fragmentary nature of our
specimens renders any precise determination impossible.

Currrurus (PseuD0sPH ZREXOCHUS) CONFoRMIS, Angelin.

Messrs. Marr and Nicholson*® in 1888 recorded one species of
this subgenus from the Stockdale Shales and named it Ps. morordes.
Otherwise it has not previously been noticed in Britain. The
species Ch. (Ps.) conformis is a characteristic form of the Leptena-
Limestone of Dalecarlia,* and its occurrence at Keisley is another
important link in the chain of evidence connecting these two
limestone patches.

Angelin® figures and describes the species, but imperfectly ; now-
ever, Schmidt ° gives a full description and excellent illustrations in

1 Angelin, ‘ Palzont. Scandin.’ 1854, pl. xxxix. fig. 16, p. 79.

2 Fr. Schmidt, ‘ Rev. d. ostbalt. Silur. Trilob.’ pt.i. p.151, pl. vii. fig. 18 @ & 3,
Mém. Acad. Imp. Sci. St. Pétersbourg, ser. 7, vol. xxx. (1881) no. 1.

3 Quart. Journ. Geol. Soe. vol. xliv. (1888) p. 722, pl. xvi. figs. 9, 10 & 10a.

4 Tornquist, ‘Undersodkn. ofv. Siljansomradets ‘Trilobitfauna,’ Sver. geol.
Undersokn. 1884, p. 18, pl. i. fig. 12.

5 Angelin, ‘ Paleont. Scandin.’ 1854, p. 76, pl. xxxix. figs. 2, 2a.

6 Schmidt, ‘ Rev. d. ostbalt. Silur. Trilob.’ pt. 1. p. 174, pl. x. figs. 5, 6 7, 9,
& pl. xvi. figs. 28-30, Mém. Acad. Imp. Sci. St. Pétersb. ser. 7, vol. xxx. (1881)
m0. A.

Vol. 52. ] FAUNA OF THE KEISLEY LIMESTONE. 421

his work on the East Baltic trilobites. Some of our specimens do not
correspond with the type-form of the species, but more closely with
the variety which Schmidt describes (op. cit. p. 176); and the very
close relationship of the two species Ps. hemicranium (Kut.) and
Ps. conformis (Ang.) var. of Schmidt is brought out by a minute
comparison of them. Schmidt himself says that these two species of
Pseudospherexochus stand very close to each other, and the feature
of the greater length of the glabella is almost lost in the variety
from Borkholm.

In addition to several head-shields, a typical pygidium has been
found at Keisley which measures nearly 2 millim. in length (ex-
cluding the spines), and 3°5 millim. in breadth.

It was from a pygidium similar in all respects to this one that
Harkness recorded Ch. octolobatus from the Keisley Limestone.

CHErRURUS (PsEUDOsPH HREXOCHUS) SUBQUADRATUS, sp.n. (PI. XX.
figs. 10 & 11.)

In addition to Ch. (Ps.) conformis (Ang.) in the Keisley Limestone,
there occurs in greater abundance a form which must be considered
very closely allied to Kutorga’s species Ch. (Ps.) hemicranium, which
has been described by various authors, and recently with minuteness
by Schmidt.'| The characters of the Keisley form are well marked
and constant, but unfortunately only the head-shields are known. I
hesitated for some time whether it could be satisfactorily separated
from Ch. (Ps.) hemicranium, but with the advantage of more
material for examination I am convinced that the new species rests
on quite as firm a foundation as Oh. (Ps.) conformis (Ang.).

The description is as follows :—

The head-shield is almost semicircular in form, but the length is
a little more than half the breadth. The glabella occupies more
than one-third of its breadth and is rounded-subquadrate in shape ; it
is strongly convex and much elevated above the downwardly-sloping
cheeks. The highest point of the glabella is situated about halfway
along its length. ‘The anterior part in front of the basal lobes is
bent downward and more rounded and convex than the posterior
part, which is slightly flattened. The length of the glabella is equal
to the width, and the quadrate appearance is due to the width at
the base being nearly as great as that across the middle, the axal
furrows curving inward only very slightly behind the middle.
The height is equal to about half the length. The frontal lobe is
very short, being only about one-fourth the length of the glabella,
owing to the forward position of the first lateral furrows. These
furrows, which arise almost at right angles to the axal furrows and
opposite the ‘terminal pit,’ are curved gently backward, and their
free ends are separated by an interval at least twice as great as
their length. They are only faintly marked and narrow.

* Schmidt, ‘ Rev. d. ostbalt. Silur. Trilob.’ pt. i. p. 171, pl. x. figs. 1-4, &

pl. va figs. 22-27, Mém. Acad. Imp. Sci. St. Pétersb. ser. 7, vol. xxx. (1881)
no. l.

422 MR. F. R. COWPER REED ON THE» [Aug. 1896,

The second lateral furrow is situated halfway between the first
and third lateral furrows. Like the first, it is curved gently back-
ward and is faint and narrow. It does not exceed the first in
length, and runs parallel to it.

The third side-furrow is much stronger and deeper, and curves
more strongly backward towards the neck-furrow. It does not,
however, reach the latter, and only a weak groove even in the casts
appears to connect the two. ‘The basal lateral lobes thus defined
are rhomboidal in shape, do not rise above the general convexity
of the glabella, and are separated by an interval equal to their own
width.

The axal furrows are distinct and well marked, but not so broad
as in Ch. (Ps.) conformis. The neck-furrow is stronger and broader
than the axal furrows, and curves forward in the centre at the base
of the glabella. The neck-segment is rounded, and has a width
equal to about half the length of the basal lobes of the glabella.

The cheeks—the fixed portion is alone preserved in the Keisley
specimens—bend down steeply on each side, with a convexity from
back to front, and are scarcely at all elevated. The furrow marking
off the neck-ring is distinct, and curves forward at the genal
angle to pass into the broader marginal furrow. The genal angle
is produced into a short, triangular spine, backwardly and slightly
outwardly directed. The width of the cheek is considerably less
than one-third of the total width of the head-shield, and this is a
marked and important feature.

The anterior branch of the facial suture cuts the front margin of
the head-shield nearly at the level of the first lateral furrow of the
glabella, and thence runs backward parallel to the axal furrow of
the eye. The posterior branch curves outward and backward from
the eye, at first nearly parallel to the posterior margin, to cut
the lateral margin a short distance in front of the base of the genal
spine—nearly at the level of the third lateral furrow of the glabella.

The small eye is situated opposite to the second lateral lobe of
the glabella, and approximately on the highest portion of the cheek.
The eye-lobe rises up steeply from its base, and is there separated
from the surface of the cheek by an oblique groove.

There is a broad and short ‘frontal limb’ in front of the glabella
as figured by Schmidt (op. cit.) in Ch. (Ps.) hemicraniwm.

The whole surface of the head-shield is ornamented with small
tubercles, not closely set, and the cheeks have in addition small
pittings.

The points of difference between this form and Ch. (Ps.) hemi-
cranium are: (1) the greater breadth of the glabella in proportion
to the head-shield; (2) the smaller breadth of the head-shield ;
(3) the subquadrate shape and greater convexity of the glabella;
(4) the more forward position of the point of section of the lateral
margin by the facial suture. In all other points the two species
seem to agree very closely.

In size the Keisley form is about double that of any of the Russian
specimens of Ch. (Ps.) hemieranium. One of our head-shields of

Vol. 52.] FAUNA OF THE KSISLEY LIMESTONE. 423

Ch. (Ps.) subyuadratus measures 17 millim. in length and 32 millim.
in width ; the glabella of this specimen measures nearly 15 millim.
in length, and the breadth is the same across the middle and 13
millim. at the base. The largest specimen that 1 have seen has a
head-shield 23°5 millim. in length, but most of them range between
16 and 18 millim.

Note.—A hypostome found unconnected with any head-shield
shows some new features, though on the whole it resembles that of
Ch. (Ps.) hemicranium figured by Schmidt. It may therefore not
improbably belong to this new species Ch. (Ps.) subquadratus. In
shape it is broadly ovate, obtusely pointed behind and rounded in
front. The central area, which is slightly but regularly convex,
has parallel sides and a truncated frontend. <A rather deep furrow
surrounds this area and marks off a tumid border with an average
width of about one-sixth of the central area. This border is
thickened and more elevated at the posterior end of the hypostome,
but at the anterior end it is indented by a deep notch on each
side, and produced into a tapering ‘ ascending process’ with a broad
base as in typical species of Cheirurus. The whole surface of the
hypostome is granulated, and on the convex central area are also
some scattered pits. The length of the hypostome is 8°5 millim.,
and the breadth 7 millim. across the middle.

SPHROCORYPHE GRANULATA, Angelin?

A small globular glabella showing a little nodular lobe at the
base and a portion of the fixed cheek corresponds, so far as these
fragmentary portions permit determination, with Angelin’s species
Sph. granulata.* The ornamentation of the surface is also similar.

SPH £ZREXOCHUS MIRUS, Beyr.

There occur in the Keisley Limestone numerous heads exactly
like those of this well-known trilobite. I have seen only oné typical
pygidium from this bed, and it is quite probable that. some of the
heads belong to the species I have called Sph. latirugatus, for the
pygidia of this latter species are associated with the heads of the
so-called Sph. mirus. I am unable to make two species out of the
head-shields, though variations in the distance apart of the basal
lobes, etc., do occur, as Salter himself has remarked.

SPHZREXOCHUS LATIRUGATUS, sp.n. (Pl. XX. fig. 12.)

A pygidium has recently been found which, while undoubtedly
belonging to the genus Spherewochus, presents many points of
difference from the common British species Sph.mirus. It resembles
Lindstrém’s * Sph. laciniutus more closely than any other species

‘ Angelin, ‘ Palzont. Scand.’ 1854, p. 76, pl. xxxix. fig. 4; Schmidt, ‘ Rev.
d. ostbalt. Silur. Trilob.’ pt. i. pl. viii. figs. 17-19, p. 169, Mém. Acad. Imp. Sci.
St. Pétersb. ser. 7, vol. xxx. (1881) no. I. “A

2 Lindstrom, ‘ Forteckn. p& Gotl. Silur. Orustae.’? Ofy. k. sv. Vet.-Akad.
Forhandl. 1885, no. 6, p. 47, pl. xiii. fig. 6.

Q.J.G.8. No. 207. 26

424 MR. F. R. COWPER REED ON THE [Aug. 1896,

that I know, particularly in the raised ridge-like ribs, the wide
interpleural grooves, and the elongated axis.

The Keisley pygidium is about twice as wide as it is long.
The axis is less than one-third the width of the pygidium at its
anterior end, and is triangular in shape. It is convex and more
elevated than the lateral lobes, but decreases in height posteriorly.
Its length is twice as great as its width at its anterior end. It is
composed of three segments: the first two form two prominent
rounded rings, separated by a wide deep groove; the third segment
is marked off from the second by a somewhat wider groove of the
same depth, and consists of an elongated triangular piece with a
pointed posterior end and sides converging at an angle of about 50°.
It is as long as the whole anterior part of the axis, and its pointed
extremity just touches the concave posterior margin of the pygidium
between the third pair of ribs.

The axal furrows are not deep, but are distinct, particularly along
the sides of the terminal segment.

The lateral lobes are almost flat and horizontally extended ; they
are rudely triangular in shape, and have the margins scalloped owing
to the projection of the rib-ends. The anterior edge is not so
strongly curved back as in Sph. laciniatus (Lindstr.), nor is the
fulcrum so distinct, but the edge is similarly formed by the rounded
prominent first rib, which is continued with equal strength to’ the
lateral angle at which it projects with a rounded extremity. The
second rib, corresponding to the second axal ring, forms a similar
prominent rounded ridge on the lateral lobe, but curves backward
rather more strongly and increases slightly in width. It projects,
like the first rib, beyond the pygidial margin.

The wide, shallow, concave depression separating it from the first
rib is more than twice as wide as the ribs themselves on the margin.
Owing to the projection of the extremities of the first and second
ribs, the margin makes a re-entrant angle between them.

The third pair of ribs are almost parallel to each other, and run
straight backwards as low rounded ridges expanding posteriorly.
They start from the anterior end of the terminal axal segment, and
form rounded projections on the posterior margin of the pygidium.
They are separated from the second pair of ribs by a wide shallow
groove, rather wider than the ribs themselves, and from the terminal
axal segment by a similar groove of rather less width.

The pygidial margin between the extremities of the second and
third pairs of ribs forms a wide rounded re-entrant angle, and
between the ends of the third pair of ribs themselves a slight re-
entrant curve. In Sph. laceuatus this curve is much narrower and
stronger.

It is probable, as mentioned above, that some of the head-shields
called Sph. mirus in the Keisley Limestone belong to this new
species, but, in the absence of any distinct features by which to
separate them, it is impossible to be certain. The exact agreement,
so far as I can see, of the head-shields with those of Sph. mirus
makes one suspect that the specific difference may be capable of
detection only in the pygidia.

Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 425

It is, however, impossible to express a decided opinion until we find
indubitable evidence that some of the so-called Sph. mirus-heads of
the Keisley Limestone belong to the new species latirugatus.

It is noteworthy in this connexion that only one typical Sph.
mirus-pygidium has been found at Keisley, whereas fragments of
the Sph. latirugatus-pygidium are not very uncommon.

millim.
Penesthiol PyeidMy, co. desswsescslewselesedooasedcess
Breadth Say CRP er eee tay eee eee 15

Some other less perfect specimens must have been longer in
proportion to their breadth.

Note.—Salter (Geol. Surv. dec. vii. 1853, pl. iii. fig. 15) figures a
tail of this new species from Kildare, but includes it with Sph.
mirus, though with the remark that it is ‘more elongated than
in the Dudley specimens.’ I have seen several specimens from
Kildare agreeing with the above description.

SravRocEPHALUS Murcuison1, Barr.

This genus has not previously been recorded from the Keisley
Limestone, but I was fortunate enough to obtain more than half a
dozen specimens of the head-shield during a recent visit. They
occurred in the same blocks with many of the characteristic Keisley
Limestone fossils, so that no doubt can be entertained that they
belong to this horizon.

Their identification with Barrande’s species is rendered specially
easy, since in the Woodwardian Museum is a head of Stauwrocephalus
from Rhiwlas (figured by M‘Coy) which Barrande himself examined
and held was indistinguishable from his Bohemian species,’ Our
Keisley specimens show all the typical features, though unluckily
the free cheeks are not preserved. The position of the eye at once
distinguishes this species from St. globiceps (Portl.), figured and
described carefully by Salter.*

ACIDASPID&.

ACIDASPIS CONVEXA, sp.n. (Pl. XXI. fig. 6.)

The genus Acidaspis has not previously been recorded from the
Keisley Limestone, but I have recently found two fairly good head-
shields presenting characters which prove that they belong to this
genus, and to a new species.

The head-shield of this new form is very convex from back to
front, and also, but to a less extent, from side toside. The glabella
shows a median convex portion of cylindrical shape, with parallel
sides and more than twice as long as wide. This central portion of
the glabella forms the crest of the head-shield, and its apex is nearer
the front than the hind border. The anterior end is lofty, steep,
and abrupt, but the posterior end slopes more gradually down to the

1 It is mentioned by Barrande in ‘ Syst. Sil. Bohéme,’ vol. i. (1852) p. 812,
pl. xliii. fig 28.
* Mem. Geol. Sury. dec. xi. (1864) pl. v. fig. 6, p. 3.
262

426 MR. F, R. COWPER REED ON THE [Aug. 1896,

level of the less elevated neck-ring. There are two distinct pairs
of lateral lobes of very unequal size. ach of the lobes of the basal
pair is elliptical in shape, obliquely directed forward and outward,
and is separated from the median portion of the glabella by a strong
furrow. The middle pair of lateral lobes consists merely of two
small circular nodules situated rather more than halfway forward
towards the front end of the glabella. There are slight indications
of a first pair of lateral lobes.

The inner portion of each fixed cheek rises into a semilunar
rounded ridge embracing the side of the basal and middle lobes of the
elabella, but not elevated to more than half the height of the basal
lobes and separated from them by the curved axal furrow. At the
posterior end of this rounded ridge, and shghtly towards its outer
side, is a small oval nodule. The outer portion of the fixed cheek
is small and apparently flat, with its posterior margin curving back-
ward. he facial suture runs backward and obliquely outward
to the small rounded eye-lobe, and thence in the same direction to
the posterior margin of the head-shield so as to cut it at an angle of
about 45°. The eye is situated rather behind the middle of the
glabella, at the end of a low ridge which traverses the flat outer
portion of the fixed cheek with a slightly oblique course.

At the base of the axal furrow on each side of the distinct neck-
furrow is a small rounded nodule lying behind the basal lobes of the
elabella. The neck-ring is rounded and rather wide for the size of
the head-shield, but apparently is not provided with an axal spine.
A narrow neck-segment is discernible behind the fixed cheek, and
by its backward curvature seems to indicate that the genal angles
were furnished with spines. The surface of the head-shield is finely
tuberculated. The free cheeks are unknown.

millim,
Weneth of naiddlershueld! ye ssseceeeemee cece: vse eocce eens 3°0
Wradith of dio, ab! base. ®. : .saa-eee a eeerettectecnnk < oaus «autede «ah ‘
Greatest height (close to anterior end of glabella) ...... 2:0
Meneth of glabellla, ...::.s:cceeee ease yee eee een te 2-0
Width of/do, at base: .....ccesauanemmesenteee sii skis sireGelekiace 15

Barrande’s species, Acidaspis minuta, from Etage E bears a close
resemblance to this Keisley form, but in the Bohemian species the
middle lateral lobes of the glabella are oval and much larger, and
are situated nearer the anterior end of the glabella. The spevies
described by Tornquist * as A. evoluta from the Leptena-Limestone
is closely allied, but it differs in the larger size of the second lateral
lobe, and the greater width of the glabella. The outer portion of
the fixed cheek and facial suture are moreover not figured.

ACIDASPIS, sp.

A fragment of the head-shield of an Acidaspis in the Carlisle
Museum shows some peculiar features, but it is not sufficiently well
preserved to enable us to assign it to any known species or to

1 Tornquist, ‘Undersokn. fy. Siljans. Trilob.’ Sver. geol. Undersokn, 1884,
p- 28, pl. i. fig. 24.

Vol. 52.] FAUNA OF THE KEISLEY LIMESLONE. 427

describe it as a new one. The base of a parallel-sided cylindrical
glabella is seen with a pair of very narrow elongated basal lobes
pressed close against its sides. These lobes do not measure in width
more than one-third of the width of the glabella. Outside each of
these lobes is a broader, rounded, swollen ridge, running forward
and curving slightly inward. At the base of the axal furrow which
separates this ridge and the basal lobe is a deep pit. The narrow
neck-lobe at the base of the glabella is furnished with a very strong
central tubercle.

millim
1 TET] eS e ERSSPR ee St 2'5
LURES TG a] OL Pie aN 3 ala dina oi bhi Miah Aa CU aren. ee 4:0

Licwapa.
Licuas naxatus, M‘Coy.

One extremely sharp cast of the pygidium of this well-known
species shows all the typical features, which need no description.

Licuas AFrinis, Angelin.

The occurrence of this characteristic species of the Leptena-
Limestone in the Keisley Limestone is established not only on the
evidence of a head-shield, but also on that of several pygidia, of
which one, fairly well preserved, is in the Woodwardian Museum.
Angelin’s' original figures and description were inadequate and
unsatisfactory, but by means of Tornquist’s* more recent diagnosis
and illustrations, and by comparison with actual Dalecarlian speci-
mens, I have no doubt of the correct identification of the English
individuals.

Measurements.

millim
Length of median lobe of glabella ..............ececeeeees 15°0
Width of do-acrOss atiterior Gnd ii j..hieecssih A tenses es 16:0

Width of do. at the level of the posterior end of the
POU ILC Ie 0S peter A NE BPS ek TTL oan ne 6:0
eRe OMOL AES ICAU. Geisec..<cdastsadwakaeleewnsaatene'e 10-0
“NUTS UNL CAPPUG) Oh ee Re Se eer i Ce a ea 6:0
Length of pygidium (so far as preserved) ............44 240
Estimated length of do. when perfect................0006+ 38:0
Width of do. along anterior edge ...........se0eeeeee renee KO)
Width of do. at level of axal knob ...............ccceeeees 44.0
Wyaueon axis at anterior end |. .......0.../cc0ccessseoeer se 13:0
Width of do. at end of axal furrows ..........cccceeeeeee 6°5
Length of do. to end of axal furrows ..............s000005 13-0
Greatest width of post-axal area ..........cscescesceseeeees 11-0

LicHas CONFORMIS, Ang., Var. KEISLEYeNSIS, nov. (Pl. XXI. fig. 10.)

For the determination of this species we have again to rely upon
a single imperfect specimen of a pygidium and on Angelin’s figure
and brief description,’ Since the Swedish and Keisley forms agree

' Angelin, ‘ Palxont. Scandin.’ 1854, pl. xxxviii. fig. 4, p. 69.

* Tornquist, ‘ Undersokn. éfy. Siljans. Trilob.’ Sver. geol. Undersdkn. 1884,
pl. i. fig. 31, p. 33,

° Augelin, op. supra cit. pl. xxxviii, fig. 5, p. 74.

498 MR. F. R. COWPER REED ON THE [Aug. 1896,

completely, except in three trifling details, there is not sufficient
reason to institute a new species. The three points of difference
are: (1) the point of origin of the oblique furrow on the second
pleura ; (2) the length of the axal furrows; and (3) the more abrupt
posterior truncation of the axis in the British form. But I do not
consider these differences to be of more than varietal importance.

The axal furrows are fairly well marked on each side of the axis,
though at its posterior end they curve inwards, become less distinct,
and do not quite meet in the centre, thus leaving the axis at
its apex undefined and continuous with the post- -axal area. In
Angelin’s figure of L. conformis the axa] furrows pass over com-
pletely into the furrows marking out the sides of the post-axal
area, and do not bend inwards round the extremity of the axis.

In the case of the second pleura a furrow traverses the pleural
surface parallel (for the greater part of its length) to the hind border,
but dies out before reaching the free point of the pleura. In
Angelin’s L. conformis the pleural furrow has a more central
position on the surface, and originates at the middle point of the
base.

Measurements.

iemethvot Pyeidium %.....c:ccccceeeereeeee rene ae os bce neeneee 24.
Greatest width of do. at level of proximal end of second
imtenplenural furrow. st cseemeeeetees ase aeo--ee re tose cake

Wenge th tol axis. ie..02h gcnestee caterer ahstedoe sce aeen ee ace 10
Wadth of anterior end of Cosueeca a. ecnecces eee eee 10
Wength’of post-axal area. eeamee cn: eee <- onsen eee 14
Width of anterioriend ol Goumeen eee cee ce eee eee 7
Width of middleot dost eene Carta ene- covcececneere 5

LicHAs HIBERNICcUS, Portl.

The occurrence of this species in the Keisley Limestone is another
proof of the close affinity of its fauna with that of the Kildare
‘Bala’ Limestone. A glabella with the median and large lateral
lobe well preserved has been found at Keisley. It exhibits the
typical characters of the species. So far as one can judge from
Schmidt’s* figures and descriptions, there is every reason to
consider his L. Holmi identical with Portlock’s species.

Licwas BuLpicers, Phill. MS. (Pl. XXI. figs. 8, 8a, 86 & 9.)

This species is represented in the Woodwardian Museum by a
very perfect middle shield and by a fragment of another.

The middle shield is strongly convex in an antero-posterior
direction, the anterior half curving down steeply in front to the
margin. From side to side across its middle the convexity is
slight, but uniform ; the posterior halfis flattened. The outline of
the anterior margin of the head-shield is semicircular.

The glabella has all its lobes well developed. The frontal

1 Mém. Acad. Imp. Sci. St. Pétersb. ser. 7, vol. xxxiii. (1885) no. 1: ‘ Rev.
ostbalt. Tril.’ pt. ii. p. 54, pl. vi. figs. 14 & 15.

Vol. 52.4 FAUNA OF THE KEISLEY LIMESTONE. 429

(= median) and anterior side-lobes each have a gentle independent
convexity of their own, but are somewhat flattened towards their
posterior ends. The middle and posterior side-lobes are flattened,
and do not rise above the common flattened surface of the posterior
half of the glabella. The cheeks curve down on each side with a
slight convexity of their own.

A front view of the head-shield shows a gentle median upward
curve in the anterior edge forming a shallow bay, as in L. verrucosus,
Kichw. A narrow rounded border runs round the anterior margin
and is separated from the glabella by a shallow marginal furrow
passing laterally into the axal furrows. ‘The latter, and all the
glabellar furrows, are well marked and of equal depth.

The anterior glabellar side-furrows curve at first strongly inward,
but then run backward with a convergence of about 30° for more
than two-thirds the length of the glabella ; then they bend sharply
outward and forward at an angle of 60° to their former course to
form the incomplete middle side-furrows. These middle side-
furrows become suddenly faint about the middle of the base of
the anterior glabellar side-lobes, but are traceable into the axal
furrows. The posterior side-furrows are short and straight, and
form the direct lateral continuation of the straight median portion
of the neck-furrow, so that the glabella here appears crossed by a
single straight horizontal furrow, as in L. verrucosus, Eichw. This
horizontal furrow mects the axal furrows at right angles. The
neck-furrow on each side of the point of union with the posterior
side-furrows of the glabella bends sharply backward, so as to define
the basal glabellar lobe.

The axal furrows start from the point of junction of the marginal
and anterior side-furrows, and a small pit is here situated. From
this pit the axal furrows run backward, curving outward in a
convex bow at the point where the ‘eye-furrow’ branches off.
Thence they curve inward with an uniform gentle concavity, and
thus reach the neck-furrow; but opposite the middle and basal
glabellar lobes their curve is slightly distorted and pushed outward.

The frontal or median lobe of the glabella, from its front end to
the level of the middle side-furrow, reaches over two-thirds the
length of the head-shield. It has a marked convexity of its own,
particularly strong in its front part. The anterior downward slope
of its front end commences about halfway between the neck-furrow
and the anterior margin. The width of its front end is nearly three
times as great as the width of its posterior end at the level of the
middle side-furrows. The anterior lateral angles of this median
or frontal lobe are bluntly pointed, and overhang the anterior side-
lobes to half their width.

The anterior side-lobes are roughly elliptical in shape, but their
ends are somewhat pointed. The middle side-lobes have a sub-
quadrate appearance, owing to their posterior outer angle being a
right angle and the third side-furrow being straight. They are
not marked off from the middle portion of the glabella either by
a furrow or by possessing an independent convexity. They are

430 MR. F. R. COWPER REED ON THE [Aug. 1896,

nearly half the length of the anterior side-lobes. The basal lobes
are distinct, and form right-angled triangles with an inner angle of
rather over 30°. Measured along the axal furrow their length is
quite three-fourths that of the preceding side-lobe.

The neck-segment is rounded and convex, somewhat raised
behind, and broadest in its middle portion behind the horizontal
part of the neck-furrow ; on each side of this it decreases gradually
in width to the axal furrows.

The fixed cheeks are only partially preserved. Their anterior
pointed end reaches forward only so far as the middle of the
glabella. The palpebral lobe, or rather band, runs as a narrow
rounded border along the outer edge of the fixed cheek, but it is
badly shown in our specimens; it extends forward around the
front end of the anterior side-lobe of the glabella, to pass into the
true anterior margin at the point of union of the axal, marginal,
and first side-furrows. The palpebral band is marked off by a
shallow furrow—the eye-furrow—from the rest of the fixed cheek,
just as in L. angustus, Beyr., and L. Hichwaldi, Nieszk.

The whole surface of the middle shield is thickly studded with
tubercles of various sizes.

Measurements. 17:
millim
ength of plabelia re csisc-<ce=sa0s-~ eee eceetenees Meee ne 12°5
Breadth of glabella at middle side-furrows ............ 11-0
o base (between posterior ends of
axal furrows)itecs. snes te acee ote ne ibe ecb aes 14:0
Breadth of fronton trontal lobe c.cssteses-e- gees ooo nesaee 10:0

There is a fine specimen from Kildare in the Woodwardian
Museum ; and in the Museum of Practical Geology, Jermyn Street,
are two specimens of head-shields from the same locality and lime-
stone. With one of these head-shields is mounted on the same
tablet a very peculiar pygidium of a Lichas unlike any found at
Keisley, with a long axis with four rings and a terminal piece
nearly z the width of the pygidium and “fully 2 2 its length; the
three pairs of pleure are short and broad, ae long free points.
This tablet has a label with the name Lichas bulbiceps, Phill. MS.,
and it was catalogued in 1865 with this specific name. Another
tablet with a similar head-shield, but the utterly different pygidium,
which I have called L. bifurcatus, is also labelled L. bulbiceps, MS.,
and bears the note, ‘identical with Gaspe’s species, Logan.’ This
also is entered in the 1865 catalogue as L. bulbiceps. Mr. EK. T.
Newton thinks that the specific name was given by Salter, but no
description or further reference to the fossil can be found. From
the name itself the species was no doubt founded on a head-shield,
and so I think it is as well to retain this name for the head-shield
which I have described above. But since there is a doubt whether
either of the pygidia mounted with the head-shields in the Jermyn
Street Museum really belongs to the same species, I prefer to call
the one there on tablet 7, flat case 5 (p. 39 of Cat. Camb. Sil.
Fossils, 1878), by a new name—L. bifurcatus (q. v.).

Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 431

Affinities. —The Keisley species L. bulbiceps resembles L. verrucosus,
Hichw., in the general arrangement and relations of the different
lobes and furrows, but it differs(1) by having a relatively much
shorter head-shield ; (2) by possessing a much greater convexity
than that species; (3) by the flattening of the posterior portion of
the middle shield ; (4) by the larger size and triangular, instead of
elliptical, shape of the basa] lobes of the glabella ; (5) by the angle
of convergence of the anterior side-furrows of the glabella; (6) by
the concave curvature and greater length of the axal furrows
between the middle side-furrow of the glabella and the neck-
furrow.

Note.—A hypostome of a Lichas with many points of resemblance
to the hypostome of L. verrucosus probably belongs to L. bulbaceps.
It is subquadrate in general outline, and is nearly as broad as it is
long. It consists of a median swollen rounded portion, subcircular
in outline and sharply marked off by a deep furrow from the border
above which it is raised. It is notched near its posterior end by a
pair of short, deep, oblique lateral furrows which are directed back-
wards. Its surface is ornamented with small but distinct tubercles
of equal size, arranged with some degree of regularity. The border
surrounding this central portion is very narrow in front, but
expands at the anterior lateral angles into short, bluntly pointed
‘anterior wings, behind which the sides of the hypostome run
back parallel to each other. The border increases in width, and has
its edge slightly turned up and rounded as far as the posterior end
of the median portion, behind which it expands and has its edge
bent downward. This hinder portion of the border is ornamented
with a series of striz parallel to the lateral margin. The posterior
side of the hypostome is excavated so as to appear forked, and
immediately behind the median portion the border attains its
greatest width, and is raised into a low prominence. The length
of the hypostome is a little over 6 millim.

LicHAS BIFURCATUS, sp.n. (Pl. XXI. fig. 7.)

It seems inadvisable to regard the pygidium on which this species
is founded as belonging to L. bulbiceps, for no species allied to the
latter has a pygidium with such characters. The pygidia rather of
such species as L. triconica (Dames) and L. margaritifer (Nieszk.),
with their forked extremity, approach most closely to it.

Our pygidium is about one and a half times as broad as long; its
shape is almost parabolic, but it is pointed and forked posteriorly.

The axis occupies the middle third of the width of the pygidium
and extends for nearly half its length. It is strongly convex, and
tapers gradually to its posterior end, which is truncate, abrupt, and
steep. The articulating ring on the front end is broken off, but
there are three rings crossing the axis, the first of which is strong,
narrower at the middle than at the sides, and marked off by deep
wide furrows behind and before. The second ring is very similar
to the first, and the third, which is of more uniform width, is defined
posteriorly only by a faint furrow.

432 MR. F. R, COWPER REED ON THE [Aug. 1896,

The lateral portions of the pygidium are flat and horizontally
extended in one plane. All the furrows are of equal strength. The
anterior pair of pleure is very imperfectly preserved; only the
base is visible, but this part is seen to be equal in width to the first
two axal rings. The diagonal furrow across its surface starts from
nearly the middle of the base. From comparison with allied forms
it is probable that this first pleura ended on the margin in a short,
backwardly-directed, free point.

Tbe second pleura has the same basal width as the first, but.its
posterior limiting-furrow starts behind the faint posterior limiting-
furrow of the third axal ring. This pleura expands in width in
the middle, and then contracts to end in a very short recurved point
which scarcely projects bejond the margin. The posterior limiting-
furrow of this pleura runs in a straight line to the pygidial margin
at an angle of about 45° to the median line of the axis. The
furrow traversing the surface of this pleura starts from the anterior
angle of the base and runs parallel to the posterior edge of the
pleura, but bends round sharply at its outer end to reach the
recurved point.

The third pleura is almost a right-angled triangle, the hypotenuse
being the posterior or rather inner limiting-furrow, which is a
continuation of the axal furrow. The free terminations of this
third pair of pleuree form the short approximate points of the
posterior end of the pygidium, which give it its forked appearance.
The surface of each pleura of this pair is crossed by a furrow which,
starting from about the middle point of the base, runs backward
nearly parallel to its fellow and to the median line of the axis, but
with a very slight outward curvature. After traversing more than
three-fourths of the pleura it becomes faint, and curves round
rapidly inward to join the posterior limiting-furrow, thus circum-
scribing with the latter a lanceolate area, as in L. lawatus and
others.

The axal furrows are distinct, and are continued directly into the
posterior limiting-furrows of the third pair of pleure. These latter
furrows are straight, and converge posteriorly at an angle of 20° for
more than three-fourths of their length—~. e. to the point where the
diagonal furrow of the third pleure joins them. Behind this point
they become fainter and converge twice as rapidly as before to meet
each other at the fork between the free ends of the last pair of
pleure. The flat post-axal area between them has therefore a
tapering and peculiar shape.

The whole surface of the pygidium is covered with tubercles of
medium size, with smaller ones interspersed.

Measurements.
millim.
Len ey Of pyeidimm [oe eeeee-meeee-eare-ceero-u= mentees 9-0
BRIS» + faescare NRE cy Aa re eM chctite Msi GlcsciSiceorcxe otetaye Stare 4:0

Vol 52:] FAUNA OF THE KEISLEY LIMESTONE. 433

Affinities.—The pygidium of LZ. margaritifer (Nieszk.)* very
closely resembles the one above described. The forked extremity,
the three rings on the axis, the course of the axal furrows with their
ends bending out to define the lanceolate areas on each side of the
post-axal area, the projection and shape of the two anterior pairs
of pleuree, and the general form of the pygidium are points of
similarity. The most conspicuous point of difference is the con-
tinuation of the axal furrows to the fork, which gives a very marked
appearance to this portion of the py gidium i in the Keisley form, and
is in my opinion sufficient to separate it off as a distinct, though
allied, species.

L. margaritifer occurs in the Borkholm Beds (F2) in East Russia,
and the occurrence of this English representative form L. bifurcatus
in the Keisley Limestone is another link between the 7 of the
two beds.

PROETID#.

CyPHASPIS Cre: subgen. nov.) NicHoxsoniI, sp.n. (Pl. XXI.
figs. 3 & 3.4.)

There are four specimens of this new form in the Woodwardian
Museum Collection,” but in three cases the central portion only of
the head-shield is preserved, while in the fourth case the head-
shield has one free cheek attached, though slightly shifted out of
its natural position.

The description of this species is as follows :—Head-shield nearly
semicircular, gently convex, 3 millim. long. Glabella broadly ovoid,
slightly and gradually narrowing towards the rounded anterior end.
Width at base nearly equal to length. Length equals about three-
fifths that of the head-shield. Glabella uniformly semicylindrical
in shape, rounded off in front.

The base of the glabella occupies nearly one-third of the distance
between the points where facial sutures cut the hinder border of the
head-shield. The glabella possesses no basal lobes nor side-furrows.

Axal furrows well marked, of constant depth and width, uniting
in front of the glabella, where at the median point of union a short
groove runs forward notching posteriorly the convex frontal area,
but not traversing it. At the antero-lateral angles of the glabella,
where the axal furrows curve inward round its front, there is on
each side a similar but longer groove running outward and slightly
forward over the swollen fixed cheek to the line of the facial suture,
and separating the frontal area from the fixed cheeks proper. This
triradiate group of grooves is a conspicuous feature of the head-
shield.

Neck-furrow well marked, of the same width and depth as the
axal furrows. The neck-lobe measures from back to front, across
its middle, about a quarter the length of the glabella, but does not
rise to more than half the height of the latter. Behind the fixed

Nieszkowski, ‘ Monogr. d. Trilob. d. Ostseeprov.’ Archiv f. Naturk. Liv.

Est. u. Kurl. ser. 1, p. 568, pl. i. fig. 15.
2 There is another specimen (labelled Agnostus) in the Carlisle Museum.

434. MR. F. R. COWPER REED ON THE [Aug. 1896,

cheeks the neck-segment diminishes to about one-half the breaduh
and height of the neck-lobe. The fixed cheeks are produced as
regularly swollen ‘anterior wings,’ on each side of the glabella, and
these wings are about as wide as the glabella. In front of the
glabella they unite and constitute the convex frontal area, which is
as high as the ‘ anterior wings’ but wider, and has, like them, a
steep inner or posterior, but gentler anterior or outer slope.

The facial sutures cut the front margin of the head-shield at a
distance one from another equal to about 13 times the basal width
of the glabella. Each runs at first backward and slightly inward
to the antero-lateral groove, which separates the frontal area from
the anterior wing of the fixed cheek; then it takes a slight outward
trend to the eye-lobe, which is very indistinct in our specimens;
from this point it makes a sudden bend outward so as to become
nearly parallel to the hind border of the head-shield, finally bending
sharply backward to cut the margin.

What appears to be the free cheek (badly preserved) is triangular
in shape and not swollen ; it bears a large, smooth, ovate eye, which
hes a little behind the middle of the glabella and at the sharp
re-entrant angle of the facial suture. The genal angle appears to
have been produced into a spine.

The front and sides of the head-shield are surrounded by a narrow,
smooth, raised, rounded border, separated from the frontal area and
free cheeks by a marginal furrow, which is nearly as wide as the
axal furrows.

The whole surface of the head-shield is covered with fine granu-
lations and scattered tubercles of various sizes without any definite
arrangement, but the middle point of the neck-lobe of the glabella
is generally marked by a specially large isolated tubercle.

The thorax and pygidium are unknown.

Affinities.—The close resemblance to Tornquist’s Trilobites trira-
diatus * which our Keisley form bears led Messrs. Marr and Nicholson*
to compare it with that species; but on a minute examination of
our specimens by the side of Tornquist’s figure and description, I
am convinced that they must be considered distinct. The shorter
length, more rounded and ovoid outline, and greater width of the
glabella; the absence of the pair of notches or short furrows at its
base; the non-continuation of the median notch as a groove over the
frontal area; and the more rounded and swoilen character of the
anterior wing of the fixed cheek, are the chief reasons which lead me
to this conclusion.

Tornquist’s species and ours are, however, very closely allied, and
present in common important features, which mark them off from
a typical Cyphaspis, namely, (1) the absence of the basal lobes to the
glabella; (2) the presence of the three radiating notches or grooves
at the front end of the glabella.

1 Tornguist, ‘ Undersokn. ofy. Siljans. Trilob.’ Sver. geol. Undersokn. pl. iii.
_ fig. 18, p. 92.

2 Marr & Nicholson, ‘The Cross Fell Inlier,’ Quart. Journ. Geol. Soc.
vol. xlvii. (1891) p. 507.

Vol. 52.] ° +‘ FAUNA OF THE KEISLEY LIMESTONE. 435

These characters necessitate, in my opinion, the creation of a
subgenus of Cyphaspis, which may appropriately be termed 76rn-
quistia. Our Keisley form may aptly bear the specific name
Nicholsoni, in honour of its discoverer, Prof. H. A. Nicholson.

Cypuaspis ? Harkness, sp. n. (Pl. XXI. fig. 2.)

Glabella conical, gently convex, elevated above cheeks, tapering
gradually towards its rounded anterior end, which apparently
reaches the front margin of the head-shield. A pair of incom-
pletely defined basal lobes is present. No other lobes or traces of
furrows on the glabella. The furrow which partially defines the
inner side of each basal lobe runs from the neck-farrow forward and
inward for a short distance as a faint groove, making an angle of
about 60° with the neck-furrow ; then it suddenly bends round ata
right angle to its previous course, and-runs in a straight line out-
ward and forward with increased strength, to end abruptly in a
sort of pit before reaching the axal furrow. ‘There is a similar
expansion and depression at the bend in its course. The basal lobes
thus marked off are subcircular in shape, nearly half as long as the
glabella, and about one-third of its basal width, gently convex, but
not rising above the rest of the glabella, though projecting slightly
on each side of it. Axal furrows distinct, but notdeep. Neck-lobe
of medium width, separated from the glabella by a very strong neck-
furrow. Posterior part of fixed cheek triangular in shape, flattened,
and gently bent downward; anterior wing imperfect, apparently of
sudilar shape, but smaller. The facial suture cuts the posterior
border of the head-shield at a distance from the axal furrow of less
than half the basal width of the glabella ; thence it runs forward and
inward with a gentle curvature towards the anterior end of the basal
lobe of the glabella. At this point, where the eye was situated, it
appears to curve away from the glabella with the concavity of the
curve forward, and cuts the front margin at some distance from the
axal furrow. Outline of head-shield only partially preserved, pro-
bably semicircular ; narrow rounded border visible. Whole surface
of head covered with tubercles of various sizes.

Measurements.
millim
MMP Gl MCAC-SHIGIG! 1055 sot. cdod oh sedend va poeded accion’ 12'5
Pe NLA Fo 55. ost ca wean sininre Balas ours bial webs 10:0
UME O GSU ASO. Uo ccecckn cus co cuiyssssmicpenencoed os 12:0
£ a LUSCH DUR) 0 2 ik 30016 le ip ee a a 9-0
Deneth Of Dasal lobes of doi... liieiiscsscseveststeseves 4:5

PHILLIPSINELLA PARABOLA, Barr.

Two glabellas of this species, with portions of the fixed cheeks
attached, have been found. There are also in the Woodwardian
Museum two pygidia, which correspond very closely with those
ascribed to this trilobite by Linnarsson, who called it Phillipsia,

1 Linnarsson, ‘Om Vestergotl. Cambr. och Silur. Aflagr,.’, K. svensk. Vet.-
Akad. Handl. vol. viii. (1869) no. 2, p. 72, pl. ii. fig. 32.

436 MR. F. R. COWPER REED ON THE [Aug. 1896,

This species has been recorded from the Haverfordwest area by
Messrs. Marr and Roberts,’ but this is the only mention of its
occurrence in Britain, so far as I am aware.

HARPEDID.
Harrses Wecetint, Ang.

Fragments of the head-shield of this large species are not very
uncommon in the Keisley Limestone, but I have not seen a glabella.
In all points the limb and genal portion with the narrow border
surrounding the head.shield agree with Angelin’s figures, and with
specimens from the Leptena-Limestone with which I have been
able to compare them.

Harpss costatus, Ang. ?

A portion of a head-shield of a Harpes appears to belong to this
species of Angelin,” for it shows the convex perforated limb, the
narrow striated border, and the convex genal portion with the
prominent eye-tubercle; but the glabella and other parts are not
preserved. Angelin’s species occurs in the Leptena-Limestone.

Harpers, sp.a. (PI. XXI. fig. 4.)

The posterior end of a very small trilobite consisting of a minute
pygidium with several thoracic segments attached, has recently
been found, and must be held to belong to the genus Harpes. The
portion preserved is in all only 2 millim. long, and a little over
4 millim. broad. The thoracic portion consists of horizontally-
extended pleurz in close contact with each other, and of a raised
convex axis. The pleure are narrow, flat, and rectilinear, with
parallel borders, and without any visible furrow. There is no
break between the thoracic and the pygidial portions of the speci-
men. The pygidium is transversely elliptical in shape, and has a
straight front edge and slightly rounded angles. Its axis is very
narrow, being only about one-fifth of the whole width of the
pygidium at its anterior end; it tapers very gradually posteriorly,
but is short, and does not reach the posterior margin. There are
two or three very faint rings on it, and just traces of ribs on
the lateral lobes.

Harpers, sp. 8. (Pl. XXII. fig. 5.)

Another pygidium of a Harpes of about the same size has been
found, with several body-rings attached. It resembles the one
above described in the character of the rectilinear pleure, the flat
horizontal lateral lobes of the pygidium, and the absence of any
furrow on the ribs; but it differs in the relatively broader axis and
its more rapid tapering, so that it terminates some distance from the
margin. The anterior end of the axis is nearly one-third the width
of the pygidium. At first sight it is almost impossible to say where
the thorax ends and the pygidium begins, for there is no marked
break in the series of eight or nine rings on the axal portion, nor

1 Quart. Journ. Geol. Soe. vol. xli. (1885) p. 476.
2 Angelin, ‘ Palzont. Scandin.’ 1854, p. 85, pl. xi. fig. 4.

Quart. Journ.Geol.Soc .Vol.LIl. Pl iS &

F.H.Michael del.et hth. Mintern Bros .imp.
Peto tos FROM .THE

KEISLEY LIMESTONE.

F.H.Michael del.et lith.

Quart. Journ.Geol. Sec . Voli LU Pl. Xa:

.
.
.
.
s
'

Mintern Bros.imp.

ieee eS ROM THE
Wee + LIMESTONE:

Vol. 52.] FAUNA OF THE KEISLEY LIMESTONE. 437

between the five or six pleure. By careful inspection, however, it
is seen that a terminal portion, consisting of two or three segments,
is bent down rather more sharply than the rest, as if composed of
one piece. This is the pygidium, with a very short axis—about one
half its entire length—crossed by two or three faint rings. The
breadth of the pygidium is about three times as great as the length.

EXPLANATION OF PLATES XX. & XXI,
PuateE XX.

. Illenus galeatus, sp.n. From above. Natural size.
Do. From the side. Natural size.

Do. Another specimen. From behind, Natural size.
. Lllenus Bowmani, var. brevicapitatus. Natural size.

I. Bowmani, var. longicapitatus. Natural size.

. lilenus, sp. Hypostome. Natural size.

. Cheirurus keislzyensis, sp.u. Natural size.

. Do. Pygidium. Natural size.

- Do. Hypostome. Natural size.

10. Ch. (Pseudospherexochus) subquadratus, sp.n. Natural size.
11. Do. Another specimen. X2. Showing fixed cheek.
12. Spherexochus latirugatus, sp.n. X2.

Puatse XXI,

Fig. 1. Ampyx binodulosus, sp.nu. X2.

2. Cyphaspis? Harknessi, sp.n. X2.

3. C. ( Térnquistia, subgen. nov.) Nicholsoni, sp.n. X4.
3a. Do. Probably free cheek. X83.

4. Harpes,sp.a. X4.

5. Do., sp. 6. x4.

6. Acidaspis convera, sp.n. X6.

7. Lichas bifurcatus, sp.n. X2.

8. L. bulbiceps, Phill. MS. From above. X2.
8a. Do. From behind. x2.

8b. Do. From theside. x2.

9. Do.? Hypostome. x38.
10. L. conformis, Ang. var. keisleyensis nov. X14.

Fig.

CO COMI D CB COBO

Discussion.

The PresrpEent congratulated the Author on his important dis-
covery, which, he said, proved that it was yet possible to add greatly
to faunas in comparatively well-known rocks. He asked whether it
was not possible that some of the smaller forms referred to were
merely young specimens of the large species. ,

Mr. R. 8. Herries enquired as to the horizon of the Keisley
Limestone.

Mr. Marr also spoke.

The AvurHor, in reply, explained that he had purposely employed
the name of ‘Keisley Limestone’ for the rock from which the
fossils had been obtained, because the question of its exact strati-
graphical horizon and of that of its much-disputed equivalents else-
where could not be discussed until its whole fauna had been de-
scribed. He could, however, by anticipation, say that the affinities
of its fauna were with that of the higher beds of the Ordovician,
and not with that of the Silurian.

438 DR. G. J. HINDE ON NEW FOSSILS [Aug. 1896,

21. Dxscrrprions of NEw Fossits from the CaRBoNIFEROUS LIMESTONE.
I. On PEMMATITES CONSTIPATUS, sp. nov., a Liraistip Sponen.
Il. On Patmacis HUMILIS, sp. nov., a NEW Purrorate Corat,
with Remarxs on the Gunus. III. On the Jaw-arparatus of
an ANNELID, Hunicites Reip1m, sp.nov. By Groreas JENNINGS
Hino, Ph.D., F.R.S., F.G.S. (Read April 29th, 1896.)

[Puates XXII. & XXITI.|

J. On PreMMATITES CONSTIPATUS, SP. Nov., A Lrratstip SponeE FROM
THE YOREDALE Beps or YorxsHire. (Pl. XXII. figs. 1, la—m.)

AtrnovcH the thick beds of chert in the Yoredale Series of North-
west Yorkshire are largely composed of the remains of siliceous
sponges, it is a matter of extreme rarity to meet with an entire
specimen of these organisms, and hitherto one has had to be con-
tent with describing the detached spicules of various forms with
which the beds are crowded. ‘The discovery therefore by Mr. J.
Rhodes of a fairly complete sponge in this series of beds is, in itself,
of some interest, and still more when the sponge proves on exami-
nation to belong to the genus Pemmatites, Dunikowski, a genus
which, up to fie present, has been known only from the Permo-
Carboniferous strata of Spitzbergen.

The sponge in question, of which only a single specimen has, as
yet, been found, is discoidal, oval in outline, having both upper and
under surfaces nearly equally convex, and the margins comparatively
sharp. There are no indications of a point of attachment on the
underside, nor any traces of a cloacal funnel or depression on the
upper. It is 63 mm. in length, 48 mm. in width, and 22 mm. in
thickness.

The canal system is very faintly shown; but on the convex
upper surface there can be traced canal-apertures, about 0°5 mm.
in width, disposed in rows extending from near the centre to the
margins (Pl. XXII. fig. 1). These appear to be the openings of
excurrent canals, which radiate from near the basal central portion
of the sponge in an oblique direction to the upper surface. No
incurrent canal-apertures can be recognized on the surface of the
sponge, but in thin sections canals about 0-16 mm. in width, bounded
by spicules, are shown here and there, which may possibly belong
+o an incurrent system. (Pl. XXII. fig. 17.)

The skeleton-spicules have a straight or curved shaft, which may
be either smooth or notched, and with projecting tubercles, and the
extremities are inflated, or notched, or with small processes. They
are loosely interlocked together at the ends, and form open ana-
stomosing fibres (Pl. XXII. figs. la—-1/). The spicules range from
0-2 mm. to 0'4 mm. in length and about 0:03 mm. in thickness.
There are also irregularly distributed, in certain parts of the sponge,

Vol. 52.] FROM THE CARBONIFEROUS LIMESTONE. 439

a few much larger, simple, fusiform spicules, 0°8 mm. in length.
No dermal layer has been preserved.

In outward aspect this sponge looks like a flattened waterworn
nodule of a greyish tint and a slightly roughened surface, and its
organic character was not fully apparent until sections had been
made through it. The interior is solid, compact, and consists mainly
of chalcedonic silica. The spicules have, for the most part, been
replaced by calcite, but they still retain their details of form very
perfectly. The fibres of the sponge, examined under the micro-
scope, both in vertical and in transverse sections, have a very irregular
and indefinite appearance, and in some places the spicules are
loosely massed together, and scarcely show any definite arrange-
ment, The fibres, where best preserved, are crowded with spicules,
some parallel with the direction of the fibre, others transverse to its
course and projecting into the spaces between the fibres, which are
very seldom free from spicules. The spicules are usually so crowded
and intermingled together that it is difficult to distinguish indi-
vidual forms; but, though there is considerable variation, the main
type has a straight or curved shaft, with notched or digitate ex-
tremities. The spicules appear to be but very lightly connected
together; sometimes their shafts are closely apposed, at others
they are attached by the interlocking of their short terminal pro-
cesses or by the knobs at the end of one spicule fitting into the
notched ends of a proximate one. No axial canals could be seen in
the ordinary spicules of the fibres, but in some of the larger fusiform
spicules they have been preserved. These latter spicules appear in
small bundles of two or three together in the interspaces of the
fibres. A single cylindrical spicule was also met with in the sponge,
but it is probably adventitious.

The genus Pemmatites, to which this sponge belongs, was estab-
lished by E. von Dunikowski ‘ for some compressed discoidal sponges
from the Permo-Carboniferous strata of Spitzbergen, which were
considered by this author to be monactinellid in character, from
the presence of simple fusiform spicules within the sponge. These,
however, proved to be in the interspaces of the fibres of the sponge,
while the fibres themselves were described by E. yon Dunikowski as
the canals. An examination of the type-specimens showed that
the spicules of the fibres had been almost entirely obliterated, but
a few remained, and these proved that the fibres were originally
composed of lithistid spicules.» The discovery of the present speci-
men, in which the fibre-spicules are numerous and well preserved
and lithistid in character, and, moreover, are accompanied by some
fusiform spicules in the interspaces, fully confirms the lithistid
nature of the genus Pemmauatites.

The present species comes nearest to P. latituba, Dun.,*® in the
form of the spicules, but the fibres are much more closely arranged.

1 * Ueber Permo-Carbon-Schwimme von Spitzbergen,’ K. svenska Vetensk.-
Akad. Handl. vol. xxi. (1884) no. 1, pp. 1-18 & pls. i—ii.

2 Geol. Mag. 1888, p. 246.

3 Op. cit. p. 16, pl. i. figs. 2 & 12; also Geol. Mag. 1888, p. 249, pl. viii. fig. 7.

Q.J.G.8. No. 207. 2Q4

440 DR. G. J. HINDE ON NEW FOSSILS [ Aug. 1896,

I propose to name it P. constipatus, from the crowded disposition of
the spicules in the fibres. The only specimen as yet found was
collected many years since by Mr. John Rhodes from calcareous
shale under Woodocrinus-limestone (Yoredale Series) a Thringle
Scar, north of Gill Wood, above the Main Limestone, } mile north
of Throstle Gill and 6 miles north-west of Richmond, Yorkshire.
I desire to express my thanks to Mr. Rhodes for the opportunity
of describing this interesting form.!

IT. On PaLmacis HUMILIS, SP. NOV., A NEW PERFORATE CoRAL, WITH
Remarks on THE Genus. (PI. XXIII. figs. 1-18.)

From the Carboniferous Limestone and shales exposed on the
banks of the River Hodder, near Stonyhurst College, Lancashire,
the Rev. G. C. H. Pollen, 8.J., F.G.S., obtained a series of trilobites
and other fossils, including some small bodies which he supposed to
belong to the genus Palwocoryne, Duncan. At the request of
Dr. H. Woodward,? who described the trilobites from these rocks, I
undertook an examination of these peculiar bodies. Though it
was apparent that they did not belong to Paleocoryne, I could not
at first recognize their relationship to any other organism, and it
was not until after repeated study at different intervals that it
occurred to me to compare them with specimens of Palwacis cunei-
formis® (Haime), M.-Edw., which I had myself collected many
years previously from the Lower Carboniferous rocks of Spergen
Hill, Indiana. It could then be seen that, though differing con-
siderably in general form, they were so far structurally similar that
they could be included in the same genus.

In the meantime some other small dubious fossils from the soft
shales of the Lower Culm Measures at Codden Hill, near Barn-
staple, came under my notice, which, like those from the Hodder,
differed from anything I had previously met with. Unlike these
latter, however, they were only in the form of casts, and conse-
quently less easily recognizable. <A close study of these brought
to light the curious fact that not only do they belong to the genus
Paleacis, but even to the same species as the Hodder specimens.
Though only casts, they serve to illustrate the structure of the
species, and supplement the evidence derivable from the specimens
which have their walls preserved.

The specimens from the banks of the Hodder are nearly all in a
soft shale or mudstone, and in breaking up the rock the under
surface of the fossil, in the form of a St. George’s cross, is almost
invariably exposed (Pl. XXIII. fig. 1), while the upper surface, with
the apertures of the corallites, is covered by the matrix, and can, as
a rule, be seen only by grinding down the rock or removing it with
a needle (Pl. XXIII. figs. 2&3). The walls retain their original
structure of carbonate of lime, but the interior of the calices and

1 [Since this paper was read the specimen has been placed in the Museum
of Practical Geology, Jermyn Street. |

2 Geol. Mag. 1894, p. 481.
3 Hist. Nat. Corall. vol. iii. (1860) p. 171, Atlas, pl. = 1. fig, 3.

Vole 52.) FROM THE CARBONIFEROUS LIMESTONE, 441

the mural pores are frequently in part filled with iron pyrites, and,
as the walls are thin and delicate, the preparation of thin sections
is rendered difficult.

Specific Characters.—Corallum small, quite free and without any
trace of attachment. In its fullest development it consists of four
depressed corallites, starting, on the same plane, from a common
centre, nearly at right angles to each other; in some specimens
only three corallites are present, in others two; while simple forms
of but a single corallite are also not uncommon. In the larger
forms with four corallites (Pl. XXIII. figs. 1, 2, 3 & 4) the central
portion of the base is flattened, and the corallites extend from it at
first in a nearly horizontal direction, and then they gradually curve
upwards and outwards, so that their apertures are somewhat oblique.
The free portions of the corallites are subcylindrical, in section
varying from circular to elliptical. The corallites are not always
of the same length; usually the two forming the transverse axis are
subequal and shorter than those of the longitudinal axis, and in this
axis one corallite is, as a rule, markedly longer than the other
(Pl. XXIII. figs. 3 & 4). The outer surface of the corallum is marked
by distinct ridges, with sharp continuous edges, which, in the distal
or free portions of the corallites, are longitudinal, straight, or slightly
wavy, and subparallel, but in the central portions of the corallum,
‘both on the basal and upper surfaces, they are usually broken up
‘into short, discontinuous, somewhat labyrinthine patterns. In the
longitudinal furrows between the surface-ridges there are rows of
-subcircular mural pores, disposed in alternating series, which pene-
‘trate the wall direct and open into the visceral chamber of the
corallites. These mural pores are not limited to the free lateral
portions of the corallites, but they are present in the basal portions
-as well, some connecting the visceral chambers of adjacent corallites,
while others communicate with the exterior (Pl. XXIII. figs. 6, 9 &
10). The mural pores are but seldom exposed to view on the outer
‘surface of the coral, unless when it is weathered or rubbed down.

The calice, or the interior of the corallite, is conical or turbinate
in form; the inner surface of the wall shows the rows of mural
pores, and the spaces between these are nearly smooth or marked
by slightly impressed lines, but there are no indications of granu-
lations, tubercles, or septa, to correspond with the ridges of the
exterior surface (Pl. XXITI. fig. 12). The apertural margins of the
corallites are thin and slightly crenulate from the projection of the
edges of the wall-ridges.

In the specimens which consist of only two corallites, these are
joined end to end, so that, viewed laterally, the forms appear as
short, nearly cylindrical, curved pipes, with a circular aperture at
each end (Pl. XXIII. figs.5 & 6). The internal form of these coral-
lites is well shown in the casts from the Lower Culm (fig. 6). From
the central portion of these twin forms of corallum one or two
additional corallites are occasionally developed, but in several ex-
amples there are no traces of any lateral buds, and the corallum
appears to have permanently remained a twin form. In the simple

2H 2

442 _ DR. G. J. HINDE ON NEW FOSSILS [ Aug. 1896,

examples of the species the corallum has somewhat the form of a.

rifle-bullet : its basal end is conical and evenly rounded, with no trace.

of attachment ; the outer surface has longitudinal ridges, the same
as in the compound forms; and the wall, both of the sides and base,
is similarly traversed by direct mural pores (Pl. XXIII. figs. 7&8).
The calice is more directly conical than the outer form, so that the
basal portion of the wall is thicker than the upper part, and the
mural pores opening on the exterior through this thickened base

have somewhat the character of canals (Pl. XXIII. fig. 10). In no

example yet discovered are there more than four corallites present.
The microscopic structure of the wall of this species is of radiating

crystalline fibres, like that of corals generally (Pl. XXIII. fig. 15),

and in its present condition of preservation it is closely similar in
appearance under the microscope to a thin section of Favosites, sp.,
from the Devonian, with which I have compared it. The mural.
pores also are comparable with those of Favosites and Plewrodictyum.

Neither epitheca nor coenenchyma is present, and there is no indi-
cation of tabule or of solid non-perforate tissues filling the base of.

the calices.

The diameter of the normal corallum with four corallites ranges:

from 10 to 15 mm.; in length the individual corallites vary:
between 4 and 6 mm., and in width, at their summits, between 3
and 4:5 mm. There are from 20 to 30 longitudinal ridges, and a
corresponding number of rows of mural pores, in a corallite.

The present species, which I propose to name P. humilis, is dis-
tinguished from P. cunetformis, Haime, the typical species, in its
general form and the size and disposition of the corallites; the
external ridges, moreover, are of a coarser character, and they are

more regularly arranged. ‘The resemblance to P. (Sphenopotertum):
obtusa, Meek & Worthen, sp.,' is less apparent, for this latter form.

is considerably larger, its walls are relatively very thick, and the
corallites are wide and openly conical. Palcacis (Sphenopotertum)
enormis, Meek & Worthen,” and its variety depressa, more nearly
correspond in size with the present species, but the surface-strize
are said to be broken up into irregular granules. Owing to the
brief description of this form, no nearer comparison is possible.
For reasons given below, I consider that P. humihs has no generic
relations with (Paleacis) Hydnopora? cyclostoma, Phillips.*

Distribution.—Fairly common in shale or mudstone associated
with limestones and chert exposed in the banks of the River Hodder,
below Stonyhurst College, Lancashire. According to Mr. R. H.
Tiddeman,* the rocks belong to the Southern or Bowland type of the
Carboniferous Limestone of Lancashire, and come in between the
Clitheroe Limestones and the Pendleside Limestones. Collected by
the Rev. G. C. H. Pollen.

Also in soft decayed shale of the Lower Culm Monsen at Overton.

* Proc. Acad. Nat. Sci. Philad., Oct. 1860, p. 447.

* Geol. Surv. Ilinois, vol. ii. (1866) pl. xiv. figs. 1 & 2.

3 “Geol. Yorkshire,’ vol. ii. (1836) p. 202, pl. ii. figs. 9 & 10.
4 Geol. Mag. 1894, p. 482.

‘Vol. 52.] FROM THE CARBONIFEROUS LIMESTONE. 443

Quarry and at Hannaford Quarry, near Barnstaple, North Devon.
Only casts are here found ; they are associated with casts of radio-
daria, trilobites, etc.

Remarks on the Genus Paleacis (Haime), Milne-Edwards.

Various and conflicting opinions have been advanced as to the
¢eharacters and systematic position of this genus. It has been
placed alternately with corals and sponges, and, though latterly it
has been generally regarded as a perforate coral, its real characters
have not yet been definitely settled. This uncertainty appears to
me to be in part due to the fact that some authors have placed in
‘the genus certain forms which widely differ from the typical species,
and have then defined its characters more from these foreign forms
than from the original types.

As is well known, Milne-Edwards! founded the genus on some
small wedge-shaped specimens from the Subcarboniferous Limestone
of Spergen Hill, Indiana, which are described as having the polypary
free, with a finely vermiculate ccenenchyma. The calices were stated
to be divided by two large septa, and also furnished with thirty to
‘forty fine striz, supposed to represent septa which had been de-
stroyed. The author was not positive as to the coral-nature of
these bodies, but he provisionally placed the genus with the Madre-
poride and named the type-species Paleacis cunciformis. It may
here be remarked that later observations have shown that the author
-was mistaken, both with respect to the vermicular coenenchyma
and the two large septa in this species; but, as he gave fairly good
figures of the forms described, no doubt has remained as to their
‘Identity.

The same species, with others allied to it, were independently
described nearly at the same time by Meek and Worthen” under the
generic term Sphenopoterium. They were considered to be corals
allied to Cyathoseris, M.-E. & H.; but a few years afterwards these
same authors,’ relying on the authority of Prof. Verrill, removed
the genus from corals and placed it with sponges. It is now
acknowledged that Sphenopoterium is a synonym of Paleacis, and
priority has been generally conceded to this latter.

In 1866 K. von Seebach‘ referred the genus to perforate corals
and proposed two new species, which have since been regarded as
synonyms of Palwacis obtusa, Meek & Worthen, sp. This author
does not appear to have examined any examples of the type-species
or microscopie sections of the forms described, but states that there
was a vermiculate perforate coenenchyma, in which the individual
calices were enclosed, and he agrees with Milne-Edwards in assigning
‘the genus to the Madreporide.

+ Hist. Nat. Corall vol. iii. (1860) p. 171, Atlas, pl. o 1. fig. 3.
‘? Proc. Acad. Nat, Sci. Philad. 1860, p. 447.
° Geol. Surv. Illineis, vol. ii. (1866) p. 145.
* Nachr. k. Gesellsch. Wiss. zu Gottingen, 1866, p. 241; also Zeitschr. deutsch.
egeol. Gesellsch. vol. xviii. (1866) p. 304.

444 DR. G. J. HINDE ON NEW FOSSILS [Aug. 1896,

Dr. Kunth! next undertook a description of the genus, but he
professedly based his observations on Ptychochartocyathus laxus,*
Ludwig, a coral which he considered to be congeneric with Paleacis ;.
the form that he describes and figures, however, is by no means.
similar to that placed under this name by Ludwig, but appears rather
to belong to Hydnopora(?) cyclostoma, Phillips,” first described by
Phillips from the Carboniferous Limestone of Yorkshire.

Prof. de Koninck‘ followed nearly in the same path as Kunth,
by accepting Hydnopora (?) cyclostoma, Phill., as a genuine Paleacis,
and then relying on its characters for the definition of the genus..
Prof. Ferd. Roemer,’ on the other hand, maintained that H.(?) cy-
clostoma was not congeneric with Paleacis, mainly on the ground.
that it was an attached and not a free form, but subsequently ° he
retained it in the genus, though still regarding it as probably:
distinct.

In 1878 Messrs. Etheridge and Nicholson’ published an excel-
lent paper, ‘On the Genus Palwacis and the Species occurring in.
British Carboniferous Rocks,’ in which, for the first time, reference
is made to the microscopic structure of the various forms. These
authors, however, agreed with De Koninck that H. (?) cyclostoma,.
Phill., really belonged to the genus, and as a consequence the
characters of this particular form, which is very fully described.
and illustrated, largely enter into their definition of the genus.
They reach no final decision as to the systematic position of Paleacis,.
though they consider it more closely allied to sponges than to corals.
Since then, however, Prof. Nicholson ® has fully acknowledged that
Paleacis is a perforate coral, but it should be remembered that
this conclusion refers rather to Hydnopora (?) cyclostoma, Phill.,
than to the type-species of the genus.

In order to determine the question as to the rightful characters.
of Paleacis and whether Hydnopora (?) cyclostoma, Phill., can pro-
perly be incorporated in this genus, it will be necessary to consider
separately the main features of P. cunetformis, M.-Kdw., the un-
doubted type of the genus, and of H.(?) cyclostoma, Phill., and.
then compare them together.

Taking first P. cunetformis, a difficulty is experienced at the
outset owing to the rarity of examples of this species and their
unfavourable condition of preservation. JI have had mainly to
rely upon a few specimens, obtained from the same beds at Spergen
Hill as those that yielded the type-forms, with which they correspond
very closely. They are, however, siliceous and replaced in part by
beekite, so that their microscopic characters are obscured. The

1 Zeitschr. deutsch. geol. Gesellsch. vol. xxi. (1869) p. 183.

5 Bee peatepiicn, vol. xiv. (1866) pp. 189, 231, pl. xlvii. fig. 14, pl. Ixix..
fig. 2a.
3 ‘Geol. Yorkshire,’ vol. ii. (1836) p. 202, pl. ii. figs. 9 & 10.

4 “Nouv. Recherches Anim. foss. Terr. Carb. Belgique, 1872, pt. i,
pp- 154-161. .

° ‘Lethzea Paleozoica,’ Atlas, 1876, pl. xxxix. Explanation.

§ Ibid. Text, 1880, p. 515.

7 Ann. & Mag. Nat. Hist. ser. 5, vol. i. (1878) pp. 206-227, pl. xii,

5 “Man. of Paleontology,’ 3rd ed. vol. i. p. 310,

Vols 52.] FROM THE CARBONIFEROUS LIMESTONE. 445

specimens discovered by Mr. Spencer G. Perceval’ from the Lower
Limestone Shales of Combe Down, Henbury, near Bristol, have
lately been acquired by the British Museum (Nat. Hist.), but they
are also partially silicified and do not show the structure so clearly
as the American examples. The colony is small, wedge-shaped,
with a compressed base which is quite free; there are from two to
four corallites arranged in a single lateral series. (Pl. XXIII.
figs. 16 & 16a.) In some cases the upper margins of the corallites
project beyond the general surface, and are free, sharp-edged, and
minutely crenulate. The outer surface of the corallum has longi-
tudinal, subparallel, slightly wavy ridges, and in the furrows between
these are rows of mural pores, which extend directly through the
wall and open into the interior of the calices. The calices are
conical, varying from nearly circular to oval or elliptical in section ;
within they show the rows of pores, and between these are faintly-
marked ridges or lines, which may represent septa. Pores or canals
also pass between and connect the corallites. The wall in the
compressed basal portion of the corallum is now, in the specimens
examined, solidly replaced by silica, and its original structure
doubtful, but there are no indications of a vermiculate coenenchyma,
and it may have been perforated by simple pores or straight canals,
like those in the upper portion of the corallum, which, moreover,
closely resemble those already described in P. humilis.

Turning now to Hydnopora (?) cyclostoma, Phill., of which
examples are fairly common in the Carboniferous Limestone of
Northumberland, and of Fifeshire and other places in Scotland,
we find it growing in small colonies usually of from two to six
corallites, but in some cases twelve have been observed. The
corallum is invariably attached to some foreign body, and its basal
portion in part conforms to the figure of the shell or other organism
to which it is affixed, and in part is free and covered with con-
centric wrinkles or ridges. The calices are open, with nearly
straight sides; their margins may be either free or on a level with
adjoining calices; and the interiors are furnished with numerous
tubercles or blunt spines, which are crowded over the bottom of the
cup and disposed regularly in rows on the sides, where they appa-
rently represent the septa. The outer surface of the coral has
interrupted sinuous ridges and granules, with, in places, irregular
apertures between. ‘The structure of the wall, as shown in sections,
is of a remarkable character. The basal portion or floor within
each calice, and the sides as well, nearly if not quite up to the
margin, consists of a layer of solid, non-perforate, calcareous tissue,
outside of which, occupying the space between the calices and also
forming the basal layer of the corallum, there is a well-marked
layer of an openly porous or lacunar reticulate tissue, strikingly
similar to that of recent perforate corals. ‘This layer, which may
be considered as a porous coenenchyma, has been very carefully
described and figured by Etheridge and Nicholson.”

The minute structure in . (?) cyclostoma is of radiate crystalline

' Geol. Mag. 1876, p. 267.
? Ann. & Mag. Nat. Hist. ser. 5, vol. i. (1878) p. 215, pl. xii. figs.7 & 8.

446 DR. G. J. HINDE ON NEW FOSSILS [Aug. 1896,

fibres precisely similar to that in recent corals. Though in reality
compact, under certain conditions of preservation, microscopic sec-
tions of it give the erroneous impression of being traversed by
minute tubuli.

It will be seen on comparing these two forms, Paleacis cunet-
formis, M.-Edw., and Hydnopora (?) cyclostoma, Phill., that the
differences between them are of too radical a character to allow of
their inclusion in the same genus. In the former the walls are
simply perforated by mural pores or canals analogous to those in
Paleozoic Favosite corals, while in the latter there is a distinct
lacunar coenenchyma, similar to that in modern perforate corals,
and moreover the interior of the calices has a solid non-perforate
layer which carries the blunt septal spines or tubercles. Minor
differences are the wrinkled outer surface and the attached mode >
of growth in H. (?) cyclostoma.

Of the other species referred to Palwacis, that herein described
as P. humilis approaches nearest the type-species.1 P. obtusa,
Meek & Worthen, sp. (=P. cymba? and P. uwmbonata,* Von
Seebach), P. compressa,* M. & W., sp., and P. enormis, M. & W.,sp.,
form a group markedly distinct from the type-species of the genus
and P. humilis in the larger size of the corallum, the openly conical
and shallow form of the calices and the much greater thickness of
their walls. As regards the structure of the walls in these forms
nothing definite is as yet known. In the specimens of P. obtusa
from Spergen Hill, Indiana, belonging to the British Museum
(Natural History), which I have examined, the interior is now a
solid mass of silica and all traces of pores or canals have been
obliterated, and it therefore remains an open question whether they
were similar to P. cuneiformis in this feature or not. The principal
grounds for including them under Paleacis, M.-Edw., are their
general form, striated or ridged outer surface, and free condition
of growth.

(Since this paper was read Mr. E. T. Newton, F.R.8., has brought to
my notice a specimen of Palwacis obtusa, Meek & Worthen, sp., from
the Carboniferous Limestone of Hook Point, Wexford, Ireland, now
in the Jermyn Street Museum, in which the structure has not been
altered by silicification, so that the character of the wall in this
species can be determined. The specimen in question (Pl. XXIII.
fig. 18) is partially weathered out on the surface of a piece of lime-
stone; it is wedge-shaped, free, about 13 mm. in width, and nearly
the same in height. There aresix shallow, openly conical corallites
at the summit. The outer surface is covered with fine, somewhat -
wavy striz or ridges, which have a general direction towards the
centre of the base ; in places they are discontinuous and interrupted.
A vertical median section shows that the corallite-walls are regu-
larly perforated by pores and canals, which connect adjoining
ecalices and also pass through to the exterior (Pl. XXIII. fig. 18 a).

1 Geol. Surv. Illinois, vol. ii. (1866) p. 233, pl. xvii. figs. 2 a-e.
2 Zeitschr. deutsch. geol. Gesellsch. vol. xviii. (1866) p. 309, pl. iv. figs. 4a & 6.
3 Ibid. figs. 3a & 6. 4 Op. jam cit. p. 284, pl. xvii. figs. 1 ae.

Vol. 52.] FROM THE CARBONIFEROUS LIMESTONE. 447

‘They are present in the basal as well as in the lateral and marginal
portions of the corallum, and they closely correspond to those in
P. cuneiformis and P. humilis. There are no indications of a porous
or lacunar ceenenchyma. This specimen is smaller and the surface-
ridges are somewhat finer than in the Indiana examples of the
species. De Koninck* has already recorded the occurrence of this
form in the beds at Hook Point.—May 18th, 1896. ]

The genus Puleacis, accepting P. cuneiformis, M.-Edw., as the type,
appears to represent a distinct family of perforate corals in some
features more nearly allied to the Favositide than to the Madre-
poride or Poritide. Thus, for example, with respect to the per-
foration both of the bases as well as the sides of the corallites by
mural pores and canals, we find a similar condition of things in
Pleurodictyum granuliferum, Schliiter,? from the Middle Devonian
ef the Hifel, and this moreover is quite a free form.

By the removal of Hydnopora(?) cyclostoma, Phill., from Palwacis
this form must represent an independent genus for which I venture
to propose the name of Microcyathus. Ferd. Roemer’ considered
that it might be included under Ptychochartocyathus, Ludwig,* but
if any reliance is to be placed on the description and figures of the
type of this genus, P. lawus, Ludwig, there is certainly no generic
relation to Hydnopora (?) cyclostoma, Phill. Ludwig states posi-
tively that P. lawus has thick non-perforate walls, no mention is
made of a lacunate coenenchyma, and, judging from the figure,
there is no resemblance in its mode of growth and the disposition
-of the calices to H. (?) cyclostoma, Phill.

In this connexion it will be desirable to mention another coral,
the Astreopora antiqua, M‘Coy,’ from Hook Point, Wexford, which
thas been regarded as a synonym of H.(?) cyclostoma, Phill. I have
not seen the type-specimen, but examples from the same locality as

‘the type, which correspond with M‘Coy’s figures, are in the Jermyn

Street Museum, and through the kindness of Mr. E. T. Newton,
F.R.S., a section has been prepared from one of these, which I have
examined. The calices are very shallow, and the walls apparently

consist of compact tissue, in which there are some irregular tubes—

as if due to some boring organism. The section was not altogether
lear, but there were no indications of a lacunar intermediate
tissue between the calices as in Microcyathus (Hydnopora?) cyclo-
stoma, and it is evidently generically distinct from this latter.

In conclusion I wish to express the great obligations under which
Tam to the Rey. G. C. H. Pollen, 8.J., F.G.S., for supplying me with
the specimens of Palcacis humilis, and I am glad to state that this
gentleman intends presenting the type-forms to the British Museum
(Natural History).

* *Nouy. Rech. Anim. Foss. Terr. Carb. Belgique,’ pt. i. 1872, p. 158.
* «Anthozoen des rheinischen Mittel-Devon,’ Abhandl. k. preuss. geol. Landes-
anst. 1889, p. 193, pl. iv. figs. 5-8.
° « Letbaa Palzozoica,’ Atlas, 1876, pl. xxxix. Explanation.
Eerie ge > vol. xiv. (1866) pp. 189, 231, pl. xlvii. fig. 14, & pl. lxix.
ig. 2a.
‘Syn. Carb. Limest. Foss, Ireland,’ 1844, p. 191, pl. xxvi. fig. 9.

448 DR. G. J, HINDE ON NEW FOSSILS [Aug. 1896,

III. On rae Jaw-apparatus oF an Annenip (Kunicires Ruipim,
SP. NOV.) FRoM THE Lower CarBonirERovs or Hatxin Movun-
TAIN, FuintsHire, (Pl. XXII. figs. 2, 2a, & 2¢.)

In the numerous examples of the jaw-plates of annelids described
by the writer some years since from the Paleozoic rocks of Canada,”
England,” Scotland,’ and the Isle of Gotland,* without exception the
small constituent plates of the jaw occurred separately on the rock-
surfaces, detached from the relative positions which they occupied
in the living condition of the animal. These small bodies have
subsequently been discovered in the Upper Silurian rocks of New
South Wales by Mr. Robert Etheridge,’ and in the Middle Devonian
of New York State by Dr. J. M. Clarke,° and always in a similarly
detached condition, with the single exception of the jaw-apparatus:
of a species of Arabellites, discovered by Dr. Clarke, in which the
different dentated plates, now somewhat fragmentary, are shown
in the natural position that they occupied in the jaw-sac of the
animal,

I propose now to describe another and more perfect specimen
than that just referred to, in which the upper jaw-plates of a
species of Hunicites have been preserved, showing their natural
position with respect to each other. The specimen in question was.
discovered by Miss Margery A. Reid in some thin black fissile
shales of the Lower Carboniferous formation at Halkin Mountain,
Flintshire. In splitting open a piece of the shale the jaw was-
found standing out in relief on the surface of one piece and the
counterpart on the other. A portion of one of the large pincers
and of one of the dental plates must have been broken away when
the shale was splintered; with these exceptions the jaw-apparatus
differs but little in appearance from that of a recent annelid. It
has precisely the same glossy black aspect as the upper jaws of
recent annelids, and, like these, must have been originally of
chitinous material. )

As now exposed, the jaw-apparatus shows its upper or free
surface. It consists on each side of a support, pincer, and dental
plate; probably paragnaths were also originally present, but only a
single one of these has been found. The entire length of the jaw is
5-4 mm., and its greatest width4-1mm. The supports a (Pl. XXII.
figs. 2 & 2a) are approximately oblong in outline, with a straight
upper margin where they come into contact with the base of the
pincer, nearly straight sides, and rounded ends. The surface has a
slightly elevated ridge, which runs obliquely. They are now about
1-2 mm. inlength by 7 mm.in width. Itis probable that they were
longer than is now shown, judging from an impression on the shale,
which indicates that they were originally prolonged to a blunted.

1 Quart. Journ. Geol. Soc. vol. xxxv. (1879) p. 370.

2 [bid. vol. xxxvi. (1880) p. 368. 3 [bid. vol. xxxv. (1879) p. 386.

4 Bihang till k. svenska Vet.-Akad. Handl. vol. vii. (1882) no. 5.

5 Geol. Mag. 1890, p. 339.

6 Sixth Annual Report of the State (New York) Geologist, for the year 1886.
Albany, 1887.

‘al

Vol. 52.] FROM THE CARBONIFEROUS LIMESTONE. 449

base. The pincers 6 (figs. 2 & 2a) are robust, with straight bases
where resting on the supports; above the base there is a well-
marked curve, terminating in an angle where the pincer is widest :
from this the plate gradually curves upwards and ends in a stout:
hook. There is a rounded ridge along the outer margin of the
pincer, and a distinct nodular elevation at the narrow basal end..
The pincers are 3°8 mm. in length and 1:5 mm. at their greatest
width. The dental plates d (figs. 2 & 2a) are elongate, with a
nearly straight base ; at the anterior end is a stout curved denticle,.
followed by a much smaller one, and then by a series of stout
conical denticles, of which there are nine in the left plate, but only
five are shown in the cast of the right plate, The denticles in the
right plate d (figs. 2 & 2a) as shown in the cast are stronger than.
those of the left (¢c), and though one or two may be concealed I do:
not think there were as many as in the left. The position of these
dental plates in regard to the pincers is remarkable. They now
rest with the curved anterior tooth and the succeeding series of
denticles turned towards the exterior side of the jaw and having:
their straight bases facing each other as shown in fig. 2, whereas:
in recent allied forms these plates have their dentated margins
facing each other, and their straight or curved bases are within or
beneath the curved hollows of the pincers. It is difficult to see:
how in the fossil the dental plates could act conjointly with the
pincers in their present position, and I can only suppose that they
have been turned outward by subsequent pressure. In the
specimen, as shown in fig. 2, the greater portion of the right:
dental plate (d) has broken away, but the cast of it is preserved in
the counterpart, as seen in fig. 2 a, while the left plate (c) is complete,.
with the exception of the anterior hook which is shown in the cast..
The length of this plate is 3°3 mm., and its width at the anterior end
isl-l mm. A cast of a nearly similar but somewhat smaller dental
plate occurs in a detached condition on another slab of shale (fig. 3)..-
I cannot find positively that any unpaired dental plate was present.
in the specimen, though it is possible that it might be hidden
beneath the upper plate (c). Attached near the side of one of the
pincers was a small plate, roughly triangular in outline, with four
blunt denticles on one margin and a small projection from the

.opposite angle, which may possibly have been a paragnath of the:

same specimen, though it is relatively small in comparison with
similar plates in recent forms (Pl. XXII. fig. 2¢). Another minute:
detached plate, which may have been a paragnath, is shown (fig. 4),.
but there are no grounds for connecting it with the larger specimen.
No traces of any structure resembling the lower jaws of an annelid.
corresponding to this upper Jaw-apparatus have been discovered.
Notwithstanding the peculiar position of the dental plates in:
this jaw, the individual pieces correspond with sufficient closeness:
to those of the recent Eunicea family for this to be included in the
genus Hunicites, Ehlers, as a new species, Hunicites Reidiw, im
honour of its discoverer. The only annelid-remains known hitherto
from the Lower Carboniferous are some detached plates from the
shaly limestone of Cults, Fifeshire, and among these is a pincer

450 DR. G. J. HINDE ON NEW FOSSILS [Aug. 1896,

of Hunicites, which is smaller and more slender than that of the
form here described.

The present specimen was discovered in some dark, thin, shaly
beds in the Carboniferous Limestone Series near Bwlch, about
1 mile N.N.E. of Nannerch, Halkin Mountain, Flintshire, and
associated with it in the same beds were fragments of polyzoa and
some trilobites, the latter of which have been determined by
Mr. EK. T. Newton as Phillipsia Hichwaldi, Fischer. The specimen
has been presented by Miss Reid to the Museum of Practical
(Geology, Jermyn Street.

EXPLANATION OF PLATES XXII. & XXIII.
Puate XXII.
Pemmatites constipatus, sp. nov. Figs. 1, 1 a-l1m.

Hig. 1. The sponge showing the upper surface. Natural size.

la,16,1ce. Spicules from the fibres showing their individual forms.
Enlarged 60 diameters.

1d,le,1f,1g,1%. Spicules from the fibres showing their mode of
union. Knlarged 60 diameters.

1%, A portion of a spicular fibre as shown in a horizontal section of the
sponge. Enlarged 60 diameters.

1%. A portion of a spicular fibre as shown in a vertical section of the
sponge. Similarly enlarged.

17. A portion of a spicular fibre with canals, as shown in a horizontal
section. The spicules are too crowded to be individually distin-
guished. Similarly enlarged.

lm. Fusiform spicules (fragmentary) from the interior of the sponge.

Enlarged 60 diameters.
From the Yoredale Series at Thringle Sear, near Richmond, Yorkshire.
«Collected by Mr. John Rhodes, and now in the Museum of Practical Geology,
Jermyn Street.

Eunicites Reidig, sp. nov. Figs. 2, 2a, 2e.

Fig. 2. The jaw-apparatus: (a) The supports. (b) The pincers. (c) ‘The
dental plate of the left side. (d) The corresponding plate of the
right side, imperfect. A portion of the pincer on the left oe is also
missing. Enlarged 10 diameters.

2a, The same as shown in the counterpart, similarly enlarged.
2e. A paragnath, probably belonging to the same jaw. X10.
“3. The cast of a dental plate, detached. X10.

4, A small paragnath, detached. x 10.

5. A fragment of a pincer, detached. X10.

‘The specimens are from the shaly beds in the Carboniferous Limestone Series
‘near Bwlch, about 1 mile N.N.H. of Nannerch, Halkin Mountain, Flintshire;
they are preserved in the Museum of Practical Geology, Jermyn Street. Col-
lected by Miss M. A. Reid.

Pruate XXIII.
Paleacis humilis, sp.nov. Figs, 1-15.

Fig. 1. A complete specimen as it occurs in the rock, showing the basal portion
and the surface-ridges. Enlarged 2 diameters. rom the Carboni-
ferous Limestone, River Hodder, Stonyhurst, Lancashire.

2. The upper surface of a fairly complete specimen with four corallites.
x 2 diameters.

3, 4. The upper and under surfaces of a specimen in which one of the
corallites is much longer than the others. This is entirely free from
the rock-matrix. x2 diameters.

<— ld

fy
a ae |

x10

f A.T.Hollick bth. Mintern Bros. imp.
: PEMMATITES CONSTIPATUS,sp.nov.
‘GAIT Ae Ce SS REID IAL. sp.nov.

eit, a —

Quart Journ. Geol. Soe: Yo! LIL. Pl, AAW.

A.T.Hollick lith. Mintern Bros imp.
AAC IS.

:
{

Vol. 52. | FROM THE CARBONIFEROUS LIMESTONE. 451

Fig. 5.

6.

16,

i

18.

A specimen consisting of only two corallites, viewed laterally. x3 dia-
meters. River Hodder.

The cast of a specimen consisting of only two corallites, showing in:
the one half the solid infilling of the calice with the mural pores, and

- in the other the casts of the outer wall and the longitudinal ridges.
<5 diameters. From decayed shale in the Lower Culm Measures
at Hannaford Quarry near Barnstaple.

. A specimen consisting of but a single corallite, quite free from the

matrix. 5 diameters. River Hodder.

. A cast of another single specimen, showing the thickness of the wall at

the base and the form of the interior of the calice. 5 diameters.
Lower Culm Measures, Hannaford Quarry.

. A horizontal section of a specimen with four corallites, showing the

mural pores between contiguous corallites and those opening to the
exterior. X95 diameters. From the River Hodder.

. A transverse section of a single corallite near the base, showing the

thickness of the wall and the mural pores or canals. X10 diameters.
River Hodder.

. A transverse section of a corallite-wall near the summit. 5 dia--

meters.

. A portion of the inner surface of a calice, showing the mural pores.

< 10 diameters.

. A portion of the under surface of a corallite which has been rubbed:

down, showing the mural pores. 10 diameters. River Hodder.

. Portion of the outer surface, showing the longitudinal ridges. X10

diameters.

. Portion of a translucent microscopic section of the wall showing the

fibro-crystalline structure and one of the mural pores. X75 dia--
meters.

16a. Paleacis cuneiformis, M.-Edw. Front and side view of a speci-
men with four corallites. Natural size. From the Subcarboniferous -
(St. Louis) Group, Spergen Hill, Indiana.

17 a. Paleacis obtusa, Meek & Worthen, sp. Front and side view of a
specimen with five calices. Natural size. From the Subearboniferous
Limestone, Keokuk, Iowa.

The same. Front view of a small specimen with six calices. Natural
size. From the Carboniferous Limestone of Hook Point, Wexford.
The specimen belongs to the Jermyn Street Museum.

18a. The same. A vertical median section of the same specimen, showing’

three corallites, now filled with the rock-matrix and the mural pores,.
and canals traversing the walls. 3 diameters.

Discussion.

Mr. Srrawan remarked on the richness of Halkin Mountain in
fossils, and suggested that it would be advisable to fix more exactly
than seemed to have been done the locality and horizon in the lime-

stone

of the annelid described. He congratulated Miss Reid on the

discovery of this unusually perfect specimen.

Prof. T. Rurzrr Jonzs also spoke.

The AvrHor replied that he would endeavour to obtain more
definite particulars as to the exact horizon of Hunicites, and thanked.
the Fellows for the reception accorded to his paper.

A52 MISS E. ASTON AND PROF, BONNEY ON [Aug. 1896,

22, On an Atpine NickEL-BEARING SERPENTINE, with FULGURITES.
By Miss E. Asron, B.Sc., with PrrrograpuicaL Norns by
T. G. Bonney, D.Sc., LL.D., F.R.S., V.P.G.S., Professor of
Geology and Mineralogy in University College, London. (Read
March 11th, 1896.)

Tue rocky peak of the Riffelhorn (9616 feet), well known to all who
have visited Zermatt and the Gornergrat, forms part of a large
mass of serpentine which secms to vary slightly in composition and
as generally more or less schistose, becoming in places quite slaty —
the effect of pressure." On the summit of this peak the compass,
as is well known, exhibits the most extraordinary variations, and
the rocks appear to be not seldom struck by lightning.” Specimens
exhibiting fulgurites were collected on it by both Prof. W. Ramsay
and Mr. J. Eccles in 1890, the examination of which has led to
some interesting results.

The geologist, in working over different parts of this large mass
of serpentine, observes that, where the original structure is not
obscured by subsequent pressure, the rock is not quite uniform in
eharacter—one variety being an ordinary dark green bastite-serpen-
tine (sometimes also containing augite), the other being a little
tougher and harder under the hammer and slightly rougher when
handled ; in short, it is not quite so normal a serpentine as is the
other variety. Of this harder kind the upper part (at any rate) of
the Riffelhorn peak is composed.

It will be convenient to speak of the microscopic structure and
chemical composition of the rock before describing the effects of
the lightning, though the latter was the reason that induced Prof.
Ramsay to ask the present authors to investigate the former
questions.°

Slices for microscopic examination were prepared from four separate
specimens. These exhibit slight varietal differences, which, how-
ever, are comparatively unimportant. Hence their constituent
minerals may be described together. These are :—

(a) A clear colourless mineral in flakes, which are sometimes rather
irregular in outline and vary in size up to about ‘025inch. They
have a mica-like cleavage, but it is hardly so well defined as
in that mineral. The smaller flakes, with crossed nicols, give
bluish-white and dull blue tints; the larger fairly bright
colours. The majority give straight extinction, but not a few
flakes (which correspond in all other respects) extinguish at

} See, for details, Bonney, Geol. Mag. 1890, p. 533.

2 Tyndall, ‘ Glaciers of the Alps,’ 1860, pp. 141-145.

> Miss Aston is responsible for the chemical work ; Prof. Bonney for that
with the microscope.

Vol. 52.] NICKEL-BEARING SERPENTINE. 453

small angles up to about 10°.1. The mineral (if it is a single
one) in some respects resembles antigorite, but that is detined as
slightly green in colour, with one very well-marked cleavage,
a slight dichroism and straight extinction.” That this is one
of the group of minute minerals included under the name
serpentine cannot, we think, be doubted, and one of us has
frequently met with both the above-mentioned varieties in
Alpine serpentinous rocks which have been subjected to great
mechanical disturbance.

{b) A clear colourless mineral in granules, grains, and rather rude
prismatic shapes, sometimes occurring in groups as if they
were remnants of larger crystals; where these are of sufficient
size and regularity for measurement, the mineral proves to be
an augite and some of the grains retain traces of a cleavage,
indicative of diallage.

{c) Here and there we find grains with an orange-yellow tint,
which, however, we believe, are only the same mineral stained,
probably with an iron oxide.

({d) Opaque black granules or grains, without definite shape, often
more or less clustered. Examination with reflected light
shows most of them to be an iron oxide, generally magnetite,
but it indicates the occasional presence of a mineral, somewhat
intermediate in colour between pyrite and native copper. One
of us possesses,—owing to the kindness of Prof. Ulrich—
a small quantity of the awaruite found in river-sands on
the west coast of the South Island, New Zealand, and de-
scribed by him’; and after a careful study of the two he
ventures to pronounce this also to be awaruite.

The mode in which the above minerals are associated and the
structure exhibited in the slices indicate beyond question that the
rock has been greatly crushed, somewhat sheared, and occasionally
much crumpled. Their relations one to another make it highly
probable that some of the serpentinous mineral (antigorite?) has
replaced augite,* but in other cases this constituent suggests an
independent origin, and in one it occurs in association with the
iron oxide, as in an ophitic structure. The reconsolidation of the
rock since the epoch when the crushing took place seems to have
been practically complete, the only macroscopic effect being a very
slight schistosity. This, however, does not hold good in every part

* I find these chiefly among the larger, brighter-coloured flakes. It is
possible that a small flaky hornblende may occur in the rock, but I cannot
ascertain more than that some flakes extinguish at small angles.—T. G. B.

? Teall, ‘ British Petrography,’ 1888, p. 113.

* Quart, Journ. Geol. Soc. vol. xlvi. (1890) p. 619. This mineral has also
been described from Scandinavia and Saxony.

* My work among Alpine serpentines leads me to the conclusion (which I
hope before long to set forth more fully) that the so-called ‘antigorite’ is more

indicative of the action of severe pressure than of the former presence of
augite.—T. G. B.

454 MISS E. ASTON AND PROF. BONNEY ON [Aug. 1896,.

of the Riffelhorn, for there is some very fissile serpentine near the-.
base of the peak on the more northern side.’

It may be interesting to note that the huge boulders near the
Mattmark See, in the other branch of the Vispthal, appear to
belong to the same variety of serpentine. A slice cut from a specimen
collected by one of us from the smallest of the boulders agrees-
very closely with those described above, and it, too, contains a
little awaruite.

Proceeding now to the chemical composition of the Riffelhorn
rock, we come to two specimens, generally similar under the micro-
scope, but in the one perhaps there was rather more of the bright-
coloured flaky mineral than in the other, while in it awaruite was:
distinctly present, and a little of the pyroxene exhibited a faint
brown pleochroism.

These specimens proved on analysis extremely interesting, on.
account of the low percentage of water compared with the amount
of silica and magnesia, the practical absence of lime—of which only
a trace could be detected,—and the presence of a considerable
quantity of nickel: traces of copper and arsenic were also found.
On first analysing the rock (from the first-named specimen), the
nickel was not precipitated, but the total, as will be seen below, only
added up to a little over 95 per cent.

A. B.
SiO ret: ebb n cas oe 40°10 40°61
ALO;
FeO, Ra et 8°82 8°66
FeO
MEO is eect 41°12 41:04
CaO: Ga eee oe trace trace
Combined water... 490 4°67
IM orsturodcieedeeaee 0:24 0:24
95:18 95:22

An analysis was then made of a considerable quantity of the
rock from the second specimen, 5 grams being taken instead of
the usual 1 gram. The copper and arsenic were precipitated
with sulphuretted hydrogen in acid solution; the mixed sulphides
were boiled with nitric acid, and then the copper was precipitated as
oxide by means of soda. The arsenic was re-precipitated as sulphide,
and collected on a weighed filter. Both the copper and arsenic
were present in quantities so small that great accuracy in their
determination was not possible. The nickel was precipitated with
soda: it was weighed as oxide of nickel. Lime was most carefully
tested for with ammonium oxalate, but only a slight turbidity
appeared after long standing.

The analysis was as follows :—

1 See the description in Geol. Mag. 1890, p. 533.

Vol. 52.] NICKEL-BEARING SERPENTINE. 455

Py) Seay aa et rds ees 41°81
Pie, 0-68
Ee arte hcacens ovasastscacess 0713
ner, taon, wuneessecserar catecn 5°59
(oO) 0 can kegs ie I et de ae eR 1°42
OLE OS BRR one Dea Reta hd See 0°15
CD oN RO EE eee 4°92
GELS ee gd MAR ae heer BO trace
ECO SR Sp Sa ps he ah 39°86
Combined water ..............- 4:90
Mioistureyits <c.tottesctceetste ta. 0°04
99°46

The chemical analysis of the rock indicates that quite half the
minerals must be anhydrous, so one at least of these—olivine,
enstatite, augite, or hornblende—ought to be present. There is a
group of augites and hornblendes in which the amount of lime is
very small, but they generally are either altered and contain a
large percentage of water, or are rich in iron and soda. The amount
of iron found in this rock is, however, not much more than sufficient
for the magnetite and awaruite. Anthophyllite is rich in magnesia
with some ferrous oxide, but is rhombic, and most, if not all, of
the pyroxenic mineral in this rock is monoclinic. But the analysis
shows almost 5°/, of nickel oxide, while the awaruite observed
would not require so much as 1°/,. Thus the nickel oxide must be
largely present in one of the transparent minerals, and, since lime
is only present as a trace, we infer that the anhydrous mineral is a
variety of pyroxene in which lime has been replaced by oxide of
nickel."

In the hope of obtaining further proof, the rock was coarsely
ground up in a mortar, and an attempt made to separate the light-
coloured fragments from the darker. To obtain the former clean
was comparatively easy, but the dark were generally encrusted with
the lighter. The specific gravity was determined: that of the rock
itself was 2°71; of the light fragments 2°68, and of the dark 3°17
(lower than one would expect, owing to their not being clean). The
light portion of the rock was analysed and found to contain nickel,
which again points to the presence of nickel in the pyroxenic mineral.

A third specimen was examined which also had been obtained
from the summit of the Riffelhorn, at a short distance from the
other two. Under the microscope it was rather less augitic than
the last named, but that mineral certainly was present, though no
lime (after using the test described above) was found’; nickel also
was sought for and was not found, As the slice shows a grain or
two of awaruite, this metal is probably present only sporadically,
and not as a constituent of the pyroxene.

* (Mr, F. Rutley, since this paper was read, has kindly called my attention
to a description of hydrous nickel silicates (garnierite and noumeaite) by Prof.
Liversedge (Journ. & Proc. Roy. Soc. N.S.W. vol. xiv. 1880, pp. 231 e¢ seqq.).
Analyses of these and of nickel-magnesia silicates are given by Dana (‘System
of Mineralogy,’ 6th ed. 1892, pp. 676, 677, 686), but all seem to differ from the

above in important respects.—T. G. B.]
? The absence (virtual) of lime was confirmed by an independent analysis.

Q.J3.G.8. No, 207. 25

456 MISS E, ASTON AND PROF. BONNEY ON [ Aug. 1896,

Two analyses were made, but both came out a little too high :—

A. B.
SIO), ss cawisn aeameeeeneetes 40:27 40°25
AdZO).. scare eee 3°96 3°26
HeiQ) co casseccrecneccee: 2:22, 2:95
HeOy cee. 2°69 2°69
MeO. uiie eee aerene 41°69 41:01
INasQ desc cneeeseeeic saa’ O71 0-71
Combined water ...... 9°46 9:56
M@iSture’ Use. ccceccce ss. 0:17 0-17

101°17 100°60

This is nearer to the analysis of an ordinary serpentine, but the
amount of alumina is rather large; possibly a colourless chlorite
may be present among the flaky minerals, as described in the
Rauenthal serpentine.’

In conclusion, a lightning-struck rock may be noticed which was
obtained by Prof. Ramsay on the Hornli (9492 feet), a well-known
point of view near the base of the Matterhorn. Itis a somewhat
prismatic fragment, measuring about 12 x13%x17 inches. Macro-
scopic examination shows that it is a variety of the ‘ griner
schiefer’ or ‘green schist’ of the Zermatt district, very familiar to
one of us.”

As there is nothing unusual in its aspect, and the lightning-marks
would be easily damaged, we have not had a slice prepared. The
green mineral in this group of rocks is sometimes chlorite, some-
times a more or less actinolitic hornblende ; felspar or some kindred
aluminous silicate, epidote, garnet, are often—and glaucophane is
occasionally—present.

On analysis a fragment of this specimen gave the following
results :—

A. B.
SIO} snicddancmeneoopeeeates 42-80 43-09
ALO, * secersccesenerenee 18°53 17-15
HejO, .csidostemseneee 7-79 7°85
BeQ ' is.) ner 5:01 5:93
CaO’ 0.22 eee 11°74 12:05
MeO. ..c..sheekamucemene: 8:96 9:04
CuO? 2 cccdttocee eres trace trace
WNa.O: .2c2c2h eee eee trace trace
Combined water ...... 4°71 5:10
Moisture: si.nscaeen et 0:17 018

1 Wadsworth (‘Lithological Studies,’ pp. xxiv-xxviii) quotes 15 analyses of
serpentine from nine different localities in the Alps, six of them representing
specimens from the Zermatt district. In these analyses the SiO, varies from
39°7 to 42°8, the MgO from 30:1 to 41°3, and the H,O from 9-3 to 13°.
Alumina, lime, and nickel are often wanting: the maximum of the first being
2:8, of the second 4°7, of the third 0°5. Other analyses, with two of antigorite,
are quoted by Teall in his interesting chapter on serpentine (‘ British Petro
graphy,’ pp. 113, 114).—T. G. B. .

2 Bonney, Quart. Journ. Geol. Soe. vol. xlix. (1893) p. 94.

ial. 52%] NICKEL-BEARING SERPENTINE. 457

We proceed next to describe the effect of the lightning. Of the
specimens before us the first was collected and given to the Museum
at University College by Mr. Eccles. It is a rude slab measuring
about 94 x 53 x 1 inches, from which a large flake (also brought) has
been split off, exposing a sinuous clear-drilled tube (in outline not
unlike some photographs of a lightning-flash), measuring about
4 inches from end to end and terminated by outer surfaces of the
fragments. It throws off a short curved side-branch, and its
diameter is rather variable, but generally not more than |, inch.
The tube is lined with a film, hardly so thick as stout note-paper,
which exhibits a minutely pitted surface. This film in the inner
part of the tube is brown in colour, but it becomes black on or near
the outer surfaces. Underneath it the walls of the tube appear to
be quite smooth. Apertures or portions of two or three similar
tubes occur on the other side of the slab.

The next specimen (represented by the second analysis, p. 455)
is rudely quadrangular, measuring about 4x3x17 inches. On
both sides short tubes are seen here and there, measuring about
z= inch in diameter or sometimes rather less, which branch and
occasionally enter the rock without, however, piercing through it.
Similar wavy and branching tubes are exposed on one of the sides,
which is fractured. The minor features of these tubes, so far as can
be seen, are identical with the last described.

A third specimen (represented by the first analysis, p. 454) is
a rudely lozenge-shaped flake, measuring about 53 x 34 x 12 inches.
On the more weathered surface we find a shallow hollow, roughly
resembling an ear in shape, and about ? inch long, which leads to a
tube slightly oval in section and about + inch in diameter. This
passes obliquely through the fragment and is exposed on the other—
apparently more recently broken—surface, where it continues as a
branching channel for rather more than an inch and can be traced
interruptedly for about # inch farther. On one side of this, and
probably connected with it, traces are found of another branching
tube; the tube is lined as before with a film of a blackish glassy
material, as will be described below; and patches of it can be seen
on the first-named surface forming more or less branching patterns,
one group being probably connected with the mouth of the tube.

The last specimen (represented by the third analysis, p. 456) is
apparently a loose fragment, about 53 inches in length and rudely
triangular in a cross section, the longest side being about 2 inches,
with weathered fawn-coloured surfaces. Neither tubes nor channels
can be detected, but there are (mostly on one side) several filmy
patches of the black ‘ pitted’ glassy material, irregular in outline,
two of them extending continuously for a full inch.

These fulgurites, it will be seen, bear a general resemblance to
those collected by Mr. Eccles from the summit of Monte Viso and
excellently described by Mr. F. Rutley,' except that in our specimens

7 Quart. Journ. Geol. Soc. vol. xlv. (1889) p. 60. See also, for the general
aspect of the tubes, the illustration on pl. iii., where, however, the channels
ramify rather more than in the cases described above.

‘ 212

458 MISS E, ASTON AND PROF, BONNEY ON [Aug. 1896,

the lining of glass is perhaps a shade thinner, and the material isa
little different.

As it seemed hopeless to obtain a thin slice of the rock so as to
retain a good section of the actual lining of a tube,’ a little of this
crust was flaked off and examined, when powdered, under the
microscope. It was taken from the second of the above-named
specimens. The lighter-coloured material (from the inner part of
the tubes) consists of a very dark brown glass (only translucent in:
the very thinnest chips or edges), in which flakelets of the serpen-
tinous mineral,’ common in the rock-mass, are not infrequently
embedded. The black material (external part) is similar, so far as-
can be ascertained, but here any approach to translucency is rare,.
and the above-named minerals indicate their presence only by
occasionally projecting from the edges or making almost the whole-
thickness of a chip.

It then occurred to us to. examine the glass which could be
obtained by artificial fusion of this rock. A small flake was:
detached from one end of the third of the above-described specimens..
This was not affected by the ordinary blowpipe-flame, but was.
fused at the edges and on the adjacent surface by supplying oxygen.
instead of air; that is to say at a temperature which certainly
exceeded 1700° C., or was well above the melting-point of pure iron.
In this operation the thinner parts of the flake were fused and a
small detached pellet—seemingly of glass,—about =, inch in diameter,
was obtained, but on breaking up these the former proved to be
only a pellicle of glass—rarely attaining 4, inch in thickness, and
the latter to consist of an unmelted core of rock, covered by a film
of glass varying from about ;3, to +, inch. This glass also was of
a very dark brown colour, and its surface was slightly pitted with
minute depressions ; in fact it was practically identical with that.
which had been produced by the lightning. Samples from each
were crushed, mounted,’ and examined under the microscope with
various magnifications up to about 400. The glass, so far as can
be seen, does not differ in any respect from that produced by the
lightning. Only the thinnest parts are translucent, and these are
of a deep umber-brown colour, like the darkest varieties of tachylyte.
As in the other case it includes flake-like minerals, between which
it can be seen, as it were, to penetrate, so that a transitional zone
separates that of complete fusion from the unfused rock, both of
these zones being very narrow. In the first-named many mineral

* One of the slices had accidentally intersected a tube, but nothing satisfactory
could be made out from the fragments of fused material that still adhered. It
does, however, indicate that the minerals immediately below the glass assume,
for a very short distance, a cloudy aspect, due, so far as can be seen, to the
development of extremely minute cavities, sometimes tubular.—T. G. B.

2 I contrived to measure the extinction in some; generally it was straight, but
in one or two cases it appears to be slightly oblique. Both tints (mentioned
already) were noted.—T. G. B. .

* I am indebted to Miss C. A. Raisin, B.Sc., for preparing the slides of glass
used in this paper, and for independently examining them so as to verify my
results.—T. G. B.

‘Vol. 52.] NICKEL-BEARING SERPENTINE. 459

flakes occur, more or less prismatic in outline: these usually give
straight extinction and fairly high polarization-tints. Probably

‘they are antigorite. The other constituent (or constituents) has

evidently proved more fusible,’ so that a structure imitating that
called ophitic has been produced. In some cases the fused part

exists as minute specks or granular patches, or it forms streaks,

which are either ‘ knobby’ or irregular, or like fibres with forked
ends. Both these products seem to follow cleavage-planes, and the

latter present a tubular aspect, but as the threads are so minute
(less than 54,5 inch in diameter) it is difficult to be sure of this
-matter.

A little of the brown glass, spattered on the ‘ green schist’ from

the Hornli, has been examined in like way: the chips of this are in
_all important respects so similar to the glass described and figured

by Mr. Rutley in his account of the Monte Viso fulgurites that no

further description of its characters is necessary.

The extreme thinness of the slaggy crust, the smoothness of the
underlying surface of the tube, and the rapid passage from the one

-to the other in the case of the serpentine, are remarkable. These
‘tubes look as if they had been drilled with a fine boring-tool, and
afterwards coated with a viscous or ‘slaggy’ varnish, in the
smaking of which only the more fusible parts of the rock have been

melted. The holes themselves, except for their sinuous course,
wremind one on a small scale of the perforation made by a rifle-bullet
an arather soft material, or that driven through a steel armour-
plate by the bolt from a large cannon. The material thus removed
appears for the most part to have been blown away to some distance,
for we do not find it deposited at the mouth of the orifice.

Discussion.

Prof. Ramsay mentioned that, a few days before the visit of
Mr. Eccles and himself to the Riffelhorn, they had spent a con-
siderable time on the Gorner Glacier, watching the lightning striking
the Riffelhorn. It is not improbable that the fulgurites found were
formed on this occasion. He mentioned a fulgurite which he had
found in 1891 on the summit of Cir Mhor in Arran, in which a slab,
a segment of a sphere, nearly a yard in diameter, had been dislodged
from one of the blocks of granite of which the hill consists. The
granite was glazed, as was also the dislodged slab. He had visited
the spot every year since, and at present all trace of glaze has dis-
appeared, owing to the weathering of the rock. He also remarked
on the probability of the presence of arsenide of nickel in the
rock.

Mr. Rutter commented on associations of nickel with serpentine.
The percentage of nickel oxide shown in the analysis was very
high, compared with the amounts, seldom reaching 1 per cent., in

1 T think that, in both the natural and the artificial fusings, the dark glass is
formed by the melting together of the granules of augite and of iron oxide, and
the serpentinous minerals have proved more refractory.—T. G. B.

460 NICKEL-BEARING SERPENTINE WITH FULGURITES. ([ Aug. 1896,.

analyses of serpentines from North Carolina and elsewhere.
Mr. Eccles had informed him that the fulgurites described in the
paper did not appear to penetrate the rock to any great depth, and
that they seemed ultimately to branch and thin off. This accorded -
with observations which he had already made concerning the
probable terminations of certain fulgurites of the sand-tube type..
He alluded to an exceptional case, in which a few crystallites were

present in fulgurite-glass. In all other cases with which he was

acquainted such glass showed no inclusions other than gas-pores..
Miss Aston’s analysis was one of considerable value and interest.

So far as he knew, this was the only recorded case of the occurrence:
of fulgurites in serpentine.

Dr. Pretier, having witnessed the effects of violent lightning-
discharges in various parts of the Alps, observed that mountain--
peaks, such as the Riffelhorn and Monte Viso, in which occurred
serpentine or other magnetite-bearing rocks, appeared to be subject
more especially to direct lightning-discharges, producing perforations -
similar to those described by Prof. Bonney and Mr. Rutley; while~
limestone peaks, such as the Stanserhorn near the Lake of Lucerne,.
and Mont Saleve near Geneva, appeared to be more frequently struck.
by indirect, that is, meandering or side discharges. He quoted.
a specific case which occurred within his knowledge on the Stanser-.
horn two years ago, when an indirect discharge only left black marks.
on going to earth through the electric installation erected on the-
lower of the two limestone peaks. He thought that abundant:
evidence of the effects of atmospheric electricity upon rocks.
would be found in the Western Islands of Scotland, which, being~
chiefly basaltic, contained a large percentage of magnetic iron, andi
which Profs. Rucker and Thorpe had shown to lie in a magnetic:
zone.

Mr. Ecctzs also spoke.

Prof. Bonney thanked the Fellows for the reception which they
had given to the paper, and said that it was quite true that some
nickel was generally found in a serpentine, but that, so far as he:
could ascertain, anything like 4:9 per cent. was exceptional.

Wols 522) GLOBIGERINA-LIMESTONES OF MALTA, 461

23. Nores concerning certain Linzar Marxs in a Sepimentary Rock.
By Prof. J. E. Tatmaer, D.Sc., F.G.S. (Read March 11th,

1896.
) [ Abstract. ]

Tue marks described in the paper occur in a fine-grained argil-
laceous sandstone referred by the U.S. Geological Survey to the
Triassic or Jura-Trias period, which is found on a low tableland
within 2 miles of the bluffs overlooking Glen Canyon. The marks
commonly appear as straight lines intersecting at right angles, but
some have a pinnate distribution, suggesting engravings of frost-
flowers. A description of the markings is given, and various
experiments made in the laboratory to illustrate the effects of
formation of crystals formed over sediment are described. (See a
paper by the same Author in the Utah University Quarterly for
December 1899.)

24. The Gypsum Deposits of NorrineHAaMsHIRE and DERBYSHIRE.
By A. T. Mercatre, Esq., F.G.S. (Read January 8th, 1896.)

[ Abstract. |

THE gypsum deposits of these counties occur in the Upper Marls
of the Keuper division of the Triassic system. The author describes
their occurrence in thick nodular irregular beds, large spheroidal
masses, and lenticular intercalations, and their association with satin-
spar, alabaster, selenite, and anhydrite.

25. Conrrisutions to the SrraticraPHy and PaLmontoLoey of the
GLOBIGERINA-LIMESTONES of the Matrese Istanps, By J. H.
Cooxs, Esq., F.L.S., F.G.8. (Read April 15th, 1896.)

[ Abstract. |

A BIBLIOGRAPHY of the Globigerina-limestones is followed by some
remarks on the physical features and general distribution of the
strata. The limestones are divided into nine subdivisions, lettered A
to I, the former being uppermost. Four seams of phosphatic nodules
form the subdivisions B, D, G, and I, and local nodule-bands also
occur in E. The subdivision G serves as a line of demarcation
between the Langhian Series (Miocene) and the Aquitanian
(Oligocene). Details of the lithological and paleontological cha-
racters of the various subdivisions are given, and the Author
concludes that I and the lower part of H were laid down on a
sinking sea-floor, in about 300 fathoms of water; that the upper

462 G@LOBIGERINA-LIMESIONES OF MALTA. [Aug. 1896,

part of Hand G, F, E, D, composed to a large extent of Globigermma
and other pelagic organisms, were probably deposited in about
1000 fathoms; while C, B, and A were probably laid down, like I
and the lower part of H, in about 300 fathoms of water.

Discussion.

Dr. J. W. Grecory expressed his appreciation of the work done
by the Author in zonal collecting from Malta. He was glad to
find that his detailed collections supported the correlation and
classification of the Maltese rocks which the speaker had suggested
from the study of the Echinoidea.

Dr. Woopwarp expressed regret that he had not arranged to send
up from the British Museum (Natural History) a series of specimens
left with him in illustration of this paper. He bore testimony to the
great labour which the Author had expended in conducting the
researches on the Globigerina-limestones of Malta, to the working
out of which he had been urged by Dr. John Murray. The Author
had not only laboured to perfect the paleontology, but had also
had several analyses made by chemists to strengthen the evidence
in his paper.

Wol. 52.] PHOSPHATIC CHALK AT LEWES. 463

26. On a PuospHatic CHALK with Hotaster pLaAnus at Lewes. By
A. Srrawan, Esq., M.A., F.G.S. With an Apprnpix on the
ForaMINIFERA and Ostracopa. By F. Caapman, Esq., A.L.S.,
F.R.M.S. (Communicated by permission of the Director-
General of H.M. Geological Survey. Read March 25th, 1896.)

In 1891 I described before this Society a phosphatic chalk which
occurred near the top of the Upper Chalk of Taplow, and resembled
the deposits long known and worked in Belgium and the North of
France, but not up to that time recognized in this country.’ Up to
the present, in spite of much searching, no other occurrence of this
rock has been recorded in England, but during the summer of 1895
Mr. John Rhodes, fossil collector to the Geological Survey, while
engaged in collecting from the great chalk-pits near Lewes, noticed
a thin band bearing a strong resemblance to the Taplow phosphatic
chalk. At the request of the Director-General I visited the spot
and made the following notes.

The pit, which is marked on the 6-inch and 1-inch (new series)
Ordnance maps as the Southerham Pit, lies on the south-western
side of the high downs of Upper Chalk which overlook Lewes from
the east. A somewhat marked syncline traverses the central part
of these hills in an east-and-west direction. Thus Lewes, situated
nearly on the synclinal axis, stands on Upper Chalk, but both to
the north and south of the Downs the Middle and Lower Chalk
emerge with southerly and northerly dips respectively. The
Southerham Pit extends from the Middle to high up in the Upper
Chalk, but the workings in the Middle Chalk have been abandoned
and are partly obscured. A small bank, however, at the eastern end
of the long line of limekilns affords a good view of the junction of
the Upper and Middle subdivisions and of the phosphatic band in
question. Though only about 20 yards in length, the cutting suffices
to show the impersistent character of the deposit. To illustrate
this I give three sections taken at intervals of about 10 yards,

About the middle of the Cutting.

Massive chalk with flints. ft. ins.
Flaky white chalk with a few flints and Holaster planus ... 4 0O
passing down into
Phosphatic chalk with many small fish-teeth, a few spines of
Cidaris and some nodules, partly green, partly brown, up
Raa MEME TET. UATOCLOT Ci «ic cnicdis sassinwnnnde ovdesitydaust-c dacs exeses 1 6
A sharp line of demarcation. .
Hard creamy limestone with calcite in veins and cavities,
nodular (some of the nodules being green-coated), lumps of

GECOMIBGAEMMTON-PYTItEs'...........100seccnsecnccnsecestececuteae 1 6
Hard, white, compact chalk, traversed by branching pipes and
thin lamin of phosphatic chalk...............c..-ssceseeceeeees a 0

Hard, white, compact chalk, with the pipes and laminz of
phosphatic chalk less abundantand dying away downward. 3 0

1 Quart. Journ. Geol. Soc, vol. xlvii. (1891) p.356; see also ‘ Natural Science,’
vol. i. no. 4, p. 284, and Geol. Mag. 1895, p. 336.

464 MR. A. STRAHAN ON A PHOSPHATIC CHALK _[ Aug. 1896,

Ten yards west of the above.

Massive chalk with flints, some paramoudra. ft. ins

Hlaky chalk wir few Gimbs 1. sseerecn see eee te eneoener hee aise 4 0
passing down into

Phosphatic chalk, poor in phosphatic grains ..................+6. 1 0

iPhosphatic chalks sricherye ©: ssascmurperae ct pzes.ss.cct see ee tees I 4

Hard creamy nodular limestone, as above.

Ten yards east of the first Section.

Flaky chalk with flints, a very few phosphatic grains at the

base. A small, nearly spherical flint, 2 inches from the

base, contained some: Prams gee .c.n-.- 0-2 oceeeterereereeencee
Hard nodular limestone, as above .........-<-.e.:cccscsecsccrese- 1 0
Hard white chalk, piped with phosphatic chalk, as above. ... 3 0

The hard nodular limestone referred to in the above sections not
only resembles the Chalk Rock, but occurs at the horizon assigned to
that. stratum on stratigraphical evidence. The fossils collected by
Rhodes confirm this view. Specimens from the Upper Chalk worked
in the northern part of the pit included, according to the identifi-
cation of Mr. Sharman, the following forms :—

Ventriculites decurrens. Crisina.

Serpula wliwm. Entalophora.
Cidaris-spine. Rhynchonella Mantelliana.
» clavigera-spine. * plicatils.
Bourgueticrinus. Terebratula semiglobosa.

Echinocorys vulgaris. Terebratulina gracilis.

Micraster cor-bovis. Bs striata.
fe cor-testudinarium. Inoceramus Cuviert ?

Salenia. Lima spinosa.

The beds assigned to the Chalk Rock contained :—

Cidaris-spines. Terebratula semiglobosa.
Folaster planus, Mant. (about Terebratulina gracilis.
4 feet above the phosphatic
band).

In the phosphatic band fish-remains abounded, both minute
pellets and teeth. Among the latter Mr. E. T. Newton, F.R.S.,
identified :—

Corax falcatus. | Oxyrhina (a tooth about
Odontaspis. # inch long),

An exposure of the Middle Chalk.a few yards south of the out-
crop of the Chalk Rock yielded :—

Ventriculites. Spondylus striatus.
Lima spinosa. Fish-remains.
Ostrea Normaniana.

While the lowest beds seen in the pit contained :—

Ehynchonella Cuvieri. Inoceramus mytiloides..
Terebratula semiglobosa.

Vol. 52.) WITH HOLASTER PLANUS AT LEWES. 465

The whole exposure therefore ranges from the Micraster-zones-
of the Upper Chalk to the Rhynchonella Cuvieri-zone of the Middle
Chalk inclusive, and the brown chalk may be referred with certainty
to the horizon of the Chalk Rock. In this respect alone it differs:
from the phosphatic chalk of Taplow, which occurred in the zone
of Belemnitella quadrata, 20 feet only below the base of the
Tertiary deposits of that neighbourhood.

The Southerham phosphatic chalk resembles that of Taplow so
closely in composition that its description may be dismissed in a
few words. It consists of a white chalky matrix in which are
embedded a multitude of brown grains. In weathered specimens
these grains can be washed out in water, but the separation can be
better effected by dilute acetic acid, which removes almost all the
matrix, but scarcely corrodes the brown grains. Mr. Player, to:
whom I was indebted for the chemical examination of the Taplow
Chalk, confirmed my opinion that the brown grains from Southerham.
also consist largely of phosphate of lime. They resemble those of
the Taplow Chalk so nearly that he did not consider it necessary to:
make a full analysis. The Taplow grains were found by him to
contain 50°6 per cent. of phosphate of lime, while the rock in its.
raw state contained 18 to 35 per cent.’ The Southerham brown
chalk in the raw state is probably rather less rich than the Taplow
material, and this, taken in connexion with the fact that it is
thin and impersistent, seems likely to preclude it from proving of
economic value.

The microscope also shows a complete resemblance between the
residue of the Southerham and Taplow chalks, after treatment with
acetic acid. In the former the oval pellets which were determined
as the coprolites of small fishes are rather more abundant and larger,
but proportionate in size to the numerous teeth which occur. The
prisms of Jnoceramus-shell are rather less common, but internal
casts of foraminifera form a large proportion of the residues, and
small amber-coloured chips of bone occur equally in both. A thin
slice of the raw rock shows the clear shells of the foraminifera
surrounding the internal phosphatic casts.” The reactions with
polarized light are the same in both rocks. When treated with
hydrochloric acid some of the foraminifera are seen to have been
filled with a greenish mineral resembling glauconite, the proportion
so filled being rather larger in the Southerham than in the
Taplow Chalk, especially in the greenish nodules which occur in
the phosphatic band. Further details of either chemical or micro-
scopical examination of the rock would be a mere repetition of the
account of the Taplow Chalk given in this Journal (vol. xlvii. 1891,
pp. 358-362).

The flint referred to in the third section as occurring 2 inches
above the rocky floor is seen under the microscope to contain many

? Quart. Journ. Geol. Soe. vol. xlvii. (1891) p. 358.

> Pl. xx. fig. 2 in ‘Deep Sea Deposits’ (Challenger Reports) shows recent
foraminifera from a depth of 1900 fathoms similarly infiltrated. The illustra-
tion closely represents the appearance of the organisms of the phosphatic chalk.

A66 MR. A. STRAHAN ON A PHOSPHATIC CHALK [ Aug. 1896,

foraminifera, silicified, and not easily distinguishable from the
matrix. Some, however, have been filled with a brown mineral
resembling the phosphate of the phosphatic chalk; in such the
shell only has been silicified, the carbonate having been replaced
more readily than the phosphate of lime, as might have been
expected.

The existence of these two stratigraphically distinct deposits
throws additional light on the origin of phosphatic chalks generally,
for it enables us to select with greater certainty the phenomena
which accompany the formation of such arock. The characteristics
which are common to both may be enumerated as follows :—

1. The abundance of organic remains (pellets, teeth, and bone-
fragments), which originally contained phosphate of lime.

‘2. The phosphatization of organisms (foraminifera and _ shell-
prisms) which were originally composed of carbonate of lime.

<3. The impersistent character of the deposits.

A, The association of the deposits with a floor of hard nodular
ehalk,

5. The perforation of the white chalk beneath this floor by
branching tubes filled with phosphatic chalk.

1, 2, & 3. On the first two of these points I dwelt at some length
in my former paper; the impersistent character of the deposits
-which was suggested by the non-appearance of the Taplow phos-
phatic Chalk elsewhere seems now to be confirmed by the fact that
‘tthe Southerham Chalk thins away or passes into ordinary white
chalk within a few yards. The Continental deposits, moreover,
which have been extensively worked, form lenticles rarely exceeding
1 kilometre in length and about 200 or 300 metres in breadth.

4, But the association of the deposit with a hard floor and the
perforation of the chalk beneath by tubes filled with phosphatic
chalk acquire some significance from being repeated in a different
locality and at a different horizon.

Such floors are far from uncommon. One of the best known and
most extensive is that known as the Chalk Rock, but they occur
also at all horizons in the Upper and Middle Chalk. They are
specially characterized by an unusual hardness and a nodular or
lumpy structure; by the presence of glauconite either as casts of
microscopic organisms or as coating the nodules; and by a slight
increase in the proportion of phosphate of lime either disseminated
through the rock or filling the small organisms.

The unusual hardness of the floors on which the phosphatic chalks
of Taplow and Southerham rest suggested partial phosphatization
of the rock. This, however, was disproved by an analysis by
Mr. Player which showed the presence of only avery small quantity
of phosphoric acid; nor was silica or magnesia present in sufficient
quantity to account for the character of the rock, the composition
of which, in fact, scarcely differs from that of ordinary chalk.

The existence of calcite in veins and cavities is an unusual feature,
and suggested that the hardness might be due to a crystalline

Vol. 52.] WITH HOLASTER PLANUS AT LEWES. 467

cement. Under the microscope, however, the rock isseen to
consist of an amorphous calcareous paste, enclosing numerous
foraminifera, though not nearly in such abundance as the phosphatic
chalk. The foraminifera, many of which are perfect, are filled with
the same material as that which forms the matrix. No foreign
minerals were observed.

In spite of the negative character of the microscopic evidence, it
seemed not unlikely that the replacement of the carbonate of lime
(in the organisms which were originally calcareous) by an acid
phosphate had set free carbonic acid, and led to the production of
a soluble bicarbonate of lime. A solution of this coming into
contact with the underlying and less permeable white chalk might
have hardened it by infiltration, and might explain also the existence
of the calcite in the joints and cavities.

But it must be remembered that the association of phosphatic
chalk with these floors is the exception and not the rule. Though
the hardened chalk underlies the phosphatic chalk in both the
English sections, and in some of the Continental occurrences also, in
the great majority of cases these rock-bands are overlain by white
chalk of the normal character. Their lumpy and nodular structure
seems then to suggest a concretionary action, probably accompanying
a pause or change in the sedimentation ; that the action was contem-
poraneous is proved by the fact that small organisms not unfrequently
adhere to the nodules."

Before quitting the subject I should mention that in the Chalk
Rock there is evidence of something more than a mere change in
the sedimentation. It has long been known that the fauna of this
horizon is peculiar, especially on account of the presence of certain
gasteropoda; foreign detritus, moreover, becomes more abundant in
this band than elsewhere in the Upper Chalk. Dr. Hume, as a
result of an exhaustive examination of the residues and conditions
of deposit of the Chalk, concludes that ‘ lithological evidence points
to the close of the Middle Chalk period as having been a time of
change, probably in the direction of re-elevation. The paleonto-
logical facts seem peculiarly striking in this respect.’ Holaster,
Ammonites, and Scaphites, which were last met with in abundance
in the Grey Chalk, return in the Chalk Rock, and the arenaceous
foraminifera, the abundant quartz-grains from the residues, the
crystals of tourmaline, were all left behind in the Grey Chalk, but
reappear in the Chalk Rock. He shows, too, that the other mollusca
also were affected. ‘ Turbo gemmatus and forms of T’rochus and
Solarium again resume their place among the important fossils of this
series. The trochoid forms are the last to disappear during depression,
and they are also the first to reappear during elevation.’ ?

* Hill & Jukes-Browne, Quart. Journ. Geol. Soc. vol. xlii. (1886) p. 230;
see pig i Geology of the Isle of Wight,’ 2nd ed. Geol. Surv. Mem. 1889,
pp: 78, 79.

2 «Ocean Deposits, Ancient and Modern, by W. F. Hume, ‘Natural
Science,’ vol. vii. (1895) p. 390; and ‘Chemical and Micro-Minera logical
Researches on the Upper Cretaceous Zones of the South of England,’ 1893.

468 MR. A. STRAHAN ON A PHOSPHATIC CHALK [ Aug. 1896,

Without, perhaps, inferring actual re-elevation on this evidence, I
should so far agree with Dr. Hume that the rock has originated in
a decided, though temporary, change in the conditions under which
the Chalk was being deposited. ‘To suppose a change to have taken
place in the strength or direction of the local currents seems less
violent than to assume a reversal of the movement of the earth’s
crust.

The glauconite and phosphate of lime occur in the form and
position in which they were deposited, for a large proportion of both
fills the interior of more or less perfect foraminifera. In this respect
the glauconite differs from that found in the Greensands, where
it occurs as loose grains seldom enclosed in their original moulds
and generally with an appearance of having been corroded. Both
minerals, as shown in the Challenger Reports (‘ Deep Sea Deposits,’
pp. 382, 383), are being formed on the sea-bottom at the present
day, and in constant association. Glauconite appears in its most
typical form and greatest abundance along high and bold coasts
where no rivers enter the sea and where accumulation is not rapid.
Between 200 and 300 fathoms it is more abundant than in deeper
water, and though glauconitic casts have been met with at depths
of over 2000 fathoms, they are stated never to occur in truly pelagic
deposits (op. cit. p. 396). Its occurrence, therefore, in the phosphatic
chalk indicates a comparatively shallow-water origin for the rock.
The foraminifera, though, as shown by Mr. Chapman in the appendix,
indicating a deeper-water origin for the Southerham than for the
Taplow phosphatic chalk, support this inference, while the mode of
occurrence of the phosphate points in the same direction, for the
source of the phosphoric acid seems undoubtedly to lie in the
remains of fish which lived on the spot, and which are unlikely to
have been inhabitants of the deeper part of the ocean. This accords
also with the view that has been suggested by what we know of
the limits of the Chalk-sea, namely, that no part of the English Chalk
was formed far from land, and presumably, therefore, none in any
great depth of water." We may perhaps infer with some probability
that the Southerham phosphatic chalk was formed at a depth of
between 200 and 600 fathoms.

In the same volume (‘ Deep Sea Deposits,’ pp. 396, 397) it is
pointed out ‘ that phosphatic nodules are apparently more abundant
in deposits along coasts where there are great and rapid changes of
temperature, arising from the meeting of warm and cold currents.
... It seems highly probable that in these places large numbers of
pelazic organisms are frequently killed by these changes of tempe-
rature, and may in some cases form a considerable layer of decom-
posing matter on the bottom of the ocean.’ The same thing is
stated to occur where large quantities of fresh water are thrown

into salt water by floods.
The facts observable in connexion with the phosphatic chalk

1 On this subject see also ‘On the Microscopic Structure of the Zones of the
Chalk,’ by A. J. Jukes-Browne, Proc. Yorks. Geol. & Pol. Soe. vol. xii. part y.

(1894).

Vol. 52.] WITH HOLASTER PLANUS AT LEWES. 469

-seem only in part reconcilable with such a theory as the above, as to
its origin. The rocky floors mark the pause or interruption in the

sedimentation caused by the change of current, while the probably
accompanying change of temperature would help in explaining the
presence of the glauconite and phosphates. On the other hand, it

should be remembered that the phosphatic deposits bear internal
evidence, in the shape of the abundant excreta, of having been a

feeding-ground rather than a burial-place.

5. On the fifth point of resemblance between the Taplow and
Southerham sections, namely, the perforation of the underlying white
chalk by branching tubes filled with the phosphatized variety, I have
found little to throw any additional light. The tubes are rounded,
and, being filled with a material markedly different from the sur-
rounding rock, are well-defined.’ The phosphatic chalk in these
exactly resembles that of the phosphatic stratum itself; it, more-
over, spreads here and there for a few inches along planes of
current-bedding in the white chalk. The tubes range up to an
inch in diameter and run vertically as often as in any other direc-
tion; they branch frequently and irregularly.

These tubes perhaps approach ‘ Spongia paradoxica’ more nearly
than any other structure with which I am acquainted, except in being
generally smaller. The origin of this so-called organism remains
doubtful after much discussion. Prof. Hughes has argued in favour

of the structure being wholly concretionary *; but in the present

case, where there is a marked difference between the contents of
the tube and the surrounding rock, his arguments would not apply.
It seems necessary to suppose that the tubes existed as such, and
were open, and that phosphatized organisms were being occasionally
washed about, while the white chalk was being deposited. Against
their being the borings of molluscs,’ or casts of the hollows left by
seaweeds or annelids, various objections may be urged, and on the
whole Zittel’s supposition with respect to ‘ Spongia paradoxica,’
that it is the cast of a horny sponge, seems the most applicable in
the present case also.

Conclusions.

The close resemblance of the Southerham chalk, at the base of
the Upper Chalk, to the Taplow chalk, at the top of that formation,
indicates that the conditions under which such a deposit was formed

were not confined to any one zone. ‘They may probably have
recurred at any horizon in the Chalk.

The conclusion formed with regard to the Taplow phosphatic

1 A thin section across one of the tubes and the surrounding matrix was
described in my former paper, Quart. Journ. Geol. Soe. vol. xlvii. (1891) p. 358.

2 Quart. Journ. Geol. Soc. vol. xl. (1884) p. 276 and discussion.

8 M. de Mercey, in describing a nodular chalk which forms the top of the
Micraster-zone, speaks of it as being sometimes pierced by Pholades. Numerous

tubulures penetrate it deeply. Bull. Soc. Géol. France, ser. 2, vol. xx. (1863)
p. 635.

470 MR. F. CHAPMAN ON THE [ Aug: 1896,

chalk, that the concentration of the phosphoric acid was the work
of small fishes, is strengthened by the fact that the remains of such
animals are still more abundant in the Southerham chalk.

The deposits seem to have some connexion with hard nodular
floors which are believed to mark changes or pauses in the sedimen—
tation, accompanied by contemporaneous concretionary action.
Though presenting points of similarity with phosphatized Globi-—
gerina-ooze, they are not pelagic deposits.’

The same cause which delayed the sedimentation (whether change
of current or otherwise) seems occasionally to have led to the
assembling of multitudes of small fishes, but rather by providing
them with food than by causing their destruction.

Apprnpix By F. Cuapman, Esq., A.L.S., F.R.M.S.

THE FoRAMINIFERA AND OsTRACODA.

* The following notes and accompanying list are the result of an
examination—(1) of some unweathered phosphatic chalk, which
was crushed and levigated; (2) of about fifteen mounts of specimens
selected by Mr. J. Bennie, together with other specimens which L
obtained from similar material, and which had been taken from a
weathered surface of the same phosphatic band.

The foraminifera and ostracoda from each of the samples differed
so materially from one another in their general facies that it seemed
advisable to keep the two lists separate. One noteworthy difference:
is the occurrence of six species of ostracoda in sample 2, and only
one species in sample 1. There is also a predominance of arena-
ceous forms in sample 1, mainly belonging to the Textulariide;
while the members of the Lagenide largely obtain in sample 2.
This latter, along with the occurrence of the ostracoda, points to
the shallower condition of the water for sample 2.

The foraminifera are, with few exceptions, either entirely phos-
phatized, or they are infilled with phosphate of lime. This is
clearly seen by examining material which has been treated with.
weak acetic acid, some of the specimens retaining their usual out-
line and superficial markings, while others are represented only by
the form of the chamber-cavities of the shell, and have the delicate:
stolon-passages preserved in relief by the infilling process.

The foraminiteral facies of the Southerham chalk appears to differ
very essentially from that of the phosphatic chalk of Taplow,’ but it
agrees exactly with the fact of its being on a lower horizon than
the latter rock, since there is a noticeable scarcity of truly Upper
Chalk forms in the material under discussion.

Forty-two species and varieties of foraminifera and six species of

1 [In reading the paper I used here the expression ‘shallow water’ in place
of ‘not pelagic.’ This did not, however, convey the meaning I intended, and
led to an apparent difference of opinion in the discussion.—May 15th, 1896.]

2 ¥. Chapman, Quart. Journ. Geol. Soc. vol. xlviii. (1892) p. 514.

Vol. 52.] FORAMINIFERA AND OSTRACODA. 471

ostracoda are here recorded from the chalk of Southerham. The
ostracoda are all known from the Chalk.

As regards the foraminifera, only 57 per cent. of the forms from
Southerham are found at Taplow; and, from the evidence afforded
by a comparison of the two faunas, that of the Southerham chalk
seems to be of deeper-water origin than the one from Taplow.

The family of the Miliolide is represented in the Taplow chalk
by no less than seven species, while only a doubtful glauconite-cast
of a Miliolina has been collected from the Southerham chalk.

The family of the Lituolide is represented in the Southerham
chalk by two species of Haplophragmium, the Taplow chalk yielding
no example.

The next family—the Textulariide—is one of the best repre-
sented in the Southerham chalk, and comprises Textularia (3 forms),
Tritaaa (3), Spiroplecta (1), Gaudryina (3), and Bulimina (5).
The species are represented in the Taplow chalk, with the excep-
tions of Tritaxia pyramidata, Reuss (also abundant in the Chalk
Marl and Gault), Gaudryina pupoides, dOrb., Bulimina polystropha,
Reuss, and B. pupoides, d’'Orb. The siphonate Tritaxia, T. foveo-
lata, Marsson, was also found in the Taplow chalk, but not recorded,
and I am indebted to Mr. F. W. Millett for directing my attention
to its occurrence there. |

The family of the Lagenidx, while it is fairly well represented
in the Southerham chalk by some genera, is conspicuously poor in
those having delicate tests such as Lagena, Lingulina, Frondicularza,
and Polymorphina, all of which are recorded from the Taplow chalk.
It is possible that examples of genera such as these may have been
destroyed by subsequent disturbances of the deposit; but it is,
perhaps, more probable that their absence may be accounted for by
the bathymetrical conditions, seeing that these genera are usually
found in fairly shallow water.

Of the Globigerinide, Globsgerina equilateralis, Brady, is con-
spicuously rare in the Chalk of Southerham.

The Rotaliide are remarkably few in number, being represented
by five genera only, with as many species. By far the most interesting
form in this family from the Southerham chalk is Gypsina crete
(Marsson).' The species is here recorded for the first time from
the English Chalk, and was described by Dr. Marsson from the
White Chalk of Riigen.

See full lists on next page.

In concluding these notes I wish to express my obligations to
Prof. J. W. Judd, 0.B., LL.D., F.R.S., who very kindly gave me
facilities for working out these results in the Geological Laboratory
of the Royal College of Science.

| Acervulina crete, Marsson, 1878, Mitth, Nat. Ver. Neu-Vorpommern u.
Rigen, vol. x. p. 171, pl. v. fig. 39a & 5.

Q.J.G.S. No. 207. : 2K

FoRAMINIFERA,

Sample No. 1.

No. Name. Sample No. 2.
1. | ? Miliolina seminulwm (L.) «12.02.0004. 1 specimen.
2. | Haplophragmium irregulare (Rom.)...,) —...-- 1 specimen.
3. 53 CUCUUUE (ELAR) seseces| | cmene's 1 specimen.
4, | Textularia globulosa, hr. ............... frequent.
we if " var. striata(Ehr.)| frequent.
6. ¥3 prochws, 0 Orb: eas .ceh hs .0: 1 specimen. 1 specimen.
7. | Tritaxia tricarinata, Reuss ............ 1 specimen. rare,
8. » pyramidata, Reuss ............ frequent. frequent.
9. » foveolata, Marsson ............ rare.
10. | Spiroplecta annectens (P. & J.) ......... frequent. 1 specimen,
Il. | Gaudryina rugosa, d’'Orb. .......0.+00+05 rare.
12. c Pupoides, WOT a ascae'en' common. 1 specimen.
13. 98 Jonesiana, Wright ......... 1 specimen.
14. | Bulimina polystropha, Reuss ............| seve 1 specimen.
15. " OUWUSE.U OLD! fo oc. ooo e case ets frequent.
16. 2 pupoides, WOLD. .....cé0sesse- 1 specimen.
17. Mi Murchisoniana, d’Orb. ...... 1 specimen.
18. 4 GHISA OLDE 26 oncadadnssonaet rare.
19. | Nodosaria consobrina, d’Orb. ............] eeaeee rare.
20. bs communis, d’Orb, .......... 1 specimen.
21. | Rhabdogonium tricarinatum, var. acut-
ANGWUN TE ROUSS |). cael). ckdetannstnvceessc| he eens 1 specimen.
22. | Marginulina equivoca, Reuss ......0.| sees 1 specimen.
23. | Vaginulina recta, Reuss ............-.02<| . seeees 1 specimen.
24. | Cristellaria cultrata (Montf.) ......... frequent. common.
25. a rotulata (Lam.) ............ common. common.
26. ne wgaultingd, Berths» ....425.003|0 0 mapebenee rare.
Zi x MOCHA SE OFDs ccecacssesseeha) wh Perce 1 specimen.
28. ‘i acutauricularis (F. & M.).) sas. 1 specimen.
29. ss GeO0G, COLD. ss .ceusstensens 1 specimen. frequent.
SMM MRRHEC DEON, BD. 2 )....cccos-ececoncceseceafie | piheeamec fragment.
31. | Polymorphina fusiformis (Rémer)......) =... 1 specimen.
32. | Ramulina aculeata, Wright ............| seeee rare. .
33. * VEUtS, PONES, sa cacene -eeeecente 1 specimen. 1 specimen.
34. | Globigerina cretacea, WOrb. .........+.- common. frequent.
35. if marginata (Reuss) ......... very common. | common.
36. "4 bulloides, VOrb. ..........- rare,
37. 2 equilateralis, Brady ...... 1 specimen.
38. | Discorbina Bertheloti (d’Orb.)..........-- 1 specimen.
39. | Anomalina ammonoides (Reuss) ......... very common. | very common.
40. | ? Pulvinulina elegans (d’Orb.) ......... 1 specimen.
41. | Rotalia Soldanii, d’Orb. .........c0..0000: common.
42. | Gypsina crete, Marsson ............006++- 1 specimen.
OstRACODA.
No. Name. Sample No. 1. | Sample No. 2.
1. | Bairdia subdeltoidea (Minster) .........) ss. frequent.
2. | Cythereis auriculata (Cornuel) .........) sees 1 specimen.
3 5 ornatissima, Reuss, var. pau-
POPE; PACU meee Sate Poneslel 3 (l ssp <siee 1 specimen.
4. | Cytherella Muenstert (Rom.) ............ 1 specimen. common.
5 ss QUaTA, (HOME) Visencctchotescl eee very common.
6 3 QUOURTG: HORM seat weeeemealnh | wkd 1 specimen.

Vol.c2.] _ PHOSPHATIC CHALK AT LEWES. 473

Discussion,

Dr. W. F. Hume remarked that it is notable that the phosphatic
chalks in England are not only so rare, but are also connected with
nodular conditions. The Middle Chalk in the South-East of England
has usually two prominent zones of nodular character—one at the
pase, the Melbourn Rock ; the other at the summit, the Chalk Rock.
Between these the chalk is fine-grained, and only contains minute
fossils. At Lewes, however, the conditions are somewhat different,
the nodular conditions being several times repeated, while pebbles,
fragments of wood, large Inocerami and Ammonites, all suggest the
possibility of current-conditions at this particular locality. It is
therefore particularly interesting to find the phosphatic chalk here.
It is also noticeable that the foraminiferal fauna, as mentioned by
Mr. Chapman, has here a deeper aspect than that at Taplow, the
same statement holding good when compared with the Lower Chalk
foraminifera.

Dr. G. J. Hive could confirm the very close resemblance of the
Lewes phosphatic chalk to that of Taplow. He did not agree with
the Author in considering the deposit of shallow-water origin, for
microscopic sections showed that the rock was a purely organic
deposit without admixture of clastic materials; it was, in fact,
similar in its constituents to a Globigerina-ooze, and was probably
formed under much the same conditions of depth as this latter.

The AutHor was interested in hearing from Dr. Hume of an
abnormal character in the Chalk near Lewes; such observations
tended to throw light on the origin of phosphatic chalk. His inference
as to the shallow-water origin of the deposit was founded on ob-
servations made in the Challenger Reports on the formation of
glauconite and phosphate. He agreed with Dr. Hinde as to the
absence or great scarcity of clastic material. The term ‘shallow
water’ required definition: by it he meant any depth between 200
and 600 fathoms. Undoubtedly the phosphatic chalk strongly
resembled Globigerina-ooze, in fact the plate in the Challenger
Reports illustrating phosphatized ooze would serve also for phos-
phatic chalk; but in the latter glauconite has been formed in some
abundance, and we learn from the Challenger Reports that this
mineral is not now being formed in truly pelagic deposits, such as the
Globigerina-ooze.

2x2

474 SUBMERGED LAND-SURFACES AT BARRY. [Aug. 1896-

27. On SUBMERGED Lanp-surFAcEs at Barry, GLAMORGANSHIRE.
By A. Srrawan, Esq., M.A., F.G.8. With Norxs on the Fauna —
and Fiona by Crement Rep, Esg., F.LS., F.G.8.; and an
APPENDIX on the Microzoa by Prof. T. R. Jonus, F.R.S., and
F. Cuapman, Esq., A.L.S., F.R.M.S. (Communicated by per-
mission of the Director-General of H.M. Geological Survey.
Read March 25th, 1896.)

Barry Istanp lies off the northern coast of the Bristol Channel, -
about 7 miles south-west of Cardiff. Until the year 1884 it was
separated from the mainland by the tidal estuary of the Cadoxton
River on its northern side, and on the east by a tract covered at high
water, but in which the solid rock cropped up through the tidal
deposits at frequent intervals, the most conspicuous prominences
being known as the Coston, Mark, Bendrick, and Black Rocks.

In the absence of evidence to the contrary we may assume that
the course followed by the river at this time was its original course,
for it falls into the general south-westerly direction of the rest of —
the valley. The numerous outcrops of rock, moreover, in the tidal
area east of the island make it unlikely that there was an outlet
here of sufficient depth to drain the marshes behind it. This tidal
area seems to have been one of three low cols in the water-parting
on the southern side of the Cadoxton Valley. One of these would
separate the western part, or the Little Island, from the main part —
of Barry Island were it not for a ridge of blown sand; another
occurs east of Hayes Farm, where, as shown by the Ordnance level 19
given on the map facing this page, the alluvial marsh of the Cadoxton
River closely approaches the present coast. The third, presumably
a trifle lower than either of the others, was submerged during the
subsidence of the land, of which proof will be given in the following
paper. It was therefore as a direct consequence of this subsidence
that Barry was separated from Hayes Farm and became an island,
while a slight increase in the extent of the movement would have:
given us three islands instead of one as the result of the submer-
gence of the old water-parting.

As to the date of the insulation of Barry, it will be seen subse=
quently that it had not taken place before Neolithic times ; on the
other hand the island is, I believe, referred to as such in the earliest
historical records.

In 1884 the Barry Docks were commenced. The river was
diverted from its ancient course and carried to the sea by an
artificial cut east of the gap referred to. Its former valley on the
northern side of the island was partly filled up and partly excavated
to form a dock, the entrances to which were made in the tidal area
east of the island, the sea being excluded by a wall. Subsequently
a second dock (shown on the map as ‘ Barry Docks Extension’) was:
commenced in this reclaimed area, and it was the excavation made

BARRY ISLAND & NEIGHBOURHOOD.

Srom the Six-Inch Ordnance Maps
published in 1885.

The Barry Docks, Sea Walls, etc. have been added from.a

map by Mr Fames Bell (1893). 3 ZA
Outcrops of solid vock between tide-narks shewn huss Es
Scale:2 Inches to the Mile.
: }
" i aaeee® ee ; . 1g
Senet : a SS a
Biehl aa EY Siete er 0
Lf (AS a ree =
. “ 8 > Fe ne . ‘2.
7 wen aifee a] “
rd i : S siarren 8 8 120“ pa
F a" : ON ee cS Sos \ *
her pS AN RY = id
)M.29 4 ;

SCOSTON Rock s= SYK
SSS

=~

4 es .

wate
TREHARNES PT=2~(L0M

_ PAs Pes ¢ “ . 7 and

476 MR. Ae STRAHAN ON SUBMERGED LAND-SURFACES [Aug. 1896,

for this purpose that I had the opportunity of examining in the
course of my duties on the Geological Survey in 1895.

The history of the invasion of the river-valley by the sea through.
the gap mentioned clearly reveals itself in the sequence of deposits ;
but, more than this, the river-alluvium presents a series of freshwater
beds and land-surfaces, whose position in relation to the present.
sea-level proves that a great change in the level of the land took
place during and after Neolithic times.

On some of my visits to the Dock I had the advantage of the
assistance of Mr. F.T. Howard, F.G.S., and of Mr. J. Storrie, to the:
latter of whom I am indebted for much information respecting the:
sections exposed in the earlier dock, and also for the identification
of some of the specimens from the present excavation. To my
colleague Mr. Clement Reid, however, I am indebted for a thorough
examination of the whole of my specimens, and for the identification.
of both plants and shells, together with critical remarks thereon.
Prof. Rupert Jones, F.R.S., has kindly furnished me with the list
of ostracoda, etc., given in the Appendix.

The natural topography of the tract.is preserved on the 6-inch
Ordnance maps, Glamorgan L. and LI. (published 1885, surveyed in
1878), from which the accompanying map (p. 475) has been prepared..
The high-water mark of ordinary tides being shown on these maps.
in the usual manner, we are able to see that the whole of the new
dock is being excavated in ground that was covered at high tide,
though it pretty closely approaches the eastern shore at a point
known as Warren ump (now levelled). The extreme southern.
point of the dock lies near what was formerly a shoal known as
Coston Rock. In both these parts the excavation is principally in
the solid rock, but elsewhere it generally fails to reach the bottom
of the alluvial deposits. These may be enumerated as follows :—

. Blown Sand.
. Scrobicularia-clay. j ecw subaerial and tidal deposits.
. Sand and gravel.
Strong line of erosion.
Blue silt, with many sedges.
The Upper Peat Bed ; about 4 feet below Ordnance-datum.
. Blue silty clay, with many sedges.
. The Second Peat, a thin layer only.
. Blue silty clay, as no. 6.
. The Third Peat, many large logs and stools, and roots in place underneath ;
about 20 feet below Ordnance-datum.
. Blue silty clay, with reeds, willow-leaves, and freshwater shells.
11. The Fourth Peat, with large trees and roots in place. Land-shells.
numerous,
12. An old soil with roots and land-shells; about 35 feet below Ordnance—
datum.
Rock in place.

COWIRDOB oboe

—
fo)

By the kindness of Mr. James Bell, Engineer to the Barry Dock
Company, I have been furnished with the following levels :—

Vol. 52.] AT BARRY, GLAMORGANSHIRE. 477

Above Below
Ordnance- Ordnance*
datum. datum.

feet. feet.
Quay-level, coping round Dock, Basin and Deep Lock ...| 26°50
High-water ordinary spring tides ................sssecsee seeee 19°70
Tigh-water ordinary noap tides »-2......0-.-....scesecesseveseecs 11°30
RTE AHO REI aos ck clcwaidsvavadacheascdeesess coats 1:60
Low-water ordinary neap tides .......0.....sscsceeeecsesseeees 83
Low-water ordinary spring tides ..............cscecocsseseeceeees 16°4
PERE WHEN 2 ec Sons coterie Sbat ones cdaencaieFnwacwenssases 20:0

1. The blown sand occurs only on the eastern side of the tidal area,
whence it was evidently drifted by the south-west winds. The
supply was never great, and is now of course entirely cut off.

2. The Scrobicularia-clay occurs in considerable force towards the
north-eastern end of the excavation. It is a stiff, brownish
clay, jointing vertically as it dries. It contains an abundance
of Scrobicularta plana, with the valves united, and in this
and other respects resembles the mud which is now being
deposited in the more sheltered parts of the Bristol Channel.
In the present case it found no rest on the shoals east of the
island, but accumulated in some force from near Warren Tump
upwards along the river-valley, as indicated on the map.
The greatest thickness seen in the dock was 9 feet.

3. This sand and shingle forms the base of the Scrodicularia-clay,
into which it passes insensibly upward. It ranges from 2 to
8 feet in thickness, according to local circumstances, and is full
everywhere of recent shore-shells, all more or less rolled.
Among these the following species have been identified by
Mr. Clement Reid:—Serobicularia plana, Tellina balthica (the
thin-shelled estuarine form), Cardium edule, Patella vulgata,
LIittorina littorea, L. rudis, and L. obtusata.

Southward this sandy and gravelly tidal wash extends in a
patchy manner among the rocky shoals towards the present foreshore,
where it is still in course of formation. The deposits described
above were all in process of being laid down, until the area was
taken in hand by the Barry Dock Company in 1884. They rest
upon a conspicuously eroded surface of the strata about to be
described, with which also they contrast strongly in their contents ©
and character. ‘The erosion is attributable to the scour of the tide
when the sea first gained access to the estuary round the eastern
end of the island.

The series of deposits upon the description of which we now enter
forms a continuous sequence from top to bottom. It may gene-
rally be described as a mass of fine clayey silt with abundant remains
of sedges in the position of growth throughout, and with four or
more bands of peat, only three of which, however, are of any
importance. For convenience of reference I have numbered the
beds all through, but the clays or silts which fall under the figures
4+, 6, and 8 are practically identical. The greatest thickness seen
amounted to about 35 feet.

Section through Barry Extension Dock, 1895.

N.W.
Near

Entrance.
'

Southern
angle
of Dock

e
Fe ee
@M f
Ba
ie
<=
>kE>
Osan
= ao
@2

Near
centre of
Dock

roo yards

Scale for Vertical and Horizontal distances.
5oyds..,

0 10203040 506070 8090 roo ft.

Estuarine
Deposits, etc.

, ete. |

0 = Blue silt with sedges
1 = Peat Beds.

oil below Lowest Peat Bed

6, 8, 1
7, 9, 1

5)
b)

4
5
1

Recent Marine
Deposits.

Scrobicularia-clay.
Sand and gravel.

2
3

4. Over the eastern and southern
parts of the excavation, a thick-
ness of blue silt ranging from
1 to 6 feet lies next below the
recent tidal deposits, but on the
north-western side, the tidal
erosion having been somewhat
greater, this uppermost silt has
been washed away and the tidal
deposits rest directly upon the
peat-bed no. 5. The silt, like
the others to be described, i
crowded throughout with the
roots and rotten stems of sedges
in the position of growth, while
at the bottom a few foraminifera
(see Appendix, p. 485) give the
deposit a_ slightly estuarine
character.

5. This peat-bed forms one of the
most conspicuous bands in the
series. It ranges from 1 to 2
feet in thickness and persists
over the whole of the excavation
(and, as I was informed by Mr.
Storrie, through the old dock also)
except in those parts where the
rock-surface rises in one of the
shoals referred to. In such cases
the peat-bed, slightly rising as it
approaches the rock, thins away
to a feather-edge, but comes in
again at its proper level as the
rock-surface falls. It keeps at
a fairly constant level of about
4 feet below Ordnance-datum.
Where fully developed it presents
the following details :—

5a. Laminated peat with logs
(including, according to Mr.
Storrie, willow, fir, and oak),
passing down into

56. Light-coloured flexible marl,
composed of the shells of ostra-
coda with much vegetable matter.

5c. Shell-marl composed princi-
pally of the shells of Limnea,
Bythima, ete., with many ostra-
coda and much vegetable matter.

5d. Peat with logs of oak, ete. (one
measuring 5 feet in length by

Vol. 52.] SUBMERGED LAND-SURFACES AT BARRY. 479

10 inches in diameter). A Neolithic worked flint was found
by Mr. Storrie in this bed.

The ostracod- and shell-marls occurring in this peat are best
developed in the southern angle of the excavation. As the peat-bed
approaches the flanks of one of the rock-shoals previously referred to,
it curves slightly upward, and in such cases the shell-marls thin
out; at the same time logs of wood become more abundant. It
may be supposed that these slightly inclined portions of the peat
were formed at the margin of the water in which tke shell-marls
were accumulating, and that the logs were stranded in the positions
which they now occupy.

The worked flint referred to was found by Mr. John Storrie after
T had left the district. He picked it out from the peat (5d), three
inches below the shell-marl, and within half a yard of it noted a
stone containing glauconitic grains in the shell-marl (5c). The
implement is made from a light grey chalk-flint, derived possibly
from the drift-deposits of the district. Sir Johu Evans, to whom
I showed the specimen, determined it to be a broken fragment
of a polished celt, and Prof. Hughes further pointed out to me that
it seems to have been used subsequently as a strike-a-light. The
fragment is only about an inch long, but shows parts of the two
ground faces of the celt, and of one of the ground edges; it can be
matched exactly in shape (and, as it happens, in colour) by a
polished celt from Mildenhall in Suffolk, which was given me for .
comparison by Prof. Hughes.

It may be mentioned here that two bone-needles, now in the
Cardiff Museum, are said to have been found in this peat-bed during
the construction of the first Barry Dock.

The only bone which I have seen or heard of was a fragment of an
antler, probably of red deer, which had been thrown aside by the
workmen. It clearly came from some part of the freshwater series.

The ostracod-marl (5 6) has been examined for me by Prof. Rupert
Jones, F.R.S., who furnishes the full list of forms given in the
Appendix. The brackish or freshwater Cytheridea torosa, Jones,
forms the bulk of the deposit. The shell-marl (5c) is considered by
Mr. Clement: Reid to have been formed in a nearly freshwater tidal
marsh. It consists mainly of Limnea and decayed Chara. He
determines also the following shells and plants :—

Succinea elegans. Bythinia tentaculata,
Velletia lacustris. Entomostraca.
Limnea auricularia.
peregra. Rumex crispus.
Planorbis albus. Atriplex.
—— nautileus. Saliz.
—— nitidus. Potamogeton.
Valvata piscinalis. Naias marina.
cristata. Chara, two species.

Mr. Reid remarks that the occurrence of the pine (as identified
by Mr. Storrie) and of Naias marina, both plants unknown in Wales
during the historic period, suffices to distinguish this peat from any
recent deposit.

480 MR. A. STRAHAN ON SUBMERGED LAND-SURFACES [Aug. 1896,

6. This blue silty clay precisely resembles no. 4. It ranges from
5 to 7 feet in thickness.

7. The second peat is an impersistent brown band never exceeding
8 inches, and averaging about 3 inchesin thickness. Its upper
and lower limits are indefinite, and it suggests merely that:
for the time being plant-remains were accumulating more
rapidly than mud. Mr. Reid describes it as ‘a marsh-peat,
apparently composed mainly of sedges (Scirpus maritimus).’

8. This resembles nos. 6 and 4, and is from 5 to 7 feet thick. In
its upper part, immediately under the peat-bed no. 7, it con-
tains shells, among which Mr. Reid identifies Melampus
myosotis, Helix arbustorum, Pupa, and Hydrobia ventosa.

Upright stems of a sedge, probably Scirpus maritimus, occur
throughout this bed as through all the other silts.

9. This peat occurs at or close to the bottom of the dock—that is, at
20 feet below Ordnance-datum. It rarely exceeds 8 inches in
thickness, but is persistent. In several places it is made up
almost entirely of large timber, both trunks and stools of trees,
while in one section roots and rootlets extending downward
from the peat into a soil composed of disintegrated Keuper

Marl were finely displayed. I give the section at this point
in full :—

Section about the middle of the North-western side of the Dock.

feet. inches..

2. Brown clay with Scrobicwlaria,........sessececesssessssrees Oto 1 0
38. Sand and gravel with recent marine shells............... dees 5

Line of erosion.
La pe 22 reer 3a Sor ASANBON (aA Sn pRB MOE dics sdoduaedoncs: conasossucouganoaanae 1 6
G6, Blue tsiliy clay ite catscssacw-hn'serctscceeeaboreneaerencses ses cece Ts
Wes Peat yc 5h aid sat soe tite antec soe kena eee eRe Rane one es octmee 3 to 4
8. Blue wsilltyyelayyl 4. 9-4 qee tbh veeioan te demeen a cee meet meena cient nec 5 O
9. Peat with large logs, including some of oak ...............+.. 3 to 8

Decomposed green Keuper Marls, traversed by roots in
position of growth and joining on to the peat above.
Among the roots are some of conifers ...... ....s.esseeeee 310

Close by this spot the rock-surface rises on the flanks of one
of the shoals referred to above; the beds thin out in succession
against this slope (as shown in the section on p. 478), and it
is tor this reason that the sequence ends here with No. 9.
The clear exposure left no doubt that the roots and rootlets
were embedded in the position of growth in their native
soil, nor was there any difficulty in tracing them upward
into the mass of rotten wood that constituted the peat. In
examining this section I had the advantage of the assistance
of Mr. Storrie, to whom I am indebted for the identification
of the woods.

Mr. Reid describes a specimen of this peat collected at a
few yards distance as consisting of ‘a tough mass of vegetable
matter, principally sallow and reed, both roots and stems.

Vol. 52.] AT BARRY, GLAMORGANSHIRE. 481

It also contains seeds of Valeriana officinalis and Carex, and
elytra of beetles. There is no evidence of salt water.’ I inter
that the peat was formed in the one case as a true forest-bed
along the margin of a swamp, and in the other by the growth
of water-weeds within the limits of the morass.

10 and 11. These strata lay below the dock-bottom and were
exposed only in the excavation for the foundations of walls,
etc. Fortunately a good exposure of the important part of
them was accessible about halfway between the entrance and
the southern angle of the dock. The section commenced at the
dock-bottom—that is, at the peat last described (no. 9); in the
upper part it was timbered up, but at a depth of about 9 feet
blue silty clay (no. 10) of the usual character could be seen and
dug out through the timbers ; at 12 feet below the dock-bottom
the silt was succeeded by peat no. 11, and from here downward
the section was open.

Section below the Dock-bottom south of the Entrance.

feet. inches.

Not seen, but according to information all blue silty clay. 10
10. ; Blue and greenish silt, full of reeds and containing leaves
and land-shells ; in the upper part foraminifera ...... 2 0
Ea WALA AUCH, CHMMDEI <2. <5). cot nwe so waka tun danse ace anceseaecws 3 4
12. Reddish clayey gravel with land-shells and penetrated by
roots in place; passing down into red and green grits,
limestone, and marls.

With the exception of the foraminifera from the lower part
of the silt (no. 10), there is nothing in this section to suggest the
presence of salt or brackish water. The list of the microscopic
organisms is contributed in the Appendix with the remark that the
bed is quite marine, but the molluscs and plants enumerated below
seem to modify this conclusion.

The red clayey gravel below was an unstratified deposit, including
large angular fragments of the underlying rock. It was traversed
by a network of roots ranging up to 3 inches in diameter, one of
which at least was connected with one of the masses of wood
in the peat above. Some of them also had moulded themselves
against or between the angular blocks of rock, as would happen
with roots growing in such a soil. Many had small twigs attached
to them, while much of the deposit was more or less traversed by
root-fibres. Some roots ran horizontally, but many vertically, and
of the latter several were followed down for 3 feet below the base
of the peat without reaching their terminations. The rock at
this point is rising somewhat sharply, so much so that within 50
yards it touches the Upper Peat (nv. 5), as shown in the section
on p. 478. It might, therefore, have yielded some talus, but the
gravel was totally unstratified and seemed rather to be rock decom-
posed in place. The evidence leaves no room for doubt that this
peat is an old land-surface, lying at a depth of 35 feet below the
present Ordnance-datum,

A482 MR. A. STRAHAN ON SUBMERGED LAND-SURFACES [ Aug. 1896,

Mr. Clement Reid furnishes me with the following information
respecting these deposits :—

10. This greenish sandy silt is full of reeds and contains leaves of
willow, and land- and freshwater shells, such as Limnea
auricularia, Planorbis albus, P. nautileus, Hydrobia ventrosa,
Valvata piscinalis, and V. cristata; Salix caprea and Phrag-
mites.

11. This peat contains much broken oak-wood, mixed with seeds
and shells, Hyalinia (Zonites), ete. A thin seam is full of
willow-leaves and contains ostracoda, Hyalinia, and apparently
Pisidiwm and Planorbis; the shells are much crushed.

Oak, Quercus robur (wood).

Hazel, Corylus avellana (twigs and nut).
Cornel, Cornus sanguinea (seeds).
Hawthorn, Cratequs oxyacantha (seeds).
Bur-reed, Sparganiwm (seeds).

Sallow, Salix caprea (leaves).

12. This old soil contains :—

Bird (femur of small species about the size of the stint).

Charychium minimum. Pupa.
Helix arbustorum., Valvata piscinalis.
rotundaia. Cardium edule, two fragments
hispida. (? brought by gulls).
Hyalinia. Crategus oxyacantha (seed).
Succinea. Cornus sanguinea (seed).
Limnea truncatula, Quercus robur (wood).

Mr. Reid concludes from his examination of the specimens that
the lowest land-surface represents a true forest-growth, such as
could only live at an elevation clear of the highest tides; one tide
in the year would have sufficed to alter markedly the character of
the fauna and flora in the deposit. Subsequently to the growth of
this oak-forest a slow subsidence seems to have taken place, turning
the land-surface into a shallow lake full of reeds and freshwater
shells, the only indication of any salt being the occurrence of
Hydrobia ventrosa, a shell which is seldom found in purely fresh
‘water, and the foraminifera enumerated in the Appendix. The third
peat (no. 9) Mr. Reid judges from the specimen submitted to him
to indicate swampy ground rather than a true land-surface, but it
will be remembered that in another section the existence of roots
in place beneath the bed was clearly shown. The silt above (no. 8)
he judges to be estuarine in its upper part, where it yielded fora-
minifera, Melampus myosotis, H lydr obia ventrosa, Helix arbustorum,
and Pupa, while the peat (no. 7) he considers to be a compressed
mass of sedges and not a land-surface. Of the highest peat (no. 5)
Mr. Reid remarks that the contained fossils suggest at first a purely
freshwater origin, but closer examination shows a noticeable
absence of all species that are sensitive to the addition of a little
salt, and one of the plants, Naias marina, is usually found within
the reach of an occasional tide. The Nazas, he points out, is of
special interest, for at the present day it is known from Britain in
one locality only, in Norfolk, though it occurs also in the Cromer

Vel. gay AT BARRY, GLAMORGANSHIRE. 483,

Forest Bed. Its recent distribution on the Continent is also very
partial, but its seeds have lately been noted in abundance in peaty
deposits, perhaps of the same age as those of Barry, in parts of
Sweden and Holstein.

Mr. Reid remarks also that there is nothing in the fauna or
flora to indicate any change of climate.

The facts detailed above seem to admit of but one explanation,
namely, that the land has subsided at least 55 feet since the forma-
tion of peat no. 11. In dealing with such deposits we have to bear
in mind that the sea is capable of raising barriers against itself, and
that behind such barriers freshwater deposits may be forming, or
even a land-surface may exist at a level below that of the highest
tides, though never below mean sea-level. As bearing on this
question I have noted from the Ordnance-map the levels of some
of the marshes now bordering the Bristol Channel :-—

Feet above

Ordnance-datum.
Sully Moors, the alluvial flat of the Cadoxton River,

DGB ADOWE MB ATNY: <6 ea-0ccecbetasec ss sdcaracenye qsiteceas 18
Cardiff (Grange Town), near the Taff River ......... 18
SPAT GME. PASE WO OES enon esnes aac dons nars<snnesnnaswsaccepsee 20 to 22

y near the Rhymney River ......... 18
Oardiit (Cooper's Wields) (22.0323 4.02300. ved wcesediesenises 25
Peterstone Wentloog, 1 mile N.W. of .................. 15

is - 1 mile N.E. of, and near a

BOM gp cet tade actatspuncup'sesstsaescscesesesvaccesaeuddececs 13

In all these cases, except perhaps the Cooper’s Fields, the tide:
would occasionally overflow the land, were it not artificially kept
out. Assuming for the sake of argument that a surface 20 feet
above Ordnance-datum is the lowest that would now be safe from
such periodic incursions of salt water, we have 55 feet as the
difference in level between the land-surface, peat no.11, and the
lowest possible at the present day. At Porthkerry, 14 mile west
of Barry, a small stream with an alluvial flat about 150 yards broad
debouches upon the shore. The sea has blocked the valley by a
barrier of shingle, through which the fresh water escapes by perco-
lation. The alluvial flat is liable to floods, though not, I believe,
through the incursion of salt water, but only by the ponding back
of the fresh. The level of this marsh is about 40 feet above:
Ordnance-datum, or 75 feet above the lowest peat (no. 11) of Barry
Dock.

In none of these alluvial flats, nor elsewhere in the Bristol
Channel, do we approach conditions under which the Barry Dock
deposits could have been formed. If we assume that the sea had
raised against itself an effectual barrier at the mouth of the Cadoxton
River, and that it had not yet gained access to the river-valley by
the gap on the eastern side of the island, we must then allow the
existence of a freshwater lake, for the land-water would accumulate
behind the barrier to at least mean sea-level. That is to say, we
should have to assume that water stood at a depth of over 36 feet
where we find evidence of a land-surface, with forest trees growing

A484 SUBMERGED LAND-SURFACES AT BARRY. [Aug. 1896,

im place and abundant land-shells. The same sort of evidence, in a
searcely less striking degree, is presented by every layer from the
bottom to the very top of the series. There is, in fact, no part of
it that could be formed with the land at its present level.

It will be noticed that the Cadoxton River flows for much of its
course over Keuper Marls and the conglomerate or limestone which
form the base of that series, but that at the coast it traverses the
Carboniferous Limestone. In the softer rock its valley is broad and
occupied by the alluvial flat, of which the Sully and Cadoxton
Moors form part, but in the Carboniferous Limestone it narrows
down to about 100 yards. It was in this broad area of obstructed
drainage that the deposits described above accumulated, and no
doubt the regularity with which they were laid down, and the
gentleness with which estuarine influence was occasionally in-
sinuated, was largely due to the narrowness of the outlet. At the
time of the earliest land-surface, when the land stood not less than
55 feet higher than at present, the sea must have been still farther
removed, but how much farther it is not possible to say. Though
the Carboniferous Limestone would waste with extreme slowness,
there may have been extensive post-Glacial deposits outside Barry
Island, of which the Bristol Channel tides would make short work,
so that itis doubtful how far the contours of the present sea-bottom
are those of a submerged Jand-surface, or to what extent they have
been modified by marine erosion. It is worth noticing that the only
part of the Bristol Channel, south and east of Barry, which exceeds
60 feet in depth is a rather narrow trough about 2 miles south of
the Welsh coast.

At any rate, we may suppose that the alluvial flat of the Sully
and Cadoxton Moors occupies what was a generally freshwater
estuary, occasionally dry enough to support a forest-growth on its
margins, but as a rule swampy and densely overgrown with sedges,
etc. By a more or less continuous sinking of the land the swamp
tended to become a shallow lake, nearly but not wholly beyond the
reach of the tide, until the subsidence admitted the sea by the gap
east of Barry, thus separating that island from the mainland, and
burying the estuarine series under true marine and tidal muds.
The occurrence of the fragment of a polished flint-implement in the
uppermost peat proves that the subsidence was in progress in
Neolithic times, but had not yet sufficed to insulate Barry Island.

In conclusion, IJ should mention that there is a copious literature
on both submerged forests and raised beaches in the Bristol Channel.
The re-survey of the district, however, by the Geological Survey
being in progress, I hope that much fresh information will be forth-
coming, and I have confined myself to a description of the one section
that I have had an opportunity of examining, more especially as
that section seemed unusually complete in itself. In dealing with
the subject generally, both the earlier upward movement implied by
the raised beaches, and the later downward movement proved by
the submerged land-surfaces, I shall hope to do full justice to my

numerous predecessors.

Wolk. 5224 MICROZOA FROM BARRY DOCK. 485

APPENDIX.

Report on the Microzoa 7m Mart and Six1s from Barry Dock,
near CARDIFF.

[This has been drawn up by Mr. Freprrick Cuapman, A.L.S.,
¥F.R.M.S., with the advice and co-operation of Prof. T. Rupert Jongs,
F.R.S., F.G.S. ]

A, Osrracopa.
(1) From the Clay above Upper Peat (No. 4 of p. 478).

1. CyrHERIDEA ToRosA (Jones), var. TERES, Brady and Robertson.
See above, p. 479.

This has been previously recorded from Cardiff (New Dock Basin).
‘Two specimens.

2. Loxoconcua Ettirtica, G. 8. Brady.

L. elliptica, G.S. Brady, 1868, Trans. Linn. Soc. vol. xxvi. p. 435,
pl. xxvii. figs. 38, 39, 45-48; pl. xl. fig. 3.
Previously recorded from Cardiff (New Dock Basin). Frequent.

(2) From the Upper Peat (No. 56 of p. 478).
1. Canpona puBESCcENS (Koch).

Cypris pubescens, Koch, 1837, ‘ Deutschlands Crustaceen,’ etc.
Heft xi. p. 5.

Cypris setigera, Jones, 1857, Monogr. Tert. Entom. (Pal. Soc.)
p. 12, pl. i. fig. 6.

Candona compressa, Brady, 1868, Trans. Linn. Soc. vol. xxvi.
p. 382, pl. xxvi. figs. 22-27.
~ Candona pubescens, Brady & Norman, 1889, Sci. Trans. R.
Dublin Soe. ser. 2, vol. iv. p. 101, pl. xii. figs. 32-37 (limbs, etc.).

This species has been recorded from post-Tertiary deposits in
Berkshire and Cambridgeshire; and it occurs as a recent fresh-
water form in Great Britain and Europe.

Examples still bearing the short bristles on the exterior of the
‘valves are found in the deposit from Barry Dock. Frequent.

2. CANDONA SUBZQUALIs, Jones.

C. subequalis, Jones, 1857, Monogr. Tert. Entom. (Pal. Soc.)
p. 20, pl. 1. figs. 9 a—c.

This is already known as a post-Tertiary freshwater form from
Essex.

Two specimens; Barry Dock.

3, CANDONA CANDIDA (Miiller).

Cypris candida, Miller, 1785, Entom., ete. p. 62, pl. vi. figs. 7-9.

Candona candida, Baird, 1845, Trans. Berwick. Nat. Club, vol. ii.
p. 153 ; Jones, 1857, Monogr. Tert. Entom. (Pal. Soc.) p. 19, pl. i.
figs. 8a-f; Brady and Norman, Sci. Trans. R. Dublin Soe. ser. 2,
vol. iv. 1889, p. 98, pl. x. figs. 1, 2, & 14-23 (including varieties).

*

436 MR. F, CHAPMAN AND PROF. T.R. JONES [ Aug. 1806,

A Pliocene, post-Tertiary, and recent freshwater species.
Frequent, Barry Dock.

4, Canpona LacTEA, Baird.

Candona lactea, Brady and Norman, 1889, Sci. Trans. R. Dublin
Soc. ser. 2, vol. iv. p. 100.

A post-Tertiary and recent freshwater species; Great Britain
_and Europe.
Frequent ; Barry Dock.

5. Darwinva Stevensoni, Brady and Robertson.

Darwinella Stevensoni, Brady and Robertson, 1874, Monogr. post-
Tert. Entom. (Pal. Soc.) p. 141, pl. 11. figs. 13-17.

Darwinula Stevenson, Brady and Norman, 1889, Sci. Trans. R.
Dublin Soe. ser. 2, vol. iv. p. 122, pl. x. figs. 7-13.

A Pliocene, post-Tertiary, and recent freshwater species ; Great:
Britain and Europe.

Common; Barry Dock.

6. LimnicyTHERE rNopinata (Baird).

Limnicythere nopinata, Brady, 1868, Trans. Linn. Soc. vol. xxv.
p. 419, pl. xxix. figs. 15-18, pl. xxxviii. fig. 9, pl. xxxix. fig. 1.

This strikingly sculptured species is a post-Tertiary and recent
form; inhabiting fresh and estuarine waters, and found sometimes.
in seawater near the coast.

Very common; Barry Dock.

7. CYTHERIDEA TOROSA (Jones), var. TERES, Brady and Robertson.

C. torosa, var. teres, Brady and Robertson, Ann. Mag. Nat. Hist.
1870, ser. 4, vol. vii. pp. 21, 22; Brady, Crosskey, and Robertson,
1874, Monogr. Post-tert. Entom. p. 178, pl. vii. figs. 1, 2.

This variety is distinguished from the type by the absence of the
knobs so conspicuous in C. torosa. The specimens here under
notice vary very much in size, measuring =, to;4, inch (0°42 mm. to
1°38 mm.) in length. The external surfaces of the valves are
marked with minute pittings, disposed in a somewhat concentrically
lineate manner. The usual transverse median sulcus is well-marked
in nearly all the specimens, but it is better developed in the larger
individuals. There is a short stout spine on the margin of the right
valve at the posterior ventral angle. The valves of the male are
narrower and more elongate than those of the female.

Previously known as a Pliocene, post-Tertiary, and recent fresh-
water and estuarine form; Great Britain and Europe.

Very abundant ; Barry Dock.

(3) From the Clay above the Lowest Peat (No. 10 of p. 481).

1. CyrHERE PELLUCIDA, Baird.
C. pellucida, Brady and Norman, 1889, Sci. Trans. R. Dublin
Soc. ser. 2, vol. iv. p. 126, pl. xiv. figs. 13-15.

Vol. 52.] ON INE MICROZOA FROM BARRY DOCK, 487

This is an essentially brackish-water species, and has been before
recorded from Cardiff (New Dock Basin) amongst other places.

Common.
2. CrrHErvRa Propucta, G. S. Brady.
C. producta, G. 8. Brady, 1868, Trans. Linn. Soc. vol. xxvi.

p. 443, pl. xxxil. figs. 60, 61.
This species has been previously found at Cardiff (New Dock

Basin). One specimen.

B. FoRAMINIFERA.

From From Clay (No.10)

From Clay U
(No. 4) above ae above Lowest
Upper Peat. (No. 5 8). Peat.

Miliolina oblonga (Montagu) 2
subrotunda (Montagu) ...... 1
Cornuspira involvens, Reuss ...... ai 3
Trochammina inflata (Montagu) .| Frequent. 1
1 3

, var. macrescens, B. H.

Brady.
Textularia trochus, V’Orbigny ... 1 small specimen.
Bolivina textularioides, Reuss ... sas Common,
1 1

Lagena globosa (Montagu) ......

heii (Montara)... sss 002. 1 ie
Polymorphina lactea (W. & J.) ... v5 1 small specimen.
Discorbina rosacea (d’Orb.) ...... i 2
Bertheloti (VOrb.) ......... uh J
Guise (AOE) x. c5hsceener is kK 1
Truncatulina Ungeriana (d’Orb.) sf be 1
Rotalia Beccarii(Linné). Dwarfed| Common. 2 Frequent.
specimens.
Nonionina depressula (W. & J.)...| | Common. ane Very common.
Polystomella striatopunctata (F.| Very common. 1 Very common.
& M.).
Frequent.

Dendrophora erecta (Str. Wright)

1. ? DenpRopHrya ERECTA, Strethill Wright.

Dendrophyra erecta, Str. Wright, 1861, Ann. & Mag. Nat. Hist.
ser. 3, vol. viii. p. 122, pl. iv. figs. 4 & 5. ’

Fragments of tubes, composed of loose sandy material, and usually
tapering at one end, after the manner of the above form. There
can be hardly any doubt that these post-Tertiary specimens are
referable to the above species.

Frequent; Barry Dock.

2. LacEna Lavis (Montagu).

Lagena levis, Williamson, 1848, Ann. & Mag. Nat. Hist. ser. 2,
& Vok.4. p. 12; plod: figs )a2:

A very minute, but perfect, example of this species; from Barry
Dock.

Q.J.G.8. No. 207. 21

488 MR. A. STRAHAN ON SUBMERGED LAND-SURFACES [ Aug. 1896

3. LacEena etososa (Montagu).

Entosolema globosa, Parker and Jones, 1857, Ann. & Mag. Nat.
Hist. ser. 2, vol. xix. p. 278, pl. xi. figs. 25-29.

Lagena globosa, Reuss, 1868, Sitzungsb. k. Akad. Wiss. Wien,
vol. xlvi. p. 318, pl. 1. figs. 1-3.

A very small individual; from Barry Dock.
4, Discorprna Rosacea (d’Orb.).

Discorbina rosacea, Parker, Jones and Brady, 1865, Ann. & Mag.
Nat Wnistasery a. volloxcvinp. 20, pl. 1. fis. (1.

One specimen, of fair size; Barry Dock.
5. DiscorBina optusa (d’Orb.).

Discorbina obtusa, Brady, 1884, Rep. Chall. Foram. p. 644, pl. xa.
hee.

A young example of this form, with but few chambers.
One specimen ; Barry Dock.
6. Roratra Bucoarr (Linné).

Rotalia Beccarit, Brady, 1884, Rep. Chall. Foram. p. 704, pl. evi.
figs. 2 & 3.

Young specimens, but typical.
Two examples; Barry Dock.
7. PotysroMELLA stRiaTopuNcTATA (Fichtel and Moll).

Polystomella striatopunctata, Brady, Rep. Chall. Foram. p. 733,
pl. cix. figs. 22, 23.

One specimen, of rather small size; Barry Dock.

C. Pranraz.
From the Upper Peat (No. 56 of p. 478).

Nucules and stem-fragments of Chara, sp.; Campylodiscus (Dia-
tomaceze).

From the Clay above the Lowest Peat (No. 10 of p. 481).
Campylodiscus. Frequent.

The lowest portion is quite marine; the higher upward one goes
the more estuarine the material becomes.

Discussion.

Prof. T. Rupert Jones referred to the importance of foraminifera
as giving evidence of the presence of sea-watcr ; and stated that some
of the entomostraca from the ostracod-marl had a brackish-water
habitat. He mentioned that the examination of the specimens was
made by Mr. Chapman, and that he had only given help and advice.

The Prusrpent said that the paper was of much interest to him,

a as

a a a

s

¥ob, 522} AT BARRY, GLAMORGANSHIRE. 489

as he had during many years past paid considerable attention to the
submerged forests and peat-beds which have been found along the
Welsh coast of the Bristol and St. George’s Channels. Some sub-
merged forests were noticed by the historian Giraldus Cambrensis
in the 12th century, at spots now constantly covered by the sea ;
and there is other evidence to show that great encroachments have
taken place in comparatively recent times. When the forests which
contained oak, alder, birch, etc. as their chief trees, grew on the
plains and in the valleys exposed to the westerly winds, it is clear
that the sea must have been at a considerable distance ; and it seems
more than probable that the Bristol Channel was then mainly a tract
of marshy plains traversed by important rivers. The trees in the
forest at Whitesand Bay, Pembrokeshire, which he examined many
years ago, had been deeply rooted in the underlying Boulder Clay,
and many antlers of the red deer, a jaw of the brown bear, and a
well-worked flint-flake were found by him in the peat-bed. Possibly
the oldest of the beds referred to by the Author might belong to
the same period, but the others appear to be of more recent date.

Mr. Coprineton said that the old beds of the river and ‘ pills’ along
the coast indicated subsidence at least as great as 55 feet. The rock-
bed of the Wye at Chepstow was 42 feet below low water, having
40 to 50 feet of mud over it containing nuts, leaves, and oak-timber.
In Milford Haven the rock-bottom of Myland Pill was 45 feet below
low water, and that of the channel of the pill at Milford Docks
deeper still, with 40 to 50 or 60 feet of mud. There were many
such sections.

The AurHor replied to Prof. Jones that he had acknowledged the
occasional invasion of the estuary by salt or brackish water, implied
by the presence of foraminifera and some of the ostracoda. At the
same time the entire absence from the estuarine beds of the marine
shells which abounded in the overlying deposits was significant.
The hypothesis of the President, that when the lowest peat was
being formed the Bristol Channel was dry land traversed by a
winding river had occurred to him also, and it was with this in mind
that he had pointed out the existence of a deep narrow channel about
2 miles south of Barry. ‘The relative levels of the peat-beds and the
sea could not be explained by mere encroachment of the latter. No
glacial deposits occurred either in the excavations or in the immediate
neighbourhood. ‘The existence of the numerous buried valleys
referred to by Mr. Codrington, and the general character of the
deposits filling them, were well known to him, They had been
explored, however, chiefly by borings, and he attached greater value
to observations made on such deposits in situ, and to specimens
collected with every precaution against the mixing of the fauna and
flora of different beds, than to the mangled débris brought up by
the boring-tool.

ae

490 MR. CLEMENT REID ON THE [Aug. 1896,

28. The Kocrxe Derosrts of Dorset. By Crement Ret, Esq.,F.L.S.,
F.G.8. (Communicated by permission of the Director-General
of H.M. Geological Survey. Read April 29th, 1896.)

THE new survey of the western end of the Hampshire Basin having
necessitated certain modifications in the geological map, it may be
useful to lay the principal results before the Society. If the
alterations were mere matters of detail, this would scarcely be
worth while; but the more accurate mapping has led to the discovery
of a sudden westerly change in the character of the Lower Bagshot
Sands, and of a well-marked overlap at their base. The mapping of
the Tertiary strata proves also that there is evidence of other periods
ot earth-movement in southern Eugland, besides those already
known,! and that we are dealing with one of those. regions where
folding affects the same area again and again.

When the Eoceuve strata are followed westward through Sussex
and Hampshire into Dorset, one finds constant local changes in the
lithological character of the deposits, though these changes seem all
to tendin the same direction. Marine beds become less conspicuous,
coarser, more estuarine, and estuarine deposits become truly fluviatile.
Thus the London Clay, which exceeds 300 feet in thickness to the
east, dwindles to less than 100 feet in Dorset, and becomes more
sandy and pebbly, though still apparently of marine origin. The
Woolwich and Reading Series—fluvio-marine at Newhaven and
Portslade, and slightly so at Lancing—becomes more fluviatile
westward, lenticular patches of subangular gravel appearing in it
west of Wareham. To what extent the Reading Series rests un-
conformably upon the Chalk is difficult to say, though overlap is
clearly recognizable in various places. The Lower Bagshot Sands
also become coarser and more purely fluviatile westward, the change
being a singularly rapid one in the neighbourhood of Dorchester.
It is to this change in the Bagshot Sands, and the conclusions to
which it leads, that attention will more especially be drawn in
the following notes.

1. Woolwich and Reading Series.

The extreme variability of these deposits makes it difficult, till
a large area has been examined, to master any general tendency in
the variations. No particular bed seems ever to be traceable more
than a short distance, the whole series being made up of a succession
of alternating masses of red-mottled clay, loam, sand, and gravel.
Plant-beds and marine strata alternate at Newhaven. At Brighton
and Portslade the deposits are still of the Woolwich or fluvio-marine

1 See Reid, ‘Pliocene Deposits of North-western Europe,’ Nature,
vol. xxxiv. (1886) p. 341; Reid & Strahan, Mem. Geol. Surv. ‘Geology of the
Isle of Wight,’ 2nd ed. 1889, chap. xiv. ; Reid, ‘Pliocene Deposits of Britain’
Mem. Geol. Surv. 1890, pp. 69, 70; Strahan, ‘On Overthrusts of Tertiary Date
in Dorset,’ Quart. Journ. Geol. Soc. vol. li. (1895) p. 549.

Vol. 52. ] EOCENE DEPOSITS OF DORSET. 491

type. At Lancing the strata are mainly of the Reading type,
consisting of alternations of red-mottled clay, loam, lignite, and sand ;
but even there certain ironstone-nodules near the base yield casts
of marine shells. From Worthing westward the southern margin
of the Hampshire Basin yields no evidence of marine conditions.

An increasing rarity of marine fossils is not the only change that
takes place when the Woolwich and Reading Series is traced west-
ward, for directly we pass from Hampshire into Dorset it is notice-
able that the sands are often coarse and full of small splinters
of flint. A few miles farther west, at Morden and at East Lulworth,
lenticular masses of coarse subangular gravel make their appearance
in the Reading Beds, and these gravels, especially at Morden, contain
a considerable percentage of Greensand chert with sponge-spicules.
This admixture of coarse sand and subangular gravel becomes still
more marked towards the western limits of the formation, and the
proportion of Greensand chert increases.

2. London Clay.

Though the London Clay thins and becomes more sandy to the
west, there is no sign of shore or estuarine conditions, and even at
its western limit it is apparently of purely marine origin. The
flint-pebbles at the base of the formation are all perfectly rounded,
as in other localities, and do not yield any evidence of beaches. The
only fossil that I have seen from the London Clay in Dorset is an
indeterminable bivalve, apparently a Cyprina or Cytherea, obtained
from the basement-bed in a boring at Wimborne. This absence of
fossils is, however, in all probability due to the sandy pervious
nature of the depusit; for though more typical London Clay with
septarian ironstone-nodules occurs, sections in unweathered material
are very scarce. Throughout the Hampshire Basin the London
Clay seems always to rest, with a sharp, slightly eroded junction, on
the Reading Series; yet there is no trace of either unconformity or
overlap, the thickness of the Reading Beds remaining approximately
the same throughout.

3. Lower Bagshot Beds.

The changes undergone by the Bagshot Sands are even more
marked than those that take place in the Lower Hocene strata.
It we follow the southern margin of the Hampshire Basin we
discover that the Sands are thin and scarcely recognizable in the
Selsey Peninsula. In the Isle of Wight, however, they expand
enormously, reaching 150 feet at the eastern end of the island and
600 feet at the western, where they contain lenticular masses of white
pipe-clay with plant-remains. The Bournemouth cliffs show a
tendency to the increase of coarse sands, containing small fragments
of black grit, lydite (or radiolarian chert), and occasionally of
(ireensand chert; splinters of flint also begin to appear. Coarse
sands of this character continue to be associated with the pipe-clays
westward to beyond Wareham. Then sets in a change like that

492 MR. CLEMENT REID ON THE [Aug. 1896,

undergone by the Reading Beds, but far more marked. The
Bagshot Sands become coarser and gravelly, unworn flints and
flint-splinters become abundant, and mixed with these is found a
quantity of subangular Greensand chert, like that occurring in the
Reading Beds. There is, however, one character which enables us
easily to distinguish between the Bagshot and Reading gravels.
The Reading gravels consist of flint and chert, with an occasional
quartz-pebble: careful search yielding nothing else except one or
two small quartzite and grit-pebbles. Bagshot gravels, on the other
hand, contain, besides flint and chert, so much quartz and hard
subangular Paleozoic rocks as to make the finer screened material
look like a Cornish beach. They yield also a certain quantity of
Purbeck marble and other Purbeck rocks, though I have been unable
to discover any trace of Portland Beds or of the Oolites below."

This gravelly condition of the Bagshot Series first becomes
conspicuous in the large pits close to Moreton railway-station, where
40 feet or so of the sands can be seen associated with seams of white
pipe-clay. In this pit one can find fragments of all the rocks which
occur in the coarser gravels farther west. It is noticeable also
that the chert-fragments found in the lower part of the pit are
often quite soft, so that they were at first mistaken for pebbles of
pipe-clay, though they soon harden on exposure to the air. A
softening of the chert-pebbles will explain the curious way in which
the fragments are sometimes dented by each other and pitted by
sand-grains, at a locality where neither earth-movement nor
pressure has ever been extreme. As I found rounded quartz-grains
half embedded in some of the flints it is possible that Chalk-flints
also can to some extent be softened in a similar way.

To the west of Moreton the Bagshot gravels rapidly become much
coarser, and as they change the Bagshot Series cuts through the
London Clay and through the Reading Beds, till it rests immediately
on the Chalk. The various outliers south and south-west of Dor-
chester all belong to the Bagshot Series, not to the Reading Beds as
formerly supposed.

A study of the composition of the Kocene gravels shows distinctly
that the rivers that brought them must have flowed from the west
or south-west. Both Reading and Bagshot gravels become coarser
and the stones more angular in that direction, and seem to occupy a
valley eroded in the Secondary strata. But of the extent of this
erosion it is difficult to obtain direct evidence, for the wide trough
south-west of Dorchester, in which several of the Eocene outliers lie,
is mainly a continuation of the syncline of the Hampshire Basin,
not an eroded hollow. A considerable amount of erosion of the
Chalk seems to have taken place before the Ridgeway and Black-
down (Hardy’s Monument) outliers were deposited ; but I am quite

1 Some of these rocks are recorded by Sir Joseph Prestwich as occurring at
Blackdown in gravel, which ‘may belong to some part of the Gle cial period,’
overlying the Hocene beds. The gravels seem to me to be of Eocene age. See
Quart. Journ. Geol. Soc. vol. xxxi. (1875) p. 41.

iq

Vol. 52.] EOCENE DEPOSITS OF DORSET. 493

unable yet to say to what extent the position of these outliers is due
to erosion as distinguished from folding. The Rey. O. Fisher states '
that when the large ballast-pit on Bincombe Down was open during
the making of the Ridgeway cutting, the Tertiary strata were seen
to be vertical. Sir Joseph Prestwich’ and Mr. Strahan,® however,
in their sections, draw the Kocene base as markedly unconformable
on the upturned Chalk. All that can now be clearly made out is
that in certain. parts of the old ballast-pit the Eocene strata are
highly inclined. It is, however, so extremely difficult to obtain
accurate dips in these deposits, owing to the occurrence of piping on
a scale which I have never seen equalled, that it is unsafe in the
present state of the section to express any confident opinion as to the
exact relation of the Bagshot strata to the Ridgeway disturbance.

Though it may be impossible readily to prove by stratigraphical
evidence the overlap of the Lower Bagshot Beds, yet the composition
of the gravels demonstrates unmistakably this discordance. One
finds on analysis that the gravels contain in the first place abundance
of Chalk-flints. Next in abundance come numerous fragments of
the Greensand chert already mentioned. The pieces are usually
subangular, and of all sizes up toa foot in diameter; so they are
not likely to have travelled far. The chert is probably derived
from the Upper Greensand.* Numerous pebbles of vein-quartz,
mostly under an inch in diameter, next attract one’s attention,
and it is not improbable that these may come from conglomeratic
seams in the Wealden strata of the immediate neighbourhood.
Fragments of Purbeck marble, sometimes silicified, are fairly common,
and are associated with cherts and grits probably also of Purbeck
age. All the rest of the material consists of subangular veined grits,
hard sandstones, quartzites, quartz, radiolarian chert, and red and
green jaspers ; in fact, of hard siliceous material such as might be
derived from the weathering of the Permian breccias of Devon.
Black grit with small quartz-veins is abundant, and, like the radio-
larian chert, suggests the Culm Measures as its source, though
probably it also is derived secondarily through the Permian breccias.
Budleigh Salterton Triassic pebbles are, however, entirely missing.

This peculiar composition of the gravels ought to give us a clue
to the amount of denudation that had then taken place, and also to
the direction in which the river flowed. The gravels of the Reading
Series, containing Chalk-flints and Greensand chert, suggest that
erosion at that period had only reached down to the Upper Green-
sand; though even this amount of erosion points to a distinct post-
Cretaceous upheaval in the neighbourhood, which tilted the Chalk
and brought Greensand within reach of the eroding agent, before the
deposition of the Reading Beds.

During, or before, the Bagshot period there seems to have
occurred another era of local disturbance, during which both

1 In lit. [since published in Geol. Mag. for June 1896].

? Quart. Journ. Geol. Soc. vol. xxxi. (1875) pl. i. fig. 2.

3 bid. vol. li. (1895) pl. xviii.

* {Chert of identical character has since been found in the Upper Greensand
near Abbotsbury.—July, 1896. ]

494 MR. CLEMENT REID ON THE (Aug. 1896,

Reading Beds and London Clay near Dorchester were so tilted as to
lead to a sharp transgression of the overlying Bagshot gravels. It
happens thus that within a distance of 3 miles the Bagshot
gravels cut through both those formations. A short distance farther
west, at Bincombe Down, the gravel has cut well into the Chalk,
and there is little doubt that within a few miles it must have over-
lapped all the Cretaceous rocks and cut into Purbeck Beds. The
reason why it is suggested that the Purbeck stones can only have
come a short distance will be seen on looking at a geological map.
Purbeck rocks might be obteined in the immediate neighbourhood
of the Bagshot gravels, on the south side of the Bincombe fault ; but
they could not have been derived from regions farther west, as in
that direction the Purbeck Beds had already been denuded and over-
lapped by the Greensand. This overlap becomes more pronounced
westward, the Greensand resting unconformably on all the Second-
ary rocks, till at Haldon there is nothing between the Greensand and
the Permian breccias. It thus comes about that no Jurassic fragments
are found in the Bagshot gravels, with the exception of Purbeck
rocks, which seem to have bordered the southern edge of the Eocene
valley. The rest of the gravel was apparently derived from the
higher part of the river-basin, where Greensand rests directly
on Permian strata, even the Budleigh Salterton pebble-bed being
overlapped and hidden.

It is noteworthy that the new evidence discovered in the western
end of the Hampshire Basin strongly supports the idea that the pipe-
clays of the Bagshot Series are derived from the weathering of the
Dartmoor Granite, and tkat the Bovey Tracey outlier, so like the
deposits around Bournemouth, is, as maintained by Mr. Starkie
Gardner, of the same age and deposited in the same basin, though
in Devon Kocene rest directly on Paleozoic rocks. Bovey Tracey
is only a short distance from Haldon, and Permian breccias, Culm
Measures, and granite rise into hills in the immediate neighbour-
hood. That district might have provided the whole of the material
in the Bagshot gravels, with the exception of the Purbeck marble.

A consideration of the evidence now brought forward shows that
besides the already-recognized earth-movements of intra-Cretaceous,
early Eocene, Miocene, and Pliocene dates, there must have been
folding during at least one other period in the same or closely ad-
joining areas. ‘The earliest, or intra-Cretaceous, folding accounts
for the marked unconformity of the Upper Cretaceous on all the
older rocks. The second disturbance, either late Cretaceous or
early Eocene, during which the Bincombe overthrust must have
commenced, caused Reading Beds to overlap the Chalk and rest on
Upper Greensand. A third disturbance allowed Bagshot Beds to
cut across the upturned edges of the London Clay, Reading Beds,
Chalk, and Greensand and reach the Purbeck and older rocks.
Finally we have the well-known Miocene folding, which threw the
whole of the Tertiaries of the Hampshire Basin into a series of
sharp undulations with an east-and-west axis, and this movement

Vol. 52.] EOCENE DEPOSITS OF DORSET. 495

seems to have continued till early Pliocene times. It would thus
appear that the district between Dorchester and Weymouth is one
of those areas of weakness which are affected again and again by
similar disturbances.

The discovery of the peculiar composition of the Eocene gravels
of Dorset has thrown an unexpected light on the source of the
material in the Pleistocene series. These gravels, from Brighton
westward into Dorset, always contain a considerable proportion of
Greensand chert of marked character, besides other foreign stones.
Of these stones a considerable number have been shown to be
glacial erratics brought by floating ice, though the glacial erratics
are entirely confined to low levels and to the area between Brighton
and Southampton Water.’ Above that level and beyond that district
the Plateau-gravels contain, however, large quantities of chert and
also of Paleozoic grits and quartz. The cherts have usually been
considered to point to derivation from a central Wealden axis. But
when it is found that the masses become larger and more abundant
westward, and that they are always associated with Paleozoic grits
that could not be derived from the Wealden area, it is evident that
they can have no connexion with the Weald, but clearly must have
been derived from Devon and Dorset. Every kind of rock found in
the Plateau-gravels of Sussex, Hampshire, and Dorset above the
level of the glacial action has now been traced to the Bagshot
gravels of Dorset, and through them to districts still farther west.

Discussion.

Mr. Srrawan said that he had had occasion to trace part of the
Tertiary base-line while mapping the Secondary rocks in South
Dorset, and that he had speculated on the age of the gravel-outliers
near Dorchester. No clue, however, was forthcoming until the
Tertiary deposits were mapped by Mr. Reid from Hampshire con-
tinuously westwards, and the overlap of the Bagshot Beds traced
step by step. It had seemed to him that there was a marked dis-
cordance in the extreme west between the Eocene and Cretaceous ;
in fact, the Chalk seemed to have been carved into hill and dale
before it was overspread by the Eocene. Moreover, in drawing a
section through Bincombe, he had found that there was not room
for the whole of the Chalk below the Tertiary outlier, and had been
obliged to show a marked overlap by the latter, as had been previously
done by Sir Joseph Prestwich. The Author’s observations tended
to confirm this conclusion. He considered that the Author had made
a seis advance towards solving an important problem in Tertiary
geology.

Mr. Monckton remarked that if pebbles from the Permian of the
West of England were found in the gravels described by the Author,
it was rather surprising that the liver-coloured quartzites of the
Triassic pebble-beds should not also occur. Heasked whether there

* See Quart. Journ, Geol. Soe. vol. xlviii. (1892) p. 344.

496 THE EOCENE DEPOSITS OF DORSET. [Aug. 1896,

was evidence founded on superposition of strata in well-sections or
otherwise to show that the gravels are really of Reading or Bagshot
age.

Mr. H. B. Woopwarp considered that the Author had proved his
contention with regard to the composition of the Bagshot gravels.
He had seen the gravel on Blackdown (Portisham), and, having
found blocks of greywether in it, he had taken it for Drift. He
was now prepared to believe anything ; but he would ask the Author
to state how he distinguished between the outliers of Bagshot gravel
and those of Drift gravel, as the question of the overlap of the
Bagshot Beds depended greatly thereon.

Mr. R. 8. Hurrizs said that there were several points of interest
in this paper, such as the continued thinning of the London Clay
towards the west, and the remarkable persistence in the thickness
of the Reading Beds in spite of their changed character. The
evidence of the Reading or Bagshot age of the gravels did not seem
quite conclusive, and it might turn out that they were later still.
The conclusion that the materials of which they and the later
gravels are composed were derived from the west was most in-
teresting, and there seemed every reason to suppose that it was
correct.

Dr. G. J. Hine also spoke, and the AutHor replied.

Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 497

29. Discovery of Mammarian Rematys in the Otp RiveR-GRAVELS
of the Derwent near Dersy. (Read April 29th, 1896.)

Part J.—By H. H. Arvorp-Bemrosz, Esq., M.A., F.G.S.

TuesE remains were discovered under the yard of the Crown Inn
at Allenton, not quite 3 miles south of Derby. In March, 1895,
Messrs. Offiler & Co. were sinking a well there for drinking-water.
When it was partly bricked in, a strong unpleasant smell was
noticed, several large bones were discovered, and the well was,
in consequence, abandoned. The water rose very rapidly, and only
twenty-one bones or fragments were taken out. These included
the lett femur of an artiodactyle, several vertebre or portions of
vertebra, and fragments of ribs. The writers obtained them from
Messrs. Offiler & Co., aud after examination decided to excavate for
the remainder. The funds necessary to defray the expenses were
readily obtained from a few local gentlemen, on condition that the
bones should be finally placed in the Borough Museum. The work
was commenced on April 8th and entrusted to Mr. Durant, builder.
During the day a hole, 8 x 6 feet, was dug through the clay, and the
water rose in it to within 6 feet of the surface. On the second day
the hole was deepened through the clay and sand to the top of the
gravel (9 feet 8 inches below the surface). One complete bone and
twelve small pieces, probably from the head, were obtained.

On the third day the clay was tunnelled on the eastern and northern
sides, the total area excavated at the bottom being about 11 by
9 feet. The tunnelling was rendered necessary because of the small
space available in that part of the yard, which was limited by
buildings on three sides and a wall on the fourth. The main diffi-
culty was to contend with the water which rose from the gravel and
caused the sides of the pit to fall in, notwithstanding the timbering.
Two large pumps were kept at work by relays of men during the
whole of the second and third days, but in spite of this most of the
work had to be done in water. Under these circumstances it was
impossible to get up the bones without breaking some ofthem. One
hundred and twenty-seven bones or fragments were found. They
were numbered in the order obtained, and their relative positions
were noted as accurately as possible. One or both of the writers
was present during the whole time, and every bucketful of sand or
gravel was carefully examined. The sand and gravel taken from
near the head were washed in asieve, but no loose teeth were found.
Most of the bones were obtained during the latter half of the third
day. No further discoveries being made, and the water gaining
rapidly upon the pumps, further work had to be abandoned.

Samples of the clay and sand were taken from the pit, and
measurements and notes of the deposits passed through were made
by both writers together.

498 MESSRS, ARNOLD-BEMROSE AND DEELEY ON [ Aug. 1896,

igs:

W007
o Oo

SSS

DSSSQqO,SSSSSS

2 feet 8 inches. QO (WI Surface-soil and clay, with a few quartzite-
SSS pebbles,

—
Lo)

Yellow sandy clay, with a few pebbles near

2 feet 7 inches, | the top; nearly free at the bottom.

4 inches. Yellow, tough clay.

Blue, tough sandy clay, with rootlets and an

1 foot 4 inches. occasional quartz-pebble.

Dark-coloured sand containing numerous
pebbles, plant-remains, bones of Hippo-
potamus, ete.

2 feet 9 inches.

—— —e — Se EE

| River-gravel (not bottomed here), with many
limestone- and chert-petbles.

The above section shows the nature of the deposits passed through.
The gravel is similar in character to that covering a large area to
the north-east, and is apparently continuous with it.

The excavations were made to a depth of 9 feet 8 inches, and the
beds of clay, sand, and pebbles were unbroken over the area exca-
vated. No clear line of demarcation separated adjoining deposits,
but the tough sandy clay passed into yellow clay above and dark
sand below. The bones were all found in the dark sand resting
immediately upon the lower gravel. A sample of the dark sand
was dried and the constituents separated in a sieve with meshes

Vol. 52.] | MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 499

zy inch in diameter. The portion retained in the sieve (with
the exception of some quartzite-pebbles, fragments of flint, and a
few very much decomposed pieces of limestone similar to those
found in the same gravel-terrace at Alvaston) was sent to Mr. Clement
Reid, F.G.S., who kindly examined it for plant-remains. Mr. Reid
reports that ‘ the plants indicate a moist meadow or swampy ground,
and a temperate climate. J can say nothing more definite, as the
species are all widely distributed. An elytron and thorax of a
beetle were found in addition to the following plants :—

Plants found with Hippopotamus.

Ranunculus aquatilis, Linn. Valeriana officinalis, Linn.

- sceleratus, Linn. Eupatorium cannabinum, Linn.

x Flammula, Linn. Leontodon autumnalis, Linn.

vs repens, Linn. Taraxacum officinale, Web.

ay bulbosus ?, Linn. Ajuga reptans, Linn.

Sardous, Crantz. Atriplex ?

Viola palustris, Linn. Eleocharis palustris, Linn.
Montia fontana, Linn. Scirpus pauciflorus, Lightf.
Rubus Ideus, Linn. Carex ?
Potentilla ? Isoetes lacustris, Linn.’

Hydrocotyle vulgaris, Linn.

Part of the sand which had passed through the ae sieve was then
sifted through others with meshes of +, inch and 54, inch, and the
various portions were examined under the microscope. It consisted
for the greater part of a quartz-sand, the larger grains of which were
well rounded, and the smaller subangular and broken, together with
flakes of white mica, some of which showed a negative bisectrix in
convergent light. In addition to these a eae small ee of
a fine dark-coloured material and fragments (j5 inch to J, inch in
diameter) of probably plant or bone occurred, or perhaps both of
these substances.

A sample of the blue sandy clay was similarly examined. It
contained a few rootlets, and consisted of broken quartz-grains and
a fine amorphous substance.

A sample of gravelly sand from the same gravel-terrace at
Alvaston was also examined. Mr. Reid was unable to find any
plant-remains in the sandy clay or in the gravelly sand.

The 127 bones and fragments obtained belong almost entirely to
the Hippopotamus, and probably to one animal.

List of Hippopotamus-bones.

Lower jaw (greater portion) with the two back molars and two canines.
Five cervical, thirteen dorsal, four lumbar, and four sacral vertebree.
Os innominatum.
Hind legs and feet:
Left femur, 21 inches long.

», tibia, 15 inches long.

,, fibula (lower portion).

» calcaneum,

» cuboid.

» metatarsal iv.

500 MESSRS, ARNOLD-BEMROSE AND DEELEY ON [Aug. 1896,

List (continued).

Right fibula (lower portion).
», caleaneum,
5» cuboid.
» metatarsal iv.
» astragalus.
Fore foot :
Left lunare.
5» scaphoid.
Portions of the 3rd or 4th right and left ribs and of other ribs, to
the number of six or seven.

The majority of the bones are complete ; others, such as the os
innominatum, were broken in course of extraction from the matrix,
but have been pieced together. As a result there are about fifty
complete or nearly complete bones. ‘They are partly mineralized,
are ina good state of preservation, and do not appear to have been
rolled or knocked about.

Since so many parts of the animal’s skeleton were found in a
small area, it 1s probable that the body was stranded in an old
channel of the river Derwent and quickly covered up by sand and
clay—not, however, before the bones had been somewhat disturbed.
The lower jaw was lying upside down, with the canines pointing
north-west, the fibula and left iv. metatarsal, right astragalus and
caleaneum were found together on the south; and the left femur,
right iv. metatarsal, some ribs, the five cervical and some dorsal
vertebre on the north. But by far the greatest number of bones,
including the os innominatum, left tibia, dorsal, lumbar, and sacral
vertebree, part of the fibula, and right and left cuboid, was found on
the east and nor‘h-east.

The large number of bones, their good state of preservation, and
their only slightly disturbed positions, point to the conclusion that
the carcass was deposited almost entire at the spot where the bones
were found. All the evidence is against the supposition that the
bones have been derived from an older deposit.

In addition to the Hippopotamus-bones were found part of the
breast-bone of an Elephas and part of the femur of a Rhinoceros.
The latter was near the head of the Hippopotumus and is more
indurated than the bones of that animal. It is also scratched and
worn. Many of the bones were taken to the Jermyn Street Museum,
and, by the kindness of Mr. E. T. Newton, F.R.S., were compared
with specimens there.

Since the above was written, Mr. Allen (who built the Inn at
‘Allenton about 18 years ago) was interviewed by the writers. He
says that some large bones were found when a well was dug and
the cellars were excavated. They were not preserved, but were
sold by the labourers and probably destroyed.

Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 501

Part IJ.—By R. M. Deetey, Esq., F.G.S.

The deposits in and beneath which the mammalian remains were
found occur on the inside edge of a gravel-terrace which covers a
large area on the right side of the Derwent Valley below Derby.
Its south-western boundary is more or less obscured by a variable
thickness of unstratified, yellow, sandy clay containing pebbles.
Masses of this pebbly deposit frequently penetrate 6 or 8 feet
into the gravel, much as does the ‘trail’ of Southern England.
At its inner edge the gravel terminates against rising ground,
composed of Keuper Marl capped in places by Boulder Clay. The
line of junction between the gravel and the Keuper commences on the
south side of the breach made in the Derwent Valley escarpment by
the Kedleston Brook. From here it skirts the lower portion of the
Royal Infirmary grounds, crosses the railway near Osmaston Road,
passes a few yards to the south-west of the section at Allenton,
and then skirts the base of Chellaston Hill until the river-escarp-
ment of the Trent, a mile north of Aston-on-Trent, is reached. Its
north-eastern boundary is a continuous and steep escarpment about
18 feet above the modern alluvial plain of the Derwent.

This escarpment, starting near the Kedleston Brook breach,
passes through the Midland Railway-station, and keeping on the
north side of the London road, passes through Alvaston, Elvaston,
and Aston, when it joins the corresponding escarpment of the
Trent Valley.

Over the whole of this area the terrace is nearly flat, and slopes
gently down the valley and towards the river. Itis drained by two
small streams, the larger of which rises near the spot where the
bones were discovered. The point where the bones were found is
indicated by a circle on the map, fig. 2 facing p. 502.

This portion of the ground I have contoured, so as to show the
exact relationship between the Boulder Clay capping the ridge, the
Derwent gravel to the N.E., and the low-level deposits of Sinfin
Moor to the S.W. As the line of demarcation between the gravel,
Keuper Marl, and Boulder Clay is more or less obscured by a sheet
of ‘ trail, the line marking the edge of the gravel is only approxi-
mately correct. The outcrops were, however, carefully followed by
means of a boring-rod. The Boulder Clay was found to rest in all
places upon Keuper Marl. It is a tough, bluish, sandy clay, with
numerous striated limestone-boulders, and an abundance of coal,
shale, gritstone, ete.

The gravel below the deposits in which the bones were found does
not, therefore, either rest upon or pass beneath the Boulder Clay, but
terminates rather abruptly against Keuper Marl.

A map published in this Journal, vol. xlii., p. 488, shows the whole
of the terrace and also the surrounding deposits.

Fig. 3 (p. 502) is a section passing through the Allenton terrace.
It commences in post-Glacial Trent Gravel, and then passes through
High-level Trent Gravel, Sinfin Moor deposits, Pennine Boulder

Clay, High-level Derwent Gravel, and
post-Glacial Derwent Gravel. An exca-
vation on Sinfin Moor showed

feet. inches.
Black peatiwsnaew nesters
Disintegrated shells
Stiff yellow clay

Shells

eeeescseceeareseerseoeensen

ONmNoOrF
Como whby

eoeseeseterescesesccesn

Excavations showing the Allenton
gravel are not very numerous. The
best now open is situated a little to the
east of Alvaston Church. The deposit
is a red sand or sandy gravel, with beds
of sandy clay containing pebbles. The
pit is close to the edge of the escarp-
ment. There is, consequently, very
little left of the ‘trail’ at this point,
denudation having been responsible for
the removal of the fine material. Near
the surface, however, the bedding is
much broken and twisted, and in places
all signs of stratification have been
obliterated (fig. 4). A thickness of 10 or
11 feet of gravel is exposed, the lower
portion only being comparatively free
from contortions. The pebbles are chiefly
quartzites, chert, cherty limestone, and
gritstone. Limestone is not found in the
clean gravel, having been dissolved by
percolating water. Even in the beds of
sandy clay the limestone has been almost
wholly dissolved, nothing remaining in
some places but a white chalky powder
and hard core. <A boring through the
gravel passed into Keuper Marl and
proved the thickness of the deposit to
be 13 feet 8 inches.

Many excavations in the town of
Derby and its suburbs have exposed
gravel. In all cases the upper portion
was seen to consist of contorted or un-
stratified yellow or red sandy clay with
pebbles, or disturbed red gravel. An
excavation for a cellar on the London
road showed great rolls of red stony
clay cutting down into the gravel to
depths of 6 feet or more.

Although limestone is not plentiful
in the gravel and sand near the edge of
the terrace, it is abundant in the gravel

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Quart. Journ. Geol. Soc. Vol. LIT.

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Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 503

near Allenton on the inside boundary : a large number of limestone-
pebbles having been found in a deep ditch south-west of Boulton.
Under the nearly impervious covering of clay at Allenton, limestone-
pebbles are numerous and fresh. Indeed, except as regards its
weathered, disturbed, and stained condition, there is no marked
difference between the terrace-gravel and the gravel of the lower
alluvia plain.

Fig. 4.—Jnterglacial river-gravel, Alvaston, near Derby.

[Height of section = 7 feet. |

I have already stated the fact that the brook which drains the
southern portion of the terrace, and debouches upon the modern
alluvial plain of the Derwent near Thurlston, rises near Allenton :
the contour-lines on the south-easterly portion of the map (fig. 2)
being deflected when they reach the upper end of the trough. The
section (fig. 3) shows this trough in the gravel filled with sand and
clay. It runs approximately from N.W. to 8.E., and was proved
to exist by several borings which entered gravel a few yards to the
north-east of the spot where the bones were found. This is con-
firmed by Mr. Allen, who informed us that wells sunk to the N.E.
do not enter the bone-bed, but pass directly into the lower gravel,
while wells to the 8.W. enter red marl.

South-east of Allenton the soft trough-deposits have been denuded,
and a depression has been formed along which the stream runs. It
seems to have been a deserted loop of the Derwent, formed when
the river ran at the level of the terrace.

In favour of the view that the dark sand and fine blue clay are
of the same age as the terrace, the following additional considerations
may be urged. In the first place, the limestone-pekbles found
beneath the trough-deposits are in a better state of preservation
than they are near the edge of the terrace, and appear to have been

Q.J.G.8. No. 207. 2M

504 MESSKS, ARNOLD-BEMROSE AND DEELEY oN ([ Aug. 1896,

preserved by the bed of nearly impervious clay which has covered
them from the time they were first laid down. Secondly, the yellow
upper clay with pebbles strongly resembles the ‘ trail’ covering the
terrace and Keuper at other points. However, it was only exposed
for a few feet when the deep excavation was made, consequently
its horizontal extension and variation, as it passes from Keuper to
gravel, was not traced by open sections. Thirdly, such deposits as
fill the trough are not being formed at the present time on the
upper terraces. They are in fact being rapidly denuded from them,
and are now only to be seen at points distant from the edge of the
escarpment. The ridge separating Sinfin Moor from the gravel-
terrace 1s also very low and narrow, and there is no stream running
over the terrace which could have excavated the trough and then
allowed it to be filled again. On the other hand, it might be urged
that the trough was formed by the river immediately after the
gravel was contorted, and that the river deserted the Allenton side
of the valley soon after. This view, however, is scarcely so well in
agreement with the facts.

At about the same level as the Allenton gravel-terrace a tongue
of red gravel runs up the valley on the south side of Kedleston
Brook. It is a red, indurated, sandy gravel which shows few signs
of stratification, but here and there contains small lenticular masses
of sand. The stones are sometimes large, generally well rounded,
and lie at all angles in the red sandy matrix. They are mostly
quartzites, but Keuper sandstone and flints also occur. The gravel
is about 11 feet thick and rests upon Keuper.

The upper few feet of the Kedleston Valley deposit, where it
meets the Keuper on the south-western boundary, shades off into
red or yellow clay with pebbles. An excavation near Stretton’s
Brewery, close to the edge of the gravel, exposed clay with stones
and sand, varying in thickness from 10 to 11 feet. It rested
upon contorted and broken, not redeposited Keuper marl. At this
point the whole deposit is ‘ trail’ and ‘ underplight’ rather than river
or brook gravel, and indicates the action of disturbing forces which
do not now act in the valley.

I have dealt at some length with the Allenton terrace (and its
Kedleston extension) because the remarks made concerning it will
apply, with little alteration, to several other extensive deposits of
gravel and sand. Although we have called it a high-level terrace
it is by no means the highest of its class, for such gravels are to be
seen at higher levels along the course of the Trent as well as the
Derwent. In some instances they reach a height of 70 or 80 feet
above the alluvial plain of the river. In all cases they show con-
torted upper surfaces or intruded rolls of marl (Quart. Journ. Geol.
Soe. vol. xlii. 1886, p. 467). They have already been described at
some length in this Journal. Suffice it to say, therefore, that they
are portions of alluvial river-plains which mark former levels at
which the river ran, and which have escaped subsequent denuding

‘Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 505

action by the rivers. The highest are, consequently the oldest,
and the lowest the most recent.

The Allenton gravel forms one of the lowest of the upper series
of terraces, and, since it was spread out by the river, the Derwent
has deepened its valley from 15 to 20 feet, and by excavating
horizontally as well as vertically, and leaving behind it a bed of
gravel and brick-earth, has formed a broad low-level alluvial plain.

The question of the relationship of the river-gravels to the
surrounding deposits merits more detailed notice, for there are
considerable masses of silty boulder-clay in their immediate
wicinity.

The elevated land to the south and south-west of the Allenton
terrace is capped by two varieties of boulder-clay and associated
gravel and sand. The oldest deposit, the Pennine Boulder Clay, is
a stiff, blue, silty’clay containing numerous well-striated and
polished rock-fragments from the Pennine Chain. These boulders
may have, in part at least, come down the Derwent and Wye
valleys, and in part by way of Staffordshire, Cheshire, and Lan-
cashire from the Yorkshire Fells. Flints are absent except in the
“trail. A mass of this boulder-clay spreads as an irregular
patch over the low ridge separating the Allenton terrace from the
depression of Sinfin Moor, as shown in the map (fig. 2). As
already pointed out, it rests upon Keuper Marl. The same boulder-
clay is exposed in an open section at Sheldon Wharf, a little farther
south. Fora description of this section, see Quart. Journ. Geol. Soc.
vol. xlii. (1886) p. 449. It here passes beneath another and newer
boulder-clay, namely, the Great Chalky Boulder Clay.

At Spondon, on the opposite side of the valley, the hill is covered
by another mass of Pennine Boulder Clay, which reaches a thick-
ness of more than 60 feet.

The Great Chalky Boulder Clay covers the greater part of Chel-
Jaston Hill to the south of Allenton, where it attains a great thick-
ness. Unlike the Pennine Boulder Clay, the Chalky Boulder Clay

contains an abundance of rock-débris only to be found in situ to the

east of the Pennine Chain. The boulder-clay is capped by a thick
bed of clean, stratified, current-bedded sand at a height 256 feet

above Ordnance-datum, or 130 feet above the alluvial pl-.in of the

Derwent. The sand is about 17 feet thick, and does net resemble
river-gravel,

Boulder-clays of both kinds have been found capping the high
grounds and river-escarpments of the Trent and its tributaries. At
some points they come down to levels within a few feet of the flood-
level of the Trent. They were deposited in the pre-Glacial river-
valleys which they filled to a depth of at least 100 feet ; and when
the rivers again commenced to flow, on the disappearance of the
ice, their first task was to clear away the Glacial deposits. The
high-level terraces were formed while this was taking place.
Indeed the pebbles and boulders which they contain are, in many
instances, only such as could have been derived from the boulder-

2m 2

506 MESSRS. ARNOLD-BEMROSE AND DEELEY oN [ Aug. 1896,

clays of the area. The patches of boulder-clay now remaining are
merely portions, which denudation has spared, of great sheets which
once nearly filled the lower grounds of the Trent Basin.

The alluvial plain through which the Trent, and the lower
reaches of many of its tributaries, run, consists of a thick bed of
gravel, for the most part covered by a layer of brick-earth. Sec-
tions have been opened out in it at many points.

An excavation, for a gasometer, to the east of the Midland Rail-
way Station, Derby, passed through brick-earth and then gravel and
sand. Limestone and gritstone were plentiful. A few flints were
seen. The deposit was regularly stratified, and false-bedded, and:
quite undisturbed, nothing in the nature of ‘ trail’ being seen at or
below the surface.

The ballast-pit (now full of water and known as Trent Lake)
exposed a fine section of modern Trent gravel. Here also the
‘trail’ was absent, the upper surface being quite undisturbed and
the gravel, sand, and brick-earth regularly stratified from the brick--
earth to the bottom of the gravel.

At Colwick, near Nottingham, another pit exposed these modern:
gravels. Here the brick-earth was about 2 feet thick. The surface
showed no trace whatever of disturbance, and the gravel and sand
were well stratified and false-bedded.

In all cases where the newer deposits have been exposed in
section, ‘ trail’ and ‘underplight’ were quite absent, the surface
portions being quite free from contortions. The low-level gravels
of course show signs of root-penetration, the sand and pebbles being.
bleached or discoloured by the action of organic acids, etc., but this
cannot be confounded with ‘trail,’ neither can the subsidences-
resulting from the action of underground denudation.

Certain physical features of the valleys also deserve notice.

Wherever the modern alluvial plain is bounded by a high-level
gravel-terrace, or other resisting rock, the boundary-line between it
and the alluvium is marked by a steep escarpment. Such a con-
tinuous low cliff may be traced through Derby, Alvaston, Elvaston,.
Aston-upon-Trent, Weston-upon-Trent, and thence along the north-
ern side of the Trent Valley as far as Egginton. It then turns up the
Dove Valley. It may also be traced up the Trent Valley beyond
Burton.

On the northern side of the Derwent Valley the escarpment is
continuous between Borrowash and Long Eaton. Passing down
the Trent it commences again at Beeston, and on the right bank of
the river it may be traced from Gamston in the direction of Newark.

Where streams enter the main valley, the terraces are breached,
and the brooks run in V-shaped hollows.

These escarpments separate the disturbed from the undisturbed
deposits, the high-level formations only showing the ‘ trail.’

At one time, no doubt, the two upper terraces at Weston-on-Trent
(Quart. Journ. Geol. Soc. vol. xlii. 1886, p. 469) faced the river
with steep slopes also, but their edges have in some way been

ware
, ee
B4

‘Vol. 52.] MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS,

507

smoothed off, and it is difficult to resist the conclusion that the
agent which contorted the gravels hereabouts (produced the ‘ under-
plight ’)—fig. 5—also obliterated the terraced aspect of the ground.

Fig. 5.—High-level river-gravel, Weston-on-Trent.

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[Height of section = 5 feet. |

The excavation of the Sinfin Moor area is also a difficulty. It
is an almost perfectly flat plain, about 1 square mile in area,
covered by more than 8 feet of shell-marl, peat, and fine clay. The
surface is at about the same level as the alluvial plain of the
Derwent (see fig. 3, p. 502), and only about 4 or 5 feet above the
low-level plain of the Trent. It cannot have been excavated by
running water, for it was once a lake which had been drained
by the deepening of the Trent Valley. Nor does it show any
sign of having been produced by earth-movements. The Allenton
terrace, for instance, does not appear to have been locally de-
pressed, although the gravel approaches to within ? mile of the
hollow, and is only separated from it by a low ridge. On its
southern side Sinfin Moor is separated by a much higher ridge (also
capped by gravel running at definite levels) from the Trent Valley.
The moor waters drain into the Trent through a narrow short valley
between Chellaston and Swarkstone. The depression could not well
have been in existence when the Allenton terrace-gravels were being
formed, for if it had the lake would have been a deep one, and no
shigh-level terraces or deltaic deposits have been found to support

5 Bit aien a
ISECANE ES

pbs

—=-
_-_ —_—_

508 . MESSRS. ARNOLD-BEMROSE AND DEELEY on [ Aug. 1896,

the view. Nor could it have existed when the high-level gravel on:
the northern escarpment of the Trent, shown in section (fig. 3,
p- 502), was being deposited ; indeed, it has clearly been excavated
at a comparatively recent date, and was once a shallow lake, which
has since been drained by the deepening of the Trent Valley. It
seems to have been formed by a glacier at the same time as the
‘trail,’ or, which is much less likely, by the removal of a.
soluble bed in the Keuper Mar! below.

We are now in a position to discuss the age of the bone-bearing:
deposits.

Although in no case have we found any of the high-level gravels:
resting upon either the Pennine or the Chalky Boulder Clay, from
the positions which the gravels occupy on the sides of the valleys.
and the presence in them of flint from the Boulder Clays, it may be
safely concluded that all the river-gravels were deposited at a sub-
sequent date. It only remains, therefore, to show how they are
related to the gravels, etc., of the lower plain, and to decide whether.
they are of Interglacial or post-Glacial age.

It is generally conceded that glaciers have never reached those:
portions of England that lie to the south of the Thames Basin..
There we have no true boulder-clays. But even thus far south
deposits are to be found which it is difficult to account for, except on
the supposition that the climate was at one time very cold. When
such surface-deposits were being formed, other portions of England:
were being glaciated, and, therefore, such deposits belong to a —
British Glacial Period. Any period of cold which was sufficiently —
severe to cause glaciers to appear in Britain we may call a ‘ glacial
period,’ and any period intermediate between the two glacial periods.
an ‘interglacial period.’ Whether it is wise or the contrary to
retain a classification connoting a physical change in the condi-
tions. under which the deposits were formed is open to argument,
but such considerations need not influence us in settling the relative:
ages of the particular deposits with which we are dealing. Conse-.
quently, whether the ‘underplight’ and trail be due to an agent
owing its existence to a change of climate, or to some other cause,
we may with confidence assert that they are now being denuded
from most if not all the areas in this country on which they were
at one time formed, and are typical of a particular epoch or epochs:
of the Pleistocene Period.

Just as it has been suggested that the formation of certain rubbly.
deposits, etc., which have been formed in the South of England must:
be attributed to the action of frost, heavy masses of ice or snow and
of floods on a frozen ground, so I would attribute the formation of
similar deposits in the Midlands to similar agencies. But some of
the surface-phenomena presented by the gravels, etc., which have
been described above can, I think, only be explained on the as-
sumption that, at a comparatively recent period, and after the rivers
had excavated their valleys to a depth of within 15 or 20 feet
of their present levels, an ice-lobe from the basin of the Irish.Sea

Vol. 52.| MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. 509

passed down the Trent Valley for some distance to the east of
Nottingham.

In the South of England and in certain areas on the Continent,
the flexures of the ‘underplight’ seem in all cases to bear a very
close relationship to the slopes upon which they occur. According
to Mr. Spurrell, it is ‘ the result of a steady movement, a flow or push
in certain directions in accordance with the slopes on the surface of
the land: the amount of slope determining the direction being often
very slight.’ In the area of the Trent Basin under consideration
the phenomena which we are discussing do not, in a large number
of cases, bear out the contention that the flexures may result
from the flow of surface-deposits down slopes, for they occur on
extensive flat areas, and the trend of the furrows and ridges is
such, in the majority of instances, as would indicate a movement
from the west or thereabouts rather than down the adjoining hill-
sides.

We must, I think, admit that ‘trail’ and ‘underplight’ may
have been formed under slightly different conditions in different
districts, and that the conditions which obtain or have obtained
in each district must be deduced from the appearance of the local
deposits.

Otherwise, how are we to explain the fact that indurated masses of
gravel such as those at Allenton, Weston, Beeston, Lenton, and Gam-
ston, and also other surface-deposits, have been forcibly puckered and
bent to depths of from 8 to 12 feet from the surface? Not on sloping
surfaces, be it remembered, but on approximately flat areas of con-
siderable extent. That such surface-features are not now being
produced may be seen from all the sections of post-Glacial gravel,
loam, soil, etc., which have been described. But it is not only the
gravels which have been contorted and disturbed in this way. The
surface of the older rocks, where it can take and preserve such
features, is affected. Sometimes the contortions or waves terminate
abruptly at the surface-soil as though they were the remnants of a
thicker deposit, the upper portions of which have been removed.
That the contortions are not due, in some instances at any rate, to
the slipping of the surface-layers by the direct action of gravity
is proved by the fact that they often occur on level ground. Indeed,
upon the steeper slopes of the area deposits of ‘ trail’ and contorted
surfaces are generally not to be found, for denudation has there
acted so energetically that all traces of such surface-action have
disappeared.

We are, therefore, constrained to admit, it seems to me, that the
upper terraces covered by the ‘ trail’ or showing disturbed surfaces
are of Interglacial age. That the Allenton terrace is of Inter-
glacial age was stated in a paper read before this Society in 1886,
and all subsequent work has tended to confirm me in this opinion.
The discovery of Hippopotamus, Rhinoceros, and Elephas in the
gravel supports this view rather than militates against it.

510 MAMMALIAN REMAINS IN DERWENT RIVER-GRAVELS. [ Aug. 1896,

Discussion.

The Presipent congratulated the Authors on their remarkable
find, and on the splendid specimens exhibited by them. The mode
of preservation of the fossil remains reminded one of that of the
Endsleigh Street mammoth-remains, and in both cases it was no
doubt attributable to the covering of the deposits by a clayey layer.
Indeed, as a whole, the conditions much resembled those of the
Thames Valley : there, as in the Derwent Valley, were plateau-
gravels and low-level gravels. He enquired whether certain de-
posits marked on the section exhibited were not originally one sheet
of gravel, rather than several distinct terraces. If Mr. Deeley’s
view of the Interglacial age of the fossiliferous deposits was correct,
we had here another point of resemblance with the Thames Valley
deposits.

Mr. Rerp congratulated the Authors, and hoped that they would
continue to search the deposit for further evidence of the climatic
conditions. He doubted whether surface-contertion in gravel was
sufficient evidence of glacial action or of an Arctic climate.

Mr. E. T. Newron also spoke.

Mr. Dretery, who replied on behalf of Mr. Arnold-Bemrose and
himself, thanked the Fellows who took part in the discussion for the
considerate way in which they had criticized some of the points
raised in the paper. At so late an hour he thought that it was
impossible to discuss the question of the origin of the ‘trail’; he
therefore contented himself with remarking that, just as Mr. Reid
had held with regard to the Bagshot Sands, it was necessary to
examine the ground mile by mile, and map and compare the deposits
with each other, so in the case of the ‘ underplight’ it was necessary
to take into account its local peculiarities in order to form a correct
conclusion as to the agent which produced it. In reply to the
President’s question concerning the relationship between the various
high-level terraces of the Trent and Derwent, a section through the
gravels of Weston-on-Trent was instanced. Here there are three
high-level terraces, the escarpments of the two upper ones seeming
to have been obliterated by the agent which produced the flexures
of the ‘underplight.’ In the operation of excavating the valley the
erosive action of the stream exerted itself both horizontally and
vertically, and the river always left behind it a sheet of gravel.
Each terrace is consequently a fragment, which has escaped denu-
dation, of the gravel-plain formed when the river ran at that
particular level, the highest being the oldest, and the lowest the
most modern: the connecting gravel-areas which separated the
terraces having been denuded as the rivers wandered from side to
side of their valleys.

‘Vol. 52.| LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. 511

30. The Linevta-Fiacs and Iexexovus Rocks of the NutenBourHooD
of Dotertty. By Parr Laks, Esq., M.A., F.G.S., and 8. H.
Reynotps, Esq., M.A., F.G.8. (Read May 27th, 1896.)

[Prats XXIV.—Map.]

ConTENTS.
Page
Pee Ne trr ACOTA vite oe rare cn fic hcemanak tn Sac pon falls age apna rnes ee 511
Pee McaOrMMUIOM OF UNE ECE | uses. cckseraenveepscrensdssocece 512
MED: Ceolomigal SUrMCtMFE ! ..ioccdebdsdceasdeccdessedaereeceses 512
EY. Phe Stantitied Boeke iis ip. pvceeh Muisds ss vipcnscieces sao. 513
(a) The Slopes of Mynydd Gader.
(6) West of the Dolgelly Fault.
(c) Upper Volcanic Series.
VY. The Intrusive Diabases and their Relations to the
BUCAMM EMEC PI SUGS ee canes. bot escbe <b cet acne naoenim ceva BIT
VI. Age of the Intrusive Rocks and of the Faults ...... 521
Py MU GAPIABIGIE Sieber tne ak deka beh dee Sewn ducdieae optician dela 521

I. Inrropucrion.

Tue magnificent section displayed in the precipitous northern face
of Cader Idris has attracted the attention of many geologists, and
has proved so seductive that the lower-lying country to the north
has been almost neglected. It is with the latter that we are
concerned. Here the Lingula-Flags are well developed, and are
associated with contemporaneous volcanic rocks and with remark-
able intrusive masses of diabase.

But little has yet been published concerning these rocks. Belt’
in his classical paper upon the Lingula-Flags has dealt with the
general sequence in the district, and refers to several localities in
the neighbourhood of Dolgelly. Cole and Jennings* have examined
the rocks immediately south of the area covered by our map, and
they were led to believe that the volcanic eruptions of this region
began at least as early as the Tremadoc period; but, as they remark,
the point requires further investigation. We are able to justify
their belief, for we have discovered a well-defined band of andesitic
lava in the Lingula-Flags themselves.’

Several references to the region will also be found in the
Geological Survey Memoir on North Wales*; and the account of
the Lingula-Flags in the Paleontological Appendix is in this
respect of particular interest.

1 Belt, ‘On the “ Lingula-Flags”’ or ‘‘ Ffestiniog Group” of the Dolgelly
District,’ Geol. Mag. 1867, pp. 493-495, 536-543; ibid. 1868, pp. 5-11 & pl. ii.

2 Cole & Jennings, ‘The Northern Slopes of Cader Idris,’ Quart. Journ.
G eol. Soe. vol. xlv. (1889) pp. 422-439.

3 [It should be mentioned that Messrs. Salter and Hicks have already
recorded contemporaneous trap from the Lingu/a-Flags (Quart. Journ. Geol.
Soe. vol. xx. 1864, p. 241); and that Dr. Hicks finds voleanic material in the
Menevian and even at the boundary between the Caerfai and Solva beds (Geol.
Mag. 1894, p. 405).—July, 1896.]

+ Ramsay, ‘The Geology of North Wales,’ Mem. Geol. Surv. vol. iii. 2nd ed.
1881.

512 MESSRS. P. LAKE AND 8. H. REYNOLDS ON THE [Aug. 1896,.

II, Description oF THE AREA.

The area with which this paper deals lies south and west of
Dolgelly, between the Arthog road and the hill called Mynydd
Gader, which stands in front of the precipices of Cader Idris.

The town of Dolgelly stands in the valley of the Wnion, a short
distance above the point where that river enters the broad and
picturesque estuary of the Mawddach. South of the river the
ground rises generally, but not uniformly, to the west of the Cader
Idris ridge. From the eastern end of the town a deep and rather
narrow valley, cut by the Afon Aran, runs in a southerly direction
into the rising ground; and from Pandy’r-odyn, a short distance
west of Dolgelly, another stream has carved a second valley which
stretches away to the S.W. along a line of fault, which we shall call
the Dolgelly fault.

Between these two valleys, immediately south of the town, the
ground rises steeply to a broad and rocky plateau occupied by a mass
of diabase ; and then sinks slightly to a lower and more level plain,
which stretches across the map from east to west, and on which is
built the house called Rhydwen. In the eastern part of this plain
the Nant Ceunant cuts for some distance a deep and narrow gorge
along a line of fault; and from this fault the ground again slopes
up, with some inequalities, to the foot of the diabase crags of
Mynydd Gader.

West of the Dolgelly fault, the contour of the ground, so far as
our map extends, is nearly the same as it is on the east. South of
the Arthog road there is a steep rise which gradually becomes
gentler as we approach the top of a great rounded mass of diabase ;
and on the southern side of the diabase the surface falls to a tract
of marshy land—the continuation of the plain of Rhydwen.

In the N.W. corner of the map, the diabase is narrow and makes.
only a low and unimportant ridge, while the highest ground is.
formed by the Lengula-Flags north of it.

III. Grotoeicat STRUCTURE.

The area examined is divided into four parts by three nearly
parallel faults running from S8.W. to N.E., the most important of
which lies in the valley of Llyn Gwernan and Pandy’r-odyn.

Another fault, south of Dolgelly, follows the general direction of
the lower part of Nant Ceunant, and brings the diabase on the
north against the Middle Zingula-beds on the south. Along the
line of this fault there is a zone of rock crushed into a kind of stiff
green clay. It is visible in the bed of the stream itself, but is still
better shown in the cliff which forms the right bank of the Afon.
Aran just above its junction with the Nant Ceunant. Hl

The third fault coincides for a short distance with the stream that
flows east of the farm called Derwas, in the north-western corner
of the map. It brings the black slates and the lava-band of
Bryn-y-gwin woods into contact with the Middle Lingula-Slates of
Derwas and Gwern-y-barcud, the beds on both sides striking nearly
east and west. This we may call the Derwas fault.

[To face Pp. aS.

Pandyr odyn

\Z

Ly :
<a

OF cae anit

SARS.

AX ARA

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Vr Rr A

We AT ye

Ny
y
SWANS

eae

Quart. Journ. Geol. Soc. Vol, LIT, Pl. XXIV.

[Yo face p. 512.

Te

Si...

‘gw ddioxs

GEOLOGICAL MAP
OF THE

NEIGHBOURHOOD o DOLGELLY. — vecniaaySvaen

Scale: 3 zches = 1 mile. Vv

Alluvinm, Drift &c (Solid Geology concealed)
Li) Upser lolcanic Series

GG Trematic Beds

ZA. Upper Dolgelly Beds

|. {Paes (Arugite-andesite)| Lingula-Flags is
(MIN eewe Dolgelly Beds\ (Middle & Upper) v

. M.
Ffestiniog Beds Ay Se yvTan-y-ahder(, ¥
VOY Iz Ve

Intrusive Diabase
vy Gilfachwydd_ vy
om= Faults : as

ve

o

x

Vol. 52.| LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. 513;

Lastly, we have some reason to believe that a fault runs nearly
from north to south just outside our map on the east; but our
evidence is not complete, and in any case the fault does not affect
the area actually described.

In the north-western corner of the map the dip is southerly..
The Middle Lingula-beds are well exposed and are overlain, just
along the northern margin of the diabase, by a band of darker
slates belonging to Belt’s ‘ Dolgelly Group.’

The Derwas fault clearly has its downthrow on the south-eastern
side, and brings the black slates and lava-band of the Upper
Lingula-beds into line with the Middle Zingula-beds on its north-
western side. But it does not affect the inclination of the beds,.
for the lie of the lava in the Bryn-y-gwin woods shows that the
general dip is still southerly. This is maintained even on the other
side of the great diabase mass, for near Graig we find slates and
ashy beds, the latter showing a dip of about 32° due S.

East of the Dolgelly fault, and north of Nant Ceunant, most of
the surface is occupied by diabase ; but the ashes and other stratified
deposits which form the band stretching across towards the Afon.
Aran still keep the southerly dip.

South of the Nant Ceunant fault, however, there seems to be a
marked change in the general strike. On the northern slopes of
Mynydd Gader the band of lava in the Upper Lxngula-beds runs.
about W.N.W.—E.S.E., indicating (since the surface slopes down
from south to north) that the beds dip towards the south-west.
In the Middle Lingula-beds, however, north-east of this lava-band,
there is considerable variation, and south-east of Brynmawr the
dip is due west.

IV. Tue SrratiFrep Rocks.
(a) The Slopes of Mynydd Gader.

Nant Ceunant.—The fullest and clearest section of the sedi-
mentary strata in this district is to be seen in Nant Ceunant, a
tributary of the Afon Aran.

About 250 yards N.E. of Tan-y-fedw the diabase, which forms
most of the bed of the stream up to this point, gives place to bluish
slates, interstratified with hard gritty bands. These continue up
the stream for some distance, and contain Lingulella Davisii in
abundance. They belong to Belt’s ‘ Ffestiniog Group.’

Gradually the slates become darker and darker in colour, and
cease to yield Lingulella ; but a solitary fragment of a trilobite was
discovered. A narrow band of volcanic ash or lava (not shown in
the map) occurs ; and then follow more dark slates extending to a
distance of 7 mile south of Tan-y-fedw, where they are succeeded
by the thicker bed of andesitic lava shown in the map.

This lava is followed by a series of very black fissile slates with a
black streak, which continue without much change up to the crags
of Mynydd Gader. But at one point we came across a small band
of ashy-looking rock, which appears to strike in quite a different

d14 MESSRS. P, LAKE AND 8. H. REYNOLDS ON THE [ Aug. 1896,

direction from the beds below. It was, however, visible only in the
stream. Probably better exposure would disclose other small
complications; but the general structure of the slope is clear.

Bryn-rhug.—The chief bed of lava just mentioned can be clearly
traced over the fields both S8.E. to the diabase of Mynydd Gader, and
N.W. to the stream at Bryn-rhug ; and it affords a good datum-line
for correlating the section in Nant Ceunant with that at Bryn-rhug.

At Bryn-rhug the lava forms the top of a waterfall of considerable
height, and the beds immediately below it have been quarried, so
that the conditions are more favourable for examination than in
Nant Ceunant. The beds in the quarry are dark hard slates, con-
taining numerous fossils referable to the following species :—Orthis
lenticularis, Dalm., Agnostus, Leptoplastus, and Parabolina spinulosa,
Wahl. (one specimen). They belong to Belt’s ‘ Dolgelly Group.’

Above the lava we get the same black fissile slates as in Nant
Ceunant.

Tan-y-gader.— When we reach the next stream on the west, the
one which flows past Tan-y-gader, the lava has sunk down into the
level alluvial plain, and the first rocks which are visible, close to the
farm, are the black fissile slates. Slaty beds continue in the stream
up to the diabase ; but they gradually become paler in colour and
firmer in texture. A fragment of a trilobite was found some
distance above Tan-y-gader; and near one of the small tributaries
close to the diabase, Lingulella lepis, Salt., was discovered, not
actually in situ, but in blocks which clearly belonged to the
neighbouring rocks. This is a Tremadoc form.

Gilfachwydd, etc.—Similar slates occupy most of the lower slopes
of Mynydd Gader west of this stream, and a little south of
Gilfachwydd they have yielded Dictyograptus flabelliformis, showing
that the higher beds of this slaty series belong to the Tremadoc.

In the upper part of one of the streams between Tan-y-gader and
Gilfachwydd, the slates are succeeded by a band of rhyolite, which
may be traced westward as far as the small diabase-mass south of
Gilfachwydd.

Similarly in the stream which flows past Gilfachwydd, the slates
‘which form most of its bed, and which near the farm have yielded
Dictyograptus, are succeeded on the south by a mass of rhyolitic
davas and ashes.

General sequence.—The general sequence of the beds, therefore,
on the northern slopes of Mynydd Gader, from the Nant Ceunant
westward, is as follows (in ascending order) :—

Davisti and passing up into

ened WenseinroG: adie: slates with grit-bands, containing Lingulella
aoe (Dark slates, with Orthis lenticularis, Leptoplastus,
(MippLe | ete. (at Bryn-rhug).

AnD UppEr).

Doucetiy. { Andesitic lava.
| Black fissile pyritous slates, which appear to pass
|. up into
Dark grey slates, with Lingulella lepis, Dictyo-
TREMADOC. graptus flabelliformis.
Rhyolitic lava.

—_

Vol. 52.] LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. O15

It may be remarked here that Belt attaches much importance
to the black streak characteristic of his ‘ Upper Dolgelly Group.’
Generally speaking, the slates above the andesitic lava, and no
others, possess this peculiarity ; but we have not been able to draw
a definite line between them and the somewhat paler-coloured
beds above.

East of Nant Ceunant.—We commenced our description with the
Nant Ceunant because here the general succession is most clearly
shown; and we have described the character of the rocks west
of that stream. It is now necessary to give some account of those
which lie farther east.

The lava-band may be followed from Nant Cetinant with very
little interruption until it reaches the diabase of Mynydd Gader ;
and for the greater part of this distance it is well exposed, forming
the crest of a spur which juts out from the main ridge of Mynydd
Gader. The black slates below the lava are also very clearly seen ;
and in the streams which run down from Mynydd Gader, east of
Nant Ceunant, they are underlain by slaty and gritty beds which
in many places yield Lingulella Davisw in abundance, and clearly
belong to Belt’s ‘Ffestiniog Group.’ These beds become more
gritty lower down.

Similar beds occupy the greater part of the space between the
black slates and the Nant Ceunant fault, and are visible at
intervals over the whole of this area. They are particularly well
exposed, and Zingulella is particularly abundant, in the hill which
lies west of Brynmawr. They also occur in the wood between
Tan-y-fedw and Bryn-rhug.

Another point in connexion with the Mynydd Gader slopes
requires notice. The band of lava which lies above the Dictyo-
graptus-beds in the west follows the base of the diabase as far as
the head of the Bryn-rhug stream; and a mass of similar rock
occurs even as far east as Nant Ceunant. It is clear, however, that
in its eastern part this lava does not strike in the same direction as
the beds below, but lies across their edges. We believe that it is
not here in its natural position, but has been dragged into its
present situation by the diabase.

(6) West of the Dolgelly Fault.

Bryn-y-gwin Woods.—A sequence similar to that in Nant Ceunant,
but by no means so complete, is developed along the northern
border of the great mass of diabase west of the Dolgelly fault. The
stream which flows past Pandy’r-odyn runs nearly along the line
of the fault, and on its left hank the same beds are exposed as in
the woods farther west. The right bank, on the other hand, is
formed, in part at least, by the ashy rocks which occur in the hill
on the east.

Leaving the latter out of consideration for the present, we find
dark bluish slates forming the bed of the stream at Pandy’r-odyn.
These pass up gradually into black shaly slates which extend

516 MESSRS. P. LAKE AND 8S. H. REYNOLDS ON THE [Aug. 1896,

almost continuously up to Bron-y-gader. The only fossil which we
discovered was a fragment of a trilobite; but Belt states that he
found ‘Dictyonema fenestrata, Salt.,’ below Bron-y-gader.

Above Bron-y-gader these black slates are succeeded by a band
of lava; and beyond this no further exposures are visible in the
stream until we reach the diabase.

But the band of lava is seen again in the hill on the west, in the
path near Bryn-y-gwin farm ; and farther west still it is exposed for
a considerable distance in the woods of Bryn-y-gwin. Everywhere
it is underlain by black slates similar to those in the stream, and
overlain by a second band of black slates, in which we discovered
Obolella Sabrine, Call., at two localities. The upper part of the
second band close to the diabase sometimes contains fragments of
ash.

The band of lava which is shown upon the map is, like that in
Nant Ceunant, an andesite; and, as in Nant Ceunant, we have
slight indications of the existence of a smaller volcanic band below
it. About 350 yards above Pandy’r-odyn a small ashy looking
band crosses the stream; and a somewhat similar band is rather
badly exposed at the farm of Bryn-y-gwin.

Although in the absence of better palzeontological evidence, there
is no absolute proof that the beds in this area are the same as those
in Nant Ceunant, yet the correspondence between the two sequences
is so close as to leave little room for doubt; and we are justified
in considering the Bryn-y-gwin lava to be the continuation of that
in Nant Ceunant.

West of the Derwas fault.—West of the little valley where the
lava and black slates of the Bryn-y-gwin woods abruptly cease, the
predominant rocks are bluish slates with bands of grit. Hast of
Derwas they dip 8.E. or 8.S.E., while near Gwern-y-barcud they
dip due south. Close to the latter farm we found Lingulella
Davisit.

These beds are succeeded, as in Nant Ceunant, by darker coloured
slates, which lie along the northern margin of the diabase. In one
of the small woods a little west of Maes-angharad they yielded
Parabolina spinulosa in abundance, and one specimen which looks
like Arionellus.

The slates with Lingulella Davisit are clearly the equivalents of
those near Tan-y-fedw, and the beds with Parabolina spinulosa
probably lie at a somewhat lower horizon than the fossiliferous
slates of Bryn-rhug. The latter are close to the lava-band, and
seem to be separated from the LZ. Davisii-beds by a greater thick-

ness of deposit.
(c) Upper Volcanic Series.

On the slopes of Mynydd Gader the beds which contain Lingu-
lella lepis and Dictyograpius flabelliformis are succeeded, as already
shown, by a band of rhyolite; and towards the western end of the
hill this is followed by a considerable area of volcanic rock which
we have not yet examined in detail.

‘Vol. 52.] | LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. 517

On the southern side of the diabase-mass in the north of the
map, west of the Dolgelly fault, a similar series of volcanic rocks is
exposed, together with a certain amount of slate. They dip towards
the south, and appear to be the continuation of the sequence of
which the lower members are exposed on the northern side of
the diabase. The thickness of the black slate visible above the
lava-band in the Bryn-y-gwin woods is very much less than above
the equivalent band on Mynydd Gader; but probably the upper
beds of the slates are concealed beneath the diabase.

A series of ashes and tuffs of rhyolitic character is exposed in
the road and copses north of Rhydwen; and a belt of ashes,
agglomerates, etc. runs from east to west between the two patches
of diabase immediately south of Dolgelly. The general dip in this
belt is southerly. Similar rocks form the bed of the Afon Aran
near Dolgelly and part of the eastern bank of the stream above
Pandy’r-odyn.

It is only on Mynydd Gader that the age of these volcanic beds has
been proved by paleontological evidence. There they undoubtedly
lie above beds which contain Dictyograptus flabelliformis, and
therefore they cannot be older than Tremadoc.

But we cannot be far wrong in assigning a similar or later age
to the other patches, for nowhere in this district have we found
any evidence of so great a series of ashes and lavas among the beds
below the Tremadoc.

It may be remarked here that in Aber Gwynant, a stream which
lies beyond the western boundary of our map, there is a sequence
not unlike that on the slopes of Mynydd Gader; and here again
it is not till we pass the Dictyograptus-slates that we reach any
extensive series of volcanic rocks.

So far as we have examined with the microscope the rocks here
spoken of as the Upper Volcanic Series, we find that they are
rhyolitic lavas, ashes, and tuffs; while the band of lava in the
LIrngula-beds is an andesite.

VY. Tue Intrusive Drapases! AND THEIR RELATIONS TO THE
STRATIFIED DEposIts.

The most important areas of diabase in the district examined are
the Mynydd Gader mass, and the large patches which occupy so
much space in the northern half of the map. The latter, as will
be shown, are probably parts of a single mass.

Besides these there are a number of smaller masses or sheets, the
positions of which are sufficiently indicated upon the map.

The Dolgelly mass.—There can be no doubt that the more southerly
of the two patches of diabase which lie immediately south of Dolgelly
is continuous across the Dolgelly fault with the great mass which

1 [Some account of the petrological characters of these diabases will be found
in Messrs. Cole and Jennings’s paper (Quart. Journ. Geol. Soc. vol. xly. 1889,
p. 431). We hope, at some future date, to deal more fully with the petrology
of the igneous rocks to which we have referred.)

518 MESSRS. P. LAKE AND 8, H. REYNOLDS ON THE [ Aug. 1896,

stretches west towards Maes-angharad. This being so, the most-
striking feature of the whole, as shown upon the map, is the
contraction of the outcrop where the streams east and west of the
town have cut their valleys deep down into the igneous mass. On
the high ground the width of the diabase is great, and the boundaries.
follow the contour-lines, reducing, however, the prominence of the
curves. Where, on the other hand, the surface is lower, as in the
valleys of the streams, the outcrop is narrow, and the boundaries
are straight and independent of the contours. These facts indicate
that at the level of the higher ground the diabase spreads out into
a broad mass, the under surface of which, near its boundaries, is-
gently inclined ; while at the level to which the valleys have been
carved it forms a comparatively narrow vertical-sided dyke. The
transverse section in fact is like a section of a mushroom.

Near Maes-angharad the mass narrows again ; and this no doubt
is partly owing to the lower level of the ground in that neighbour-
hood. But it may also be due in part to the Derwas fault. The
downthrow of this is on its south-eastern side, and if it faults the
diabase as well as the sedimentary deposits, its effect will be to
bring to the surface on its north-western side a lower and therefore
narrower part of the mass—to expose, in fact, the stalk instead of
the head of the mushroom.

Close to Dolgelly there is a smaller patch of diabase which forms.
the slopes immediately above the town, and this is perhaps a part
of the northern expansion of the great mass, from which, however,
it has been separated by denudation. The southern boundary of
this patch is a curve, the convexity of which points up the slope on
which the rock occurs. The surface, therefore, which separates the
igneous rock from the sedimentary deposits near it, is not yertical,
but dips down hill. Moreover, the bed of the Afon Aran and
the right bank of the stream above Pandy’r-odyn do not show
diabase, but ash in the lower parts of their courses. These streams
have cut through the diabase, and have exposed the beds below,.
and the diabase is therefore a sheet upon the hillside, no doubt
with an irregular base.

In its mushroom-like form the great mass of diabase whick
stretches across the Dolgelly fault is not unlike a laccolite, but in
its relations to the beds below it offers certain striking peculiarities..
Its northern boundary west of the fault runs nearly parallel to
the lava-band already described, so that here the mass appears to
rest upon the surface of the bed below it. But along its southern
boundary, whereas the surface of separation between the diabase
and the stratified beds below it is shown by the map to be nearly
horizontal, the stratified beds themselves dip at a fairly high angle
to the south. ‘The diabase, therefore, no longer rests upon the
surface of the beds, but upon their edges. Moreover, as we have
already seen, a considerable thickness of slates which should occur
between the lava of the Bryn-y-gwin Wood and the ashes of Graig
is invisible. These slates are probably concealed below the diabase.

On the eastern side of the fault the beds of ash, ete., which le

Vol. 52.] LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. 519

between the two patches of diabase, dip to the south, while the
northern diabase-patch dips towards the north. It will be noticed
that the northern boundary of the southern patch follows the
contour-lines, reducing, however, the sharpness of all the curves;
and this shows that the base of this mass dips towards the south,.
following, perhaps, as on the western side of the fault, the dip of
the beds below. The southern boundary, however, follows the
contour-lines very closely, and the diabase near this boundary must
therefore be horizontal. ?

The form which the mass has assumed is shown in the sections.
(figs. 1 & 2) on p. 520. The diabase has been intruded, with a
tendency to follow the bedding up to a certain height, at which it
begins to spread out horizontally. It is clear that the plane along
which it has spread must have been a plane of weakness; but it is
not, as in most laccolites, a bedding-plane. Thrust-planes being out
of the question in this case, the most feasible explanation is that
the plane was one of unconformity; that the Lingula-Flags and
other rocks of this district were overlain unconformably by a later
series, that the diabases were subsequently intruded and spread along
this unconformity, and that the higher beds have since been removed
by denudation. But as we have no trace of the higher beds, this
explanation becomes nothing more than a suggestion.

Mynydd Gader mass. —The form of the Mynydd Gader diabase
is similar in some respects; but here our observations are not yet
completed, and we have followed only the northern boundary. If
this boundary, as shown upon the map (Pl. XXIV.), be examined,
it will be noticed that it is not straight but wavy, and although
unfortunately the contour-lines are not drawn up to this height, it is
clear that the curves are due to the form of thesurface. For where
a stream crosses the boundary and has cut a little valley, there the
boundary recedes towards the south, while between the streams it
bulges out towards the north. In the field ié is found that the floors
of the valleys are formed (where they are deep enough) by the lavas
and other stratified beds which underlie the diabase, while the walls
are formed of the diabase itself. The surface of separation between
the diabase and the other beds slopes down towards the north.
The Mynydd Gader diabase, therefore, along its northern boundary,
forms a sheet rather than a vertical intrusion.

At the western extremity of the mass, however, these relations
are not preserved. The small elliptical projection at the western
end is a hill of diabase almost completely surrounded by hills of
nearly equal height which are formed of stratified deposits. The
diabase here forms a kind of plug or neck.

The patch of diabase which lies 8.E. of Llyn Gwernan appears to
be a sheet dipping towards the north, and doubtless is a continu-
ation of the Mynydd Gader mass.

Concerning the smaller masses but little need be said: all of
them show a tendency to run parallel to the strike of the sedimentary
deposits, but nevertheless are probably intrusive. The small patches
near Brynmawr and Bryn-rhug are very much decomposed.

Q.J.G.8. No. 207. 2N

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Vol. 52.] | LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. 521

VI. Ace or THE InTRUSIVE Rocks AND OF THE FAULTS,

The three chief faults shown upon the map run nearly, but not
quite, parallel to one another, but they are not of precisely the
same age. The Nant Ceunant fault is clearly posterior in date
to the intrusion of the diabase; and, as we have seen, this is
probably true of the Derwas fault also. The Dolgelly fault, on the
other hand, has little influence upon the intrusive mass, although
its effect upon the stratified deposits is very marked. There is,
‘however, evidence that a small amount of movement took place
along the plane of this fault after the intrusion of the diabase.
The sections drawn on the two sides of the fault (figs. 1 & 2) show
that the diabase spreads at different levels. North-west of the
fault the lateral expansion of the diabase takes place at a height
of +400 feet above the sea, and south-east of the fault at a height
of 450 feet. This seems to indicate a downthrow of 50 feet on the
north-western side since the intrusion of the diabase; while the
downthrow of the stratified deposits (which took place before the
intrusion) is on the south-eastern side of the fault.

The actual age of the Dolgelly fault is not itself determinable,
but it runs parallel with the great Bala fault which, on the other
‘side of Cader Idris, lies in the valley of Tal-y-llyn. The Bala
fault is Upper Carboniferous or post-Carboniferous in date, for in
its extension to the north-east it frequently faults the Carboniferous
Limestone and Millstone Grit. Some geologists may be disposed to
infer that the Dolgelly fault is of the same age as the Bala fault,
and that the diabase is therefore post-Carboniferous in date. But
this must still remain open to doubt.

If the plane along which the diabase near Dolgelly has spread in
laccolitic fashion is one of unconformity, the unconformity must be
newer than the Dolgelly fault, for the lateral expansion of the
diabase takes place at nearly the same level on the two sides of
the fault—if anything even at a higher level on the downthrow
side. If, therefore, the plane is one of unconformity, either the
Dolgelly fault must be pre-Carboniferous, or the unconformity must
‘be a newer one than that at the base of the Carboniferous.

VII. Concrustons.

In conclusion we believe we have shown that: (1) outflows of
-andesitic lava occurred in this region as early as the period of the
Upper Lingula-Flags; (2) at some subsequent date intrusions of
diabase took place, which show a tendency to spread out more or less
horizontally along a certain plane, perhaps a plane of unconformity ;
(3) the diabase in some cases, as it flowed along, dragged with it great
masses of the underlying rock; (4) faulting took place both before
and after the intrusion of the diabase; and in one case there seems
to have been movement along the plane of the fault in one direction
before the intrusion, and in the opposite direction after the

intrusion.
2n2

522 LINGULA-FLAGS AND IGNEOUS ROCKS OF DOLGELLY. [Aug. 1896,

Priate XXIV.

Geological Sketch-map of the Neighbourhood of Dolgelly, on the
scale of 3 inches to the mile.

Discusston.

The Presrpent said that it was interesting to find that andesitic
lavas occurred in the Dolgelly Beds. Acid lavas were frequently
found in the Lingula-Flags of North and South Wales, and beds
mainly composed of volcanic ash occurred at the top of the Menevian
group at St. David’s and near Maentwrog. He thought that most.
of the diabase-intrusions in the area were of Ordovician age.

Mr. W. W. Warts expressed the pleasure he felt that the Authors
were not content with proving that the diabase-masses were of
laccolitic character, though they had done that conclusively, but had
gone beyond and used the existence of the laccolite to draw further
conclusions as to the structure of the area. He reminded the Society
that he had described laccolites of similar diabase which occurred in
the Shelve district, resting unconformably on Ordovician strata and
covered by Silurian rocks which were altered at the contact. It
could be proved in Shropshire and Montgomeryshire that the
diabases had nothing in common with Carboniferous and post-
Carboniferous intrusions, and he therefore thought that the Authors’
suggestion with regard to the Dolgelly masses was founded on too
slender evidence.

Mr. Laxez, in reply, said that the Authors were by no means
wedded to the hypothesis that the diabases were of post-Car-
boniferous age. The evidence derived from the faults is very
uncertain. fParallel faults are not necessarily of the same age;
and even in the case of a single fault, movement may take place at
different periods. The absence of olivine tends rather to suggest
that the intrusions may be pre-Carboniferous; and the question
must still remain an open one.

Vol. 52.] GkoLoGy OF THE NEIGHBOURHOOD OF CARMARTHEN. 523

31. On the Guotocy of the Nurcusournoop of CarmarTHEN. By
Miss Margaret C. Crosrieztp and Miss Eruet G, Sxnar.
(Communicated by J. HE. Marr, Esq., M.A., F.R.S., Sec. G.S.
Read April 15th, 1896.)

[Puares XXV. & XXVI.]

ConTENTS.

Page
‘I. Introduction and Bibliography ..........scseseeeeee 523
PEL PMVRIGSL SELUGHUNE cc. leocickads daceederswedidarcucccesesss 524

III. The Succession and Detailed Description of the
SEAS syne at daewoo oe eons deena ess ecdiascners 525
IV. Comparison with the Deposits of other Areas ... 531
V. Description of some new Species of Trilobites ... 535
NDEs © rine sto) 22 9.5 geass nisin ws <a, Alad odae tessa e chee 539

I. Iyrropuction AND BIBLIOGRAPHY.

‘Tur area described in this communication has Carmarthen for its
-centre, and lies approximately within a 4-mile radius of that town, as
‘indicated in the accompanying sketch-map (Pl. XXV.). Our object
in examining this district was to trace the continuation of the com-
plex anticline which was discovered by the late Mr. T. Roberts,
-about 10 miles west of Carmarthen. In the map illustrating his
ypaper’ the anticline is shown to be narrowing rapidly in the
neighbourhood of Mydrim, the Didymograptus-beds seem to wrap
‘round the older Yetragraptus series, and apparently the anticline
“ds dying out.

An examination of the beds round Carmarthen has enabled us to
-establish this conclusion, and to show that in our own district we
-have a new anticline, the northern limb of which continues in the
‘same direction as that of the anticline farther wesc, but with a core
onsisting of older rocks, which we correlate with the Tremadoc
Slates. The southern limb of the new anticline is buried under
‘(Old Red Sandstone (which here encroaches farther north than at
St. Clears), but in the northern limb we have a regularly ascending
series from Tremadoc Slates to Dicranograptus-shales. To the east
this regular succession of beds is disturbed by the presence of an
extensive series of alternating grits and sandstones, with some
shales, the last containing Bala fossils. The beds in question abut
on those of Arenig age, but whether their appearance in this locality
is due to faulting or to an unconformity we cannot at present deter-
mine, owing to the nature of the ground and the exceedingly complex
character of the foldings. The clue to the relations of these beds
would doubtless be discovered by an examination of the area lying
to the east.

* Roberts, T., ‘Notes on the Geology of the District West of Caermarthen,’
Quart. Journ. Geol, Soe, vol, xlix. (1893) p. 166.

524 - MISS CROSFIELD AND MISS SKEATON THE _— [Aug. 1896,.

The literature relating to this district is as follows :—

Davipson, T. ‘British Brachiopoda,’ vol. iii. pp. 232, 233, pl. xxxiii. figs. 17, 21.-
MEMOIRS OF THE GEOLOGICAL SURVEY, vol. i. (1846) p. 25 & vol. ii. (1848) pt. i.
pp. 262 et seqq.

Mourcuison,R. I. ‘The Silurian System’ (1839), pt. ii. pp. 355, 358, 361, 664 &
- 720, pl. xxv. figs. 3a, 36 & pl. xxxiv. fig. 9.
—. ‘Siluria, 5th ed. (1872) pp. 55-58.

Satter, J. W. ‘A Monograph of the British Trilobites’ (1864), p. 178, pl. xviii.
fig. 11 & pl. xxv. fig. 4.

Symonps, W.S. ‘Records of the Rocks’ (1872), pp. 99, 100, 125.

The district was geologically surveyed by Sir H. De la Beche:
and Mr. W. EH. Logan in 1845, with additional Silurian lines by
Mr. W. T. Aveline in 1855—56, and is shown on Sheet 41.

Il. Paysicat SrRuctuRE.

The physical structure of the country is sufficiently marked to:
demand a slight description. The most striking features are the
isolated hills with their steep sides, abrupt squarish outlines, and-
flat tops sloping westward, as, for example, Llangunnor and:
Trevaughan Hills, and Bryn Merthyn. These hills are part of the
system of roughly parallel ridges which cross the country from.
north-east to south-west. The practically uniform level of the hill-
tops, which range from 400 to 500 feet in height, and the presence:
of the common westerly slope suggest that we have here an ancient.
plain of marine denudation. The axes of the hills are formed of
bedded grits, sandstones, or slates in a vertical position, while the:
valleys consist of the softer shales. This structure is primarily due’
to the earth-movements to which this district, like the rest of
South Wales, has been subjected, but the processes of denudation.
have emphasized it and laid it bare. ‘The streams flowing east and:
west have worn away the softer shales, forming valleys with gently
sloping sides; the dip-valleys, on the other hand, are strikingly
deep and narrow, and the streams have cut out steep and rocky
gorges. The river Towy enters the district from the east, but
makes a sharp southward bend near the town, where it is joined by
its tributary the Gwili; the united streams then take a remarkably
sinuous course, and have covered the broad level valley with a thick
deposit of alluvium. It seems probable that the river-bed marks a
line of considerable geological disturbance. The district is bounded
on the south by the long low range of Old Red Sandstone hills, and
the undulating slopes of these present a marked contrast to the
often abrupt outlines of the hills formed of the older rocks. The:
earth-movements which have affected this district are so compli-
cated that it would be useless to attempt to give any exact idea of
their effects within the limits of this paper. They have resulted in
the formation of innumerable folds and faults, the latter of which
are most noticeable in the north just outside our district. The
distribution of the folds makes it possible roughly to distinguish two.
great periods of earth-movement. The first period gave rise to an.
immense number of small anticlines and synclines, the axes of which.
run north and south. In consequence of this folding the beds,

[To face p. 524.

————- REFERENCE =

Old Red Sandstone,

Bala.

Rs Dicranograptus Shales.
Didymograptus Murchisoni Shales.
== Didymograptus Bifidus Shales.

== Arenig.

x S SS Seen \ ¥ = 7remadoc Slates.

SN SS Si” Alluvium.

: oe Halts.

*... Fossil Localities.

Ti]

Pen-lan’

1 Mile

Quart. Journ. Geol. Soc. Vol. LIT. Pl. XXY.

GEOLOGICAL Aer
SKETCH-MAP Meme!
of the neighbourhood of Newchurch

CARMARTHEN .

.

[To face p. 524.

2 ff ay, I 7 ij

Yj

YA

vv)

tations

=

—REFERENCE ——
Old Red Sandstone,

Dicranograpius Shales.
Didymograpius Murchisont Shaies,
=== Didymorraptus Bifidus Shales,
Arenig.
Tremadoc States.
Alluwinm,
a Faults.

+...Fossil Localities,

Furlongs8 7 6 5 4 3.2 110 Yo 1 Mile

=

=

a is

—
—

hel
a

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 525

frequently crop out along north-and-south lines for a short distance,
as is well seen in Mr. Roberts’s district to the west. After this
universal crumpling of the crust had taken place a second period of
folding on a still grander scale set in. This was evidently part of
that great movement which produced the Condrozian ridge, and all
the beds of this part of Wales were affected by it. In the end a
great series of huge anticlines and synclines were formed with their
axes running east and west, so that the second movement was at
right angles to the first. A single limb of one of these complex
anticlines forms the subject of the present paper. The uniform
direction (N. to N.W.) of the cleavage throughout the district shows
that it was produced either simultaneously with this last folding or
at a later period.

Ill. Tae Succusston anD DEtaItep DxscRIPTION oF THE BEDs.

1. Tremadoc Slates.

About 24 miles south-west of Carmarthen, exposed in the banks
of the Nant-y-Glasdwr, are fine-grained blue-grey shales, which
weather a rich yellow or brown, and are often iridescent. Inter-
calated with the shales are occasional bands of micaceous sandstones.
The beds dip 68° due south, and pass immediately under the Old
Red Sandstone. They have yielded Ogygia marginata, n. sp.,
Parabolinella, n. sp., Peltura punctata, n. sp., Orthis, and Orthoceras.
Peltura punctata occurs very abundantly, Ogygia marginata
much less frequently, and only one specimen of Parabolinella was
obtained. ;

Confirmatory Sections.

A little west of the Nant-y-Glasdwr, in the Nant Pibwr at Cwm
Ffrwd, the shales are more gritty, and assume the character of
mudstones. Alternating with them are some hard grey grit-bands.
The junction with the Old Red Sandstone is seen in the bed of the
stream, and near it the shales are considerably disturbed, the dip
varying repeatedly in the space of a few yards; elsewhere the dip
is south. We found here Ogygia marginata, Peltura punctata,
Orthoceras sericeum, Salt., and Modiolopsis. The Ogygia occurs
much more plentifully here than in the Nant-y-Glasdwr, but no
perfect specimens were obtained. On the western side of the
River Towy near Cwrt Hir Farm, in a hole by the roadside, we found
fragments of Hrinnys, sp., Peltwra punctata, and Orthis; and a
little east of this, in Cwrt Hir carriage-drive, where there is an
alternating series of coarse grits and shales, we found in the shales
Ogygua margimata and a species of Orthis.

2. Arenig Beds.

A typical section of these beds is seen just below Glan Pibwr
Cottage, in the narrow lane which leads down to the stream. They
consist of fine-grained, dark, bluish-grey mudstones, finely bedded,
and weathering in iridescent shades of brown and red. The rock

526 - MISS CROSFIELD AND MISS SKEAT ON THE [Aug. 1896,

greatly resembles the Tremadoc Slates, but, on the whole, is harder,
and not interstratified with grits or sandstones. The shales in the
lane dip south, and thus pass under the older Tremadoc Beds. We
find this inversion of the normal succession in all the strata on the
southern side of what we may term the Mount Pleasant and Ystrad
ridge. The fossils obtained here were mainly trilobites, but a few
specimens of Phyllograptus, sp., were also found. The list is as.
follows :—Ampyzx, sp., Ogygia marginata, Ctenodonta, Phyllograptus,
sp., ef. angustifolius, Hall. At Pen-y-banc, about } mile eastward,
the same species of Ogygia and a Lingula were obtained.

Confirmatory Sections.

The small stream above Pwntan House, west of the river Towy,
has cut its way through similar mudstones of a rather lighter colour.
In this rock the bedding-planes are tolerably far apart, and the
intervening rock breaks with difficulty. The fossils are abundant
and well preserved, but consist entirely of Ogygia marginata and of
a few specimens of Ctenodonta. East of the Towy similar mud-
stones may be seen in the brook which passes under the road
close to Carmarthen Junction, but only a few distorted portions of
Ogygia marginata were obtained.

At Allt Pen-y-coed, 2 miles nearly due east of Carmarthen
Junction, the mudstones are exposed in a fine deep gorge; the beds
are not very fossiliferous, but yielded a head and tail of Ogygua, sp.,
ef, Selwynit, Salt.

In the banks of the Nant-y-Caws, on the same strike, is a great
thickness of shales lithologically similar to those of Glan Pibwr, but
containing, both in the upper and lower parts of the gorge, bands
of grit and some conglomerates. As the dip varies from 35° N., not
tar from the bridge in the lower part, to 55° S. 30° E. at the water-
fall, where the junction with the Old Red Sandstone occurs, we have
probably here a small subsidiary anticline. These shales are very
unfossiliferous, and only yielded Orthoceras sericeum and Conularia.
We have placed these beds provisionally with the Arenig Series, but
whether they do not belong rather to the Tremadoc Slates is open
to question.

Lying to the north of the beds which we have just described
are others ot similar lithological and paleontological characters,
differing only in the fact that they contain in addition Calymene
parvifrons, var. Murchisont, Salt.

The chief localities where the beds containing Calymene crop out
are (i.) the Roman Road.—This exposure extends along both sides
of the deep lane of this name in the Pensarn district of Carmarthen.
The beds are shaly throughout, but vary in character in different
parts of the road. In the hard, rather flaggy beds, about halfway
up the lane many fossils were found in a very fragmentary con-
dition, this being partly due to the fact that the bedding is almost
at right angles to the cleavage. Higher up the road the shales are
hopeless for purposes of search, being crushed and weathered to
such an extent that they break always into long billet-shaped frag-

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 527

ments, without any clear face. This appearance is very character-
istic of the beds whenever they occur in a weathered condition.
The fossils obtained were Bellerophon, Ampyx, Calymene parvi-
frons?, Salt., C. parvifrons, var. Murchisoni, Salt., C. Tristani?,
Brongn., distorted fragments of Asaphid trilobites.

(ii.) Swansea Road Streams.—From the sloping ground which
‘bounds the southern side of Swansea Road two small streams flow
northwards to join the Towy. In the lower part of one of these
streams we have the D. bifidus-shales, but higher up and apparently
dipping under these are mudstones which closely resemble those of
Nant Pwntan in colour and hardness. We found here Calymene
parvifrons, var. Murchisoni, Salt., Ogygia marginata, Orthoceras, and
a small Asaphus, sp., Salter; an exposure in the second streamlet
yielded a Calymene.

In the banks of the steep lane leading to Cilwaunydd Farm were
-weathered shales containing Bellerophon, Calymene parvifrons, var.
Murchisoni, Salt., and Ogygia marginata.

Totally distinct from these mudstones, and without a fossil in
ommon with them, are the shales of Hafod-wen spring on the
western side of the River Towy. These beds contain a graptolite
fauna of Arenig age, but lithologically they resemble the Llanvirn
Beds to be next described. We obtained here Didymograptus
nitidus, Hall, D. ? constrictus, Hall, D. ? Murchisoni, Beck, Dictyo-
graptus, sp., Aiglina binodosa, and ostracoda.

3. Didymograptus bifidus-beds (Lianvirn).

These beds consist in some parts of shales alone, in others we
have alternating bands of light-grey shales and grey grits, weathering
yellow. The grits, which generally are jointed, and often veined
with quartz, vary in thickness from a few inches to several] feet ;
the shales occur in bands of 6 inches or less. The alternating
grit- and shale-bands form a well-marked ridge of hills extending
for a considerable distance along the southern side of the Pembroke
and Tenby Railway. The beds are almost vertical, but have a general
northerly dip on the northern side. Five quarries are cut out on the
hillsides, those of Ystrad, Llanllwch, Wernddu, Nant-yr-hebog, and
Pen Plas. In the last-named a thicker series of shales is seen Just
outside the quarry, dipping over the grit-beds, and here Phacops
llanvirnensis, Hicks, was found. At Wernddu we obtained Didy-
mograptus indentus, Hall; near Llanllwch and in Ystrad quarry
D. bifidus, Hall. North and south of this ridge the beds consist of
shales only; these are of a light-grey colour, fairly soft and well
cleaved. South of the ridge, at Ystrad Isaf and Hafod-wen lane,
we found Didymograptus bifidus, Hall, D. indentus, Hall, and Diplo-
graptus dentatus, Brongn. North of the railway in Trebersed
stream a crushed graptolite of the D. patulus-group and a fragment
of an eye of Aiylina were obtained ; at Castell-y-gaer a portion of a
Didymograptus, sp., and of an eye of Ayglina; farther east, near
‘Trevaughan Hill, we found Didymograptus indentus, Hall, and
Diplograptus dentatus, Brongn.

528 MISS CROSFIELD AND MISS SKEAT ON THE [ Aug. 1896,.

The beds also occur on the eastern side of the Towy, but the grit-
bands do not form here such a prominent feature as on the western
side. Inthe small quarry near the beginning of the Swansea Road,.
after crossing the river near Carmarthen, the beds are bent com-
pletely over, and form a small subsidiary anticline, the axis of which
is at right angles to the general strike of the series in the Ystrad
ridge ; lithologically, the beds are exactly similar to those already
described. The shales which overlie the grits may be seen in the
road-cutting for about 4 mile; they are dark grey or nearly black,.
and much contorted. In the quarry and along the road we found
Climacograptus celatus, Lapw., CO. confertus, Lapw., Dendrograptus,
sp., cf. flecuosus, Hall, Didymograptus bifidus, Hall, D. indentus,
Hall, D. Murchisoni, Beck, Lingula, and Siphonotreta micula. In
the small stream above the road we found Didymograptus bifidus,
Hall, and Ampyz, sp. he

At Cwarebach and Lower Henalt we have apparently an isolated
patch of beds of the same age faulted against Dicranograptus-shales.
The slates are fine-grained, bluish grey, striped with a lighter grey,
and well cleaved; they yielded Dictyograptus, sp., vel Callograptus,,
sp., cf. Salteri, Hall, and Climacograptus, sp., cf. confertus, Lapw.

A little south of Cwm Farm, near the town of Abergwili, are
several small quarries containing hard grey shales, gritty shales, and

striped flags. Here Acidaspis Buchii, Barr.,’ and Ampy.x, sp., were
obtained.

TasLz oF Fossiis FRom THE Didymograptus bifidus-SHALES.

: =
o | cool
Se is | el
Me] fe 3|. |.) ane
slslSlals|.|/S\3/3| jaz
BI ICTS ol|2) Piola] las
SIS (Else lal slal 2/3 e
SIS/8/8/Slalalelo|2/sa
Sjaln|S po ola 2 2 5 i
MAA la Sia alola
Didymograptus bifidus, Hall ............... ++ = Pa (ea ficou See eg ees os)/2c 5) * |
TRACES! WAAML), .ciiicda ck soncthewecteen salees fea % ]..c] Spee ee * |
MC CHISONG: NSCCK: oes veouxsece doses eraloce|scelaee| ee] +«:| cnc] seateee bene *
patulus group .......... Soecosg se sade Be eeilsicel| ail iwad|t % leablere spice
Diplograptus dentatus, Brongn. ...........- =| (ae oe ae ae Regal * <a
Climacograptus confertus, Lapw. ......... peli oe| ses }oe~|=>s1 +«0| saa] eee cn
CENPLUSH MAD © LA: 50.5 iodaahdetene & 34) Res Ce ee .o-{oe-|oes}oeele culeee neem
Dendrograptus, sp., cf. fleauosus, Hall ...|...|...]...|-+ ws2| es eed tet aoe) ane x |
PAU eU AB DEM cr. a Bids) fe Cha uhosne seuignaeniehicien ssabapaesiese <.:|002l see oee| aealegem mm
BUI WOIUEL, ISDS ats i'n cn cram sie che fa esiamedenrs Sep Sc |ES2 ERS pes Bes Bee % | Fe oncl ome ae
ACHASHIS SUCHE, ATT. |)... sc <gincsaenspendin eel eaten oleae vea|sos [eee |ona)| seat tein
Phacops llanvirnensis, Hicks .............--|+0+|-+-[---[eee | aloo laeeteee be |
MET Ut ats SER Re Si a d.le eng Sees spemeddanteelaes|e<)ieslsacl ord] ...4 ee eee ee *
ISUMOUGUTCLOTUICUL || an ckaahashanceek sucess Gal ser) ace) is|xaalsen| «.5| Saeleasl ene x

1 Kindly named by Mr. Philip Lake, F.G.S8.

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN, 529

4. Didymograptus Murchisoni-shales.

The outcrop of this series serves as a datum-line throughout the
district, owing to the fact that the fossils are characteristic and
abundant. The beds sweep across the country in a straight line
from Felin-wen on the east to beyond Nant-y-ci on the west. From
this point westward the outcrop takes a southerly bend, owing to:
the closing in of the anticline, and exposures occur south of Melin
Ricket as described by the late Mr. Roberts. The general dip ot
the beds is magnetic north, at a greater or lesser angle with that
of the cleavage. No actual junction with the higher beds is seen
except in Pistyll-y-gwion quarry, where a yellow sandy series
overlies the shales. The sporadic appearance of this sandstone, and
the fact that we have here the higher beds of the Didymograptus
Murchisoni-zone, render it admissible to suppose that the sandy
rock is a local development of Llandeilo Limestone, otherwise
absent throughout the district. Just north of the Plough and
Harrow Inn higher beds also occur. No certain boundary-line can
at present be drawn between these beds and the underlying bifidus-
shales, as fossils are so exceedingly rare in the upper part of the
latter.

An extensive exposure of the Didymograptus Murchisoni-beds is
seen in the large quarry behind the Plough and Harrow Inn.
They consist of dark-grey shales, with lighter stripes of more sandy
material at close intervals. These stripes show the direction of the
bedding, which is at an angle with that of the cleavage. The beds.
contained Didymograptus Murchisoni, Beck, and Siphonotreta micula.

Confirmatory Sections.

These beds are so well known elsewhere that we need only
mention the chief exposures. Proceeding from the west eastward,
we have :—

(1) The small quarry marked on the 6-inch map as Nant-y-ci
sandpit ; the purplish slates contained Didymograptus Murchisoni,.
Beck, and Climacograptus confertus, Lapw.

(11) Pistyll-y-gwion quarry must be specially mentioned, on
account of the overlying sandy series. ‘The sandstone was somewhat
coarse-grained and very ferruginous, and in it we found Orthis
testudinaria, Dalman. The shales yielded Didymograptus Murchi-
sont, Beck, Climacograptus confertus, Lapw., Lingula, and Asaphus
tyrannus, Murch.

(iii) In Penlan old quarry and on Penlanffés Hill the same
shales are seen. In the old filled-up quarries on the hill some
specimens of Diplograptus foliaceus, Murch., were also found,
owing to the fact that we have here a junction with the higher
beds. At Cwm-oernant Nurseries specimens of Didymograptus
Murchisoni, Beck, were obtained.

In the Abergwili district to the north-east of the map we have
three principal exposures. At Castell-pigyn are dark finely-splitting
slates alternating with harder flaggy beds. At Felin-wen the

230 MISS CROSFIELD AND MISS SKEAT ON THE [ Aug. 1896,

‘shales are lighter in colour, brittle, and extremely fissile: here the
fossils are most plentiful. We obtained Didymograptus Murchison,
Beck, Orthis testudinaria, Dalman, Lingula, and Orthoceras. Near
‘the top of Merlin’s Hill is a small quarry of the same shales, which
ae much weathered, and the fossils are not found on the cleavage-
faces.

5. Llandeilo Limestone.

There is no Llandeilo Limestone in the district, but, as already
suggested, this formation may be represented by the gritty and
sandy flags, which are found at the northern limit of the Didymo-
-graptus Murchison-shales. In these beds we found <Asaphus
tyrannus, Murch., and Orthis striatula, Dalman; but we have not
attempted to separate them from the lower ones. The limestone
that is used for agricultural purposes is brought from a distance,
and is mainly of Carboniferous age.

6. Dicranograptus-shales.

These beds are dark blue or black in colour, soft and well
cleaved. They are seen to dip over the Didymograptus Murchisoni-
‘shales, but the actual junction with the lower beds has not been
determined. Fossils are rare except in occasional bands, and can
‘tbe obtained only in a fragmentary condition, as the rocks are
generally cleaved at an angle with the bedding. ‘The shales are
‘best seen on the Cardigan Road, and are exposed for about 4 mile
from Cwarebach on the south to near Pantau on the north, where
they dip under a great series of hard, unfossiliferous, silvery-grey
flags. The fossils obtained from this exposure were Climacograptus
bicornis, Hall, and Diplograptus, sp.

Oonfirmatory Sections.

The beds may be traced in several sections westward. At Cwm-
du-Mawr and Allt Llyn Teg the beds are black and sometimes very
carbonaceous. They yielded Diplograptus foliaceus, Murch., and
D. dentatus, Brongn. At Felin Fach quarry and in the lane near
the Plough and Harrow Inn, where the rock closely resembles that
of Cwm-du-Mawr, the same fossils occur. Near Glan-yr-Afon in
the same road, but a mile to the north, Diplograptus foliaceus,
Murch., was found. Between these last-named exposures we have
a series of unfossiliferous, soft, pale-grey satiny shales cropping
out, which is considerably folded, and of the age of which we are
ignorant.

In a quarry near Tan-yr-allt Farm, on the western slope of
Llangunnor Hill, are pale-grey slates, weathering brown, inter-
stratified with hard micaceous striped slates of a gritty texture.
‘The beds are very barren, but yielded one specimen of Dicrano-
graptus, sp., cf. ramosus, Hall.

Vol. 52.] GHOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 531

7. Bala Beds.

Partly surrounded by shales of Arenig age is a great series of
mudstones, grits, sandy flags, sandstones, and conglomerates. These
beds extend from near Mount Pleasant, the residence of Sir Lewis
Morris, for more than a mile in an easterly direction, and probably
farther. They are bounded on the north by the Arenig Beds of the
Roman Road and by the River Towy. On the south they rest on
the Arenig Beds of Glan Pibwr and Cilwaunydd. In the centre of
the series the beds are perpendicular, as is well seen in the flag-
stones and pebble-beds of Bolahaul Quarry, and in the alternating
grits and shales in the quarry opposite Mount Pleasant Nurseries.
Fossils of Bala age have been found at Pensarn, the Star Inn,,.
Allt Cystanog, and Erw-wen. Pensarn is classical ground, for in
the dark-blue brittle mudstones which cccur near the northern
end of the deep lane called the Roman Road, Lady Murchison *
found Stygina [Ogygia| Murchisone, Murch., which was figured
with other fossils from the same locality by Sir R. I. Murchison.
This appears to be a small isolated patch of Bala Beds, as it occurs
between the Arenig Beds of the upper part of the lane and the
Llanvirn Beds to the north. Close to the spot marked ‘ Spring’ on.
the 25-inch Ordnance map we obtained ?Homalonotus, Stygina
Murchisone, Murch., Orthis alata, Sow., and Bellerophon.

Confirmatory Sections.

In alane behind the Star Inn, on the Llandeilo Road, the beds are
more flaggy in character ; here we obtained Lingula tenwigranulata,.
L. levis, Orthis alata, Sow., and Nucula levis. These flags, which
lie on the northern slope of the Mount Pleasant ridge, may be
traced for a short distance up the hill, and are seen again at
Erw-wen, ? mile south-east on the southern slope of the hill.
Here we found Orthis alata, Sow., O. calligramma, Dalm., O. flabel-
lulum, Sow., Lingula, sp., Bellerophon, and Nucula.

At Allt Cystanog mudstones lithologically similar to those of
Pensarn have been turned out of the new lead-mine. Here we
collected Lingula tenuigranulata, Orihis alata, and O. flabellulum.

In a quarry opposite Mount Pleasant Nurseries we found a few
fragments of Holopella.

ITY. Comparison wItH THE Drposits oF OTHER AREAS,
1. Tremadoc Slates.

It is unfortunate that we have not found in these beds a single-
fossil which is characteristic of the Tremadoc Slates in other parts
of Britain. The commonest trilobite that occurs is a new species
of Peltwra, Milne-Edwards; but we have also two other Cambrian
forms: a Parabolinella closely resembling P. rugosa, Brog., which is.

1 ‘Silurian System,’ pt. ii. pp. 358 & 664, & pl. xxv. figs. 3 a, 30.

332 MISS CROSFIELD AND MISS SKEATON THE [ Aug. 1896,

found in the Ceratopyge-Limestone, stage 3a, and Hrinnys, sp.
Associated with these typical Cambrian genera is the Ordovician
genus Ogygia, represented by a large new species, which occurs
sparingly in our lower beds, becomes more common as we pass
higher, and finally is very abundant in beds of Arenig age.

This mixture of Cambrian and Ordovician forms indicates the
position of these beds in the stratigraphical succession, and enables
us to correlate them in a general way with the Tremadoe Slates of
North Wales and with the Shineton Shales of Shropshire.

In the attempt to fix the horizon of these beds yet more definitely
we have compared our fossils with those found in Stages 2 and 3
in Scandinavia’; and we observe that both the subgenera Peltura
and Cyclognathus properly belong to Stage 2 (Olenus-Etage), although
one species of Cyclognathus (to which subgenus our form, strictly
speaking, belongs) is found at the very base of Stage 3 (Asaphus-
Etage).

As Peltura punctata, sp.n., is by far the commonest fossil in our
‘beds, we are inclined to consider that here we have the equivalents
of the lower part of Stage 3a, which Brogger”* has correlated with
the Shineton Shales. On the other hand, the presence of Orthoceras
throughout our beds would suggest that we have the representatives
of 3a or 3a”, for this genus is not recorded by Brogger as
occurring below the upper part of 3a. Our species of Parabo-
linella closely resembles P. rugosa, Brog., which is confined to 3a”.

It thus seems unwise, if not impossible, to define the position of
our beds more closely than by saying that they are of the age of the
Tremadoce Slates, and the equivalents of part or of the whole of
Stage 3a; but as the shales are very rich in fossils, we hope that
additional species will ere long be found to throw further light on
the question.

2. Arenig Beds.

The presence of Phyllograptus, sp., cf. angustifolius, Hall, at Glan
Pibwr, and of Calymene parvifrons, var. Murchison, Salt., in the
Roman Road, and Swansea Road upper stream, both associated
with Ogygia marginata, sp. n., which has come up from the
Tremadoc Beds, indicate the Arenig age of these mudstones; and
that the graptolitic shales of Hafod-wen are of the same period is
shown by the presence together of such forms as Didymograptus
nitidus, Hall, Dictyograptus, sp., and Afglina binodosa. These beds
are the equivalents of the Phyllograptus-shales of Wales and
Scotland, of part of the Skiddaw Slates, of the Lower Graptolite or
Phyllograptus-shales of Norway and Sweden, of the Point Levis
Beds, and of the St. Anne Zone of Canada.

1 Brogger, ‘ Die silurischen Etagen 2 und 3 im Kristianiagebiete,’ 1882.
4 Ibid.

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 533

Lower Arenig.

Phyllograptus angustifolius, Hall, is found in Britain, both in the
Lower and Upper Zones of the Arenig, and has a wide range in
Scandinavia, so that its occurrence at Glan Pibwr is not sufficient
to determine the horizon of the beds. The absence of Calymene
parvifrons, var. Murchisoni, Salt., at Glan Pibwr and Nant Pwntan,
and the very great abundance of Ogygia marginata, which is
also common in the Tremadoc Beds of Cwm Ffrwd, suggest that
possibly these beds are of Lower Arenig age. The evidence which
we obtain from their position in the field supports this opinion. The
Glan Pibwr Beds are only separated from the soft Tremadoc shales of
Cwm Ffrwd by a continuation of low-lying ground, presumably of
the same age; and the Nant Pwntan exposure lies between the
Tremadoc Slates of Cwrt Hir and the graptolite-shales of Hafod-
wen, in the latter of which are fossils from the Tetragraptus-zone.
It is impossible to compare these beds with those of other areas
until more fossils are obtained. ;

Upper Arenig.

In the shales of Hafod-wen occur Didymograptus nitidus, Hall,
D. constrictus, Hall, Dictyograptus, sp., and déglina binodosa, which
determine the Upper Arenig age of these beds. Although we have
not found the characteristic Tetragraptus, yet the similarity of our
fossils to those obtained by the late Mr. T. Roberts, at Talfan etc.,
suggests that at Hafod-wen we have the same beds reappearing.
The shales may be correlated also with the Upper (formerly Middle)
Arenig of St. David’s, and with part of the Tetragraptus-zone of the
Skiddaw Slates described by Mr. J. E. Marr.

We have not been able to determine whether the mudstones of
the Roman Road and Swansea Road stream underlie the Hafod-
wen shales, or whether they are on the same horizon but of a
totally different facies. The association of Calymene parvifrons,
Salt. (atypical Arenig fossil of North Wales, where it is found along
with Ogygia Selwyni), with Ogygia marginata, shows that we cannot
class these beds with the Llanvirn Group. We find also Calymene
parvifrons, var. Murchisoni, Salt.; as this fossil is recorded by
Dr. Hicks from Porth Hayog, Ramsey Island, together with Didy-
mograptus nanus, D. bifidus, D. indentus, and D. patulus, its occur-
rence in the Carmarthen beds points to the probability that they
are near the upper limit of the series.

3. Didymograptus bifidus-shales (Llanvirn).

These beds contain Phacops lanvirnensis, Hicks, Didymograptus
bifidus, Hall, and other fossils common in the Llanvirn (Lower
Llanvirn of Dr. Hicks) of St. David’s, with which beds they are
exactly comparable. The occurrence of Acidaspis Buchii, Barr.,
ecnnects the Carmarthen beds directly with Stage Dd’ of Bohemia,

' Marr, ‘ Notes on the Skiddaw Slates,’ Geol. Mag. 1894, p. 122.

534 MISS CROSFIELD AND MISS SKEAT ON THE [ Aug. 1896,,.

and also with the slates of Angers, in both of which this fossil is
found abundantly in conjunction with Placoparia. These forms.
are characteristic of the well-known Llanvirn fauna, and fix the
position of the shales beyond question.

4. Didymograptus Murchisoni-shales.

These are too well known to require much notice here; they
evidently correspond to Hicks’s Lower Llandeilo or Upper Llanvirn:
beds of Abereiddy Bay, and to part of Messrs. Marr and Roberts’s-
Didymograptus-shales of Haverfordwest. Very few fossils were
found except the characteristic Didymograptus Murchisoni, Beck,
and this was abundant. These beds everywhere succeed the
Didymograptus bifidus-shales which constitute the true Llanvirn
(Lower Llanvirn of Dr. Hicks) horizon. We see the same relations:
of the beds in Scania. Tullberg’s division E, Middle Graptolite
Shales, has at the base a zone O=D. Murchisoni-zone.

ee a dea 3 with Didymograptus Murchisom.

y- Corresponds to part of our Didymo—
graptus bifidus-zone.

5. Dicranograptus-shales.

These beds regularly succeed the Didymograptus Murchisom-
shales: near the base we have a zone containing Deplograptus:
foliaceus, Murch., and D. dentatus, Brongn.; in a higher band
Climacograptus bicorms, Hall, was found. Drcranograptus ramosus,.
Hall, occurs alone, so that the relationships of the sub-zones to-
one another cannot yet be made out. Orthis argentea, which is
characteristic of the upper bands of the Dzcranograpius-shales at
Haverfordwest (Quart. Journ. Geol. Soc. vol. xli. 1885, p. 478), has.
not been found in the Carmarthen district. We have no difficulty
in correlating these beds with the Glenkiln Series described by
Prof. Lapworth, and placed by him at the very top of the Llandeilo-
Series. Not only are the chief fossils identical, but their distribution.
is also strikingly similar, as is shown by the following table :—

GLENKILN Bens. Dicranograptus-sHALES.
Dicranograptus ramosus, Hall. R. R.
Climacograptus bicornis, Hall. C. C.
Diplograptus dentatus, Brongn. R. R.

Fr foliaceus,Murch. C. C.

The same beds occur in Abereiddy Bay, at Haverfordwest, Builth,
Conway, in the Lake District, in County Down, and also in Sweden..

6. Bala Beds.

The age of the fossiliferous part of the Mount Pleasant series is.
determined by the presence of Lingula tenuigranulata, which is
found elsewhere in rocks of Bala age, and is not known to occur on

é

~

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN, 539

a lower horizon. Further evidence for the Bala age of these beds
is the occurrence of Stygina Murchisone, Murch. For many years
Pensarn was the only known locality for this fossil, but it has been
found by Messrs. Nicholson and Marr in the Drygill Shales. A
large assemblage of fossils from the same district has been examined
by Miss Elles and Miss Wood, and they have recently * shown that
these beds are of Bala age.

The grits, sandstones, and conglomerates have only yielded a
solitary fossil, Holopella, so that we reserve our opinion on the age
of this part of the series until we can examine them more fully.
In this connexion it is, however, interesting to note that Sir
R. I. Murchison considered the ‘ schists,’ grits, and sandstones as of
one and the same age; but he compared them with the slates of
Angers, and placed them at the very base of the Llandeilo.

Y. DEscRIPTION OF SOME NEW SPECIES oF TRILOBITES.
Genus Peltura, Milne-Edwards.

Peltura punctata, sp.nov. (Pl. XXVI. figs. 1-10.)

General form.—Long oval, slightly narrowing towards the posterior
end. Very gently convex. Trilobation distinct.

Head.—Rather more than a semicircle, wider than long; length
about 2 that of the whole body, surrounded by a narrow raised
border, which widens slightly in front of the glabella, where it is
ornamented by a row of about twenty puncta placed in a groove.
Glabella gently convex, parallel-sided, longer than broad, with two
pairs of distinct lateral furrows curving slightly backward, a third
anterior pair being sometimes very faintly visible. The second and
third pairs of furrows occupy rather more than 4 of the width of the
glabella. Axal furrows well marked. The neck-furrow cuts off a
wide segment, and extends right across the posterior end of the
glabella. The neck-segment is crossed on each side by a sloping
furrow, which cuts off a triangular piece as-in Peltura scarabwoides.
In the centre of the segment is a small tubercle. The fixed cheeks
are large, triangular, and gently convex; the neck-furrow on the
cheeks is very near the posterior margin, this furrow is continued
round the genal angle and a little way up the side. Free cheeks
narrow, generally absent. Genal angles rounded. Eyes small,
placed very far forward, just below the punctate border. Palpebral
lobe prominent. Ocular ridge distinct on some specimens, but not
always well marked off.

Thorax with twelve segments ; nearly half as long again as the
head. Axis wider than the greatest width of the pleura, gently
tapering towards the posterior end. In the centre of some of the
segments a small tubercle is visible. Pleura nearly straight, sharply
elevated as far as the fulcrum, which is placed } or less of the

1 Miss G. L, Elles and Miss E, M. R. Wood ‘ On the Drygill Shales,’ Geol,.
Mag. 1895, p. 246.

O.4.G. 8: Nov 207; 20

536 MISS CROSFIELD AND MISS SKEAT ON THE [Aug. 1896,

distance out, and then gently decurved. Obliquely grooved through-
out their length; ends rounded anteriorly, but with exceedingly
short sharp points curving backward, closely resembling those of
Cyclognathus micropygus.

Pygidium very small, much broader than long. Axis wide,
marked with three rings, not continuous across. Terminal portion
small. Side lobes with two or three faint furrows. Margin
entire? A single rolled-up specimen was found at Nant-y-
- Glasdwr.

We recognize this species as belonging to the genus Péltura,
Milne-Edw., from the forward position of the eyes, their small
size, the rounded genal angles, and the pointed pleura; but we
refrain from placing it in any of the recognized subgenera. We
consider it closely related to the species of the subgenus Péltura
(sensu stricto), Ang., and yet more so to those of Cyclognathus,
Linrs. This latter subgenus is, however, too ill defined to be of
practical use as it stands. The chief distinctions between Cyclo-
gnathus, Linrs., and Peltura (sensu stricto), Ang., are that in
Cyclognathus the glabella-furrows are indistinct or absent, and the
pygidium is generally small, with an entire margin; in Péeltura, on
the other hand, the glabella-furrows are distinct and the margin
toothed. Cycloynathus transiens, Brég., however, bridges over the
gap between the two subgenera by having teeth on the margin of
the tail; further, in Cyclognathus costatus, var. minor, Brog., the
glabella-furrows are as distinct as in Peltura scarabeordes.

Brogger also shows that Linnarsson’s distinction, based on the
small size of the tail in Cyclognathus, does not hold. For this
reason we refer this new form simply to the genus Peltura, Milne-
Edw.

It differs from Peltura scarabeoides, Wahlenb., in the shape of
_ the glabella, which is parallel-sided, not parabolic, and in the shape
of the fixed cheeks. ‘These in P. scarabeoides taper more towards
the anterior end, and do not extend so far forward. The new form
has a row of puncta in the groove between the anterior border and
the glabella, the pleura do not taper towards the ends, and the
points of these are much shorter than in P. scarabeoides. he
pygidium is also here very much smaller, and the margin appears to
be entire, not toothed. The free cheek is very much narrower than
in any species of Peltura. The form of the pleura and fixed
cheeks, the punctate border and entire. margin of the tail algo
distinguish this form from Peltura bidentata, Brog., and the latter
feature from P. planicauda, Brog. In the shape of the pleura it
approaches very nearly to Cyclognathus micropygus, Linrs.; the
pygidium seems to be intermediate between those of Cyclognathus
micropygus, Linrs., and C. costatus, Brog.; but the head differs
widely from either of these.

Localities and Horizon: Nant-y-Glasdwr, Cwm Ffrwd, Cwrt
Hir, Carmarthen. Tremadoc Slates.

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 537

Measurements of Peltura punctata, sp. nov.

(These measurements are of a medium-sized but almost perfect
specimen. )

Inch.

aM dens eee aae deiokine cosiecoancsedsovunnces een "94
MUONS Cette ciate cf aicelas de'e cairns (obsabe mete team dae “o4
MRR NRPS pn tou cassis no Saale Sle cinn's amie cinja Seieinaiv'einnlb 52
iP SULDaReS Oe eee Oe ‘08
“AUT USMC ALINE 5 WP ape oo ee eres Ne a ‘40
Greatest width of plabella: 2... cs. ccncssceseossducecees ‘22
Wadthrof alabellay at base? .2..0l..cccckeeerescecvsnonse ‘20
Gecatents With On OOUy pei ztmcsink edcsseageisslaeccaeceas “44

“ a PEt fed sic a cae aslca senate sain 14

¢ ey UR gee raat Pecan ase hamaacaesen ‘20
Distance of fulcrum from axi8 .............0fecceesees ‘04

Genus Olenus, Dal. Subgenus Paradolinella, Brég.

Parabolinella, sp. nov. (Pl. XXVI. figs. 11 & 12.)

This trilobite presents sufficient differences from the P. rugosa
described by Brégger to admit of its being considered a new species
or variety. As we have, however, only one specimen, and that is
somewhat imperfect, we prefer to withhold a complete determination
until better specimens are found. The present example consists of
the glabella and fixed cheeks only; it is a good deal larger than
Brégger’s figured specimen of P. rugosa, being *46 inch long and
‘5 inch wide. As in P. rugosa, the glabella narrows slightly
forwards, but it 1s somewhat wider in proportion to the length
than is the case in that form. A very small portion of the anterior
margin is seen on the right side. Here, too, there are three prin-
cipal pairs of glabella-furrows, of which each anterior furrow is
shallower in the middle ; the two posterior pairs being bent sharply
backward, aud also branched. The branching is, however, not
quite identical with that which occurs in the furrows of P. rugosa,
as the second branch of the posterior furrow deepens more towards
the middle, where it joins the first branch, and less towards the

eexterior side of the glabella. The most striking difference between
the two forms lies in the structure of the additional pair of furrows,
which occurs between the posterior pair, mentioned above, and the
neck-furrow. ‘This pair is very distinctly seen, and each furrnw
is double instead of being single as in P. rugosa; thus a natiow
raised piece is included between the two forks. The eyes are
large and occur in. the same position as those of P. rugosa. The
fixed cheeks are very narrow, but widen out posteriorly to more
than § the width of the glabella and have a well-marked neck-
furrow. The neck-segment resembles that of P. rugosa, but has no
central tubercle.

Locality and Horizon: Nant-y-Glasdwr, Carmarthen. Tremadoc
Slates.

538 MISS CROSFIELD AND MISS SKEAT ON THE [Aug. 1896,

Genus Ogygia, Brongn.
Ogygia marginata, sp. nov. (Pl. XXVI. figs. 13-26.)

This is a fine large species, attaining a !ength of at least 5 inches,
although most of the specimens obtained were not more than
24 inches long. The description is of the ‘forme longue,’ except
when otherwise specified.

General form.—A true oval, flat, or gently convex; trilobation
distinct.

Head.—A broad segment of a circle, surrounded by a striated
concave border, which is narrower in front, and at the genal angles
is produced into long sharp spines. The length of the head as
compared with the breadth is about 2:5. The glabella is long,
narrow, almost parallel-sided, especially in young specimens, marked
off from the fixed cheeks by a deep axal furrow all round. In
older forms it is distinctly clavate in front and very slightly con-
tracted in the middle. The surface is flat except for the frontal lobe,
which is gently convex. There are traces of two pairs of glabella-
furrows, (i) behind the convex frontal lobe, (11) opposite the base of
the eyes. These are very indistinct, and absent in much-com-
pressed specimens. The neck-furrow is incomplete in the middle,
and the two side parts of it run backward towards the narrow
marginal furrow: thus the occipital ring,—which has a small
tubercle in the centre,—is wider than the posterior margin of the
fixed cheeks. The corresponding furrows on the fixed cheeks are
broad, deep, and quite straight. The fixed cheeks are continuous
round the glabella anteriorly ; they widen out considerably at each
side of the frontal lobe, and also in the middle of the glabella in
front, where they follow the course of the facial suture and form
a slight point. This portion of the fixed cheeks is convex and is
marked with striations similar to those on the anterior margin,
which it partially invades. The free cheeks are broad, gently convex,
with a fairlv wide concave margin, and are produced at the genal
angles into long sharp spines. On their inner side is a groove
running parailel to the surface of the eye. The eye is situated
about halfway up the glabella; it is of medium size, lunate, with
the lentiferous surface rather narrow. The facial suture cuts the
posterior margin about = of the way out, and is intramarginal in
front. It seems to run very near the margin, and forms a small
angle in the middle. The hypostome in our specimens is incomplete
posteriorly, but is clearly triangular in shape, with a broadly arched
base; at the posterior end, where it is narrow, it is traversed by
two pairs of deep converging furrows. The duplicature of the
margin, as also the hypostome itself, are covered with fine striations.
In the middle of the former the ‘suture médiane de jonction’
described by Barrande is distinguishable.

Thorax short, rather less than 3 of the total length, with eight
narrow well-defined segments. Axis narrow, about 7 the whole
width (in the ‘forme large, of which we probably have two
specimens, the axis is nearly 3 the whole width) convex, nearly

a

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 539

parallel-sided. Pleura nearly straight, but slightly bent down at
the fulcrum, which is situated about half the distance out; grooved
and facetted, also marked beyond the fulerum by numerous fine
strie. The ends of the pleura are obliquely truncated, but produced
posteriorly into short sharp points.

The pygidium is more than 3 the total length and about 2 broader
than long. It is surrounded by a deeply concave striated margin,
which is strongly marked off on the inner side by a high convex rim.
Axis narrow, tapering gently and ending in a tumid point on the
inner rim of the concave margin. It is annulated by six to eight
furrows, and the side lobes are marked by a corresponding number
of furrows, which reach the inner rim of the margin, where they
abruptly terminate.

This species seems to stand halfway between Ogygia Selwynii,
Salt., and Ogygia corndensis, Murch. It differs from O. Selwynii

‘in the following respects :—

(1) The head and tail of O. Selwynii are equal in length, but in
this species the tail is longer than the head.

(i) The genal spines of O. Selwynit are considerably shorter and
stouter.

(111) The hypostome of O. Selwynii is broader in proportion to its
ength.

(iv) The margin of the pygidium in O. Selwynii is broader and
less concave, and indistinctly marked off from the rest of the tail.
The side furrows are also very short. In the new species the
furrows are long and extend quite up to the margin, which is
marked off by a high convex rim.

It differs from O. corndensis in the following respects :—

(i) The axis in O. corndensis is throughout a good deal broader,
and that of the tail narrows suddenly, so that its sides are curved.

(ii) The margin of the pygidium in O. corndensis is indistinctly
marked off and is waved by the lateral furrows, which is never the
case in this new species.

(iii) The genal spines are slightly longer in O. corndensis.

(iv) The glabella in O. corndensis is shorter in proportion to its
width.

(v) The tips of the pleura in O. corndensis are abruptly truncated,
and sometimes bluntly rounded, whereas here we have curving sabre-
tips, like those of 0. Buchii, but shorter.

The feature which marks this species off from other Ogygie is
that the margin is raised in a fold towards the inner edge.

Localities and Horizons: Nant-y-Glasdwr, Cwm Ffrwd, Cwrt Hir,
Glan Pibwr, Nant Pwntan, etc., Carmarthen. Tremadoc Slates.—
Arenig.

VI. Conciusion.

In offering these suggestions with regard to the succession in the
neighbourhood of Carmarthen, we feel sure that further evidence
will cause many alterations in the boundary-lines which we have
drawn between the various series, and we have little doubt that the

540 MISS CRCSFIELD AND MISS SKEAT ON THE [ Aug. 1896,

area in question is much more faulted than appears in our sketch-
map.

Among the problems which demand solution, that of the relations
of the Bala Series of Llangunor and Mount Pleasant to the older
rocks is perhaps the most important.

A comparison of the position of the grits and conglomerates in the
Tremadoe and Llanvirn Beds of Carmarthen with those of the
Tremadoc, Arenig, and Llanvirn Series of other British areas would
prove valuable, but to draw this comparison satisfactorily we must
wait until more exact paleontological correlations can be made. —

Our warmest thanks are due to Mr. Marr—by whose advice we
undertook this work—for many valuable suggestions with regard to
it, and for his help in the identification of some of the specimens.

We also gratefully acknowledge our indebtedness to Prof.
Lapworth, who has examined and named some of our graptolites.

EXPLANATION OF PLATES XXV. & XXVI.

Pate XXV.

Geological sketch-map of the neighbourhood of Carmarthen.
Scale: 1 inch=1 mile.

Puate XXVI.

Fig. 1. Peltwra punctata, sp. nov. Shows the punctate border and a tubercle
onthe second body-segment. x13. From the Tremadoc Slates, Nant-
y-Glasdwr, Carmarthen.

2. P. punctata, sp.nov. X14. Same locality.

3. P. punctata, sp. nov. X14, Same locality.

4. P. punctatu, sp. nov. Shows the delicate tips of the pleura. X13.
Same locality.

5. P. punctata, sp. nov. A perfect head, somewhat crushed. x2. Same
locality.

6. P. punctata, sp.nov. Cast of free cheek. 2. Same locality.

7. P. punctata, sp.nov. <A large head; the free cheeks are missing.

Natural size. Same locality.

8. P. punctata, sp. nov. Shows the punctate border, the glabella-furrows,
the tubercles on the first two body-segments, and the tips of the
pleura all distinctly. x13. Same locality.

9. P. punctata, sp.nov. A rolled-up specimen. X2. Same locality.

10. P. punctata, sp. nov. Two pleura enlarged. 5. Same locality.

11. Parabolinella, sp. nov. Head imperfect, the only specimen found.
Natural size. Nant-y-Glasdwr, Carmarthen.

12. Parabolinella, sp. nov. Counterpart of portion of fig. 11.

13. Ogygia marginata, sp.nov. Body and tail nearly perfect. Shows the
sabre-like tips of the pleura. Natural size. Nant Pwntan,
Carmarthen.

14. O. marginata, sp. nov. Possibly the ‘forme large’ 9. Natural size.
Cwm Ffrwd. Carmarthen.

15. O. marginata, sp. nov. Natural size. Nant Pwntan, Carmarthen.

16. O. marginata, sp. nov. Imperfect glabella. Shows traces of furrows,
and a tubercle on the occipital ring. Natural size. Same locality.

17. O. marginata, sp. nov. A young specimen, much distorted. Natural
size. Same locality.

18. O. marginata, sp. nov. Shows free cheek and genal spine. Natural
size. Same locality.

Quart . Journ. Geol. Soc -Vol.LII. PI XXVI-.

Mintern Bros imp.

T.H.Michael lth.

CARMARTHEN TRILOBITES.

Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 541

Fig.19. O. marginata, sp. nov. A crushed and distorted specimen. Shows that
the course of the facial suture is probably intramarginal. Natural
size. Swansea Road stream, Carmarthen.

20. O. marginata, sp. nov. Hypostome; imperfect. Natural size. Glan
Pibwr, Carmarthen.

21. O. marginata, sp. nov. Counterpart of fig. 20.

22. O.marginata,sp. nov. Glabella of a very small specimen. Shows the
tubercle on the occipital ring. Natural size. Glan Pibwr, Carmar-

then.

23. O. marginata, sp.nov. Shows the hypostome and free cheek. Natural
size. Nant Pwntan, Carmarthen.

24. O. marginata, sp. nov. Ditto. Same locality.

25. O. marginata, sp. nov. Shows the eye and part of the facial suture.
Natural size. Glan Pibwr, Carmarthen.

26. O. marginata, sp.noy. The glabella of a large specimen. Natural size.
Same locality.

DIscussion.

The PrestpEenr congratulated the Authors on the important dis-
coveries which they had made. The finding of Tremadoc rocks in
the neighbourhood of Carmarthen was a fact of great importance,
and might lead to the discovery of still older rocks in that area.
The succession closely resembled that found in Pembrokeshire; but
it was now carried farther east than had previously been done,
though the work of the late T. Roberts and Mr. Marr had led one
to anticipate that rocks at least as old as those of Arenig age would
be found in this area.

Dr. Woopwarp congratulated the Authors on the admirable
series of fossils which they had collected, and especially on the
very beautiful species of trilobites which they had added to the
British fauna, in particular the specimens of Peltwra punctata and
Ogygia margmata. The latter form recalled to him the Asaphus
(Ptychopyge) corndensis, Murch., referred to by Wyatt-Edgell (Geol.
Mag. 1367, pp. 14-18), but this species is from the Llandeilo Beds,
not from the Tremadoc.

Mr. Marr stated that the work done by the late T. Roberts and
himself (and no doubt also the work of the Authors of the present
paper) was largely facilitated by the published maps of the Geological
Survey. He believed that the Tremadoc age of the beds claimed as
of that date was thoroughly established. ‘The Dicranograptus-shales
had hitherto yielded Hartfell graptolites only. He believed that
Glenkiln forms had been discovered by Mr. Roberts and himself in
the Haverfordwest area, but they were very badly preserved and
not really identifiable. They should be looked for elsewhere.

Mr. Hopxinson and Dr. Hinpz also spoke,

542 PROF. PAVLOW ON THE CLASSIFICATION OF THE [Aug. 1896,

32. On the Crassrrication of the Srrata between the KIMERIDGIAN
and Aptian. By Dr. Atexts P. Paviow, For. Corr. G.S.,
Professor of Geology in the University of Moscow. (Read
March 25th, 1896.)

[Prate XXVII.]
ConTENTS.
Page
La Schemestoh @lacsiiCabvOn ssi dsciic. cetzc- vine acetone ssieoatoteeeeee 542
II. On the English and German Species of Aucdls,. ae 549
TLE (Generali Constderations) «oc... acceso. > te ces sccaceeloee sees sReneeeee 5ol

I. ScuEmEs oF CLASSIFICATION,

In the paper on the Speeton fauna, forming a part of the work
which I wrote in conjunction with Mr. G. W. Lamplugh, I attempted
to correlate the Upper Jurassic and the Lower Cretaceous horizons
of Speeton with their equivalents in Russia and in different parts
of Europe, and to give a general scheme of classification of these
beds. This scheme may be briefly stated as follows.

The Kimeridgian zone of Hoplites pseudomutabilis and Aspido-
ceras acanthicum is common to different countries of Hurope. Above
this zone in the Meridional province repose the marine beds of the
Tithonic stage, terminating the Jurassic. These beds comprise two
substages—the Lower Tithonic, which contains two fossil-zones ;
and the Upper Tithonic, also containing two zones. To this Tithonic
stage corresponds in Southern England the Portland stage sensu
lato, including the Lower marine series (Portland, sensu stricto, or
Bononian Series), and the Upper freshwater Portland or Purbeck.
In Northern France and partly in Southern England three fossil-
zones can be distinguished in the marine Portland, namely, the zone
of Ammonites portlandicus and Bleicheri, the zone of Virgati, and the
zone of A. giganteus. In Yorkshire the equivalents of this series
are condensed, and moreover the freshwater Purbeck is replaced by
marine beds with Belemnites lateralis, deposited in a separate boreal
marine basin. To designate these uppermost horizons of the
Jurassic in its marine development, I proposed the name ‘ Aquilonian’
stage or substage, including in this term the zone or zones of Ammo-
mites fragilis and nodiger and the zone of Polyptychites (Keyserlingt,
gravesiformis, ete.). The last-mentioned zone, being the uppermost
of the Tithonic stage, was described as being characterised by the
_ presence in its fauna of many Cretaceous elements.

In Russia the equivalents of the marine Portland of France and
the Aquilonian stage are well represented and rich in cephalopoda—
those most trustworthy guides in the deductions of comparative
stratigraphy. To the zone of Polyptychites Keyserlingi, gravesi-
formas, ete., with its many Cretaceous fossils, the name of ‘ Petchorian’
was applied, and in the general scheme this was placed at the top

Vol. 52.] STRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 543

of the Aquilonian stage. Notwithstanding the presence of numerous
Cretaceous species in these beds in Russia and in England, I found
it on the whole more convenient to class them as Jurassic, noting,
however, that they formed the uppermost Jurassic strata, lying at
the extreme limit of the two systems. In adopting this view I was
guided by the following considerations. Both in Russia and in
England the fauna of this horizon is more closely related to the
fauna of the underlying than to that of the overlying beds; and
also the undoubtedly Neocomian fossils, such as Ammunites Astieri,
Hoplites regalis, Belemnites pistillirostris, etc., are found only above
this horizon, their appearance bringing all at once a new element into
the fauna. Moreover, the Cretaceous species recognized among the
representatives of the genus Polyptychites in the Petchorian strata
had mainly been found in the Hils Beds of Germany, whose strati-
graphy has been incompletely studied.

My scheme of the Russian subdivisions indicated that there was
a well-marked stratigraphical and faunistic break between the zone
of Polyptychites Keyserlingi and the Simbirskian Neocomian beds,
with Simbirskites versicolor, Decheni, and discofaicatus, which latter
represented apparently the boreal development of the Upper Neoco-
mian with possibly also the upper part of the Middle Neocomian ;
and that the beds with Hoplites regalis and Asteria Asticri were
absent in Russia. But there were still other horizons, not strictly
defined paleontologically and stratigraphically, which by their
position, as it was then understood, might be regarded as lying
near the limit between the Jurassic and Cretaceous systems. The
fauna of one of these horizons displayed an affinity to the Upper
Tithonie fauna, and the fauna of another was closely related to
that of the zone of Polyptychites Keyserlingi. I refer here to the
zone of Hoplites riasanensis, and to that of Olcostephanus hoplitoides
of the government of Riasan. I had not then the necessary
material for defining strictly the position of these horizons in the
stratigraphical series, but I presumed that one of them, namely the
zone of Olcostephanus hoplitoides, might represent a Lower Neocomian
horizon of a still unknown boreal type, and that the other—that is,
the zone of Hoplites riasanensis—might represent a mixed type of
the Lower Neocomian.

Shortly after the publication of these results it was demonstrated,
by my further researches and the paleontological studies of M. W.
Stchirowsky * in the Geological Museum of Moscow, that in the
northern part of the government of Simbirsk (districts of Alatyr
and of Kurmysh) there exists a horizon the fossils of which show
affinities both with the zone of Craspedites subditus and nodiger,
and with that of Polyptychites Keyserlingi. Having seen the great
interest which attached to the study of these horizons, I entered
upon new researches, in the zones both of Olcostephanus hoplitoides
and of Hoplites riasanensis, in the region of their greatest develop-

1 *Ueber Ammoniten der Genera Oxynoticeras und Hoplites aus dem nord-

simbirsk’schen Neocom,’ Bull. Soc. Imp. Nat. de Moscou, n. s. vol. vii. (1893)
p: 369.

544 PROF. PAVLOW ON THE CLASSIFICATION oF THE [ Aug. 1896,

ment, in the government of Riasan, and these were at the same
time studied by M. Bogoslowsky.*

As the result of these researches, I am now enabled to give a
more complete and correct scheme of the Upper Jurassic and Lower
Cretaceous succession in Russia, or, in other words, in the Boreal
province. The study of the close of the Jurassic and the beginning
of the Cretaceous times in this region helps largely in the deter-
mination of the position of the different horizons of the same series
in other countries, especially in England and Germany; and the
further working out of the common classification of these beds may
be thus facilitated.

The grounds on which this new scheme is based are as follows.
My researches near Kashpur, in the district of Syzran, have
shown that below the horizon of Polyptychites polyptychus, Key-
serlingt, syzranicus, and between this horizon and the zone of Cras-
pedites kashpuricus and Oxynoticeras subclypeiforme, there exists a
bed of sandy marl (about 1 metre in thickness) very rich in Auceélla,
especially Aucella volgensis. This bed, which has both above and
below it a smallseam of glauconitic sand, includes (along with some
fossils proper to the zone of Polyptychites Keyserlingi) a series of
especially characteristic forms, which are known also from the
before-mentioned bed in the districts of Alatyr and Kurmysh,
including Ammonites stenomphalus and Marcousanus. Owing to
the close relations of the bed with the zone of Polyptychites Keyser-
lingt, I find it convenient to unite it therewith, and to apply to
both the name of the Petchorian Series; and this 1s the more
convenient, since, judging from a collection of fossils not yet de-
scribed, brought to me by M. A. Ivanow from the region of Petchora,
and also from some literary data, both faunas exist there in
closely related beds. At Kashpur both the lower and the upper
zones of the Petchorian Series can be distinguished, and both are
rich in Belemnites lateralis, subquadratus, and russiensis. In the
districts of Kurmysh and Alatyr only the lower zone has been dis-
covered, and M. Stchirowsky, who has described a part of its fauna,
has recorded therein such forms as Oxynoticeras Gevrilanum and
Marcousanum, which are generally regarded as Lower Neocomian.
Such forms are, however, very rare among the numerous and entirely
new species of ammonites, more or less nearly related to Ammonites
stenomphalus. (1 am now engaged in describing this remarkable
fauna. )

The presence, though very rare, of Lower Neocomian types in’
this zone is an argument in favour of considering the whole

1 A. Pavlow, ‘On the Mesozoic Beds of the Government of Riasan,’ Report
of the Geological Excursion undertaken in the summer of 1893, Scient. Rec. _
Imp. Univ. Moscow, sect. Nat. Hist. pt. ii. (im Russian); N. Bogoslowsky,
‘Volgian, Upper Tithonic, and Neocomian Beds in the Government of
Riasan,’ Preliminary Report, Materialen zur Geologie Russlands, vol. xvii.
1895 (in Russian).

2 The correlation of these beds in the different countries of Europe was
the subject of a communication made by me to the International Geological
Congress at Ziirich in 1894.

-

Vol. 52.] sTRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 545

Petchorian Series, that is, the zones of Ammonites stenomphalus and
of Ammonites Keyserling?, as being the Lower Neocomian of Boreal
type, notwithstanding the affinity of their fauna with that of the
underlying zones of the Aquilonian, of which the Jurassic age is
thus more strongly defined.

But if it should prove locally inconvenient to fix the lower limit
of the Cretaceous at a lower level than the base of the zone of
Hoplites neocomiensis and regalis, then these Petchorian beds and
their equivalents may be considered as an intermediate series
between the two systems, to be placed either with the Jurassic or
with the Cretaceous, after the stratigraphical and faunistic rela-
tions of the beds with Ammonites Marcousanus and Gevrilianus of
Central Europe have been thoroughly studied, and their equivalents
and relationship to the underlying and overlying beds more com-
pletely understood. This, however, seems to me a less convenient
course than that which I have proposed above, since it still leaves the
limits of the systems indefinite, though no doubt it might in some
countries suit better the local conditions as displayed in the litho-
logical or paleontological sequence.

In the Syzran region the next underlying horizons to the beds
above described are a thin band (20 centimetres) of bituminous
shale and a thin band of greenish sand, both very poor in fossils ; and
still lower come asandstone and conglomerate with Aucella volgensis,
trigonoides, Fischeri, Ammonites kashpuricus, subclypeiformis, and
many other ammonites allied to nodiger and kashpuricus.

In the government of Riasan the succession of the Upper Jurassic
and Neocomian beds is as follows :—The beds with Cardzoceras alter-
nans are overlain by a thin band of glauconitic sand and phosphatic
nodules containing several species of Virgutites. This bed thins out
here and there, and is reduced to a narrow band of phosphatic
nodules only (as at Speeton). The next bed is a glauconitic sand,
with Ammonites fragilis and catenulatus and phosphatic sandstone
with A. kashpuricus, subclypeiformis, Belemnites mosquensis, many
species of Aucella (mosquensis, Fischeri), ete. This bed is very
thin, and passes insensibly upwards into the zone of Hoplites riasan-
ensis, Without changing its lithoJogical character.’ This passage
is indeed indicated enly by the substitution of the forms of the group
of Hoplites riasanensis for Ammonites kashpuricus and subclypei-
formis, the rest of the fauna remaining almost unchanged. The
same Belemnites and Aucelle form a characteristic feature in the
fauna and impress upon it a boreal character, which contrasts
markedly with the meridional type of certain of the Hoplites more
or less resembling Upper Tithonic forms. This occurrence of Upper
Titbonic forms at the top of the zone of Craspedites kashpuricus
and Oxynoticeras subclypeiforme, constituting the uppermost zone

1 These relations are to be seen at the village of Kusminskoie. There are
other places (Old Riasan) where the nodiger-zone, and even the catenulatus-
zone, is absent, and the bed with the Huplites riasanensis-group is much thicker
than at Kusminskoie, Possibly such cases indicate that the riasanensis-fauna
appeared there somewhat earlier.

546 PROF. PAVLOW ON THE CLASSIFICATION oF THE [ Aug. 1896,

of the so-called Volgian stages, shows clearly the Jurassic age of
both of these stages, and cuts the ground from under the feet of the
defenders of the Cretaceous age of one or both of these stages.

This bed, with Hoplites of the riasanensis-group, thus capping
the Upper Jurassic Series, passes upwards in its turn into a
glauconitic sandstone with the fauna of the lower zone of the
Petchorian, that is to say, of the boreal Lower Neocomian series.
The Hoplites of the rrasanensis-group, though rare, continue to be
met with in this bed, which contains also a great number of Aucelle
(especially .A. volgensis) and Belemnites of the lateralis- and sub-
quadratus-groups. This bed is, in turn, capped by sands containing
rough sandy phosphorites with Olcostephanus hoplitoides, representing
the upper zone of the Petchorian Series, that is, the zone of Poly-
ptychites polyptychus and Keyserlingi, and we find there many forms
common to the corresponding horizon of Syzran and of the Petchora
region. ‘The fauna of this second horizon of the Petchorian is very
rich and varied. Its most characteristic fossils are ammonites of
the group Polyptychites, belemnites of the lateralis and subquad-
ratus groups, and some species of T’rigonia. -Aucelle are very rare
in this zone in the government of Riasan. Recently I have found
in it afragment of Hoplites neocomiensis, which facilitates the corre-
lation of the zone, and of the whole Petchorian, with the corre-
sponding zones of the Lower Neocomian of Western Europe.

Thus we have in Russia a well-developed ‘ Aquilonian’ stage,
corresponding to the Purbeck, and an equally well-developed ‘ Lower
Neocomian,’ having many species in common with the West European
Lower Neocomian but bearing a special stamp, expressed in the
presence of fossils of boreal type, especially of many species of
Aucelle (partly undescribed) and of belemnites of the subquadratus
and lateralis-groups. This boreal Lower Neocomian (Petchorian
Series) bears a close faunistic relation to the underlying Jurassic
rocks of the Aquilonian stage, and is in Russia marked off by a
well-defined break from the Upper Neocomian (beds of Simbirsk), the
intermediate beds of Speeton with Hoplites regahs being here absent.

The Russian Lower Neocomian is, moreover, subdivided into
two zones: (1) The lower zone of Olcostephanus stenomphalus,
corresponding to the zone of Ammonites Marcousanus, and indeed
containing rare representatives of this species; and (2) The upper
zone of Polyptychites polyptychus and Keyserlingi, corresponding
to the zone of Hoplites neocomiensis and containing very rare repre-
sentatives of this species.

The Aquilonian stage, which is the marine equivalent of the
Purbeck, is also subdivided into the following zones (from below) :
(1) zone of Ammonites fragilis, subditus, and catenulatus; (2) zone
of A. nodiger and subclypeiformis ; (3) zone of Hoplites riasanensis.
All these zones are so related to each other by the presence of the
same Belemnites and Aucelle as to form a natural group, corre-
sponding to the Purbeck and to the Upper Tithonic, and containing
in the uppermost zone forms with Neocomian affinities.

.
Vol. 52.] STRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 547

Turning now to the consideration of the subdivisions of the same
series in other countries, I cannot add much to the correlations
already published in my paper on the Speeton fauna.

As regards England, we see now that the Neocomian is here
more completely developed than in Russia, the zone of Hoplites
regalis being well represented at Speeton. If, however, we begin
the Neocomian with the bed containing Ammonites plicomphalus
and ammonites of the group of Polyptychites, the beds D,_; of
Speeton must be carried over to the Neocomian. I regard it as
possible that at some future time two distinct zones will be distin-
guished there, corresponding to the zones of Ammonites stenom-
phalus and of Polyptychites Keyserlingi. In Lincolnshire the Claxby
Ironstone should probably be considered as Cretaceous, while the
greater part of the Spilsby Sandstone appears to belong to the
Upper Jurassic (Aquilonian).

In Germany all the zones of the Neocomian seem to exist (a good
specimen of Simbirskites progrediens, from Salzgitter, is preserved
in the Gottingen Museum), but the stratigraphy of the beds presents
many difficulties and requires further researches. I am therefore
able to give only a provisional classification of the faunistic sequence
of this region. (See Table facing p. 548.)

Tn the southern regions of Europe we have to consider the question
of the Upper Tithonic and Berrias beds. In Russia the Hoplites
closely related to Upper Tithonic types make their appearance in the
uppermost zone of the Aquilonian, and in one region (government
of Riasan) some rare forms continue into the lower zone of the
Lower Neocomian. When this fauna shall have been sufficiently
studied, it promises to yield very interesting results, since very
nearly allied, and possibly identical, ammonites have been found
in South America,’ and perhaps in Tibet. As for the Berrias of
Southern Europe, I am inclined to consider that this horizon, from
its close faunistic connexion with the Upper Jurassic, should be
ranged with that system. But since some Lower Neocomian forms
are found in it, and since in many areas it has been customary to
carry even the whole Berrias into the Cretaceous, it may be found
convenient, for the sake of working out a common classification,
to divide this transitional series between the two systems, placing
the Ardescian (with the Lower Berrias) with the Jurassic, and the
uppermost Berrias with the Cretaceous. This question must, how-
ever, be further studied in the region where the typical Ardescian
and Berrias are fully developed, and especially in the northern part
of that region.

For the solution of this question it is necessary that one should
find the fauna with Hoplites Malbosi, Euthymi, ete., and also the
fauna with Oxynoticeras Gevrilianum and Marcousanum, in one and
the same section, so that the mutual relations of these two faunas
could be exactly studied ; and this appears to be a very delicate
and difficult task.

1 Hoplites mendozanus, Zeitschr. d, Deutsch. geol. Gesellsch. vol. xliii. (1891)
p. 399 & pl. xxv. fig. 2.

548 PROF. PAVLOW ON THE CLASSIFICATION OF THE [Aug. 1896,

The scheme illustrated in the accompanying Table has been drawn
up to lilustrate the correlations of the beds above discussed, in the
light of our present knowledge. Naturally, I have found it possible
to give more details rezarding the Russian than the foreign beds.

In Russian literature the name ‘ Volgian’ stage or stages is still
applied to designate certain beds of the series in question, namely
the beds ranging from the virgatus-zone of Portland to the nodiger-
zone of the Aquilonian. Many other divisions of our series have
been supposed to be contemporaneous with parts of these zones ;
for instance, the bed with Hopiites riasanensis of the government
of Riasan has been correlated with the zone of Virgatites virgatus,
and the bed with Olcostephanus hoplitoides of the same region has _
been held to be contemporaneous with the nodiger-zone. The ex-
planation of these views will be found in tracing the growth of our
knowledge of these deposits. Prof. Rouillier established in 1845
the divisions of virgatus and catenulatus-beds, otherwise called the
Middle and Upper Moscovian stages,’ and strictly-defined geogra-
phical types were indicated for each of them. The further progress
of research in this branch of Russian geology was directed to
the investigation of the geographical extent of these stages and
to the study of their fauna. Prof. Neumayr, in his remarkable
work, ‘Die Ornatenthone von Tchulkowo und die Stellung des
Russischen Jura’ (1876), being without sufficient evidence to fix
the position of these stages in the stratigraphical series, expressed
the opinion that they might represent a peculiar group of beds
formed in the Russian basin after its separation from the West
European sea. ‘These two stages were soon afterwards united under
the common name of the ‘ Volgian stage’ (from the vast Volga basin),
and this new title supplanted the previous names. From this time
there was a growing tendency to include in the ‘ Volgian stage’ all
the Upper Jurassic and Lower Cretaceous beds whose geological
age was not strictly defined, and hence it followed that various
horizons were from time to time considered to be contemporaneous
- sometimes with the virgatus-beds and sometimes with the catenulatus-
nodiger-beds. Under these conditions it was inevitable that there
should be introduced into the Volgian stage very different horizons of
the Jurassic and of the Cretaceous; and after a short time this stage
was divided anew into two separate stages—the ‘ Lower Volgian,’
corresponding to the virgatus-beds of Rouillier, and the ‘ Upper
Volgian,’ corresponding to the catenulatus-nodiger-beds of the same
author. The fluctuation of opinions which has taken place respecting
the age and extent of these stages is very natural, since the term
‘Volgian’ was sometimes applied to all the Upper Jurassic rocks
down to the base of the Kimeridgian or even of the Oxfordian ;
sometimes to the Upper Jurassic and the Lower Cretaceous, between

1 Prof. Rouillier, Bull. Mose. iv. (1845), even distinguished two ammonitic
zones in his Upper stage, but the characteristic ammonite of the Upper of
these (Ammonites nodiger), not having then received a specific name, was called
Ammonites, sp.

[Zo face p. 548.

LATION OF THE R

BovULoGNE AND NortTHERN REGION SouTH-EASTERN

oscow.
M SoUTHERN ENGLAND. OF ENGLAND. FRANCE.

shales. Sands and sand Tealby Limestone, | Beds with Hoplites
with plant-rei Hythe and Sandgate beds B of Speeton. Deshayesi and

shayesi. Sparrow Hills Beds. Hoplites Deshayesi, Acanthoceras Mar-
rowo, Klin. Belemnites brunsvi- tint.

.
Aannnaan

it

Quart, Journ. Geol. Soc, Vol, LIT.

SYZRAN.

Prrenora REGION.

Anaryr-KurmMysi
ReEaron.

|
CORRELATION

SIMBIRSK,

OF THE RusstAn AND Wurst Evropran FORMATIONS.

Moscow.

RIASAN.

Norruern AND WESTERN GERMANY.
(Supposed sequence of the Ammonitic zones.)

Bovroeye anp
Sournern Exeianv.

|
|

ft
t

|
Clays and shales.

Nortnern ReGron
or ENGLAND,

| bilis.

etc.

Volga, etc.

lites).

gula

Black micaceous clays
with Cardioceras
alternans, Belem-
nites breviawis, etc.

Black micaceous clays

with Cardioceras
alternans and Be-
lemnites breviaris.

Clays and shales. Clays and sands. Sinds and sandstones Clays and marls, Tealby Limestone, |! Beds
Asa ; } i with plant-remains. Hythe and Sandgate beds B of Speeton Deshayesi
TAN, Hoplites Deshayesi. Hoplites Deshayesi. Hoplites Doshayesi. Sparrow Hills, Tata- Hoplites Deshayesi, Belemnites brunsvicensis. Beds. Hoplites Desha ein ¥; eee a 7
rowo, Klin, Black shales, poor in Belemnites ee 2 tint. ea
fossils (traces of censis ei Wee
= = en dae Be ay ] plants), not defined t
% | paleontolopicallys —_ i ae ae 7
eR Black clays. "nt rmer presence Black clays. Black clays. Perruginous sandstone. fermmginous sands 1
62 4 ‘ rae fi rage eat : ae | : and clays with bands GeO ore
8:3 4 | Simbirskites versico- cated by the occur- | Simbirskites versico- | Simbirshites versico- | Simbirskites discofal- of limonite. Traces | Simbirskites discofalcatus, Decheni, téins- P i Barcéunt
BE 3 lor, S. discofaleatus, RETR OLMT EO ree lor, Astarte por- lor, discafaleatus, catus, progrediens, of a marine fauna. bergensis, Hosii, progrediens (developed Atherfield Clay. Simbirskites speeton- ne ng
eS Tnoceramus aucella, versicolor in the recta, Ce ees Decheni. principally in the western half of the ensis,Decheni, disco- || Macroscaphites Tva i,
Rony rt rift ens, ramus F e ion). : a
BAS Drift. aucolla, Waeeanes German Neocomian region) SLalcatis, progre- Oricceraminis
a see diens, _Belemnites
=) por nada, Jjaculum,
8 | Claxby Ironstone (
is = : ane :
3 a | Sands with Belem- ac | ; 2 : per part),beds D,upper Hauterivien. —
rat} cs) nites subquadratus | Glauconitic clays, phos- } | Hoplites vadiatus, regalis, amblygonius, part, C.-C), of Speeton. 3
a 2 (ammonites were not phatie and calcare- } oxygonius, Belemnites pistillirostris, Hoplites radiatus, L
A & found). ous sandstones (with | | Ammonites _regalis, poldinus, Holcodis:
a S Belemnites sub- | | amblygonius, rotula, cus incertus,Astieria |
SI quadratus, lateralis, | | | Astieri, Belemnites Atherstoni. ee
= Aucella volgensis, ae TT Ee a se = | Jaculum.
piriformis, Keyser- | rt eartae ee eee
a Phosphatie conglo- lingi) not subdivided }
8 merate. into zones. | Sand with nodules of Claxby Ironstone(lower
By : E . | phosphatic sandstone. Weald Clay, part), D,, lower part, Valengien.
= | Polyptychites Keyser- | The ammonite-fauna | : : Polyptychites Keyserlingi, bidichotomus, : D, of Speeton,
S Uingi, gravesiformis, seems to indicate | Ammonites Keyser- Olcostephanus latissimus. Hastings Sands Hoplites —neocomien:
x sS Beani, Belemnites three zones :— | lingi, gravesiformis, | Polyptychites Keyser- sis, Roubaudi, Asti-
4 3 lateralis, subquadra- | (1) Ammonites _ con- | hoplitoides, neoco- and Clays lingi praesent pela ios itt 4
aS § tus, Aucella pirifor- | necting the Polypty- | miensis. : Beani,” Belemnites Orb.) ‘Bel Ve
5.4 %& | mis, crassicolis. chites and Simbirsk- Fis i|| eee | aia d'Orb.), Belemnites
oe ites fauna. = 2 aaa oa tate z |
Vat 2 (2) ROH piaielates Key- | Phosphatic aud ferru- | Glauconitic sand and
shy serlingi, gravesifor- ginous conglomerate. | sands e. “)
ae 2 dite ae eee BaUk is Di a tone ae. un, Spribyeiuatone (part : ah
So 2 (8) Ammonites cf. | Ammonites _ stenom- | | sis, aft acenontenaDL gee “Marecus 3 sie pers ef energies pe) ee ;
Rn = Ammonites cf. spass- stenompl alts, Spass- plalus, Marcousa- Hoplites me ie pe ie , J usa the ower Creta- Aniniaates atone NER P|
~ kensis, Belennites kensis, etc. nus, Belemnites sub- sanensis group, B : lus, Aucell, 'P L. “ . sale
= lateralis, subquad- quadratus, Aucella ee ee ieee ey Botan) ;
& eS, q i TGR, FRCORE lemnites lateralis, gensis, Keyserlingi, Grotei. {|
= ratus, Aucella vol- ie J russiensis, Aucella Belemnites lateratis.
oS gensis, Keyserlingi. NS volgensis, Keyserlingi.
2 | Micaceous sand with | Phosphatic sandstone.
ce | nodules of phos-
e | phatic sandstone. Hoplites riasanensis,
g Aucella Pischeri,
s Hoplites riasanensis, trigonoides, Belem-
‘ E Calcareous sandstone. plant-remains. nites mosquensis. Upper Tithonian Gs
| & Ammonites kashpuri- a cect and Lower | ‘
A cus, subelypeiformis, Tebpgak ileal Een)):
lS subditus, catenula- Phosphati lome- | Sandstones and sands. | Phosphati dst pe ee * . .
» oC phatic conglome ands. osphatic sandstone Hoplites Calisto.
BS tus, Belemnites late- rate and sandstone. with Ammonites ig ae ra
es pee HL Tit : 5 : ‘ Spilsby Sandstone(part wasensis, Perisphinc-
qs ralis, russiensis, mos- Ammonites nodiger, kashpuricus, subcly- of), beds D,-D, of tes transitorius.
Oe quensis, Aucella Ammonites subditus, subclypeiformis, ca- peiformis, and glau- | Speeton ta :
me Fischeri, etc. Genes neatmalains, CAE, subditus, conitie ne wath ] :
Ly elemnites russien- elemnives mosquen- mmonites subditus, | y ii i
= sis, AucellaPischeri. se russiensis, Au- catenulatus, ful- } Se subditus,
iS TN ee ee Bean Ou) Hresh wat beds of the Upper Jurassic :
2 = = Purbeck, Serpulit, Miinder Mergel, Eim-
a | beckhiuser Plattenkalk.
3 Glauconitic sandstone. Sand and sandstone | Glauconitic and ferru- eck hae : Portland Stone. Tithonian zone of
% || with large ammo- ginous sands with Perisphinctes geron,
& | Large ammonites of nites of the gigan- Ammonites Blakei, } Ammonites giganteus, colubrinus, Phyllo-
ry the giganteus-type. teus-type. Devillei, and large bononiensis, Blakei, ceras ptychoicum.
Sil ammonites of the Trigonia gibbosa.
& giganteus-type. |
2 — =
5 | Phosphatic nodules | Phosphatic conglome- | Black sandy clays and | Glauconitic sand and Portland Sand and Coprolite Bed.
S) . | Phosphatie conglome- and shales with rate, clays and phosphatic nodules. phosphatic nodules Hartwell Clay of
% 3 || vate and shales. Ammonites virgatus shales. with Virgatites vir- | England. Portland | Belemnites absolutus,
Ae | very poorly repre- Virgatites virgatus, gatus, Belemnites | Clay between La fragments of ammo-
2 2 |\Virgatites virgatus, sented. Virgatites virgatus, Belemnites absolu- absolutus, etc. in | Créche and Wime- nites of the Virga-
Ce ise Belemnites absolu- Belemnites absolu- tus. some places reduced reux, France. tites-ty pe.
Ee | tus, ete. tus. to a thin band of E 2
a 1S ||) phosphatic nodules. Virgatites scythicus, Zone of Oppelia litho-
a Ostrea expansa,Car-
4 | dium morinicum. graphica, i
Bt |
S / ceras cyclotum.
Shales and clays. Shales with Aucel/a | Shales and clays with Shales and clays, Probably destroyed, Sands, clays, and shales| Bituminous shales.
a Pallasi and crushed Aucella Pallasi and and represented only with Ammonites
3 | Belemnites magni- ammonites of the crushed _biplicate | Belemnites magnificus, by the Lower bed of portlandicus, Blei- | Belemnites magnificus,
“3 |) fieus, Aucella Pal- biplicate type. ammonites. Discina latissima, phosphatic nodules Beds with Ammonites portlandicus, Ober- cheri, Trigonia Pel- Aucella Pallas,
8 7asi, crushed ammo- Aucella Pallasi, with Aucella Pal- region der Virgulaschichten. lati, Discina latis- Discina latissima,
8 nites of the Blei- crushed ammonites lasi, Ammonites | sima, __ Belemnites Lingula ovalis,
S cheri-type. of the Bleicheri-| Pallasi, d’Orb., ete. magnificus. crushed _ biplicate
ital, type. ammonites.
Marly clays. Glauconitic sands and | Marly clays with | Marly clays with | Destroyed almost en- | Beds with Hoplites | Clays and shales with | Beds with Hoplites
Kruering- clays with Hoplites Hoplites pseudo- Hoplites pseudomu- tirely (rare finds of Beds with Pteroceras Oceani, Hxrogyra pseudomutabilis, eu- Hoplites pseudo- pseudomutadilis is—
TAN, Hoplites pseudomuta- subeudowus. mutabilis, eudoxcus, tabilis, Cardioceras Kimeridgian Hop- virgula. dowus, Hogyra vir-| mutabilis. pidaceras goa

. t
a
e
e it
‘
n
i ’
‘
i
.
“y
‘
4
4 ‘
y
‘
a
’
‘
’
,

aes tie . a v » ort oe 4
i Pac, eran Wie hea aa mi

i tne

Vol. 52.] STRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 549

the Kimeridgian and the Upper Neocomian: and sometimes it
was held to be entirely Neocomian. Under these circumstances, it
appears to me advisable to avoid this term altogether, the more so
that all the beds heretofore included under it have now been
relegated to their natural place in the general classification, which
is the Upper Jurassic. It was for the above reason that I found
it necessary to introduce in my former work the provisional name
‘Série Speetono-russe’ for the beds overlying the Kimeridgian
and terminating with the zone of Polyptychites Keyserlingi. (See
p. 532 in Bull. Soc. Imp. Nat. Mosc. n. s. vol. v. 1891, or
p- 174 sep. cop.)

Il. On ton EncruisH AND GERMAN SPECIES oF AUCELLA.

The casts of the English specimens of Aucella to be described
were in part obtained by me during my visit to the Woodwardian
Museum at Cambridge in 1888, and in part were sent to me with
the ammonites described in my work on the Speeton fauna, through
the kindness of Prof. T. M*Kenny Hughes, F.R.S. The German
specimens and casts I owe to the kindness of Prof. A. von Koenen,
of Gottingen, of Herr O. Weerth of Detmold, and of the Rev.
Pastor Denkmann of Salzgitter.

The representatives of the genus Aucella have been found in
England at two different horizons. The lower of these is the Lower
Portlandian bituminous shale of Central England (Upper Kimeridge
shale of English geologists), from which have been obtained some
specimens of Awcella Pallasi now preserved in the Woodwardian
Museum. Two of these specimens are figured in my paper, ‘ Juras-
sique supérieur et Crétacé inférieur de la Russie et de l’Angle-
terre, * and I have nothing further to add to my former description
of them. Those which occur at the higher horizon are dealt with
in the following notes.

Avcetta voreEnsis, Lahus., ‘ Ueber die russischen Aucellen,’ Mém. du
Comité géologique, vol. viii. no. 1 (1888), p. 38, pl. i. figs. 1-17.

The English form (Pl. XXVII. figs. 1a, 16, 1¢) corresponds
well with the characters of this species established on Russian
specimens, and from any large collection of such specimens it
is not difficult to pick out individuals in all respects similar to the
English form, so that it is impossible to doubt the identity of the
Russian and English species. In Russia, Aucella volgensis is most
abundant in the zone of Ammonites stenomphalus and A. Marcousanus
—that is, in the lowest zone of the boreal Neocomian. The English
specimen is preserved in the Woodwardian Museum at Cambridge.
It bears the old label ‘ /noceramus imbricatus, Lower Greensand,
Donnington,’ and its matrix shows that it has been obtained from
the Spilsby Sandstone. This form seems to exist also in Germany,

1 Bull. Soe. Imp. Nat. Moscou, n. s. vol. iii. (1889) pl. iii. figs. 4 & 5, p. 106
(p. 48 in sep. copy).

Se ee eee eer eee

590 PROF. PAVLOW ON THE CLASSIFICATION OF THE [ Aug. 1896,

I have two specimens apparently belonging to this species, but too
badly preserved to be identified with certainty. They come from
the Maria Grube at Steinlach.

AUCELLA VOLGENSIS, var, RADIOLATA. (Pl. XXVILI. figs. 2a 26.)

In oultine this is very like the typical Aucella volgensis, but is
distinguished by the feebly marked longitudinal streaks which
intersect the more marked concentric folds. A feebly pronounced
longitudinal hollow in the back part of the larger valve may also be
noted as characteristic of this variety, though less constant, as
appears from Russian specimens. In the Woodwardian Museum ~
collection this specimen was labelled as follows :—‘ Jnoceramus
imbricatus, Bean MS., Donnington, Lower Greensand’: it is in a
Spilsby Sandstone matrix. In Russia this variety occurs at the
same horizon as the preceding form. Judging from some fragments
of Aucella that I have obtained from Eheberg, near Oerlinghausen,
the existence of this variety in Germany is probable.

Avcetta Kerysertinet, Lahus., ‘ Ueber die russischen Aucellen,’
Mem. du Comité géologique, vol. vill. no. 1 (1888), p. 40,
pl. iv. figs. 18-23.

The English specimen of this species (Pl. XX VII. figs. 3a, 36, 3c),
from the Woodwardian Museum, has the shell preserved, and can
be defined with certainty. It bears a label: ‘Claxby. Tealby
Series. Jnoceramus imbricatus.’ The matrix is Claxby Ironstone.
In Russia this species is very numerous in the zones of Ammonites
stenomphalus (Lower Petchorian). In Germany it is also far from
rare. I have seen many specimens of it in the Gottingen Museum,
in the collection of the Rev. Pastor Denkmann at Salzgitter, and
in the collection of Herr O. Weerth at Detmold. The German
specimens are very fine; they come from the Maria Grube
at Steinlach, near Salzgitter, and from Kheberg, between Oerling-
hausen and Bielefeld. This seems to be the commonest species in
Germany.

AUCELLA TEREBRATULOIDES, Lahus., zbid. p. 39, pl. iv. figs. 1-9.

In the Woodwardian Museum a specimen of this species is
preserved, which in size and sculpture is very like that figured by
Prof. Lahusen in pl. iv. fig. 2, op. ct. I have not figured this
specimen.

Beside the above, in Germany other species occur—for instance,
Aucella (Avicula) teuteburgensis, Weerth, which differs from all the
species above mentioned. In another note I propose to give my
opinion concerning this species and its relations to the other forms
of Aucella.

The presence of identical species of Aucella in England, Germany,
and Russia more closely connects the corresponding beds of these
countries, as will be seen below.

le

Vol. 52.] | 8TRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 551

III. Generat ConsrpERATIONS.

Let us now, by the light of these results, glance at the course of
geological events in our region during the final stages of the Jurassic
epoch and the beginning of the Cretaceous.

In Kimeridgian time over Eastern and partly over Central Russia
there existed an extensive sea, communicating with the West
European Kimeridgian sea and stretching to the east and north-
east far beyond the boundaries of Europe.’ In this basin were
developed certain ammonites, appearing in the West European sea
as ‘cryptogenic’ types.” The fauna of the Russian Kimeridgian sea,
though possessing a general resemblance to the West European
fauna, exhibits many peculiarities of its own, as, for instance, the
abundance of the belemnites of the Magnifict and Explanati-groups,
the abundance of Cardioceras (C. subtilicostatum, C. Volge) and the
presence, though rare, of Aucella.

In Centra] Russia, at the end of the Kimeridgian age, the sea
disappeared, and there occurred a certain amount of destruction of
the Kimeridgian beds,’ but in Eastern Russia a further evolution and
migration of faunas took place, and the ammonites of the Bleicheri-
group came into existence (derived probably from the Kimeridgian
Perisphinctes), and Belemnites magnificus, Troslayanus, and explanatus
appeared as the descendants of Belemnites Owen, Panderi, and brevi-
axis of the previous period. In Western Europe the fauna of this
sea, separated for a time by a tract of land, evolved some peculiar
characteristics, and there appeared certain cryptogenic ammonites in
it, such as Ammonites portlandicus (gigas). With the beginning of
the Virgatites epoch, a new ‘ hydrocratic’ displacement of the shore-
lines brought the sea again into Central Russia and even farther into
Poland, and there was a communication between this Russian sea
and that of the West European Bononian, and apparently also that
of England. In this manner we seek to explain the presence of
Virgatites in the Portlandian of Boulogne, the presence of Aucella
Pallasi in the Lower Portlandian (Upper Kimeridgian of English
authors) shales of Spilsby, and the presence of the fragments of
Virgatites and Belemnites, cf. absolutus in the Lower Coprolite-bed
of Speeton.

The physical conditions of the region remained without great
change in the succeeding age of Ammonites giganteus, but the
Aucelle seem to be absent or very rare at this time in Western
Europe, probably owing to some conditions unfavourable to their
existence or to the presence of some inimical forms of animal life in
this region.

In the northern part of England an interruption of sedimentation

1 Witness the Auceli@ in the Kimeridge Olay of the Volga region and of
the Petchora region, and certain faunistic affinities between the Kimeridgian
Hoplites of Eastern Russia and some of the ammonites of Tibet.

* Neumayr, ‘ Ueber unvermittelt auftretende Cephalopodentypen im Jura
Mittel-Europa’s,’ Jahrb. d.k.-k. geol. Reichsanst. vol. xxviii. (1878) p. 37.

* Hence the occasional discovery of Kimeridgian Hoplites in the Portlandian
phosphatic nodules and in the Boulder Clay.

Q.J.G.8. No. 207. 2p

052 PROF. PAVLOW ON THE CLASSIFICATION OF THE [ Aug. 1896,

seems to have taken place at this time, during which the Virgatites-
beds were destroyed so as to leave only a band of phosphatic
nodules, with fragments of Virgatites and Belemnites.

At the end of the Jurassic period in the region of Southern
England, Northern (and Central) France, and Northern Germany
well-marked ‘ geocratic’ movement took place, and, as the result
of this, the Purbeck continent arose and separated the northern
(Aquilonian) from the southern (Tithonic) Sea. This event, how-
ever, did not occur simultaneously throughout this large region ;
the German part of it seems to have. emerged earlier than
the rest, probably at the beginning of the virgatus-age. Some
parts of Russia (the southern part of the government of Nijni-
Novgorod and the northern part of the government of Simbirsk)
likewise emerged approximately at the same time, and remained
dry land until the epoch of the Lower and (in some places) of the
Upper Neocomian ; but no freshwater beds were deposited there.
In other parts of Russia the sea did not disappear until later (at
the catenulatus-nodiger age), and reappeared in Upper Neocomian
time (Simbirsk).

In the district of Syzran there is a region where the Aquilonian
beds seem to pass, without any noticeable break, into the Lower
Neocomian (Petchorian), the beginning of which is marked by the
appearance of new ammonites of the stenomphalus-group. Last
of all there is a region in Russia where the first traces of the
submergence of the Purbeck continent at the end of Aquilonian
time (in some localities, it would seem, at a somewhat earlier time)
can be observed, and this event is marked by the sudden appearance
of ammonites of the Hoplites riasanensis-group amidst the typical
Aquilonian fauna in the governments of Riasan and of Moscow.
But that was only a short and local episode in the life of this fauna,
and soon afterwards a boreal Lower Neocomian fauna with ammo-
nites of the stenomphalus-group (Aucella volgensis, A. Keyserlingt,
Belemnites subquadratus, etc.) coming from the east and north-east
took possession of the Riasan region.

At the same time—that is, a little later than in Central Russia—
the Lower Neocomian boreal sea stretched over Germany, where
it accumulated the lowermost beds of the Neocomian with Ammo-
nites Gevritanus and A. Marcousanus and penetrated to Central
England (depositing the beds with Aucella volgensis, A. Keyserlingt,
Ammonites stenomphalus). This seems to be the first zone laid
down after the partial disappearance of the Purbeck continent
of Western Europe. The next zone of the boreal Neocomian, that
of Polyptychites Keyserlingi, gravesiformis, Beani, etc., possesses
avery wide extension—from Yorkshire and Lincolnshire, through
Germany and Central Russia, far into the North-east. In Central
Russia this zone bears a very well-marked littoral character, being
represented by sands and conglomerates, and being in some places
absent. During the deposition of this zone, but apparently not until
towards the end of it, and therefore much later than in Central
Russia, we find in England, and probably in Germany also, the

YVol.52.] STRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 553

first traces of a new ‘hydrocratic’ displacement of the shore-lines,
by which a further part of the Purbeck continent disappeared and
communication with the southern sea was opened. Thus were the
first pioneers of the southern fauna permitted access to the Northern
basin ; and in the succeeding zone of Hoplites regalis this fauna
took possession of the region and supplanted the Northern species.
There still remained, however, a considerable portion of the pre-
existing continent, and this formed the Wealden land-area. Now
let us consider what had happened meanwhile in the Eastern
Russian part of our region.

As the Table (facing p. 548) shows, the Petchorian beds are over-
lain in Russia by the Upper Neocomian (Simbirskian) beds with
Simbirskites versicolor, discofalcatus, Dechent, ete., and in no part of
Russia are the beds with Hoplites regalis known. We may conclude
from this that by the time when the ‘ hydrocratic’ movement, which
began in Central Russia, had reached the western portion of Europe
and had opened there a communication between the northern and
southern basins, Central Russia itself had once more become dry
Jand, and remained so until Upper Neocomian times, at which
period, in consequence of renewed ‘ hydrocratic’ movements, an
extensive sea again covered North-eastern, Eastern, and in part
Central Russia. In England and probably in Germany, during
the same Upper Neocomian epoch, a boreal fauna regained the
advantage over the southern invaders, and beds with Simbirskites
speetonensis, Decheni, subinversus, etc., were deposited. It is, more-
over, interesting to note that precisely at this period a few forms
of Simbirskites—the characteristic representatives of the boreal
fauna—penetrate far to the south and appear amidst the southern
fauna in the Crimea and even in Southern France. During the
succeeding stages of the Aptian and of the Gault a common fauna
of mixed character establishes itself widely, but in Western Europe
we observe in it the predominance of southern forms, such as
Acanthoceras Martini, Belemnites minimus, and other allied species,

results due probably to a new ‘ geocratic’ displacement of the shore~

lines in Central Russia, and to the rising of Aptian dry land, on
which the plant-bearing sands and sandstones of the Sparrow Hills, of
Tatarowo, and of Klin (government of Moscow) were accumulated.

From this sketch it becomes apparent that the ‘ hydrocratic’ and
*‘ geocratic’ movements of the shore-lines did not take place simulta-
neously over the whole of this vast area, but that each movement
passed slowly through the region latitudinally. And it is this
great march of movements—whether of solid crust or of sea-level it
matters not—that has brought about the complicated sequence of
the different faunas in the different parts of the region above
described. Whence it follows that only by taking into consideration
the course of events over the whole of the region can we hope to
obtain a general and intelligible picture of this particular chapter
of geological history in any country which formed part of it. It
is, however, only on the results of detailed local studies that any
successful attempt to classify the events must be based.

2Pr2

554 PROF, PAVLOW ON THE CLASSIFICATION OF THE [ Aug. 1896,.

I am well aware that the present is a vague and incomplete:
sketch of the subject, but it may serve to turn the attention of my
co-workers to the places and questions especially interesting from
this point of view, and thus lead in the future to a more satisfactory
grouping of the geological events of the period. From a broader
standpoint it shows, too, how in different countries the subdivisions-
of a series of beds may replace one another in regular sequence,
allowing us to follow out the ever-changeful development of the
earth’s surface from one epoch to the next.

EXPLANATION OF PLATE XXVII.
[The figures are all of the natural size. ]

Figs. la, 16, le. Aucella volgensis, Lahus. Lower Greensand, Donnineton..

2 a, 2b, Aucella volgensis, var. radiolata, Lower Greensand, Don-
nington.

3a,36,3¢. Aucella Keyserlingi, Lahus. Tealby Series, Claxby.

2

9)

All the specimens are preserved in the Woodwardian Museum at Cambridge.-

Discussion,

Mr. Strawan remarked that this paper was of especial value at-
the present time, for English geologists had so far failed to
establish a satisfactory separation of the Jurassic and Cretaceous:
systems. The correlation of the North of England with the South
was still a matter of doubt, while even in the classic region which
had furnished the names of Wealden, Purbeck, and Portland the
upper limit of the Jurassic was quite uncertain. The Purbeck strata,
first classed as Oolitic, were transferred by Webster and Fitton
to the Wealden, reinstated as Oolitic by Forbes, and restored to the
Wealden by Topley, while recently, seventy years after the question
first arose, we have been assured by three different observers that
the reptiles, fishes, and plants of the Wealden possess undeniable
Oolitic affinities. Under such circumstances, a communication from
a geologist of the world-wide experience of Prof, Pavlow promises to:
be of the utmost assistance to us in arriving at the most suitable
grouping.

Mr. Treat said that he was sure that all present reguetied the
absence of the Author. He could not discuss the paper, but he
should like to give expression to the pleasure which he had felt in
listening to it. Papers dealing with comparative stratigraphy of
wide areas were rare at the Society, and he thought that the present
one would therefore be cordially weleomed. He had not previously
met with the terms ‘ hydrocratic’ and ‘ geocratic,’ but they seemed
to him of great value. He had often felt the want of such terms.

Mr. Lampiuen expressed the extreme gratification that he felt at
being made the medium for conveying this important paper to the
Society. Whether the proposals of the Author with respect to the
classification receive general acceptance or not, there could be no
doubt of Prof. Paylow’s qualifications for the task, and the infinite

Quart.Journ.Geol.Soc.Vol .LIL.PLXXVII.

F.H.Michael.lith. Mintern Bros imp.

AUCELLA VOLGENSIS
AND AUCELLA KEYSERLINGI.

‘Vol, 52.] STRATA BETWEEN THE KIMERIDGIAN AND APTIAN. 555

‘pains that he had taken in acquainting himself with the details of his
subject in every part of Europe. It was entirely beyond the power
of the speaker to discuss the broader bearings of the paper, and he
ould only approach it from a more or less insular standpoint.
Moreover, certain criticisms which had suggested themselves to him
when the paper first reached his hands, and which he had commu-
nicated to Prof. Pavlow, had been very satisfactorily answered by the
Author in a letter which the speaker had before him. Yet he must
admit that, before finally accepting as the division between the
Jurassic and Cretaceous a line so locally inconvenient as that now
proposed, which split the Spilsby Sandstone and the Zone D of Speeton,
he preferred to await the result of further research. Not to speak of
the uncertainty still existing in some parts of Europe, very little
was at present known respecting the Infra-Cretaceous rocks of the
Middle and South of England, and their relation to those found
north of the Wash, and it was his hope that sooner or later he
might be able to follow up the Lincolnshire work recently commu-
micated to the Society by investigations farther south, where some
elements of the Speeton fauna certainly existed. The recognition
of the presence of the Aucelle in Lincolnshire was important. He
thought that similar fossils existed at Speeton, but in an inferior
state of preservation. He believed that a careful study of the
lamellibranchiata would bring out many other points of interest in
‘the fauna in England.

5906 DR. C. §. DU RICHE PRELLER ON GLACIAL [Aug. 1896,

33. GractAL Deposits, PreciactAL VALLEYS, and INTERGLACIAL
Laxz-Formations i Supatprne Swirzertanp. By OC. SBS.
Dv Ricut Prewier, M.A., Ph.D., F.G.S., F.C.S., A.M.I.C.E.,
M.J.E.E. (Read March 11th, 1896.)

ConTEnTs.

Page
TE, Anbroduction ga teetenee ce ccehraccmnsss oc woes comaumenasenn cama 556.

II. Characteristics and Origin of Cavernous Nagelfluh or
Nubal pmewMDVeckensehOtter .s......c-wwssacneseetmpeeeeraee 557
TID. tGlacial Weposite tre. eel acicl se lace eeccsocmanseoe este ereceee 560°
EV. Preglacial Subalpine Valleys ......1.cses<du otters scent eer 574:
V. The Origin of Subalpine Lake-Basins ...........-...0e000+ 580
WAS }CONC STON Merry. cicses avececn fs oo onsn'nsnaeeeont see eee eee 584

I. InrRopucttion.

In a paper which I had the honour of reading before the Society

last session,’ as well as in another previously published in the
Geological Magazine,” I described in detail a variety of glacial
deposits near the lakes of Constance, Ziirich, Zug, and Thun, in-
cluding several of those extensive and remarkable accumulations of
glacio-fluviatile conglomerate which are the indirect product of
land-ice and, together with intervening moraine and interglacial:
deposits, afford conclusive evidence of three separate and general
glaciations not only of the Alps, but more or less of the Swiss-
lowlands.

The numerous sections of which I exhibited diagrams, revealed
the apparently singular phenomenon that in the Ziirich district the
older glacio-fluviatile conglomerates generally crown the ridges of
the Subalpine Molasse hills, and the younger gravel-beds occur at
lower levels; while in the Lorze valley near Zug, and in the
Kander valley near Thun, the position is reversed—that is, the-
older gravels, resting in the former locality on glacial clay and
Molasse, and in the latter on glacial clay and Triassic beds, appear’
at the bottom, and are, with intermediate alternations of moraine,.
overlain by the younger series. From this marked contrast, it
might be inferred that at the time of the deposition of the older
gravels, the principal valleys in the last-named districts—that is,.
the basins of the Reuss and Aare,—were already eroded approxi-
mately to their present depth, whereas the Zurich valley was as:
yet non-existent or, at any rate, very imperfectly formed; so much.
so, that if this theory be correct, the oldest gravels, now commonly
called Deckenschotter, must have been deposited as a sheet on a:
Molasse plateau extending practically from the present Zurich:
valley to that of the Rhine.

In the paper read last session, I alluded indeed, although merely

1 Quart. Journ. Geol. Soc. vol. li. (1895) pp. 369 e segq.
2 Geol. Mag. 1894, pp. 27 et segg.

a,

Vol. 52. ] DEPOSITS, EIC., IN SUBALPINE SWITZERLAND. 557

by the way, to the occurrence of Cavernous Nagelfluh or Decken-
schotter ' in the Ziirich valley itself, that is, at a considerably lower
level than the Uetliberg and allied high-level deposits; and as the
question involves the solution of an important problem, I took the
opportunity of examining last summer a large additional number
of glacial deposits throughout that district.* The object of this
inquiry was twofold :—

(1) To ascertain which, if any, of the lower-level conglomerates
must be regarded as the glacio-fluviatile products of the first or
Upper Pliocene glaciation, or whether we must simply and en bloc
accept the view recently enunciated by several Swiss geologists °
that all the lower-level gravels are, without distinction, so-called
Upper and Lower Terrace-gravels—that is, the indirect products of
the two Pleistocene glaciations.

(2) To determine the probable and approximate depth of the
Zirich valley before the deposition of the Deckenschotter—in other
terms, to reconstruct the Preglacial valley as it appeared at the ~
advent of the first glaciation in Upper Pliocene times. In the
course of this enquiry, which has a direct bearing also on the
general Preglacial configuration of the other principal Subalpine
valleys, I was, moreover, led to several important conclusions with
respect to the combination of causes which determined the forma-
tion of the lake of Ziirich, and, in a wider sense, of the other lakes
lying in the same zone at the foot of the Alps.

Il. CHaracteristics AND Origin oF CaveRNous NAGELFLUH
oR SUBALPINE D&ECKENSCHOTTER.

Characteristics—The characteristics of the Subalpine Decken-
schotter consist, according to my observations, chiefly in the
occurrence of the conglomerate in isolated or continuous cliffs of
peculiarly rugged appearance ; in advanced cementation, not merely
by siliceous material, but by calcification; in the occurrence of
partially leached pebbles, and more especially of cavities left by
pebbles which have been either wholly dissolved or have fallen out ;
in the generally noticeable stratification, as well as in the occurrence
of underlying sand as a clear proof of the fluviatile origin of the
deposit ; and, lastly, in the occasional occurrence of striated pebbles
as further proof that, in such cases, the deposit was formed at no
great distance from a glacier.

* Although, as I shall show, the term ‘ Deckenschotter,’ or plateau-gravel, is
not strictly applicable to the Subalpine Cavernous Nagelfluh deposits, both
terms are used throughout this paper as denoting the glacio-fluviatile conglo-
merate which is the indirect product of the first glaciation. The paleonto-
logical evidence of the Subalpine Deckenschotter having been deposited towards
the end of the Pliocene period rests, as already pointed out in my paper of last
session, mainly on the occurrence of Mastodon arvernensis in the analogous
‘alluvions anciennes’ of the Rhone valley above Lyons.

? Prof. T. G. Bonney, in his ‘ Ice-Work’ (London, 1896), published since
this paper was written, truly observes that the Ziirich district is ‘classic ground
in the history of the work of ice.’

3 Notably by Dr. L. Du Pasquier, Beitrige zur geol. Karte d. Schweiz,
vol. xxxi. (1891), and by Dr. A. Aeppli, ibid. vol. xxxiv. (1894).

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Vol. 52.] GLACIAL DEPOSITS IN SUBALPINE SWITZERLAND. 559

Although these characteristics conspicuously distinguish the
Deckenschotter from the older Miocene Nagelfluh, and—as regards
the cliff-like appearance as well as the advanced calcification—also >
from the younger, Pleistocene gravels, the conglomerate varies
greatly according to its position, to its derivation, and to the time
of its deposition within the limits of the first Glacial period. And
this is the more natural when we reflect how many must have been
the glacial oscillations within that time, and that every advance of
the glacier marks a stoppage, and every recession of the same marks
a renewal of erosion at the terminal moraine. If, broadly speaking,
we assume, in accordance with the general periodicity of Alpine
glaciers of our own day, an alternate advance and recession of the
glaciers of the first Ice-period every fifty years, there must have
occurred in the space of, say, 5000 years, at least 100 semi-
secular oscillations, during half of which glacio-fluviatile material
must have been deposited in varying form, at various points, and at
widely-varying levels.

Origin.—As I have already pointed out in previous papers, there
is no room for doubt that the Deckenschotter of the Ziirich district
was, in the main, deposited by streams issuing from an extensive
Linth glacier which, descending from the Glarner Alps, advanced to
within a few miles of the lower Aare valley, and, together with
the Rhine glacier on its right and the Sih] and Reuss glaciers on its
Jeft, formed, towards the end of the Pliocene period, one great
Subalpine ice-sheet.

Although the moraine of these glaciers yielded part of the
material of which the Deckenschotter was built up, the bulk of the
conglomerate was not, in my opinion, transported by the glaciers
from any great distance, but is derived from the enormous accu-
mulations of Miocene Nagelfluh at the foot of the Alps. In
this view I was confirmed by an examination of a large number
of pits and natural sections of comparatively loose, both calcareous
and polygéne, Miocene Nagelfluh in the hills flanking the lake of
Ziirich.’ This youngest Nagelfluh-zone, which corresponds to the
Upper (freshwater) Molasse, extends longitudinally from the Lake of
Constance to that of Thun and transversely as far as the Uetliberg
near Ziirich, and all the rocks occurring in the same are also largely
represented in the Deckenschotter as well as in the younger, Pleisto-
cene gravels ; while the large boulders of Miocene Nagelfinh, which
are occasionally found embedded in the Deckenschotter, are derived
from the coarser and extremely hard conglomerate of the older, 7. e.
the Rigi, Rossberg, and Speer Nagelfluh-zones corresponding to the
Lower (freshwater) Molasse.* Thus the successive deposition of
Deckenschotter and Pleistocene gravels in three series, each of

1 The pits and sections are those near Binz, Pfaffhausen, and Weilerhof in
the hills on the right, and near Riiti and Wadenswil on the left of the Lake
of Ziirich.

2 Strictly speaking, the Molasse and Miocene Nagelfluh formation comprises,
besides the Lower freshwater, Marine, and Upper freshwater series, also the
isolated Marine beds of the so-called Red (Oligocene) Molasse,

560 DR. C. 8. DU RICHE PRELLER ON GLACIAL ~——[ Aug. 1896,

which was pushed farther out into the Subalpine valleys, resolves
itself, in my view, mainly into a retransport, by glacio-fiuviatile
agency, of Miocene fluviatile material deposited in three mighty
zones, one in front of the other, at the foot of the Alps.

III. Guacrat Deposrrs.

In briefly describing the salient features of the various additional
‘glacial deposits examined in the Ziirich district, and extending over
an area more than 40 miles in length, it will be convenient to
begin at the lowest point, namely, at the confluence of the river
Limmat with the Aare near Turgi, and thence proceed up the
valley. The various deposits are marked in the map of the district
(fig. 1, p. 558).

Turgi. —This locality is undoubtedly one of the most interesting
in the Swiss lowlands, for it is here that the three principal rivers
of Central Switzerland and main affluents of the Upper Rhine must
have converged ever since Subalpine valleys were formed. As is
shown in the sketch-map (fig. 2), there are high-level deposits of
Deckenschotter at two points of the trough which marks the
confluence of the three rivers—namely, on the two spurs called the
Gebensdorfer Horn and the Siggenberg at the extreme end of the
Limmat valley,’ to the former of which I have already referred in a
previous paper. These deposits are each about 60 metres in depth,
very similar in character, and rest direct on Molasse without inter-
vening moraine, the contact being on the Gebensdorfer Horn at
contour 480 (metres), while on the Siggenberg it is at contour 550, or
70 metres higher. In the trough itself, where the mean river-level
coincides with contour-line 330, the gravels deposited by the three
rivers are so interming!ed that it is extremely difficult to define their
derivation, except that the Aare pebbles, having travelled a longer
distance, are generally much smaller than those of the Reuss and the
Limmat. At any rate, all the gravels at this point belong to the
younger series, and, with the exception of some isolated blocks, the
repeated powerful re-erosion at the junction of the three rivers has
apparently left no vestige of Deckenschotter.

Baden.—The peculiar feature of this locality consists in a re-
markable anticlinal Jurassic fold called the Laegern, which, tra-
versing the Limmat valley almost at right angles, rises to 856 metres
above sea-level, and towers fully 200 metres above the surrounding
Molasse hills. In this saddle, a trough or basin with a steep,
narrow, V-shaped passage for the river at each end, has been scooped
out by fluviatile action, and it is in this basin that several ex-
tremely interesting glacial sections are exposed.

As is seen from the sketch-map (fig. 2), the lowest of these
sections occurs close to the edge on the left bank of the Limmat at
contour 360, near the lower end of the basin, and a few hundred
metres beyond the sharp bend of the river where the sulphur

1 According to Dr. Du Pasquier (op. czt.), there is a cap of Deckenschotter

also on the Bruggerberg, an isolated, oblong-shaped hill on the left bank of
the Aare.

:
;
b

Vol. 52. ] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 561

springs of Baden issue from fissures between the Keuper and the
Liassic strata. The horizontally stratified conglomerate forms a
cliff about 34 kilometre in length, and juts out at intervals from
loose gravel and boulder-bearing moraine, which is banked up
against it and fills the Baden basin to a depth of about 20 metres.
A large artificial cave excavated in the conglomerate and a pit
close by in the loose gravel and sand reveal a marked difference
between the two deposits, the former being, in my view, a remnant.
of Cavernous Na-
gelfluh which es-
caped erosion,
while the latter
contains small

lumps of the older \S
conglomerate, a

™
and must therefore Som
be the younger SA ‘ f

deposit of the two.
The Nagelfiuh,
which is about 6
metres in depth,
rests on about 1
metre of sand, and
this again rests
on marl and gyp-
sum of the Keuper
formation. At the
side of a road
above the cliff just

\
co

=i

are

SSN
Ws

{susng winy pup vapyg oy) fo dnyy—Z “Siz

mentioned, there >
is another rem- aoe
e

nant of the same > my) oe
conglomerate, ae ae
“ie elS}s 5

and similar rem- ad eee
i « ~I3]o0 2

nants are buried HIS13 a
Sis iaa

probably at other aS ie
points of the PRS not
Baden basin; at Q
Q

all events, several
others conspicuously project from the vineclad slope of the gravel-
and-moraine terrace between Baden and Turgi. This conglomerate
exhibits all the characteristics of Deckenschotter and, in my opinion,
must be regarded as such.

Another remarkable section of Deckenschotter occurs on the hill
on the left side of the basin, near a point called Eichthal, close to a
sharp bend of the high-level road from Baden to the Gebensdorfer
Horn, and at contour 480. The exposure (fig. 3, p. 562), in which
a large artificial cave has been excavated, exhibits an exceedingly
hard, compact, irregularly stratified conglomerate about 6 metres in

For ‘ Lautfohr’ in fig. 2 read ‘ Lauffohr.’

62 DR. C. 8. DU RICHE PRELLER ON GLACIAL = [ Aug. 1896,

depth, mixed in its upper portion with boulders reaching the size of
a man’s head, and passing into about 2 metres of moraine, on which
are stranded several enormous blocks of calcareous and polygéene
Miocene Nagelfluh, measuring about 3 x2 x1 metres, namely from
10 to 15 tons in weight. In its lower portion, the conglomerate
‘shows irregular, somewhat oblique stratification, and numerous dis-
integrated pebbles, while many of the larger, often subangular
pebbles, as well as the boulders in the upper portion, exhibit ice-
‘scratches. This upward passage from glacio-fluviatile to purely
glacial deposit therefore marks a period of transition, in other words,
-an oscillation of the glacier.

Fig. 3.—Section at Eichthal, near Baden,

Miocene Nagelfluh blocks
5 tons spent seep lata Yi

aig, A 2 Wy
peo) No Sieg Y, 2 oraine
ERP an In

: ow: 222 SOUR: Ons BV

by

oy)

30

M42
7
4

Li,
f= day sx CAs
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IRS SIZ Ley

—————— — SR

——

Ca a Ma ee

Not less instructive, although of a more complex character, is an
exposure on the opposite, that is, the Ennetbaden or right side of
the basin, on the Ehrendingen road which skirts the slope of the
Laegern. In this quarry, conspicuously situated at contour 412, or
about 60 metres above the Limmat, is exposed a cliff of obviously
very old, but, owing to disintegration, somewhat brittle conglo-
‘merate, about 15 metres in depth, banked up against the Jurassic
strata, and containing in its upper portion a number of natural
caves left by large well-rounded Miocene Nagelfluh boulders about
2 metres in diameter, which have gradually fallen down, and now
encumber the floor of the quarry. The Nagelfluh is irregularly
overlain and partially covered by morainic material mixed with
Jurassic detritus, while in front of it—that is, in a pit excavated
close to the road and at a lower level than the gravel floor—appears
a younger, much more sandy conglomerate composed of much
fresher pebbles. This later gravel, which was evidently banked
up against the Deckenschotter cliff, reappears lower down the road
and is excavated near the junction of roads at the upper end of the
basin.

A fourth exposure examined in the Baden basin is that situated
at contour 467, under the shelter of a Jurassic knoll called Guggen-
buhl, below the village of Hertenstein, near the lower end and on
the right side of the basin. The two pits, facing each other, form
part of a larger deposit and are excavated to a depth of about
5 metres; in both cases there are 3 metres of stratified, not
very compact, conglomerate resting on about 1 metre of sand and

Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 563:

passing in its upper, coarser portion, into 1 metre of morainic
material. The transition-zone contains numerous striated pebbles
and boulders, and, as is universally the case in Alpine glacial
deposits, it is the dark grey limestone which takes ice-scratches
and impressions of all kinds more readily than any other rock.
The conglomerate is scarcely hard enough to be genuine Decken-
schotter, and contains, moreover, small lumps of the latter. Hence
it must be regarded as being the product, not of the first, but of
the second glaciation. At any rate, the deposit clearly marks a
glacial oscillation, and it is on this account that it is of special
interest.

Even putting aside the last-named, somewhat doubtful, deposit,.
we have thus in the Baden basin distinct and conclusive evidence of
Deckenschotter at three different levels—that is, close to the river
at contour 360, and on the slopes of the hills at each side of the
basin, at contours 480 and 412 respectively.

Wettingen.—The next important occurrence is about 3 kilometres-
above Baden, near the Convent of Wettingen above the sharp curve:
described by the Limmat, which is here crossed by two railway
viaducts. Beginning under the upper viaduct at contour 370, a
cliff of very compact conglomerate about 6 metres in depth runs for
a distance of a few hundred metres up the river along the left bank,
jutting out at intervals from the younger gravel and overlying
moraine. Exactly under the viaduct and about 10 metres from the
left abutment, the Molasse, which here appears about 2 metres above
the river-level, has a slight but distinct dip up the valley, while
the Nagelfluh cliff which directly overlies it dips in the opposite
direction (fig. 4). The vineclad slope of the opposite bank of the

‘a Pin
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i » Z 1

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7

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: eth sutta= stig Molasse
an) 8!

a | ee — 7 —_
er — sw = —_ — SS
eS 362 m.above
River Limmat sea-level

river, composed of loose gravel and moraine, is likewise marked by
several projecting remnants of the same conglomerate, in con-
spicuous contrast to the loose gravel, which, in a pit reaching down
to the river’s edge, is irregularly overlain by moraine. The
occurrence at Wettingen therefore presents features precisely
analogous to that of Baden: the phenomenon of the younger
deposits covering and being banked up against the old con-
glomerate is manifest in both cases. To the left of the Convent of
Wettingen lies the Deckenschotter deposit of Teufelskeller, already

564 DR. C. 8. DU RICHE PRELLER ON GLACIAL _[ Aug. 1896,

described in previous papers, and on the right side a small cap of
the same conglomerate on an isolated hill called the Sulzberg. Thus
the Deckenschotter appears at three points across the valley, the
contact with Molasse being at the two extremes approximately at
contours 470 and 480, and in the valley at contour 362.

Between the Teufelskeller deposit near Baden and that of the
Uetliberg near Ziirich, several ledges of Deckenschotter occur on the
upper slope of the broad Molasse ridges locally called Heitersberg
and Hasenberg, the conglomerate being overlain by moraine of the
second glaciation to a depth varying from 50 to 100 metres, while
the opposite or Altberg ridge, between Sulzberg and Ziirich, has
apparently been entirely denuded of all evidence of the first
glaciation, even the younger moraine overlying the Molasse being
of insignificant thickness as compared with that on the ridge of the
left side of the valley.

Killwangen and Wiirenlos.—Returning now to the Limmat valley
and proceeding from Wettingen upward, we come, at a distance of
about 4 kilometres, to the remarkable moraine-wall of Killwangen,
which I described in an earlier paper as marking the limit of the
third glaciation. Near the village of Wiirenlos, on the right side of
the valley, there is, in a large and conspicuously situated sandstone
quarry, a very striking and clean-cut exposure of moraine overlying
the Marine Molasse to a depth of 6 metres. The moraine, in which
are embedded large boulders of Miocene Nagelfluh and Sernifite,
shows that the glacier travelled over the Molasse without in the
slightest degree disturbing the latter, much less eroding it. This
moraine deposit, occurring, as it does, at least 1 kilometre in
advance of the terminal moraine of Killwangen, must, in my
opinion, be regarded as belonging to the second and not to the third
glaciation.

Limmat Gravel-beds.—The Killwangen moraine-wall rests on
the so-called ‘ Limmat gravel,’ which is the fluviatile product of the
second glaciation. Dr. Du Pasquier has been led to regard all
the valley-gravel and overlying moraine below Killwangen and as
far as Turgi as the product of the third glaciation: that is, as con-
stituting the glacis or ‘ Gletscherboden ’ of the Linth glacier of
that Ice-period. It is, perhaps, somewhat hazardous thus to draw
a hard-and-fast line between the two Pleistocene gravels in the
Limmat valley. The glacier of the third Ice-period, after stopping
at, and receding from, Killwangen, remained probably for a long
time stationary at the lower end of the present Lake of Ziirich, as is
evidenced by the belt of moraine-walls so characteristic of that
city. On Dr. Du Pasquier’s theory, it would therefore follow that
all the gravel-beds between Ziirich and Killwangen were deposited
during that second stoppage, and are consequently the product of
the youngest or third glaciation, whereas they undoubtedly belong
to the older Pleistocene series, since the Killwangen moraine-wall
distinctly overlies them. The material derived from the Zurich and
Killwangen moraine must therefore have been deposited on the
older gravel and moraine, and was by subsequent denudation in

ee

Vol. 52. ] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 565

great part or entirely removed, and carried beyond Turgi into the
Aare and Rhine valleys. On these grounds, the whole of the
younger gravels as well as the overlying thin coating of moraine in
the lower Limmat valley must, in my opinion, be regarded as, in
the main, the product of second glaciation, and as having probably
been deposited during the recession of the Linth glacier of that
period. The cliffs and other remnants in situ of old conglomerate
projecting from that gravel and moraine, and embedded in the
valley at Baden and Wettingen, afford conclusive proof that, at the
time of the deposition of that old conglomerate, the floor of the
valley was already in existence. The great difference of level
between the Cavernous Nagelfluh or Deckenschotter deposits on the
ridges of the Molasse hills and those at the bottom of the valley
seem, at first sight, to point to subsequent erosion on an enormous
seale ; but, in my view, the high-level deposits were formed during
the maximum extension of the Upper Pliocene Subalpine ice-sheet,
which, filling the valley and spreading over the hills on both sides,
probably reached to the lower end of the Baden basin, while the
low-level deposits were formed during the recession of the glacier
when the latter had already shrunk considerably, and was itself
embedded in the valley.

Héngg.—About 11 kilometres from Killwangen, on the right side
of the valley, below the village of Hongg, and close to the road, a
conspicuous exposure or cliff of Cavernous Nagelfluh partially
excavated occurs at contour 420, about 30 metres above the present
river-level. The well-cemented, but coarse, indistinctly stratified
conglomerate, about 7 metres in depth, rests on sand, and is
overlain by about 2 metres of moraine and talus. The presence of
numerous scratched pebbles shows that it was deposited not far
from the glacier, but the overlying moraine, which has left it
eutirely undisturbed, is a younger deposit, probably of the third
glaciation. The conglomerate must, in my view, be regarded as
Deckenschotter, and this is confirmed by a pit about 100 metres
lower down on the same road, where a much looser younger gravel,
interstratified with sand and overlain by moraine, is exposed. The
phenomenon already noticed at Wettingen and Baden, of younger
gravel being banked up against a remnant of older conglomerate, is,
therefore, observable also at Hongg, the younger gravel being, like
the extensive gravel-beds at the bottom of the valley, the product of
the second glaciation.

Kissnacht.— Passing over the typical Deckenschotter deposit of
the Uetliberg, as well as the more recent deposits in the immediate
vicinity of Ziirich already described in previous papers, the next
locality of interest is on the right shore of the lake, about 5 kilometres
above Ziirich, in the Kiissnacht ravine, deeply eroded in glacial
deposit and Molasse by the torrent or Tobel of the same name. In
the upper part of this ravine, about 4 kilometres from the lake,
several cliffs of Cavernous Nagelfluh crop out from the moraine by
which the Molasse is covered to a depth of 50 to 100 metres. At
one point on the left bank of the torrent, and at contour 520, one of

566 DR. C. 8. DU RICHE PRELLER ON @LAcIaL = [ Aug. 1896,

these cliffs is accessible, the section here exposed being shown in
the diagram, fig.5. The extremely compact, but in some parts:

Fig. 5.—Section in the Kissnacht Ravine.

talus ard. Bx OS
Moraine; ON MAGE
SSX SUN
By

SS
Decken> ounger
schotte pi gravel
and sand
ee
Se cs
Hilo 2508 if LZ
StH A ZE
Molasse— i aan

—

Ie _ © cose ==
aN EE
SSS —_ te
SSS

Bee eae

disintegrated and brittle conglomerate, about 20 metres in depths
dips up the valley at an angle of no less than 40 degrees, and
against it are banked, at its upper end, several alternations, each
about 1 metre in depth, of younger stratified sand and gravel.
dipping in the opposite direction. Ina small pit, a few hundred
metres farther up the ravine and at about the same level, there
appears, in superposed layers of 2 metres each, fresh sand and gravel
overlain by moraine with large boulders, this deposit being evidently
part of the same deposit as the younger sand and gravel in the other
exposure. The moraine which overlies the gravel in both these
exposures exhibits the irregular, mound- and knoll-shaped contours
so characteristic of the moraine of the third glaciation. The
contact of the Cavernous Nagelfluh with the Molasse, near the edge
of the torrent, is buried under gravel detritus, although the Molasse
appears immediately below and above the deposit; but at a short
distance higher up the ravine, the torrent, whose bed is throughout
encumbered with erratic blocks of occasionally enormous size,*
flows no longer on Molasse but on glacial clay, an additional proof
of the great age of the upper part of this valley. The Molasse
strata in the lower part show a gentle but very distinct dip up the
ravine; it would, however, be hazardous to infer that the steep
reverse dip of the Cavernous Nagelfluh is the result of the same
displacement by earth-movements. At all events, the various
phenomena described warrant the conclusion that that conglomerate
ean only be Deckenschotter, while the gravel banked up against it
is the product of the second glaciation.

1 The largest of these erratic blocks in the Kissnacht ravine is, according to
my measurements, 3X 3X3 metres, equal to 60 tons in weight, and bears the
name of ‘ Alexanderstein,’ in memory of the late Dr. Alexander Wettstein,
who described the Kiissnacht ravine in his ‘Geologie von Ziirich, etc., 1885,
and a few years later lost his life on the Jungfrau.

Vol. 52. | DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 567

Au.—About 9 kilometres from Kiissnacht, but on the left side
of the lake and close to the shore, is situated the peninsula of Au,
entirely composed of glacio-fluviatile gravel, the origin and the age
of which have long been a fruitful source of discussion. Escher
yon der Linth and others regarded it as of Tertiary age and con-
temporaneous with the Uetliberg Nagelfluh—that is, pre-Glacialfin
the old acceptation of the term; while latterly, among others by
Dr. Aeppli,! it has been classed with the Low Terrace, namely, the
Pleistocene gravels of the third glaciation. In the paper read last
session, I mentioned it incidentally as probably being a detritus-
cone deposited by the river Sihl during the older Pleistocene or
second Interglacial period, but a close examination of the locality
has led me to modify this view. The peninsula (fig. 6) forms an
oblong dome-shaped cone
rather less than 1 kilo- Fig. 6.—Section at Au.
metre in length and
about 50 metres in depth,
the summit being at con-
tour 456, while the mean
lake-level is at contour
409. All along the edge
of the lake-level, but
more especially at the
western end, and facing <---== ; ee
the lake, there appears a Eig wee
cliff with both natural Moawnasiie i ite
and artificial caves, of
hard, compact, and irregularly stratified conglomerate from 5 to
15 metres in depth, many of whose pebbles, varying in size up to
that of a man’s fist, are leached and disintegrated and show traces of
former crushing and other impressions. In one exposure, where the
stratification is clearly marked, a stratum of sand 5 metres thick is
intercalated between the Cavernous Nagelfluh, and the whole
deposit has a dip up the valley of about 20°, which is, however,
due simply to its deposition as a detritus-cone, and not to earth-
movements. At another point the Cavernous Nagelfluh is covered
by a looser and coarser gravel, largely composed of rough and very
imperfectly rolled pebbles of Sernifite, evidently deposited subse-
quently and by a stream flowing transversely over the conglomerate
into the lake. Ina farm-shed near the summit of the peninsula,
at contour 445, one of the walls, 12x4 metres, is formed by
gravel also dipping up the valley and composed, in upward
succession, of 1 metre of sand containing pebbles, 2 metres of
very coarse and loosely cemented gravel in which are embedded
boulders up to 1 metre in diameter, and 1 metre of loose, some-
what less coarse gravel. This is obviously, like the Sernifite-bearing
gravel lower down, a much younger deposit than the conglomerate
of the cliff bordering the edge of the lake, the latter being, i in my

YC

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Beitrage z. geol. Karte d. Schweiz, vol. xxxiv. (1894) p. 94.
Q.J.G.8. No. 207. 2a

268 DR. C. 8. DU RICHE PRELLER ON GLACIAL = [ Aug. 1896,

view, Deckenschotter, while the former, which constitutes the upper
portion of the peninsula, is probably the indirect product of the second
glaciation. The contact of the old conglomerate with the Molasse
is not disclosed, but is probably some 20 metres below the level of
the lake, which near this point attains its maximum depth of about
142 metres. The occurrence of Deckenschotter on this quasi-
promontory, and even below the lake-level, is, at first sight, ex-
tremely puzzling; but the phenomenon admits, in my opinion, of an
adequate explanation, namely, that the submerged Molasse-floor of
the present peninsula was originally, that is, before the first glacia-
tion, at a higher level; that on this Molasse-floor the Deckenschotter
was deposited during the recession of the glacier ; that during the
following Interglacial period it was, by erosion, reduced to an island
which shared the general subsidence of that part of the valley, as I
shall show farther on; that the superposed younger gravel, which
also filled the gap between the island and the mainland, was
deposited during the recession of the glacier of the second Ice-
period, and that the gap was re-eroded after the third glaciation,
the island thus reconstituted being, by subsequent alluvial deposit,
again connected with the mainland, and assuming the form of a
peninsula, as it appears at the present day.

Albishorn.—On the Albis range, which flanks the left side of the
Zurich lake- and Sihl valleys, and extends from the Uetliberg to the
Albishorn, the Molasse is generally overlain by moraine and an
abundance of erratic blocks of the second or maximum glaciation ;
but above and below this moraine there occur, more especially near
the southern end, various deposits of glacio-fluviatile conglomerate,
of which those of the Albishorn and Biirglenstutz may serve as
typical examples. Below the inn on the summit of the Albishorn,
which is at contour 915, or 45 metres higher than the summit of
the Uetliberg, a spring issues at the contact of the Deckenschotter
and the underlying impervious, boulder-bearing, glacial clay. The
latter can be traced some distance down the brook, but its contact
with the Molasse is indistinct and lies somewhere near contour 850.
The cliff of well-cemented, coarse, and horizontally stratified Caver-
nous Nagelfluh which overlies the glacial clay is about 5 metres
in depth. The pebbles, occasionally striated and coarser at the top
than at the bottom, are, however, remarkably fresh, and the con-
glomerate, although obviously Deckenschotter, differs from the
Uetliberg deposit just as much as the latter differs from that of Au,
in striking confirmation of my former conclusion that the difference
observable between various deposits of this conglomerate is not of
kind, but of degree. Upon the Albishorn Deckenschotter rests, to
a depth of about 15 metres, a much looser conglomerate, in which
scratched pebbles, as evidence of the proximity of the glacier, are
numerous, and which, moreover, contains small lumps of the old
conglomerate ; while farther on, towards the end of the range, the
same gravel overlies an extensive exposure of loose surface-moraine
about 20 metres in depth. On both sides of the Albishorn inn
the Deckenschotter crops out at various points of the narrow ridge,

Vol. 52.] DEPOSIIS, ETC., IN SUBALPINE SWITZERLAND. 569

from the gravel and moraine-detritus under which it is generally
buried. We have, therefore, at the Albishorn clear evidence of
Deckenschotter, which, even at this high level, is overlain by
moraine and gravel of a younger glaciation.

This is strikingly confirmed by an even more instructive exposure
near the summit of the Biirglenstutz, which latter is situated about
2 kilometres from the Albishorn towards the Uetliberg, and, being
at contour 918, is the highest point of the Albis range. The Molasse
appears here near contour 850, or practically at the same level as on
the Uetliberg and Albishorn, and is overlain by about 25 metres of
horizontally stratified, typical Deckenschotter, upon which follows
glacial clay and moraine to a depth of about 15 metres; and this,
in its turn, is overlain by about 25 metres of much looser and
irregularly stratified gravel, which closely resembles the upper gravel
on the Albishorn.

Altschloss.—One of the most remarkable deposits of Deckenschotter
is that of Altschloss, on the hills above Wadenswil on the left side
of, and about 1 kilometre from the lake, and near the Burghalden
station of the Wadenswil, Einsiedeln, and Goldau railway. The
exposure, which is shown in the diagram (fig. 7) in longitudinal
section, consists of three separate, originally connected cliffs of
extremely hard conglomerate, and the cliffs are crowned by the
ruins of the feudal castle of Altschloss, built, like the surrounding
wall and a bridge, entirely of this conglomerate. The identity of

Fig. 7.—Section at Altschloss, near Wadenswil.

Longitudinal Section

colour and the almost imperceptible passage from the natural to
the artificial structure produce the exceedingly striking effect of
the whole being one solid mass, and the perfect preservation of the
dressed blocks about 1 metre square attests the even more than
usual hardness of the conglomerate. The cliffs are about 10 metres
in height, and one of them contains a large cave, where sand appears
at the bottom of the horizontally stratified conglomerate. The cliffs
form part of a larger deposit which extends also to, and crowns, the
neighbouring hill of Gehren, and to the orphan asylum above
Wadenswil, as is evidenced by several cliff-like outcrops. The
contact of the Deckenschotter with the Molasse is obliterated by
detritus, talus, and vegetation; but several springs which collect
the water at the bottom of the conglomerate show the contact to
be at about contour 550, while the summit of the Altschloss cliffs
is at contour 570. In my view, the Altschloss deposit shares with
2Q2

570 DR. C. 8. DU RICHE PRELLER ON GLAcIAL [Aug. 1896,

that of Au the peculiarity of being situated in a zone of subsidence,
with which I propose to deal farther on.

Schindelleggi.—This locality derives especial interest from the cir-
cumstance that here the river Sihl was deflected from the drainage-
area of the Ziirich valley by enormous accumulations of glacial deposit,
of which there are several remarkable exposures. As is seen from
the sketch-map (fig. 8), the junction of the Sihl with its two
affluents, the Biber and the Alp, is about 2 kilometres above
Schindelleggi, although the points of confluence have evidently beem

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Fig. 8.—Map of the Schindelleggi District.

Wadenswil * .
@ = Deckenschotter

Altitudes in Metres.

repeatedly barred and shifted in the course of successive glaciations..,
Above the confluence, all the three rivers flow parallel to each other
and to the strike of the Alps, through flat, broad, and very ancient
valleys, subsequently filled to a considerable depth with glacial and
fluviatile deposit ; while below the confluence, as far as Schindelleggi,
the Sihl has eroded its present bed deeply in moraine, the Molasse
only appearing again at the point of deflection near that village.
Even in that section, however, the river does not now run in its-

Vol. 52. | DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 571

original bed, which lay probably in the direction indicated in the
sketch-map by a dotted line (fig. 8). Of this, proof is afforded by
a. remarkable exposure at Kaltboden, on the left bank of the present
Sihl, about 1 kilometre above Schindelleggi, close to the railway and
road leading to Hinsiedeln, As is shown in the diagram (fig. 9),

Fig. 9.—Section at Kaltboden, near Schindelleggi.

“7 = =
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‘the section exposed in the large pit at contour 320, about 10 metres
in depth, consists in its lower part of alternating layers of fine
gravel, sand, and clay, dipping in opposite directions, and overlain by
3 metres of moraine followed by 2 metres of talus. With the excep-
tion of a little adventitious Sernifite, the gravel is mainly composed
of yellow and grey limestone- and sandstone-pebbles, upon which no
ice-scratches are observable, while the moraine contains striated
boulders from the size of a man’s head to 1 metre in diameter, both the
calcareous and polygéne Miocene Nagelfluh being largely represented,
Below this pit, and on the same slope, along a canal running parallel
to the river at contour 775, another large quarry, recently opened,
exhibits a horizontally stratified section, 20 metres in depth, com-
posed of 7 metres of glacial clay and 10 metres of sand and gravel,
overlain by 3 metres of moraine and talus. The moraine at the top
of the upper as well as of the lower quarry is of the third, the clay at
the bottom of the lower quarry is of the second glaciation ; hence we
have in the lower and upper exposure an extensive Interglacial,
that is, strictly fluviatile delta and superposed detritus-cone de-
posited by the Sihl after the second Ice-period. The floor of the
detritus-cone is probably not much below that of the upper quarry,
as is evidenced by a spring which issues a few hundred metres
higher up the road at contour 824. The extent of these deposits,
no less than the beautifully clean-cut sections, the typical detritus-
cone structure, and, in addition, the absolute flatness of the over-
lying moraine, showing the total absence of any ploughing action of
the glacier, combine to render the two exposures of Kaltboden
among the most striking and instructive of the whole district.

Before the deposition of the Kaltboden delta, and, a@ fortiori,
immediately before the advent of the first glaciation, the course of
the Sihl must have been at a lower level, namely, on Molasse, That

572 DR. C. 8. DU RICHE PRELLER ON GLACIAL §©[ Aug. 1896,

the original outlet of that river was to the Zirich valley is evidenced
by the deep and broad depression eroded between the two mountain-
spurs of Ktzel and Hohe Rhonen, near Kaltboden, as is shown in the
diagram (fig. 10). The ratio of slope of the two mountains places
the Preglacial Molasse-bed of the
river somewhat to the east of the

s Ss S Kaltboden exposure, that is, near
s ae E8 Geissboden, where a sharp reverse
aoe = 3 curve of the Sihl marks the first point
ste §. | of deflection, just below the present.
We: AB | confluence of the Sihl and Alp. The:
Molasse-bed would here probably be

Qo Nes eree Say at contour 700—that is, about 80:
va ri; metres below the present moraine-
A ih bed of the river, and no less than

120 metres below the crest of the
moraine-wall, which now bars the
old outlet. From here to the then

; floor of the Zurich valley the river,
: flowing in the direction of the present

sis bay of Richterswil, must have formed

a rapid, having a fall of about 7 per
cent. (1 in 13), through a narrow
V-shaped valley or ravine, which is.
now deeply buried under moraine,
and probably resembled closely the
Molasse ravine of the present river—
- course between Schindelleggi and
Sihlbrugeg.

A second point of deflection of the:
Sihl from the Ziirich basin occurs at
Schindelleggi at contour 750, where:
the river describes a sharp curve at
an angle of 50°. The entrance of the-
deep ravine at this point, just below
the railway-bridge, is shown in the
transverse section (fig. 11), and presents the peculiar feature that the
left bank is formed by a wall of Lower (freshwater, so-called raised).
Molasse, and the right bank by a moraine-wall 50 metres in depth,
resting, however, on Molasse, as is evidenced by a sandstone quarry..
This moraine-wall, which contains, besides angular blocks, enormous
boulders of Miocene Nagelfiuh up to 3 metres in diameter, and shows.
irregular, but yet distinct divisional lines, marking the superposition
of younger on older moraine of successive glaciations, is a con-
tinuation of the wall at the upper point of deflection near Geiss-
boden, and constitutes the bar thrown across the Preglacial outlet:
by the Linth glacier, which thus deflected the Sihl and its successive
glaciers to the Reuss basin, until that river eroded its present bed.
parallel to, but outside the drainage-area of the Lake of Zurich.
It is hardly necessary to mention that the Sihl glacier-torrent which

Hohe Rhonen, 350 metres above Lake Ziirich.
Glarner Alps
|

ie
LS Gus 1S
TN2 8 tye

“~

4

va Were orn
Cees Vie en
(ine AT Lu CA Baris eee
oa Soll Ota OP i Si)
ie Vs rst Us aa

Fig. 10.—Molasse-depression and moraine-wall between Etzel and

Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 573

deposited the Deckenschotter of the Menzingen plateau and Lorze
valley, already described in a previous paper,' must have flowed at a
much higher level, that is, probably 150 metres higher than the
Molasse-bed of the Preglacial Sihl near Geissboden, or that of the
present Sihl at Schindelleggi.

In the foregoing description
of glacial deposits I claim to

alsuly

have shown: (1) that deposits 2

and remnants in situ of Decken- RF
schotter occur not only on or =
near the ridge of the hills, but Ef

also at the bottom and on
the slopes flanking the Ziirich
valley, notably at Baden, Wet-
tingen, Hongg, Kiissnacht, Au,
and Altschloss, of which the
first four deposits appear re-
spectively at a gradually.ascend-
ing level, while the last two
are now at a lower level than
they were at the time of their
deposition ; (2) that in the first
four cases referred to, younger
glacio-fluviatile gravel, in the
main the product of the second
glaciation, is banked up against
the old conglomerate, and that
in several cases, for example,
at Baden and Wettingen, the
old conglomerate resting on
Molasse, is buried under the
younger gravel, which, in its

/418 4anry

O°
Orne noes “0° Pw) OY ao WIS P)
ZL 10" Ce ea _ .

2 oie . ee aby SA Cd ‘en

; . ce OSD ; :

“ubbajjpopuryoy yp hayoy yyy ayy fo wonoas asvoasup4y— TT *Stiq

turn, is overlain by moraine. ania s
These phenomena lead to the ee

conclusion that at the time SMS

immediately preceding the de- Somes

position of the Deckenschotter 3° =

—in other terms, at the advent s

of the first glaciation, towards

the end of the Pliocene period—the Ziirich valley was already
eroded, the depth of the lower part of the valley being approxi-
mately that which it has at the present day, while the floor of the
upper part of the valley was at a higher level than that of the
present lake, and, as I shall show in the sequel, was subsequently
lowered by a subsidence due to earth-movements.

* Quart. Journ, Geol. Soc. vol. li. (1895) pp. 369 et seqg.

574 DR. C. 8. DU RICHE PRELLER ON cLactaL = [Aug. 1896,

ITV. Preenactat SUBALPINE VALLEYS.

I have already shown in an earlier part of this paper that, so far
as the ice-sheet which covered the Swiss lowlands towards the end
of the Pliocene period can be subdivided, the Linth glacier was, in
the main, confined to the Ziirich valley, while an arm of the Rhine ©
glacier spread even then over the Glatt district north of the Ziirich
basin. The same applies, in my opinion, to the flow of the two
rivers before the first glaciation—in other words, the Glatt valley,
now practically dried up, was originally eroded by an arm of the
Rhine,’ and the Ziirich valley by the Linth jointly with the Sihl,
whose original, but subsequently barred outlet to the Ziirich basin
lay, as already stated, in a line from Schindelleggi to the present
bay of Richterswil.

The erosion of the Ziirich basin as a continuous valley from the
upper end of the present lake to Turgi involved the removal of
two saddles; one, the Jurassic Laegern bar at Baden, and the other
the Molasse and Miocene Nagelfluh saddle which stretched across
from near Richterswil to Rapperswil, as is evidenced by the two low
islands of Ufenau and Liitzelau, which now form a reef obliquely
across the upper end of the present lake, the Marine Molasse and
Miocene Nagelfluh rising just above lake-level. The Baden bar must
have been, in the first instance, sawn through by the backward
erosion of a torrent descending from the Laegern towards the basin
of the Aare, until it was sufficiently lowered to admit the Linth,
which subsequently completed the erosion of the lower valley. The
erosion of the Laegern bar must necessarily have preceded the first
glaciation, because, if it were otherwise, the Deckenschotter deposit
of the Gebensdorfer Horn, situated north of the Laegern, could not
be the glacio-fluviatile product of the Linth glacier. As regards the
Ufenau saddle, the process was probably precisely similar to that at
Baden: that is, the torrent originally descending from it towards
the Zurich basin, and sawing the saddle by backward erosion, was
subsequently superseded by the Linth. On the other hand, unlike

1 The theory that the Glatt valley was originally eroded by the Linth, and
the Zurich valley by the Sihl, has been advocated by Wettstein and by Prof.
Heim (‘ Geologie v. Zurich, 1885, and Neujahrsschrift Naturf. Ges. Ziirich,
1891), while Dr. Du Pasquier (Beitrage, vol. xxxi. 1891, p. 122) favours the pre-
sumption that even the Rhine Valley, from the Irschel hills to the confluence of
the Aare near Waldshut, was originally eroded by the Linth. In my view, these
two rivers are much too small to have eroded such broad valleys. The drainage-
areas of the Sihl, Linth, and Rhine at Schindelleggi, Walen Lake, and Sargans
respectively, are about 200: 600: 4200 sq. kilom., and, at a rainfall of 2 metres
per annum, less 25 per cent. for absorption, yield respectively 10, 30, and 210
cubic metres per second, the proportion being, therefore, 1:3:21. Ifwe assume
that one-third of the volume of the Rhine was deflected at Sargans to the west
(while the main arm flowed N.N.W. through the Constance basin, and thence
towards the Danube until deflected to the W. towards Schaffhausen), we have an
adequate flow for the erosion of the present Walen Lake fjord, the Glatt valley,
and the Rhine Valley from Irschel to Waldshut by the western arm of tke
ancient Rhine, and a sufficient volume for the erosion of the Ziirich valley by
the combined Linth and Sihl.

‘Nol. 52. | DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 579

the narrow Baden defile, which, near the apex of the two V-shaped
passages, is even now not more than 30 metres in width, the valley
at the lake-level near Ufenau is at least 3 kilometres broad, and
hence the removal of the old saddle cannot be attributed solely to
the erosive action of the Preglacial Linth, but must be, in part,
the effect of a subsequent subsidence of the old valley-floor, as will
appear in the sequel.

Proceeding now to the reconstruction of the Ziirich valley
(figs. 1 & 12, pp. 558, 577) as it appeared at the advent of the first
glaciation, we have to trace the lowest points at which the solid
rock appears, as marking the old valley-floor, especially where the
rock is directly overlain by Deckenschotter.

Beginning at the confluence of the Limmat and Aare, near Turgi,
we find the solid rock practically at river-level on the left bank of
the Aare at Lauffohr, exactly at the junction, that is at contour 332.
Thence proceeding up the Limmat valley, we strike it again for
about a hundred metres at the river-level about halfway between
Turgi and Baden, at contour 340; then at Baden, near the lower
end of the basin, at contour 351; and again at Wettingen, near
the lower and upper viaducts, at contours 358 and 362 respectively,
both the Lower Baden and Upper Wettingen exposures being, as
already shown, directly overlain by Cavernous Nagelfluh. The first
section of the old valley-floor thus has a fall of 30 metres in 8°5
kilometres, or 3°5 metres per 1000, equal to 1 in 286, or roughly
1 in 300. If we assume this as the uniform fall also for the upper
sections, the old valley-floor was near Héngg at contour 412, a few
metres lower than the Deckenschotter exposure described, and about
15 metres above the present river-level; near Ziirich at contour 433,
or 24 metres higher than the present lake; near Kiissnacht at
contour 451, or 42 metres higher than the lake, and about 50 metres
lower than the Deckenschotter deposit in the Kiissnacht ravine ;
near Au at contour 483, or 74 metres above the present lake-level ;
near Altschloss at contour 500, or 91 metres higher; and near
Richterswil—that is, on a level with the Marine Molasse bank of
Wollerau—at contour 518, or 109 metres above the present lake-
level, the distance of this point from Turgi being 52 kilometres.
The Marine Molasse bank of Wollerau, at contour 518, marks the
confluence of the Preglacial Linth and Sihl, and therefore approxi-
mately also the then level of the passage already eroded in the
Ufenau saddle, whose highest points, namely, Ufenau and Liitzelau,
must, however, have been as yet at a higher level. If, proceeding
from this point upwards, we assume the gradient of the Preglacial
Linth valley to be the same as in the lower sections, the floor at the
junction of the Linth and western Rhine valleys near Wesen, or the
present Walen Lake (distance 25 kilometres), must have been at
contour 605, or 182 metres above the present level of that lake,
while at Glarus, or 10 kilometres farther, it was at contour 640,
that is, 159 metres higher than the present valley-floor at that
point. The same gradient prolonged from Wesen for a distance of
30 kilometres through the Walen lake-basin to Sargans, the point

576 GLACIAL DEPOSITS IN SUBALPINE SWITZERLAND. __[ Aug. 1896.

of bifurcation of the two arms of the Preglacial Rhine,’ would
place the valley-floor at that point at contour 710, or 190 metres
higher than the present valley. As regards the Sihl valley, its
Preglacial course from the old confluence with the Linth near
Wollerau to Schindelleggi and upward has already been dealt with
in a preceding part of this paper.

In the profile (fig. 12), plotted from the various altitudes given
in the preceding paragraph, I have inserted at their respective levels
the different low-level occurrences of Deckenschotter in the Zurich
valley between Turgi and the junction of the Preglacial Linth and
Sihl, near the old Ufenau bar. From the contours already given, it
is seen that the inclination of the ancient valley-floor is by no means
arbitrarily chosen, but corresponds more or less closely to the
gradually ascending level of those Deckenschotter exposures, that
is, to their contact with the underlying solid rock, except the deposits
of Au and Altschloss, which, as already mentioned, lie in a zone of
subsequent subsidence. Moreover, having regard to the meandering
and irregular course of the river, the fall of 3:5 per kilometre of the
valley-floor corresponds to only about half, that is, to 1°75 kilometre,
or about 1 in 600 of the river, whose mean velocity, in a shallow
section of about 200 square metres, would not exceed 4 metre
per second, or about 1 mile per hour. At this velocity the erosion
on the convex side of one bend of the river would be approximately
balanced by re-deposition of material on the concave side of the next.
Under these conditions the Linth, immediately before the first glacia-
tion, must have been essentially a sluggish river, the more so as its
course was not regulated as it is at the present day. Of such
ancient windings the Ziirich valley offers numerous examples, one
of the most striking of which occurs at Wettingen and Baden, where
the river has repeatedly changed from one side of the valley to the
other, the present curved course being the exact reverse of a former
one, which I have indicated by a dotted line in the sketch-map
(fig. 2, p. 561).’

In the profile (fig. 12) of the Preglacial valley-floor, I have
further plotted (of course, only diagrammatically) the salient points of
the Molasse crest-line on both sides of the valley. This crest-line,
having been in many places buried under successive glacial deposits,,
which were in part again removed by subsequent denudation, has
not, since the advent of the Ice-age, undergone any very marked
changes as regards its general elevation, and therefore enables us,
in conjunction with the old valley-floor, to determine the con-

1 The low alluvial.saddle near Sargans, which now separates the Rhine from
the Walen lake-basin, is only 5 metres in depth and about 5 kilom. in width.
In the year 1817 the Rhine nearly overflowed again into the Walen lake-basin.
In order to meet this contingency, the railway along that lake to Sargans and
Ragatz was not allowed to cross the bar by a cutting, but had to pass over it.

2 Similar changes in the river-course were, no doubt, produced also in Glacial.
times, when, during a recession of the glacier, the glacier-stream was banked by
the terminal moraine-wall, until it overflowed the latter at the lowest point or
effected a breach at the point of least resistance.

Fig. 12.—Profile

24004 1 5
of the Ziirwch 2300
Valley (Lammat 2200+ Pregl, .
“ 21001 Valley =
and Lnnth). 2000 |. Floor Miseren
7900
7800
1700 £9 & & ” dD oa ee
4600 3 Se) oe. 3 8 se 8 Sos
o Ean Bovis 22 £5 28 ‘
1500 S £5 8 < a ee SBS $2 s
& =a A oO or = = 2 ~
_ 1400 aS = oS = ees as 2 eS
= 1300 o 2
~ 7200 S
& © rs
S 7100 S | &
© 1000 < ———~ Upper Sih! Valley ;
> .
= 900 S — o
= 800 Ss SS
$ 7ool ®&
oS) S Preglacial
5 ae R valley-floor
L
400 Wesen
i wu i <— ayes ver ams ZED, rey ALE ELK | Wal
800 eco a lll UW, CeLRY a os ter < =a ny NM sSetetereu Ht Mh, y ~~ Pe ; iss a a
are ie Mini Yi, LT LEN : ‘
sci a Filled ap Lower Lake Present Middle Lake Basin
ea-leve ‘ie
Kilom,

Kilom.

5718 DR. CU. 8, DU RICHE PRELLER ON GLACIAL = [ Aug. 1896,

figuration and depth of the Preglacial valley by transverse sections.
Of such transverse sections I have plotted no less than twenty, from
which I have deduced a mean section for each of the three divisions
of the Zurich valley, covering in the aggregate a distance of over 50
kilometres, as follows :—

kilometres.

(1) Turgi (confluence of the Limmat and Aare) and Baden...... 6°5
(2) Baden (upper end of basin) and Ziirich end of present lake... 22°5
(8) Ziirich and Wollerau, or Ufenau bar (Preglacial confluence

OL Taira MOS UI) aa eme reise se ssa esis tc'ov » oinkina'elefoweresie neta nelle 22°5

Again, from these divisional mean sections I have deduced a
general mean section, both the former and latter being shown in
the diagrams (figs. 13, 14, 15, & 16), and drawn to an uniform
‘horizontal and vertical scale. As is seen, the old valley widens and
deepens gradually from its lower to its upper end, and the general
mean section gives a width between the crest-lines of about 7 kilo-
metres and a depth of 300 metres,’ the general ratio of slope being
5°, equal to 8°7 per cent., or 1 in 11°5, while the vertical dip, or
proportion of depth and upper width, is 1: 23, and the cross-section
of the valley therefore represents an extremely flat curve.

If we compare this valley with two contiguous old valleys—namely,
that of the Glatt, eroded by an ancient arm of the Rhine, and
that of the Reuss—we find that they all present the flat dome-shaped
ridges and the correspondingly shallow depressions which are
eminently characteristic of all Molasse valleys eroded by large
rivers. ‘The Albis or Uetliberg range, dividing the Ziirich and Reuss
basins, is the only one whose Preglacial dome-shaped configuration
has been profoundly altered by the Postglacial erosion of its right
flank by the Sihl, and of its left flank by the Reppisch, in conse-
qquence of which the original dome was converted into a A (inverted
wedge-shaped) central ridge, with a low ridge on each side.

1 The totals of the calculation are as follows, the sections being considered
as flat parabolas, according to the formula 2 sh.

Upper width. Depth. Length. Cubic contents,
s h
metres. metres. metres, cubic metres.
J. 2 (2210 x 157) x< 6500 = 1503 million.
II. 2 (4820 x 191) x 22500 =) 13809
Til, 29700 x 400) x 22500 ==) D899 ieee
51500 TOouL ees

Hence the mean section is 1,427,000 sq. m., the mean width 6°6 kilom., and the
mean depth 323m. In round figures, the total quantity of material removed
‘by erosion for about 50 kilom. may therefore be taken at 70,000 million cubie
metres, the mean section at 1,400,000 sq. m., and the mean width and depth
at 7 kilom. and 300 m. respectively.

= SE

OT a ae

Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 579

It is on the ancient flat and broad ridge which, at the advent of
the Ice-age, extended continuously from the Albishorn to the
Uetliberg, Baden, and the Gebensdorfer Horn,’ that the various
deposits of old conglomerate were formed during the first glaciation ;
and seeing that they occur at irregular intervals, each of them
marks, in my view, a stage in the general but intermittent recession
of the ice-sheet. As regards the evidence of the Preglacial floor
of the lower Aare valley, whose course along the foot of the Jura
lies, moreover, in a natural synclinal channel between that range

TRANSVERSE SECTIONS OF THE ZitRIcH VALLEY.

Fig. 13.—Lauffohr to Baden.

[Width=2-21 kilom. ; depth=157 metres. ]

Fig. 14.—Baden to Zirich.

i ae eel
[Width=4°82 kilom.; depth=191 metres. |

Fig. 15.—Zurich to Ufenau.

ee ee

[Width=9°7 kilom.; depth=400 metres. ]

Fig. 16.—Mean transverse section.

ieee ee

[Width=7 kilom.; depth=300 metres. |
Scale=1 : 100,000.

and the Subalpine Molasse, I have traced the solid rock close to the
river's edge at Brugg, near the confluence with the Reuss, as well
as at Lauffohr, as already mentioned, while, according to Dr. Du
Pasquier, it also appears in many places above Brugg, as well as
at several points between Lauffohr and the confluence of the Aare
and Rhine.

Again, in the last-named valley, both below and above that
confluence, long stretches of solid rock at river-level are mentioned
by the same writer, who is himself led to the conclusion that this
valley was already formed before the first glaciation, the Decken-

* Various small trausverse valleys and depressions were, during subsequent
interglacial periods and in Postglacial times, formed in this ridge by erosion
and landslips; it is, therefore no longer continuous at the present day.

580 DR. C. 8. DU RICHE PRELLER ON GLACIAL [Aug. 1896,

schotter being embedded in thevalley.' A further striking example is
that of the Rhone valley, which Prof. F. A. Forel, in his well-known
work on the Lake of Geneva, conclusively shows to be post-
Miocene, but pre-Pleistocene*—that is, of Pliocene and Preglacial
age. |

There is thus abundant evidence that all the principal river-
valleys of Subalpine Switzerland were, in the main, already formed
and excavated before the advent of the first glaciation.®

V. Tue Oricin of SUBALPINE LAaKkeE-Bastns.

From the profile.of the Preglacial valley-floor, it is evident that
at the advent of the first glaciation the Lake of Ziirich had not yet
come into existence. That its formation is primarily due to a sub-
sidence of the old valley-floor is attested, not only by the great
and unknown depth at which the solid rock lies buried beneath
moraine and gravel near the outflow of the river Limmat from the
Lake of Ziirich, where borings have failed to reach the Molasse even
at 40 metres below the river-bed, but by the gradually increasing
depth of the lake from Ziirich upwards, the deepest point, about
halfway, and not far from Au, being 142 metres below lake-level,
although even here the bottom consists not of solid rock, but of mud
and other lake-deposit overlying the same. From this point the
lake, much filled with moraine and sand, again rapidly decreases |
in depth as far as the old Ufenau bar, where the Molasse appears at
lake-level ; and immediately beyond—that is, on the other side of the
bridge—emerges the old moraine-wall which banked the upper or
_ shallow lake-basin, the Molasse being in this basin again covered to
a great depth by glacial and other deposits. As already shown, the
solid rock appears at the confluence of the Limmat and Aare, near
Turgi, at contour 332, and again near Wettingen, at contours 358
and 362, while the deepest point of the lake lies at contour 266, or
66 and 94 metres lower than the solid rock near Turgi and Wet-
tingen respectively. This remarkable difference of level clearly
points to a subsidence of the old valley-floor for a distance, measured
longitudinally, of nearly 40 kilometres.

On examining the profile (p. 577), it will be observed that the
general crest-line of the hills flanking the Ziirich valley is marked
by two distinct anticlines trending obliquely across the valley and
parallel to the general strike of the Jura and Alps, namely, the

1 Beitrage z. geol. Karte d. Schweiz, vol. xxxi. (1891) p. 103. In another
place (p. 106) Dr. Du Pasquier states that the transverse valleys (e. g. the Aare
Valley), too, must have been already, though imperfectly, formed even in
Miocene times, as is shown by the occurrence of Miocene Nagelfluh.

2 «Te Léman,’ vol. i. (1892) p. 240.

3 T have not dealt in this paper with the Eastern Alps; but there is no doubt
that the Inn Valley above and below Innsbruck is also Preglacial, the old
gravels being deeply embedded in it. This view is also shared by Dr. Du
Pasquier, op. jam cit. p. 106.

‘Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 581

Jurassic Laegern anticline at Baden, and the anticline of the
Albishorn, which trends across the lake between Horgen and Au.
The first of these was obviously formed in Miocene times, that is,
before the first glaciation, and the same applies therefore to the small
eynclinal folds of the Gebensdorfer Horn and Teufelskeller, lying
respectively on the northern and southern flanks of the Laegern
fold. If these synclinal folds were of later, that is, Glacial age,
the Deckenschotter deposits would show conclusive traces of having
shared the displacement of the underlying strata; but, on the
contrary, that conglomerate rests in almost every instance uncon-
formably on the Molasse. Thus, on the Gebensdorfer Horn it
overlies horizontally the Molasse, which dips north at an angle of
about 20°; at Teufelskeller, in the quarry on the northern slope of
the hill, the stratification is likewise perfectly horizontal, while the
slight reverse dip of only about 4° at one or two points of the
southern cliff is more apparent than real, and therefore so doubtful
that any inference drawn from it is devoid of value. Again, at
Wettingen, where the Molasse at river-level has a gentle inclination
up the valley, the Nagelfluh overlying it near the upper viaduct
clearly dips in the opposite direction, and on the Uetliberg, too, as
well as on the Albis range generally, the superposition is distinctly
unconformable. In face of this evidence, it is clear that all the

principal earth-movements in the lower part of the Ziirich valley

took place before the first Ice-period, and not after the deposition
of the Deckenschotter.

Essentially different, however, is the case of the second or Horgen
anticline in the upper part of the valley. From Horgen to Au and
Wadenswil, for a distance of about 6 kilometres and on both sides
of the lake, the Molasse-terraces of erosion exhibit a distinct reverse
dip, which I have also verified in the hills above Au, namely, in the
ravine of a stream descending parallel to the lake, from Riiti to
Wiadenswil, where the Molasse bank is overlain by Miocene Nagel-
fluh. The reverse dip of the terraces of erosion bordering the lake
was first pointed out by Prof. Heim’; and although the inclina-
tion does not exceed 2 per cent. on an angle of about 1°, and
is, indeed, according to my observations, of an undulating rather
than uniform character, the phenomenon is yet of unquestionable
importance, the more so as the maximum dip of the terraces down
the valley is only 0-9 per cent., that is, about 0°5°, or 54, of the
ordinary ratio of slope of the hills towards the lake. Even more
decisive proof of a considerable zonal subsidence, extending from
that part of the Lake of Ziirich across the so-called Hirzel and
Menzingen plateau to the Lake of Zug, is afforded by the greatly dis-
turbed Molasse strata in the Sihl valley, notably about 1 kilometre
above Sihlbrugg, where, close to a sharp bend of the Hirzel
road at contour 550, I have verified a dip up the valley of the
Molasse of no less than 25°. Other distinctly reverse inclinations
of the Molasse occur in the Sihl ravine near Sihlsprung and in

1 Beitrage z. geol. Karte d. Schweiz, vol. xxv. (1891) p. 476.

582 DR. C. S. DU RICHE PRELLER ON GLACIAL = [ Aug. 1896,.

the Lorze ravine north of the stalactite-caves, the dip up the valley
being in these two cases about 1°. It is important to note that
not only at the two points just mentioned, but also at Altschloss,
the contact of the Molasse underlying the Deckenschotter is near
contour 550; that the reverse dip (7. e. 1°) of the terraces of
erosion bordering the Lake of Ziirich is approximately the same
as that in the Sihl and Lorze ravines; and, lastly, that the two
points noticed in those ravines lie, together with Altschloss, in a
line parallel to the strike of the Alps. In other words, this line
marks the syncline of the subsidence-zone, and it is to this sub-
sidence that the Lake of Ziirich primarily owes its origin.

‘As regards the Deckenschotter deposits, the evidence of reverse

dips on and near the Albishorn—indeed, as I have already shown, of
the high-level occurrences generally—is either doubtful, inconclusive,
or directly negative ; and the same applies to the lower-level deposits.
of Au and Altschloss, as well as to those in the Lorze and Sihlk
ravines. ‘The apparent or occasional slight dip of these deposits,
either in one direction or the other, is, in my view, due simply to
their character of detritus-cones, with the exception of one case om
the Hirzel road near the village of Oberkellenholz, where, at con-
tour 647, a cliff of Deckenschotter, crossing that road at right
angles, drops, according to my measurements, at an angle of 23°
for some distance towards the Sihl ravine. Having regard to the
general reverse dip of the Molasse in this region, varying from
1° to 5° and 25°, the inclination of the Deckenschotter cliff just
noticed warrants the inference that the zonal subsidence between
the Lake of Ziirich and that of Zug, and with it the formation of
the Zirich lake-basin, took place after the deposition of that con-
glomerate, probably between the first and second glaciations, and at
any rate in Pleistocene times.

The approximate depth of this subsidence may be determined
from the difference of level between the anticline near the Albishorn
and the syncline already referred to. Although the Molasse strata
of the Albis range have, in places, a dip of as much as 14° down
the valley, the crest-line of the rock, irregularly overlain by glacial
deposits, is practically horizontal, since at both ends, that is, at the
Uetliberg and near the Albishorn, and also midway, the solid rock
appears near contour 850. The difference of level between the
Molasse at the Albishorn and that at the three synclinal points is
300 metres, and this is therefore the approximate maximum depth
of subsidence of the zone between the lakes of Ziirich and Zug, and .
hence also of the old Ziirich valley.’

If the irregularly-shaped glacial deposits, under which the
Molasse of the Hirzel and Menzingen plateau is now buried, could

1 By an elaborate calculation, Dr. Aeppli (Beitrage, vol. xxxiv. pp. 75, 76)
arrives at a subsidence of 425 metres, his computation being based, not upon the
contact-points of the solid rock (obviously the only reliable standard), but upon
the summit-levels of the Deckenschotter deposits, which latter may, however,
have undergone many changes since they were formed. Wettstein (‘ Geol.
Zurich,’ p. 57) and Dr. Du Pasquier (Beitrage, vol. xxxi. p. 116) arrived at about

Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 583

be removed, the configuration of the subsidence-zone between the
two lakes would be that of a flat dome-shaped ridge which, before
the subsidence, was a continuation of the original Albis range, and,
being then 300 metres higher, was practically at the same altitude
as the Molasse of the latter—that is, approximately at contour 850.
It is therefore on this old plateau that the Altschloss Deckenschotter,
now 300 metres lower, was deposited, while that of Au, assuming
it to extend 20 metres below present lake-level (to contour 390), was
deposited at an altitude 207 metres higher, that is, approximately
at contour 660, or on the upper slope of the old ridge.

As is seen from the profile, the Preglacial valley-floor near
Altschloss was at contour 500 and, after the subsidence of 300 metres,
at contour 200. The lowest point of the present lake-bed, com-
posed of lake-deposit, is at contour 266; but the solid rock probably
lies 15 metres lower, namely at contour 251. A line drawn from
contour 200 through contour 251 and thence prolonged, strikes the
Preglacial valley-floor at contour 374—that is, near Killwangen,
about 17 kilometres below the end of the present lake at Ziirich.
Killwangen therefore marks the probable starting-point of the
subsidence of the Preglacial valley-floor, and consequently the
probable lower end of the original lake-basin.

The formation of the lake-basin kept pace with the gradual sub-
sidence of the valley-floor, and was therefore very slow; that is,
the river becoming gradually more sluggish, formed pools, and,
finally, a continuous sheet of water with an outlet at the lower
end. The deposit of the second, and, again, of the third glacia-
tion gradually filled the lower basin, and subsequently a Postglacial
bar, deposited by the Sihl at its inflow into the Limmat just below
Ziirich, defined the present limits of the lake at its lower end.

The phenomenon of similar Postglacial bars is traceable also in
other Subalpine lake-formations. Thus, the Rhine which formed
the Lake of Constance, was probably, in the first instance, barred
by the Danube, and subsequently deflected by moraine-walls
towards Schaffhausen; the Walen Lake, originally connected with
the Lake of Ziirich, was barred by the Linth; the Lake of
Zug by the Lorze, and probably also by the Reuss; the Lake
of Lucerne by the Emme, although here the evidence is not so
clear ; the Lake of Brienz, originally connected with that of Thun,
was banked by the delta of the Liitschinen, while the Lake of
Thun was banked by the Kander; again, the Aare banked the
Lakes of Neuchatel and Bienne, and the bar deposited by the
Arve at its inflow into the Rhone was largely instrumental ir.
forcing the Lake of Geneva back to its present limits. Similarly, in
Savoy, the Lake of Annecy was barred by the Fier, and the Lac

142 and 160 metres as the depth of the subsidence, their calculation being,
however, based simply upon the difference of level between the Molasse near
Baden and the deepest point of the lake, plus the fall of the present valley-floor,
or 0°17 in 100.

Q. J.G.S. No. 207. QR

584 DR. C. 8. DU RICHE PRELLER ON GLACIAL _—[ Aug. 1896,

du Bourget by the Rhone.’ In all these cases, then, a delta and
superposed detritus-cone were thrown across the lake-valley practi-
cally at right angles, and thus the four successive main phases in the
formation of Subalpine lakes of our own day may be summed up as
follows :—fluviatile erosion of the Preglacial valleys; subsidence of
the valley-floors in their upper parts by unequal earth-movements in
the Alps; partial filling of the original lake-basins by glacial and
glacio-fluviatile deposit at both ends; and, finally, restriction of the
lower ends of the lakes to their present limits by fluviatile Post-
glacial bars.

VI. Concrusto0n.

It will be observed that the conclusions at which I have arrived
in this paper differ in some respects widely from the views recently
enunciated by several Swiss geologists. More especially does this
difference relate to the question whether the principal Subalpine
valleys were excavated before or after the first or Upper Pliocene
glaciation.

Apart from the evidence I have adduced, my conclusion that the
first glaciation found the principal Subalpine valleys already eroded
derives substantial support from the very history of the Tertiary
epoch. In Kocene times the Alps had already emerged from the
surrounding sea, though as yet only as a group of low islands.
The Miocene period witnessed the principal thrusting and folding
of the Jura and the Alps; and the products of increased denu-
dation—namely, sand and clay, afterwards hardened to Molasse, and
fluviatile detritus subsequently cemented to compact conglomerate—
were deposited between the two ranges in two freshwater and one
intermediate marine series, the latter being formed in an arm of
the sea which, towards the end of the Miocene period, still reached
from the Mayence basin to the foot of the Alps. The process of
folding continuing, the Subalpine Molasse and the enormous banks
of conglomerate, too, were raised, notably near the Alps; the sea
receded; the lakes formed in the shallow depressions of the Molasse
plateau dried up, and, consequent upon the increased steepness of
the Alpine slopes, denudation and erosion set in on a greatly
enhanced scale; rapids and ravines formed; the great Alpine rivers
effected in the Miocene Nagelfluh walls those breaches which later
on afforded easy and convenient passages to glaciers; and broad
valleys were eroded in the soft Molasse strata of the Swiss lowlands,
the general direction of discharge being towards the natural col-
lecting-channel along the foot of the Jura, and thence to the Rhine.
Thus, the Lower and Middle Pliocene period in Subalpine Switzer- —
land did not witness the deposition of any new rock-formations, but

1 Prof. F. A. Forel (op. cit. p. 246) is disposed to regard even the alluvium
of the River Po as having been instrumental in forming the contour of the
Italian lakes at their lower ends; but the formation of these southern lake-basins
is a much more complex question than that of the lakes at the northern base of

the Alps, and I have refrained from dealing with them in this paper, as they
are outside its immediate scope.

Vol. 52.] DEPOSITS, ETC., IN SUBALPINE SWITZERLAND. 585

was an unbroken period of erosion and denudation on a prodigious
scale. The long duration of this post-Miocene and pre-Glacial
period appears the more obvious when we reflect that it was
contemporaneous with the formation of the extensive marine beds
of the Subapennine hills and of Sicily.

It is a singular fact that the geological epoch which immediately
preceded the appearance of man is perhaps the most difficult to
unravel. But unless we assume that in this post-Miocene and
pre-Glacial period, which Sir Charles Lyell regarded as of incal-
culable duration,’ the work of Nature stood still, we are driven to
the conclusion that, at the advent of the first Ice-period in Upper
Pliocene times, the principal Subalpine valleys were already ex-
cavated approximately to their present depth, and that ever since
then the action of the great Alpine and Subalpine rivers has been,
as it still is in our own day, mainly directed to regaining the old
valley-floors by removing those enormous accumulations of glacial
and glacio-fluviatile material which are respectively the direct and
indirect products of three successive and general glaciations.

Discussion.

Prof. Bonney said that he had been shown some of the sections
described by Dr. Preller, and could answer for the relations of the
various gravels and moraines. He felt some doubts as to the
occurrence of ‘ Deckenschotter’ by the side of the Limmat below
Baden. He felt the greatest difficulty of all in understanding how
the Deckenschotter was deposited on the Uetliberg and yet could
occur by the Lake, for that meant a difference of at least 1200 feet,
and he saw no way of explaining this. Was the valley filled up with
loose débris, or had it been deepened? Which hypothesis offered
the less difficulty ?

The Rev. Epwry Hitt spoke of the great interest of the subject,
especially the singular alterations in the courses of rivers. Like
moraine-formed tarns, we had now shown to us moraine-diverted
rivers,

Dr. G. J. Hryvz enquired of the Author if there were any
paleontological grounds for attributing a Pliocene age to the plateau
fluvio-glacial gravels or ‘ Deckenschotter.’ The well-known fact of
the similarity of the constituents of the gravels and conglomerates,
both of those of the plateau and of the high and low terraces, must
make discrimination difficult; and he doubted the value of the
evidence relied on by the Author to prove that certain gravels and
conglomerates close to Ziirich and nearly at the level of the Lake
belonged to the same period as the ‘ Deckenschotter’ at the top of
the Uetliberg, nearly 1500 feet higher.

The Avruor thanked the various speakers for their remarks, In

1 «Antiquity of Man, 1863, p. 316. Sir Charles Lyell speaks of the
‘countless post-Miocene ages which preceded the Glacial Epoch,’ and in which
‘there was ample time for the slow erosion by water of all the principal
hydrographical basins of the Alps.’

586 GLACIAL DEPOSITS IN SUBALPINE SWITZERLAND. [ Aug. 1896,

reply to Prof. Bonney he observed (1) that, as explained in the paper,
the high-level Pliocene Nagelfluh-deposits were, in his view, formed
during the recession of the ice-sheet, and the low-level deposits
during the subsequent recession of the local glaciers left in the
valleys ; (2) that hence it was by no means necessary to assume the
Zurich Valley to have been filled with that glacio-fluviatile material
to a depth of 1200 feet—indeed, the individual deposits probably in
no case exceeded 200 feet in depth; (3) that he had found distinct
evidence of younger, loose gravel being banked against the older
calcified conglomerate both at various points near Baden and else-
where; and (4) that the Uetliberg conglomerate was not deposited
on the present narrow ridge, but on a flat Molasse dome which
afforded ample room for a glacier-stream, and whose flanks were
subsequently excavated and sapped by a parallel Postglacial river
on each side. In reply to Dr. Hinde, he said that he used the
term ‘ Pliocene ’ Nageltluh (1) because the conglomerate was clearly
younger than the Miocene conglomerate and older than the Pleisto-
cene gravels; and (2) because the first glaciation, including the
deposition of the conglomerate in question, was by Swiss geologists,
too, explicitly and on grounds of paleontological analogy, referred
to the Upper Pliocene jeriod. With regard to Mr. Hill’s remarks,
he regarded the deflection of the Sihl, from its original outlet to
the Lake of Zurich, by a stupendous moraine-wall 5 miles in length
and 400 feet in depth, as one of the most remarkable instances of its
kind in the Swiss Alps.

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CONTENTS.

Proceedings of the Geological Society, Session 1895-1896 ............:060000+ exxi-cxxviil

. PAPERS READ.
20. Mr. F. R. Cowper Reed on the Fauna of the Keisley Limestone. —Part I.

(Plates AAs GRRL) osc. s ste cradentvegeoAveae tras ites cqedpsstt ea wedges: ta ae 407

21. Dr. G. J. Hinde on new Pemmatites, Paleacis, and Eunicites. (Plates XXII.
PO NL LT aetna a Wastes ost aisien psa t ane eodigine Pris dda => Sue aves fe + aa eek Sind rn 438

22. Miss Aston and Prof. Bonney on an Alpine Nickel-bearing Sorpentin, with

MO UL SUPT OB i sotegscas voce dacs aus Dane sh ses aad ax acct ph. te ce aeaeores ote er 452

23. Prof. J. E. Talmage on Linear Marksin Sedimentary Rock. (Abstract.)...... 461
24, Mr. A. T. Metcalfe on the Capes Deposits of Nottinghamshire and Derby-

pbires,.° CADSSEACE.) Si 250 eves tls ce sda seus ve bce o ue racde sept « sey Rinna ee eer ». 461
25. Mr. J. H. Cooke on the Globigerina- limestones of the Maltese Islands.

PASUBAGL-) a ncrocs s<cedneies << caiiee s+. csanestinusieas ac Obedate 0p tat eee gaat aa 461
26. Mr, A. Strahan on a Phosphatic Chalk with Holaster planus at Lewes .......... 463
27. Mr. A. Strahan on Submerged Land-surfaces at Barry, Glamorganshire ...... 474
28. Mr. Clement Reid on the Eocene Deposits of Dorset ..............cscscecesereeees 490 -
29. Messrs. H. H. Arnold-Bemrose and R. M. Deeley on a Remains in

the Derwent. River=gravels .......06..-40-005venseee gploares-dernaecheehesaie ene 497

30. Messrs, P. Lake and S. H. Reynolds on the Lingula-Flags and Tgneous Rocks
Gieolgelly. (Plate XOXLV.) .0....20.csavesey sees ache dvennet ssee hs ooh eee 511

31. Misses Crosfield and Skeat on the Geology of the Neighbourhood of Car-
marthen. (Plates XXV. & XXVL.)

32. Prof. A. P. Pavlow on the Classification of the Strata between the Kimeridgian
and the Aptian. (Plate XXVII.)

33. Dr. C. 8. Du Riche Preller on Glacial Deposits, Preglacial ee asad Inter-
glacial Lake-Formations.in Subalpine Switzerland

[No. 208 will be published on the 2nd of next November. |]

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NOVEMBER 2nd, 1896. No. 208.

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Vol. 52. ] THE KILDARE INLIER. 587

34, The Kitparn Inurer, By S. H. Rurnotps, Esq., M.A., F.G.S.,
and C. I. Garprver, Esq., M.A., F.G.S. (Read May 27th, 1896.)

[Prats XXVIII.]

ConTENTs.
Page
ATE ee 587
Hi General Description of the Area ..............c00c00ecescees 0... 587
Ill. The Sedimentary Rocks of Grange Hill and the Chair of

AE aa ene ioe tet Sack ah ccc o ss. es. J. 589

2), Ounmurry and Grange Clare Hills ...........2.......0-......... 595
V. Summary of Conclusions as regards the Sedimentary Rocks. 595
VI. The Igneous Rocks of Grange Hill ...............000..0-000..... 596
NEN US ie ce coe oo aic Chic on cde Sadhvi c= écoveececiscoaoses, 600
VIII. Summary of Conclusions as regards the Igneous Rocks 603
IX. General Conclusion and Summary .................cceecceseess. 604

I. Intropuction.

Tar Geological Survey of Ireland, in 1858, published a memoir
describing the geology of the Kildare Hills and neighbouring
country. In this memoir are given lists of fossils from the lime-
stone and from an underlying ash-bed, attention is drawn to the
resemblance which some of the igneous rocks bear to those of
Lambay Island, and reference is made to the presence of a north-
and-south fault dividing the inlier into two portions.

In 1877 Messrs. Harkness and Nicholson,' in their paper on
‘the Strata between the Borrowdale Series and Coniston Flags,’ give
Some account of the Kildare rocks. They mention that the lime-
stone is in the direct line of strike of contemporaneous beds at
Portraine, near Dublin, and also of the Coniston Limestone of the
Lake District. Moreover they judge from the strike of the Kildare
limestone that it is faulted against the rocks east of it, and note
that the beds west of the north-and-south fault above mentioned
are entirely dissimilar to those lying east of it.

The area has been repeatedly referred to by Mr. J. E. Marr? in
his various papers on the Coniston Limestone Series of the Lake
District. In them he draws special attention to the resemblance
between the Keisley Limestone and that of the Chair of Kildare.

II. Generat Description or THE AREA.

The Carboniferous Limestone to the south-west of Dublin has
been thrown into a series of gentle undulations, and to the north
and north-west of the town of Kildare the crest of one of these
undulations has been denuded away, exposing a strip of pre-
Carboniferous rocks. The inlier thus formed is some 6 miles long,

&, * Quart. Journ. Geol. Soc. vol. xxxiii. (1877) p. 481.
* Geol. Mag. 1892, pp. 97 et seqg.

Q.J.G.8. No. 208. 2s

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Vol. 52.]

and on the average about ?# mile broad.

THE KILDARE INLIER. 589

In this small area there

are exposed rocks of Ordovician and probably also of Silurian age,
while red micaceous sandstones and quartzose conglomerates, referred
by the officers of the Geological Survey to the Old Red Sandstone
Series, protrude in places from beneath the Carboniferous Limestone,
and rest on the upturned edges of the older rocks.

The area is easily noted from a distance, as it is formed of four
prominent hills arranged in a line running roughly in a north-east
and south-west direction, and rising some 400 to 450 feet above the
level of the surrounding country. Of these four hills, that farthest to
the south-west is Grange Clare Hill, then comes Dunmurry Hill, then
Grange Hill with the Chair of Kildare as a projection, while finally

to the north-east lies the Hill of Allen.

The whole of the sur-

rounding country is deeply covered with drift, the junction of the
Carboniferous Limestone and Old Red Sandstone with the beds of

the inlier being never seen.

We shall describe first the sedimentary and afterwards the
igneous rocks ; and since the stratigraphical succession is best seen
on Grange Hill we shall first describe that hill, including with it the

Chair.

The complete absence of cliff or stream-sections has rendered the
correlation of the beds a matter of some difficulty.

Ill. Tue Sepimentary Rocks or Grange HILL AND THE
CHAIR oF KILDARE.

The lowest beds are seen on the northern slopes of Grange Hill.
They consist of olive-green gritty shales dipping south-east at an

angle of from 60° to 70°.

Associated with them are some more

definitely gritty bands which pass occasionally into a conglomerate
containing well-rounded pebbles of shale and grit, often some ? inch
in length. These gritty shales pass up into an andesitic ash which
can be traced all along the foot of -the hill to a point north-north-

west of the top of the Chair.

This ash has proved very fossiliferous

just behind Grange Hill House Cottage, where it is exposed some
10 feet below the base of the overlying igneous rock, under which

it dips to the south-east at an angle of about 60°.

At this point,

moreover, it is of a distinctly more gritty type than elsewhere.
From.-this ash we obtained the following fossils :—

Pinacopora Graye, Nich. & Eth.

Orthis porcata, M‘Coy

alternata, Sow.

flabellulum, Sow. (very common)

calligramma, Sow.

testudinaria, Sow.

Strophomena deltoidea, Conrad

expansa, Sow. (common)

Leptena (Plectambonites) sericea, Sow.

Calymene senaria, Conrad (very
common) '

Calymene Blumenbachii, Brongn.

Ctenodonta varicosa, Sow. (very
common)

Orthonota parallela, Hall

Modiolopsis expansa, Portl.

Raphistoma equalis, Salt. (very
common)

Holopella, sp.

Murchisonia sulcata, M‘Coy

Pleurotomaria cf. claustrata, Lindstr.

282

on

590 MESSRS, 8. H. REYNOLDS AND C. I. GARDINER [| Nov. 1896

Fig. 2.—Map of the Central portion of the Kildare Inher

»
Wety 1 ta 4" re
Et eee
Wyn ys Loy
ner:

Section 2.

Section 7.

a (Hills,
Grits of Grangeclare & Dunmurry

— gyal eee ; [above te Lava. =
ee =o & Shales of ae Hil lying Es Tuff or Ash.
TMA rea Shales of Dunmurry. Sa Middle Bala Limestones of the Chair. Lava of Grange Hill,
: TIT » (Grange Hill. wry. : :
i Black Shales of Dunmurry. A Grits §& Slates lying below the Ash of en Porphyritic basalt of Graige Hul
1 mile. ]

Pin ge

USilurian |

[Scale : 3 inches =

Note.—The numbers when unaccompanied by dip-arrows indicate spots referred to in
the text or from which specimens thus numbered, and now in the Woodwardian
Museum, Cambridge, were obtained

Drift covers the westerly extension of the igneous rocks from Grange Hill

For ‘ Dunmurry’ in the explanation, read ‘ Dunmurry Hill.’

The top of the hill is formed of igneous rocks, basic and inter-
mediate in character, and these, as shown in fig. 3, are overlain by

olive-green grits and gritty shales yielding no fossils except an
No alteration can be detected either in the grits

obscure Orthis.

Fig. 3.—Section 2 on Map.

Grange Hill
House. Hill.

SRAleaaa Carboniferous

pie es ane
ee Grits Limest.overlain

Cogan Shales an Dd i PE Te Ants

LAn2eSt.0verlain rts We

by Drift Ash Basalts Basalt by Drift
6 inches = 1 mile. Vertical scale exaggerated. |

[Horizontal scale :

Vol. 52. | ON THE KILDARE INLIER. 591

and slates above the igneous rocks or in the ashes below them.
The igneous rocks are therefore almost certainly contemporaneous,
and this view is confirmed by an examination of their structure
both in the field and under the microscope. We shall describe
these rocks in a later part of this paper.

At the western end of Grange Hill is the Chair of Kildare, where
the rocks are markedly different from those forming the main mass of
Grange Hill. The lowest bed seen is an ash-band continuous with
that which lies immediately below the lavas of Grange Hill. This
ash is exposed in the lane leading north-east to Grange Hill House,
and between this lane and the Chair no more rocks are seen in situ.
This tract of country is, however, in the direct line of strike of the
lavas of Grange Hill; and it seemed

at first as if we had evidence of their Sho
extension to this point, from the Seis tS
occurrence of a small quarry exposing Pen =
numerous blocks of lava which were SE et
apparently taken to be in situ by the _, * 932 =
officers of the Geological Survey. After Ho "$274 mo
some consideration, however, we came = ‘¢--- zs
to the conclusion that these blocks were # M] "3
not in place, and that although the =
lavas probably do extend to this point § bee
we have no proof of their doing so. e Sesh

The limestone of the Chair appa- a “? a2
rently forms one main mass andseveral = iS at a
smaller lenticular masses, separated one 5 & Fo |
from another by tracts of country which |) $5 “ “>
generally show no exposures and are =~ %- S
probably occupied by shales. Sections =, b&_ S
show that the microscopic characters ° & a“
of the limestone do not vary muchin 4 § °
different parts, for everywhere therock 2 4 ag
is partly horny, partly crystalline, $ §. =
being formed of well-cleaved plates of 2 § =
calcite. We divide the limestone into 2 3
four bands, A, B,C, and D, ofthe same ¢ oS
general age. ® FS

r 3 = ag S

The succession of the limestone- @ 343 BO
bands is shown on p. 592, but the § SF TRA
thicknesses given for the various beds = & ..
are only approximate, it being scarcely ae
possible to measure them accurately 33S
owing to the difficulty in ascertaining S38
the dip. The limestone, however, =

as

has the normal north-east and south-
westerly strike of all the beds of Grange Hill, and it dips south-
east at a rather high angle. The lowest beds are seen at the foot
of the Chair, Taking 50° as the average dip, we have the following
section at the top :—

592 MESSRS. 8. H. REYNOLDS AND ©. I. GARDINER [ Nov. 1896,

Feet.

Calcareous flags and shales of the Chair farmyard ............ 15 seen.
Gap) Gimseen) ine sseresrtcicnonoetences about 40
D. Variable limestone with shaly partings ...............cceeeeees 40
Gap \(Umscem) Mae .co ce-ch. sara teeres about 30

Exposures of red or grey limestone, sometimes horny, some-
times crystalline, with many fossils, are scattered over the

—C next strip of country, about 250 yards wide. We have no
evidence against this all being one mass of limestone,

though beds of shale may occur in it............ about 550
Gap Umseen)) seeka nics ed steele ece san eeieeeetee 20
Red and grey limestone, chiefly horny .................:2c0cesees 20
gp, J Green sandy shales and grits of the Marl’s Well ... about 20
’ | Shaly limestone with basal breccia of shaly fragments in a
CAlCane OUS MMA UI: caeee csc se re «ep sien. 200 ust anes wee ele nee 14
{ Red, occasionally grey, horny lirsestone, becoming crystalline
Fill LAC ES ren PAE © «ction Wal sheta ciel of. _slanaccm sete cnem he eee Reeeee 16 seen.
Dota .35.055. senor eee 765 feet.

The red limestone (A) at the base of the Chair is partly crystalline,
partly horny. The two kinds of limestone do not occur in definite
layers; sometimes they appear to shade off into each other, but
generally they end abruptly. The crystalline limestone is chiefly
composed of broken crinoid-stems and fragments of trilobites,
especially I7lenus. The horny limestone has yielded few fossils ; it
is occasionally greenish, though usually red, and passes up into a
shaly limestone with a basal breccia consisting of shaly fragments
embedded in an abundant calcareous matrix. These shaly fragments
are sometimes so well rounded that the rock might be called a con-
glomerate. In places the fragments of shale are seen standing out
freely on the weathered surface, with their longer axes all arranged
parallel to one another. This band (A) is on the line of strike of
some greenish grit exposed farther east.

The limestone (A) has yielded the following fossils :—

Cyathophyllum, sp.? Cheinoma (Pseudospherexochus) cf.
Crinoid. conformis, Ang.

Agnostus trinodus, Salt. Spherexochus latirugatus, Reed, MS.
Acidaspis, sp. Tiresias insculptus, M‘Coy

AMpYyL, Sp. Trinucleus (?) concentricus, Haton
Cheirurus bimueronatus, Murch. Remopleurides longicostatus, Portl.
Ilienus Bowmamni, Salt. Cyphoniscus socials, Salt.

Discina ef. gibba, Lindstr.

The next overlying beds are the green sandy shales and grits of
the Earl’s Well. These yielded no fossils.

Next comes the red horny limestone (B), which forms much of the
upper part of the Chair, and can be traced away from it both north-
east and south-westward. In it we have found :—Agnostus tri-
nodus, Salt., Cyphoniscus socialis, Salt., Cheirurus, sp., Lllenus
Bowman, Salt., and Remopleurides longicostatus, Portl.

The extreme top of the Chair is formed of rock that is not in
place. When followed farther north-eastward to a point due north
of the Chair Farm, the limestone-band (B) becomes very earthy,
and contains the following fossils:—<Atrypa marginals, Dalm.,

a

Vol. 52.] ON THE KILDARE INLIER. 593

Orthis testudinaria, Dalm., Orthis vespertilio, Sow., and Strophomena
(Leptena) rhomboidalis, Wilck.

We group all the exposures of limestone on the slope of the hill
south and east of the Chair in one broad band (C). This limestone
is sometimes red and horny, but is generally grey and more or less
crystalline. Fossils ‘are more plentiful in it than in any of the
other bands—Primitia M‘Coyi, Lllenus Bowmani, and Sphereawo-
chus mirus being specially abundant. It yielded :—

Cyathophyllum, sp. Atrypa apiculata, Salt. & Forbes
Heterocrinus (7). expansa, Lindstr.

Primitia M‘Coyi, Salt. — marginalis, Dalm.

Acidaspis cf. evoluta, Tornq. Hyatella (Athyris) Portlockiana,
Cheirurus cf. clavifrons, Dalm. Day.

Homalonotus punctillosus, Tornq. Leptena quinguecostata, M‘Coy
LIlienus Bowmani, Salt. Orthis alternata, Sow.

calligramma, Sow.
(?) vespertilio, Sow.

cecus, Holm
fallax, Holm

— *Linnarssoni, Holm (?=1J. Strophomena (Leptena) rhomboidalis,

Bowmani, var.) Wilck.
Lichas hibernicus, Portl. corrugatella, Dav.
—— levis, Hichw. —— expansa, Sow.
wae— laxatus, M‘Coy —— imbrex, var., Pand.
— margaritifer, Nie ef. luna, Torng.
Phacops, sp. Triplesia (Orthis) insularis, Kichw.
Proetus cf. ramisulcatus, Nieszk. Streptis (Triplesia) monilifera,
Remopleurides longicostatus, Portl. M‘Coy
Spherexochus latirugatus, Reed MS. Ambonychia, sp.

mirus, Beyrich Inoceramus trigonus, Miinst.

Staurocephalus Murchisoni, Barr. Holopea concinna, M‘Coy
Ptilodictya acuta, Hall Trochus rupestris, Kichw.
—— lanceolata, Goldf. Orthoceras suave, Ang.
Fenestella assimilis, Lonsd. —— velatum, Blake

The highest band of limestone (D) is exposed in the field imme-
diately north-west of the Chair Farm, and here a considerable
thickness is seen. The lower beds at this locality consist of grey
limestone which becomes earthy in places and sometimes has shaly
partings. The upper beds are chiefly reddish and horny, and contain
few fossils, the commonest being Fuvosites fibrosa.

From the band (D) we obtained the following forms :—

Favosites fibrosa, Goldf. Lingula ovata, M‘Coy

Cyathophylium. Atrypa marginalis, Dalm.

Stromatoporoids. Orthis alternata, Sow.

Acidaspis bispinosus, M‘Coy —— biforata, Schloth.

Cheirurus (Pseudospherexochus) cf. —— spiriferoides, M‘Coy
conformis, Ang. Strophomena expansa, Sow.

Illenus Bowmani, Salt. —— (Leptena) rhomboidalis, Wilck.

Lichas hibernicus, Portl. Christiania (Leptena) tenuicincta,

Lichas, sp. bois M‘Co

Phacops, sp. Streptis (Triplesia) monilifera,

Remopleurides longicostatus, Portl. M‘Coy

Harpes Wegelini, Ang. Triplesia (Orthis) insularis, Eichw.

Ptilodictya lanceolata, Hall Holopea concinna, M‘Coy

Fenestella assimilis, Hall

Note.—For the determination of very many of our specimens we
are indebted to Mr. F. R. Cowper Reed, M.A., F.G.S., to whom we
wish to express our most hearty thanks.

594 MESSRS, 8. H. REYNOLDS AND C. I. GARDINER [ Noy. 1896,

The uppermost limestone is succeeded by calcareous flags and shales,
which are exposed in the Chair farmyard. From these we
obtained :—Agnostus trinodus, Salt., Agnostus, sp., Cyphoniscus soci-
alis, Salt., Asaphus, sp., Trinucleus, sp., and Spherexochus mirus,
Beyrich.

No other exposures occur till, at about + mile due east of the
Chair Farm, there is a small quarry showing hard micaceous grits
with shales above them dipping east at 24°. After this no more
exposures are seen.

As we said before, owing to the compactness of the Chair lime-
stone and the absence of divisional planes, it is extremely difficult
to obtain any clear idea as to its dip and thickness. It is evidently
a lenticular mass, but appears to have been deposited in much the
same state as we now find it, and not to have assumed its lenticular
shape as a consequence of the folding and squeezing out of the
shales in the way suggested by Messrs. Nicholson and Marr * con-
cerning the Keisley Limestone. We never saw in it any signs of
crushing and folding, nor of the enclosure of wisps of shale, neither
are any of the fossils distorted. Nor did we see any evidence of its
being faulted against the rocks to the east in the manner suggested
by Messrs. Harkness and Nicholson.

The Chair limestone, as remarked by Messrs. Harkness and
Nicholson, is identical in many respects with the Keisley Limestone.
The two agree lithologically in varying as regards colour from red
1o grey, and as regards texture from horny to crystalline. They
agree also most closely as regards their fauna.

Although the Chair limestone can be divided into four fairly
well-marked bands, yet various forms range through it from top to
bottom, and it is probably all on much the same horizon. The four
most characteristic forms which range through it are :—Agnostus
trinodus, Salt., llanus Bowman, Salt., Remopleurides longicostatus,
Portl., and Cyphoniscus socialis, Salt.

Though we obtained Staurocephalus at a lower horizon, we care-
fully searched the upper beds without finding any forms character-
istic of the Stawrocephalus-limestone which occurs immediately
above the Keisley Limestone in the Lake District. As, however,
nearly all the Proterozoic rocks south-east of the exposure of shaly
beds in the Chair farmyard are covered with drift, the Stawro-
cephalus-limestone may very possibly occur here, though it is not
now exposed. ,

* Quart. Journ. Geol. Soc. vol. xlvii. (1891) p. 508, and Marr, Geol. Mag.
1892, p. 101.

Vol. 52. | ON THE KILDARE INLIER, 595

IY. Dunmurry ano Grange Crare Hits.

These two hills occur to the south-west of the Chair and Grange
Hill, and are cut off from them by a fault which runs along the
valley traversed by the Kildare and Rathangan road. The rocks
which form these two hills are, as a whole, strikingly different from
those forming the hills to the eastward.

The lowest beds found in this part of the inlier crop out along
the northern and north-eastern face of Dunmurry Hill. They con-
sist of somewhat black shales, highly ochreous in places, which pass
up into more olive-green shales, and are succeeded by a band of red
earthy shales. These red beds are very easily marked, and some-
times where they are not seen in situ their presence may be inferred
from the colour of the soil. They are also seen in the road 3 mile
north of Dunmurry House. We searched all these beds carefully for
fossils, but without success. In the Dublin Museum, however, are
specimens of Jllanus Bowmani, Salt., and Leptena quinquecostata,
M‘Coy, which obviously come from the red beds.

The red shales become more sandy above, and are succeeded by
compact grey and greenish micaceous grits which form the main
mass of Dunmurry Hill. These beds all have a general S.E.-and-
N.W. strike, while that of all the beds east of the fault is N.E.-and-
S.W. They dip south-west at an angle of 25° to 35°.

At the extreme northern foot of Dunmurry Hill, by the hedge,
there occurs at one point an exposure of Chair limestone, and east
of it a patch of greatly altered lava with porphyritic felspars. We
came to the conclusion that these were not in place.

Grange Clare Hill is formed entirely of green and grey micaceous
grits with occasional shaly bands. ‘These beds are thrown into a
series of folds, as shown by the dip-angles.

V. SuMMARY oF CoNCLUSIONS AS REGARDS THE SEDIMENTARY Rocks.

We found no paleontological evidence to determine the age of the
beds forming Dunmurry and Grange Clare Hills, and the two fossils
in the Dublin Museum are insufficient for the purpose, as, although
they occur in the neighbouring Chair limestone, they also range up
into beds of Valentian age. It seems to us improbable that beds
so absolutely different lithologically should be deposited contempora-
neously in areas so near together as the Chair and Dunmurry Hills,
and we are therefore disposed to think that the Dunmurry beds are
of Silurian age. The grit of Dunmurry resembles the grit previously
mentioned as exposed in a small quarry 7 mile east of the Chair
Farm, and it is possible that the red and black shales of Dunmurry,
as well as the Staurocephalus-limestone, may be present in the drift-
covered tract of land between the Chair Farm and the grit quarry.

We would, therefore, group the sedimentary rocks of the inlier as
follows :—

659 MESSRS, 8S. H. REYNOLDS AND C. I. GARDINER [ Nov. 1896,

DunmurRyY AND GRANGE CuHaArr or KILDARE AND
CuARE HILLs. GRANGE HI.
Grey and green micaceous Green micaceous grits
?=Coniston Grits ritsand shales formin seen + mile east of Chair
§ ‘ 8 4
AND FLAGs. the main mass of the Farm.
hills.
Red shales.
?1=STocKDALE SHALEs. | Binceenaes No exposure.

No exposure ? horizon of Stawrocephalus-limestone.

Flaggy shales with T7ri-
nucleus in Chair farm-
yard.

Band D—variable lime-
stone with Savosites
jibrosa,

Band C—crystalline and
horny limestone with
many fossils, including
Lichas.

Band B—red horny lime-
stone with few fossils.
Green sandy shale and

grit of the Harl’s Well.

Shaly limestone and brec-
cia of shaly fragments.

Band A—red and grey
horny and crystalline
limestone of the foot of
the Chair.

SERIES.

No exposures.

Contemporaneous igneous
rocks of Grange Hill.

Fossiliferousash of Grange
Hill House Cottage.

(
|
Coniston LIMESTONE 4
|
\ Green gritty shales.

VI. Tue Ienrous Rocks or GRANGE HILL.

The igneous rocks of Grange Hill form the summit of its whole
ridge, and extend for nearly a mile in a north-east-and-south-westerly
direction. An ash-bed, generally light green in colour, but weather-
ing brown, is exposed frequently along the north-western slope of the
hill, and behind Grange Hill House Cottage has yielded abundant
organic remains. The beds immediately beneath and above this ash-
bed are exposed at a very few places. Close to Grange Hill House
there occurs immediately beneath the ash-bed a very vesicular light
green andesite, the vesicles being filled mainly with a dark green
mineral. A section of the rock shows a groundmass almost entirely

1 Messrs. Harkness and Nicholson say that the shales of Dunmurry are
exceedingly like the Graptolitic Mudstunes=Stockdale Shales of the Lake
District.

Vol. 52.] ON THE KILDARE INLIER. 597

formed of small crystals of oligoclase exhibiting excellent flow-struc-
ture, and embedded amongst them occur large porphyritic felspars,
now entirely replaced by calcite and chlorite. The vesicles are filled
with a chloritic mineral and quartz, the quartz often showing a
partially spherulitic structure. Such an andesite occurs also in a
similar position with regard to the ash-bed at the north-easternmost
exposure on the hillside. Sections of the ash itself (see Pl. XX VIII.
fig. 4) show more or less rounded fragments of lava in which small
felspar-needles are easily recognizable, and these fragments, together
with numerous broken telspars, are embedded in a matrix of calcite
and of isotropic brown material. Quartz-grains and patches of a
green chloritic mineral are also present. The most interesting
exposure of this rock is close to Grange Hill House Cottage, where
it becomes more gritty, the quartz-grains increasing in number
while the fragments of lava and shattered felspar-crystals are not
nearly so evident ; and here, as mentioned above, it becomes very
fossiliferous.

Above the ash-bed there is seen in places another band of ande-
site, also light green in colour, and sometimes very vesicular (see
Pl. XXVIII. fig. 5). A section shows a fresh and abundant
groundmass composed of acicular plagioclase-felspars exhibiting
flow-structure, granular augite largely replaced by calcite, and
much magnetite. One slide also shows some bastite-pseudomorphs
atter a rhombic pyroxene. The porphyritic constituents are large
felspars, often completely replaced by calcite, while the vesicles are
filled with an outer ring of quartz and an inner mass of a chloritic
mineral, which is often of a slaty-blue colour in polarized light.

This andesitic flow is covered by a basalt, sometimes dark and
compact, sometimes very vesicular. Exposures of this basalt are
fairly frequent along the hillside, the rock being recognized by its
very fresh black porphyritic augites, sometimes 7 inch long; occa-
sionally, however, green platy felspars are the more obvious
porphyritic constituents. One of these rocks was found to have a
specific gravity of 2°93, and a silica-percentage of 48°15. Some
specimens show a red mineral with a good cleavage, occurring as
small spots throughout the rock. Under the microscope the ground-
mass of this rock is seen to consist chiefly of lath-shaped felspars
and grains of augite with a certain amount of interstitial matter.
The porphyritic augites are, as a rule, well preserved; they some-
times show a zonal structure, and often occur in groups of irregular
crystals; in one instance excellent ‘ hourglass structure’ was clearly
seen. The porphyritic felspars are seldom very fresh, though there
is often a kernel of much altered material surrounded by a marginal
deposit of fresh secondary felspar.

The red mineral which has been mentioned above as being visible
as spots in a hand-specimen appears to be an iron oxide, generally
replacing augite (see Pl. XXVIII. fig. 1). In some cases it occurs
as a more or less circular core within a mass of secondary material
which fills up completely the space originally occupied by the augite.
Sometimes, however, the iron ore is associated directly with augite,

598 MESSRS, S. H, REYNOLDS AND Cc. I. GARDINER [ Nov. 1896,

without any other secondary material having been developed. The
iron ore is dichroic, being red-brown and purple-brown in colour; in
polarized light it assumes a rather brighter red-brown colour, the
greatest amount of absorption taking place when the cleavage-lines
are parallel to the short axis of the polarizer. Cracks sometimes
run through the outer coat of secondary material which are filled
with an iron ore distinctly redder than the above-mentioned one,
and this is probably hematite. The edge of the core, where it
comes in contact with the outer ring of secondary material, is very
ragged and uneven. In some cases the purplish iron ore occurs not
only as the core of the replaced augite, but also in the cracks and as
a rim fringing the whole crystal-outline, while in other cases it has
come inirregularly. Ina few instances the iron ore occurs in relation
to little patches of serpentine, which probably represent original
crystals of olivine.

Another mineral sometimes present, though found more frequently
in the rocks of the Hill of Allen, occurs in the form of small brown
or yellow rounded grains with a radiating structure. They can
often be completely rotated under crossed nicols without extin-
guishing. They are found most commonly enclosed in amygdules
of chlorite, and are probably chalybite.

Some of these basalts possess large platy felspars and serve as a
link to a peculiarly coarse basalt which is found at the western end of
the hill. ‘This is a very striking rock; its junction with the basalts
beneath is uneven, and portions of the underlying rock appear to
have been enclosed in its base. A hand-specimen shows a grey
compact groundmass, in which are numerous greenish felspars often
almost circular in section, sometimes 4 inch in diameter, and ;4 inch
thick. There is a general tendency for these felspars to be arranged
with their flat faces parallel to each other.

A section of this rock shows a groundmass of lath-shaped felspars,
augite, and magnetite. The augite is very much more plentiful in
this groundmass than in that of any other rock from the hill; it is
allotriomorphic, fillmg up the spaces between the felspar-needles,
which are not often twinned and give small extinction-angles, being
apparently allied to oligoclase. Some serpentine and small crystals
of a yellowish pseudomorph after rhombic pyroxene are also
present. The porphyritic constituents are, firstly, large plagioclase-
felspars allied to labradorite and often much altered, and secondly,
groups of augite-crystals, the individuals of which are frequently
well zoned. Amygdules are fairly plentiful; their outermost rim is
generally formed of partially spherulitic quartz, within which is a
mass of green chloritic mineral, often enclosing numerous small
circular spaces filled with clear transparent quartz, which 1s some-
times beautifully spherulitic.

Though this rock has been found only towards the western part
of the hill, and its base 1s irregular and sometimes encloses portions
of the underlying rock, there seems no necessity to consider it
intrusive. The adjacent rocks show no sign of alteration, and there

Vol. 52.] ON THE KILDARE INLIER, 599

are several rocks among the more basic flows which approach it in
character.

Not far south of this exposure of coarse rock—south and south-
west of the actual summit of the hill—occurs a patch of an andesite-
rock having a compact blue or black groundmass in which small
felspars can be detected on examination of a hand-specimen. Sections
of this rock resemble those of the lower andesitic flows. A ground-
mass of small lath-shaped felspars, very small augite-grains and
magnetite, is tobe seen. The small felspars are allied to oligoclase,
and the groundmass shows here and there a perfectly spherulitic
structure. Fair-sized porphyritic felspars occur, much altered, but
probably labradorite. Epidote occurs occasionally, and a few
amygdules are to be seen with an outer rim of epidote and quartz,
the latter often showing good spherulitic structure in polarized light.
Analyses of this rock gave 55-02 per cent. of silica, and the specific
gravity of the rock was found to be 2°82.

The story told by the igneous and other rocks of Grange Hill
appears therefore to be this:—After the deposition of the unfossili-
ferous muds and sandy shales now found along the base of the
north-western slopes of the hill, the period of igneous activity
was heralded by a slowly creeping flow of andesite; this made its
way along the sea-floor without producing any apparent chemical
alteration in the beds over which it crept. Soon, however, the ashes
which no doubt accompanied the outburst of lava settled down as
a thin deposit on its surface, enclosing here and there the animal
remains which are now found fossilized and give us proof that
all this occurred in Middle Bala times. The deposit of ashes was
then covered by another andesitic flow, and then the nature of the
lavas which crept over this portion of the sea-floor altered. They
became more decidedly basic and basaltic in character, the alteration
in chemical composition being accompanied by a darkening in
colour, and the more obvious and frequent occurrence of augites.
These rocks, too, are very vesicular in places, though the flow-
structure is not visible under the microscope as it is in the earlier
andesitic flows. The large felspars that floated along are, however,
all arranged with their long axes pointing more or less in one
direction, and testify to the fact that these rocks, too, crept along
the sea-floor and are true lavas. The upper surface of these flows
—no doubt very rugged and uneven—was then covered by a very
much coarser basalt, and as the latter crept along it appears to
have broken off pieces of the underlying flows and incorporated
them with itself. This flow also was vesicular, and appears to be
covered at one locality by a second flow of andesite. After this
igneous action ceased, and the deposition of mud and sands once
more occurred. But in places to which mud and sand were not
brought limestones were laid down, and finally the whole was
covered by the sandy beds which now form the grits that occur
south-east of the Chair.

600 MESSRS, 8, H. REYNOLDS AND C. I. GARDINER [ Nov. 1896,

VII. Tue Hitt oF Auten.

At the present time no sedimentary rocks are exposed on the
Hill of Allen, and the succession of the igneous rocks is by no means
easy to make out. ‘There are several well-marked bands of rock
which strike roughly north-east and south-west, but the direction
of their dip is not very clear.

The ashes and andesites seen at the base of the igneous rocks of
Grange Hill have no representatives exposed on the Hill of Allen,
where the lowest rock seen is that at the base of the south-eastern
face, and is a dark vesicular basalt, generally characterized by the
presence of porphyritic augites. Under the microscope, porphyritic
felspars are to be seen as well; these are, however, nearly always
greatly altered, though the alteration-products are commonly rimmed
with fresh secondary felspar. In arock from the spot marked 60
on the map (fig. 1, p. 588) many of the felspars are very fresh and
well twinned.

Resting on this comes another basalt, fine in texture, showing no
porphyritic constituents in a hand-specimen, and generally some-
what red in colour, though occasionally green. This rock is often
very vesicular, the vesicles being filled either with calcite or chlorite.
Some sections show a groundmass deeply stained with hematite
and containing many small felspars. The porphyritic constituents
include fair-sized plagioclase-felspars with their margins much
fretted and their substance entirely replaced by alteration-products.
Large fresh augites occur aggregated together, and there is present,
as on Grange Hill, a mineral in the form of shapeless grains often
crossed with curved cracks. These grains are generally surrounded
by a deep red-brown rim of hematite which also fills the cracks,
while the spaces between the cracks are now often occupied by
serpentine. There seems every probability that these were originally
grains of olivine. Grains of chalybite are often found quite similar
to those in the rocks of Grange Hill.

These basalts are, we think, to be correlated with those which
immediately overlie the lowest andesitic flows of Grange Hill.
Amongst both we find rocks sometimes dark green, sometimes red,
showing sometimes porphyritic augites, sometimes porphyritic
felspars. Sections of these rocks from both hills show augite-
crystals aggregated together, and porphyritic felspars which have
been entirely replaced by alteration-products and afterwards rimmed
with fresh felspathic material. The occurrence of chalybite, and of
pseudomorphs after olivine, is also characteristic of both hills.

On the Hill of Allen, as on Grange Hill, these basalts are over-
lain by a coarse porphyritic basalt, the junction between the two
being in some places very sharp and in others more or less irregular.
At some points there seem to be portions of the fine basalt caught
up in the coarser rock, and this is particularly noticeable at a point
east of the tower on the top of the hill, where a well-marked but
very local breccia occurs. This breccia consists of blocks of both
the coarse and fine rocks mingled together. The blocks and frag-

Vol. 52. | ON THE KILDARE INLIER. 601

ments include both rounded and angular individuals, and are of all
lengths up to about a foot. This irregular base to the coarse rock
was also noticeable to some extent on Grange Hill.

The coarse rock occurs along two parallel lines on the south-eastern
face of the hill, the lower line ending off abruptly about 30 feet
below the point where the upper line as abruptly begins. There
seems to be a small fault here causing this discontinuity. Exposures
of the coarse rock also occur at various points on the western face
of the hill, and one small exposure was found low down the hill-
side, due east of the Carrick tower.

The appearance of this rock in the field is exactly like that of the
coarse basalt from Grange Hill. There is the same grey, somewhat
crystalline groundmass enclosing the same large white or greenish-
white porphyritic felspars, which are often almost circular in outline
and of no great thickness, while most of them lie with their flat faces
parallel to each other. Vesicles filled with calcite and a chloritic
mineral are similarly to be observed in the rocks from both hills.

Under the microscope the resemblance between the coarse rocks
of the two hills holds equally well (see Pl. XXVIII. fig. 2). In
each we see the same prominent groundmass formed of small
idiomorphic crystals of plagioclase and allotriomorphic granules
of augite in almost equal proportions, the same development of
magnetite, green serpentine, and yellowish pseudomorphs after a
rhombic pyroxene, while the porphyritic constituents in the two
cases are seen to be fresh augites and large felspars allied to
labradorite.

Most of the upper part of the hill is formed of an andesitic rock
(67, 78], which overlies the coarse basalt and has a very definite
character. It is rather light green in colour and marked with
numerous red spots which are patches of hematite. A hand-
specimen shows no obvious porphyritic felspars, but many fresh
black augites are to be seen. |
- Under the microscope (see Pl. XXVIII. fig. 6) it is seen to be
characterized by having a groundmass crowded with small rect-
angular or nearly square sections of a fairly fresh felspar allied to
oligoclase ; but it contains also augite, bastite-pseudomorphs after
a rhombic pyroxene, and magnetite. Porphyritic felspars occur,
‘much altered and epidotized, but possessing an outer rim of fresh
secondary felspar. Porphyritic augite and altered rhombic pyroxene
are to be seen, the two minerals being sometimes intergrown in a
complicated manner (see Pl. XXVIII. fig. 3). It is the occurrence
of abundant small felspars which appear square or rectangular in
sectiou that marks off this hypersthene- or enstatite-augite-andesite
from the other rocks of the hill. An analysis of this rock showed
58°5 per cent. of silica, while the specific gravity was 2°81.

The rest of the north-western slope of the hill is formed of rocks
dark in colour, which show very obvious porphyritic felspars in a
hand-specimen. They almost invariably show bastite-pseudomorphs
after rhombic pyroxene, augite, and magnetite in their groundmass,
together with felspars having low extinction-angles, while the

602 MESSRS. S. H. REYNOLDS AND C. 1, GARDINER [ Nov. 1896,

porphyritic constituents are fair-sized plagioclase-felspars and
augites. The felspars are very greatly altered, but are generally
rimmed with a layer of fresh material; the augites occur in masses
of aggregated crystals, often accompanied by rhombic pyroxene.

In two rocks from different ends of the hill porphyritie horn-
blendes, showing the characteristic cleavage and pleochroism, are
to be seen. Thecrystals are much fretted away, and replaced round
their margins by fringes in which one can recognize magnetite and
hematite. These marginal fringes occur round all the hornblendes,
while here and there patches of similar constitution occur without
any central hornblende, though no doubt the patches have been
formed from hornblendes in the same way as the fringes. One of
these rocks, from the spot marked 80 in the map, has 52°8 per cent.
of silica, and its specific gravity is 2°8. This rock is also noticeable
for the presence of amygdules of chlorite enclosing beautiful little
spherulites of quartz similar to those of Grange Hill (see fig. 5).

Fig. 5.—Hornblende-andesite (80), Hill of Allen. x about 40.

The section was drawn in polarized light, and shows a large patch of a
chloritic mineral enclosing numerous little spherulites, probably of quartz,
all with the characteristic black cross.

At the northern end of the hill occurs a fine dark-coloured, some-
times vesicular, compact basalt, more or less in the line of strike
of the last-mentioned rocks. Sections of this rock are remarkable
for the large amount of magnetite in the groundmass, and its aggre-
gation round some of the vesicles and felspars in a way sometimes
recalling the appearance of micropegmatite. The felspars are much
altered, and give a low extinction-angle. The augites form large
plates, and are sometimes very fresh, sometimes much altered.

Vol. 52.] ON THE KILDARE INLIER, 603

It will thus be seen that the rocks of Grange and Allen Hills are
very closely allied. On both hills we meet with :—(1) rocks which
have large aggregated masses of augite-crystals; (2) rocks with
what are probably pseudomorphs after olivine ; (3) rocks with large
labradorites; (4) rocks with the groundmass largely formed of
small felspars with square or rectangular cross-sections ; (5) rocks
with bastite-pseudomorphs after a rhombic pyroxene; (6) rocks with
altered felspars, whose margins are made up of fresh secondary
felspar ; (7) rocks with plentiful spots of chalybite; (8) rocks with
large vesicles filled with a chloritic mineral or serpentine in the
centre, and round the margin with quartz, which is often partially
spherulitic and sometimes encloses very perfect little spherulites.

There is thus plenty of evidence that the igneous rocks of the Hill
of Allen are very similar to those of Grange Hill; and although no
sedimentary rocks are exposed now on the Hill of Allen, we consider
it quite certain that these igneous rocks are of Bala age, and that
they are all of the nature of lava-flows.

The greater area covered by these rocks on the Hill of Allen, as
compared with Grange Hill, may best be accounted for by an
alteration in their dip due to a fault between the two hills, running
in a direction more or less parallel to the fault at the base of the
Chair of Kildare. The beds of the Hill of Allen differ, however,
from those of Grange Hill not only in the amount of their dip, but
also in its direction, for they appear to dip to the north-west.

VIII. Summary or Conclusions AS REGARDS THE
Ieneous Rocks.

Taking Grange and Allen Hills together, four groups of rocks may »
be made out :—

(1) Rocks with abundant felspar-needles in the groundmass,
showing good fluxion-structure: as, for example, the ande-
sites of the northern foot of Grange Hill.

(2) Rocks with the groundmass largely formed of fair-sized,
often fresh, square-edged crystals, including, as a rule, also
rhombic pyroxene and patches of hematite: as, for ex-
ample, the greenish hypersthene-augite-andesite [67, 78]
high up on the Hill of Allen and sometimes of Grange Hill.

(3) Rocks with a groundmass formed of a crystalline matrix of
felspar and augite, the latter not in definite crystals, but
filling up the spaces between the felspars; very large
labradorites and some serpentine present: as, for example,
the porphyritic basalts of both Grange and Allen Hills
[5, 73}.

(4) Rocks aa a fairly plentiful groundmass consisting of
felspar-needles and some augite aud magnetite; the
porphyritic constituents consist of much-altered felspars
and large fresh augites, often aggregated together in
groups: as, for example, the basalts found along the eastern
base of the Hill of Allen and some of those of Grange Hill.

Q.J.G.8. No. 208. Q7

604 MESSRS. 8. H. REYNOLDS AND C, I. GARDINER [Nov. 1896,

The general arrangement of the igneous rocks of Grange and
Allen Hills may be shown in the fo lowing synopsis :—

At the top:

GRANGE. ALLEN,

5. Andesite forming a small patch 5. Variable rocks, the best-marked
overlying the porphyritic basalt being the hypersthene-augite-
towards the south-western end andesite having a groundmass
of Grange Hill. crowded with square or rect-

angular felspars.

4. Porphyritic basalt. with large 4. Porphyritic basalt, with large
erystala of labradorite. erystals of labradorite.

3. Basalt, sometimes amygdaloidal, 3. Basalt, sometimes amygdaloidal,
sometimes with large fresh sometimes with large fresh
augites. augites. Its colour is red or

dark green, and it occurs along
the south-eastern face of the hill.

2. Augite-andesite, often showing 2. Not seen.
good fluxion-structure.

1. Band of ash seen along the 1. Not seen.

northern foot ; below it, at two
points, lava is visible.

IX. Grnerat Conciusion AND SUMMARY.

All the rocks exposed in the Kildare inlier are either of Silurian
or of Ordovician age. Those lying west of the fault which runs
between Dunmurry Hill and the Chair are probably of Silurian age,
while the fossiliferous beds east of the fault show that we are here
dealing with rocks of Ordovician age. With the doubtful exception
of one exposure of grit, all the beds east of the fault are referable
to the Middle Bala.

Grange Hill and the Hill of Allen are mainly composed of con-
temporaneous igneous rocks, all the lavas being of the nature of
basalts or andesites. We found no clear evidence of the occurrence of
intrusive rocks anywherein theinlier. The igneous rocks of Grange
Hill are overlain and underlain by sedimentary deposits containing
Middle Bala fossils. With regard to the age of those of the Hill
of Allen, we have no definite evidence; but their resemblance to
those of Grange Hill is so great that we feel justified in regarding
them, and so the whole of the igneous rocks of the area, as of the
age of Sedgwick’s Middle Bala.

We wish to express our best thanks for kind help to Messrs. Marr
and Harker, and especially to Mr. W. W. Watts and Mr. Cowper
Reed; also to Prof. Sollas and various members of the Irish Geological
Survey, for the privilege of referring to the Survey Maps at Dublin.
Also to Mr. P. Doyle, of the Chair Farm, Kildare, for his uniform
courtesy.

Quart. Journ.Geol.Soc.Vol.LII.P1. XXVIII

F.H.Michael del.et lth. Mintern Bros.imp.

LAVAS AND ASHES
FROM THE KILDARE INLIER.

Vol. 52.] ON THE KILDARE INLIER. 605

EXPLANATION OF PLATE XXVIII.
[The numbers in square brackets indicate spots marked in the maps. |

Fig. 1. Olivine ?-basalt [8], Grange Hill, Kildare. x 35.

The dark patch is a pseudomorph of hematite and another red
oxide of iron, probably after olivine. The drawing shows also crystals
of augite and of altered felspar. The groundmass consists of felspar-
needles, small patches of augite and iron ores.

Fig. 2. Porphbyritic basalt [73], Hill of Allen. x 9.

The groundmass consists mainly of small felspar-crystals and
fresh grains of augite in nearly equal proportions. The porphyritic
constituents consist of very large, much-altered crystals of labradorite,
and rounded erystals of augite, two of which are shown in the upper
part of the drawing.

Fig. 3. Augite-andesite [78], Hill of Allen. x 9.

The drawing shows a large twinned crystal of augite, the central
portion of which is intimately intergrown with a pale rhombic
pyroxene. The augite encloses also several small patclies of magnetite.
The character of the groundmass is similar to that of fig. 6.

Fig. 4. Andesite-tuff [30], Grange Hill, Kildare. x 23.

The drawing shows angular fragments of two varieties of andesite
embedded in a matrix of smaller fragments, broken felspar-crystals,
and fine particles.

Fig. 5. Amygdaloidal augite-andesite [29], Grange Hill, Kildare. x 9.

The groundmass consists mainly of small felspar-needles, and shows
good fluxion-structure. Embedded in it are numerous amygdules of a
chloritic mineral and quartz. The larger amygdules, which are more
or less circular or oval in section, have a rim of quartz, while the
main part is occupied by the chloritic mineral.

Fig. 6. Augite-andesite [68], Hill of Allen. x 9.
The drawing shows numerous small, square-edged felspars, also larger
porphyritic felspars, which are greatly altered, but are bordered by
a rim of fresh secondary felspar.

Fig. 3 is the only one in the Plate drawn in polarized light.

Discussion.

-Mr. W. W. Warts called attention to the presence of olivine and
hornblende in the contemporaneous igneous rocks of Kildare. The
former mineral was almost unknown, and the latter decidedly rare,
in the great Welsh province of this date.

The Present and Mr. Garpiver also spoke.

272

606 PROF. J. P. IDDINGS ON EXTRUSIVE [ Noy. 1896,

30. ExtrustvE and Intrusive Ienzous Rocks as Propvucts of
Maemaric Dirrerentration. By Prof. J. P. Inprnes, For.Corr.G.8.
(Read June 24th, 1896.)

[Puate XXTX.—Map. |

Pror. W. C. Broacrr, in dedicating to me his recent work on ‘ Die
Eruptionsfolge der triadischen Eruptivgesteine bei Predazzo in
Sudtyrol,’! has not only honoured me by this token of his friend-
ship, which I prize highly, but also by associating my name with a
work which commands my admiration, and with which I am in the
most hearty accord. His treatment of the igneous rocks in the region
of Predazzo as a generic series intermediate in composition between
a granite-diorite-gabbro series and a granite-syenite (eleolite-syenite)
series is fully justified by their chemical and mineral composition
and by their geological association; and for the order in which
these rocks have been erupted he has given ample evidence. The
intrusive character of the granular rocks is clearly established, and
the fantastic theory of Reyer abundantly disproved. So also the
discussion of Kjerulf and Michel-Lévy’s hypotheses, regarding the —
melting and assimilation of overlying rocks by molten granitic
magmas, leaves nothing to be said in further refutation of these
suggestions, so far as they relate to the intrusion of igneous magmas
that come within the range of our investigation. To suppose that
such a process may have been active in the earliest period of the
cooling globe is quite reasonable. It implies a very highly-heated
magma, and shifting temperature or convection-currents. As
applied by Suess” to account for the great craters of the moon, it
appears highly probable. But there is no evidence that such a
melting has taken place in the case of the intrusion of igneous rocks,
except to a very limited extent. The remarks of Brogger on this
subject also express the conclusions of those who have studied
the phenomena of intrusive rocks in the United States.

In his closing argument relating to the order of eruption, and to
the differentiation of igneous magmas as exemplified in groups of
intrusive and extrusive rocks, he reaches, however, conclusions which
are different from those to which a study of the igneous rocks in
certain parts of Western America must necessarily lead one. And
since he has cited the occurrence of igneous rocks at Electric Peak
and Sepulchre Mountain in the Yellowstone Park * in support of his
position, it is only right that I should explain, more fully than I

+ «Die Eruptivgesteine des Kristianiagebietes.’ II. Videnskabs-selskabets
Skrifter I. Mathematisk-natury. Klasse, 1895, no. 7.

? Suess, E., ‘Einige Benerkungen wber den Mond,’ Sitzungsb. d. k. Akad. d.
Wissensch. Wien, vol. civ., Feb. 1895.

3 Iddings, J. P., ‘The Eruptive Rocks of Electric Peak and Sepulchre
Mountain, Yellowstone National Park, 12th Annual Report U.S. Geol.
Surv., pp. 069-664, Washington, 1821.

————— eS OO ee ee eee

Mel. 52.] AND INTRUSIVE IGNEOUS ROCKS. 607

did in the description of those rocks, the relation of that series of
eruptions to the whole series of which it is but a part.

Prof. Brégger says in effect that he has considered only the case
of the order of eruption of deep-seated rocks ( /%efengesteine) because
they alone can furnish a correct idea of the primary differentiation
which takes place in the primitive magma or in the ‘magma-basin.’
For after certain portions have been separated from the primitive
magma by being erupted into deep-seated parts of the earth’s crust,
further differentiation may take place in this portion producing
basic and acid complementary rocks, which may be further erupted
in the form of dykes, or may be extruded upon the surface of the
earth. And since this may take place in each deeply-seated body
of magma, separated successively from the magma-basin, there may
be in one region successive, or repeated, series of eruptions in which
the rocks range from basic to acid. ‘The order of succession of this
cumpounded series of eruptions would not be the same as that of
the series of eruptions emanating from the so-called magma-basin.
And the characters of the rocks produced by the subsequent dif-
ferentiation of the separate magmas, derived from the primitive
magma, may be distinct from those produced by the direct differ-
entiation of the primitive magma. For this reason, results obtained
by a study of the order of succession of extrusive rocks must be
critically examined before employing them to explain the order of
eruption or the character of the differentiation of primitive magmas,
or of those in so-called magma-basins.'

1 *Tm Obigen ist nur von der Eruptionsfolge der Tiefengesteine die Rede
gewesen. Hs ist nach meiner Ansicht absolut nothig, bei der Ableitung der
gesetzmassigen Beziehungen der Altersfolge der einer Eruptionsepoche zu-
gehorigen Eruptivgesteine, nicht ohne weiteres die Erfahrungen von den Verhalt-
nissen der Tiefengesteine auch auf die Hrgussgesteine, und umgekehrt, zu
uibertragen.

‘Bei den Ganggesteinen ist es schon jetzt eine allgemeine Erfahrung, dass
Gruppen von basischen und sauren Ganggesteinen als complementire Gange
den verschiedenen Eruptionen der Tiefenmassen entsprechen. Innerhalb der
Geschichte der ganzen Hruptionsepoche wirden wir somit fiir die Ganggesteine,
wenn diese allein beriicksichtigt werden sollten, eine oft wiederholte Aut-
einanderfolge von basischen und sauren Gesteinen als die normale Eruptions-
folye bezeichnen miissen.’

e . . . . . . . . . . . . . . o . . . a . a . .

‘Nun ist es aber selbstverstandlich nicht nur denkbar, sondern im Allge-
meinen sogar sehr wahrscheinlich, dass dieselben Spaltungsmagmen, welche in
den Gangspalten als hypabyssische Gesteine erstarrt sind, theilweise auch die
Tagesoberfldche erreichen konnten und hier oft mit anderer Mineralienzusammen-
setzwng wnd Structur, als Ergussgesteine, als Decken und Strime etc. erstarren.

‘In derartigen Fallen wurden wir bei der Bestimmung der gegenseitigen
Altersbeziehungen der einer bestimmten Eruptionsepoche angehorigen Erguss-
olin wieder eine Altersfolge von basisch—sauer, etc., mit mehrmals wieder-

oltem Wechsel erhalten konnen.

‘Die Altersfulge der primaren Differentiationen, die Reihenfolge der
primaren Aufpressungen der differenzirten Magmen aus dem Magmabassin
selbst wiirden wir aber wieder nicht erhalten. Diese lasst sich allein durch
das Studium der Altersbeziehungen der grossen Massen der Tiefengesteine
ableiten.

‘ Aus diesem Grund miissen die Untersuchungen iiber die relativen Alters-

608 PROF, J. P. IDDINGS ON EXTRUSIVE [Nov. 1896,

The statement is made that the order of eruption of extrusive
rocks is for the most part dependent on relatively secondary differ-
entiation. It is also stated that the order of primary differentiation
and the succession of primary eruptions of the differentiated magmas
from the ‘magma-basin’ can be learned only from the study of
the relative ages of the great masses of deep-seated rocks.

Prof. Brogger then comments at some length upon the general
order of eruption as set forth by me in the paper on ‘The Origin
of Igneous Rocks,’ namely, that the succession is generally from
rocks of intermediate to those of more and more extreme com-
position.’ And he calls attention to the fact that the conclusions
were drawn almost entirely from observations upon extrusive rocks.
In these cases also he notes numerous exceptions, and moreover
points out that the parent magmas (Stamm-magma) may not always
be of like composition. These points, too, were mentioned in the
paper cited (pp. 178, 183).

Upon some of the propositions in question Prof. Brégger and I
are in perfect accord, in others we seem to be at variance. We
agree as to the fact that the differentiation of magmas intruded
into the earth’s crust from greater depths produces complementary
rocks, which may take the form of dykes (Rosenbusch’s Ganggesteine)
or may reach the surface as lava-streams, etc.; that the order of
eruption of these products may lead to recurrent series, both among
intrusive and among extrusive bodies ; that these series, as a whole,
would not represent the differentiation that took place in the
original parent magma. All parent magmas do not have the same
composition. The magmas first derived from them certainly do not
have the same composition, consequently the groups of differentia-
tion-products belonging to various derived magmas will present
distinct series. And of course the intermediate member of one of
these series is like the magma from which the series was directly
derived. It has not a fixed composition corresponding to one inter-
mediate for all known rocks.

Eruptions from a body of molten magma into outlying or
overlying regions may take place before a differentiation of this
particular magma sets in, or after it has progressed little or much.
The composition of the various portions of magma drawn off will
depend on a variety of conditions, which might be postulated at
length. If extrusive bodies of rock be considered apart from their

beziehungen der Ergussgesteine immer mit kritischer Vorsicht benutzt werden,
wenn man die Differentiationsgesetze der Tiefenmagmen und ihren Einfluss
auf die Altersfolge der Eruptionen einer Eruptionsepoche studiren will; in
der obigen kurzen Ubersicht wurden deshalb auch fast ausschliesslich bekannte
Beispiele der Altersfolge plutonischer Gesteine beriicksichtigt, wakrend die
Altersfolge der Ergussgesteine als zwm grossen Theil von relativ sekundéren
Differentiationen abhdngig, vorlaufig ausser Acht gelassen wurde.’ (Op. jam
cit. pp. 177, 178.)

1 Iddings, J. P., ‘The Origin of Igneous Rocks,’ Bull. Phil. Soc. Washington,
vol, xii, (1892) p. 145.

Vol. 52. | AND INTRUSIVE IGNEOUS ROCKS. 609

proper intrusive connexions, it is clear that, since all the portions
of magma erupted from a reservoir of magma may not reach
the surface of the earth, the series of lavas which have been
extruded may be a partial series, imperfect at the beginning or
end, or anywhere between. And the same must be true for any
disconnected group of intruded bodies.

On all these points we agree. The points of difference seem
to be the following:—That the order of primary differentiation and
eruption can be learned only from a study of large bodies of dee;-
seated igneous rocks ; and conseyuently that the bodies of extrusive
rocks from which my conclusions were drawn are not adequate for
the solution of the problem; that the range from intermediate to
greater and greater extremes is not of very general application, and
that the order of succession of the rocks at Electric Peak represents
amore general law, namely, that the succession is usually from
basic to acid, often followed by basic as the last.

In order to defend my position from this friendly attack, it is
necessary to picture as vividly as I can the relation of the igneous
rocks at Electric Peak to all those that took part in the great
series of eruptions which occupied almost the whole Tertiary period,
and spread themselves over an enormous territory lying in Montana,
Wyoming, and Idaho.

The extent of this great period of volcanic activity, though vast,
is well marked in this region.’ During the longer periods of time
during which Paleozoic strata were being deposited, no outburst of
igneous rock took place. The same is true tor all the Mesozoic
period until after the Laramie coal-bearing layers had been formed :
the whole of this great series being nearly contormable throughout.
At the end of Cretaceous time, there were great orographic move-
ments, by which the region was profoundly faulted and dislocated.

Volcanic action began at this time, and fragments of igneous
rocks are included in the sandstones immediately overlying the
coal-bearing Laramie.” There was also extensive denudation
whereby the sedimentary strata were in places entirely removed from
off the underlying crystalline schists. Into these disturbed strata
the igneous material was forced, and upon the uneven surface of
the country it was spread out, covering crystalline schists in one
place, and upturned limestones and sandstones in another. In most
cases the character of the eruptions was extremely violent. At
first they were largely explosive, shattering the surface-rocks,
whether gneiss or limestone, and scattering them broadcast to form
the first layer of tuff-breccia, or to be intimately mingled with
fragments of lava. The explosive character prevailed until a great
accumulation of tuff-breccia formed a chain of lofty voleanoes com-

1 Hague, A., ‘Geological History of the Yellowstone National Park,’ Trans.
Am. Inst. Mining Engineers, vol. xvi. (1888) p. 783; also Compte-rendu 5éme
Sess. Int. Congr. Geol. Washington, 1891, p. 338, and ‘‘lhe Age of the Igneous
a of the Yellowstone National Park,’ Am. Journ, Sci. ser. 4, vol. i. (1896)

° ov. :
ae Weed, W. H., ‘The Laramie and the overlying Livingston Formation in
Montana,’ Bull. U.S. Geol. Surv. No, 105, pp. 12 & 21, Washington, 1893.

610 PROF, J. P. IDDINGS ON EXTRUSIVE [Nov. 1896,

parable with those of the Andes in size, as well as in the nature of
their material. The later eruptions from these volcanoes were
quieter outflows of lava, which probably took place after the
position of the volcanic conduits had become more stationary.
Erosion having carried away the upper parts of these great cones,
the remaining portions are almost wholly made up of breccia, in
places 4000 feet thick.

The last of the great eruptions were equally violent, though of a
different kind. They were gigantic fissure-eruptions that flooded
the region west of the chain of denuded volcanoes with massive
streams of lava that rose high up on the flanks of the surrounding
mountains, and then flowed toward the south-west, leaving, when
cooled and after erosion had somewhat reduced the surface of the
stream, a vast sheet of lava at least 1000 feet thick in most places,
and over 2000 feet thick in some parts. This was followed by
other outflows from fissures that flooded the region for hundreds of
miles to the south-west and west, and closed the period of activity.
Within the Yellowstone Park the earliest breccias were accumulated
in Hocene time, and the great bulk of the Absaroka volcanoes in
Miocene; while the great fissure-eruptions just mentioned took
place in the Pliocene.

With this crude sketch before us, let me attempt to fill in, as it
were, some of the details. To this end I have drawn an outline-
map of the territory involved, indicating only the drainage and the
surface-distribution of the volcanic rocks. The chain of volcanoes
which is now represented by the tuff-breccias and included lava
sheets, dykes, stocks, etc., extends without interruption from imme-
diately south of Bozeman, Montana, at about lat. 45° 30’, south-
ward 40 miles in the Gallatin Mountains, to a short distance within
the northern boundary of the Yellowstone Park.’ It extends east-
ward about 50 miles through the southern half of the Snowy
Mountains along the northern boundary of the Yellowstone Park,
to the head-waters of Clark’s Fork River. Thence southward in
Wyoming it forms the Absaroka” range along the eastern boundary
of the Park,’ and continues beyond the head-waters of the Yellow-
stone River to the head-waters of Wind River, where it forms the
rugged peaks about Togwotee Pass and the Washakee Needles,*
terminating at about lat. 43° 30' N., or 105 miles from the last-
mentioned bend. The length of the chain is about 170 miles. In
the north it is at present 12 or 15 miles wide, and in the Absaroka
range from 25 to 50 miles wide. The volume of igneous rock that
was erupted to form this range must have been enormous, when

1 Tddings and Weed, ‘Livingston Folio, Geologic Atlas of the United
States,’ no. 1, Washington, 1894.

2 Misprinted ‘ Assaroka’ in the accompanying map (Pl. XXIX).

5 Hague, A., Compte-rendu 5eme Sess. Int. Geol. Congr. Washington, 1891,
p- 839; also Iddings, ‘A dissected Volcano of Crandall Basin, Wyoming,’
Journ. Geol. vol. i. (1893) p. 606.

4 St. John, O., Report in Hayden’s 12th Ann. Rep. U.S. Geol. & Geogr.
Sury. of the Territories, pt. i. p. 260, Washington, 1883.

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Vol. 52. ] AND INTRUSIVE IGNEOUS ROCKS. 611

we remember that the Crandall volcano represented a pile of voleanic
material at least 13,500 feet high, and that there were others like it.
The present surface-extent of this range of volcanoes is over 4000
square miles, and the present thickness of the breccias is from
2000 to 4000 feet. When the great erosion from the summits is
taken into account, and the shrinkage of its borders from denudation
and by being covered by subsequent fissure-eruptions is included,
an original volume of 4000 cubic miles is an estimate within the
bounds of reason.

Almost the whole of this material is andesite and andesitic basalt,
ranging in percentage of silica from 65 to 52. The parts that
would lie outside of these limits do not constitute 1 per cent. of
the whole, so far as my knowledge and judgment go. Small bodies
with exceptional composition occur, and will be referred to again,
But the great mass of the mountains consists of hornblende-mica-
andesites, hornblende-andesites, hornblende-pyroxene-andesites,
pyroxene-andesites, olivine-bearing andesites, and andesitic basalts.

These have been erupted in the following order :—First, horn-
blende-mica- and hornblende-andesites with some dacite, forming
light-coloured, mixed breccia, usually containing fragments of crystal-
line schists and of sedimentary rocks. The volume of this breccia is
small when compared with that of the overlying dark-coloured and less
siliceous breccia. Its average percentage of silica would be about
62. It has suffered some erosion before being covered by the second
breccia, but appears to grade up into it in places. The overlying
breccia grades upward from hornblende-pyroxene-andesite through
pyroxene-andesite to andesitic basalt, the least siliceous varieties
being uppermost. The proportions of these varieties are about
equal, and together they form about one-half the whole mountain-
range, beginning at the northern end—that is, originally about
2000 eubic miles. Upon the basaltic top of this series was ejected
a second series almost identical with the first. This later series con-
stituted the remaining half of the mountain-range, and formed
volcanoes that have been eroded in the same manner as those
farther north. In each of these series of eruptions the variation
was from more siliceous to less siliceous; and the range of silica-
percentages is from about 65 to about 52: the average percentage
in each case being probably about 57 or 58,

With these accumulations of andesitic breccias are a number of
bodies of intrusive rock, whose bulk, however, is quite insignificant
when compared with that of the breccias. These intrusive bodies
occur partly within the breccia, partly within the sedimentary
strata and the crystalline schists beneath the breccia. They have the
form of laccolites, intrusive sheets, dykes, and stocks, and embrace
coarse-grained, medium-grained, and aphanitic rocks. Their relation
to the andesitic breccias is clearly shown in most instances.

The largest of these intrusive bodies occur in the sedimentary
strata of the Gallatin Mountains, south of Electric Peak.’ One

1 «The Eruptive Rocks of Electric Peak, etc.’ 12th Ann. Rep. U.S. Geol.
Surv. p. 578, Washington, 1891.

612 PROF. J. P. IDDINGS ON EXTRUSIVE [Nov. 1896,

forms a laccolite in Cambrian strata immediately over gneiss. Its
volume was about 17 cubic mile, and its silica content is 61 per cent.
It is traversed by a second plug-like intrusion, whose volume was
probably 2 cubic miles: the average silica content of this mass is
about 70 per cent. A third body of intrusive rock is like the first in
composition, having about 65 per cent. of silica. These are the oldest
intrusions exposed in the Gallatin Mountains. The intrusive sheets
connected with the last-mentioned bodies traverse Electric Peak
and are older than the eruption of igneous rocks that rose through
the conduit there and reached the surface as andesitic breccias, and
filled dykes and the stock with porphyries and diorite. At this
place the intrusive and extrusive series are directly connected, and
the two groups correspond in the order of their eruption. The
rocks flowing through the conduit appeared on the surface as horn-
blende-pyroxene-andesites cut by a dyke of basaltic andesite, and
by more siliceous andesite-porphyries, ending in dacite: the in-
trusive series ranging from diorite to quartz-mica-diorite and
granite. The yolumes of these bodies are small, the cross-section
of the core being about 3 square mile.

In the neighbourhood of Haystack Mountain, at the head of
Boulder Creek, Montana, the sheets intruded into the Cambrian beds
are acid andesitic porphyries, which appear to have been connected
with the earliest eruptions of acid andesitic breccias. In the core
of the Haystack volcano the intruded mass is gabbro-diorite,
varying in different parts between these two varieties of rocks. It
is cut by a few small dykes of more siliceous rock. The region
about Emigrant Peak contains several large bodies of dacite and
dacite-porphyry that burst up through the basic andesitic breccia.
The superficial extent of these intrusive bodies approaches 40 square
miles, and their volume was probably 20 cubic miles.

The core of the Crandall volcano consists of gabbro, passing into
diorite, with a constantly increasing acidity, the last intrusions
being granite. The cross-section of this core is about 14 square
mile, and, if 10,000 feet deep, its volume was about 3 cubic miles.
The most siliceous portions are relatively very small. The dykes
which radiate from this core are mostly formed of rocks correspond-
ing to gabbro in chemical composition, only a few correspond to
the diorite, and none were found which were equivalent to the
granite. Some, however, occur more basic than the gabbro, and
there are complementary dykes of absarokite and banakite.* In the
breccia in places are the lava-flows corresponding to these comple-
mentary dykes, but their volume is quite insignificant. ‘There are
similar occurrences of dykes and superficial lava-streams throughout
the range of mountains to the south.

The eruptions of these intrusive rocks were contemporaneous
with those of the andesitic breccias, in many instances, and occurred
within the period during which the volcanic range was built. They
have suffered erosion together with this range. The coarse-grained

1 Op. cit. p. 609.

2 Iddings, ‘ Absarokite-Shoshonite-Banakite Series,’ Journal of Geology,
vol. iii. (1895) no. 8.

Vol. 52.] AND INTRUSIVE IGNEOUS ROCKS. 613

gabbros and medium-grained diorites and granite solidified at con-
siderable depths below the surface, and might very properly be
classed as ‘ deep-seated’ or ‘ abyssal rocks,’ if we use that term. The
laccolitic rocks are typical, and would seem to belong to what
Prof. Brégger calls hypabyssal. But in this region the one
kind are just as deeply seated as the other, and in some cases the
laccolites are more deeply-seated than the coarse-grained rocks in
the cores. So that for these intrusive rocks the terms ‘ abyssal’ and
‘hypabyssal,’ if applied with any geological significance, would not
fit groups of these rocks, which might be made to accord with
textural differences. Moreover, while it is possible to consider the
order of eruption of the intrusive rocks apart from that of the
extrusive rocks, such a method would not seem a comprehensive
one.

Leaving the discussion of this matter for the present, let us
continue our review of the history of volcanic activity in the whole
region. After the close of activity along the chain of andesitic
volcanoes, denudation set in on a grand scale, and the lofty moun-
tains were cut to pieces by the running waters that drained their
slopes. A long time must have been consumed in reducing them to
nearly their present configuration. How long this was we have
no other means of judging than by considering the amount of this
erosion, which reduced the height of the Crandall volcano some
10,000 feet.

When volcanic activity again broke out, its seat was shifted west-
ward, and its character was changed ; there were no longer scattered
explosions from what was probably a line of faulting or fissures, but
the gushing forth of gigantic floods of lava, whose composition was
quite different from the bulk of those that built up the range of
andesitic voleanoes. That this outflow must have been through
some great fissure or set of fissures its volume and form, and its
relation to the surrounding mountains, clearly attest. Moreover,
we have in the fissure-eruption in Iceland in 1783 an indication
of what took place in this region. The fissure in Iceland was
12 miles long, and the lava that poured out flowed in streams 45 and
50 miles long, in places forming lakes 12 and 15 miles wide, and
100 feet deep, and in a gorge 200 feet wide reaching a thickness of
600 feet. The total volume of the lava has been estimated as
greater than that of Mont Blanc.’

Some idea of the flood that broke forth west of the volcanic chain
in Wyoming may be gained by considering that its present extent is
50 miles from east to west, and from north to south it is exposed
to view for 90 miles. But its south-western boundary is unknown,
since it is covered by still more recent lava. Throughout this vast
extent, more than 2000 square miles, it is an unbroken sheet,
whose depth in the central portion is unknown, but is more than
1000 feet, and in some places more than 2000 feet. It forms the
great plateau of the Yellowstone Park, and the region south-west of it

? Arch, Geikie, ‘ Text-book of Geology,’ 3rd ed. 1893, p. 222.

614 PROF, J. P. IDDINGS ON EXTRUSIVE [Nov. 1896,

in Idaho. In this direction it descends in a series of great terraces,
and continues at lower altitudes for unknown distances down the
broad plain which forms the valley of the Snake River. It has been
followed for some distance down the channel of Falls River, which
has cut through the capping of basalt, and extends along the western
base of the Teton range to Pierre’s Hole, where it underlies basalt.’
And similar lava is exposed underlying the same basalt-sheet 150
miles to the south-west down the Snake River at Shoshone Falls.*
No proper estimate of the volume of this rhyolitic lava can be made,
but, judging from the area exposed, its volume is much more than
400 cubic miles.

This rhyolitic lava is quite uniform in its composition; the
average silica-percentage is about 74. Its eruption may have
occupied a long time, but evidences of repeated outbreaks are not
numerous, and much of the lava belonged to single flows, since
cations 1000 feet deep cut through a continuous body of rock in
most cases.

Closely connected with the eruptions of this rhyolite-lava were
others of basalt. Not only is there no evidence of any extensive
period of erosion separating the eruptions of one from that of the
other, but streams of basalt immediately underlie the rhyolite in
places, resting on the greatly eroded surface of the long-extinct
volcanoes. Basalt-streams in rare instances lie between rhyolite in
such a way as to prove their comparative contemporaneity. But
the great bulk of the basalt poured out immediately after the rhyolite.
Its eruption was also from fissures, still farther south-west and
west. And the result was the flooding of all the great plain that
stretches westward through Idaho along the line of the Snake River.
The extent and thickness of this enormous sheet of basalt can only
be guessed at, so little is known at present of its boundaries. That
it is practically continuous as a covering for the country, and that
it rests immediately upon the great rhyolite flood, are both well-
established facts; also that it was the last great outburst of lava in
this region, and closed the series of Tertiary eruptions in this part
of the world. Its eruption undoubtedly took place from many
fissures. Any estimate of its volume must be wide of the truth,
but when we consider that the area of country known to be covered
by it is much more than 300 miles long from east to west, and 50
to 60 miles wide, or more than 18,000 square miles, and when we
consider what thicknesses have been observed in the canon cut
through it, an average thickness of 200 feet must be well within
the limits of truth. With this thickness its volume is at least
700 cubic miles,

In this region, then, we have bodies of extrusive rock of great
magnitude, to be reckoned in hundreds of cubic miles, and bodies
of intrusive rock of much less magnitude, but of no mean propor-

1 Bradley, F. H., Report in Hayden’s 6th Annual Rep. U.S. Geol. Surv.
2 King, C., U.S. Geol. Expl. 40th Parallel, vol. i. p. 592 (Systematic
Territories, pp. 213-215, Washington, 1873.
Geology), Washington, 1878.

Vol. 52.] AND INTRUSIVE IGNEOUS ROCKS. 615

tions, whose volumes may still be estimated in cubic miles. There
are besides many bodies of comparatively small size, both extrusive
and intrusive. To the first category belong the andesites of various
kinds, rhyolites and basalts; to the second, the medium-grained
and coarse-grained granular rocks and porphyries; while to the
third belong any of these, and the exceptional varieties such as
absarokites, shoshonites, and banakites. All are inseparable parts
of the volcanic history of the region in Tertiary times, and their
testimony as to the sequence of events is necessarily concordant.
From it we learn that the earliest eruptions were of magmas which,
as laccolites, became hornblende-mica-andesite-porphyry, and as ex-
trusive rocks became hornblende-mica-andesite ; with these magmas
were associated hornblende-andesites and porphyries, and some
that might be classed as dacite. Later there were great eruptions
of magmas solidifying as pyroxene-andesites of several kinds, or as
diorite, followed by those yielding andesitic basalt, and basalt or
gabbro.

We find at one volcano, that of Electric Peak and Sepulchre
Mountain, a succession of more and more siliceous magmas follow-
ing those of diorite and pyroxene-andesite, reaching dacite. In the
region of Emigrant Peak and Mill Creek numerous and large bodies
of dacitic porphyry, or acid andesitic porphyry, traverse the basic
andesitic breccia. At Crandall volcano there was first acid andesite,
then basic andesite and andesitic basalt. Then in the core of the
volcano we have a reversal of the series, after the basaltic magma had
crystallized as gabbro, yielding diorite and granite in small volumes.
But away from the core occur complementary basic dykes. In
these volcanoes we find evidence of a quite local differentiation,
yielding smaller volumes of magmas, becoming more and more
extreme, and furnishing an aplite in the core, and at Crandall
volcano the basic complements at a distance.

There is a repetition of this history in the extrusive breccias
forming the southern half of the range. Then a long period of
rest, followed by sudden and violent eruptions on a scale almost
without parallel, producing two distinctly marked and contrasted
types of magma, rhyolite and basalt, whose combination would
reproduce a magma like that with which the first eruptions began.
Furthermore, while they closed the period of activity, the com-
positions of these magmas are not so extreme as are those of
some of the small bodies of magma that closed the eruptive activity
centred about some of the great volcanoes just mentioned. If they
represent the products of a differentiation, as I believe they do,
the differentiation was not so extreme, or possibly not of the same
kind, as that which took place at the base of one of the volcanoes.

In the assemblage of activities that occurred in Tertiary time in
this region, there must have been processes of differentiation of
different orders; some taking place in large reservoirs of magma,
others affecting smaller ones, some in deeply-seated magmas, others
in magmas nearer the earth’s surface. The differentiation was
undoubtedly due to a disturbance of the physical equilibrium pre-
viously existing between the molecular constituents of the magma,

616 PROF. J. P. IDDINGS ON EXTRUSIVE [Nov. 1896,

the most natural causes for which disturbance seem to be changes
of temperature, and possibly of pressure. And we should expect —
the most marked results where these changes were the greatest.
We should expect to find the greatest changes for a given period
of time experienced by magmas introduced into the cooler parts
of the earth’s crust; it being understood that differentiation will
take place the more readily, the more liquid the magma; and take
place, if at all, before the magma solidifies. We should then expect
a differentiation in the most deeply-seated magma to progress the
most slowly, other things being equal; and further that it would
be less likely to reach such an extreme as that attained by a magma
nearer the earth’s surface. But the chemical nature of the original
magma must have a marked influence on the results, and it seems
to the writer that magmas richer in alkalies are more readily differ-
entiated, and produce more extreme results.

The suggestion of Prof. Pirsson’* that at a volcanic centre the
hotter part, being at the centre of the reservoir, would be the locus
of the more siliceous products of differentiation, while the cooler
margin would contain the least siliceous products, has a direct
bearing upon the order of succession of eruptions within the centre
of a volcanic core, and is applicable to the Crandall volcano.

The elaboration of the processes of differentiation, and of the
eruption of the resulting magmas, necessitates many considerations
involving the size, position, and shape of the reservoir, and possible
differences of temperature ; the times of eruption, size, and shape of
the conduit, and the laws controlling the flow of liquids. For, with
varying viscosities in the several parts of a differentiated magma,
the relative liquidity of the parts will influence the order of eruption
according to the size of the conduit and the velocity of the flow.
The operation of so many factors must prevent uniformity in the
results of volcanic activity, but may permit numerous repetitions in
different localities of closely analogous series of results.

If there be fundamental or primary as distinguished from
subsidiary processes of differentiation, and if the former be con-
sidered to affect the most deeply-seated magmas, while the subsidiary
processes take place in smaller reservoirs of magma nearer the surface
—and if these processes find expression in the magnitude of the bodies
of derived magma, and in the order of their eruption—then some
idea of the relative order of those processes which gave rise to the
many bodies of igneous rocks that constitute so great a feature in
the geology of the region just described may be gained if we climb
to the summit of a commanding peak in the Teton range and look
about us over the surrounding country. Standing, as we may be,
at an elevation of 13,000 feet above sea-level, and 7000 feet above
broad valleys to the east and west, with the Teton Mountains
descending rapidly below us to the north, we have an uninterrupted
view of the region of volcanic activity. Directly east the remnants
of the once lofty chain of andesitic volcanoes rise in a range of
rugged mountains, sombre in the colour of their barren crests, which

1 Pirsson, L. V., ‘Complementary Rocks and Radial Dykes,’ Am. Journ.
Sci. ser. 3, vol. 1. (1895) pp. 116-121.

Vol. 52.] AND INTRUSIVE IGNEOUS ROCKS. 617

reach altitudes of 9000 and 12,000 feet. We are nearly opposite
the southern end of the range, the nearest peaks being 40 miles off,
and its breadth about 50 miles. As the eye follows the western front
of the range northward, it gradually sinks behind the level-topped
plateau, until only the higher peaks are visible. These may be
traced westward across the northern boundary of the Yellowstone
Park to Electric and Emigrant Peaks, beyond which our imagina-
tion alone can follow them to their northern end, 140 miles distant.
Remembering how much of this range is extrusive rock, and trying
to locate those spots where intruded stocks have been discovered,
whose relations have been greatly magnified by the process of
detailed study and description, we are impressed with their insigni-
ficance when compared quantitatively with the breccias in which
they occur.

The great rhyolite-plateau, with its monotonous covering of pine
forest, occupies the foreground northward, stretching from the base
of the Teton Mountains to the north-east, north, and north-west,
for distances of 50 and 70 miles, and descending in great terraces
towards the valley of the Snake River. The whole 2000 square miles
lies before us as a map, greatly foreshortened, with boundaries
outlined by mountains on the east, north, and west. Turning our
faces westward, we look down across the broad open valley of the
Snake River, into which the western slopes of the Tetons gradually
descend. The farther side is 100 miles away, and beyond our
horizon this vast intermontane plain continues se ae for
hundreds of miles—all basalt.

Surely the depths at which these once molten floods of rhyolite
and basalt were differentiated must have been profound, and the
processes of their differentiation, when compared with those which
produced the small bodies of magma in the conduits of the Electric
Peak and of the Crandall volcanoes, must have been the more
fundamental.

There are, then, in this region extrusive rocks, whose volumes are
of such magnitude that the evidence drawn from the succession of
their eruptions and from their composition is of a higher order than
that derived from the lesser and more localized eruptions, whose
volume, however, may be estimated in cubic miles. It is upon
evidence of this order that I ventured to enunciate the principle,
that in a region of eruptive activity the succession of eruptions
commences in general with magmas representing a mean composition
and ends with those of extreme composition.

Pruatze XXIX.

Geological Sketch-map of portions of Idaho, Montana, and Wyoming, showing
in part the distribution of the volcanic rocks ; on the scale of 40 miles to
1 inch,

Discussion.
Dr. H. J. Jounston-Lavis and Mr. J. J. H. Tear spoke.

618 MR. E, GREENLY ON THE GEOLOGY oF THE [ Nov. 1896,

36. The Grotoey of the Eastern Corner of Anetzsry. By Epwarp
GreenLy, Esq., F.G.S. (Read June 10th, 1896.)

ConTENTS.

Page

Te Imitrod wetaonen tree ceencuces eet ebenes ce cedoeetone a teneenone ee 3 618

TE. “@areo*OnentSlaites* ce .cscs osccdecee rose Goserescescencdseneeeeeee eee 618

IT BarontEhlWor Bangor Group: .V.....001..+.c.she- scree oe eee 623
TV"Ordowictanisertes i.e. ke. kas ee vcs nnasene tiene ee ace eee 626 —

V. The Carboniferous Rocks (and Dykes)................csseeeeeess 628

WAP Giletatony ercec. cocae tscnessccenatiesesers:s.sceseaee cee nena eee 629

WALT SumanMany ce ntiececwscraeesc00s emaiececiec ove ous siabato+ceceRee eee aren eeRe 631

I. Inrropvuction.

THe observations recorded in this paper were made during a
detailed survey on the 6-inch scale, by myself, of a small portion
of Anglesey. It is my intention to continue the mapping of the
island on the same scale.

I should like to express my thanks to former workers upon
Anglesey, all those with whom I have come into communication
having expressed the warmest sympathy with my undertaking; and
in particular to my former chief, Sir Archibald Geikie, and to Prof.
Bonney, who have aided me very substantially by generous loans
of slides and specimens.’ My friend and late colleague, Mr. Peach,
has also, with his wonted goodness, looked over the graptolites and
other fossils forme. Dr. G. J. Hinde and Prof. T. Rupert Jones have
been so kind as to determine certain small organisms; and to
Mr. G. J. Williams I am indebted for the photograph of the slates
at Careg Onen.

II. Carzeg OneEn SLATEs.

The Carboniferous Limestone and Ordovician shales form the
greater part of the cliffs about the cove of Careg Onen ? (fig. 1), but
near the western end of the beach we find, emerging from beneath the
latter, a series of hard, greenish, fissile rocks dipping apparently at
very high angles (figs. 1, 2 & 3). Careful examination, however, re-
veals indistinct planes of bedding, crossing the conspicuous divisional
planes—which are really planes of cleavage—at various angles, and
evidently much folded (fig. 4, p. 620). There are some lines of dark
nodules following the bedding: some zones are gritty, and there are
others of hard, compact argillite, scarcely cleaved, which contain
a few oolitic grains.

1 T am preparing an Index of Anglesey Literature, which I hope to make
exhaustive. In these pages, therefore, passing reference only will be made to
the principal papers on the area.

2 Careg Onen is the name of the cove about 3 mile north-west of Bwrdd
Arthur. It has no name on any of the maps. This, and many other names
desirable for reference, will, I hope, be soon inserted in new editions of the

Ordnance maps.

_—

Vol. 52.] PASTERN CORNER OF ANGLESEY. 619

At the base is a peculiar grit, a few inches thick, composed
of quartz and detrital muscovite. Under the microscope certain
round bodies are seen in it, of which Dr. Hinde writes :—‘ The
rounded bodies in the slide are undoubtedly sections of sponge-
spicules, which are cut through some at right angles, others obliquely,
and very rarely in the direction of their length. The dark spot in
the centres of most of them is the axial canal of the spicule, now
filled with some dark mineral. In some cases the spicules have

Fig. 1.—Section at Careg Onen, Anglesey.
E.N.E. W.S.W.

——_—_

‘ eon
7 LEN ES
Cet ALS “y

ens
OLE L-

SF ZZ 4.
Red _Ked Ked
Shales Shales Shiles

[Horizontal and vertical scale : 1 inch = 440 feet. ]

a = Schists. e = Ordovician Shales.
h = Careg Onen Slates. d = Carboniferous Limestone.

[The bedding of ¢ should conform to their base-line throughout. |

Fig. 2.— Enlargement of x in fig. 1.
N.N.W. | 8.S.E.

| Mii, spoke Obscure
WG, Yep 3 LZ
We
fi } LIS Y pga ,

Grey shales with ironstone at base, overlying green schists

been squeezed out of shape. They are from ‘07 to -26 mm, in
thickness. I cannot say to what group of siliceous sponges they
may have belonged, for only these sections are to be seen. They
are now of microcrystalline (?) silica of the same character as is
usual with sponge-remains in Paleozoic rocks. They seem to be
fairly numerous in the rock,’ (See fig. 5, p. 620.)

The slate and argillite also contain micas, which often lie at
right angles to the cleavage, and are bent. The nodules show no
certain organic structures.

Q.J.G.S8, No, 208, 20

620

GEOLOGY OF THE EASTERN CORNER OF ANGLESEY.

[Nov. 1896.

Near the western end of the section the schists rise suddenly from
beneath these slates in a very sharp anticline (fig. 2), and disappear
again before rising en masse to the west, where there is a sharp fold

back, apparently torn
out into a reversed
fault thrusting the
schists a little over
from the west (fig. 3).

These slates are
certainly unconform-
able to the green
schists. Powerfully
as they are folded,
they are not in the
least affected by the
extreme and involved
contortions of the
schists, which are
clearly seen to be trun-
cated against their
base. Their micro-
scopic structures are
also entirely different.

Fig. 4.— Folded bedding wm pale green

slates ; fine gritty seams.
i J J 8.8.E.

——

Sees

[About 4 natural size. ]

Again, the slates themselves appear to be, not a lower part of
the Ordovician Series, but part of some older group separated from

Soe

Mate

agen

Oe ROP 5 *
7 ant
ov ni a

that series by another unconformity.

x 40,

Indeed, I think that this

junction, rather than that between the slates and schists, must be

Fie. 6.—Slates underlying Ordovician shales at Careg Onen, Anglesey.

Note.—The conspicuous divisional planes in the slates are cleavage, dipping
N.N.W. at 65°-85°. The bedding, which is much folded (see fig. 4, p. 620),
is not perceptible in this view. The Ordovician shales are seen at the top of
the cliff, dipping N.E. at 20°-30°.

622 MR. £, GREENLY ON THE GEOLOGY OF THE [ Nov. 1806,

the unconformity noted by Mr. Selwyn (Ramsay, ‘ Geology of North —
Wales,’ Geol. Surv. Mem. vol. iu. ed. 2, 1881, p. 223).

As seen from the beach (fig. 6, p. 621), the slates form a hard and
well-marked feature (in which the sharp anticline of schist is in-
cluded), over which pass the softer black shales, their bedding-planes
dipping at very nearly the same angle as the top of the feature.1_ The
discordance between their dip and the cleavage of the slates is most
marked, the latter being nearly vertical. The strikes also are in
different directions, the slates running E.N.E., and the shales at
this point N.W. Moreover, though it is difficult to trace bedding
for any distance in the slaty group, vet none of the beds, even when
at high angles, pass up into the group ahove, or over the crest of
the anticline, the schist rising nearly, if not quite, to the base of the
dark shales. Most important of all, the cleavage of the green
slates stops short at the base of the shales, which are quite un-
cleaved, even where seen, as at one place, actually in contact with
the lower group.” ,

Now these shales are not hard or coarse beds which would
resist a cleavage, but, it must be noted, are even finer and more
susceptible of such a structure than the lower rocks which possess
it in a high degree. Had the compression, therefore, operated at a
post-Ordovician date, these dark shales could not have escaped, but.
would have received a cleavage readily, as even much coarser beds
of that age have in the Caernarvonshire mountains.

The unconformity would seem, then, to be not merely local,
but of systematic value. But if we have here a fragment. of
an older system, that system could not be later than Cambrian ;
and indeed, as no break so pronounced has been observed in North
Wales between Ordovician and Cambrian, it would almost certainly
be older still. The occurrence, therefore, of undoubted organic.
remains in these rocks is of great interest, as they would appear to
be of pre-Cambrian age. Moreover, it would follow that the
group of crystalline schists here seen must be assigned, both as
regards their first formation and metamorphism, to a yet earlier
period.

Experience has shown, however, that it is unwise to build too
much upon the evidence of single sections, however decisive it may
appear, especially when the rocks have been subjected to powerful
earth-movements. There has been powerful movement here at
two, if not three, distinct periods. Confirmation from other
sections, or possibly from palzontological evidence, must therefore
be looked for.

But unless such evidence contradict that which is seen here, it
would seem that the crystalline schists of at least this region of
Anglesey must be of extreme antiquity. K

1 Vhe surface of the feature is marked by slickensides, which occur also
in the schists; but the discordance cannot be due to movement of this kind.
A false appearance of such movement has been produced in fig. 1 (p. 619)
hy my exaggerating somewhat the width of the anticline in the shales.

2 Mr. G. J. Williams, F.G.S., kindly permits me to add that he concurs
with me in this reading of the Careg Onen section,

Vol. 52.] EASTERN CORNER OF ANGLESEY. 623

III. Baron Hitt or Baneoor Grovr.

The stratigraphical importance of this group has been generally
admitted since the discovery of the classical section in the Baron
Hill drive by Prof. Bonney (Quart. Journ. Geol. Soc. vol. xxxix.
1883, p. 470): nor has any doubt been thrown upon his identification
of it with the volcanic group of Bangor. To his admirable petro-
logical description there is little or nothing to add.

The stratigraphical relations of the Baron Hill outlier have,
nevertheless, remained in some obscurity; and therefore certain
points which have come out in the course of the mapping will be of
some interest.

Prof. Bonney considered it probable that the junction was
faulted. Prof. Blake describes (Quart. Journ. Geol. Soc. vol. xliv.
1888, p. 463) a visible unconformity at the south-western end of the
drive section. The lowest rock seen there at present, however, is the
ashy grit; nor is anything else exposed in some bosses below the
drive at that point, which must be some feet lower down in the
series. Further, 1 would draw attention to the following points.

Prof. Bonney has remarked, with justice, upon the obscurity of
the dips in the drive. The cuttings were then fresh, and probably
the bedding has since become more distinct by weathering, though
it is still inconspicuous. On careful examination a fine, even
banding in the green argillites, with occasional sandy seams, can
be seen, dipping steadily a few degrees W. of N. at angles varying
from 30° to 90°, the average being high. Moreover, if any doubt
remained as to the drive section, there can be none as regards some
old weathered bosses along the top of the wood, where bedding with
the same dip and strike is perfectly clear. The thickness, measured
from these dips, would be not less than 1000 feet.

It will be seen that these planes strike almost directly at the
N.E.-S.W. boundary (as well as at the strike of the adjoining
schists); and if the structure be considered in relation to the form
of the surface, it becomes evident that the outlier cannot be resting
undisturbed upon the schists.

To explain this by normal faulting, however, would require very
large faults, of which there is no evidence whatever on the coast
to the 8.W.; and which, moreover, the mapping of certain zones
in the adjoining schists shows to be almost if wot quite impossible,
especially when the trend of the rock-features is considered. If
there be any such faulting, it must, I think, be of small throw, and
cannot extend all along the line. With regard to the E.S.E.—
W.N.W. boundary, it is probable that there is a normal fault; but
this must be a small one, as it does not appreciably displace a
zone in the schists south-east of Murddyn Siglen. The northern
boundary, however, is almost certainly a normal fault, running
W.S.W.; of which there is evidence also in the featuring—a deep
hollow in the hill-face, with a line of springs farther up.

It appears, therefore, that the Baron Hill outlier must be bounded
by and resting upon a plane of somewhat excey.tional natnre,

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’

Vol. 52.] GEOLOGY OF THE EASTERN CORNER OF ANGLESEY. 625

Unless the beds are rapidly folded in boat-shaped isoclines whose
axes are inclined nearly parallel to the slope of the surface, they
cannot be resting upon their natural base. This, however, is
unlikely from internal evidence. The sum of the evidence seems
to be in favour of supposing that they lie upon a dislocation-
surface inclined to the N.E. at an angle rather steeper than the
slope of the ground. ‘This would give the form of outcrop which
actually exists.

Turning now to the rocks seen in the drive, there is abundant
evidence that they have been subjected to movement such as might
be expected just above such a surface. They are, in fact, in the
same broken condition as are those masses of Cambrian and Torri-
donian sediments which in the North-western Highlands are brought
forward upon one of the major thrust-planes. The accompanying
sections (figs. 7 & 8), on the scale of 50 feet to 1 inch, illustrate this.
But they give no idea of the extent to which the fine argillites have
been fractured. This is shown in fig. 9, which is taken from a
spot 22 inches below the

thrust at the point X In Fig, 9.— Face of cliff, 22 inches below

fig. 7. Further, along the thrust shown at x, fig. 7.
this very thrust-plane

is a seam of material up
to ; inch thick, resem-
bling in every way the
mylonites of the High-
land thrust-planes. The
same phenomenon is seen
in several places. It
was difficult to obtain
material for slicing with- <
out defacing the surfaces Green banded argillite. Natural size.

(I hope that the section

‘x’ will be respected); and slices have therefore been cut from
specimens showing similar structure in the Tairfynnon Breccia near
Bangor, which it was surprising and interesting to find. These
show, under the microscope, perfectly typical mylonitic structures
(fig. 10, p. 626).

The direction of movement is manifestly from right to left in the
figures, but as these are not taken along the full dip, but along the
crag-faces, it is probably from north-east or east.

With regard to relative age, the contrast of metamorphic con-
dition between these rocks and the schists, on which stress is laid by
Prof. Bonney, remains, I think, unaltered; though perhaps caution
may be necessary in view of movements of the nature here described.
If, however, as certainly seems most probable, these rocks are later
than the adjoining schists, it is obvious that the overthrust sup-
posed must be thrusting higher beds upon lower, a reverse of the
usual effect. This, however, would follow if the angle of thrust
were less than the dip of the beds.

The evidence here given would lead us to expect that a zone of

626 MR. BE. GREENLY ON THE GEoLogy or THE [ Nov. 1896,

complicated structures, now concealed beneath the Carboniferous
Limestone, may underlie the old rocks of Bangor and Czernarvon.*

Fig. 10.—Mylonitic seam in Tairfynnon Breccia.

LV. OrpoviciaNn SERIES.

The rocks of this age which fall within the district under con-
sideration are almost entirely covered by Boulder Clay, and, towards
the northern end, nearly,’ though not quite, overlapped by the Car-
boniferous Limestone. ‘

The best section is that on the coast at Careg Onen, where about
700 feet of vlack shale, with a few red bands, are seen (fig. 1, p: 619%

These have yielded a shell like Obolella, and a fragment of a
trilobite (undetermined), as well as the fossils found by Prof.
Hughes (Proc. Camb. Phil. Soc. vol. iii. pt. vil. p. 347); and inland,
in some mudstones west of Bryn Poeth, I found some fragments
apperently of phyilopoda.

The occurrence of a bed of pisolitic ironstone is alluded to by
Ramsay (‘Geology of North Wales,’ p. 223). It does not occur at
Careg Onen,° but as, from evidence to be given below (see p. 628,

! Tam unable to confirm the occurrence of another outlier of this group
near Llanddona (Quart. Journ. Geol. Soe. vol. xliv. 1888, p. 465, and appended
map): the rocks belonging, in my opinion, to the schistose complex.

2 Their western boundary, which has been moved about 3 mile westward in
a recent map, was correctly drawn by the Geological Sueyey.

8 T do not think that the ironstone which there overlies the schists can be the
same. It has not the same character, is only 6 inches thick, and its associated
rocks are quite different.

Vol. 52.1 EASTERN CORNER OF ANGLESEY. 627

‘ Llanddona’), it is clearly not dying out in that direction, it is
probably cut out by the fault which throws down the Carboniferous
rocks, and if so, the beds with the trilobite and Obolel/a must be
below it. The obscure fossils hitherto found may quite well be
Arenig forms, and therefore only the upper part of the shale-series
can be upon any higher horizon.

An interesting point remains to be noted concerning the rocks
among which the pisolitic ironstone lies at Bryn Poeth (fig. 11).
These are not ordinary

grits and shales, but Fig. 11.— Bryn Poeth Quarry.
bedded felspar-tuffs of Section at the northern end.
varying texture, mixed w. . E.
with some sandy and) ~~~__..
muddy sediment. They Yee:

a m Fine Ge ar
are quiteuncleaved. The ium x" 22%
finer bands approach very stove

L
‘

nearly to shales, but the pis
coarser (fig. 12) are chiefly

composed of broken lath-shaped felspars, most of them quite angular,
and many even with re-entering angles, about ;/, inch in length.
They are often wonderfully fresh and beautifully twinned. The

A Fig. 12.—Felspar-tuff’ below pisolitic ironstone, Bryn Poeth.

matrix is dark, partly green by transmitted light, like that of the
pisolitic ironstone, and contains also angular fragments of dark
shale and andesitic lava, with generally a few pisolitic grains.

628 MR. E, GREENLY ON THE GEOLOGY oF THE _[ Nov. 1896,

The pisolitic ironstone itself also contains a tew lath-shaped
felspars. Though gradations exist, it does not pass imperceptibly
into the tuffs, but occurs in a well-defined bed about 18 feet thick.

The section is a little obscured by small faulting, but there appear
to be tuffs above and below. The whole series is about 50 feet
thick, and probably lies in a gentle synclinal fold.

It is clear, therefore, that we have here a record of a volcanic
episode contemporaneous with the latter part of the great Arenig
eruptions of Merionethshire. And it would seem to be due to a
separate outburst in this region, and not merely wind-borne from
the south, otherwise the pisolite and shale could hardly be so free
as they are from volcanic material.

(1 may add that, in the Didymograptus-beds at Caernarvon, 1
found beds of very similar tuff, lying as hard ribs among the dark
shales at Pont Seiont. I have failed to find any, however, in the
shore-section east of Port Penrhyn at Bangor.)

There is no perceptible cleavage, but there has been powerful
earth-movement, the shales at Careg Onen folding over, and
plunging against the schists of the western end of the section.

Llanddona.—A. tract of Ordovician shales must exist, almost
entirely concealed by Boulder Clay, skirting the coast for about
4 mile on either side of Llanddona Church, and extending about
3 mile inland. :

While mapping the drift-covered slopes I observed a great number
of blocks of black mudstone, along with which were also many of
pisolitic ironstone, and the drift itself was full of small angular
fragments of black shale. At last two small exposures of shale,
like that of Careg Onen, were found at Corn-ud. ‘They dip W.S.W.
at 25°, and are probably faulted against the schists.

I think it is safe to assume that this area is occupied by such
shales (its featuring, moreover, is quite unlike that of the schists),
and have therefore inserted it on the maps.

One or two of the boulders have yielded graptolites—‘ Climaco-
graptus, of a type that occurs in the Llandeilo-Caradoc rocks,’
Mr. Peach writes, adding that he ‘should think they belong to
CO. bicornis, but, without seeing their proximal ends, would not like
to say anything further.’

V. Tue CarsponiFerous Rocks.

These rocks are noticed briefly in Ramsay’s ‘Geology of North
Wales,’ pp. 258-59. They present some points of general interest.

The prevailing type is a light grey, rather crystalline limestone ;
but there are many interesting varieties, particularly a thick mass
of brown dolomite with pyrites and other heavy minerals,

Most striking, however, are the sandstones and conglomerates
which occur near the Hast Point, and at Seiriol and Fedw Fawr,
near the middle of the area. They are about 90 or 100 feet thick,
and consist chiefly of very fine white sandstone, with pyrites and
carbonaceous particles, and partings of soft grey shale. Obscure

Vol. 52.] EASTERN CORNER OF ANGLESEY. 629

plant-remains abound. At their base is a strong conglomerate about
20 feet thick, composed of vein-quartz pebbles with many of red
jasper and green schist, as well as of limestone with Carboniferous
fossils. Another conglomerate, less persistent, occurs higher up in
the group. So far as faulting, which near the East Point is very
frequent, permits one to judge, these groups of Seiriol and Trwyn-du
appear to be on the same horizon (a thin conglomerate near Llangoed
is much lower down); though perhaps not accurately so, as in
certain sections pebbles and sand can be seen to come in on the
same horizon as pure limestone.

Dark shales occur at all horizons, but are generally very thin.
One of the thickest (about 6 feet) contains some small ostracoda.
Prof. T. Rupert Jones refers them, doubtfully, to a small ovate form,
probably Leperditia acuta, adding, however, that if a feature sug-
gestive of a ventral rim or margin be really such, he would be
unable at present to determine the specimens definitely.

The thickness of the whole series appears to be about 700 feet.
‘ Brecciation’ is not uncommon in some of the limestones, quite
unconnected with faulting, and appears to be really an early stage
of dolomitization, the change proceeding along the cracks.

The unconformable relation to the underlying Ordovician Shales is
well seen at Careg Onen (fig. 1, p.619). The lowest beds seen—about
20 feet from the base—are dark limestone with shaly partings, and
there is no sign of a conglomerate.

Dykes.—Three dykes mapped in the Baron Hill Rocks show a
matrix exactly resembling, under the hand-lens, that of the andesitic
dykes described by Mr. Harker (Geol. Mag. 1887, p. 409), with which
also they agree in trend and general relations. There is no reason
to separate them from that group, arguments for whose Carboniferous
or post-Carboniferous age have been given by previous writers. A
good many have heen already mapped in the schists to the west, but
their relations—which are interesting—will not be dwelt on in this
paper. The dyke noted by Prof. Bonney (I trust, with him, that
the ice-worn surfaces will be scrupulously respected) is quite thin,
about 2 feet wide. The optical characters of its porphyritic crystals
indicate a felspar allied to labradorite. There is also a dyke, about
12 feet wide, cutting the lowest boss of ashy grit in the drive.

VI. Guacrarion.
(a) Striation.

Striz are rare, except on the Carboniferous coast-line where the
drift has been but recently removed.

The prevailing direction is 8.8.W., or a few degrees W. of S.,
except in a district lying east of a line drawn from Dinmor Point to
Trwyn Penrhyn, in which there is cross-hatching with a series
running 8.S.E. Where they can be compared, the 8.S8.W. series
can be seen to be the later.

630 MR. E, GREENLY ON THE GEOLOGY OF THE _ [ Nov. 1896,

Local deflections throngh as much as 40° may be observed on
rock-faces no more than 3 feet high.

There are large glacial furrows in a few places.

Rock-bosses are generally moutonnés, on the N.N.E. side.

(b) Drifts.

The drift is for the most part a typical, tough, brown Boulder
Clay, full of well-striated stones.

It is very thick in the Vale of Llanfaes, probably not far from

100 feet, fine sections being seen on the coast between Penmon and
Beaumaris (Ramsay, op. cet. pp. 275-76). There is none on the
Carboniferous escarpment, but it thickens gradually on the dip-
slope, where there is one valley buried to a depth of 60 feet. The
brow formed by the schists is also free from drift, which, however,
again begins to fill hollows in the plateau to the westward.
_ A great tbickness of Boulder Clay comes in again near Llanddona
Church, where it forms cliffs about 50 feet high. Below Ffynnon-oer
this Boulder Clay suddenly rises to the 200-foot contour, forming an
inland cliff which must nearly follow a concealed rock-feature.
There has been much land-slipping here, probably upon buried
Ordovician shales.

Such boulders as can be identified with local rocks have travelled
S.W.-S.S.W., a direction agreeing with that of the striz. Boulders
from the Welsh mountains have only been observed at Penmon ; but
rocks foreign to North Wales are abundant.

The gravels associated with the drift along the Lleiniog shore have
been described by Ramsay, who notes their semi-consolidated state.
They contain faintly-striated stones. Similar gravels occur at
Llanddona. .

About Llanfaes there is a singular stoneless (or nearly. stoneless)
red clay, as much as 10 feet thick. Its relations are not exposed.

These phenomena seem to me to be best explained by the theory
of a confluence of bodies of glacier-ice coming from the north and
from the Caernarvonshire mountains respectively. Not only does
it explain the general south-westerly deflection of the striae and
boulders, but I think that the cross-hatching in the Penmon area can
also be understood by means of it. In that area complications must
have occurred, ‘The influence of the great Ogwen glacier must have
been much less than it was farther west, and the glaciers of Aber
and Llanfairfechan only would have opposed the northern ice. On
comparing the extent and height of their catchment-basins I doubt
whether their combined force would amount to more than a quarter
of that of the Ogwen glacier. That they did offer opposition is
clear, for they extended at times as far as Penmon. But fluctua-
tion in the masses of the northern and southern streams would
enable the larger stream to pass on undeflected, especially if some
fluctuations did not affect both at once, which might well happen—
as their sources were so far apart. The local influence of some high
ground at Dinmor Point (west of which, moreover, there is an

Vol. 52.] BASTERN CORNER OF ANGLESEY. 631

extreme deflection to W.S.W.) would then come into play, and cause
the S.8.E. deflection. Moreover, the Llanfairfechan glacier, being
the feeblest, would be the first withdrawn, and the Aber glacier
would then rather aid the 8.8.E. deflection than otherwise.

VII. Summary.

_ The south-eastern promontory of Anglesey consists chiefly (besides
the schists) of Ordovician and Carboniferous rocks, overlain by
extensive Glacial deposits; but there are also two small but im-
portant fragments of ancient formations at Careg Onen and Baron
Hill.

The slates of Careg Onen rest unconformably upon the schists,
and appear to be separated by another strong unconformity from
the Ordovician shales. Whence it would appear, pending con-
firmation from other sections or direct fossil evidence, that the
slates (which contain sponge-spicules) must be of pre-Cambrian
age, and the schists themselves even older.

The ashy grits and bedded tuffs of Baron Hill appear to have
been moved somewhat from the N.E. along a plane of overthrust.
They are traversed by planes of mylonization, as well as isoclinally
folded, and in general much broken up.

The Ordovician rocks consist chiefly of dark shales and mudstones,
sparingly fossiliferous, but contain a group of volcanic tuffs on the
horizon of the pisolitic ironstone. Another tract of Arenig beds,
with the pisolitic ironstone and graptolitic shales, lies concealed
beneath glacial drift at Llanddena.

The Carboniferous rocks appear to be about 700 feet thick. They
contain 100 feet of conglomerates, sandstones, and shales, with
plant-remains, about the middle of the series.

The glacial strize sweep round from 8.S8.W. at the northern to S.W.
and W.S.W. at the southern end of the district. In the Penmon
area there is cross-hatching with a series running 8.8.E., and it is
suggested that this is due to fluctuation in the power of the Caer-
narvonshire glaciers to deflect the ice coming from the north,
combined with the local influence of certain high ground.

Discussion.

Sir ArcurBaLp Gerxin rose, not for the purpose of criticism, but
to congratulate the Society on the acquisition of a geological recruit
who, possessing leisure, enthusiasm, and capacity, was likely to
advance the progress of geology in this country. Notwithstanding
all that had been written regarding the geology of Anglesey, the
subject still bristled with difficulties. Unsolved problems presented
themselves in every part of the island. ‘These could never be settled
by mere hurried holiday visits, but needed such patient investigation
as was demanded in the preparation of a geological map of the
district on a large scale. The present paper, and the little piece of

632 GEOLOGY OF THE EASTERN CORNER OF ANGLESEY. _[ Nov. 1896,

mapping which accompanied it, were no doubt an earnest of what
might be expected from the Author, who would carry into his
labour the habits of minute and accurate observation which had
distinguished his field-work when he was a member of the staff of
the Geological Survey.

The Prusipent said that he was pleased to find that Mr. Greenly
had undertaken to work .out, with so much care, the geology of
Anglesey. There were many important points in connexion with —
the crystalline schists and the overlying rocks which needed eluci-
dation ; but he was glad to find that the Author agreed with the
speaker and others that the crystalline schists were of pre-Cambrian
age and overlain unconformably by the Paleozoic rocks.

Prof. G. A. J. Corn congratulated the Author on picking up the
history of Welsh vulcanicity in Anglesey, and on the discovery of a
voleanic deposit on the horizon of the pisolitic ironstone, in addition
to the more conspicuous and better-known areas of Cader Idris and
Rhobell-fawr. He also compared the conglomerates containing
blocks of the contemporaneous Carboniferous beds with those on the
opposite Irish coast north of Rush, which occur along the junction
of the Carboniferous Limestone and the old Ordovician shore.

The AvutHor expressed his thanks to the Society for the manner
in which the paper had been received.

a

z=

Vol. 52.] | FOLIATED GRANITES IN EASTERN SUTHERLAND. 633

37. On FortareD Granites and their Retations to the CRYSTALLINE
Scuists in HasterN SutHERLAND. By J. Horne, Esq., F.R.S.E.,
F.G.S., of H.M. Geological Survey of Scotland, and E. Greenty,
Ksq., F.G.S., formerly of H.M. Geological Survey. (Communi-
cated by permission of the Director-General of H.M. Geological
Survey. Read June 10th, 1896.)

ConTENTSs.
Page
LOTS UL (0) Oe Se Penns Mane eh 633
Mi Mirkbomiy FO ATIMAG ALE a. 622 een tnp dels ccciawabvaceoncssenens 636
E01. Portskerry to. Armadale (sic... 0.22 ccieocere se: fe hed Sina 639
iV, Kanbrace.and Kildonan) Area )....d. sc. ci cdexieueessess cess 642
Niereunimary and Conclusions. acid: sci veeve soc ioecesewen ae 645

I. Iyrropvuctrion.

Tur detailed mapping of the eastern portion of the County of
Sutherland by the Geological Survey has shown that the crystalline
schists of that region are extensively penetrated by granites, more or
less foliated, which are apparently linked to some extent with the
present crystalline characters of these schists. Some of the features
presented by these foliated granites have already been described
by previous observers.

In 1862 Prof. Harkness remarked that the mode of occurrence of
the granites in the east of Sutherland rather tends to the conclusion
that the sedimentary rocks were elevated, flexured, and contorted
previous to the period when the granites made their appearance in
the sedimentary rocks, and that these granites have conformed in
their course to the strike of the previously elevated strata. He
further observes that here are abundant features which would
support the conclusion that granite is in this district rather the
result of an excessive amount of metamorphic action than a plutonic
rock as regards its origin.’

in 1869 the Rev. Dr. Joass stated that he was inclined to regard
the granites in the Kildonan region as partly intrusive and partly
metamorphic. He further noted that in the most richly auriferous
localities certain granitoid rocks, chiefly felspathic, are so intimately
connected by interlamination with the flaggy quartzose strata that
they almost appear to be the result of metamorphic action upon
true sedimentary rocks of the quartzose series, or contemporaneous
effusions of plutonic rock. This granitiform rock appears at least
in one instance to run across the strike of the decomposed gneissose
strata.”

1 «On the Metamorphic Rocks of the Banffshire Coast, the Scarabins, and
a Portion of East Sutherland,’ Quart. Journ, Geol. Soc. vol. xviii. p. 331.

2 “Notes on the Sutherland Goldfield,’ Quart. Journ. Geol. Soc. vol. xxv.
p- 317.

634 MESSRS. J. HORNE AND FE. GREENLY ON [ Nov. 1896,

The minute penetration of gneiss, schists and sedimentary deposits
altered by contact-metamorphism, by granitic materials in the form
of excessively thin folia along the planes of schistosity was first
clearly described by Michel-Lévy. In his paper ‘ Sur POrigine des
Terrains Cristallins Primitits’ he makes the following observations :
‘J'ai, le premier, appelé l’attention sur le phénomeéne de pénétration
intime, lit par lit, des roches granitiques et granulitiques éruptives
suivant les plans de schistosité des gneiss et des schistes ... Mais en
outre, dans les zones de contact immédiat sur la roche éruptive, le
quartz ct les feldspaths s’insinuent, lit par lit, entre les feuillets des
schistes micacés ; on est parti d’un schiste argileux détritique, on le
trouve en definitive transformé en un gneiss récent, bien difficile
i distinguer des gneiss anciens.’*

In 1890 Miss Gardiner described some of the contact-phenomena
produced by the granite near New Galloway, and showed how the
Silurian sediments pass into crystalline schists and gneiss with
various contact-minerals at the granite-junction.*

In the same year, while referring to the gneisses of central
Aberdeenshire, our colleague Mr. Hinxman states that the granitoid
character of the gneiss at certain points is due to the intrusion of
granitic material along the planes of foliation.®

In 1898 our colleague Mr. Barrow described in detail the meta-
morphism produced by an intrusion of muscovite-biotite-gneiss in
the South-eastern Highlands. He showed that the normal con-
dition of the intrusive rock is that of a slightly foliated granite with
two micas, but with considerable variation as regards structure and
composition, the larger masses being more or less fringed with
pegmatite. The foliation of the larger masses is rudely parallel to
that of the surrounding schists, and though their intrusive nature
is therefore not so obvious, it has been proved by detailed mapping
that these masses traverse different bands of the schists. The
crystalline gneisses and schists with the contact-minerals, sillimanite,
cyanite, and staurolite, arranged in zones according to the stages of
metamorphism, are held to be due to the intrusion of muscovite-
biotite-gneiss.*

In 1890 the Geological Survey first broke ground in the east of
Sutherland from Melvich as a centre: the coast-line between Strath
Halladale and Armadale having been assigned to Mr. Greenly. On
the shore at Portskerry he observed minute granitoid fclia radiating
from the larger granite masses and traversing the granite-like
schists. Mr. B. N. Peach mapped the larger sills of acid igneous rock
in Strath Halladale and clearly recognized their intrusive character,
ascribing the foliation of the granite to dynamic action. In the

' Bull. Soc. Géol. France, ser. 3, vol. xvi. (1888) pp. 104, 107.

2 *Contact-Alteration near New Galloway,’ Quart. Journ. Geol. Soe.
vol. xlvi. p. 569. 5

3 Geol. Surv. Scotl. Explanation of Sheet 76, p. 12.

+ «Onan Intrusion of Muscovite-biotite-gneiss in the South-eastern
Highlands of Scotland and its Accompanying Metamorphism,’ Quart. Journ.
Geol, Soc. vol. xx. p. 330,

s

a

‘
Vol. 52.] FOLIATED GRANITES IN EASTERN SUTHERLAND. 635

same year (1890) Mr. Horne obtained confirmatory evidence of the
‘lit par lit’ introduction of granitic materials into the crystalline
schists south-west of Strath Halladale. In the autumn of 1891 and
1892 Mr. Horne surveyed the coast-section between Kirktomy and
Armadale and the tract extending south-eastward towards the
Armadale burn, where there is a group of complex gneisses formed
by alternating folia of granitoid materials and granulitic or coarsely
granulitic gneisses or schists, recalling some of the Lewisian types
between Cape Wrath and Laxford. These phenomena, which seem
to have been developed at a later date than granulitic schists of the
‘Moine’ type, were briefly summarized in the Annual Report of
the Geological Survey for 1892.

From the northern coast of Sutherland these intrusive granite-
masses and pegmatites have been traced across the county by
Forsinard, Kinbrace, and Kildonan to the Ord, Helmsdale, and Upper
Strath Brora: Mr. Greenly having mapped the Kinbrace and
Kildonan area, and our late colleague, Mr. Hugh Miller, the tract
between the Ord and Upper Strath Brora. During 1893-94 Mr. Hugh
Miller observed the phenomena resulting from the minute penetra-
tion of the eastern schists by granite on an extensive scale in the
outlying parts of Rogart and Clyne. His observations in Upper
Strath Brora led him to the following conclusions. The structures
in the granites and granitic gneisses were supposed by him to be
‘to a large extent imitation-structures, due to a simulation of the
form and structural features of the country rock (the eastern
schist) by granites that have by some means crept into their place.
The process by which this replacement has been effected seems to
have been a development of crystalline matter among the granulitic
materials of the pre-existing schists and quartzites. In the earlier
stages of metamorphism the granitic substance has entered or by
some means suffused the structure of the stone, appearing first as a
fine mottling of granitic particles. In further stages of meta-
morphism the granitic matter, keeping for the most part to the folia
of the pre-existing rock, has increased into knots and knotty
strings, has entered planes, slide-planes, and the lines of contortion
in the contorted schists, and so thickens into bands and sills at the
expense of the original rock, till the latter is represented only by
inclusion-planes and ultimately by inclusion-structures. The
crystalline matter of the granitic gneisses and granites remains
optically complete, and the inclusion-structures and the inclusion-
planes everywhere retain the same dip and strike as that of the
country rock, not only in Upper Strath Brora, but also in Rogart and
wherever present in the granite massifs of Helmsdale and the Ord
of Caithness. Parts of these granites are in fact pseudomorphs or
granite-casts preserving as replacement-structures remains of the
structure of the pre-existing rock.’

Q.J.G.8. No. 208. 2x

636 MESSRS. J. HORNE AND £. GREENLY ON [Nov. 1896,

Il. Krrxtomy to ARMADALE.

The various types of crystalline schists with which the granitic
rocks are associated in this area may be grouped as follows :—

1. Granulitic schists or gneiss.

2. Biotite-schists and gneiss.

3. Granular gneiss.

4, Hornblende-gneiss or schist.

5. Cipolin group (crystalline limestones containing silicates).

The members of the first two groups display in a remarkable
degree the introduction of granitic materials in the form of granitoid
folia; thus giving rise to a series of complex gneisses, composed
partly of granulitic and partly of granitic constituents. The
evidence in the area between Kirktomy and Armadale seems to
point to the conclusion that these constructive processes operated
after the formation of certain granulitic schists allied to the type
of the ‘Moine’ schists, and yet the series of complex gneisses
recalls some of the features of the Lewisian gneiss between Cape
Wrath and Laxford.

The granite occurs in the form of branching sills, veins, and
minute folia, penetrating the schists and gneiss along the planes of
foliation, and in places it merges into massive pegmatite. It is
usually foliated, the foliation being parallel to that of the schists,
though in some instances it is clearly transgressive.

The essential constituents of the granitoid rocks are orthoclase,
oligoclase, quartz, and biotite. A specimen of gneissose granite,
taken from the shore at the edge of the outlier of Old Red Sand-
stone, 3 mile north of Kirktomy, shows under the microscope
orthoclase, oligoclase, quartz, and biotite, with apatite and zircon as
accessories.. Both felspars occur as allotriomorphic grains, but
there are occasional signs that oligoclase may be idiomorphic with
respect to an untwinned felspar which is presumably orthoclase.
Here and there indications of a micropegmatitic intergrowth of
quartz and felspar may be observed. The biotite does not occur as
a rule in the form of detached plates, but usually in aggregates of
several individuals which mutually interfere with each other. In
a specimen of granitoid gneiss between Kirktomy Point and Geodh na
Muice muscovite occurs, though not in any great abundance,
together with biotite, orthoclase, oligoclase, and quartz. These
foliated granites and granitic gneisses are well displayed in the
massive form between Kirktomy Point and Pollsain, about 4 mile
east of the headland.

The granitoid folia, alternating with folia of granulitic schists
and biotite-gneiss, may be studied near Kirktomy Point and about
a mile to the east near Poulouriscaig. Their constituents resemble
those of the larger veins and sills, with the exception that biotite

1 Microscopic sections of rocks from the Kirktomy area have been examined

by Mr. J. J. H. Teall, M.A., F.R.S., who supplied notes on the various rock-
specimens and sections.

J

"Vol. 52.] | FOLIATED GRANITES IN BASTERN SUTHERLAND. 637

is sparingly developed. They contain orthoclase, oligoclase, quartz,
and occasionally biotite. Indeed, the remarkable feature of the
granitoid rocks as a whole, both in the case of the larger masses
and in the granitoid folia, is the abundance of oligoclase. A
specimen taken from a locality about 100 yards from the edge of the
eliff §.S.E. of Kirktomy Point, in which the granite-bands can
be seen cutting across the folia of the darker granulitic rock,
shows under the microscope that the granitic bands consist of
quartz, oligoclase, and orthoclase, with garnet and apatite as
accessories. So minute are these layers of granitic materials that
in some instances they do not exceed j inch in breadth: and hence
in a specimen, say a foot across, there may be several granitoid
bands alternating with layers rich in biotite or with granulitic bands
containing quartz, felspar, and mica. It is further observable that
the granitoid folia follow the various folds, and even the minute
puckerings of the biotite-gneiss and the granulitic gneiss, without
any apparent crushing or deformation of the constituents. The size
of the grains does not vary with reference to the margin of the band,
and there is no trace of chilled margins. Still more noteworthy is
‘the fact that along the junction-line separating the granitoid from
the other folia the minerals interlock just as they do in the interior
of the different folia.

It is obvious that these phenomena do not resemble those of an
igneous rock penetrating pre-existing strata along cracks and
fissures where chilled margins may be readily detected. Indeed, an
unbiased observer would almost infer at first sight that the
granitoid bands are not in reality later than the gneisses and schists
which they traverse. But in many excellent sections the quartzo-
felspathic folia, which are identical in structure and composition
with the quartzo-felspathic portions of the larger granite-masses,
an be seen branching from the latter and following the contorted
foliation-planes of the pre-existing strata. It seems reasonable to
infer, therefore, that these igneous materials were introduced when
earth-movements were in progress and when the pre-existing rocks
were at a high temperature.

Throughout the area, numerous lenticles of granulitic schist: occur
as isolated masses in the foliated granite, the foliation of the schist
being parallel to that of the granite. An excellent example is met
with on the shore south of Uamh Dhom near Pollsain, east of
Kirktomy Point. Here small lenticles of highly siliceous schist of
the ‘ Moine’ type occur, with the planes of schistosity parallel to
that of the granite. This instance further shows minute granitoid
folia branching from the main mass and traversing the foliation-
planes of the inclusions of granulitic gneiss. Under the microscope
this siliceous schist or gneiss is composed of quartz, felspar, and
biotite, with garnet as an accessory. Some of the quartz occurs as
irregular patches.

In the belt of garnetiferous biotite-schist or gneiss extending
southward from Kirktomy Bay to Creag Meadie, foliated granite
and pegmatite occur as lenticular masses varying from a few feet

2x 2

638 MESSRS. J. HORNE AND HE. GREENLY oN [ Noy. 1896,

to several yards or more in length. Their constituents resemble
those of the larger veins and sills already described. Immediately
to the west Mr. Peach has traced a great series of thin sills of
foliated granite traversing the biotite-schist and granulitic gneiss.

Where the granitoid rocks traverse the biotite-schist or gneiss on
the moor about 2 miles south of Armadale, the contact-mineral
sillimanite was observed in the latter, associated with the biotite
This mineral was likewise found in an inclusion of biotite-gneiss
in a granite-vein. The occurrence of the quartz in the biotite-
gneisses in large, almost ophitic patches may also point to contact-
metamorphism—if we may judge from an instance of the change
produced in siliceous gneiss at the point of contact with an intrusive
mass of augite-biotite-diorite at Sandside, Reay, in Caithness.

The foliated granite and the complex of gneisses between Kirk-
tomy and Armadale are traversed by veins of pink microgranite,
which, so far as observation goes, are never foliated. These veins
probably represent the last phase of igneous activity, which culmi-
nated in the introduction of the broad sills of foliated granite.

Reference may now be made to some of the other groups of
crystalline schists represented in the area under consideration.

Group 4, composed of hornblende-gneiss or schist, is likewise
traversed by gneissoid granite and pegmatite. It occurs in lenti-
cular bands or masses, which are represented on the eastern side
of Kirktomy Bay, and on the moor to the south-east. A specimen
from the eastern cliff of Geodh Acrah, 3 mile north of Kirktomy,
examined under the microscope by Mr. Teall, shows felspar, mostly
striated, quartz, and green hornblende, with biotite and sphene as
accessories. The three principal constituents occur for the most
part as allotriomorphic grains. Now and then the quartz appears
to form inclusions in the felspar and hornblende. The micro-
structure is granitic, not granulitic. Mr. Teall adds that there
is no doubt a close resemblance between this rock and basic portions
of the Lewisian Gneiss occurring between Laxford and Cape
Wrath. Sera I

The granular gneiss (group 3), which extends from Armadale
Bay westward for a distance of 2 mile, is a rather fine-grained
granular rock, containing quartz, felspar (including oligoclase),.
biotite, and sometimes hornblende. This group is associated with
highly quartzose schists or gneiss, with magnetite in well-formed
octahedra.

The Cipolin group (no. 5) is in some respects the most interesting
of this series. The rocks included in this group are exposed in a
burn draining into the sea, about 2 mile W.N.W. of the village
of Armadale. In the lower part of its course, where it flows
through a rocky gorge, a band of crystalline limestone is exposed at
the base of the cliff. One specimen from this locality has been
named by Mr. Teall a banded cipolin, one band being mainly com-
posed of crystalline calcite. Under the microscope it shows scapolite,
calcite, quartz, a pale green pyroxene, and sphene. Scapolite is the
most abundant mineral in that portion of the rock from which the

-

Vol. 52.] FOLIATED GRANITES IN EASTERN SUTHERLAND. 639

section is taken. The principal constituents occur in allotriomorphic
grains.
. The crystalline limestone is associated with a green crystalline
granular rock, composed mainly of allotriomorphic grains of pale
green pyroxene (omphacite), with altered scapolite, sphene, and
pyrite. Along the strike of these rocks, on the sea-cliff at the
mouth of the stream, flaggy hornblende-schist with omphacite is
exposed; and in the walls of the gorge flaggy biotite-gneiss occurs
with felspar (including oligoclase), quartz, and biotite. Apatite,
zircon, and garnet appear as accessories. The foregoing series is
pierced by veins of pink microgranite and pegmatite.

While in the foregoing pages we have adduced evidence suggesting
a close relation between the granitoid folia of the complex gneisses
and the foliated granites, it ought to be frankly admitted that there
is a striking resemblance between the mineralogical constituents of
the granulitic biotite-gneiss and the granitic gneiss,

III. PorrskerrRy To ARMADALE,

The crystalline schists into which, in this region, the granitoid
rocks have been introduced are of three types :—

1. Granulitic, seen on the coast from Portskerry to Baligal.

2. Wavy biotite-gneiss. On the coast this is concealed by the
Old Red Sandstone of Baligal; but it is well exposed on the
hills about Beinn Ruadh and Bowside.

3. Granular gneiss of Strathy Point.

The granulitic type is an ordinary fine-grained flaggy schist,
composed of quartz, felspar, and biotite, arranged in a mosaic.
No traces of clastic structure can be seen, but the rock is very
quartzose.

The second type is a highly crystalline gneiss composed of felspar
{chiefly oligoclase), quartz, and large wavy flakes of very black
mica. It will be described in more detail in the section devoted to
the Kinbrace area.

The ‘granular’ gneiss is an even, medium-grained rock, also
composed of striated felspar, quartz, and biotite; but of an excep-
tional crystalline type, allied to the granulitic, the constituents,
however, being on a scale too large for it to be described by that
name. Seams of both the other types occur in it, and also peculiar
quartzose schists rich in idiomorphic magnetite.

The granitoid rocks are composed of quartz, felspar, and biotite.
The felspar is chiefly oligoclase, but those in the eastern part of the
area (Portskerry) contain also porphyritic orthoclase.

Basie rocks (amphibolites and hornblende-schists) also occur.
Their relations are not perfectly clear, but need not be dealt with
in this paper.

In all the schists the granites occur as anastomosing lenticular
sills. They are exceedingly numerous, even those large enough to

640 MESSRS. J. HORNE AND E. GREENLY ON [ Nov. 1896,

be mapped occupying about one-third of the surface in the well-
exposed parts, while the smaller outcrops are innumerable.

The relations to the various types of schists are slightly different.
The grauites and the granulitic rocks, however intimately inter-—
banded, are sharply distinguished from each other. The cliffs of
Portskerry display a strongly banded series (fig. 1), composed of rapid:

Fig. 1.—Gneisso-granitic complex, Rudha Ghoiridh, Portskerry.

A = Gneiss. B = Granite.

The granite is slightly foliated.

alternations of grey granulitic schist and pink granite, with here and
there lenticular sills of foliated porphyritic granite from 2 to 3 yards
thick. The thin bands are true veins, for though at first sight con-
formable with the gneiss, they can be proved to truncate its folia.
and to anastomose. Of their connexion with the granites there
can be no doubt, for the whole series is traversed by precisely similar
veins at right angles, which can be seen to be continuous with some
of the bands, while cutting others. These veins usually le along
planes of dislocation which fault many of the granite-bands, but
these old faults are completely ‘ healed up,’ the crystals interlocking
along them, and there being no sign of cataclastic structure.
With regard to foliation :

1. The granite is almost always foliated, the structure being
marked out, not only by the orientation of the mica-flakes,
but by that of the porphyritic felspars. Sometimes there
are felspar ‘augen,’ and even bands, the whole mass being
there very complex. But generally the felspars are angular,
and even zonal.

2. The foliation usually follows the cheeks of the sill or vein.
Sometimes it is discordant to that of the schist ; sometimes-
it folds rapidly, without the sill folding as a whole; and again
here and there, though rarely, a foliation parallel to that of
the schist appears to pass through a vein. Finally, in the

Vol. 52.] | FOLIATED GRANITES IN EASTERN SUTHERLAND, 641

ends of a sill are sometimes seams of biotite whose flakes
have the peculiar oblique orientation which they possess in
the gneiss.

There are no chilled edges; the margins, indeed, are often fringed
with pegmatite ; while the thinnest seams are wholly pegmatite.

In the granular gneiss of Strathy Point, the relations of the
granite are more intimate. The granites differ slightly in character,
as well, porphyritic felspars not being developed. There is an
absence of the parallel interbanding that is so marked at Portskerry,
the small sills being lenticular, like the large ones. The sills are
extremely irregular in form; they sometimes run right across the
gneissic folia for 20 or 30 feet, inosculating, however, along the edges.
In and near the basic rocks of Armadale Bay there is an amazing
development of highly complex veining, though sills are also common.
But most important are the apparent passages between gneiss and
granite. Sometimes a sill will have distinct transgressive junctions
on one side, while on the other it is difficult to decide where the
boundary shall be drawn.

The behaviour of the granular gneiss is singular. Throughout
the Point the coarse granitoid rock cuts it; and yet here and there
it appears itself to give off veins, and cut granulitic and basic rocks.
Indeed, this ‘granular’ gneiss is the most perplexing of all the
types. Very likely it includes rocks of various nature and origin.

Fig. 2.—Part of base of great sill, Strathy Bay.

A = Gneiss. B = Granite.
There is a faint foliation in the granite, rudely parallel to that of the gneiss,

On the cliffs of Glas Eilean and Boursa Cove, magnificent sections,
250 feet high, expose the internal structure of the great sills. They
are highly complex synthetic gneisses, consisting of foliated granite,

642 MESSRS, J. HORNE AND E. GREENLY oN ___[ Nov. 1896,

full of inclusions of all sizes, up to 100 feet long, round and between
which the granite passes in gently undulating curves, retaining its
own independent foliation, which often truncates that of the
inclusions,

In Strathy Bay sills of very massive grey rock, with clear fresh
oligoclase and a beautiful waxy lustre, are seen. The junctions are
perfectly exposed, showing forms intermediate between sills and
dykes (fig. 2, p. 641). Within this mass granites indistinguishable
in hand-specimens can be seen to vein each other, both rocks being
independently foliated.

Both at Strathy and Portskerry, the whole foliated series is
traversed by dykes of pink microgranite. They are unfoliated,
and, though compact, have no chilled edges. They cut all the other
rocks very sharply.

LV. Kinprace AND Kiznponan AREA.

Although the exposures in this district are far less complete than
those on the northern coast, they have especial interest, because the
less altered condition of the rocks at Kildonan allows us to see that
some, at any rate, of the crystalline schists into which the granites
have been introduced must be of sedimentary origin.

The following groups or types can be distinguished :—

1. Quartz-schist.

2. Granulitic biotite-schist.

3. Wavy mica-schist.

All these are truly crystalline schists, composed of interlocking
minerals; the structure of Nos. 1 and 2 being that of a granulitic
mosaic.

There can, however, be no doubt that No. 1, at any rate, is a
highly altered quartz-felspar grit. Not only are clastic grains
clearly recognizable in certain parts, but the highly quartzose
character, maintained over a large area, makes its sedimentary origin
practically certain. There arealways some felspar and white mica,
and seams of iron ores are a characteristic feature.

Group 2 resembles the granulitic schist of Portskerry, differing
only in that a few bands contain muscovite as well as biotite. But
its relations to the quartz-schist throw light on its origin. Not only
do seams of Group 2 occur constantly within the main mass of
Group 1, but the main masses of each always pass one into another
through a series of alternations in such a way as to leave little
doubt of their common origin. The boundaries on the map are,
indeed, quite arbitrary, and it is often difficult to decide how to
colour the intermediate types.

Group 3 is different in texture. It is a very wavily foliated
schist, composed of both micas, quartz, and felspar (sometimes cer-
tainly oligoclase). The micas are much larger than in the granulitic
rocks, and the biotite is a deep brown ferruginous variety. Garnet
and sillimanite are generally present. The sillimanite is usually in
the mica, but sometimes in quartz (Faserkiesel). This group passes

Vol. 52.] | FOLIATED GRANITES IN EASTERN SUTHERLAND. 643

into Group 2 in the same way as that does into Group1. From
this, and from the abundance of sillimanite, it seems reasonable to
infer that it also is of sedimentary origin. Seams of quartz-schist
occur within it.

Granites occur in all these rocks as veins and sills. Those in the
quartz-schist are red pegmatitic-looking veins, composed of oligoclase,
microcline, quartz, and muscovite; while those in the other schists
about Suisgill contain biotite and very little muscovite, their felspar
being (so far as determined) oligoclase, and sometimes probably
natron-orthose. All these rocks have sharply-defined margins, and
are hardly ever foliated.

Groups 1, 2, 3 follow in order north-westward from Kildonan,
till, about Borrobol, a large mass of Group 2 comes inagain. When
We approach the north-western margin of this, we find that a change
has set in. The granites, which hitherto have not been very
numerous, now appear in great numbers, and ‘injected lit par lit,’
as well as along old faults, now completely healed up by interlocking
crystallization, just as on the coast of Portskerry, forming with the
granulitic schists a ‘ synthetic gneiss.’ A little distance farther on,
however, we leave the granulitic type, and enter a tract of coarse,
wavy, highly crystalline gneiss, like that of Bowside near the
northern coast. Itis composed of quartz, felspar, and very black
mica (often olive-green by transmitted light). The felspars are
large and well striated. They are chiefly oligoclase, but albite and
orthoclase also occur. Garnet is not uncommon, and sillimanite
occurs locally, sometimes most beautifully crystallized.”

In spite of the coarsely crystalline texture of this rock, especially
the large size of its beautiful striated felspars, there is a general
resemblance in structure to the wavy mica-schists of Suisgill, and
in places it could not be distinguished from these; and I am inclined
to believe that, although it may contain other material as well
which has not yet been separated, nevertheless the greater part of
it is the Suisgill mica-schist in a more highly crystalline condition.
It occupies a very large area, extending, with only one interruption
of 14 mile of granulitic gneiss, across the strike, all the way to the
Naver.

Now it is in this rock that the most wonderful granitic intrusions
occur. The phenomena so clearly seen in the cliffs of Strathy Point
are here repeated in their highest intensity. Great sills of granitoid
rocks, often a mile in width, range for miles along the country, and
every gradation exists between these and the very thinnest bands
and seams.

The felspars of these granites are in all cases so far determined
oligoclase, often inclining to andesine, except certain porphyritic
crystals of rather rare occurrence, which are natron-orthose. Albite
and microcline occur in some small pegmatites. The large porphyritic
crystals only are idiomorphic, the rest having the form called by

* These and other minerals were determined during field-work from crushed

fragments under the microscope; laboratory tests being used afterwards, for
eonfirmation in doubtful cases.

644 MESSRS. J. HORNE AND E. GREENLY ON [Nov. 1896,.

Mr. Barrow ‘ round-grained,’ whether in foliated or unfoliated rocks.
The micas are almost always biotite, muscovite being very rare.
Most of the sills are full of inclusions, the smaller sills behaving”
in every respect like the largest. There are no chilled edges
whatsoever.
The junctions are of three kinds :—

(a) ‘ Lit par lit’ injection of a kind more subtle still than that:
where we see parallel beds of schist and granite, for the
margins of a sill fade off into the gneiss through a series of
thinner and thinner lenticles.

(6) The ends of a sill fading off into the gneiss by a dovetailing of
biotitic folia into the granite.

(c) True transgressive junctions, where the granite truncates the:
folia of the biotite-gneiss.

All these three types can be seen in one and the same sill.

Finally, large masses occur in which these relations are carried
to such a degree of intimacy as to render it very difficult to decide
whether to regard them as granite or as gneiss, difficult even to
produce a consistent map, all lines being wholly arbitrary.

The granites are for the most part foliated, the foliation being
generally, as on the northern coast, parallel both to that of the
gneiss and to the sides of the sill. Cases, however, occur of
transgressive junctions where the foliation of the granite follows
the cheeks of the sill or dyke, and so truncates that of the gneiss
(fig. 3). Foliated granitoid rocks can also be seen to truncate each
other, as in Strathy Bay.

Fig. 3.—Foliated granite and biotite-gneiss, southern bank of
Allt Tom na Bradh, Kinbrace.

[Length of section = about 27 feet.]
A = Biotite-gneiss. B = Granite.

Note.—By an error of the draughtsman, the thin dyke of granite (C) at the left
end of the above section has been ‘shaded’ with lines parallel to the sides
of the dyke, instead of lines at right angles to the sides.

The intimate relations here described do not exist in Kildonan.
The granites there are not only smaller and fewer in number, but
they have well-defined margins. As we pass north-westward they
increase, but even in the wavy mica-schists at Suisgill every dyke
and sill is sharply separated from the country rock. The inter-

Vol.52.] | FOLIATED GRANITES IN EASTERN SUTHERLAND. 645

felting and amalgamation come on only in the Kinbrace gneisses.
It is clear, therefore, that even allowing that the structure of the
wavy mica-schists may have been favourable to these types of
injection, the following phenomena are coincident :—

a. Increase in quantity of granite.

QB. Intimacy of relation.

y. Increase of coarseness of crystalline texture in the schists.
6. Appearance and perfection of crystallization of sillimanite.

V. Summary anv ConcLusions.

The foregoing facts suggest important considerations with regard
to the nature of intrusion, foliation, and metamorphism.

It is certain that sedimentary rocks enter into the crystalline
complex, but igneous ‘ contact’ in the ordinary sense cannot be held
to be the sole cause of the regional metamorphism. Fox schists:
closely resembling some of these (especially Gioup 2 of Kildonan)
cover large areas in which no granite is to be seen (sce the descrip-
tion of the schists above the Moine Thrust-plane in Geol. Surv.
Report on N.W. Highlands, Quart. Journ. Geol. Soc. vol. xliv.
1888, p. 378). The whole series, however, is powerfully folded,
and can be shown to have been subjected to shearing stresses,
which perhaps points to the initial cause of metamorphism. That
the granitic injections were closely associated with the meta-
morphic processes we have little doubt; but it appears probable
that they found the schists already crystalline.

What part ‘contact-metamorphism’ actually played is not perfectly
clear. Itis true that as we pass from Kildonan, where granites
are small and few, to Kinbrace, where they are numerous and large,
we do find what has generally been called a ‘progressive meta-
morphism ’ in all rocks which could be expected to show it; that
the intrusive relations at the same time become more and more
intimate ; and that sillimanite appears as we pass in, and is most
beautifully crystallized in the final stages. From which it seems
reasonable to infer that the cause which brought about the intro-
duction of the granite also resulted in these high and peculiar
types of crystallization.

Of foliation in the granites there are several conceivable causes.
Many of the parallel structures are certainly the remains of biotite-
folia belonging to gneisses whose quartzo-felspathic elements have
been incorporated with those of the granite, for every gradation can
be traced from inclusions reiaining their natural orientation (fig. 4, -
p. 646) down to the merest trains of mica-flakes. Probably much
of the foliation is of this nature, at any rate where the gneisses
lent themselves readily to it. But neither this nor dynamo-meta-
morphism can always be appealed to. The numerous cases where the
foliation of the granites can be seen to truncate that of the gneiss
must be borne in mind. How difficult it would be to distinguish
this from the other structure in cases where transgressive junctions.
cannot be observed, the margins consisting of ranges of lenticles !

646 MESSRS. J, HORNE AND E, GREENLY ON [ Nov. 1896,

The orientation of the porphyritic felspars in the granites of
Portskerry, again, can hardly be other than a truly igneous
structure; also the phenomenon of foliated granites cutting each
other’s foliation.

Fig. 4.—Inclusions of hornblende-schist in foliated granite,
Altiphurst, Strathy Point.

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MONS ae th, LSPA ea We AW Pag ROU NIL Rip set uY Neb Sy
US Deke ee n; MPSS tes Toe Zatie IAW “8 XR spk: “ Fe FI iy: Wh AR GE
e ‘ L = ok Sry Lape A pa Gedy
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a dae c wae t RCA EN 5 RX ss “VADs ee Ty v J G cA
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[ Area represented = about 8 square feet. |

Introduction of granite was without doubt the final term in the
production of the gneissose complex, but everything points to that
process having been long and elaborate. Single sections, even, can
be seen showing schists powerfully folded, foliated veins intruded,
the whole faulted, and new and complex veins introduced (figs. 5 & 6).
It is clear that movement must have continued, or recurred from
time to time, from the very first glimpse we get of the metamorphic
process till. nearly its close, for all veins except the microgranites
are cut by faults which are completely ‘ healed up’ by ecrystalliza-
tion.

But it is also clear that the whole mass must have remained ata
high temperature till the very last, not only from the last quoted
fact, but from the absence of any chilled edges whatever, even to
these microgranites, which cut every other rock sharply, and are the
last members of the whole crystalline series.

If, therefore, the rocks ever passed through a stage of mere
mechanical crushing as a result of these movements (and of this the
sections observed afford no evidence), such cataclastic structures
have been wholly effaced during the later stages of metamorphism.

The evidence of powerful movement which these schists every-
where present certainly suggests that such movement was the initial
cause of the whole series of phenomena.

;

Vol. 52.] | FOLIATED GRANITES IN EASTERN SUTHERLAND, 647

With regard to the granites, it is difficult to believe that they are

wholly foreign matter; though here it is necessary to observe the
utmost caution, the chemical difficulties being so great.

In all probability, we must wait for satisfactory solutions of these

Fig. 5.— Veins of granite and pegmatite in hornblende-schist,
north-eastern corner of Armadale Bay.

Sra

/ ee
ye dea Ss
cf 3 Lp

[Face of cliff = about 4 feet square. |

and other problems in metamorphism until much more is known of
the behaviour of the compounds of silicon under high temperature
and pressure. The chemical analogies between silicon and carbon
are known to be close, but whereas the carbon compounds are

Fig. 6.—Details of the smaller vein in fig. 5.

P = Pegmatite. FG = Foliated granite.

singularly tractable under conditions attainable in experiment,
those of silicon are as strikingly intractable. It is not unreasonable
to suppose that the silicon atom may have powers of forming groups
and compound radicals comparable to those of the carbon atom,

648 MESSRS. J. HORNE AND E, GREENLY ON [Nov. 1896,

giving rise to similar series of Protean changes!; but that these
powers are exerted only under conditions which, as yet, preclude
experimental investigation. If we consider, however, what amazing
results have followed the successful investigation of such a series as
CrHon+2, for example, it may well give us pause to reflect on what
may happen under conditions which set the silicon atom also free
to move. ;

Let us hope that the door to further knowledge of these matters
may not always remain closed, though of its opening there is yet
no sign.

Meanwhile the facts described render certain :

1. The existence of relations between granites and crystalline
schists so intimate as to amalgamate the two rocks into
one gneissose complex.

2. That in such regions the schists become more coarsely crystal-
line than they are elsewhere.

3. That some of these schists are of sedimentary origin, and that
aluminous silicates abound in the most highly crystalline
varieties.

. That the foliated structures in the granites are assignable to at
least two modes of origin.

. That, in spite of powerful earth-movements, there is a general
absence of cataclastic structure,

a

Ou

Discussion.

Sir AncHrpaLtp Gurxre remarked that it was curious to see how
the oscillations of geological theory were reviving the views formerly
held, but more recently abandoned, as to the metamorphic origin of
some granites. The Authors of the record of careful observations
contained in this paper were cautious in drawing deductions, but it
was obvious that they were disposed to believe that the granite
described by them, though an eruptive rock, had assimilated the
surrounding schists and was not separated from them by any
sharply-defined differences of composition or structure. Their work
ran on lines closely parallel to that of the French Geological Survey
under M. Michel-Lévy. They were evidently dealing with the
same class of phenomena that had been so closely studied in the
Plateau Central of France. A new line of research had in recent
years been opened up by the study of the intimate blending of
granitic lamine with granulitic and other schists, and though it
was still perhaps too early to formulate a definite theory, a marked
advance had been made towards a comprehension of the conditions
under which granitic intrusions and regional metamorphism are
linked together.

Gen. McManon congratulated the Authors on their interesting
paper, and concurred with them in their main conclusions. He

1 It is not meant that ‘ hydrosilicons’ play the part of the hydrocarbons, but
merely to suggest how much we may have yet to learn regarding silicon.

Vol. 52.) | ¥FOLIATED GRANITES IN EASTERN SUTHERLAND. 649

was interested to see a large specimen on the table illustrating the
fine-grained injection of a rock by granite in thin parallel veins, as
it closely resembled Prof. Bonney’s ‘ granulitic series ’ at the Lizard,
for which the speaker, in his first paper on that region, had sug-
gested a similar origin. He felt some difficulty in criticizing the
paper on one or two points. ‘The Authors suggested that the
‘initial’ metamorphism of the schists into which the granite had
intruded was ‘ perhaps’ due to ‘ shearing stresses’; but the paper,
as read, did not disclose any evidence to prove this contention. The
hypothesis might or might not be true, but he was not prepared to
accept it without sufficient evidence. The metamorphism might be
anterior or posterior to the shearing.

As regards the last point in the paper, the Authors said that the
granite was intrusive, but suggested that it was itself a product of
the metamorphism of the schists. Asthe Authors had not attempted
to unfold this theory, it would be idle to attempt to criticize it. He
would only remark that granite contained highly heated steam,
or water, under great pressure, charged with the mineral matter of
the granite, and as this solution penetrated into the rocks in con-
tact with the granite, they became impregnated with the minerals
of the granite, and might thus appear to blend into granite.

Mr. Tratt said that the Authors had clearly proved that ‘lit par
lit’ injection and other allied phenomena occurred on an extensive
scale in the area in question; but they wisely refrained from
speaking as if they had solved all the problems connected with the
origin of the schists of the district. It was a curious fact that in
several areas granitic rocks were found to be intrusive into gneissose
rocks which closely resembled them in mineralogical composition.

Speaking on the subject of dynamic metamorphism, he remarked
that the rocks into which the granitic magma had been intruded
gave abundant evidence of having been folded and sheared—they
must at one time have been, so to speak, alive with movement—and
he doubted whether a single cubic inch could be found which had not
suffered deformation. At the same time the crystalline grains were
not fractured, so that crystallization must have taken place during
or after the movement. Some critics would apply the theory of
dynamic metamorphism only to those rocks which now possessed
cataclastic structures ; but this limitation had never been contem-
plated or accepted by those who were mainly responsible for its
introduction.

Prof. Jounston-Lavis remarked that the evidence offered by the
Authors as to the high temperature of the matrix-rocks into which
the granite was injected probably inferred also a comparatively
plastic state, which would favour the extraordinarily complicated
ribbon-and-yein structure so characteristic of such regions. High
temperature and the approach to fluidity of materials are, as is well
known, conditions most favourable to chemical interchange and
osmotic diffusion, which are further increased by diversity of chemical
composition of the matrix and the injected material and by the
affinities between the elements of the one and the other. The

650 FOLIATED GRANITES IN EASTERN SUTHERLAND. [ Noy. 1896,

tendency will be, by chemical interchange and osmotic action, to
bring the intrusive rocks and those into which they are intruded
more and more to resemble each other. Granite in small veins,
dykes, and sills can have been formed only in a very hot matrix, in
which heat would remain during long periods of time—conditions
most favourable to the extensive physico-chemical changes of the
intrusive and the intruded rocks. The Authors show how much
material of the granite has been derived from the matrix of the
intrusions, and we must also consider the loss of components from
the granite to the advantage of the matrix. Notwithstanding such
evidence as this, and much more of the same nature, a large school
of geologists persist in referring all the variations in igneous rocks
to internal differentiation and ignore chemical and physical osmosis.

The PresipENT also spoke.

Mr. Greenty, in reply, adduced cases where lenticles of granite
occurring in the schists could not be seen to have any communication
with any other granite-masses. These supported the view that the
granite might not be wholly foreign matter. Referring to remarks
by Gen. McMahon and Mr. Teall, he had never yet seen any region
of crystalline schists in which there was not abundant evidence of
intense earth-movement and deformation. This seemed a fact of
the first importance in the study of these rocks. But the time was
probably still far distant when it would be possible to generalize
concerning them without considerable reserve. He much regretted
the absence of Mr. Horne.

Vol. 52.] | SHISMIC PHENOMENA IN THE BRITISH EMPIRE. 651

38. Seismic Puenomena in the British Empire. By M. F. de
Monressts DE Baxtore, Officer commanding the Garrison
Artillery at Nantes. (Translated by L. L. Bretinranre, B.Sc.,
B. és L. Communicated by Sir Arcurpatp Guixre, F.R.S.
Read June 10th, 1896.)

[ Abridged. ]
[Puares XXX.-XXXITII.]

I. Inrropvucrory.

Wiruoor pretending to have discovered the primary cause of earth-
quakes, the author is firmly convinced that the plan which he has
been elaborating for some years will reduce the present chaos of
seismological study to some sort of order, and will enable others to
go farther than he has done. This plan is made up of four parts,
and the present paper, which deals with the British Empire, is a
section of the third part now approaching completion. These four
parts, three of which will be briefly outlined in the following
pages, are :—

(1) Formation of an Earthquake Catalogue.

(2) Refutation of the empirical laws previously enunciated.

(3) Description of the globe from the seismic point of view.

(4) Study of seismic phenomena in the United Kingdom and the
British Colonies. __

Il. Formation oF AN EARTHQUAKE CATALOGUE,

More than 100,000 observations of earthquakes have been brought
together, 6175 of which have been made use of in the present work.

These observations vary much in value; when they are the result
of isolated narratives, gathered from documents of all kinds (but the
object of none of which is the special study of earthquakes), we get
so-called ‘ historical series,’ generally of little account. If, on the
other hand, scientific men have especially busied themselves with
these phenomena in any particular country, and have taken careful
note of the earthquakes felt by them or reported to them, we get
so-called ‘seismological series’ whose value is the greater the
larger the number of years covered by them. Then too some countries
are equipped with special observatories containing self-registering
seismographs; these furnish so-called ‘ seismographical series’ of
very considerable value. It has, however, been shown that these
series are not absolutely reliable, because the apparatus being too
sensitive and being placed too near great centres of population is apt
to register all sorts of vibrations, some of which are due to the
passage of heavy railway-trains, or to operations connected with the
laying of roads, of gas- and water-mains, etc., and have, of course,
nothing to do with true seismic movements.

Q.J.G.8. No. 208. 2¥

652 M. F. DE MONTESSUS DE BALLORE ON [Nov. 1896,

ITI. Descrrprion or THE Giope ¥Rom A Sersmic Pornt or VIEW.

The earthquake-catalogues inform us that in such and such a
locality so many shocks have been reported. Now it very often
happens that this locality is not the focal centre of the phenomenon.
But earth-shocks in general have a smaller ‘area of activity’ than —
one might imagine from the narratives of great earthquakes. It
has been demonstrated that this area, as a general rule, covers a
surface far smaller than that described by a circle of 124 miles
radius. Consequently the smaller earthquakes, such as are known
to have shaken only one locality—and these are by far the most
numerous,—are sufficient for showing upon the map the distribution
and density of the centres of seismic movement; for, if we do not
as a rule know which is the real centre, at least we know a point
which is usually much nearer to it than 123 miles. By grouping
these localities or centres one is enabled to define on the map
regions of greater or less stability. It is well, for the sake of giving
these rational boundaries, to make use of the chief topographical
features of the country—mountains, rivers, seas, ete.

It remains now to find a numerical value for the greater or less
stability of a region, what we may in a word term its ‘ seismicity.’
Mallet did by implication trench upon the problem (Fourth Report
upon the Facts and Theory of Earthquake-phenomena, Proc. Brit.
Assoc. 1858). He drew out a map of the world whereon graduated
shading represented the frequency and intensity of earthquakes in
various parts of the globe. Unfortunately he had to base his work
on estimates, in the absence of actual data. The result was that he
often fell into serious error—as, for example, with regard to the
Antarctic region, a very stable area. Moreover, that deeply learned
seismologist appears to have confounded seismicity with vulcanicity
—two entirely different and independent factors, pace the usually
received opinions.

O’Reilly (Trans. Roy. Irish Acad. 1884). published a seismical
chart of Great Britain, and it is a matter for deep regret that the
similar chart of Europe (foreshadowed in his highly important
alphabetical catalogue of earthquakes in that part of the globe
and adjacent regions, op. cit. 1886) was never published. These
documents, though extremely interesting, are difficult to utilize
because they record every shock felt in each locality indicated,
without any attempt on the author’s part to show whether these
localities were centres of vibration or were at all near the centre.

The seismicity of a given area evidently depends upon the number
and intensity of the shocks felt within that area. The first factor
may be easily tabled, but one cannot say the same of the second.
Very fortunately we are enabled to eliminate it for two reasons:
the number and intensity of earthquakes are practically proportional
in any particular country—by which it is meant that they are
severe only where they are frequent, and conversely—provided that
we take into account a sufficiently long lapse of time. Moreover,
feeble shocks being enormously more frequent than severe shocks,
we may neglect the latter in the present investigation.

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 653

Thus is one enabled to define the seismicity of a region by the
inverse of the square root of an area in which on an average one
shock occurs every year. Let us suppose that during a period of
years p shocks have been recorded in a region of superficies A, then its

eismicity S will be expressed by the inverse of a/ doe practice,

nv

we make use of this numerical expression, so that seismicity or insta-
bility is the greater the less the number of square miles. The map
of the region just dealt with may then be covered with equidistant
lines arranged according to the scale thus found. The surface,
neglecting a slight error due to irregularity of contours, is then
divided into small primary squares wherein one earthquake occurs
in each year. As arule, the scale of maps is not such as to allow
of this extremely rational equidistance of divisions.

The data of seismicity thus calculated will be the more exact the
greater the number of years over which observations have extended ;
the data will vary also according to the nature of the observations upon
which they are based—whether historical, seismological, or seismo-
graphical, as defined above. In order to base any reasoning upon
the results it is evidently necessary that the calculated ‘ seismicities ’
should all be derived from observations of the same order. Now,
any given country can only furnish observations of one order. But
the defect, if defect there be, may be made good.

Let us represent the seismicities by the expressions S), 8,, S,,
according as they have been deduced from historical, seismological,
or seismographical observations. In 94 cases per cent. the values
of the relations of the three ‘seismicities’ one to the other are
known, and one may therefore obtain from these certain empirical
formule which will serve to calculate any given seismicity by
means of the two others. Seismographical observations being few
and far between, the seismological seismicities, observed or calculated
as above mentioned, have been taken as the standard. We have
here the sole means of making rational comparisons.

IY. Srupy or Sxismic PHENoMENA IN THH Unirep Kinepom AND
THE BritisH Cotoniss.!

§1. The British Isles, (PI. XXX. & fig. 1, p. 654.)

Historical records regarding earthquakes are, so far as regards
the British Isles, numerous and valuable. On the other hand, the
earth’s crust here is very stable, and earthquakes in Britain have
never caused any serious damage. Seismological documents, and
a fortiori seismographical documents, are conspicuous by their
absence.

The number of shocks recorded is 1023, felt in 221 localities
scattered over 10 definite areas.

? Calculated seismological seismicities are distinguished in the following
pages by an asterisk.
2¥2

654 M. F. DE MONTESSUS DE BALLORE ON [Novy. 1896,

Pigoie

MAP OF THE

BRITISH ISLES

SHOWING THE

SEISMICAL REGIONS.

By F.de Moztessus
de Ballore,

>
=P
a \CENTRAL
| | S38

ward EEE ED EAST
|

mal Southern England 55 Km.

FRE Lowlands of Scotland 35 Km, cee Moray Firth 58 Km

FEA feed South Eastern Ireland 78 Km.
Perthshire étc. 40.Km. Wales 76 Km.

EEF Central England 49 Km. ae Last Anglia 96 Km.

1. Scottish Lowlands.

S,= 63 kilom. (1886-1889). S,*=31 kilom.
(18 localities and 24 shocks.)

This region is limited by the Firth of Clyde, Loch Long up to
Ben Voirlich, the valley of Loch Lomond, the Firth of Forth, the

German Geers: and then the Scottish Border from Berwick to
Longtown.

2. Perthshire and North-eastern Coast of Scotland.
S,=72 kilom. (1852-1890). S8,*=35 kilom.
(21 localities and 465 shocks, )

This region is bounded by the preceding one, by the North Sea,
then by a line of heights separating the Dee from the Don. The

Quart. Journ. Geol. Soc. Vol. LIT. Pl. XXX.

Unst 1.3

ge

eTinafuline

Turriff 2

Invernes

ee *Strathglass

of SeGlen Gp fry2
x ne ey %
~
y oy Aber™ '
cia Sep,

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DUMFRIES

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eRipon
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5 H&lifax “
eDoncaster

Manchester.2
eSheffield

eLincoln 4
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ser’? xo eBarnage Cric e

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a as @Ledmiugton ¢
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Jersey or

To face p. 654.)

MAP oF THE

BRITISH ISLES

SHOWING

SEISMICAL LOCALITIES.

By F. de Montessus de Ballore.

The numbers are those of
the recorded shocks.

Ballymore
Dublin
Kingstowit

Wicklow
Tinahely

Wexford 2

8

Charleville

Cork 5

aN

. St
Reilly 18s, Mary.

Kintail S eStrathglas

oy he ae
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AS

© *Logierait
*Comeic@Asniirie
jef 2
ost opeftha Firth of Tay
eDunuing

Rilsyth
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: Galashiels

Wanloch Head 2

Tyneheade,
DUMFRIES

Dumfries 3e

eRipon

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ie. Veatherby 2
~Methley

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Manchester.2 OU SRG

Sheffield

elincoln 4

Chester8 Mansfielde

angor
Nottingham
‘ ; °
lM jddle Derbye @ Beeston 5
&S eto on ch
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lee | eBrowood Forest °
Jey He Qvittenball
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eEly

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Shaftesbury
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SURREY ®MMoulsey”
Sutton

Hastings
SUSSEX Lewes
°

Pl, XXX.

a 9

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 655

boundary runs along to Ben Voirlich by Cairn Celar and Ben Aber.
On several occasions, and more particularly between 1839 and 1852,
this region has been visited by several shocks in the valleys of Loch
Tay and Loch Earn, and above all at Comrie. The last-named
locality is the most unstable spot in the British Isles.

3. Northern and Central England.

- £§,=89 kilom, (1833-1873). S,=44 kilom.
(65 localities and 159 shocks.)

This region is limited by the two seas, and by three conventional
lines running from Irton to Muston, from Chester to Newport (Mon.),
from Newham to the Wash. The most unstable portions are
situated on the southern slope of the Welsh mountains and in the
middle part of the Severn Valley.

4, English Coast of the Channel.

S,=99 kilom. (1848-1871). S,*=49 kilom.
(50 localities and 135 shocks.)

This region is bounded on the north by a conventional line
running from Bristol to London. It is particularly unstable in the
Cornish and Dartmoor areas. From the seismic point of view the
Scilly Isles must be included in it.

5. Caledonian Canal.

S,= 105 kilom, (1852-1871). S,*=52 kilom.
(27 localities and 54 shocks.)

This region is bounded by the heights of Monadh Liadh between
the Findhorn and the Spey, and by a conventional line drawn from
Loch Broom to the Moray Firth through Ben Wyvis. It extends
through the Western Isles as far south as Phadda.

6. South-eastern Ireland.

S, = 182 kilom. (1852-1880). S,*=65 kilom.
(12 localities and 19 shocks.)

Ireland, very stable as a whole, has only one area subject {io
earthquakes, and that is the south-east. This is bounded by the sea
and by a conventional line drawn from Dublin to Kinsale through
Charleville. The portion most often shaken is Cork Harbour.

7. Wales.

S,=1388 kilom. (1839-1894). S,;*=68 kilom.
(16 localities and 29 shocks.)

This region is bounded on the east by a conventional line drawn
from Chester to Newport (Mon.). As it possesses much the same
seismicity as South-eastern Ireland, the recorder is tempted to throw
the two regions into one—bridging over St. George’s Channel.

656 M. F. DE MONTESSUS DE BALLORE ON [Nov. 1896,

8. East Anglia.

S\=174 kilom. (1848-1871). S,*=86 kilom.
(10 localities and 18 shocks.)

This very stable area is bounded by the North Sea, from the
Wash to the estuary of the Thames, and cuts like a wedge into
the heart of England up to the Bristol Channel.

9. North-eastern Scotland.

This is an extremely stable area, only 11 shocks having been
recorded: they occurred in 5 localities.

10. Shetland Isles.

In these islands shocks are rarely felt, unless they be those trans-
mitted from Scotland or Norway. Nevertheless, 5 shocks proper
to the Shetlands have been recorded.

England and Scotland.

Together : S,=185 kilom. S,*=91 kilom.
England alone: S,=193 kilom. S, =95 kilom.

§2. India. (Pl. XXXI.)

The study of earthquakes has never received due attention in
India, notwithstanding the colossal disasters which have wrought
havoc in Kashmir and Burma. We possess, however, a good seis-
mological series of records from Assam. Historical documents in
India regarding earthquakes are of very small value. Altogether
761 shocks have been recorded from 136 localities spread over
13 regions.

1. Upper Panjab and Kashmir.

S,=41 kilom. (1885-1886), S,=20 kilom.
(7 localities and 48 shocks.)

The real boundaries of this area are just as much a matter of
dispute as the value of its ‘ historical seismicity.’ Undoubtedly its
instability. is great—as may be inferred from the catastrophes
which have befalien Kashmir and the frequent recurrence of earth-
quakes in the Upper Panjab.

2. Assam. (Fig. 2, p. 657.)

S,=114 kilom. (1839-1849). S,=34 kilom. (1874-1880).
(21 localities and 228 shocks.)

This extremely unstable region has been very well studied from
the seismic point of view. It is bounded by the Brahmaputra
from Karhharbari to Sudyah, and by a conventional line which

Quart. Journ. Geol. Soc. Vol. LIT. Pl, XXXI.

INDIAN EMPIRE

4 Upper Panjab & Kashinir Kumaon; Nepal & Sikkim 117 Km.
23 Km. Kach and Sindh 108 Km

Assam 34 Km. Sei Ganges Basin and Bengal 130 Km.
| Gujerat, Bombay; and
Central Hindustan 75 Km, Deccan 283 Km.

Kilometrical Seismicities and
Seismical Localities.

(REESE:
CHANGERS

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OR ISLAMABAD

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SINGAPORE 5

To face p. 656. | Quart. Journ. Geol. Soc. Vol. LIT. Pl, XXXI.

PADAGSSHAN INDIAN EMPIRE

UE
KABUL a5

23 Ko, Kach and Sindh 108 Km

H dssam 34 Km. : | Ganges Basin and Bengal 130 Km.

ar Gijerat, Bombay; and
|_| I | Central Hindustan 75 Km, [fe] Deccan 283? Km.

Upper Panjab & Kashmir | Kionaon; Nepal & Sikkin 117 Kon

LAHORE 7@
PANJAB 6 A Kilometrical Seismicities and
OQuETTA3 SULTAN Seismical Localities.

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The numbers after place-names are
those of the recoxded shocks.

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 657

leaves Manipur south of it, but includes within the area the middle
and upper valleys of the Barak and its right-bank affluents. Centres
of vibration are closely clustered together, and severe shocks have
been often felt.

ASSAM.

Kilometrical Seismicity
and Seismical Localities.

Goalpara 5@6) pot
a '

The numbers after place-
: B names are those of the
FA adssam 34 Km. recorded shocks.

3. Gujerat and Bombay.
S,=135 kilom. (1868-1872). S,*=66 kilom.
(17 localities and 53 shocks.)

The boundaries of this region are very indefinite. There is a
rather unstable centre of vibration on the southern flank of the
Mahadeva Range.

4, Kdach and Sindh.

S,=195 kilom. (1841-1846, 1864-1870). S,*=96 kilom.
(11 localities and 86 shocks.)

In this region there is a remarkable centre of vibration in the
neighbourhood of Lakpat. As to the famous upheaval of the levée
of Allah or Bhudj, that is a phenomenon which in all probability
had nothing seismic about it.

5. Kumdon, Nepal, and Sikkim.

S,=212 kilom. (1828-1833, 1842-1843). S,*=104 kilom.
(11 localities and 33 shocks.)

This region, which includes the southern slopes of the Himalayas,
is probably much more unstable than the above figures would appear
to indicate. Darjiling and Sikkim are frequently shaken by earth-
quakes.

Southern slope of the Himalayas :

S,=71 kilom., S,*=35 kilom.

658 M. F. DE MONTESSUS DE BALLORE ON [Nov. 1896,

6. Ganges and Bengal.

S, = 234 kilom. (1870-1872). S,*=115 kilom.
(16 localities and 46 shocks.)

This region, comprising the valleys of the Ganges and its left-
bank tributaries up to the first slopes of the Himalayas, is in all
probability fairly stable. However, Benares has at times suffered
some considerable damage.

7. Deccan.

S,=511 kilom. (1865-1873). S,*=251 kilom.
(11 localities and 16 shocks.)
This region covers the whole of Southern India, and is very
stable.
8. Panjab and Afghanistan.

(14 localities and 66 shocks.)

Failing sufficient data, it has been impossible to calculate the
seismicity for this region and the following ones. The neighbour-
hood cf Kabul, the valley of Badakhshan, and above all that of
Khorum are frequently subjected to earthquakes, which are some-
times rather severe.

9. Ceylon.
(7 localities and 10 shocks.)
This isiand appears to be very stable.

British Indian Empire:
iS, = 76 kilom. S83 lalom:

10. Arrakan and Burma.
(7 localities and 19 shocks.)

According to Adolf Bastian, shocks of earthquake are frequent
in Arrakan, and so very customary in Burma that no notice is
taken of them. Anquetil asserts that the surface of Burma is
covered with ruins caused by these seismic phenomena, and account
is taken of earthquakes in the method of constructing houses and
other buildings. Nevertheless, there are few important cities which
have not been several times completely destroyed, such as Arrakan,
Promé, Paghan-mhy6, Ratnapur, Ava, and Amarapura. Exact data
are, however, still to seek.

ll. Malay Peninsula.
(3 localities and 11 shocks.)

The southern extremity of this peninsula receives pretty fre-
quently the vibration of the shocks from Atcheen.

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 659

12. Islands in the Indian Ocean.
(5 localities and 125 shocks.)

The Andaman Isles, and especially the Nicobars, seem to possess
little stability. The islet of Kendoel in the last-mentioned group
has been the site of a great many earthquakes. The Maldives and
the Laccadives, on the other hand, appear to be fairly stable.

13. Indo-China.
(6 localities and 7 shocks.)

Indo-China is geographically connected with Hindustan, and is
therefore quite naturally mentioned here. The absolute silence of
all explorers regarding seismic phenomena in this region might lead
one to infer that it is extremely stable, at least as a general rule.
In Tongking it sometimes happens that vibrations are felt, propa-
gated from the earthquakes taking place in Yunnan.

§ 3. New Zealand and Australia. (Figs. 3 & 4.)

Of Australia, next to nothing is known from the seismic point of
view, and very little is known from this standpoint of Tasmania
either. But the matter is far otherwise with New Zealand, which
makes, with Assam, the only two British colonies where earthquakes
have been studied with some degree of care. Earthquakes are
frequent in New Zealand, but are rarely very destructive. The
two islands have perhaps more to fear from the great tidal waves
propagated from far-distant Chile, after having traversed unim-
peded the entire breadth of the Southern Pacific. From 25 years
back, thanks to the labours of Sir James Hector, we possess a fine
seismological series of observations embracing the whole colony,
with the exception of two comparatively sparsely-populated dis-
tricts—the northern end of the North Island beyond Auckland, and
the western coast of the Middle Island. There have been recorded
1840 shocks from 81 localities distributed over 7 regions.

1. Cook Strait.

S,=71 kilom. (1846-1848, 1863, 1868-1888).
(18 localities and 1444 shocks.)

This district bridges over Cook Strait, and its submerged portion
is, of course, taken into account in the calculation of the seismicity.
It comprises the two watersheds on either shore of the Strait.
The dry-land boundaries are, on the north, a line drawn from Mount
Whareorino to Cape Palliser, and on the south a line drawn from
Cape Farewell to Mount Kaikorara. The town of Wellington was
overtaken by a great disaster in November 1848.

Fig. 3.

NEW
ZEALAND.

Kilometrical Seismicities
and
Seismical Localities.

Auckvayp 200

4)
The numbers after place- |_|
names are those of the
recorded shocks.

GREYMOUTH 58

fa
a ||
Li

ne
a

a
4

STEWART 1.2

ame

Cook's Strait 77 Ki.

Auckland 130 .K70.
Canterbury 137 Kim.
Otago 138 Ki.

West Coast 143 Km.

:
4
7
a

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 661

2. Auckland.

S,=130 kilom. (1869-1888).
(18 localities and 90 shocks.)

This region, comprising the volcanic districts of Tongariro, Lake
Taupo, and Rotorua, is bounded on the south by the preceding
region, and on the north by the isthmus of Auckland. Its feeble
seismicity in comparison with that of Cook Strait is a notable example
of the independence of seismic and volcanic phenomena
one from the other.

3. Canterbury.

S,= 137 kilom. (1868-1888).
(10 localities and 68 shocks.)

This region is bounded on the north by the Cook Strait area,
on the west by the longitudinal mountainous ridge which forms the
backbone of Middle Island between Mounts Franklin and Stokes,
and on the south by the northern slope of the Molyneux river-basin.
The considerable upheaval of the coast-line, which has been claimed
as an effect of the great earthquake of 1869, can hardly be
admitted unless better proofs are forthcoming than those hitherto
advanced.

4. Otago and Stewart Island.
S,= 138 kilom. (1871-1888).
(5 localities and 47 shocks.)

This region comprises the Molyneux river-basin and Stewart
Island. It is bounded by the preceding region and by the range
running from Mount Stokes to Tewaewae Bay. As it has much the
same seismicity as the preceding region, it might well have formed
with it one single area—the eastern slope of the Middle Island.

5. Western coast of the Middle Island.

S,=143 kilom. (1870-1888).
(5 localities and 21 shocks.)
The seismicity of this region is not very well known.

New Zealand; S,=103 kilom.,
6. Tasmania. (Fig. 4, p. 662.)

S,=390 kilom. (1859-1884). S,*=192 kilom.
(6 localities and 10 shocks.)

These values for the seismicity are very uncertain.

7. Australia. (Fig. 4, p. 662.)
(24 localities and 71 shocks.)

For want of sufficient data it has been found impossible to calculate
the seismicity of this island-continent. There is reason to suspect
the existence of an unstable region along Bass’s Strait, and that of
another in the upper basin of the Murrumbidgee.

662 M. F, DE MONTESSUS DE BALLORE ON [Nov. 1896,

Fig. 4.

AND Marlboroughe ”
TASMANIA.
Seismical Localities.
The numbers after place-
names are those of the
recorded shocks- S
g&
&
>

Macquarie

gSydney 5

z=
A
~)
Wagga Wagga 4@ & Fstramatta
>
uy
2

Araluene ¢ Candelo

Melbournel8@ GGabo 1

Port Albert

D

Cireular Head 392.
TASMAN jab eal

Kilometrical Seismicity
of Tasmania 216 Ki.

§4. Africa. (Pl. XXXII.)

The vast extent of the British possessions in Africa accounts for
the inclusion of a seismic description of this continent (with the
exception of the Barbary coast) in the present memoir. Taken as
a whole, data are wanting, and only for a few localities do we
possess some information—and that more or less vague—as to the
intensity and frequency of earthquakes. The groups of islands
situated in the Atlantic are not dealt with here.

195 shocks have been recorded from 64 localities.

Historians mention a certain number of earthquakes in Egypt,
but these are merely vibrations propagated from Syria.

According to d’Abbadie, shocks are of common occurrence at
Massowah, and at Imakulla in Samhar. Or. Blanc, however,
records only two shocks at Massowah between February Ist and
September 30th, 1864. Kaufmann avers that earthquakes are
frequent and severe at Gondokoro, and that they very probably
originate from Mount Logwack or Logwat, south of that town.
On Th. Kotschy’s map this is called the Erdbebenberg, or Karthquake
Hill, a highly suggestive name. The preceding information is con-
firmed by the missionary Father Dovyak.

Earthquakes are sufficiently frequent and severe on the Guinea
coast between Accra and St. George d’Elmira, but are of rare
occurrence on the Senegal coast.

A centre of vibration appears to exist not far from Bu Suada, on
the borders of the Sahara.

fES

a
DICK

Quart. Journ. Geol. Soc. Vol, LIT. Pl. XXXII.

®MURZUK

NAMAQUA

THEBES 30

KHARTUMe

LOGHWAT MT.®

@SINGATINI

BETHESDA®

ALEXANDRIA Y

Cairo 1g @OlSMacia 2

The numbers after place-
names are those of the
recorded shocks.

@MEDINA 2

e
MASCAT

MECCA 3
SUAKIM

BERBER®

IMAKULLA 5@

GONDAR 29
BETALIHEM®

SAQUAS M4, (0)
2

@Gonvokoro
®MouGi

°
UNYANYEMBE

®KAVALA

COMORRE 2
°

MAPEMBA®
MOZAMBIQUE:

TETE 30

ANTANANARIVO 11

2, AMATAVE
eBETAFO MAURITIUS +

e
FIANAR SOA REUNION 9

e
INHAMBANES

S.MARIE 4

To face p. 662. | - Quart. Journ. Geol. Soc. Vol, LIT, Pl. XXXII.

The numbers after place-
names are those of the
recorded shocks.

@
MEL EL/DICK
@olsmacia 2

°
OK AGADIR % GHADHANES Cairo 13

eMURZUK THEBES 30
@MEDINA 2

@MECOAS

SUAKIM
BeERBER®

Snecues KHARTUMe
SENEGAL IMAKULLA 5@
GONDAR 29
BETALIHEM®

SIERRA LEONE 3

@Gonvokono

Mousa!
LOGHWaT MT.®

*SINGATINI

UNYANYEMBE

@s.Hecenns RIVO TT

AMATAVE
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REUNIOND

INHAMBANES

Seismical, Localities NAMAQUA pe rHESOAS
in

AFRICA
(Excepting Algeria and Tunisia.) STELLENBOSC

CAPE TOWN I7

a.)

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 663

Morocco is a stable region so far as the interior is concerned, but
it is unstable along the Mediterranean coast between Tangier and
Ceuta.

Tunisia is stable, save along the coast of the Gulf of Gabes.
Utica was the scene of many disastrous earthquakes when under
Roman rule.

If we may believe Livingstone, earthquakes are unknown on the
Upper Zambesi, at Victoria Falls, or in the hills through which runs
the tributary of the Kafue. The same explorer learnt at Tete, on
the Zambesi, that in the Maravis country, a short distance from
that town, slight shocks are frequently felt.

On the Mozambique coast and at Senna slight shocks are fre-
quent, and all come from the east, which circumstance has caused
Perry to ascribe them to the active volcano of Réunion—a view
which the distance makes inadmissible, and moreover very few
earthquakes occur there.

Lake Tanganyika, on the other hand, and the Upper Congo towards
Stanley Falls, may well include some important centre of seismic
movement.

Earthquakes are rare at the Cape of Good Hope. A centre of
seismic movement possibly exists in Namaqualand, at Rehoboth,
where, according to Henderson, subterranean noises and slight
shocks are frequently observed.

Despite the activity of the volcanoes of Mauritius, Réunion, and
the Comoro Group, earthquakes are of rare occurrence in those
islands.

Of Madagascar little is known, in so far as seismic phenomena
are concerned, save that the eastern
slope is often more shaken than the Fig. 5.
western.

From St. Helena 8 shocks have
been recorded, and 2 from Tristan
Dacunha, but none from Ascension.

BRITISH COLUMBIA Jf

Kilometrical Seismicity.

§5. Dominion of Canada.
(Fig. 6, p. 664.)

A good series of historical records
is available for the St. Lawrence
basin, New Brunswick, and Cape
Breton Island, colonies where earth-
quakes frequently occur. Moreover,
it is known that Newfoundland
and Labrador are very stable.
The Quadra Archipelago and
Vancouver share in the instability of Washington Territory, and to
the two former the seismicity of the last named may be fairly
applied (S,=118 kilom. ; S,*=58 kilom.).

The Queen Charlotte group appears to be extremely unstable.
As to the vast level plains which stretch between Hudson Bay and the
Mackenzie River, and the islands of the Arctic Ocean, we are entitled

Vancouver Id. 66 Km,

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Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 665

to ascribe to them the same stability as that which characterizes
the plains of Russia and Siberia.

Records are at hand of 147 shocks in 69 localities distributed
over 3 regions.

1. Valley of the St. Lawrence.

S,=120 kilom. (1879-1888). S,*=59 kilom.
(23 localities and 81 shocks.)

This seismic region merely constitutes a narrow band along both
banks of the river, from the point where it issues from Lake
Ontario down to Metis.

2. Northern Shores of Lakes Erie and Ontario.

S,=163 kilom. (1877-1885). S,*=:80 kilom.
(14 localities and 16 shocks.)

This seismic region is also very narrow. Quinte Bay and the
isthmus between the two lakes appear to be the points of least
stability.

3. Nova Scotia, New Brunswick, and Cape Breton.

S,=278 kilom. (1847-1853, 1884-1886). S,*=137 kilom.
(13 localities and 13 shocks.)

This region is bounded on the west by a conventional line drawn
from Nepisiguit Bay, and including the Bay of Fundy.

§6. Scattered Possessions.

1. Channel Islands.

Here 12 shocks have been recorded from 3 localities. The islands
are often shaken by vibrations propagated from the neighbouring
French coast, and one may apply the seismicity of the latter to
them (S,=171 kilom.; S,*=84 kilom.),

2. Gibraltar.

The peninsula of Gibraltar belongs to a seismic region in Spanish
territory, whose seismicity is expressed by S,*=102kilom. Larth-
quakes are of common occurrence, because of the neighbourhood of
the very unstable region of Malaga. From the Gibraltar district
19 shocks have been recorded, and 2 from the Straits.

666 M. F, DE MONTESSUS DE BALLORE ON [Nov. 1896,

3. Maltese Islands. | ie 7.
(Fig. 7.)

These islands are not very
stable, but they are, at all

events, more stable than Lets
oO

Sicily. From them 65 oe.
earthquakes are recorded. ie
© <a...
4. Cyprus. (Fig. 8.)
The vibrations propa-
gated from earthquakes in MAL TA

Anatolia or Syria have
been of frequent occur-

rence in this island, and Fig. 8.
on some occasions have

caused damage. It 18 ff] rhe numbers after place-
not certain whether many HS Tra ee

ee z recorded shocks.
earthquakes originate in :

Cyprus; only 14 are cer-
tainly known to have ori-
ginated there. Lee

5. Aden.

Shocks are not so very | CYPRUS.
uncommon at Aden, and f =
5 have been recorded there.

6. Shanghai and Hongkong.

Shocks are of fairly frequent occurrence in both these localities.
They are also shaken by the vibrations propagated from the more
considerable earthquakes of Formosa. From Shanghai 12 shocks
are recorded, and 5 from Hongkong. From Port Hamilton no
records are available.

7. Virgin Islands.

S, =47 kilom. (1864-1866). S,*=23 kilom.
S/'=66 kilom. (1869-1879). S',*=32 kilom.
(5 localities and 656 shocks.)

The Virgin Islands, more especially St. Thomas, are particularly
unstable. 1t is not easy to say which is the most reliable of the
pairs of values given above for the seismicity, for the period
1864-1866 is very short, and was perhaps preliminary to the
great cataclysm of 1867-1868. In this region, submerged areas
are, of course, included, and this must be so in the case of all
groups of islands.

LA

z2

Quart. Journ. Geol. Soc, Vol, LI. Pl. XX XIII.

vs LESSER ANTILLES B10

2} Becierivs Seismical Localities.

—]o The numbers are those of
as the recorded shocks.
@
aBh P we”
gust ° ANTIGUA 177
<x? fs)
ew Nevis
an?
St. FALMOUTH

4

GUADELOUPE 505
oO

co)

oP

Les SAINTES 5

DOMINICA 1.18
ARIGOT

ROSEAU 3

ST.PIERRE 22 MARTINIQUE I22
FORT DE FRANCE 4
8. Lucia 20
6 207 BARBADOS 12

GRENADA 12
ST.GEORGE 2

a 12

. te .

To face p. 666.)

Q @st Martin 4

Quart. Journ. Geol. Soc, Vol, LI. Pl. XXXIII.

LESSER ANTILLES ETC,

Seismical Localities.

The numbers are those of
N the recorded shocks.

ANTIGUA 177

FALMOUTH

%

Sketch-map of the
Kilometrical Seismicities
in the

LESSER ANTILLES, Eve.

Virgin Is.26 Km.
fa Lesser Antilles 48 Km.
Gulf of Paria,
Trinidad & Tobago Id.68 Kim.

(GUADELOUPE 505
Oo

ca}

Les SAINTES 5 @®

Dominica |.18}a

ROSEAU

ST.PIERRE 22 MARTINIQUE 122
FORT DE FRANCE 4
&: Lucia 20
6 207 BARBADOS 12

GRENADA 12
ST.GEORGE 2

Birvs 12

rs

Vol. 52.] | SEISMIC PHENOMENA IN THE BRITISH EMPIRE. 667

8. Jamaica. (Fig. 9.)
S,=66 kilom. (1847-1873). S,*=32 kilom.
(17 localities and 157 shocks.)
This is a very unstable island, and it has been the scene of many
a violent earthquake. As most of the shocks recorded were felt at
Kingston and Port Royal, it is impossible to say which of the two
slopes, northern or southern, is most often shaken.

Fig. 9.

JAMAICA

Kilometrical Seismicities

. - AND )*
Seismical Localities.

i=
rT TT ties
BORIS RRR OARS’
Pry = SS

= ~*

- J The numbers after place-names are
Ee Famaica 36 Km. those of the recorded shocks.

9. The Lesser Antilles or Windward Islands. (Pl. XXXIII.)
S,=86 kilom. (1845-1871). S,*=42 kilom.
(37 localities and 1189 shocks.)

This group, wherein the islands belonging to Britain are suffi-
ciently numerous to warrant its inclusion here, is somewhat unstable.
Severe shocks have been recorded from it. Nevertheless, its seis-
micity is lower than the presence of numerous active and extinct
volcanoes would lead one to suppose.

10. Tobago and Trinidad.
These two islands form part of a seismic region which comprises

the north-eastern portion of Venezuela, and they have the same
seismicity (S,=68 kilom., S,* =33 kilom.). 4 localities and 62 shocks.

Fig. 10.

11. British Honduras.
(Fig. 10.)

S\*=85 kilom (1846-1856).
S,*=42 kilom,
(8 shocks recorded from
Belize.)

This seismic area is formed
by the coast stretching be-
tween Belize and Trujillo, along
the Gulf of Honduras, but it
probably extends into the inte-

BRITISH HONDURAS

T1or as well. ame British Honduras 47 Km.

Q.J.G.8. No. 208.

668 SEISMIC PHENOMENA IN THE BRITISH EMPIRE. [ Noy. 1896,

12. British Guiana. (Fig. 11.)

The Guianas are generally stable, and the few shocks felt there
come from the Parian Gulf or the
West Indies. . Fig. 11.

2 localities and 3 earthquakes p= sca can
(originating 7 loco) in British ©
Guiana.

| BRITISH GUIANA. |
Seismical Localities.

13. Other Possessions.
(Figs. 12 & 13.)

The Falkland Isles are certainly
extremely stable. British Borneo
and British New Guinea are pro-
bably stable too. On the other
hand, the converse proposition
would appear applicable to the
Fiji and the Chatham Groups. Figs. 12 & 13.
Labuan is apparently stable.

In conclusion the author con-
siders it highly desirable that
English observers, and meteoro-
logists in particular, disseminated ye
in all these colonies should care- | wiv
fully note all the shocks that occur.
The preceding pages have shown
how many parts of this vast empire
are comparatively unknown from CHATHAM ISLAND
the seismic point of view. a

Puares XXX.-XXXIII. Zo
Seismical maps of the British Isles, the v
Indian Empire, Africa, and the Lesser ne
Antilles. PORT HAMILTON 9

Drscusston. BERMUDA ISLANDS. |

Sir ArncHrBaLp GerKxiz referred |
to the published work of the
Author in seismology and the laborious nature of the investi-
gations which he had summarized in the present paper. His idea
of ‘seismicity’ was an original one, and, besides being simple
and ingenious, seemed to offer a more satisfactory standard of
comparison than had previously been available.

The speaker, in communicating this paper to the Society, referred to
the recent death of the Foreign Member of the Society, Prof. Daubrée,
at whose request he had undertaken to bring M. Montessus de
Ballore’s investigations before the geological public in this country.

Prof. Jounston-Lavis also spoke.

Vol. 52.] THE UPPER PORTION OF DUNDRY HILL, ‘669

‘

39. Dunpry! Hitt: tts Uprer Portion, or the BEDS MARKED us
Iyrerior Oorite (g 5) in the Mars of the Geotogican Survey.
By 8. S. Bucxman, Esq., F.G.S., and E. Witson, Esq., F.G.S.
(Read May 13th, 1896.)

ConTENTS,
Page
PE TUCSE RESID oat sea acre Sens oleg a dob ag and Vadas one tween eng comeie 669
MIRSDICE EUCLPOSOM oc becas ss. .aice nest did ads codecarawslacdoed steeds Bas 670
III. The Sections and their Interpretation’ ............... cece ec ee ee ee eee 676
Section I. Western End, near Castle Farm .....................20. 676
MON eatictiber PAN 5. cacmecewctoep emt oeecadieeni anc iesess Salen 679
III. The Freestone Quarry near the Church ............... 679
IV. The Northern Main-road Quarry ....................- 680
Pi intr DPV VINA ei caakasc<,otceueanUptapesesee-sds 682
Wiz Vis, Vi =: Above ill Warm... 00.04 .daire ds, 683, 684
DURE WARE: Ae Wrap Mae a hase dg og on tun ie micidana wnt -a 684, 686
Tal ii ged laiigig 6-20) eget A ted a ne Shel ar a 689
WE se baris Bately Spinney: ills...) ale. ood casas te 689
IX., IX a. The Southern Main-road Quarry ............... 691
Ma dachledlopeh Harn soso scdsag cedayae cy ew ed -dvdevedan skeet 692
IV. The Development of the Dundry Strata ............ cece essence eee 695
rp NORM IGE nee cag a saeceene ae aeethione tas <scaren,sagt> deep 694
II. North-west by North to South-west by South ......... 696
LEL.< North-west)to South-east 22.2... 62 ...0c.cccseesebeocecseecdes 696
V. The Stratigraphical Sequence at Dundry Hill, with Table IV. ... 697
VI. The Faunal Sequence, with Tables V. & VA ........ cece ec ec ec ee eee 697
VII. The Correlation of the Dundry Strata with the Rocks of the
Cotteswold and Dorset-Somerset Areas; with Table VI. ...... 704
VIII. Remarks on the important Features of the Dundry Strata......... 705
mbes Marlstone; Rayek | 2.33. ce 2ica. ig diodes ised ice vealed & 705
Sere tip. Blue: Lronshot-beds <. 5..0).0<- case dvevcckenatesuAss cbsidivanienenes 706
fea te Digporbieria-Dede ¢ ve2e.. cece nen tbsnedes finseeasainasas oss 707
(4) The Strata of Aalenian Age ................2cscececeseees sre bration 708
(a) The Strata of Bajocian Age ...... irc lectctecceesccsses Bea TOG
(6) The Strata of Bathonian Age: .....00........ ccc ele ececesseecees 709
(7) The Geographical Extent of the Ironshot Oolite ............ 709
(8) The Geographical Extent of the Freestone ..................... 710
IX. The Bajocian Denudation, with a Section at Wellow ............... age
X. The Water-bearing Beds of Dundry Hill ................cccccceceeeee 713
XI. The Map of Dundry Hill, presented with this Paper ............... 714
(1) The Comparison of the Survey Map therewith ............... 718
(2) The Comparison of Sanders’s Map therewith .................. 718
SO A ita cicicalGvi vies nap « veka rts a me Sh Gia mnesdniedteuds os 719

I. IyrropvuctTion.

We must explain our title. It has been difficult to find a designa-
tion sufficiently terse and yet duly comprehensive. Had we spoken
of ‘ the Inferior Oolite of Dundry Hill’ we should have made use
of a term which is notoriously indefinite, has very different values
in different parts of the country, and even in its widest application

1 Dundry probably means ‘ wooded hill,’ ‘hill of trees,’ dr- or tr- being
the common Aryan base of words for a tree. But other etymologies are
possible :—thus the Welsh din dry means ‘forward hill” which would be a
a correct description of the relation of Dundry Hill to the Mendips.

222

670 MESSRS. S. 8, BUCKMAN AND E. wWILson _—{ Noy. 1896,

could have been given only toa portion of the strata that we intend
to describe. On the other hand, a title such as ‘ On certain Beds of
Dundry Hill’ would have been far too vague. The strata which
we have investigated form the upper portion—about the upper
100 feet—of that isolated, somewhat flat-topped eminence known
as Dundry Hill. They comprise deposits which would usually be
known as Marlstone, Upper Lias, Supra-liassic sands, and Inferior
Oolite. Owing apparently to a similarity in lithological structure
between the Marlstone rock-bed and a bed in the Inferior Oolite
itself, the whole of the above-mentioned deposits have been
mapped by the officers of the Geological Survey as Inferior Oolite
(75) around nearly the whole of Dundry Hull.

II. Hisrorrcat Rerrosprct.

Considering that Dundry Hill has always been known as a
classical locality for ‘Inferior Oolite’ fossils, that it is the most
westerly deposit of ‘ Inferior Oolite’ north of the Mendips, and
that it is within easy reach of a populous city, it must be confessed
that its strata have not received any great amount of attention—
especially for the purpose of making exact correlation of the deposits
with contemporaneous strata elsewhere. Nevertheless, if we were
to mention all those papers wherein more or less casual reference
has been made to the Dundry rocks, or to the fossils obtained
therefrom, it would be easy to make a somewhat lengthy biblio-
graphy; but such a compilation would be of little value. We
would, however, notice certain publications which have dealt with
the strata of this hill, in order to show what our predecessors have
accomplished.

Conybeare and Phillips’ noticed Dundry Hill, and referred to the
ironshot nature of the stone; while De la Beche* mentioned it,
but only in a general way, as a locality for Inferior Oolite. H. E.
Strickland? correlated the Oolite of Dundry with the Pisolite of
Cheltenham, the Cephalopod-bed at Haresfield Hill, and the Oolite
of Bridport.

In 1857 Lycett* shortly noticed Dundry and compared its beds
with those of the Cotteswolds. His remarks are of interest.
‘The ragstone’ [evidently the Coralline beds] ‘seems to belong to
the spinosa stage ; this is underlaid by useful building-freestones and
by sandy oolite .... which probably represent the Fimbria stage.’
‘The celebrated fossiliferous bed ’ [evidently the Ironshot Oolite] is
presumably correlated with the Cheltenham pisolite; the ‘ eynoce-
phala stage [Cotteswold Sands and Cephalopod-bed] is here repre-
sented by only half a yard of sands overlying the Upper Lias
Clay.’

1 «Geology of England and Wales,’ pt. i. (1822) p. 236.

2 «Report on the Geology of Cornwall, Devon, and West Somerset,’ London,
1839, p. 234.

3 Quart. Journ. Geol. Soc. vol. vi. (1850) p. 249.
“ «The Cotteswold Hills, London and Stroud, 1857, p. 72.

Vol. 52. | ON THE UPPER PORTION OF DUNDRY HILL, 671

The correlation of the ragstone and its position above the building-
stone are practically all that we agree with in this comparison
(see Table VI., facing p. 704).

In 1859 Wright’! gave an account of the Inferior Oolite, and in
his paper published certain ‘ Notes on Dundry Hill, by R. Etheridge’
(op. cit. p. 21) This communication is practically a subsidiary paper
by the latter author, and the chief matter of interest in it is the
sequence of the strata, which was given in the following terms :—

Feet.

7. Building-stone or Freestone beds .%....... 12
Gs Bime-erained! GOlite) io. ih. fl et slice ene 4
5. Ragstones (shells) ....00ccssss-cevececsosecssnes 8
3 & 4. Rubbly Limestones (shells) ............ 12
2 ATMAODIGO-DOG.. os ig aysrncsnacssheavagcecuns« 5
b. Ironshot sltelly: bed) s...0:0<..s<ten: soqs5 =

ee Upper Dias Sands.ei Je Riwe Oe ocd e be chee 2
Mey Maawrety hilasina pes eth e odes. Moke te 500

We would notice, in regard to this section, the following points :—

1. That no Middle Lias is mentioned, and on this subject Mr.
Etheridge is very emphatic, saying (p. 22), ‘In this fine develop-
ment there are no traces whatever of the Middle Lias or Marlstone
as exhibited in the Bath district, and in the Cotteswold Range
generally.’ (The italics are his.)

2. The Upper Lias sands are stated to be 2 feet in thickness ;
‘they pass downwards into the clays and shales of the Lias
beneath.’ They are said to underlie a shelly bed which, together
with the Ammonite-bed, is 5 feet in thickness. From the list of
fossils given it would seem that the ‘ Ammonite-bed’ is what we
shall presently call ‘ the Ironshot Oolite’; but we are quite unaware
of any sands within 5 feet of this bed; and in fact we have failed to
find any truly sandy strata anywhere in the Dundry range. About
the position indicated, and particularly at the western end of the hill
—the locality mentioned by the author,—we find sandy limestone
and marl, and this is probably the horizon referred to ‘ Upper Lias
Sands’ by Mr. Etheridge ; but these strata yield Terebratula Hudesi,
Oppel, and 7’. cortonensis, 8. Buckman, indicative of a much later
date. (See Table V., p. 699.)

In regard to the other beds we would make the following remarks,
taking them in order :—

‘No. 1. From the description given this is evidently the series
of beds at the base of what we call ‘the Ironshot Oolite’; but it
is said to lie ‘immediately upon the zone of semi-indurated sands.’
In the list of fossils given are Cirrus Leachi and C. nodosus, which
would be found in strata occupying such a position directly above
the sands ; but they are not to be obtained from the beds imme-
diately below the Ironshot. The explanation is that two beds at
different horizons have been confounded—one, the basement-bed at
Rackledown, the other, the infra-ironshot bed in the northern road-

1 *On the Subdivisions of the Inferior Oolite in the South of England,
etc. Quart. Journ. Geol, Soc. vol. xvi. (1860) pp. 5-48.

672 MESSRS. 8. 8. BUCKMAN AND E, witson __ [ Nov. 1896,

side quarry. ‘The mistake, so far as the latter is concerned, has arisen
as the natural consequence of considering the before-mentioned marls _
with Terebratula Eudesi as ‘the Upper ‘Tiss Sands.’

‘No. 2.—The Ammonite-bed.’. This, as we said abouenl iS
evidently what we call ‘ the Ironshot Oolite.’

‘No. 3.’ The ammonites quoted as coming from Nos. 3 and 4
(p. 24) puzzle us entirely, because they are species which we have
found beneath and do not find above ‘ the Ammonite-bed ’ eon
shot Oolite).

‘No. 5.—The Ragstones of Dundry forming the zone of Ammo-
nites Parkinsoni.’ There is evidently some confusion here. The
description and the fossils given answer partly to what we call
‘the Coralline beds,’ and partly to our ‘ Terebratula Hudesi-beds.’
The locality where the beds are said to occur—to the west of the
church—shows only Terebratula EHudesi-beds, and no Coralline beds:
the locality referred to is obviously Clements’ Yard (see p. 679).
Further, ammonites are quoted in No. 5; but practically we have
found none in ‘the Coralline beds, nor in the strata above ‘ the
Tronshot Oolite.? The beds (No. 5) are placed by Mr. Etheridge
below the Freestone and above the Ironshot; but the Coralline
beds come above the Freestone, and the Terebratula Hudesi-beds
are below the Ironshot.

‘Nos. 6 & 7.—The Building-stone.” This is said to be the
highest set of beds at Dundry; but we find them to be covered
by several feet of Coralline Limestone.

We have thus criticized this paper because Wright, in intro-
ducing it, said that ‘ the true relations of its [Dundry Hill] beds of
Inferior Oolite with those of other regions have not, until now,
been accurately described ;’ and also because it is actually the only
detailed communication on the geology of Dundry Hill which has
appeared in the pages of the Quarterly Journal. . Unfortunately, by
our researches we are unable to confirm the Dundry sequence of
strata in the manner presented to us by the author, but we can
understand the order given by him on a supposition of some con-
fusion of beds at different levels in various isolated exposures
which may not have presented an overlapping series.

In 1875 EK. B. Tawney? noticed Dundry and Mr. Etheridge’s
communication thereon, observing that the succession of beds as
given by the author cited is open to some doubt, and that ‘ above
these [the Ragstones] Mr. Etheridge places the Building stones,
while others have placed them below the Ragstones.’ On his own
part Tawney remarks that ‘A. Whirchitone, Sowerbyt, and Huwm-
phriesianus seem to occur together.’

James Buckman ? considered that the beds at Dundry and at Brad-
ford [Abbas] were on the same horizon, and that they had not the
slightest connexion with the Cephalopod-bed of Gloucestershire,
thus correcting some earlier authors.

} “Bristol and its Environs.’ Published under sanction of local Executive

Committee of Brit. Assoe, 1875.—‘ Inferior Oolite,’ by H. B. pea p. 378.
2 Quart. Journ. Geol. Soe. vol. xxxiii. (1877) p. Ny

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 673

W. W. Stoddart’ compared Dundry Hill to an island, pre-
sumably in the Jurassic sea! He gives a diagrammatic section of
the strata of the whole hill in the forefront of his paper; but it is
only with the beds referred to in the upper portion of this section
that we are concerned. This portion sets forth the construction of
Dundry Hill in the following terms :—

Feet. Inches.

Parkinsoni. {1:, Freestone .............00.0- 16 9
About 23 feet. | 2. Ragstone ..............00+ 6 0
Lr SLC 5/59 1a i Rs tate 1 0

Pi EPUST tact ae rica te 1 6

Humphriesianus. } 5. Brachiopoda ............... 4 8
bout 20 fect. 1G. Conghifera s ...ccccc-4 Se
| 7. Cephalopoda ........ = ee 3 0

\8 Prone hOtiac coanes «onsets vse 2 0

Midford Sands ............ 2 0

10. Upper inma? 1. wicca 4 0

Lie (Middle Liter te. cii cs. ak 1 0

It will be noticed that Stoddart does give Middle Lias as being
present in this section ; but in the text the evidence quoted entirely
destroys the value of the assertion.. ‘A bluish marly limestone
about a foot in thickness and corresponding to the marletone .
so full of the shells of Am. thouarsensis, A. radians, and A. ieee
that the presence of the Middle Lias is fully justified’ (p. 284).
There is obviously a mistake here; these are ammonites of what
Oppel called the ‘ Lias- oolith Grenzschichten’—the Cotteswold
Cephalopod-bed equivalent,—and they have never been found in
Middle Lias.

It is easy to see that Stoddart’s 7, 8, 9 correspond to Etheridge’s
2, 1,a; and therefore the remarks which we made concerning the
one apply equally to the other. We confess that the section above
the No.7 bed puzzles us. It is true that there are brachiopoda and
conchifera in the strata superior to the bed which we suppose No. 7 to
denote—namely the hard Ammonitiferous Ironshot,—but certainly
not in such numbers as to attract the attention that seems to have
been given to them here ; whereas there are beds underlying ‘the
Ironshot’ (see Table IV., facing p. 696) to which the description
applies very well: they are noticeable for the abundance of fossils
of the orders named. We can explain the sequence observed by
Stoddart only in the manner which we suggested with regard to
Mr. Etheridge’s paper, or else on the supposition that Stoddart
accidentally reversed a part of his section.

In 1878 Mr. J. F. Walker * compared the brachiopoda of Dundry
with those of Dorset and the Cheltenham district, pointing out that
certain species were common to Dundry and Dorset, and were not
found in the Cheltenham district, which has its own peculiar forms.
He suggested that a Paleozoic barrier might have separated the
Dorset and Cheltenham areas.

1 “Geology of the Bristol Coalfield. Part 5. Jurassic Strata.’ Proc. Bristol
Nat. Soe. n. ser. vol. ii. pt. iii. (1879) p. 279.
2 * Terebratula Morieri in England,’ Geol. Mag. 1878, p. 552.

674 MESSRS. S. 8. BUCKMAN AND E. WILSON _[ Noy. 1896,

In his interesting survey of the Inferior Oolite rocks Mr. W. H.
Hudleston} dismisses the Dundry sections in a few words. He
says: ‘In the present condition of the available exposures it is by
no means easy to construct an intelligible sect?on of the Inferior
Oolite in this remarkable hill.? The author, however, makes an
important observation as to the affinities of the Dundry beds (p. 24).
‘Both the facies and lithology of those fossiliferous beds recall
some of the most typical of the Dorsetshire sections, in spite of
their lying well to the north of the Mendips. But, on the other
hand, the large development of coral in the Parkinsoni-zone quite
distinguishes this remarkable outlier, which topographically must
be included within the second [Cotteswold] district, unless we are
to regard it as sufficiently important to constitute a region by

itself,’

In 1889, one of us (S. 8. Buckman),? following somewhat on
Mr. Walker’s suggestion, compared both the brachiopods and the
ammonites of Dundry, Dorset, and the Cotteswolds. He came to
the conclusion that Dundry was more truly an outlier of the Dorset
district than of the Cotteswolds. He theorized as to the manner in
which Dundry, during an interval of Jurassic history, might have
been cut off from the Cotteswold area. This separation of the
areas he supposes might have been brought about by a renewed
elevation of Paleozoic rocks during later Liassic time—such
elevation being along the lines of the Mendip axis and of the
Tortworth barrier; and he considers that the result of such
elevations would naturally have been to bring the recently-deposited
Jurassic rocks of the affected areas sufficiently above sea-level to
form barriers cutting off the Dundry area from communication
with the Cotteswolds, and the Cotteswolds from Dorset; but that, as
the Dundry strata and their contents are so similar to the Dorset
rocks, some direct remains of communication existed between these
particular areas; and it was suggested that such communication
had been effected around the western end of the Mendip range.

In the early part of 1892 the same writer® gave an abridged
section of part of the Inferior Oolite of Dundry. He noticed ‘ the
Tronshot,’ ‘the White Bed below the Ironshot,’ and ‘the Nodular
Bed,’ assigning the two former to the Sauzez-zone, and the latter to
the concavum-zone. He further correlated ‘the White Bed below the
Tronshot’ with the Sauzei-bed of Oborne (Dorset); but in regard
to the exact correlation of ‘the Ironshot’ itself he was in some
uncertainty.

In 1893, as one result of the work done by us for the present
paper, S. S. Buckman * gave an outline-section of the upper part of

ne Gasteropoda of the Inferior Oolite,’ Pal. Soc. vol. xl. p. 56, issued for

2 «The Relations of Dundry with the Dorset-Somerset and Cotteswold
Areas during part of the Jurassic Period,’ Proc. Cotteswold Nat. F. Club, vol. ix.
pt. iv. 1889, p. 374.

3 «JTnferior Oolite Ammonites,’ Pal. Soc. vol. xlv. p. 293, issued for 1891.

4 «The Bajocian of the Sherborne District,’ Quart. Journ. Geol. Soc. vol. xlix.
(1893) p. 508.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 675

Dundry Hill, to correlate its beds with Dorset. He then recognized
that strata were deposited at Dundry during the Sauzei, Witchellie,
discite, and concavi hemerz, and that ‘the Ironshot Oolite,’ in a
restricted sense, was laid down during the first-named hemera—the
latest in point of time. He corrects the supposition that the ‘ Iron-
shot’ was contemporaneous with the ‘ Ironshot’ of Sherborne; and
notes the absence of any strata deposited during the Humphriesiant
and niortensis hemere.

In 1894 H. B. Woodward furnished a short account of the
Dundry beds in his Survey memoir,’ but he made only the following
divisions :—

Building or Freestone Beds. Zone of Ammonites Parkinson.

Ragstones.
Tronshot Limestones. Zones of Amm. Humphriesianus
Midford Sands. and Murchisone.

No attempt is made to separate the Ironshot limestones, or to
distinguish the fossils of the ‘ Humphriesianus’ and ‘ Murchison’
zones.

We have given this short summary of the most important notices
which have been published concerning the Dundry beds, in order to
show what has been accomplished in the interpretation of its
deposits. It now remains for us to give an account of our own
work.

Our first joint visit to Dundry Hill was made in the autumn of
1887, when our observations showed the desirability of a more
detailed account and more accurate correlation of the Dundry
strata. Since then we have, together or separately, paid many visits
to the hill; we have resided there at different times, and, when
we found that the geological structure of certain parts of the hill
could not be discovered in any other way, we employed quarrymen
to make special excavations. We owe our best thanks to Sir
Greville Smyth, Bart., and to J. H. Shorland, Esq., for their
courteous permission to make the necessary excavations upon
their property ; and we are also indebted to their tenants for kind
assistance in this matter. Had it not been for these excavations
and the information thus obtained, our work would have been very
imperfect. Even now it is far from having that completeness
which we would desire; and, before such completeness can be
obtained, very much more in the way of excavation will have to
be done. However, the results which we have obtained are, we
hope, of sufficient value to justify the placing of the present com-
munication before the Society.

1 Mem. Geol. Surv. ‘The Lower Oolitic Rocks of England,’ in ‘ The Jurassic
Rocks of Britain,’ vol. iv, (1894) p. 99.

676 MESSRS. S, 8. BUCKMAN AND E, witson ___[ Nov. 1896,/

Til. Tus Srcrions anp THEIR INTERPRETATION.

The sections to be described are taken in the following order:
first, from west to east as nearly as may be; secondly, from
Dundry church in a direction south-east by south; thirdly, from
the church ina south-easterly traverse.

The first section to be noticed is situated towards the north-
western corner of the hill in the road-cutting leading from just
west of ‘The Grove’ to Castle Farm. This section shows only a
few feet of rocks, mostly belonging to the hemeree Sonninie-discitee *
capped directly by ‘top beds.’ Most of the other details are the
result of special excavations.”

Section I.— Western End, near Castle Farm.

ft. ims. “att. "mas:

—

. Thin-bedded, grey, compact lime-
stones, apparently unfossilife-
rous, extending upwards.
. Pale grey lumestone = 25.2.4. 07.22) | ereane 0 4
. Soft, brown, ironshot limestone,
with derived nodular lumps of a
dense limestone. Astarte Man-
seli, Buck., common ; <Ancylo-
ceras, fragment; Montlivaltia... ...... 0 5
SONNINTA. 4, Planed-off..top on some blocks.
Yellowish-grey limestone, hard
and well ironshot. Lima EHthe-
ridgu ; Lithodomi at top......... 0 6
5. Yellowish-grey ironshot limestone
harder than the bed below, with
TOW ERA MUMTOMUCES! J) get eaedt en tee 0 3
6. Whitish ironshot limestone, very
small iron grains. Ammoniti-
ferous bed. Waétchellia, nume-
rous new species; Stephano-
ceras, various species ; ‘ Stephan,’
cf. Sauzei, Sonninia cf. fissilobata
AbsphepboO poms (540.06: cateeasuate One
. Hard, greyish, sparry ironshot
limestone; often has a brown
tinge. Perished ammonites of

Co bo

GARANTIANA.®

1

the fissilobata-type ..........2 00 One
8. Brown sandy parting. Large Son-
MUM CL OUQNIS oi venisnivaiie «nese eee Oi
—- ae
DisciTs. 9. Grey, crystalline, massive lime-
stone; very small and diffused
MOM OVALS paps d daowisls aise xyee Seay 0 5

1 See Table IV., facing p. 696, for the interpretation of these and other terms.

? [Since this was written a considerable amount of quarrying has been done
here, so that the section is greatly improved.. We have been able to add a few
details in consequence.—Aug. 31st, 1896. ]

3 The amount deposited during the times of the respective hemere is
shown by the hemeral names at the left hand, marking the last deposit of
the date to which they belong.

Vol. 52.]

Discit# (cont.).

Concavl.

BRADFORDENSIS

MURCHISON.

OPALINI.

AALENSIS.

DuMoRTIERIA,

DISPANSI.

ON THE UPPER PORTION OF DUNDRY HILL.

13.

1.

25.

26.

27.

Secrion I. (continued).

Brought forward scsi .caicecsto op

. Yellow mar! parting, irregular’...

re

Grey crystalline limestone in large
blocks. Lioceras aff. interme-
dium, Hyperlioceras, Belemnites
Blainvillet, Sonninie,spinousand
costate species—one aff. S, cos-
tata, both in rotten condition.
Astarte excavata,Lima Etheridgit

. Laminated grey limestone, with

ochreous clay streaks '............

Light-grey crystalline limestone.
Lnoceras intermedium, Hyperlio-
ceras aff. discites, Rhynchonella
Forbesi, and belemnites .........

Soft, greyish, earthy limestone with
fragments of whorls of a Son-
ninia of the marginata-type,
and imprints of (presumably)
THOCETAS CONCAVUM, | ....20eeeceeees

. Irregular marl parting ............
. Light-grey sandy limestone in two

blocks, with brown earthy marl.

Terebratula Hudesi, T,. corton-

ensis, and T. perovalis .........008

SOUR AMEN 00. con ak cee sean jennesns
. Light grey, nodular, sandy lime-

stone and clay infillings between
fhe loess.) Le saan) cd gewyaeenas>s

. Light-grey nodular limestone and

clay infillings. Zeilleria anglica
(Oppel) in the limestone .......

. Do. more sandy ; no fossils seen ...
. Light grey earthy limestone. Tere-

bratula Eudesi, Trigonia striata,
Lnoceras cf. bradfordense .........

. Olay parting. Z. anglica............
. Grey, earthy limestone, somewhat

coarsely. ironshot ......,...4.+0s00

. Do.more coarsely ironshot. Large

Lima aff. Etheridgii. Scattered
black phosphatic concretions in
the lower 6 inchés ...............
Blue, compact, argillaceous lime-
stone. Grammoceras subcomp-
tum; numerous lamellibranchs
and gasteropods indeterminable ;
casts of Cuculleasp., Inoceramus,
MUMDEPIEYA BD: sanvaqya-supavaveodas
Greenish-blue clay, measured by
the level and reckoned to be inail

Excavation made lower down the
hill by the roadside :—

Pinkish to grey. dense, earthy lime-
stone—a few large iron specks.
Grammoceras fallaciosum.........

0 2
O.7
0 2
neg
0 5
1 0
78
12
0 1
Ot
ited to ie alegs:
1 0
BO
0 6
01
19
baat Bahay
rns 1
yz”. 0
bes: 50
ee 0

+ These clay streaks are impersistent, and occur at various levels.

6

6

678 MESSRS, 8. 8S. BUCKMAN AND E, WILSON [Nov. 1896,

Secrion I. (continued).
ft. ins. " fipmss

STRIATULI. 28. Greenish-grey, earthy limestone,

coarsely ironshot. G. striatudum.

Pectens, belemnites ...............0 « oes 0 2
BIFRONTIS. 29. Blue, argillaceous limestone, irre-

gularly speckled with large iron

grains. Hildoceras bifrons, be-

lemnites. Ehynchonella sp. ... ...+0 O72
FALcIFEeRrti. 30. Pinkish argillaceous limestone,

very few iron grains. Harpo-

ceras falciferum, Dactylioceras

COMMUNE Meat tees Pate eeRcccics | Sanane 2
ay eee © 81. Greenish-blue clay visible ......... 0.2... 7 0

Beginning at the base, the first point to notice is the absence of
the marlstone—a fact also further confirmed for the western part
of the hill by excavations at Elwell Spring giving the same result.
As will be seen in later sections, the marlstone is found in places
interposed between beds 30, 31.

Next, the thin deposits (Nos. 27-30), yielding the same species of
ammonites as the base of the ‘ Cephalopod-bed’ of the Cotteswold
range plus ‘ Upper Lias,’ are important; and then the thick mass
of clay (No. 26) proved at the other end of the hill to have been ~
deposited during the Dumortierie hemera, contemporaneously with
the middle part of the Cotteswold Cephalopod-bed. All these
deposits show a thickness of about 50 feet, which would have been
formerly called ‘ Midford Sands and Upper Lias ’—a marked differ-
ence from the results given by Etheridge and Stoddart (see pp. 671,
673).

The evidence concerning the deposits made during the bradford-
ensis and Murchisone hemere is not very satisfactory here; and it
could hardly be so without excavations made on a much more
costly scale than we were able to undertake. Zedlleria anglica,'
however (see Nos. 19 & 22), marks a very definite horizon in
Dorset*; it lived more or less contemporaneously with Ludwigia
Murchisone, and perhaps died out just before Lioceras bradfordense ;
but on this point further evidence would be desirable.

Above the horizon of Zeillerta anglica, the next noticeable datum-
line is that of Bed 8 with Sonninia aff. ovalis, Quenstedt. Between
these two horizons are certain beds with species of Hyperlioceras in
the upper part and species of the concavum-type lower down.°

Lastly, it is to be noted that the planed-off top, indicating denu-
dation, appears on a bed which we assign by its ammonites to the
deposit that we shall hereafter call the Lower White Ironshot,
consequently there is a distinct non-sequence between Beds 4 and 3,
which is partly filled by some strata met with in sections to be
described presently.

1 See note, p. 702.

2 See ‘The Bajocian of the Sherborne District,’ Quart. Journ. Geol. Soc.

vol. xlix. (1893) p. 489.
3 The Foraker areas of Hyperlioceras and of the concavum-type of ammonite

leave distinct impressions, the former bitabulate JL , the latter fastigate A.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 679

The next section to be noticed is that at Clements’ Yard, near
the church. Bed 3 in this section is the equivalent of Beds 4-8 of
the Western-end Section ; and it is also capped directly by strata of
the Garantiane hemera.

Secrton II.—Clements’ Yard, on the right-hand side of the road
from the Church to ‘ The Grove.

ft. ins. ft. ins.
GARANTIANA. 1. Light-grey stone with Acanthothyris
SPUNOSO <i an-sansss- exposed about 0 10
2. Rubbly marly limestone, slightly
ironshot. dstarte Manseli ...... 0 2
—- 19
Sonniniez. 3. Whitish ironshot __ limestone.

Witchelie numerous; Sonninie,

S. ef. fissilobata at the bottom ... 1 6
4. Pinkish limestone. Sonninie of the
ovalis type; abdomen showing... O 6
5. Irregular ochreous marly parting... O 1
ay
Discira. 6. Light-grey, slightly ironshot lime-

stone, with earthy and ochreous
partings (horizontal and vertical).
Terebratula Kudesi, T.cortonensis,
T. perovalis, belemmites ..........2. sesecsees 1 10

The beds above the topmost deposit at Clements’ Yard are found
in the Freestone Quarry, near the Church, of which the following
is the section :—

Section III.—The Freestone Quarry near the Church.
(Mr. Towle’s Quarry.)
ft. ins. ft. ins,

CoraLuine Beps. 1. White limestone in one thick
bed—a crystalline rock of open

texture, conspicuous from beds

below on account of its greater

resistance. Corals, echinid

spines, polyzoa. This bed caps

the quarry in certain places... 1 6
. Thin-bedded, whitish ragstones

with grey streaks along centres,

in beds 2 or 3 inches thick or a

little more. mixed with marl.

Zeilleria Waltoni, Terebratula

GUGGACE, GOVAIB « « Soene davapon yoann 6 0

to

Tne Freestone 3. Pale-grey, white, or yellow lime-
Beps. stone, about 9 inches thick,
passing downward without any
hard-and-fast line into massive,
compact, light-yellow ragstone. 5 9
. Compact pale freestune, the most
valuable bed of Dundry stone,
somewhat variable in thick-

aN

Sonninre. 5. Light stone with Witchellie ex-
posed in a fissure of the quarry.
(Now filled up—1895.)

680 MESSRS. 8. S. BUCKMAN AND E. WILSON _—[ Nov. 1896,

Bed 5 of this section is the same as that numbered 3 in the
Clements’ Yard exposure. Between it and the Freestone there is
very probably some representative of Beds 1 & 2 of Clements’
Yard; the inaccessibility of the fissure prevented accurate deter-
mination in this matter.. But the point to be noticed is that the
beds of the Sonninie hemera are not capped by any representative
of the Ironshot Oolite, either here or at Clements’ Yard.

The thick freestone-beds Nos. 3 & 4, especially the latter, yield a
stone of considerable economic importance; they are capped by
a few feet of coralliferous stone and marl which we have termed
the ‘ Coralline Beds.’ Several species of corals have been obtained
from these deposits, as well as many specimens of Zeillerta Waltona,
and, less plentifully, Aulacothyris carinata, Rhynchonella plicatella,
th, subtetraedra ; and from the same bed elsewhere Acanthothyris
panacanthina rarely. These brachiopods seem to indicate that the
Coralline Beds were contemporaneous with the ‘top beds’ of Broad
Windsor, yielding ‘ Stephanoceras zigzag.’ If that beso, the Dundry
freestone would be equivalent to the ‘Fossrz Brep’ of Halfway
House, Dorset, which yields Strigoceras Truellit and Parkinsonia
dorsetensis, in which case the date of the deposition of the Freestone
would be Zruwellic hemera.*

The next section is one of the best known at Dundry ; it is on
the eastern side of the main road, on the northern flank of the hill,
not far from the ‘ Butchers’ Arms.’ :

Section 1V.—The Northern Main-road Quarry, near the

‘ Butchers’ Arms,’
ft. ins. ft. ins.
CoRALLINE 1. Rubbleand soil, ...c2-.5 se. DOUG: Mes. .oeace 3.0

BeEps. 2. Grey, crystalline, lenticularly-bed-
ded, coralline limestone. Many

COPALS og nnd eects ricesbs asset psi 2/6
3. Greenish clay with dark crystalline
limestone. Zeilleria Waltoni,
Terebratula sp. nov., Acantho-
thyris panacanthina, and a num-

ber of micro-brachiopoda ......... 7)

EQUIVALENT 4, Whitish, regularly and _ thinly-
or Dunpry bedded, compact limestones with
FREESTONE. small iron specks. (The top bed
ROT Bo shan ols vio auiote Rie Seg eeeeee 4 0
SAUZEI. 5. Yeliowish-brown . ironshot _lime-
stone—the well-known fossili-
ferous horizon. ‘ Stephanoceras’
Sauzei, Sonninia Sowerbyi, 8.
corrugata; many ‘mammillate’
_Sonninie ; Stephanocerata of the
Bayleanum-type ; Acanthothyris
paucispina; Terebratula sp.; nu-
merous lamellibranchs, such as

1 See ‘The Bajocian of the Sherborne District, Quart. Journ. Geol. Soe.
vol. xlix. (1893) p. 487.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 681

Sszcrrion LV. (continued).

ft. ins. ft. ins.
Savzet (cont.). Astarte multicostata, Ctenostreon
pectiniforme, Ostrea explanata,
Myacites jurassi, Cucullea ob-
longa; and many gasteropoda,
e. g. Pleurotomaria elongata, Pl.
ornata, Pl. granulata, Pl. sulcata,
Pl. paucistriata, Trochus Zetes,
Ataphrus levigatus, & Cerithium
subscalariforme. (The top flat
and: planed off.) ..2.....css.ccseoesee
Wircuetitiz. 6. Whitish, argillaceous, ironshot lime-
: stone; when wet, soft and much
broken up; the upper 2 or 3
inches more compact and gene-
rally adherent to the base of the
Ironshot. Many lamellibranchs
and ammonites ; the horizon for
numerous Witchellig, especially
involute, costate forms ; eiion.
cha crassa, Opis similis, Astarte
excavata, A. elegans, Plewroto-
maria oxytera, Pl.armata ...... 0 5
De RSCOMM TMA pl epeecanieweh sapadeasivet 0 2

8. Brownish-grey ironshot limestone.

Belemnites, bivalves, and uni-
WOUNESED satcerectussenuennotaorers tian OF

SonnIn1z. 9. Grey ironshot limestone, with many
Sonninie and Witchellie ......... 0 8

10. Brownish-yellow shelly limestone,

very much speckled with small

iron grains; at the top of this

' comes often a bed of brownish

sand ‘about 3 inches thick, with

numerous more or less perished

Sonninie of the ovalis-ty pe, mark-

ing a conspicuous horizon in the

SPURONY, soenr's c chase aware aaenedscsec 0 9

DisciTz. 11. Yellowish-brown limestone with
compact ochreous marl. Umbi-
licate Hyperlioceras, Terebratula
Eudesi, and T. cortonensis ...... Pa
12. Yellowish-brown limestone with
small ochreous specks. Terebra-
CULe HUES Y..diccsUedviwsadecvedes- Qed
18. Light-coloured limestone, pale grey
below, yellow-ochreous and marly
BUMOVEDS) 00 Re preds leat eos. £0

14, Light-grey limestone with small
ochreous specks. (Below present
floor of quarry—1895.)

The correlation of this section with those previously given may
be commenced at the horizon of Sonninia fissilobata-ovalis (bed 10),
which is well marked. Below that horizon the rocks are seldom
exposed, but we are able to record the beds (Nos. 11-14) with

682 MESSRS. S. 8. BUCKMAN AND E, witson __[ Nov. 1896,

Hyperlioceras and Terebratula Hudesi, similar to beds of the same
date at the Western-end Section (p. 676).

The most noticeable features in this section are beds Nos. 6-8,
yielding a fine series of Wotchelliw, and the overlying Ironshot
Oolite, yielding Sonninie of the propinquans-type, with ‘ Stepha-
noceras’ Sauzeit. These beds are wanting from the sections previ-
ously described ; but in this part of the hill they have escaped ‘ The
Bajocian denudation.’* Still, there is a non-sequence between
Beds 5 and 4, and this gap is not filled by any strata shown in
any of the sections at Dundry. In order to make the sequence
complete, strata laid down during the niortensis-Humphriesiant
hemerz should be present.”

Another interesting fact—and one of economic importance—
about this section is the great attenuation, together with change in
character, of the deposit contemporaneous with the freestone of the
quarry near the church. The freestone deposit is only represented
at this Northern Main-road quarry by Bed 4, consisting of some
thin-bedded limestones about 4 feet in thickness. The decrease
will be best appreciated by consulting the plotted diagram, p. 695.

Still proceeding in an easterly direction, the next exposure is
found near East Dundry, where the Ironshot Oolite crops out on
the hillside west of the village, but only the following very general
details have been obtained :—

Section V.—Hast Dundry Village.

1. The ‘upper beds’ crop out by
the roadside in the village.

SAUZEI. 2. ‘The Ironshot Oolite.’ These rocks crop out
WITCHELLIZ. 3. The Upper White Ironshot. in the bank near a
Sonniniai. 4. The Lower White Ironshot. rough path.

(Discitx To 5. The lower stone beds. (See

view. Estimated thick-
ness :— ft. ins,

These are hidden from
15 O

AALENSIS.) general section, Table IV.,
facing p. 696.)

DumortiznizZ. 6. Dumortieria-beds :—Stiff clays with grey \
sandstone-bands by ‘the Rookery’ and
above ‘Spring Farm.’

(DIsPANsI TO 7. An isolated block of the bifrons-beds—a
BirrRontis.) pinkish stone, coarsely ironshot. Har-+ 55 O
FALcirEri. poceras Sp.
8. Yellowish clay.
9. Pinkish-grey earthy stone. Pseudolioceras
sp. 9 inches.
Spinatr AnD _—10. Strongly ironshot, somewhat variable, mas-

? MarGaARITATI. sive stone-block, with belemnites, Psewdo-
pecten equivalvis, Terebratula punctata,
and Ostrea in the lowermost 2 feet ......... 5 6

Note.—The Marlstone, where it crops out on the opposite side of the valley,
contains Amaltheus margaritatus and Rhynchonella tetraedra.

There are three ironshot beds at different, horizons—Nos. 2, 7, and 10,—but
they are all very different, both in lithological characters and in the fossils which
they contain. This is a matter of some importance. ,

1 See p. 711.
2 See ‘The Bajocian of the Sherborne District, Quart. Journ. Geol. Soc.

vol. xlix. (1893) p. 500, section of Frogden Quarry.

i]

es | a ee

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 683

The Marlstone Rock crops out in the bank of Spring Farm rick-
yard, in the middle of East Dundry, and as it forms a small feature
it may be traced along the valley below the exposure of the Iron-
shot Oolite. A measure with the level yielded 70 feet, separating
these two well-defined rocks. Deducting from this 15 feet, which
other sections in the neighbourhood indicate to be the thickness of
the stone beds below the Ironshot Oolite, 55 feet are left as the
thickness of the Dumortieria-clays, and the presumed intervening
stone bed (that is, the ‘ bifrons-bed’). (See this section, Bed 7, and
Section I., Beds 27-30.)

A point of very considerable importance is the above-mentioned
outcrop of the Marlstone Rock. It is evident that the officers of the
Geological Survey mistook this rock, which is an ironshot oolite, for
‘the Ironshot’ (No. 2)—a bed so noticeable in the last section—
whereby they confused the bottom bed of this Section V. with the
top, which is 70 feet above it. hen, acting on this supposition,
and knowing there would be so much of the ‘ Inferior Oolite’ below
the ‘Ironshot,’ they drew the base-line of the ‘Inferior Oolite’
somewhat below the outcrop of the Marlstone Rock, with this result
—that they have coloured in their map as ‘ Inferior Oolite’ not only
areas occupied by what they call ‘ Midford Sands’ or ‘ Upper Lias’
in other districts, not only Middle Lias, but even in all likelihood
a part of what they would term Lower Lias. And in this way they
have made the Inferior Oolite in places—for these remarks apply to
most of the hill—nearly 150 feet thick: that is, from where they draw
their line up to the top of the hill. The ‘Inferior Oolite’ base-line
should have been drawn at the base of No. 5, about 15 feet below
the highest outcrop of the Ironshot Oolite ; whereas it is drawn in
the Geological Survey maps some distance below the outcrop of
Bed 10—in fact, nearly 100 feet too low down.

Going farther east, we notice on the northern escarpment of the
hill above Hill Farm certain exposures of the Marlstone and asso-
ciated beds giving the following results :—

Secrion VI.— Above Hill Farm (A).

ft. ins. ft. ins,

VariaBILis, 1. Pale drab stone. Rhynchonella aff.
MITE) obo ccc leas a gei'e dunsoasemaneuent 7 4

2. Purplish argillaceous ironshot stone.
Belemnites; Zeilleria aff. Lycetti ... O 6

3. Dense blue rock, derived. Hildoceras

bifrons; lumps of a pinkish stone,
ochreous. Belemnites abound ...... 0 3

5 ree |
SpPINATI. MIEN ONG TOGG cet cperrchguucwuctins, -oeieiacsae 2 0

In this section a deposit laid down during the variabilis hemera,
containing derived fossils of the bifrontis hemera, rests directly upon
the Marlstone. In the next section, obtained from tumbled blocks
on the hillside, it does not.

Q.J.G.8. No. 208. 34

684 MESSRS. S. 8, BUCKMAN AND E. witson _[Nov. 1896,

Section VI a.—Above Hill Farm (B).
(The point almost immediately south.)

ft. ins. ft. ims.
VariaBitis. 1. Lower Rhynchonella-bed, or next bed
below. Pale drab to purplish-brown
stone, with few scattered iron grains.
Belemnites and PA. aff. Moore? ......0 ...s.0ee. 1. a
Brrrontis. 2. Yellowish-drab to purplish-brown stone
with many scattered coarse iron

grains. Ammonites and belemnites. ......... 0 8
Farcirert. 3. Dense pink stone, small belemnites ... O 2
4. Dense purplish-grey stone ............... 0 1
sees 0 3
SPINATI. 5. Marlstone Rock. Yellowish - brown,

crystalline, richly oolitic rock, with
Pseudopecten equivalvis, a large
Gryphea or Ostrea, and large belem-
MICES PAELLA, ese dooce the ott tenance hE ee eee 1 bg
The next section, taken from slightly shifted blocks on the hill-
side, gives the following details concerning the Marlstone.

Section VI s.—Above Hill Farm (C).

ins.
SPINATI. 1. Marlstone Rock. Massive ironshot; Belemnites,
Gryphea, Ostrea, Pseudopecten equivalvis...... 2 9
Marearitati? 2. Dull; brownish, laminated, but massive, quite
unfossiliferous sandstone .............cececeeseeeees 1

There are no sections open at Maes* Knoll, and it was necessary
to make excavations at suitable places. The next section shows
one made on the western flank of the hill or promontory.

Szction VII.—Maes Knoll (the eastern end of Dundry Hill).
The western side, gust south of the Tump.

ft. ins. ft. ins.
A gentle grass-covered slope from the
top of the hull, concealing rock .._......)).:-.snes 6) 0
GaranTianz. 1. Yellowish limestone thickly speckled
with iron grains. Limatula gibbosa,
Acanthothyris spinosa, Montlivaltia
WOODS ites Naras oleeine Ores sos civ'oat «ee CEE 1 4
2. Pale grey, crystalline limestone with
numerous, but irregularly distributed,
large, subangular iron grains, and
with small lumps of a bluish - grey
sandstone nearly at the top. There
are also in this bed irregular chimney-
like excavations filled with a soft
cream-coloured stone containing
crowded, very fine iron grains; also
Montlivaltia, <Acanthothyris spinosa,
Limatula gibbosa, Ctenostreon pectint-

1 Maes, in Welsh, means ‘a plain, an open field,’ and sucha description
exactly applies to this elevated, almost isolated, flat tableland.

ee ee

|
.
|
:
|
q

~~ ——_—-—_” -.

———

Mol. 52.] ON THE UPPER PORTION OF DUNDRY HILL, 685

Section VII. (continued).
ft. ins. ft. ins.

GaRanTIANzZ forme, Pholadomya sp., Trigonia sp.,
(cont.). were found in these excavations or in
the film of this matrix on the top of
the bed. Actgonina, sp., was found in
a tube perforated in the crystalline

LEE eS ae ae ey ee ee 0 5
3. ‘The Conglomerate-bed.’ Pale grey,
erystalline limestone containing many
derived lumps of a bluish-grey sand-
stone, generally bored by Lithodomi,
and many more irregularly-shaped
lumps of an oolitic, limoniticironstone.
One flattened boulder of this sandstone,
measuring about 2’ 10''x14"x3",
considerably bored by Lithodomi which
remain in it, lay in the upper part of
the bed; Astarte Manselt, Myoconcha
crassa, Trigonia aff. costata, Limatula
gibbosa, Gouldia ovalis, Cucullea sp.,
Opis lunulatus, Ostrea sp., Pecten sp.,
Lima sp., Pseudomelania coarctata,
Cerithium subscalariforme, Ataphrus
obtortus, A. Labadyei, A. sp., Trochus
biarmatus, Natica sp., Belemnites
sp., Parkinsonia cf. Garantiana,'
and Strophodus sp., are indigenous.
There are derived fragments of
Grammoceras aff. aalense; much-
rolled fragments of Hildoceratide,
presumably Grammoceras spp., and
fragments of Dumortieria, mostly
showing a matrix of bluish-grey sand-

SLL ANS Sees Se nla. ite e o 6

bo
oo

Dumortieri£. 4. Compact, bluish-grey, argillaceous sand-
stone in two beds. It contains frag-
ments of two or three species of coarsely
and finely costate Dumortieri@é ......... 1 0

_ Immediately above the Dumortieria-beds lies the remarkable
conglomerate-bed formed during the Garantiane hemera—specimens
of Parkinsonia cf. Garantiana haying been found in it. Here, then,
is a case of very noticeable non-sequential deposition, denudation
being presumably the agency which has removed whatever strata
may have been deposited; and in all probability, considering the
short distance,—for the Ironshot Oolite is found in an arable field
only 7 furlongs to the west—there was originally at Maes Knoll a
sequence of deposits similar to that found at the Main-road quarries
and at Rackledown (see Sections IV., IX., & X.).

This denudation, no doubt, was in progress partly during
Bajocian time, and therefore it was contemporaneous with what
was called ‘ Bajocian denudation’ by one of us.? But it is evident

1 Slightly more umbilicate, a little more compressed.
? §. 8. Buckman, ‘The Bajocian of the Mid Cotteswolds,’ Quart. Journ. Geol.
Soc. vol. li. (1895) p. 431.
34 2

686 MESSRS. 8. S. BUCKMAN AND E. WILSON _—[ Nov. 1896,

that the progress of erosion was continued into Bathonian time, and
that the conglomerate-bed of Maes Knoll was largely formed out of
materials derived from what was really a post-Bajocian or Bathonian
denudation.

The next section shows the Marlstone and associated beds; and
by measuring with the level to the conglomerate-bed of the
preceding section the thickness of the Dumortieria-clay is approxi-
mately ascertained. This deposit is found to be of nearly similar
thickness at Maes Knoll to what it is at the western end of the hill.

Section VIT a.—Maes Knoll. 70 yards east of the Spinney
below the Tump.
ft. ims. ft. ms.
GarRanTiIANH. 1, Conglomerate-bed.

Dumortieria, 2. Clay and sandstones..............000 about (2:ueee. 60 0O
DisPansi. 3. Grey, argillaceous stone with widely
Scattered trom emails) csc... etweeeeeeces Ove AG
4. Greyish-drab, argillaceous stone with
scattered iron grains. Belemnites ... 0 5
———— 0a

Srriaturi? 5, Purplish-brown to drab, speckled stone
with belemnites, shell sections, am-
mOonites with a drab matrix) <2cs.c.ceen lmeceeee eee 0 1
VaRIABILIS. 6. Upper bed of blue rock with brown iron
grains and ferruginous lumps ......... 0 5
Lower, blue rock, scattered iron grains,
ferruginous lumps, and lumps of a
dense Wotlk Shomelepesesserc. eee ee ener OP

Sprnati. 7. ‘Maristone Rock.’ Very dense rock, a

ferruginous oolite. Psewdopecten equi-

valvis. A grey sandy rock forms the

lower 4 inches of this bed, while the

upper 4 inches is richly ironshot, with

red and Yellow bts! occ. -nwcccsewcesvcas -eeceeeeee 1 5
Marearitati? 8. Grey, thinly laminated, but massive un-

fossiliferous sandstone, found appar-

ently ‘at its. base tinvsiccccuncordéedecenaaestce se eeeeee 1 6

The next section is on the eastern side of the hill, and it is
remarkable for one thing—that the Marlstone is absent; so that at
this, the extreme eastern point, was found a condition of things
similar to that which obtains at the western end.

Section VII s.—Maes Knoll, on the eastern flank, overlooking
New Barn Farm. Special excavation.

ft.. “ims, |i sine:
Dunortteri#. 1. Stiff, greenish clay with harder beds of
argillacecus sandstone, extending up
the hill.
2. Pale yellowish-green sandstone, fragments
of Dumortieria aff. prisca, D. aff.
radians, Hudlestonia aff. serridens...... 0 6
3. Bluish and yellowish arenaceous ciay ... 2 6
Se ray

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 687

ft, irises” $b} ins.

DIsPANsI. 4, Yellowish, argiilaceous sandstone;
Hummatoceras, sp. nov., involute with

helmet-shaped whorls..................-0+ 0 5

5. Bluish arenaceous clay ..................00s 1 0
6. ‘Lhe Upper Rhynchonella-bed.’ Some-

what yellowish-brown, iron-speckled
stone. Lhynchonella af. Moore ...... 0 5

7. Brown, irregularly iron-speckled, tough,

earthy stone. Grammoceras Struck-

manni in the upper half, and canali-

culate belemnites. Haugia aff. Eseri,

STRIATULI. Gramm. striatulum, and numerous

(2 inches of bed cylindrical belemnites at the base and

7: the other 4 about 2 inches up. Rhynchonella aff.
inches of the 6'’" Moorei inthe bed. Thickness 6inches. 0 4
belongs to Dis-
pansi.) ae ee

8. Dark brown, coarse, but irregularly

ironshot stone—the grains generally

crowded. Grammoceras striatulwm not

uncommon; Gr. cf. Semanni | speci-
AHH + WSlMINIGEB cis cts coc cavseeewan cc andar 0 6

bo
lho

VariaBitis. 9. Stone with similar matrix. Fragments
of several species of the costate tuber-
culate Haugia aff. jugosa. One
fragment of a large, strongly costate
species of the Lillia Lill type,
Zeilleria aff. anglica (between Lycetti
PIL GUILT 5 2 Je vsnborine sagolcuanslen't ees 0. 3
10. Stone with similar matrix. Haugiu att.
jugosa, fairly large and fairly frequent,
but in very poor condition. Large
PCIOITIMILOR) 3.40282. als Soerecaes ng Bade OG. 2g
11. ‘The Lower Rhynchonella-bed.’ Stone
with similar matrix, Haugia sp.,
Rh. aff. Moorei! not uncommon. This
bed also contains the following derived
fossils, showing a pink matrix, and
more or less coated with iron oxide :—
Hildoceras bifrons, and _ especially
the thin form;* Dactylioceras, spp.*
Fragments of Harpoceras aff. falci-
Serum; also irony lumps ............... 0 4
12. Compact, blue, irregularly ironshot
limestone with iron lumps, bearing
worm-tracks, Derived lumps of a pink
matrix, and derived fossils—the sume
as in the overlying bed. Belemnites,
smooth Pectens, Rhynchonella ......... 0 4

Birrontis. 13, Compact argillaceous limestone, blue
and ironshot for the upper 5 inches,

1 It is a form different from the Rhynchonella in Bed 6.

2 See pl. xxii. figs. 30 & 31, in ‘Monogr. Inf. Ool. Ammonites,’ by 8. 8.
Buckman.

3 Three species :—1. Of. Desplacei, d’Orbigny, pl. evii. ; Dayi, Reynés, ‘Géol.
& Paléont. aveyronnaises,’ pl. v. fig.7. 2. Cf. subarmatum, Dumortier, vol. iv.
pl. xxviii. fig.6. 3, Of. commune, Sowerby, pl. cvii., but less coarsely costate.

688 MESSRS, S. 8. BUCKMAN AND E. witson _[ Nov. 1896,

Section VII B (continued).
ft. ims. ft. ins.
Birrontis (conz.). and pink, not ironshot, for the lower
3 inches. The blue part contains:
Fiildoceras bifrons, Dactylioceras) and
Harpoceras falciferum coated with iron
oxide, together with derived iron lumps;
also Rhynchonella. The pink portion
has a matrix similar to that of the
derived fossils in the overlying beds,
and it contains Harpoceras falciferum

FALcireri & H. exaratum. Thickness 8 inches . ———— 0 5)
lower 3 inches. 0 3
14. Pink clay. Harpoceras aff. Strangwayst,
UPSEUGONOCETOS 18) wie tots ere nee Ob
je Pale drab cartiy stone. c.c.cse. mete 0 5

16. Pinkish-drab, ironshot, earthy stone
with lumps of greenish stone bored
by Lithodomi, and covered with iron
oxide, Dactylioceras and belemnites ... 0 9

17. Greenish clay, about 34 feet proved,
without a sign of Marlstone or of any
hard rock.

The fossiliferous strata associated with the ‘ bifrons-beds’ are
interesting for the regular sequence of different ammonites. There
are, at the eastern end of the hill, thin fossiliferous deposits laid
down during the dispansi, striatuli, variabilis,” and bifrontis hemere,
comparable in amount to those found at the western end. During
the earlier portion of the variabilis hemera Jocal denudation was
evidently in progress, as is shown by the condition of the deposits
numbered 15 and 16; the bzfrons-beds have evidently been broken
up and redeposited just before or during the time of variabils.

Immediately above the thin stone beds occurs a considerable
argillaceous deposit, with a species of Hammatoceras at the base,
and species of Dumortieria in its main mass. This is what we
have called the ‘ Dumortieria-beds,’ and it is the same deposit as
that which we found at the western end of the hill. It is a notice-
able series, and we shall have something further to mention con-
cerning it (see p. 707).

1 Two species:—l. Cf. commune, Sowerby, pl. cyii., but less coarsely
costate. 2. Cf. annulatum, Sowerby, pl. cexxii. fig. 5 (the coarser-ribbed of his
two forms, but thinner).

2 It may be noted that although the deposits are said to have been laid down
during three hemerx, Dumortierie, dispansi, and striatuli, the exact ammonite
sequence found by S. 8. Buckman to obtain over a large extent of country is as
follows :—

. Dumortierie.

. Hammatoceras insigne, with other species of the genus.
. Grammoceras dispansum.

. Grammoceras Struckmanni, and allied species.

. Haugia Esert (with occasional species of No. 1).

. Grammoceras toarcense and Gr. striatulum, common.

rt bo CO HOU)

As an actual matter of fact, no specimens of Grammoceras dispansum have
been found at Dundry Hill. ;

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 689

It is now necessary to return, in order to study some sections
along another line of country.

Southward from Dundry Church are two exposures: one is Barns
Batch Quarry, at the bend in the road to Littleton on the southern
flank of the hill; and it yields the following section :—

Section VITI.—Barns Batch.
ft. ins.
Pale grey, crystalline, coarse-textured limestone and
ragstone massively bedded, but somewhat rubbly in
ESTATE E ncennlpee Se cae alt LiaRy thickness about 19 0

Note.—Here were obtained corals, Terebratula aff. globata, & Ostrea, the
same species as one that was found in the Coralline of the main-road quarries.

The other section is about two fields eastward in a small clump
of trees. On the 6-inch Ordnance map it is marked as a ‘ Gravel
Pit.’ We have called it ‘ Barns Batch Spinney.’

Suction VIII a.—Barns Batch Spinney.

Upper Beds. ft tines (eit) ina.

To top of hill, showing at intervals beds

like those at Barns Batch...... SpOUG “As .00- 45 0
1. Irregularly, thinly laminated, white

crystalline limestone with numerous

corals, large Thamnastrea, small

Ostrea, Pecten sp., Lithodomi, Cidaris

Fowleri, Terebratula sp., Rhyncho-

A | Se Rs a ea ne oe Le 5 0

Lower Beds.

SonnrniZ. 2. Irregularly-bedded limestone, of a
pale pinkish grey, with minute iron
grains and sparry sheils. A line of
large smooth ammonites (Sonninia
Jisstlobata ?) 5 to 6 inches from top,
Lima Etheridgii, Myacites jurassi,
Ctenostreon pectiniforme, Trigonia
striata (cast), Pecten sp., Spheroceras
EE OCE iE MAPLOTURGLES: | 0h Jekweiiieunstnn, | «ddbasv es 1 2
hardly separable from

Discita, 3. Laminated sandy limestone-parting,
forming an irregular and local divi-
sional line at this level. Lima
Etheridgii, Myacites jurassi....-... 6toT7

4. Compact, nodular, greyish limestone,
with irregular earthy partings be-
tween the nodular lumps; a large
smooth and a _ coarsely spinous
Sonninia, Hyperlioceras sp., Pecten
sp., Gresslya abducta, Myacites ju-
Ranta is ie ans deupheined ss aixnny ss 8to9
5. Pale grey, compact, nodular limestone

with earthy partings, infour blocks... 1 11 P

690 MESSRS, 8. 8. BUCKMAN AND E. WILSON _—[ Nov. 1896,

Section VIII a. (continued).
ft. ins. ft. ins.
CoNncavl. 6. Pale yellowish, compact limestone, with
scattered iron grains, more regularly
bedded than No. 5, with occasional
earthy partings: Lvocerus concavum,
Modiola Sowerbyana, Terebratula

TOLL CLAS AMEE Re SSA SEG ab coa tone Seatac CRmEPE ICSC ays)
BraDrorpDEnsis 7. Grey to brown, sandy and crystalline
AND limestone with small, scattered iron
Murcuison&. grains; very few fossils. A large
smooth ammonite and Terebratula

Eudesi (? shirbuirniensis) near thetop. ......... 4 38

Note.—The underlying beds are concealed by the quarry talus. The dip of
the beds here is nearly due east at about 3°.

The deposits marked Nos. 2-4 can be correlated in a general
way, without any difficulty, with the deposits shown in other sections.
No. 2 is the Lower White Ironshot bed on the horizon of jissilobata-
ovalis, the time of its deposition being that of the * Sonninie’
hemera. Our opinion of the time of the dep: sition of the other beds,
and consequently of their correlation, is shown in the margin.

It is important to notice that there is no Ironshot here, nor is
the Watchellia-bed present—these beds have, presumably, been
removed by denudation. Therefore bed No. 1 caps No. 2 non-
sequentially. We consider that bed No.1 is approximately contem-
poraneous with the Freestone in the large quarry by the church ;
but we are much puzzled as to the position of the 19 feet of stone
at Barns Batch, or of presumably a much greater thickness of deposit
above Bed 1 of this section, To the top of the hill on a fairly
steep slope above the Spinney there are some 45 feet of rock. Part
of the apparent thickness of the rock on this slope might be due to
repetition of the beds by step-faults; but we know that at least
20 feet of rock must be present on the evidence of Barns Batch. If
the thickness be no more than this, it is possible that all the beds
above No. 2 were deposited contemporaneously with the Freestone ;
but if the thickness be greater, two interpretations present them-
selves:—(1) There was a considerable thickness of limestone de-
posited subsequent to the Coralline beds*; or (2) all this limestone
was deposited before the Coralline beds, and therefore a much
greater thickness of a coarser-textured stone was laid down at
the south-western portion of the hill, while 20 feet of Freestone
were being deposited near the church, and 4 feet of limestone in
the northern roadside quarry.

The solution of the question may become a matter of economic
importance (see p. 710), and it is certainly of scientific interest—
especially if the first supposition prove correct.

Another direction from Dundry Church may be taken, namely,
S.E., to a section on the main road, at the edge of the southern
escarpment. The following details have been obtained :—

1 Tn that case it is quite possible that the Barns Batch beds may be a cal-
careous deposit contemporaneous with the argillaceous strata called ‘ Fullers’
Earth’ in other places, as is the case with the ‘Calcaire de Caen’ in Normandy.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 691

Secrion IX.—The Southern Main-road Quarry—east of the Chew
Stoke road on the edge of the southern escarpment.

ft. ins.
CoRALLINE 1. Coralline limestone mixed with clay, more stony
BeEps. above, more marly below. Zetlleria Waltoni,
Aulacothyris carinata, Rhynchonella subtetra-

C27 By ORES, THIIE. BD. cnn cin estes ows on en ntumosane os BO
EaquivatEent 2. Grey, slightly ironshot stone in regular beds and

oF FREESTONE. SER GUET gill colonia al eae i 3. 4
GARANTIANZ. 38. Grey, crystalline, somewhat ironshot ‘ragstone.’
Astarte Manseli, Rhynchonella subtetraedra,

Aulacothyris carinata. Corals .............6.0.000 0 10

SavzeEl. 4. Hard ironshot limestone with planed-off top.
The fossil bed, with numerous Sonninie and
Stephanocerata, and other fossils generally
agreeing with those met with in the same bed
in the Northern Main-road Quarry ............... eg
Wircnetiiz. 5. Whitish, ironshot limestone, where exposed much
broken up by the weather; when quarried 2 or
3 inches of this adheres to the overlying bed.
The upper part is best for Witchellie. Sonninia
ef. fissi/obata 6 inches from top.......:.sseeeeeeeee 0 8
6. Soft earthy stone with Sonninia of the ovalis-type
and other Sonninie, Ctenostreon pectiniforme,
EC ATES roses cade as caste ad aensvs0sd vette nscaee rae ke: O
Discirz.? 7. A similar limestone to base of quarry........... eteO). 6

Srcrton IX a.

The following details were taken of the beds in the south-eastern
corner of the quarry by E. Wilson in the year 1887. The pit
is now nearly filled up.

ft. ins
Be Re MRED IAW ODIO hs bpcsis «inn cin io wd dnarndncMabide cahm Sadvislin nsinwseeien'ce ae
2. Compact light-coloured limestone with small iron grains ......... a
3. Irregular clay parting.
4, Limestone, purplish-grey, compact, with small scattered iron
EMT. a2 ne. ae Ocies ates deca taenacte xe Seu era dete epeaDnaeeaeweknina ds 0 4
RRR REE AO alte gL gg gta ani pio dndneh bane sb eeeh aio nivendheis ailowaie's O. »3
6. Light-coloured, finely crystalline limestone with small, scattered
aR IESE TESS te sea iar BF aes ait is apladv'a~ se Swan AenersBwenen twee isaAria' es 0 4
7. Light-grey, finely crystalline limestone with ochreous nodules,

rather loose and rubbly. Terebratula, pectens, ammonites,

RRR POs SAAN ws ontrdna dsb ac neg dece! Wad aides'ssdeweanvint wav E32
8. More solid, pinkish limestone, compact and unfossiliferous or

nearly so, with more or less thickly scattered ochreous grains

IG, 0 AGL NUD STICTIOR 5 coon cudamoanshanssaaecesseecsiateaseccss Il. 6

9. Hard, subecrystalline, pinkish limestone with scattered ochreous
ra ree and ceed. da tacaliee tvawewretess ahuscoesa Ves

10. Hard, suberystalline, pinkish-grey limestone with scattered
SR carob eR) anatinas<Wlink dk yndichanshveniyunoncnesses One

11. Hard, subcrystalline, grey limestone with scattered ochreous
NE esi eind sv do da cudiddenviannmaremavriestsconcees 0 il
12. Pinkish-grey limestone to base of quarry ............seecscesseeeee oe 0 6
t @

Note to Section TX a.—This is the downward continuation of Section IX.,
presumably without any noticeable break, so that Bed 1 of Section IX a is

‘ The workmen had obtained specimens of Hyperlioceras in the quarry, and
they must have come from Bed 7 or below it.

692 _ MESSRS. S. 8. BUCKMAN AND E. witson _—[ Nov. 1896,

the same as, or just below Bed 7 of Section IX. The Terebratula in Bed 7 is
presumably 7’. cortonensis; and the ammonites are probably Hyperlioceras,
or allies of Lioceras concavum. The four or five lowermost beds were presumably
deposited during the Murchisone hemera, and have probably yielded some of the
fossils of that date now in the Bristol Museum. Compare with Sect. X., Bed 5.

The correlation of the deposits of Section IX. is easy—it is a
repetition of the northern roadside quarry. The noticeable points
are that the Ironshot and the Witchellia-bed are present, and that
there is only a thin deposit separating the Coralline from the Iron-
shot, so that there are no Freestone beds below the Coralline to be
expected in this part of the hill.

The last section which we have to mention is near Rackledown
Farm, situated on the south-western corner of the southern spur,
which is separated from the main mass of the hill by the valley
below East Dundry.

Section X.—Rackledown! Farm.

CoRALLINE 1. Pale greenish-yellow coralline rubble.

Beps. Aulacothyris carinata ......... about! | .822).0<< 4 0
FREESTONE 2. Thin-bedded, white limestone with

HqQuivaLeEnT. Maat) is dk. cenoseshe eee acne about “Sleteece 4 0
Sauzer and 3. ‘The Ironshot. Spheroceras Sauzei,

perhaps and a number of species of the Son-

WitcHELLIz. ninia propinguans-type. Probably also

including the bed at the base of the
Tronshot, from which so many species
of Witchellia come. This quarry has
yielded a good series, but they are

difficult to obtain im situ ...... AbDOUG: \cclecuece 3. 0
SonNINIE to 4. Beds helow the Ironshot. Several beds
Concavl. of pinkish-grey limestone with marly
partings. AMyperlioceras about 3 feet

6 inches from the base ......... about ......... nb,

Moecuisonz. 5. Somewhat irregularly bedded and
cross-jointed, very dense, pinkish-red,
crystalline limestone with small scat-
tered iron grains, getting more com-
pact upwards. The top of the bed is
somewhat planed off, and covered with
ferruginous nodularlumps. Zezlleria
anglica, hynchonella Stephensi?,

Mayacites alt. JUrasst* )....... ccde tone ASS
6. Tough crystalline limestone, yellowish
grey, with scattered iron grains ...... Pe

=I]

. Earthy limestone with scattered iron
grains, with interwedgings of irregu-
lar, compressed, ironshot, sandy clay.
Indwigia cf. obtusa on spoil-heap

with matrix similar to this bed ...... 0 5
Saeed 60
OpaLini ? 8. Pinkish-grey, somewhat ironshot, some-
what crystalline limestone. Phola-
COMO JUMIGUN DN vat Mcta ss isbe'vavascathiacten | beebamtene 2 8

1 On the 6-inch Ordnance map spelt ‘ Rattledown,’
2 From this bed, judging by matrix, a fine Ludwigia aff. obtusa, Quenstedt,
in the Bristol Museum, was obtained ; also the specimens of Cirrus.

Vol. 52.] ON THH UPPER PORTION OF DUNDRY HILL. 693

Bed 5 is hard and massive—very distinct from the rubbly
condition to which the other rocks of this section have been reduced.
It was certainly deposited during the Murchisone hemera, and part
of it, perhaps, during the bradfordensis hemera; but we have no
evidence on the latter head.

Of the remaining deposits it will be noticed that the Ironshot
extends to this quarry, and that the equivalent of the Freestone is
very thin; but of the beds generally we are unable to give any
precise details owing to the very tumbled condition in which the
strata are presented. There is enough evidence to show that the
series (Nos. 1-+) is an approximate repetition of what obtains in
the main-road quarries.

Such are the sections which we have examined, and upon these
and the rocks which they illustrate we have now to make further
remarks under the following headings.

TV. Tue DEVELOPMENT OF THE DunprRyY STRATA.

In order to show the development of the various beds as well as
their geographical extension, we have arranged the quarry and
other sections according to the three lines of country: W. to E.,
S.W. by 8. from Dundry Church, and N.W. to S.E.; and under
the names of the different sections, taken in this order, we have
placed the thickness of deposit which was formed during the several
hemerze—so far as we have been able to apportion it.

The results stated in figures in the first of the accompanying
Tables (I-IV) we have plotted to scale in a diagram (p. 695).
Concerning this diagram we would make the following remarks :—

We have taken the base of the bifrons- and associated beds as a
base-line.

We have found, as the result of numerous trials with the level
and many investigations, a thickness for the Dumortieria-beds of
50 feet at the western end, 55 feet at Kast Dundry, and 60 feet at
Maes Knoll.

We have found the iabletohs only in the eastern portion of the
hill, east of the main road, and no signs of it west of the main
road. It appears to be a bed which fluctuates considerably in
thickness; but perhaps the fluctuation shown in the diagram may
be partly attributed to the imperfect state of our exposures. We
know that it fails altogether at the eastern end of the hill, and also
at the western end; but it must be remembered that the place of
its westerly disappearance, as shown in our diagram, is only
conjectural,

We find at Maes Knoll that the Bathonian rests directly upon
Toarcian—Dumortieria-beds, and that no deposits of Aalenian or
Bajocian age are present.

Note.—The suggestion of false-bedding in the Freestone, and that only its top
bed continues above the Ironshot, must not be attributed to the authors. It is
an oversight in the representation by lines of the colour of the original diagram

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696 MESSRS. S. 8S. BUCKMAN AND E, WILSON

[Nov. 1896,

Tasie I1.—Donpry Cuvrcu to Barns Barcu Sprnney
(SourH-wEsT BY SourTH).

Western End,

Church and Barns Batch

Clements’ Spinney.
Yard.
HEMERZ :— ft. ins. ft." ams;
Pi Coxalllime) pec.) sce oheae sc 3)
TICE REESEOME) Ie ec! n.c0 Sanc'ce if F@) i 50 O
Garantian@ ............65. naa 6)
SGIBG, Se 86) nos eaR CSREES
Witchelli@ |... 0.0... 0.000005.
SOMME PEE stein ee en 2) pea
IDES GOR oe ses 55 sane OE i 10 3 eis
CONC AM re acento 36 Son
Bradfordensts .........006.0. ; eee Ay nae
Murchison@...........0 00065. Base hidden.
(GYDA TOG ae ao eee 1 6
LNGHYADSOS. Bonnoopo seo ee eases

1 The actual thickness deposited during each hemera at this locality is, on account
of the condition of the exposure, somewhat conjectural.

Taste J1I.—Dunpry Caurcu To RackLepown (SourH-rast).

Western End,
Church and
Clements’
Yard.

Dundry
Main Road,
Southern Quarry.

Rackledown
Farm.

HEMERZ :—
P(Corallline)\ieccks occ: -1- 22
? (Freestone)
Garantiane
ISCUCEUI Hite eso nemctoai ce sss
Witchellie@ ..........0. 00
Sonninie
Discite...... Be Oa etna Sc |
Concavi
Bradfordensis.............+.
Murchisone LS SRR
Opalini... voxcn cer bee enone
Aalensis
Dumortiert@ .........60 0:
Dispanst
Striatula
Bifrontis «0.00. .00000 00s e ee
BEV C UCT en eee F< ao

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SIS)

for)

We)

oO

sae rece

Or
QOoooc°cor & We rb

DWN ROW PB QOH

We find at East Dundry the full sequence of Aalenian deposits,
and of Bajocian until the Sauzet hemera—the Ironshot Oolite.
The top of this Ironshot is eroded, and from this eroded top to
the Marlstone is the same distance as from the eroded top of the
Dumortieria-beds to the Marlstone at Maes Knoll. Consequently the
Bajocian and Aalenian beds must successively disappear between
East Dundry and Maes Knoll, presumably on account of denuda-—
tion; but where, can be suggested only approximately on our.

Quart. Journ. Geol. Soc. Vol. LIT.

Taste LV.—

| T'o face p. 696.

THE SEQUENCE OF Deposits at DunpRY HILt.

Chronological Terms.!

Epochs. Ages. Hemerz.?
| [-
Post-GARANTIAN®.
(The exact date is
uncertain.
ee 7 D 0 7
- : se
= Fs
3 2 VARIABILIS.
3
a H

(ere SS Fee ee eee

Stratigraphical Terms employed

Deposits made during the stated times. until recently.

Possibly the Barns Batch strata. (See Sections VIII. &

VIIL4., and remarks thereon.)

The Coralline beds: a coralliferous stone mixed with
much marl, occupying the highest parts of the hill;
its upper portion removed by recent denudation. (Sec-
tion III. Beds 1 & 2.)

The Blue Ironshot—the Rhynchonella-beds or the bifrons-
beds. (Section VII z. Beds 4-13.)

-
a a i -_

Quart. Journ. Geol. Soc. Vol. LIT. (To face p. 696.

Taste 1V.—T ue Sequence or Deposits at Dunpry Hut.

i 5 F Stratigraphical T:
Chronological Terms. Deposits made during the stated times. = Saat ante ed
Epochs. Ages. Hemerse.? |
(| Possibly the Barns Batch strata. (See Sections VIII. &
VILL 4., and remarks thereon.)
The Coralline beds: a coralliferous stone mixed with
much marl, occupying Be highest parts of the hill;
Pos Giekemecees its upper portion removed by recent denudation. (Sec-
(@belerack date is tion III. Beds 1 & 2.)
rs ra a ——uncertain.)__ Phe Freestone a local deposit of stone of economic-valne, | Pa Fin soni 200, —_——
= passing laterally into thin beds of no value, except as
z inferior roadstone, which we have called ‘ Freestone
g | equivalent.’ (Section III. Beds 3 & 4; Section IV.
a Bed 4.)
z L
ia)
A thin deposit not always to be detected (Section II.
GARANTIANZ. Beds 1 & 2), =the Conglomerate-bed of Maes Knoll
i (Section VII.).
is)
I
ZB Nrorvtensts. No deposits of this date have been found on the hill.
a L
5 i
BS The same as above. If any deposit were made, it was
a HuMmprrtiestant. removed by the denudation which took place during
By this or the subsequent hemera.
The Ironshot : a deposit which the Bajocian denudation
Savzer. has removed from most of the hill. (Section IV.
s Bed 5.)
5
Sa f
3 WHECRS DER: Te a ans Tronshot—the Witchellia-beds. (Sec- Humphriesianus-zone,
u : The Lower White Ironshot—the fissilobata-ovalis horizon.
SONNINIZ. (Section I. Beds 4-8.)
U Discirz. The Grey Limestone and Marl-beds—the discites- and | 2 erhaps considered as Humphriesianus-
L — concavus-beds—the Terebratula Budesi-beds. (Sec- zone, perhaps as Midford Sands, by
if a tion I. Beds 9-18.) ane authors. Later concavus-
ONCAVI. eds.
BRADFORDENSIS. f ; The Murchisone-zone was not recog-
Ss a _| The hard irony beds exposed as massive rock at Rackle- nized as occurring at Dundry by
4 down Quarry. (Section X. Beds 5-7.) earlier geologists. Later Murchi-
er Murcuisonx. sone-z0ne.
3 aceon =
=
OpALrnt.
—————— —— | The bottom beds (of stone). (Section I. Beds 24, & 25.)
: AALENSIS.
iS | SSS ~ -
The Upper Clay beds—the Duwmortieria-beds. (Sec- |
| DomorqirRiz. tions VII 4. Bed 2, VII n. Beds 1-3.)
= DisPanst. | |
iS) : |
a Upper Lias generally.
Z eS S@PRIATULI. Ei oa aaa |
eS S ae The Blue Ironshot—the Riynchonella-beds or the bifrons-
S 3 | VARIABILIS. | beds. (Section VII 3B. Beds 4-13.)
=| a | Peas ie eS
— Uh | SS = ——
Brrrontis. |
|
|
Wavoueeers | Sao eres y asa Upper Lias. (Section VII xz.
c Naa |
¥ SPINA. | |
4 The Marlstone. (Section VII a. Beds 7 & 8.)
gy MARGARITATI. |
5 |
2 | i
a | The Lower Clay bed. (Section VII. Bed 17.)
Ro
oy

1 [We may explain that the terms ‘Bathonian,’ ‘Bajocian, etc. are used only as chronological terms to indicate
certain ‘Ages’; that such ‘Ages’ are made up of so many hemerw; that a hemera is a period of time marked by
particular zoological phenomena; and therefore that any group of hemere—an Age—must also be similarly governed
in its extent by zoological phenomena. Since, in the present cases, the hemers are governed by the zoological phenomena
connected with ammonite species, therefore the Ages must be governed by the phenomena of larger ammonite groups.
Hence we use the terms as follows :—

Hemere from niortensis onwards up to (?) what

Barnontan AGE. is called Oxtordian. (We do not pledge our- Zoological phenomena :— Predominance
selves as to its upper limits.) of Parkinsonia and allied genera.
Basocran AGE. Hemere : discite to Humphriesiani inclusive. Acme and paracme of Sonninine.
AsLENIAN AGE. Hemerx : aalensis to concavi inclusive. Tacdwigia and allied genera of Hildo-
ceratida.
Toarcian AGE. Hemere : falciferi to Dumortieria. { Grammoceras, Hildoceras, and allied
genera of Hildoceratide.

Practically the Toarcian and Aalenian Ages correspond to the acme and paracme of the Hildoceratide; and at one
time S. S. Buckman proposed to call these divisions by the one name Toarcian (‘The Cotteswold, Midford, and Yeovil
Sands,’ Quart. Journ. Geol. Soc. vol. xlv. 1889, p. 461); but subsequently it was found that the length of this Age would
be out of all proportion to the length of others. ‘Therefore, acting partly on a suggestion made hy Dr. E. Haug, he
has adopted the divisions Aalenian and Toarcian, taking note of the zoological phenomenon of the appearance of the Poly-
morphide—genera Dumortieria, ete—as a break in the predominance of the Hildoceratide. Hence the Toarcian Age is
brought to a close with the zoological phenomenon of the predominance of the Polymorphidw, and the Aalenian, which begins
with the renewed predominance of the Hildoceratidie, continues until the Sonninine become of greater importance than the

Hildoceratide—that is, just before the final complete extinction of the Hildsceratidie. ; 3
A nearly completed paper by S.S. Buckman more fully explains these views, and the reasons for their adoption —Angust 31st,
1896. ]

? Concerning this term and the designatory hemeral names, see S. S. Buckman, ‘ The Bajocian of the Sherborne District,’
Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 479, and ‘ The Bajocian of the Mid-Cotteswolds,’ ibid. vol. li. (1895) p. 388.

’ Henry Shaler Williams proposed to distinguish the divisions of an Era (our Epochs) by prefixing the syllables
Bo-, Meso-, Neo- when three divisions were required (‘Dual Nomenclature in Geological Classification, Journal of

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 697

diagram. However, we have found that the Ironshot rubble occurs
in a ploughed field 4 mile east of Walnut Farm.

West of East Dundry, as before stated, we have found that the
Tronshot Oolite does not extend to the freestone-quarry near the
church. How far east of that it disappears we can only suggest
in the diagram, since there are no data available after passing the
northern roadside quarry.

The line of Bajocian denudation consequently runs with a slight
easterly rise from the western end of the hill to East Dundry ;
then it continues practically level for a space, and finally it falls with
an easterly dip to Maes Knoll. It is indicated in the diagram by a
thick dark line.

The one other point in connexion with this diagram which
demands our attention is the rapid easterly attenuation of the
Freestone.

V. Tue SrRaTIGRAPHICAL SEQUENCE AT Dunpry HI tt.

No one exposure shows the full thickness of the deposits which
we have examined, but by the correlation of the various sections
a generalized section of the hill is obtained (Table IV).

From this Table it may be seen that there is a break in the due
sequence of deposits at Dundry Hill. As a matter of fact, this
break in the sequence is least in the middle of the hill; but to the
west it is greater, in such wise that strata of the Garantiane hemera
rest directly upon strata of the Sonniniw hemera; while to the east
it is very marked—the strata of the Garantiane hemera lying
directly upon those of the Dumortierie hemera.

VI. Tue Faunat Sequence at Dunpry Hitt.

As Table I. (p. 694) has shown the different deposits which have
been laid down at Dundry Hill, together with the dates to which
we assign such deposits, it is now possible for us to show in
Tables V. & Va. the sequence of faunas which lived during the deposi-
tion of the strata in question. In part this list, which claims to be
only an approximate record, by no means complete, has been compiled
from the results of collecting during the work of noting the different
sections ; but much of it is based upon our knowledge of speci-
mens collected during previous years by ourselves and by other
geologists.. We are enabled to state more or less approximately
the geological date of the species so collected by observation of the
character of the matrix; for it may be seen from our sections that
the deposits made during different times are easily recognizable by
their lithological characters. ‘Cases of doubt of course occur, and

such cases are marked by the placing of a note of interrogation
before the generic name.

? We are indebted not only to those geologists by whose labours the Bristol
Museum has been enriched in the past, but also to those who have done so
much work at Dundry Hill in the present, Mr. J. W. D. Marshall, Mr, J. W.
Tutcher, Mr. A. Vaughan, B.Se., and other members of the Bristol Geolo-

gists’ Association, to whom’ we owe our best thanks for kindly submitting
specimens for our examination.

698 MESSRS. S. S. BUCKMAN AND E. witson _[ Nov. 1896,

Taste V.—TuHe Faunat Sequence at Denpry. [S. 8. Buckman. ]

Those marked + are type-forms named from Dundry specimens. Those figured from
Dundry but not specific types are marked (*).

HEMERZ. CEPHALOPODA. BRACHIOPODA. |
Zeilleria Acanthothyris |
Waltoni. panacanthina.
Terebratula ‘tRhynchonella
globata. subtetraedra.

Terebratula decipiens ?
tTerebratula Acanthothyris

Post-GARANTIANE spheroidalis. spinosa.
(Coralline and Terebratula, an
Freestone). ovoid feebly bi-

plicate form of

the punctata- Rhynchonella

group. plicatella.
Terebratula aff. Phillipsi, but

shorter and less plicate.
Aulacothyris carinata.
Rhynchonella aff. parvula.

Parkinsonia garantiana, d’Orb. | +Rhynchonella subtetraedra.

Spheroceras att. Brongniarti, Acanthothyris spinosa.
Sow. Rhynchonella att. angulata, Sow.
Terebratula between globata and
GARANTIANZ. Hollande.

Zeilleria, sp. cf. Davidson, ‘ Bra-

chiopoda,’ Suppl. pl. xxiv. figs. 16

&17; also cf. Hughesi.
Belemnites.

+Stephanoceras contractum, J.| Terebratula aff. Hartmanni.

de C. Sowerby. Acanthothyris paucispina.

Stephanoceras Sauzei, d’Orb. A somewhat flattened Terebra-
RS Braikenridgii, tula aff. spheroidalis.

J. de C. Sowerby. +Rhynchonella dundriensis, S.
Stephanoceras aff. Bayleanun, Buckm.

Oppel.
Stephanoceras, a crassicostate

form.

SaUZEI. +Sonninia corrugata.
ri mesacanthus (Waa-
gen).

Oppelia preradiata, Douvillé.
‘ Cadomoceras, sp.

+Sonninia Sowerbyi (Miller).
Belemnites aalensis, Voltz.

ws ellipticus, Miller.
Nautilus ornatus, Foord and
Crick.

}+Witchellia leviuscula.
WITCHELLIZ. 53 aff. Sutneri.
Spheroceras Brocchi (Sowerby).

Vol. 52.]

HEMERZ. CEPHALOPODA.

(*) Lissoceras, sp.? ‘Am. subradi-
atus,’ S. P. Woodward, non
Sowerby.
(*)‘ Spheroceras, the small form
called Brocchii by Sowerby.
tSonninia Browni, Sowerby.
55 ssilobata.
SONNINIZ. Sy eel (S. Buckm.).
2 ovalis.
$5 aff. gracililobata
(Quenst.).
Sonninia Zurcheri.
Strigoceras compressum (Ethe-
ridge).

LTissoceras Etheridgii, 8. Buck-
man.
Hyperlioceras aff. discites.
i aff. Walkeri.
Lioceras intermedium.
Belemnites Blainvillei.

DIscitTz.

Lioceras concavun.
ConcaAvI. » -V-seriptum.

LTioceras cf. bradfordense.

Braprorpensis&| L”™igia obtusa (Quenstedt).

MvuRrcHISON2.

Grammoceras
Branco.

Grammoceras aft. lotharingi-
cum (Branco).

Opatini & Grammoceras aalense (Zieten).
AALENSIS. = aff. aalense

(Zieten).

Grammoceras leurum, 8S. Buck-
man, cf. ‘Monogr. Inf. Ool.
Ammonites,’ Pal. Soc. vol. for
1889, issued 1890, pl, xxxiii.
fig 8.

Grammoceras subcomptum.

subserridens,

Catulloceras Dumortieri (Thi-
olliére).

Dumortieria aff.
(Reinecke).

Dumortieria aff. prisca, S.
Buckman.

Hudlestonia aff. serridens.

Hammatoceras, sp., in the early
part of this hemera,

Q.J.G.S. No, 208.

radians
DUMORTIERIZ.

ON THE UPPER PORTION OF DUNDRY HILL.

P 9

699

Tasre V. (continued).

BRACHIOPODA.

? Terebratula aff. Uptoni, S.
Buckm. [coll. Mr. J. W. D.
Marshall. |

Terebratula crickleyensis, S.
Buckm. [coll. Mr. J. W. Tut-
cher. |

Terebratula
Buckm.
Terebratula Eudesiana,S. Buckm.
Rhynchonella Forbesi, Dav.
(‘immediately above stone,
with Terebratula EudesiZ

E. Wilson).

cortonensis, S.

+Terebratula Eudesi, Oppel.
‘

ee perovalis, Dav.
is cortonensis.

Terebratula shirbuirniensis.
Leesi.
a Etheridgii, Dav.

4
tZeilleria anglica, Oppel.

Rhynchonella aff. Stephensi, Dav.

Rhynchonella, sp., like a dwarf
form of cynoprosopa, S. Buckm.

Rhynchonella Stephensi.

Terebratula att. infra-oolithica,
E. Desl.

Aulacothyris Blakei.

? Zeilleria aff. Lycetti.
Rhynchonella Moorei, Dav.

700

HEMERZ.

DISPANSI.

STRIATULI.

VARIABILIS.

BIFRONTIS.

FALCIFERI.

SPINATI &
MARGARITATI.

MESSRS. S, S. BUCKMAN AND E. WILSON

[Nov. 1896,

Taste V. (continued).

CEPHALOPODA.

Grammoceras Struckmanni.
a doerntense,
Denckm.

Grammoceras striatulum.

29 toarcense.

MY aff. Semanni.
Haugia aff. Eseri.
Canaliculate belemnites.
Cylindrical belemnites.

Haugia aff. yugosa.

Haugia, nu. sp., aff. illustris,
Denckm.

Form of the Lillia Lilli type.

Dactylioceras aff. Desplacei.

es cf. commune.
aA aff. subarmatum,
Dumortier.

Hildoceras bifrons.

Dactylioceras aff. commune.
:. aff. annulatum.
Harpoceras falciferum (Sow.).

36 exaratum.
aff. Strangwaysi
7 (Sow.).
- capellinum(Quenst.).

Pseudolioceras ?, sp.
Hildoceras Levisoni.

Pleuroceras

(Quenst.).

Amaltheus margaritatus.

aff. nudum

BRACHIOPODA.

Rhynchonella aff. jurensis, Dav.,

non Quenst.

Rhynchonella aff. juwrensis, Dav.,

non Quenst.!

Zeilleria between Lycetti and
anglica.

Rhynchonella aff. jurensis, Dav.,
non Quenst., but a form different
from those mentioned above.

Terebratula punctata.
Rhynchonella tetraedra.

*, northamptonensis.
Zeilleria indentata ?, fragment.
Rhynchonella aft. subdecussata,

Zittel, ‘Geol. Beobachtungen
aus den Central Apenninen,’
pl. xiv. (2) fig. 12; Geogn.
Pal. Beitr. vol. i. pt. ik
Munich, 1869.

1 Said by Mr. J. F. Walker to be near his Rhynchonella bothenhamptonensis, mentioned but
not figured, Geol. Mag. 1892, p. 442.

Vor §2.} ON THE UPPER PORTION OF DUNDRY HILL. 701

Paleontological Notes upon certain Species mentioned in
the foregoing Table. [S. 8. Buckman. |

Stephanoceras contractum.—The type came from Dundry; whether
the name Sawzei may also be used for a coarser form than Sowerby’s
is a matter for future determination. It seems probable; but the
two forms are closely allied. They are not true Stephanocerata.

Spheroceras Brocchi.—The larger of the specimens figured by
Sowerby must be taken as the type, and it is from Sherborne
(Dorset). The smaller is a different species, much more umbilicate,
and is from Dundry. It is a common form, but it has no name.

Strigoceras compressum (Etheridge).—In the communication in-
corporated in Wright’s paper, Etheridge quotes a species as ‘ Ammo-
nites Truellii, var. compressus.’! This may be translated as an
ammonite with characters like 77rwellii, but more compressed. The
description applies to more than one species of Dundry ammonite,
but probably the largest of the forms of Zruellic-like ammonites
may merit the name best.

a subradiata (J. de C. Sowerby).—The author says’:
‘Found... on the road from Bath to Bristol; it has been mee
out of a mass of Ironshot Oolite.’ The species now usually called
by this name lived during the niortensis hemera, but, as there are
no strata of that date at Dundry Hill, there must be some mistake
in the present identifications. ‘The type presumably came from the
Ironshot bed of the Sauzec hemera, or from the softer stratum just
below; but I am unable to say anything concerning it. As
subradiatus is the type of the genus Oppelza, its correct identifi-
cation is a matter of great importance, and the result may alter
entirely the present application of the generic term Oppelia. As
Sowerby’s type is in the British Museum, a further comparison of
the Dundry Oppelie therewith will be the solution of the difficulty.

Tnssoceras 2? ‘subradiatum’ (S. P. Woodward), non J. de C.
Sowerby.—This is not the same species as the Ammonites sub-
radiatus of Sowerby, and in fact 8. P. Woodward himself notes
points of difference.* It may not be the same genus, for it possibly
is a parent of oolithicus, d’Orbigny, the type of Lissoceras, which
Sowerby’s subradiatus certainly cannot be.

H. B. Woodward states that the specimen came from the Parkin-
soni-zone,* but this must be an oversight. The probable horizon
is given in Table V. It certainly did not occur above the Iron-
shot, but the exact identification of the fossil, for there are several
allied forms, is not possible from the figure given by 8S. P. Wood-
ward. This also is a matter for comparison with the actual specimen
in the British Museum.

1 Quart. Journ. Geol. Soc. vol. xvi. (1860) p. 24.

> «Min. Conch,’ vol. v. p. 23,

3 «The Geologist,’ vol. ii. no. 33, p. 328.

* Mem. Geol. Surv., ‘The Lower Oolitic Rocks of England,’ in ‘ Jurassic Rocks
of Britain,’ vol. iv. (1894) p. 99. ee

BZ

702 MESSRS. 8. 8, BUCKMAN AND E. wiLson _[ Nov. 1896,

Pleuroceras aff. nudwm (Quenstedt).—The species is between
Pleuroceras vittatum, Phillips, ‘Geol. Yorkshire,’ pl. xiii. fig. 1, and
Pleur. nudum, Quenstedt, ‘ Der Jura,’ pl. xxi. fig. 8. Itis, however,
without the tubercules shown in the first species, particularly the
inner row, while it is much more distantly costate than the other,
and presumably a more robust shell than Quenstedt had to figure.

Rhynchonella dundriensis, 8. Buckman.—The type is in the
Bristol Museum, and no other specimen has been found at Dundry.
The appearance of the Dorset specimens suggested that the species
lived in the Humphriesiani hemera, the given locality, Bradford
Abbas, being often applied somewhat indefinitely by the working
fossil-collectors. However, there are no strata of the Humphriesiani
hemera at Dundry; and so the date now assigned is more likely to
be correct, both for Dundry and Dorset.

Terebratula aff. infra-oolithica, EK. Deslongchamps.—The speci-
mens mentioned by this name agree closely with examples of
T. infra-oolithica from Condé-sur-Sarthe, kindly given to me by
Prof. Bigot. They differ in the smaller size of beak and foramen,
and a slightly more pronounced carination of the perforate valve.
Both the Dundry and French forms differ appreciably from the
Dorset specimens which have hitherto been identified as 7. infra-
oolithica.

Zeilleria anglica (Oppel).—In his ‘ Juraformation,’ p. 425, § 53,
No. 216, Oppel gave this name to a shell which he collected at
Burton Bradstock with Amm. opalinus, torulosus, and submnsignis.
He says the specimens agree remarkably (‘ stimmen auffallend ’) with
the species figured by Davidson, Mon. Brach. (Pal. Soc.) vol. i. Append.
tab. A, figs. 10-13. from the Inferior Oolite of Dundry. There are,
however, certain differences to be noted in these shells. The Burton-
Bradstock specimens, which are from a lower horizon, are certainly
more lenticular, have more convex valves, a more prominent umbo,
and a more distinctly separated beak, with a larger foramen. This
Burton Bradstock shell agrees better with what Deslongchamps has
figured as Terebratula (Waldheimia) Lycetti, Pal. Frang., Brachio-
podes, pl. xlvii. figs. 4-10; but this is not the Lycetic of Davidson,
which isa more elongate shell. As Oppel did not figure his shell,
but gave.a reference to Davidson, and as Davidson’s shell has been
figured by the name anglica, and known by that appellation so long,
it is desirable to leave it untouched; but the Burton Bradstock
shell may be distinguished as Zeilleria Oppel.

Zeilleria Oppeli, 8. Buckman.

1856. Terebratula anglica, Oppel, pars, ‘ Juraformation,’ p. 425.

1862. Terebratula (Waldheimia) Lycetti, Deslong. (non Dav.) ‘ Brachiopodes Terr.
Jurass.’ pl. xlvii. figs. 7 & 9.

Description.—A subpentagonal shell with somewhat gibbous
valves uniting in an almost sharp margin. ' Beak fairly incurved,
distinct, foramen rather large, beak-ridges and area fairly pro-
nounced.

Quart. Journ. Geol. Soc, Vol. LIT. [To face p. 702

Paste Va.—Tun Faunat Sequence at Dunpry. [E. Wizson. ]

Ni t Saw, b c ice u i
ote-—Those marked + are type-forms named from Dundry specimens. Those figured from Dundry, but not specific types, are marked (*)

a ee ee I ANS SN

EMERZ G )

. ASTE

H ROPODA. LAMELLIBRANCHIATA, EcCHINODERMATA CoRALS ETC
? ’ .

Se ee

Pleurotomaria Palemon (d’Orb.). Trigonia costata (Sow.). P Pentacrinus Milleri, Avst
Lithodomus inclusus, Phil. Magnotia Forbesi, Wright.
Asse gregaria, Sow. Hemicidaris granul osa, Wright.
AMA, Sp. Cidaris Fowleri, Wright. is

» Bouchardi, Wright.
? Holectypus hemisphericus, Ag.
Collyrites ringens, Ag.

Opis similis, Sow.

? Myoconcha crassa, Sow.

? Cypricardia bathonica, VOrbd.
Pecten barbatus, Sow.

Unicardium gibbosum, M. & I.

Pleurotomaria actinomphala, Desl.
- monticulus, Desl.
= armata, Minster.
. oxytera, Hudleston.
+ Amberleya ornata, Sow.
+ Alaria dundriensis, Tawney.
+ Natica dundriensis, Tawney.

WITCHELLIZ.

Quart. Journ. Geol. Soc, Vol. LIT,

Taste Va.—Tun Fauna, Sequence at DuNDRY.

[To face p. 702.

[E. Wirson. }

Note—Those marked + are type-forms named from Dundry specimens. Those figured from Dundry, but not specific types, are marked (*).

HEMER.

GASTEROPODA.

LAMELLIBRANCHIATA.

Ecurnopermara, Corats, Ere.

Post-GARANTIAN® (Coralline
and Freestone).

Pleurotomaria Palemon (dOrb.).

Trigonia costata (Sow.).
Lithodomus inclusus, Phil.
Ostrea gregaria, Sow.
Lima, sp.

? Pentacrinus Milleri, Austen.
Magnotia Forbesi, Wright.
Hemicidaris granulosa, Wright.
Cidaris Fowleri, Wright.

s, Bouchardi, Wright.

? Holectypus hemisphericus, Ag.
Collyrites ringens, Ag.
ttiyvoctypus ovdtis, Wright.
Stomechinus intermedius, Ag.

5) bigranularis, Lam.
Isastrea Richardsoni, B. & H.
5) Lonsdalei, . & H.
_ tenuistriata, M‘Coy.
= explanata, M‘Coy.
Phamnastrea Defranciana, Mich.
te Terquemi, EB. & H.,
M.-Edw.
Latimeandra Flemingii, B. & A.
Montlivaltia lens, KH. & H.
Glyphea rostrata ?
Strophodus, sp. ?

GARANTIANE.

Pleurotomaria Palemon, VOrb.
Pseudomelania aft. coarctata, Des}.
Ataphrus Labadyei, V Arch.

Py obtortus, Hudleston.
Trochus biarmatus, Miinst.
Natica bajocensis, d Orb.
Trochus dimidiatus, Sow.
Amberleya aft. ornata, Sow.

Lima Lycetti, Laube.
» semicirceularis, Goldfuss.
Astarte aft. obliqua, Desh.
3» Manseli, S. Buckm.
Limatula gibbosa, Sow.
Gouldia ovalis, Quenstedt.
Ctenostreon pectiniforme, Sow.
Trigonia costata, Sow.
Opis angulatus, J. Buckman.
+ ,, linulatus, Sow. [Lycett.
Trigonia ct. Moretoni and Walford,
duplicata, Lycett.

Montlivaltia lens, B. & H.

Pleurotomaria elongata, Sow.

Goniomya angulifera, Sow.

Serpula grandis, Munster,

x phyospira, V Orb. Astarte multicostata, S. Buckm. Diplocidaris, sp. (spine).
= armata, var. Mun- Myacites Jurassi, Brong.
steriana, Desl. Gervillia Hartmanni, Minster.
a ornata, Sow. Pholadomya spatiosa, Whidhorne.
a granulata, Sow. 5 decemcostata, Romer.
+ a distinguenda, Tawney “A cf. fidicula, Sow.
5 Sasciata, Sow. + Harpax Pawneyi, Whidborne.
+ a sulcata, Sow. Opis lanulatus, Sow.
SAUZETI. (*) en subreticulata, dV Orb. Cucullea oblonga, Sow.
a Proteus, Desl. S elongata, Sow.
5 abbreviata, Sow. 5 cancellata, Phill. ?
+ BS subaraneosa,Hudlest.| Ostrea flabelloides,Lam.=O.Marshii,
(*) ES paucistriata, d’Orb. Sow.
(*)Drochus Zetes, d’Orb. > explanata, Minster.
Ataphrus levigatus, Sow. Lima alticosta, Ch. & Dew.
Pseudomelania lineata, Sow. Hinnites abjectus, Phillips.
Cerithium subscalariforme, V Orb. Ctenostreon pectiniforme, Sow.
+ Spinigera trinitatis, Tawney. Tsocardia gibbosa, Mist.
+ Straparollus dundriensis, Tawney.
Pleurotomaria actinomphala, Des). Opis similis, Sow.
om monticulus, Desl. ? Myoconcha erassa, Sow.
A armata, Munster. ? Cypricardia bathonica, WOxb.
WITCHELLIZ. on oxytera, Hudleston. Pecten barbatus, Sow.
+ Amberleya ornata, Sow. Unicardium gibbosum, M. & I.
+ Alaria dundriensis, Tawney.
+ Natica dundriensis, Tawney.
Lima Etheridgii, Wright.
Myacites Jurassi, Brong.
Ctenostreon pectiniforme, Sow.
Sonnintz, Trigonia striata, Sow
Gresslya abducta, Phill. |
| | Pholadomya Murchisoni, Sow. |
|
| | Astarte elegans, Sow. |
a excavata, Sow. |
Discitz. Lima Etheridgii, Wright. |
| Myoconcha crassa, Sow,
Fe implana, Whidb.
Modiola Sowerbyana, V Orb. Serpula plicatilis, Minster, attached
Concint P Myoconcha crassa, Sow. to Lerebratula cortonensis and

BraDrorpeEnsis &
MuRcuHIsonz.

P 5 implana, Whidb.
? Ceromya bajociana, VOrb.

T. Eudesi.

Pleurotomaria\ Mopsa, Orb.

Ta 3 Stoddarti, Tawney.

+ a dundriensis,/Vawney.
" niortensis, V Orb.

(*) 3 cf. subdecorata,Miin.?
te Amyntas, VOrb.

ue punctata, Sow.
P+ Cirrus nodosus, Sow.
+ . pyramidalis, Tawney.
Pf 4, Leachii, Sow.
;, Calisto, VOrb.
Amberleya (Turbo) Stoddarti, Tawn.

Trigonia striata, Sow.
Myacites att. Jurassi, Brong.

? Opis trigonalis, Sow.

? Cypricardia cordiformis, Desh.

Opatini & AALENsrs.

Lima aff. Btheridgii, Wright.
Pholadomya fidicula, Sow.

DumortiERrtz to
FALcrrert.

No species have been recorded.

Spinatr & MarGarrpari.

Pseudopecten equivalvis, Sow.
Gryphaa cymbiwn, Lam. ; or
Ostrea gigantea.

Avicula.

1 There is some doubt as to the correct date of these Dundry Plewrotomaria, the character of the matrix of specimens in the Bristol Museum, in this as

in many other cases, being all the evidence available.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 703

Differences from the shell now called Zeilleria anglica.—The valves
are much more convex in every way, especially towards the pos-
terior portion of the shell. The fossil therefore appears thicker,
with a more pronounced anterior slope than Z. anglica. The beak
portion of the perforate valve appears more pronounced and curved ;
the beak too is itself larger, with more pronounced area and ridges,
and a decidedly larger foramen. ‘his matter of the beak is a very
noticeable character, because the beak of Z. anglica is small and
delicate to a marked degree.

Time of Existence. In the hemera scisst, or in that of opalinus ;
but Zelleria anglica lived during the hemera Murchisone.

Locality. Burton Bradstock, Dorset.

Remarks. Deslongchamps, op. cit. pl. xlvil. fig. 7, shows the shape
as well as the usual size: in fact, the specimens are but little larger
than this. On the other hand, Z. anglica attains to twice this size.
Deslongchamps’ fig. 7 also shows the character of the beak, and may
in this matter be suitably compared with Davidson’s pl. A, figs. 10-
13. Deslongchamps’ fig. 7 may be taken as representing Zeilleria
Oppeli with considerable fidelity.

The faunal sequence at Dundry shown by other classes of fossils
is given in Table V 4., facing p. 702.

The following is a list of the species described by Whidborne ! as
from the Inferior Oolite of Dundry, with the horizons, when they
are stated. It will be useful, as a supplement to the lists we have
given, to show what palontological results have been yielded by
Dundry. We would, of course, remark that his Humphriesianum-
zone is evidently of somewhat wide interpretation ; but it may be
considered to be principally ‘the Ironshot Oolite,’ with certainly
beds above and below—in all probability strata deposited from the
hemera discite until that of Garantiane.

Dunpry Mo.tivsca DESCRIBED BY WHIDBORNE,

Arca culmotecta, Whidborne.
* Astarte suffluta, Romer.
tCardium dundriense, Whidb.
t » pulsatum, Whidb.
t Cypricardia filoperta, Whidb.
t Gervillia gladiolus, Whidb.
* intermedia, Whidb.
tGryphea abrupta, Whidb.
» eymbium,? Lam. ‘ Humphriesianum-zone.’
, ” Sollasi, Whidb.
tHarpax Tawneyi, Whidb. ‘ Ironshot Oolite.’
Hinnites tenuistriatus, Minster. ‘Top of Humphriesianum-zone.’
Leda lacryma, Sowerby. ‘Base of Interior Oolite.’

* Figured specimens. t Type-specimens.

* ‘Notes on some Fossils, chiefly Mollusca, from the Inferior Oolite,’ Quart.
Journ. Geol. Soc. vol. xxxix. (1883) p. 487.

* He notes that this is truly a Middle Lias fossil. This is evidently a case of
confusion of the Marlstone with the Ironshot Oolite,

704 MESSRS. 8S. 8, BUCKMAN AND E. witson _[Nov. 1896,

Dounpry Mottvsca (continued).

Lima alticosta, Chap. & Dew. ‘ Upper part of Humphriesianum-zone.’
» @eguilatera, Buy.
» educta, Whidb.
5, plebeia, Chap. & Dew. ‘Ironshot Oolite.’
tT ,, poetica, Whidb.
» rigida, Sow.
semicircularis, Goldf. ‘Humphriesianum-zone.’
Lucina burtonensis, Lycett.
tMacrodon rapidus, Whidb. ‘Humphriesianum-zone,’
tMyacites subsidens, Whidb.
tMyoconcha unguis, Whidb.
implana, Whidb.
t Mytilus striatissimus, Whidb.
tNucula nuciformis, Whidb.
Ostrea explanata, Goldf. ‘ Humphriesianum-zone,
», palmetta, Sow., var. montiformis, Whidb.
Pecten aratus, Waagen. ‘ Humphriesianwm-zone.’
? ~,, cornutus, Quenst.
» jenestralis, Whidb.
» leviradiatus, Waag.
Tt ,, spinicostatus, Etheridge. ‘Beds above the Ironshot Oolite
belonging to the higher part of the Humphriestanum- zone.’
t Pholadomya callea, Whidb. ‘ Ironshot beds.’
+ JSortis, Whidb.
T , spatiosa, Whidb. ‘Ironshot beds of Humphriesianwm-zone.’
tPinna dundriensis, Whidb.
tPlacuna sagittalis, Whidb.
tPlicatula Soliasit, Whidb. ‘ Humphriesianum-zone, upper part.’
Placunopsis semistriata, Bean.
* Rhabdocidaris Thurmannit, var. repens, Whidb. ‘Upper beds of
Humphriesianum-zone.’
tSphera fimbriata, Whidb.
Spondylus nidulans, Ki. Desl. ‘ Humphriesianum-zone.’
t Zerebratula Tawneyi, Whidb. ‘ Upper beds of Humphriesianum-zone.’
t Thracia leguminosa, Whidb.

* Figured specimens. + Type-specimens.

VIL. Tue Correnation oF THE DunprRy STRATA WITH THE Rocks oF
THE CoTTESWOLD AND DorRsET-SoMERSET AREAS.

In four parallel columns in Table VI. the following informa-
tion 1s given :—

I. The time divisions—the sequence of hemere.
II. The sequence of deposits in the Cotteswolds which have been
laid down during these hemeree.
III. The sequence of Dundry deposits.
IV. The sequence of strata found in the Dorset-Somerset area,
south of the Mendips.

Thus in these four parallel columns the contemporaneous deposits
of each district may be noted side by side. Our remarks upon
the comparative development of the deposits in the different areas
will be found incorporated in the following pages.

Quart. Journ. Geol. Soc. Vol. LII.

[To face p. 704.

Taste VI.—Correnarion oF tHE Dunpry Srrata wire THE Rocks or THE CoTrEswoLD AND DoxrseEt-SomersEet AREAS.

HEMERZ.

-‘Zrezaet

TRUELLII! .

GARANTIANZ .....

NIORTENSIS........

NSAUZEIL ....-.2.

CoTTEsSWOLDS.

Limestones above the Clypeus-grit.
The Clypeus-grit.
The Upper Trigonia-grit.

No Strata.

No SrRatTa.

Perhaps the Phillipsiana-beds of

Dunpry.

(?) The strata at Barns Batch.
The Coralline Beds.
The Dundry Freestone.

The Conglomerate-bed of Maes
Knoll=the thin bed below the
Freestone at other places.

No Srrata.

No STRATA.

The Ironshot Oolite of Dundry.

DorsEtT-SoMERSET. |

The zigzag-beds of Broad Windsor, Dor-

set.

The fossil-bed of Halfway House with
Truellii and dorsetensis.

|
/
|
The Freestones of Sherborne. |

The upper part of the roadstone of |
Oborne = Bifurcaten Schichten of
Wiirttemberg.

The lower part of the roadstone of
Oborne = Coronaten Schichten of Wiirt-
temberg. /

|

The upper part of the Sandford Lane
mele

|

Quart. Journ. Geol. Soc, Vol. LIT.

Taste Va.—Tue Faunat Sequence at Dunpry.

HemeErx.

GASTEROPODA.

LAMELLIBRANCHIATA.

[To face p. 702.

[E. Wirson. ]

Wote.—Those marked + are type-forms named from Dundry specimens. Those figured from Dundry, but not specific types, are marked (*)

Ecutnopermara, Corats, ETc.

Pleurotomaria Palemon (d’Orb.).

Trigonia costata (Sow.).
Lithodomus inclusus, Phil.
Ostrea gregaria, Sow.
Lima, sp.

|

? Pentacrinus Milleri, Avsten.
Magnotia Forbesi, Wright.
Hemicidaris granulosa, Wright.
Cidaris Fowleri, Wright.

» Bouchardi, Wright.

? Holectypus hemisphericus, Ag.

Collyrites ringens, Ag.

Post-GarantTIAN# (Coralline
and Freestone).

Htyvocriypus ovdtis, Wrint. |
Stomechinus intermedi: us, Ag.
of bigranularis, Lam,
Isastrea Richardsoni, B. & H.

“A Lonsdalei, B. & H.

. tenuistriata, M‘Coy.

explanata, M‘Coy.
Thamnastrea Defranciana, Mich.

a Terquemi, EB. & H.,
M.-Edw.

Latimeandra Flemingii, B. & Fi.
Montlivaltia lens, B. & H.
Glyphea rostrata ?
Strophodus, sp. ?

Pleurotomaria Palemon, WVOrb.
Pseudomelania att. coarctata, Desl.
Ataphrus Labadyei, VArch.

or obtortus, Hudleston.
Trochus biarmatus, Minst.
Natica bajocensis, VOrb.

Lima Lycetti, Laube.
» semicircularis, Goldfuss.
Astarte att. obliqua, Desh.
- Manseli, 8. Buckm.
Limatula gibbosa, Sow.
Gouldia ovalis, Quenstedt.

Montlivaltia lens, BE. & H.

BraprorpEnsis &
Muvrcurson®.

»

2 Ceromya bajociana, VOrb.

GARANTIANZ. Trochus dimidiatus, Sow. Ctenostreon pectiniforme, Sow.
Amberleya att. ornata, Sow. Trigonia costata, Sow.
Opis angulatus, J. Buckman.
+ ., lumnulatus, Sow. [Lycett.
Trigonia ct. Moretoni and Walfordi,
¥ duplicata, Lycett.
Pleurotomaria elongata, Sow. Goniomya angulifera, Sow. Serpula grandis, Minster.
oh phyospira, VOrb. Astarte multicostata, 5. Buckm. Diplocidaris, sp. (spiue).
9 armata, var. Mun- Myacites Jurassi, Brong.
steriana, Desl. Gervillia Hartmanni, Minster.
a ornata, Sow. Pholadomya spatiosa, Whidborne.
5 granulata, Sow. es decemcostata, Romer.
7 a distinguenda, Tawney . cf. fidicula, Sow.
ie Sasciata, Sow. + Harpax Tawneyi, Whidborne.
aol eate a sulcata, Sow. Opis lunulatus, Sow.
SAUZzEI. (*) a subreticulata, a’ Orb. Cucullea oblonga, Sow.
53 Proteus, Desi. - elongata, Sow.
* abbreviata, Sow. Bs cancellata, Phill. ?
+ on subaraneosa,Hudlest.| Ostrea flabelloides, Lam.=O.Marshii,
(*) ri paucistriata, V Orb. Sow.
(*)Drochus Zetes, d’Orb. », explanata, Minster.
Ataphrus levigatus, Sow. Lima alticosta, Ch. & Dew.
Pseudomelania lineata, Sow. Hinnites abjectus, Phillips.
Cerithium subscalariforme, VOrb. Ctenostreon pectiniforme, Sow.
+ Spinigera trinitatis, Tawney. Tsocardia gibbosa, Mist.
+ Straparollus dundriensis, Tawney.
Pleurotomaria actinomphala, Desl. Opis similis, Sow. _
* monticulus, Des). ? Myoconeha crassa, Sow.
ee armata, Minster. ? Cypricardia bathonica, VOrb.
WITCHELIIZ. op oxytera, Hudleston. Pecten barbatus, Sow.
+ Amberleya ornata, Sow. Unicardium gibbosum, M. & L.
+ Alaria dundriensis, Tawney.
+ Natica dundriensis, ‘Tawney.
| _Lima Dtheridgii Wright. ~ — a
Myacites Jurassi, Brong.
Ctenostreon pectiniforme, Sow.
SonNINIZ. Trigonia striata, Sow
Gresslya abducta, Phill.
| Pholadomya Murchisoni, Sow.
Astarte elegans, Sow.
| i excavata, Sow.
Discrrx. Lima Btheridgii, Wright.
| Myoconcha crassa, Sow,
| nS implana, Whidb.
Modiola Sowerbyana, U Orb. Serpula plicatilis, Minster, attached
? Myoconcha crassa, Sow. to Lerebratula cortonensis and
Concavi. 2 implana, Whidb. T. Budesi.

Pleurotomaria! Mopsa, @ Orb.

t 35 Stoddarti, Tawney.

a7 .; dundriensis, Tawney.
5 niortensis, d'Orb.

(*) ‘e cf. subdecorata,Miin,?

a Amyntas, VOrb.
5 punctata, Sow.
?+ Cirrus nodosus, Sow. |
+t 5, pyramidalis, Tawney.
Pf 4, Leachii, Sow.
;; Calisto, VOrb.
Amberleya (Turbo) Stoddarti, Tawn.

”

Trigonia striata, Sow.
Myacites att. Jurassi, Brong.

? Opis trigonalis, Sow.

? Cypricardia cordiformis, Desh.

Opatint & AALENSIS.

Lima aft. Etheridgii, Wright.
Pholadomya fidicula, Sow.

Dumortierre to
FALcrrerti.

No species have been recorded.

Sprnatr & MarGarrrati.

Pseudopecten equivalvis, Sow.
Gryphea cymbiwm, Lam. ; or
Ostrea gigantea.

Avicula.

1 Ther

in many other ce

is some doubt as to the correct date of these Dundry Plewrotomaria,
»s, being all the evidence available.

the character of the matrix of specimens in the Bristol Museum, in this as

Vol. 52. ] ON THE UPPER PORTION OF DUNDRY HILL. 705

VIL. Remarks on THE IMPORTANT FEATURES OF THE
Dunpry SrrRaTA.

Some of the more striking features of the Dundry rocks call for
special notice on our part ; and with these remarks we shall have a
few words to say about the contemporaneous deposits in other
districts which are comparable with those of Dundry.

(1) The Marlstone Rock.

The first intimation which we had of the presence of the
Marlstone Rock at Dundry, or rather of the existence of a deposit
laid down during the spinati hemera, was in receiving from a quarry-
man a very good specimen of Pleuroceras aff. nudum (Quenstedt).
This man said that it came from the ‘ Ironshot Oolite’ in one of the
quarries on the hilltop: it certainly came from an ironshot oolite ;
but the colour and softness of the matrix showed that it was not the
Ironshot Oolite,—the rock deposited during the Sauzez hemera.
Further, the specific and generic determination convinced us that
the species lived contemporaneously with Pleuroceras spinatum.
How or where the quarryman obtained it we know not, and we
have never been able to learn. We then knew of no Marlstone
exposed at or near Dundry itself; and we know of none now to the
west of the main road.

Since then we have found Marlstone Rock ; first at Maes Knoll on
the western side of the camp,’ towards the base of the steep escarp-
ment, well within what is marked g 5, Inferior Oolite, in the Geolo-
gical Survey map. Next we found the rock well shown in a
farmyard by the side of the road at Kast Dundry; and here again
the line for Inferior Oolite on the Survey map is carried well below
the Marlstone outcrop. Further, the Marlstone Rock crops out
on the hillside below Watercress Farm, and it has been disclosed
in field-drains opposite the Rookery. On the northern side of the
escarpment from New Down Lane by East Dundry to Maes Knoll,
it is shown at various points in the fields—often slipped or tilted
blocks—and the ‘ bifrons-beds’ are occasionally shown resting upon
it (see Section VIA. p. 684). Immediately west of the corner of
the little spinney south-west of Maes Knoll Tump the Marlstone
Rock is well shown as a massive bed 2 feet 10 inches thick; and
the same bed, as slipped blocks, is seen again for some distance along
the southern side of the spinney. Yet again, in the lower part of
this wood it is exposed in several places in situ, and once more
near the base of the escarpment 70 yards east of the spinney.
For the sections of these latter exposures see p. 686—Section of
Maes Knoll. In addition to these places we have found outcrops
of the Marlstone Rock at several other points, but only in the

1 It was a brown ironshot stone and was conglomeratic, containing derived
lumps —among them a blue stone with crinoids. It yielded belemnites, and
what was determined as Pseudopecten equivalvis.

706 MESSRS. 8. 8S, BUCKMAN AND E. wiLson _[ Nov. 1896,

eastern portion of the hill, that part which lies east of the Chew
Stoke Road.

The general characters of the rock may be stated as follows :—
Coarse, yellowish-brown, ironshot oolite—the oolitic feature almost
universally present, but most strongly developed in the upper
portion of the rock,—distinguished by the presence of the species
noted in our faunal lists.

It was probably the ironshot-oolitic character which deceived the
officers of the Geological Survey, as it has doubtless misled geologists
subsequently ; but the fossil evidence is clear, moreover it is fairly
abundant, and so too are the exposures about the eastern part of
the hill. Yet, as a matter of fact, round the greater part of the hill
the boundary-line of the Inferior Oolite on the Survey map is
carried well below the outcrop of the Marlstone—just as far below,
in fact, as would have been correct had the Marlstone been actually —
‘the Ironshot Oolite’ of the Sauzer hemera.

(2) The Blue Ironshot-beds.

In order to be precise we have called the hard deposits lying upon
the Marlstone, or separating the upper and lower clays where the
Marlstone is absent, ‘the Blue Jronshot-beds,’ from the noticeable
characters of the matrix ; but colloquially we have spoken of them
at times as ‘the Cephalopod-bed, because in part these deposits are
contemporaneous with part of the Cotteswold Cephalopod-bed, at
other times as ‘ the bzfrons-beds,’ because of the presence of Hildo-
ceras bifrons.

The series of deposits forming the so-called ‘ Blue Ironshot-beds’
were exposed by excavations at the western end of the hill and at
Maes Knoll; and at many other places on the flank of the hill these
deposits have been found, recognizable by their peculiar matrix
and the contained fossils. At the western end the strata are very
thin, but nevertheless furnish evidence of deposits laid down during
the following hemere:: falcifert, bifrontis, striatuli, fallaciosi—so that
there is wanting any deposit made during the variabilis hemera.

At Maes Knoll the beds are thicker; but it is evident that the
deposit is of a fairly uniform and persistent thickness throughout
the range of the hill. At the latter place a very good section was
obtained by excavation, showing a clear sequence of deposits during
the hemerz noted above and during that of variabilis as well ; in fact
the deposit of this latter hemera is very distinctly marked by fossils.
As to the other beds, perhaps it would be more correct to say that
the deposit laid down during the bifrontis hemera is not present
at Maes Knoll, but that it has been removed and redeposited during
the variabelis hemera.

As to the correspondence of this bed or series of beds with those
‘of the Cotteswolds, it may be seen in Table VI., facing p. 704; but
we may note that the deposit separating the beds of the falczfers
and striatulc hemerz at Maes Knoll is only 18 inches in thickness,

Vol. 52. ] ON THE UPPER PORTION OF DUNDRY HILL. 707

partly, no doubt, owing to the break-up of the difrons-bed and
redeposition, whereas the deposit during the same length of time at
Frocester Hill, ascertained by 8. 8. Buckman by some recent measure-
ments, is as much as 264 feet in thickness,

With regard to the rest of the Cephalopod- or Blue Ironshot-bed of
Dundry Hill, it may be noted that only the deposits of the striatulz
and dispansi hemere are contemporaneous with the Cotteswold
‘Cephalopod-bed’; that they are equivalent only to the lower
portion of that bed, because the Cotteswold Cephalopod-bed shows
deposits made during the following hemerx: striatult, dispansi,
Dumortierie, Moorei, aalensis—so that it is equivalent in point of
time to the Blue Ironshot-beds (upper part), the Dumortieria-beds,
and the basement portion of the limestone series of Dundry Hill.

(3) The Dumortieria-beds.

It is certainly rather singular that the inappropriate nature of
the term ‘ Midford Sands,’ from a lithological point of view, should
be shown by a locality so close to Midford as is Dundry Hill. The
distance from Midford to Maes Knoll is only 103 miles; yet
the deposit which would be called ‘ Midford Sands’ at Dundry is
a clay called by us the ‘ Dumortieria-beds,’ resting upon a thin
ironshot limestone, and this latter deposit is contemporaneous with
some 30 feet of the lower portion of ‘ the Sands’ at Midford.

With a thickness of some 50 to 60 feet the clays of the Dumortieria-
bed are to be found all round Dundry Hill, immediately below the
Limestone Series or so-called ‘ Inferior Oolite’; and they may be
known by such surface-indications as fruit-trees, springs of water,
and soon. They yield a good pasture, and thus, instead of the fir-
trees and waste land which occupy the sandy slopes of the
Cotteswold Hills, there are, at Dundry, grass-fields and occasional
orchards at about the same geological level.

The Dumortieria-beds are, in point of date, contemporaneous with
the middle portion of the Cotteswold Cephalopod-bed, and, judging
by the evidence at North Stoke’ near Saltford, with the upper part
of the Midford Sands.

But we must note that the term ‘ Midford Sands’ has been used
in two different senses. It is employed in a wide sense to embrace
various non-contemporaneous sandy deposits laid down from the
latter part of the bifrontis hemera until the opalini hemera in-
clusive; while in its restricted sense it is only a local name for
certain sandy beds in the neighbourhood of Bath, of the date of the
dispansi hemera so far as the earlier part is concerned, and the
later portion—judging by the evidence of North Stoke—of the
date of the sueceeding Dumortierie hemera. ‘Taken in a restricted
sense, the Midford Sands are well represented at Dundry by a
thickness of 50 to 60 feet of strata,—which is very different from
what our predecessors have stated; but at Dundry they cannot be

1 North Stoke is 7 miles eastward from Maes Knoll.

708 MESSRS, S, S. BUCKMAN AND E. wILson _[ Nov. 1896,

called ‘Sands’ at all—they are truly clay. These beds are un-
doubtedly the Upper Lias of some previous observers, while the
Terebratula Eudesi and concavum-beds were their ‘ Midford Sands.’

As to the thickness of the strata of the Dumortrerie hemera at
Dundry as compared with the Cotteswolds, we find the opposite
to what obtained in regard to the last comparison—the variabilis-
beds ; but it is not so pronounced. Dundry shows 50 to 60 feet, as
against the Cotteswold deposit, which is often only a few inches in
thickness, but does reach to as much as 8 feet at North Nibley.

The sequence of ammonites found to obtain at Dundry Hill from
the time of bifrons to that of Dumortieria is just the same as that
which was first pointed out by one of us!, and has since been proved
over so large a part of Europe.”

(4) The Strata of Aalenian Age.

At Dundry there is evidence, in a bluish stone at the base of the
so-called ‘ Inferior Oolite’ limestone, of a deposit containing ammo-
nites of the Grammoceras-aalense type, contemporaneous with
the upper part of the Cotteswold Cephalopod-bed. We have, how-
ever, no very definite evidence of any deposit during the opahn
hemera, nor during the scisst hemera, which is so noticeable in the
Cotteswolds as the ‘“‘ Sandy ferruginous limestone.”

At Dundry we have evidence of the deposit of rock during the
Murchisone hemera, but we have littie testimony as to any deposit
during the bradfordensis hemera; this is partly owing to the want
of exposures and the intractable nature of the rock. The deposits
of the date of Murchisone (and perhaps bradfordensis) are thin,
like the contemporaneous deposits in Dorset, whereas in the Cottes-
wolds the contemporaneous strata attain a very great thickness
(150 feet or more), and their subdivisions can be noted easily.

(5) The Strata of Bajocian Age.

The presence of the Sonnimia fissilobata-ovalis-type of ammonite
at once marks a certain horizon at Dundry as contemporaneous

1 §. S. Buckman, ‘On the Cotteswold, Midford, and Yeovil Sands” Quart.
Journ. Geol. Soc. vol. xlv. (1889) p. 440; extended and added to in ‘ Monograph
Inferior Ool. Ammonites,’ Pal. Soc. vol. xliv. (1890) p. 164; and ‘On the
Jurense Zone,’ Journ. Northants Nat. Field Club, vol. vi. (1890), list of species
peculiar to the different divisions.

2 Louis Brasil, ‘ Sur le Lias supérieur et le Bajocien de Tilly-sur-Seulles et
Feuguerolles,’ Bull. du Laboratoire de Géol. de la Faculté des Sciences de
Caen, vol. ii. p. 167, 1893; ‘Les Divisions de la Zone a Lytoceras jurense en
Normandie,’ Bull. Soc. Linn. Normandie, ser. 4, vol. ix. fasc. 1, p. 34, 1896;
also ‘Remarques sur la Constitution du Toarcien supérieur dans le Calvados,
ibid. fase. 2, p. 147, 1896.

Emile Haug, ‘ Jurassique,’ La Grande Encyclopédie, p. 322, Paris, 1895.

Jules Welsch, ‘ Sur la Succession des Faunes du Lias supérieur et du Bajocien
inférieur dans le détroit du Poitou,’ Compte-rendu de |’Académie des Sciences
de Poitiers, 1895.

Chartron et Welsch, ‘Sur la Succession, etc., dans les environs de Lugon
(Vendée), zbzd. Aug. 1896.

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 709

with the lower part of the fossil-bed at Sandford Lane near Sher-
borne, and with the Gryphite Grit of the Cotteswolds. The middle
part of the Sandford Lane Fossil-bed contains numerous species of
Witchellia ; similar species of the same genus are found at Dundry
above this Sonninia fissilobata-ovalis horizon, in a bed of different
matrix ; and they are found in the Cotteswolds in a bed lithologically
different from, and some 12 to 25 feet above the Gryphite Grit
(jissilobata-ovalis): so that the correspondence in this case is very
noticeable. Then the upper part of the Sandford Lane Fossil-bed
contains a peculiar fauna—consisting of Sonninie of the propin-
quans-type, high-keeled species noticeably different from fissilobata
—and ‘ Stephanoceras’ Sauzei, or contractum; and the same suite
of fossils is found at Dundry above the Wotchellia-series in an
unmistakably different matrix. No deposit of this date can yet be
definitely stated to have been found in the Cotteswolds, yet at Cleeve
Hill there is, above the Wetchellia-grit, some 25 feet of rock
which it is reasonable to suppose was laid down during the Sauzei
hemera, simply because of the position which it occupies in the
stratigraphical sequence.’

Above the Ironshot Oolite—the deposit of the Sauzet hemera—
there is at Dundry a non-sequence, just as there is at Cleeve Hill,
and at Sandford Lane, near Sherborne; but at Oborne, near Sher-
borne, are found the deposits laid down in this interval; and these
are noted in Table VI., facing p. 704.

(6) The Strata of Bathonian Age.

Of the date of the deposit which follows the stratigraphical gap
in the sequence of the Dundry rocks we have a certain amount of
evidence from contained fossils: it was laid down during the
Garantiane hemera. Therefore it is contemporaneous with the
Upper Trigonia-grit of the Cotteswolds, which also follows the
stratigraphical gap so noticeable in that district; and it is con-
temporaneous with the Freestones of Sherborne (Dorset).

Of the exact date of the remaining Dundry deposits we have not
much evidence. We have, of course, that of their position in the
stratigraphical sequence, and we have the brachiopod evidence of
the Coralline beds. The inferences to be drawn therefrom we have
stated on p. 680, ete.

In the Freestones and Coralline beds, but in the latter more
particularly, there is a considerable amount of siliceous matter
which no doubt adds materially to their hardness. There is
chaleedony with geodes containing quartz-crystals, as well as
incrustations of beekite.

(7) The Geographical Extent of the Ironshot Oolite.
The Ironshot Oolite has been found by us only at the nortbern
and southern main-roadside quarries, at Rackledown, at East

' §. S. Buckman, ‘The Bajocian of the Mid-Cotteswolds,’ Quart. Journ.
Geol. Soc. vol. li. (1895) p. 461.

710 MESSRS, S. S. BUCKMAN AND E. witson _—[ Nov. 1896,

Dundry, and 3 mile to the east thereof. It is known to be absent
at Clements’ Yard, Barns Batch Spinney, and Maes Knoll. There-
fore in a westerly direction it has been removed entirely in 3 mile
from the main road, and in an easterly direction it probably fails
in about # mile east of East Dundry. North and south it is cut
off by the escarpment. Consequently the Ironshot Oolite occupies
an area in the middle of the hill only, and its extent cannot be
more than 1? miles long (from east to west) and about 1 mile wide
(from north to south). The reason for the limited east-to-west
extension of the Ironshot is in all probability denudation soon after
its deposition, to which the flat top of the Ironshot itself bears
witness ; and the planed-off top of other beds where the Ironshot
is not present also tells the same tale. The theory of a limited
area of original deposit in regard to the east-and-west extension
would involve the hypothesis that the sea-bottom of the western
portion of the hill was elevated after the deposition of the Lower
White Ironshot (Sonniniw hemera).

(8) The Geographical Extent of the Freestone.

This is a matter of considerable economic importance. We are
able to show that the Freestone thins away very rapidly, and also
loses the freestone character, as we proceed from Dundry Church
eastward—the Northern Main-road quarry (Section LY.), and south-
eastward—the Southern Main-road quarry (Section [X.). These beds
thin away and deteriorate so rapidly that it is very doubtful whether
workable building-stone of good quality would be found 7 mile east
of the church. Westward, on Dundry Down, tke old workings
for freestone are very numerous, occupying a considerable area,
and it is probable that nearly all the good stone has been obtained
in that direction. There remains, however, the ground east of the
Down and south of the church, an area about equal in extent to
that which has been worked for stone; and this may certainly be
expected to yield freestone of good quality. Farther south, in
the direction of Barns Batch, there is a considerable thickness of
stone, but its quality would seem to be inferior to that of the
Freestone proper. It is unfortunate that for want of suitable
exposures we are not able to give more precise details concerning
the construction of the hill between the Winford road and Barns
Batch ; but itis obvious that the area over which workable freestone
is likely to be found is a very restricted one. Our investigations
indicate that it certainly extends very little to the east or south-
east of the village, and certainly is wholly confined to the portion
of the hill westward of the main road.

Concerning the qualities of the Dundry Freestone, the following
works may be consulted :—

Lioyp Morean, Prof. C., ‘On Bristol Building-Stones,’ Proc.
Bristol Nat. Soc., N.S., vol: v. pt. ii. pp. 98, 102, 104.

Hout, Prof. E., ‘On the Building and Ornamental Stones of

Woly.5 2.2] ON THE UPPER PORTION OF DUNDRY HILL. 711

Great Britain,’ London, 1872, p. 209; and p. 318 gives the weight
of a cubic foot of Dundry stone.

For analyses of the Dundry Freestone see

Vortcker, Prof. A., Journal of the Bath and West of England
Agric. Soc., New Series, vol. vi. p. 223; Mem. Geol. Surv. vol. ii.
(1848) pt. 2, p. 688.

IX. Tue Basocran Denvpartton.?

Nowhere at Dundry Hill is the sequence of Bajocian strata com-
plete; there is, even at the main-road quarries, where deposits have
been laid down during the greatest number of hemere, a break in
their sequence, so that the succeeding bed rests non-sequentially
upon the planed-off surface of the Ironshot Oolite.

The portion of the Dundry strata which suffered least from
Bajocian denudation is that lying between the main road on the
west, and East Dundry and Rackledown on the east. Westward
of this the Bajocian denudation bas removed two important fossili-
ferous beds, namely, the Ironshot Oolite and the Witchellia-bed.
Fast of this area there are unfortunately no exposures until Maes
Knoll is reached, when the effects of denudation are very striking.
The Ironshot and all the limestone-beds which underlie it at
Dundry have been removed; and further denudation must have
taken place here in Bathonian time while deposition was going on
quietly at the western end of the hill, for at Maes Knoll there is a
conglomeratic bed of the date of the Garantiane hemera containing
shells of the Dumortierie hemera.

Farther eastward, at North Stoke, a similar deficiency in the
stratigraphical sequence occurs, due in part at any rate to Bajocian
denudation. ‘There the strata of the Garantiane hemera rest upon
about 8 feet of sands deposited during the Dumortierie hemera. A
similar non-sequence of deposits is found at the Barrow Hill, and
at Midford, near Bath. Then, in a northerly direction, from Bath
to Cheltenham, the Garantiana-bed is still found resting non-
sequentially on an earlier deposit; but the gap in the sequence
decreases as the distance to Cheltenham lessens, until near that
town strata contemporaneous with the Witchellia-bed of Dundry are
once more found beneath the deposit of the Garantiane hemera.”

South-east of Dundry, however, some striking facts concerning
non-sequence of deposition were obtained. At Wellow, near
Radstock, 10 miles E.S.E. of Maes Knoll, the deposit of the Garan-
tiane hemera rests in some cases upon clay of a pre-falcifert

1 Tt should be noted that the term ‘ Bajocian denudation’ does not mean
denudation of rocks of Bajocian Age, which might have happened at any date,
but a denudation (of any rocks) which was effioted during the Bajocian Age.
In the present case, so far as Dundry is concerned, the denudation doubtless
began towards the close of the Bajocian Age, and ended at the beginning—
before the second hemera—of the Bathonian Age. But there is evidence at
other places that it continued during the second hemera of the Bathonian Age.

2 §. S. Buckman, ‘ The Bajocian of the Mid-Cotteswolds,’ Quart. Journ. Geol.
Soe. vol. li. (1895) p. 416.

712 MESSRS, 8, 8. BUCKMAN AND E. witson _[ Nov. 1896,

hemera in date; but in other cases pockets of later deposits have
been left to tell the tale of what was once laid down there. We
visited the section and made the following observations, which may
be of interest for comparison with Maes Knoll :—

Section XI.—Wellow. First cutting on the Somerset and
Dorset Railway towards Radstock.

ft. ims. || ft. amg:
1. Cream-coloured, crystalline, coarse-
grained limestone, Terebratula globata
(Cotteswold type), about 5 feet up.
Several feet thick.
GaranTiAN&. 2. Yellowish, very strongly ironshot stone,
the grains not so large as in bed 5.
Acanthothyris spinosa, Nerinea Guiset.
Small Astarte and lamellibranchs ... O 4
3. Hard iron-specked limestone with iron
markings, irregularly but firmly
cemented to bed below................-. 0 2

Dunortien1z? 4. A greenish-pink, arenaceous stone,
from 1 to 3 inches in thickness, much
bored by Lathod oma .200i-0.:0cenasehame 0 3

Dispansi? 5. Yellowish, very strongly ironshot stone.
to BIFrRonNTIs. Hildoceras bifrons, Grammoceras

OCT NLENSE. Adah inn dad edenebics toneuoKes Laake QO
6. Ironshot, bluish-grey limestone with
Hildoceras bifrons, Dactylioceras,

Ethynchonella cf. Mooret ......s2.0.006 0 4

Fatorrert. 7. Pinkish, argillaceous stone with iron
specks containing ammonites indi-
cative of the falciferum and perhaps
bijroms NOLIZONSe.ca-teeeteeeee ners 0 8
8. Blue clay, visible in the next cutting
towards Radstock?............ about 209 ie

At the place where the section was measured Beds 3 & 4 were
not found, so that Beds 2 & 5, both remarkable ironshot beds, came
into actual contact, with the result that the same block of stone, only
a few inches thick, yielded Hildoceras bifrons and Acanthothyris
spinosa. The statement that these two species occurred together
would have been deemed incredible, although it is true enough in
the present case. Their occurrence together does not, however, prove
that they were contemporaneous; yet such a supposition has led
to much futile argument about inosculation of zones. Really the
explanation in this caseis simple. Itis known from the evidence of
many other localities that an immense interval of time must have
elapsed between the existence of Hildoceras bifrons and the time
when Acanthothyris spinosa lived. Therefore whatever deposit
accumulated above the bed with Hildoceras bifrons must have been
removed down to that; level before the deposit of the Acanthothyris-
spinosa date was laid down. ‘Thatthere was such removal is shown
in parts of this cutting, for, as stated above, the full sequence was

1 There is no evidence as to the date, but presumably this is the same clay as
that proved at Maes Knoll, Section VII s, No. 17,

Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 713

not found where the section was measured, but the missing beds,
Nos. 3 & 4, were found 35 yards eastward. Still farther east all the
beds numbered 3 to 7, inclusive, were absent, and Bed 2 was sepa-
rated from Bed 8 only by a thin band of a blackish dense stone. To
the west in thesame cutting a somewhat crystalline stone, presumably
representing Beds 1 & 2, rests on about 4 inches of the falciferum-bed
No. 7; so that here Beds 3 to 6 are absent. Still farther west, and
also in the next cutting towards Radstock, Beds 3 to 7 have but
narrowly escaped total denudation, and they remain as relics of the
destruction which took place prior to the deposition of the strata
of the Garantiane hemere.

X. Tor WaATER-BEARING BEps or Dunpry HItt.

Springs issue at two principal levels, and occasionally at two or
three others, on the upper slopes of Dundry Hill. The chief level
for large springs is at the top of the shales of the Dumortieria-
beds, the water often welling forth in streams of considerable
volume and of great persistence where the Aalenian limestones
rest upon these impervious argillaceous strata. This is the chief
water-bearing bed of Dundry village; in fact, it is because the
Dumortieria-beds are clay that the houses of Dundry occupy their
present position: had the Dumortieria-beds been sands, the water-
bearing surface would have been nearly 50 feet lower down than it
is now.

The level next in importance for springs is the base of the Marl-
stone Rock, from which water is thrown out at various points along
the eastern portion of the northern escarpment and also on the sides
of the valley below East Dundry.

At certain points on the western side of the hill, where the Marl-
stone is absent, or, if present, exists in so fluctuating and attenuated
a form as to have hitherto escaped detection, springs occasionally
break out from the ‘ b:frons-beds’: the Elwell spring, south of
Castle Farm, is an example. The ‘Cephalopod-bed,’ or ‘ difrons-
beds,’ also often gives out small springs on the hillside, both on the
northern and the southern escarpment. Moreover, small springs
occasionally break out from the grey sandstones in, and especially
near the base of, the Dumortieria-clays: several of the drinking-
pools for cattle are thus supplied. Such is the source of the small
spring just above the Elwell spring; of another spring at the old
and dismantled Pickwick Farm, west of Maes Knoll; while until
recently there was a small spring visible in these beds on the right-
hand side of the main road, immediately south of the Butchers’
Arms.

Another occasional level for water is formed by the shales with
Terebratula Eudesi—that is, at about the junction of the strata of
Bajocian age with those of Aalenian date, one of these being just
below Castle Farm on the western escarpment.

Some of the smaller springs dry up altogether in the middle of
summer, or in very dry seasons; but the larger springs of Dundry
Hill are remarkably persistent.

714 THE UPPER PORTION OF DUNDRY HILL. [ Nov. 1896,

XI. Tar Map or Dunpry Hitt.

With this communication we present a geological map of the
different deposits and their superficial extent as found by us to
obtain at Dundry Hill. As the map of the Geological Survey shows
round so very much of the hill the Marlstone of the Middle Lias,
and even beds below that, coloured as if they were Inferior Oolite,
our map is, we consider, of value in that it amends the official
document. But we claim that it is of importance in another respect.
That different lithological conditions prevailed at the same time in
closely contiguous areas is an accepted fact; and as a consequence,
paleontological divisions do not coincide with divisions founded on
lithological characters, as one of us (8. 8. Buckman) has repeatedly
urged in a series of papers on the Jurassic rocks. We show in the
present paper that this non-agreement between the palzontological
and the stratigraphical methods obtains at Dundry compared with
surrounding areas; and therefore the divisions accepted by us in
our mapping are based upon purely paleontological lines. We
present therefore what is really the first Jurassic map of any area
in which such divisions have been represented. The divisions which
we have adopted are as follows; and in order that they may be
compared with the divisions adopted in their maps by the officers
of the Geological Survey, we place the two side by side :—

Quenstedt’s Divisions | The present Divisions

in Germany (chronological, based The Geological Survey Divi-
(stratigraphical and solely on palzonto- sions (stratigraphical).
palzontological). logical evidence).

From the upper portion
of the Interior Oolite
up to the Kellaways
Rock inclusive.

Brauner Jura Z .......+.
Brauner Jura eé ......... Bathonian
Brauner Jura 6 (pars).

Brauner Jura 0 (pars).

| Bajocian Inferior Oolite (pars).

Brauner Jura y ..-......

Brauner Jura @ ......... { Inferior Oolite (pars).

Brauner Jura a ......... Midford Sands (pars).

Midford Sands (pars).
Upper Lias.

Schwarzer Jura Z ......
Schwarzer Jurae ......
Middle Lias.

Jura 6, etc.| Ch thi
Schwarzer Jura 0, etc arma Upper part of Lower Lias.

Sec. Lege

.

. °

Th iat
. oO
. ony

(a a lesa
ay / he es Se
SSS a T/L ie
ae ee Saas
*. a as Soe 2 Ee Se ES a BS Ed ee ae x
Steet ae te ie

MEADE FARM thonian A

wee
sereener wee
seen cceet teasers
*. v a )
. OF '* : Oe
*, . a 7
- . aeteee 5 m4
5 . or
. . . . .
a, tees, ans foo?
° ¥p. °
. . : ee .
° : o *s, .
. : A ener 'e .
. oJ, de**e hae’ ooe .
* . neg ** a he aaeee® . *.
. wo + .
. A 7 .
*, .. BNA SS PN ae Niwa *
. sey attee 2 ” %., 5
- . . ". . 5
* : . - ;
° S CET PT
. SeretieD Va
*. Sresee Chalo
Oe, oh On

Marlstone Biock

| ta
i Tl i i Ee

LTT rs. ras >
ERCRESSA):

Y)

ge Ws Aalenian Age EES Toarcian Age

[Seale : 2 inches = 1 mile. ]

=== DUNDEY Si

By E.Wilson.

Q MODEL FARM

i
NORTON doped
MALREWAR

[oF GEOLOGICAL MAS SS

400

""SéeVIb.**,

%
Aa

CourRT

Note.—The geological boundaries were placed on the 6-inch map of the Ordnance Survey, on which this sketch-map is based.

716 MESSRS, 8. 8. BUCKMAN AND E, WILson _ [ Nov. 1896,

As a matter of fact, so far as Dundry is concerned, the line which
we draw to mark the commencement of deposition in Aalenian
time should coincide with the line which the officers of the Geological
Survey have drawn as the base of the Inferior Oolite. That there
is not always such coincidence is due to the error about the
Marlstone already alluded to (pp. 683, 706). Then the area enclosed
by our Bathonian-Aalenian lines represents what would be called
‘Inferior Oolite, 75, so far as Dundry Hill is concerned; and the
limits that we have laid down may be regarded as =‘ Inferior
Oolite’ planned to the best of our ability.

As to what our terms ‘ Aalenian,’ etc., represent, the reader is
referred to Table IV., facing p. 696. Of course, only the commence-
ment of the Bathonian age is now represented by deposits at
Dundry. The deposits of Bajocian age there are so incomplete and
so meagre that we have not attempted to map them separately, and
therefore the Bajocian beds are, as a matter of fact, marked
Aalenian; but their outcrop-area is so small that this is not a
matter of importance.

Our method of procedure in regard to the mapping was as
follows :— We paid two or three visits to the hill in company, and
decided the limits of our divisions at certain of the more important
points. ‘The mapping. of the intermediate country was done by one
of us (EK. Wilson) alone, tracing the deposits of the different hemeral
series round the hill as opportunities for the numerous necessary visits
arose. Then one or two of the exceptionally difficult and doubtful
portions where exposures are wanting, and everything was hidden
beneath a continuous cloak of grass, were re-surveyed in company.

Owing to a deficiency of exposures or of any clear physical feature,
it has been found impossible to determine with precision the limits
of the Dumortieria- to spinati-beds round the Rackledown projection,
for some little distance along the southern side of the escarpment
between East Dundry and Maes Knoll, and also for some little
distance east of the drinking-trough on the Chew Stoke road, 3 mile
east of Dundry village, on the northern side of the plateau; and
the lines drawn cn our map for these portions of the area must be
looked upon, therefore, as to a certain extent conjectural.

In the western portion of the hill—z. e. west of the main Chew
Stoke road—owing to the absence or non-appearance of the Maristone
Rock, the Toarcian base-line had to be defined by the bzfrons-bed,
which, being too insignificant of itself to form an appreciable
surface-feature, made it impossible for us to do more than draw
in this line to a certain extent conjecturally : the chief evidence for
it being furnished by the presence, at a level of about 50 feet below
the base of the Aalenian Series, of the bzfrons-bed in springs, road-
cuttings, hillside scars, and our special excavations made at the
western end of the hill.

Concerning the natural features of the surface-configuration of
Dundry Hill, the following remarks may be made :—

The edge of the hill, which may be as much as 109 feet below
the highest ground on Dundry, is defined by rocks of Bathonian age

Lad

Vol. &2,] ON THE UPPER PORTION OF DUNDRY HILL. 117

forming a steep and well-marked escarpment on the northern and
western faces of the hill, and a very bold one above the valley west
of East Dundry and round the Maes Knoll promontory ; but this
feature is much less clearly defined, and often quite indistinct, on the
southern face of the eastern portion of the hill and round the Rackle-
down projection. The greater hardness of the rocks of Bathonian
age (to which date, it is to be remembered, we assign the Freestones
of Dundry), relatively to the underlying deposits, gives a steeper
slope to the upper edge of the escarpment, so that we generally find
a projecting brow of these rocks above the somewhat softer strata
of Bajocian-Aalenian date. It is often hard to define with pre-
cision the base of the ‘ Upper (Bathonian) beds,’ partly owing to
the limited number of exposures at the right level, and partly
because much of their rubble has travelled some distance down
the hillside, concealing the outcrops of the underlying strata.

The strata of the Bajocian-Aalenian ages, which are also a variable
series, owing in part at any rate to pre-Bathonian denudation, form,
where they are present, the lower and generally less steep upper
portion of the escarpment, or even a slight terrace.

The Dumortieria-clays, deposited during the Toarcian age, are
readily worn back,and hence they usually give avery steep, sometimes
almost mural slope beneath the overlying protecting beds. Slopes
of this kind are tound beneath Dundry village, and around the Maes
Knoll promontory.

At a distance of from 50 to 60 feet below the lower limits of the
strata of the Bathonian-Aalenian ages, a second lower and minor
escarpment or terrace may frequently be noted. This escarpment is
determined either by the Marlstone Rock, by the ‘ b¢frons-bed,’ or by
some hard beds in the lower portion of the Dumortieria-clays a little
above that bed. The feature made by the Marlstone Rock is often
well defined in the eastern portion of the hill, e.g. at various points
along the northern escarpment east of the northern end of Newdown
Lane, directly beneath East Dundry, and around the upper portion
of the East Dundry Vale.

Below the Marlstone terrace the ground formed of soft clays of
the Charmouthian age, with few hard beds in them, slopes away at
a much gentler angle than the clay ground above the Marlstone
slopes down to that rock.

It may be noticed that the beds of Dundry are synclinal, espe-
cially from east to west. This synclinal feature probably accounts
for the lower level at which the strata of the Bathonian age lie near
East Dundry compared with Maes Knoll. On the edges of the
escarpments there is evidence of local faulting or slipping over, as
for instance at Barns Batch, and the northern main roadside quarry ;
while dip-slope towards the escarpments, and not any exaggerated
thickness of the beds, probably accounts for the much lower level
which the strata of Bathonian age (Coralline, etc.) cccupy on the
edges as compared with the middle portion of the hill—as, for
instance, the northern and north-eastern margin of the main hill, and
the eastern slopes of the Rackledown spur.

Os

718 MESSRS. 8. S. BUCKMAN AND FE. witson ___[ Nov. 1896,

(1) Comparison of the Geological Survey Map’ with the
one here presented.

The Geological Survey map represents at Dundry only Inferior
Oolite resting upon Lower Lias. The boundary-line which we shall
have to notice is that drawn separating the deposits so classed.
Beginning at the main road on the northern flank of the hill, and going
westward, the Survey’s boundary-line of Inferior Oolite coincides
with our own (beginning of deposition in Aalenian age), and is
drawn at the top of the Dumortierza-clays, along by the village and
‘The Grove,’ until about 250 yards north of Castle Farm, when it
strikes off to the top of the ‘ Cephalopod-’ or ‘ bifrons-beds’; and at
Castle Farm it is about 150 yards outside our line. It continues on
or a little below this horizon round the southern flank of the hill to
Rackledown Farm, when it drops below the Marlstone—as much
below, in fact, as it ought to be if the Marlstone were really the
Ironshot Oolite of the Sauzei hemera. It continues at this level
round both sides of the East Dundry Valley, with the result that the
Survey base-line of Inferior Oolite is, at the head of the valley, as
much as 650 yards outside ours.

Their boundary-line then continues to run on this infra-Marlstone
level to Maes Knoll, where in drawing our line we differ from the
Survey to the extent of about 100 feet in vertical thickness, and in
some places, as at the north-eastern corner, to the extent of about
250 yards in horizontal distance.

From Maes Knoll their boundary-line continues along the northern
flank of the hill on the infra-Marlstone level until it approaches the
main road whence we started, when they show a lengthy northward
prolongation of ‘ Inferior Oolite’ by the eastern side of the bend in the
main road. This projection is not only some 400 yards outside the
boundary of what they call Inferior Oolite across the road, but it is
even some 250 yards outside what we take to be the horizon of the
Marlstone.

It will thus be seen that, except along the nowthene flank of
Dundry Hill, to the west of the main road, ‘the Survey have mapped
far too ereat an area as Inferior Oolite, and as a consequence have
given too great a vertical thickness to the ‘Inferior Oolite” The
latter result of course obtains more at Maes Knoll than elsewhere,
because there only a very thin capping of strata of Bathonian age
is left to represent the ‘ Inferior Oolite.’

(2) Comparison of Sanders’s Map? with our own.

Commencing at the main road, as before, Sanders shows the base of
the Inferior Oolite at the top of the Marlstone ; then the line rises,

' Sheet XIX., ‘Geological Information revised, and Penarth Beds surveyed,
by H. W. Bristow, H. B. Woodward, W. A. E. Ussher, and J. H. Blake, 1867—
1871. New edition. Published May 1873,’

2 Sanders, William: ‘Coalfields of Bristol and the Country adjacent
geologically surveyed.’ Folic manuscript, 1562. Map published on the scale
of 4 inches to 1 mile; republished by Lavars & Co,, Bristol, on the scale of
1 inch te 1 wile.

Vol. 52. | ON THE UPPER PORTION OF DUNDRY HILL. 719

and is carried along about the middle of the Dumortieria-beds all
round the hill until it meets the main road at the south, by Elton
Farm, when it drops to the Marlstone level. Thence it is carried at
this horizon until a little east of Watercress Farm, on the southern
flank of the East Dundry Valley. Here it begins to rise gradually,
and at the head of the valley, at the Butchers’ Arms, it reaches the
top of the Dumortieria-beds, so that here it coincides with our
own map and differs seriously from that of the Survey. Returning,
on the northern flank of this valley, it drops to the Marlstone level

just before East Dundry is reached, and along that horizon it is

continued until above Northwick Cottages. Here Sanders’s Inferior
Oolite line makes a large outward bend, as much as 5V00 yards
outside our Marlstone limit. Then it returns to the Marlstone
level, at about the middle of the bend before reaching Maes Knoll,
and is carried at about this level round the hill until the main road
on the northern flankis again reached. It does not show that great
bend at this point which is so conspicuous on the Survey map.

It will be seen, therefore, that Sanders’s map, although of earlier
date, approximates more closely to our own than does that of the
Survey, and that for the western portion of the hill it is generally
only a little outside our ‘ Inferior Oolite’ limit. For the eastern
portion of the hill there are considerable differences between our
map and his, which, like the Survey map, shows far too great an
area as ‘ Inferior Oolite.’

XII. Summary.

The following facts and conclusions have been brought forward
in this paper :-—

1. That at Dundry Hill the sequence of strata laid down during
the Bathonian-Bajocian ages is incomplete, because there is no
deposit to represent the time of the niortensis or Humphriesiant
hemere ; in fact, during these hemere denudation was in progress
at Dundry.

2. That all the strata of the Aalenian and Bajocian ages have been
removed from the eastern end of the hill, so that strata of Bathonian
date (Garantiane hemera) rest non-sequentially upon deposits laid
down during the Dumortieriw hemera.

3. That this removal has been effected by denudation in Bajocian
and even post-Bajocian time.

4, That strata equivalent to what are called elsewhere Midford
Sands, Upper Lias, and Middle Lias (Marlstone) are present in the
hill, the two former attaining a maximum thickness of more than
60 feet, while the Marlstone crops out at many points along the
flanks of the range.

5. That the officers of the Geological Survey have apparently
confounded the Marlstone Rock (an ironshot oolite of the date of the
spinati hemera) with the well-known LIronshot Oolite (of the date

of ei Sauzei hemera), a bed nearly 100 feet higher up.
. That in consequence of this mistake they have, round the
oe part of the hill, drawn the base of the Inferior Oolite as far

720 THE UPPER PORTION oF DUNDRY HILL. [ Nov. 1896,

below the Marlstone as this base ought to have been drawn if the
Marlstone were really the Ironshot Oolite or Sauzez-bed.

7. That the officers of the Survey have mapped as Inferior
Oolite strata which are marked by them elsewhere as Lower Lias,
Middle Lias, Upper Lias, and Midford Sands.

&. That the map of Dundry Hill presented with this paper shows
the superficial extent of the Inferior Oolite to have thus been
greatly exaggerated on all previous maps.

9. That the same sequence of ammonite-faunas obtains at Dundry
as in the Cotteswolds and in Dorset, and hence is similar to that
found on the Continent.

10. That the Sonniniw hemera as a distinct period of time with
its own fauna preceding the Witchellie hemera, as pointed out in
the case of the Mid-Cotteswolds, is confirmed by the researches at
Dundry.

11. Faunal lists of species found at Dundry are given, and their
approximate date of existence is assigned as carefully as circum-
stances permit. To one of these faunal lists certain paleontological
notes are appended, wherein is recorded a new name, Zedlleria
Oppeli, for one of tue forms hitherto called Zeilleria (Terebratula)
anglica, attention being drawn to certain difficulties in the original
description and to the consequent application of the original name.

12. A section of a railway-cutting at Wellow is given for com-
parison with certain Dundry sections, and to illustrate the results
of pre-Bathonian denudation.

Discussion.

Mr. H. B. Woopwaxp objected to the application of the Great
Oolite term ‘ Bathonian’ to the upper beds of the Inferior Oolite.
He pointed out that the Dundry outlier had not been revised since
1845, when the Geological Survey map of the area was published.
The differences between the map of De la Beche, Ramsay, and
others, and that produced by the Authors were not, alter all, very
great.

Mr. E. T. Newzon remarked upon the lists of fossils mentioned in
the paper, which included species characteristic of the Middle and
Upper Lias as well as of the Inferior Oolite. It was evident that the
Authors had detected beds of Middle and Upper Lias age where
they had not before been recognized.

Mr. Marr regretted that the Authors were absent, as the summary
which he had read appeared much more controversial than the
actual paper was. He fully believed in the general accuracy of the
detailed work of the Authors, which no doubt was counter to some
of the work of earlier observers.

lod

Vol, 52. | GLACIAL GEOLOGY OF ARCTIC EUROPE, ETC. 721

40. Noress on the Gractat Grotoay of Arcric Evrorr and its IsuanpDs.
—Part II.’ Arcric Norway, Russtan Lartanp, Novaya ZEMLYA,
and SpirspeRGEN. By Col. H. W. Feripen, F.G.S. With an
meeaunor, by Prot. T..G. Bonnny, D.8c., F.R.S., V.P.G8.
(Read June 24th, 1896.)

ContTENts. Page
1. Proof of Changes of Level in Northern Norway .................. 721
mw Lerrace-making- in Koleuey Island ...2.....5.....0.0cecseneeeeeeees 124
@. uacial Geolopy of the Kola Peninsula .........00..0.....ecesaves 726
Peery el, ANSI Wale Coie rast ca sot ees Cerna sas ce Bate eeesineazoigual ose eoncescey 731
Semper mr CL DATE Pega cee ce tessa Reh dates deiedax'<ovk oc ene sne see 738
SRR ETON eter erent hab eepbang gcper sich ones agsceshncnsassseees 739

1. Proof of Changes of Level in Northern Norway.

So much has been written about the glacial geology of Northern
Norway by great authorities that J should have refrained from
discussing the. subject had I not recently heard a paper” read at a
Meeting of this Society, in which the author suggested that the
terraces in the transverse fiords of North-western Norway would
be perfectly explained by the formation of ice-dammed lakes. The
author, however, admitted that the authenticated occurrence of
marine organisms in these raised beaches would be a conclusive
argument against his views. I have never made any special study
of the phenomena connected with the secular upheaval of Arctic
Norway, for I had always been under the impression that few
geological facts were more generally accepted as well established
than the recent elevation of land in Arctic latitudes, including
Northern Norway. My observations are consequently somewhat
cursory, but I do not remember landing on any of the more con-
siderable islands north of the Arctic Circle, that form the ‘Skjergaard’
of Norway, without noticing traces of recent elevation and deposits
containing abundantly shells of mollusca of the same species as
those that now inhabit the adjacent sea. The same holds good of the
‘ Westeraalen, and I observed last summer a well-defined raised
beach near the settlement of Rissohavn, on the island of Ando, full
of the shells of recent mollusca; this beach was overiain by 4 feet
of peaty soil, in which grew birch-trees.

The lofty chain of the Lofoten Islands has not been buried under
anice-cap. Theirsharply peaked and serrated mountain-tops, rising
from the sea to altitudes between 2000 and 3000 feet, present no
evidence of ever having been overwhelmed by the Scandinavian ice-
sheet. ‘There are, however, unmistakable signs that at one period
of their history great glaciers filled their valleys. The celebrated
Trold Fiord near the western entrance of Raft Sund, the channel
between Eastern Vaagoé and Hindé, is a narrow but majestic fiord with

' For Part L., read Noy. 20th, 1895, see this volume, p. 52.
* Boulger, Quart. Journ. Geol. Soe. vol. li. (1895) p, 494.

722

Fig. 1.— Diagram of Tromsédal terrace, showing the valley when occupied by a glacier.

COL. I, W. FEILDEN ON THE GLACIAL GEoLoGy [ Nov. 1896,

Former sea-level

re ee eee ee Ze SS
eee sees eeeee.C*“eg ES =

Present sea-level

perpendicular walls of rock on both
sides; these, to the height of some
400 feet, are polished and grooved
by the action of ice, but the
mountain-peaks that rise above
the fiord show no signs of glacial
abrasion. Attention has been called
to this by earlier writers, notably
hy the late J. F. Campbell’ and
by Prof. Bonney.” Passing up
Raft Sund, amid some of the finest
coast-scenery of Norway, one cannot
fail to observe the traces on all
sides of former glacial action, espe-
cially on the eastern shores of the
channel. There nearly every valley
descending to the shore-line, now
bright with green birch-woods and
pastures, has the remains of great
moraines at its mouth. Farther
north, around Tromsé, the signs of
recent elevation are common along
the shore-line, and so also the
signs of the retreat and disappear-
ance of glaciers which once filled
the valleys; but I see no evidence
that the mountain-tops on the
mainland of this part of Norway
have ever been covered by an ice-
sheet, even at the time of their
maximum glaciation.

The valley of Tromsodal, on the
mainland opposite the town of

Tromsé, has a conspicuous raised |

terrace (fig. 1) passing across its
mouth, and continued north and
south along the present coast-line.
This terrace must be 4 mile wide at
the mouth of the valley, and there
brick-works are established. In
1894 a good section of this terrace,
some 20 feet in height, was ex-
posed, from which the clay used
in the works was being taken.

' «Frost and Fire,’ vol. i. (1865) nos,
136-137.

? Alpine Journal, vol. iv. pp. 430-436 ;
‘Do Glaciers Excavate ?’ Geogr. Journ.
vol. i. (1893) pp. 481-499; ‘ Ice-Work,
present and past,’ p. 175, London, 1896.

Yal,5 2.) OF ARCTIC EUROPE AND ITS ISLANDS. 723

From base to summit it is a homogeneous mass of blue clay, with
boulders and stones interspersed throughout. There is not a trace
of bedding throughout the mass. As I considered this deposit to
be a typical example of boulder-clay formed under water, I took
advantage of my journey in the neighbourhood last summer to
revisit the spot. A more careful examination showed that the
clay contains ice-scratched stones, and that mollusca are abundant
throughout the bed; examples of Cyprina islandica and Pecten
wslandicus, partially retaining their colour, are common, likewise
stones to which the ‘bases’ of a Balanus are attached. On ascending
the terrace, which at its base is only a few feet above present high-
tide mark, and looking up the valley, one can realize that apart
from its composition it owes its formation to glacial causes. ‘This
terrace is flat on the top and at the outer edge slopes seaward, and
the same on its opposite side looking up the valley. There can
be no doubt that this valley was formerly occupied by a glacier;
and when the land stood at a lower level than it does to-day, the
front of the glacier was in the sea and the terrace was formed by the
material which passed from under the ice, and is therefore a kind
of subaqueous moraine. :

As we sail from Tromsé towards the North Cape, the course takes
us through Kaag Sund and past the island of Arno. The southern
shore of that island is fringed for miles by three great parallel
terraces. I roughly estimate Arno at about 1200 feet in altitude
and the terraces at 50, 100, and 150 feet above sea-level. Their
position on an island exposed to the full force of a stormy ocean is
entirely opposed to the possibility of ice-dams having had any
connexion with their construction. In Mageré Sund, which separates
from the mainland the island whence juts out the North Cape, sea-
worn caves, much above the present sea-level, tell of recent elevation
of the land.

The remarkable terraces in the Porsanger and other northern
fiords of Norway have been noticed by Bravais, Martens, J. D.
Forbes, Chambers, Campbell, Bonney, and others in their descrip-
tions of this part of Norway. ‘The Porsanger is the first of the
large fiords that run into the mainland of Finmark. It is about 18
geographical miles in length. The hills on either side are low,
probably not more than 500 feet in altitude. They have an ice-
planed, ice-smoothed contour. The topographical contrast between
this area and the peaked Lofotens and those around and immedi-
ately south of Tromsé is striking. Tue island of Stor Tamso
lies in the centre of the Porsanger Fiord. Its greatest height is
probably not more than 300 feet; it is about 7 square miles
in extent. Evidently an ice-worn surface, it is entirely or almost
entirely covered with a growth of peat, showing a depth in places
of 8 or 9 feet before reaching the polished underlying rock, which
is a rather felspathic quartz-schist.! Where I landed, the rock,
smooth and slippery, passes with a gentle slope into the sea.

1 See Prof. Bonney’s determination of this rock, p. 741.

724 COL, H. W. FEILDEN ON THE GLACIAL GEoLocy [Nov. 1896,

Our boat ran up this rock as over a sand-beach, while both below
and above the tide-mark the rock is so grooved with glacial striz
that it looks as if they had been made by the keels of boats hauled
over sand which had subsequently indurated, while in reality it is
a very hard quartz-schist. This island is girdled in part by a series
of old beaches rising one above the other to a height of not less
than 100 feet. The highest that I traced looks like a line of ancient
fortification. This is due to the accumulation of peat which has
spread over it, and which, sloping towards the sea, is on the land-side
in many places perpendicular. Where runnels have cut through
this terrace the ancient beach is exposed; in it are fragments of
nullipores identical with the remains that are piled up along the
shore at present sea-level, and these at a little distance look like
accumulations of magnified grains of sago. The presence of the
remains of this nullipore in the higher terraces effectually disposes
of the theory that these beaches might have been the result of
interglacial damming.

The remarkable and extensive series of terraces on both sides
of the Varanger Fiord, which separates Norway from Russian terri-
tory, are well known. My friend Prof. Alfred Newton, who visited
the Varanger forty years ago, kindly gave me the following note
from his journal and that of Mr. W. H. Hudleston, his companion.
They were journeying along the northern side of the fiord, not
far from Vadso. He writes!:—‘ We continued our walk along a
raised beach about 50 feet above high water and 200 yards from
the shore, where lay the bones of a whale that had probably been
stranded there in old times. Each of the whale’s vertebre was
covered with turf. We scratched the ground in places and found
ribs, but I do not remember that we found the head.’

On the little island of Vard6, on which the town is built, and near
the fort from which the island takes its name, is a marine sand-
deposit some 40 to 50 feet above sea-level. I lately took from this
spot remains of seal,” cetaceans, fishes, and mollusca. I might easily
enlarge the list of localities in Arctic Norway which I have visited,
and where similar proofs of recent elevation are to be met with:
but I think that I have conclusively shown the presence of
marine organisms throughout the raised beaches of Arctic Norway,
and consequently their marine origin.

2. Terrace-making in Kolguev Island.

On former occasions * I have pointed out the part which the ice-
foot performs in the formation of terraces in Polar regions. I observed

1 Alfred Newton, zz /itt. 1895.

2 Mr. EH. T. Newton, F.R.S., F.G.S., very kindly identified these specimens
brought from the raised beach at Vardo as belonging to Halicherus gryphus
(Grey Seal), Phoca hispida (Floe Rat), Gadus morrhua, with Buccinum undatum,
Modiola modiolus, and Pecten islandicus.

3 Ann. & Mag. Nat. Hist. ser. 4, vol. xx. (1877) p. 487; Nares, ‘ Voy. to
Polar Sea,’ 1878, vol. ii. pp. 341-342; Quart. Journ. Geol. Soc. vol. xxxiv.
(1878) p. 565.

a?
;

Vol. 52.] OF ARCTIC EUROPE AND ITS ISLANDs. 725

the making of a terrace lately on the island of Kolguev, not on a
great scale, but still sufficiently important to be a guide. The
broken ice-pack was pressed on to the western shore of Kolguev by
a strong gale for three days. ‘The width of this pack as I saw it
was from 3 to ? mile; it was a chaos of ice-material, blocks and
fragments pressed together by the force of the gale which was
raging outside, and huge waves dashing over the windward side
of the pack. Standing on the beach, the crushing and grinding of
the ice-blocks, with their dismal groaning, was audible above the
noise of the wind. An ‘angry’ pack under such circumstances
is a very awe-inspiring force of nature. As the ice pressed on the
shore, if drove before it banks of mud and gravel; these were pushed
up in ridges several feet high, and the tops of these banks were
rough and irregular. ‘The gale died away, and the ice, which had

Fig. 2.—Terraces across the mouth of the Gosina River, Kolguev Island.

[From a photograph by H. J. Pearson, 1895. |

acted as a breakwater, disappeared. Then came the influence of
the sea. No longer kept back from exerting its power on the
shore-line by the protective ice-barrier, the waves at the height of
the tide pushed their crests over the heaped-up ridges of mud and
gravel, and as they surged along levelled them as flat as a billiard-
table. As successive tides came in, not so high or strong as those
immediately following the gale, the raised surface was cut parallel
to the shore-line as straight and perpendicular as if done by a spade

726 COL. H. W. FEILDEN ON THE GLACIAL GEoLocy [ Nov. 1896,

for considerable lengths, 3 to 1 mile, according to the nature of the
shore,

Now, supposing what I saw happened, as it must often do, in the
autumn, at a time of great snow-precipitation, this newly-formed
terrace would be strongly protected, and when the sea washed against
it would rapidly be turned into ice, for snow absorbs sea-water with
marvellous rapidity, and the terrace would be enveloped in a mautle
as hard as glacier-ice. Supposing that this occurred accompanied
by emergence of the land, we have found here one cause for rapid
construction of terraces. That this does happen I have no doubt,
for where I saw the terrace made, namely, between the Gosina
and Kriva rivers, there were three other terraces standing behind this
last-formed one. The oldest of these was apparently above the
influence of present high tides, being about 100 yards inland, some
6 feet in depth, and possessing a perfect slope. For most of its
extent this terrace was covered by a protecting mantle of néve,
which was only bared at intervals; but in these places it showed
perfectly regular terrace-structure.

5. Glacial Geology of the Kola Peninsula.

As we sail eastward along the Murman coast of Russian Lapland,
we see on our right hand a bold and precipitous country. Its highest
summits appear to rise to 500 or 600 feet. The hills are planed down
to a general level, and no peaked mountain breaks the monotony
of the scene. In bays and indentations, immense raised beaches
are noticeable, especially to the westward of Cape Cherni. Sviatoi
Nos is the prominent headland which marks the entrance to the
White Sea when approaching from the westward. This promontory
forms the eastern side of Sviatonoskaia Bay, and the Ukanskoe
River enters its south-western angle. Here the river is about 4
mile wide and is navigable for vessels of small draught for 34 miles,
when the rapids commence and the tidal influence ceases. From
the entrance of the river to the rapids it is more correctly a fiord,
flanked on each side by steep heights of granitic, gneissoid, and
dioritic rock,! which rise to an elevation of 250 or 300 feet. A
remarkable feature in this fiord is a ridge of large boulders which
lines either shore to the height of 20 feet or more. It does not
seem credible that tidal influence could have ranged the boulders in
their present position, although the rise at spring-tides is 14 feet.

These boulders are of the same lithological character as the rocks
in the neighbourhood. On ascending to the uplands from the banks
of the Ukanskoe, an elevation of some 300 feet, we find a sombre
grey, monotonous expanse of ice-worn land with hardly any
surface-soil. There are hills, and eminences, and escarpments of
rock, with undulations and swellings in this rock-surface, but the
highest points are probably not more than 600 feet above sea-level,
and 500 feet, measured by aneroid, was the greatest elevation that

' See Appendix by Prof. Bonney, p. 742. -

Vol. 52.] OF ARCIIC HUROPE AND ITS ISLANDS, 727

Fig. 3.— View on the Ukanskoe River, Kola Peninsula, showing fringe
of erratics skirting the shore.

[From a photograph by H. J. Pearson, 1895. ]

the writer reached. A remarkable and prevailing feature of the
country is the vast number of erratic blocks spread over it in every
direction. Standing on some eminence we see around us countless
boulders, all clad in coats of shaggy lichen, reminding one of Catlin’s
pictures of herds of bison resting on the prairies of the Far West.
But ourastonishment is increased when we examine them individually,
and see the extraordinary positions that some of them occupy. Here
a huge block resting on a couple of others, there two or three raised
directly one upon another, again others standing as monoliths. From
the descriptions of the distribution of erratics in Finland and Lap-
land by Durocher, Wraxall, Clarke, and others, I was prepared to
see a remarkable number, but their dispersal over this portion of
the Kola Peninsula excited my astonishment.

When the eye becomes better acquainted with the position of these
blocks, certain salient features appear. Though they are spread
generally over the surface of the country and lie broadcast on
eminences and slopes, yet there is a tendency for them to collect in
hollows and undulations of the surface. A notable feature in these
aggregations is the entire absence of earth, clay, or sand between
the blocks. As all these boulders are covered with a thick lichen-
growth, it is impossible to note whether they are grooved or ice-

Fig. 4.—General view of the boulder-covered area on the tundra, in the
neighbourhood of Sviatot Nos, Kola Peninsula.

5 Lig. 5.— View of the boulder-covered area in the neighbourhood of the
Ukanskoe River, Kola Peninsula.

[From photographs by H. J. Pearson, 1895. j

Del, 52. GLACIAL GEOLOGY OF ARCTIC EUROPE, ETC. 729

scratched. Fragments which I took from some of them are pro-
nounced, by Prof. Bonney, to be fine-grained reddish granite,
moderately coarse, rather felspathic gneissoid granite, a pale red
gneissoid rock, granitoid or slightly gneissoid rock, and a dull red
very fine-grained felspathic sandstone. :

By referring to the valuable and exhaustive appendix of Prof.
Bonney (p. 742), it will be seen that these erratics agree so closely
in character with the rocks in situ of that part of the Kola Penin-
sula, that there can be little or no doubt as to their local derivation.
The accurate determination of these rocks by so high an authority
is of great importance. It presents strong evidence that there is no
importation of foreign rocks among the vast accumulations of boulders
on the Kola Peninsula—that no ice-sheet bearing its cargo of
rocks from the north ever passed through Barents Sea, or impinged
against the northern coast of Europe. It seems to me that in this
local manufacture of erratics on the Kola Peninsula we meet with a
striking example of the destructive powers of an ice-sheet resting
on a comparatively level area.

Considering the tendency of the erratics on this part of the Kola
Peninsula to accumulate in hollows and undulations of the surface,
it appears that we have evidence pointing to a somewhat sudden
recession or withdrawal of the ice-sheet. I do not accept a diluvial

Fig. 6.—Diaqgrammatic section of boulders in hollows, neighbourhood
of Sviatot Nos, Kola Peninsula.

Y Yyjm Lee 99 = Sm 97/ yy
Tet) /

theory, such as a deluge sweeping the erratics into the undulations,
but it seems probable that during the melting of the ice-sheet there
was a tendency for the decomposing ice to drift the blocks into the
hollows as we now see them. On the other hand, for all we know
to the contrary, it may be incidental to an ice-sheet’ moving over a
comparatively level land to push the boulders into depressions of
the rock-surface beneath it. Only in one spot did I meet with a
formation that had somewhat the appearance of a moraine, but as
it consisted entirely of blocks, without any sand or smaller débris
visible, it may be merely an accumulation of blocks formed under the
ice-sheet. This mound stood on the edge of a ridge, which looks
down towards the valley of the Ukanskoe River: its elevation is
415 feet, and it runs nearly due north and south, is about 2 mile in
length, and about 40 feet in height. in
Eastward of the estuary of the Petchora River the great
Bolshaia Zemelskija tundra stretches to the base of the Urals, and
along it we find proofs of elevation of the land in recent times.
The Arctic explorer, Mr. F. G. Jackson, in his book ‘The Great
Frozen Land’ (p. 128), tells us :—‘ We had been steadily travelling

SS

SS

730

Fig. 7.—Tundra, with boulders, neighbourhood of Ukanskoe River, Kola Peninsula.

e River

Ukansko

COL. H. W. FEILDEN ON THE GLACIAL GEOLOGY | Nov. 1896,

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across the frozen tundra for eighteen days,
when on the lst November we crossed
the Piatsoworyaha River, and on the fol-
lowing day, about 8 miles west of the
river, entered a most interesting region.
Right in front, and away to the north-
ward, there spread the amphitheatre of
an old bay, whose width would be about
15 miles, and its inmost reach at least
9 miles from the present seashore, Step
above step there ranged the old sea-
beaches, following the lines of the higher
land immediately behind them, and
girding with a terraced rampart the level
basin of salt marsh into which the waves
once rolled. The beaches themselves were
now thickly covered with grass, and the
grass with snow: but walking along the

terraces I found several pools of salt .

water, and a number of recumbent pine-
trees—one of which I measured, to find
it was 40 feet long, and 2 feet in diameter
at the thickest end.’ From this it would
appear that we are justified in assuming
that the secular elevation of what is now
the Bolshaia Zemelskija tundra was co-
incident with the emergence of the island
of Kolguev, with its marine boreal beds
now rising to a height of 250 feet above
the sea. Further, I think that the carto-
eraphers of maximum glaciation in Europe
should hesitate before extending an ice-
sheet over that wide region lying between
the Timan and Ural ranges, north of the
Arctic Circle.

In order to connect our survey of the
Arctic coast of Europe with the islands of
Novaya Zemlya, I will again quote from
Mr. F. G. Jackson, who, so far as I am
aware, 1s the only cducated person who
has traversed the island of Waigatz in its
entirety, and his observations are of
interest when taken in conjunction with
mine on Gooseland in Novaya Zemlya.
From Mr. Jackson we learn that there
are two main ridges on Waigatz, that on
the eastern side composed of limestone
and limestone-shale running in a north-
west to south-easterly direction, -and
having a general elevation of from 150 to

Q
.

Vol. 52.| OF ARCTIC EUROPE AND ITS ISLANDS. 731

300 feet, the other parallel to it on the western side of the island,
but not rising higher than 70 feet. The intervening portion and
the land bordering the sea he describes as tundra. Mr. Jackson
writes!:—‘ The tundra rolled away to the point, the ridges some-
times reaching a height of 30 feet above the intervening troughs.
Along the lowest level of the troughs shallow pools and lakes were
frequent .... Down in the troughs the soil was bluish mud ....
while on the ridges there outcropped the long friable sheets of lime-
stone-shale which I found all over the southern part of the island
and on the tundra around Habarova.... Round Dolga Bay (on
the north-western side of the island) there is every evidence of the
present shore-line being of comparatively recent existence. A raised
beach about 12 feet above present level runs persistently along
the cliffs.’

4, Novaya Zemlya.

My personal acquaintance with Novaya Zemlya is limited. I
have visited only a small portion of the western side of the south

‘island, between the parallels of 71° and 72° lat. N. The appear-

ance of this part of Novaya Zemlya is disappointing in scenic effects.
There is nothing in its character approaching the grandeur of the
western coast of Spitsbergen. Making for the shelter of Kostin Schar
or Strait, that protected reach of waters lying between Mesdu-
sharsky Island and Novaya Zemlya proper, we pass between low-
lying Gooseland and Mesdusharsky. Their topographical features
are quite distinct from those of the rest of Novaya Zemlya, and they
appear to be long low tracts of tundra just rising above the sea and
fringing the interior highlands.

In the vicinity of Rogatcheva Bay, where we made our first
landing, the country rises abruptly from the shore to the height
of between 500 and 800 feet, more or less. This hilly region,

- intersected by valleys with many lakes, extends for some 15 to

20 miles to the base of the interior range, which rises in a
series of sharply peaked and serrated mountains averaging some
2000 feet in height. At the time of our visit, in the latter part of
July, the land was generally clear of snow, little even remaining on
the central ridges except in their higher valleys and gorges. I
detected no glaciers on their flanks, and we saw no glaciers issuing
into Kostin Schar.

The rock-formations of this part of Novaya Zemlya dip at very
high angles, often nearly vertical, so that their outcrops appear as
ridges. On all sides these are shattered and riven by frost, so that
we walk over leagues upon leagues of splintered and shivered rocks.
This is the work of frost and subaerial disintegration. I can see
no evidence of the former extension of an ice-sheet over this area,
no ‘roches moutonnées,’ no glaciated surfaces, no rounded, mammil-
lated, ice-worn contours. Had these at any time existed one can
hardly suppose that they could have been totally removed by the

1 Op. cit. pp. 31, 32, 37.
Q.J.G.8. No. 208, 30D

732 GLACIAL GEOLOGY OF ARCTIC EUROPE, ETC. [ Noy. 1896.

action of frost. Iam making no reference to stratigraphical geology
in this paper, but it may be mentioned that some 5 miles inland
from Rogatcheva Bay I came across an outcrop of rock, apparently
very similar to a characteristic series of erratics in the glacio-marine
beds of Kolguev. It contains plant-remains, and is probably of
Jurassic age (see p. 744). It is quite within the range of reasonable
assumption that a portion of the Koiguev erratics may have been
floated from Novaya Zemlya.

It is to Gooseland and the islands in Kostin Schar that I wish
particularly to draw attention. The latter are worn down and
abraded in contour, but as the rocks of which they are composed
almost always crop out at a high angle, and as they are very shaly
in character and readily decay and splinter, no marks of glaciation
are left on them. From Prof. Bonney’s report they appear to be
sedimentary rocks of Paleozoic or Archean age.

All of these islands which I was enabled to visit have deposits of
boulder-clay lying in their undulations and hollows. I met with
sections showing a depth of 20 feet; the clay is of the same colour
as the rocks upon which it rests, and the included stones are angular
fragments of the same rock. I did not detect an erratic, or a
rounded stone, or an ice-scratched stone in any of this boulder-clay.
In many places it is full of shells of marine mollusca, Saaicava
arctica predominating, though I found other species common enough.
In some localities one might gather these shells by the bushel, few
of them broken, never triturated, and in some cases the two valves
are in contact.

This description holds good also of the part of Gooseland that
I visited, the abraded ridges, the deposits of boulder-clay in the
troughs, and the presence of shells of mollusca, all being character-
istic features. As I have expressed a very decided opinion that no
ice-sheet has ever extended over this part of Novaya Zemlya, I
may be asked to account for the presence of these widespread
deposits of boulder-clay, with the assemblage of the remains of
marine mollusca in them. I venture to urge the view that the
wearing down of Gooseland and the islands in Kostin Schar, and
the deposition of the boulder-clay, are entirely due to the action of
floating ice.

I pass on to give some examples which I witnessed of the force
that floating ice can exercise. Last summer I was observing a
narrow pack of floating ice which for a few days hemmed in the
western side of the island of Kolguev. ‘This ice-pack was moving
along the shore at the rate of 3 or 4 miles an hour. Some 7 mile
seaward from the beach on which I stood lay a shoal under water.
At this spot there was a constant turmoil and hubbub in the floating
ice. The unusually heavy pieces grounded on this shoal, and for
a short time checked the march-past of the ice-column. The delay,
however, was no long one; the pack accumulated behind, and by
its pressure forced the lagging blocks over the shoal. As a rule,
the accumulating pack dealt in a very summary way with the
obstructionists, by passing under them and turning them upside

Ps
ee ee ee eee eee CL —

N. Goose Cape

Fig. 8.—Sketch of Gooseland, July 4th, 1895.

if

esdusharsky Is.

Novaya Zemlya profile.
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S. Goose Cape Kostin Strait

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[We had run through 40 miles of pack-ice, but found it impenetrable and wedged fast on Gooseland for 10 miles, closing Kostin Strait,
and belting round Mesdusharsky Island. ]

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‘apbuays ypu pasanoa ‘Romasnno 10 ‘abprt pamunph v liq payoauuoa ‘umyay wysoy wi spunjst—'G *

Vol. 52.] GLACIAL GEOLOGY OF ARCTIC EUROPE, EXC, 735

down on the floe. The undersides of these blocks came up covered
with mud and detritus from their contact with the bottom, and
were swept onward by the ice-pack, their black colour being very
distinguishable on the white surface of the ice-stream. Now, to
force these blocks of ice, which were probably 8 to 10 feet in
thickness, over an obstacle must require immense pressure, and it
seems unreasonable to suppose that they do not exercise some
abrading force; if not, why should the blocks have their under
surfaces coated with material from the bottom? What I saw
occurring at Kolguev on a small scale has doubtless been carried on
extensively off the coast of Novaya Zemlya. Given a comparatively
flat tract under water, such as Gooseland was, and a constant
process of emergence, I see no reason why floating ice moving with
a hundredfold greater velocity than a glacier should not be able to
wear down ridges over which it passes, provided that the process of
‘secular elevation is bringing the land and the floating ice into
contact. The formation of boulder-clay, replete with mollusca,
- would be the natural sequence.

Next let us turn to a more distant part of the Polar area, where
the powers of floating ice are witnessed on a much grander scale. In
Smith Sound the fragments of the heavy floes of the Paleocrystic
Sea are summer and winter endéayouring to work their way south-
ward. Much of this ice is of stupendous thickness, floes 40, 50, and
even 100 feet thick being met with. This vast body of ice, ever
moving slowly southward through the strait, pushing over shallows,
and rubbing and grinding against the shore, must surely be gifted
with some wearing force. At headlands, or where the progress of
this pack is interfered with, the enormous power of floating ice is
exemplified. At such a point of pressure, the ice pushing against
the shore exerts extraordinary force. An enormous mass of floe is
brought to a stop against some part of the shore, while the check is
transmitted to the ice pushing behind. The edges of these various
floes are brought into contact with one another; they rise at
their edges and crumble upon themselves, forming ridges of pressed-
up hummocks 50 to 60 feet high. The pressure from behind forces
the grounded floe to act in a similar manner against the shore.
Slowly, as if urged by some hidden hydraulic force, the edge,
impinging against the shore, commences to rear itself up in a chaos
of ice-débris, and the blocks roll down on the floe or on to the shore.
The portion that has grounded or been jammed against the shore
being now pulverized, the obstruction is cleared, and the ice
resumes its onward march. Is it possible that such pressure
between land and floating ice can take place without some effects
being produced? I think not, for at such points of contact, when
we were able to reach them, we found the rock polished.

There are two or three islands lying along the eastern shore of
Grinnell Land in Smith Sound, which offer some useful testimony,
notably Norman Lockyer Island, which is encircled by several well-
defined terraces or sea-beaches to an altitude of 300 feet. These
terraces rest on rock-surfaces which show in places, where they are

736 COL, H. W. FEILDEN ON THE GLACIAL GEoLocy [ Nov. 1896,

laid bare, ice-worn surfaces and striations. Now, as the striz on the
limestone-rock of this island are as fresh-looking as if they had just
been made, I am at a loss to understand how this can be, if they are
due to the effects of land-ice. If so, how great the changes which
these striz must have encountered! First, what is now the water-
way of Smith Sound must have been occupied by land-ice, then it
must have disappeared, and the land must have sunk sufficiently at
least to allow of the highest terrace being formed, which would be a
submergence of 300 feet. Then followed a period of emergence,
during all which time the island has been undergoing contact. with
floating ice, and yet we are asked to believe that the scratchings of
the former ice-sheet have remained on the rock as fresh as they appear
on the specimen that I have now in my hand! It seems more
likely that the glaciation and striation went on simultaneously with
the emergence of the island from the sea, and that they are the
result of floating ice pushing over or along the island.

In Kostin Schar many of the islands and islets are connected
by ridges, and frequently one is able to walk from one island to
another over a causeway 4+ mile, more or less, in length. These
causeways are covered with rounded stones and shingle, the
pushed-up floe-ice lying on either side like the pictures of the
‘ passage through the Red Sea’ in the books of our childhood. If
we examine such a causeway we find that it has no character in
common with a moraine, for the shingle is rounded by the action of
the sea, and is only a few feet in thickness at the most, while in
spots where the shingle does not le the glaciated surface-rock
appears. Now, when we reach the end of a causeway and the base
of either of the connected islands, we not unfrequently find the floe-
ice pushing up the ridge and against the base of the island in a way
that shows it to have a scarping and destructive force. (See fig. 9,
p. 734.) We can point as evidence of this to the pieces of rock
and débris which have recently fallen from the escarpment of the
island on to the ice-floe, and to disjointed pieces of rock ready to
come away which are to be noticed at the meeting of the impinging
ice and the abruptly rising land-face. Moreover, as I have already
remarked, the surface of the ridge on which the edge or snout of
the floe-ice is pushed up is glaciated.

I have seen similar glaciated, shingle-strewed ridges appearing
above the sea, with the pack-ice grounded and pushed up on either
side, in many other parts of the Arctic regions—Spitsbergen, for
instance. I have in my possession a photograph of a well-marked
ridge in Loom Bay, Spitsbergen (taken during Mr. B. Leigh Smith’s
voyage to that country in 1873), which that distinguished Arctic
explorer gave meon his return. Being desirous of learning whether

the views of that highly qualified observer coincided with my own,

I recently communicated with him and received the following
reply :—‘ I believe that the ridge in Loom Bay, Spitsbergen, of which
you send me a sketch, was formed by the ice grounding on each side
of ashallow, and forcing up the shingle from the bottom. Thereisa
strong tide running into and outiof Loom Bay. In Hinlopen Straits

land

Vol. 52.] OF ARCTIC EUROPE AND ITS ISLANDS. 737

there are many low islands of columnar basalt which have been
polished by the ice driving over them. I do not recollect whether
the ends of these islands had been worn away or whether they
were connected by ridges.’

I have observed several minor phenomena connected with glacial
geology in Novaya Zemlya on which I should like to make some
remarks. There is a peculiar phase of rock-erosion which a photo-
graph shows better than any words can explain. The large lake

Fig. 10.— View on the Neckwatowa River, Novaya Zemlya, where it
assues from Wilczek Lake (showiny rock-erosion).

[From a photograph by H. J. Pearson, 1895.]

of Neckwatowa, which is on the western side of Novaya Zemlya
in lat. 71° 20' N., communicates with the sea by a passage that has
been cut through hard limestone-rocks thrown up almost vertically.
The fossils in these are so badly preserved that it is not possible to
indicate their precise age. (In connexion with this will be found
a report by Mr, E. T. Newton, F.R.S., in Prof. Bonney’s Appendix.)
This channel is about a mile in length, and from 80 to 100 yards
in width ; the walls on either side are precipitous, and their height
is 40 to 50 feet. There can be little doubt that the channel has
been cut out by the water and ice passing from Neckwatowa Lake
to the sea. (See fig. 10.) It will be noticed in the photograph that

738 COL, H. W. FEILDEN ON THE GLACIAL GEotocy [Nov. 1896,

on both sides of this channel at the present water-line the rock is
eaten away in the shape of a semi-culvert. This is largely due,
I imagine, to ice-abrasion ; but at the same time does it not point
to a lull in the upward movement of the earth in this part of
Novaya Zemlya ?

A phenomenon observable in all Arctic regions, whence the snow
dissolves in summer, has not, I think, received adequate explana-
tion. It is that tendency of the surface-stones to arrange them-
selves most commonly in the form of hexagons. We see this ona
small scale on Scottish mountains, and very commonly in Iceland.
Paijkull refers to its occurrence in Iceland, and gives a sketch*
illustrating this disposition of the stones on an Icelandic ‘ Melr,’
His explanation is not altogether satisfactory, though it is founded
upon that of so high an authority as Prof. Steenstrup, namely,
that the earth rendered soft by the melting of the snow in spring
has become dried by the heat of summer; that rifts or cracks are
formed in it, and when a storm occurs the small stones that Jie on
the surface of the ‘ Melr’ are swept down into them. This expla-
nation does not, however, account for their formation on the large
scale met with in high Arctic latitudes. I have seen in Novaya
Zemlya these arrangements of stones occurring in groups, the dia-
meter across each enclosure being 18 inches to 2 feet—the stones
composing the enclosures being of considerable size, a foot or more
square; the interior was occupied by a mound resembling a mole-hill.
I think that the arrangement is unquestionably connected with the
melting of the snow, but why the stones should be distributed as
they are is not quite clear.

To another phenomenon that we observed on Gooseland we
gave the name of ‘stone-bogs.’ Tracts of soft mud, in which a
man sinks over the boot when walking, were frequently covered
thickly with stones, so much so that we could walk in comfort over
these treacherous spots for a hundred yards at a stretch. The
stones moved under the tread, but did not sink. They lay on the
surface of the quaking mud as smoothly as if a roller had been
passed over them.

5. Franz Josef Land.

We have evidence that secular elevation of the land is as recog-
nizable a feature in Franz Josef Land as in other parts of the Polar
area. Payer frequently mentions the raised beaches, visible on all
sides, during his sledge journey up Austria Sound,’ while the
members of the Jackson-Harmsworth Expedition report that their
winter house ‘is situated on a raised beach 115 feet above the
sea.’ ®

1 «A Summer in Iceland,’ p. 21, Eng. trans., London, 1868.
2 ‘New Lands within the Arctic Circle.’ —
3 Montefiore, Geogr. Journ. vol. vi. (1895) p. 507.

Vol. 52.] OF ARCTIC EUROPE AND ITS ISLANDS.

6. Spitsbergen.

Spitsbergen, especially its western
coast, presents the most sublime and
magnificent scenery that 1 have met
with in Polar lands. Its western shore
is as easy of approach in summer as
that of Norway, and secure anchorages
and harbours can always be reached.
It is a land pre-eminently suitable for
the study of glacial effects, for not only
do we find there the forces of land-ice,
but also, as it isan area of rapid emer-
gence, the phenomena connected with
glacio-marine action can be seen in
progress. Along the shores of the great
estuaries, such as Ice Fiord, old sea-
beaches and terraces, containing the
shells of recent mollusca in great
quantities, are frequent. But the only
novel observation which I have to record
is that, owing to the rapid elevation of
the land, we can examine in detail
immense deposits originally formed
under water in front of glaciers.
These deposits in many cases now lie
between the present shore-line and the
edge of the glacier of to-day, and their
thickness and extent make them de-
serving of attention. A very notable
formation of this nature is to be found
at the head of Green Harbour, one of
the minor indentations on the southern
side of Ice Fiord. ‘The front of the
glacier that now occupies the valley is
about a mile distant from the present
shore-line. Fronting this glacier, the
terminal face of which is about 50 feet
in height, and extending entirely across
it for 14 mile in length, is a range of
low hills, some 50 to 70 feet high
and 4 mile in width. These hills have
undergone much subaerial erosion, and
channels have been cut in them by the
numerous streams issuing from under
the glacier. Following up one of these
watercourses, which average from 25
to 50 yards across, with a very level
bottom, we find sections of mud and
clay, rising like walls on either side to

‘pyoounds) DWT JO S{TEYS pux souojs
HM “GYySIoy UT 309} OL 0} OG ‘STTHY AvP pur puny

739

‘uahuagspdy ‘unogunyy waaty fo poay oy2 yn ‘sypry-pnw pun ‘ournsow ‘warampb fo uoroas oyjmmunuboyg— 1 ‘SLT

740 GLACIAL GEOLOGY OF ARCTIC EUROPE, ETC. [Nov. 1896,

a height of from 50 to 60 feet. These beds contain numerous
stones, but neither they nor the stones themselves show any sign of
stratification ; in them I found shells of Mya truncata, but in no
great quantity. That these beds are of submarine formation is con-
firmed by the existence of raised beaches in the neighbouring fiords,
and along the adjacent line of coast, at a higher elevation than the
beds which I am describing. Between the present face of the
glacier and the perpendicular wall of the mud-hills runs a sort of
ditch, dry moat, or open space some 30 yards in width, along the
entire front of the glacier. The bottom of this ditch or moat is
thickly strewed with morainic débris composed of rounded ice-worn
stones, many being deeply grooved, scarred, and scratched. Through
this slope of rocks and stones the glacier-streams were pouring forth
when I visited the spot in July 1894.

If the glacier, as it now does, can force this immense quantity
of rounded and scratched stones from beneath it, the same process
must have been going on when its snout was submerged in the sea.
It seems to me that when emergence of the land is proceeding, as
it is now in Spitsbergen, there must come a period when the
water at the face of the glacier shoals sufficiently to allow of the
bay-ice which forms throughout the winter freezing deep enough
to incorporate the boulders of the moraine. This being so, quan-
tities of ice-scratched and ice-polished boulders, stones, and pebbles
must be floated away on the breaking up of the bay-ice in summer.
This would be a simple explanation of the occurrence of the vast
number of scratched erratics which are to be found in the glacio-
marine beds of Kolguev Island.

It is well known, and has frequently been remarked by tra-
vellers in Greenland, that in the neighbourhood of many of the
glaciers discharging into the sea the water is discoloured with
sediment, and contains a large quantity of suspended material.
That this matter must in time be precipitated is evident; and when
lifting the ship’s anchor from the front of some of these glaciers
(notably the ‘'yndall Glacier in Bardin Bay on the north-western
side of Greenland) I have seen it come up with many pounds’
weight of unctuous mud intermixed with sea-shells adhering to the
flukes. It is therefore quite evident that water issuing from
under a glacier in the Polar regions, and discharging from under
the ice into the sea, can lay down glacio-marine beds in the ocean,
and that the occurrence of ice-scratched stones throughout these
beds can be accounted for.

My object has been to set forth in this paper the effects of
glacio-marine action in the alteration of coast-lines, the deposi-
tion of boulder-clays, and the glaciation and polishing of rocks by
floating ice. I have not alluded to the glacio-terrene geology of
the Far North, as it would have extended this paper to unreasonable
limits. I have endeavoured to avoid theories and hypotheses, and
have confined myself to a bare narration of facts as I have observed
them andas I understand them. Do not suppose that for an instant

Vol. 52.] SPECIMENS COLLECTED IN ARCTIC NORWAY, ETC. 741

I compare the glacial effects of a continental ice-sheet as we find it
now in Greenland, or as it formerly existed over a large portion of
Europe and North Americus, with glacio-marine action; but un-
doubtedly the latter has been and still is a not unimportant factor
in glacial geology.

In conclusion, I beg to thank Prof. Bonney for his kindness in
adding two valuable appendices to this and my former paper. His
examination and description of these rocks, some of them from
remote and inaccessible localities, are valuable in themselves; but
I am most grateful for the light which they throw on the origin
of some of the erratics that I have met with.

There can be no doubt that many of the erratics found in the
glacio-marine beds of Kolguev are of precisely the same lithological
character as rocks found in place in Novaya Zemlya, and we may
presume with great confidence that they were carried thence by
floating ice and dropped to the bottom in that part of Barents Sea
which has now risen into dry land. Again, it is extremely inter-
esting to find, from Prof. Bonney’s investigation, that the vast
accumulations of boulders on the Kola Peninsula are derived from
local rocks, without, so far as we know, any foreign admixture.

APPENDIX.

Report on SPECIMENS CoLttEcTED by Col. H. W. Freinpen in Arcric
Wouwar, cic. By Prot. T. G. Bonnuy, D.Sc¢., LL.D., F.R.S.,
V2.G.S.

In the following notes the specimens collected by Col. Feilden
are grouped according to localities and arranged in the order of the
dates on the labels.’

(i) From Rock 1y prace, Stor Tams6, Porsancer Fiorp, Norway.

(28.) A fine-grained, faintly speckled, light grey rock, apparently
either a quartzose gneiss or quartz-schist, without strongly marked
foliation. On examining a slice, quartz proves to be the dominant
mineral. It occurs in rather elongated irregularly-outlined grains,
with borders of a different tint (with crossed nicols). A dark
olive-brown biotite is present in both fair-sized flakes and tiny
flakelets, with some felspar, but much less than one would expect
from the macroscopic aspect of the rock; there are also a few
small garnets, a little iron-oxide, and zircon. Macroscopically and
microscopically the rock reminds me of some quartz-schists which
I have collected near Braemar, Aberdeenshire, and in the neighbour-
hood of Clifden, Connemara.

' The numbers are those affixed to the specimens by Col. Feilden. Sections
were prepared for the microscope in cases where the rock seemed likely to be
specially interesting. In other cases a fragment was powdered, and the
material was mounted on a slide and examined.

742 PROF. 1. G. BONNEY ON SPECIMENS cotLécrED By [Nov. 1896,

(11) BovLDERS FROM TUNDRA IN THE NEIGHBOURHOOD OF
Svrator Nos, Kota PeninsvLa.

(29.) A fine-grained reddish granite, rather rich in felspar and
poor in mica (biotite and a little muscovite). Examination of the
powder shows that some of the felspar is ferrite-stained, that micro-
cline is present, and that the iron oxide probably is hematite.

(19, at Sviatoi Nos.) A moderately coarse, rather felspathic,
reddish-coloured gneissoid granite; the biotite (not very abundant)
exhibits a slightly linear arrangement. <A good deal of muscovite
is seen on close examination with a lens; this also is found in the
powder, together with biotite and a very light brown mica, as well
as plagioclastic felspar and microcline. The outer surface of the
fragment has assumed in weathering a peculiar, rather lumpy,
slightly glazed aspect. Possibly it may be part of a vein.

(8.) A dullish red (slightly mottled) very fine-grained felspathic
sandstone, with a few specks of mica, bearing some resemblance to
Torriden Sandstone, but with smaller grains than is usual in that
rock. Examination of the powder shows the quartz-fragments to
be angular in form and somewhat ferrite-stained, with plagioclase
and microcline among the felspar, also a tiny chip of garnet.

(24,) A whole stone, labelled ‘ miniature boulder,’ about 3” x
1-75" x 2:25", rudely oblong, slightly tapering at one end. This
appears to be a granitoid or slightly gneissoid rock.

(26.) An ovoid pebble, rather blunted at one end, of moderately
coarse, pale-red gneissoid rock.

(16.) A fine-grained dioritic rock with a very slight approach
to a foliated structure—felspar light-coloured, hornblende dark.
Examination of a slice shows the following minerals :—(a) Green
hornblende, strongly dichroic, with occasional inclusions (see 22,
p. 748) in irregularly-shaped grains ; (>) biotite in fairly idiomorphic
flakes, often in close association with the hornblende, as if formed
at its expense ; (¢) felspar—in quantity about one-half of the rock
—in irregularly-shaped grains, being often moulded on the mica;
occasionally slightly decomposed, much of it plagioclase, with both
albite- and pericline-types of twinning. Sometimes a grain, which
with ordinary light appears single, is found on applying the nicols
to be composite. A few grains of quartz, granules of iron oxide,
and several microliths of apatite also occur. The structure is
peculiar: it may be the result of dynamic action, but there is
nothing to prove this; possibly it is due to a partial fusion anterior
to final consolidation, by which biotite has been produced at the
expense of original hornblendic and of felspathic constituents.

(ii1) Rocks rn piace, Fiorp or Uxansxoz River,
Kora PEninsv.a.

(20—At edge of water close to camp, June 24th.) A rather coarse
eneissoid rock, with some approach to a banded order in its con-
stituents—like Archzan specimens from Greenland and Norway.

Vol. 52.) Col. H. W. FEILDEN IN ARCTIC NORWAY, ETC. 743

Quartz, felspar, and biotite are readily seen, The powder shows
the felspar (orthoclase probably predominating) to be rather full
of minute enclosures; also very dark-coloured biotite, with some
white mica, a little garnet, and (?) epidote.

(12—June 26th.) A rather coarsely crystalline, reddish granitoid
rock, with much felspar. A slice shows the following minerals :—
(a) quartz, in grains of moderate size and irregular outline, gene-
rally composite ; in it hair-like microliths and small fluid cavities
with bubbles are rather frequent. (6) Felspar in grains variable in
size and interrupted by inclusions. Microcline is common, but the
other grains, as a rule, show no signs of twinning. Occasionally
they are rather decomposed, and contain many flakelets of colourless
mica irregularly disposed. Also in parts towards the outside they
scem to break up into a mosaic of granular felspar, with an occa-
sional trace of micropegmatitic structure. The inclusions men-
tioned above are sometimes quartz, sometimes felspar, the latter
seemingly a different variety. (c) A ferro-magnesian mineral, irre-
gular in outline, inclined to be opaque, which in most, if not in all
cases, is biotite. A small quantity of a light-coloured mica, which
not improbably is a bleached biotite, also occurs. (d) In one
part of the slice two or three small patches of a more decomposed
mineral, intercrystallized with the felspar, suggest the possibility that
a little eleeolite may be present. There is a little apatite and hama-
tite, and a grain or two of a colourless mineral, possibly andalusite.
The mosaic structure in the quartz and the felspar is not improbably
the result of some secondary change, perhaps due to pressure, but
not to actual crushing. From the general appearance of this rock
I should infer that it is of Archean age.

(21.) A moderately coarse, rather felspathic granite. The powder
shows quartz, felspar (orthoclase, microcline, and a little plagio-
clase), two kinds of mica, one being a dark biotite, the other (in
small amount) having a very light-brown colour.

(22.) A fine-grained dioritic rock—felspar nearly white, horn-
blende (abundant) nearly black. Examination of a slice shows that
rather more than half the rock consists of a rich green hornblende,
which is strongly pleochroic, irregular in outline, including occa-
sionally grains of water-clear felspar, iron oxide, and (?) sphene.
Small cylindrical or plate-like inclusions of a dark brown colour
also are frequent, like those common in diallage, hypersthene, etc.,
arranged parallel with the planes of o P. The intervals between
the hornblende are occupied by small, rather irregularly-shaped
grains of felspar, often water-clear (possibly in some cases quartz),
together with a nearly colourless epidote. Both the hand-specimen
and the slice exhibit a slight approach to foliation. A considerable
amount of secondary mineral arrangement is suggested by the
structure of the rock, but there is no definite evidence that this has
been the direct result of pressure,

744 PROF. T. G. BONNEY ON SPECIMENS COLLECTED BY [ Nov. 1896,

(iv) Novaya ZEMiya.

(18—-Vicinity of Rogatcheva Bay, July 17th, 1895.) A very fine-
grained, rather felspathic sandstone, of an olive-grey colour, some-
what carbonaceous and containing plant-remains, very like those
specimens from Kolguev Island described in a former paper (anted,
p. 61). The powder shows quartz, angular chips of felspar (no
evidence as to species), two or three flakes of mica (white and
brown), and a grain of tourmaline,

Mr. A. C. Seward, M.A., F.G.S., who examined similar rock-
specimens from Koiguev Island, has kindly furnished a note on this
one. He states that ‘the broader fragment (of a plant) may bea
fern-rachis, but any trustworthy determination is impossible. The
smaller needle-like fragments suggest either Pinus-leaves or, per-
haps more probably, leaves of Czekanowskiana, a fairly common
Jurassic genus. Heer and others have described various species of
the latter from Arctic plant-beds. The appearance of the rock and
the fossils reminds me somewhat of specimens from Spitsbergen and
Greenland which I recently saw in the Stockholm Museum, but my
recollection of them is much too imperfect to be cited as evidence.
On the whole, however, a Jurassic age seems to me the most
probable.’ r

(9—Basement-rock, Kostin Schar, July 17th.) A rather hard, very
fine-grained sandstone, exhibiting well-marked current-bedding.
The powder shows quartz, felspar, two kinds of mica, one grain
which is probably tourmaline, and two zircons, slightly smoke-
coloured. .

(7—Kostin Schar, July 17th.) A dark greenish-coloured rock, the
surfaces of which, though weather-stained, in places suggest a
clastic structure. Examination of a slice shows the rock to consist
of fragments, the interspaces being filled up by a carbonate (often
calcite, possibly sometimes dolomitic). This is occasionally spotted
with small flecks which polarize with varying intensity, and pro-
bably represent dust from the larger fragments. ‘These fragments
are both rocks and separate minerals. Of the former the majority
result from the hydration of a basic glass, and the material may be
now designated ‘palagonite.’ One of them exhibits a series of parallel
wary lines, like a fluxion-structure, sometimes (but not always)
parallel with the exterior. The bands are composed of a minute
green fibrous or platy mineral, the orientation of which is not
always uniform. Its pleochroism is weak, its double refraction is
feeble, and its extinction is oblique, but at a rather small angle;
the mineral may be clinochlore. it also occupies what appear to
have been small cavities in the rock. Embedded in the mass are
small crystalline grains, often clustered, of a very pale brownish-
buff mineral, with a rather granular surface, fairly high refrac-
tion, but not rich polarization-tints; their general aspect suggests
a ferrous carbonate. One small fragment (with a few cavities) is
full of minute lath-like felspars (the extinction-angle agreeing best
with that of oligoclase), and resembles an andesite; another one is

Vol. 52.] col, H. W. FEILDEN IN ARCTIC NORWAY, ETC. 745

generally similar in structure, but the crystallites are even less
distinct. Several ‘earthy’ scoriaceous fragments occur; others,
which are minutely granular in structure and of a brown or dark
colour, may represent a sedimentary rock (varieties of indurated
gritty mud). Among the mineral fragments are chips of quartz,
often angular, retaining sometimes traces of a crystal-face, but
occasionally augmented by secondary deposit. Hematite is present,
also (rather numerous) minute crystals of a brownish tint, with
high refraction and rich polarization-colours, probably zircon. The
vesicles in the fragments are filled either by the carbonate already
mentioned, or (much more rarely) by a zeolite, which bears some
resemblance to heulandite. It is impossible to say whether this
interesting rock is a volcanic ash, or is mainly composed of volcanic
material transported from no great distance; but I incline to the
latter view. From its general aspect I should conjecture its age to
be either early Paleozoic or very late Archean.

(2, 3, 4—Island in Kostin Schar, July 19th.) Dull grey, fine-
grained, sedimentary rocks, consisting, probably, of quartz and more
or less decomposed felspar, with a few flakelets of white mica.
They are rather fissile, and in (2) the structure has the appearance
of a true but imperfect cleavage. This specimen contains a few
specks of pyrite.

(v) Neckwarowa Lake anp River, tat. 71° 20' N.

These rocks are fossiliferous limestones, and they were accordingly
submitted to Mr. E. T. Newton, F.R.S., who kindly examined
those from Kolguev Island, and has favoured us with the remarks
quoted below.

5,17,27 are from Maltzan Island in Neckwatowa Lake (July 20th).
‘They seem to be portions of the same rock. Upon their
weathered surfaces are rod-like bodies, 1 to 2 millimetres in
diameter, the longest of which measures perhaps 15 millim. ‘This
rock is so crystalline that microscopic sections fail to reveal any
definite structure in these rods, although some exhibit indistinct
radiating lines and others rather resemble Amphipora.’

The other specimens, seven in number, are from the banks of the
Neckwatowa River (July 22nd). ‘(10, 11, 14) contain portions of
corals which, on account of their short septa, are thought to be
Amplexus or some allied form. (25) includes a portion of a tur-
binate coral, a Rhynchonella, possibly an Athyris or Spirifera, and
what looks like a fragment of a crinoid stem, having four divisions
in the central aperture. (This specimen and No. 11 are labelled
Iron Gate.) (6) shows indications of a coral, and perhaps also
of a brachiopod ; (31) contains remains of a coral ; (13) includes a
fragment of a stromatoporoid, possibly Jdiostroma or Amphipora.’

746 COL. H. W. FEILDEN ON THE GLACIAL GEoLogy [ Novy. 1896,

(vi) Rock or Loom Istanp rn Kostin Scar.

(23—July 23rd.) The specimen bears a general resemblance to
Nos. 2,3 & 4, but it is a little more compact and darker coloured.
It exhibits a slight fissility, but whether this be a true cleavage is
doubtful. Some very faint markings on the surface may possibly
be traces of an organism (? vegetable).

(vii) Sour Goosrzanp, Novaya ZEMLYA, VICINITY OF
Betootoua Bay.

(1—July 24th.) A darkish, rather more carbonaceous rock than
the last one, rudely fissile, as one may judge from the form of the
specimen, which evidently was a loose flake.

(15—same date.) Another natural flake of a rock generally similar
to the last, but darker in colour and rather more fine-grained.

(30—same date.) A similar rock, but still darker and more fine-
erained.

These rocks (including 23) are not unlike some of the flaky or
imperfectly slaty Palzeozoic mudstones.

The collection indicates the presence of Archean, Paleozoic
(later and possibly earlier), and some Mesozoic rocks in the region
visited by Col. Feilden. The sandstone with plant-remains appears
to be identical with that from erratics in Kolguev Island. The
fossiliferous Paleeozoic limestone (though unfortunately its organisms
are in worse preservation) bears a general resemblance to some of
the specimens from that island, and the same may be said of certain
of the crystalline rocks of Archean aspect. ‘Thus the Kolguev
erratics may have come from Novaya Zemlya, including the ad-
jacent islands.

DIscussIon.

The Presrprenr congratulated the Author on the very interesting
facts which he had brought before the Society. His observations
made on the spot were a warning to those of us in the South who were
inclined to theorize about an universal ice-sheet. ‘The Author’s
observations seemed to agree in a remarkable manner with those
made by the Canadian geologists, and he would call upon Sir W.
Dawson for an expression of his views and of those formed by the
Canadian Surveyors.

Sir Writt1m Dawson remarked that, as a Canadian, he had
listened with especial pleasure to the interesting paper of Col. Feilden,
since the raised beaches with marine shells which had been described
were very similar to those on the Lower St. Lawrence, as were
also the fossiliferous boulder-clays and their contained stones with
bases of acorn-shells and patches of polyzoa. The effects of floating
ice as described by Col. Feilden were also similar to those observed
in the estuary of the St. Lawrence and on the coasts of Labrador and

~

Vol. 52.] OF ARCTIC EUROPE AND ITS ISLANDS. (47

Newfoundland. The whole of the facts were tending to the con-
clusion, that instead of ascribing the phenomena of the Glacial Age
to continental ice-sheets, we should have to be content with local
glaciers on the higher lands and cold ocean-currents pervading the
submerged lower levels. Evidently the phenomena could not be
explained without giving attention to the evidence of continental
submergence, afforded by the clays containing marine remains and
the ancient shore-lines found at very high elevations. The action
of shore- and field-ice during periods of gradual subsidence and
elevation could alone account for the great beds of boulder-clay
holding marine shells and tests of modern foraminifera, and the
term ‘ unstratified till* was not always appropriate, as where long-
continuous sections could be observed, successive beds were often
marked by colour-lines, by rows of stones or boulders, or by fossili-
ferous layers.

Mr. Marr congratulated the Society on having heard this ex-
cellent paper. He was particularly interested to learn that deposits
whose marine origin was so ably advocated by the Author displayed
no signs of stratification.

The Avrnor replied, thanking the Fellows for the reception
accorded to his paper.

Q.J.G.8. No. 208. 35

748 | MR. F. W. HARMER ON THE [Nov. 1896,

41. On the Putocenr Deposits of Hottann and their Revation to the
Enerish and Beteran Craes, with a Svueeestron for the
EstaBLisHMeEnt of a New Zons, ‘ AMSTELIEN,’ and some REMARKS
on the GnograpuicaL Conpitions of the Priocenn Epocu 7
NortHern Evropz. By F. W. Harmer, Esq., F.G.S. (Read
May 27th, 1896.)

[Puates XXXIV. & XXXV.—Mapvs. |

I. InrRopvuction.

Wuite engaged in the study of the conditions under which the
English Crag-beds were deposited, I was fortunate enough to receive
from Dr. J. Lorié, of Utrecht, two important papers on the strata
met with in some deep borings in different parts of Holland.’ ‘These
borings reveal the remarkable fact that the Newer Pliocene beds
which underlie that country not only attain the great thickness of
nearly 500 feet, but have been depressed at one point more than
1000 feet below their original position. The enquiry suggested
itself whether this subsidence was connected with the series of earth-
movements by which the Older Pliocene deposits of the South of
England, of the North-east of France, and of Belgium have been
raised to a height of between 500 and 600 feet above the level of
the sea, how far the influence of these disturbances could be traced
in Kast Anglia, and in what manner the deposition of the Crag-
deposits was affected by them.

The facts I have now to submit show that these movements of
upheaval and subsidence have this in common, that they were not
confined to one period, but went on, though not continuously, from
the Pliocene until late in the Pleistocene epoch. The central
portion of the area has not been affected by them to any large
extent, and seems to have formed the pivot of the disturbance,
while depression has increased progressively in a northerly direction,
and elevation has been greatest in the south. For the most part,
each of these movements has operated in the direction which it first
assumed, with a decided interruption, however, at the end of the
Pliocene period, and it will be seen by the section (fig. 4, p. 761)
that the total rise of the bed of the Pliocene sea, on the one hand,
corresponds, though not exactly, with the greatest depth to which it
has sunk on the other. The maximum disturbance, so far as the
evidence goes, seems to have been along a line running 8.W., and
N.E. from the Straits of Dover to the coast of Holland. The Hast
Anglian area has been affected, though not to so great an extent,
and I think it will be seen that these movements have had an
important influence on the deposition and distribution of the English
-Crag-beds.

1 «Contributions 4 la Géologie des Pays-Bas, No. 1, extr. des Archives
du Musée Teyler, ser. ii. vol. ii. (1885) Haarlem ; do. No. 4, Bull. Soc. Belge
Géol. vol. iii. (1889).

Wol..s52:| PLIOCENE DEPOSITS OF HOLLAND. 749

The attention of English geologists was drawn to Dr. Lorié’s
researches by Mr. C. Reid, in 1886,' and that gentleman has since
dealt with the subject incidentally in his admirable work on the
‘Pliocene Deposits of Britain’;* but I do not think that these
discoveries, the most important that have been made for many
years in Pliocene geology, have received the attention which they
deserve, and I offer no apology for further alluding to them at some
length, especially as I believe that they furnish a clue to guide us
in working out some of our own problems. My apologies are
indeed due to Dr. Lorié (whose courtesy in placing all his material
at my disposal I gladly acknowledge), in that I have ventured to
differ from some of the conclusions which he has reached.

The consideration of this subject led me to review the work in
which, for nearly twenty years, I was engaged in co-operation with
my lamented friend the late 8. V. Wood, Jun. This work was
wholly interrupted by his death in 1884, and until a few months
ago no opportunity presented itself to me for resuming it. I desire
in this paper, in the first place, to point out a few cases in which
I am now disposed to modify the opinions which we formerly ex-
pressed, and wherein I still differ from the views of other geologists.
I shall, secondly, endeavour to show that a great part of the beds
met with in the subsoil of Holland are considerably newer than the
Scaldisien of Belgium, to which they are usually referred ; and lastly,
by grouping together the different facts which bear on the question,
I shall attempt to sketch out a rough but continuous outline of the
history of the Anglo-Dutch basin during the newer Pliocene period.
For this purpose it will be necessary to refer from time to time to
the work of other observers, but I will do so as briefly as possible.

II. CorRELATION OF THE ENGLISH AND THE DutcH AND
Beteran CraGs.

In the opinion of Sir Joseph Prestwich, the sea of the Coralline
Crag may have attained a depth of from 500 to 1000 feet,* but
Mr. Wood and I always thought this estimate excessive. From
considerations which I hope hereafter to lay before this Society, it
appears to me that our suggestion of from 250 to 300 feet may still
have been somewhat too high. However this may be, it is clear
that an elevation of the Suffolk area took place after the accumula-
tion of the Coralline Crag, since the upper beds of the Red Crag,
deposited in shallow water, are bedded against it, and sometimes at a
lower level. The upheaval of the Pliocene sea-bottom has been much
greater in the South of England. At Lenham, in Kent, fossili-
ferous beds, approximately of the age of the Coralline Crag, occupy

1 *Nature,’ vol. xxxiy. p. 341. Mr. Reid points out in this article the connexion
between the elevation of the Weald and the depression which has affected the
Diestien beds found in the Utrecht boring. As to the upheaval of the southern
and the subsidence of the northern part of the English Crag area, see 8. V.
Wood, Jun., Quart. Journ. Geol. Soc. vol, xxxvi. (1880) p. 458.

2 Mem. Geol. Surv. 1890.

3 Quart. Journ. Geol. Soc. vol. xxvii. (1871) p. 135.

3E2

750 THE PLIOCENE DEPOSITS OF HOLLAND. [Nov. 1896.

a level, according to Mr. Reid, of about 600 feet above the sea.”
This elevation, thus increasing to the south or south-west, was —
accompanied by a subsidence of the northern, or rather of the north-
eastern, portion of the East Anglian area. Sir Joseph Prestwich
found the base of the Crag at Sutton, where it rests on the London
Clay, to be at one place 8 feet, and at another 20 feet above the high-
water mark of the estuary of the River Deben.?, Mr. Whitaker
has given the results obtained in three borings near Orford, about
8 miles to the N.E. of Sutton, in two of which it was reached at
26 feet below Ordnance-datum, and in the third at a less depth.’
At Aldeburgh, 5 miles farther to the N.E., I bored last autumn into
the Crag 20 feet below the water-line, without reaching the London
Clay, and I was informed that former borings had been carried
down 30 feet with a similar want of success. Farther north, at
Saxmundham, the junction of the Crag with the Kocene beds is
said by Mr. W. H. Dalton to occur at a depth of 60 feet,’ and at
Southwold, 11 miles N.E. of Saxmundham, at about 140 feet below
the sea-level.® (See section, fig. 1, p. 751).

It has been stated that in a boring in the harbour at Lowestoft
the Chalk was met with, 80 feet below high-water mark. If this
be correct, there exists under that town a submarine ridge rising
through both the Eocene and the Pliocene beds,’ but at Yarmouth,
40 miles N.N.E. of Sutton, the bottom of the Pliocene basin occupies
nearly its normal position, the surface of the London Clay being
there found at a depth of 150 feet below the sea-level.°

If the Crag beds are present under Yarmouth, as seems not im-
probable, there is a difference in the level of the base of these
deposits of 180 feet in about 40 miles. The section (fig. 1) will
show that, although the surface of the Chalk along this line is ex-
ceedingly irregular, the base of the Crag dips northward in a fairly
uniform manner.

The section (fig. 2, p. 753) from Norwich to Yarmouth shows
that the Pliocene beds dip similarly from W. to E. Near the
Cavalry Barracks at Norwich, the Crag sands rest on the Chalk
at about 45 feet above the River Wensum. At Bramerton, 4 miles
to the E.S.E., they are but little above the water-level, while beyond
that place they dip below it. The line of junction of the Chalk

1 Op. cit. p. 45. 2 Op. cit..p. WG,

3 Dalton & Whitaker, Mem. Geol. Sury. Aldeburgh, 1886, p. 53.

4 Sir Joseph Prestwich (Quart. Journ. Geol. Soe. vol. xxvii. 1871, p. 496,
pl. xx.) shows in one of his sections the junction of the Coralline Crag and the
London Clay at Aldeburgh as considerably above O.D., but this is inaccurate.

5 Dalton & Whitaker, Mem. Geol. Surv. Aldeburgh, 1886, p. 53. Mr,
Whitaker gives, on hearsay evidence (p. 52), a depth of 130 feet below
Ordnance-datum for the base of the Crag at Leiston, but is this correct ?

6 Whitaker, Mem. Geol. Surv. Southwold, 1887, p. 78.

7 Mem. Geol. Surv. Southwold, 1887, p. 4. The Lowestoft boring is cited
by Mr. Whitaker on the authority of Mr. A. A. Langley. The presence of the
Chalk so near the surface at that place appears improbable. May it not have
been the Chalky Boulder Clay that was met with? Itis known that this deposit
occurs in the Waveney Valley at a considerable depth below the alluvium. In
the section (fig. 1) I have shown the Chalk at Lowestoft with a query.

8 Quart. Journ. Geol. Soc. vol. xvi. (1860) p. 450.

Fig. 1.—Section from Sutton to Yarmouth,

SUTTON ORFORD SAXMUNDHAM SOUTHWOLD LOWESTOFT YARMOUTH
!

: |
'

| |
! : H
! i 1
' 1 |

1 !
1 1 !

? CRAG

EOCENE

3800

400.

500) feet below Ordnance-datum.

oo THE PLIOCENE DEPOSITS OF HOLLAND. [Nov. 1896.

and the Crag from Norwich to Bramerton, produced eastward in the
direction of Yarmouth, very nearly intersects the base-line of the
Pliocene beds under that town. ,

When we pass to the other side of the North Sea and of the
English Channel, we find evidence of similar earth-movements, but
on a larger scale. While an elevation of the southern portion of
the Pliocene area, corresponding to that at Lenham, has taken place
in Belgium and in the North-east of France, the northerly
depression has in Holland reached a total depth, possibly, of more
than 1500 feet. (See section, fig. 3, p. 753.)

In a map published in 1887," from which the distribution of the Plio-
cene beds of Belgium inthe accompanying sketch-map (Pl. XX XIV.)
has been taken, the eminent Belgian geologist M. E. Van den Broeck
has shown a chain of outliers of Diestien deposits, generally capping
isolated hills, extending from Cape Blane Nez, near Calais, where
they attain an elevation of about 500 feet, through Cassel, Tournai,
Grammont, and Brussels to Louvain, at which place, however, they
are not more than 195 feet above the sea. From Louvain, Diestien
strata extend in a continuous sheet, covering a considerable extent
of country tothe N.K. Mr. Clement Reid connects these Belgian and
French beds with those at Lenham, by a belt of outhers of similar
ferruginous sandstone, occurring on the English side of the Channel
near the Chalk escarpment between Folkestone and the river Stour.’
It is considered by M. Van den Broeck that these deposits indicate
generally the southern boundary of the Diestien sea. In passing I
may say that M. G. F. Dollfus, the President of the Geological
Society of France, insists that this sea was closed to the south,? but
the marked resemblance between the molluscan fauna of the Coral-
line Crag (the English equivalent of the upper part of the Diestien
formation)* and that of the Lusitanian and Mediterranean areas at
the present day makes me tenacious of the hypothesis that there
was at the period in question direct communication between the
Anglo-Dutch basin and the Atlantic.’ If the line from Louvain to
Lenham, indicated by this chain of deposits, formed the continuous
margin of the Diestien sea, it may still have been connected with
the south-west by means of a strait over some part of the southern
counties of England.* Whether or not the sea of the Coralline Crag

1 Bull. Soc. Belge Géol. vol. i. pl. 11.

2 «The Pliocene Deposits of Britain,’ Mem. Geol. Surv. 1890, p. 49.

3 Rep. Brit. Assoc. Ipswich (1895) p. 691.

4 While agreeing with Mr. Reid that the Lenham Beds are equivalent to the
ferruginous Diestien Sands of Belgium, the study of the fauna of Lenham leads
me to think that the deposit may be slightly older than the Coralline Crag. The
latter is evidently of similar age to the Belgian ‘zone a [sovardia Cor,’ which
M. Van den Broeck considers to be the upper part, while the sands of Cassel, etc.,
are, in his opinion, the lower part of the Diestien formation. Of the species of
mollusca known from the Jsocardia-beds 87 per cent. occur in the Coralline Crag.

> See Geol. Mag. 1896, p. 27.

6 It may be accidental, but perhaps it is worthy of notice, that the triangular
sbape of the Red Crag area between Saxmundham and Sudbury, with its apex
pointing to the 8.W. (see map, Pl. XXXIV.), seems almost to suggest that a de-
pression, from which the sea was gradually retreating as the southerly elevation
went on, may have formerly existed in that direction.

.

Fig. 2.—Section from Norwich to Yarmouth,
NORWICH BRAMERTON YARMOUTH

CRAG
w CHA x ———

EOCENE

BO Uae DelAW OTS RUNOGROGRUM, = ae ee ee ee ee ee oes a
Fig. 3.—- Section from Norwich to Greenlo.
NORWICH YARMOUTH AMSTERDAM ARNHEM GREENLO

.
.
1 i t t

1 ' !

woyn {CRAG | : | Ets

Recent &||Pleistocene

446 =

p=
---
--—
et
-_—

-
~--.
~~

Sr -—<-7F

-
pee --"

~
=
AS i ron
-—

aide
1500} feet below Ordnance-datum ~nn- 1 Diestlen___—-=-

ae

7o4 MR. F. W. HARMER ON THE [Nov. 1896,

was closed to the north may be regarded as an open question, but
the almost total absence of boreal shells from that formation seems
in favour of the latter view. If this was so, the combined movement
of elevation and depression which followed the deposition of the
Older Pliocene probably created a land-barrier which prevented the
further access of warm currents from the-south, while communica-
tion with northern seas was opened up, and this was probably one
of the causes of the gradual change in the facies of the molluscan
fauna which is characteristic of the Upper Crag.

In Belgium this elevation caused the sea to retreat in a northerly
direction. Diestien strata occur in that country about 25 miles
farther south than do the shallow-water Scaldisien deposits which
rest on them,’ implying in M. Van den Broeck’s opinion a north-
ward shifting of the shore-line previously to the deposition of the
latter, while before the upper beds of the English Crag came into
existence the sea had altogether retired from Belgium. A similar
change in the southern margin of the Newer Pliocene basin, due to
the same cause, may be traced in Kast Anglia. The oldest deposits
of the Upper Crag, namely, those at Walton, are found only at or near
that place,” that is at the southern extremity of the Crag area, the
succeeding horizons of Sutton, Butley, Norwich, and Weybourn, as
pointed out by Mr. Wood and myself many years ago, being repre-
sented by beds occurring successively in positions farther north.

At Antwerp, the Newer Pliocene strata (Scaldisien and Poederlien)
are thinly represented, attaining a maximum thickness of about
12 or 15 feet, and are exposed only below the water-level. They
increase in thickness to the north, and in Holland are covered by
a great mass of still more recent Pliocene and Pleistocene beds,
which rapidly thicken in a northerly direction, and reach at
Amsterdam, if my classification of these deposits be correct, the
extraordinary thickness of more than 1000 feet. Dr. Lorié has
given, in the works before alluded to, descriptions of the strata met
with in borings at Goes, Gorkum, Utrecht, Arnhem, and Amsterdam,
as well as careful lists of the fossils discovered at different depths.
He recognizes at these places, in addition to the recent alluvium on
the one hand, and the Rupelien which was reached at Goes, on the
other, the presence of three formations, namely, ‘ Quaternaire,’ Scal-
disien, and Diestien. Mr. Clement Reid expressed the opinion in
1889 that the Scaldisien deposits of Belgium represent, not the
whole of the Red Crag, but its lowest or Walton stage only, and

1 M. Van den Broeck says, ‘ Le Scaldisien tout entier est lui-méme un dépot
essentiellement cdtier et littoral.’

2 I cannot agree with Mr. Reid (‘Pliocene Deposits,’ etc. p. 85) that the bed
at Beaumont, 5 miles from Walton, described by Mr. J. Brown, of Stanway,
50 years ago, should be referred to the Upper Red Crag. With very few
exceptions the shells recorded from that locality occur at Walton or in the
Coralline Crag, and most of them abundantly. Two northern species are men-
tioned, however, Astarte borealis and Scalaria similis (grenlandica), which have
not been found at Walton ; but the former is not a Red Crag shell at all, having
made its first appearance in the Norwich beds. Mr. Wood had great doubt
whether these specimens had been correctly identified. The sinistral variety of

Trophon antiquus, the characteristic shell of the Walton horizon, occurs at
Beaumont, but not the dextral form.

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. 759

that no beds equivalent to its upper horizons were known either in
Belgium or Holland." A careful analysis of the different faunas
induces me to agree with him as to the two first propositions, but
not as to the third. It seems to me that the upper and by far the
larger of the Dutch beds regarded by Dr. Lorié as Scaldisien are
considerably more recent than that formation:

The resemblance between the Walton Crag and the Scaldisien
(including the Poederlien) of Belgium is very close. Among the
mollusca found at Walton there are 120 which occur abundantly,
and which may be taken as representative species,” and of these 91
are found in the latter deposits. Both are characterized by the
first appearance and the great abundance of the sinistral form of
Trophon (Chrysodomus) antiquus.* The dextral variety has not been
met with in the Scaldisien, and a single specimen of it only in
an upper bed at Walton, but it appears in increasing abundance in
the later beds of the Crag, where the left-handed form becomes
correspondingly scarce.

Among the rarer mollusca of these deposits there are a number of
extinct and southern species,* which were apparently dying out at
that period, as many of them are abundant in the Coralline, but
are not found in the upper beds of the Red Crag. The latter
moreover contain northern shells, including the Arctic forms
Buccinum grenlandicum, Scalaria grenlandica, Amaura candida,
Natica grenlandica, N. helicoides, Leda lanceolata, L. minuta,
and Cardium grenlandicum, which are not known either in the
Scaldisien or from Walton or any older horizon.

In the Poederlien, a slightly newer zone, which has recently been
separated from the ‘Scaldisien by M. Vincent, the dextral form of
Trophon occurs, though not abundantly, associated with a few
specimens of the northern but not exclusively Arctic shell
Chrysodomus despecta, but these are not characteristic of the fauna,
the general facies of which is southern rather than northern.
There is very little difference between the Scaldisien and the
Poederlien. With few exceptions, the species of mollusca found in
them are common to both, and they are not more unlike than the
lower is to the upper bed at Walton. From the latter, as from the
Poederlien, a fauna slightly more boreal than that of the bed under-
lying it has been obtained.’

The following lists show—A, the species abundant at Walton which
are found also in the Scaldisien and Poederlien ; B, the extinct and
southern forms occurring in them, but not in the upper Red Crag
and C, the northern and recent shells characteristic of the latter,
which are not present in the older beds.

1 *Pliocene Deposits,’ ete. p. 211.

* I am indebted for this information to Mr. P. F. Kendall, F.G.S.

®° The Scaldisien was originally called the ‘ Zone a Trophon antiquum.

* 44 extinct and 17 southern in the Scaldisien (including the Poederlien),
and 40 extinct and 11 southern at Walton.

° The distinction between the upper and lower beds at Waiton was first
pointed out by Mr. Kendall,

756 MR. F. W. HARMER ON THE [Nov. 1896,

Tape A,

List of Mollusca occurring abundantly at Walton, which are also
found in the Scaldisien and Poederlien of Belgium.’

-iaté losfa
8.2/8 w ¢ gE|6 «
B/Sle.e| 3s aul fe
ier e| 3 s\s|*=
s\ole" | 8 raisie" |
He |P oD) TD |P4 Io
GASTEROPODA. PELECYPODA.
Cyprea avellana, Sow. ......... +\|+i + Anomia ephippium, Linn. ...... +/+
» europed, Mont. ......... +\/+ ». SUriata, BrOC. cscs +/+
Voluta Lamberti, Sow. ...........- +/+) + Ostrea edits) Timmy apece eee +/+
Columbella sulcata, Sow. ......... +i+y + Pecten pusio, Linn. .............6 +/+
Nassa elegans, Leathes ............ +|+} + »» | Opercularts; Tani: eh seer +/+
55 LAOLOSE | SOV Whices Bawiceioe von +/+} + ~~ maximus, Tinn, <0 eee +\+
(A SOTUSINGLICH, ABYOC. .cecese-: Selle) [bers lle p= 3 tig rinus: IVralll, oe. sere wey
» granulata, Sow. ............ +|---] --- | + | Mytilus edulis, Linn. ............ +/+
5» propingua, Sow. ........... +|+] ? Pectunculus glycimeris, Linn. ....+-|+
5) MEBUCOSE., SOW) ee ccc a sacs vaio +/+} + - var. subobliquus, Wood} +
Buecinopsis Dalei, Sow. ......... +) +] Nucula levigata, Sow. .........++. +/+} +
Buccinuin undatum, Linn. ...... +/+] a tuGloUs, Mini) J..5eeeeee +/+
Purpura lapillus, Linn. ......... +)-+} Montacuta bidentata, Mont. ...J-+/+
z incrassata, Sow. ......[... +f Scintilla ambiqua, Nyst ......... +/+) +
M tetragona, Sow. ...... +/+} + TInucina borealis, Linn. ............ +/+
Trophon contrarius, Linn. ...... +\+] . + 4 Cardita corbis, Phil. ...i.coceeeseae +/+
» gracilis, Da Costa ...... +/+ 3», \seatarts; Leathes:eee +/+
- muricatus, Mont. ...... +/-FI . + | Cardium edule, Linn. ............ +/+
Pleurotoma levigata,? Phil....... +). + a nodosum, Turt. ......... +/+
Ba brachystoma, Phil. ...}-++|-F] » Parkinsoni, Sow. ...... +/+) +
Cerithium tricinctum, Broe....... +\+] + 5 decorticatum, Wood ....+|+} +
» variculosum, Nyst ...}... +} + Cyprina islandica, Linn. ......... +/+
Aporrhais pes-pelecant, Linn. ...)-+|*+ Astarte obliquata, Sow............. +/+) +
Turritella incrassata, Sow. ...... ++...) + » Durtini, de Viaje ee +/+) +
Chemnitzia elegantior, Wood ...J+|---| + » ' Omatit, de Tay ieee +/+} +
ae internodula, Wood .|J+|+] ... | + » Basteroti, de Way. ape +i+} +
Lacuna suboperta, Sow. .. ......J...,FP + Woodia digitaria, Linn. ......... +(+] ...
Natica catenoides, Wood ...... +i+y + Venus casing, Linn... 3,6s.2ee +/+
55. REMICIGUSA, SOW. .......-.].-- +H + Cytherea rudis, Pol... seen +/+]...
,, multipunctata, Lam. Atlee + Artemis lentiformis, Sow. ...... +/+} +
Trochus noduliferens, Wood ...J+|+} + 5, | dineta,aPulit -o.e eee +/+
> | AMUMSCTE BAYT... 0-08 +)+] ... | + | Gastrana laminosa, Sow. ...... +/+] .
st Montacuti, W. Wood...{+'}--- + || Lapes virgineus, Vann. 4...--aeee +}+
» ezeyphinus, Linn. ......J+|+ Tellina crassa, Penn. ..........+- +/+
Fissurella greca, Phil. ............ “| + »» donacina, Vann, s:2 ee +/+] ..
Emarginula fissura, Linn. ...... Hos Abra alba, Wood LLie ee +/+
Calyptrea chinensis, Linn. ..... +/+]. + | Mactra arcuata, Sow. ............ +/+) +
Capulus ungaricus, Linn. ...... +/+} » subtruncata, Da Costa...J+-|}+
Tectura virginea, Mull. ......... +/+]... [Nth] Pandora inequivalvis, Linn. ...J+
Aci@on INGE SOWam wees sss 2 <2 - +/+]. + | Solen ensis, Linn. ................+- +/+
Bulla cylindracea, Penn. ........ +)\-+F] 5 Gladiolus, Gray oceeeeteree +/+].
Conovulus pyramidalis, Sow. ...}...;AY + Corbula gibba, Nyst — .........+. +\+
Dentalium dentalis, Linn. Atit+y ... | + | Corbulomya complanata, Sow. ...J+\+} +
Saxicava rugosa, Linn. .......- +/+
Panopea Faujasti, dela G. A+/+].
Mya arenaria, Linn. ..-.2-6- +/+
9, eruncata, Wints).isaeeee +/+

Cochlodesma complanata, Wood J+}... --

1 In this and the following lists the more abundant species are indicated by thicker crosses. 4
2 [The genders originally adopted in the nomenclature have been retained throughout these lists
of fossils at the author's request.—-Ep. | g

Vol. 52. | PLIOCENE DEPOSITS OF HOLLAND. ToT

Of the 90 species just named 28 are extinct, 19 are southern,
and 2 northern. Most of them, it will be observed, are
abundant in the Belgian beds.

This list shows the close resemblance between the Scaldisien and
Poederlien. The principal difference between them is that in the
latter occur, though not abundantly, the dextral form of Trophon
(Chrysodomus) antiquus, and the northern species 7’r. gracilis and
Tr. despectus.

TasLe B.

Extinct or Southern Species found wm the Scaldisien or Poederlien
of Belgium, but not in the Amstelien or at the Butley horizon of
the Red Crag. (Atl.=Atlantic.)

5 Ss © . 5 efi iS
a | |e ol § [ge MB
Seco eee |S Sie | as
S| Sis? 2 eos] é
m | Ay IO Si te oD)
GASTEROPODA.
Trophon alveolatus, SOW. ......sececeseeeee sel se |i ce bao ee") Se
Cancellaria mitreformis, Broc. ......... +/+ + epee aE
Wassa@ prasmalicd, BVOC, i.sc...s0coeeesoe +) ++ ef +] +
PM TOCHUAOTE, IN GBEUL.. sn acdescieacles ses +/+]... : +
Moree Duponii,. NySt vcer.seccecceeesss- cir | (mers oo | it
Pr MACC THUS: NNISGibn ces ocablvvamtcccwesesee: + . ae
Cancellaria Lajonkairei, Nyst ............ ==) SF ae il 253) eae
‘i umbilicaris, Broc. ......e00...4 + | + et te
Columbella subulata, Broc. ..........6.... +} + PR ill ote
m BMG OWES. a dckiacee stmais «> «a: +]... + +] +
Pleurotoma festiva, Hornes ............... +] +].. we P +
fe GRACIAS, MOmtiicds anette sxenee- +/ 4]... +
2 ESHEETS SAME ee etie dec... <5. a hoped sen ate
va MUCTOSSALG, DUR. ouos0c acess Mra he i ae cells ote
- perpulchra, Wood ...........- +) + y+ + T+
E BIB IS) NY Bh sont sce etme denen + 4 ar ol kim. eon wee P +
2 subulata, NYSt ......se.c0.e00ee: eet SE wee oe
TDiiiianendssas A. Be! 2 kc. hecsbecsaccaas< +/+ 74+)4+)4+ 7+
SES DOEO, MAM cei athiccbacts’ ae cvess «- Sr ioce, | et Sn ee (A
Hedropleura Detheidi, Vin. ..........060+- || ie ay | ee aoe +
Natica cirriformis, Sow. ...0.-<sssscceness +)..04- | +]. i ors
by MEE INCALG. PWM. 525 os Succ tscees Ss ol ee eee ee ee
Turbonilla similis, Wo0d ......ccccccceceed§ oe: +7+f) +)... +
i semistriata, Wood ............ aryl aoe, (ease eae a fi
Kulima subilata,, Don. ......02.00sseenecees +;)/+74+s)+/]4+4...) +
Pyramidella plicosa, Brown ............... Sy) che) Se oe
CEBU TraGhed, MOTI. <iaciiciacsccevcoeses Se eeeanesta? | cast ces’ Ey weet shee

t These are reported from Butley by Mr. A. Bell, but are not recognized as
Butley fossils by Mr. Wood or Sir J. Prestwich.

~I

58 MR. F. W. HARMER ON THE
TasBLeE B (continued).
ae
a | & JEO
lala is
GASTEROPODA (continued).
Scalaria fumbriosa, Wood. .........se.s00008 eee | Pf
~ Frondicula, WO0d — ...0...0..s0+0- f+ | +] +
TAB oe COMLALE, A SOW... sce aracnrute Soares} i+] tit
Fossarus lineolatus, Wood.............000+- +)... +
ivissommaNsOlera@. NV OO inj... cnc. doseeees i+{/+yt+
TORO, ANG oi. oieciatnstes domenee P+ i +i t+
Xenophorus Deshayesi, Mich............... ee eae ioe
Trochus obconicus, Wood ............00000: +/]/+]+
“ Puroimoides, NySt .....<.ceesceree .. | + T+
Capulus obliqguus, Wo00d ..........0.eee00 ++
PELECYPODA.
Pecten tincatus, Da Costa ....s.0sccsseses +) +H]...
Wiomopsis pygmed, hil.) ........5: see Seon (ar
Nucinella ovalis, Wood —.....ssceeeceeceedl | one TO
Leda semistriata, Wood .............-000- p+ |} ++
Wiwemaverenulata, AIA: c.ssccisssasemcceeeon ee | $a t+
Pa CCOrGta, NV OOG |..+.6.cscds-ceenemerennuee ++
Kelh@ coarctata, W000, ...0..6000secesessne +] +]t+
PME, NN OOO. ..20s0 ete ncdeencere oe | + Ht+
Montacuta truncata, Wood ...........-00- +]... +
Lepton depressum, Nyst .........sceeeee0 +)/4+7+
Astarre moerta, WO0d ..c06.ssseseeosee: +i +]...
t conmilowdes;, de Wal. >.. aceacsense + | +...
Pema 0uid,. WOOT)... 3. inser traces + |... | +
y triangularis, Mont. ........0...+=-f +) +i44¢+
Wagesssipiatelia, Nyst- ..2.2s.-4 deen S| ata cas
Coralliophaga cyprinoides, Wood ...... P+) +4] t+
MiclmiameouEpressa, BIOC. 4.-1ssqaeeeeenee Po... | + Pt
PRC ONACING, LAN. siaceceandeeceeeeeeee r+) +7 +
Donanismojmagelis, A Ord. ».....42- sees: ee ul «lope eee
Cuiclusrccniis, Phil.) 2.20. . de ceeedeemenece Wetec) oe ae
Solenocurtus strigillatus, Linn. ........... P+] + y+
Kiracamentricosa, Pil... 2. .sseeeeenees een te oe ees
Cochlodesma complanatum, Wood ...... oe ee) (es
Pandora pind, Mont. 3... ..s.ecceeeeeeer +

| Diestien.

:+4+++ Popol bi t+:

Sof:

PtH!

[Nov. 1896,

Walton
Crag.

Pipi +

++i:

ot known

living.

| N

+t+ti¢i tit

et+t++i +

P+Hti¢ttt+!

+4++i +4:

A large proportion of these are rare in the Scaldisien
and Poederlien.

| Southern.

+ +

++

Vol: 52:1 PLIOCENE DEPOSITS OF HOLLAND. 759

TABLE C,

Species of Mollusca, principally Northern or Recent, found in the
Amstelien or the Upper Red Crag, but not at Walton or in the
Scaldisien of Belgium. (N.A.=North American.)

:
d|5 & bas
24.) [Ss 2 \4
S| aisle [sje 2
£|BO]S/ 8 12) 25
<IP Idina I< >
G-ASTEROPODA. PELECYPODA.
Buccinum grenlandicum, Chem.}...| + §-+-|+] Modiola modistus, Linn. .........}.-. a=
\2 Trophon antiqguus, Linn. ...J+| + ]..-|+] Leda lanceolata, Sow. ............ +
: ef despectus Linn. ...|... a= Sin MD Nsgh SEU/ GIES) COUbM) occ. cs. <eies =F) a
= Sarsii, Jeffr. ......4--- ieee Ae ya UIUC MONG. c..0c.c-sac00e) +
PA Turtont, Bean ......)--- - [--l-Fll » yperborea, Loven ......... f--| +
* PP sealariformis,Gouldj+| + {-++-|-+] Lorines divaricatus, Linn. ...... i+} +
Pleurotoma pyramidalis, Strom.}...| + |...|+] Cardium grenlandicum, Chem. .|+| +
cs violacea, M. & A. ...J.- | + J+\+]? Astarte compressa, Mont. ...... jee)
Cancellaria viridula, Fabr. ......}--- + J++ Zeltine lata, Gmel. ...............].-- a.
Scalaria grenlandica, Chem. ...J.-.| + J+\/+}+ ,, obliqua, Sow. ............ i+) +
Littorina littorea, Linn. ......... +| + » pretenuis, Leathes ...... i+) +
Amaura candida, Moll. .........}--- + J+ Mactra Gualts, SOW. ¢..2.2:-..060-- f...|
= Natica clausa, B. & S. ......... +) + [+\+] 1 Solen siliqua, Linn. ...........j4+| +
BS ee: eek) dues + j+|+
ss elicoides, Johns. ......}--- Site l at
_ occlusa, Wood .........)--- + j.../+ EEG oe ©
Melampus fusiformis, Wood ...}..- + Rhynchonella psittacea, Chem. .}...| +

| Arctic.

+++ $4: +

I do not think that the facts which I have stated leave any room

for doubt that the Scaldisien and Poederlien of Belgium are equi-
valent to the Walton stage of the Red Crag, and not to the whole
of that formation, and that the Butley horizon of the Red Crag is
not represented in Belgium at all. I hope to show, however, that
its equivalent exists in Holland.?

While the Belgian area had thus been converted into land, and in
England the sea had retreated northward from Walton before the
deposition of the later beds of the Crag, an entirely different state
of things obtained in Holland. ‘There the sea-bottom was subsiding,
and we must have in the subsoil of that country a continuous series
of the beds deposited during the progress of the subsidence, equiva-
lent to different stages of the English Crag.* We do find the same

1 These have been found in the Poederlien, but not in the Scaldisien.

* Mr. Kendall has obtained one or two specimens of each of these at Walton,
as the result of many weeks’ work. On the other hand, a number of the
species in this list are among the more abundant forms of the Upper Red Crag
and of the Amstelien.

° Since the above was written, I have noticed that a similar opinion was
expressed in 1872 by Mr. A. Bell, Geol. Mag. p. 211.

* In Belgium a break undoubtedly exists between the Diestien and the
Scaldisien ; but, for the reasons stated, it may have been otherwise in Holland.

| Scandinavian.

+2

+

a

760 THE PLIOCENE DEPOSITS OF HOLLAND. [Nov. 1896.

change in the mollusca of both deposits, namely, the gradual dying-out
of older and southern forms and the gradual appearance of northern
and more recent species. The evidence which we possess from the
Dutch beds is, it is true, at present but small, and, so far as it is
negative, it cannot be regarded as of great value. As to the positive
evidence, the occurrence of certain species at certain depths, the case
is different, and we may draw our conclusions from it with more con-
fidence. It may perhaps be urged that the total number of species
(about 150) is insufficient to form a representative collection of the
mollusca living in these seas during the Pliocene epoch, but if the
view I have elsewhere taken, that the general facies of the fauna of
any bed must be gained from the species which occur abundantly in
it, rather than from all which can be discovered,! these shells may
have more value than at first appears. The chances are that it is
the characteristic forms which have been met with, and it is worthy
of notice that the fauna of each horizon has a distinctive and
probably a representative character.

The section (fig. 4) illustrating the views now held is drawn
to scale from Cassel, a small town in French Flanders, 27 miles
N.W. of Lille, to Amsterdam, a distance of about 150 miles. At
Cassel, Diestien beds are found, resting on Kocene strata (Asschien),
capping the summit of a hill 515 feet above the sea-level. Passing
thence to the N.E., we find, at Ostend, Eocene beds covered by
120 feet of recent and Pleistocene deposits, the latter containing
OCyrena fluminalis,” a freshwater and southern shell which occurs
occasionally in the Upper Crag, but which is very characteristic of
one of the English post-Glacial horizons. No Diestien beds are
present at Ostend, nor was Cyrena fluminalis detected in any of the
Dutch borings.®

Still farther to the N.E., at Goes, in South Beveland, Scaldisien
strata were reached at 114 feet, and Diestien at.183 feet below
Ordnance-datum, at about which depth 20 species of echinodermata
and polyzoa, and 35 species of mollusca, all characteristic forms of
the Coralline Crag, were obtained. Oligocene deposits (Rupelien)
were found at 304 feet, showing the Diestien to be 121 feet in
thickness. Between 94 and 114 feet, a bed was observed containing
Cardium grenlandicum, which Dr. Lorié regards.as Pleistocene, but
I suggest that it may be the equivalent of those which attain
so great a thickness in the other borings, and, | believe, represent
an upper division of the English Crag. Dr. Lorié states that at
Goes no satisfactory division can be made on lithological grounds
between the Pliocene and what he regards as Pleistocene deposits.

In the boring at Gorkum, or Goringhem, about 50 miles E.N.E.
of Goes, the Diestien was not reached, even at a depth of 586 feet.
Between 293 and 382 feet a bed was met with containing land and

1 Geol. Mag. 1896, p. 27.

2 Dollfus, Mém. Soc. Roy. Malacolog. Belg. vol. xix. (1884).

8 T am informed by M. Mourlon that Cyrena fluminalis is found at all levels
in the Flandrien (Upper Pleistocene) of Belgium, deposits which have been
proved by boring to be in places 150 feet thick.

See ee ee

Fig. 4.—NSection from Cassel to Amsterdam.

GORKUM UTRECHT AMSTERDAM

O
>
ees
1)
m
i
je)
a
=|
m7
Zz
\o)
ae
m
~<
2)
=
©)
2)
m
ce?)

Asschien ~~~~~.__

'
1]
i]
1
1
me
i
1
1
1
I

we VW m= mS
Cyrena beds :
300 :
Ypresien
600
900
1200

1500 | feet below Ordnance-datum

762 MR. F, W. HARMER ON THE [Nov. 1896,

freshwater shells, which Dr. Lorié considers to be ‘ Quaternaire.’
Similar species occur at Utrecht and Amsterdam, associated with
marine mollusca of Pliocene age, such as Nucula Cobboldie and
Tellina pretenuis. In the section (fig. 4) I have drawn the base of
the Pleistocene where Dr. Lorié puts it, but I have also indicated by
dotted lines the ‘limits within which land and freshwater species
have been found. Dr. Lorié classes the strata found at Gorkum
below 382 feet as Scaldisien. They contain, however, Leda
lanceolata, and other shells, not known either from Walton or the
Scaldisien of Belgium, and which have not been found in the Dutch
borings in what I consider to be undoubtedly Scaldisien strata. It
seems to me that all the Gorkum beds are newer than the
Scaldisien.

The Utrecht boring was carried down to the great depth of
1198 feet. At this place Dr. Lorié concludes, chiefly on lithological
grounds, that Diestien strata were reached at 775 feet. He points
out that at that depth an abrupt change takes place in the ap-
pearance and character of the sediment, yellow sands, without
glauconite, being replaced by grey sands containing that mineral.}
As, however, the Scaldisien beds of Antwerp and Goes contain
glauconite,” this fact does not seem of sufficient importance to
outweigh the paleontological evidence, which induces me to think
that the division between the Scaldisien and the Diestien should be
placed somewhat lower, namely, at 398 feet, and that the line of
775 feet should be regarded as the division between the Scaldisien
and the more recent beds. Similarity of composition is not always
a conclusive test of age. The material now covering the bottom of
the British seas is not by any means uniform over considerable areas,
while beds which closely resemble each other may be of different
age. ‘The principal part of the material of which the Dutch beds
are composed was, no doubt, brought down by the Rhine and the
rivers associated with it. The nature of these different sediments
would remain more or less the same during long periods of time,
but they might be deposited now in one place, and now in another.’

At Utrecht the freshwater species, Succinea elegans, was met
with between 521 and 542 feet,* at a level (though somewhat
higher) corresponding to that of the bed containing land and fresh-
water shells at Amsterdam, to be alluded to hereafter. Between
513 and 775 feet at Utrecht strata were passed through containing
Nucula Cobboldie, Tellina pretenuis, and the Arctic forms, Leda
lanceolata, Cardium grenlandicum, and Natica clausa, with other
shells representative of our Upper Crag: these deposits seem to me
as recent as the Red Crag horizons of Sutton or Butley. Below
this depth, from 775 to 898 feet, were found what I consider to be

| The yellow colour of the former may possibly be due to the decomposition
of the glauconite.

2 Lithbologically the Diestien and Scaldisien sands are almost identical.

3 Some of the beds described by Dr. Lorié seem to be similar in character to
the Chillesford Clay of East Anglia, though they are of different age.

4 One specimen only was found at 644 feet.

Nol. 52. | PLIOCENE DEPOSITS OF HOLLAND. 763

true Scaldisien strata, containing species characteristic of those
deposits and of the Walton Crag, and especially the representative
form Trophon (Chrysodomus) contrarius, unknown from the Diestien
or the Coralline Crag. Below 898 feet the boring passed through
beds containing the usual Diestien fossils for 300 feet farther,
reaching a total depth of 1198 feet, but not the base of the Diestien
formation.

The borings at Amsterdam, which were carried to a depth of
1098 feet below Ordnance-datum, show that the dip of the Pliocene
and Pleistocene strata continues as far north as that city. The
bed containing land and freshwater shells consequently occurs at a
lower level than that at Utrecht, namely, at about 768 feet.

1 suggest that all the strata below the Pleistocene met with here
(except perhaps the last 48 feet, which do not contain fossils)
represent an upper zone of the English Crag, and that the Scaldisien
was not reached. In addition to most of the boreal species recorded
from this horizon at the other localities, there were found in this
boring Leda myalis, a characteristic shell of the latest Pliocene
beds, Leda minuta and Fusus scalariformis.* Northern shells occur
at all depths, though they become less abundant in the lower beds,
and there is a marked absence of the Coralline and Walton Crag
forms which are present in the Scaldisien.

The greater-part of the Newer Pliocene deposits of Holland are
thus, I consider, decidedly more recent than the Scaldisien of Belgium.
They cannot be included in that formation because they are sepa-
rated from it by the Poederlien, a zone which closely resembles the
Scaldisien, but differs widely from these deposits. I know of no
horizon to which this grand series of strata, more than 400 feet in
thickness, can be conveniently referred, and therefore propose for
it the name of ‘ Amstelien.’”

It does not seem probable that these Amstelien beds contain any
which are equivalent to the Norwich Crag. Some of the common
shells of that horizon occur in them, but the most representative, as
for example, Astarte borealis, A. compressa, A. sulcata, Tellina lata,
Natica catena, and NV. helicoides, are conspicuous by their absence.
The list of shells from the Amstelien is, however, evidently incom-
plete, and these species may possibly be discovered in a future boring.
But there is not at present any paleontological evidence by which
this formation can be divided into zones, except that land and
freshwater shells occur only in the upper part.

If the new zone, Amstelien, which 1 now propose, is generally
accepted, it will, I think, involve the separation of the Walton bed
trom the Red Crag, but I have for some time thought that separation
desirable. The difference between the faunas of these two deposits

1 The shells from the boring at Arnhem were not preserved, with the
exception of a few specimens of recent species, which were found at a depth of
429 feet.

2 The name ‘ Amstelien, suggested to me as an appropriate one by Dr. Lorié,
is taken from that of the river Amstel, upon which stands the city of Amsterdam,
where these beds have their greatest known development.

Q. J. G. SiNo. 208. 3Fr

‘764 _ MR, F. W. HARMER ON THE [Nov. 1896,
is considerably greater than that between the upper portion of the ~
‘Red and the Norwich Crags.

I have been guided entirely by paleontological considerations in
attempting to separate, in these borings, the different horizons of
the Dutch Crag. The lines that I have drawn may or may not be
correct, and I am quite prepared to adjust them if necessary. But
even if they may have to be shifted higher or lower, it will not, I
think, affect the general conclusions, that three divisions rather than
two may be traced in these strata; that Arctic shells are confined
to the highest zone; and that there is an absence from the latter of
a number of extinct or southern forms which are found alike in
the Scaldisien and Walton deposits, but not in the upper horizons
of the English Crag.

The difference between the three divisions of the Dutch Crag
comes out more distinctly when we confine our attention to the
more abundant or characteristic species. I subjoin lists of these,
extracted from the general list given by Dr. Lorie.

List of the more abundant species of Mortusca from the
PuiocenE Brps of Hornanp.

A. From beds regarded by me as Diestien.!

Terebratula grandis, Blum.
Anomia ephippium, Linn.
Pecten opercularis, Linn.

» ventilabrum, Goldf.
Limopsis pygmea, Wood.
Cardita orbicularis, Leathes

» chameformis, Leathes
» scalaris, Leathes

Astarte Omalii, de Laj.

» triangularis, Mont.
Woodia digitaria, Linn.
Venus ovata, Penn.

Corbula gibba, Olivi
Dentalium entalis, Linn.
Cyprina islandica, Linn.

These are all Coralline Crag shells and exceedingly abundant in
that formation. In addition, there have been found in these beds
35 species of mollusca, 11 of polyzoa, and 3 of echinodermata,
characteristic forms of the Coralline Crag.

B. From beds regarded as Scaldisien.

Anomia ephippium, Linn.
Pecten opercularis, Linn.

» similis, Laskey

» ventilabrum, Goldf.
Mytilus edulis, Linn.
Cardita chameformis, Leathes

» scalaris, Leathes

» orbicularis, Leathes
Astarte Galeotti, Nyst

» Omalii, de Laj.
Woodia digitaria, Linn.

Cyprina islandica, Linn.
Venus ovata, Penn.
Mactra, deaurata, Turt.
Corbula gibba, Olivi
Dentalium entalis, Linn.
Turritella terebra, Linn.
iy incrassata, Sow.
Fusus gracilis, Da Costa,
» contrarius, Linn.
,, alveolatus, Sow.
Nassa reticosa, Sow.

Tellina compressa, Natica helicina, Nassa elegans, Fusus antiquus
(dextral), and Nucula Cobdoldie, Red Crag or Scaldisien, but not
Coralline Crag forms, are met with at this horizon; with one

1 For convenience of reference I use the names adopted by Dr. Lorié.

DViok: 525]

Crag.

| ood

PLIOCENE DEPOSITS OF HOLLAND. (

65

exception the species in this list occur in the Scaldisien or Walton

Anomia ephippium, Linn,
Pecten opercularis, Linn.

» ventilabrum, Goldf.
Mytilus edulis, Linn.
Nucula Cobboldie, Sow.

» levigata, Sow.
Leda lanceolata, Sow.

» myalis, Wood
Cardium edule, Linn.
subturgidum, d’Orb.

bP]

33

Incina divaricata, Linn.
Cyprina islandica, Linn.

grenlandicum, Chem.

C. From beds regarded as Amstelien.

Donax vittatus, Da Costa
Tellina obliqua, Sow.

» pretenuis, Leathes
Semele alba, Wood
Mactra solida, Linn.

5 deaurata, Turt.

» subtruncata, Mont.
Mya arenaria, Linn.

» truncata, Linn.

» Bingham, Turt.
Corbula gibba, Olivi
Turritella terebra, Linn.
Littorina littorea, Linn.

‘but in the absence of many characteristic Walton species.

Venus ovata, Penn. Ringicula ventricosa, Sow.

These are, with one or two exceptions, among the most abundant
and characteristic species of the upper horizons of the English Crag.
In addition to the above, the following have been found in the
Amstelien, though not abundantly :—Leda minuta, Natica clausa,
and Fusus scalariformis, Arctic shells, and Scrobicularia piperata, an
Upper Crag form.

The fossils named in Table A are evidently Diestien, while
Table B contains the same kind of admixture of Coralline and
Red Crag forms that is characteristic of the Walton bed, which it
resembles generally more nearly than any other horizon of the

Crag.

The difference between Tables Band C is very marked. The
first contains four characteristic southern shells, and one exclusively
northern (found also at Walton); the other, one southern (an Upper

Crag species), and four northern forms, two of the latter being Arctic.

The fauna of Table C presents a more recent facies, resembling
that of the Butley Crag, not merely in the presence of boreal shells,
No one
familiar with the English Crag would regard this list of mollusca

(Table C) as representative of the Walton zone.

The following analysis of all the species of mollusca found at
‘Walton, in the Scaldisien and Poederlien of Belgium, and in the
Amstelien of Holland will show, on the one hand, the close resem-
blance of the three first, and on the other, the great difference

‘between these beds and the latter.

Not known Cor. Crag

living. or Diestien. Southern. Northern.
Walton Wei... 36 °/, TS}, 19 %/, 55 '/s
Sealdisien ......... Bt oh (lin rd 2:Bif,
Poederlien ......... 42 °/, 73 ly Lge) 5 46 °/,
Amstelien ..... ... 30 °/, 63 |, 6:80 /5 13°70 fa

1 From information kindly supplied to me by Mr. Kendall. The Walton

-analysis is taken from the fauna of both the upper and the lower beds.

oF2

766 MR. F, W. HARMER ON THE [Nov. 1896,

The difference between the three former and the latter would be
much more marked, if we could confine ourselves in each case to
the characteristic species.

Among the many exposures of Crag, both in England and on
the Continent, we may have deposits representing any part of the
Newer Pliocene period, and it is not possible to say that a fossili-
ferous bed found at any one spot is the exact equivalent of one
met with elsewhere, nor to decide in all cases the exact order of
superposition of the different deposits ; but when we compare, for
example, such horizons as the Walton and Butley Crags, the
distinction is evident. And there is the same kind of difference
between the Scaldisien deposits of Belgium and those for which I
propose the name of Amstelien. Looked at broadly, the beds of the
Upper Crag of England arrange themselves somewhat in the
following order: Walton, Sutton, Butley, Norwich. It cannot be
said with certainty that any Belgian or Dutch zone is precisely
equivalent to any portion of the English Crag, but the fauna of the
Scaldisien and Poederlien resembles most nearly that of the Walton
beds, and that of the Amstelien those from Sutton or Butley.

Each division of the Dutch strata increases regularly in thickness
in a northerly direction. The Diestien beds, which at Goes are
121 feet, at Utrecht, 65 miles to the N.E., are more than 300 feet
thick. The Scaldisien increases in the same distance from 69 to
123 feet, while the Amstelien is 262 feet thick at Utrecht, and
more than 450 feet at Amsterdam. At this point, the farthest to
the north to which we can carry it, this increment shows no sign
of abatement.

The depression in which the Pliocene strata of Hollana rest appears
to be of the shape of a shallow basin, the sides of which rise to
the west, east, and south, towards Norfolk, Germany, and Belgium
respectively. Two sections (figs. 3 & 4, pp. 753, 761) illustrating
this point are given, namely, from W. to E., and from 8. W. to N.E.;
but if a third were taken, from S.E. to N.W., that is, from Diest
towards Antwerp, it would also show the strata inclining towards the
deepest portion of the basin." They are naturally thickest there, but
none of them give any indication of having originated in deep water,
the presence in the Amstelien of shells such as Mytilus eduhs, Cardium
edule, Donax vittaius, Mactra solida, Mya arenaria, Solen siliqua, Scro-
bicularia piperata, Purpura lapillus, and Littorina littorea pointing
plainly in an opposite direction.* The present case is not one in
which sediment has filled up a deep and pre-existing depression, but
where the bottom ofa shallow sea has continued to subside, part passu
with the accumulation of the material brought down into it.*

1 [ was equally surprised and interested, when constructing these sections, to
find how accurately the details of the different borings fitted in with each other,
and with the views expressed in this paper.

2 The considerable thickness of some of the beds of the Upper Crag in
Suffolk, which contain a shallow-water fauna, shows that subsidence was going
on there, though not so rapidly as in Holland.

3 T have no desire to enter here on the discussion of the disputed question
whether the accumulation of great masses of sediment in the form of deltas:
causes the subsidence of the sea-bottom on which they have been deposited.

~ Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND, 767

' TIT. Tae GroerapnicaL Conpitions oF THE AngLio-Dutca AREA
DURING THE VARIOUS STAGES OF THE Priocenr Epocnu.

In one of the maps accompanying this paper (Pl. XX XTYV.), I have
sketched hypothetically, and as far as the evidence will allow, what
I consider may have been the distribution of land and sea at the
different stages of the Pliocene era. I have taken the lines drawn
by M. Van den Broeck as representing approximately the southern
limits of the Diestien and Scaldisien basins. I have followed
Mr. Clement Reid in connecting the former with Lenham, but I
have ventured to bend the line to the 8.W. beyond that place, as a
suggestion of the manner in which the sea of the Coralline Crag may
have communicated with the Atlantic. I have shown the southern
limits of the sea of the Walton Crag as occupying a position similar
to that of the Scaldisien and Poederlien in Belgium, for it appears
probable that the elevatory movement which in that country carried
the shore of the Scaldisien sea to the north would in the same manner
have affected the English area. The sea of the Walton Crag may
possibly have extended over the district now occupied by the Sutton
and Butley deposits, traces of its former existence having been
removed by denudation, or being concealed below the water-line,
but it seems unlikely that it covered those parts of Norfolk in
‘which occur the fluvio-marine strata of the Upper Crag.*

The southern boundary of the Amstelien, and of the Upper Red
Crag of Suffolk, is drawn to the north of that of the Scaldisien.
The Amstelien beds do not extend into Belgium,’ and in Holland
they give indication of thinning out to the south, while in Suffolk
the Red Crag of Butley originated, if not as a beach or foreshore-
deposit, at any rate at no great distance from the coast.

It appears that after the deposition of the Amstelien beds, that is,
at a period not later than that of the Norwich Crag, the subsidence
of the Dutch area was arrested, and land conditions were established.
Tt does not seem that any deposits representing the latest horizons
of the English Crag were found in these borings, as the eastern
margin of the Pliocene sea had been by that time shifted, in con-
sequence of the elevation of the area in question, to the west of the
present coast of Holland. Part of the western (the East Anglian)
portion of the Pliocene basin was still submerged, and from the strata
there deposited some information may be gained as to the geo-
graphical conditions of this period.

Mr. Wood and I formerly regarded the Norwich Crag as estuarine,
‘but I now think that it may have originated in a shallow bay, or
the embouchure of an estuary,’ which, however, did not extend so
far southward as did the sea of the Butley Crag. The general,
though comparatively infrequent, occurrence of land and freshwater

+ Some of the beds met with in Suffolk in the deep boring at Southwold,
under the Norwich Crag, may possibly be of Red Crag age.

2 M. Mourlon has kindly allowed me to examine the material obtained by
the officers of the Belgian Geological Survey from borings in the north of that
country, but I have been unable to detect the presence of the Amstelien beds
there.

3 See Godwin-Austen, Quart. Journ, Geol. Soc. vol. vii. (1851) p. 129.

768 MR. F. W. HARMER ON THE [Nov. 1896,.

shells in beds of Norwich Crag age seems to show that a river
discharged into this bay, and the occasional presence of specimens of
Cyrena fluminalis, a species now inhabiting the Nile,” as well as of
mica and Rhenish pebbles, indicates that this river flowed from
the south.” An interesting indication of the shore-line of the Crag
sea occurs at Hoxne, in the Waveney Valley, where, at the most
westerly point to which the Norwich Crag has been traced, the
Chalk rises suddenly in the form of a cliff.’

The enlarged map of Kast Anglia (Pl. XX XY.) shows the western:
limit of the area within which exposures of the Norwich Crag are
found, and it does not seem probable that the sea of this period.
extended to any great distance beyondit. Its eastern margin cannot
be traced, as in that direction the Crag beds dip below the water-level.*

In the typical section of Norwich Crag at Bramerton, there is an.
upper bed, similar lithologically to the lower one, but containing
a rather more boreal fauna, the northern species, Astarte borealis,.
being more common in it, while littoral forms are comparatively, and
fluviatile exceedingly, rare. This somewhat more recent and-
deeper water-bed implies a slight subsidence, and this would have
carried the bay farther to the west. Hence, some of the deposits
near the margin of the area; or those, like that at Aldeby, from.
which freshwater shells are absent, or nearly so; or the beds which
immediately underlie the Chillesford Clay, may be of the age of the:
upper rather than of the lower bed at Bramerton. It is difficult,
however, to find any marked paleontological difference between
the various deposits of the Norwich Crag series, and I have not
attempted on the map to distinguish between them.”

The Chillesford Clay, the deposition of which followed that of
the Norwich Crag, has been from the very first a veritable apple of
discord, and the controversies that it has excited have by no means
ceased. Mr. H. B. Woodward, studying this formation in the
district near Norwich, where it is not well represented, and seems
sometimes to be interstratified with other beds, has come to the
conclusion that it does not represent any definite geological horizon ;.
but against this, his colleague, Mr. Whitaker, who worked in Suffolk,.
where such difficulties do not exist, protests. Mr. Clement Reid,

1 Cyrena fluminalis is also found in Thibet and China (S. V. Wood, Jun.,
Quart. Journ. Geol. Soc. vol. xxxviii. 1882, p. 694) and in some of the rivers of
Central Asia.

2 The presence of land and fiuviatile shells, together with Rhenish pebbles,.
etce., in the Norwich Crag over so large an area as that from Aldeburgh to-
the Bure Valley, seems to show that the rivers of Central Europe were, at this-
period, working themselves round to the western side of the Pliocene basin.

3 See Clement Reid, ‘ Pliocene Deposits of Britain,’ p. 112.

4 It is much to be regretted that H.M. Geological Survey does not attempt:
more systematically to clear up doubtful points of this kind by boring. Every
square mile of the Belgian Geological Survey maps contains information.
obtained in this way.
~ ? Mr. Wood and I formerly called the Norwich Crag deposits which appeared
to be more recent than the lower bed at Bramerton ‘Chillesford Crag.’ It
seems better merely to refer any which can be shown to be so to an upper zone
of the Norwich series. ;

Vol, 52, | PLIOCENE DEPOSITS OF HOLLAND, 769

while recognizing the Chillesford Clay as distinct, thinks that it may
be equivalent to the Weybourn and Belaugh Crag (referred to
below), but the extraordinary abundance of Yellina balthica in the
latter, and its entire absence from the former, seem to me strongly
opposed to that view. At Belaugh and Weybourn more than half
the specimens present are those of this species. The Chillesford
Clay is not often fossiliferous, but where it is, although other species
of Tellina commonly occur, this form has never been found.

I am far from thinking that every example of laminated clay in
Kast Anglia should be referred to this horizon. At the same time
there are a number of sections of what Mr. Woodward calls ‘ good
Chillesford Clay,’ as to which no doubt has ever been expressed,
which were originally regarded as such by Sir J. Prestwich, and
which were so mapped 25 years ago by Mr. Wood and myself, and
since then by different officers of H.M. Geological Survey. These
exposures show that the Chillesford Beds are in places nearly 20 feet
in thickness, and that they maintain for nearly 70 miles their
distinctive character. They seem to me not only to form a definite
geological horizon, but to mark a decided change in the geological
condition of the Pliocene basin.

The abrupt change, first from the sands of the Norwich Crag,
full of drifted and comminuted shells, to the finely laminated
micaceous clays of the Chillesford Beds which rest on them, and then
to the newer and overlying pebbly gravels is, I think, capable of
explanation.

Beds of clay and mud can only originate in quiet water, either at
a depth too great to be affected by the movement of tides and
currents, or in a position sheltered from their influence. They are
especially characteristic of the tidal estuaries of flat countries, being
deposited in slack water on the top of the tide, not so much in the
channels in which the current flows as upon banks on either side of
it, which are alternately covered and uncovered by water. On these
the mud quietly settles in the form of films and thin lamine. The
character of the sediment may vary with the season. During the
floods of winter the water is often turbid with the coarser matter
which it contains, while in dry weather the suspended material is
of afiner character. It is, moreover, in the higher reaches of the
estuary, where the scour is least, that banks of clay principally
accumulate; these are eventually raised above the level of the
water, and form marshes bordering the stream. Towards the mouth
of the valley such beds become intermittent, and the mud is inter-
stratified with sand and gravel.’

Shalion tor deposits of clay and silt are not, however, entirely confined
to estuaries. Reference should perhaps be made to the alluvium which fringes
the eastern margin of Lincolnshire, connecting the estuarine beds of the Humber
with those of the Wash, but the destruction of the Holderness coast, which
has been so long, and is still, going on, makes it probable that the left bank
of the Humber formerly extended farther south than it does at present, so
that to some extent the Lincolnshire alluvium may be of estuarine origin.

Scrobicularia piperata, a poe common in muddy estuaries, is characteristic
of these beds.

770 | . MR. F. W. HARMER ON THE [Nov. 1896,

There is no reason to suppose that the Chillesford Clay is a deep-
water deposit, but it corresponds very closely with the hypothesis
of its estuarine origin. It is composed either of unstratified clay, of
a character similar to that of mud produced by inundation, or of fine
alternating lamin of sand and mud, being more clayey and easy to
trace in one part of the area, and becoming more sandy, less
micaceous, and somewhat more difficult to map in the other. The
absence from it of an estuarine fauna has been commented on.
It rarely contains shells, however, but when it does they are the
shallow-water forms of the Norwich Crag, and of a character not
unlike those which may now be found along the banks of the
estuaries of Suffolk. The skeleton of a cetacean, 30 feet long,
was found at Chillesford, and this may have been brought up by
the tide, and stranded at low water. Such an occurrence is by no
means infrequent at the present day: Hyperoodon rostratus has
been taken in the Thames at Barking and Millwall, and the grampus
at Battersea, and in the Humber nearly 40 miles from its mouth.

The Chillesford Clay may thus indicate an elevation of the Norfolk
area, by which the sandy bay or inlet of the Norwich Crag became
land, and a muddy tidal estuary, similar to those of the East of
England or of Holland at the present day, but on a larger scale,
established itself in Hast Anglia. Mr. Wood and I formerly believed
that this estuary opened to the south, but I now think that the con-
trary was the case. Mica, which forms the most constant and
characteristic feature of these deposits, commonly occurs in the
Dutch beds, having been brought down by the Rhine and the Meuse
from the Devonian and Carboniferous schists which occur in the
region drained by those rivers. Pebbles of white quartz and other
rocks similar to those of the Rhenish and Mosean drifts of Holland
may be found in the Chillesford Clay, as indeed in all the Pliocene
beds of Norfolk.

Although the sea had at this time retired both from Holland and
Kast Anglia, the Rhine must have continued to discharge into the
North Sea, and the estuary of the Chillesford Clay may have formed
one of the channels by which it did so.* It does not seem im-
probable that the Rhine may have been diverted towards the
western side of the Pliocene basin, as a slight subsidence of Suffolk
took place at this period, and carried the Chillesford Beds over a
district which was dry land during the deposition of the Norwich
Crag.

I have shown in the map (Pl. XXXIV.) the possible connexion
between the Rhine and East Anglia, but it will be further seen
that, if all the exposures of these beds which are recognized as such
by the officers of the Survey and myself be taken, they arrange
themselves in a sinuous line from Walton-on-the-Naze in Essex to
Mundesley on the Cromer coast. I do not wish to press the point
too far, but I think that this can hardly be accidental, and that it

1 In every case where the Rhine is mentioned, it is understood to include
the affluents of that river, and especially the Meuse, from which much of -
Southern Drift of Holland seems to have been deri ved,

iil

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—_— —_—

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. (ii
deserves to be noticed. The Chillesford Beds have no doubt been
exposed to considerable denudation ; at the same time the dotted
lines which I have drawn may indicate approximately a part at least
of the tortuous course of this ancient estuary." Beyond these limits
there occur in places thin layers of laminated clay, the age of which
is doubtful. If these are of Chillesford age they may have been
deposited in time of flood beyond the usual channel, or the stream
may have changed its course from time to time. It is possible also
that the Chillesford Beds may be present below the water-level in
some part of East Norfolk, but if so they are the marginal deposit
of a wider body of water than that which is suggested on the map,
and their supposed boundary to the east must be shifted accordingly.
On the whole it seems more probable that the abrupt change from
sand to clay, and again from clay to the beds of gravel next to
be described, was due to some alteration in the geographical con-
ditions of the East Anglian portion of the Pliocene basin, such as
the substitution of an estuary for a bay, rather than to a difference,
from some unexplained cause, in the character of the sediment
brought into the area.

It is in Norfolk—that is, towards the mouth, as it seems to me, of
the supposed estuary of the Chillesford period—that the beds occur
upon which Mr. Woodward lays so much stress. In that district
eases are occasionally met with where laminated clay is inter-
stratified with sand and gravel, sometimes apparently of Norwich
Crag age, but which at other times seem to belong to the later
period of the pebbly series. One such case especially occurs to me,
that at Hartford Bridge, 2 miles south of Norwich, to which I called
Mr. H. B. Woodward’s attention and which we visited together
many years ago. This was figured by him,’ but at present it
indicates still more plainly the connexion between the Chillesford
Clay and the Bure Valley Beds. The section now shows 10 feet
of laminated brick-earth, more sandy than the typical Chillesford
Clay of Suffolk, interbedded with fine pebbly gravels containing a
considerable admixture of stones of southern origin. It seems to
me that these beds may belong to a period when the submergence
which afterwards carried the sea of the Bure Valley Crag (referred
ito below) over a considerable part of Norfolk and Suffolk was com-
mencing, but before it had proceeded far enough to put an end
altogether to the deposition in places of laminated estuarine beds
containing mica brought down from the south. The beds present
in the Hartford Bridge section may thus be intermediate between
the Chillesford Clay and the Bure Valley Crag, and it is not difficult
to understand that there may be others, although it may not be
easy to distinguish them, which similarly connect the Chillesford
Clay with the Norwich Crag.

Succeeding the Chillesford Clay are some fossiliferous beds of sand
and pebbly gravel, composed principally of flint, but containing, as

1 Estuarine deposits not only imply an estuary, but also indicate the position

which it occupied.
2 Mem. Geol. Surv. Norwich, 1881, pl. iii. fig. 7.

772 MR. F, W. HARMER ON THE [ Nov. 1896,

pointed out by Sir J. Prestwich," much southern drift. These
occur at Weybourn on the Norfolk coast, at Wroxham and Belaugh
in the Bure Valley, and at Crostwick and elsewhere near Norwich.
In these appears for the first time, and, as before stated, in great:
abundance, Tellina balthica, a shell unknown from any older horizon
of the English Pliocene.? They were originally described by
Mr. Wood and myself as the Bure Valley Beds, and, with some
unfossiliferous gravels which have a considerable development in
Norfolk and Suffolk, are shown in our map of the Crag district ° as
the base of the Lower Glacial formation. Sir J. Prestwich after-
wards adopted for them the name of ‘ Westleton Shingle,’ including
the deposits at Belaugh and other places in the Bure Valley, but
excluding that of Weybourn, which he referred to the Norwich
Crag. I know of no sufficient reason, however, for such a separation.

The Bure Valley and Weybourn Beds are evidently Pliocene
rather than Pleistocene,* as pointed out by Messrs. Woodward’ and
Reid,° but I think it possible that some of the pebbly gravels asso-
ciated with them by Mr. Wood and myself may be of Pleistocene
age. Considerable difference of opinion exists between the officers
of H.M. Geological Survey on this subject. Mr. H. B. Woodward
believes that the gravels of Westleton, Henham, Halesworth, and
Haddiscoe in the north of Suffolk are glacial, while he regards
those of Loddon and Heckingham in the south of Norfolk as of
the age of the Crag." Mr. Whitaker does not agree with this view
of the case,” and my own experience when mapping the district
leads me to doubt whether any such division can be traced.

The Bure Valley Beds seem to me to indicate that after the de-
position of the Chillesford Clay the sea re-invaded the north-eastern
portion of Norfolk and probably of Suffolk, forming a bay into
which the Rhine still continued to discharge. Mr. Reid has shown,
however, that during the later part of the period represented by the
most recent of the Pliocene beds on the Cromer coast, an Arctic
climate prevailed, and probably no great interval of time separated
them from the Pleistocene era. During the accumulation of these
Cromer Beds, as I think the Pliocene deposits newer than the
Weybourn Crag might conveniently be called, the sea retired from
East Anglia, but it seems to have returned before the deposition of
the Lower Glacial Clays, and it may then have re-occupied under

1 Quart. Journ. Geol. Soc. vol. xxvii. (1871) p. 477.

? For many years some specimens of Tellina balthica have been exhibited
in the Natural History Museum at South Kensington, labelled ‘Postwick,’ a
Norwich Crag locality, and Sir J. Prestwich gives this species, with a query,
from the same place. In both cases Crostwick should be substituted for
Postwick. See Trans. Norf. & Norw. Naturalists’ Society, vol. ii. p. 377.

3 Suppl. Crag Moll. vol. iii., Palzeont. Soc. 1872.

4 Messrs Gunn and Savin discovered the Tellina balthica-Crag beneath the
freshwater bed at Runton in 1876, Proc. Norw. Geol. Soc. vol. i. p. 50.

° ‘Geology of England and Wales,’ 1876, p. 281.

8 « Pliocene Deposits of Britain,’ Mem. Geol. Surv. 1890, p. 222.

7 Mem. Geol. Surv. Norwich, 1881, p. 85. Mr. Woodward’s views on ae
Bure Valley Beds are further given in Geol. Mag. 1882, p. 452.

8 Mem. Geol. Surv. Southwold, 1887, pp. 25 & 382.

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. ae

somewhat similar conditions a similar area. If this wasso we may
perhaps provisionally regard the pebbly gravels of East Anglia as
one, though not a strictly continuous formation, the greater part of
them being older, while perhaps some of them are newer than
the Cromer Beds. It does not seem possible to map them in any
other way, as it is almost impossible to distinguish between such
deposits. While, therefore, the position of the Weybourn and Bure
Valley Crag can be correctly ascertained, all that can be said with
certainty as to some of these unfossiliferous gravels is that they are
newer than the Chillesford Clay and older than the Contorted
Drift.’

Sir Joseph Prestwich correlates his Westleton Series with some
gravels in the South of England, principally on the ground that
they contain pebbles of a similar character. Without expressing
any opinion as to the correctness of this view, I may again suggest:
that this does not necessarily imply that these deposits are syn-
chronous.

No strata equivalent to the Weybourn Crag have been met with
in the Dutch borings. Tellina balthica oceurs in the upper part,
but in beds which Dr. Lorié regards as post-Glacial.*

The deposition of the Weybourn and Bure Valley Crag was:
followed by that of the strata which have been so admirably worked
out by Mr. Reid, generally known by the unfortunate name of the
* Forest Bed Series.’ ‘These deposits, from which so many remains
of mammalia have been obtained, are exposed only along the coast,
and do not extend to any great distance inland. Consisting of
freshwater, estuarine, and marine deposits, they represent a late
stage in the Pliocene period, and the final emergence of Hast
Anglia from the Pliocene sea. It is, perhaps, worthy of notice that
the south-western margin of the area occupied by these beds is
roughly parallel to that of the Chillesford Clay, and the conditions
under which the earlier portions of them were deposited may have
been similar. From Holland to Norfolk at least the basin of the
North Sea had been converted into land, while an estuary occupied
a position similar to that of the Chillesford Clay, but somewhat
farther to the east. The river which flowed into this estuary came,
as did that of the Chillesford Clay, from the south,’ and brought
with it not only the drifted and fragmentary portions of skeletons
and teeth of mammalia (principally elephants), including the
hippopotamus, and other forms characteristic of a warmer climate
than that which obtained generally during the Newer Pliocene period,
but also the southern shells Cyrena fluminalis, Hydrobia marginata,

1 Mr. H. B. Woodward says that the beds at Westleton are newer than the
Lower Glacial Brick-earth.

? This species is included in Dr. Lorié’s list of fossils from Utrecht, but
both Mr. Reid and I have examined the specimens, and think that this is a
mistake.

3 See also Reid, Mem. Geol. Surv. Cromer, 1882, p.57. This river must have
passed over some part of Holland, and at some future time the equivalent of
the mammaliferous beds of the Cromer coast may be met with in that countr y-

774 MR. F. W, HARMER ON THE [Nov. 1896,

and Lithoglyphus fuscus.' Bones of the musk ox and glutton, animals
now confined to northern latitudes, are also found, and indicate
possibly more nearly the temperature then prevailing in Norfolk.
Many stools of trees such as now inhabit Great Britain occur in the
so-called Forest Bed, but these have all been drifted, perhaps some
distance, and possibly from the south.”

More than once during the deposition of the Cromer Beds the
estuary was shifted to the east, and the low-lying land from which
the salt water had retired was occupied by fluviatile deposits and
tenanted by a flora similar, as Mr. Reid has shown, to that of the
Norfolk broads at the present day. Once more the sea advanced
upon the north-eastern margin of Norfolk, leaving behind it, on its
retreat, sands containing the northern shells Leda myalis and
Astarte borealis. These sands again were covered by freshwater
beds, in which occur leaves of the Arctic forms Betula nana and
Salix polaris, and this Arctic freshwater bed forms a link connecting
the Pliocene with the Pleistocene period.

With the latter a renewed subsidence of Holland commenced,
almost equal in importance to that of the Pliocene era, for at
Amsterdam the Amstelien is overlain by more than 600 feet of
recent and Pleistocene deposits. The relation of the Glacial beds of
the Low Countries to those of England presents an interesting and
important field of enquiry, but one which cannot be entered upon
in this paper. It may perhaps be noticed, however, that no
deposits of character similar to that of the Till or Contorted Drift
of Norfolk have been met with in the borings here described. In
_ Drenthe, to the N.E. of the Zuiderzee, in the island of Texel, on

the coast, and in Urk, beds of hard Till occur which I have not
seen, but as to the glacial character of which Dr. Lorié entertains
no doubt. Extending somewhat farther to the south there exist,
some miles west of Utrecht, steep hills of sand and gravel which
seem to be the terminal moraine of the Scandinavian ice-sheet.
In a deep railway-cutting which I visited with Dr. Lorié contortions
were to be seen closely resembling those of the Norfolk cliffs, and,
within the space of a few hundred yards, as many large boulders
as could be found at any one time on the beach between Wey-
bourn and Cromer. The south-western limit of the Scandinavian
Drift in Holland is marked on the map (Pl. XXXIV.) by a dotted
line.

The ice-sheet by which Drenthe and the eastern provinces of
Holland were invaded came from the Baltic, and not from Norway,
since the erratics found in them are Swedish and not Norwegian.
It does not seem that the Scandinavian ice-stream penetrated
to the Dutch coast, except in the north as before stated, the

1 No perfect skeletons occur in the Cromer Beds. With few exceptions
(one of which Mr. Reid considers derivative), remains of the larger mammalia
are confined to the estuarine deposits.

2 Mr. Reid, however, has found leaves of the oak, etc., which could hardly
have been drifted, in some of the Cromer Beds. The climate of this period

seems to me to have been milder than that of the Upper Crag, although glacial
‘conditions may have come on somewhat rapidly towards its close.

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. 775

Pleistocene deposits of Utrecht and Amsterdam being composed
of stratified gravels and sands. It is difficult, therefore, to see how
the Baltic glacier could have reached Kast Anglia, theugh ice-floes
with Scandinavian boulders might easily have done so, while had the
Norwegian ice filled the North Sea and overflowed the county of
Norfolk, some evidence of its presence ought to be found in the
Glacial beds of Holland.

The great thickness of the Amstelien as compared with the
Scaldisien strata is perhaps worthy of notice, but whether it may be
taken as an indication of the comparative duration of these periods,
or only of the comparative amount of sediment brought down by the
rivers draining into the Pliocene sea, cannot be decided.

Some of the shells found in the Amstelien beds are not merely
British species with a northern range, but boreal forms, which are
not now found beyond the limits of the Arctic Circle. The climate
of Northern Europe was at that time considerably colder than it is
at present, and the glaciers of the mountain districts drained by the
Rhine were on a larger scale, with probably a corresponding increase
of the sediment brought down by it.’

When we attempt to restore in imagination the physical conditions
of the Pliocene era in Northern Europe, three features stand out
with a certain amount of distinctness: the river Rhine, the basin of
the North Sea, and the gradual refrigeration of climate which from
the earliest times of the Upper Crag seemed to be penne the
approach of the Glacial epoch.

It has often been said that Holland is the ancient delta of the
Rhine, but these borings show that the formation of this delta had
commenced as early as the Diestien epoch. During the whole of the
Pliocene period, and indeed up to the present day, the rivers of
Northern Europe have continued to pour down their sediment,
heaping it up on the gradually subsiding bottom of the North Sea.
The North Sea basin also, bounded in the first instance on the east
by the Miocene deposits of Germany, on the south and west by the
older Tertiary and Cretaceous rocks of Belgium and East Anglia,
had equally come into existence before the deposition of the Coralline
Crag. Since then it has been affected by the great movements of
subsidence and elevation which took place during the Glacial and
post-Glacial periods. As to the changes of level which occurred
during the former, geologists are by no means agreed, but these
must have affected the area in question, while in the posc-Glacial
era the North Sea basin formed at one time a great plain, tenanted
by herds of elephants, whose bones and teeth are still dredged by
Yarmouth fishermen. During the deposition of the Upper Crag

1 Swiss geologists maintain that the glaciation of their country commenced in
Pliocene times, and that milder conditions of climate intervened between it and
the subsequent advance of the ice during the Pleistocene era. See Dr. Preller’s
paper in Quart. Journ. Geol. Soc. vol. li. (1895) p. 369; also Dr. A. Heim,

‘Die Geologie der Umgebung von Ziirich’ (VI. Internat, Geol. Congr. 1894),
p. 181. If this was so, this interglacial period may possibly have coincided
with the deposition of the earlier portion of the Cromer Beds, which, as we
have seen, indicate a climate somewhat milder than that of the Upper Crag.

776 THE PLIOCENE DEPOSITS OF HOLLAND. [Nov. 1896.

this basin was filled by the waters of a shallow sea, the boundaries
of which travelled now and again in a northerly direction. Its
position to-day is similar to that which it occupied during the
Scaldisien period, except that it is connected with the 8.W. by the
Straits of Dover, and that near its western margin have accumu-
lated the Glacial beds of Norfolk and Suffolk, and in its eastern
portion material brought into it by the Rhine and the Scandinavian
ice.

The hypothesis of a permanent basin with shifting shore-lines
seems to be in accordance with all the facts of the case. It affords a
possible explanation of the character and disposition of the various
Crag beds of the East of England, and enables us to arrange them
in order, as members of a continuous and closely-connected series.
‘The western shore of the Newer Pliocene gulf extended at no time
far beyond the present English coast, and hence the shallow-water
beds of Norfolk and Suffolk, originating at no great distance from
the shore, and following from time to time the shifting margin of the
sea, give us information as to the various changes which have there
taken place in the distribution of land and water. The strata
revealed by the Dutch borings, on the contrary, were deposited
farther from land and in a subsiding area, and therefore, while they
throw no light upon tke geographical conditions of the eastern
portion of the basin, they afford a vertical sequence of beds
representing continuously a considerable portion of the Pliocene
epoch. It may be hoped that from this almost unexplored field
most important results may hereafter be gained.

The lines which I have drawn to show the possible distribution
of land and water during the successive stages of the Crag period
must be regarded as only tentative, but even if my suggestions afford
no solid and permanent resting-place, they may at least serve as
stepping-stones to firmer ground, and to a position whence we may
obtain clearer light on some of the problems of the later Tertiary
geology of Hast Anglia.

Lists of the shells obtained from the different Dutch borings,
arranged according to the classification adopted in this paper, are
given, showing the resemblance of the different faunas to those of
the different horizons of the English and Belgian Crags, and the
comparative abundance of the different species in each.’

These lists, which contain the names of all the species at present
known from the Pliocene beds of Holland, are arranged to show at
a glance the much closer resemblance between the Amstelien and
the Upper Crag than to the Scaldisien or the Walton bed. Two
schedules are given: the first containing those species which occur

1 My best thanks are due to Mr. P. F. Kendall, F.G.S., who, with the late
Mr. R. Bell, spent much time and labour in working out the Walton fauna, for
allowing me to supplement my own knowledge of this formation by the
examination of a list of the Walton mollusca which he is preparing for
publication, and also to my good friends in Belgium, Holland, and at
Jermyn Street for their courtesy in placing so willingly at my disposal their
stores of information.

Fauna OF THE PrLioccenE DEposits oF HOLLAND.
N.=Norwich Crag only. A.=Amstelien. a.=Arctic.

Schedule I.

known living. .

Flg|s| 2

Forbes’s ‘ Crag 2 5 BIg oS

HcHINODERMATA. Kehinodermata.’'z, |F lal)
Hehinus Lamarckti, Forbes .........) seesecees fg8 geelione fam
ECOL AB OLDE \cocwaecescocf |” sacescene (GSR Eee eee Hee
Echinocyamus pusillus, Mill. ......8 .se.eeeee eles Hie

Echinocardium cordatum, Penn....) Amphidecus }...|...|...}
. cordatus.

i Busk’s ‘Crag |
| Polyzoa.’

Pouyzoa.

| Salicornaria sinuosa, Hass. ......... Lat Mee seers Loteseleal ce | Se
Hippothoa abstersa, Wooded cre
Membranipora tuberculata, BOSCH Diane ceo
BONUSITA GEUCOOMA, BUSK ...ck.. fs esncenne

Salicornaria crassa, Wood .........) scnacenee oclane lee: ioe
Membranipora trifolium Wood ..4 2. eee. ‘oe ata ee

Mo.uvsca
(Land and Freshwater).

Diastopora meandrina, Wood ...... | Mesenteropora. f...|...|...)...
Entalophora subverticillata, Busk .j Pustulopora. }...|...|...}...| ... f...)...
Hornera frondiculata, Lamour. ...§ — ......... ‘ESE eee) Ga ae [coal

Lepralia innominata, Couch ...... HED Warren Bolas ome I...

| Eschara monilifera, M.-Ed.......! holt (eee BY aes lowe Py

porosa, M.-Ed. ............ iS Baenaenes Pes Pease fe.
Melicerita Charlesworthti, M.-Kd.. —......... Bee ere ae AC
Retepora simplex, Busk ............ ie heer ence Pacdleeelay ‘od bat a) al ae
Cupularia denticulata, Cour. ......J) 00 ......0 Babee. ia pect cen) gee
Cellepora coronopus, Wood ......... Dish dacerreglon bedlaneleaics ooh Hoa ae
pumicosa, eae eee Wk ce ron nlite BS easice, Meee nee ae

Tunulites LORMIEO MUON ace deaaeeesh aw, avconikes socio eee ee

Norwich
Crag

Pisidium amnicum, Mull. .........5

Paludina lenta, Brand ...............
Hydrobia similis, DAD: | eaietvanes xe
Planorbis vortex, Linn. ............

eet} eeleee

Succinea elegans, Riss. ............6+
Zonites cf. cellarius, Mull. .........

sp.
Helix ef. pulchella, Ji Ov0 | nee Ase!
DYGMEA, AAD: wo ..cqsrcvacsea
Pupa muscorum, Mill. ..............-
Clausilia pliocena, WVOOU sisctceges acs

Brachiopoda.

eeleeelee of

eel eeeleee

Pees eee eroeserssesssssseees

eeorleeslees

Per Pes ie >

Argiope cistellula, Wood ............
Terebratula grandis, Blum..........

caput-serpentis, Linn. —..........

serleoeseas

“+++ + | Sealdisien, Holland.

| Scaldisien, Belgium.

| tetti tet ttt: t+

| Walton Crag.

nage + ai | Diestien, Holland.

++:

|

+!

[++t++++++++++++ +

p++tt+++t+++t++4+4+ 4+
| + ++t++4++44+4+4++4+ 4+

| Diestien, Belgium.

+ ++ | Coralline Crag.

ar

+

7

Anomia ephippium, Linn.
Pecten opercularis, Linn. ............
ventilabrum, Goldf. .........
Gerardi, Nyst
Mytilus edulis, Linn.
Nucula Cobboldie, Sow. ............
I@ULGGIG, SOW. <2220---2 0.00
tenuis, Mont.
Pectunculus glycimeris, Linn. ......
Leda lanceolata, Sow. ..............-
myalis, Wood
TUMMUE VOM. F002 00 -ise <0
Lucina borealis, Linn. ...............
arcuata, Mont.

9

39

3?

Cardita orbicularis, Leathes
Cardiwm edule, Linn. ..............-

9

2?

39

99

3)

39

39

99

29

39

99

contracta, Say

MR. F. W. HARMER ON THE

Prrocene Fauna (continued).

Schedule I. (continued).

Mo .uuvsca (Marine).

Pelecypoda.

grenlandicum, Chem. .
decorticatum, Wood

nodosum, Mont

, Holand.

++++ | Diestien, Belgium.
++++ | Ooralline Crag.

Wo00d’s ‘ Crag

| Not known living.
Scaldisien, Holland.

| Northern.
| Southern ;

i = page | Amstelien.
| Walton Orag.

weseetees

ee eoreereences

os oe |
+++: ++++4 | Scaldisien, Belgium.

—

Sapa Pt ei
+ +4444 | Diestien

ar
+
+++

Pe ee i ee

FEEL HE+ETH! +44 | Red Crag,

TH+++ oP +++

Loripes divari-

i
A:
7”
i
;
J
|
:

eertee:

subturgidum, W’Orb. ......

fasciatum, Mont. .........
Astarte Galeotti, Nyst
Cyprina islandica, Linn. ............
TOSEICUP SOW: ci cccsecacreses
VENUS OVAI@ OPEN, ......0.- 50000000
Dosinia lincta, Pult.
Donax vittatus, Da Costa
Tellina Benedenti, Nyst
GULGUOMSOW. —..0.ncensson-
pretenuis, Leathes
Semele alba, Wood
fabalis, Wood
prismatica, Mont
Scrobicularia piperata, Bellardi...
SOlen SUiGUG. WANT. J.....0200e--.-00.
TOLISUS (7USas) \UTs0 iT, Aas See a
Glycimeris angusta, Nyst
TAT ACA THOLE, SOW. oes her innns-
papyracea, Poli
Mactra deaurata, Turt. ............
solida, Linn

i, aaa

+t+++++

+
--
+
+
+
+
+

@oceereescosseces

er oe

1sp.
4
+
+
==
+ |.

eerccscesees

+

eoreeeeos

ee

+++ 24+++¢+4+++ +4+4-

eeeceretocestacs

a ee

@eoceccces

+p +i ttet +tt4:

+
+

ecceestcosecs

Seoseesseroeseccae=

SEHUTOTUMD AMAIA. cc seice canoe:
subtruncata, Mont. .........
Mya arenaria, Linn.
DING EMU MMIC, 0. 222-20. 2220
truncata, Linn.
Saxicava rugosa, Linn.
Corbula gibba, Olivi

t+tt Avett ttt A:

eeceeseescesces

were essccsasseces

eerccocceecces

+++

eer eesceccoresseoes

+ ++4++4

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. 779

Puiocene Fauna (continued).

Schedule II,

Gasteropoda.

| Turritella terebra, Linn. ............
Calyptrea sinensis, Liun............-
Natica Aldert, Forbes ..............-
MIEAETESE,. SOW yw 0-0 0000 clesaseave

3 kelicina, Broc. ...... pe ee

» millepunctata, Lam..,........
Hydrobia ulve, Penn. .............-
Paludestrina terebellata, Nyst......
Litiorina littorea, Linn. ............
Rissoa reticulata, Mont. ............
Chemmitzia densicostata, Phil.......
- elegantissima, Mont....

+ indistincta, Mont.......

2 similis, Wood .........
Cassidaria bicatenata, Sow..........
Buccinum undatum, Linn. .........
INGE FELICOSHASOW. ..-...6000,0000505
Purpura lapillus, Linn. ............
Fusus elegans, Charl. ............+.-
9) BO TOCUIS AWA CIO... 0000200004

5, Comsocialés, Wood. ......-0..-

,, scealariformis, Gould .........
Ringicula ventricosa, Sow. ........-

Pleurotoma clathrata, M. de S. ... as sre Walle
- Bree, MON. edencf weswesses
COnCCH ATG, BPrigetenus<-+008-00s0s0a0e

Pelecypoda.

OStHCG CONS: MUR Gecccitcpechevtssed | scasensae Pa | Bree Be ae Pe
Pecten sumilis, Vaskey .....cc..00c.§ oseeosees peeleseaeeiaaa)) accu [-F'|-+-| =.
», septemradiatus, Mill. ......

Tima subauriculata, Mont. .........) ceseesees cs ae A ae ae aa
Limopsis anomala, Hich. ..........+. .pygmed, |...)...|+}...] ... p-- --

Nucula nucleus, Linn. ............++.
Yoldia semistriata, Wood ......... eo Sa ae ee
CATA CERUISPEIIER “even cae eect eek swcsweses | Mecelycs|EaBeocl sce pMede

» chameformis, Leathes

5) See areamerenies Sees f eacsveca WO TEE] cae

Sal) HSCEI SRE Sse Saw) ec cicabecs )) UBbeate al.
Astarte Basterotit,\de Lia}. ...coce2) secensens

93, (COPRDULOTAEH IOC Daajs scsencecs] | avscenee

Si) RECOUTAS GOW Con .chs.cecsk Y sanaseses

yy) Othalit, ABBA). -.secsecns-:

tt) LUPtANOULTREN MOM: pe-svesss | essences. | fran r. a be cr

Q.J5.G.8. No. 208.

slg] LJ.
2p S|. EE
5 mice Set eo
[ ES) y
Mia) &fors|
E les a | a1g15 q/A} eS
a A ley 1c)
e|/E/ELS Biel 6. Net betl tes
a| S| of BH |'a O|O| -=
as /e1e| S fels| 3 lel 3
Wood's ‘ Crag |2|% =| q gls| i [212] §
’ :
Mollusca’ JA|A Als pial S ISAO

eseeteses jj Fraciseeieor

eoorseeo.

Fi+
+

eoelese

eosscesee BT feeeleee

wecsectse Besaleosleorh f | eos Breriees

eececsesee Breeosieoe| f BT | eee Breet ree

eeoseresse

eov5ccceece 8 8 ET feecleoood ff | “~T Beerticee

=
t+btttt+:

comieaali fuken, | cate: a2 er) | | ees Been tee

2p IE
ae

a

+ ++ ++

++ ++

+ +:

++

ee ceceee

++
i bb ttt

++++: +444

ii t+: ++:
ttt +t¢t¢4+ $4

++: ++:
++:

780 MR, F. W. HARMER ON THE [Nov. 1896,

PLiocENE Fauna (continued).

‘ rig ae 3
sb Ae EE
E ers| . Stal @
: =< mia] S2 Fors) &
Schedule II. (continued). sleet he ia} oO
S|ei/fhe 2 O12 aia} gs
S|oO;/ofS| # Paral 2 fols] -s
| 4/3 /S18/ 0 felis] & [Sls] s
| Wood's ‘Orag }2/ 2 |S #| 3S Tela| @ [3/3] &
Mollusca.” [ala Bla] & IZIel Ee lal s }
Pelecypoda (continued).
Astarte pygme@d, Miinst. .........-.- Lr ei .es|swehecel eee = +)o) 4 7
Woodia digitaria, Linn. ............ eee ee 8 bodies +H...) 2... +i] + ++] +
ft, WCRCUTTENS INV OOU 4.2538 osnie202 :. 2) eee Hyo..f..f.. Ta ee 3 +i}
Diplodonta cf. rotundata, Mont...) .......00 0 ee adeee Se Deal aatee Hy) we Peet. +
Tapes pullasind, Mont.......5.0..:+«- ta een wfeePice} cee PPT Ee TE i
Tellina compressa, Broc. .......+++- Te eee | Eee +h...) oP PET... PEPE
Psammobia ferroensis, Chem. ....--f ss... a eee ae ie EE eee ae
ss vespertina, Chem....... Lik Sonam aie ip 5 eee 26 aa
Thracia pubescens, Pult. .........+-- he eee alae at | et es AS
Scaphopoda.
Dentahumclk denials, Linn. .cc.:3 ~ seadeewoe Ase lees a lel Bb LEE] +
3 CHEQIES, AMINO), cece. sche jhe Been cae pi Natal |v oe SUE) te
Gasteropoda.
Emarginula fissura, Linn. ....02.-- .sseceses mals >| 6) eee
Trochus cineroides, Wood ......... ee eae 4) al Aas) eee By ire
» ef. 2tzyphinus, Linn. ...... We Uepteersss 7. SW Hoeeh eh aee ) ee Eee
Scalaria clathratula, Adams ......f ....c.00e lea | PS ol
Turritella inerassata, SOW. ....c0c0f — seceeneee ew cla a | ee a) eee
PPR REP RUES MAS Ce boc csisisle staionnias T. triplicata, |...|... AL le ee ee Me) ee ae
Broce.
Vermetus intortus, Lam. ............ dt eeeeteere, bebe Ale er ea |
Capulus ungaricus, Linn. ......... i Fe aa Bea ie als ee ee ee
: recurvatus, Wood ......... af cavities We Peri ion bositecs:| alls. + J+i...| +
Natica hemiclausa, Sow. ...,...0cc0) ss seeneee = |e ee |e
s5 | VSOWETUYEL, ON YBL.... 2+. 0000r00- N. catenoides, }+}...)...]... AE] + THY... +
Wood.
Rissoa cf. semicostata, Woodw. ...4 R. curticostata, }...\... Pie, Ham alt ae aie ee
Wood.

», eetlandica, Mont. ............ a @ Soe eet ABI BBoI re © (Peele + J+...) +
Aporrhais pes-pelecant, Linn. ...... foc h akemeees. aa calle ~ fle) be PEI+] +
Buccinum Dalet, Sow. .........0.+0+- is MRRP oe Pei bee ce eee te
Nassa elegans, Leathes ............... fe keene BOs aes Gk! Wi felt] T+
Purpura tetragona, Sow. .........4.. ee Seat BE) || eel os ee eee
Fusus alveolatus, Sow. ........-.0+00- 1 (Zrophon)” F+1..4.1....0... [4 |42) 4 eee

§) | GNUGUUS MAND. 2... 6. 0nen a - volet | cdlceal ee dee See

F | COMUTATUUS UUTAM: ~".. 0 -esenee Di a | ene 2 Sere HSS) 5
Pleurotoma cancellata, Sow. ...0-4 cece eceee wefesefers] oes Qf-|os|) see meta one ete

a Coston Da 'Costa’...s.si) | .ccccoske Aca -gtitl + P.. Be
Ringicula buccinea, Sow. .........++- ie gemeecte sear Paes | 3h, ae ee sell - T4EI+] +
Bulla umbilicata, Mont. ............ B. conuloidea, }...|... oe ee pee | eyes,

Wood.

Vol. 52.] PLIOCENE DEPOSITS OF HOLLAND. 781

in the Amstelien, the presence of any of them in the lower beds
being also marked; and the second, those which are confined to the
latter. The more abundant forms are indicated by thicker crosses ;
those which seem to distinguish the Amstelien are indicated by the
letter A. It will be seen that most of these are abundant, and
are also common in the Upper Crag, while they are either absent
from the Walton bed, or are rarely found in it.

Synoptical Table of the Pliocene Strata.
ENGLAND. BrLcium. HOLLAND.

Cromer Beds.
(Forest Bed Series).

Weybourn & Bure
Valley Crag.

Chillesford Clay.
Norwich Crag.

Red Orag. Amstelien.

Walton Orag:

Upper bed. Poederlien. Scaldisien.
Lower bed. Scaldisien.

Coralline Crag. Zone a Lsocardia Cor. Diesti
Lenham Crag. Diestien Sands. Reon

EXPLANATION OF PLATES XXXIV. & XXXV.
Puate XXXIV.

Map to illustrate the possible distribution of land and water in the Anglo-
Dutch Area during the various stages of the Pliocene Period.

Puate XXXY.
Map of the Orag District, on the scale of 4 miles to the inch.

Discussion.

Mr. Crement Rep agreed that the dominant factor in Newer
Pliocene geography was the folding which raised an east-and-west
barrier across the South of England and Belgium, gradually forced
northward the Pliocene sea and the estuary of the Rhine, and
caused the accumulation in Holland of an enormous thickness of
shallow-water deposits. He suggested that the ‘Amstelien’ may
fill the gap between our Walton and Butley Crags, for the fauna is
scarcely as Arctic as that of the Butley Crag. The evidence seems,
however, hardly sufficient to settle this point.

782 THE PLIOCENE DEPOSITS OF HOLLAND. [Nov. 1896.

Mr. H. B. Woopwarp referred to the excellent geological map of
Norfolk made by Mr. Harmer before the official Geological Survey
was commenced, and remarked that the Chillesford Clay had been
one of the chief sources of dispute. While working in the Norwich
area he had found no persistent divisions in the group which
included the Fluvio-marine Crag, the Chillesford shell-bed, the
Chillesford Clay, and the Bure Valley Beds, and he had grouped
them under the general term Norwich Crag Series. He was there-
fore glad that Mr. Harmer now agreed that the beds belonged to
one formation ; and if it were desirable to use a term that should
correspond with the other group-names used by the Author, he
would suggest that the old term ‘ Icenian’ be used for this Norwich
Crag Series. He was disposed to agree with Mr. Harmer’s general
conclusions with regard to the Chillesford Clay, and thought that
now there were no serious differences of opinion between them ; the
Author in fact had done much to harmonize a subject which before
was full of discord.

Mr. W. J. Lewis Aszorrt said that he had long since come to the
conclusion that we must know considerably more about Tertiary
Holland and Belgium before we can know the correct history of the
Weald. His closer studies of the latter had suggested hypothetical
conditions in these countries, which this valuable paper would show
to actually exist. The Lenham Beds might be shown to extend a little
south of the position indicated on the map, and very much farther
west. About Lenham the casts of fossils in the ironstone are not rare,
but they quickly decrease as we travel westward. We note, however,
the incoming of flint-pebbles in a soft white condition. By the help
of these ironstones and the gradually altering nature of the sands we
can trace the Lenham Beds into Surrey. It was the southerly
elevation and north-easterly depression that subsequently raised the
Lenham sea-bed to hillsides, and it was the rivers which flowed
down these in later Crag times that deposited the Piateau-gravels
in which are found the first evidences of artificially-worked flints.

The AvurHor replied, thanking the Fellows for the reception
accorded to his paper.

oy

~ Quart.Journ Geol. Soc. Vol. LIT. PL XXXLY.

CC

Fa?

SCANDINAVIAN
DRIFT

Pe

DRENTHE

MIOCENE

ee

° “MIOCENE
Creen/o

= \
Saxmur ats “]
-Chillesfortye #

-Orfe

No G
RWICH CRAY -_

Aaa ence aeeee~

Sudbury

=
nd

5 Ss
MIOCENE
ro ;

Sy »

CROMER BEDS
WEYBOURN & BURE VALLEY CRAG
; & PEBBLY SERIES
CHILLESFORD CLAY
NORWICH CRAG

RED CRAG & AMSTELIEN

WALTON CRAG, POEDERLIEN & SCALDISIEN

BRORRES

CORALLINE CRAG & DIESTIEN

MAP to illustrate the possible DISTRIBUTION of LAND & WATER in the ANGLO-DUTCH

area, ouring the various stages of the PLIOCENE period.

FW HARMER Del.

a

Quart. Journ.Geol. Soc. Vol. LIT. PL XXXV.

THE
{CRAG DISTRICT,
deposited,

REFERENCE TO THE MAP.
=i a and Upland and Lowland Brickearths (Post Glacial).
‘ a Boulder Clay. (Upper Glacial.)

(Middle Glacial. )

.'». (Lower Glacial. )

a

“zh aa eds (Forest Bed Series.)
‘nd and Pebble Beds, and Weybourn and Bure Valley Crag.
—————
Clay.
frag. (MM 4 The Red Crag. 4 The Norwich Crag.

(Newer Pliocene)

(Older Pliocene.)

fo

ays. © Well Borings.
muraes of Section A to W. (See ‘‘ Supplement to Crag Mollusca.”’)
ids.

of the principal Parish Church of the places named. The position
h is thus shown, but in some few places where the shading is intricate
mitted.

| Quart Journ Geol, Soc Vol Lil PI XXXV

| THE
ot thet oe ean on th freon CRAG DISTRICT,
botWeen Waybourn and Hasbro
wf 5 Showing all the UPPER TERTIARY formations

4S.
Cas
\\

irre
YN

and, hypothetitally, the geographical conditions of the various
stages of the Newer Pliocene period in Bast Anglia.

Reduced from a portion of a Geological Survey Map
made during the years 1864 to 1872,

By Searles Vs Wood, Junr., F.0.S., and E. W. Harmer, F.G.S.

Seale 4 Miles to the Inch,
Chillesford Clay HS

reached In boring at |
ae ea From the Supplement to

NN the Monograph on the Crag Mollusca
Palmontographical Society,
1872,

Clay shown In cliff ecction between
Pakefleld and Keasingtand.

The strong coloured lines are intended

fo represent the possible limits within
which the various beds were originally

lepasited

REFERENCE TO THE MAP.

E2311 Valley Gravel hnd Upland and Lowland Brickearths (Post Glacial).

E210 Plateau Gravel,

GES 9 The Great ¢ hilky Boulder Clay. (Upper Glacial.)
E23] 8 Sand and Grates } (Middle Glacial.)
C25 7 The Contorted Dat. * (Lower Glacial.)

WB 6 The Cromer
BB 6 The Pebhty Sai
BT 5 Vhe ChillesforfClay.

3 4 The Walton Gy, MG The Rea Crag, MI 4 The Norwich Crag,

BS 3 The Combine Frag {Older Pliocene.)
E55 2 The London
WB 1 The Chak
Ratings © Wei Borings.

so ----------- Lins of Section AtoW, (See ‘Supplement to Cmg Mollusea,”)

Gp Bros.

Denotes the positin of the principal Parish Church of the places named. _ The position
of every Parish Churth ix thus shown, but in some few places where the shading is intricate
the nomes have been qnitted.

TWDenotes a Hamlet.

(Forest Bed Series.)

and Pebble Beds, and Weybourn and Bure Valley Crag. | %
(Newer Pliocene)

GENERAL INDEX

TO

THE QUARTERLY JOURNAL

AND

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

[The Fossils of which the names are printed in italics are figured]

Aalenian strata at Dundry, 708.

Absaroka Range (U.S.A.), volcanic
rocks of, 610.

Ach na Hannait (Skye) section, 350;
do. in cliff N. of, 375.

Acidaspis, British Silurian species of,
235-245 & pls. vii. & viii. ; A. Bar-
randei, 241 & pl. viii.; A. Brighti,
236 & pl. vii.; A. callipareos, 243 ;
A, convera, sp. nov., 425 & pl. xxi. ;
A, coronata, 237 & pl. vii.; A. cre-
nata, 239 & pl. vii.; A. deflexa, sp.
nov., 239 & pl. vii.; A. erinaceus,
243; A. Hughesi, 242 & pl. viii. ;
A. quinquespinosa, 240 & pl. viii. ;
A. sp., 426.

Acre House Mine
section descr., 203.

Aden, seismic phenomena at, 666.

Africa, seismic phenomena in, 662 &
pl. xxxii.

Agnotus cf. Galba, 408.

Albien strata near Cape La Héve, 117.

Albishorn (Switzerland), glacial de-
posits of, 568.

Allen, Hill of (Kildare), igneous rocks
of, 600, 603.

Allenton (Derby), sections at & near,
498, 502; map of neighbourhood,
facg. 502.

Alman Islet (Canna), columnar basalt
invading agglomerate, 353.

Alpine nickel-bearing serpentine with
fulgurites, 452.

Altschloss (Switzerland), glacial de-
posits of, w. section, 569.

Q.J.G.8. No. 208,

(Lincolnshire),

Alvaston (Derby), interglacial river-
gravels, 503, fig.

Ammonites complanatus, 155; A,
euomphalus, 155; A. Goupilianus,
155; A. laticlavius, 155; A. obtec-
tus, 106; A. Renevieri, 156; A.
(Acanthoceras) hippocastanum, var.
compressus, nov., 1O7 & pl. v.; A.
(Ac.) pentagonus, sp. nov., 156 &

hiv

Amphipoda, known fossil, xcii.

Ampyx binodulosus, sp. nov., 409 &
ple xxi

Amstelien, new zone proposed, 763 ;
mollusca, list of, 765.

Amsterdam (Holland),
Cassel, 761.

An Ceannaich (Skye), section, 341.

Andesite-tuff of Grange Hill, 597 &
pl. xxviil.

Andrews, OC. W., Lyell Fund Award
to, xlviii.; on the Structure of the
Plesiosaurian Skull, 246-252 figs,
& pl. ix.

Angle Tarn (Patterdale), origin of, 15.

Anglesey, geology of eastern corner
of, 618-631 figs.

Annual General Meeting, viii.

Anthrapalemon, structure of, xix.

Antwerp (Belgium), Newer Pliocene
of, 754.

Aporrhais (Lispodesthes) Mantelli,
93; A. sp. (Chalk Rock), 93.

Aptian, correlation of strata between
Kimeridgian and, 542-554 &
pl. xxvil.

section to

3H

784

Aptien strata near Cape La Heve, 116.
Aquilonian stage in Russia, 546.
Arca ligeriensis, 153.

Archean (?) boulders from Kolguev
Island, 58.

Arctic Europe and its Islands, glacial
geology of, Part I.,52-63; Part II.,
721-747 figs.

Arenig Beds near Caermarthen, 525 ;
compared w. do. elsewhere, 532.
Armadale (Sutherland), geology of

country between Kirktomy and, 6386;
do. between Portskerry and, 639 ;
veins of granite and pegmatite in

hornblende-schist, 647 fig.

Arnold-Bemrose, H. H., Discovery of
Mammalian Remains in the old
River-gravels of the Derwent near
Derby, Part I., 497-500 figs.

Arrhets, Mont des (Savoy), 6 ef segq.

Assam, seismic phenomena in, 696,
657 fig.

Assuan (Egypt), sketch of junction of
granite and Nubian Sandstone nr.,,
311; old river-channels at, 316.

Astacidea, known fossil, cv.

Astacoides armatus, unique spinose
ornamentation of, cvi.

Aston, E., & Bonney, T. G., on an
Alpine Nickel-bearing serpentine,
with Fulgurites, 452- 459, w. chem.
anal.

Au (Switzerland), glacial deposits of,
w. section, 567.

Aucella Keyserlingi, 550 & pl. xxvii. ;
A. terebratuloides, 550 ; A. volgensis,
549 & pl. xxvii.; A. v., var. radio-
lata, 550 & pl. xxvii.

Auditors elected, v.

Augite in altered granophyres, 324 &
pl. xiii.

Augite-andesite of Grange Hill, 597
& pl. xxvisi.; of Hill of Allen, 601
& pl. xxviii.

Australia, Permo-Carboniferous Gla-
cial Beds in, 289-301 & pl. xii.;
seismic phenomena in, 661, 662 figs.

Avellana, sp., cf. Humboldti, 93 &

pl. iv.
Avicula, sp., 269 & pl. xi.

Babington, C C., obituary of, lxx.

Bacchus Marsh (Victoria), Permo-
Carboniferous Glacial Beds at, 296 ;
fig. of glaciated boulder from, 297 ;
sections, pl. xil.

Baculites bohemicus, 76 & pl. ii.

Baden (Switzerland), glacial deposits
pr., 560 (w. map).

Bagshot Beds (Lower) in Dorset, 491.

GENERAL INDEX,

[Nov. 1896,

Bajocian strata at Dundry, 708;
Bajocian denudation zbid., 711.

Bala Beds near Caermarthen, 531;
compared w. do. elsewhere, 534.

Bala rocks of Conway district, 276.

Balance-sheet for 1895, xxxiv-xxxviii.

Ball, Valentine, obituary of, lxii.

io Hole (Dorset), section deser.,

Banded structure of rocks near Mul-
lion Cove, 20 e¢ segg.; of rocks in
Kynance Cove, 39.

Banding in Tertiary lavas, 334.

Bangor Group in Anglesey, 623.

Barlow-Jameson Fund Award to J.
Wright, xlix.; to J. Storrie, 1;
list of recipients, xxxi.

Barns Batch (Dundry), section deser.,
689; table of sections from, to
Dundry Church, 696.

Baron Hill (Anglesey), sections at,

_ 624, 625.

Baron Hill Group, 623.

Barry (Glamorganshire), submerged
land-surfaces at, 474-489 w. map
and section.

Basalt, porphyritic, of Hill of Allen,
601 & pl. xxviii.

Basalt-plateaux, Tertiary, of North-
western Europe, 331-405 figs. &
pls. xv.—xix.

Basic eruptive rocks of Brent Tor,
alteration of, 66.

Bathonian strata at Dundry, 709.

Beer Head (Devon) vert. section, 112
& facg. 114.

Belemniies fusiformis, at Speeton,
187 ; lateralis-beds, age of, 213.
Belemnites subquadratus from Kol-

guev, 61.

Belgium, correlation of Crag-beds of,
an of England & Holland,
749.

Bermuda Islands, seismical map of,
668.

Berry Down (North Devon), Morte
Series at, 264.

Bigsby Medallists, list of, xxxi.

Biotite-schists in Eastern Sutherland,
636, 639, 642.

Bittadon (North Devon), exposures
ae Morthoe, Woolacombe, and,

57.

Black, Clyde H., appointed Assistant »
Clerk, i.

Blue Ironshot-beds at Dundry, 706.

Bolvana, Mount (Kolguev), 53, 54.

Bonney, T. G., the Serpentine, Gneis-
soid, and Hornblende Rocks of the
Lizard District, 17-49 figs. & pl. i.
(micruscope-sections); Report on

Vol. 52.]

the Erratic Boulders from the
Kolguev Beds, 58-63; Report on
Specimenscoll. by Col. H.W. Feilden
in Arctic Norway, etc., 741-746 ;
portrait of, presented, exxiil.; and
H. Aston, on an Alpine nickel-
bearing Serpentine, with Fulgurites,
452-459 w. chem. anal.

Boulders and ice-worn stones from
Kolguev Island, 58-63; glaciated,
from Bacchus Marsh, 297 fig.

Boulder Clay, transported, 302-306
figs.; B. C. in neighbourhood of
Derby, 505; of Kolguev Island, 56,
57 ; in North-eastern Anglesey, 630.

Boulder-covered areas in the Kola
Peninsula, 726 et seqq. figs.

Brachiopoda, Cenomanian, 146.

Brachyura, known fossil, eviil.

Brent Tor (Devon), alteration of basic
eruptive rocks, 66.

British Columbia, seismicity of, 665 fig.

British Empire, seismic phenomena
in, 651-668 figs., & pls. xxx.—xxxill.

British Guiana, seismic phenomena
in, 668 fig.

Broadford (Skye), compound dyke,
393-394 fig.

Brown, F. E., obituary of, lxxxii.

Browne, Ven. Robert W., obituary of,
xxx.

Brunval (Normandy), study of cliffs
betw. Cape La Heéve and, 119; vert.
sect. facg. 124.

Bryn Poeth (Anglesey), section in
quarry, 627; felspar-tuff below
pisolitic ironstone at. 627, fig.

Bryn-rhug (Dolgelly), lava of, 514.

Bryn-y-gwin Woods (Dolgelly), dia-
base, slates, etc. of, 515.

Buckman, 8. S., and EH. Wilson, on
Dundry Hill: its Upper Portion or
the Beds marked as Inferior Oolite
(g 5) in the maps of the Geological
Survey, 669-720 w. tables, section,
& map.

Bull Point (North Devon), Morte
Series at, 261.

Bunbury, Sir E. H., obituary of,
lviil.

Burdale (Yorks), Speeton Beds nr.,
188.

Bure Valley Beds, their origin, etc.,
172.

‘Butchers’ Arms’ (Dundry), section
deser., 630.

Butley Crag, list of mollusca, 757.

Cadgwith Cove (Cornwall), granulitic
rocks of, 25, 24.

GENERAL INDEX,

Caermarthen, geology of neighbour-
hood of, 523-541 & pls. xxv.—xxvi.

Calais Newbold, 229-234 & pl. vi.

Calappide, structure of, cxi.

Callianassa, structure of, cvii; C.
Whiteavesii, sp. nov., 223.

Calvados, correlation of Cenomanian
w. that of Orne and Sarthe, 126 ;
minute structure of Cenomanian in,
141.

Calymene Blumenbachi, var. Caractaci,
411.

Camas Tharbernish (Canna), basalts
at, 334 fig.

Canada, seismic phenomena in, 663,
664 (map).

Cancridz, known fossil, exiii—cxiv.

Candona candida, 485 ; C. lactea, 486 ;
C. pubescens, 485; C. subzequalis,
485.

Canna (Hebrides), volcanic neck of,
301 & pl. xvi.; columnar basalts of,
352, 303 figs.; old Tertiary river
in, 3804 e¢ segg.; Tertiary lava
cutting out conglomerate and
shale, 361 fig.

Capstone Point (North Devon), section
to West Down, 263.

Carboniferous (Lower), Eunicites
heidig, sp. nov., from, 448 &
pl. xxii.

Carboniferous Limestone, Pal@acis
humilis from, 440 & pl. xxiii.

Carboniferous rocks of Mont Jovet,
5; fossils (derived) from Kolguev,
60, 61; Carb. in Anglesey, 628.

Careg Onen (Anglesey), sections at,
619; view of cliff at, 621.

Careg Onen Slates, 618.

Carstone in Lincolnshire, 211.

Carter, James, obituary of, xxi.

Carter, Richard, obituary of, lxxv.

Cassel (Flanders), section to Aister-
dam, 761.

Castillo, A. del, obituary of, lxxvi.

Castle Farm (Dundry), section deser.,
676.

Cataracts (Nile), old terraces above
First and Second, 315.

Catometopa, structure of, and known
fossil, exy.

Cavernous Nagelfluh, characteristics
and origin of, 557.

Cenomanian, delimitation of, 99-177
w. sections, lists of fossils, & pl. v.
(fossils).

Cephalopoda of the Chalk Rock, 73;
Cenomanian, 155; of Speeton
Series, table facg. 184.

Ceriocava ramulosa, 145.

Cerithium cuckhamsliense, sp. nov., 92

oH 2

786

& pl. iv.; C. Saunders, sp. nov., 92
& pl. iv.

Chair of Kildare, sedimentary rocks
of, 589.

Chalk, phosphatic, at Lewes, 463.

Chalk, Middle, minute structure of,
in Dorset, 138.

Chalk Rock, mollusca of, 68-98 & pls.
il.-iv.

Chalky Boulder Clay, patches in red
clay, 305 fig.

Chance, EH. J., obituary of, lxxxii.

Channel Islands, seismic phenomena
in, 665.

Chapman, F., on the Foraminifera
and Ostracoda in phosphatic Chalk
from Lewes, 470-472; on the
Microzoa in Marl and Silts from
Barry Dock, 485.

Chatham Island, seismical map of, 668.

Cheirurus bimucronatus, 417; Ch.
eancrurus, 417 ; Ch. keisleyensis, sp.
nov., 417 & pl. xx.; Ch. ef. clavi-
frons, 420; Ch. cf. glaber, 420 ; Ch.
(Pseudosrherexochus) conformis,
420 ; Ch.(P.) subquadratus, sp. nov.,
421 & pl. xx.

Chillesford Clay, its origin, ete. dis-
cussed, 768.

China, earthquake-shocks in, 666.

Chloritic Marl of Cape La Heve, 138.

Cipolin Group in Hastern Sutherland,
638.

Claxby Ironstone, 200.
Clements’ Yard (Dundry),
deser., 679.

Cline, G. W., obituary of, Ixxxii.

Cockfield (Suffolk), patches of Chalky
Boulder Clay in red clay, 305 fig.

Codiopsis doma, 143.

Collins Point (Isle of Wight), section
descr., 105.

Columnar basalts of the Faerde Is-
lands, etc., 384; of Canna, 352, 353
figs.; col. pitchstone of Hysgeir,
371

section

Compass Hill (Canna), section of cliffs
below, 335.

Coniston Grits and Flags, (?) equiva-
lent in Kildare, 596.

Coniston Limestone Series equivalent
in Kildare, 596.

Conway (North Wales), Llandovery &
associated rocks of, 273-288, w.
map & sections.

Cooke, J. H., Contributions to the
Stratigraphy and Palzontology of
the Globigerina-limestones of the
Maltese Islands [abs.], 461.

Copland-Crawford, R. F., obituary of,
Lyi

GENERAL INDEX.

[Nov. 1896,

Corbis rotundata, 153.

Coroghon Mor (Canna), columnar
eae invading agglomerate, 353

g.

Cotteswold area, correlation of strata
w. those of Dundry Hill, 704 &
table vi.

Council, Report for 1895, viii.; and
Officers elected, xxiii, xxiv.

Courtonne du Murdrac (Normandy),
section nr., deser., 128.

Crag-beds, correlation of English,
Dutch, and Belgian, 749.

Craie de Rouen nr. Vimoutiers, Mor-
tagne, etc., 131 et seqq.

Crandall volcano (Montana), gabbro,
ete. of, 612.

Crangonidea, structure of, & known
fossil, ec.

Crepidula, sp. (Chalk Rock), 90.

Cretaceous podophthalmata from

‘ Vancouver & Queen Charlotte
Islands, 221-228 figs.; of Lebanon,
Calais Newboldi from, 229-234 &
pl. vi.

Crioceras ellipticum, 84 & pl. iii.

Cromer Beds, 772, 774.

Crosfield, Margaret C., & Ethel G.
Skeat, on the Geology of the Neigh-
bourhood of Caermarthen, 523-541
& pls. xxv.—xxvi.

Crustacea, life-history of, in Later
Paleozoic and in Neozoic times,
xci—cxvili ; podophthalmatous, from
Cretaceous of Vancouver & Queen
Charlotte Islands, 221-228 figs,

Crystalline schists in relation to foliated
granites of Eastern Sutherland, 633
-648 figs.

Cuil nam Marbh (Canna), section,
362.

Cumacea, known fossil, xev.

Cyclometopa, structure of, exiii.

Cyphaspis (?) Harknessi, sp. nov., 435
& pl. xxi.; C. (Lornquistia, subgen.
nov.) Nicholsoni, sp. noy., 483 &
joes oat.

Cyphoniscus socialis, 410.

Cyprus, seismic phenomena in, 666
Ww. map.

Cythere pellucida, 486.

Cytheridea torosa, var. teres, 485,
486.

Cytherura producta, 487.

Dana, J. D., obituary of, lix.

Darwinula Stevensoni, 486.

David, T. W. Edgeworth, Evidences
of Glacial Action in Australia in
Permo-Carboniferous time, 289-——
301 & pl. xii. (sections).

Vol. 52.]

Dawson, Sir William, exhibits &
comments on specimens of Hozoon
canadense, CXXVil.

Deckenschotter, Subalpine, character-
istics and origin of, 557.

Deeley, R. M., Discovery of Mam-
malian Remains in the old River-
gravels of the Derwent near Derby,
Part IT., 501-509 figs.

Defrancia (Pelagia) Hudesii, 146.

Denbighshire Grits and Flags, at
Conway, 284; correlated with those
of other areas, 287.

? Dendrophrya erecta, 487.

Dentalium turoniense, sp. nov., 96 &
pl. iv.

Denudation, effects of, in Tertiary
Volcanic series of North-western
Europe, 402.

Derby, Mammalian remains in old
river-gravels near, 497.

Derbyshire, gypsum-deposits of, 461.

Derwas fault (Dolgelly), slates, etc.
west of, 516.

Derweat River, discovery of mamma-
lian remains in old gravels of, 497-
509 figs.

Devon, Cenomanian succession in, 110;
minute structure of Cenom. beds of,
136; list of Cenom. fossils from,
158 ; (North), Morte Slates, etc. in,
254-270 figs. & pls. x.—xi. (fossils).

Devonian fossils (derived) from Kol-
guev, 60, 61.

Diabases, intrusive, in neighbourhood
of Dolgelly, 517.

Dicranograptus-shales near Caermar-
then, 530; compared w. do. else-
where, 534.

Didymograptus _bifidus-beds _ near
Caermarthen, 527; compared w.
do. elsewhere, 533.

Didymograptus Murchisoni - shales
near Caermarthen, 529; compared
w. do. elsewhere, 534.

Diestien in Belgium, 754; mollusca,
list of, 764.

Differentiation, magmatic, extrusive &
intrusive igneous rocks as products
of, 606-617 & pl. xxix. (map).

Discorbina obtusa, 488; D. rosacea,
488.

Dolgelly (Merionethshire), Lingula-
Flags and igneous rocks of neigh-
bourhood, 511-522 figs. & pl. xxiv.

pea).

Donnington (Lincolnshire), Claxby
Ironstone, etc. ur., 201 é seg.

Dorippide, structure of, CXi.

Dorset, Cenomanian succession in,
107 ; Eocene deposits of, 490-495.

GENERAL INDEX.

787

Dorset-Somerset area, correlation of
strata w. those of Dundry Hill,
704 & table vi.

Drewton (Yorks.), section deser., 190.

Drifts in North-eastern Anglesey,
630.

Dromiacea, known fossil, ex.

Duke, Rev. E., obituary of, Ixxvi.

Dumortieria-beds of Dundry, 707.

Dun Mor (Sanday), view of, pl. xvii.

Dun Beag (Sanday), sections, 367,
368 ; views of, pls. xviii. & xix.

Dundry Hill: its Upper Portion, or
the Beds marked as Inferior Oolite
(g 5) in the Maps of the Geological
Survey, 669-720 w. tables, section,
& map (p. 715).

Dunmurry Hill (Kildare), sedimentary
rocks of, 595.

Dykes, in Lizard district, 42; Ter-
tiary, in North-western Europe,
382; in North-eastern Anglesey,
629.*

Harthquake-catalogue, formation of,
651.

Hast Anglia, geol. map of, pl. xxxv.

East Keal (Lincolnshire), section nr.
deser., 204.

Eastbourne (Sussex) vert. section facg.,

Echinodermata, Cenomanian, 143.

Hichthal (Switzerland), section at,
562. .

Electric Peak (Yellowstone Pk.), rela-
tion of igneous rocks to other
eruptions in the region, 609.

Elles, G. L., and E. M. R. Wood
on the Llandovery and Associated
Rocks of Conway (North Wales),
273-288 with map & sections.

Emarginula aff. divisiensis, 85; E.
Sancte-Catharine, 85; EH. sp.
(Chalk Rock), 85.

England, seismic phenomena in, 655,
656 w. maps.

Enys Head (Cornwall), serpentine &
granulite at, 30 figs.

Kocene deposits of Dorset, 490-495.

Kozoon canadense, specimens exhibited,
et¢., CXXvVii.

Epidosite (?) nr. Porthoustock Cove,
42.

Epidote, its occurrence in Loch Sea-
vaig rocks, 386.

Erratics from Kolguev Island, report
on, 58-63; in the Kola Peninsula,
726 et seqgq. figs.

Eryontidz, structure of, & known
fossil, ci.

758

Estimates for 1896, xxxii-xxxiii.
Ktzel (Switzerland), molasse-depres-

sion & moraine-wall betw. Hohe™

Rhonen and, 572 fig.

Eunicites Reidie, sp. nov., 448 & pl.
ex,

Europe (North-western), Tertiary
basalt-plateaux of, 331-405 figs. &
pls. xv.—xix.

Evans, Sir John, receives Wollaston
Medal for Ed. Suess, xl; presents
portrait of Huxley, exxv.

‘Byes’ in hornblende-schist. in Porth-
oustock Cove, 19, 20 figs.

Farshit (Egypt), section at, 313.

Faults in the Nile Valley, 310; in
Tertiary basalt-plateaux of North-
western Europe, 399.

Feilden. H. W., Notes on the Glacial
Geology of Arctic Europe and its
Islands. Part I.: Kolguev Island,
2-58 ; Part II.: Arctic Norway,
Russian Lapland, Novaya Zemlya,

- and Spitsbergen, 721-747 figs.

Fellows elected, i, ii, lll, v, vil, exix,
CXX, CXXi, CXXii, Cxxill, CxKV; names
read out, CXxV, CXXVil.

Financial Report, xxxil.

Fissure-eruptions, ancient, in Yeillow-
stone Park region, 613.

Fitch, Robert, obituary of, lix.

Flint-implements from Barry Dock,
479.

Foraminifera in Lewes phosphatic
chalk, 470; at Barry Dock, 487.
Foreign Correspondents elected, exxil.

Foreign Member elected, exxii.

Forest, submerged, at Barry Dock,
480, 482.

Forest Bed Series, so-called, 773.

Franz Josef Land,raised beaches in,738.

Freestone (Oolitic) at Dundry, geo-
graphical extent of, 711.

Frodbonyp (Suder6), section, 340.

Fulgurites from the Riffelhorn and
Hornli, 452, 456 w. chem. anal.

Gabbros in and near Porthoustock
Cove, 42, 43 fig.; intrusive, in
Tertiary volcanic series of North-
western Europe, 384.

Gabbro-fragments, incorporation of,

modifying granophyres of Strath

(Skye), 820-330.
Gacé (Orne), section descr., 132.
Gaize (=Upper Greensand) at Cape
La Héve. 117; minute structure of
same, 138.

GENERAL INDEX.

[Nov. 1896,

Gallatin Mountains (U.S.A.), intru-
sive rocks in, 611.

Gardiner, C. I, and 8. H. Reynolds,
on the Kildare Inlier, 587-605 figs.
& pl. xxviii.

Gasteropoda of the Chalk Rock, 85.

Gault, equivalent of, near Cape La
Heve, 117.

Gebel Ain (Egypt), sketch at, 310.

Geikie, Sir Archibald, the Tertiary
Basalt-plateaux of North-western
Europe, 331-405 figs. & pls. xv.—
LK,

‘ Geocratic’ movements, 552, 553.

‘Geological Magazine,’ prosperity of,
lxxxvil.

Geological Survey, progress of, in
1895, lxxxiv; G. 8. map of Dundry
Hill discussed, 718.

Gibraltar, seismic phenomena at, 665.

Gilfachwydd (Dolgelly), slates, ete. of,
514.

Girgeh (Egypt), river-terraces at, 313.

Glacial deposits in Subalpine Switzer-
Jand, 560 ; geology of Arctic Europe
and its Islands, Part I., 58-63;
Part II., 721-747 figs.; Permo-
Carboniferous Beds in Australia,
289-301 & pl. xii.

Glaciation in Anglesey, 629.

Globigerina-limestones of the Maltese
Islands, 461.

Glypheide, structure of, & known
fossil, ev.

Gneisses in relation to granites in
Eastern Sutherland, 633-648 figs.
Goes (South Beveland), boring at, 760.

Goniophorus. sp., 143.

Gooseland (Novaya Zemlya), general
view of, 733 fig.; rock-specimens
from, 746.

Gorkum (Holland), boring at, 760.

Gorleston (Suffolk), transported Boul-
der Clay near, 302.

Gosina River (Kolguev Island), ter-
races across mouth of, 725 fig.

Grange Clare Hill (Kildare), sedi-
mentary rocks of, 595.

Grange Hill (Kildare), sedimentary
rocks of, 589; igneous rocks of,
596, 603.

Granites, junction with Nubian Sand-
stone at Assuan, 311 fig.; foliated,
and their relations to the Crystal-
line Schists in Eastern Sutherland,
633-648 figs.

Granophyres, altered, of Strath (Skye),
320-330 with map and pls. xili—
xiv. (microscope-sections); intrusive,
in Tertiary voleanic series of North-
western Europe, 389.

Vol. 52.]

Granular gneiss in Eastern Sutherland,
636, 639.

Granulitic group of Lizard district,
genesis of, 22; relations of same
to serpentine ibid., 26 figs.

Gravels of Derwent River, mammalian
remains in, 497-509 figs.

Green Harbour (Spitsbergen), dia-
grammatic section at head of,
739.

‘Green schists’ of S. coast of Lizard,

46.
Greenlo (Holland), section to Norwich,
53

Greenly, Edward, on the Geology of
the Eastern Corner of Anglesey,
618-631 figs.; and J. Horne, on

_ Foliated Granites and their Relations
to the Crystalline Schists in Eastern
Sutherland, 633-648 figs.

Greensand (Upper), equivalent of,
near Cape La Heéve, 117; minute
structure of same, 138.

Gregory, J. W., the ‘ Schistes lustrés’
of Mont Jovet (Savoy), 1-11 w.
map.

Gypsum-deposits of Notts & Derby-
shire [abs.], 461.

Halkin Mountain (Flintshire), Huni-
cites Reidie, sp. nov., from, 448 &

ieexuii.

Hallett’s Cove (South Australia),
Glacial Beds at, 294.

_ Hamites sp., from Chalk Rock, 74.

Hard Tarn (Helvellyn), origin of, w.
plan & section, 13.

Harker, Alfred, Wollaston Fund
Award to, xli.; on certain Grano-
phyres, modified by the Incor-
poration of Gabbro-fragments, in
Strath (Skye), 320-330 w. map &
pls. xlii—xiv. (microscope-sections).

Harmer, F. W., on the Pliocene De-
posits of Holland and their Relation
to the English and Belgian Crags,
with a suggestion for the establish-
ment of a New Zone ‘ Amstelien,’
and some Remarks on the Geo-
graphical Conditions of the Pliocene
Epoch in Northern Europe, 748-
781 w. tables of fossils & pls. xxxiv.—
XXxv (maps).

Harpes costatus, 436; H. Wegelini,
436; H. sp. a, 436 & ply sexi. Al
sp. B, 436 & pl. xxi.

Hayeswater (Cumberland), origin of,
15.

Haystack Mountain (Montana), in-
trusive rocks of, 612,

Hemiaster bufo, 143.

GENERAL INDEX.

789

Hesto (Faeroe), lenticular lavas of, 338
fig.

Heteroceras Reussianum, 74 & pl. ii. ;
H. sp. (Chalk Rock), 75 & pl. ii.
Hexagonal arrangement of surface-

stones in Arctic areas, 738.
Hicks, Henry, elected President, xxiii. ;
on the Morte Slates and Associated
Beds, in North Devon & West
Somerset: Pt. I., 254-270 w. map,
sections, & pls. x.—xi. (fossils).
Hill, Rev. Edwin, on Transported
Boulder Clay, 8302-306 w. sections.
Hill, W., & A. J. Jukes-Browne, a
Delimitation of the Cenomanian :—
being a Comparison of the Corre-
sponding Beds in South-western
Hingland and Western France, 99-

_ 177 w. sections, lists of fossils, &
pl. v. (fossils).

Hill Farm (Dundry), sections deser.,
683, 684.

Hinde, G. J., receives Barlow-Jame-
son Fund Award for J. Wright,
xlix; Descriptions of New Fossils
from the Carboniferous Limestone :
I. On Pemmatites constipatus, sp.
nov., a Lithistid Sponge; II. On
Paleacis humilis, sp. nov., a new
Perforate Coral, with Remarks on
the Genus; III. On the Jaw-
apparatus of an Annelid, Humnicites
freidig, sp. noy., 438-451 & pls.
XXii.—xxiil.

Hippopotamus - bones
river-gravels, 499.

Hohe Rhonen (Switzerland), molasse-
depression betw. Etzel and, 572
fi

in Derwent

g.
Holaster planus-chalk, phosphatic, at
Lewes, 463; H. p.-zone, name for

Chalk Rock, 98.

Holaster suborbicularis, 144; H. sp.
(Cenomanian), 144.

Holland, Pliocene deposits of, 748-
781.

Holseer Cove (Cornwall), gneissoid &
other rovks of, 47.

Homalonotus (?) punctillosus, 411.

Homolopsis fichardsoni, sp. nov., 224.

Honduras, British, seismic pheno-
mena in, 667 fig.

Hongg (Geticailatay, glacial deposits
of, 565.

Hooken Cliff (Devon), section descr.,
118 & vert. sect. 112; minute
structure of Cenomanian ati 137.

Hornblende in altered granophyres ,
324, 326 & pl. xiii.

Hornblende-andesite of Hill of Allen,
602 fig.

790

Hornblende-gneiss & schist in Eastern
Sutherland, 688; inclusions in
foliated granite, 646 fig.; veins of
granite & pegmatite in, 647 fig.

Hornblende-schists of Lizard district,
genesis of, 18; relations of same
to serpentine z0id., 31 figs.

Horne, J., and E. Greenly, on Foliated
Granites and their Relations to the
Crystalline Schists in Eastern
Sutherland, 633-648 figs.

Hosking, G. F., obituary of, Ixxi.

Hulke, J. W., obituary of, liv.

Hull, Edward, Observations on the
Geology of the Nile Valley, and on
the Evidence of the greater volume
of the River at a former period,
308-319 w. sections.

Hume, W. F., Lyell Fund Award to,
xlvii.

Hundleby (Lincolnshire) brickyard,
section descr., 204.

Huxley, T. H., obituary of, lxiii.; por-
trait presented by Sir J. Evans,
CxxV.

Hydnopora (?) cyclostoma, its relation-
ship w. Paleacis discussed, 444 e¢
seqq.

‘ Hydrocratic’ movemeiits, 553.

‘ Hypabyssal’ rocks, 613.

Hysgeir (Hebrides), columnar pitch-
stone of, 371.

Tee, floating, geol. effects of its action,
732 et segq.

Tce-scratched stones of Kolguev Is-
land, 55, 62.

Iceland, recent volcanic action in,
illustrative of history of basalt-
plateaux of North-western Europe,
395.

Idaho (U.S.A.), map showg. dis-
tribution of volcanic rocks in,
pl. xxix.

Iddings, J. P., on Extrusive and
Intrusive Igneous Rocks as Pro-
ducts of Magmatic Differentiation,
606-617 & pl. xxix. (map).

Ilfracombe (North Devon), Ilfracombe
Beds at, 262.

Illenus Bowmani, 411; do. var.
brevicapitatus, 412 & pl. xx.; do.
var. longicapitatus, 412 & pl. xx. ;
-I. cxeus, 418; I. fallax, 413; 7
galeatus, sp. nov., 414 & pl. xx.;
J. Remeri,. 4138; J. sp. 416 &
pl. xx.

India, seismic phenomena in, 606 &
pl. xxxi. (map).

Inferior Oolite, see Oolite.

GENERAL INDEX.

[Nov. 1896,

Infra-Cretaceous, comparison of
Yorkshire & Lincolnshire strata,
facing 192 ; subdivisions in Lincoln-
shire, 194.

Ireland (South-eastern), seismic phe-
nomena in, 655.

Tronshot Oolite at Dundry, geographi-
cal extent of, 709.

Tape tone pisolitic, at Bryn Poeth,

ie

Isopoda, known fossil, xciii.

Jamaica, seismic phenomena in, 667
(map). i

Johnston, Frank, obituary of, lxxxi.

Jones, T. R., on Microzoa in Marl
and Silts from Barry Dock, 485.

Jovet, Mont (Savoy), ‘schistes lustrés’
of, 1-11 w. map.

Jukes-Browne, A. J.. & W. Hill, A
Delimitation of the Cenomanian :—
being a Comparison of the Corre-
sponding Beds in South-western
England and Western France, 99-
177 w. sections, lists of fossils, &
pl. v. (fossils).

Jurassic (?) plant-remains from Kol-
guey, 61.

Kaltboden (Switzerland), section at,
571.

Kashpur (Russia), Petchorian Series
near, 544.

Kedleston Valley (Derby), gravels in,
504.

Keisley Limestone, fauna of the, 407-
437 & pls. xx.-xxi.

Kennack Cove (Cornwall), micro-
scopic structure of granulitic rocks,
23.

Kilcobben Cove (Cornwall), inclusions
in hornblende-schist 8S. of, 20.

Kildare Inlier, 587-605 figs. & pl.
XXVlil.

Kildonan (Sutherland), geology of
district, 642.

Kildown Point (Cornwall), two ser-
pentines at, 46.

Killwangen (Switzerland),
deposits of, 564.

Kilmartin (Skye), columnar sill intru-
sive in Jurassic strata H. of, 374.

Kimeridge Clay in Yorkshire & Lin-
colnshire, 193.

Kimeridgian & Aptian, classification
of strata between, 542-554 & pl.
XXxvii.

Kinbrace (Sutherland), geology of
district, 642.

Kirktomy (Sutherland), geology of
country betw. Armadale and, 636.

glacial

‘Vol: 52. |

Knapton (Yorks.), Speeton Beds nr.,
185.

Kola Peninsula (Russian Lapland),
glacial geology of, 726.

Kolguev Island, glacial geology of,
52-58 ; erratic boulders from, 58-
63; terrace-making in, 724.

Kom Ombo (Hgypt), terrace of Old
Nile mud nr., 314 fig.; old river-
channels at, 316.

Kostin Schar (Novaya Zemlya), is-
lands in, connected by a glaciated
ridge covered w. shingle, 734 fig.,
736; rock-specimens from, 744,
745.

Kissnacht (Switzerland), glacial de-
posits of, 565; section in ravine,
566.

Kynance Cove (Cornwall), relations
of serpentine to hornblende-schist
in, 38 et seqg.

La Héve, Cape (Normandy), study of
cliffs betw. Brunval and, 115; sec-
tion below Cenomanian at, 119;
vert. sect. in Cenomanian at, facg.
124.

Lagena globosa, 488 ; L. levis, 487.

Lake, Philip, Murchison Fund award
to, xliv.; on the British Silurian
species of Acidaspis, 2385-245 &
pls. vii.—viii.; and S. H. Reynolds,
on the Lingula-Flags and lgneous
Rocks of the Neighbourhood of
Dolgelly, 511-522 w. wap (pl. xxiv.)
& sections.

Lake-basins,
580.

Lakeland, tarns of, 12-15 figs,

Lamellibranchiata, Cenomanian, 149.

Lamplugh, G. W., on the Speeton
Series in Yorkshire and Lincoln-
shire, 179-218 w. map & correl.
tables.

Lampusia (?) sp. (Chalk Rock), 93 &

iv.

Land-surfaces, submerged, at Barry,
474.

Lavas of Tertiary volcanic plateaux in
North-western Europe, 332.

Lawrence, P. H., obituary of, lxxvii.

Le Mans (Sarthe), Cenomanian se-
quence, 136.

League Hole (Suffolk), sections N.
of, 303; do. in little headland nr.,
304.

Lebanon, Calais Newboldi from Cre-
taceous of, 229-234 & pl. vi.

Lee Bay (North Devon), 261.

Lester, Rev. Lester, obituary of, lxxx.

Leucosiad, structure of, cxii,

Subalpine, origin of,

GENERAL INDEX.

TOL

Level, proof of changes of, in Northern
Norway, 721.
Lewes (Sussex),

from, 463.

Library, lists of donors to, xiv.

Library Committee, Report for 1895,
xii.

Lichas affinis, 427 ; L. bifurcatus, sp.
nov., 431 & pl. xxi.; L. bulbiceps,
428 & pl. xxi.; L. conformis, var.
keisleyensis, nov., 427 & pl. xxi.;
L. hibernicus, 428; L. Jaxatus,
427.

Lima Hoperi, 152; L. simplex, 152.

Limmat gravel-beds, 564.

Limnicythere inopinata, 486.

Lincolnshire & Yorkshire, Speeton
Series in, 179-220.

Linear marks in a sedimentary rock
[abs. ], 461.

Lingula mortensis, sp. nov., 266 &

eee

poate of the neighbourhood
ot Dolgelly, 511-522 figs. & pl. xxiv
(map).

Lion Rock (Lizard), relations of

_ granulite & serpentine nr., 27 fig.

Lissoceras ? subradiatum, 701.

‘Lit par lit’ introduction of granitic
materials into schists, 634 et seqgq.
Lizard district (Cornwall), serpentine,
gneissoid, & hornblende-rocks of,
17-49 figs. & pl. i. (microscope-sec-

tions).

Llanddona (Anglesey),
shales at. 628.

Llandeilo Limestone near Caermar-
then, 530.

Llandovery rocks of Conway, 273-288
w. map & sections.

Llanvirn Beds near Caermarthen, 527 ;
compared w. do. elsewhere, 533.

London Clay in Dorset, 491.

Loom Island (Novaya Zemlya), rock-
specimen from, 746.

Lovén, Sven, obituary of, lxxii.

Loxoconcha elliptica, 485.

Lulworth Cove (Dorset), section descr.,
109; & vert. sect. facg. 114.

Lyell Geological Fund Award to W.
F. Hume, xlvii.; to C. W. Andrews,
xlviil.

Lyell Medal awarded to A. Smith-
Woodward, xlv.

Lyell Medallists and recipients of
awards trom fund, list of, xxx.

phosphatic chalk

Ordovician

Macleod’s Maidens (Skye), banded ba-
salt at, 336 fig.
Macrura, known fossil, xeviii.

792 GENERAL INDEX.

Maes Knoll (Dundry), sections deser.,
684, 686; table of sections from, to
western end of hill, 694.

Magmatic differentiation, extrusive
and intrusive igneous rocks as pro-
ducts of, 606-617 & pl. xxix. (map).

Maltese Islands, Globigerina-lime-
stones of, 461; seismic phenomena
in, 666 (map).

Mammalian remains in old Derwent
river-gravels, 497-509 figs.

Manacle Point (Cornwall), gabbro nr.,
43 fig.

Mantell, W. B. D., obituary of, Ixxiv.

Marden Hill (Lincolnshire) brickyard,
section descr., 204.

Marlstone Rock at Dundry, 705.

Marr, J. E., Additional Notes on the
Tarns of Lakeland, 12-15 figs.

Matutide, structure of, cxi.

Metcalfe, A. T., Gypsum Deposits of
Notts & Derbyshire [abs.], 461.

Mica-schist, ‘wavy,’ in Hastern Suther-
land, 642.

Microcyathus, gen. nov. proposed,
447

Micropora, 2 spp. (Cenomanian), 146.

Miller, Hugh, obituary of, lxxx.

Milne, John, his researches on the
propagation of earthquakes, xc.

Milnes, W.S., obituary of, lxxxii.

Mitchell, Joseph, obituary of, Ixi.

Modiolopsis barricanensis, sp. Nnov.,
269 & pl. xi.

Mollusca of the Chalk Rock, 68-98 &
pls. ii.—iv.

Monocarpinea, known fossil, xcix.

Montana (U.S.A.), map showg. dis-
tribution of volcanic rocks in, pl.
a Obes

Montessus de Ballore,; F. de, on Seis-
mic Phenomena in the British
Empire, 651-668 figs. & pls. xxx.
XXxili. (maps).

Moonen Bay (Skye), upper part of
sill, showing divergence of veins,
317 fig.

Mortagne (Orne), Cretaceous nr., 132,
133, 184; vert. section, facg. 172.
Morte Slates in North Devon & West
Somerset, 254-270 figs. & pls. x.—xi.

(fossils).

Morthoe (North Devon), exposures
betw. Woolacombe, Bittadon, and,
257, 260 fig.

Moulineaux (Calvados), section descr.,
126.

Mullacott (North Devon), Morte
Series at, 262.

Mullion Cove (Cornwall), hornblende-
schists in quarry nr., 20.

[Nov. 1896,

Murchison Geological Fund Award to
Philip Lake, xliv.

Murchison Medal awarded to T.
Mellard Reade, xliii.

Murchison Medallists and recipients
of awards from fund, list of, xxix.
Museum of Geol. Soc., proposed traus-

. ference of, x., exxiv.
Mylonitic seam in Tairffynnon Breccia,
626 fig.

Mynydd Gader (Dolgelly), Lingula-

flags and igneous rocks of, 513, 519.

Nagelfluh, cavernous, characteristics
and origin of, 557.

Names of Fellows read out, exxyv.,
CXXvil.

Nant Ceunant (Dolgelly), Lingula-
flags of, 518; do. HK. of same,
515.

Natica (Naticina) vulgaris, 91.

Nautilus sublevigatus, 73.

Necks, Tertiary volcanic, of Stromo,
343 et segg. & pl. xv.; in Portree
Bay, 346 et segg. ; in Canna Island,
Bol.

Neckarmount (Conway),
ur., 283

Neckwatowa River (Novaya Zemlya),
view showg. rock-erosion, 737 ; rock-
specimens from, 745.

Neocomian (Lower), in Russia, 546 ;
Sands (Upper) nr. Cape La Heve,
116.

exposures

Neolithic flint-implements found at
Barry Dock, 479.

New Zealand, seismic phenomena in,
659, 660 (map).

Nickel-bearing serpentine from Riffel-
horn, 452 w. chem. anal.

Nile Valley (Egypt), geology of, 308-
319 w. sections.

Nodules, phosphatic, ete., formation
of, 198.

Normandy, list of Cenomanian fossils
from, 166.

Norway (Northern), proof of changes
of level in, 721.

Norwich (Norfolk), section to Sutton,
753; section to Greenlo, 753.

Norwich Crag, its origin etc., dis-
cussed, 767.

Notre Dame de Courson (Normandy),
section nr., deser., 130.

Nottinghamshire, gypsum-deposits of,
461.

Novaya Zemlya, glacial geology of,
731; rock-specimens from, 744.

Nubian Sandstone, its relation to
granite & schist of Assuan, 311; age
of, 311,

Vol. 52.]

Nuneaton (Warwickshire), Olenellus-
zone at, vi.

Ogo-dour (Cornwall), serpentine &
hornblende-schist ur., 35 fig.

Ogygia marginata, sp. nov., 538 &
pl. RXV1.

Olenellus-zone at Nuneaton, vi.

Olivine (?) -basalt of Grange Hill,
597 & pl. xxviii.

Oolite (Inferior), so-called, of Dundry
Hill, 669-720 w. tables, section, &

map.

Oppelia subradiata, 701.

Orbez (Normandy), section nr., deser.,
129.

Ordovician Series in Anglesey, 626.

Orne (Northern), correlation of Ceno-
manian w. that of Calvados and
Sarthe, 129; (Southern) do., 134 ;
minute structure of Cenomanian in,
141.

Orthis rustica, 268 & pl. xi.

Ostracoda in Lewes phosphatic Chalk,
470; in deposits at Barry Dock,
485.

Ostrea canaliculata sew lateralis, 149.

Oxyrhyncha, structure of, cxii.

Oxystomata, structure of, cxi; known
fossil, exii.

Pachydiscus peramplus, 79.

Paleacis, remarks on genus, 443.

Paleacis cuneiformis, 445 & pl. xxiii. ;
P. humilis, sp. nov., 440 & pl. xxiil. ;
P. obtusa, 446 & pl. xxiii.

Paleocorystes Harveyi, sp. nov., 225.

Palzontographical Society, jubilee of,
Ixxxvi.

Palagonite, alteration of, 66.

Palinuride, structure of, & known
fossil, civ.

Parabolinella, sp. nov., 537 & pl. xxvi.

Pare Bean Cove (Cornwall), relations
of serpentine to hornblentle-schist,
35 fig., 36 & pl. i.

Pavlow, A. P., on the Classification
of the Strata between the Kime-
ridgian and Aptian, 542-554 &
pl. xxvii.

Peat-beds at Barry Dock, 476 ez seqq.

Pecten Dutemplei sew Galliennei, 150;
P. elongatus, 151; P. interstriatus,
149; P. Passyi, 150; P. cf Puzo-
sianus, 151; P. subacutus, 151; P.
subinterstriatus, 150; P.sp. (Ceno-
manian), 152.

Peltura punctata, sp. noy., 535 &
pl. xxvi.

Pemmatites constipatus, sp. nov., 438
.& pl. xxii.

GENERAL INDEX.

793

Penzidea, known fossil, ci.

Permo-Carboniferous Glacial Beds in
Australia, 289-301] & pl. xii.

Petchorian Series near Kashpur, etc.,

Phillipsinella parabola, 435.

Phosphatic Chalk from Lewes, 463.

Phyllocarida, known fossil, xev.

Pickwell Down Beds, 258 e¢ segg.

Pinhay (Devon), section deser., 110,
112.

Pisolitie ironstone at Bryn Poeth,
627.

Pitchstone,
371.

Plagiolephus vancouverensis, sp. nov.,
©)e

columnar, of Hysgeir,

Plant-remains in. mammaliferous gra-
vels at Allenton, 499; Mesozoic,
from Kolguev, 61.

Plateau -lavas, Tertiary, of North-
western Europe, 332. :

Plesiosaurian skull, structure of the,
246-253 figs. & pl. ix.

Plesiosaurus dolichodeirus, 248; Pl.
macrocephalus, 246 & pl. ix.

Plesioteuthis Fraasit, sp. nov., 233.

Pleuroceras, aff. nudum, 702.

Pleurotomaria (Leptomaria) perspec-
tiva, 86 & pl. i.

Pliocene deposits of Holland, and
their relation to English and Bel-
gian Crags, 748-781.

Pluvial Period in Egypt, 318.

Podophthalmata, Cretaceous, from
Vancouver and Queen Charlotte
Islands, 221-228 figs.

Poederlien mollusca, lists of, 756,
757.

Polbarrow Cove (Cornwall), serpen-
tine and granulite in, 29, 30 figs.
Poltesco.Cove (Cornwall), serpentine

and granulite nr., 29 fig.

Polycarpinea, structure of, ec.

Polystomella striatopunctata, 488.

Polyzoa, Cenomanian, 145.

Porthallow Cove (Cornwall), relations
of serpentine to hornblende-schist
in, 37, 38.

Porthkerris (Cornwall), serpentine at,

Porthoustock Cove (Cornwall), inclu-
sions in hornblende-schist at, 19
figs. ; gabbro S. of Point, 43 fig.

Portlandian, its existence at Speeton
denied, 182.

Portree Bay (Skye), Tertiary volcanic
necks in, 346 ez seqq.

Portskerry (Sutherland), geology of
poe between Armadale and,
639.

794

Portunidz, known fossil, exv.

Potstone Point (Cornwall), relations
of serpentine to hornblende-schists
nr., 31 e¢ seggq. fig. & pl. 1.

Preglacial Subalpine valleys in
Switzerland, 574.

Preller, C. S. Du Riche, Glacial
Deposits, Preglacial Valleys, and
Interglacial Lake-formations in Sub-
alpine Switzerland, 556-585 figs.

Prestwich, Sir J., death announced,
CXXVi.

Prionocyclus Neptuni, 77 & pls. i1.-iii.

Pterinea mortensis, sp. nov., 269 &

1x.

Parcicearas Smithi, sp. nov., 74 &

iil:
Pygurus lampas, 145.

Quartz-schist in Eastern Sutherland,
642.

Queen Charlotte Island, Cretaceous
podophthalmata from, 221.

Rackledown or Rattledowun Farm
(Dundry), section descr., 692 ; table
of sections from, to Dundry Church,
696.

Ranininea, known fossil, exi.

Rastrites maximus-zone at Conway,
279, 284.

Reade, T. Mellard, Murchison Medal
awarded to, xliii.

Reading and Woolwich Series in
Dorset, 490.

Red Chalk in Yorkshire, 185 e¢ segq.

Reed, F. R. Cowper, the Fauna of the
Keisley Limestone, Part I., 407-437
& pls. xx.-xxi.

Reid, Clement, on shells & plants
from Barry Dock, 479 e¢ segg.; the
Eocene Deposits of Dorset, 490-
495; on plant-remains in mamma-
liferous gravels at Allenton, 499.

Remopleurides Colbii, 410; R. longi-
costatus, 410.

Reussianum-zone, name proposed for
Chalk Rock, 70.

Reynolds, 8. H., and Philip Lake, on
the Lingula-Flags and Igneous
Rocks of the Neighbourhood of
Dolgelly, 511-522 figs. & pl. xxiv.
(map); and C. I. Gardiner, on the
Kildare Inlier, 587-605 & pl. xxviii.

Rhine, ancient, connexion betw. East
Anglia and, 770; formation of delta,
775.

Rhynchonella alata sive dimidiata,
146; R. dundriensis, 702; A.

GENERAL INDEX.

[Nov. 1896,

Lewisti(?), 268 & pl. xi.; R. Strick-
landi (?), 268 & pl. xi.; R. Wiestii,
aie

Rhyolitic lava of Yellowstone Park
region, 614.

Riasan (Russia), Upper Jurassic and
Neocomian succession of, 545.

Riffelhorn (Switzerland), nickel-bear-
ing serpentine w. fulgurites from,
452.

Rivers of volcanic period in North-
western Europe, 354.

- River-channels, old, in the Nile Valley,

315; r.-terraces ibid., 312.

Rockham Bay (North Devon), Morte
Series in, 261.

Rogatcheva Bay (Novaya Zemlya),
731; rock-specimens from, 744.
Rose Mill Farm (Conway), exposures

nr., 283.

Rotalia Becearii, 488.

Rudh’ an Iasgaich (Skye), sills at, 378
et segg.; section, 380.

Rudha Ghoiridh (Sutherland), gneisso-
granitic complex, 640 fig.

Russia, correl. of strata betw. Kime-
ridgian and Aptian w. those of
Western Kurcpe, table facg. p.
548.

Ritimeyer, L., obituary of, lxxix.

Rutley, Frank, on the Alteration of
certain Basic Eruptive Rocks from
Brent Tor, Devon |abs.], 66.

Ste. Adresse (Normandy), section ur.,
descr., 117.

St. Jouin (Normandy), Cretaceous
succession at, 123 & vert. sect. facg.
124.

St. Julien de Mailloc (Normandy),
section nr., deser., 128.

St. Kilda, basalt-veins traversing gra-
nophyre, 383 fig.; gabbros ete. of,
388 ; granophyre-intrusions in, 389
et seqq.

St. Martin de Liette (Normandy),
section descr., 127.

St. Paul de Courtonne (Calvados),
Cenomanian nr., 128.

Salenia Clarkii, 145; S. petalifera
var., 145.

Sanday (Hebrides), sedimentary rocks
interbedded w. Tertiary lavas in,
363 et segg. & pls. xvii—xix.

Sanders’s map of Dundry Hill, dis-
cussed, 718. ‘

Sando (Faeroe), dying out of lava-
beds, 338 fig.; reversed fault in,
402 fig.

Saporta, Gaston de, obituary of, liii.

ae

Vol. 52.]

Sarthe, correlation of Cenomanian w.
that of Orne and Calvados, 135.

Scaldisien molluscea, lists of, 756, 757,
764.

Scandinavian ice-sheet, its terminal
moraine, 774.

Scaphites Geinitzi, 81 & pl. iii.

Scavaig, Loch (Skye), gabbros around,
384 et seqq.

Schindelleggi (Switzerland), glacial
deposits of, w. map, 570; trans-
verse section of Sihl Valley at, 573.

*Schistes lustrés’ of Mont Jovet, 1-11
w. map.

Schists, crystalline, in relation to
foliated granites of Eastern Suther-
land, 633-648 figs.

Schizopoda, structure of, xcviil.

Scorr (Skye), section of volcanic vent,
ete. at, 347.

Scotland, seismic phenomena in, 654,
656 (w. map).

Scotten Dale (Yorks.),sectn.descr.,189.

Scrobicularia-clay at Barry Dock, 477.

Secuir of Higg, possible: identity of
ancient river w. that of Canna and
Sanday, 370.

Seyllaridea, structure of, & known
fossil, ciil.

Sedimentary material interbedded
w. Tertiary lavas, 339 e¢ seqq.,
354 et seqg.; sedim. rock, linear
marks in a, 461.

Sehél Island (Egypt), section nr., 317.

Seismic phenomena in the British
Empire, 651-668 figs. & pls. xxx.-
XXXili. (maps).

Seismicity defined, 652.

Seismographical and _ seismological,
distinction in terms, 651.

Serpentine of Lizard District, its rela-
tions to granulite & hornblende-
schists, 24 figs. & pl.i.; foliation
& other structures in, 44; two
varieties of, 46; post-Archean age
of, 48; nickel-bearing, from Rif-
felhorn, 452 w. chem. anal.

Shelfin (North Devon), Morte Series
at, 262.

Sihl Valley (Switzerland), transverse
section of, at Schindelleggi, 573.

Silicon atom, its group-forming
powers, 647. .

Sills, Tertiary basic, in North-western
Europe, 373.

Sillimanite in rocks of Eastern Suther-
land, 642 et seqq.

Silurian species of <Acidaspis in
Britain, 235-243 & pls. vii.-viii. ;
comparison w. Swedish & Bo-
-hemian faunas, 244,

GENERAL INDEX,

795

Sinfin Moor (Derby), section descr.,
502.

Skeat, Ethel G., & Margaret C. Cros-
field, on the Geology of the Neigh-
bourhood of Caermarthen, 523-541
& pls. xxv.—xxvi.

Slade (North Devon), 261.

Slatter, T. J., obituary of, lxx.

Smithson (North Devon),
Series at, 264.

Morte

*Snow-foot protecting coast-lines, 54.

Somerset (West), Morte Slates, ete. in,
254-270 figs. & pls. x.—xi (fossils).
Southerham Pit (Lewes), phosphatic

chalk from, 463.

Sowandeni, Mount (Kolguev), 53.

Special General Meeting, exxiv.

Speeton Series in Yorkshire and Lin-
colnshire, 179-220 ; table of cepha-
lopoda facing 184; map, 187;
correlation-tables facg. 192, 212.

Spencer, J. W., on the Geographical
Evolution of Jamaica [title only],
xxiv.

Spherexochus latirugatus, sp. nov.,
423 & pl. xx.; Sph. mirus, 423.

Spheroceras Brocchi, 701.

Spherocoryphe granulata, 423.

Sphenopoterium, a synonym of Pale-
acis, 443.

Spilsby Sandstone, 199; basement-
bed of, 195. y

Spirifera Hamlingii, sp. nov., 268 &
pl. xi.

Spitsbergen, glacial geology of, 739.

Sponge-spicules in grit of Careg Onen,
619, 620 fig.

Squillidz, known fossil, xevii.

Staurocephalus Murchisoni, 425.

Stauronema Carteri, 142.

Stephanoceras contractum, 701.

Stockdale Shales, equivalent(? in
Kildare, 596.

Stomatopoda, structure of, xevi.

Stones, hexagonal arrangement of, in
Arctic areas, 738.

‘ Stone-bogs,’ 738.

Stonyhurst (Lancs.). Paleacis humilis,
sp. nov. from, 440 & pl. xxiii.

Stor Tamso (Norway), glacial geolocy
of, 723 ; quartz-schists (?) from, 741.

Storrie, John, Barlow-Jameson Fund
Award to, l.

Strahan, A., receives Barlow-Jameson
Fund Award for J. Storrie, 1; ona
Phosphatic Chalk with Holaster
planus at Lewes, 463-470 ; on Sub-
merged lLand-surfaces at Barry
(Glamorganshire), 474-484 w. map
& section.

Strath (Skye), altered granophyres

796

of, 320-330 w. map & pis. xiii—
Xiv. (microscope-sections).

Strathy Point (Sutherland), granular
gneiss, etc. of, 641 fig.; inclusions
of hornblende-schist in foliated
granite, 642 fig.

Striation, glacial, in N.E. Anglesey,
629.

Stricklandinia lirata, 266 & pl. x.

Strigoceras compressum, 701.

Stromo (Faerde), sills & volcanic
necks of, 343 e¢ segg. & pl. xv.;
sections, 380, 381.

Subalpine Switzerland, glacial deposits,
ete. in, 556-586 figs.

Submerged land-surfaces at Barry,
474, °

Sudero (Faerde), plant-beds, &c.
interstratified with basalts, 340 fig.

Suess, Eduard, Wollaston Medal
awarded to, Xxxix.

Suishnish Point (Raasay), grano-
phyre-sill resting on Lower Lias
shales, 395 fig.

Surface-stones in Arctic areas, hex-
agonal arrangement. of, 738.

Sutherland (Eastern), foliated granites
in relation to crystalline schists of,
633-648 figs.

Sutton (Suffolk), section to Yarmouth,
751; section to Norwich, 753.

Sviatoi Nos (Kola Peninsula), boulder-
covered area nr., 728 fig.; diagram
of boulders in _ hollows, 729 ;
boulder-specimens from, 742.

Svind (Faeroe), lenticular lavas of,
338 fig. ; reversed fault in, 402 fig.

Swanage (Dorset), vert. section facg.,

4

Switzerland, Subalpine, glacial de-
posits, etc. in, 556-586 figs.

Tairffynnon Breccia, mylonitic seam
in, 626 fig.

Talisker Bay (Skye), dying-out of
lava-sheets, 337.

Talmage, J. E., Notes concerning
certain Linear Marks in a Sedi-
mentary Rock [abs.], 461.

Tan-y-gader (Dolgelly), Tremadoc
Beds, ete. of, 514.

Tarannon Shales, at Conway, 280;
correlated w. those of other areas,
285:

Tarns of Lakeland, 12-15 figs.

Tasmania, seismic phenomena in,
661, 662 (map).

Tayler, J. W., obituary of, Ixxxi,

Taylor, J. E., obituary of, lxxv.

Tealby Clay, 207.

Tealby Limestone, w. the
Clay and ‘ Roach,’ 209.

Upper

GENERAL INDEX,

[Nov. 1896,

Terebratula arenosa, 148; T. capil-
lata sew squamosa, 148; T. aff.
infra-oolithica, 702; T. tornacensis,
147; 'T. Verneuilii, 148.

Terrace-formations in Norway, 722
et seqgg. ; in Kolguev Island, 724.

Tertiary basalt-plateaux of North-
western Europe, 331-405 figs. &
pls. xv.—xix.

Thalassinidea, structure of, & known
fossil, evi.

Thaumastocheles Zaleucus, structure
of, cvii ; kindred fossil forms,
cviil.

Thompson, Beeby, the Junction-beds
of the Upper Lias and Inferior
Oolite in Northamptonshire. —
Part I. Physical and Cheinical
[title only], cxxii.

Tiresias insculptus, 410.

Tornquistia, new subgen.proposed,435.

Torridon Sandstone in agglomerates &
conglomerates of Canna, 352, 356,
358 et segg.; altered by gabbros in
Skye, 385.

Torrin (Skye), ground-plan of basic
dyke at, 382.

Towle’s Quarry (Dundry), section
deser., 679.

Transported Boulder Clay, 302-307
figs.

Tremadoc Slates near Caermarthen,
525; compared w. do. elsewhere,
531.

Trias of Mont Jovet & its relations to
‘schistes lustrés,’ 5 é seqgq.

Trigonia affinis, 153; T. crenulata,
154; T. crenulifera, 154; T. debilis,
154; T. dunscombensis, 153; T.
Meyeri, 154; T. Vicaryana, 154.

Trilobites, gradual extinction of, xci;
tril. from the Keisley Limestone,
407-437 & pls. xx.—xxi.

Trochus beroescirense, sp. nov., 88 &
pl. iv.; Zr. Schliiteri, sp. nov:, 88
& pl. ii.

Tromsodal (Norway), diagram of
terrace-formations in, 722.

Turbo Geinitzi, sp. nov., 88 & pl. iv. ;
T. gemmatus, 89 & pl. iv.; T. g.
var. a, 90.

Turgi (Switzerland), glacial deposits
nr., 560 w. map.

Turonian strata, betw. St. Jouin &
Brunvyal, 125.

Turrilites Bechii, 156.

Tyler, Charles, obituary of, lxxvii.

Ukanskoe River (Lapland), views on
and near, 727, 728 fics. ; tundra w.
boulders nr., 730 tig.; rock-speci-
mens from, 742.

Vol. 52.]

‘Underplight’ in Derbyshire, 504 e¢
seqq.

Utrecht (Holland), boring at, 762.

Vancouver, Cretaceous podophthal-
mata from, 321.

Vardo (Norway), raised beach on,
724.

Vents, Tertiary volcanic, in North-
western Europe, 342.

Vesicles in Tertiary lavas, 333.

Vimoutiers (Orne), section in Ceno-
manian descr., 130; list of fossils
from Craie de Rouen idid., 132;
vert. sect. facg. 172.

Virgin Islands, seismic phenomena in,
666.

Vol-anie rocks of Idaho, Montana,
and Wyoming, 609 e¢ seqq.

Volgian stages in Russia, 548.

Wales, seismic phenomena in, 655.

Walton (Essex), list of Scaldisien &
Poederlien mollusea, 756.

Watendlath Tarn (Cumberland),
origin of, 12.

Water-bearing beds of Dundry Hill,
713.

Wealden (?) plant-remains

~ Kolguev, 61.

Wellow (Somerset), section descr.,
712.

Wenlock Shales at Conway, 282; cor-
rel. w. those of other areas, 286.
West Down (North Devon), section

to Capstone Point, 263.
West Indies, seismic phenomena in,
666, 667 figs. & pl. xxxili. (map).
Weston-on-Trent (Derby), high-level
river-gravel, 507 fig.

Wettingen (Switzerland), glacial de-
posits, w. section, 563.

Whidborne’s list of Dundry mollusca,
703.

Whitecliff (Devon), section deser., 113.

Wight, Isle of, Cenomanian succession
in, 103 & vert. sections facg. 114 &
172; minute structure of Upper
Greensand in, 138.

Wild Duck Creek (Victoria), Glacial
Beds at, 295.

Williams, J. H., obituary of, lxxxi.

Wilson, E., and S. 8S. Buckman, on
Dundry Hill: its Upper Portion,
or the Beds marked as Inferior
Oolite (g5) in the Maps of the
Geological Survey, 669-720 w.
tables, section, & map,

from

GENERAL INDEX.

797

Wollaston Donation Fund Award to
Alfred Harker, xli.

Wollaston Medal awarded to Eduard
Suess, Xxxix.

Wollaston Medallists, list of, xxvii;
recipients of awards from fund,
XXVlii.

Wood, E. M. R., and G. L. Elles,
on the Llandovery and Associated
Rocks of Conway (North Wales),
273-288 w. map & sections.

Woods, Henry, the Mollusca of the
Chalk Rock, Part I. 68-98 & pls.
ii.-iv.

Woodward, A. Smith, Lyell Medal
awarded to, xlv.

Woodward, Henry, address to medal-
lists, xxxix et segg.; obituaries of
deceased Felluws, ete., lii; Presi
dential Address on the Life-history
of the Crustacea in Later Paleozoic
and in Neozoiec Times, xci—cxvili ; on
some Podophthalmatous Crustacea
from the Cretaceous Formation of
Vancouver and Queen Charlotte
Islands, 221-228 figs.; on a Fossil
Octopus (Calais Newboldi, J. de C.
Sby. MS.) from the Cretaceous of
the Lebanon, 229-234 & pl. vi.

Woolacombe (North Devon), expo-
sures betw. Bittadon and, 257;
section to near Morthoe, 260.

Woolscott Barton (North Devon),
Morte Slates at, 264.

Woolwich and Reading Series in
Dorset, 490.

Wright, Joseph, Barlow-Jameson
Fund award to, xlix.

Winsch, E. A., obituary of, Ixxviii.

Wirenlos (Switzerland), glacial de-
posits at, 564.

Wyoming (U.S8.A.), map showing
distribution of volcanic rocks in,
pl. xxix.

Xenocryst & xenolith, terms ex-
plained, 323.
Yarmouth (Norfolk), section to

Sutton, 751.
Yoredale Beds, Pemmatites consti-
patus from, 438 & pl. xxii.
Yorkshire & Lincolnshire, Speeton
Series in, 179-220.

Zeilleria anglica, 702; Z. Oppeli, 702.
Ziirich Valley, map of, 658; profile
of 577 ; transyerse sections of, 579.

END OF VOL, LI,

Uae fs | PRINTED BY TAYLOR AND FRANCIS,
RED LION COURT, FLEET STREET.

PROCEEDINGS

OF THE

GEOLOGICAL SOCIETY OF LONDON.

SESSION 1895-96.

November 6th, 1895.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

Samuel John Truscott, Esq., Assoc.R.S.M., P.O. Box 590,
Johannesburg, Transvaal, South Africa, was elected a Fellow of
the Society.

The List of Donations to the Library was read.

The Prestpenr announced that the Council had temporarily
appointed Mr. Clyde H. Black to the post of Assistant-Clerk.

The following communications were read :—

1. ‘The Serpentine, Gneissoid, and Hornblendic Rocks of the
Lizard District.’ By T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S.,
Professor of Geology and Mineralogy in University College, London.

2. ‘The “ Schistes Lustrés ” of Mont Jovet (Savoy).’ By J. W.
Gregory, D.Sc., F.G.S.

The following specimens, etc., were exhibited :— »

Rock-specimens and microscope-slides, exhibited by Prof. 'T. G.
Bonney, D.Sc., LL.D., F.R.S., in illustration of his paper.

Rock-specimens and microscope-slides, exhibited by Dr. J. W.
Gregory, F.G.S8., in illustration of his paper.

Specimen of a Lithistid Sponge from the Upper Chalk, found in
VOL. LII. a

ri PROCEEDINGS OF THE GEOLOGICAL SocIETY. [Feb. 1896,

Flint Gravel at Croydon, and exhibited by W. F. Stanley, Esq.,
F.G.S., F.R.A.S.

Book of Photographs of Gohna Lake (Kumdua, Himalayas), before
and after flood, exhibited by Dr. W. T. Blanford, F.R.S., Treas.G.S.,
on behalf of C. L. Griesbach, Esq., C.I.E., Director of the Geological
Survey of India.

Photographs illustrating structures in the ‘ Granulitic Series’ ;
and structures produced by deforming heterogeneous masses of
Clay, exhibited by J. J. H. Teall, Esq., M.A., F.R.S., Sec.G.S.

Maxilla of Portheus, from the Lower Chalk of Burham; and
Synhelia Sharpeana, from the Upper Chalk of Croydon, exhibited
by G. E. Dibley, Esq., F.G.S.

Sheets 9 and 13 of the Geological Survey Index Map (Scale,
1 inch=4 miles), presented by the Director-General of that
Survey.

November 20th, 1895.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

The Rev. Henry Arthur Hall, M.A., The Schoolhouse, Totnes,
South Devon, was elected a Fellow of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1, ‘ Additional Notes on the Tarns of Lakeland.’ By J. E. Marr,
Esq., M.A., F.R.S., Sec.G.8.

2. ‘Notes on the Glacial Geology of Arctic Europe and its
Islands.—Part I. Kolguev Island.’ By Col. H. W. Feilden, F.G:S. ;
with a ‘ Report on the Erratic Boulders from the Kolguev Beds,’
by Prof. T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S.

_ The following specimens, etc., were exhibited :—

Rock-specimens, plant- and other fossil remains from Kolguev
Island, exhibited by Col. H. W. Feilden, F.G.S., in illustration of
his paper.

Photograph of Mud Cracks (scale +) in Coal Measure mine-refuse
mud at foot of spoil-bank, No. 1 Mine, Spring Valley (Illinois),
U.S.A., exhibited by W. S. Gresley, Esq., F.G.S.

'

“—

+

Vol. 52.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. lii

December 4th, 1895.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

Samuel C. Barlow, Esq., Roman Road, Stockport; William
Boulton, Esq., A.R.C.S., Lecturer on Geology and Physiography in
the Mason College, Birmingham; William John Prinsep Burton,
Esq., Lea, Matlock Bath; the Rev. Henry Canham, LL.B. Cantab.,
Leathley Rectory, Otley; Allan Greenwell, Esq., Blyth House,
Frome,. Somerset; Karl Grossmann, M.D., F.R.C.8., 70 Rodney
Street, Liverpool; James Henry Hosking, Esq., Helred, Enfield ;
Edward Alfred Martin, Esq., 69 Bensham Manor Road, Thornton
Heath; Thomas Murdoch, Esq., J.P., Argentine Consul, Dundee ;
John Parkinson, Esq., 251 Camden Road, N.; Malcolm Paterson,
Esq., M.Inst.C.E., 35 Manor Row, Bradford, Yorkshire; Walter
George Ridewood, Esq., 80 Oakley Street, Chelsea, 8.W.; R. W.
Boothman Roberts, Esq., 63 Carisbrooke Road, Walton, Liverpool ;
and the Rev. E. Adrian Woodruffe-Peacock, Cadney Vicarage, Brigg,
were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Alteration of certain Basic Eruptive Rocks from
Brent Tor, Devon.’ By Frank Rutley, Esq., F.G.S.

_ 2. ‘The Mollusca of the Chalk Rock.—Part I. By Henry
Woods, Esq., M.A., F.G.S.

The following specimens, etc., were exhibited :—

Specimens and microscope-sections exhibited by Frank Rutley,
Esq., F.G.S., in illustration of his paper.

Drawings of Cretaceous Mollusca, exhibited by H. Woods, Esgq.,
M.A., F.G.S., in illustration of his paper.

Geological Survey of England and Wales, Vertical Sections:
Sheet 80, by A. Strahan, Esq., M.A., F.G.S., presented by the
Director-General of H.M. Geological Survey.

December 18th, 1895.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.
William Valentine Ball, Esq., B.A., King’s College, Cambridge ;

Edward Philip Binet, Esq., Assoc.M.Inst.C.E., 100 Victoria Street,
Westminster, 8.W.; Richard Herbert Lapage, Esq., M.Inst.C.E.,

lv PROCEEDINGS OF THE GEOLOGICAL socieTy. [Feb. 1896.

Oakfield, Langley Avenue, Surbiton ; W. T. Tucker, Esq., Parkside,
Loughborough, Leicestershire; David John Williams, Esq., Science
Master, County and Technical School, Narberth, South Wales; and
Francis Wood, Esq., M.Inst.C.E., 8 Bond Terrace, Wakefield,
Yorks., were elected Fellows; Prof. G. K. Gilbert, Washington,
D.C., was elected a Foreign Member; and Dr. A. Penck, Vienna,
was elected a Foreign Correspondent of the Society.

The List of Donations to the Library was read.

Mr. H. B. Woopwarp called the attention of the Society to
advance copies of certain maps exhibited by the Director-General
of the Geological Survey.

The following communications were read :—

1. <The Tertiary Basalt-plateaux of North-western Europe.’ By
Sir Archibald Geikie, D.Sc., LL.D., F.R.S.

2. ‘The British Silurian Species of Acidaspis.’ By Philip Lake,
Esq., M.A., F.G.S.

The following objects were exhibited :—

A series of specimens and microscopic slides illustrating the rocks
of the Inner Hebrides and St. Kilda; and a collection of photo-
graphs, sketches, diagrams, and maps, depicting the geological
structure of these islands and the Farée Isles, also a MS. geological
map (6-inch scale) of the island of Canna. Exhibited by Sir Archi-
bald Geikie, D.Sc., LL.D., F.R.S., in illustration of his paper.

Specimens of <Acidaspis, some exhibited by Philip Lake, Esq.,
M.A., F.G.S., in illustration of his paper, and others exhibited by
the Director-General of H.M. Geological Survey, in illustration of
the same paper.

Advance copies of the Geological Survey Index Map, Sheet 11,
and of a new edition (printed in colours) of Sheet 12; copies of
Sheet 249 (Drift and Solid), being the first map of the New Survey
of the South Wales Coal-field ; also a MS. copy of Sheet 81 (Raasay
and portion of Skye). Exhibited by the Director-General of H.M.
Geological Survey.

Sheet 341, New Series, l-inch map (with Drift), West Fleet
(Dorset). By A. Strahan, 1895. Presented by the Director-General
of H.M. Geological Survey.

7

|

Vol. 52.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. v

January 8th, 1896.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

George William Colenutt, Esq., Hanway Lodge, Belvedere Street,
Ryde; and John Collett Moulden, Esq., A.R.S.M., College Park,
Adelaide, South Australia, were elected Fellows of the Society.

The following Fellows, nominated by the Council, were elected
Auditors of the Society’s accounts for the preceding year :—BENNETrT
H. Broveu, Esq., and R. 8S. Hzrriss, Esq.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘A Delimitation of the Cenomanian, being a Comparison of
the Corresponding Beds in Southern England and Western France.’
By A. J.J ukes-Browne, Esq., B.A., F.G.S., and William Hill, Ksq.,
F.G.S.

2. ‘The Llandovery and Associated Rocks of Conway.’ By
G. L. Elles and E. M. R. Wood, Newnham College. (Communicated
by J. E. Marr, Esq., M.A., F.R.S., Sec.G.S.)

3. ‘The Gypsum Deposits of Nottinghamshire and Derbyshire.’
By A. T. Metcalfe, Esq., F.G.S.

The following specimens were exhibited :—

Fossils, rock-specimens, and microscope-sections, exhibited by
A. J. Jukes-Browne, Esq., B.A., F.G.S., and William Hill, Esq.,
F.G.S., in illustration of their paper.

January 22nd, 1896.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

Harry Graves, Esq., B.A. Oxon., 5 St. Oswald’s Road, West
Kensington, W.; A. W. Rogers, Esq., B.A., Christ’s College,
Cambridge; Alfred John Saise, Esq., C.E., Ventnor House,
Fishponds, Bristol; and Lionel Leigh Smith, Esq., B.A. Cantab.,
Crowham Manor, Westfield, Battle, Sussex, were elected Fellows
of the Society.

The List of Donations to the Library was read.
VOL. LII. b

vi PROCEEDINGS OF THE GEOLOGICAL society. [May 13896,

Mr. W. W. Warts, in the absence of Prof. Lapworth, called
attention to three specimens of sandstone and limestone containing
specimens of some species of Hyolithes, which Prof. Lapworth had
found in the higher part of the Cambrian quartzite at Nuneaton, in
Warwickshire. Three of the species recognized (Hyolithes princeps,
Coleoloides typicalis, and Stenotheca rugosa) occur in the Olenellus-
beds of America, and three others, Torrellella laevigata, Hyolithes
(Orthotheca) corneolus, and H. de G'eert, in the same rocks in Europe.
The Olenellus-zone of Nuneaton occurs above the main mass of the
quartzite and below the Stockingford Shales, in a series of rocks
only recently exposed by quarrying.

The following communications were read :—

1. ‘On the Speeton Series in Yorkshire and Lincolnshire.’ By
G. W. Lamplugh, Esq., F.G.S.

2. *On some Podophthalmatous Crustacea from the Cretaceous
Formation of Vancouver and Queen Charlotte Islands.’ By Henry
Woodward, LL.D., F.R.S., P.G.S.

3. ‘On a fossil Octopus, Calais Newboldi (J. de C. Sby., MS.),
from the Cretaceous of the Lebanon.’ By Henry Woodward, LL.D.,
FERS. P.G.8:

4. ‘On Transported Boulder Clay.’ By the Rev. Edwin Hill,
M.A:, F.G.S.

The following specimens were exhibited :—

Fossils from the Speeton Series in Yorkshire and Lincolnshire, with
a microscope-section of a so-called ‘derivative pebble’ from the
nodular bed at the base of the Spilsby Sandstone, exhibited by
G. W. Lamplugh, Esq., F.G.S., in illustration of his paper.

Specimens of Callianassa Whiteavesii, Homalopsis Richardsoni,
and Plagiclophus vancowverensis, from the Geological Survey of
Canada, with two of the latter from the Society’s Museum, exhibited
by Dr. Henry Woodward, F.R.S., P.G.S., in illustration of his first

aper.

Z A specimen of Calais Newboldii, from the Cretaceous of the
Lebanon, from the Society's Museum, exhibited by Dr. Henry
Woodward, F.R.S., P.G.S., in illustration of his second paper.

Specimens of Myolithes-sandstone (Olenellus-zone) recently dis-
covered at Nuneaton, exhibited by Prof. Charles Lapworth, LL.D.,
F.RBS., F.G.8.

Vol. 52.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Vii

February 5th, 1896.
Dr. Henry Woopwarp, F.R.S., President, in the Chair.

Colonel Charles Kendal Bushe, Bramhope, Blackheath Road, Old
Charlton, Kent, and John Turner, Esq., Donisthorpe, Ashby-de-la-
Zouch, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On the Morte Slates and Associated Beds in North Devon and
‘West Somerset.—Part I.’ By Henry Hicks, M.D., F.R.S., F.G.S.

2. * Kvidences of Glacial Action in Australia in Permo-Carboni-
ferous Time.’ By Prof. T. W. Edgeworth David, B.A., F.G.S.

The following specimens, maps, and photographs were exhibited :—

Fossils exhibited by Dr. Henry Hicks, F.R.S., F.G.S., in illus-
tration of his paper.

Fossils from North Devon, exhibited by the Rev. H. H. Win-
wood, M.A., F.G.S.; and specimens of Graptolites, exhibited by
John Hopkinson, Esq., F.G.S., in illustration of Dr. Hicks’s paper.

Glaciated boulders, and photographs of the same, exhibited by
Prof. T. W. Edgeworth David, B.A., F.G.8., in illustration of his
paper.

Fragment of Boulder from the Carboniferous Boulder Bed of
the Panjab Salt-Range, collected by Dr. H. Warth, exhibited by
Dr. W. T. Blanford, F.R.S., Treas.G.S.

Australian auriferous specimens, exhibited by the President on
behalf of J. C. F. Johnson, Esq., of South Australia.

Sheets 20, 21, 26, and 27 of the 1l-inch Map with MS. geo-
logical work by W. A. E. Ussher, Esq., F.G.S., exhibited by the
Director-General of H.M. Geological Survey.

Photograph of the late Martin Simpson, presented by Arthur
‘Smith Woodward, Esq., F.L.S., F.G.S.

b2

ANNUAL GENERAL MEETING,

February 21st, 1896.

Dr. Henry Woopwarp, F.R.S., President, in the Chair.

REPORT OF THE CounciIL FoR 1895.

Tue continued prosperity of the Society from the financial point of
view must again form a subject of congratulation, and the Council
have the additional pleasure of pointing out that the decrease which
had been noticeable in the number of Fellows, mentioned in the
three previous Annual Reports, has now been all but arrested, the
actual decrease in the total number of Fellows announced this year
being only 1, as compared with 11 in 1894, and 46 in 1893.

During 1895 the total number of Fellows elected into the Society
was 43, of whom 32 paid their fees before the end of that year.
Moreover, fees were received from 12 previously elected Fellows,
and thus the total accession of new Fellows amounts to 44 during
the twelvemonth.

There was, on the other hand, a total loss of 45 Fellows during:
the year 1895—25 by death, 10 by resignation, and 10 removed from
the list because of non-payment of their Annual Contributions.

The actual decrease in the total number of Fellows is, therefore,
as above stated, 1.

Of the 25 Fellows deceased, 9 were Compounders, 10 were Con-
tributing Fellows, and 6 were non-Contributing Fellows.

On the other hand, 9 Fellows compounded during the past year
for their Annual Contributions. The total acdession of Contri-
buting Fellows is thus seen to be 35, and the total loss being 30
(10+10+10), the increase in the number of Contributing Fellows
is 5.

At the end of 1894 the Council reported one vacancy in the List
of Foreign Correspondents. In 1895, 4 Foreign Members and
1 Foreign Correspondent died. The vacancies which thus arose
were partly filled by the election of 3 Foreign Members and 3 Foreign

Vol. 52.] ANNUAL REPORT. , ix

Correspondents during the past year; but at the end of 1895 there
was still 1 vacancy in the List of Foreign Members, and 2 vacancies
in the List of Foreign Correspondents.

The total number of Fellows, Foreign Members, and Foreign
Correspondents, which at the end of 1894 was 1321, stood at 1318
on December 31st, 1895.

The Society’s Income and Expenditure in the year under review
may be summarized as follows :—

The total Receipts amounted to £3249 13s. 4d., being £666 7s.
more than the estimated Income for 1895. On the other hand,
the total Expenditure during that year amounted to £2398 ds. 11d.,
being less by £181 10s. 1d. than the estimated Expenditure for
1895. The actual excess of Receipts over current Expenditure in
that year was £492 18s. 4d.

It should be mentioned here that the following Re-investment of
a portion of the Society's Funds was made in 1895. Of 22 per
Cent. Consolidated Stock £3769 2s. 6d. was sold at 1048, and the
sum thus produced was applied to the purchase of £2000 India
3 per Cent. Stock at 104, and £1295 Midland Railway 4 per Cent.
Perpetual Preference Stock at 1414. Moreover, in the various
Trust Funds held by the Society, the following Re-investments were
made. On account of the Wollaston Fund £1084 Is. 1d. 22 per
Cent. Consolidated Stock was sold at 1048, and the sum thus
obtained was applied to the purchase of £1073 Hampshire County
3 per Cent. Stock at £1053. Similarly, the £500 22 per Cent.
Consolidated Stock belonging to the Barlow-Jameson Fund was
sold at £1043, while £468 Great Northern Railway 3 per Cent.
Debenture Stock was purchased in lieu of it at £1103; also
£209 8s. 6d. 22 per Cent. Consolidated Stock forming the Bigsby
Fund was sold at £1043, and the sum thus obtained was applied to
the purchase of £210 Cardiff Corporation 3 per Cent. Stock at 1044.
It need hardly be pointed out that the object of these Re-investments
was to obtain a larger Income while still holding perfectly sound
securities.

The Council have pleasure in announcing the completion of
Volume LI. of the Society’s Quarterly Journal and the commence-
ment of Volume LIT.

The first number of the new Record of Geological Literature
added to the Society’s Library was issued concurrently with the
May number of the Journal in 1895, and its usefulness seems to
have been very generally recognized. As was stated in the previous
Report of the Council, now and in future this publication will
appear concurrently with the February number of the Society’s
Quarterly Journal.

The compilation of the Index to the first Fifty Volumes of the
Quarterly Journal is now all but complete, Vol. 48 having been
reached, and the manuscript will very soon be placed in the hands
of the printers. It is confidently hoped that the whole of the Index
will be placed in the Fellows’ hands in the course of the present
year.

x PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896,

The question as to how far it is desirable for the Society to
maintain a Museum has, for a considerable time, been under the
earnest consideration of the Council, and it was felt that if the
Society decided that the maintenance of the collections in their
present condition was undesirable, the British Museum (Natural
History) would probably be the most satisfactory receptacle for
them. The Council have accordingly been in communication with
the Trustees of the British Museum, and find that they would be
willing to receive such portions of the collections as the Society
may wish to transfer to them on the following conditions :—The
specimens which are types and those which illustrate papers read
before the Society are to be preserved and maintained apart, and the
Trustees will reimburse the Society for the expenses in connexion
with the transference up to a sum not exceeding £300.

The provisional assent of the Trustees of the British Museum to
these conditions was formally given at their meeting of January 25th,
1896; and as the ultimate decision regarding the proposed trans-
ference must rest with the general body of Fellows, the subject will
no doubt be brought forward at a Special General Meeting at an
early date.

Meanwhile, a short summary of the steps taken in connexion
with the Museum may here be brought to the notice of the
Fellows.

On April 22nd, 1891, the attention of the Council having been
drawn by the Rey. J. F. Blake to the unsatisfactory state of the
Society’s Museum, as regards defective labelling, incomplete regis-
tration, bad conditions of location and preservation of specimens,
etc., a Special Committee was appointed to examine into the
question. On May 27th, that Committee finally reported to the effect
that it was desirable to select and register all specimens illustrating
the history of the Society (including type-specimens), and called
attention to collections of simple minerals, typical foreign rocks,
and recent shells, with a view to their possible removal. This
report was adopted by the Council the same day (May 27th, 1891),
and Mr. C. Davies Sherborn, F.G.S., was afterwards requested to
undertake the work of registration of important specimens thus
selected. This task Mr. Sherborn proceeded with as rapidly as the
state of his health would allow. He completed it, so far as the
English Collections were concerned, and, by the end of 1895, had
gone through part of the Foreign Collection, having, in all, examined
about three-fifths of the Society’s Museum.

An epitome of the contents of the Museum and a statement of
the work accomplished were laid before a Special Committee on
October 29th, 1895, and that Committee reported on November 6th
to the Council, recommending the transference of the Museum to the
National Collections on the conditions already cited, reserving to
the Society such specimens of historical interest or of an ornamental
nature as are displayed on the walls of the Society’s Apartments.
This Report was, after careful consideration, adopted by the Council
on November 20th, 1895.

Vol. 52.] ANNUAL REPORT. xi

If the Society decide upon the transference, the space, when
vacated by the collections, would become available for the Library ;
and the Council must point out that the provision of further accom-
modation for books will soon become a matter of urgent necessity.
As it is, the proper and commodious arrangement of many of the
serial publications is hampered for want of room.

The Council are of opinion that the Redecoration of the Society’s
Apartments and the introduction of the Electric Light constitute
improvements which it is desirable to carry out at an early date.
The total cost would probably amount to between £700 and £800,
and the Balance Sheet placed in the hands of the Fellows shows
that the necessary expenditure could be almost entirely provided
for from the surplus that has accrued during the last few years.
At the same time, the expense of only a portion of the necessary
Redecoration is included with that of the Electric Installation in
the Estimates for the current year, so that the whole expenditure
may be spread over a period of not less than two years.

The following awards of Medals and Funds have been made by
the Council :—

The Wollaston Medal is awarded to Prof. Eduard Suess, For.
Memb.G.8., of Vienna, in recognition of his long and brilliant
services to the cause of Geological Science.

The Murchison Medal, with a sum of Ten Guineas, is awarded to
Mr. T. Mellard Reade, F.G.S., in recognition of the value of his
work on mountain-making, Glacial drifts, and other branches of
post-Pliocene geology.

The Lyell Medal, with a sum of Twenty-five Pounds, is awarded
to Mr. Arthur Smith Woodward, F.G.S., in recognition of the value
of his work on Fossil Vertebrata, and especially in Paleichthyology.

The Balance of the Proceeds of the Wollaston Fund (together
with a sum of Six Pounds Fifteen Shillings transferred from the
Barlow-Jameson Fund, in order to supplement an accidental
deficiency in the Wollaston Fund incidental to the aforementioned
change of investments) is awarded to Mr. Alfred Harker, in testi-
mony of appreciation of his petrological work, and with the view of
assisting him in further research.

The Balance of the Proceeds of the Murchison Geological Fund
is awarded to Mr. Philip Lake, F.G.S., as a recognition of the value
of his paleontological and other researches amongst the older rocks,
and to aid him in the prosecution of these studies.

A moiety of the Balance of the Proceeds of the Lyell Geological
Fund is awarded to Dr. W. F. Hume, F.G.S., for his researches on
Cretaceous rocks and on the Loess formation, and also to assist him
in further work.

The other moiety of the Balance of the Proceeds of the Lyell
Geological Fund is awarded to Mr. Charles W. Andrews, F.G.S., in
recognition of the value of his work on Fossil Birds and Reptilia,
and to assist him in the prosecution of further investigations.

An award of Twenty Pounds is made from the Barlow-Jameson
Fund to Mr. Joseph Wright, F.G.S., in token of appreciation of his

xil PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896,

work on the microfauna of the Irish Chalk, and with the view of
aiding him in further research.

Another award of Twenty Pounds from the Barlow- Jameson Fund
is made to Mr. John Storrie, of Cardiff, as a mark of appreciation of
his original work on the geology of the neighbourhood of that town,
and to assist him in carrying out further useful investigations.

The Council cannot conclude this Report without referring to the
loss which the Society has sustained in the person of its valued
and most efficient Assistant-Clerk, Mr. Francis EK. Brown, who died
suddenly in the beginning of August last. He had served the
Society for upwards of nine years, and had earned the esteem and
confidence, not only of the Officers and Council, but of all those
among the Fellows who came into contact with him.

Report oF THE LisraRy CommittEr ror 1895.

Your Committee have pleasure in stating that very many valuable
additions have been made to the Library during the past year, both
by Donation and Purchase. It is, in a large measure, due to the
liberality of the Fellows, of various public bodies, and of kindred
societies, that the donations far exceed in amount the purchases:
this will be readily deduced from the statistics embodied in the
present Report.

By Donation the Library has received about 85 Volumes of
separately published works, 377 Pamphlets and detached Parts of
works, 172 Volumes and 207 detached Parts of serial publications
(Transactions, Memoirs, Proceedings, etc.), and 16 Volumes of
Newspapers. The total addition to the Library by Donation
amounts therefore to 273 Volumes, 377 Pamphlets, and 207 detached
Parts. Moreover, 116 Sheets of Maps have been presented to the
Society during the past year.

Your Committee desire to call special attention to the magnificent
Geologic Atlas of the United States, all the sheets of which (so far
as published) have been presented by the Government of that
country. Nor have other public bodies in the United States failed
in their wonted liberality: among others, the New York, Minnesota
Missouri, and Alabama State Geological Surveys have enriched this
Society’s Library with many handsome volumes of memoirs, plates,
and maps. Three important volumes of the Beitrige zur geologischen
Karte der Schweiz have been received from the Swiss Geological
Commission during the past year, as also a large number of maps
from the Geological Survey of the kingdom of Saxony. No less than
twenty-four sheets of maps have -been presented by the Geological
Survey of Canada, and six volumes of memoirs by the Comité
Géologique of St. Petersburg. From H.M. Geological Survey have
come some important memoirs and several sheets of the 1-inch map
(both drift and solid geology) and sheets of horizontal and vertical
sections; while from H.M. Treasury the Society has received the
volume embracing the Summary of the Scientific Results of the

ee ee —— ae =

Vol. se. | ANNUAL REPORT. xili

‘Challenger’ Expedition. The first instalment of the International
Geological Map of Europe (including seven sheets) has also been
received, and from the Geological Survey of India has come the
2nd edition of the small-scale geological map of that Empire.

A yaluable collection of geological papers, many of which are
now out of print, has been presented by Prof. G. J. Allman, F.R.S.
Monsieur P. de Loriol-Lefort, For.Corr.G.S., of Geneva, Senor Don
Florentino Ameghino, of Buenos Ayres, and the Marchese A. de
Gregorio, of Palermo, have respectively enriched the Library with
sets of their own papers and memoirs; and the Royal University
of Upsala, besides presenting the ‘ Meddelanden’ published by its
Geological Institute, has sent through its Librarian a considerable
number of separately printed papers by Scandinavian geologists.

The Society’s collection of portraits of historical interest has been
enriched by the presentation of a drawing in crayons of Leonard
Horner, given by Mrs. Katherine Lyell, and a photograph of the
well-known Yorkshire geologist, Martin Simpson, given by Mr. Arthur
Smith Woodward. Moreover, a portrait in oils of the late Dean
Buckland has been purchased from his daughter, Mrs. Gordon.

The Books, Maps, and Portraits enumerated above were the gift

of 191 Personal Donors, 62 Public Bodies, and 200 Societies and
Editors of Periodicals.
- The Purchases made on the recommendation of the Standing
Library Committee amounted to 36 Volumes and 15 Parts of sepa-
rately published works, 25 Volumes and 20 Parts of works published
serially, and 10 Sheets of Maps.

The total amount expended upon the Library during the year
1895 is as follows :—

bo sd

Books, Periodicals, etc., purchased ........ 68°" 7 3
Binding of Books and Mounting of Maps.... 99 1 10
Part cost of preparing Map Catalogue...... 3 11-3
h(i. 0 26

Your Committee have pleasure in announcing that the manuscript
Card Catalogue of the Geological Maps and Sections in the Library
is now practically completed.

As the question of the Museum has been dealt with by a Special
Committee who have reported to the Council, all that need be said
in this place is that the sum set apart in the Estimates, for regis-
tering and cataloguing specimens, namely £50, has been expended
during the past year, and constitutes the sole item of expenditure
incurred in connexion with the Museum in 1895.

XIV PROCEEDINGS OF THE GEOLOGICAL society. [May 1806,

The following Lists contain the Names of Government Depart-
ments, Public Bodies, Societies, Editors, and Personal Donors, from
whom Donations to the Library have been received during the
past year :—

I. GovERNMENT DEPARTMENTS AND OTHER Pustic Boprs&s.

Alabama.—Geological Survey of Alabama. Montgomery (Ala.).

American Museum of Natural History. New York.

Austria.—Kaiserlich-K6nigliche Geologische Reichsanstalt. Vienna.

—. Kaiserlich-Kénigliches Naturhistorisches Hofmuseum. Vienna.

Baden.—Grossherzogliches Ministerium des Innern. Geologische Landesanstalt.
Heidelberg.

Bavaria.—K@6niglich Bayerisches Oberbergamt. Munich.

California—State Mining Bureau. San Francisco.

Canada.—Geological & Natural History Survey. Ottawa.

Finland.—Finlands Geologiska Undersékning. Helsingfors.

France.—Dépét dela Marine. Paris.

——. M*inistére des Travaux Publics. Paris.

——. Muséum d’Histoire Naturelle. Paris.

Service de la Carte Géologique. Paris.

Great Britain——Army Medical Department. London.

British Museum (Natural History). London.

—. Geological Survey. London.

—. Home Office. London.

—. Ordnance Survey.

—. The Lords Commissioners of Her Majesty’s Treasury. London.

Hesse.—Grossherzogliches Ministerium des Innern. Geologische Landesanstalt.
Darmstadt.

Holland.—Departement van Kolonien. The Hague.

Hungary.—K6nigliche Ungarische Geologische Anstalt. Budapest.

Illinois.—State Museum of Natural History. Springfield (IIL).

India.—Geological Survey. Calcutta.

Italy.— Reale Comitato Geolégico d’Italia. Rome.

Japan.—Geological Survey. Tokio.

La Plata Museum. La Plata.

Mexico.—Comision Geoldédgica de Mexico. Mexico.

Minnesota.—Geological and Natural History Survey. Minneapolis.

Missouri.—Geological Survey of Missouri. Jefferson City (Mo.).

New South Wales.—Agent-General for, London.

—. Australian Museum. Sydney.

——. Department of Lands. Sydney.

——. Department of Mines. Sydney.

. Geological Survey. Sydney.

New York State Library. Albany.

New York State Museum. Albany.

Norway.—Norges Geologiska Undersékning. Christiania.

Nova Scotia.—Department of Mines. Halifax (N.S.).

Perak Government. Taiping.

Portugal.—Commissio Geologica de Portugal. Lisbon.

Prussia.—K6nigliche Preussische Geologische Landesanstalt. Berlin.

Kénigliches Ministerium fiir Handel und Gewerbe. Berlin.

Queensland.—Geological Survey. Brisbane.

Russia.—Comité Géologique. St. Petersburg. :

Saxony.—Geologische Landesuntersuchung des Kénigreichs Sachsen. Leipzig.

—. KoOnigliches Finanz-Ministerium. Leipzig.

South Australia—The Agent-General for, London.

Spain.—Comision del Mapa Geoldégico. Madrid.

Sweden.—Sveriges Geologiska Undersékning. Stockholm.

Switzerland.—Commission der Geologischen Karte. Berne.

United States Bureau of Ethnology. Washington.

United States Department of the Interior. Washington.

United States ‘ Field’ Columbian Museum. Chicago.

United States Geological Survey. Washington.

United States National Museum. Washington.

7"

Vol. 52. | ANNUAL REPORT. XV

United States Treasury (Mint) Department. Washington.
Victoria.—Department of Mines. Melbourne.
Washington (D. C.).—Smithsonian Institution.

Western Australia——Department of Mines. Perth.

—. Geological Survey. Perth.

—. The Agent-General for, London.

II. Soctetres anp Eprtors.

Adelaide.——Royal Society of South Australia.

Alnwick.—Berwickshire Naturalists’ Club.

Bahia.—Instituto Geographico e Historico.

Barnsley (Newcastle-upon-Tyne). —Midland Institute of Mining, Civil and
Mechanical Engineers.

Basel.—Schweizerische Naturforschende Gesellschaft.

Bath Natural History and Antiquarian Field Club.

Belfast Natural History and Philosophical Society.

Belgrade.—Annales Géologiques de la Péninsule Balkanique.

Berkeley (Cal.).—Department of Geology, University of California.

Berlin.—Deutsche Geologische Gesellschaft.

Gesellschaft Naturforschender Freunde.

—. Konigliche Preussische Akademie der Wissenschaften.

—. Zeitschrift fiir praktische Geologie.

foe eee Schweizerische Gesellschaft fiir die gesammten Naturwissen-
schaften.

—. Naturforschende Gesellschaft.

Birmingham.—Mason College.

—. Philosophical Society.

Bombay.—Poona College of Science.

Boston (Mass.).—American Academy of Arts and Sciences.

Boston Society of Natural History.

Brussels.—Académie Royale des Sciences, des Lettres et des Beaux-Arts de
Belgique.

—. Société Belge de Géologie, de Paléontologie et d’Hydrologie.

—. Société Malacologique de Belgique.

Budapest.—Fdldtani Kozlony (Geological Magazine).

Magyar Foéldtani Tarsulat.

Buenos Aires.—Instituto Geografico Argentino.

—. Sociedad Cientifica Argentina.

Caen.—Société Linnéenne de Normandie.

Calcutta.—Indian Engineering.

—. Asiatic Society of Bengal.

Cambridge.— University Library Syndicate.

Cambridge (Mass.).—Museum of Comparative Zoology, at Harvard College.

Cape Town.—South African Philosophical Society.

Cardiff.—South Wales Institute of Engineers.

Chicago.—Journal of Geology.

Christiania.— Videnskabernes Selskab.

Cincinnati Society of Natural History.

Colombo.—Ceylon Branch of the Royal Asiatic Society.

Colorado Springs (Col.).—Colorado College Scientific Society.

Copenhagen.— Dansk Geologisk Forening.

Kongelige Danske Videnskabernes Selskab.

Cérdoba (Argentine Republic).—Academia Nacional de Ciencias.

Cork.—Queen’s College.

Cracow.—Académie des Sciences.

Akademja Umiejetosci.

Darmstadt.—Verein fiir Erdkunde.

Dijon.—Académie des Sciences, Arts et Belles-Lettres.

Dorchester.—Dorset Natural History and Antiquarian Field Club.

Dorpat.—Naturforscher Gesellschaft bei der Universitat Jurjew.

Douglas.—Isle of Man Natural History and Antiquarian Society.

Dresden.—Naturwissenschaftliche Gesellschaft ‘ Isis.’

Dublin.—Royal Irish Academy.

Edinburgh.—Royal Scottish Geographical Society.

——. Royal Society.

PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896.

Ekaterinburg.—Société Ouralienne d’Amateurs des Sciences Naturelles.

Falmouth.—Royal Cornwall Polytechnic Society.

Frankfurt a. M.—Senckenbergische Naturforschende Gesellschaft.

Glasgow.—‘ Mitchell’ Library.

Giessen.—Oberhessische Gesellschaft fiir Natur- und Heilkunde.

Glasgow.—Philosophical Society.

Gloucester.—Cotteswold Naturalists’ Field-Club.

Gratz.—Naturwissenschaftlicher Verein fiir Steiermark,

Haarlem.—Société Hollandaise des Sciences.

Halifax.—Yorkshire Geological and Polytechnic Society.

Halifax (N. 8.)—Nova Scotian Institute of Science.

Halle.—Kaiserliche Leopoldinisch-Carolinische Deutsche Akademie der Natur-
forscher.

Hamilton (Canada).—Hamilton Association.

Hanau.—Wetterauische Gesellschaft fiir die gesammte Naturkunde.

Havre.—Société Géologique de Normandie.

Hertford.—Hertfordshire Natural History Society.

Houghton (Mich.).—Michigan Mining School.

Hull.—Geological Society.

Ithaca (N. Y.).—Cornell University.

Kiev.—Société des Naturalistes.

Kingston (Canada).—Queen’s College.

Lausanne.—Société Géologique Suisse.

——. Société Vaudoise des Sciences Naturelles.

Leeds.—Geological Association.

Philosophical Society.

Leicester Literary and Philosophical Society.

Leipzig.—Naturwissenschaftlicher Verein fiir Sachsen und Thiiringen.

Zeitschrift fiir Krystallographie und Mineralogie.

Zeitschrift fir Naturwissenschaften.

Liége.—Société Géologique de Belgique.

Société Royale des Sciences.

Lille.-—Société Géologique du Nord.

Lisbon.—Academia Real das Sciencias.

Sociedade de Geographia.

Liverpool.—Geological Association.

Geological Society.

Naturalists’ Field-Club.

ondon.—Academy.

Atheneum.

British Association for the Advancement of Science.

Chemical News.

Chemical Society.

City of London College.

Colliery Guardian.

East India Association.

Geological Magazine.

Geologists’ Association.

Institution of Civil Engineers.

India Rubber, Gutta Percha, and Telegraph Works Co., Lim.

Iron and Steel Institute.

Tron and Steel Trades’ Journal.

Knowledge.

Linnean Society.

London, Edinburgh, and Dublin Philosophical Magazine.

Mineralogical Society.

Nature.

Paleontographical Society.

Physical Society.

Royal Agricultural Society.

Royal Astronomical Society.

Royal College of Surgeons.

Royal Geographical Society.

Royal Institution.

Royal Meteorological Society.

Royal Microscopical Society.

Royal Photographic Society of Great Britain.

Royal Society.

|

PEPECREELEPE PHS SG IER IHBER

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Vol. 52.| ANNUAL REPORT. Xvi

London.—Sanitary Institute.

Society of Arts.

Society of Biblical Archeology.

Society of Public Analysts.

University College.

Victoria Institute.

Zoological Society.

Madison (Wis.).—University of Wisconsin.

Madrid.—Real Academia de Ciencias Exactes, Fisicas y Naturales.

Manchester Geological Society.

——. Literary and Philosophical Society.

Melbourne.—Royal Society of Victeria.

Mexico.—Sociedad Mexicana de Historia Natural.

Milan.—Giornale di Mineralogia.

Reale Instituto Lombardo di Scienze e Lettere.

——. Societa Italiana di Scienze Naturali.

Minneapolis——Minnesota Academy or Natural Sciences.

Montreal.—Natural History Society.

Moscow.—Société Impériale des Naturalistes.

Munich.—Konigliche Bayerische Akademie der Wissenschation!

Newcastle-upon-Tyne. North of England Institute of Mining and Mechanical
Engineers.

New Haven (Conn.).—American Journal of Science.

—. Connecticut Academy of Arts and Sciences.

New York.—Academy of Sciences.

——. American Institute of Mining Engineers.

Northampton.—Northamptonshire Natural History Society.

Oporto.—Sociedade Carlos Ribeiro.

Ottawa.—Royal Society of Canada.

Padua.—Reale Accademia di Scienze, Lettere ed Arti.

Palermo.—Annales de Géologie et de Paléontologie.

—. Reale Accademia di Scienze, Lettere ed Arti.

Paris.—Académie des Sciences.

Annuaire Géologique Universel.

——. Revue Scientifique.

—. Société Frangaise de Minéralogie.

Société Géologique de France.

Penzance.—Royal Geological Society of Cornwall.

Philadelphia.—Academy of Natural Sciences.

——. American Philosophical Society.

——. Wagener Free Institute of Science.

Pisa.—Reale Universita.

—. Societa Toscana di Scienze Naturali.

Plymouth.—Devonshire Association for the Advancement of Science.

Institution, and Devon and Cornwall Natural History Society.

Port-of-Spain. —Victoria Institute of Trinidad.

Rochester (N. Y.).—Geological Society of America.

Rome.—Reale Accademia dei Lincei.

—. Societa Geologica Italiana.

Rugby School N atural History Society.

St. John (N. B.).—Natural History Society.

St. Petersburg.—Académie Impériale des Sciences.

—. Russische Kaiserliche Mineralogische Gesellschaft.

Santiago.—Deutscher Wissenschaftlicher Verein.

—. Sociedad Nacional de Mineria.

Société Scientifique du Chili.

Scranton (Pa.).—Colliery Engineer.

Stockholm.—Geologiska Foérening.

—. Kongliga Svenska Vetenskaps Akademi.

Stuttgart. —Neues Jahrbuch fiir Mineralogie, Geologie und Paliontologie.

——, Verein fiir Vaterlandische Naturkunde in Wiirttemberg.

Sydney.—Linnean Society of New South Wales.

—. Royal Society of New South Wales.

Tokyo.—College of Science, Imperial University.

—. Imperial University.

——. Seismological Journal of Japan.

Toulouse.—Société d’Histoire Naturelle.

Truro.— Royal Institution of Cornwall.

HW

XVIli PROCEEDINGS OF THE GEOLOGICAL sociETy. [May 1896,

Tufts College, Massachusetts.

Turin.—Reale Accademia delle Scienze.

Upsala Universitet.

Universitets Mineralogisk-Geologiska Institution.
Vienna.—Berg- und Hiittenmannisches Jahrbuch.

——. Kaiserliche Akademie der Wissenschaften.

——. Kaiserlich-konigliche Zoologisch-botanische Gesellschaft.
——. Mniuneralogische und Petrographische Mittheilungen.
Wellington (N.Z.).—New Zealand Institute.
Wiesbaden.—Nassauischer Verein fiir Naturkunde.
York.—Natural History Journal.

——. Yorkshire Philosophical Society.

II]. Pxrsonat Donors.

Agassiz, A. Egger, J. G. Johnston-Lavis, H. J.
Allman, G. J. Exton, H. Jones, T. R
Ameghino, F. Jordan, H. K.
Ami, H. M. Faggiotto, A.

Fairchild, H. L. Karrer, F.
Barlow, W. Fayol, H. Kayser, E.
Barrois, C. Felix, J. Kendall, P. F.
Bascom, F. Fisher, O. Keyes, C. R.
Bauerman, H. Floyer, EH. A. Kirkby, J. W.
Bayley, W. S. Fornasini, C. Klement, C.
Beecher, C. E. Foster, C. Le Neve. Koenen, A. von.
Bell, D. Fouqué, F. Kossmat, F.
Bennett, J. F. Fowler, T. W. Kuntze, O.
Bittner, A. Fox, Howard. Kurtz, F.
Blake, W. P. Fritsch, A.
Bolton, H. Leighton, T.
Bonney, T. G. Gagel, C. Liversidge, A.
Botte, U. Geikie, Sir A. Loeffelholz von Colberg,
Brodie, P. B. Geikie, J. C.
Brégger, W. C. Gilbert, G. K. Loriol, P. de.
Brongniart, C. Gilpin, E., Jun. Lyell, Mrs. Katherine.
Brown, J. A. Gosselet, J. Lyman, B. S.
Brown, N. Gregorio, Marquis
Brown, H. Y. L. Antonio de. McHenry, A.
Bukowski, G. von. Gresley, W. S. Mackinnon, A. K.

Mallet, F. R.

Carey, L. Hall, Marshall. Mansel-Pleydell, J. C.
Cayeux, L. Hanks, H. G. Manson, M.
Chalmers, J. A. Hargreaves, T. 8S. Marsh, O. C.
Chamberlin, T. C. Harker, A. Matthews, W.
Claypole, E. W. Harle, E. Meli, R.
Cole, E. M. Harrison, W. J. Merrill, G. P.
Collins, J. H. Hatch, F. H. Mill, H. R.
Cooke, S. Heim, A. Milne, J.
Cope, E. D. Heimbach, H. Monckton, H. W.
Conwentz, H. Hennig, A. Moody, T. P.
Crane, A. Jebliee Morton, G. H.
Crawford, J. J. Hill, R. T. Mrazec, L.
Credner, H. Hills, R. C.

Hinde, G. J. Nathorst, A. G.
Dames, W. Hobbs, W. H. Newton, E. T.
Davies, T. W. Holzapfel, E. Newton, R. B.
Dawson, Sir J. William. Hopkinson, J. Nicholas, W.
Delebecque, A. Hoskold, H. D. Nordenskjéld, 0. G.
Destinez, P. Hoyle, W. E.
Dollfus, G. F. Hull, B. Platt, S. S.
Doyle, P. Hume, W. F. Pompeckj, J. F.
Draper, D. Power, F. D. |
Dubois, E. Jack, R. L. Preller, C. S. Du Riche. |
Dupare, L. James, J. F. Prestwich, Sir J. !

Vol. 52.]

Ramsay, A.
Ransome, F. L.
Reade, T. Mellard.
Reid, C.

Reyer, E.
Renevier, E.
Reusch, Hans.

Richards, Sir G. H.

Richardson, R.
Ritter, E.
Rosenbusch, H.

Sandberger, F. von.

Sauvage, H. E.
Scudder, S. H.
Seeley, H. G.
Shillingford, F. A.
Sherborn, C. D.
Shipman, J.
Sjogren, H.
Smith, E. A.

ANNUAL REPORT.

Spencer, J. W.
Spezia, G.

Stanley, W. F.
Stefanescu, G.
Stevenson, W.
Storrie, J.
Story-Maskelyne, N.
Strahan, A.

Suess, E.

Tate, T.
Thugutt, S. J.
Trabucco, G.
Tschermak, G.
Upham, W.
Vaughan, T. W.

Wahner, F.
Walford, E. A.

xix

Wardell, F. N.
Walther, J.
Watts, W. W.
Wehrli, L.
Whidborne, G. F.
Whitaker, W.
Wilson, E.
Wiman, C.
Winchell, N. H.
Winslow, A.
Winwood, H. H.
Woodward, A. S.
Woodward, H.
Woodward, H. B.
Woodward, H. P.
Wray, L., Jun.

Zeiller, R.
Zujovic, J. M.

Rater, |

xx PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896,

CoMPARATIVE STATEMENT OF THE NUMBER OF THE SOCIETY AT THE
CLOSE OF THE YEARS 1894 anp 1895.

Dee. 31st, 1894. Dec. 31st, 1895.

Compoumders {26 ak we ece BOD hi cihin cote 305
Contributing Fellows...... BG2NG ieee 867
Non-contributing Fellows .. Con Ee Beer 69

1242 1241
Foreign Members ........ 10 Mn oso 39
Foreign Correspondents... . ONT Lae 38 .

1321 1318 |

Comparative Statement explanatory of the Alterations in the Number
of Fellows, Foreign Members, and Foreign Correspondents at the
close of the years 1894 and 1895.

Number of Compounders, Contributing and Non- 1949
contributing Fellows, December 31st, 1894 ..
Add Fellows elected during former year and paid } 12
1 OG. EN Sie sas. 5) IE es 8 tere ee
Add Fellows elected and paidin 1895 ........ 32
1286
Deduct Compounders deceased.............4.. 9
Contributing Fellows deceased .......... 10
Non-contributing Fellows deceased ...... 6
Contributing Fellows resigned .......... 10
Contributing Fellows removed .......... 10
— 45
. . aaa
Number of Foreign Members and Foreign } 79
Correspondents, December 31st, 1894 ....
Deduct Foreign Members deceased ........ 4
Foreign Correspondent deceased .... 1
Foreign Correspondents elected
Foreign Members 75. ........ }
_ 8
el
Add Foreign Members elected .............. 3
Foreign Correspondents elected ........ 3
— 77 |
1318 |

Vol. 52.] ANNUAL REPORT.

DrcEAsED FELLOWS.

Compounders (9).

Ball, V., Esq. Lawrence, P. H., Esq.
Browne, Ven. Archdeacon. Mitchell, J., Esq.
Carter, R., Esq. Slatter, T. J., Esq.
Cline, Dr. G. W. Tyler, C., Esq.

Johnson, F., Esq.

Resident and other Contributing Fellows (10).

Bunbury, Sir E. H. Hulke, J. W., Esq.
Carter, J., Esq. Huxley, Rt. Hon. T. H.
Chance, E. J., Esq. Milnes, W.S., Esq.
Copland-Crawford, Lt.-Gen.R.F. | Williams, J. E., Esq.
Hosking, G. F., Esq. Wunsch, H. A., Esq.

Non-contributing Fellows (6).

Babington, Prof. C. C. Lester, Rev. Lester.
Duke, Rev. E.

Fitch, R., Esq.

Tayler, J. W., Esq.

Foreign Members (4). |
Dana, Prof. J. D. Riitimeyer, Prof. L.

Lovén, Prof. Sven. Saporta, Marquis G. de.

Foreign Correspondent (1).
Castillo, Don Antonio del.

VOL. LIT. ¢

Mantell, W. B. D., Esq.

Xxi

Xxil PROCEEDINGS OF THE GEOLOGICAL socrETy. [May 1896,

Freitows Restenzp (10).

Baldwin, A. E., Esq. Routh, C. 8., Esq.
Isaac, T. W. P., Esq. Sherwood, W., Esq.
Johnson, M. H., Esq. Whitmell, C. T., Esq.
King, Dr. W. | Willett, H., Esq.
Plowright, H. J., Esq. Winter, T., Esq.

Frettows Removen (10).

Ballard, Rev. F. Milles, R. S., Esq.
Browne, C., Esq. Muir, E., Esq.

Burns, D., Esq. Ratnavelacharia, M., Esq.
Gilpin, E., Esq. Rowlandson, T., Esq.
Maude, Captain F. N. Wilson-Moore, C., Esq.

The following Personages were elected from the Lust of Foreign Cor-
respondents to fill the vacancies in the Inst of Foreign Members
during the year 1895 :—

Monsieur F. Schmidt, of St. Petersburg.
Professor W. Dames, of Berlin.
Professor G. K. Gilbert, of Washington, U.S.A.

The following Personages were elected Foreign Correspondents during
the year 1895 :—

Dr. K. de Kroustchoff, of St. Petersburg.
Professor Paul Groth, a Munich.
Professor A. Penck, Be Vienna.

ew

Vol. 52.] ANNUAL REPORT. XXili

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 them 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 Dr. Henry Woodward,
retiring from the office of President.

That the thanks of the Society be given to W. H. Hudleston, Hsq.,
retiring from the office of Vice-President.

That the thanks of the Society be given to Dr. G. J. Hinde, W. H.
Hudleston, Esq., Prof. J. W. Judd, the Rev. H. H. Winwood, and
H. B. Woodward, Esq., 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 :-—

c2

XXIV PROCEEDINGS OF THE GEOLOGICAL socreTy. [May 1896,

OFFICERS AND COUNCIL.—1896.

PRESIDENT.
Henry Hicks, M.D., F.R.S.

VICE-PRESIDENTS.

Prof. T. G. Bonney, D.Sc., LL.D., F.B.S.
Prof. A. H. Green, M.A., F.R.S.

R. Lydekker, Esq., B.A., F.R.S.
Lieut.-General C. A. M*Mahon.

SECRETARIES.

J. KE. Marr, Esq., M.A., F.R.S.
Joo. H.. Teall, Haq, MA. ERS:

FOREIGN SECRETARY.
Sir John Evans, K.C.B., LL.D., F.R.S., F.L.S.

TREASURER.
W. T. Blanford, LL.D., F.R.S.

COUNCIL.
H. Bauerman, Esq. R. 8. Herries, Esq., M.A.
W. T. Blanford, LL.D., F.R.S. Henry Hicks, M.D., F.R.S.
Prof. T. G. Bonney, D.Se., LL.D., | Rev. E. Hill, M.A.
F.R.S. T. V. Holmes, Esq.
Horace T. Brown, Esq., F.R.S. R. Lydekker, Esq., B.A., F.R.S.

Prof. W. Boyd Dawkins, M.A., F.R.S. | Lieut.-General C. A. M°Mahon.
Sir John Evans, K.C.B., LL.D.,| J. E. Marr, Esq., M.A., F.R.S.

ERS. PLS: Prof. Henry A. Miers, M.A.
Sir Archibald Geikie, D.Sc., LL.D., | KE. T. Newton, Esq., F.R.S.
F.RS. F. Rutley, Esq.
Prof. A. H. Green, M.A., F.R.S. A. Strahan, Esq., M.A.
J. W. Gregory, D.Sc. J.J. H. Teall, Esq., M.A., F.R.S.
F. W. Harmer, Esq. Henry Woodward, LL.D., F.R.S.

ASSISTANT-SECRETARY, CLERK, LIBRARIAN, AND CURATOR.
L. L. Belinfante, B.Sc.

ASSISTANTS IN OFFICE, LIBRARY, AND MUSEUM.

W. Rupert Jones.
Clyde H. Black.

Vol. 52.] ANNUAL REPORT. XXV

LIST OF

THE FOREIGN MEMBERS

OF THE GEOLOGICAL SOCIETY OF LONDON, xy 1895.

Date of
flection.

1848. James Hall, Esq., Albany, State of New York, U.S.A.
1851. Professor James D. Dana, New Haven, Conn., U.S.A. (Deceased.)
1856. Professor Robert Bunsen, For. Mem. R.S., Hezdelberg.
1857. Professor H. B. Geinitz, Dresden.

1867. Professor A. Daubrée, For. Mem. R.S., Paris.

1871. Dr. Franz Ritter von Hauer, Vienna.

1874. Professor Albert Gaudry, Paris.

1875. Professor Fridolin Sandberger, Wiirzburg.

1876. Professor E. Beyrich, Berlin.

1877. Dr. Carl Wilhelm Giimbel, Munich.

1877. Dr. Eduard Suess, Vienna.

1879. M. Jules Marcou, Cambridge, Mass., U.S.A.

1879. Dr. J. J. S. Steenstrup, For. Mem. R.S., Copenhagen.
1880. Professor Gustave Dewalque, Lvége.

1880. Baron Adolf Erik Nordenskiold, Stockholm.

1880. Professor Ferdinand Zirkel, Leipzig.

1882. Professor Sven Lovén, Stockholm. (Deceased.)

1882. Professor Ludwig Riitimeyer, Basel. (Deceased.)
1883. Professor Otto Martin Torell, Stockholm.

1884. Professor G. Capellini, Bologna.

1884, Professor A. L. O. Des Cloizeaux, For. Mem. R.S., Paris.
1885. Professor Jules Gosselet, Lvile.

1886. Professor Gustav Tschermak, Vienna.

1887. Professor J. P. Lesley, Philadelphia, Pa., U.S.A.
1887. Professor J. D. Whitney, Cambridge, Mass., U.S.A.
1888. Professor Eugéne Renevier, Lausanne.

1888. Baron Ferdinand yon Richthofen, Berlin.

1889. Professor Ferdinand Fouqué, Paris.

1889, Marquis Gaston de Saporta, Azax-en-Provence. (Deceased.)
1889. Geheimrath Professor Karl Alfred von Zittel, Munich.
1890. Professor Heinrich Rosenbusch, Herdelberg.

1891. Dr, Charles Barrois, Ziile.

1892. Professor Gustav Lindstrom, Stockholm.

1893. Professor Waldemar Christofer Brogger, Christiania.
1893. M. Auguste Michel-Lévy, Paris.

1893. Dr. Edmund Mojsisovics von Mojsvar, Vienna.

1893. Dr. Alfred Gabriel Nathorst, Stockholm.

1894, Professor George J. Brush, Mew Haven, Conn., U.S.A.
1894. Professor Edward Salisbury Dana, New Haven, Conn., U.S.A.
1894, Professor Alphonse Renard, Ghent.

1895. Professor Wilhelm Dames, Berlin.

1895. Professor Grove K. Gilbert, Washington, U.S.A.
1895. M. Friedrich Schmidt, St. Petersburg.

XXV1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [May 1896,

LIST OF
THE FOREIGN CORRESPONDENTS

OF THE GEOLOGICAL SOCIETY OF LONDON, tn 1895.

Date of
Election.

1866. Professor Victor Raulin, Montfaucon d’ Argonne.
1874, Professor Igino Cocchi, Florence.

1874, Dr. T. C. Winkler, Haarlem.

1879. M. Edouard Dupont, Brussels.

1879. Dr. Emile Sauvage, Boulogne-sur-Mer.

1881. Professor E. D. Cope, Philadelphia, Pa., USA.
1882. Professor Louis Lartet, Toulouse.

1882. Professor Alphonse Milne-Edwards, Paris.

1884. M. Alphonse Briart, Morlanwelz.

1884. Professor Hermann Credner, Lezpzig.

1884. Baron C. von Ettingshausen, Gratz.

1887. Senhor J. F’. N. Delgado, Lisbon.

1887. Professor A. Heim, Ziirich.

1887. Professor A. de Lapparent, Paris,

1888, M. Charles Brongniart, Paris.

1888. Professor Anton Fritsch, Prague.

1888. M. Ernest Van den Broeck, Brussels.

1889. Dr. Hans Reusch, Christiania.

1889. M. R. D. M. Verbeek, Padang, Sumatra.

1890. M. Gustave F. Dollfus, Paris,

1890. Herr Felix Karrer, Vienna.

1890, Professor Adolph von Kénen, Géttingen.

1891, Senor Don Antonio del Castillo, Mexico. (Deceased.}
1891. Professor Emanuel Kayser, Marburg.

1892. Professor Johann Lehmann, Kiel.

1892. Major John W. Powell, Washington, D.C., U.S.A.
1893. Professor Marcel Bertrand, Paris.

1893. Professor Aléxis Pavlow, Moscow.

1895. M. Ed. Rigaux, Boulogne-sur-Mer.

1893. Dr. Sven Leonhard Tornquist, Lund.

1893. Dr. Charles Abiathar White, Washington, D.C., U.S.A
1894, Professor Joseph Paxson Iddings, Chicago, Ill., U.S.A.
1894, M. Perceval de Loriol-Lefort, Campagne Frontenex.
1894. Dr. Francisco P. Moreno, La Plata.

1894. Dr. A. Rothpletz, Munich.

1894. Professor J. H. L. Vogt, Christiania.

1895. Professor Paul Groth, Munich.

1895. Dr. K. de Kroustchoff, St. Petersburg.

1895. Professor Albrecht Penck, Vienna.

ol, 52.) ANNUAL REPORT, XXV1i

AWARDS OF THE WOLLASTON MEDAL

UNDER THE CONDITIONS OF THE ‘DONATION FUND’
ESTABLISHED BY
WILLIAM HYDE WOLLASTON, M.D., E.RB.S., F.GS., ere.

‘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.

Mr. William Smith.
Dr. G. A. Mantell.
M. Louis Agassiz.
ee T. P. Cautley.
Dr. H. Falconer.
Sir Richard Owen.

1865,
1866.
1867.
1868.
1869.
1870.

Dr. Thomas Davidson.

Sir Charles Lyell.

Mr. G. Poulett Scrope.
Professor Carl F. Naumann.
Dr. H. C. Sorby.

Professor G. P. Deshayes.

1839. Professor C. G. Ehrenberg. | 1871. Sir A. C. Ramsay.
1840. Professor A. H. Dumont. 1872. Professor J. D. Dana.
1841. M. Adolphe T. Brongniart. | 1873. Sir P. de M. Grey Egerton.

1842.
1845.

1844.
1845.
1846.
1847.
1848.
1849.

Baron L. von Buch.
M. Elie de Beaumont.
M. P. A. Dufrénoy.
Rey. W. D. Conybeare.
Professor John Phillips.
Mr. William Lonsdale.
Dr. Ami Boué.
Rey. Dr. W. Buckland.
Professor Joseph Prestwich.

1874,
1875.
1876.
1877.
1878.
1879.
1880.
1881.
1882.

Professor Oswald Heer.
Professor L. G. de Koninck.
Professor T. H. Huxley.
Mr. Robert Mallet.

Dr. Thomas Wright.
Professor Bernhard Studer.
Professor Auguste Daubrée.
Professor P. Martin Duncan.
Dr. Franz Ritter von Hauer.

1850. Mr. William Hopkins. 1883. Dr. W. T. Blanford.
1851. Rev. Prof. A. Sedgwick. 1884. Professor Albert Gaudry.
1852. Dr. W. H. Fitton. 1885. Mr. George Busk.

1853.

1854,
1855.
1856.

M. le Vicomte A. d’Archiac.

M. E. de Verneuil.
Sir Richard Griffith.
Sir H. T. De la Beche.
Sir W. E. Logan.

1886.

1887.
1888.
1889.

Professor A. L. O. Des
Cloizeaux.

Mr. J. Whitaker Hulke.

Mr. H. B. Medlicott.

Professor T. G. Bonney.

1857. M. Joachim Barrande. 1890. Professor W. C. Williamson.
1858 Herr Hermann von Meyer. | 1891. Professor J. W. Judd.

* | Mr. James Hall. 1892. Baron Ferdinand von
1859. Mr. Charles Darwin. Richthofen.
1860. Mr. Searles V. Wood. 1893, Professor N. 8. Maskelyne.
1861. Professor Dr. H. G. Bronn. 1894. Geheimrath Professor Karl

1862.
1863.
1864.

Mr. R. A. C. Godwin-Austen.

Professor Gustav Bischof,
Sir R. I. Murchison.

1895.
1896.

Alfred von Zittel.
Sir Archibald Geikie.
Dr. Eduard Suess.

XXVili

AWARDS

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

OF THE

[May 1896,

BALANCE OF THE PROCEEDS OF THE WOLLASTON

1831.
1833.
1834,
1835.
1836.
1838.
1839.
1840,
1841.
1842.
1843.
1844,
1845.
1846.
1847.

1848.

1849.
1850.
1851.
1852.
1858.
1854.
1855.
1856.
1857.
1858.
1859,

1860.

1861.
1862.
1863.
1864.

‘DONATION FUND.’
Mr. William Smith. 1865. Mr. J. W. Salter.
Mr. William Lonsdale. 1866. Dr. Henry Woodward.
M. Louis Agassiz. 1867. Mr. W. H. Baily.
Dr. G. A. Mantell. 1868. M. J. Bosquet.
Professor G. P. Deshayes. 1869. Mr. W. Carruthers,
Sir Richard Owen. 1870. M. Marie Rouault.
Professor C. G. Ehrenberg. | 1971, My. R. Etheridge.

Mr. J. De Carle Sowerby.
Professor Edward Forbes.
Professor John Morris.
Professor John Morris.
Mr. William Lonsdale.
Mr. Geddes Bain.

Mr. William Lonsdale.
M. Alcide d’Orbigny.

Cape-of-Good-Hope Fossils.

M. Alcide d’Orbigny.
Mr. William Lonsdale.
Professor John Morris.
M. Joachim Barrande.
Professor John Morris.

Professor L. G. de Koninek.

Dr. 8. P. Woodward.

Drs. G. and F. Sandberger.
Professor G. P. Deshayes.
Dr. S. P. Woodward.

Mr. James Hall.

Mr. Charles Peach.

ae T. Rupert Jones.

Mr. W. K. Parker.
Professor A. Daubrée.
Professor Oswald Heer,
Professor Ferdinand Senft.
Professor G. P. Deshayes.

1872.
1873.
1874.
1875.
1876.
1377.
1878.
1879.
1880.
1881.
1882.
1883.
1884.
1885,
1886.
1887.
1888.
1889.
1890.
1891.
1892.
1893.
1894.
1895.
1896.

Dr. James Croll.
Professor J. W. Judd.
Dr. Henri Nyst.

Mr. L. C. Miall.
Professor Giuseppe Seguenza,
Mr. R. Etheridge, Jun.
Professor W. J. Sollas.
Mr. Samuel Allport.

Mr. Thomas Davies.

Dr. R. H. Traquair.

Dr. G. J. Hinde.
Professor John Milne.
Mr. E. Tulley Newton.
Dr. Charles Callaway.
Mr. J. S. Gardner.

Mr. B. N. Peach.

Mr. J. Horne.

Mr. A. Smith Woodward.
Mr, W. A. E. Ussher. *s
Mr. R. Lydekker.

Mr. O. A. Derby.

Mr. J. G. Goodchild.

Mr. Aubrey Strahan.

Mr. W. W. Watts.

Mr. Alfred Harker.

Wel. 52.|

ANNUAL REPORT.

XXxix

AWARDS OF THE MURCHISON MEDAL

AND OF THE

PROCEEDS OF THE ‘MURCHISON GEOLOGICAL FUND,’

ESTABLISHED UNDER THE WILL OF THE LATE

STR RODERICK IMPEY MURCHISON, Barr., E.R.S., F.G.S.

‘To be applied in every consecutive year in such manner as the Council
of the Society may deem most 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
enquiries 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.
1873.
1874.
1874.
1874,
1875.
1875.
1876.

1876.
1877.
1877.
1878.
1878.
1879.
1879.
1880.
1881.
1881.
1882.
1882.
1883.

1883.
1884,
1884.
1885.

1885.

My. William Davies. Medal.

Professor Oswald Heer.

Dr. J. J. Bigsby. Medal.

Mr. Alfred Bell.

Professor Ralph Tate.

Mr. W. J. Henwood. Medal.

Professor H. G. Seeley.

Mr. A. R. C. Selwyn.
Medal,

Dr. James Croll.

Rev. W. B. Clarke. Medal.
Rev. J. F. Blake.

Dr. H. B. Geinitz. Medal.

Professor Charles Lapworth.

Professor F, M‘Coy. Medal.

Mr. J. W. Kirkby.

Mr. R. Etheridge. Medal.

Sir Archibald Geikie. Medal.

Mr. F. Rutley.

Professor J.Gosselet. Medal.

Professor T. Rupert Jones.

Professor H. R. Gdoppert.
Medal,

Mr. John Young.

Dr. H. Woodward. Medal.

Mr. Martin Simpson.

Dr. Ferdinand von Roémer
Medal.

Mr. Horace B. Woodward.

1886.
1886.
1887.
1887.
1888.

1888.
1889.

1889,
1890.

1890.
1891.

1891.
1892.

1892.
1893.
1893.
1894,
1894,
1895.

1895.
1896.

1896.

Mr. W. Whitaker. Medal.
Mr. Clement Reid.
Rey. P. B. Brodie. Medal.

Mr. Robert Kidston.

Professor J. 8. Newberry.
Medal.

Mr. Edward Wilson.

Professor James Geikie.
Medal.

Professor G. A. J. Cole.

Professor Edward Hull.
Medal.

Mr. E. Wethered.

Professor W. C. Brégger.
Medal.

Rev. R. Baron.

Professor A. H. Green.
Medal,

Mr. Beeby Thompson.

Rey. O. Fisher. Medal.

Mr. G. J. Williams.

Mr. W.T. Aveline. Medal.

Mr. George Barrow.

Professor Gustav Lind-
strom. Medal.

Mr. A. C. Seward.

Mr. T. Mellard Reade,
Medal.

Mr. Philip Lake.

XXX PROCEEDINGS OF THE GEOLOGICAL socrery. [May 1896,

AWARDS OF THE LYELL MEDAL

AND OF THE
PROCEEDS OF THE ‘LYELL GEOLOGICAL FUND,’

ESTABLISHED UNDER THE WILL AND CODICIL OF THE LATE
SIR CHARLES LYELL, Barr., F.R.S., F.G.S.

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 he 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. ; 1888. Professor H. A. Nicholson,

=<
~

Medal. Medal.
1877. Dr. James Hector. Medal. | 1888. Mr. A. H. Foord.
1877. Mr. W. Pengelly. 1888. Mr. Thomas Roberts.
1878. Mr. G. Busk. Medal. 1889. Professor W. Boyd Dawkins.
1878. Professor W. Waagen. Medal. |
1879. Professor Edmond Hébert. | 1889. M. Louis Dollo. :
Medal. 1890. Professor T. Rupert Jones.
1879. Professor H. A. Nicholson. Medal. :
1879. Dr. Henry Woodward. 1890. Mr. C. Davies Sherborn.
1880. Sir John Evans. Medal. , 1891. Professor T. M*Kenny
1880. Professor F. A. von Quen- Hughes. Medal.
stedt. 1891. Dr. C. J. Forsyth-Major.
1881. Sir J. W. Dawson. Medal. | 1891. Mr. G. W. Lamplugh.
1881. Dr. Anton Fritsch. 1892. Mr. G. H. Morton. Medal. |
1881. Mr. G. R. Vine. 1892. Dr. J. W. Gregory.
1882. Dr. J. Lycett. Medal. 1892, Mr, E. A. Walford.

1882. Rev. Norman Glass. 1893. Mr. E. T. Newton. Medal. |
1882. Professor Charles Lapworth. | 1893. Miss C. A. Raisin. Y
1883. Dr. W. B. Carpenter. Medal. | 1893. Mr. A. N. Leeds.

1883. Mr. P. H. Carpenter. 1894. Professor John Milne.
1883. M. E. Rigaux. Medal.
1884, Dr. Joseph Leidy. Medal. | 1894. Mr. William Hill. |
1884, Professor Charles Lapworth. | 1895. Rev. J. F. Blake. Medal.
1885. Professor H. G. Seeley. | 1895. Mr. Percy F. Kendall.

Medal. 1895. Mr. Benjamin Harrison. |
1885. Mr. A. J. Jukes-Browne. 1896. Mr. A. Smith Woodward.
1886. Mr. W. Pengelly. Medal. Medal.
1886. Mr. D. Mackintosh. 1896. Dr. W. F. Hume. J

1887. Mr. Samuel Allport. Meda/. | 1896. Mr. C. W. Andrews.
1887. Rev. Osmond Fisher.

Wal. 52. | ANNUAL REPORT. XXXI

AWARDS OF THE BIGSBY MEDAL,
FOUNDED BY THE LATE

Dr. J. J. BIGSBY, FRS., F.GS.

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. 1887. Professor Charles Lapworth.
1879. Professor E. D. Cope. 1889. Mr. J. J. Harris Teall.
1881. Dr. Charles Barrois. 1891. Dr. George M. Dawson.
1883. Dr. Henry Hicks. 1893. Professor W. J. Sollas.

1885. Professor Alphonse Renard. | 1895. Mr. Charles D. Walcott.

AWARDS OF THE PROCEEDS OF THE BARLOW-
JAMESON FUND,

ESTABLISHED UNDER THE WILL OF THE LATE
Dr. H. C. BARLOW, F.G.8.

‘The perpetual interest to be applied every two or three years, as may
be approved by the Council, to or for the advancement of Geological
Science.’

1880. Purchase of microscope. 1892. Professor Charles Mayer-
1881. Purchase of microscope-lamps. _ Eymar.

1882. Baron C. von Ettingshausen. | 1893. Purchase of Scientific In-
1884. Dr. James Croll. struments for Capt. F. E.
1884, Professor Leo Lesquereux. Younghusband.

1886. Dr. H. J. Johnston-Layis, 1894, Mr. Charles Davison.

1888. Museum. 1896. Mr. J. Wright.

1890. Mr. W. Jerome Harrison. 1896, Mr. J. Storrie.

XXxil PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1896,

Estimates for

INCOME EXPECTED.
£ 8. -d. “So3sme

Compositions, 0c. Me ageless «6 )omlle a cele Ne oe eee 136 0 0
Due for Arrears of Admission Fees .......... 69 6 0
Admission Wees, GGG sn% ec. eke siete eee 180 0
———— 249 6 0
Arrears of Annual Contributions ............ 110 “O. 7%
Annual Contributions, 1896, from Resident Fel-
lows, and Non-Residents, 1859 to 1861 ....1630
Annual Contributions in advance ............ 35
— 1775 0 0
Dividends on £2000 India 3 per cents. ........ 60 0 0
Dividends on £2250 London and North- Western
Railway 4 per cent. Preference Stock ...... 90° Oras
Dividends on £2800 London and South-Western
Railway 4 per cent. Preference Stock ...... 2 OG

Dividends on £300 London, Brighton, and South ,
Coast Railway 5 per cent. Preference Stock.. 15 0 0

Dividends on £1295 Midland Railway 4 per cent.

BEEBE TGE SLOG oe aos « wie cro GERMS iaie ep = shel 5116 0
-— 328 16 0
Sale of Quarterly Journal, including Longman’s
PMECOUM Ec are's ovelern 4 syeis(a «iors = Veena ce sip 8 ie 150 0 0
Sale of Geological Map, including Stanford’s
ENCCOUTL: oor dic cleehe 6 lo's SERA << BAe A. 10. 0 40
Sale of Transactions, Library Catalogue, Orme-
rod’s Index, Hochstetter’s ‘ New Zealand,’ and
PstOL AVAGO YS) ccc cic. s+ 5. PEEL stolen =o sane 5 0 0
— 165 0 0
Balance against Society ............5« 608 6 0
£3262 8 0

Note.—The following Funds are available for Extraordinary Expenditure.

£ se
Balance at the Bankers’, Dec. 31st, 1895 .........0c0ccesccvcocascswccens 8385 5 10
Balance in the Clerk’s hands, Dec. 31st, 1895 ...........cceseeseecees 16 9%

£851 15 5

Vol. 52.] FINANCIAL REPORT.

the Year 1896.

EXPENDITURE ESTIMATED.

Gist ad
House Expenditure :
PR AROR 5 oi5ascrinan sasiamcieee decidsevadnenereneonceene nas 015 0
Reston MSM ANCE Gece nec sssccanecdwateeentmeresecanss toy Or-0
eS es sneer arene cenion oer asses cesar een enc sence see 25.00
BE cia sauce cisdery sjuc snidie desiva s scstatmeneeaatarasnt 30 0 O
urnifure and Kepairs...... 0. </-lasessenveedserss 35 0 0
House-repairs and Maintenance.................. 30 0 0
panirnere|| Clean 3. connparaccesslsceaqtwnsinese see sas LE Oy "0
Mashing and Sundeies.c..2.100-.sssecpecseressss: 25 0 O
per ab) MCCS) «ic ccoscunawcmepencaadaeeemuabsir os 15 0 0
Salaries and Wages, etc.:
IAS SISb AIM SCCRCLAPY! fo acumideeecinn ot snieneesatcsbet ate 300 0 O
Pe Half Premium of Life Insurance 1015 O
PNSSIS AUN, MUU QEATUAT igen ccieececccnadssiscesdenceisceclas 150 0 O
J BETS ENT ul Oh Gye es AS ea eee ae 80 0 0
House Porter and Upper-Housemaid ......... 91 12 O
incdler-FOUSeMaANG) <2.) 02.08: one eeaeaoeuibeds vein’ 42 12 0
PETE ENA OW Ey seme <a ae «scald ome oaiciewesienas 31 4 0
Charwoman and Occasional Assistance......... 1070770
ACH OUMLATEG SUM CO) ea. so csaiewssuesesesienceise seheidentie 10.1050
Prerary, (books and Binding). 4... 6. se deieerde ks ae cle ane
ERs MCE FL oie a eiet acide « « » © weno treene hijo :
Office Expenditure :
READLOMGIY? ceaseless ceetneeSex ens vise veo spaces Ui 255 (OF 8
Miscolancoussbrimting <............seccceseceasss 30 0 0
Postages and other Expenses ............ ...s0.+ 80 0 0
Publications:
colo ical NG Bear ic thins casein ect beres ache 10 0 0
Qimarter ly MOUnia eee access veces +242 -ustenwcies 850 0 O
35 i Commission, Postage,
ANIC NAGLE CRAIN, Mere act iin ndinin os sme eemaeess 100 0 O
Record of Geological Literature ............... TO 100-0
Wists OF OW Oty eee asccc cnn iece cen. oie eee 35 0 0
Abstracts, including Postage ...............00. 110 0 O
Index to Quarterly Journal, vols. 1-50 (sanctioned by Special
General Meeting, Jume 21st, 1893) ....0.0...0.00000
Electric Lighting of Society’s Apartments ..............
Partial Redecoration of Society’s Apartments ..........

xXx eeo

Lacs ad
190 15 0
726 13 0
250 0 0

5 Ono
135 0 0
1180 0 0
375 0 0
300 0 0
100 0 0
£3962 8 0

Se

XXXIV PROCEEDINGS OF THE GEOLOGICAL socreTY. [May 1896,

Income and Expenditure during the

RECEIPTS.
£8. od. Vato
Balance in Bankers’ hands, 1 January,1895. 345 1 8
Balance in Clerk’s hands, 1 January,1895. 13 7 5
a 300849 ¢ al
Compositions oe Merci ae a ve 6) -nlagare os ie ereere eee 305 18 0
Arrears of Admission-fees.............. 13 120)
AGIMISGION-TECSiae oe Mee kiss Co eee 182 14 0
——— 2586. 10
Arrears of Annual Contributions: cc). -0.5 « oe Se L572
Annual Contributions of 1895:
Resident Fellows ......... 1624 17 6
Non-Resident Fellows... lik 30 16
— 1635 18 0
Annual Contributions advance. <6... % «seca io Mekey all)
Taylor & Francis: Advertisements in Journal, Vol. 50.. 15 0
Publications :
Sale of Journal, Vols. 1=50' Jai. e ess So" 0s
2 Volbih® gee ee 7212 8
Sale of. Library Catalogue .............--.--+«- 5 0
Sale of Geological’ Map .....csnteec-e-.n-s<s00e 9 oe
Sale of Ormerod’s: Index... sateeeete wise econ 14 2
Sale of Hochstetter’s ‘New Zealand’ ...... 6 0
Sale of List OnellOws. ....ceeemeet Gescieemcens oc 8 38
-——— 168 9 4
Dividends on L. & N. W. Railway Stock .. 87 0 0
ua L. & 8. W. Railway Stock .. 108 5 4
A L. B. &8.C. Railway Stock.. 1410 0
ms Midland Railway Stock .... 25 0 9
sf 23 p.c. Consolidated Stock.. 50 2 O
a India 3 p: c. Stock... . 29. *O0n0
— 3138 18 1

Sale of £3769 2s. 6d. 22 p.c. Consolidated Stock at
1 ss) a ARRAS hth 3934 0 6

Income Tax:

Repayment of Tax under Schedule C for the year
OAS ODS Gries ss. ERMEIERS spn 8 See ene ae eee 10* 9°
*Due from Messrs. Longmans, in addition to the
above, on Journal, Vol. 51, £62 8s. 1d.

We have compared this Statement
with the Books and Accounts presented
to us, and find them to agree.

(Signed) 3B. H. BROUGH,

R. 8. HERRIES, } Auditors.

January 27th, 1896.
£7183 13 10

Vol. 52.] i FINANCIAL REPORT.

Year ended December 31st, 1895.

PAYMENTS.
House Expenditure: Sens, “a,
EM dela cd aiac's acs. ca on eenannviciachaemmentenaaceb ae 315 0
Rites PSEA NCE! 5.2. cocuerben fe danaatasdies sn aoe 15 0 0
ES SRR ee en 20s ONIN eet 28 pre FF ain lata |
i es kode ks sala eR ue vdnia sce meen em eae 26.900
Barnikure and Hepawwes . 222.2. ...2cenecdoeenne~es 55 4 11
RefonsG: Hepalisy 525.0) Yen shasta ss -aeeeeeeessep = ade aoe
prannal Oleatin gs... 25c cigs. -evs ace eee seal 10:15 0
Passing and Sundries .-:.......sceeccesn0se-- 22 13 2
Plesivdih MCCHINES 1. verona aac osha narnaceeunerssn 13°12) 1
Salaries and Wages:
FESR IS FAG) NECLELAEY re agcsce we nca: ee gaaasnodawes 250 0 O
= Half Life Insurance premium 1015 O
Assistants in Library, Office, and Museum... 251 5 6
House Porter and Upper-Housemaid (inelud- tor 13 3
ing Uniform and Allowance for Washing)
Housemaid (including Allowance for Wash-\ 45 43 3
BE ec te faa rise a) = alle Stine wsiniadnsicnierve.n wa 2
LSC AS A 2D 3, 0
Charwoman and Occasional Assistance ...... 419 0
PMP CORAIAGATED OM CE oc vn cia se cnn wn va gens tence me 10 10 O
‘Office Expenditure:
PR PIMUORREN orale oioens eens aakwivig s« «oe oeeeneowas ao 4 2
MisecllancousErimting J..2.........0sesssseces 45 1 1
Postages and Sundry Expenses ............... 89 5 10
Gratuities to Assistant-Secretary and Assist-
ete EAN a Ee alaoa.. wc us ammannen es 40 0 0
TDL od iy se Be 20 >. ome ee mee
een erat te eee ee Pe. eM le te be gs
Publications :
(Sen a0) Ben 2 ee ence cee ee eee ee 415 7
Afaterarc§ Dekel SS | ee ee Ten Fie Gs ee.
Ses). WOME aI eee... 738 14 1
Commission,
“Postage, ‘and Addressing. 85 9 O
mt
Bape ol Hollen te een Geo. oc... 555 sce 8518 4
Abstracts, including Postage .................. 107 4 5
Geological Viterature ... 2. ..............-c0tes 32 0 9
Index to Quarterly Journal .................. i OO
Investment in £2000 India 3 p. c. Stock
bE OP eee ee EE Se. 8 wl 2082 13 0
Ditto in £1295 Midland Railway 4 p. ec.
Perp. Pref. Stock As eae 1850 19 6

Balance in Bankers’ hands, 31 Dec.1895.. 835 5 10

Balance in Clerk’s hands, 31 Dec.1895.. 16 9 7

W. T. BLANFORD, Treasurer.

MOCK

coy WSs,
Sve 7 70
GOL «42 £0
LOS i ok
Veh OSS
SOS
1086 13 4
3930 12 6
S51 15: 25

£7183 13 10

[May 1896,

XXxXV1

PROCEEDINGS OF THE GEOLOGICAL SOCIETY.

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Vol. 52.] | ANNIVERSARY MEETING—WOLLASTON MEDAL. XXX1X

AWARD OF THE Wo.LtAston MeEpat.

In handing the Wollaston Medal to Sir Joun Evans, K.C.B.,
D.C.L., F.RS., F.LS., Foreign Secretary (for transmission to
Epvarp Svzss, Ph.D., For.Memb.R.S., For.Memb.G.S., Professor
of Geology in the University of Vienna), the Presipent addressed
him as follows :—

Sir Jonw Evans,—

May I request you in your official capacity, as Foreign Secretary,
to receive and transmit to our esteemed Foreign Member, Prof.
Eduard Suess, of the University of Vienna, this Medal, founded by
that eminent man, Dr. Wollaston, in 1828, ‘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.’ Of the
27 occasions on which this Medal has been transmitted to foreigners
it has twice before been awarded to Austrian Geologists, namely,
in 1857, to the illustrious Barrande, and in 1882, to Franz Ritter
von Hauer, Intendant of the Imperial Museum of Natural History
in Vienna and Director of the Geological Survey of Austria.

In speaking of a man so well known as Prof. Suess, words of
commendation on my part are hardly needful. For 39 years
he has occupied the Chair of Geology in the University of Vienna,
and has exercised an influence on the work of the distinguished
school of geologists in that city—including such men as Neumayr,
Mojsisovics, Fuchs, Waagen, Penck, and many others—which proves
him to be a great master of our science. Since 1851 a steady
stream of Memoirs, issued by him, has proved him to be a great
worker in Geology ; while the intellectual stimulus of his writings
on foreign geologists shows him to be a great thinker. He is
worthy of this Award, therefore, not only for the work which he has
accomplished himself, but by what he has roused others to do, not
only by the originality of his own thought, but by the extent to
which he has influenced the minds of others.

Suess is not a specialist. He began work on Graptolites ; he
next laid the foundations of the modern classification of the
Brachiopoda and Ammonites. Alpine problems roused his interest
in Dynamical and Structural Geology, and led to studies of the
Austrian and Italian earthquakes, and to his suggestions of the
onnexion between these and the great circle of European Tertiary

a2

xl PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896,

Volcanoes and the elevation of the Alps. Work on the complex.

Tertiaries of the Vienna Basin and a study of the Mediterranean
littoral geology led to his researches in Faunistic Paleontology, and
so prepared the way for his pupil Neumayr.

Suess’s varied knowledge, penetrative insight, and suggestive
originality are perhaps best exhibited in his ‘ Antlitz der Erde,’
wherein he tried to show the main factors and methods that have
ruled in geographical evolution.

The intimate union thus established pebyese the problems of
Geology and Geography cannot but be regarded as of the highest
importance to the advancement of both sciences, and the world
has been made wiser by the rich stores of knowledge which
Prof. Suess has garnered for geologists and geographers in all
countries.

Prof. Suess has been connected with this Society since 1863, in
which year I made his personal acquaintance when he visited
London. He has now been a Foreign Member since 1876, and is
one of the three oldest foreign geologists on the Society’s List.
His attachment to this country will be better understood when
it is known that Prof. Suess was born in London on the 20th
of August, 1831, his father being at that time a merchant in the
City.

I am sure it will add to Prof. Suess’s pleasure to be told that this
Medal was awarded him by the unanimous vote of the Council, and
that we send, with it, our warmest remembrances and good wishes
for his continued health and prosperity.

Sir Jouw Evans, in reply, said :—
Mr. Presipent,—

The recipient of this Award, whose professorial duties as well
as his advancing age prevent him from attending this Meeting,
has requested me to read the following communication from
him :—

‘By adding my name to the list of those Masters of Geological
Science who have been honoured before me by the award of the
Wollaston Medal, your illustrious Society renders me truly proud,
and I can hardly find words adequate to express my feelings of
gratitude.

‘In addition to field-work, I have for many years laboured to obtain

some approximately comprehensive view of the surface-structure

d
f
‘

:
r
.
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:

Vol. 52.] ANNIVERSARY MEETING—-WOLLASTON DONATION FUND. Xli

of the whole of our planet, and during this endeavour not a day
has passed without bringing again and again before my eyes the
vastness of the British Empire, the world-wide activity of British
geologists and travellers, and the enormous amount of geological
work and learning recorded in the English language.

‘I often and gladly remember the kindness and the instruction
which during the course of my life I have received from my English
masters, and above all from my repeated intercourse with Sir
Charles Lyell, but I dared not think that my own modest essays
would ever be deemed worthy of this distinction—the highest that
English geologists can bestow.

‘This, however, now comes to me at an age when the natural
diminution of physical strength confines me to valley and home;
hammer and belt rest on their peg, and dreams and remembrances
alone still carry me along those Alpine wanderings which form the
highest charm of our incomparable science, and in the lonely
grandeur of which Man feels himself more than ever a child of
surrounding Nature.

‘ In these hours of enforced inactivity, the Award of your Society
leads me to hope that my past exertions have not been quite in
vain; and with deepest thanks I receive this Medal as a token of
indulgence, of encouragement, and also of consolation.’

AWARD OF THE WoLtAston Donation Funp.

The Presrpent then presented to ALFrrep Harker, Esq., M.A.,
F.G.8., of the Geological Survey of Scotland, and of St. John’s
College, Cambridge, the Balance of the Proceeds of the Wollaston
Donation Fund, addressing him as follows :—

Mr. Harxer,—

The Council request your acceptance of the Wollaston Fund in |
recognition of your admirable work in Petrology and your studies in
the Metamorphic and Igneous Rocks and in Dynamometamorphism,
to which you have given such careful attention since you joined our
ranks as a Fellow in 1884.

I have only to allude to your papers%before this Society on the
Gabbro of Carrock Fell and its Granophyres; your petrological
notes on rocks from the Cross-Fell Inlier; your paper on the

xiii PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

eruptive rocks of Sarn, Caernarvonshire ; your joint papers with
Mr. Marr on the Shap Granite and the associated Metamorphic
Rocks,—to show the nature of the work in which you have been

engaged.

Your Sedgwick Essay, on the Volcanic Rocks of Coenen

is a model of what such work should be. It has already received
a well-merited encomium from your present chief, the Director-
General of the Geological Survey.

In the past twelve years you have also been a frequent con-
tributor to the pages of the ‘ Geological Magazine,’ in which some
twenty articles of yours are to be found.

Lastly, your excellent ‘ Petrology for Students,’ issued from the

Cambridge University Press last year, greatly adds to your credit
in this field of research.

This slight recognition from the Council may serve to assure you
how highly your past work has been appreciated, and how much
more good work we trust that you will live to achieve.

Mr. Harker, in reply, said :—
Mr. PresipEnt,—

I heartily thank the Council for the honour which they have
conferred upon me, and yourself for the graceful words with which
you have accompanied this Award.

In the work to which you have made kind reference, I have
confined myself to only one among the several lines of research
recognized by this Society. I have, however, always regarded
Petrology, not as a study apart, but as a branch of Geological
Science ; and whatever value may belong to my results, I owe
in large measure to the fortunate circumstances which have enabled
me constantly to combine work in the field with work in the
laboratory.

Generous appreciation at the hands of those best qualified to
judge is an incentive second only to the pleasure of the work itself.
To the encouragement which I have at all times derived from the
_ comradeship of fellow-workers, both at Cambridge and elsewhere, is
now added that which must always attach to such an honour
as the present one; and for the encouragement, no less than for the
recognition, I tender my best thanks.

Vol. 52. | ANNIVERSARY MEETING—MURCHISON MEDAL. xiii

AWARD oF THE Murcuison MEDAL.

In presenting the Murchison Medal to T. Mettarp Ruanz, Esq.,
C.E., F.G.S., the PRresipENT said :—

Mr. Metiarp Reapz,—

The Council of the Geological Society have awarded to you the
Murchison Medal, in recognition of your work on ‘The Origin
of Mountain Ranges,’ containing the records of much original and
experimental research. Since you joined this Society in 1872 you
have contributed to the various scientific Journals, and to this and
other kindred institutions, more than a hundred papers on geological
subjects, treating of ‘the Geology and Physics of the post-Glacial
Period in Lancashire and Cheshire,’ ‘the Buried Valley of the
Mersey,’ ‘the Drift-beds of the North-West of England,’ ‘the
Chalk-masses in the Contorted Drift of Cromer,’ ‘ Tidal Action as a
Geological Cause,’ ‘the Moon and the Harth, and many other-
kindred subjects bearing upon Dynamical Geology, to which you
have devoted much careful thought and originality of observation
extending over more than a quarter of a century, and have never
permitted an opportunity to slip of adding to our store of geological
knowledge.

This Medal will serve to assure you that, although not often
present at our Meetings, and living at a distance from town, you
are neither overlooked nor forgotten by your fellow-geologists here,
nor have your labours been unappreciated.

Mr. Metrarp Reape replied as follows :—
Mr. PresipEnt,—

It is with mingled feelings difficult, nay impossible, to express -
here, that I receive the Medal founded by the illustrious author of
‘Siluria,’ which the Council of this Society, in the exercise of their
functions, have thought fit to award to me. If one circumstance
more than another could add to the pleasure which the Award affords
me, it is, Dr. Woodward, that I receive it through you as President of
this Society. I cannot forget that my first little geological venture
was launched in the columns of the ‘ Geological Magazine,’ and that
ever since you have proved to be a true and consistent friend.

As regards the work and researches of which you have so favour-
ably spoken, it is for others to assess their value, and for me to

xliv PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

rejoice that they have been considered worthy of so handsome a
recognition. Like the founder of this Medal, I began the study of
Geology in middle life, and doubtless the direction and the character
of my researches have been profoundly influenced by previous pro-
fessional training as well as by natural bias. The study of Geology
has been to me a labour of love as well as an interesting and
healthful recreation. It has also been an education. Doubtless
some of the work to which I have directed my attention has been of
an arduous nature; but, as Shakespeare says,
~ «The labour we delight in physics pain.’

It now only remains for me to thank the Council and yourself for
this much appreciated recognition of my small services to Geological
Science, and to assure you that the addition of my name to the dis-
tinguished list of Murchison Medallists is calculated to inspire and
support me in any further work which in God’s providence I may
be permitted to carry out.

AWARD oF THE Murcuison GrotogicaAL Funp.

The Presipent then presented the Balance of the Proceeds of the
Murchison Geological Fund to Puirie Laxs, Esq., M.A., F.GS.,
addressing him in the following words :—

Mr, Laxr,—

The Council of the Geological Society have awarded to you the
Balance of the Proceeds of the Murchison Geological Fund, in
recognition of your work in India, too soon interrupted by ill-
health. Before you left, however, you had made a solid contri-
bution to the history of the origin of the remarkable Laterites
of that region (Mem. Geol. Surv. India, vol. xxiv. Art. 3, 1890),
as well as to some other Indian geological problems. You have
now commenced in Wales: first, in conjunction with Mr. T. T.
Groom, at Corwen (Quart. Journ. Geol. Soc. 1893, vol. xlix. p. 426),
and at a later date alone, near Llangollen (bid. 1895, vol. li. p. 9),.
you have given the Society careful and accurate contributions on
the Geology of these difficult regions.

Nor have you neglected Paleontological studies, as your recent
paper on Acidaspis bears testimony.

It is hoped that this Award may prove not only useful, but that
it may serve as an incentive to continued and important geological
work in the near future.

Wel) '52.| ANNIVERSARY MEETING—LYELL MEDAL, xlv

Mr. Laxs, in reply, said :—
Mr. PResIDENT,—

I am deeply sensible of the honour which the Council have done
me in making this Award ; for to a labourer in the cause of science
there is no truer pleasure than the appreciation of his labours by his
fellow-workers. It is an additional gratification that it should fall
to my lot to receive the Award at your hands, since of late I have
attempted to follow in your footsteps in the field which you have
made so peculiarly your own.

I feel, however, that the Award is a recognition far beyond what
my work has hitherto deserved; and I look upon it rather as an
encouragement to persevere in the researches which I have begun.

AWARD OF THE Lyett MEDAL.

In presenting the Lyell Medal to ArtHur Smira Woopwarp,
Esq., F.L.S., F.G.S., the Presipent said :—

Mr. ArrHur Suita Woopwarp,—

The Council of the Geological Society have awarded you the
Lyell Medal, because it appeared to them that the Palxontological
work to which you have so earnestly devoted your life since you
commenced your career in the British Museum in 1882 would have
met with the cordial approval of the distinguished geologist and
writer who founded this Award.

Trained at the Owens College, Manchester, you had, besides this,
an innate love of scientific work, and only needed the opportunity
to develop into an accomplished palzontologist of the Vertebrata.

In dealing with the whole field of Fossil Vertebrata, you wavered
at first between the varied groups to which your studies invited you;
but, after a few papers on Mammalia and Reptilia, you turned with
a steady resolve to the study of Fossil Fishes, from which you have
scarcely ever departed. More than one hundred papers on Fossil
Fishes, besides a descriptive and illustrated Catalogue of Fossil Fishes
in the British Museum, of which three volumes have already appeared
(1889-95), and two Memoirs on the Fossil Fishes of New South
Wales, attest the settled life-line of research to which you now
stand committed.

xlvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,,.

But we have to thank you also for a joint work with Mr. C.
Davies Sherborn, F.G.S8., of the very greatest usefulness to palzon-
tologists, ‘A Catalogue of British Fossil Vertebrata,’ 1890—a.
most trustworthy and excellent compilation, critically and carefully
prepared.

That in the space of fourteen years you should have accomplished

so much good work, is due to the fact that you have never wavered

from the object which you had set before your mind to accomplish,,.

and even in your numerous journeys in Kurope and to North America
you have ever kept your Ichthyological researches steadily in view.

I trust that this Medal, and the good wishes which accompany it
from your friends here, will encourage you to the completion of your
labours on the Fossil Fishes, and that the remaining group of the
Teleosteans may enjoy the same careful and critical attention and
study at your hands as you have bestowed upon the other and earlier
groups.

Mr. Suira Woopwarp, in reply, said :—
Mr. PResipENT,—

I desire to express my thanks to the Council of the Geological
Society for the great honour that they have done me in making this.
Award, and to yourself, Sir, for the very kind and complimentary
terms in which you have presented the Medal. During the last
thirteen years I have merely tried to make the best use of the
opportunities for research afforded by my official connexion with
the British Museum ; and the gratification experienced in the pur-
suit of duty of this kind is in itself so ample a reward for the labour

involved, that a naturalist thus circumstanced scarcely looks for

anything beyond it. When, however, the honourable marks of
approbation officially bestowed are unexpectedly coupled with so
highly esteemed a distinction as the award of the Lyell Medal by the
Geological Society of London, I feel doubly encouraged to persevere
and endeavour to merit the compliments that have been expressed.

I was first led to take a special interest in extinct Fishes by
attending Dr. Traquair’s course of Swiney Lectures on the subject
in 1888. I was thus enabled to apply to this field of research the
methods that I had previously learned from Prof. Boyd Dawkins
when a student in the Owens College. Since that time the kindly
encouragement of so many friends—yourself and the late Mr. William
Davies among the foremost—has made progress easy ; and the very

Vol. 52.] ANNIVERSARY MEETING—LYELL GEOLOGICAL FUND. xvii

fortunate circumstance that most of the larger private collections of
Fossil Fishes in this country have now been acquired by the British
Museum, has afforded me favourable opportunities for study such as
have never been enjoyed by any one previously. The biological
problems suggested by these fossils seem to me to outweigh in interest
the geological questions connected with them to so great a degree,
that I have rarely been able to look upon them from any but a
morphologist’s point of view ; and all the more on this account do
I appreciate the high honour that is conferred upon me by the
Geological Society to-day.

AWARD OF THE LYELL GEOLOGICAL FuND.

The Presrpent then presented one-half of the Balance of the
Proceeds of the Lyell Geological Fund to Dr. Wittiam Fraser
Hume, Assoc.R.S.M. & R.Coll.Sci., F.G.S., and addressed him as
follows :—

Dr. Hume,—

Although for several years you have been actively engaged as a
Demonstrator in Geology in the Royal College of Science, you have
not allowed any opportunities for doing original work in the field
to escape you; and your essay on the Chemical and Micro-minera-
logical Structure of the several zones of the Upper Cretaceous rocks
of the South of England illustrates admirably how such detailed
work should best be carried out.

Your papers on the ‘ Black-Earth,’ ‘ the Loess,’ and on the Chalk
of Russia, ‘ on the Genesis of the Chalk,’ and on ‘ Oceanic Deposits,’
indicate the bent of your researches towards the microscopic inyves-
tigation of rocks—a line of study which Dr. H. C. Sorby, F.R.S., a
past President of this Society, so profitably engaged in.

The Council hope, by the presentation of this Award, not only to
mark their appreciation of your past researches, but to encourage
you to extend them to other formations with the same useful
results. ,

Dr. Hume replied as follows :—
Mr. Presiprnt,—

At times a feeling of despondency has crossed my mind, when I

xlviil PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1896,

have considered the vastness of our subject, and the smallness of
the contributions which I have endeavoured to add to our know-
ledge of the past; it is therefore a great encouragement to
receive this mark of approval from those whose opinion we most
value and esteem. It would, indeed, have been strange if, with
the resources of the Royal College of Science at my disposal, I
had not availed myself to the utmost of such exceptional oppor-
tunities.

Two facts afford me special gratification on the present occasion :
the first, that this Award should be intimately connected with the
great geologist whose historical and geographical methods I have
been most anxious to follow to the best of my ability ; the second,
to receive it from you, seeing that you were the editor who piloted
with friendly hand my first publication, at a time when it was
especially in your power to damp or re-inspire the ardour of a young
enthusiast. Therefore, to you, Sir, to the Council, and to the kind
friends who have aided me by active counsel or friendly criticism, I
hereby tender my most warm and hearty thanks.

The Prusrpent then handed the other moiety of the Balance
of the Proceeds of the Lyell Geological Fund to CHartzs W.
AnpREws, Esq., B.A., B.Sc., F.G.8., of the British Museum (Natural
History), and addressed him as follows :—

Mr. ANDREWs,—

Although your scientific career has been but a short one, you
have lost no time in engaging in active and earnest studies in the
Comparative Osteology of the Fossil and Living Vertebrata, and
have already done some excellent work on the remains of the extinct
gigantic Birds from Madagascar and from other parts of the world.
Your papers on Keraterpeton from the Coal Measures, and on the
Oxfordian genera of Plesiosauria, prove that you have already
acquired an accurate knowledge of many points of detail in the
structure of these extinct Reptiles which can only be appreciated by
an equally careful study of existing forms. |

In making this Award, the Council desire not only to assist and
encourage you in the work which you have taken in hand with so
much enthusiasm, but they have a confident expectation that you
will ere long contribute papers to their Proceedings, which shall do —
honour to their prescience and bring xvdos to yourself.

Vol. 52.] ANNIVERSARY MEETING—BARLOW-JAMESON FUND. xlix

Mr. AnpRews, in reply, said :—
Mr. PResipENT,—

I wish to express my sincere thanks to the Council for the great
honour that they have done me, and to you, Sir, for the altogether too
kind remarks that youhave made. It was always my earnest desire
to study the structure of animals, but in my wildest dreams I never
hoped to have such opportunities as I now enjoy at the Natural
History Museum, and I feel continually a sense of responsibility
and fear lest I should prove unequal to the task which lies before
me. Having now received this Award, I am still further bound in
honour to do my utmost to justify it, and to fulfil as far as possible
the expectations that you have expressed.

AWARD oF THE BARLOW-JAMESON F'unD.

In handing a moiety of the Barlow-Jameson Fund to Dr. G. J.
Hinpez, F.G.8. (for transmission to JosepH Wricut, Esq., F.G.S., of
Belfast), the President addressed him as follows :—

Dr. HinpE,—

The Council have awarded the sum of Twenty Pounds from the
Barlow-Jameson Fund to Mr. Joseph Wright, in recognition of the
valuable services that he has rendered to the Paleontology, not
only of the Carboniferous rocks in the South, but of the Cretaceous
and Post-Tertiary deposits in the North of Ireland, and the Glacial
deposits there, and in Scotland.

Mr. Wright is the author of numerous papers in the Transactions
of the Belfast Naturalists’ Field-Club, on the Irish Liassic and
Cretaceous Foraminifera and other Microzoa; he has also prepared
and published many lists of Foraminifera from the Scottish and Irish
Boulder-Clay and other post-Tertiary deposits.

He has done much good work, extending over many years, when
resident in the South of Ireland, in connexion with the fossils of
the Carboniferous Limestone, and both as regards these, and the
newer deposits of the North, his specimens have been always
available to any one engaged in writing on the fossils. To
Davidson, Rupert Jones, Holl, Brady, myself, and others Joseph
Wright’s cabinet was ever accessible and his specimens were freely
lent for study.

if PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

I trust that this Award will serve to express to Mr. Wright our
appreciation of his services, and will act as an incentive to him to
continue his useful geological work.

Dr. Hinvz replied as follows :—
Mr. PREstpENT,—

It gives me great satisfaction to receive this Award on behalf of
my friend Mr. Joseph Wright. He is unfortunately unable to be
present, and has sent the following letter for communication to
you :—

‘I desire to express my sincere thanks for the honour conferred
upon me by the Council of our Society in recognition of my past work,
and for their assistance in the further prosecution of my researches.
Working so remote from the headquarters of the Society causes this
Award to be the more appreciated.

‘I regret that I am prevented from being present to receive it
in person, but I hope that the Council will accept this expression
of my feelings regarding their approval of my work in a somewhat
neglected field.

‘For some years past nearly all my spare time has been spent in
microscopically examining the Glacial Clays for Foraminifera. My
anticipation as to the occurrence of these organisms in Clays laid
down under glacial conditions has been fully confirmed both as
regards our local deposits and other British Clays, and I cannot
avoid thinking that this fact must more or less influence our views
as to the origin of these drifts.’

In handing to A. Strawn, Hsq., M.A., F.G.S. (for transmission to
Mr. Joun Srorrtie, of Cardiff), the second moiety of the Award made
from the Barlow-Jameson Fund, the Presmpenr addressed him as
follows :—

Mr. StraHan,—

The Council have accorded to Mr. Storrie the sum of Twenty
Pounds from the Barlow-Jameson Fund, in recognition of his
services for the advancement of Geological Science while in charge
of the Cardiff Museum, and, subsequently, as a volunteer worker on
the Geology of South Wales. Mr. Storrie, I am informed, was the
first to detect and describe an actual exposure of the base of the
Old Red Sandstone near Rumney, and his researches have done

‘Vol. 52.] ANNIVERSARY MEETING—BARLOW-JAMESON FUND. hi

much to elucidate the obscure plant-remains from the Silurian rocks
of that locality.

In the Rhetic and Triassic strata he found and fixed the exact
horizon of certain fossils new to the district, while in the latter he
made an interesting discovery of grains of gold. His intimate and
accurate knowledge of the Cardiff area proved of great service to
Geologists at the time when the British Association held its meeting in
that town. Indeed few Geologists have worked in the neighbourhood
of Cardiff without being indebted to him for assistance.

[have much pleasure in handing you this Award for transmission
to Mr. Storrie.

Mr. Srraway, in reply, said :—
Mr. PrestpEnt,—

It will be a great pleasure to me to forward this Award to
Mr. Storrie. The pages of our Journal testify to the value of the
aid that he has rendered to many Fellows of the Society. I have
myself been indebted to him for most valuable assistance in the
geological mapping of the neighbourhood of Cardiff. Mr. Storrie
writes to me :—

‘I regret that it will not be in my power to attend personally
to thank the President and Council for the great honour that they
have done me.

‘TI am afraid that up to now I have not done enough to warrant
my selection, but if ever I am able in future to do anything in the
way of original work I shall be very anxious to justify this choice
and give my whole mind to the accomplishment of the best work
possible.

‘ You will, I hope, convey in better words than I can the extreme
gratitude which I feel for the Award.’

lii PROCEEDINGS OF THE GEOLOGICAL socieTY. [May 1896,

THE ANNIVERSARY ADDRESS OF THE PRESIDENT,
Henry Woopwarp, LL.D., F.RB.S.

GENTLEMEN,—

The past year has left behind it a long and mournful record in
our ‘Street of Tombs,’ and, as my own allotted time is so brief
to-day, I would suggest that we should each entwine a garland of
laurels and immortelles in memory of those whose names we
honour, and so, hammer in hand, go forward.

Of aged Fellows, one, Robert Fitch, of Norwich, had reached
his 93rd year. He was a contemporary of my father, Samuel
Woodward, the Norfolk geologist, but twelve years his junior. Six
Fellows and two Foreign Members—namely, Prof. C. C. Babington,
the Ven. Archdeacon Browne, Sir E. H. Bunbury, James Carter of
Cambridge, Mr. E. J. Chance, Gen. Copland-Crawford, Prof. J. D.
Dana, and Prof. Sven Lovén—were between 80 and 90 years
of age. Six Fellows and two Foreign Members—the Marquis de
Saporta, Rt. Hon. T. H. Huxley, Prof. L. Ritimeyer, the Hon.
Walter Mantell, Mr. P. H. Lawrence, Mr. E. A. Winsch, the
Rey. E. Duke, and Mr. Richard Carter—were between 70 and 80
years of age. Hight Fellows—namely, Mr. J. W. Hulke, For. Sec.,
Mr. T. J. Slatter, Dr. J. E. Taylor, Mr. Charles Tyler, Rev. Lester
Lester, Mr. J. Walter Tayler, Mr. W.S. Milnes, and Dr. G. W. Cline
—were between 60 and 70. The remaining five were between 35
and 60:—Prof. Valentine Ball, C.B., Mr. J. Mitchell, Mr. G. F.
Hosking, Mr. Hugh Miller, and Mr. J. E. Williams.

We have lost two Past Presidents: the Rt. Hon. T. H. Huxley,
P.C., and Mr. J. W. Hulke, For. Sec.; four Foreign Members :
namely, the Marquis de Saporta (France), Prof. J. D. Dana (United
States of America), Prof. S. Lovén (Sweden), Prof. L. Ritimeyer,
M.D. (Switzerland); and one Foreign Correspondent, Sr. Don
Antonio del Castillo (Mexico).

Three of these were also Wollaston Medallists. Another Wol-
laston Medallist died last year who was not a Fellow of this
Society,—Prof. W. C. Williamson, F.R.S. (@t. 78). Williamson was
distinguished as a paleobotanist, and was for many years Pro-
fessor of Botany in Owens College, Manchester. His collection,
illustrative of the structure of Fossil Plants of the Coal-Measures,
has just been acquired by the Trustees of the British Museum.

Vol. 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. lik

The Marevis of Sarporta, who was a Corresponding Member of
the Institute of France, and a Foreign Member of the Geological
Society of London since 1859, was born at Saint-Zacharie (Var) in
1823. He spent some time in a Jesuit college at Fribourg, and
in 1861, in conjunction with M. Matheron, published his first
paper on a paleobotanical subject, ‘ Examen analytique des Flores
tertiaires de Provence.’ From that date up to the time of his
death, which occurred on January 26th, 1895, Saporta devoted
himself, as a keen student, to the problems of his chosen science.

His earlier works dealt especially with the Tertiary vegetation
of the South-east of France; the floras of Aix, Manosque,
Sézanne, and other localities, have formed the subjects of elaborate
monographs, in which he has not merely recorded lists of fossil
species, but has dealt with the facts from a broad and philosophic
standpoint. Between the years 1872-91 there appeared the
splendid series of volumes on ‘the Jurassic Flora of France’: this
comprehensive work, with its numerous illustrations and exhaustive
text, forms an indispensable handbook to students of Mesozoic
Botany. Saporta’s most recent work, on ‘ Upper Jurassic and
Lower Cretaceous Plants,’ appeared a few months before his death,
‘Flore fossile du Portugal (Direction des Travaux géologiques du
Portugal), 1895.’ It contains a detailed geological and botanical
analysis of an exceedingly interesting flora, and supplies fresh facts
of considerable importance towards a more complete knowledge of
the early history of dicotyledonous plants.

In addition to his numerous papers on paleobotany, Saporta has
left such works as ‘Le Monde des Plantes avant l’Apparition de
?Homme,’ ‘ Origine paléontologique des Arbres cultivés ou utilisés
par Homme,’ and, in collaboration with Prof. Marion, ‘L’Evolution
du Reégne végétal’; these form fitting memorials of his wide
knowledge as a paleobotanist, and of his zealous advocacy of the
importance of fossil forms to the student of plant-evolution. By some
readers Saporta is perhaps best known as the too eager upholder
of the claims of certain structureless casts and impressions to be
included among fossil alge. The valuable contributions to this
subject by Nathorst have clearly shown how little weight must be
attached to any speculations as to the development of plant-life based
on Saporta’s ‘ Algues fossiles’ or his ‘Organismes problématiques
des anciennes Mers.’

As a contributor to Tertiary and Mesozoic botany, Saporta’s name
will always be associated with that of Heer and Ettingshausen ;

VOL, Lil. €

liv PROCEEDINGS OF THE GEOLOGICAL socrery. [May 18096,

and the later generation of workers in this branch of pale-
ontology may well look upon him as a worthy pupil of Adolphe
Brongniart, whose philosophic spirit and scientific handling of facts
are reflected in the writings of his younger countryman. The
writer of a recent obituary notice in a French scientific journal
has thus happily expressed Saporta’s unfailing industry: <A des
travaux considérables succédaient des entreprises plus considérables
encore, et l’on oubliait age en voyant l’ceuvre s'augmenter et les
horizons s’étendre toujours. —{ A.C. 8, ]

JoHN WuitakerR Herre, F.R.S., President of the Royal College
of Surgeons of England; Foreign Secretary of the Geological Society
of London.

Only four days after the Anniversary Meeting last year, in the
plenitude of his honours, and in the faithful discharge of his duties
for the alleviation of suffering humanity, our late Foreign Secretary
gave up his life. As senior surgeon he was summoned to Mid-
dlesex Hospital to perform an operation on February 7th, one of
the most terribly severe nights of that exceptionally trying month ;
he returned home, fatigued and suffering from bronchitis, at
3.30 a.m., but attended and operated at the hospital on the 9th;
visited his patients again on the 10th and 11th, when serious
illness prostrated him, and he succumbed on the 19th February
to pneumonia.

John Whitaker Hulke was born on November 6th, 1830, being
the elder son of a well-known and widely respected general practi-
tioner at Deal. The original family name was Hulcher, his ancestors
being Dutch by origin, who had escaped from Holland during the
Spanish persecutions under Philip II. and Ferdinand, Duke of Alva,
and settled on the Kentish coast. There for some two hundred
years they have followed the vocation of medicine. He was
educated at King’s College School, and at Neuwied, in Germany,
and at the age of nineteen entered the medical school of King’s
College, where he was a dresser to Mr. (afterwards Sir) William
Bowman, and house-surgeon to Sir William Fergusson. It was
while he occupied this position that he attended the Duke of
Wellington in his last illness, his father being the Duke’s regular
medical attendant and obtaining leave to avail himself of his son’s
services as assistant. In 1854, when the Crimean War broke out,
he was early to volunteer, and at the beginning of 1855 was
appointed assistant surgeon to the British Civil Hospital at Smyrna.
Thence he was sent to Sebastopol, and in that awful campaign of

Nol 52] ANNIVERSARY ADDRESS OF THE PRESIDENT. lv

irremediable sickness, gross mismanagement, and gallantry as often
as not ineffective, bore himself, in the opinion of everyone, with
patient courage as a brave soldier.

On his return from the East he became medical tutor of King’s
College Hospital, and, having previously been elected a Fellow of
the Royal College of Surgeons of England, was appointed, in 1858,
assistant surgeon to Moorfields Hospital. He had previously been
elected assistant surgeon to King’s College Hospital, where, haying
duly served his allotted period, he was appointed, together with
Dr. Charles Murchison, a colleague at King’s, to the Middlesex
Hospital, of which institution he was the senior surgeon at the
time of his death.

Mr. Hulke’s earliest mark was made in ophthalmology. He
obtained the Jacksonian Prize of the Royal College of Surgeons
of England for an essay on the Morbid Changes of the Retina;
his treatise on the Use of the Ophthalmoscope (1861) formed an
excellent introduction for most of the profession to the new system
of intraocular examination ; his Arris and Gale Lectures, delivered
before the Royal College of Surgeons, and subsequently published,
dealt with the Minute Anatomy of the Eye.

Mr. Hulke was elected a Fellow of the Royal Society in 1867,
his claim being based exclusively on researches relating to the
anatomy and physiology of the retina in man and the lower animals,
particularly in the reptiles. These were embodied in two papers
in the ‘ Philosophical Transactions’ (‘On the Anatomy of the Fovea
centralis of the Human Retina,’ and ‘On the Chameleon’s Retina’),
and in a paper on the ‘ Retina of Amphibia and Reptiles,’ in the
first volume of the ‘Journal of Anatomy and Physiology.’ These
are characterized by patient and conscientious minuteness in the
working out and description of details, and cautious reserve in
drawing inferences. Probably the most important and permanently
valuable of Mr. Hulke’s researches were those relating to the Retina
of the Chameleon, which the abundant material at his disposal
enabled him to elaborate in a more complete manner than had
‘before been possible.

Mr. Hulke served on the Council of the Royal Society during
1879, 1880, 1888, and 1889; and was also a Member of the
Scientific Relief Committee. His communications to the Trans-
actions of that Society were numerous, and the last of them was
read before it on May 12th, 1892—‘On the Shoulder-girdle in
Ichthyosauria and Sauropterygia.’

Very soon after he became a Fellow of the Royal Society Hulke

e2

lvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

transferred his allegiance to geology, between which and his pro-
fession as a consulting surgeon his energies were thenceforth to be
divided. Had he continued his anatomical studies he would
without doubt have attained to the foremost rank among physio-
logical anatomists.

During the quarter of a century which followed his first con-
tributions to geological science, Mr. Hulke found leisure to apply
himself to research in this field, notwithstanding his constantly
increasing practice. He did so to so good a purpose that he became
a paleontologist of no ordinary merit. His knowledge of compara-
tive anatomy, and especially of osteology, enabled him rapidly to
grasp the meaning of structures presented by the remains of fossil
vertebrates ; and this, combined with a naturally keen perception
and a rigid adherence to facts, soon caused his opinion on paleonto-
logical matters to be sought, and held in the highest estimation.

It was the fossil Reptilia which more especially occupied Hulke’s
attention, and his numerous papers on their osteology are a monu-
ment to his industry. Many of the fossils which he described
were, in part at least, freed from the matrix by his own facile
chisel; and in this mechanical work, as he himself has said, he
often found relaxation when his mind was overwrought by profes-
sional anxieties.

Mr. Hulke’s well-earned vacations were often spent at localities
of geological interest, more especially with a view to working out
the fossils which might be obtained. For this purpose he paid
frequent visits to Brook, in the Isle of Wight, whence have come
many specimens of Wealden Dinosauria; near here also, at Brixton,
was preserved the unique collection of these Wealden reptiles, made
by the Rev. W. Fox. For many years Mr. Hulke was the only
paleontologist who had free access to this collection; and he did
much good work in bringing to light its hidden treasures, which
would otherwise have remained almost unknown until after the
death of the owner, when they were acquired by purchase for the
British Museum.

In the year 1868, Mr. Hulke was elected a Fellow of the Geological
Society of London, and from that time onwards the pages of the
‘Quarterly Journal’ of that Society were frequently enriched by his-
writings. No fewer than six of his papers were published in the
two volumes which followed the year of his election, and these, with
one exception, were descriptions of Saurian remains from the Kim-
meridge Clay of Dorset. Several other papers on reptiles from the

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lvii

same locality appeared in subsequent volumes ; but Mr. Hulke was
more particularly interested in the Dinosauria, and many con-
tributions to the osteology of this interesting group of reptiles have
appeared in the ‘ Quarterly Journal’ of the Geological Society, and
in the ‘ Philosophical Transactions’ of the Royal Society.

Our first knowledge of the cranium of Jguanodon was due to
Mr. Hulke’s work upon a specimen from the Isle of Wight, which
completely revealed the brain-cavity, but, as it did not include the
facial bones, its affinities were by no means easy to determine.

In 1873 and 1874 Mr. Hulke made additions to our knowledge
of the small Wealden Dinosaur, which had been named by Professor
Huxley Hypsilophodon Foxw; and in 1882 a still more important
memoir on the same species was published in the ‘ Philosophical
‘Transactions.’ |

In 1874 and 1876 he showed that a certain bone of Jguanodon,
which had been regarded as a scapula, was really a part of the
pelvis; and, indeed, it proved to be the remarkable pubis of that
reptile, which so nearly resembles that of a bird.

In 1879 the two genera, Poikilopleuron and Megalosaurus, were
proved by him to be one and the same Dinosaurian genus. In the
same year he described the remains of a new Wealden Dinosaur
under the name of Vectisaurus valdensis; and in 1880 he made
known one of the most perfect Iguanodons discovered in this
country, obtained by Prof. (now Sir) Joseph Prestwich, from the
Kimmeridge Clay of Cumnor, which he named Jguanodon Prest-
wichir. .

In the following year there appeared in the ‘ Philosophical
Transactions’ Mr. Hulke’s memoir on Polacanthus Foxti. This
remarkable Dinosaur, the name for which had been suggested by
Sir R. Owen, has a broad dermal shield spread out above the iliac
bones in such a way as to form a kind of carapace over the lumbar
and sacral regions; besides this, large spines and scutes were
attached to other parts of the animal’s body.

Mr. Hulke’s presidential addresses to the Geological Society,
1883-84, formed an important contribution to our knowledge of
reptilian osteology, and especially threw light on the structure of
the shoulder-girdle in Plesiosaurs and their allies.

The Iguanodont-remains found in England have been more or
less fragmentary, and discoveries made by other workers which
might serve to elucidate their structure were always hailed by
Mr. Hulke with extreme satisfaction. No one more heartily

lviil PROCEEDINGS OF THE GEOLOGICAL sociury. [May 1896,.

rejoiced than he did when the geologists of Belgium made known
the discovery of the series of magnificently perfect Jguanodon
skeletons, a facsimile of one of which now adorns the Museum
of Natural History in Cromwell Road.

Mr. Hulke served for many years on the Council of this Society,
and the high esteem in which he was held by the leading geo-
logists of the day, as well as the thorough appreciation of his
paleontological work, found expression by their electing him, in
1882, to fill the Presidential chair of this Society, and, in 1887,
by presenting him with the Wollaston Gold Medal, the greatest
honour that it was in the power of the Council to bestow. In 1891
he was elected Foreign Secretary of the Geological Society, which |
office he still held at the time of his decease.

Mr. Hulke left behind him a large series of most valuable speci-
mens, mostly of Dinosauria, obtained with his own hands from the
Undercliff in the Isle of Wight. This collection has been presented
to the British Museum (Natural History) by Mrs. Hulke,in memory
of her husband.

Lieutenant-General R. F. Coptanp-Crawrorp, R. A., was elected
a Fellow of the Geological Society of London in 1875, and died at.
his residence, Sunbury Lodge, near Wembley, Harrow,on March 5th,
1895, in his 85th year.

He was for many years a constant attendant at the Anniversary
Meetings of the Paleontographical and Geological Societies, and.
his handsome, tall figure, military bearing, and his graceful method.
of proposing resolutions on such occasions will be remembered by
many Fellows. He was not a writer, but a reader of geological
literature.

Sir Epwarp Hersert Bonsury, Bart., was born in 1811, and
educated at Trinity College, Cambridge, where, in 1833, he
graduated B.A. (was senior classic and Chancellor’s Medallist), and
M.A. in 1836. Five years later he was called to the Bar of the
Inner Temple, and was M.P. for Bury St. Edmunds from 1847 to
1852. He was elected a Fellow of the Geological Society in 1837,
but does not appear to have communicated any paper to the
‘Quarterly Journal. Sir Edward Bunbury brought out his
‘History of Ancient Geography ’ in 1879, and was a contributor to
Sir William Smith’s ‘ Dictionaries of Greek and Roman Biography
and Geography,’ especially the latter. He died on March 5th,
1895, in his 84th year.

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lix

Rosert Fire, F.S.A.—Geology, like other branches of Natural
History, bas owed much of its progress to the zeal of collectors.
Of these, one of the most painstaking and successful was the late
Robert Fitch, who, in addition to a most valuable collection of
antiquities, had gathered together a very fine series of fossils from
the Crag and Chalk of Norfolk. He was born at Ipswich, on
October 21st, 1802, educated at the Grammar School, and appren-
ticed to a chemist and druggist in the town. Pursuing this
occupation he settled at Norwich, in 1827, in partnership with
Mr. Sheriff Chambers, and continued until he was over 90 years of
age to take an active interest in business. From an early date
he took great pleasure in fossils, and his specimens were always at
the service of those engaged in paleontological studies.

He seldom wrote on geological subjects, his chief literary con-
tributions being to the ‘ Transactions of the Norfolk Archeological
Society.’ In 1836, however, he communicated to the Geological
Society an account of the discovery of the tooth of a Mastodon in
the Crag at Thorpe, near Norwich; and in 1840 he sent to the
‘Magazine of Natural History’ a ‘Notice of the existence of a
distinct Tube within the hollows of the Paramoudra.’ In later
years he announced before the Norwich Geological Society the
finding of Deer’s antlers in re-deposited Chalk at Hartford Bridges,
near Norwich; and also the discoveries of Flint Implements in the
valley of the Little Ouse.

His fine collection is placed in a special room in the new Museum
buildings at Norwich Castle. He died on April 5th, 1895, in the
93rd year of his age.

James Dwieut Dana was born in Utica, New York, on February
12th, 1813, and was educated at Yale College, where he graduated
in 1833. On leaving Yale, he entered the service of the United
States Navy as teacher of mathematics to midshipmen. In this
capacity he visited, on board the ‘Delaware’ and the ‘ United
States,’ a number of the seaports of France, Italy, Greece, and
Turkey, the cruise lasting fifteen months.

In 1836 he became assistant to Prof. Benjamin Silliman, the
mineralogist, and in 1837 he published his ‘System of Mineralogy,’
a work which obtained a worldwide reputation, and which ran
through numerous editions, of which the last was issued in 1892.
Dana was next appointed Geologist to the Wilkes Exploring
Expedition, which sailed in 1838, and returned in 1842. The

Ix PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

expedition consisted of five ships, the route pursued being briefly
_as follows :—First to Madeira, then to Rio Janeiro, down the coast
and through the Straits of Magellan, after passing which, while on
board the ‘ Relief, he nearly suffered shipwreck off Noir Island, the
ship remaining for three days and nights in extreme peril; in the
same storm one of the smaller accompanying vessels was lost.
Thence they sailed to Chili, Peru, and across to the Paumotus, to
Tahiti, and the Navigator Islands; then to New South Wales,
_ where the naturalists remained while Commodore Wilkes went into
the Antarctic region; then to New Zealand and the Fiji Islands,
where two of the officers were murdered by the natives; thence to
the Sandwich Islands, the Kingsmill group, the Caroline Islands,
and north to the coast of Oregon. Here, near the mouth of the
Columbia river, the ‘ Peacock,’ the ship to which Dana had been
assigned, was wrecked, entailing the loss of all his personal effects,
as well as many of his collections. He then made one of the party
that crossed the mountains near Mount Shasta, and found their way
down the Sacramento river to San Francisco. In his report of the
expedition he states that the geological features indicated the
probable presence of gold. This was six years before the discovery
of gold in California, and rich mines have since been discovered in
the region over which the party went. At San Francisco they
were taken on board the ‘ Vincennes’ and the homeward voyage
was made by way of the Sandwich Islands, Singapore, the Cape of
Good Hope, and St. Helena, arriving in New York in June, 1842.
As a result of his connexion with the expedition he published the
Reports on Geology, Crustacea, and Zoophyta, and spent in all
thirteen years editing and superintending the printed reports
resulting from these voyages. In 1855 he succeeded to the Chair
of Mineralogy at Yale, a position which he held till 1894, when he
resigned. His ‘Manual of Geology’ appeared in 1863, a fourth
edition having beén issued only last year, 1895. He was part
editor of the ‘American Journal of Science’ from 1846, and con-
tinued his interest in it up to the last.

Dana received the Copley Medal from the Royal Society in 1877,
and the Wollaston Medal from the Geological Society in 1872; he
was a member of the Academy of Sciences, Paris, and of the
Academies of Berlin and Munich. Moreover, he was elected a
Foreign Member of the Royal Society in 1884, and of the Geological
Society in 1851.

His publications amount to nearly 400 in number, and when one

Vol. 52.) ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixi

considers that these include such colossal works as his ‘ Mineralogy ’
and his ‘Manual’ and ‘ Text-book of Geology,’ one is astonished at
Prof. Dana’s wonderful power of work, nor is one surprised to
learn that his health broke down upon several occasions owing to
his excessive mental labours. It is extremely touching to read of
Prof. Dana working on at the new edition of his ‘Manual of
Geology’ at the age of 82, and being actively assisted in all his
literary labours by his life-long companion with never-failing and
watchful care to the end.

It is impossible to do justice to this distinguished man and
personal friend in so short a notice, but we feel that, with our
American brethren, we have lost in him one of the greatest figures
in geology of our time. Prof. Dana died on’April 14th, 1895, in his
82nd year.

It is hardly credible that a man could have attained to so high
a position at once in zoology, in mineralogy, and in geology, and,
from the specialization now rendered necessary by the progress
of natural knowledge, we cannot expect to look upon his like
again, nor to see united in one man attainments so varied in
character as were those of the American veteran, James Dwight
Dana.

As a man, he was noted for the gentleness and kindness of his
character, so that he was always on excellent terms with all his
colleagues. He leaves a widow and four sons and daughters.

Mr. Josep Mircuett, Jun., Assoc.M.Inst.C.E., was born on
September 7th, 1840. He was distinguished as a colliery engi-
neer in the South Yorkshire district, several of the largest mines
in the Barnsley district having been either sunk or re-opened by
him. Among the latter may be noticed the Swaithe Main and
Edmund’s Main Oollieries, re-opened and put in order after ex-
plosions, and of the former the Mitchell Main Colliery. A more
important enterprise for the development of 2500 acres of the
Barnsley bed at Grimesthorpe was commenced about six months
before his death. Both as Secretary and President he contributed
largely to the development of the Midland Institute of Mining,

Civil, and Mechanical Engineers, and he was also very active —

in the formation of that most useful body, the Federated Insti-
tution of Mining Engineers. He was elected a Fellow of the
Geological Society in 1873. His death occurred on April 18th,
1895.

bai, PROCEEDINGS OF THE GEOLOGICAL society. | May 1896,

VaLentiInE Batt, C.B., M.A., and LL.D. (Dublin), F.B.S.,
M.R.1.A., Director of the National Museum at Dublin, was the
second son of the well-known naturalist, Dr. Robert Ball, who died
in 1857. His elder brother is Sir Robert Ball, of Cambridge, and
his younger brother is Dr. Charles B. Ball, of Merrion Square,
Dublin. Dr. Valentine Ball was born on July 14th, 1843, at No. 3
Granby Row, Dublin, a house well known in those days as a leading
centre of intellectual resort in that metropolis. He was educated
first at a private school by Dr. Brindley at Chester, and afterwards
by Dr. Benson, in the early days of Rathmines School.

Valentine Ball entered Trinity College in 1860, and about the
same time he was appointed by the later Master Fitzgibbon to a
clerkship in the office of the Examiner in Chancery. His University
career was not an eventful one in the academic sense, for the duties
of his office in the Four Courts did not leave him sufficient time for
more than obtaining an ordinary degree. A taste for scientific
pursuits was, however, so marked that in 1864, when he was
twenty-one years of age, he was appointed to the Geological Survey
of India, then under the direction of Dr. Thomas Oldham. Ball
felt that this would give him the opportunity which he wanted for
the study of nature in a wide field, and accordingly he went to
India. His duties as a geological surveyor often led him into very
unfrequented parts of our Oriental possessions, and frequently, for
many months together, he lived in camp in the jungle, apart from ;
all other Europeans. Wherever Ball travelled he utilized his oppor-
tunities to the utmost; indeed, throughout his life, his diligence
could hardly have been surpassed, and nothing worthy of notice
that came within his range was unobserved and unrecorded. It
was presently apparent that the young geological surveyor was not
only able to fulfil his duties in making a careful investigation of
the rocks and of their economic value, but that various other
branches of natural history were sedulously cultivated by him.

Steadily the reputation of the Indian geologist advanced in
scientific circles. He was elected a Fellow of the Calcutta Uni-
versity in 1872. He devoted a short vacation to extending his
travels to the Andaman and Nicobar Islands, and to visiting
Barren Island and Narcondam volcanoes in the Bay of Bengal,
which he described in the ‘ Geological Magazine,’ 1879, p. 16, pl.i.;
1888, p. 404; and 1893, p. 289, pl. xiii.

In 1874 Valentine Ball was elected a Fellow of the Geological
Society of London. His first important volume, ‘Jungle Life in

Wol. 52: ANNIVERSARY ADDRESS OF THE PRESIDENT. lxiil

India,’ gives a record of his travels and summarizes the results of
his numerous papers. This work was followed by an elaborate
treatise on the economic geology of India. His scientific reputation
had by this time become so firmly established that, on the resigna-
tion of the Chair of Geology in the University of Dublin by the
Rev. Dr. Haughton, Valentine Ball was appointed his successor.
Thus was brought to a close his connexion of seventeen years with
the Geological Survey of India.

In 1882 he was elected a Fellow of the Royal Society. In
September 1833, Ball was appointed Director of the Science and
Art Museum in Dublin, and resigned his Professorship in the
University for the coveted post of Custodian of the new Museum,
which he so ably and admirably organized, and to which he devoted
the remainder of his life with unsparing energy and zeal.

Though his death was premature, yet it may be said that he had
lived long enough to see the substantial completion of his life’s
task, the arrangement of the new Museum, which will long remain
as a testimony to his work.

The University of Dublin conferred on him the honorary degree
of Doctor of Laws, and by Her Majesty he was made a Companion
of the Bath. With most of the scientific societies of Dublin
Dr. Y. Ball was in intimate association.

In 1879, he married the eldest daughter of the late John Stewart
Moore, of Moyarget, Co. Antrim. He leaves a family of four young
children. For some years Dr. Ball’s health had been failing.
Towards the middle of June serious symptoms became apparent,
and he passed away peacefully on the afternoon of June 15th at his
residence, 28 Waterloo Road, Dublin.

The only communications which Valentine Ball made to the
Geological Society were ‘On the probable Mode of Transport of the
Fragments of Granite and other Rocks which are found embedded
in the Carboniferous Limestone of the neighbourhood of Dublin,’
Quart. Journ. Geol. Soc. vol. xliv. (1888) p. 3871; and ‘On some
Eroded Agate-pebbles from the Soudan,’ Quart. Journ. Geol. Soc.
vol. xliv. (1888) p. 368.

In the Right Hon. Tuomas Henry Hux ey, this Society has lost
one of its most distinguished Fellows, and the world of science one
of its brightest ornaments.

He was elected a Fellow in 1856, was placed upon the Council in
1858, and in the same year was chosen to be one of the Secretaries,

lxiv PROCEEDINGS OF THE GEOLOGICAL society. [| May 1896,

filling that office till 1862. In that year, owing to the absence from
England of the then President, Mr. Leonard Horner, Mr. Huxley
drew up and delivered the customary Anniversary Address. He was
a Vice-President in 1866; filled the office of President of the Society
in 1868-69, and was again a Vice-President in 1871.

His first paper was read before the Society as early as 1856, and
his last (on Hyperodapedon G'ordoni) on May 11th, 1887, a period
of 31 years, during which time he communicated 25 separate papers
and three Presidential Addresses.

In 1876 the Society awarded him the blue-ribbon of our science,
the Wollaston Medal.

Such is the record which Huxley has left us within these walls;
but the energies he possessed, and the genius which inspired him,
carried him into many other fields, and we cannot claim for our-
selves more than a share in the life-work of this gifted and brilliant
naturalist and scholar.

Thomas Henry Huxley was born at Ealing on May 4th, 1825,
and was for some years educated at the School in his native place,
where his father was one of the masters. This preparatory course
was followed by assiduous private reading, including German scientific
literature, and instruction in medicine received from a brother-in-
law, who was a physician. He afterwards attended lectures at the
Medical School of the Charing Cross Hospital. In 1845 he passed
the first M.B. examination at the University of London, taking
honours in anatomy and physiology. Even before this he had
given evidence that his mind was occupied with something more
than the technical details of the medical profession, for, while yet a
student at Charing Cross Hospital, he had sent a brief notice to the
‘Medical Times and Gazette’ of that layer in the root-sheath of hair
which has since borne the name of Huxley’s Layer. After devoting
himself for a short time to the practice of his profession among the
poor of London, he, in 1846, joined the medical service of the Royal
Navy, and was sent to Haslar Hospital. Here he did not remain
long, but, like so many other men who have made their mark in
biological science, set out on a voyage round the world.

Through the influence of the distinguished naturalist, Sir John
Richardson, who had accompanied Franklin in his early Arctic
expeditions, young Huxley obtained the post of assistant-surgeon
on Her Majesty’s ship Rattlesnake, then about to proceed on a
surveying voyage to the Southern Seas. ‘The ship sailed from
England in the winter of 1846, and did not return until November,

Wols 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. lxv

1850. During the greater part of that time the Rattlesnake was
employed in surveying the eastern and northern coasts of Australia
and the coast of New Guinea. The seas lying between the Great
Barrier Reef and the coast of the mainland were of special interest
to the naturalist. Huxley took ample advantage of his opportunities
to study the fauna of the seas which he traversed, with the results _
known to all naturalists. The communications which he sent home
during the voyage made his name well known to the scientific world
even before his return. Several of these were published in the
‘Philosophical Transactions’ of the Royal Society, and it is in-
teresting to note that his first paper was presented to the Society
by the then Bishop of Norwich (father of Capt. Owen Stanley, R.N.,
who commanded the Rattlesnake), and read June 21st, 1849:
‘On the Anatomy and Affinities of the Medusz.’ Huxley in vain
endeavoured to obtain the publication by the Government of a part
of the work done during his voyage, and it was not until 1859 that
his great work, entitled ‘Oceanic Hydrozoa, a description of the
Calycophoride and Physophoride observed during the voyage of
Her Majesty’s ship Rattlesnake, was given to the world.

The reputation which he had already attained at the early age of
26 is evident from the fact that in the year after his return, 1851,
he was elected a Fellow of the Royal Society, and in 1852 was
awarded one of the Society’s Royal medals. In 1853 he left the
Naval Service, and the following year, on the removal of Edward
Forbes from the Royal School of Mines to the Chair of Natural
History in Hdinburgh, Huxley was appointed Professor of Natural
History, including Paleontology, in that institution, a post which
he held until his retirement at the age of 60—an age at which, as he
was wont to assert, every scientific man ought to commit the happy
despatch. In the same year, 1854, he was appointed Fullerian
Professor of Physiology to the Royal Institution and Examiner in
Physiology and Comparative Anatomy to the University of London.
Other posts and honours crowded thick upon him. From 1863 to
1869 he held the Chair of Hunterian Professor at the Royal College
of Surgeons. In 1862 he was President of the Biological Section
at the Cambridge Meeting of the British Association, and eight years
later held the Presidency of the Association at the Liverpool Meet-
ing. In 1869 and 1870 he was President of the Geological and
Ethnological Societies. As might be expected, Prof. Huxley held
strong and well-defined views on the subject of education. He was
a man who at all times had a keen sense of public duty, and it was

Ixvi PROCEEDINGS OF THE GEOLOGICAL SocIETY. [May 1896,

this which induced him to seek election on the first London School
Board in 1870. TIll-health compelled him to retire from that post
in 1872, but during his period of service as Chairman of the
Education Committee he did much to mould the scheme of education
adopted in the Board Schools.

He was elected Secretary of the Royal Society in 1873, and ten
years later was called to the highest honorary position which an
English scientific man can fill, the Presidency of that Society.
During the absence of the late Prof. Sir Wyville Thomson with
the ‘Challenger’ Expedition, Huxley, in 1875 and 1876, took his
place as Professor of Natural History in the University of Edinburgh.
From 1881 to 1885 he acted as Inspector of Salmon Fisheries.
But this and all his other official posts he resigned in 1885, shortly
after which he removed to Eastbourne.

During the 34 years that elapsed between his return from the
‘Rattlesnake’ voyage and his retirement from his various official
posts, Huxley’s activity as an investigator, as a writer, as a lecturer,
as a citizen of London and of England, and as a man of healthy
social instincts was incessant. There is hardly a department in the
wide field of zoology, in its most comprehensive sense, in which he
has not done original work. Huxley’s investigations have explained
many difficult problems in the mechanism of men and animals. So
far as the character of his work is concerned, he is to be compared
rather with Owen than with Darwin; though not only was the quality
of his work more solid and enduring, but in many ways his type of
mind was essentially different from that of Owen, more liberal, more
open, free from what may perhaps be called the pettiness which
hampered Owen’s scientific vision. Huxley’s investigations, it may
fairly be said, especially after the publication of the ‘ Origin of Species,’
were to a large extent guided by the Darwinian theory, and the results
may be regarded as among the most substantial confirmations and
illustrations of the doctrine of evolution as propounded by Darwin.

In the year before the publication of the ‘ Origin’ he chose as
the subject of his Royal Society Croonian Lecture ‘The Theory of
the Vertebrate Skull,’ in which, so high an authority as Prof.
Heeckel assures us, he first opened out the right track to a solution
of a perplexing problem. Much of Huxley’s technical work was
published through the Royal Society, the Geological Survey, the
Geological Society, and other media familiar to specialists, but seldom
consulted—even by the educated general public. To give a mere list
of these many memoirs would serve no purpose. Such important

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixvil

subjects are dealt with as the Evolution of the Crocodilia, the Classi-
fication of Birds, the Dinosauria, Fossil Fishes, Glyptodon, the
Affinity between Reptiles and Birds, Ceratodus, the Cranial and
Dental Structure of the Canide, Reproduction and Morphology of
Aphis, the Development of Pyrosoma. These few from among the
titles of many memoirs will suffice to show that Huxley’s special
researches deal with the history and structure of animals of many
types, and that by themselves they would justify the verdict of
Ernst Heckel that Huxley was the first zoologist among his
countrymen. In this connexion may be mentioned his ‘ Manual of
the Invertebrata,’ his ‘ Lessons in Elementary Physiology,’ and
other text-books. ‘When we consider the long series of distin-
guished memoirs with which,’ to quote Heckel, ‘ Prof. Huxley
has enriched zoological literature, we find that in each of the
larger divisions of the animal kingdom we are indebted to him
for important discoveries..... More important than any of the
individual discoveries which are contained in Huxley’s numerous
less and greater researches on the most widely different animals,
are the profound and truly philosophical conceptions which have
guided him in his enquiries, have always enabled him to distinguish
the essential from the unessential, and to value special empirical
facts chiefly as a means of arriving at general ideas.’

Huxley had a power of popular exposition almost unequalled.
He could make plain, even to an ordinary working-man audience,
the bearings of the most recondite researches of the zoologist and
botanist; witness his famous Norwich lecture ‘On a Piece of
Chalk, and the memorable sermon which he gave on a Sunday
evening a quarter of a century ago in the midst of shocked
Edinburgh. But it is not only to the ordinary intelligent reader
that his numerous lectures, addresses, and magazine articles appeal.
It is to these in their collected form that the special enquirer must
go to find the broad results of Huxley’s arduous scientific investi-
gations. It was his duty when first he assumed his post in the
School of Mines to give a course of lectures every alternate year to
working men; and it was through this channel that he first
made known his remarkable discussion on ‘ Man’s Place in Nature.’
‘This was one of the earliest and one of the most striking results of
the publication of the Darwinian theory, for it was given to the
world some ten years before the issue of Darwin’s ‘ Descent of
Man.’ Even by those who maintain that influences have been at
work in the development of Man, additional to those which have

Ixviii PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

been common to him and the lower animals, it may be said that
Huzxley’s conclusions as to the intimate relations between humanity
and the higher apes have been generally accepted. It was in the
same ‘popular’ form that Huxley gave to the world many other
theories and disquisitions which have had much to do with moulding
educated opinion during the last quarter of a century. Thus in
his three addresses as President of the Geological Society: on
‘Geological Contemporaneity and Persistent Types of Life,’ on
‘Geological Reform, and on ‘ Paleontology and the Doctrine of
Evolution,’ he dealt in his characteristically clear and masterly
manner with problems that still agitate evolutionists—the imper-
fection of the record, the duration of geological time, the succession
of life on the face of the earth, and other matters of profound
interest to geologists and biologists. In his papers on ‘The
Methods and Results of Ethnology’ and on ‘Some Fixed Points
in British Ethnology’ he introduced into the somewhat chaotic
branch of investigation that deals with Man a simplicity of treat-
ment and a scientific method which have done much to raise it
above a mere collection of unrelated facts. The lectures delivered
in America in 1876 brought together the data as to the evolution
of the Horse with a cogency that forms one of the most telling
arguments in favour of the Darwinian hypothesis.

The only posts which Huxley continued to fill up to the time of his
death were those of Dean and Honorary Professor of Biology in the
Royal College of Science, South Kensington, Trustee of the British
Museum, and President of the Paleontographical Society of London.

In 1892 he was admitted a member of the Privy Council, having
previously refused the honour of knighthood.

It is impossible to enumerate here the many honours conferred
upon Prof. Huxley. He was made a Doctor of the Universities
of Edinburgh, Dublin, Cambridge, Oxford, Breslau, and Wurzburg.
The Academies of Brussels, Stockholm, Copenhagen, Cairo, Berlin,
Gottingen, Haarlem, St. Petersburg, Lisbon, Rome, Munich, Phila-
delphia, and many others, conferred on him their diplomas. He
was made an Honorary Fellow of the Royal Society of Edinburgh ;
a Member of the Royal Irish Academy ; of the American Academy
of Science ; and (in 1879) a Corresponding Member of the Institute
of France (Section Anatomy and Zoology, in place of Von Baer).
He was also a Knight of the Polar Star of Sweden.

Turning to his published works, we may refer to his ‘ Oceanic
Hydrozoa’; his ‘Lectures on Comparative Anatomy and Physiology’ ;

Vol. 52. ] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixix

‘ Lessons in Elementary Physiology ’ (1866), and many subsequent
editions ; ‘ An Introduction to the Classification of Animals ’ (1869) ;
‘Lay Sermons, Addresses, and Reviews’ (1870). His text-books
on the Anatomy (I.) of the Vertebrata (1871) and (II.) of the
Invertebrata ; his ‘ Practical Biology’; ‘ Man’s Place in Nature’;
his works on the Crayfish, and on Physiography, well illustrate the
wide extent and versatility of his powers, both as a naturalist and
author ; but it was by his lectures and addresses that he displayed
the most marvellous of his intellectual gifts, and produced the
greatest effect upon the science of his time. He had that wonderful
power of carrying his audience along with him, and the happy
facility of bringing his knowledge within the mental grasp of his
hearers.

Of the 144 papers attributed to Prof. Huxley in the Royal
Society’s list of scientific papers extending from 1847 to 1884, the
following may be mentioned as directly connected with our own
science :—

On the Method of Paleontology (Annals, 1856). —Pygocephalus Cooperi, a Coal-
measure Crustacean (Q. J. G. S. 1857). On the genus Pteraspis (Brit. Assoc. Rep.
1858). On Cephalaspis and Pteraspis (Q. J. G. S. 1858). On Plesiosaurus
Etheridgei (Q. J. G.S. 1858). On Persistent Types of Animal Life (Roy. Inst.
Proc. 1858-62). On Species and Races and their Origin (Roy. Inst. Proc. 1860).
On Stagonolepis Robertsoni (Q. J.G.S. 1859). Onsome Amphibian and Reptilian
Remains from South Africa and Australia (Q. J. G. S. 1859). On Dicynodon
Murrayi, South Africa, and on Skulls of Dicynodonts (Q. J. G. S. 1859). On
Rhamphorhynchus Bucklandi, a Pterosaurian from Stonesfield (Q. J. G. S. 1859).
On a Fossil Bird and a Fossil Cetacean from New Zealand (Q. J. G.S. 1859). On
Dermal Armour of Crocodilus Hastingsie (Q. J. G.S. 1859). On the Anatomy of
Pterygotus (Geol. Surv. Mem. 1859). On Dasyceps Bucklandi (Geol. Surv. Mem.
1859). On the Lower Jaw of a Labyrinthodont (Geol. Surv. Mem. 1859). On
Macrauchenia boliviensis (Q. J. G.S. 1861). On Pteraspis dunensis (Q. J.G.S.
1861). Systematic Arrangement of Devonian Fishes (Geol. Surv. Mem.1861). New
Labyrinthodonts from Edinburgh Coal-field (Q. J. G.S. 1862). On a Stalk-eyed .
Crustacean from the Coal-measures, Paisley (Q. J. G.S. 1862). Onthe Premolar Teeth
of Diprotodon (Q. J. G.S. 1862). Ona New Species of Glyptodon (Roy. Soc. Proc.
1862-63). Anthracosaurus Russelli, Coal-field, Lanark (Q. J. G. S. 1863). On
Cetacean Fossils termed ‘ Ziphius, Cuvier, from the Red Crag (Q. J. G. S. 1864).
Osteology of Glyptodon (Phil. Trans. 1865). Vertebrate Remains from Jarrow
Colliery, Kilkenny, Ireland (Geol. Mag. 1866). Dinosaurian Reptiles from South
Africa (Q. J. G. 8. 1867). On Acanthopholis horridus, anew Reptile from the Chalk
Marl (Geol. Mag. 1867). New Specimen of Telerpeton elginense (Q. J. G. S. 1867).
Animals intermediate between Birds and Reptiles (Geol. Mag. 1868). Two new
Fossil Lacertilians from South Africa (Geol. Mag. 1868, pp. 201-205). On Archeo-
pteryx lithographica (Roy. Soc. Proc. 1868). On Hyperodapedon (Q. J. G. S.
1869). On a new Labyrinthodont, Pholiderpeton scutigerum, from Bradford
(Q. J. G. S. 1869). Onthe Upper Jaw of Megalosaurus (Q. J. G. S. 1869). Prin-
ciples and Methods of Palzontology (Smithsonian Reports, 1869). The Milk-
Dentition of Paleotherium magnum (Geol. Mag. 1870). On Hypsilophodon Foxii,
a new Dinosaurian from the Wealden, Isle of Wight (Q. J. G.S. 1870). Further

VOL. LII.

lxx PROCEEDINGS OF THE GEOLOGICAL socrETy. [May 1806,

Evidence of the Affinity between the Dinosaurian Reptiles and Birds (Q. J. G.S.
1870). On the Classification of the Dinosauria, with Observations on the Dinosauria
of the Trias (Q. J. G. S. 1870). Triassic Dinosauria (‘ Nature,’ 1870, p. 23). On the
Maxille of Megalosaurus (Phil. Mag. 1870). (With Dr. E. P. Wright) On the
Fossil Vertebrata from the Jarrow Colliery, Kilkenny, Ireland (Roy. Irish Acad.
Trans. 1871). On Stagonolepis Robertsoni, etc. (Q.J.G.S. 1875). On the Evidence
as to the Origin of existing Vertebrate Animals (lectures, ‘ Nature,’ 1876). The Rise
and Progress of Paleontology (‘Nature,’ no. 24, 1881). The Coming-of-age of
the ‘Origin of Species’ (1880, Roy. Inst. Proc. 9, 1882).

It may be truly said of Huxley that, although an antagonist to be
feared, and a vigorous hater of all shams, he was also a warm-
hearted and staunch friend, and one who never forgot a service
rendered to him. The influence of his writings and his scientific
labours will long outlive the memory of those who now mourn >
his loss.

CuaRLes CARDALE Basineton, M.A., F.R.S., Fellow of St. John’s
College, Cambridge, was born on November 23rd, 1808, at Ludlow.
He was a student at St. John’s College, Cambridge, and graduated
in 1832. In 1861 he succeeded Prof. Henslow in the Chair of
Botany at the University. He retained his professorship until
his death, on July 22nd, 1895, but for the later years of his life
ceased to take an. active part in the work of the Botanical School.
Prof. Babington attained to the highest position as a critical
British botanist, having an intimate and accurate acquaintance
with the flora:of our islands, and was the first to carefully correlate
it with that of Europe.*

The best testimony of the value of his work is the fact that his
. *Flora’ has passed through eight editions in his lifetime, and still
remains a standard work. In fossil botany his only contributions
are the determination of some plants from the peat of Cambridge-
shire.

He: published ‘ A History of the Chapel of St. John’s College,
Cambridge,’ and contributed many papers to the publications of
the Cambridge Antiquarian and other Societies.

He was elected a Fellow of the Geological Society in 1835, fie
never contributed any paper to its Quarterly Journal.

THomas JAMES SLATTER, whose decease we have now to record,
died at his house, ‘The Drift,’ Evesham, on August Ist, 1895, in
his 61st year.. He was a geologist whose knowledge of the locality

1 See Babington’s ‘ Manual of British aie ai ’; the first edition appeared
in 18438, and the eighth in 1881.

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. xx

in which he lived and worked was most intimate and reliable. He
was born at Gloucester in 1834, while his family was for many
years located at Stratton, near Cirencester. He was the cousin and
intimate friend of John Jones, of Gloucester, whose contributions to
geological literature are well known. Mr. Slatter commenced his
business life, when quite a young man, in the Gloucestershire Bank,
and then took up his abode at Evesham. He became successively
manager of the Moreton-in-the-Marsh, Redditch, and Evesham
branches of the Bank, but retired into private life a few years
since, and, having erected a house on Green Hill, near Evesham,
he removed thither his extensive and most interesting collection
of Liassic fossils. In 1879 he became a Fellow of the Geological
Society, but, to the regret of those who knew how careful an
observer he was, he never became the author of any work on
geology, nor even of any contribution to a periodical on the geology
of the district which he knew so well.

Grorere Francis Hosxine, who resided at Bendigo, Otago, New
Zealand, was elected a Fellow in 1891. He died at Dunedin,
New Zealand, August 18th, 1895. He had not contributed any
paper to the Society.

By the death of Mr. Jamzs Carter, F.R.C.S., which took place
at Cambridge on August 31st, 1895, in his 82nd year, one of the
few remaining links which connected the days of Sedgwick with
those of the modern school of geology in Cambridge has been
broken. During the greater part of his life Mr. Carter practised
as a surgeon in Cambridge, where his house, in Petty Cury, was for
many years the resort of the leading geologists and men of science
in the University, who never failed to find in Mr. and Mrs. Carter
genial, cultivated, and hospitable hosts.

Mr. Carter was especially interested in paleontology, and devoted
much of his time to this and other scientific subjects. He contri-
buted papers to the Geological Magazine and the Quarterly Journal
of the Geological Society, the chief being ‘On a New Species of
Ichthyosaurus from the Chalk,’ ‘On Orithopsis Bonneyi,* ‘On
a Skull of Bos primigenws perforated by a Stone Celt,’® ‘On the

1 Brit. Assoc. Reports, 1845 (1846), Sec. p. 60, and Lond. Geol. Journ. 1846,
vol. i. p. 8, woodcut. .

2 Geol. Mag. 1872, pl. xiii. f. 1, p. 529.

3 Geol. Mag. 1874, p. 492.

f2

Ixxii PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 18096,

Decapod Crustaceans of the Oxford Clay,’ ' and ‘ On Fossil Isopods,
with a Description of a New Species.’ ”

Mr. Carter was recognized as an authority on the fossil Podo-
phthalmatous Crustacea, and had for some time been engaged in
collecting materials for a monograph on that group; he has left
his manuscript in an advanced state. He retained his interest in
his pursuits almost till the last, and was engaged in his scientific
work to within a few weeks of his death. He was elected a Fellow
of the Geological Society in 1877. He served on the Councils of
the Geological and Palzontographical Societies for some years,
and was a local secretary of the latter society.

Mr. Carter presented his collection of Cambridge fossils to the
Woodwaidian Museum some years before his death.

Sven Lovin, the eminent Swedish biologist, died at Stockholm,
September 3rd, 1895. He was born in the same city on January
6th, 1809; his father was a wealthy merchant, who provided his.
son with an excellent education, the higher stages of which were
carried on partly in the University of Upsala, and subsequently in
that of Lund, where Lovén, in 1829, took the degree of Doctor of
Philosophy. In the following year he studied zoology at Berlin
under such teachers as Ehrenberg and Rudolphi, and then returned.
to Lund as Docent in Zoology. Several succeeding years were
almost exclusively spent in studying the marine fauna, and more
particularly the mollusca, of the western coasts of Sweden, and the
field of his investigations was afterwards extended to the shores of
the northern part of Norway and Finmark.

In 1837 Lovén sailed to Spitzbergen and inaugurated the first of
the Swedish scientific expeditions to that island. Though his
observations were mainly directed to the marine fauna of this
region, the geological phenomena did not escape his observation,
and he was the first to discover the Carboniferous strata of the
island. He also obtained fossils from newer rocks, which proved to
be in part identical with those from the Jurassic beds of Petchora
Land, described by Keyserling, and thus established the existence
of Jurassic deposits in Spitzbergen.

In 1839 Lovén supplemented his study of the molluscan fauna
of the Arctic regions by visits to the Museums of London, Paris,
and the principal towns of Germany. He thus fitted himself for
the position of Intendant or Keeper of the Lower Invertebrata in

1 Quart. Journ. Geol. Soc. vol. xlii. (1886) p. 542, pl. xvi.
2 Geol. Mag. 1889, p. 193, pl. vi. figs. 1-7.

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxili

the Swedish State Museum, with the associated title of Professor
to the Academy of Sciences, to which he was appointed in 1841.
He fulfilled the duties of this office for the long period of 51 years,
retiring in 1892, when the natural infirmities of age disabled him
from further service. One of the duties assigned to the Intendants
of the Museum was the preparation of an annual report, including
a record of the general progress in the particular branch of
science to which each belonged ; in doing this Lovén brought out a
fairly complete report of the zoological and palzontological litera-
ture of the Lower Invertebrata for the years 1840-49, in three
thick volumes. The great increase of scientific literature after this
latter date would have needed all the time of the Intendant to keep
a proper record of it, and therefore the obligation was abolished.

Lovén’s repeated journeys across Sweden by way of the Gota canal,
from Stockholm to Bohuslin on the west coast, gave him an oppor-
tunity of studying the geology of the country, and so intimately
was he acquainted with it that (on Berzelius’s recommendation) he
accompanied Sir Roderick Murchison from Goteborg to Stockholm,
bringing under his notice the best known Silurian localities in
Eastern and Western Gotland. The friendship then formed was
pleasantly renewed some ten years later, when he met Murchison
and the late Prof. John Morris at Marienbad.

The critical knowledge possessed by Lovén of the Mollusca of the
Arctic and North Seas enabled him to recognize the distinctly
Arctic character of the shells in the Glacial deposits of Sweden,
now elevated considerably above the sea-level. He first pointed
out, in 1839, this evidence of the former presence of an ice-cold sea
over parts of Sweden. Later on, in 1860, he published several
papers on certain Crustacea and fishes, now living in the larger
inland lakes of Sweden, which were shown to be the descendants’
of forms inhabiting Arctic seas, constituting a relict-fauna which
had thus survived the changes of habitat and climate.

Lovén’s researches on the Mollusca continued up to 1860; from
then onwards to the close of his career, a period of over 30 years,
his energies were devoted to the study of Echinodermata. His
renown as a biologist will mainly rest on his magnificent work on
the Echinoidea, as shown in the two principal memoirs ‘ Etudes sur
les Echinoides,’ published in 1874, and ‘ On Pourtalesia, a genus of
Echinoidea,’ in 1883. Among the authors who have most clearly
illustrated the developmental history and the organic relations ot
the Echinoidea, Sven Lovén will stand in the foremost rank.

From his early days Lovén recognized the intimate reciprocal

xxiv PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

connexion of zoology and paleontology ; this standpoint was steadily
followed in his great work on the Kchinoids, and he gave a practical
expression of his views on this subject by arranging the fossil and
recent representatives of this group side by side on the same shelves
in the State Museum at Stockholm.

Both in his own country and abroad, Lovén was honoured as a
master in natural-history research, and his amiable character and
personal kindness endeared him to his colleagues and fellow-
Academicians in Stockholm. He was chosen a Corresponding
Member of the Institute of France in 1872, a Foreign Correspondent
of the Geological Society in 1863, and a Foreign Member in 1882.
He was further a Foreign Member of the Royal Society, and of
the Academies of Berlin and Vienna. And lastly, in 1893, he
received the Prussian Order ‘ Pour le Mérite.’* (G. J. H.)

The Hon. Watrer Batpock Durrant Manrett was the eldest
son of Dr. Gideon Mantell, F.R.S., F.G.8., the well-known Sussex
geologist and discoverer of the Jguanodon. He was born in
1820, and left England about 1840 for New Zealand, where he
became a man of great public importance, holding the posts of
Minister for Native Affairs, Postmaster-General, and Secretary for
Crown Lands. He was ever mindful of the interests of the Maoris,
and sought to serve them to the utmost of his power.

In 1847 Mr. Mantell sent home the first remains of WVotornis.
These were described by Owen as belonging to an extinct form,
but two years later, in 1849, Mantell obtained from some sealers
on the south coast of Middle Island (now called the South Island),
where he was Government Commissioner for the Settlement of
Native Claims), a skin together with the skull and some limb-bones

‘of a Notornis recently hunted down with dogs, and killed and eaten
by these men. Not long afterwards another smaller skin was
obtained. Both these specimens are preserved in the Natural
History Museum.

The bird was apparently unknown to the Maoris, but there are
traditions of a ‘Swamp-Hen,’ called on the North Island ‘ Moho,”
and in the South ‘ Takahé,’ which may have been the Wotorms.

In 1868 Mantell read a paper before the New Zealand Institute *

1 For many of the data in the above notice the writer is indebted to the
sympathetic notice of his late colleague by Prof. G. Lindstrom in Geol. Foren.
i Stockholm Forhandl. Bd. 17, Haft 6, 1895, pp. 627-638.

2 Trans. New Zealand Institute, vol. i. 1868.

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxv

‘On the Moa,’ in which he insisted that these birds were con-
temporaries of Man, their remains being found charred and broken
in the Maori ovens, together with stone implements. He also
discussed the cause of the extinction of the Moa, and ascribed it
chiefly to the agency of man, a view now generally accepted.

In a later paper read before the Wellington Philosophical Society,
1872, he discussed statements that had been made, that Moa-bones
had been found beneath marine deposits with extinct shells, and
stated that this idea arose from a misapprehension of some informa-
tion supplied by him to his father, who employed it in his paper
before the Geological Society." He also gave an account of some
new localities in which Moa-remains had been found, including
Waikonaiti and Te-Rangatapu. In the latter he obtained a large
number of fragments of Moa-eggs, several of which he succeeded in
restoring. Some of these specimens are now in the Natural
History Museum.’

Mr. Mantell was elected a Fellow of the Geological Society in
1858. He died on September 7th, 1895, at the age of 75 years.
He was in correspondence with Sir William Flower, at the time of
his death, as to a further donation of his remaining private collec-
tion of Moa-remains to the British Museum, which it is hoped may
still be made by his representatives at Wellington, New Zealand.

Ricuarp Carrer, elected a Fellow in 1874, died on September
26th, 1895, aged 78, at Springbank, Harrogate, Yorkshire.

JouHn Extor Taytor, Ph.D., F.L.S.—As an enthusiastic lover of
Nature, and a popular exponent of geological and botanical science,
Dr. Taylor did much to arouse in others an interest in natural-
history subjects. The son of the foreman of a cotton factory, he
was born at Levenshulme, Manchester, September 21st, 1835, and
was employed in early years in the railway-works at Crewe.
Developing a taste for literature and science, he read largely,
cultivated a facile style of writing, and became a contributor to a
Manchester paper. His leisure hours were devoted to geology,

1 See Quart. Journ. Geol. Soc. vol. iv. (1848) pp. 225-241. [The woodcut
which gave rise to the misapprehension is probably that on p. 240.]

2 See ‘ Notice of the Remains of Dinornis and other Birds, and of fossils and
Rock-specimens, recently collected by Mr. Walter Mantell in the Middle Island
of New Zealand. By G. A. Mantell. With Notes by HE. Forbes, and Sketch-map
and Notes by Walter Mantell.’ Quart. Journ. Geol. Soc vol. vi. (1850) p. 819.

lxxvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

and in his first work, ‘Geological Essays’ (1864), he gave a sketch
of the geology of Manchester and its neighbourhood. About the
year 1862 he settled in Norwich, as sub-editor of the ‘ Norwich
Mercury,’ and stirred up much interest in the geology of the country
round the old city. He drew attention to the disturbed Chalk at
Whitlingham, Swainsthorpe, and other places; he pointed out the
differences in the Mollusca preserved in the two shell-beds in the
Norwich Crag at Bramerton ; and, in conjunction with the late
John Gunn, he established the Norwich Geological Society, which
is now incorporated with the Norfolk Naturalists’ Society. Before
these local societies, and the British Association, the results of his
geological observations were chiefly brought; and records of his
work are printed in the earlier volumes of the Geological Magazine.
In 1866 he published a little introduction to geology, entitled
* Lithographs,’ and subsequently other popular works on natural
history flowed from his pen. In 1872 he was appointed Curator
to the Ipswich Museum, a post from which he retired through
ill-health about two years ago. He contributed a capital ‘ Sketch
of the Geology of Suffolk’ to White’s History of the county. For
many years he was editor of ‘Science Gossip’; while his science
lectures at Ipswich and elsewhere were widely appreciated. Of
late years he was a strong advocate of the search for coal in East
Anglia. Dr. J. E. Taylor was present in the Geological Section of the
British Association at Ipswich in September last, and spoke on the
subject of the deep boring in search of coal at Stutton. He then
definitely stated his opinion that, although unfavourable to the anti-
cipations and hopes of himself and others, the boring had brought
up a sample of the Yoredale Shales below the real Coal-measures.
He died at Ipswich on September 28th, 1895.

The Rev. Epwarp Duxs, M.A., J.P., was elected a Fellow of
the Geological Society in 1856. He was author of a book entitled
‘Beneath the Surface, or Physical Truths, especially Geological.’
He died at Lake House, near Salisbury, on Oct. 17th, 1895.

In Senor Don Antonio pret Oasrtinxio, Director of the National
School of Engineers, and of the Geological Survey of Mexico,
America has lost a most able geologist, and the Geological Society
a distinguished Foreign Correspondent. He was the author of a
descriptive ‘Catalogue of the Iron and Stone Meteorites of Mexico’
(&vo, Paris, 1885), ‘The Fossil Fauna of the Sierra de Catorce, San

|
;
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Wel 52] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxvil

Luis Potosi’ (see Geol. Mag. 1895, p. 522), the ‘ Antropologia
Mexicana,’ ‘El Hombre del Pefion’ (Mexico, 1885, 8vo), also of
numerous other memoirs and a large number of excellent geological
maps. He died in Mexico city on October 22nd, 1895. He was in
England at the Meeting of the International Geological Congress
in 1888, and Commissioner for Mexico at the International Mining
and Metallurgical Exhibition at the Crystal Palace, Sydenham.
He was elected a Foreign Correspondent in 1891.

Pair Henry Lawrence was born in Liverpool in 1822, and
was admitted as a solicitor in 1848. He took an active part
in forming the Commons Preservation Society, and acted as its
solicitor until he ceased to practise in that branch of the profession.
In 1872 Mr. Lawrence was called to the Bar at Lincoln’s Inn. He
had been elected a Fellow of the Geological Society in 1866.

He was the translator of Bernard von Cotta’s ‘ Lithology,’ a
well-known handbook on rocks. Mr. Lawrence died at 8 Royal
Crescent, Brighton, on October 17th, 1895.

Captain Cuartes Tyter, F.L.S., was born in London in August
1826, and was educated at University College.

He was a man of scientific tastes, an ardent microscopist, and a
member of many learned societies. He joined the Microscopical
Society in 1858, was elected a Fellow of the Linnean Society in
1862, and of the Geological Society in 1863. He served for many
years on the Councils of the Paleontographical and the Ray Societies,
and was for some time a member of the Honourable Corps of
Gentlemen-at-Arms.

Capt. Tyler gave valuable assistance to Dr. Bowerbank in the
examination of exotic sponges, when he was preparing his Monograph
on the British Spongide for publication. He formed a large collec-
tion of fossils, and possessed many microscopes and a valuable
collection of slides.

One of the chief interests of his life was his connexion with the
Orphan Working School, Haverstock Hill, to which he devoted
himself with characteristic energy and close personal attention
during nearly forty years. During his later years he gave much
attention to the administration of St. Thomas’s Hospital, where he
served repeated terms of office as Almoner.

Capt. Charles Tyler, who was in the 70th year of his age, died on
November 2nd, 1895, after a short illness, which, however, was the
climax of a long period of failing health.

-

Ixxvlii PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

EK. A. Winscu was one of the original members of the Glasgow

Geological Society, which was founded in 1858, and served the

office of Vice-President several times from 1858 to 1881, when he
left Glasgow to reside at Carharrack, Scorrier, Cornwall... There
he died on November 19th, 1895, aged 73 years. He was elected a
Fellow of the Geological Society in 1875. '

The most important service which he rendered to geological
science was his discovery in 1865 of erect trees buried in volcanic
ash in Arran. These trees were discovered in the Lower Car-
boniferous strata of the north-eastern part of Arran, in the sea-cliff,
about 5 miles north of Corrie, near the village of Laggan. Here
strata of volcanic ash occur, forming a solid rock cemented by
carbonate of lime and enveloping trunks of trees, determined by
Mr. Binney to belong to the genera Sigzllaria and Lepidodendron.
Sir Charles Lyell mentions that he visited the spot in company
with Mr. Winsch in 1870, and saw that the trees with their roots,
of which about fourteen had been observed, occur at two distinct
levels in volcanic tuffs, parallel to each other, and inclined at an
angle of about 40°, having between them beds of shale and coaly
matter 7 feet thick. Itis evident that the trees were overwhelmed
by a shower of ashes from some neighbouring volcanic vent, just
as Pompeii was buried by matter ejected from Vesuvius.!

Mr. Wiusch writes*:—‘ Trunks of trees 18 to 24 inches in
diameter, and 2 to 3 feet in height, standing erect upon the
original beds of thin coal and shale upon which they grew, and
covered by layers of ash 2 to 3 feet in thickness, are found
regularly dispersed over the area: while the ash overlying them,
in which they are embedded, contains numerous branches, from 4
inches in diameter down to the minutest dimensions, some of the
impressions displaying an almost feathery foliage, as though sud-
denly covered up before the vegetation had had time to decay, or
become waterworn. The larger branches remain perfectly round,
and show the pith in an admirable state of preservation ; and the
cellular tissue, filled up with mineral matter, is plainly visible to
the naked eye.’

His last paper was ‘On a Logan-stone in the course of forma-
tion at St. Michael’s Mount,’ Trans. Roy. Geol. Soc. Cornw. 1895,
pp. 605 & 669.

1 Lyell’s ‘ Student’s Elements,’ 4th ed. 1885, pp. 496-497.
2 Geol. Mag. 1865, pp. 474-475 ; ibed. 1867, pp. 551-552.

|
|

Nol. i52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxix

Prof. Dr. Lupwie Rwrimeyer, Foreign Member of the Geolo-
gical Society of London, was born at Biglen in the Commenthal,
Canton Bern, in 1825. His father was a parish clergyman
and afterwards Superintendent of the Orphanage at Bonn. Lud-
wig was educated in the High School and Gymnasium of that
town, and in 1842 went to the University of Bern, where
he studied theology, with the intention of following his father’s
profession. Having developed a taste for comparative anatomy, no
doubt partly through the influence of his friend Peter Merian, the
Basel paleontologist, he forsook his theological studies, and took up
medicine. Afterwards he visited many of the chief European
cities, and in Paris in 1850 he became acquainted with Elie de
Beaumont. In 1852 he came to London, which he again visited
in 1877. In 1854 he took up academical teaching in the Bern
University, but in the following year he accepted the newly-
established Chair of Zoology and Comparative Anatomy at Basel,
which he held till his death.

On the occasion of his second visit to London he spent some weeks
in a critical examination of the fossil Bovide from the Older Pliocene
of the Siwalik Hills, India, part of the Falconer and Cautley Col-
lection, preserved in the British Museum.

His first work, ‘ Vom Meere bis nach den Alpen,’ was published
on his return from his travels in 1854; after this he issued a long
series of memoirs, characterized by the great accuracy and detail of
their observations, and the wide philosophical grasp and far-reaching
deductions made from them.

Some of the more important of these memoirs are :—‘ Unter-
suchungen der Thierreste aus den Pfahlbauten in der Schweiz,’
1860, in which he gives an account of the earlier races of some of
the domestic animals, and shows that while in the Lake-dwellings
of the Stone Age the remains of wild animals predominate (proving
that the inhabitants lived mainly by the chase), in the later settle-
ments, made after the use of metals was discovered, the inhabitants
relied chiefly on various domesticated animals for food.

Another important paper is ‘ Beitrige zur Kentniss der fossilen
Pferde und zu einer vergleichenden Odontographie der Hutthiere
im Allgemeinen, 1863; this may be regarded as laying the
foundation of that detailed comparative morphology of the teeth, in
which the homologies of the several cusps are considered, and from
which the American paleontologists have been able to draw very

lxxx PROCEEDINGS OF THE GEOLOGICAL sociuTy. [May 1896,

important conclusions as to the phylogeny of many groups of
mammals,

In a paper entitled ‘Ueber die Herkunft unserer Thierwelt :
eine zoogeographische Skizze,’ 1867, Riitimeyer gives a masterly
account of the distribution of the mammalia, showing the relations
of the fossil faunas to one another and to recent forms. Ht is a
testimony to his sagacity that the great additions to our knowledge
of this subject have confirmed most of his conclusions, and have
rendered very few untenable.

‘He was elected a Foreign Correspondent of the Geological Society
of Londen in 1877, and a Foreign Member in 1882.

Up to the time of his death Prof. Rutimeyer maintained a lively
interest in all scientific researches, and carried on his correspondence
to the last. He died at Basel on November 26th, 1895.

The Ven. Archdeacon Rosert W. Brownr, M.A., Prebendary of
St. Paul’s, was elected a Fellow of the Society in 1833, and died at
Wells on December 12th, 1895, in his 87th year.

The Rev. Lester Lester, who was elected a Fellow of the
Geological Society in 1856, died on December 26th, 1895, at his
residence, Langton Maltravers Rectory, Wareham, Dorset.

Huew Mitrer, F.R.S.E., was born on July 15th, 1850. He
received his scientific education at the Royal School of Mines, being
nominated thereto by Sir Roderick Murchison. Bearing the same
name as his distinguished father, the author of ‘ The Testimony of
the Rocks,’ ‘The Old Red Sandstone,’ etc., Mr. Hugh Miller in-
herited with the name a taste for geological pursuits. He joined
the Geological Survey in 1874, and was elected a Fellow of the Geo-
logical Society in the same year. Labouring at first among the
Carboniferous Rocks and Glacial Drifts of Northumberland, he was
subsequently transferred to the Geological Survey of Scotland, and
worked at the Old Red Sandstone around Cromarty, rendered
classic by the researches of his father. Later on he mapped
portions of the Ancient Schists, Old Red Sandstone, and Drifts of
Eastern Sutherland. Mr. Hugh Miller was taken ill at Lairg in
December last, and died at his Edinburgh residence on January 8th,
1896, in his 46th year.

He was author of the picturesquely-written book entitled ‘ Land-
scape Geology,’ and of papers on River Action and Glacial Phe-
nomena. Among the more important of these papers the following

Vol. 52. ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxxl

may be mentioned:—‘ Tynedale Escarpments: their pre-Glacial,
Glacial, and post-Glacial Features,’ 1880; ‘ River-Terracing: its
Methods and their Results, 1884; and ‘On Boulder-Glaciation,’
1884.

All who enjoyed Mr. Miller’s friendship will feel that they have
lost a kind-hearted, though keenly sensitive, friend. Strongly
imbued with a love of Nature and natural phenomena, he at the
same time kept himself in touch with the intellectual life of our
time. He leaves a widow and a son, fifteen years of age, who
is being educated at Fettes College.

JosEPpH WALTER TAYLER was elected a Fellow of the Geological
Society in 1856. He was the son of the late Admiral Tayler, R.N.,
and made several expeditions to Greenland with the object of
exploring the east coast and opening up again the old Danish
settlements said to have formerly existed along its shores, but now
completely blocked by the ice-pack, He was the discoverer of
eryolite at LEvigtok, Greenland (see Quart. Journ. Geol. Soc.
vol. xv. 1859, p. 140), and gave an account of veins of tin-ore
at Evigtok (op. cit. p. 606). He was an enthusiastic Arctic ex-
plorer, and gave to the Royal Geographical Society some interesting
observations on the Greenland glaciers, which he had carefully
studied.

Frank Jounston, F.C.S., was by profession an Assayer at the
Rio Tinto Company’s Mines. He was elected a Fellow of this
Society in 1884, and died at Tharsis, Huelva, Spain, in January
1895.

Joun Evetyn Wittiams, M.Inst.C.E., was born on January
6th, 1845, and entered the drawing office of the Mersey Dock
Estate, Liverpool, at the age of 14; there he remained for six
years. He was afterwards engaged on dock- and harbour-works at
Bristol, Hull, and Whitehaven. In 1877 he became Surveyor to
the Witham Drainage Commissioners, and was actively engaged in
the improvement of the drainage and harbours of one of the most
important tracts of the Fenland until about a year before his death,
having retired from that service in 1895. Mr. Williams was
elected a Fellow of the Geological Society of London in 1880.
Several important memoirs upon the work carried out by him have
appeared in the Minutes of Proceedings of the Institute of Civil
Engineers.

1xxxli PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

W. Srert Mitnes was elected a Fellow in 1886. He died at
Yeolmbridge, Launceston, Cornwall, in 1895.

G. W. Crine, LL.D., was elected a Fellow in 1865. He resided
at Allahabad, India, where he died.

Epwarp Joun Cuancr, F.L.S., was elected a Fellow in 1837.
He died at 14 Russell Square, W.C., in 1895.

Mr. Francis Everarp Brown, Assistant-Clerk to the Geological
Society, died suddenly from gastric ulcer on August 4th, 1895.

The Society loses in him an official whose unvarying patience,
tact, and good-humour had made him deservedly popular among
the Fellows, and whose scrupulous performance of his duties had
earned him the respect and esteem of his official superiors.

He entered the Society’s office in 1886, and had nearly completed
ten years’ service when his career of usefulness was brought to a
close.

Always delicate in health even when a child, he was unable to
indulge in those athletic sports with his schoolfellows which form
the delight of most boys; and he was thus led early in life to
take up the study of Natural History, and to make observations
on animals and flowers. This developed in him later on a taste for
scientific reading. :

He collected autographs, took great interest in all matters con-
nected with the fine arts, and had commenced to study and collect
minerals and fossils.

Mr. Brown entered Messrs. Fulcher and Robinson’s office when
only 15 years of age, and afterwards was with Mr. Sims, a stock-
broker, before he obtained his appointment at Burlington House.
Here he speedily won the confidence of the Treasurer and Secre-
taries by his willingness and constant readiness and attention;
whilst his uniform politeness to the Fellows and visitors speedily
engendered a very kind and friendly feeling towards himself, which
he retained to the end. He died at the age of 37 years.

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Vol. 52.) ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxill

By the law of periodicity, which, happily, has a constant biennial
limit, in this Society, I am about to vacate the Presidential Chair,
in which you did me the honour to place me in 1894: but before
doing so, and whilst I may yet claim the privilege of a few
remaining sand-grains in Time’s hour-glass, let me briefly draw
attention to a few topics of general interest connected with our
science, and in conclusion submit my second chapter on Crustacean
life-history in later geological times for your acceptance.

As regards Home affairs we have just cause for satisfaction with
our present financial position as a Society. Our income has not
diminished, and we have a very respectable balance in hand, more
than sufficient for our ordinary expenditure, and probably nearly
sufficient to meet such extraordinary expenses as the installation
of the electric light and the partial re-decoration of the Society’s
House.

It is satisfactory to find that the slight increase in our composition-
fee for admission to the Society (decided upon in June 1894) has
not acted as a deterrent to intending compounders, but that we
have actually had more compounders during this last year than
previously.

The completion of the 50 years’ index has been somewhat retarded
by the death of our valued and esteemed Assistant-Clerk, Mr.
Francis E. Brown, which placed, for the time being, a heavy load of
additional business responsibility on our Assistant-Secretary, who
was happily equal to the emergency, and the Society suffered no
serious inconvenience from the temporary vacancy in the staff.

The first number of ‘ Geological Literature added to the Geological
Society’s Library,’ during the half-year ended December 1894 (8vo,
pp- 58), was issued on the Ist May, 1895. On February Ist, 1896,
a similar work was issued, covering the year 1895. It extends to
158 pp. (8vo), and will certainly prove extremely valuable to all
workers in our science, particularly to Fellows in the country,
desirous of knowing what our library contains of the latest geological
interest.

The fifty-first volume of the Society’s Journal, for 1895, compares
favourably in every way with its predecessor.

Mr. E. T. Newton, F.R.S., announces the discovery of human
remains from Paleolithic gravels at Galley Hill, Kent—which, if
(in point of contemporaneous age) still involved in doubt, are yet
of extreme interest to the student of Quaternary geology. Dr.G.J.
Hinde and Mr. Howard Fox give a most interesting account of

lxxxiv PROCEEDINGS OF THE GEOLOGICAL SocleTy. [May 1896,

the discovery of Radiolaria in the chert of the Culm-beds of
Devon, Cornwall, and West Somerset; and Messrs. W. Hill and
A. J. Jukes-Browne describe the occurrence of Radiolaria in the
Chalk.

Mr. 8. 8. Buckman, in his paper on the Bajocian of the Mid-
Cotswolds, records the results of a vast amount of detailed strati-
graphical and paleontological work based upon the Ammonite and
Brachiopod faunas of this area. Dr. J. W. Gregory treats of the
Paleontology and Physical Geology of the West Indies. There are
three papers on Madagascar: (1) by the Rey. R. Baron on the
Geology of the Northern part of that island; (2) by Mr. R. Bullen
Newton on the Fossil Mollusca; and (3) by Mr. R. Lydekker on
a Sauropodous Dinosaur from the same region.

Prof. Amalizky contributes a paper on the Permian Freshwater
Lamellibranchiata from Russia and South Africa ; Mr. H. M. Bernard
one on the Systematic Position of the Trilobites ; and Miss J. Donald
treats of British Carboniferous Species of Murchisonia.

I refer to these papers in order to express the hope that they
may be taken to indicate (like the periodic variations in climatic
- conditions) a recent tendency in students of geology to turn towards
paleontology, and not to entirely ignore her in favour of her
sister petrology.

Thirty-four other papers deal with dynamical, petrological, physio-
graphical, and stratigraphical geology, in all quarters of the globe,
and demonstrate the earnest and active interest which the Fellows
of the Society take in the promotion of our science.

The Geological Survey of the United Kingdom.

In the early days of the Geological Survey my predecessors made
a point of commenting on the annual progress made by that
Institution, and remembering that some of the early fathers of the
Society had a share in the establishment of the Survey, we may
naturally feel a parental interest in its welfare.

Some years have now elapsed since any special Presidential
remarks were made on the subject; a brief reference by Prof. Judd,
a former member of the staff, appears in his address to this Society
in 1887, but the latest general account of progress was given so
long ago as 1868, by Sir Warington Smyth, who, likewise an old
member of the Survey, had in former years mapped some areas,
and had in particular traced the course of many metalliferous veins.
in his capacity of Mining Geologist.

Vol. 52.| ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxv

To note the special scientific results obtained by the Geological
Survey has, however, during the past few years, been rendered
unnecessary by the publication of the more detailed Reports of the
Director General. It is the more desirable to draw attention to
this fact, for the reports themselves, unless obtained in the form of
reprints, are apt to lie buried in the more bulky General Report
of the Science and Art Department. That Report must now be
added to our record of Geological Literature, for in the elaborate
statement of Sir Archibald Geikie we find many a new and inter-
esting fact for the first time recorded, whether it relate to England
or Wales, the Isle of Man, Scotland, or Ireland.

In parts of all these regions the Survey is actively engaged. The
mapping of the Drift deposits in the Midland and Southern counties
has been accompanied by important revisions of the more solid
geology, and the results of the work are to be seen in the issue of
sheets of the New Series of Ordnance Maps, geologically coloured,
of parts of Sussex, the Isle of Wight, Hampshire, and Devon.
The re-survey of the great coalfield of South Wales has already borne
fruit in the shape of one new map and a sheet of vertical sections.

The progress of the 4-mile-to-l-inch map of England and
Wales is of especial interest to us, as eventually it will replace our
Greenough map, which was based on the original map of William
Smith. Of the Survey map, which comprises thirteen sheets, seven
are now published, five, we are informed, are being engraved, and
one (the Isle of Man) will erelong be completed. A most important
change has this year been introduced by the Director-General, that
is, the issue of one of the sheets (that of the London Basin and
great part of the Wealden area) printed in colours. Thereby the
price has been reduced from 10s. 6d., that of the hand-coloured
issue, to 2s. 6d.—a boon indeed to the geologist, and a course well
calculated to ensure the wide circulation of the map.

Another departure made by the Director-General has been the
preparation of Stratigraphical Memoirs, and of these one volume on
the Pliocene Deposits, and five on the Jurassic Rocks have now
been issued. In them our present knowledge from all sources is
summarized, so that they may furnish stepping-stones to further
progress.

In Scotland interest of late years has been centred in the
resolute attacks made by the Survey on the problems connected
with the Scottish Highlands. Following in the wake of Murchison,
‘Nicol, and Lapworth, the officers in the field, headed by their
VOL. Lil. i]

lxxxvl PROCEEDINGS OF THE GEOLOGICAL sociuty. [May 1806,

Director-General, have grappled with the difficulties and by dint
of detailed work on the 6-inch scale have brought order into the
structure of these complicated regions. Moreover they have demon-
‘strated that in many respects the interpretation of Nicol, and the
key furnished by the hard work of Lapworth, have been most
successful in unlocking the secret of the Highlands. The maps
which picture the results of the Survey work are probably the
most elaborate that have ever been issued.

Elsewhere the Survey has been carried on among certain of the
Western Islands in Skye, Raasay, and Rona, in Canna and Islay,
and farther south in Arran.

In Ireland important revisions have been made in the older work,
especially among the Paleozoic, the Metamorphic, and the Igneous
rocks. The results may be studied in that excellent guide to the
Survey Collections in the Dublin Museum which has lately been
issued.

In noticing thus briefly the work of the Survey, I cannot avoid
remarking on the notable accession made to the staff during the
past eight years, of Teall, Lamplugh, Watts, Sollas, Gibson, and
lastly of Harker.

Among these additions it will be noticed that avery strong
Petrological element has been introduced into the Geological
Survey—needful, however, in solving the problems connected with
the ancient schists and other metamorphic rocks, and in eluci-
dating the structure of our various igneous rock-areas.

Nor has Paleontology been neglected, in testimony of which we
need only mention the papers by Mr. Peach in our own Quarterly
Journal on the Olenellus-fauna of Scotland, and the new and
strange forms of Reptilia lately described by Mr. E. T. Newton
from the Elgin Sandstone—forms which are of world-wide interest.

The acquisition of scientific facts is, however, by no means the
sole or main object of the Geological Survey. In the re-survey of
our coal-fields the practical element is foremost, while in the London
office all information that can be given is freely at the service of
those interested in the industrial applications of geology.

By the death of Huxley the Palzontographical Society loses
its President, an office which he had held since the death of Prof.
Owen, its former President, in 1892. .

But no change of Presidents can mar the useful and perennial
flow of volumes issued by this evergreen Society, which has just

‘

Fol: 52.) ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxvil

reached its Jubilee, and, like all successful and united people, it
ought to celebrate the publication of its 50th volume in some suitable
manner.

The 49 yolumes already published are the joint labours of 46
authors, about 12 of whom have, however, achieved the greater
share of the work produced. Prominent among these stand such
names as Searles V. Wood, Richard Owen, Thomas Davidson,
Edwards and Haime, F. E. Edwards, T. Rupert Jones, T. Wright,
P. M. Duncan, H. A. Nicholson, G. J. Hinde, G. F. Whidborne,
Salter, and others.

Very much of the success which has attended the Society must
be attributed to the constant care and untiring energy of its
Honorary Secretary, the Rev. Prof. T. Wiltshire, who has con-
tinually watched over the work and managed all the business
details of the Society since he took over the duties from the first
Secretary, Dr. Bowerbank, thirty years ago.

I feel that I should be wanting in gratitude to my many geo-
logical friends and supporters, did I omit, on this occasion, to thank
them most heartily for the aid that they have always afforded me
in carrying on the Geological Magazine for the past 32 years.

It is no easy task to arrange and get printed off 48 pages of
matter on one special branch of science, and issue it regularly, with
illustrations, for 380 consecutive months—but like other literary
enterprises and institutions, ‘supported by voluntary contributions,’
we might well inscribe on the cover of the Magazine as our motto
Dominus providebit; for, certainly, we have been singularly for-
tunate in our friends and supporters, amongst whom, in the past,
as in this latter-day revival, we ought especially to remember
the names of Prof. T. G. Bonney, Mr. W. H. Hudleston, and
Dr. G. J. Hinde.

Through the death of Prof. Huxley, the Royal College of Science.
was deprived of its Dean and a Professor who had been connected
with its teaching body for 41 years.

The office of Dean has since been conferred upon Prof. John W.
Judd, C.B., LL.D., F.R.S., who succeeded Prof. Sir A. C. Ramsay
in the chair of Geology in the then ‘ Royal School of Mines’ in 1877,
which was transfigured into the ‘Royal College of Science’ in
1881. Prof. Judd is a past President and Secretary of this Society,
and we trust that he may long retain his deanery, to the advance-
ment of the varlous sciences committed to his charge.

g2

Ixxxvili PROCEEDINGS OF THE GEOLOGICAL socrery. [May 1896,

Sir Joseph Prestwich, D.C.L. (Oxon.), F.R.S., now in his 84th
year, received the honour of knighthood from Her Majesty on New
Year’s Day. While we all heartily rejoice with and congratulate
him and Lady Prestwich on the honour conferred, we cannot
help feeling that the eminence to which he had long ago attained
by his scientific labours far transcends such tardy recognitiow
of his great and lasting services to geological science.

A rumour had reached me that our distinguished Foreign

Member, Prof. James Hall, of Albany, who was elected on our

Foreign list in 1848, and was Wollaston Medallist in 1858, had
retired from his office of State Geologist of New York. I find this
is not the case, the only change being that he has relinquished the
post of Director of the Albany Museum since 1893, but he still
holds the office of State Geologist. Thirteen imperial quarto
volumes on ‘the Paleontology of the State of New York’ have
been issued by Prof. James Hall, and, at the age of eighty-five
years, he is still full of life and intellectual activity and engaged on
a monograph on Fossil Sponges, the MS. of which is now nearly
completed, with 30 quarto plates already drawn and _ litho-
graphed.

We cannot but express our admiration for the marvellous energy
and determination to carry on his work to the end, displayed by
the illustrious Professor. In this country science has a more
enervating and exhausting effect on Civil Servants, and they are
deemed past work at sixty-five! Wherefore we are disposed to
envy the happy lot of our old and valued friend.

Sir J. William Dawson, C.M.G., F.R.S., whose name will
be always identified in this Society with his discoveries of air-
breathing reptiles, land-snails, and myriopods, in erect, but hollow,
trunks of trees, of Carboniferous age in the South Joggins Coal—
field (Nova Scotia), and with his papers on Hozoon and ‘ Acadian
Geology,’ etc., held the office of Principal of M‘Gill College,
Montreal, since 1855, but has now retired into private life after a
long and brilliant career. Sir William is still in full activity, and
purposes to be at the Liverpool Meeting of the British Association
this year. He received the award of the Lyell Medal in 1881.
Sir William Dawson’s Chair of Geology and Paleontology has:
been given to Prof. Frank Dawson Adams, M.A.Sc., Ph.D., F.G.S.,
a very able and promising geologist.

Another change has occurred in Canada by the votivernamt from
office of our esteemed Fellow, Dr. Alfred R. C. Selwyn, C.M.G..,.

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxix

F.R.S., from the post of Director of the Geological Survey of Canada;
he had succeeded Sir W. Logan in 1869. He joined the English ~
Survey in 1845, went out as Director of the Geological Survey
of Victoria, Australia, in 1853, and was there through all the ex-
citement of the opening up of the gold-fields of that colony. In
1869, he transferred his services to Canada, where he held office
until 1894. Counting home and colonial service, Dr. Selwyn has
been 49 years on active duty, and has served as Commissioner to
three International Exhibitions. He received the Murchison
Medal in 1876.

Dr. Selwyn has been succeeded as Director by Dr. George M.
Dawson, O.M.G., F.R.S., F.G.S., eldest son of Sir William Dawson,
who was on the North American Boundary Commission in 1873,
and joined the Geological Survey in 1875. He has already
served on several Royal Commissions, the last being that on the
Behring Sea Fisheries; has made numerous communications to this
Society, and was the recipient of the Bigsby Medal in 1891.

Dr. G. M. Dawson is one of the few individuals (of whom Sir
Charles Lyell in 1864 was another instance) who may have read his
own obituary, for his death was announced on November 12th,
1895, but was speedily contradicted by Sir Charles Tupper, High
Commissioner for Canada, who cabled out at once and found
that an error in the spelling of the name had changed Lawson into
Dawson.

In our Indian Empire Dr. William King, B.A., who joined
the Geological Survey in March 1857, and succeeded Mr. Med-
licott as Director in 1887, retired from office on July 16th,
1894. During the 37 years of Dr. King’s connexion with the
Survey he published thirty-five papers, dealing mostly with the
geology of the southern and central parts of India. He was suc-
ceeded on July 17th, 1894, by Mr. Carl L. Griesbach, C.I.E., F.G.S.,
who joined the Survey in Sept. 1878. Mr. Griesbach is the author
of 26 papers on geology, from 1868 to 1893, He was employed
on the Afghan Boundary Commission, from November 1884 to
October 1886, and as Geologist to His Highness the Amir of
Kabul, from January 1888 till July 1889. He has contributed
some important work on the geology of the Himalayas, and received
the gold medal from the Emperor of Austria in recognition of
his services rendered in connexion with the scientific expedition
in 1892 to the central regions of the Himalayas.

Another of our Fellows, Prof. John Milne, F.R.S., after spending

men as PROCEEDINGS OF THE GEOLOGICAL socrery. [May 1896,

20 years at the Imperial College of Engineering, Tokio, Japan, and
devoting his time and income to the investigation of earthquake-
phenomena in that centre of remarkable disturbance, has now
returned home from Japan and has established a station for seis-
mological observations in the Isle of Wight.

Some of his latest researches on the propagation of earthquakes
to great distances have led him to most interesting conclusions.

In the case of the Argentine earthquake of 1894 Milne was
successful in showing that a large disturbance might be recorded
at the antipodes of its origin. The pronounced movements of an
earthquake travel over paths around an epicentre at a rate of
2 or 3 kilometres per second, and they are transmitted, at the
same rate, to places distant more than a quarter of the earth’s
circumference. Preceding these pronounced movements which
apparently radiate as quasi-elastic gravitational waves, minute
tremors are observable, which, in travelling from Japan to Kurope,
apparently outrun the main disturbance by half-an-hour. The
velocities at which these are propagated have been estimated as
varying between 8 and 20 kilometres per second.

Assuming these determinations to be approximately correct, it

is difficult to escape the conclusion that the motion, instead of
having been transmitted through the crust of the earth, has been
transmitted through its interior. Prof. Milne writes:—‘ When a
number of properly-equipped observing-stations have been esta-
blished around our globe, it seems likely that we shall be in a
position to state definitely the velocity with which motion travels
along paths at varying depths in the earth’s interior. From the
little already accomplished, it appears that, if our globe is capable
of transmitting motion two or three times more quickly than steel,
it has an effective rigidity very much higher than has hitherto been
supposed.’ » :
' Thanks to these researches and experiments, carried out in
codperation with the late HE. von Rebeur-Paschwitz and other
observers in Europe, we may hope, possibly within a few years, to
have a definite solution of what has heretofore been to geologists
truly a terra incognita—the nature of the structure of the interior
of the earth. .

On his retirement in 1895, Prof. Milne received from the Emperor
the well-merited decoration of the Rising Sun, in recognition of the
valuable scientific work performed by him during his long a

in Japan.

eh eee
mane ot Vani aen

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. XCl

LIFE-HISTORY OF THE CRUSTACEA IN LATER Patmozorc
AnD IN Nzozoric Timzs.

In my Address, in February last year, I endeavoured to set
before you as briefly as possible, an epitome of the more interesting
points in the earlier chapters of the life-history of the Crustacea—
a Class so ancient as to entitle it to take precedence over the whole
of the Vertebrata, and probably over half the Invertebrata also, in
the geological record.

From Lower Cambrian times to Carboniferous we showed that
the Crustacea were mainly represented by the great and numerous
order of the Trilobites, while bivalved Ostracods, huge Pod-shrimps
(Phyllocarida) and giant Merostomata, such as Hurypterus and
Pterygotus, with a few small King-crabs, fill up the picture of
marine crustacean life.

To whatever part of the world we direct our gaze over the Paleo-'
zoic seas, the same group of organisms is more or less abundantly
represented ;—indeed it may be said that, until we reach the Upper
Silurian, the Trilobites almost entirely occupy the primeval waters’
to the exclusion of other crustacean life. But from this stage up--
wards the Trilobites are more restricted, while the large Pod-shrimps,
Ceratiocaris, appear in numbers, together with the gigantic Ptery-
gotus, the latter attaining its maximum in the Old Red of Scotland.

Some 8 or 9 genera of Trilobites still continue on in the Devo-
nian and the Carboniferous Limestone, in the latter formation
reduced to about four genera, after which they disappear entirely.

Whether the Trilobites continued to live on in some of those
marine areas which probably existed adjacent to the larger fresh-
water and estuarine ones, amidst which the great subaerial growths’
of the Coal-period were being accumulated, we do not certainly
know, but in the succeeding Permian epoch they have left no
evidence behind.

As we scan the record of these old Carboniferous rocks, so rich in
organic remains, we seem to stand on some lofty beacon-hill, whence
we can cast our glance upwards and downwards along the stream
of time. Beneath our feet lie buried the last representatives of
those aboriginal races now quite extinct, the Trilobita and the
EKurypterida, whose ancient hosts peopled the seas of Devonian and
Silurian ages and some of whose predecessors reached far away
to the Lower Cambrian epoch. Beside them lie the earliest repre-
sentatives known of our modern Decapoda, Stomatopoda, and Isopoda,
then but a few and feeble folk, but now the dominant races of the

xeli PROCEEDINGS OF THE GEOLOGICAL sociery. [May 1896,

Crustacean class. Is this then the great barrier-reef between the
Paleozoic and Neozoic life-periods? Do we indeed find here the
beginning of all modern forms of Crustacea and the ending of all
ancient ones ?—By no means; nor is there any period in the whole
geological record at which a hard-and-fast line can be drawn
dividing the earlier from the later members of any group.

_ Certain tribes, such as the Entomostraca, are represented through-
out. Others, like the Amphipoda, may perhaps extend into Silurian
times,—whilst Isopods and Decapods are probably represented as
far back as in Devonian strata.

The Crustacea, in fact, bear testimony to the same general bio-
logical law which holds good in so many other classes of organisms,
namely, that before one order dies out and disappears, other and
successive groups have already made their appearance: the one
overlapping the other in time.

There are, indeed, no sharp divisions in living Nature, ae
rather a subtle interblending of groups which, like the prismatic
colours in the rainbow, shade off imperceptibly the one into the
other.

Matacostraca.—Throughout the sub-class Manacostraca, to which
so large a proportion of the Mesozoic, Cainozoic, and Recent forms of ~
Crustacea belong, the number of segments present is generally very
persistent: for the three divisions of the body (head 6, thorax 8, and
abdomen 7=21). They fall naturally into two groups, (1) the Epr10-
PHTHALMA, in which the eyes are sessile, and (2) the PopoPHTHALMA,
in which they are pedunculated.

Ampuipopa.—In the Amphipoda belonging to the first of these
divisions, with sessile eyes, the body is pretty constantly and
regularly developed, the small cephalothoracic head-shield only
covers its own series of seven paired appendages, while the thorax
and abdomen have usually each their proper and normal series of
seven free somites, with a corresponding pair of limbs attached to
each segment. 7

Most of the members of this order are of small size, with a
laterally compressed body ; but their numbers are almost incredible,
and they are most widely distributed not only in freshwater lakes
and rivers, springs and subterranean watercourses, but they are
found living along the shores of almost every land in the open air!
and also between high and low tides.

1 Some species of Orchestia are known (as O. tahitiensis, O. telluris, O. sylvi-
cola) which live far removed from the sea and at elevations of 1000 feet.

Vol. 52.| ANNIVERSARY ADDRESS OF THE PRESIDENT. Xciil

- In 1870 I described what I believe to be a portion of a fossil
Amphipod from the Lower Ludlow Rocks of Leintwardine, Shrop-
shire, under the name of Necrogammarus Salweyi; it is not quite
certain whether Gampsonyx fimbriatus, Jordan, from the Coal-
Measures of Rhenish Prussia, is correctly assigned to this division,
but I am inclined to retain it here, however, as its most natural
position. Mr. Spence Bate has named and described a species of
Amphipod as Prosoponiscus problematicus, from the Magnesian
Limestone of Durham.

Other fossil forms occur in the Tertiary rocks and are mostly
referable to existing genera such as Gammarus, G. aningensis,
from the Miocene of iningen; and Palwogammarus sambiensis, from
the Baltic amber deposits, etc. ,

Isopopa.—This division of the Malacostraca is marked by the
persistence of the seven pairs of ambulatory thoracic limbs, which
never bear the gills attached to their bases as in the Amphipoda,
but the appendages: of the abdomen take on this function, being
specially modified into leaf-lke branchial organs and do not take
part in locomotion, save in the swimming forms. The members
of the group are for the most part of small size. Many of the living
Isopods are attached to fishes and crustacea, and one parasitic fossil
form is known (Bopyrus).

Numerically, the order is large and very widely distributed geo-
graphically, consisting of walking, running, and swimming forms;
and lastly of sedentary parasitic forms—of these it is the female only
which remains fixed, the male being often peripatetic in his habits,
passing from female to female. Many Isopods—e. g. the Oniscide
—live habitually on land, breathing air, which it is necessary should
be fairly moist; hence they usually frequent damp situations,
under decaying wood and leaves, and beneath stones. The Sphero-
mide frequent rocky shores, and run and swim with considerable
agility. Many forms of Isopoda are strictly marine, some occurring
at great depths (over 2000 fathoms). Some few Isopods have been
met with of larger size than the average members of the group.
‘One, dredged by Prof. Alexander Agassiz, during the cruises of the
‘ Blake,’ from a depth of 955 fathoms on the north-east of the bank
of Yucatan, and north of the Tortugas, named Bathynomus giganteus
by Alph. Milne-Edwards, measures 9 inches in length by 4 in
breadth, and far exceeds any other living species in size. Not-
withstanding the vast depth from which Bathynomus was obtained,
the eyes are well developed, but instead of being placed upon the
upper surface of the head as in all known wandering Cymothoide,

X¢clv PROCEEDINGS OF THE GEOLOGICAL sociETY. [May 1896,

they are placed below the frontal border of the head, at the base of
the antenne.

I formerly entertained a very strong conviction that it would be
possible to show the derivation of the Isopoda by direct descent:
from the Trilobita; but the former have so very constant and
definite a number of 21 body-segments—as indeed is the case in the
Malacostraca generally—(namely, 7 somites in the head, 7 in the
thorax, and 7 in the abdomen), whereas in the Trilobita (as is the
case with the Entomostraca generally) the number varies greatly,
from 4 or 5 up to 28 somites in the body, that I feel I must recant
and give up this heresy at once, lest I should be excommunicated.
by some later Carcinologist, and my effigy and papers burnt, if not
my person. .

It is probable that the Isopoda date back to the Devonian, for I
have, in 1870, described, under the name of Prearcturus gigas, a
form which appears to be a portion of a huge Isopod from the Old
Red of Rowlestone, Herefordshire.

Portions of similar large Arthropods, which have been named
Arthropleura ferox, by Salter, and A. armata, by Jordan, have been
obtained from the Coal Measures of Manchester, of Fifeshire, of
Radstock, Somerset, and from Saarbriicken, Rhenish Prussia, so that
we may justly hope soon to obtain a fuller knowledge of the true
characters of this remarkable animal.

The anomalous form, known as Bostrichopus antiquus (Goldfuss).
from the Devonian of Nassau, may perhaps be placed here, as:
possibly related to the Munnopside.

Several species of Palewocaris (P. scoticus, P. Burnetiu, and P. ty-
jus) have been described from the Coal Measures of Manchester, of
Scotland, of Bohemia, and of Grundy County, Illinois, U.S.A. ; from
this last-named locality another genus, Acanthotelson Stimpsona,
closely resembling Palwocaris, has also been obtained by Messrs.
Meek and Worthen. These larva-like forms were relegated, by the
late Prof. J. D. Dana, to a group holding an intermediate position
between the typical Isopoda and the Amphipoda, for which he pro-
posed the name ‘ Anisopoda.’ |

Isopodites triasicus, Picard, from the Muschelkalk of Thiele
is somewhat doubtful. An undoubted Spheroma-like Isopod, from
the Great Oolite of Northampton, has been described by me under
the name of Cyclospheroma trilobatum, in 1890.

The Lithographic Stone of Solenhofen, Bavaria, has yielded two
genera of Isopodous Crustacea, described in 1839 by Count Minster,

Vol. 52.] _ ANNIVERSARY ADDRESS OF THE PRESIDENT. XCV

and named Urda and Reckur. A third Solenhofen form has been.
more lately described by von Ammon as Aigites Kunthi.

The well-known and abundant <Archewoniscus Brodiei, of West-.
wood, described in 1845, from the Purbeck of the Vale of Wardour,
Wiltshire, closely resembles existing members of the family Oniscide,
to which it probably belongs. Mr. Westwood added another species,
Archeoniscus Edwardsi, from the Lower Purbeck of Durdlestone
Bay, Dorset, in 1854.

We owe to Prof. Bell the discovery of the parasitic Isopod,
Bopyrus, beneath the carapace of Palcococystes, from the Cambridge
Greensand, in 1862. ‘The females of similar forms infest the cara-
paces of the common Prawn around our coasts at the present day.

Palega Maccoyi, Carter, is from the Upper Greensand of Cam-
bridge, and Palega Carteri, H. Woodw., from the Grey Chalk of
Dover. Cymatoga Jazikowi, Kichwald, from the Chalk of the
Volga, completes the series of Cretaceous Isopods. Nearly allied to
Palega Cartert is P. scrobiculata from the Lower Oligocene of
Haring, Tyrol.

The Eocene of the Paris Basin and the Isle of Wight has yielded
four species of the genus Hospheroma’; Spheroma Catulloi is
from the Eocene of Italy ; and one occurs in the Miocene of Bonn.
Sismonda, in 1846, recorded and figured a Spheroma (= Palcega)
Gastaldi from the Miocene of Turin; and Oswald Heer a species
of Woodlouse (Armadillo molassicus) from the Miocene freshwater
strata of Giningen. Five others (Cymodocea sarmatica, Andr. ;
Spheroma exors, Kichw.; Sph. faveolatum, Costa; Pulega anconi-
tana, Andr.; Archeospheroma Friciz) are all Newer Tertiary forms.

A species of Oniscus,* a Trichoniscus, and three species of Por-
cellio are all described from the Amber-deposits of Tertiary age on
the Baltic coast ; and a fossil Spheroma (S. Burkartic) has been
described from Mexico by M. Barcena.

PuyLbocaripA and Comacra.—Standing on the border-line be-
tween the Malacostraca and Entomostraca are the PHyLtocarrpa,
represented at the present day by the genus Nebalia, which affords
a connecting-link between the Phyllopoda and the Malacostraca
(see my previous address, Feb. 15th, 1895, pp. lxxxiii & lxxxiv).

In the earlier of these ancient Silurian ‘ Pod-shrimps,’ such as

1 Namely, Hospheroma Smithii, E. fluviatile, H. W., LE. Brongniarti, Edw.,
E. obtuswn, H. von Meyer.

? Namely, Oniscus convexus, Koch, Tertiary amber-deposits, Baltic. Tricho-
niscus asper, Menge, loc. cit. Porcellio notatus, Koch, P. granulatus, Menge,
P. cyclophorus, Menge, loc. cit.

X¢eV1 PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1896

Ceratiocaris papilio, C. stygia, and C. Halliana, the carapace
is large and is composed, as in the living Nebalia, of a re-
duplication or fold of the dorsal integument of the head-segments,
which stretches backwards and forms a separate cover or shield,
not only to the cephalic and thoracic segments but even to some of
the abdominal ones as well.

In some of the later forms, more particularly in species like
Ceratiocaris scorpioides and C. elongatus, described and figured by
Mr. B. N. Peach, F.R.S., from the Lower Carboniferous rocks of
Eskdale, the carapace is quite small and only about one-fourth the
length of the body, leaving about 10 segments of the slender
thorax and abdomen exposed to view.

This is precisely what one sees in the living forms of the genera
Cuma, Bodortia, Diastyls, etc., and one is led to the conclusion
that we have here, in all probability, a passage upward from the
more ancient Phyllocarid type (in which a larger expansion of the
head-shield and a larger number of post-cephalic segments exist),
to the more modern Cumacea (in which only a small dorsal shield is
developed, formed partly by connecting some of the anterior thoracic
terga with those of the head), and thus gradually leading up to the
Decapoda (in which all the thoracic terga unite with the head to
form a true cephalothoracic carapace as in Astacus and Homarus).

PopoputHarmMa.—1l. The Sromaropopa—represented at the pre-
sent day by Squilla and five other genera—are of especial interest
to us as, they offer so many important points of difference in their
structure from other adult crustacea. It is in this sub-order that
the typical number of 21 segments can always be distinguished.
The carapace is quite small, and only covers a part of the cephalo-
thorax, while the gills are carried exposed in tufts attached to the
abdominal swimming-feet. The second maxillipeds—usually small
mouth-organs—are developed in Squilla into a pair of large and
powerful raptorial claws, taking the place of the chelate limbs of
the common lobster and crab.

From their extensive distribution over the seas of the globe,
their past life-history and high antiquity, the Stomatopoda justly
challenge the attention of the paleontologist.

They make their appearance as far back in geological time as
the Coal Measures ‘—one species, Necroscilla Wilsoni (H. Woodw.),

1 There is a doubtful form (Amphipeltis paradoxus), Salter, occurring
in the Devonian of St. John, New Brunswick, which may belong to the
Stomatopoda.

Vol. 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. X¢Vll

having been met with in the Middle Coal Measuresof Cossall, near
Ilkeston, Derbyshire, by Mr. Edward Wilson, F.G.S., in 1876.

It is highly probable that Diplostylus Dawsont, Salter (1863),
from the Coal Measures of Nova Scotia, was related to Necroscilla
Wilsonz, but it does not appear to have possessed appendages to
the penultimate body-segment as seen in the latter genus.

The remarkable genus Pygocephalus, represented by P. Cooperi and
P. Husleyi, from the Coal Measures of Shropshire, Lanarkshire, ete.
offers characters common to the Stomatopoda, the Decapoda, and
the Schizopoda, showing clearly the narrowness and artificiality of
our classifications, which must ever need to be enlarged, in order
to embrace all the varied forms which now live or have existed in
past times.

Small, but well-preserved, specimens of Crustacea, belonging to
the genus Squilla, described by Count Minster, in 1839, as Sculda
pennata, are known from the Lithographic Stone of Solenhofen in
Bavaria. They differ little (save in the spinose ornamentation on
the abdominal and caudal segments and appendages) from the
existing species of Squlla.

The Cretaceous deposits of Hakel, in the Lebanon, have yielded
to the patient labours of the late Rey. Professor E. R. Lewis,
F.G.S., of the Syrian Protestant College, Beirit, a well-preserved
fossil Squilla which I described and named, in 1879, as S. Lewis7,
after that enthusiastic geologist. A Squlla from the same locality
(in 1886) has been named Sculda syriaca by Dames. Schliiter has
named two species, Pseudosculda levis and Squilla cretacea, from
the Chalk of Westphalia.

Another fossil example met with was obtained from the London
Clay of Highgate by the late Mr. N. T. Wetherell, F.G.S., and was
described and figured by me, in 1879, as Squilla Wetherelli. Lovisato
(1894) has recorded a Squilla mzocenica from the Miocene of
Sardinia. These Secondary and Tertiary Squwille all closely
approximate to existing forms of Stomatopoda, but the ancient
Carboniferous representatives of this sub-order suggest a more
generalized type of structure than those of later times.

Notwithstanding their wide distribution in time and space, the
Squillide are of rare occurrence—both recent and fossil. Two causes
may probably assist in explaining this: first, the thinness of the
test, which would render it less likely to be preserved ; and secondly,
the fact that all the species are fossorial in their habits, forming

XVI PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

a very deep, nearly vertical, cylindrical burrow: this goes down
for several feet into the sand, which is hardened by the pressure
of the dorsal surface of the animal’s body. ‘They thus, too, often
escape capture by collectors in the living state, and are too delicate
to preserve well when fossil.

2. The Scu1zopopa,—represented at the present day by Mysis,
and numerous other allied genera,—occupy the most primitive
position in the order Podophthalma, and still retain unchanged
the original characters which distinguished the progenitors of the
group in earlier times.

This is further emphasized by the fact that many Decapod Crus-
tacea, in their more-advanced larval stages, pass through a ‘ Mysis-
stage’ before reaching the adult condition.

Eight pairs of similarly-formed thoracic limbs are predert (namely,
three pairs of maxillipeds, and five pairs of posterior appendages),
each being furnished with a well-developed exopodite and endo-
podite, and frequently bearing freely-projecting external gills, not
covered by the cephalothoracic shield.

Considering the greater simplicity of the forms in this division,
it seems highly probable that some of the earliest Macruran Crus-
tacea, such, for instance, as the Paleocrangon socialis of Salter,
from the Coal Measures of Fifeshire, may have belonged to the
Schizopoda, but very few of these are sufficiently well-preserved to
render exact determination possible.

Such forms as Udorella Agassizi, Oppel, from the Lithographic
Slate of Kelheim, Bavaria, in which the cephalothoracic shield is short,
and the legs uniform and provided with endopodite and exopodite, °
may, I think, with almost absolute certainty be referred to this
division.

Macroura.—the earliest example known of fie modern division
of Crustacea was obtained by Prof. R. P. Whitfield, in 1880, from
the Erie Shales (Upper Devonian), Le Roy, Lake Co., Ohio, U.S.A.,
and named by him Paleopalemon Newberryi, which in its general
characters closely resembles the modern Crangonidea, the Shrimps
and Prawns.

To this division must also be referred the Palewocrangon esk-
dalensis of Peach (1880), from the Lower Carboniferous rocks of
Eskdale, Scotland.

Eight species of Anthrapalemon from the Coal Measures of
Scotland and England; one from Illinois, U.S.A.; and one from

Vol. 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. XC1xX

Nova Scotia, illustrate the abundance of these small crustacea in
the Carboniferous period. They have many points in common, but
probably deserve more than specific differentiation.

With the exception of Anthrapalemon Parkii, A. Traquairu, and
A. Etheridge, which measure from 3 to 5 inches, the other species
do not exceed 1 to 2 inches in length.

The carapace and body-segments were evidently and usually
broadly expanded, as in the Eryonide; the large scale at the base
of the outer antenne suggests the Peneide; the strong basal
joints of the inner pair of antennez with bifid flagella, and the outer -
pair with single ones, are like many of the modern Caridea and
Astacidea ; the caudal appendages forcibly recall the rhipidina of
the living Galatheide, in which, as in some ancient forms, there
are two additional broad lamelle to the tail-fan, developed one on
either side of the telson. [This fact, as Peach correctly observes,
strongly favours the view that the telson should not be treated as
a mere median appendage, but as a true 21st body-segment. |

In the spinose ornamentation of the somites and caudal plates ;
in the broadening out of the segments of the abdomen and the short
rounded form of the cephalothoracic shield (especially in Anthra-
palemon Parkiv) one is reminded of the genus Squilla, but most
probably this is only an analogy and nothing more. There is some
evidence, though not quite satisfactory, that the branchiz may have
been partly exposed as in Mysis, but we need further light on this
point.

Enough has been said, however, to show that the small Carboni-
ferous Crustacea are much more generalized than their modern
descendants, and probably stood in the position of great an-
cestors to most of the living Macrura and even to the Brachyura
also.

The Caridea, embracing all the shrimps and prawns, and possibly
also some of those ancient Carboniferous species of Anthrapale-
monide already referred to, are divisible into the Monocarpinea,
the Polycarpinea, and the Crangonidea.

MonocarPingeA.—In this section the fifth joint of the wrist of the
second pair of thoracic limbs is not subdivided, and the chele of this
pair are larger than those of the first pair.

The living representatives are divided into eleven families, the
best known perhaps of which is that of the Palemonide, embracing
the true Prawns. In these the first and second pairs of thoracic

c PROCEEDINGS OF THE GEOLOGICAL sociETY. [May 1896,

legs are chelate, the second being the longest pair; the carapace is.
-even and rounded, with two points, the one above, the other
beneath the peduncle of the external antenne; the rostrum is of
great length, curved upwards, and armed with 7 or 8 teeth above
and 4 or 5 beneath ; the inner antenne have three filaments, two of
which are long; the outer antenne have filaments of very great
length, and a long and pointed scale near the base. The oldest of
this type known is the ger raiblana from the Trias of Raibl,
Austria. Two species of Zger, namely, 4. Marderi and 4. Brodie,
have been described by me from the Lower Lias of Lyme and of
Warwickshire; five forms of the same genus have been figured by
Miinster and Oppel from Solenhofen, remarkable for the length of
the rostrum and of their last pair of spinose pediform maxillipeds.
The genera Udora, Hefriga, and Elder, from the Lithographic stone,
probably all belong here.

Another Prawn, Oplophorus van-der-Marcki, Schliiter, is from
the Chalk of Westphalia; two species of the genus Homelys (a
freshwater Prawn) are from the Miocene of Giningen ; Micropsalis
papyracea, H. vy. Meyer, from the Tertiary Paper-coal of Rott, near
Bonn, and Palemon exul, Fritsch, from the Tertiary of Bohemia,
complete this tribe.

PotycaRPINEA.—This section embraces the families Nikide,
Alpheide, Hippolytide, and Pandalide. All the members of
this group are distinguished by one common character: it is, that
the second pair of slender thoracic legs have the carpus, or fifth
joint, multiarticulate—that is, subdivided into a greater or less
number of minor joints, like the flagellum of the lobster’s antenna.

It is interesting to record that this remarkable and multiversatile
hand had already been in use, no doubt prior to the Upper Jurassic
period, for the genus Blaculla had just such slender limbs of this
pattern, one fourth longer than its entire body. Three species have
been noticed by Oppel from the Lithographic Stone of Solenhofen in
_ Bavaria; while 27 genera of world-wide distribution still illustrate
the convenience of this form of limb, which may serve to assist this
small Shrimp to extract, from spiral shells and slender worm-tubes,
food of a nutritious and appetizing kind.

CraneontpEA.—In Crangon the rostrum is absent or rudimentary ;
the inner antenne have a dilated base terminating in two filaments ;
the external antenne are nearly on the same line with the inner
ones, and have a large scale at the base; the first pair of thoracic
legs is subchelate; and the finger is inflected to meet a small

Mol. 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. cl

rudimentary thumb. The hinder margin of the carapace is over-
lapped at the sides by the first segment of the abdomen.

It seems probable that Udorella Agassizi, from the Lithographic
Stone of Solenhofen, belongs here: the feet are monodactylous, but
the outer antennz each have two flagella, and the thoracic feet
carry endopodites externally, which may be gills as in Mysvs.
Pseudocrangon tenuicaudus, from the Chalk of Westphalia, should,
I think, be placed here.

The position of Paleocrangon eskdalensis, from the Lower Carboni-
ferous of Scotland, is very doubtful.

Mesocrangon atra is from the Gault of Folkestone, and Pseudo-
crangon from the Chalk of the Lebanon.

The PrnzrpeEa, typified by the genus Peneus, are a group
abundantly represented in the Secondary rocks. The oldest form
is probably the Penaeus lassicus, Oppel, from the Lower Lias,
Schambelen, Switzerland, and next comes P. Sharpii, H. Woodw.,
from the Upper Lias of Northampton. There are, moreover, five
well-preserved species, figured and described by Oppel from the
Lithographic Stone of Solenhofen. Acanthochirus 3 species, Bylgia
3 species, Drobna 2 species, and Dusa ? 3 species, are also considered
to belong to the Penxide. Penewus septemspinatus, Dames, and
P. libanensis, Brocchi, are from the Cretaceous of the Lebanon.

Peneus and 20 other genera allied to it are living at the present
day very widely distributed geographically. The New South Wales
species, P. esculentus, attains a length of 9 inches, and is largely used
for food. The genus is of especial interest, not only as occurring
fossil, or as being edible, but from the fact that, so far as we at
present know, it is the only Macrurous Decapod in which the
young passes from the egg as a simple Nauplius-larva, similar to
that of a young Copepod, Cirripede, or Phyllopod-larva just hatched
from the egg, and advances through a series of moults to a Mysis-
formed zoea before attaining the adult stage.

AsractpEa.—Of the section Astacidea, the Eryontide occupy the
first family, but they are peculiar and vary considerably from the
ordinary type.

Eryontipz.—The genus Eryon was first made known by Des-
marest in 1822, and was applied by him to a group of Macrurous
Crustacea with a broad and flat carapace, strongly notched or indented
around the anterior border, but with straight sides ; the antennules
are small, and bear multiarticulate flagella : there ia a narrow scale
near the base of each outer antenna, the flagellum being of moderate

yOL, LII, h

Cli PROCEEDINGS OF THE GEOLOGICAL socieTY.. [May 1896,

length and stoutness. The abdominal segments are short and flat,
but narrower than the carapace, and terminate in a rather pointed
telson and 4 tail-lamine. The first pair of thoracic legs are nearly
as long as the body : all the limbs have chelate extremities, save the
last pair, the extremities of which are simple.

It is not improbable that the earliest members of this ancient
family (which attained its majority in the Upper Jurassic period)
may be traced back as far as the Lower Carboniferous of Eskdale,
Scotland; and they may be identified with such species as Anthra-
palemon Macconochu, A. Woodwardu, and some others (see Quart.
Journ. Geol. Soc. 1879, vol. xxxv. pl. xxi. p. 464) described by
R. Etheridge, Jun. Another early form is the Hryon raiblanus,
Bronn, sp., from the Trias of Raibl, Bohemia; followed by the
Eryon (Tropifer) levis of Gould from the Rhetic Bone-bed of
Aust.

In the Lias formation there are ten described species, namely :—

Eryon Calvadosii, Moriére, U. Lias, Caine, Calvados,
», Hartmanni, Meyer, U. Iias, Wiirtemberg.
» Ldwardsi, Moriére, U. Lias, Calvados.
», Moorei, H. Woodw., U. Lias, Ilminster.
» Lscheri, Oppel, L. Lias, Baden.
» antiguus, Brodp., L. Lias, Lyme Regis.
» barrovensis, M‘Coy, L. Lias, Barrow-on-Soar.
» wilmcotensis, H. Woodw., L. Lias, Wilmcote,
» Brodiei, H. Woodw., L. Lias, Lyme Regis.
» erassichelis, H. Woodw., L. Lias, Lyme Regis,

One species occurs in the Great Oolite (Stonesfield Slate), namely,
the Eryon Stoddartt of H. Woodward, while the Eryon Perroni of
Etallon occurs in the Oxford Clay of Calmoutiers, Haute Sadéne,
France.

Ten species of Eryon have been described from the Lithographic
Stone of Solenhofen (probably near the horizon of the Kimmeridge
Clay of England), namely :—

Eryon propinquus, Schloth. Eryon bilobatus, Miinst.

» spinimanus, Germar. » longipes, Fraas.

» orbiculatus, Miinst. » NSchuberti, Meyer.

», elongatus, Munst. », Ledtenbacheri, Miinst.
» arctiformis, Schloth. » Oppeli, H. Woodw..

I have described one Lower Cretaceous species under the name
of Eryon neocomiensis, from the Neocomian of Silesia.

Lastly, we are indebted to the Naturalists of the Challenger
Expedition for a knowledge of several living representatives of

oA

Vol. 52.| “ANNIVERSARY ADDRESS OF THE PRESIDENT. cil

the family Eryontide, referred to the genera Polycheles, Pentacheles,
Stereomastis, and Wiillemoesia, from the Mediterranean, the Atlantic,
and the Pacific, obtained from depths varying between 220 and 1900
fathoms. The recent species bear a very close resemblance to their
Liassic and Oolitic ancestors, and they offer a striking illustration
of the vast length of time over which a family may extend with
very little alteration as regards general form.

What is the reason for the remarkable fact that so many old-
world genera, belonging to such varied forms as Nautilus, Pleuro-
tomaria, Pholadomya, Arca, Calveria, Pentacrinus, Polycheles, etc.,
dating from the Mesozoic period rather than the modern one,
should still be found living in the deeper waters of our present
oceans? Are we justified in concluding that they have so survived
because those areas have remained undisturbed since the close of
the Permian epoch? Or have they been compelled to occupy the
deeper waters by other and stronger forms of marine life?

The ScynraripEa might, at first sight, appear to offer an analogy,
in their broadly-expanded and fiattened-out cephalothorax and
abdomen, to the genus Hryon, but they are in reality very widely
separated from that family (which are Astacidea), the broad and
serrated front of the carapace in Scyllarus, Thenus, and Ibacus
being largely due to the very singular modification of the great,
pair of outer antenne, the joints of which are flattened out into
enormously broad and spinous fan-shaped scales, the eyes being
usually inserted in deep hollows near their bases at the outer
anterior angles of the head, but in Jbacus they are set nearer the
front centre.

These singular forms are recorded as far back as the Gault, two
species having been noticed by me from that formation and named
Scyllaridia Gardneri and Scyllaridia punctata (Geol. Mag. 1873).
Ibacus precursor of Dames is from the Chalk Rock of the Lebanon,
Other species from the London Clay have been figured and described
as Scyllaridia Koenigu, S. Bellu, and Thenops scyllariformis, all from
the Isle of Sheppey.

It is interesting to record that the late Prof. von Seebach
discovered and described a larval Palinurid from the Lithographic
stone of Solenhofen, well known—among living Crustacea—as ‘ the
Glass-crab,’ Phyllosoma’; some of these Phyllosome have been
proved to be the larval stages of the Scyllaride.

1 Minster, ‘ Beitrage zur Petrefaktenkunde,’ Heft i. p. 84, pl. viii. figs, 3, 4.
4to. 1839.

h2

Civ PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

Prof. Dames has described and figured two supposed larval
forms of Crustacea from the Cretaceous of the Lebanon, under the
names of Pseuderichthus cretaceus and Protozoéa Hilgendorfi, which,
in the long produced fore-and-aft spines on the carapace, call to
mind the larve of Hippa, Porcellana, and of some other living
Decapoda.

Parinvrip%.—In Palinurus the carapace is less expanded and is
longitudinally subcylindrical, with the orbits partially excavated and
the eyes protected by strong spines; the external antennz are very
thick and long, their basal joints strong and spinous. The internal
antenne are principally composed of three long joints, with twe small
flagella at their extremities. All the feet are monodactylous, The
tail is very broad, and the outer lamella is not jointed.

Palinurina longipes, Minster, is found in the three divisions of
the Lias of England, and in the Lithographic stone of Solenhofen,
Bavaria, and other localities.

Palinurus (Glyphea) Semanni, Oppel, sp., and P. Woodwardi,
Fritsch, come, the former from Solenhofen, and the latter from the
Chalk of Bohemia. P. nanodactylus, Schl., sp., is from the Chalk
of Sendenhorst, Westphalia.

Cancrinus claviger and Cancrinus latipes make us acquainted
with a very remarkable Palinurid from Solenhofen, in which the
outer antenne are developed into large multiarticulate club-shaped
organs.

Here is also placed a singular crustacean with simple monodactyle
thoracic limbs, from the Lower Lias of Barrow-on-Soar, Leicester-
shire, named by me Preatya scabrosa.

Archeocarabus Bowerbankii, M‘Coy, carries the Palinuride on into
the Eocene Tertiary strata, and the Palinurus vulgaris (or common
‘Spiny’ Crawfish) is living around the rocky parts of our own
coasts and those of France and the Mediterranean, and elsewhere,
abundantly to-day.

There are several fossil forms of long-armed monodactylous crus-
taceans which have been placed here, presumably for convenience ;
beginning with Scapheus ancylochelis, H. Woodw., from the Lower
Lias of Lyme Regis (Quart. Journ. Geol. Soc. vol. xix. 1863, pl. xv.) ;
Mecochirus Pearcei, M‘Coy, and M. socials, Meyer, sp., from the
Oxford Clay of Christian Malford, Wiltshire ; Mecochirus Peyton,
H. Woodw., from the Kimmeridge Clay, ‘Sub-Wealden Boring,’
Sussex ; and represented by six long-armed species from the Litho-
graphic Stone of Solenhofen Bavaria. These singular forms were

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT, CY)

probably all of them burrowing species, using their long arms to
assist them in the procers.

_ Girpxazipz.—This family is represented by the genus Pemphix,
and appears first in the Muschelkalk of Crailsheim, Germany.
It approaches somewhat the modern Palinurus in character:
Desmarest, who first described it, in 1822, placing it in that genus.
It has a strongly-marked warty carapace, large outer antenne, and
the first pair of thoracic legs are monodactylous. A number of
small carapaces referred to Paleopemphix by Prof. Gemmellaro,
of Palermo, have been figured and described by him from the
Fusulina-Limestone of Sicily as P. sosiensis, P. affinis, and P. Meyeri;
but no appendages have been found with these carapaces.

Many forms, referred to the genera Glyphwa and Pseudoglyphea,
with the regions of the cephalothorax strongly accentuated, and
having monodactylous thoracic feet, occur in the Jurassic rocks of
this country and of Solenhofen, while species of Glyphea and
Meyeria occur in the Greensand and Chalk of England and Bohemia.

Astacipba.—aAs several of the characters attributed to this tribe
are certainly applicable to some, if not to all, the small forms
referred to Anthrapalemon in the Carboniferous Period, we are
probably justified in considering this as the more generalized
ancestor of all the Astacidea.

No fewer than 39 species of the genus Hryma occur from the
Middle Lias to the Lithographic Stone (=Kimmeridgian), while
Astacus, Pseudastacus, Hoploparia, Enoploclyira, Paleastacus, and
other allied genera carry us through the Cretaceous and Tertiary
series up to the recent Nephrops and Homarus, representing the
marine branch, and to the Potamobiide and Parastacide, the
former embracing all the freshwater forms of Crayfish in the
Northern, and the latter all those in the Southern Hemisphere.

In the Jurassic we also have :—

Eryma Villersu, Oxfordian, Calvados.
In the Cretaceous we have also :—
Pseudastacus hakelensis, O. Fraas.
B: minor, O. Fraas.

Nympheops coesfeldiensis, Schlit., Chalk, Westphalia.
Cambarus primevus, Packard, Lower Tertiary, Wyoming.
Astacus politus of Schliiter, Chalk, Westphalia.
Homarus Bosqueti, Cretaceous, Maestricht.

ar Percyi, Rupelmonde, Brabant.

he Bredai, Pels , Cretaceous, Maestricht.

evi PROCEEDINGS OF THE GEOLOGICAL society. [May 1806,

The existence of this Astacomorphous type from Paleozoic times
exactly corresponds with its remarkable and world-wide distribution
at the present day. The late Prof. Huxley suggested that the
descendants of Hryma in Jurassic times gave rise to Enoploclytia
and Hoploparza in the Cretaceous period, and these to the modern
marine Homarina: per contra—that Pseudastacus, in the Jurassic,
originated the freshwater Potamobiide, which have, in the long
period of time that has since elapsed, not only split up into the
northern and southern potamobine and parastacine types, but have
become distributed from land to land by overland and freshwater
lines of communication, since broken up and removed, but which
must, upon this hypothesis of descent, have formerly existed ; unless
we are prepared to adopt the theory of geographical distribution of
animals, propounded by St. Augustine for insular floras and faunas
—namely, that they were carried there by angels.

The magnitude of the problem of the Astacidea becomes more
apparent when we bear in mind that these freshwater Crayfishes
are distributed over the rivers and lakes of 12 widely separated and
extensive land-areas (each being marked by its own geographical
species), such as the European-Asiatic area, the Amurland, the
Japanese, the West North American and the East North American,
the Brazilian, the Chilian, the New Zealand, the Fijian, the Tas-
manian, the Australian, the Madagascar areas.

It is not without interest to observe the strong cousinly resem-
blance between many of these forms now separated so far by time
and space. ‘Take, for instance, two of the largest living forms—the
Astacoides madagascariensis, from Madagascar, and the Astacordes
armatus, from the Murray River, South Australia; they closely
resemble one another in form and in general structure, although
now separated by the breadth of the great Indian Ocean ; but the
former species is smooth, or only slightly scabrous, while the latter,
as its name suggests, is armed with prickly spines on the sides of
the cephalothorax and the abdominal somites.

This spinose ornamentation may seem trivial, but it is, I believe,
unique of its kind among living Astacides. Strange to say, it finds
its homologue not in another living or fossil form of Crayfish, but
in an ancestor of the marine branch of the Astacidea, the Enoplo-
clytia susseaxiensis from the Chalk of England.

The TuaxasstnipEa form a remarkable family of true fossorial
Macrura, having a long and slender abdomen, the segments of which
do not overlap, and the epimera are feebly developed ; they have also

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT,. evil

a small carapace, compressed on the sides; the eye-stalks are small ;
both pairs of antennz have long peduncles. The first pair of legs
are imperfectly chelate and expanded for digging at their
extremities, the others are shorter and hirsute. The swimming-
plates of the tail are slender and pointed.

The Thalassinz are common on the west coast of Australia and
in the Fiji Islands, and always inhabit deep burrows, which they
excavate in the sand or mud near low water. One fossil species,
Th. Emeryi (Bell), has been described by Prof. Bell from Western
Australia, where Th. scorpiordes is found living.

The genus Callianassa (belonging to the same family) occurs on
the coasts of Ireland, Britain, France, and the Mediterranean, the
shores of North America, and elsewhere. The carapace is small,
without a rostrum ; the abdomen large; the integument is not very
firm. The front legs are large and strong, one hand being very
much more developed than the other; the third pair of legs are
wide near the end, and are used by the animal in digging.

This lobster lives habitually concealed in its burrow with only
its strong chelate fore-limbs projecting, ready to seize on any passing
prey. As aresult of this habit, perfect specimens are seldom to be
obtained, but the great claws are frequently to be seen, both
recent and fossil, in Museums.

A species of the genus Callianassa is met with in the Kimme-
ridge Clay ; one species occurs in the Cretaceous of North America,
ten in that of Europe, and one in the Eocene of the Isle of
Wight. So far as one is able to rely upon the imperfectly preserved
fossil remains, it would appear that the species of this genus have
undergone put little change, and occupy to-day the coasts of
relatively the same areas in which their fossil remains have been
found as far back as the Upper Jurassic.

Upogebia (= Gebia) is an equally active burrowing form, and
closely related to Callianassa, from our own shores and those of
North America. Passing over the Axiide, also closely related, we
come to the Thaumastochelide, established for the genus Thaumasto-
cheles, a very remarkable burrowing form dredged from 450 fathoms
and more, off St. Thomas, in the West Indies, by the Challenyer
Expedition. It is very like the Callianasside in general appear-
ance, but one of the hands is modified into a very strong claw, armed
with a long, slender, and delicate forceps-like chela provided with
slender and very numerous teeth. This curious burrowing form of
Crustacean (Thaumastocheles Zaleucus), living now in deep water

eviil PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

off the West Indies, is represented by two almost identical forms,
described by Prof. Dr. Anton Fritsch, namely, Stenocheles esocinus,
Fr., and Stenocheles parvulus, Fr., both from the Chalk of Bohemia.
Ischnodactylus incequidens, Pelseneer, from the Uppermost Chalk of
Limburg, belongs apparently to the same group of Crustacea.

Is Thaumastocheles Zaleucus a deep-water survival from the Chalk-
sea of Europe, and did its area extend to the West Indies ? |

Dr. Paul Pelseneer has figured and described a cephalothorax of
Galathea (named G. Ubaghsi) from the Maestrichtien or Upper
Chalk of Limburg, and I have received from Miss Caroline Birley
another example of the same genus from the Danien Upper Chalk
of Faxoe. ;

Bracuyvura (Crabs).—Standing between the long-tailed Lobsters
(Macrura) and the short-tailed Crabs (Brachyura) is an anomalous
group of forms, of considerable extent among living Podophthalma,
fortunately, but few of which are met with as fossils, These were
formerly elevated into the rank of a distinct tribe, the ‘ Anomura,’
but a careful consideration soon reveals the fact that this name, like
some still in use in other zoological groups, is but the confession of
our ignorance as to the exact position of the individuals relegated to
such scientific dust-bins.

G. O. Sars has made an earnest effort to clear up the relations of
some of these Anomura, and, from a study of their larval stages,
he is led to refer to the Macrura the following forms, namely :—
Lithodes, Eupagurus, Anapagurus, Munidopsis, Galathea, Munida,
and Porcellana. Of these, Porcellana and Lithodes heretofore had
been placed on the side of the Brachyura, but, tested by their larval
stages, they are really Macrura. On the other hand, the Dromide,
Homolide, Raninide, and Dorippide belong to the anomalous
forms of Brachyura. Such ‘borderland’ genera are among the
familiar difficulties known to every zoologist in the study of any
natural order, even when fossil forms are not, as in the present
instance, taken into consideration.

In this anomalous group we are frequently enabled to penetrate
the veil which Nature too often spreads over her workings, and
to discover the secret of the transformation in appearance which
many of these adult crustacea assume, and detect how it has been
brought about.

Thus we find that all those forms which constantly hide them-
selves in burrows, or in shells of dead mollusks, living sponges,
sea-anemones, and other like hiding-places, become in time quite

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. cix

warped and distorted from their natural shape, by their mode
of life, and lose the use of certain members, which cease to
grow, while others develop peculiarities in structure, or they may,
as in the Soldier-crabs, lose the hard coverings to their bodies.
‘ Dromia does not carry about with it a turbinated shell, like
Pagurus, but clothes itself in the bright skin of its victim, a sea-
lemon (Doris), for example, or encourages a parasitic sponge of
showy colour to grow upon its back, holding it in its place with
its two hind pairs of rudimentary feet, just as the other true
hermit-crabs hold their shells on over their soft-skinned bodies’
(Gosse).

Species of Dorippe from Singapore have been observed by
Dr. Archer, carrying the leaf of a mangrove-tree over their backs,
or the half of a dead bivalve shell, to conceal them from view.

Specimens of Hyas not only dress themselves in living seaweeds,
which they deliberately plant upon their backs, but if their
surroundings be changed they will remove these, and replace them
with some others more suitable in colour—to match with their new
conditions.

In those forms which, like Hippa, Ranina, Zanclifer, and others,
are expert diggers, the body and legs are both specially modified;
enabling the animal to sink down rapidly backward into the wet
sand, or soft mud, and so escape from capture.

Fosstz Forms.—Of some of the oldest forms referred to this
division there is considerable doubt, owing to want of more com-
plete fossil evidence.

Thus, it is not easy to determine the true nature of the genus
Oonocarcinus, of which Prof. Gemmellaro has figured and described
three species from the Fusulina-Limestone of Palermo, Sicily.

With these doubtful forms is associated another, named Para-
prosopon feussii, Gemm., which is certainly referable to the genus
Cyclus.

It is possible that Oonocarcinus may be part of an Arachnid, a
supposition which its ornament suggests. This is certainly the case
with regard to a supposed Brachyurous Crustacean, described by me,
in 1878, under the name of Brachypyge carbonis, from the Coal
Measures of Mons, Belgium. It proves to be almost certainly the
abdomen, not of a Crab, but of an Arachnid near to Hophrynus
Prestvic, H. Woodw., from the Coal Measures of Dudley (Geol.
Mag. 1871, p. 385),

In 1866 I had the pleasure of abdickaptues & a short-tailed crab,

cx PROCEEDINGS OF THE GEOLOGICAL society. _ [May 1806,

from the Forest Marble of Malmesbury, Wiltshire, under the name of
Paleinachus longipes (Quart. Journ. Geol. Soc. vol. xxii. 1866,
pp. 493-4, pl. xxiv. fig. 1), which is still the oldest fossil crab
known.

As the limbs are preserved, as well as the carapace, its deter-
mination is all the more satisfactory and reliable. The legs are
extremely long and slender; in this respect, and also in their form
and in that of the carapace, with its remarkable prominent tubercles
in front, it closely resembles the common ‘ Spider-Crabs —the
Maide and Leptopodide—living on our own coasts at the present
day, and the great Japanese Crab, Mecocheirus Kempferi, of De Haan,
In 1868, I figured and described the carapace of another Brachyuran
Crustacean, but without limbs attached, from the Great Oolite of
Stonesfield, under the name of Prosopon mammillatum The Upper
White Jura of Ulm, Germany, has yielded carapaces of several
minute crustacea, which are either Brachyurous or Anomurous ;
these are generally placed under the Dromiacea, but unfortunately
no limbs or abdominal segments have been found associated with
them. As many as 3 genera and 26 species of these forms
have been figured and described by H:. yon Meyer, Quenstedt,
and Reuss. ,

Although short-tailed or Anomalous Crabs are rare in the
Jurassic Series, they become more abundant in Cretaceous times, —
and we find not only the earliest and simplest forms, such as
Dromiacea, but also representatives of all the great families of the
Brachyura.

Commencing with the Dromtacna, we find a genus, like Dromilites,
which I have named Prosopon Etheridge, occurring in the Cretaceous
of Queensland, Australia; Cyphonotus incertus and Plagiophthalmus
oviformis, from the Greensand of Cambridge and of Wiltshire ;
Diaulax Carteriana, from the Cambridge Greensand, and D. feliceps,
from the Gault, Folkestone ; Platypodia Owent, from the Chalk of
Sussex ; Polycnemiadium pustulosum, from the Chalk of Bohemia ;
Glyphithyreus formosus, from the Pliner-Kalk of Ebendort ; Dro-
miopsis rugosa, from the Chalk of Faxoe ; and Homolopsis Kdwardsi,
from the Gault and Greensand of England.

Dromilites Lamarckui, of Desmarest, and Goniochele angulata, of
Bell, are both London Clay forms from the Isle of Sheppey ; Steno-
dromia is from the Eocene, Biarritz. These complete the Tertiary
record, while about 9 genera and numerous species are widely
distributed over the seas of the world and are still living.

s

Vol. 52.] © ANNIVERSARY ADDRESS OF THE PRESIDENT, "Cxl

In the Ranintnza we have Raninella elongata and R.. Milleri,
from the Cretaceous of Aachen ; Raninoides levis, from the Chalk
of Osnabriick; and Ranina cretacea, Dames, from the Lebanon.
From the Eocene we have Notopus Beyrichii, Bittner, and Palawono-
topus Barroisii, Brocchi, from the Paris Basin; Ranina Marestiana,
Konig, R, speciosa, Minst., and R, bavarica, Ebert, from the
Eocene, Kressenberg, Bavaria, and R, Bouilleana, Milne-Edw., from
the Eocene, Biarritz; Ranina Adamsit, H. Woodw., from the Miocene
of Malta; R. palmea, U. Tertiary, Asti, Piedmont; R. speciosa,
Tertiary, Biinde; &. oblonga, from Ebenda; whilst Ranina scabra
(vel dentata), from Amboina, Raninoides personatus, Notopuides latus;
Notopus dorsipes, Lyreidus tridentatus, L. Bairdii, and Zanclifer.
caribensis, live at the present day on various subtropical coasts.

This concludes all that I have to say regarding the Anomalous
Brachyura. .

In the Oxystomata, or ‘sharp-mouthed’ crabs, which derive
their tribal name from the more or less triangular shape of the
buccal region, the carapace is convex, with the antero-lateral
margins arcuate, orbiculate, subglobose or more or less oblong—
in fact variable in form. These are represented among living
forms by the Dorippide, the Calappide, the Matutide, and the
Leucoside.

The Dortpripz are certainly anomalous forms although placed in
this division, and would seem more suitably located with the pre-
ceding group. ‘The carapace is very broad behind, with projecting
abdominal somites as in Dromia—the last two (4th and 5th) pairs
of legs being short and feeble with strongly hooked extremities,
and carried rather on the dorsal surface—the chelipeds are small,
while the 2nd and 3rd pairs of ambulatory legs are long and adapted
forrunning. The weak and small 4th and 5th legs are probably used
to carry foreign objects on the back for the purpose of concealment,
as noticed by Surgeon-Major Archer at Singapore.

In the Catapripm the carapace is narrow but deep in front, and
expanded behind into thin, broad, shield-like expansions which cover
and conceal the bases of the walking-legs. The chelate fore-limbs
are very flat and strongly crested, like a cock’s-comb, and when
pressed close to the carapace they meet in front and form an
efficient shield to the body.

In the Marutipm, represented by Matuta victor, the 3rd, 4th, and
5th pairs of limbs are suitable either as paddles or for burrowing
in the wet sand, in which they are very expert,

cxil PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

The Leucostapz are small, well-marked crabs, with rather long
chelipeds and a rounded helmet-like carapace, sometimes polished
or covered with minute tubercles, the small eyes being inserted
deeply and near together on the front of the blunt projecting
rostrum: 3 or 4 joints of the abdomen in the female are coalesced
into a broadly rounded convex plate, on the inner concave side of
which the eggs are carried and concealed.

The Oxystomata form the first division of the true Brachyura
represented in the Cretaceous formation by at least 9 genera,
commencing with Necrocarcinus senonensis, Schl., N. Woodwardit,
Chalk, Westphalia, and J. tricarinatus, H. Woodw., from the Green-
sand; followed by NV. avicularis, Fr.,and J. perlatus, Fr., from the
Chalk of Bohemia: thence we pass on to Orithopsis Bonneyi, Carter,
Greensand; and to Orithya Bechet from the Gault, Folkestone, and
O. Woodward: from the Chalk Marl, Isle of Wight. Trachynotus
sulcatus, Greensand, Wiltshire, and Mithracites vectensis, Isle of
Wight, with Hemioon Cunningtoni, Greensand, Wiltshire and Cam-
bridge, leading on to Eucorystes Carteri, Greensand, Cambridge,
Paleocorystes Broderipu and P. Stokesii, Greensand and Gault, Folke-
stone. P. levis is from Westphalia; P. Callanassarum and P. isericus
come from the Chalk of Bohemia; P. Normaniz, Bell, from the Chalk
Marl, Isle of Wight; P. Harveyi, H. Woodw., from the Cretaceous of
Vancouver Island, and P. Mullert from the Chalk of Maestricht.

Passing upward into the Eocene Tertiary we have P. glabra,
Eocene, Portsmouth, and Cyclocorystes pulchellus, Bell, London Clay,
Holloway ; Mithracia libinioides, Bell, and Campylostcema matuti-
formis, Bell, from the London Clay, Sheppey ; Hepatiscus pulchellus,
Bittner, Eocene, Northern Italy, and Egypt; Calappilia verrucosa,
Eocene, Biarritz, and Calappa, sp., Eocene, Hungary ; Typilobus, sp.,
Eocene, East Indies, and atuta, sp., Kocene, Hungary.

In the Miocene and Newer Tertiaries we meet with Atelecyclus,
Miocene and Recent; A. rugosus, Miocene, Montpellier; Paleo-
myra bispinosa, Miocene, Turin; Calappa, sp., Newer Tertiary and
Recent. Hbalia Bryerii, Leach, Suffolk Crag and Recent; Leucosia
subrhomboidalis and L. cranium, Newer Tertiaries and Recent; also
Iva tuberculata. post-Tertiary, East Indies. Corystes Cassivelaunus,
the Masked Crab, is a recent example of the same family.

In the Oxyruyncna, or ‘sharp-snouted’ crabs, represented by
Inachus, Maia, Hyas, Stenorhynchus, etc., the carapace is narrow
anteriorly and is usually provided with a pointed and bifid rostrum,
the hepatic regions of the carapace being small and the branchial

is
ny
a,

Vol. 52.] ANNIVERSARY ADDRESS OF THE PRESIDENT. exill

regions large. The epistome is generally large, and the buccal region
quadrate, with a straight anterior margin.

In long-bodied Crustacea the nervous system is divided into
two parallel chords, with separate ganglia for each segment. In
the Spider-Crabs the nervous system attains a high degree of
concentration, there being only a thoracic and a cephalic ganglion,
instead of about 15 separate centres, as in Homarus. Notwith-
standing this high degree of cephalization, they do not display any
great activity, but are generally of sluggish and slow-moving habits,
their intelligence being principally directed to the arts of disguise
and concealment in which they certainly display much ingenuity,
especially in planting their backs and legs with seaweeds, corallines,
Alcyonia, and the like, which they have been observed to change,
from time to time, the better to suit the colours of their altered
habitats.

This is undoubtedly one of the oldest tribes represented in
geological time, being met with as far back as the Forest Marble
(Great Oolite) of Wiltshire, and it disputes with the Dromiacea the
ancestorship of all the short-tailed Podophthalma.

As before remarked, the earliest known crab is the Paleinachus
longipes, H. Woodw., Forest Marble, Great Oolite, Malmesbury,
Wiltshire. This is followed by Lissiopsis transiens, Fr., from the
Chalk of Bohemia.

Lambrus nummuliticus, Periacanthus horridus, and Micromaja
tuberculata, of Bittner, are all from the Eocene of Vicentino and
other districts of Northern Italy.

Micromithrax holsatica, from the Miocene of Holstein, a species of
Maia from the Miocene of Malta and another from the Coralline
Crag of Suffolk, complete the list of the sharp-nosed crabs.

Cyctometopa.—The crabs which are placed in the tribe of the
Cyclometopa have the carapace arched in front and often broader
than long; more rarely it is quadrate, or suborbicular, but in none
of the members of this division is the carapace rostrate. It includes
the Cancridea, Cyclinea, and Thelphusinea. [The Corystinea I
would prefer to place with the Oxystomata.] Here is located that
most ancient and astronomical genus— Cancer, with Xantho, Ozius,
Trapeza, Carcinus, Portunus, Polybius, Podophthalmus, Thelphusa,
and many more. well-known forms, several being largely eaten
by mankind. Members of the Portunide occur in the Eocene, and
of the Cancride as far back as Cretaceous times.

The Cyclometopa (circular-fronted crabs) of the division Can-

Cxiv PROCEEDINGS OF THE GEOLOGICAL society. [May 1896,

cripm make their first appearance in the Cretaceous Series, with
Xantho Fischeri from the Gault of Neuchatel, and Colaxanthus for-
mosus from the Upper Greensand (Cenomanian) of Le Mans, Sarthe.

Next we find Xanthosia (with 2 species) in the Upper Greensand
of Wiltshire and Cambridge; Htyus (with 3 species from the same
locality as Xanthosia, and one species from the Planer-Kalk of
Bohemia) ; Plagiolophus formosus from the Upper Cretaceous of
Mecklenburg, and Cancer (with one species from Mecklenburg and
3 from the Chalk of Bohemia); Xanthopsis minor, Stolley, Middle
Oligocene, Southern and Northern Germany. Xanthopsis Dufourii,
A. Milne-Edw., Eocene ; Plagiolophus Wetherelli, Bell, Xanthilites
(1 species), Necrozius Bowerbanku, A. Milne-Edw., Xanthopsis (with
4 species)—all from the London Clay of Sheppey ; also 5 species of
Xanthopsis and 1 of Xanthelites from the Nummulitic of Bavaria, of
France, and Germany. itisus, sp., is from the Nummulitic of the
Landes, France.

Paleocarpilius has 6 species, found in the Eocene of Kressen-
berg, the Nummulitic of Verona, of Dax and the Gironde, and the
Calcaire Grossier near Paris. Harpactocarcinus has 8 species from
the Nummulitic of Italy, France, Spain, and New Zealand; and
the genus Neptunus, with 8 species, comes from the Nummulitie of
the Vicentino, of Sassari, and Montpellier, from the Miocene of
Kutch, India, and from Malta.

Podophthalmus has only a single species, from the Tertiary ; and
Syphax crassus is known from the Nummulitic of Aude, France.

Eight species of Cancer occur in the Eocene of France, and in
the Miocene and Pliocene of Italy, etc.

Phlyctenodes, with 2 species, is found in the Nummulitic of
France, and one species in the Miocene of the Vicentino..

Eriphia spinifrons is from the Quaternary of Nice; Galena obscura
from China ; Lobonotus sculptus is known from San Domingo ; Palco-
carpilius, with 2 species, occurs in the Miocene of Kutch, India.

Atergatis, sp., has been obtained from the Miocene of Malta and
A. dubius from that of Dax, Southern France.

A crab which delights in a very remarkable serrated front to
his carapace and also enjoys the longest name extant—Lobocarcinus
Paulino- Wurtemburgensis—occurs very abundantly in the Miocene
beds of the Mokattam quarries near Cairo, Egypt.

Actwa persica is met with in the Newer Tertiary of the Isle of
Kharu, near Bushire, Persian Gulf.

Zozymus Desmaresti is found in the Quaternary of Eastern Asia

-

Wol: 52.| ANNIVERSARY ADDRESS OF THE PRESIDENT. CxXV

Those of the section Porrunip® met with in a fossil state
comprise :—Carcinus peruviensis from the Cretaceous, Peru, and
C. menas, subfossil, Jarrow Docks, Newcastle-on-Tyne ; Portunites
incerta, Bell, London Clay, Sheppey, and Portunites, sp., Miocene,
Malta; Titanocarcinus serratifrons, from the Cretaceous, Ciply,
Belgium ; and five other species from the Nummulitic and Miocene
of Italy and France; Cyamocarcinus angustifrons, Bittner, Kocene,
Schio ; Gonivsoma aniiqua, Milne-Edw., Nummulitic Limestone, Sal-
cedon, Northern Italy, and Menippe Chaw ini, Upper Kocene, Noyon,
France. Scylla Michelini from the Miocene of Anjou, and S. serrata,
Miocene, Malta, Quaternary, Philippines, and also living in the seas
of the Kast Indies. Gontosoma antiqua and Achelous obtusus are
from the Upper Eocene of the Vicentino. Enoplonotus armatus
comes from the Miocene of Monte Bolca, and Psammocarcinus
Hervcarti is from the Lower Eocene of Meaux, France. Rhachisoma
bispinosa and KR. echinata (H. Woodw.) are from the Lower Eocene
of Portsmouth.

The Caromeropa have the front of the carapace bent downwards.
and broader in front, often subquadrate, but not rostrate. The
epistome is short, often almost linear. Here are placed the Gecar-
cinide, the Ocypodide, the Grapside, and the Pinnotheride. It is.
in this tribe that we meet with some of the most active and vigilant.
running forms of Crustacea—the ‘ Land-crabs,’ which inhabit the
warmer regions of the earth north and south of the Equator, and
are able to respire moist air with their gills on land, as effectively as
Cancer, Polybius, and others, breathe aerated water in the sea.

The swift-footed Sand-crabs (Ocypoda) are exclusively terrestrial
animals, and can scarcely live for a single day in water; in a much
shorter period, indeed, if kept in the water, a state of complete
relaxation occurs, and all voluntary movements cease. Members of
this tribe are met with as far back as the Cretaceous period.

In the Catometopa (represented by that interesting, active, and
highly intelligent tribe the existing Land-crabs and Shore-crabs of
subtropical regions) the fossil forms are not nearly so numerous as
in the last division.

Commencing with Podopilumnus Fittona from the Greensand of
Lyme Regis, Dorset, and Lithophylaw in the Chalk, we meet with
Intoricola glabra, H. Woodw., and L. dentata in the Lower Eocene
of Portsmouth (see Quart. Journ. Geol. Soc. vol. xxix. 1873, pl. Il.)
Gdisoma ambiguum, in the London Clay of Sheppey; and an
undoubted Land-crab, Goniocypoda Edwardsu, H. Woodw., from

CXv1 PROCEEDINGS OF THE GEOLOGICAL SocrETY. [May 1896,

the Eocene of High Cliff, Hants. A Paleograpsus, sp., is known
from the Eocene of Northern Italy. Colpocaris bullata comes from
the Nummulitic of ‘Switzerland, Celoma vigil from Vicenza, and
C. taunicum from the Oligocene of Germany; Coloma rupeliense,
Stainier, from the Argile Rupelienne; C. holsaticum, Stolley, from
Holstein. Galenopsis crassifrons, G. Gervilleanus, G. pustulosus,
are all from the Nummulitic of Italy and France; and G. Mur-
chisont is from the Miocene of Sinde, India. Mioplas, sp., is from
the Miocene of Radoboj, Austria. Zelphusa speciosa, T. Quenstedtit,
and Gecarcinus punctatus are from the Miocene of (&ningen;
Glyptonotus trispinosus, Macrophthalmus Latreiller, M. emarginata,
M. incisa, and a species of Gelasimus are from the Island of
Hainan, where they occur in the Quaternary deposits, and are
collected largely for medicine by the Chinese druggists, in whose
pharmacopeeia they form an important item as an antacid and for
the cure of sores.

In this group of Land-crabs we have two genera al species in
the Cretaceous, ten genera and eleven species in the Eocene and
Oligocene, and eight genera and nine species in Miocene and Newer

Tertiary strata.

Last year I invited your attention mainly to the state of our know-
ledge of the earlier and simpler forms of Crustacea inhabiting the
Paleozoic seas, and placed in the great division of the EnromostrRaca.
T referred to the extinct Trilobita and the important advance in our
knowledge of this group which we owe to American paleontologists,
I spoke of the Msrostomara, including therein the Kurypterida
and Xiphosura—the former aquatic division being now entirely.
extinct, but having, no doubt, given origin, in its remote ancestry,
to the terrestrial and air-breathing Scorpionida, which have come
down from the Silurian epoch to our time, apparently but little
changed in structure—while the latter (the living Xiphosura,
‘ King-crabs’) have even adhered, in both their general form and
their aquatic mode of respiration and life, to their Paleozoic
progenitors.

I discussed the Palzozoic ‘ giant Pod-shrimps,’ Phyllocarida,
placed heretofore with the general group of the Phyllopoda—now
claimed as the direct ancestors of the modern Malacostraca—but
still represented by one living form, apparently but little eee
—the genus Nebalia.

Of the other divisions of the Branchiopoda I ae but little, nor

Wol. 52. | ANNIVERSARY ADDRESS OF THE PRESIDENT. exVil

could I do justice to the Ostracoda and Copepoda, while as regards
the Cirripedia, on which Charles Darwin laboured so long and
exhaustively, I have been silent, because I found the whole subject
of the Crustacea too large for the time at my disposal.

To-day I have attempted, in a very imperfect manner, to bring
into the focus of my discourse a summary of the fossil Malaco-
straca, to which our modern Crustacea chiefly belong. It is true
that the evidences of the existence of this division prior to the
Mesozoic epoch are but few and scanty; nevertheless, even in Carbo-
niferous times, if not in still earlier eons, we catch a gleam of the
light of the living life-forms of to-day, shining clearly, though afar
off, down the corridors of time, revealing ancestral forms, the proto-
types of those which people so abundantly our modern seas, proving
that the living present and the far-distant past are indissolubly
linked together, and that the stream of life has flowed, from its
parent source, through all time, at first in tiny rills and murmuring
streamlets, yet ever growing stronger, ‘from running brooks to
rivers wide,’ pressing ever and for ever, onward, from the river to
the sea.

As to the minute details of the course which the evolution of
Crustacean life has followed in past times, we can, in many cases,
only infer, we cannot absolutely prove our proposition.

Thus we have no doubt that the aquatic Eurypterida gave rise
to the terrestrial Scorpionida, but we cannot show any direct
evidence, because we have Hurypterus and Scorpio side by side in
Upper Silurian rocks, but the earlier evolutionary history is still
wanting.

Again, Nebalia-like forms are most probably in the direct line of
the ancestry of the modern Malacostraca, and in the Carboniferous
period we have Cumacea-like forms, which have doubtless been
derived from Ceratiocaris and have given rise to higher Malaco-
straca ; but Macruran and other forms of Podophthalma and
Edriophthalma were already in existence in the Devonian, and
both Cumacez and Nebaliz continue to exist unchanged at the
present day.

Looked at broadly, however, the Crustacea show the same upward
and onward development which marks other living forms whose
history can be traced. The great extinct orders of Kurypterida and
Trilobita have disappeared—the other Entomostracan orders have
survived, but they no longer occupy the whole field: with the close
of Paleozoic times the Malacostraca have developed in strength, and

VOL. LII. v

CXVill PROCEEDINGS OF THE GEOLOGICAL socleTY. [May 1896,

now occupy the stage associated with the Tracheata proper, and the
King-crabs and Scorpions, which latter, like the Ostracoda and
Phyllopoda, are survivals from a pre-Silurian age.
Truly—
‘The old order changeth, yielding place to new.’

My task is ended, and it now only remains my duty to efface
myself officially, but before doing so I should lke to express to
the Council and Officers, and to the Fellows generally, my grateful
sense of the honour which they conferred upon me when they placed
me in this chair, and for the generous support and friendly for-
bearance which they have extended towards me in the performance .
of my duties. In this matter I cannot fail to recall how greatly I
am indebted to the Secretaries and Treasurer, for the valuable
assistance and advice which I have at all times received from them
and from the permanent staff of the Society, without whose aid I
could never have carried on the work devolving upon me.

In resigning the Presidential chair to my esteemed friend and
successor, Dr. Henry Hicks, F.R.S., I feel that he is neither a
stranger among us, nor inexperienced, for he has served as your
Secretary for three years (1890-91-92), and has moreover had
many years’ experience on the Council of this Society.

May he thoroughly enjoy, as I have done, the two chief
pleasures of office—that of taking the chair and that of resigning it.
Farewell. .

Wael. 52.| PROCEEDINGS OF THE GEOLOGICAL SOCIETY. CX1X

February 26th, 1896.
Dr. Henry Hicas, F.R.S., President, in the Chair.

William Griffith, Esq., Waterloo Hotel, Aberystwith, South
Wales; Joseph Colin Francis Johnson, Esq., J.P., Adelaide, and
Constitutional Club, London ; Peter MacLaren, Esq., 352 St. Vincent
Street, Glasgow ; and Edwin Perkins Ridley, Esq., 6 Paget Road,
Ipswich, were elected Fellows of the Society.

The List of Donations to the Library was read.

The following communications were read :—
fo)

1. ‘On the Structure of the Plesiosaurian Skull.’ By Charles W.
Andrews, Esq., B.Sc., F.G.S.

2. ‘On certain Granophyres, modified by the Incorporation of
Gabbro Fragments, in. Strath (Skye).’ By Alfred Harker, Ksq.,
M.A.. F.G.8. (Communicated by permission of the Director-
Generai of H.M. Geological Survey.)

3. ‘Observations on the Geology of the Nile Valley, and on the
Evidence of the greater Volume of that River at a former Period.’

By Prof. E. Hull, M.A., LL.D., F.B.S., F.G.S.

4. ‘The Fauna of the Keisley Limestone.—Part I.’ By F. R.
Cowper Reed, Hsq., M.A., F.G.S.

The following specimens, maps, and photographs were ex-
hibited :—

Cast of Skull of Plestosawrus macrocephalus, Buckland, exhibited
by C. W. Andrews, Esq., B.Sc., F.G.S., in illustration of his paper.

Specimens of Granophyres from Strath (Skye), exhibited by
Alfred Harker, Esq., M.A., F.G.S., in illustration of his paper.

Fossils from the Keisley Limestone of Westmoreland, exhibited by
F. R. Cowper Reed, Esq., M.A., F.G.S., in illustration of his paper.

Human Skull, found about 6 feet beneath the surface, not far
from the banks of the Wye, somewhat below the city of Hereford,
exhibited by the Rev. J. O. Bevan, F.G.S.

Geological Survey of England and Wales, New Series, 1-inch
Map (Solid and Drift) Sheet 249, Newport (Mon.), by A. Strahan
and W. Gibson, 1895, presented by the Director-General of H.M.
Geological Survey.

Photographs of Stratified Volcanic Ash at Tantallon Castle, and
of Boulders trom the Bagshot District, etc., exhibited by Horace W.
Monckton, Esq., F.L.S., F.G.S. ;

CXX PROCEEDINGS OF THE GEOLOGICAL socieTy. {May 1896.

March 11th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.

George C. Bond, Esq., Aspley House, Nottingham; Sydney
Fawns, Esq., F.C.S., 16 Onslow Gardens, S8.W.; and Dr. J.
Shearson Hyland, 3 Copthall Buildings, E.C., were elected Fellows
of the Society.

The List of Donations to the Library was read.

The PresrpENT announced that, in connexion with the Hungarian
Millennial Exhibition, a Congress of Mining and Geology would be
held at Budapest on September 25th and 26th, 1896.

The following communications were read :—

1. ‘On an Alpine Nickel-bearing Serpentine with Fulgurites.’
By Miss E. Aston, B.Sc. With Petrographical Notes by Prof. T.
Geabonney, Disc ali Dy RRs V PIGS:

2. ‘The Pliocene Glaciation, Pre-Glacial Valleys, and Lake Basins
of Subalpine Switzerland; with a Note on the Microscopie Strue-
ture of Tavayanaz Diabasic Tufa.’ By C.S. Du Riche Preller, M.A.,
Ph.D., F.G.8., F.C.8., A.J.M.LE., M.1.E.E.

3. ‘Notes concerning certain Linear Marks in a Sedimentary
Rock.’ By Prof. J. E. Talmage, D.Sc., F.G.S.

The following specimens, photographs, and maps were ex-
hibited :—

Specimens and microscope-sections of Alpine Nickel-bearing
Serpentine with Fulgurites, exhibited by Prof. T. G. Bonney, D.Sc.,
F.R.S., V.P.G.8., in illustration of the paper by Miss E. Aston and
himself.

Specimens, photographs, and microscope-section, exhibited by
C. 8. Du Riche Preller, M.A., Ph.D., F.G.S., in illustration of his

aper.

; Specimens and photographs of Linear Marks in an Argillaceous
Sandstone, exhibited by Prof. J. HE. Talmage, D.Sc., F.G.8., in
illustration of his paper.

Fossils from the Marine Permian of the Salt Range, India,
exhibited by F. G. Brook-Fox, Esq., F.G.S.

And the following maps presented by the Austro-Hungarian
Geological Survey :—Geologische Specialkarte der Umgebung von
Wien, von Dionys Stur (in 6 sheets, scale ui) Geologische
Karte der ostlichen Ausliufer der Karnischen und Julischen
Alpen, von Friedrich Teller (in 4 sheets, scale aw) 3 and Geo-
logische Karte von Olmiitz, von Emil Tietze (scale =a

Vol. 52. | PROCEEDINGS OF THB GEOLOGICAL SOCIETY. CXxl

March 25th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair,

Thomas Wilberforce Davies, Esq., 3 Burns Avenue, Liscard,
Cheshire, was elected a Fellow of the Society.

The List of Donations to the Library was read.

The following communications were read :—

1. ‘On Submerged Land-surfaces at Barry, Glamorganshire.’
By A. Strahan, Esq., M.A., F.G.S. With Notes on the Fauna and
Flora by Clement Reid, Esq., F.L.S., F.G.S., and an Appendix on
the Microzoa by Prof. T. Rupert Jones, F.R.S., F.G.S., and
F. Chapman, Esq., A.L.S., F.R.M.S. (Communicated by permission
of the Director-General of H.M. Geological Survey.)

2. ‘On a Phosphatic Chalk with Holaster planus at Lewes.’ By
A. Strahan, Esq., M.A., F.G.S. With an Appendix on the Ostracoda
and Foraminifera by F. Chapman, Esq., A.L.S., F.R.M.S. (Commu-
nicated by permission of the Director-General of H.M. Geological
Survey.)

3. ‘On the Classification of the Strata between the Kimeridgian
and the Aptian.’ By Dr. A. P. Pavlow, Professor of Geology in the
University of Moscow, For.Corr.G.8.

The following specimens, photographs, and maps were exhibited :—

Specimens and photographs exhibited by A. Strahan, Esq., M.A.,
F.G.S., in illustration of his two papers.

Fossils exhibited by G. W. Lamplugh, Esq., F.G.S., and the
Curator of the Woodwardian Museum, Cambridge, in illustration of
the paper by Prof. A. P. Pavlow, For.Corr.G.8.

Geological Survey of England and Wales, l-inch Map, New Series,
Sheet 14, Morpeth (Solid and Drift), by H. H. Howell, W. Topley,
G. A. Lebour, and G. Barrow; also Sheet 343, Weymouth, by
C. Reid and A. Strahan, presented by the Director-General of H.M.

Geological Survey.

April 15th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.

Henry Slade Childe, Hsq., Assoc.M.Inst.C.E., Home Garth,
Wakefield; Stanley William Ford, Esq., 180 Cromwell Road, S.W.;
James Douglas Hay, Esq., 17 Adamson Road, Belsize Park, N.W. ;
Osbert Henry Howarth, Esq., C.E., 259 Gresham House, Old Broad
Street, E.C.; and Hastings Montague Page, Esq., College of Science,

VOL;. Lit. k

CXXil PROCEEDINGS OF THE GEOLOGICAL socieTy. [Aug. 1896,

Poona, Bombay, were elected Fellows ; Prof. Albert Heim, of Ziirich,
was elected a Foreign Member; and Prof. 8. L. Penfield, of New
Haven (Conn.), and Dr. J. Walther, of Jena, were elected Foreign
Correspondents of the Society.

The List of Donations to the Library was read.

The Presipent announced that a portrait in sepia of Prof. Bonney,
executed by Mr. Trevor Haddon, had been presented to the Society
by 34 subscribers, Feliows of the Society.

The following communications were read :—

1. ‘The Junction-Beds of the Upper Lias and Inferior Oolite in
Northamptonshire.— Part I. Physical and Chemical.’ By Beeby
Thompson, Esq., F.G.S., F.C.8.!

2. ‘Contributions to the Stratigraphy and Paleontology of the
Globigerina-limestones of the Maltese Islands.’ By J. H. Cooke,
Bisqi, HaL.S. KGS:

3. ‘On the Geology of the Neighbourhood of Carmarthen.’ By
Miss Margaret C. Crosfield and Miss Ethel G. Skeat. (Commu-
nicated by J. E. Marr, Esq., M.A., F.R.S., Sec.G.8.)

The following specimens, etc., were exhibited :—

Specimens and photographs, exhibited by Beeby Thompson, Esq.,
F.G.S., in illustration of his paper. .

Specimens of Trilobites, Graptolites, etc., from the Rocks of the
Carmarthen District, exhibited by J. E. Marr, Esgq., F.R.S., Sec.G.S.,
on behalf of Miss Margaret C. Crosfield and Miss Ethel G. Skeat, in
illustration of their paper.

Specimen of the Phosphatic Bed at the base of the Inferior Oolite
Series, Tianavaig, Skye, collected by H. B. Woodward, Esgq., F.G.S.,
and exhibited by the Director-General of H.M. Geological Survey.

Sheet 11 of the Geological Survey of England and Wales, scale
4 miles to 1 inch, presented by the Director-General of H.M. Geo-
logical Survey.

April 29th, 1896.

Dr. Henry Hicks, F.R.S., President, in the Chair.
EK. Hubert Cunningham-Craig, Esq., B.A., Clare College, Cam-
bridge ; William Foggin, Esq., 12 Devonshire Place, Jesmond,

Newcastle-on-Tyne; and Henry Ernest Hurst, Esq., Kalcoorlie,
South Norwood Hill, 8.E., were elected Fellows of the Society.

1 Withdrawn by permission of the Council.

Vol. 52.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. CXxill
The List of Donations to the Library was read.

The following communications were read :—

1. ‘Descriptions of New Fossils from the Carboniferous Lime-
stone.—I. On Pemmatites constipatus, sp. nov., a Lithistid Sponge.
Il. On Paleacis humilis, sp. nov., a new Perforate Coral; with
Remarks on the Genus. III. On the Jaw-apparatus of an Annelid,
unites Reidie, sp. nov. By George Jennings Hinde, Ph.D.,
F.R.S., F.G.S.

2. ‘The Eocene Deposits of Dorset’ By Clement Reid, Esq.,
F.LS., F.G.S. (Communicated by permission of the Director-
General of H.M. Geological Survey.)

3. ‘Discovery of Mammalian Remains in the Old River-gravels
of the Derwent near Derby.—Part I. By H. H. Arnold-Bemrose,
Ksqg., M.A., F.G.S. Part I]. By R. M. Deeley, Esq., F.G.S.

The following specimens were exhibited :—

Specimens and microscope-sections of Fossils from the Carboni-
ferous Limestone, exhibited by Dr. G. J. Hinde, F.R.S., F.GS.,
in illustration of his paper.

A series of Pebbles from the Reading and Bagshot Beds of Dorset,
exhibited by Clement Reid, Esq., F.L.S., F.G.S., in illustration of
his paper.

Mammalian Remains (Hippopotamus, Elephas, and Rhinoceros)
from the old River-gravel at Allenton, near Derby, exhibited by
H. H. Arnold-Bemrose, Esq., M.A., F.G.8., and R. M. Deeley, Ksq.,
F.G.8., in illustration of their paper.

May 13th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.

J. McClelland Henderson, Ph.D., Box 1146, Johannesburg, 8.A.R.;
James Gunson Lawn, Esq., 7 Amerland Road, Wandsworth, 8.W. :
and Thomas Wilkins, Esq., 19 Lyndhurst Road, 8.E., were elected
Fellows of the Society.

_ The List of Donations to the Library was read.

The following communications were read :—

1. ‘An Account of a Head or Gateway driven into the Eastern
Boundary-fault of the South Staffordshire Coal Field.’ By William
Farnworth, Esq., F.G.S.

CXXI1V PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Aug. 1896,

2. ‘On the Geographical Evolution of Jamaica.’ By J. W.
Spencer, M.A., Ph.D., F.G.S."

3. ‘Dundry Hill: its Upper Portion, or the Beds marked as
Inferior Oolite (G 5) in the Maps of the Geological Survey.’ By
S. 8. Buckman, Esq., F.G.S., and E. Wilson, Esq., F.G.8.

The following specimens and photographs were exhibited :—

Specimens of Rocks and Fossils (Ammonites, etc.), exhibited by
S. 8. Buckman, Esq., F.G.8., and E. Wilson, Esq., F.G.S., in illus-
tration of their paper.

Photographs of the Old Quarries at Tilly Whim, and of Durleston
Head, Swanage, exhibited by Horace W. Monckton, Esq., F.L.S.,
F.G.S.

Coal-Measure Sandstone from Gornal near Dudley, exhibited by
W. Farnworth, Esq., F.G.S., on behalf of the Rev. W. A. H. Lewis.

May 20th, 1896.
Special General Meeting—8 p.m.
Dr. Henry Hicks, F.R.S., President, in the Chair.

On behalf of the Council the Presrpent submitted the following
resolution to the Meeting :—

‘That it is desirable that the collections of specimens
belonging to the Geological Society, with the exceptions
specified in the Reports of the Special Museum Committee
adopted by the Council on November 20th and December 4th,
1895, be transferred to the British Museum, subject to the
conditions provisionally accepted by Sir William Flower on
behalf of the Trustees of the British Museum.’

The following amendment was then moved by Mr. Hupiseston
and seconded by Col. Gopw1n-AUstEN :

‘That such portions of the Society’s collections as illustrate
papers in the Society’s publications, or have a special interest
in connexion with the history of geology in this country, be
retained, but that all other portions may be disposed of.’

This amendment was afterwards withdrawn, and the previous
question, moved by Mr. Huprzston and seconded by Mr. CarRuTHERs,
was voted by 35 Ayes to 12 Noes.

? Withdrawn by permission of the Council.

hols 522] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. CXXY

May 27th, 1896.
Dr. Henry Hicks, F.R.S., President, in the Chair.

Martin Stanger Higgs, Esq., Clarence House, Gloucester; Thomas
James Moss-Flower, Esq.,Carlton Chambers, Baldwin Street, Bristol ;
and Edwin Percy Richards, Esq., 17 Market Street, Edenfield, Bury,
were elected Fellows of the Society.

The List of Donations to the Library was read.

The Prestpent announced that a portrait in oils of the late
Prof. Huxley had been presented to the Society by Sir John Evans,
K.C.B., For.Sec.G.8.

The following communications were read :—

1. ‘On the Pliocene Deposits of Holland, and their Relation to
the English and Belgian Crags: with a Suggestion for the Establish-
ment of anew Zone “ Amstelien” and some Remarks on the
Geographical Conditions of the Pliocene Epoch in Northern Europe.’
By F. W. Harmer, Esq., F.G.S.

2. ‘The Lingula-Flags and Igneous Rocks of the Neighbourhood
of Dolgelly.’ By Philip Lake, Esq., M.A., F.G.S., and S. H. Rey-
nolds, Esq., M.A., F.G.S.

3. ‘The Kildare Inlier.’ By 8. H. Reynolds, Esq., M.A., F.GS.,
and C. I. Gardiner, Esq., M.A., F.GS.

The following specimens were exhibited :—

Fossils, rock-specimens, and microscope-sections, exhibited by
Philip Lake, Esq., M.A., F.G.S., and §. H. Reynolds, Esq., M.A.,
F.G.S., in illustration of their paper.

Rock-specimens, microseope-sections, and photographs, exhibited
by 8. H. Reynolds, Esq., M.A., F.G.S., and C. I. Gardiner, Esq.,
M.A., F.G.S., in illustration of their paper.

June 10th, 1896.
Dr. Henry Hicxs, F.R.S., President, in the Chair.

Walter Taylor, Esq., 6 Upper Chorlton Road, Brooks Bar,
Manchester, was elected a Fellow of the Society.

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.

CXXV1 PROCEEDINGS OF THE GEOLOGICAL soctETy. [Aug. 1896,
The List of Donations to the Library was read.

The following communications were read :—

1. ‘On Foliated Granites and their Relations to the Crystalline
Schists in Eastern Sutherland.’ By J. Horne, Esq., F.R.S.E.,
F.G.S., and E. Greenly, Esq., F.G.S. (Communicated by permission
of the Director-General of H.M. Geological Survey.)

2. ‘The Geology of the Eastern Corner of Anglesey.’ By EK.
Greenly, Esq., F.G.S.

3. ‘Seismic Phenomena in the British Empire. By M. F.
de Montessus de Ballore, Captain of Fortress Artillery at Belle-Ie-
en-Mer. (Translated by L. L. Belinfante, B.Sc., B. és L. Com-
municated by Sir Archibald Geikie, D.Sc., F.R.S.)

The following specimens, etc., were exhibited :—

Rock-specimens from Eastern Sutherland, with microscope-
sections, exhibited by J. Horne, Esq., F.R.S.E., F.G.S., and
K. Greenly, Esq., F.G.S., in illustration of their paper.

Microscope-sections and rock-specimens from East Anglesey, with
photographs and 6-inch map, exhibited by E. Greenly, Esq., F.G.S.,
in illustration of his paper.

Tooth of Cestracion rugosus from the Upper Chalk, Strood,
Rochester, exhibited by G. E. Dibley, Esq., F.G.S.

June 24th, 1896.

Dr. Henry Hicks, F.R.S., President, in the Chair.

The Prusment said: It is with deep regret that I have to
announce to you the death of our dear and much-beloved friend,
Sir Joseph Prestwich. He was elected into the Society in the year
1833, and we had come to look upon him as the father of our
Society. He served it as Treasurer and President, and was one of
its Wollaston Medallists, and we feel that by his death our Society
loses one of its truest friends. He always gave us of his best, and
delighted to communicate his knowledge to his fellow-workers. He
was in every respect a typical representative of our Society and its
objects, for he passionately loved the science, fearlessly maintained
what he believed to be the truth, and had that open mind and
craving for knowledge which have ever characterized the best and

Vol. 527] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. CXXVil

noblest of its members. This is not the time to refer specially
to his labours; but we may feel assured that such sterling work as
he accomplished will ever hold an honoured place in the annals of
British Geology. The Council at their sitting this afternoon passed
the following resolutions, which I feel no doubt all the Fellows
present will cordially endorse :—

(1) That the President, Council, and Fellows of the Geo-
logical Society of London desire to convey to Lady Prestwich
the assurance of their heartfelt sympathy with her in the sad
and irreparable loss that she has sustained, and at the same
time to place on record their high appreciation of the lifelong
geological work achieved by Sir Joseph Prestwich, who for
sixty-three years was a member of their body alike respected
and beloved.

(2) That this Resolution be placed upon the Minutes, and
that a copy of it be communicated to Lady Prestwich.

The above Resolutions were then passed unanimously.

Humphrey Lewis, Esq., Cambrian House, Llangollen; Geoffrey
F. Monckton, Esq., Vancouver, British Columbia ; and William
Sherwood, Esq., Eastbourne House, Sutton Coldfield, were elected
Fellows 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 their Arrears of
Contributions :—the Rey. J. T. C. Guriran; F. M*Knieur, Esq. ;
E. P. Ramsay, Esq.; and R. H. Witiiams, Esq.

The List of Donations to the Library was read.

Sir Witt1am Dawson, C.M.G., F.R.S., exhibited specimens and
lantern-slides illustrating the general form, arrangement of lamine,
and distribution of the canals and tubuli in characteristic specimens
of Hozoon canadense. He pointed out that an examination of these
specimens and photographs might prevent mistakes likely to arise
from the study of imperfect specimens or from supposing that
laminated rocks resembled Eozoon, and also that they exhibited
additional peculiarities observed since the original publication of the
description of Hozoon in the Quarterly Journal of the Society in 1865.
He did not wish to enter upon any argument as to the nature of
Eozoon, but merely to show the appearance of the principal struc-
tures on which the conclusion that it was of animal origin had been
based. He also pointed out that these structures might be mis-
understood when studied in imperfectly-preserved specimens, and

CXxvili § PROCEEDINGS OF THE GEOLOGICAL society. [Aug. 1896.

that the wonder was not that so many specimens were imperfect,
but that any structure had been preserved. He also shortly noticed
the growing probabilities in favour of the existence of a rich marine
fauna in pre-Cambrian times, and some of the discoveries in this
direction already made or in progress.

The following communications were read :—

1. ‘Notes on the Glacial Geology of Arctic Europe and its
Islands.—Part II. Arctic Norway, Russian Lapland, Novaya
Zemlya, and Spitsbergen.’ By Col. H. W. Feilden, F.G.S. With
an Appendix by Prof: T. G. Bonney, D.Se., LL.D ase
V.2:G:s.

2. ‘Extrusive and Intrusive Igneous Rocks as Produete of
Magmatic Differentiation.’ By Prof. J. P. Iddings, For.Corr.G.S.

The following specimens, etc., were exhibited :—

Rock-specimens and fossils, exhibited by Col. H. W. Feilden,
F.G.8., in illustration of his paper.

Lantern-slides and microscopic sections of Hozoon canadense, ex-
hibited by Sir J. William Dawson, C.M.G., F.R.S., F.G.S.

Sheet 7 (N.W. Wales) of the Geological Survey Index Map,
on the scale of 4 miles to 1 inch, presented by the Director-General
of that Survey.

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- ADMISSION AND PRIVILEGES
OF

FELLOWS OF THE GEOLOGICAL SOCIETY OF LONDON.

Eyery Candidate for admission as a Fellow must be proposed by three or more Fellows,
who must sign a Certificate in his favour. The Proposer whose name stands first upon —

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Fellows on election pay an Admission Fee of Six Guineas. The Annual Contribu-—

tion paid by Fellows is Two Guineas, due on the Ist of January in every year, and
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and Fellows elected in November or December pay no Contribution for the current
year. The Annual Contribution may at any time be compounded for by a payment of
Thirty-Five Pounds,

The Fellows are entitled to receive gratuitously all the volumes or parts of volumes
of the Quarterly Journal of the Society that may be published after their election,

so long as their Annual Contributions are paid; and they may purchase any of the —

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The Library is open daily to the Fellows between the hours of 10 and 5 (except .

during the first two weeks of September), and on Meeting days until 8 P.M. >
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Publications to be had of the Geological Society, Burlington House.

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= Sith. 8.
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QUARTERLY JOURNAL. (Vols. III. to LI. inclusive.)

Price to Fellows, 13s. 6d. each (Vols. XV., XXIII., XXX., and XXXIV. to LI.
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CLASSIFIED INDEX TO THE TRANSACTIONS, JOURNAL,
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GEOLOGICAL MAP OF ENGLAND AND WALES, in 6 Sheets, by
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THE GEOLOGY OF NEW ZEALAND. Translated by Dr. 0. F. Fiscanr,

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CATALOGUE OF THE LIBRARY, 1880. (620 pages 8vo.) Price 8s. Od.
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during the half-year ended Dec. 1894. Price 2s. To Fellows 1s. 6d. [Postage 1d.].
Do. during the year ended Dec. 1895. Same price [Postage 23d. ].

CONTENTS,

PAPERS READ. ae
34. Messrs. 8. H. Reynolds & C. I. Gardiner on the Kildare Inlier. ate XVII, 4 38 ;

35. Prof, J. P. Iddings on Extrusive and Takeusive Igneous Rocks as Produts of.
/ Magmatic oe (Plate. XXIK:) 2 5-22 a ae ee

36. Mr. E. Greeny on the Geology of ihe Eastern Corner of Anglesey as see

37. Messrs. J. Horne & E. Greenly on Foliated Granites and their Relations to F x
the pekloon oi Schists in Eastern Sutherland ............. Reo RY. theteecenens ss

38. M. F. de Montessus de Ballore on Seismic Phenpnieny in the British Binpire4 = |
(GaIEY 2 pe..6.C o>. 8 45 5A Primer here tered eer a se ate 651

39. Messrs. 8. 8. Buckman & E. Wilson on Dundry Hill: its Upper Portion, or
the Beds marked as Inferior Oolite (g 5) in the Geol. Surv. Maps ......... 669

40, Col. H. W. Feilden on the Glacial Geology of SE Norway, Russian tap.
land, Novaya: Zemlya, &% Spitsbergen co ei. ic cc .0- cess en edyclungs ovat eiyenaeemnee

41. Mr. F. W. Harmer on the Pliocene hoe of Bone (Plates XXXIV.&
es ashi Gnbetnn setinicee opt Wace cote. de «be e@enevd Pha eet each cohen 448

(Titnepacs, Inprx, TABLE oF Fcrnanet ETC. TO Vou, LIT.)
[No. 209 will be published on the Ist of next February. ]

[The Editor of the Quarterly Journal is directed to make it known to the Public, that die
Authors alone are responsible for the facts and opinions contained 1 in their respective u:
Papers. | i

*,* The Council request that all communications intended for publication by the =
Baciets shall be clearly and legibly written on one side of the paper only, with proper fo
references, and in all respects in fit condition for being at once placed in the Printer’s
hands. Unless this is done, it will be in the discretion of the Officers to return the
communication to the Author for revision: i

The Library and Museum at the Apartments of the Society are open every Weekday —
from Ten o'clock until Five, except during the first two weeks in the month ms
of September, when the Library will be closed for the purpose of cleaning; the —
Library is also closed on Saturdays at One p.m. during the months of August
and September. It is open until Eight p.m. on the Days of Meeting for the
joan of books, and from Hight p.m. until the eid of a Hes oS :
conversational purposes only, fees

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